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ethylen eo xide ethyleneoxide third edition third edition Legal Notice The Ethylene Oxide Product Stewardship Neither the American Chemistry Council, nor the Guidance Manual was prepared by the American individual member companies of the Ethylene Chemistry Council’s Ethylene Oxide/Ethylene Oxide/Ethylene Glycols Panel, nor any of their Glycols Panel (Panel). It is intended to provide respective directors, officers, employees, general information to persons who may handle subcontractors, consultants, or other assigns, or store ethylene oxide. It is not intended to makes any warranty or representation, either serve as a substitute for in-depth training or express or implied, with respect to the accuracy specific handling or storage requirements, nor is or completeness of the information contained it designed or intended to define or create legal in this manual; nor do the American Chemistry rights or obligations. It is not intended to be a Council or any member companies assume any “how-to” manual, nor is it a prescriptive guide. All liability or responsibility for any use or misuse, persons involved in handling and storing ethylene or the results of such use or misuse, of any oxide have an independent obligation to ascertain information, procedure, conclusion, opinion, that their actions are in compliance with current product, or process disclosed in this manual. federal, state and local laws and regulations and NO WARRANTIES ARE GIVEN; ALL IMPLIED should consult with legal counsel concerning WARRANTIES OF MERCHANTABILITY OR FITNESS such matters. The manual is necessarily general FOR A PARTICULAR PURPOSE ARE EXPRESSLY in nature and individual companies may vary their EXCLUDED. approach with respect to particular practices This work is protected by copyright. Users are based on specific factual circumstance, the granted a nonexclusive royalty-free license to practicality and effectiveness of particular actions reproduce and distribute this Manual, subject and economic and technological feasibility. Any to the following limitations: (1) the work must be mention of specific products in this manual is reproduced in its entirety, without alterations; and for illustration purposes only and is not intended (2) copies of the work may not be sold. as a recommendation or endorsement of such products. For more information on material presented in this manual, please contact your supplier. Copyright © May 2007 ethyleneoxide third edition To the Reader Manual Preparation Tom Grumbles Sasol North America As members and affiliated companies of the Susan Jackson BASF Corporation American Chemistry Council, we support efforts to Robert Lenahan Bayer MaterialScience LLC improve the industry’s responsible management Denis Reeser The Dow Chemical Company of chemicals. To assist in this effort, the American Chemistry Council’s Ethylene Oxide/Ethylene John Stewart BASF Corporation Glycols Panel supported the creation and Don Szczepanski Huntsman Petrochemical publication of this manual. The Panel is comprised Corporation of the following companies: David Townsend Celanese Chemicals Ltd. Balchem Corporation/ARC Specialty Products Randy Viscomi Balchem Corporation/ARC BASF Corporation Specialty Products Bayer Material Science LLC Keith Vogel Lyondell Chemical Company Celanese Ltd. Mike Wagner Old World Industries Champion Technologies John Wincek Croda, Inc. Croda, Inc. Gerald Wise Shell Chemical LP The Dow Chemical Company Acknowledgements Eastman Chemical Company Many others contributed to the development and Honeywell editing of this manual, all of whom cannot be listed Shell Chemical LP here; however, the manual work group would like to The development of this manual was led by the thank the following individuals for their significant Panel’s Ethylene Oxide Safety Task Group (EOSTG), contributions to this publication: a group comprised of producers and users of Ralph Gingell Shell Chemical LP ethylene oxide. The EOSTG functions to generate, William Gulledge American Chemistry Council collect, evaluate and share information to support product stewardship with regard to ethylene oxide. Karl Loos Shell Chemical LP The EOSTG formed a manual work group, chaired David McCready The Dow Chemical Company by Keith Vogel of Lyondell Chemical Company, Kristy Morrison EO STG Manager, American to lead the development of this document. The Chemistry Council following work group members provided significant contributions: Karyn Schmidt Assistant General Counsel, American Chemistry Council

Table of Contents

1.0 Introduction ...... 1 6.0 Design of Facilities . . . . . 39 1.1 Purpose and Use of Manual . . . 1 6.1 Introduction ...... 39

2.0 Properties of Ethylene Oxide . 2 6.2 Plant Layout and Siting . . . 39 2.1 Introduction ...... 2 6.3 Materials of Construction . . 40 2.2 Physical Properties . . . . . 3 6.4 Unloading Facilities – Bulk Receipt of EO . . . . . 46 2.3 Reactive and Combustive Properties ...... 5 6.5 EO Storage ...... 49 2.4 Commercial Chemistry . . . 14 6.6 Reaction Systems . . . . . 54 2.5 Uses of Ethylene Oxide . . . 15 6.7 Piping and Pumps . . . . . 57 6.8 Handling of Vents and 3.0 Health Effects of Effluent ...... 63 Ethylene Oxide ...... 16 6.9 Miscellaneous ...... 66 3.1 Introduction ...... 16 3.2 Acute Inhalation Exposure . . . 16 7.0 Personnel Exposure . . . . . 68 3.3 Skin and Eye Contact ...... 16 7.1 Introduction ...... 68 3.4 Chronic Exposure Hazards . . 16 7.2 OSHA Standard for Ethylene Oxide ...... 68 4.0 Environmental Effects of 7.3 Other Exposure Standards/ Ethylene Oxide ...... 18 Recommendations for 4.1 Introduction ...... 18 Ethylene Oxide ...... 68 4.2 Properties in the Environment 18 7.4 Measuring Exposure ...... 70 4.3 Ecotoxicological Effects . . . . . 21 7.5 Personal Protective 4.4 Environmental Evaluation of Equipment ...... 70 Ethylene Oxide Spills . . . . 21 8.0 Equipment Preparation 4.5 Fugitive Emissions . . . . . 22 and Maintenance ...... 82 5.0 Hazards of Ethylene Oxide . . . 23 8.1 Introduction ...... 82 5.1 Introduction ...... 23 8.2 Preparation for Inspection or Maintenance ...... 82 5.2 Contamination Incidents . . 23 8.3 Preparation of Internal 5.3 Formation of Ethylene Oxide Surfaces ...... 83 Vapor Clouds ...... 27 8.4 Leak Repair Clamps . . . . 83 5.4 Ethylene Oxide Decomposition Incidents ...... 27 8.5 Preventive Maintenance . . . . . 84 5.5 Ethylene Oxide Transportation 8.6 Equipment Commissioning . 84 Incidents ...... 35 9.0 Transportation and 5.6 Runaway Ethylene Oxide Unloading Operations ...... 85 Polymerization Incidents . . . . 36 9.1 Introduction ...... 85 5.7 Runaway Reactions in 9.2 Emergency Response Ethoxylation Units . . . . . 36 Telephone Numbers . . . . 85 5.8 Incidents in Ethylene Oxide 9.3 Ethylene Oxide Classification 85 Abatement Devices ...... 37

9.4 Railcars ...... 85 11.0 Selected Regulations . . . 105 9.5 IM Portable Tanks 11.1 Introduction ...... 105 (Intermodal/Iso-Containers) . 94 11.2 Regulations — Numerical 9.6 Non-Bulk Packaging for with Subject Listed ...... 105 High Purity Ethylene Oxide . 94 Appendix A 9.7 Ethylene Oxide Shipping Figures and Tables . . . . . 118 Data ...... 98 9.8 Shipments of Ethylene Oxide Appendix B between the U.S. and Laboratory Compatibility Canada ...... 98 Testing of Elastomers with Ethylene Oxide ...... 137 10.0 Emergency Response . . . 100 Appendix C 10.1 Introduction ...... 100 Railcar Repressurization . . . . .141 10.2 Potential Hazards . . . . . 100 Appendix D 10.3 Fire Response ...... 101 References ...... 145 10.4 Spill Response ...... 102 Appendix E 10.5 Emergency Response to Glossary of Selected Temperature Rise . . . . . 102 Terms, Abbreviations and 10.6 Emergency Response Plan Organizations ...... 151 to Temperature Rise ...... 103 10.7 Use of Water in Emergencies ...... 104

Figures Figure 5.9 Remnants of Railcar (after EO explosion caused Figure 2.1 The Ethylene Oxide by contamination with Molecule ...... 2 ammonia) ...... 26 Figure 2.2 Flammable Region of Figure 5.10 High Speed Centrifugal Ethylene Oxide/Nitrogen/Air Pump “Launched” by Mixtures ...... 7 Decomposition of 0.6 Pounds Figure 2.3 Flammable Region of of Ethylene Oxide . . . . 29 Ethylene Oxide/Carbon Figure 5.11 Motor Landed on Operating Dioxide/Air Mixtures ...... 7 Ethylene Oxide Pump Figure 2.4 Effects of Pressure on Discharge Line ...... 29 Flammable Region of Figure 5.12 Ethylene Oxide Distillation Ethylene Oxide/Nitrogen/Air Column Reboiler after Mixtures ...... 8 Explosion ...... 30 Figure 2.5 Ethylene Oxide Polymer Figure 5.13 Aerial View of Ethylene Instantaneous Drop-Out Oxide Plant after Explosion . 31 Temperatures ...... 13 Figure 5.14 Remnants of Base of Figure 2.6 Ethylene Oxide Polymer Ethylene Oxide Distillation Drop-Out Temperatures Column after Explosion . . . . 31 after 4 Days ...... 14 Figure 5.15 Piece of Ethylene Oxide Figure 4.1 Neutral EO/Water/Glycol Distillation Column Wall Kinetics - Isothermal Case, Turned Inside Out by Initially EO/Water mixture . 19 Explosion ...... 32 Figure 4.2 Neutral EO/Water/Glycol Figure 5.16 Aerial View of EO Unit Kinetics - Adiabatic Case, After Explosion ...... 33 Initially EO/Water . . . . . 19 Figure 5.17 EO Plant Burning Figure 5.1 Older View of Plant Before after Explosion ...... 33 Explosion Showing EO Tanks in Foreground ...... 23 Figure 5.18 EO Purification After Explosion – Two Towers Figure 5.2 Blast Center after are Missing ...... 34 Explosion – EO Vessels No Longer Visible ...... 23 Figure 5.19 Ethylene Oxide Re-distillation Tower Explosion . . . . . 34 Figure 5.3 Aerial View of the Plant Showing Overall Damage . 24 Figure 5.20 Resulting Damage to the Plant ...... 34 Figure 5.4 EO Tank Blown Into Process Structure 400 Feet Away . 24 Figure 5.21 Filter Case after Runaway Polymerization ...... 36 Figure 5.5 Plant Laboratory After EO Vapor Cloud Explosion, Figure 5.22 Filter Case after Runaway 300 Feet Away from Polymerization ...... 36 Explosion Center . . . . . 25 Figure 5.23 Filter Case after Runaway Figure 5.6 Remnants of Railcar . . . 25 Polymerization ...... 36 Figure 5.7 Remnants of Railcar . . . 25 Figure 5.24 Diagram of Sterilizer Explosion ...... 37 Figure 5.8 Damage to Other Railcars from Ethylene Oxide Railcar Figure 5.25 Sterilizer Explosion Explosion ...... 25 Damage ...... 38

Figure 5.26 Sterilization Chamber Figure 6.11 Example of Severely Damage ...... 38 Degraded O-ring in High Figure 5.27 Damage to the building Temperature EO-water wall from impact of sterilizer Service (Chemraz® 505) . . 44 door ...... 38 Figure 6.12 Example of Flange Seal Figure 6.1 Degradation of Compressed Band with Leak Detection Asbestos Valve Bonnet Drip Tube ...... 45 Gaskets by Ethylene Oxide . 41 Figure 6.13 EO Unloading Facilities . . 46 Figure 6.2 PTFE Gasket Failures in EO Figure 6.14 Representative layout of Service Due to Cold Flow . 41 Ethylene Oxide unloading Figure 6.3 Glass Filled PTFE Gasket facilities – Pressurized Failure Due to EO transfer ...... 47 Polymerization in Figure 6.15 Representative layout of PTFE-Glass Matrix . . . . 42 Ethylene Oxide unloading Figure 6.4a Deformation of a Spiral Wound facilities – Pump transfer . 48 Stainless Steel-PTFE Gasket Figure 6.16 Total pressure required to Due to EO Permeation and inert vapor above Ethylene Polymerization ...... 42 Oxide with nitrogen diluent 51 Figure 6.4b Deformation of a Spiral Figure 6.17 EO Decomposable Limits Wound Stainless Steel-PTFE versus Molar Nitrogen Gasket ...... 42 Concentration ...... 56 Figure 6.5 Spiral Wound Gasket with Figure 6.18 Decomposition Limit of Stainless Steel Windings, Mole % EO versus Total Flexible Compressed Graphite System Pressure . . . . . 57 Filler, and Inner and Outer Figure 6.19 Ethylene Oxide Vent Retaining Rings ...... 43 Scrubber System . . . . . 63 Figure 6.6 Gasket Test Showing Failure Figure 6.20 Schematic of Typical of Compressed Graphite Flaring System ...... 65 Gasket, Laminated on Flat Stainless Steel Sheet with Figure 6.21 EO Sampling System ...... 67 an Adhesive ...... 43 Figure 7.1 OSHA Warning for EO Figure 6.7 Laminated Gasket Made of Regulated Areas . . . . . 69 Polycarbon Sigraflex™ Figure 7.2 Chemical Burn Resulting BTCSS Flexible Compressed from Low Concentration Graphite – Laminated on of EO in Water ...... 70 Stainless Steel Tang Sheet . 43 Figure 9.1 DOT 105-J railcar for Figure 6.8 Laminated Gasket Made of transporting Ethylene Oxide 86 UCAR Grafoil GH™ E Flexible Figure 9.2 Dome Arrangement of a Compressed Graphite – DOT 105-J Railcar for Laminated on Stainless Ethylene Oxide Service . . . . 87 Steel Tang Sheet . . . . . 43 Figure 9.3 DOT “Stop—Tank Car Figure 6.9 Butyl Rubber O-Ring Before Connected” Sign . . . . 88 and After Exposure to EO for 30 days ...... 44 Figure 9.4 Canister Mask with Ethylene Oxide-Specific Canister . . 90 Figure 6.10 Example of Degraded O-ring Attacked by EO . . 44

Figure 9.5 Positive Pressure “Hoseline” Figure 16 Flammability Data on EO-Air Type Respirator . . . . . 90 Mixtures at Subatmospheric Figure 9.6 Commonly Used Non-bulk Pressures ...... 128 Containers ...... 95 Figure 17 Vapor/Liquid Equilibria of Figure 9.7 Typical Drum Connections . 96 Ethylene Oxide/Water Systems ...... 129 Figure 10.1 Ethylene Oxide / Water (Neutral) Reaction Figure 18 Density vs. Composition of Temperature Profile ...... 103 Ethylene Oxide/Water Systems ...... 130 Figure 1 Ethylene Oxide Liquid Density ...... 118 Figure 19 Boiling points of aqueous EO concentrations . . . . 131 Figure 2 Ethylene Oxide Vapor Pressure ...... 118 Figure 20 Decomposition Data . . . 132 Figure 3 Ethylene Oxide Liquid Figure 21 Vapor Compressibility vs. Heat Capacity ...... 119 Pressure as a Function of Temperature ...... 133 Figure 4 Ethylene Oxide Liquid Viscosity ...... 119 Figure B1 Weight Change of O-rings Exposed to EO at 27°C . . 138 Figure 5 Ethylene Oxide Liquid Thermal Conductivity . . . . . 120 Figure B2 Volume Change of O-rings Exposed to EO at 27°C . . 138 Figure 6 Ethylene Oxide Heat of Vaporization ...... 120 Figure B3 Tensile Strength of O-rings Exposed to EO at 27°C . . 140 Figure 7 Ethylene Oxide Vapor Heat Capacity ...... 121 Figure B4 Maximum Deformation of O-rings Exposed to EO Figure 8 Ethylene Oxide Vapor at 27∞C ...... 140 Viscosity ...... 121 Figure C1 Unloaded Railcar Figure 9 Ethylene Oxide Vapor Repressuring — Nitrogen — Thermal Conductivity . . . . . 122 Less than 50 Gallon Figure 10 Freezing Points Ethylene EO Heel ...... 142 Oxide/Water Mixtures . . 122 Figure C2 Unloaded Railcar Figure 11 Cp/Cv For Saturated Repressuring — Vapor Ethylene Oxide Vapor . . 123 Balancing — Less than Figure 12 Ethylene Oxide Vapor 50 Gallon Heel . . . . . 144 Density ...... 123 Figure 13 Ethylene Oxide Coefficient of Cubic Expansion . . . 124 Figure 14 Raoult’s Law Deviation Factors for Ethylene Oxide/ Water Mixtures . . . . . 126 Figure 15 Raoult’s Law Deviation Factors for Ethylene Oxide/ Water Mixtures . . . . . 127

Tables Table 7.2 OSHA Minimum Standards for Respiratory Protection for Table 2.1 Physical Properties of Airborne Ethylene Oxide . . 72 Ethylene Oxide ...... 3 Table 7.3 Ethylene Oxide Permeation Table 2.2 Physical Properties of Data for Clothing . . . . . 73 Aqueous Ethylene Oxide Solutions ...... 5 Table 7.4 Ethylene Oxide Permeation Data for Gloves . . . . . 79 Table 2.3 Heat of Reaction of Various Ethylene Oxide Reactions Table 7.5 Ethylene Oxide Permeation at 25°C ...... 6 Data for Boots ...... 81 Table 2.4 Physical Properties of Table 9.1 Illustration – Pressuring Ethylene Oxide Polymer . . 12 Unloaded Railcars with Pure Nitrogen (Assuming Table 2.5 Solubility* of Ethylene 50 Gallon Ethylene Oxide Liquid Oxide Polymer in Various Heel) ...... 93 Solvents ...... 13 Table 9.2 Illustration – Repressuring Table 3.1 Carcinogenicity Unloaded Railcars – Vapor Classifications of Balancing (50 Gallon Ethylene Ethylene Oxide ...... 17 Oxide Liquid Heel) . . . . 94 Table 3.2 Findings of the NIOSH Table 9.3 Temperature/Density/Vapor Ethylene Oxide Studies . . 17 Pressure for Shipping Table 4.1 Environmentally Relevant Ethylene Oxide ...... 98 Parameters of Ethylene Table A1 Physical Property Oxide ...... 18 Equations ...... 134 Table 4.2 Biological Degradation Table A2 Conversion Factors . . . 134 Data for Ethylene Oxide . . 20 Table A3 Henry’s Law Constants Table 4.3 Aquatic Toxicity Data for (Atm/mole fraction) . . . 135 Ethylene Oxide* . . . . . 21 Table A4 Henry’s Law Constants Table 6.1 EO Pump Shutdown and (MPa/mole fraction) . . . 135 Alarm Considerations . . . 62 Table B1 O-Rings Selected for Table 7.1 AEGL Values for Ethylene Compatibility Testing . . 137 Oxide [ppm (mg/m3)] ...... 69

1.0 Introduction

1.1 Purpose and Use of Manual Manual Availability and Updates This manual has been developed for use by This document is available through your supplier producers and industrial users of ethylene in hard copy and is available on a password- oxide. The purpose of this product stewardship protected Web site hosted by the Panel at www. document is to provide the reader with a better ethyleneoxide.com. This document may be understanding of how ethylene oxide is used to updated. Interim updates may occur on the Web produce products that play important roles in our site posting of this document only. Readers lives. It is also our intent to address the health, should consult the Web site for the most recent safety and environmental aspects associated with version of this manual. Readers should also stay manufacturing, distributing, using and disposing abreast of new developments and information of ethylene oxide and the bulk of the material about ethylene oxide, including but not limited presented emphasizes these topics. to physical properties, handling technology, and This information is provided as a resource in the regulatory requirements that occur after the date development of producers’ and users’ design, of publication of this document. operation, maintenance, training and emergency Contact your supplier to obtain the most current response practices. References to applicable version of this manual, if you have questions or regulations, industry practices are made in to get more information about any information tables and text. Contact your supplier for further presented in this document. We encourage information as necessary. comments on the content of this document and Note that a separate, independent group of a more in-depth dialogue concerning the issues ethylene oxide producers previously produced presented. two editions of an ethylene oxide guidance manual: Ethylene Oxide User’s Guide, First (1995) and Second (1999) Editions. It is the intention of those producers that this manual supercedes the Ethylene Oxide User’s Guide, First and Second Editions.

2.0 Properties of Ethylene Oxide

2.1 Introduction

Figure 2.1 The Ethylene Oxide Molecule

1.43 Å 61.62º

1.09 Å 1.46 Å

116.9°

Ethylene Oxide (EO), sometimes referred to as automotive antifreeze. Other EO derivatives include oxirane, is the simplest cyclic ether. It is a colorless surfactants, solvents, amines and poly(ethylene) gas or liquid and has a sweet, etheric odor. The glycols. EO also has several direct uses, including structure of an EO molecule is shown in Figure 2.1 use as a sterilant and the treatment of spices above. The C-C bond is short and the bond angles and other foodstuffs. United States production of strained [1]. Because its highly strained ring can be EO in 2004 was 8,315 million (8.3 billion) pounds, opened easily, EO is highly reactive. according to National Petrochemical & Refiners EO was first prepared in 1859 by Wurtz [2] Association’s (NPRA) Petrochemical Surveys using potassium hydroxide solution to eliminate 4 Quarter 2003 (published January 27, 2005), hydrochloric acid from ethylene chlorohydrin. The highlighting its role as an important industrial chlorohydrin process developed from Wurtz’s chemical. discovery and industrial production of EO began The highly reactive nature of EO, which helps in 1914. The direct catalytic oxidation of ethylene, make it a versatile and commercially important discovered in 1931 by Lefort [3], has gradually chemical intermediate, also underlies some of the superseded the chlorohydrin process. Currently, main hazards of EO – in particular, its flammability, EO is produced by direct oxidation of ethylene with reactivity, explosive vapor decomposability and air or oxygen. toxicity. Understanding the properties of EO is Virtually all EO produced is further reacted important to managing its use. (Section 2.4) to derivative products. Its most important derivative is ethylene glycol, which is used for the manufacture of polyester and in

2.2 Physical Properties Important physical properties of EO are summarized in Table 2.1, below.

Table 2.1 Physical Properties of Ethylene Oxide

Ethylene Oxide Chemical Abstracts Name: Oxirane Chemical Abstracts Number: 75-21-8 PSUID Code: 1441 UN CODE: 1040 IUPAC Name: Oxirane

Synonyms: Ethylene Oxide 1,2-Epoxyethane Dihydrooxirene Oxacyclopropane Dimethylene Oxide Oxidoethane Epoxyethane EO, ETO

Other Names: Ethene oxide; Oxane; Oxirene, Dihydro-; Oxyfume; Oxyfume 12; T-Gas; Aethylenoxid; Amprolene; Anprolene; Anproline; ENT-26263; E.O.; 1,2-Epoxyaethan; Ethox; Ethyleenoxide; Etylenu tlenek; FEMA No. 2433; Merpol; NCI-C50088; a,b-Oxidoethane; Oxiraan; Oxiran; RCRA waste number U115; Sterilizing gas ethylene oxide 100%; C2H4O [37]

Structural Formula: CH2OCH2

Note(s)/ Property SI Units Engineering Units [References]

Molecular Weight 44.053 44.053 Critical Temperature 469.15°K 384.8°F

Critical Pressure 7,191 kPa 1,043 psia Critical Volume 0.00319 cu m/kg 0.051 cu ft/lb

Critical Compression Factor 0.2588 0.2588 AIChe DIPPR (r) Melting Point 160.65°K -170.5°F Database

Triple Point Temperature 161.46°K -169.1°F 1 Triple Point Pressure 0.0078 kPa 0.00113 psia

Normal Boiling Point 283.6°K 50.8°F AIChe DIPPR (r) at 101.325kPa (1atm) Database

Liq. Sp. Gr. 20°C/20°C (68°F/(68°F) 0.875 0.875 Liq. Volume @ 25°C (77°F) 0.00113 cu m/kg 0.018 cu ft/lb 2

Coefficient of Cubical Expansion, 0.00158/°K 0.00088/°F [37] at 20°C (68°F) 579.5 kJ/kg 249.2 BTU/lb Heat of Vaporization

Entropy of Vaporization 2.04 kJ/kg*°K 0.488 BTU/lb*°F [37] Heat of Formation – Ideal Gas -1,194.8 kJ/kg -514 BTU/lb [37, 58, 59]

Heat of Formation – Liquid -1766.5 kJ/kg -760 BTU/lb [59] Gibbs Energy of Formation – Ideal Gas -300.3 kJ/kg -129.15 BTU/lb 4

Gibbs Energy of Formation – Liquid -267 kJ/kg -115 BTU/lb 3 Absolute Entropy – Ideal Gas 5.52 kJ/kg*°K 1.319 BTU/lb*°F [37, 59]

Absolute Entropy - Liquid 3.494 kJ/kg*°K 0.835 BTU/lb*°F 3 [59] Heat of Fusion at Melting Point 117.5 kJ/kg 50.52 BTU/lb [37]

(continued on page 4)

Table 2.1 (continued from page 13)

Note(s)/ Property SI Units Engineering Units [References]

Entropy of Fusion 0.73 kJ/kg*°K 0.175 BTU/lb*°F [36]

Standard Heat of Combustion, -29,076 kJ/kg -12,509 BTU/lb 5 Liquid HHC (HHV) (to water condensed)

Standard Heat of Combustion, -27,649 kJ/kg -11,895 BTU/lb 5 Gas LHC (LHV) (to water as vapor)

Standard Heat of Combustion, -29,647 kJ/kg -12,755 BTU/lb 5 Gas HHC (HHV) (to water condensed)

Heat of Solution in Water -142.7 kJ/kg -61.35 BTU/lb Acentric Factor 0.197 0.197

Radius of Gyration 1.937E-10 m 6.355E-10 ft Dipole Moment 6.3E-30 C*m 1.889 Debye

Liq Dielectric Const at 0°C (32°F) 14.5 14.5 Vapor Dielectric Const at 15°C (54.5°F) 1.01 1.01 [10]

Electrical Conductivity (liq) 4E-06 Siemens/m 4E-08 mhos/cm van der Waals Volume 5.485E-04 cu m/kg 0.008785 cu ft/lb

van der Waals Area 7.492E+06 m sq/kg 3.658E+07 ft sq/lb

Refractive Index, nD at 6.8°C (44.3°F) 1.3597 1.3597

Flash Point <255.16°K <0°F Flammability Limits 2.6-100 vol.% 2.6-100 vol.%

Fundamental Burning Velocity, Pure EO 0.027m/s 0.089 ft/s [58] Autoignition Temp (in Air) 718.15°K 833°F [60]

Decomposition Temp (at 760 mm Hg) ~773°K ~932°F 6, [17]

NOTES: 1. Estimated to be equal to the melting point temperature. 2. Determined at the normal boiling point. 3. Estimated from CRC 1994 Handbook of Thermophysical and Thermochemical Data. 4. Calculated from the enthalpy of formation and the absolute entropy. 5. Calculated from heats of formation. 6. Decomposition temperature affected by pressure, container surfaces, volume, and geometry. Decomposition temperature has been reported as low as 842°F (723.2°K) and as high as 1060°F (844°K)

WARNING: FLAMMABILITY LIMITS ARE DETERMINED AT 77°F (298°K) AND 1 ATMOSPHERE. HIGHER TEMPERATURES AND/OR HIGHER PRESSURES WILL LOWER THE LOWER LIMIT.

Graphs and tables of selected temperature- are due to hydrate formation [4]. Hydrates consist dependent properties of EO are provided in of organic molecules enclosed by water molecules Appendix A. in a cage structure. The highest melting point observed is 52°F (11.1°C) and corresponds to a Ethylene Oxide Water Mixtures hydrate composition of C2H4O • 6.89 H2O [5]. Table 2.2 on the next page shows some of the Liquid EO and water are completely miscible in properties of aqueous EO solutions. Of particular each other in all proportions, but due to differences note are the relatively high melting points, which in density, may not initially mix in the absence

Table 2.2 Physical Properties of Aqueous Ethylene Oxide Solutions [9,10]

SG at 50/50°F EO Content Melting Point Bubble Point (10/10°C) wt% °F (°C) °F (°C) Flash Point °F (°C)

0 32 (0) 212 (100) 1.0000

0.5 107 (41.5)

1 31.3 (-0.4) 88 (31)

2 37 (3)

3 29.7 (-1.3)

5 29.1 (-1.6) 136.4 (58) 0.9977 28 (–2)

10 42.1 (5.6) 108.5 (42.5) 0.9944

20 50.7 (10.4) 89.6 (32) 0.9816 -6 (-21)

30 52 (11.1) max 80.6 (27) 0.9658 -18 (-28)

40 50.7 (10.4) 69.8 (21) 0.9500 -31 (-35)

60 46 (7.8) 60.8 (16) 0.9227 -49 (-45)

80 38.7 (3.7) 55.4 (13) 0.9005 -63 (-53)

100 -169 (-111.7) 50.7 (10.4) 0.8828 -71 (-57) of any agitation (i.e., it is possible to have two 2.3 Reactive and Combustive separate phases if one is added beneath the Properties surface of the other without mixing). EO/water Understanding the reactivity and combustion mixtures are highly non-ideal and do not follow properties of EO is important to managing its use. Raoult’s Law. Raoult’s Law deviation factors for EO/ As described in Chapter 5, serious incidents have water mixtures are shown in figures 14 and 15 in occurred during the processing, storage, and Appendix A. transportation of ethylene oxide. Solubility of Ethylene Oxide Gas Combustion/Flammability The solubility of EO gas in various compounds EO is a flammable, explosible chemical. Its fire and has been measured and reported at atmospheric explosion characteristics are system-dependent. pressure and 72–74°F (22–23°C) by Chaigneau Some of the characteristics for EO/air mixtures are [41]. These compounds include water, alcohols, as follows. hydrocarbons, oils, chlorocompounds, esters and waxes. • The minimum value cited for the lower flammable limit of EO air mixtures is 2.6% [20]. Solubility of Gases in Ethylene Oxide • The upper flammable limit is typically stated The solubility of gases in liquid EO vary, increasing to be 100% because pure EO can violently in the order nitrogen, argon, methane and ethane. decompose with a significant release of heat in Increasing temperature tends to increase the the absence of air or oxygen. solubility. The Henry’s Law Constants for these • Accordingly, the flammable range of EO-air gases in EO at different temperatures are given in mixtures is 2.6–100%. Appendix A [7].

Table 2.3 Heat of Reaction of Various Ethylene Oxide Reactions at 25°C

Note kJ/kg BTU/lb [Reference]

Combustion

Liquid HHC (to water condensed) -29,076 -12,509 1 Gas LHC (to water as vapor) -27,649 -11,895 1 Gas HHC (to water condensed) -29,647 -12,755 1

Decomposition -3,051 -1,312 [59] -3,013 -1,296 (calc from gas heats of formation)

Isomerization to acetaldehyde -2,621 -1,127

Polymerization -2,324 -1,000 [13, 17]

Hydrolysis -2064 -887 [46]

NOTE: 1. Calculated from heats of formation.

• The autoignition temperature of EO in air at Flammability of Ethylene Oxide 14.7 psia is 833°F (445°C) [21]. and Water Mixtures This temperature can be lower with the presence Due to the flash characteristics of EO/water of certain impurities such as water, acetaldehyde, mixtures, it can be difficult to extinguish fires of and rust. these liquid mixtures until the EO reaches a certain Figures 2.2 and 2.3 illustrate the flammable limits dilution. In closed systems such as sewers, 100 to 1 for EO, air and either nitrogen or carbon dioxide water to EO dilution ratios (vol/vol) may be required ternary mixtures at atmospheric (14.7 psia) pressure to produce a mixture, the vapor of which will not (101.325kPa) [39]. The literature also indicates support combustion. In open systems, such as some variability in the boundary concentration around an atmospheric spill, water/EO mixtures of demarcation separating the flammable and non- less than 22 to 1 (vol/vol) can generate sufficient flammable regions. [38, 39, 59]. Also, it is important vapors to support combustion. to recognize that mixture pressure also affects the flammability characteristics. Figure 2.4 illustrates Ignition Energy and Static Electricity the effects of pressure on the flammability region Liquid EO is an electrically conductive fluid that for EO/Nitrogen/Air. Thus, more or less dilution cannot accumulate static electricity charges in with an inerting gas may be required to maintain metal containers having internal parts properly a non-flammable condition depending on whether bonded and grounded (see NFPA 77 Static the pressure is greater or less than atmospheric Electricity Guide). Bottom filling is therefore pressure. generally not needed unless there are isolated internal areas that might accumulate a charge. The flammable limits of other mixtures of EO with If containers have non-conductive linings, such various gases and air can be found in the literature. as glass or plastic, use of an uncoated grounded See Appendix D for examples: EO with H 0 [22]; 2 metal device in contact with the contained liquid at N [23], [22]; N -H 0 [24]; C0 -H 0 [24]; CH [15]; 2 2 2 2 2 4 all times provides effective grounding of the liquid. C02 [6], [22], [25]; C3H6 [26]; C4H9 [26]; N2-air [6]; At standard conditions and in the absence of air, CH4-air [6]; CO2-air [20]; CF2Cl2-air [27], [28]; CO2-air, pure EO vapor minimum ignition energy (MIE) is N2-air, R12-air, R134a-air [39]; CO2-air, N2-air, Steam- air [24]; MeBr-air [24]. about 1000 mJ [9]. While this minimum EO ignition

Figure 2.2 Flammable Region of Ethylene Oxide/Nitrogen/AirOxide/Nitrogen/Air MixturesMixtures

0 100 Initial Conditions: Temperature: 20°C Pressure: 1 atm. 20

80 EO Concentration (% Vol)

40 60

60 40

Nitrogen Concentration (% Vol) Flammable Region 80 20

100 0 0 20 40 60 80 100

Air Concentration (% Vol)

Figure 2.3 FlammableFlammable Region of Ethylene Oxide/Carbon Dioxide/Air MixturesMixtures

0 100 Initial Conditions: Temperature: 20°C 20 Pressure: 1 atm. 80

EO Concentration (% Vol)

40 60

60 40

80 Flammable Region Carbon Dioxide Concentration (% Vol) 20

100 0 0 20 40 60 80 100

Air Concentration (% Vol)

FigureFigure 2.42.4 EffectsEﬀects of of Pressure Pressure on on Flammable Flammable Region Region of Ethyleneof Ethylene Oxide/Nitrogen/Air Oxide/Nitrogen/Air Mixtures Mixtures

0 100

20 EO Concentration (% Vol) (% Vol) 80

40 60

Concentration 60 1/2 atm 40

Nitrogen 80 3 atm Flammable Region 20

100 0 0 20 40 60 80 100

Air Concentration (% Vol)

energy decreases with increased temperature and from ordinary spark plugs is ca. 20-30 mJ [31]. Note pressure, a static energy discharge is much lower that people cannot usually feel sparks carrying than the MIE and is not a significant hazard under less than about 2 mJ.) Thus, various mixtures of normal liquid storage and handling conditions. EO vapor and air can be easily ignited by a static EO liquid discharged into the vapor space of a spark, even by the low discharge levels that might properly inerted storage tank in the absence of be generated by a person. EO in air also has a oxygen will not carry sufficient energy to ignite the much wider flammability range (2.6-100%) than vapor. either gasoline (1.4-7.6%) or hydrogen (4.0-75%). At standard conditions and in the presence of air, Consequently, static discharge is a very important the MIE of EO is in the range of 10,000–100,000 mJ consideration in the design and operation of at just above the lower flammable limit (2.6 mol%) equipment. See Eichel [32] for a discussion of and is about 1000 mJ at the upper flammable limit electrostatic calculations. (100 mol%) [58]. However, between these upper The NFPA 77 Static Electricity Guide provides and lower flammable limits, the ignition energy guidance for bonding and grounding equipment in follows a “skewed parabolic” contour with changes EO service. In general, the NFPA Guide provides that in composition that reaches a minimum value of flanged connections do not need external bonding 0.06 mJ at about 10.4 mol%. Comparing minimum wires, but that users should consider using external ignition energies, EO in air at these concentrations bonding wires where electrical continuity might has a minimum ignition energy less than gasoline appear questionable (for example, where specially vapor (0.24mJ), and only somewhat greater than coated bolting materials are in use, in areas hydrogen (0.01-0.02mJ). (Routine movement of near swivel joints, or if a non-conductive item of a person can typically initiate static discharge equipment is placed in a line). For static grounding, energy in the range of 1-50 mJ, while the energy the NFPA Guide notes that all metal parts should have a resistance to ground of 1M Ω or less.

To minimize the potential for static buildup, increase to 20 times the initial pressure if liquid samples or small quantities of EO are generally EO is present. This phenomenon occurs because obtained using grounded metal portable containers liquid EO evaporates and participates in the with conductive linings. Use of non-conductive decomposition reactions which take place in the plastic bottles and pails should be performed vapor phase [15]. only with great caution. If circumstances, such EO liquid mists will decompose explosively similarly as laboratory settings, necessitate their use, the to EO vapor. The decomposition of these two- container should be bottom filled (submerged) phase mixtures yields greater pressures and rates using a grounded conductive dip tube resting of pressure rise than the vapor alone [17]. Liquid on the bottom of the container to minimize EO can participate in a decomposition that starts splashing and turbulence. Where a transparent in the vapor phase. Explosion of liquid EO, initiated sample container is required (such as for clarity by a strong ignition source within the liquid, was inspection), use of a glass container helps minimize first described in 1980. It is thought that the ignition static charge buildup. Avoid rubbing or cleaning the source vaporizes liquid EO and the decomposition container immediately prior to filling or emptying as reaction takes place in the gas phase. another means of avoiding buildup of static charge. (See Section 6.9 for further discussion of sample It has been reported in the literature that pure EO system design.) vapor, when ignited in a closed-end system, can undergo a transition from decomposition flame Decomposition to a detonation shock wave with a propagation speed of approximately 1 mile (1,600 meters) per Pure EO vapor or EO vapor mixed with air or an second [47]. This phenomenon, which destroyed insufficient amount of inert gases can decompose a 12-inch (0.3 meter) pipe test apparatus, can explosively. The primary decomposition reaction is generate overpressures that are orders of expressed by the following equation: magnitude greater than the maximum theoretical

EO (C2H4O) CO + CH4 + 1312 BTU/lb overpressure. The progression of a decomposition The reaction can also produce ethane, ethylene, flame front to a detonation shock wave can result hydrogen, carbon and acetaldehyde [10, 17]. in a highly destructive event. The literature cited above concluded that certain specific conditions At atmospheric pressure, thermal decomposition of equipment size, pressure, and temperature of pure EO vapor occurs at 932°F (500°C) [17]. were necessary for a deflagration to transition to a Both lower and higher gaseous EO decomposition detonation. See Chapter 5 for more information and temperatures have been reported – indicating illustrative incidents. that decomposition temperature is affected by pressure, surface characteristics, volume and Mixtures of EO with nitrogen, carbon dioxide geometry. EO can also ignite and decompose and methane will not decompose over certain explosively below atmospheric pressures, down to concentration ranges; thus, the risk of vapor a pressure of around 4.8-5.8 psia, but at greater decomposition can be minimized by dilution with than 932°F (500°C). a suitable inert gas. Nitrogen is most commonly used for dilution, although other inert gases Once the decomposition reaction has been and methane have been used on occasion. initiated, it can be propagated from the ignition Note that carbon dioxide is not typically used source through the gas phase as a flame (i.e., as a dilutent due to its high solubility in EO. reaction zone) and, under certain conditions, may The dilution quantity depends on temperature, be explosive. It is important to understand that this pressure and the expected ignition source and reaction can occur in the absence of air or oxygen. duration [9]. The most thorough discussion of (Note that a number of sources consider a flame the EO decomposition process is presented in a region of combustion, whereas combustion is Reference [17]. The minimum total pressure for defined as the oxidation of a fuel source.) inert blanketing is important [9, 10], and Section High pressure can be generated by decomposition 6.5 presents information relevant to the inerting of EO. The maximum theoretical explosive pressure of EO in storage and handling systems. Chapter 9 is about 10 times the initial pressure but this can provides information concerning the inerting of

transportation containers. Inerting of vapor spaces in contact with high surface area metal oxides,

of reactors using EO as feeds or reagents is such as the gamma form (Fe2O3) of iron oxide, can discussed in Section 6.6. undergo disproportionation reactions that can raise local temperatures above the decomposition Deflagration and Detonation of temperature of EO. Ethylene Oxide in Piping In this particular incident the disproportionation Unpublished work by Union Carbide performed reaction occurred within the tubes of a distillation in 1956 provided some information on the topic column reboiler, in the presence of a deposit of of EO vapor decomposition flame propagation, high surface area rust embedded in an EO polymer suggesting that at pressures up to 75 psia, EO matrix, when flow through the reboiler was reduced decomposition flames would not be expected to by a process upset. The loss of reboiler circulation propagate indefinitely through vented, horizontal allowed for rapid heat buildup in the vicinity of pipe with a diameter of less than 2 inches. the iron oxide/polymer deposit, accelerating the In the late 1990s, the American Chemistry Council’s disproportionation reactions which then progressed Ethylene Oxide Industry Council (now the Ethylene into localized temperatures reaching the EO thermal Oxide/Ethylene Glycols Panel), sponsored work decomposition temperature. The result was an to revisit earlier Union Carbide data and to obtain explosion that destroyed the distillation column [42]. specific information in two areas: (1) decomposition A similar incident occurred at a Gulf Coast EO flame speeds and the extent of flame propagation manufacturing facility in 2000 [43], resulting in in long lengths of 2-inch diameter pipe containing internal column damage. pure EO vapor; and (2) maximum flame speeds in Reference 42 provides the following information long lengths of 12-inch pipe containing pure EO with regard to this type of reaction: vapor. “The disproportionation of ethylene oxide … was This work was completed and results published in previously unknown… and not reported in the 2001[47]. The study showed: open literature. It consists of several simultaneous • Indefinite propagation of a slow deflagration reduction/oxidation reactions…. All three of the flame can occur in 2-inch pipe under certain stoichiometric reactions … below were observed handling conditions. Flames may fail to experimentally.”

propagate under adverse flow conditions or 4 EO 3 C2H4 + 2CO2 + 2H2 if the flame is forced to propagate downward; 5 EO 4 C2H4 + 2CO2 + H2O + H2 however, 2-inch pipe cannot be considered a 6 EO 5 C H + 2CO + 2H O barrier to indefinite flame propagation. 2 4 2 2 The disproportionation produces ethylene and A decomposition flame can accelerate from • carbon dioxide, which reduces the vapor-phase EO a deflagration to a detonation in 12-inch concentration. As the reference notes, “In order pipe. Results of the study observed the for a propagating decomposition of ethylene oxide decomposition flame velocity to have exceeded to occur, the hot spot temperature must reach the 3900 ft/sec (1200 meters/sec), but the authors ethylene oxide autodecomposition temperature of noted that, due to study limitations, the about 500°C (932°F) while the vapor phase contains flame front velocity was likely to have been above about 40% EO.” substantially higher at the far end of the pipe. As the reference points out, the disproportionation The transition from deflagration to detonation reactions have higher activation energies than has the potential to create significantly higher polymerization. Although disproportionation pressures than if a direct detonation occurred. reactions release approximately the same heat as the polymerization reaction, the disproportionation Ethylene Oxide reaction rates are much faster at higher Disproportionation Reactions temperatures. The heat release rates are thus Investigation of a major industrial incident that proportionately higher in disproportionation occurred in a North American EO manufacturing reactions and this mechanism can form a localized facility during the 1990s indicated that EO vapor hot spot:

“... heat release profiles from the reaction of ethylene neutral pH water, can assist in sizing pressure relief

oxide with the gamma form (Fe2O3) of iron oxide devices for inadvertent water contamination of [differ] at … different temperatures. At 155°C (311°F), vessels containing EO. EO polymerization occurs, but it occurs over a period of hours so that the maximum heat flow is relatively Polymerization low. At 200°C (392°F), however, EO disproportionation EO has a tendency to polymerize. As this section occurs in minutes, rapidly generating a very high heating rate. In essence, these disproportionation will discuss, formation of EO polymer is a function reactions can serve as a chemical ignition source of temperature, time at temperature and exposure by generating a hot spot within/on the iron oxide to catalysts or contaminants. containing polymer with a temperature greater than A number of sources have observed thermally driven the EO autodecomposition temperature.” polymerization initiated at different temperatures. The reference concludes: Industrial laboratory tests have shown high purity EO “… Small amounts of ethylene oxide polymers are self-polymerization to have occurred at temperatures indigenous to ethylene oxide liquid operations. at 320°F (160°C) in a closed and near-adiabatic Furthermore, it was found that ethylene oxide system. Additionally, there have been reports that polymer binds any metal ions present in the liquid. thermal initiation of polymerization can occur at The key to safe ORS (Oxide Refining Still) operation temperatures as low as 212° F (100°C). Polymerization is to always maintain adequate liquid contact at all can occur at lower temperatures, including ambient heated surfaces, eliminating the possibility of vapor temperature (see discussion about catalyzation reaching temperatures higher than the boiling point by rust at ambient temperature, below), but at of the equilibrium liquid.” ambient temperature the polymerization reaction is considerably slower. The polymerization reaction Reactions with Water, Acids, and Bases can also be influenced by contaminants for which The reaction of EO with water (i.e., hydrolysis) to the initiation point for polymerization appears to be produce high molecular weight glycols is widely strongly dependent upon the level and type of trace practiced within chemical process industries. impurities in the EO. Hydrolysis of EO to higher molecular weight glycols The polymerization reaction is exothermic, is also used in the design of EO vent scrubbers releasing 1,000 BTU per pound of EO reacted [13]. where EO absorbed by water is reacted to glycols. If exposed to water at temperatures greater than Reactions of this type are exothermic and require 122°F (50°C), the polymer reacts to produce sticky appropriately sized heat removal equipment. polyethylene glycols. Adding or mixing water to EO inventories in storage vessels or transportation containers has potentially The usual catalysts for EO reactions, such as severe consequences. strong alkali [18], iron oxide (rust) [19], and other metal oxides accelerate the reaction. When Rate expressions for EO in water at neutral pH, catalyzed by rust at ambient temperature, acid catalyzed and base catalyzed reactions are polymerization can create blockages or plugs in available in the open literature [9, 51, 52, 53, 54]. operations, such as pluggage of lines, relief valve These studies are generally based on first order inlets, and instrumentation taps. Polymerization kinetics with 5 wt.% EO in the solution. However, can also result in off-specification product. calculated results from these rate expressions Britton [17] has reported a rust catalyzed heat of do not agree well with experimental data at polymerization of 1102 ± 121 BTU/lb. significantly higher EO concentrations. The condition of metal surfaces is extremely Studies designed to better explain kinetics for important in determining the rate of EO polymer the reaction of EO with water at neutral pH were formation. It has been reported [19] that even clean initiated by EO producers [46]. These studies carbon steel catalyzes polymerization, although examined varying EO concentrations (up to 99%) in at a much slower rate than rusty steel. For this water. The data presented, regarding the kinetics, reason, stainless steel is often chosen as a material heat of reaction, stoichiometry, physical properties of construction, especially when the surface to and vapor-liquid equilibrium for various water- volume ratio is high. Some other factors that have contamination reactions of EO and essentially

been observed to affect the rate of polymerization precipitates inside a storage container will tend to are: collect on the bottom. • Metal surface to volume ratio Solubility of EO polymer in various solvents, • Temperature including EO, is a function of molecular weight of the polymer and temperature. In general, higher • Residence time in equipment molecular weight polymer is harder to dissolve. The polymerization reaction has not been found Solubilities of low molecular weight EO polymer in to be auto-catalytic [43]. That is, the presence various solvents are set out in Table 2.5. Note the of a pure EO polymer does not accelerate the extremely low solubility in the non-polar solvent polymerization process. However, polymer heptane. traps iron oxide particles which is a catalyst for Polymer samples from EO processing and storage polymerization. equipment have exhibited molecular weights Overheating of EO or contamination of EO ranging from a few thousand to over one million with catalysts such as potassium hydroxide atomic mass units (amu). At the upper end of this (KOH) can lead to runaway polymerization. range, the polymer is quite insoluble in solvents Reference [18] discusses an EO polymerization and hot water and must be removed by physical (or “polycondensation”) incident involving means. contamination of an EO-containing cylinder with chlorine and alkali. The result was an 8-hour Cold Temperature Polymer Precipitation accelerating or “runaway” reaction that ended (“Drop-Out”) in an explosion. There have been reports observing copious amounts of polymer during railcar off-loading in Table 2.4 Physical Properties of Ethylene cold climates at temperatures between 20°F - 40°F Oxide Polymer [44] (-7°C - 4°C), but when these railcars have been returned to warmer climate loading facilities, the Molecular Melting Temp.°F Density polymer is no longer observed. To explore this Weight (°C) (g/cc) phenomenon further, an EO producer collected

200 -85 softening (65) 1.127 polymer residues from customer sites and plant storage vessels and dissolved the residues in EO. 600 72 softening (22) As illustrated in Figure 2.5 below, rapid cooling of the samples, with molecular weights ranging from 1000 102 (39) 50,000-1,000,000, produced an instantaneous 3400 131 (55) 1.204 dropout temperature that correlated with molecular weight. 10,000 145 (63) Three important observations can be made about 100,000 150 (66) 1.130 the polymer drop-out process. 4,000,000 150 (66) • First, the polymer fell out as a gel with a volume one hundred times larger than the dry polymer originally placed in the vessel. Thus, reports Properties of EO Polymer of copious amounts of polymer appear to be explainable by gel formation. Pure EO polymers have been characterized [44] as clear viscous liquids (molecular weight less than • Second, the polymer rapidly sank to the bottom 600) and as opaque white solids (higher molecular upon standing. Therefore, the concentrated weight). However, in industrial settings, EO polymer and gelled polymer would be expected to be is often dark brown or black, due to the presence observed at the beginning of the off-loading process. of magnetite iron oxide (Fe3O4) inside the polymer matrix. Note that the density of EO polymer is significantly higher than that of EO, so polymer that

Table 2.5 Solubility* of Ethylene Oxide Polymer in Various Solvents [45]

Solvent Mol Wt 500 – 600 Mol Wt 3000 - 3700

T=68°F T=122°F T=68°F T=122°F

Water 73 97 62 84

Methanol 48 96 35 S

Acetone 20 S <1 S

Trichloroethylene 50 90 30 80

Heptane 0.5 .01 <.01 <.01

*Solubility is given in weight percent; S signifies completely soluble

• Third, the temperatures at which the polymer of the EO in a railcar shipped to a colder climate precipitated in this experiment were lower would be expected to decrease over several days than the off-loading temperatures of 20°F to in such conditions, it may be expected for the 40°F (-7°C to 4°C) where polymer has been once-soluble polymer to precipitate out of solution. observed. This analysis helps explain the polymer drop-out Comparison of “long-term” drop-out temperatures phenomenon observed at off-loading temperatures to “instantaneous” ones appears to resolve the of 20°F to 40°F (-7°C to 4°C). discrepancy of the third observation. Figure 2.6 Low molecular weight polymer of 45,000 amu, shows that, after about four days exposure to however, failed to drop out after three weeks 40°F (4°C), most polymers above 180,000 amu at 40°F (4°C). It appears that there is a region precipitate. It is not uncommon for a railcar below 180,000 amu where polymer would not be shipped to a colder destination to sit for several expected to drop out of solution at 40°F (4°C) days before unloading. Since the temperature during routine railcar holding times.

Figure 2.2.55 Ethylene Oxide PolymerPolymer InstantaneousInstantaneous Drop-Out Drop-Out Temperatures Temperatures [46]

Instantaneous Drop-Out Temperatures

Temperature, ° F -10

-20 0 200 400 600 800 1000 1200

Molecular Weight (1000s)

Figure 2.62.6 EthyleneEthylene OxideOxide Polymer Drop-Out TemperaturesTemperatures afterafter 44 DaysDays [47]

Instantaneous vs 4-Day Drop-Out Temperatures

20 Temperature, ° F 0

-20 0 500 1000 Molecular Weight (1000s) Instantaneous 4 Days

2.4 Commercial Chemistry polyether polymers, which are sometimes called poly-oxyethylene-glycols. The molecular weight EO is a highly versatile molecule. Considerable distribution of the polymers depends on the energy is stored in the ring structure of the EO reaction conditions, the catalysts employed, and the molecule. Its reactions proceed mainly via ring ratio of reactants. opening and are highly exothermic. Only a few of the large number of possible reactions are briefly This type of reaction is commercially important discussed here. More detailed information can be because the reaction of EO with water produces found in references [8]-[14]. ethylene glycols. The production of poly(ethylene) glycols by this route is also of commercial Addition to Compounds with a importance. Reactive Hydrogen Atom When used with starting materials other than EO reacts with compounds containing a reactive water (e.g., phenols, ammonia, fatty amines, fatty hydrogen atom to form a product containing a alcohols and fatty acids), the resulting reaction, hydroxyethyl group. Examples of compounds with often referred to as ethoxylation, is used to produce

a reactive hydrogen atom (XH) include: HOH, H2NH, the bulk of the other commercially important EO

HRNH, R2NH, RCOOH, RCONH2, HSH, RSH. ROH, derivatives.

N=CH, and B2H6 (R= alkyl or aryl). The reaction is accelerated by acids and bases. All common acids Addition to Double Bonds and Lewis acids as well as zeolites, ion exchangers EO can add to compounds with double bonds, [29], and aluminum oxide are effective catalysts. A such as carbon dioxide, to form cyclic products. detailed discussion of reaction mechanisms and EO also adds to other double bond systems, e.g., to chemistry can be found in references [12] and [30]. R2C=O, SC=S, O2S=O, RN=CO, and OS=O. The end product of this reaction contains at least one hydroxyl group, so it can react successively Catalytic Isomerization to Acetaldehyde

with additional EO to produce long chain Aluminum oxide (Al2O3), phosphoric acid and phosphates, iron oxides, and, under certain conditions, silver, catalyze the isomerization of EO to acetaldehyde.

Other Reactions • Poly(ethylene) Glycols: Cosmetics, ointments, pharmaceutical preparations, lubricants EO reacts with many other compounds such as (finishing of textiles and ceramics), solvents hydrogen (catalytic reduction to ethanol); hydrogen (paints and drugs) and plasticizers (adhesives sulfide and mercaptans; Grignard reagents; and printing inks). halides; hydrogen cyanide; dimethyl ether; and compounds with active methylene or methyne. • Ethylene Glycol Ethers: Brake fluids, detergents, solvents (paints and lacquers), and extractants

for SO2, H2S, CO2 and mercaptans from natural 2.5 Uses of Ethylene Oxide gas and refinery gas. Products derived from EO have many different • Ethanolamines: Chemicals for textile finishing, uses. Some of these products (or uses) include: cosmetics, soaps, detergents and natural gas • Monoethylene Glycol: Antifreeze for engines, purification. production of polyethylene terephthalate • Ethoxylation products of fatty alcohols, (polyester fibers, film, and bottles), and heat fatty amines, alkyl phenols, cellulose, transfer liquids and deicing of aircraft and poly(propylene glycol): Detergents and runways. surfactants (nonionic), biodegradable • Diethylene Glycol: Polyurethanes, polyesters, detergents, emulsifiers and dispersants. softeners (cork, glue, casein and paper), EO also has direct uses as a sterilizing agent for plasticizers, gas drying and solvents. medical devices and equipment and as a fumigant • Triethylene Glycol: Polyurethanes, lacquers, for spices. In sterilization applications, it is solvents, plasticizers, gas drying and sometimes referred to as EtO. humectants (moisture-retaining agents).

3.0 Health Effects of Ethylene Oxide 3.1 Introduction without significant immediate health effects; however, similar concentrations may cause severe This Chapter provides a brief overview of injury, especially if inhaled for longer periods. information pertaining to potential health hazards associated with exposure to EO. A comprehensive Short-term exposures to EO vapors may cause discussion of health information pertaining to irritation of exposed surfaces, including eyes, skin, EO is beyond the scope of this manual. For more nose, throat and lungs. Irritation of the lungs can information, you may want to contact your supplier. lead to secondary infections, which may lead to Additional health effects information, including pneumonia. Short-term exposures may also affect first aid information, also may be found in your the central nervous system, leading to symptoms supplier’s Material Safety Data Sheet (MSDS). such as drowsiness, disorientation, nausea and vomiting. Convulsions and limb weakness may also The government and other organizations have occur. These symptoms may be expected to reverse established standards and recommendations within a few days after cessation of acute exposure. for personnel exposure to EO [1]. These include the National Institute for Occupational Safety See reference [4] for proposed Acute Exposure and Health (NIOSH), the American Industrial Guidance Levels for EO issued by the National Hygiene Association (AIHA), the National Academy Academy of Sciences committee in September 2006; of Sciences (NAS) in conjunction with the U.S. also see discussion in Section 7.3 regarding IDLH, Environmental Protection Agency (EPA), and the ERPG, and AEGL values and proposed values for EO. Occupational Health and Safety Administration (OSHA). The OSHA standard for EO is located at 3.3 Skin and Eye Contact 29 CFR 1910.1047. It is important to be familiar with these standards and recommendations because Liquid EO can cause freezing of the skin by they set exposure levels that are designed to evaporative cooling. It is also highly irritating be protective of human health. See Chapter 7.0, to the eyes and skin and even dilute solutions Personnel Exposure, for a more detailed discussion can cause blistering or severe damage to the of these topics and contact your supplier for skin or eyes. EO liquid and solutions easily and additional information. rapidly penetrate cloth, leather and some types of rubber, and can produce blistering if clothing or For general information about this topic, users footwear contaminated with EO is not removed. may wish to consult the Concise International See Figure 7.2 in Chapter 7.0 for a photograph of a Chemical Assessment Document (CICAD #54) on chemical burn to feet which resulted from a dilute EO published in 2003 [2]. This document, prepared EO-water mixture permeating leather work boots. by the World Health Organization’s International Programme on Chemical Safety, summarizes sources of EO exposure and potential effects 3.4 Chronic Exposure Hazards on humans and the environment. The CICAD Repeated dermal exposure to EO, or materials notes inhalation to be the route of likely greatest treated with EO, may lead to skin sensitization exposure for human health effects from EO. The (allergic) reactions. Repeated exposure to high CICAD designates cancer as the critical end-point inhalation concentrations may result in respiratory for risk characterization of EO. sensitization (asthmatic) symptoms [5]. A possible association with long term exposure to EO and 3.2 Acute Inhalation Exposure cataract formation has also been reported [3]. EO has a high odor threshold (>250 ppm). Its odor Long-term exposure to EO may also result in threshold is too high to provide an adequate neurological effects similar to those observed in warning of hazardous concentrations. The effects cases of acute short-term exposure. Many of the of inhalation exposure to EO are concentration effects may be non-specific, including headaches, and time dependent. Concentrations of several nausea, lethargy, numbness and memory loss. There hundred ppm may be tolerated for a few minutes may also be a reduced sense of smell and/or taste, and muscle weakness particularly in the legs. The

potential short-term and long-term effects of EO on Table 3.1 Carcinogenicity Classifications 3.0 Health Effects of Ethylene Oxide the nervous system are regarded as reversible. of Ethylene Oxide There have been a few epidemiological reports Organization Classification of increased spontaneous abortions in pregnant hospital or dental sterilizer workers exposed for International Agency for Known Human short times to relatively high EO concentrations Research on Cancer (IARC) Carcinogen [6]. However, methodological questions have Environmental Protection Probable Human raised doubts about the conclusions drawn in Agency (EPA) Carcinogen these studies [7]. Experimental animal studies have shown reproductive effects in rodents exposed to National Toxicology Known Human EO. Effects include a decrease in the number and Program (NTP) Carcinogen weight of offspring in rats exposed to high levels National Institute for Potential of EO. The potential effects of EO on male and Occupational Safety and Occupational female reproduction and development have been Health (NIOSH) Carcinogen the subject of research for many years [6-14] and American Conference on Suspected Human research into this area continues. Contact your Governmental Industrial Carcinogen supplier for additional information. Hygienists (ACGIH) Because EO is reactive, it is capable of directly combining with proteins and DNA when absorbed into the body. EO can react with DNA in tissues Table 3.2 Findings of the NIOSH Ethylene to form various DNA adducts [5, 15, 16]. Ongoing Oxide Studies [24] research is focused on the repair of these DNA adducts and the possible existence of an exposure Summary of the Recent threshold associated with the formation of DNA NIOSH Ethylene Oxide Studies

adducts and associated repair mechanisms. Purpose To determine if exposure to EO is Contact your supplier for additional information. related to cancer or other diseases. The potential for EO to cause cancer, reproductive, Subjects 18,235 men and women exposed to developmental or genetic effects has been EO from 14 sterilizer plants around examined in experiments using laboratory animals the country. Most of these workers and also by studying exposed human worker used EO to sterilize medical supplies populations in epidemiological studies [17-23]. and treat spices. These were the largest studies ever conducted on Based primarily on animal data and on cytogenetic EO exposure and the risk of disease. changes in exposed workers, the International Agency for Research in Cancer (IARC) classified EO Findings No overall elevated risk for any as a known human carcinogen [17]. In 2002, the U.S. type of cancer or other diseases National Toxicology Program classified EO as “known as compared to the general U.S. population. to be a human carcinogen” based on “sufficient evidence of carcinogenicity from studies in humans However, among those workers with very high EO exposures, [18]. In April 2004, NIOSH issued a worker notification (combination of exposure levels bulletin summarizing the results of several recent and years worked); there was human studies [24]. Ongoing research is being evidence of an elevated risk for conducted by numerous investigators, including blood cancers among men and some sponsored by the American Chemistry breast cancers among women. Council’s Ethylene Oxide/Ethylene Glycols Panel, Conclusions Persons exposed to very high to explore the potential for EO to cause cancer. levels of EO may be at an For more information concerning potential chronic increased risk of developing blood hazards from exposure to EO, contact your supplier. cancers among men and breast cancers among women. Examples of cancer classifications established by various governmental entities as of the date of publication of this manual are listed in Table 3.1.

4.0 Environmental Effects of Ethylene Oxide

4.1 Introduction Hydrolysis This Chapter provides a brief overview of Ethylene oxide degrades in both air and natural information pertaining to potential effects of EO to water via radical formation and hydrolysis, leading environmental media. to the formation of glycols and halogenated alcohols (the latter forming in the presence of sodium chloride), which in turn degrade into 4.2 Properties in the Environment simpler molecules such as carbon dioxide and Because it is highly reactive, EO does not persist water. Soil organisms may also convert EO to indefinitely in the atmosphere, soil or water. EO is glycols [30]. characterized by the following properties: Chemical hydrolysis is a major removal process • EO is somewhat persistent in the atmosphere, for EO. At ambient temperatures and in fresh but evidence indicates that it ultimately water, conversion of EO in water to glycols occurs degrades by the process of photolysis; at a slow rate requiring weeks for completion. • EO does not readily absorb into sediments or The rate of EO hydrolysis can be increased by soils and does not persist in soils; if absorbed, either changes in pH and/or temperature. Acidic soil organisms will over time convert EO to conditions, in particular, can have a large positive glycols eliminating any persistence in the soil; effect on hydrolysis rates [7]. The data for EO indicates that water temperature will probably • EO has low to moderate aquatic toxicity; have a greater effect on half-life than expected • EO does not persist in water due to conversion pH differences in natural waters [1]. The hydrolysis to glycol by hydrolysis or degradation of product, ethylene glycol, is biodegraded rapidly in hydrolysis products, by both biotic and abiotic the aquatic environment [8]. processes; Recently developed kinetics for EO hydrolysis • EO does not bioconcentrate in environmental with water predict similar half-lives as seen in media. Figure 4.1 [31].

Table 4.1 Environmentally Relevant Parameters of Ethylene Oxide

Parameter Units Value Reference

Water solubility mg/L miscible [2]

Vapor pressure at 20°C mm Hg 1095 [2]

Atmospheric Boiling Point °C 10.6 [1]

Henry’s Law Constant at 20°C atm-m3/mol 1.4 x 10-4 [1]

Octanol-water partition L/kg -0.30 [3] coefficient (log Kow)

Soil-sediment partition L/kg 1.2 [18] coefficient (log Koc)

Bioconcentration factor (BCF)* L/kg 0.35 [4][5]

Theoretical oxygen demand (ThOD) O2/g EO 1.82 [6]

* Calculated using log BCF = 0.76 log Kow – 0.23 ([4], [5])

Figure 4.14.1 Neutral EO/Water/Glycol KineticsKinetics -- IsothermalIsothermal Case, InitiallyInitially EO/WaterEO/Water mixturemixture

Neutral EO/water/glycol kinetics using model of Melhem et al. Isothermal case, Initially EO/Water mixture 10 5

50% conversion, w EO,0 = 0.001

50% conversion, w EO,0 = 0.05

4 99% conversion, w EO,0 = 0.001 10 99% conversion, w EO,0 = 0.05

10 3

10 2

10 1 Time for reaction, h r

10 0

10 -1 20 40 60 80 100 120 140 160 180 200 220 Temp, F

Figure 4.24.2 Neutral EO/Water/Glycol Kinetics - Adiabatic Case,Case, InitiallyInitially EO/WaterEO/Water

Neutral EO/water/glycol kinetics using model of Melhem et al. Adiabatic case, Initially EO/Water mixture 10 5

50% conv, w EO,0 = 0.001, Trise = 0.44 F 50% conv, w EO,0 = 0.05, Trise = 22.22 F 99% conv, w = 0.001, Trise = 0.88 F 10 4 EO,0 99% conv, w EO,0 = 0.05, Trise = 44.02 F

10 3

10 2

1 Time for reaction, h r 10

10 0

10 -1 20 40 60 80 100 120 140 160 180 200 220 Initial temp, F

The half-life for 1000 ppmw in water at 77°F concentration [14] and its reaction rate with EO, (25°C) is 10 days. Under isothermal conditions, [15] the atmospheric half-life of EO is estimated to 99% conversion is achieved in approximately be 105 days. Under the U.S. Clean Air Act, EO is 70 days. Figure 4.2 shows conversion data for EO classified as a toxic air pollutant and regulated as a in water assuming adiabatic conditions. At very volatile organic compound. low EO concentrations, there is little difference in the half-life assuming isothermal or adiabatic Biodegradation conditions. However, at higher EO concentrations, A series of biodegradation experiments (biological the results may be more significant. Adiabatic oxygen demand tests) have been conducted conditions may be a more reasonable assumption and results are summarized in Table 4.2. These for spill containment tanks. Comparing adiabatic results indicate that EO is rapidly and extensively with isothermal conditions for 5% wt EO in water, biodegraded under aerobic conditions. More rapid the half-life is 6 versus 12 days with a 13°F (-11°C) biodegradation is expected in acclimated systems temperature rise. The time to achieve 99% [16], [17]. Thus, EO will biodegrade in aerobic conversion is 14 versus 76 days with a 25°F (-4°C ) systems such as rivers, lakes and activated sludge temperature rise. units. However, high concentrations of EO may cause inhibition of bacterial respiration in activated Volatilization sludge units. The IC50 (concentration that inhibited Because of its volatility, EO has a tendency to bacterial growth by 50%) in an activated sludge evaporate from water or soil to the air. The Henry’s test (non-acclimated) was in the range of 10- Law Constant is 1.4 x 10-4 atm-m3/mole [1]. It has 100 mg/L [1]. been shown that the transfer rate of EO from In testing of a full-scale chemical plant activated natural waters is about 0.36 times that of oxygen sludge unit, EO was shown to rapidly biodegrade under the same conditions [1]. A 4-hour aeration to non-detectable levels [17]. Measured EO bio test resulted in 100% removal from water [9], and degradation kinetics were determined in this the volatilization half-lives for removal from a model study and were successfully used to predict the river and model lake are 5.9 hours and 3.8 days, measured activated sludge unit EO concentrations respectively [10]. [17].

Persistence in Air Environmental Partitioning Earlier studies suggested that EO is not persistent Environmental partitioning is useful in modeling in air due to washout by rain [1] and degradation by the transport of EO through environmental media. chemical processes [11]. However, more recent work Fugacity modeling evaluates a scenario in which has indicated that EO was not readily deposited a chemical is continuously discharged into one of by rain [12], [13], and the dominant chemical three compartments: air, water, or soil. Following removal process is the reaction with the hydroxyl entry into a single environmental compartment, radical. Based on the most recent determinations chemicals are redistributed as governed by of the average atmospheric hydroxyl radical

Table 4.2 Biological Degradation Data for Ethylene Oxide

Process Results Comments Reference

aerobic 5-d BOD = 20% standard BOD test [9]

10-d BOD = 62%

20-d BOD = 70%

aerobic 5-d BOD = 3% standard BOD test [19]

aerobic 20-d BOD = 52% lightly seeded BOD test [1]

Table 4.3 Aquatic Toxicity Data for Ethylene Oxide*

Species Results Comments Reference

Fathead Maximum safe concentration (96-h) = 41 mg/L no effect concentration [9] minnow

Fathead 96-h LC50 = 57 mg/L static; fresh water [9] minnow

Fathead 24-h LC50 = 86, 90, 274 mg/L static; fresh water [1] minnow 48-h LC50 = 89 mg/L 96-h LC50 = 84 mg/L

Goldfish 24-h LC50 = 90 mg/L static; fresh water [20]

Daphnia magna 24-h LC50 = 260, 270, >300 mg/L static; fresh water [1] 48-h LC50 = 137, 200, 300 mg/L

Brine shrimp 24-h LC50 = 350, 570, >500 mg/L static; salt water [1] 48-h LC50 = 490, >500, 1000 mg/L

* Table includes multiple results from separate tests. compound-specific physical properties, as death for all of the five plant species studied. well as by advection and dispersion. Chemical EO levels in biota have not been reported [18]. concentrations are also simultaneously reduced The bioaccumulation potential is expected to be in the environment by compartment-specific low because of EO’s low octanol/water partition degradation processes. Concentrations in each coefficient. environmental compartment are calculated when advection, inter-media transfers and degradation 4.4 Environmental Evaluation of are at equilibrium. Ethylene Oxide Spills Overall distribution of EO in the environment has The Comprehensive Environmental Response, been characterized in Canada using the ChemCAN Compensation, and Liability Act (CERCLA) Level III fugacity model [18]. The predicted overall reportable quantity for a release of EO to the persistence was estimated at 3 days with 77% environment is 10 pounds. (40 CFR 302.4.) partitioning to air, 23% to water, and less than 1% to soil and sediment. Due to its short overall Soil persistence time, higher EO concentrations were estimated to occur closest to release points. EO is poorly adsorbed to soil. In a spill to soil, much of the EO will be lost to evaporation and the balance will infiltrate the ground. Environmental 4.3 Ecotoxicological Effects considerations include downward penetration of EO aquatic toxicity studies have been conducted EO toward the groundwater table. Some of the EO using fish and crustaceans. The results indicate will convert over time to ethylene glycol through that EO has low to moderate aquatic toxicity hydrolysis; however, this process is relatively slow. (Table 4.3), with toxicity measurements (LC50 in Note that ethylene glycol would biodegrade rapidly acute tests) ranging from 57 to 274 mg/L for fish (0.2 to 0.9 day half-life) [22]. and 137 to 1,000 mg/L for crustaceans. Once the EO has infiltrated the soil, evaporation The effect of EO on the growth and development of will continue but at a reduced rate. Diluting an EO plants has also been investigated. Heck and Pires release with water will increase the viscosity of the [21] reported that atmospheric concentrations of resulting mixture and will have the net effect of 10 ppm showed no effects on plants after seven reducing the speed of downward movement in the days of exposure, but tests conducted at higher soil. If the soil surface is saturated with moisture EO concentrations of up to 1000 ppm in air caused at the time of the release, as might be the case

after a rain, the EO will tend to run off or pond and [27]. The method is designed to be similar to eventually evaporate, hydrolyze or biodegrade. Method TO-15 using evacuated canisters and gas After a spill, the generator of waste must determine chromatography-mass spectrometry (GC-MS). if the material to be disposed of is regulated as Additional information is available from commercial a hazardous waste. Although EO is not a listed vendors specializing in air sampling and analysis. hazardous waste under U.S. environmental regulations, as a pure substance it exhibits the 4.5 Fugitive Emissions characteristic of ignitability (D001). Soils and Fugitive emissions are those that enter the residue from a spill therefore must be analyzed to atmosphere from a source other than a smoke determine if the materials being disposed meet stack, process vent or a storage vessel. Fugitive the criteria for classification as a hazardous waste. emissions include equipment leaks, evaporative Once this determination is made, an appropriate losses from surface impoundments, spills, and disposal technique can be selected in accordance releases from building ventilation systems. EO with federal and state disposal requirements. fugitive emissions are typically calculated rather Water Systems than measured. In some cases, fugitive emissions can be a large contributor to reported emissions. When spilled on water, EO will volatilize and simultaneously spread on the surface of and mix Fugitive emissions are subject to federal with the water. The EO may also simultaneously regulations, but in most states, the primary hydrolyze and biodegrade in bodies of water. EPA implementing regulations are state air quality has developed models to simulate the fate and regulations. State requirements vary; however, transport of chemicals within watershed areas [23]. equipment leaks are typically regulated through These models are publicly available on the Internet. leak detection and repair (LDAR) programs. Federal rules cover the frequency and protocol EO Air Dispersion and Sampling for monitoring valves, connectors, pump seals, compressors and other fugitive emission sources. Chemical releases are typically evaluated using Emissions can be estimated using field leak computer models. EPA developed ALOHA® concentration data (screening data) in EPA- software for evaluating an episodic chemical developed correlation equations [28]. Commercially release and the downwind dispersion of the available software is available to document LDAR chemical cloud [24]. EPA also developed the compliance and estimate fugitive emissions based SCREEN3 air dispersion model for evaluating on screening data. chemicals that disperse as a plume from point, area, flare, and volume sources [25]. Both of these Secondary air emissions from wastewater screening tools are available for free from EPA. systems are another type of fugitive emissions. Several computer models with varying degrees of Other air dispersion modeling software is sophistication have been developed to estimate commercially available. Some of these models may secondary emissions. The publicly available EPA be easier to use than EPA’s models; some may WATER9 software estimates air emissions from offer more modeling options, such as multi-media wastewater collection, storage, treatment and modeling of releases to air, water, or soil. disposal facilities [29]. Proprietary software is also Several methods are available to measure EO in available from commercial vendors. Some modeling ambient air. Real-time field measurements can be issues to consider are how well the modeled made in the 5-10 ppb range using a portable gas emissions agree with field measurements, ability chromatograph with a photoionization detector to simulate complex configurations, the number using NIOSH Method 3702 [26]. Additionally, the of chemicals in the physiochemical property measurement of lower concentrations (below database and the ease of use of the software. 1 ppb) has been validated using EPA Method TO-15 and Summa™ canisters for sampling

5.0 Hazards of Ethylene Oxide

5.1 Introduction Contamination of Ethylene Oxide EO has been involved in incidents in both EO with Aqueous Ammonia production plants and EO consuming plants In a 1962 incident at an EO production and [1] resulting in major plant damage as well as derivatives plant, an EO storage vessel containing fatalities. EO has also been involved in significant 21 tons of EO was contaminated with aqueous transportation incidents. ammonia due to backflow from an ethanolamines One of the best ways for the EO user to understand unit. The EO and ammonia rapidly reacted in the the hazards of EO is to become familiar with vessel; the overpressured vessel ruptured; and an historical incidents. This Chapter reviews some EO vapor cloud explosion occurred. (Figures 5.1, incidents involving EO that are particularly 5.2, 5.3, 5.4, 5.5). The primary explosion threw an instructive in understanding EO hazards. It is hoped adjacent EO storage vessel containing 13 tons that the lessons to be learned from incidents like of EO into another process structure 400 feet these will assist in future plant design as well as away. Numerous vessels in the area of the primary in the development of procedures for operations, explosion ruptured during the vapor cloud maintenance, training and emergency response. explosion or during the resulting fires at the site.

5.2 Contamination Incidents Figure 5.1 Older View of Plant Before Explosion Showing EO Tanks EO is routinely reacted with other chemicals under in Foreground controlled conditions to produce commercial products. Because EO is reactive with so many other chemicals and the resulting reactions are highly exothermic, contamination is one of the most significant hazards of working with EO. Contamination of pure EO with waste materials or other chemicals – including water – can lead to uncontrolled reactions producing large amounts of heat. Generation of heat from the reaction of EO and contaminants or from the polymerization of EO can overpressure and rupture the EO-containing vessel. In a contamination incident, the EO- containing vessel typically ruptures long before all the EO has reacted. The sudden depressurization Figure 5.2 Blast Center after Explosion – when the vessel ruptures results in the formation of EO Vessels No Longer Visible an EO vapor cloud. EO contamination incidents can be described as “kindling chain” events. A typical description of such a chain of events is as follows: a small contamination of an EO vessel leads to a reaction of EO in the vessel, which leads to an overpressure and rupture of the vessel, which leads to formation of an EO vapor cloud, which subsequently results in a vapor cloud explosion. In many of the contamination incidents discussed below, as well as many of the EO decomposition incidents, most of the resulting damage was due to an EO vapor cloud explosion.

Figure 5.3 Aerial View of the Plant Figure 5.4 EO Tank Blown Into Process Showing Overall Damage Structure 400 Feet Away

Ignition of the EO vapor cloud caused extremely heavy structural damage in a radius of 500 feet from the blast center. Implosion damage occurred in a radius of 700 – 1,000 feet from the blast center. Buildings and equipment within a radius of 1,000 feet of the blast center suffered extensive glass breakage and minor structural damage. The explosion could be heard 35 miles away from the plant and evidence of the shock wave from the explosion was noted up to three miles away. The explosion resulted in one fatality, three serious injuries and 18 less serious injuries.

The EO producer’s investigation revealed that rail yard. (Figures 5.6, 5.7, 5.8). The EO producer’s ammonia backflowed from the EO transfer line investigation revealed that a major contributing into the EO storage vessel. The ammonia passed factor to this incident was slow addition of water through several check valves and a positive to the railcar, which helped the EO and water – displacement pump (through its relief valve) before which have different densities – resist mixing. The entering the EO vessel [2,3]. EO and water collected in two layers in the railcar, and the formation of these layers meant that Railcar Explosion Due to Reaction there was a large area of interface between high Between Residual Ethylene Oxide concentration EO and high concentration water. and Cleaning Water This resulted in a much higher reaction rate than In this incident, an EO railcar was sent to a would have occurred if the EO and water had been contractor for cleaning prior to maintenance on well mixed. Contaminants in the brackish water the railcar. Unknown to the cleaning contractor, may have also contributed to the high reaction the railcar contained a “heel” of a few thousand rate. The subsequent reaction generated high gallons of EO. The contractor pumped brackish temperature and pressure in the railcar, resulting water into the car and left it in a rail yard in its rupture [4]. overnight. During the night the railcar exploded, causing significant damage to other railcars in the

Figure 5.5 Plant Laboratory After EO Vapor Figure 5.7 Remnants of Railcar Cloud Explosion, 300 Feet Away from Explosion Center

Figure 5.8 Damage to Other Railcars from Ethylene Oxide Railcar Explosion Figure 5.6 Remnants of Railcar

Ethylene Oxide Railcar Contamination plant thought the car contained anhydrous with Bentonite Clay ammonia. They attempted to offload the EO into an anhydrous ammonia vessel. The ammonia A railcar was returned to an EO producer’s plant vessel was at a significantly higher pressure than after cleaning by a contractor. The contractor the pressure on the EO railcar. During the attempt had put bentonite clay (a drying agent) in the car to offload the EO, a check valve leaked and to reduce rust formation. The EO producer was allowed a small amount of ammonia to backflow unaware of the use of clay and did not remove it into the EO railcar. When the workers at the plant when the railcar was received at the plant. During discovered that the car was delivered by mistake, loading of the railcar with EO, a fire occurred in the unloading operation was stopped and the the railcar dome. Reaction between the bentonite car containing the contaminated EO was sent to clay and EO caused an internal ignition and release its proper destination, 300 kilometers (180 miles) of burning EO vapor through the railcar’s safety away. The railcar exploded in the middle of the relief valve. The fire was initially extinguished with night on a rail siding at the edge of the plant. water but it re-flashed. The fire was ultimately The explosion destroyed an adjacent warehouse, extinguished with dry chemical. caused major damage over a 300 meter radius and Contamination of Railcar with Ammonia broke windows up to 5 kilometers (3 miles) away. (Figure 5.9). A European EO producer shipped an EO railcar to a customer. The railcar was delivered to the wrong plant and the workers at the receiving

Explosion of Railcar Containing EO and water [5]. For more information on EO-water Ethylene Oxide Washwater mixtures, see Chapter 2. In an incident occurring in December 1973, an EO Contamination of Ethylene Oxide Plant producer in the U.S. washed an EO ship loading Nitrogen Source with EO line and an EO storage sphere with river water and then stored the EO contaminated water in a 22,500 This incident involves a European EO plant, in gallon railcar. The railcar contained 8000 gallons of which vessels were padded with 5-bar nitrogen EO at 43°F (6°C) and 5200 gallons of wash water at from a central line. The equipment for feeding 63°F (17°C). The railcar was padded with nitrogen at nitrogen consisted of a check valve and a 35 psig. The railcar was stored on a siding during control valve monitored by a differential pressure which time it was not monitored for temperature measurement. The nitrogen feed equipment was or pressure. After 23 days of storage, the railcar installed on the ground level of the plant, which exploded. Prior to the explosion, the railcar’s relief means that it was below the tops of the vessels. valve lifted, and the immediate area was evacuated. Over time, EO and water (from the EO light ends The exploding railcar created a large fireball and column feed vessel) condensed in the nitrogen a crater in the ground. An adjacent operating line above the control valve. An EO-water mixture facility was demolished. Twenty-eight people had gradually built up directly on the outlet of the minor injuries but there were no fatalities. Based control valve, on the lower pressure side. Every on the damage to the adjacent operating facility, time the control valve opened, the hydrostatic the immediate evacuation most likely prevented a head forced a small amount of liquid EO and water significant number of fatalities. to the upstream side of the control valve. The nitrogen header became contaminated with liquid As illustrated by the incident above, storage of EO/ EO, EO vapor and water. water mixtures can present significant hazards. Storage of EO/water mixtures in railcars, vessels or Nitrogen from this header was used to purge the process equipment should only be practiced with a EO unit oxygen feed line during a unit shutdown. thorough understanding of the reaction kinetics of During the purge, there was a reverse flow

Figure 5.9 Remnants of Railcar (after EO explosion caused by contamination with ammonia)

from the oxygen line into the nitrogen line. An 5.4 Ethylene Oxide explosion between EO and oxygen occurred in the Decomposition Incidents nitrogen line and a piece of shrapnel from the line EO decomposes at a temperature around 932°F penetrated the adjacent ethylene line, releasing (500°C). The incidents listed below illustrate ethylene into the pump house. The ethylene release decomposition incidents. resulted in a second, much larger explosion that blew the door off and caused major damage to the Ethylene Oxide Decomposition Incidents pump house. and External Fires An external fire is one of the most hazardous 5.3 Formation of Ethylene Oxide situations that can occur in an EO plant because Vapor Clouds of the potential for EO decomposition. Even with Release of EO vapors can result in the formation water spray systems and well-insulated equipment, of a vapor cloud. Because the minimum ignition flame impingement from an external fire can energy of EO in air is extremely low, EO vapor increase piping and vessel wall temperatures to EO clouds often explode. (See Chapter 2 for more decomposition temperature in a short time period. information on EO vapor ignition energy.) Note If this happens, an internal explosion can occur. that in most EO contamination incidents and EO decomposition incidents, the majority of the Fire Around Distillation Column damage has resulted from an EO vapor cloud An EO producer in the U.S. had a rupture of an EO explosion. Such incidents can be extremely compressor cylinder. This resulted in a large fire, destructive. which engulfed the EO distillation column. The resulting temperature increase on the surface of Ethoxylation Plant Explosion the column and in the contained EO resulted in an The contents of an ethoxylation reactor were internal explosion and significant damage. pumped to a neutralization vessel about one half- hour before completion of all the reaction steps. Flange Fire while Plant was Down The neutralization vessel was located indoors. The A European EO producer experienced a flange material was pumped to the vessel at a temperature leak in the EO distillation section of an EO plant. of approximately 390°F (199°C). The vessel The plant had been shut down but still contained contained 100 to 150 pounds of un-reacted EO. The an inventory of EO. The flange leak resulted EO rapidly vaporized and escaped from the vessel, in a fire and the flame impinged on a process mixing with the air in the building. An explosion line containing EO. The heat caused an EO occurred when an operator entered the building to decomposition reaction to be initiated in the line. turn on the ventilation system. The explosion killed The decomposition propagated down the line and the operator entering the building, injured two other into a distillation column. The column head was operators and destroyed the building housing the torn off and thrown about 100 feet. Large and small ethoxylation reactor and the neutralization vessel. parts of the column jacket were scattered over a Nearby buildings sustained extensive damage. 2000 foot radius. Only 7 minutes elapsed from the start of the unit fire to the column explosion.

Pump Seal Leak Fire A European EO production plant had an EO pump seal leak that was ignited by contact with hot pump parts. The flame from the pump seal fire impinged on an uninsulated minimum flow return line causing evaporation of the EO in that line. Continued heat input from the flame impingement resulted in an EO decomposition in the minimum flow line. The decomposition reaction propagated into the EO

purification column reflux drum where an explosion kept cleared of EO, pressured up with 200-psig occurred. The reflux drum and its associated nitrogen, and left with the suction and double distillation column were destroyed. This incident discharge valves blocked in. A small amount of EO resulted in four fatalities. The plant was heavily leaked through the two blocked discharge valves damaged and out of operation for four months. into the pump. An electrical system malfunction caused the high-speed centrifugal pump’s electric Ethylene Oxide Decomposition Incidents motor to start. The pump ran blocked in for and Mechanical Equipment approximately ten minutes until the seal area of the Some important considerations regarding pumps pump reached EO decomposition temperature and and compressors in EO service include the the pump exploded. The decomposition of the 0.6 potential for high temperatures if mechanical pounds of EO in the bowl of the pump generated energy is not dissipated and the potential for a fire over 450,000 pounds of force and caused the due to seal leaks. A good example of nondissipated failure of twelve, ¾ inch stainless steel nuts and mechanical energy is a blocked pump discharge. bolts that held the pump together (Figure 5.10). The The pump seal leak fire described immediately upper part of the vertical centrifugal pump and the above is a good example of the potential motor (approximately 1000 pounds) were launched consequences of a seal leak fire. The two incidents 60 feet in the air. The pump and motor landed on described in this section illustrate potential results the discharge piping of another EO feed pump that of operating an EO pump deadheaded. was operating at 750 psig, pumping 80 gpm of EO (Figure 5.11). The discharge piping did not fail. Decomposition in Reflux Pump Propagates to Reflux Drum and Tower Ethylene Oxide Decomposition in Blocked-in Pump The EO purification column reflux pump of a European EO producer had been over-speeding. A U.S. EO producer uses magnetic drive pumps The producer had also been experiencing extensively in EO service. At the time of this instrumentation problems with the level controller incident, the magnetic drive pumps were protected on the reflux drum, which caused the reflux control from overheating by a safety shutdown system valve on the discharge of the reflux pump to fail that included shutdown initiators for both high while closed. There was no minimum flow recycle temperature and low flow. During the normal or high temperature or low flow safety shutdown startup sequence for these pumps, the shutdown system on the reflux pump. (For more information system must be bypassed for a few seconds to about safety systems on EO pumps, see section allow the low flow shutdown to be satisfied. To 6.7) The reflux pump operated deadheaded against allow the pump to start, the pump start switch was the level control valve, causing the temperature also configured to function as a shutdown system in the pump to rise. The EO vaporized and the bypass switch while it was depressed. During a EO vapor was heated to its decomposition normal startup of these pumps, the operator had to temperature. The EO in the pump decomposed hold the start switch down for a couple of seconds and the decomposition propagated through the to allow the pump to start pumping and satisfy the pump suction line into the reflux vessel where low flow shutdown. an explosion occurred. Shortly afterward the EO On the day this incident occurred, an EO tower purification column exploded. This explosion residue pump had been tripping every few resulted in four fatalities. The plant was heavily minutes. An operator tried to start the spare pump, damaged and out of operation for four months [6]. but it would not run. The operator then attempted to re-start the pump that had tripped. The operator Ethylene Oxide Decomposition in tried several times, but each time it tripped. In an Blocked-in Pump attempt to keep the EO production unit running, A U.S. EO producer used high-speed centrifugal the operator held the start button down for several pumps to feed EO to two ethylene glycol units. minutes to keep the pump running without tripping. The plant had a common spare feed pump for the After several minutes of holding the start button two glycol units. The spare pump was typically down, the operator noticed that the pump had

become very hot and there was a grinding sound decomposition; under EO decomposition conditions, from the back of the pump. The operator released the methane produced in the decomposition can the start button. The EO production unit was shut decompose further to form carbon and hydrogen). down and the pump was pulled out for repair. The containment can had a blue discoloration that When the pump was opened up for repair, the area indicated that it had been exposed to temperatures between the driven magnet and the containment over 800°F (426°C). EO had decomposed inside the can was completely packed full of carbon (carbon containment can and around the driven magnet [7]. deposits are sometimes found after an EO In this incident, it is believed that the decomposition reaction did not propagate through the small passages inside the pump because the mass of the metal in the pump absorbed enough heat to Figure 5.10 High Speed Centrifugal Pump quench the decomposition flame. “Launched” by Decomposition of 0.6 Pounds of Ethylene Oxide Ethylene Oxide Decomposition Incidents and Leaks

Under Insulation An EO leak into porous insulation can result in reactions of EO with the insulation material or EO with moisture contained in the insulation, which can lead to high temperatures. This may occur with mineral wool, asbestos, fiberglass, calcium silicate, magnesium silicate and other porous insulation materials. Porous insulation can soak up and retain water from the environment, thereby providing a large surface area for EO-water contact. It has also

Figure 5.11 Motor Landed on Operating Ethylene Oxide Pump Discharge Line

been shown that many types of insulation catalyze increased both the temperature and the pressure reactions of EO [8]. These reactions all produce in the tower until it ruptured. The remaining EO in heat, the dissipation of which is inhibited by the the tower was suddenly released at high pressure insulation itself. An under insulation EO leak can and temperature forming an EO vapor cloud, which result in a “hot spot” on the wall of the vessel, then exploded. The EO vapor cloud explosion which can trigger a decomposition reaction of the caused more damage to the plant than the initial EO inside the vessel. Use of nonporous insulation, decomposition reaction (Figures 5.12, 5.13, 5.14, such as cellular glass, reduces the potential for hot 5.15). spots and still provides a degree of protection from overheating due to fire. See Section 6.3 for a more Ethylene Oxide Leak Under Insulation thorough discussion of insulation. Results in Tower Explosion In 1989, a catastrophic explosion of an EO Ethylene Oxide Leak at an Insulated Manway purification column occurred at the production Flange Results in Tower Explosion plant of a European EO producer. A crack In 1987, a European EO producer had a catastrophic developed where a pipe was attached to the wall explosion of its EO purification column. The of an EO distillation tower. The crack allowed EO damage to the plant was very extensive. to leak into mineral wool insulation. EO reacted Investigation after the incident revealed that a with water in the insulation to produce polyglycols. manway flange leak under mineral wool insulation When portions of the insulation and insulation on the EO distillation column resulted in an external jacketing were removed for maintenance, air flowed “hot spot” which caused an EO decomposition into and under the insulation, rapidly oxidizing the inside the tower. The decomposition reaction polyglycols and producing a high temperature.

Figure 5.12 Ethylene Oxide Distillation Column Reboiler after Explosion

Figure 5.13 Aerial View of Ethylene Oxide Plant after Explosion

Figure 5.14 Remnants of Base of Ethylene Oxide Distillation Column after Explosion

Figure 5.15 Piece of Ethylene Oxide Distillation Column Wall Turned Inside Out by Explosion

The insulation prevented dissipation of the heat [9]. After the incident, the EO producer’s research and the reaction in the insulation caused the identified a previously unknown reaction of EO: wall temperature of the EO distillation tower disproportionation (see discussion in Section 2.3). to reach EO decomposition temperature. The This reaction can be initiated at significantly lower internal decomposition reaction resulted in vessel temperatures than thermal decomposition. In this failure. In this incident, the EO decomposition incident, the reaction occurred reaction initiated in the aldehyde column and • Inside the tubes of a distillation column reboiler; propagated through overhead piping to the EO • purification column, which also exploded. Like In the presence of a deposit of high surface the incident in 1987, most of the damage to the area rust embedded in an EO polymer matrix; plant in this incident was caused by the EO and vapor cloud explosion. Damage to the plant was • During a period when flow through the reboiler severe, requiring more than a year for rebuilding was reduced by a process upset resulting in (Figures 5.16, 5.17, 5.18). tube surfaces exposed to vapor only, not liquid. It was concluded that loss of reboiler circulation Ethylene Oxide Decomposition – allowed for rapid heat buildup in the vicinity of the Ethylene Oxide Disproportionation Reaction iron oxide/polymer deposit, resulting in localized in Column Vertical Thermosiphon Reboiler EO vapor temperatures reaching the thermal Ethylene Oxide Redistillation decomposition temperature. The result was an Column Explosion explosion that destroyed the distillation column. An EO manufacturer experienced an explosion in Ethylene Oxide Decomposition – an EO redistillation column (Figures 5.19, 5.20). The Ethylene Oxide Disproportionation Reaction explosion appeared to have been initiated at the in a Horizontal Thermosiphon Reboiler top of the reboiler. There was one fatality and the This June 2000 redistillation column incident plant was out of service for more than one year

Figure 5.16 Aerial View of EO Unit After Explosion

Figure 5.17 EO Plant Burning after Explosion

Figure 5.18 EO Purification After Explosion – Two Towers are Missing

occurred on the shell side of a horizontal • There was inadvertent heat input to the reboiler thermosiphon reboiler. Damage was limited to the during startup; trays in the column and some associated piping. • The initial charging of EO to the column during There was no loss of containment and there were startup was interrupted, exposing the reboiler no injuries or fatalities. The incident occurred tube bundle to EO vapor; during the startup of the unit and when the • following conditions were present: An iron oxide-polymer deposit was present on the reboiler tubes which initiated the disproportionation reaction. Figure 5.19 Ethylene Oxide Re-distillation Tower Explosion (re-distillation tower is gone and adjacent tower is damaged and leaning) Figure 5.20 Resulting Damage to the Plant

The iron oxide-polymer deposit was wetted and 5.5 Ethylene Oxide dried during the startup with the interruption Transportation Incidents of feed to the column. A rapid temperature rise In both of the following transportation incidents an initiated the disproportionation reaction, which in EO railcar was punctured and a fire resulted. In one turn led to an EO vapor decomposition reaction. incident, the emergency responders controlled the The decomposition reaction propagated from the process of burning off the EO. In the other incident, reboiler into the distillation column. Several of injuries were prevented by evacuation. the bottom trays in the column did not have the manways in place. This allowed the velocity of Ethylene Oxide Railcar Fire the reaction front and volume of decomposition gases to accelerate to a critical point up to the In July 1981, a full railcar of EO was punctured as trays which had the manways properly installed. a result of a coupler override (this was before The remaining trays in the top of the column were double shelf couplers were required by federal propelled upward and wedged in the top of the regulations) at a railyard in Newark, New Jersey. tower and the vapor overhead line. The pressure The leaking EO ignited. The location of the railyard wave continued into the column overhead piping was very close to the Newark International Airport damaging several piping supports and several and the New Jersey Turnpike. Both the airport trays in the downstream column. The top trays were and a four mile section of the turnpike were shut forced into the overhead piping of the column. It is down during the incident. Three unmanned fire believed that the trays compacted into the top of monitors were set up to limit the temperature the tower and that overhead piping prevented the increase in the car and to reduce the likelihood decomposition reaction from propagating into the of a “hot spot” in the car shell. Nitrogen was fed downstream equipment. into the car through a hose from portable nitrogen bottles to maintain an inert atmosphere inside the Ethylene Oxide Decomposition – car. With input from EO technical specialists, a Catalyst Residue in the Vapor Space burn pit was set up approximately 400 feet away of an Ethoxylation Reactor from the railcar. Liquid from the railcar was routed to the burn pit and ignited. The contents of the An ethoxylation reactor exploded during normal railcar were burned over a three hour period while operation while EO was being fed to the reactor. the leaking EO continued to burn at the railcar. During the investigation of the explosion, pieces A 1½ inch firewater hose was also connected to of the reactor head were found that had a heavy allow flooding of the car’s interior when the flaring buildup of potassium hydroxide (KOH) catalyst was complete. The fire was allowed to burn until on the metal. The reactor was not designed for all liquid EO had been consumed. When the fire addition of KOH directly into the liquid. The liquid went out, the car was filled with water as rapidly as KOH stream was added at the top of the reactor possible to cool the car and to expel unburned EO and a KOH residue had built up on the inside of vapors. No further damage resulted. the head. The KOH catalyzed a reaction of the EO in the vapor space of the reactor driving the Ethylene Oxide Railcar Explosion temperature in localized areas of the reactor head In October 1969, a multi-car derailment resulted to the decomposition temperature. The vapor in the puncture of an EO railcar and a fire. Water space decomposed explosively. The vapor space was put on the burning railcar and on an adjacent of the reactor was blanketed with nitrogen, but the EO railcar that was not leaking. The fire was nitrogen partial pressure was insufficient to yield extinguished after about 12 hours. About five hours a non-decomposable mixture. Refer to Section 6.6 after the fire was out, the safety relief valve on the for more information on inerting ethoxylation adjacent EO railcar lifted and vapor from the relief reactors. valve caught fire. Comments from responders at the scene indicated that the adjacent car “felt cool” after the initial fire was extinguished. At this point, the accident scene was cleared for a radius of ¼ mile. After about 55 hours, the relief valve fire went out for a brief period and then a violent

explosion occurred. A large piece of the railcar was Figure 5.21 Filter Case after Runaway blown 5,000 feet through the air. The explosion Polymerization was attributed to flame propagation back through the safety relief valve or a “hot spot” in the metal near the relief valve that triggered a decomposition reaction.

5.6 Runaway Ethylene Oxide Polymerization Incidents

Polymerization Incidents in Ethylene Oxide Filters In 1969, a U.S. EO producer had an EO filter explode due to runaway polymerization. The filter had been left full of EO and blocked-in. In May 1998, runaway polymerization occurred in an EO railcar-loading filter of a U.S. EO producer. The insulated loading filter was normally cooled by continuous circulation of chilled EO. However, Figure 5.22 Filter Case after Runaway circulation in this case had been stopped for Polymerization over two days due to maintenance on other equipment in the EO tankfarm. During the incident investigation, it was discovered that the filter elements had not been changed in 18 months and were highly loaded with rust. The person formerly responsible for changing the filter elements had retired and this duty had not been reassigned to another employee. The ambient temperature at the time of the runaway polymerization incident was 100°F (38°C). The combination of the stagnant EO, the high ambient temperature and the rust in the filter elements initiated the polymerization. The filter case did not rupture, but the temperature in the Figure 5.23 Filter Case after Runaway filter case was very high and the pressure was Polymerization high enough to stretch the bolts on the head of the filter case. The cotton filter elements were found to be carbonized (dehydrated), indicating that the temperature in the center of the filter case exceeded 500°F (260°C) (Figures 5.21, 5.22, 5.23).

5.7 Runaway Reactions in Ethoxylation Units

Delayed Addition of Catalyst EO was added to an ethoxylation reactor with the circulation cooling line blocked. The circulation line was also used for addition of a KOH catalyst. In order to continue feeding EO to the reactor, the

operator had to reset the high temperature EO incidents caused damage to the plants. Most of feed shutdown. When it was discovered that the the facilities involved used oxidizers to control EO circulation line was blocked, the block valve was emissions. In April 2000, in response to these opened to re-establish cooling, but this action explosions, the National Institute for Occupational allowed a “slug” of concentrated KOH to enter the Safety and Health (NIOSH) published a Safety reactor and come into contact with EO. Because Alert titled “Preventing Worker Injuries and Deaths catalyst was not present when EO feed was from Explosions in Industrial Ethylene Oxide started, the EO concentration exceeded normal Sterilization Facilities.” [10] EPA and Industry design levels. The sudden addition of catalyst representatives from the Ethylene Oxide Sterlizers when the cooling line was opened resulted in Association (EOSA) collaborated with NIOSH to a runaway reaction. Subsequently, the reactor produce this alert. It warns EO sterilization facility ruptured explosively. Metal parts and valves employees and managers about the explosion were propelled over a distance of approximately hazards associated with oxidizers, and it makes 2,300 feet. comprehensive recommendations for preventing future incidents. Inadvertent Addition of Reactive Material During 1997 and 1998, there were explosions and (Hydrogen Peroxide) fires at four large-scale sterilization plants that use The reactor in a European ethoxylation unit EO to sterilize medical devices. There was another suddenly exploded. The incident investigation explosion at large-scale sterilization plant in 2004. revealed that hydrogen peroxide used to bleach The explosion in 2004 was investigated by the U.S. the ethoxylate product was inadvertently added Chemical Safety and Hazard Investigation Boar during the EO addition phase of the operation. The (CSB). The CSB produced a report and video on EO reacted with the hydrogen peroxide and caused the 2004 explosion, which is available to the public the reactor to explode. There was no interlock to on the CSB website, www.csb.gov.[11] prevent addition of hydrogen peroxide when EO All of the sterilizer explosions in 1997, 1998 was present in the reactor. and 2004 were associated with EO abatement devices used for destruction of EO in process 5.8 Incidents in Ethylene Oxide vents. Four of the explosions involved catalytic Abatement Devices oxidizers and one explosion involved a thermal oxidizers. Each of the explosions either severely Catalytic and Thermal Oxidizer Incidents damaged or destroyed the EO abatement device Between 1994 and 1998, EO was involved in 10 and the sterilization chambers. Figure 5.24 is an explosions at industrial EO sterilization facilities overview diagram of the 2004 explosion. Figure and EO repackaging plants. One of these 5.25 through 5.27 are photos of damage to the incidents resulted in a fatality and all of the sterilization plant. [11]

Figure 5.24 Diagram of Sterilizer Explosion

Two of the sterilizer incidents occurred during the Figure 5.25 Sterilizer Explosion Damage startup testing of catalytic oxidizers. In one of the incidents, there was an explosion with a fireball and the oxidizer system and the building were destroyed. In the 2004 explosion, the doors were blown off of the sterilization chamber and the walls of the chamber itself were bulged outward. [11] Three common themes in all of these EO abatement device incidents were: (1) the lack of an interlock to prevent opening the chamber door when EO was in the chamber or the ability for the operator to override an interlock, (2) a higher than design concentration of EO at the inlet of the EO abatement device, and (3) the lack of EO concentration monitoring in the sterilization chamber to warn of explosive concentrations. Catalytic oxidizers are designed for conversion of low concentrations of EO in a vent stream to carbon dioxide and water. When the vent system Figure 5.26 Sterilization Chamber Damage to a catalytic oxidizer has a higher then design EO concentration, the result can be overheating of the catalyst bed and uncontrolled combustion or decomposition of the excess EO due to the high temperature in the catalyst bed.

Overload of Reactive Vent Scrubber Incidents have also occurred in acid or caustic reactive EO vent scrubbers when a higher than design EO concentration was sent to the scrubber. Sending liquid EO to a reactive vent scrubber can easily overload a scrubber. Reactive vent scrubbers are typically designed to handle low concentrations of EO in a gaseous vent stream. Reactive vent scrubber systems are often designed with acid or caustic recirculation systems. If liquid EO is fed into the bottom of a reactive vent scrubber, it can flow into the acid or caustic vessel and result in a Figure 5.27 Damage to the building wall from runaway reaction and explosion. impact of sterilizer door In the early 1990s, operators at an ethoxylates production unit with a sulfuric acid scrubber tried to clear the unit’s EO feed line by blowing the liquid EO to the vent scrubber with nitrogen. The liquid EO overloaded the vent scrubber, resulting in a runaway EO hydrolysis reaction in the scrubber. The polypropylene packing in the scrubber melted and the 40 foot tall fiberglass reinforced plastic (FRP) scrubber tower failed and collapsed due to the high temperature produced by the EO hydrolysis in the scrubber. See Section 6.8 for more information on vents and scrubbers.

6.0 Design of Facilities

6.1 Introduction EO pumps are potential sources of fire hazard; for example, a mechanical seal failure and EO The characteristics of EO – including flammability, release, followed by fire. When locating a pump, toxicity and reactivity – are crucial considerations consider the possible effects of a pump seal fire on in the design of facilities for the storage, transport, surrounding equipment or railcars. Two techniques and processing of this material. This Chapter, which available to help mitigate potential hazards include summarizes some important issues relevant to EO pump installation within a diked or curbed area facility design, addresses not just the chemical and with leaks/spills routed to a secondary containment physical characteristics of EO, but also includes area and pump installation in a separate discussion of the practical experience of industry. containment area from storage vessels. It is particularly helpful to review Chapter 2, Properties of EO, and Chapter 5, Hazards of EO, EO piping is also a potential source of fire hazard. before reading this Chapter. For routing EO piping, some key considerations include: Note that risk assessment and hazard analysis, mandated by OSHA Regulations at 29 CFR 1910.119, • Proximity to utility piping and systems essential are an integral part of the initial design of the to plant safety in the event of an EO fire; facility and must also be conducted before making • Minimizing EO piping through hazardous plant modifications to equipment and procedures. areas; • Minimizing EO piping adjacent to higher 6.2 Plant Layout and Siting temperature lines (>400°F/204°C) where there is This section addresses general considerations for a possibility of heating the EO in the piping; siting of EO storage vessels, pumps and piping. • Minimizing EO piping close to lines containing Some important considerations in selecting the corrosive chemicals that could damage the location of EO storage vessels include: pipe; and • Criteria developed for LPG in NFPA [1], [2], [3] • Protecting grade-level pipe runs from impact and API [4] standards to establish separation damage, especially if piping is adjacent to road distances; and railways. • Distance from operating plants, offices and Routing EO piping underground increases the perimeter fences; possibility of corrosion and makes inspection • Distance (and adequate isolation) from fire more difficult. It may, however, reduce or eliminate hazards and potential ignition sources; the need for insulation, and it may significantly reduce or eliminate potential exposure to fire. • Whether the location is a low fire risk area; For EO piping routed underground, installation of • Accessibility of the vessel to emergency a cathodic protection system which is regularly responders (e.g., is it in an “open” area); maintained will help protect the EO piping from • Intended use of the storage vessel for inventory corrosion. control (e.g., for EO in process feed vessels in Electrical equipment in areas that produce, store, the immediate vicinity of the plant, consider the use, load or unload EO must conform to National minimum quantity of inventory compatible with Electrical Code, Class I, Division 1 or 2, Group the effective control and safe operation of the B (or Group C if conduit seals comply with NEC process concerned); paragraph 501-5(a)). • Potential impacts of a release on the community; and • Site security.

6.3 Materials of Construction that penetrates under insulation. For example, the typical operating temperatures of EO purification Because of the reactivity of EO, materials in contact columns make them particularly vulnerable to with EO must be chosen with care. external corrosion. There have been several Metallic Materials (Metals and Alloys) cases where carbon steel EO purification columns experienced serious external corrosion above Equipment for storage and handling of EO is insulation support rings where water was trapped. generally fabricated from 300 series austenitic External corrosion has also been observed in stainless steels or mild carbon steel. Stainless carbon steel EO storage vessels and piping. steels have the advantage of minimizing the potential for rust, which can catalyze EO Historically, metals such as copper and silver and polymerization. Cast iron is not considered suitable their alloys have not been used in EO service. for EO use due to the low ductility of the material. This was based on the potential for the formation of metal acetylides, which are explosive. The Austenitic stainless steels such as Type 304 current EO production technologies in use in North and Type 316 are typically used for tubing, small America do not result in the formation of acetylene. piping, instrumentation and other equipment that cannot be readily cleaned of rust. Use of austenitic Published literature describing the compatibility stainless steels is also appropriate in areas where of mercury with EO presents an inconsistent view EO liquid or vapor is likely to remain stagnant for concerning hazards that may result from the periods of time. contact of these two substances. Some papers suggest that elemental mercury can promote Note that, depending on location and process and accelerate the decomposition of EO. Others conditions, stainless steels can be subject to suggest that the presence of small, trace quantities stress corrosion cracking from naturally occurring of acetylenes contained in the EO is the source atmospheric chlorides. External coating in such of the hazard (acetylenes react with the mercury circumstances is an appropriate measure to to form explosive mercury acetylides). While the address corrosion potential. literature does not present a consensus view as to When carbon steels are chosen, it is important whether elemental mercury may present a potential that they retain integrity under the full range safety hazard if it comes into contact with EO, of temperatures encountered in the specific limiting the use of mercury in EO service, where application. Also note that the presence of rust appropriate or practicable, may reduce the risk of a (iron oxide, in the form of red hematite or black reactive hazard. magnetite) on internal surfaces of carbon steel equipment leads to polymerization of EO. Non-Metallic Materials Carbon steels are also susceptible to external EO rapidly attacks and degrades many of the corrosion from wet external insulation and wet organic polymers and elastomers that are used to metal surfaces. These conditions can occur from make O-rings, packing material and gaskets. When ingress of rainwater and also by condensation selecting non-metallic materials of construction in of atmospheric moisture on cold metal surfaces contact with EO, it is important to understand the (for example, equipment containing refrigerated rate of degradation of the material. A good starting EO). Use of a suitable coating on the carbon point is to review available test data specific to the steel equipment and periodic monitoring EO service being considered. However, because of the physical integrity of the coating and material degradation may be affected by multiple equipment, can help minimize the risk of complex factors, industry field testing or field corrosion. Monitoring is conducted in accordance experience with the material may also be extremely with the plant’s mechanical integrity program useful in helping to inform the selection. (required under OSHA Regulations at 29 CFR If neither test data nor field experience data is 1910.119). External corrosion is a concern when available to help select a material of construction, the operating temperature of the equipment is consider conducting a field test that includes an below approximately 200°F (93°C) because this analysis of consequence of material failure. If a temperature range is too low to evaporate water field test is used, additional measures to monitor

and evaluate the performance of the material are Asbestos and asbestos-filled materials are not generally implemented, which may include: durable in EO service. Industry experience has • Testing the material in a limited number of shown that asbestos gaskets are attacked by EO applications; and have failed catastrophically without any prior warning. (Figure 6.1) • Testing the material in a type of application where the consequence of a material failure is Polytetrafluoroethylene (PTFE) is chemically minimized (for example, testing only the inboard resistant to EO at temperatures as high as 400 - seal on a double mechanical seal); 500°F (204 - 260°C). Virgin (non-filled) PTFE, exhibits cold flow behavior at all temperatures and • Increasing the frequency of monitoring for EO does not work well as a gasket material in most leaks; and conventional applications. Several EO operations • Increasing the frequency of inspection of the have experienced cold flow incidents with virgin material being tested. PTFE (non-filled) gaskets resulting in EO releases. (Figure 6.2) At least one of these incidents was Gaskets followed by ignition and significant damage to the Design criteria for gaskets include materials of facility. In well-confined applications (such as valve construction, gasket thickness and torque. There packing and tongue and groove joints), virgin PTFE may be other gasket design criteria relevant to can be used successfully. the specific joint. Once a facility specifies the Because of its tendency to cold flow, PTFE gasket(s) to be used in EO service, it is useful for gasket applications is typically filled with to adopt a process or system to check that the glass fibers or ceramic particles to increase its specified gasket(s) are actually in use. There have dimensional stability. Glass and ceramic filled PTFE been cases in the industry where one gasket was may absorb EO. If this occurs, the EO polymerizes specified but a different gasket was inadvertently within the PTFE-filler matrix and the resulting EO installed, resulting in an EO leak.

Figure 6.1 Degradation of Compressed Asbestos Valve Bonnet Gaskets by Ethylene Oxide

Figure 6.2 PTFE Gasket Failures in EO Service Due to Cold Flow

polymer causes swelling and failure of the gasket. Figure 6.3 Glass Filled PTFE Gasket Failure Glass and ceramic filled PTFE gaskets have failed Due to EO Polymerization in in many applications in EO service, especially at PTFE-Glass Matrix higher temperatures (Figure 6.3) Spiral wound gaskets with stainless steel windings and virgin PTFE or graphite filler have been successfully used to seal raised face flanges and valve bonnets in EO service. However, there have also been many incidents where EO permeated between the windings and the filler material and polymerized. If EO permeates this space, EO polymer can swell and generate enough force to cause deformation or unwinding of the gasket (Figure 6.4). Inner and outer retaining rings will help Figure 6.4a Deformation of a Spiral Wound avoid unwinding of the spiral wound gasket in the Stainless Steel-PTFE Gasket event that EO polymer forms within the windings. In Due to EO Permeation and isolated instances, polymer formation may deform Polymerization the gasket windings even with inner and outer retaining rings (Figure 6.4, 6.4a) When installing spiral wound gaskets, compressing the gasket evenly will help reduce the possibility of gasket failure due to EO permeating between the windings and filler. Proper gasket placement, flange alignment and torquing procedures have been used effectively to achieve even compression. High purity (98% or higher), flexible compressed graphite is a commonly used gasket and packing material in EO service. This material has no fillers or binders and is chemically compatible for use with EO. High purity, flexible compressed graphite is available in flat sheet form as well as crinkled tape for valve packing. The sheet form of flexible graphite is somewhat fragile, so for gasket applications the sheet is typically used as filler for stainless steel spiral wound gaskets. (Figure 6.5) Figure 6.4b Deformation of a Spiral In EO service applications where spiral wound Wound Stainless Steel-PTFE Gasket gaskets cannot be used, laminated flexible compressed graphite gaskets are often used. Several manufacturers produce gaskets from two layers of flexible compressed graphite laminated to a 0.004” tang (perforated) stainless steel sheet. Because the graphite is laminated to tang stainless steel sheet, there are no adhesives used in the lamination process. (Figures 6.7 and 6.8) If a laminated gasket is used, it is important to specify a tang stainless steel sheet rather than flat stainless steel sheet. Tests have shown that EO will attack some adhesives that are used to bond flexible graphite to flat stainless steel sheet (Figure 6.8).

Figure 6.5 Spiral Wound Gasket with Figure 6.6 Laminated Gasket Made of Stainless Steel Windings, Flexible Polycarbon Sigraflex™ BTCSS Compressed Graphite Filler, and Flexible Compressed Graphite Inner and Outer Retaining Rings – Laminated on Stainless Steel Tang Sheet

Figure 6.7 Laminated Gasket Made of UCAR Figure 6.8 Gasket Test Showing Failure of Grafoil GH™ E Flexible Compressed Compressed Graphite Gasket, Graphite – Laminated on Stainless Laminated on Flat Stainless Steel Steel Tang Sheet Sheet with an Adhesive

O-Rings Figure 6.10 Example of Degraded O-ring Elastomers, which are most commonly used to Attacked by EO make O-rings, often will degrade in EO service. Experience within the EO industry has shown only a few elastomers to perform well in EO service. Note that elastomers that have performed well in EO service may not perform well in applications that involve with mixtures of EO and other chemicals. For example, industry experience has shown that even though some elastomers perform well in applications in pure EO service, they will degrade in high temperature EO/water mixtures. (Figures 6.9, 6.10, 6.11) The following is a list of elastomeric O-ring materials that laboratory tests have shown to be compatible with EO (refer to Appendix B for test methods and results): Chemraz® 505 Kalrez® 2035 Kalrez® 6375 Parker EPDM-740-75 Parker EPDM-962-90 Parker E-515-8-EPM The following elastomers are commonly used O-ring materials in many non-EO applications in the chemical industry. Laboratory test results show that these materials are not compatible with EO. Kalrez® 1050 LF Viton® 2F (V1163-75 FKM75A) Nitrile (N304-75 LT Nitrile 75) Figure 6.11 Example of Severely Degraded Butyl Rubber (Bu-70) O-ring in High Temperature EO-water Service

Figure 6.9 Butyl Rubber O-Ring Before and After Exposure to EO for 30 days

Packing (Valves) EO decomposition. Both flexible graphite and PTFE have been Aluminum insulation jacketing (sometimes called successfully used as packing materials in EO sheathing) and banding have a relatively low service. Corrugated, flexible, compressed, high melting point. In a fire scenario, insulation can be purity (98%) graphite ribbon and virgin PTFE lost when aluminum sheathing and bands melt or rings or chevrons, are examples of typically used burn. Stainless steel or galvanized carbon steel packing materials. jacketing and banding has superior fire resistance to aluminum. Durability of non-metallic materials in EO service varies with the material used and with the process For insulated flanges, it is helpful to install leak conditions. An inspection program can help detection tubes at the flanges. Sealed stainless determine the durability and required change-out steel bands installed around the flange can help frequency for the materials selected for a given prevent transport of liquid along the piping. application. (Figure 6.12) In horizontal lines, pre-formed snap- on insulation boxes can be adapted so that in the Insulation event of leakage the liquid will be drained. Insulation provides a degree of protection for metal walls of vessels, piping and other equipment from being heated to EO decomposition temperature by external flames. Selection of insulating materials for EO service takes into consideration many factors. Figure 6.12 Example of Flange Seal Band with Leak Detection Drip Tube Use of closed cell non-combustible insulation materials, such as cellular glass, reduces the potential for water absorption and for exothermic reactions in the event of an EO leak under insulation. Porous insulating materials such as magnesium silicate, calcium silicate, fiberglass, mineral wool, or asbestos can absorb moisture from the environment and retain EO, which may have leaked from gaskets, pinhole leaks, or elsewhere. If water is also contained in the insulation, the EO will react with the water to form polyglycols in a highly exothermic process, creating heat in and under the insulation. The heat of reaction is trapped by the insulation, resulting in high surface temperatures. In addition to the heat generated by the exothermic polyglycol formation, the polyglycols act as a fuel reserve. With air ingress into the insulation, polyglycols can spontaneously combust at temperatures of less than 212°F (100°C), depending on the liquid loading, insulation type, thickness, and rate of air ingress. EO leaks under porous insulation resulting in hot spots and internal ignition have been implicated in major industrial incidents. Two such incidents are discussed in Chapter 5. Note that although polyurethane foam is a nonporous insulation material, it is combustible and will not provide insulation protection in a fire scenario. Loss of insulation in a fire scenario can result in an

6.4 Unloading Facilities – while unloading the shipping vessel. If a manual Bulk Receipt of EO grounding system is used, consider including a ground indication light and/or interlocks. Design consideration for EO unloading facilities seeks, among other things, to minimize the Installation of a water deluge system and fire potential for contamination of EO. One mechanism monitors at the unloading site can help support to achieve this is to design a system dedicated on-site fire fighting, enhance the ability to “knock exclusively to EO. down” EO vapors, and provide water for the dilution of EO that might pool in the unloading area in the Backflow of process contaminants into an event of a release. Water deluge systems that can unloading EO railcar can contaminate the EO, be activated manually (either at the unloading so facility design will seek to avoid the potential site or at a remote location); by combustible gas for backflow. Intermediate storage vessels detectors; or by high temperature sensors are downstream from the offloading facility are available for use in EO service. commonly used to avoid backflow, but other engineering controls have been successfully used. Facility design considerations also include mechanisms to access the railcar dome while Locate the EO unloading area with sufficient unloading. DOT regulations require protection separation from inventories of flammable materials against inadvertent movement of the railcar during and with sufficient space to allow movement of connection of the loading/unloading hoses. Use railcars. Provide sufficient space in the unloading of an elevated rack for railcar dome access is an area for vehicle access. appropriate approach. Acceptable means of transfer from a railcar or intermodal (IM) portable tank into the storage facility include pressurization with nitrogen gas Figure 6.13 EO Unloading Facilities and pumping. If pressurization is used, design considerations include controlling the pressure applied to the railcar and adopting an appropriate means for venting off excess pressure. If EO railcars are pressure off-loaded with excessive nitrogen pressure, the relief valve O-rings may be damaged by premature weeping of the relief valve (75 psig safety valve setting per DOT requirements). Off-loading at pressures no greater than 50-55 psig greatly reduces this potential. Because of the flammability and reactivity hazards of EO, pressurized transfer by heating is not an acceptable practice. Typical layouts for a pressure transfer facility and a pump transfer facility are shown in Figures 6.13, 6.14, and 6.15. Design of unloading facilities also takes into consideration adequate electrical grounding, which prevents dangerous differences in electrical potential developing between the carrying vessel, body of the vehicle, piping, and ground or earth

Figure 6.146.14 Representative layoutlayout ofof EthyleneEthylene OxideOxide unloadingunloading facilitiesfacilities -– Pressurized transfer

Relief Valves PR 1 To Scrubber

PI RV PR 2 PR 3 PI Nitrogen Nitrogen (G ) (H)

(A) (B) LI Ethylene Oxide Storage Tank

Internal Cooler Tank WP FI Car To Process RO Lock or carseal open Process And Circulation Pump With Low Flow, Deadhead And Overheating Protection

SAMPLE PROCEDURE FOR UNLOADING WITH INERT GAS NOMENCLATURE (1) Check pressure, temperature, inventory of storage RO — Restrictive orifice vessel, and all piping line-ups before unloading TI — Temperature indicating device the EO railcar or IM portable tank. While unloading, PI — Pressure indicating device system pressure always remains in the inert region as determined by railcar and storage vessel PR 1 — Pressure regulator –35 psig setting min. temperatures (Figure 6.16 can be used as a guide for PR 2 — Pressure regulator –35 psig setting min. sites to establish minimum pressure(s) for unloading PR 3 — Pressure regulator –60 psig setting max. operations and onsite storage). RV — Safety valve set to open at 70 psig or (2) Verify valve H is open below (3) Open liquid valves A, G (Note: nominal set pressure for EO railcar (4) Open vapor valve B and apply nitrogen pressure relief valves is 75 psig as specified by the US DOT, with an acceptable range of 72- NOTE: Figure 6.14 and the sample procedure are provided 78 psig before opening) for illustration purposes only. Specific system design LI — Level indicating device should be made following consultation with appropriately WP — Wash point valve qualified engineers or experts. FI — Flow indicator

Figure 6.156.15 RepresentativeRepresentative layoutlayout ofof EthyleneEthylene OxideOxide unloadingunloading facilitiesfacilities –- Pump transfer

Relief (C) Valves PR 1 To Scrubber

PR 2 PI Nitrogen (F) (G) (H)

(A) (B) LI Ethylene Oxide Storage Tank FI

(D) (E) Internal Cooler Tank WP FI Car To Process

RO Lock or carseal open Process And Transfer Pump Circulation Pump With Low Flow, Deadhead With Low Flow, Deadhead And Overheating Protection And Overheating Protection

SAMPLE PROCEDURE FOR UNLOADING WITH NOMENCLATURE TRANSFER PUMP – RO — Restrictive orifice (1) Check pressure, temperature, inventory of storage LI — Level indicating device vessel, and all pipe line-ups before unloading the TI — Temperature indicating device EO railcar. While unloading, system pressure always remains in the inert region as determined by railcar WP — Wash point valve and storage vessel temperatures (Figure 6.16 can PI — Pressure indicating device be used as a guide for sites to establish minimum FI — Flow indicator pressure(s) for unloading operations and onsite PR 1 — Pressure regulator –35 psig setting min. storage). PR 2 — Pressure regulator –35 psig setting min. (2) Open liquid valves A, D, E, G PR 3 — Pressure regulator –60 psig setting (3) Close liquid valve C max. (4) Open vapor valves B, F RV — Safety valve set to open at 70 psig or (5) Check that the transfer pump is properly primed and below not vapor bound (Note: nominal set pressure for EO railcar relief valves is 75 psig as NOTE: Figure 6.15 and the sample procedure are provided specified by the U.S. DOT, with an for illustration purposes only. Specific system design acceptable range of 72-78 psig before should be made following consultation with appropriately opening) qualified engineers or experts.

6.5 EO Storage NOTE: EO in railcars is not as readily monitored for temperature or pressure EO Storage Vessels – Types increases as in specially designed storage A variety of EO bulk storage vessels have been vessels. Railcars have no capability successfully used by industry. Considerations for for external heat removal in case of EO vessel type selection include site location, size of polymerization or reaction with a contaminant. space available, and regulatory requirements, as EO railcar relief valves are generally sized for well as the features of the types of vessels noted fire conditions and not for reaction scenarios. as follows: Diking and containment are other important • Aboveground and free standing vessels considerations when designing an EO storage (three types): area. Locating above-grade EO storage vessels within a diked area, or an area otherwise designed — . Advantages: minimum Cylindrical (vertical) to contain vessel leaks or spills, can help prevent flame impingement; ease of monitoring other product spills from entering the EO storage inventory; less potential for accumulation of area. Protection of an EO storage vessel from polymer. possible exposure to a pool fire should be a major — Cylindrical (horizontal). Advantages: less consideration when designing an EO storage exposure to flying debris in the event of an area. A pool fire under an EO storage vessel is incident. a very hazardous situation that can lead to an — Spheres. Advantages: less potential for EO decomposition. If diking is used, it is very accumulation of polymer. important to design the EO storage area with an adequate grade under the storage vessel • Mounded (vessels at grade level covered with and in the storage vessel dike area so that any sand or soil) and buried vessels. liquid release will drain away from the vessel and — Advantages: passive fire protection and cannot form a pool beneath or adjacent to the protection against impact. vessel. Another containment option is the use of a drainage system under EO storage vessels that — Disadvantages: unable to readily detect leaks if not double walled; top take off routes liquid to a secondary containment area eliminates the need for underground flange located well away from the EO storage vessel. This connections but increases potential for approach can be used to contain both EO spills polymer accumulation in the sump; it can be and firewater or dilution water. difficult to inspect external shell condition, Fire Protection Systems sometimes necessitating internal entry to verify shell integrity. Fire protection measures are also considered in the design process. Passive fire protection, Selection of storage vessel type will be dependent such as insulation, can provide additional fire on company philosophy, plot space, and regulatory protection for those vessels located above grade requirements. Long-term and extended storage of and not mounded or buried. Remotely operated, EO should be made in storage vessels designed or fire-resistant valves allow isolation of the storage appropriately managed for this purpose. vessel in the event of an emergency. Additionally, Design Considerations – excess flow check valves can be used at the vessel inlet and outlet lines to minimize releases in the EO Storage Vessels event of downstream piping and equipment failure. Vessel capacity is a relevant design consideration NFPA 58 and API 2510 and 2510A may apply to the for storage vessels. Providing sufficient vessel design of fire protection systems for EO storage capacity to allow unloading of an entire railcar and processing areas. These codes describe in one continuous operation will minimize railcar fire protection systems with passive (insulation) connection/disconnection operations and the and active (deluge/sprinkler) systems. Areas potential for EO release and personnel exposure. appropriate for deluge protection can be identified

using process hazards analysis methods that Storage vessel contamination, examine the severity of the consequences of a fire backflow and inerting scenario. Contamination of EO in storage vessels can lead A fire protection system takes into consideration to an uncontrolled runaway reaction with serious whether fire water supplies are located so as to be consequences if facility design does not include readily available and sufficient in volume so as to measures to prevent or mitigate such incidents. adequately dilute a spill. Drainage design for the Possible sources of storage vessel contamination system includes the capacity to retain emergency include: water whether used for cooling, fire fighting, or • Backflow from other process areas dilution purposes. • Incorrect vessel line-ups, allowing other Storage vessel design pressure and materials to enter the storage vessel inerting of storage vessels • Contaminants in the inerting gas A primary consideration in vessel design is • Contaminants such as water, cleaning solutions vessel pressure. Consult the current ASME Code and other materials inadvertently remaining for Unified Pressure Tanks for the minimum after maintenance design working pressure consistent with process requirements, including consideration of the Backflow of process fluids into EO storage vessels blanket inert gas pressure needed to maintain a from other process areas, such as reactors, can non-decomposable vapor space. result in an extremely rapid, exothermic reaction. Be aware that storage vessel emergency relief Understanding pressure is extremely important due valve /device sizing and cooling system capacity to the potential for pure EO vapor to decompose (if so equipped) may not consider runaway explosively. Refer to Section 2.3 for more reactions as a design case. Consequently, system information. EO vapor spaces can be rendered engineering is critical to prevent or minimize non-decomposable by dilution with the appropriate backflow from occurring. concentration of an inert gas. In practice, vessels are most often inerted with nitrogen and are Engineered backflow prevention systems can maintained in the non-decomposable region by provide a reliable and robust system to prevent controlling pressure and temperature. backflow of process fluids into EO pipeline and storage facilities. See discussion on Prevention CAUTION: Carbon dioxide is generally not used of Backflow in Reactors in Section 6.6, Reaction as an inerting gas. CO2 exhibits very high Systems, for more information. solubility in liquid EO (approximately ten times that of nitrogen). Historically, check valves have been used as part of an overall system to prevent backflow of Based on existing published data, Figure 6.16 process fluids into EO supply pipeline and storage illustrates the storage pressure needed in fixed systems. Industrial experience has shown that a storage vessels to achieve a non-decomposable single check valve alone may not be an adequate EO vapor space, as a function of liquid storage backflow prevention device. Multiple check valves temperature. (Refer to Chapter 9 and Appendix C of the same type may experience common mode for pressurization of railcars.) The figure assumes failures. Consider multiple check valves of different use of nitrogen as the inerting gas. The graph is a types and/or automatic isolation valves to protect useful tool for calculating an appropriate storage against backflow. temperature for EO facilities and operations. In selecting an inerting pressure, a key consideration EO users should be aware that inerting systems is to maintain the vapor space in the non- are themselves potential sources of contamination. decomposable or inert range over the full range of Systems used to prevent inert gas contamination EO storage temperatures. Calculating the inerting include: pressure required in the event of loss of cooling • Dedicated sources of inert gas, such as high- can be factored into the storage vessel design pressure cylinders, or liquid nitrogen storage process. and vaporizers.

Figure 6.166.16 Total pressure required to inert vapor above ETHYLENEEthylene Oxide OXIDE with wit h nitrogen diluent

200

150 NON-DECOMPOSABLE

100

TOTAL PRESSURE, Psi a 50 DECOMPOSABLE

0 20 40 60 80 100 120 140 160 180 Liquid Temperature, °F Based on “Prediction of decomposition limits for ethylene oxide-nitrogen mixtures”, J.L. Brockwell; Plant Operations Progress, vol. 9, 98-102, April 1990

• Area knockout pots with high liquid level Storage vessel pressure relief systems alarms or interlocks on nitrogen supply lines. Pressure relief devices are sized to relieve pressure This design can prevent contamination of EO developed by the controlling contingency identified with other chemicals while also preventing the for that process. A safety analysis of the process contamination of other plant systems with EO. is conducted to define the characteristics of the • Continuous analyzers (for contaminants) on controlling contingencies. Pressure relief devices, inerting systems. however, are not designed to provide relief in cases • On a high pressure nitrogen supply pipeline – such as explosive decomposition of EO. Additional (1) the EO user uses nitrogen first, ahead and information about proper sizing of relief systems upstream of all other users and/or (2) there can be found at: are backflow prevention systems at each point • API Recommended Practices #520-521 of nitrogen withdrawal, for each user (a single (addresses sizing of pressure relief valves; check valve is not relied on as the sole means these practices do not cover reaction of preventing inert gas contamination). scenarios) Incorrect vessel and pipeline manifolding can also • NFPA 58: Liquefied Petroleum Gas Code lead to contamination of the EO storage vessel, (pressure relief guidelines) resulting in the potential for violent reaction. • ASME Code for Unfired Pressure Vessels Dedicated EO storage and piping systems are used (design standards for relief protection). from off-loading to storage to reduce the potential for contamination. Clearly marked and identified Uncontrolled releases can be minimized by setting EO pipelines, especially in the receiving area, have an adequate margin between ordinary operating been used to prevent unloading an incompatible pressure and the design pressure of the storage fluid into an EO vessel. vessel to minimize such uncontrolled releases.

With regard to the routing of relief valve method of emergency relief; such devices discharges, some systems are designed to vent would allow the continued escape of EO from to the atmosphere, while other systems are the storage vessel.) If equipped with a bursting/ designed to feed into a flare or scrubber. If routing rupture disk upstream of the pressure relief to a scrubber, consider the pressure drop across valve, a method of indicating failure of the disk, the scrubber and the possibility of plugging or such as a pressure gauge between the disk and damage in the scrubber in the design. If vented pressure relief valve, might be considered. to atmosphere, discharges from pressure relief • Introducing a small nitrogen stream into the devices are designed with adequate height nozzle upstream of either the bursting disk and discharge velocity to prevent contact of or relief valve to sweep away EO and prevent flammable vapor clouds with potential ignition polymer formation in the nozzles. If the sources. Addition of steam to the relief valve outlet discharge is in to a header system, a nitrogen piping, manually or automatically, can improve sweep downstream of the relief valve may be dispersion and reduce flammability of the EO warranted. plume. Relief valve discharge piping routed to • the atmosphere is also designed to minimize Using stainless steel as a material of potential for human exposure. See Section 6.8 for construction for piping, isolation valves, and additional information on design considerations for relief valves. controlling vent emissions. Note that the lifting of a storage vessel relief Atmospheric discharge from safety valves and valve or similar action by other pressure relief vents can result in a fire or an explosion. In some devices is not considered to be a routine pressure incidents, flames from ignited vent streams were management event for EO service. These devices found to have impinged on vessel walls or piping. are intended to function as emergency venting Directing vents and safety valve discharges of EO devices and not as a part of routine pressure and other flammables well away from equipment control practices. or piping containing EO is therefore an important Instrumentation design step. EO storage instrumentation is designed to provide Rupture disks on EO storage vessels should not accurate level measurement, accurate temperature be used for pressure relief because they will measurement and sufficient data to determine not reseat. Use of a rupture disk in conjunction that the storage vessel is inerted at an adequate with a pressure relief valve for control of fugitive pressure to stay out of the decomposable region. emissions may, however, be appropriate. Consider the following when designing instrument In EO pressure relief system nozzles, blockage systems for EO storage: by polymerization has been observed in both EO • Remote monitoring and trending of EO storage liquid and vapor service (in EO vapor service, the instrumentation. EO condenses and polymerizes). This condition can be minimized or avoided by a number of different • Installation of multiple, independent level approaches, including, but not limited to: measurements (a level measurement with an independent high level alarm). • Locating pressure relief devices as close to the vessel shell as possible. Stagnant vapor in • Installation of multiple, independent long lengths of dead-ended pipe may promote temperature measurements and alarming on polymer formation. high temperatures. • Bursting/rupture disks can be placed on the — Multiple temperature measurements might upstream side of the pressure relief valves to include, especially for larger storage vessels, help prevent accumulation of polymer in the temperature monitors at different liquid pressure relief valve. (Non-reclosing bursting/ levels to differentiate between potentially rupture disks are generally not used as a stratified EO layers that could represent isolated areas of reaction.

— Monitoring and alarming on rate of rise • Lower temperatures will result in a smaller of storage temperature. Changes in the fraction of EO being vaporized in the event of rate could indicate intensification of a a leak. The hazard of a pool of EO liquid may contamination reaction and help signal the be mitigated more successfully than that of a need for corrective actions or emergency vapor cloud. response. One possible drawback of refrigeration, especially • Monitoring of pressure, with alarms for both at low temperatures, is a reduction of the solubility high and low pressure (low pressures indicate of EO polymer, which may cause the precipitation loss of inerting gas). of polymer that has already formed. This can cause The use of stainless steel tubing for instrument plugging of instrument tubing and plugging of impulse lines in EO service will reduce the transfer lines. likelihood of polymer formation and plugging. Also Another issue that must be considered with note that the use of remote diaphragm, sealed refrigerated EO storage is detection of a reaction differential pressure transmitters, “bubbler” dip in the storage vessel. If a reaction occurs in an tubes, ultrasonic level devices, vessel radar or EO storage vessel and the refrigeration system is nuclear level indicators can reduce the potential controlling the EO temperature, the refrigeration for erroneous level indication caused by polymer system will remove the heat of reaction until the formation. Gauge glasses are typically not used refrigeration system capacity is exceeded. In because they have the potential to be damaged this scenario, the operator may not be aware a and/or leak. As mentioned above, plugging from reaction is occurring until the reaction has been polymer formation can result in false gauge level going on for quite a while. If refrigeration is used indications. for EO storage, consider installing instrumentation Although the use of mercury in instrument systems to calculate the heat load on the refrigeration has declined considerably in the past few decades, system and include an alarm on high heat load and instances do occur where elemental mercury may increasing heat load. be present within an instrument system or device. Reference [5] is a useful study of the relative See the Metallic Materials discussion in Section 6.3 risks of storing EO at moderate temperature and for more information about the use of mercury in pressure versus low temperature and pressure. EO service. EO storage refrigeration designs can incorporate refrigerated coils within the storage vessel, an Refrigeration external vessel cooling jacket, or an external heat EO can be stored in refrigerated or non- exchanger and circulation pump. Internal coils refrigerated storage vessels. Refrigerated storage can offer better heat removal in the event of an has the following benefits: exothermic reaction within the storage vessel. • Lower temperatures decrease the rate of EO Internal coils, however, can potentially contaminate polymerization, reducing the potential for the storage vessel if a leak occurs. Depending on polymerization-related difficulties such as the coil configuration, heat transfer area for internal vessel nozzle plugging. and external coils may be less at lower levels in the vessel as the coils are not in contact with the • If the EO is contaminated, refrigeration systems liquid. Heat transfer fluids such as water or glycols can remove all or part of the heat of reaction. In could react with the EO in the vessel. External some cases, this substantially assists in control heat exchangers may also contaminate the vessel of the reaction; in others, it slows the reaction, contents due to leakage, but the leak can be providing more time to implement control or readily isolated for a more timely and expeditious disposal measures. repair. External vessel cooling jackets minimize • Lower EO storage temperature allows a lower the potential for contamination but may be less inert gas pressure to maintain the vapor space effective at heat removal. in the non-decomposable region.

Maintaining the refrigeration system coolant resultant mixture. In fresh water, EO hydrolyzes pressure below that of the storage vessel reduces to ethylene glycol very slowly, with a measured the potential for contamination of the vessel half-life of 14 days. Acids or bases can be contents in the event of an exchanger leak. In directed to the pond to catalyze the water – EO such a case, a leak can be identified by routinely reaction and speed the conversion of EO into monitoring the coolant for EO. glycol. During conversion EO vapor will continue In practice, storage temperatures range from 20°F to be evolved. to 80°F (-6°C to 26°C), with a typical range of 40°F EO users must carefully consider the effects of any to 60°F (4°C to 15°C). Operating with temperatures of these actions on the health and safety of their in the lower end of the range can result in workers and communities and on the environment. precipitation of EO polymer. The consequence of These actions should only be taken as part of a this can be reduced by operating at EO storage well-defined, site-specific emergency response temperatures comparable to those of the EO plan that has addressed environmental and worker supplier. safety regulatory requirements. See also the Consider incorporating alarms in the refrigeration discussion in Chapter 10 regarding emergency system design to alert individuals in the event response and the discussion of personal protective the system shuts down or begins to lose cooling equipment selection in Chapter 7. capacity. 6.6 Reaction Systems Emergency Disposal of Vessel Contents Consider the following elements in the design of Design of an EO storage system includes EO reaction systems: provisions for the disposal of EO inventory in the • event of a contamination reaction. The objective Prevention/minimization of backflow from is to safely dispose of storage system contents reactors into EO storage vessels. before the rate of temperature increase becomes • Prevention/minimization of build up of too rapid and/or the concentration of EO in the unreacted EO. vapor phase approaches or enters the non-inert • Prevention/minimization of explosive mixtures in region. Options in current practice include: reactor vapor space. • Reacting the EO to glycols or other derivatives • Heat duty requirements. by feeding to downstream users (under • emergency disposal conditions, a rapid rate of Catastrophic failure modes. consumption is the goal of the reaction) • Materials of construction. • Depressuring the storage vessel. Examples More details about these elements are discussed include discharge into a scrubber, flare system, below. or to an elevated discharge point. Depressuring can be a highly effective response because Prevention of Backflow from Reactors evaporation of the EO during this procedure Catalysts in widespread use in EO reaction provides an auto-refrigeration effect, which systems, such as KOH, have the capability to cools the vessel contents. See section 6.8 for initiate EO polymerization and accelerate other the EO-specific design considerations for a flare reactions if they backflow into EO storage vessels. system. These reactions are exothermic and can result in • Transferring to a holding system and diluting uncontrolled heat release and vessel rupture. Note with water. If the transfer is to a body of water that storage vessel emergency relief sizing does such as a pond, the volume of the pond must not normally consider runaway reaction as a design be sufficiently high to allow a dilution ratio of case. Likewise, storage vessel cooling systems at least 22:1 volume/volume water to EO to are ordinarily designed to remove heat gain limit the flammability of the vapor above the from ambient sources or to remove temperature after unloading a railcar. Storage vessel cooling systems are generally not designed to address

the extremely rapid reaction rate of EO and its controlled. Establishing automatic EO feed shut highly exothermic nature, so it is important that down points based on maximum allowable feed engineered systems be employed that prevent rates at a minimum reaction temperature or on backflow from occurring. Examples of engineered analyzed unreacted EO concentration present in systems for backflow prevention include: a reactor are common protection methods. On- • Triple block and double bleed automatic valves line analyzers are another means of continually activated by three independent inputs; monitoring unreacted EO levels. • Double block and single bleed automatic valves Some conditions that can lead to an accumulation activated by two independent inputs; of unreacted EO include: • • Double block and single bleed automatic valves EO addition rate higher than design limits activated by one independent input; and • Poor mixing of reactants and catalysts • Multiple high performance check valves (single • Low concentration or lack of catalyst check valves are generally not considered a • Low reaction temperature reliable means, by themselves, to prevent EO backflow). If the control parameters are outside the design limits, automatic shutdown of EO feed is typical. • Combinations of automatic block valves and check valves Possible indications of unreacted EO include: • Historically, check valves have been used as High reactor pressure part of an overall system to prevent backflow of • High EO concentration in EO vapor space process fluids into EO supply pipeline and storage • Lack of heat of reaction systems. Industrial experience has shown that a single check valve alone may not be an adequate An additional hazard occurs if reactor product backflow prevention device. Multiple check valves contains significant quantities of unreacted of the same type may experience common mode EO. This can result in release of EO vapor from failures. Consider multiple check valves of different product storage vessels. Not providing sufficient types and/or automatic isolation valves to protect reaction time can contribute to such a condition. against backflow. See Section 5.3 for a discussion on a release of unreacted EO. The operation of an engineered backflow prevention system should be checked on a regular Prevention of Explosive Decomposition of basis. For instrumented systems, consider the EO in Reactor Vapor Space need for redundancy of the sensing element, logic The amount of diluent required to provide a non- solver and final control element to provide a robust decomposable mixture in the reactor vapor space protection system. Diversity in sensing elements is varies with temperature and EO concentration. often used in engineering design, such as pairing The reactor pressure control system should be a low flow sensor with a differential pressure meter designed to provide adequate diluent pressure to across the EO feed valves. Setting the EO feed prevent decomposable mixtures over the expected pump discharge pressure higher than the reactor range of reactor operation. Parameters to be safety valve set pressure is a common practice to considered when determining decomposability minimize the potential for backflow. limits include: Prevention of Buildup of Unreacted EO • Temperature operating range Accumulation of unreacted EO in a reaction system • Pressure operating range can result in a runaway reaction exceeding the • Reactor mechanical design (for example, batch, designed heat removal and relief capacity of semi-batch, CSTR, plug flow, or circulating loop the system. The rate of reaction is almost always reactor) dependent upon the concentration of EO present; thus, by controlling the EO feed rate and the • Solubility of nitrogen or other diluent employed reaction temperature, the reaction rate is also in the reaction mixture

Some reaction system designs allow EO versus total system pressure as is presented in decomposable EO concentrations in the vapor Figure 6.18. space. These designs have typically eliminated Unless a process specifically requires oxygen for sources of ignition such as mechanical agitators. In the process chemistry, all air or oxygen should be such designs, it is important to eliminate external excluded from the reactor space. The presence sources of heat such as hotspots in the insulation. of oxygen reduces the lower decomposable Figure 6.17 illustrates the molar nitrogen concentration of EO and reduces the minimum concentration at the EO decomposable limit versus ignition energy for EO. See Section 2.3 for further temperature for several total system pressures as discussions on the combustion properties of EO. measured by June and Dye. [6]. All data is for the nitrogen-EO binary system. The presence of other Reactor Design and Instrumentation materials may invalidate these predictions. This Consider designing reactor cooling systems with graph differs from Figure 6.16 in that it addresses excess capacity to remove the heat generated by EO concentrations at saturation and below. Figure the onset of a runaway reaction. Since designing to 6.16 is applicable only to systems containing both remove 100% of the heat generated in a runaway liquid and vapor EO in equilibrium. For systems reaction scenario may not be practical, automatic such as vessels and reactors where no liquid EO feed shutdowns are often utilized to restrict the EO is present, Figure 6.17 may be used as a tool magnitude of incidents. to assist in the determination of the nitrogen Consider designing reactor control systems to stop pressure required to have a non-decomposable EO addition in the event of the following: composition. An alternate way of representing the data that may be more useful if the vapor oxide • Excess rate of EO feed concentration is being measured is to plot mole% • Failure to add other reactants

Figure 6.176.17 EOEO DecomposableDecomposable LimitsLimits versusversus MolarMolar NitrogenNitrogen ConcentrationConcentration Ethylene Oxide Decomposition Limits (Required Diluent Concentration as a Function of Total System Pressure)

NON-DECOMPOSABLE REGION

80 PSIG

45 PSIG 40

25 PSIG DECOMPOSABLE REGION

30 Nitrogen Concentration, Mole % 10 PSIG

20 100 150 200 250 300 350 400 Temperature, °F

• Failure to add catalyst is a consideration in the design of safety systems. • Loss of mixing or agitation Redundancy and on-line error detection are common features when analyzers are used as part • High reactor temperature of reaction shut down systems. • Low reactor temperature • Loss of cooling 6.7 Piping and Pumps • High reactor pressure Piping Systems • Low reactor pressure Carbon and stainless steel are suitable materials • Loss of utilities such as electricity for EO service piping. Piping constructed of • High EO concentration in vapor or liquid non-metallic materials has limited fire resistance, can be subject to chemical attack, and is not If practicable, reactor vent and/or safety valve considered suitable for EO service. Stainless steel capacity can be sized to help mitigate upset piping systems retard the development of rust, so conditions. these systems may eliminate the need to remove Process analyzers can be used to monitor EO rust from the interior of the piping prior to initial concentration in the reactor vapor space to service and after outages where the interior of maintain operation below the decomposable limit. the pipe is exposed to the atmosphere. Carbon When process analyzers are used as part of a steel systems, on the other hand, may require safety system, continuing maintenance is important significantly more service over their lifetimes to to maintaining high reliability. Analyzer cycle time remove rust.

Figure 6.18 Decomposition Limit of Mole % EO versus Total System PressurePressure EO Decomposition Limits

(Mole % EO versus Total Pressure for EO-N2 Binary System

65 DECOMPOSABLE

55 Mole % E O 140 F

194 F 50 248 F

45 302 F

NON-DECOMPOSABLE 356 F 40 10 20 30 40 50 60 70 80 Total System Pressure (PSIG)

Proper installation and maintenance of insulated • Minimizing valves in EO piping that can be used piping is especially important because moisture to connect/introduce foreign products into the can infiltrate under the insulation, damaging the piping system; pipe’s protective coating and reducing metal • Providing clearly visible, permanent labels on thickness and strength. Carbon steel systems EO piping; and are more susceptible to water-initiated external • corrosion than stainless steel systems, but Minimizing permanent connections to water, regardless of the type of steel used, it is important steam, or other substances that are reactive to periodically remove insulation and verify the with EO. integrity of piping systems. Use of Hoses in EO Service EO polymerization is a design consideration for EO Hoses are generally not used for process line piping systems due to the relatively high amount of applications in EO service because they cannot surface area of the piping system. Polymerization, be effectively insulated for fire protection. In an once begun, can continue over extended periods external fire situation, a hose containing EO is very of time in a piping system. Construction of piping vulnerable to EO decomposition. systems to minimize the number of low points and dead spots (“stagnant areas”) helps avoid or slow There are four applications where hoses are polymerization. Designing piping lines to be as commonly used in EO service. The first three are short as possible with gravity drainage to points 1) EO sample systems; 2) EO loading or off-loading at which contents can be purged from the system connection to railcars; and 3) hoses for blowing with nitrogen is another useful technique. In areas EO equipment clear of EO with nitrogen. For where emptying stagnant EO lines is not feasible these three applications, the hoses are used for — for example, a long EO charging line to a batch a limited time period and then blown clear of EO reactor — a pipe loop that circulates back to the with nitrogen. The fourth application where hoses storage vessel may be considered as a design are commonly used in EO service is in filling and option. Chilled tracing of lines that may sit idle can unloading small EO containers such as EO drums also reduce the polymerization potential. or cylinders. In this type of application, hoses are often in continuous use, but they are also well Welded and/or flanged construction is protected with deluge systems and blown clear of generally used in EO piping systems because EO with nitrogen after use. When hoses are used it is considered to have less leak potential than in EO service, larger hoses are typically corrugated threaded joints. For instrumentation connections, stainless steel with a stainless steel braid outer consider using welded or flanged construction jacket with welded fittings. For small sampling up to the instrument/instrument tubing isolation hoses, PTFE hoses with stainless steel outer braid valve. The design process should seek to minimize are sometimes used. Note that the crimped or the number of flanges because each flange banded-type end fittings often used in conjunction represents a potential leak source (including with PTFE hoses may be more susceptible to fugitive emissions). Where flanges are necessary, end connector separation than welded-type end they should utilize gasket materials suitable for EO connections. service. It is extremely important to note that loading arms Preventing or minimizing introduction of or hoses used for loading and off-loading EO contaminants into the system is a critical design railcars cannot be insulated for fire protection. For element for an EO piping system. Some key this reason, consider the use of deluge systems considerations are: and/or fire monitors to protect the hoses and arms. • Operating EO piping as dedicated piping for EO product only;

Thermal expansion protection system. A high purity nitrogen supply is generally in liquid piping systems appropriate for this type application. System and atmospheric conditions are monitored by qualified EO has a high coefficient of thermal expansion. personnel in order to determine the proper volume Heating (ambient heating or otherwise) of a closed of inert gas required. or isolated system containing EO can result in high pressures in a short time period, leading to Valves gasket failures, or in more severe cases, line or The potential for trapped EO in valve cavities is an equipment rupture. For this reason, liquid EO is important consideration in valve design, as well not confined in lines closed at both ends unless as in facility design. EO trapped in valve cavities this is otherwise unavoidable. Where the confining can polymerize and render the valve inoperative, of liquid EO is unavoidable, lines are equipped or create an undesirable pressure buildup due to with adequate relief valves to address potential thermal expansion. To address this issue, valve high pressures. EO discharged from the relief designs can be selected that minimize trapping valves is then captured and either returned to an of EO. Gate valves, globe valves, and high- appropriate location in the process or disposed of performance butterfly valves have all performed in accordance with applicable plant requirements well in EO service. Ball valves and plug valve and regulatory provisions. designs have also been successfully used in EO Diaphragm-type surge suppressors providing a service, although some have the potential to trap vapor space that can be displaced by expanding EO liquid when the valve is in the closed position. liquid have been utilized for EO systems on a Controlling fugitive emissions is also an important limited basis with varying levels of success. A key consideration in valve design and selection. issue with this type of device is proper material selection for the diaphragm. Suppressor protection Decomposition Flame Arrestors devices of this type are routinely inspected and maintained so that the device will perform Control and avoidance of ignition sources and as needed. Consult the manufacturer for more the use of an inert gas diluent are available information to select a design appropriate to mechanisms used to help avoid decomposition facility needs. events. Where process conditions prevent the use of these mechanisms, consider the Surge suppressors without diaphragms that use of decomposition flame arrestors. Flame provide an inert compressible vapor space in arrestors function by preventing the passage direct contact with EO (commonly known as of a decomposition “flame” in one part of the nitrogen snubbers) have also been used in EO process from propagating to an area with a large service to accommodate thermal expansion. inventory of material. The use of flame arrestors Because nitrogen is soluble in EO, it is important to may be considered in EO lines entering or leaving periodically verify the inert gas volume needed to an EO storage or processing area where large maintain the effectiveness of the nitrogen snubber. inventories may be present. “In-process” flame Some nitrogen snubbers have a small, continuous arrestors can also complement the use of vapor nitrogen make-up flow. (EO) compressors or air-cooled heat exchangers. Two alternate means of addressing thermal “Off the shelf,” conventional flame arrestors are expansion are to install chilled water tracing, or not likely to be designed for the high propagation install a continuous circulation loop on piping that speed of EO decomposition flame fronts. A general may be susceptible to thermal expansion. disadvantage of flame arrestors is their high In piping systems without the surge suppressors surface area and small passages, which makes described above or without pressure relief them susceptible to plugging if EO polymerization systems, consideration can be given to displacing occurs. a portion of the liquid EO in a piping system with an inert compressible gas prior to isolating the liquid

One example of a simple flame arrestor design • Local or remote monitoring of seal pot level with that has been used packs a bundle of half-inch low and high level alarms; diameter tubes into a pipe shell. Limited testing • Instruments/remote alarms capable of warning suggested that this design might be effective in EO of excessive seal pot pressure resulting from a service. Research has indicated that the diameter seal failure; and and length of the tubes are critical to an effective • design. However, there are to date no published Safety relief device(s) on pressure seal pots. data on the effectiveness of flame arrestors for EO A bypass flush of EO from the pump discharge to service to help guide design considerations. the inner seals removes frictional heat. Seal fluids successfully used on double and Pumps tandem mechanical seal systems include 50% Carbon steel, stainless steel or ductile iron are aqueous solutions of ethylene glycol, pure ethylene appropriate materials for pump bodies in EO glycol, and/or pure diethylene glycol. Note that service. The brittle nature of cast iron makes its a properly functioning double mechanical seal/ use inappropriate for EO systems. pressurized seal fluid system continuously adds small volumes of seal fluid into the EO product Pump Designs being pumped. This generally does not have Centrifugal-type pumps are commonly used in a product quality implications and is considered wide range of EO service conditions. Diaphragm- acceptable for pumping applications where type pumps are also used but their use is generally the pumped EO is continuously consumed or limited to situations where process conditions converted to other products; it may therefore be favor this type of pump (e.g., high pressure, low less acceptable for pumps loading transportation flow) over centrifugal designs. Other types of pump containers or feeding EO into storage vessels with designs are not widely used in EO service; before long product turnover time intervals. using another design type, consult with qualified Dry gas (nitrogen) seal systems use nitrogen as engineering personnel. the seal purge material. These seals allow a very Pumps with double or tandem mechanical small, continuous flow of nitrogen into the process. seals and sealless pumps are commonly used Dry gas seals have been successfully used in for purposes of reducing fugitive emissions EO service. When dry gas seals are used, it is in compliance with applicable regulatory important to monitor the nitrogen pressure and the requirements. In the event of seal or pump failure, flow and alarm on low pressure and high flow. A low these pumps may result in a lower volume of EO nitrogen pressure or a high nitrogen flow indicates being released (reducing potential personnel a seal failure. exposure and fire and explosion hazards) than single seal designs. Sealless pumps Sealless pump designs such as magnetic drive Pumps with Double or Tandem Seals pumps and canned motor pumps have also been Pumps with double or tandem mechanical seals successfully used in EO service. An advantage of are widely used in EO service. Double seal systems these types of pumps is the elimination of fugitive using a pressurized seal fluid introduce small emissions because of the elimination of an external volumes of seal fluid into the process across the seal system on the pump shaft between the inboard seal; an important criterion, therefore, impellor and driver. in the selection of a seal fluid is its relative non- Design considerations for these types of pumps reactivity while in contact with EO. Tandem seals include: with an unpressured seal fluid system greatly reduce the potential for introducing seal fluid into • EO without foreign particles or polymer is used the process, but require a suitable disposal system to lubricate pump bearings. Evaluate the need for collecting and disposing of EO vented from for a filtering system (magnetic or element type) the seal system. Consider including the following to remove particles and polymer from the EO in components in a seal fluid system:

the suction line feeding these types of pumps. unloading areas, and storage vessels. Equipping Magnetic filters are commonly used on pumps pump areas with fixed firewater spray systems and/ with magnetic couplings. or remote firewater monitors provides additional • Sealless pumps are more susceptible to spill ignition protection. If water spray systems damage caused by low suction pressure than are used, many are available that are capable some other pump designs. Consult the pump of remote activation, such as by heat-sensitive manufacturer’s net positive suction head devices, combustible gas detectors, and/or (NPSH) requirements with regard to the suction personnel. line. Combustible gas detectors (CGD) or EO-specific • Entrained gases in EO such as nitrogen can sensors/alarms can be installed in the immediate impede pump operation; two such examples vicinity of the pump. Consider using CGDs/EO- are reduced or lost suction or reduced pump specific sensors to activate pump area water spray bearing lubrication. Removal of entrained gases systems. from EO used to lubricate bearings will help Pumps can be located an adequate distance from maintain effective pump operation. If necessary, a road to address possible damage from a vehicle equipment can be installed to remove entrained collision. If a pump is located in close proximity to a gases from liquid before it enters the pump. road, consider additional facility designs to protect • Damage to the containment shell can result in a the pump, such as placing a physical barrier at the flammable toxic release. A double containment edge of the roadway or adding additional physical shell design can reduce the likelihood of a protection around or to the pump. release . Pump Instrumentation If a rotor on a magnetic drive pump locks up, EO overheating — which can lead to a violent the magnets decouple and the driver continues decomposition – is a primary safety focus in to run, then the pump contents will experience the design of EO pumping systems. There are a rapid temperature rise due to the magnetic many possible sources of additional heat to flux. Consequently, the response time available pumped EO, including: operation of EO pumps in to prevent pump failure and decomposition of a dead-headed or non-flow condition; improper pump contents may be significantly less than the pump operation; undetected pump mechanical response time likely to be available in a similar damage; or inadequate cooling of recycle streams. incident with a conventional centrifugal pump. For examples of specific protective measures Consider the use of high and low power meter to address EO overheating in pumps, refer to monitoring and shutdown to address this issue. Figure 6.19 Pump Hazard Mitigation Redundant sensors and multiple shutdown initiators are valuable tools in EO pump safety Physical Facilities systems for identifying and responding to Locating pumps within an impervious containment overheating scenarios, but before selecting a area provides protection against spills or leaks sensor/shutdown system, it is helpful to conduct leaving the plant site or spreading to other process a thorough process hazard analysis of the system areas inside the plant. This type of protection is with the support of appropriately qualified commonly provided by locating pumps inside engineers. The decision regarding the number curbed areas constructed of concrete or other of alarms and shutdown initiators to install in a materials suitable for containing EO liquid. specific system considers the potential severity of and opportunity for an EO incident with regard Because EO spills may ignite, creating the potential to the pumping system under consideration. for flame impingement on nearby equipment, EO pumping systems have been successfully locate pumps and any associated containment protected by alarms and shutdowns with systems areas an appropriate distance from process using two sensors where one sensor is triggered equipment, transportation container loading/ (1 out of 2 initiation). Additional sensors can be

added with alarms/shutdowns triggered by a measures to rapidly isolate the pump, such as use group of sensors (2 out of 3 initiation). In certain of remotely activated isolation valves on pump circumstances, it may also be appropriate to set suction piping and discharge piping. alarms/shutdowns to trigger when all sensors reach their initiation point (2 out of 2 or 3 out of 3 Filter Systems initiation), but this approach is generally not used Filter systems are designed to trap and remove without complete review and approval in advance solid particles from EO. EO can be filtered before it from qualified personnel. is delivered to the customer; before it is delivered Maintaining minimum flow through a recycle line to storage; before it is loaded into transportation can be used to prevent pump deadheading when containers; before delivery to a pump; or at other forward flow is shut off. Minimum flow can either points in the process. Both magnetic-type filters be constant (through a fixed orifice) or automated and removable element-type filters have been (through a control valve when forward flow is lost). successfully used by industry. Two mechanisms to control the heat of the EO in Magnetic-type filters are designed to attract and the recycle line are to equip the recycle line with a remove iron and iron oxide particles from the EO. cooler or to return the recycle line to a large heat These materials are not present in the EO product sink, such as a large storage vessel or process initially, but can enter the EO as it comes into vessel. contact with carbon steel, such as that in piping or Additional protective measures may be necessary equipment. for pumps operating above 3600 rpm. Consult with Removable filter elements are designed to remove the pump manufacturer regarding these types of iron and iron oxide as well as polymer that may operations. have formed and precipitated from the product as Where EO pumping systems are connected to large it moves through the process. inventories of material such as in storage vessels A large variety of removable filter elements and filter or rail cars, failed pumping systems are isolated as designs may be applicable for EO service operation. quickly as possible. Design considerations include Cotton and polypropylene are two materials that

Table 6.1 EO Pump Shutdown and Alarm Considerations

Pump Type Potential Hazard Typical Protection Systems

Centrifugal, magnetic EO decomposition resulting Minimum flow recycle (automated or always open) drive, or canned from high temperature Low flow shutdown

High discharge temperature shutdown

Delta temperature across pump shutdown

Pump motor low power shutdown

Pump motor high power shutdown

Low Level in pump suction vessel

Canned EO release/ Rotor thrust displacement shutdown EO decomposition

Centrifugal - double EO seal failure release Seal pot low pressure alarm seal Seal pot low level alarm

Centrifugal - tandem EO seal failure release Seal pot high level alarm seal Seal pot high pressure

have been successfully used in EO service. scrubber column filled with random packing Bear in mind the possibility of thermal expansion such as Pall rings. EO is absorbed by an aqueous occurring when filters are not operated with stream running countercurrent to the vent gas. continuous flow. Iron oxide particles inside filter EO absorption efficiency improves with lower vessels and filter elements have the ability to temperature and/or higher absorbent flow rate. catalyze EO polymerization reactions if stagnant EO EO/water mixtures are highly non-ideal, so in is present for extended periods of time. Periodic scrubber design, Raoult’s Law deviation factors are removal of these particles and periodic changing applied. Scrubbed gas can usually be discharged or cleaning of filters elements (not leaving filters to the atmosphere in accordance with applicable in place with stagnant EO for extended periods of environmental regulatory requirements. time) will minimize the potential for the initiation of A recirculation system using pumps, solution heat a polymerization reaction. There have been multiple exchangers/reactors, and storage vessel(s) are incidents of runaway reactions in EO filters due to required in some but not all applications. rust catalyzed EO polymerization. See Section 5.6 The absorbed EO in the aqueous effluent can be for a discussion of EO filter incidents. recovered in the manufacturing process or can be converted to glycol in a separate reaction system. 6.8 Handling of Vents and Effluent Design of the system for recovering EO through the manufacturing process is specific to the user and Vent Scrubbers is not discussed here. For many EO users, the EO Aqueous systems for absorbing EO in process is reacted to glycol. Although thermal hydrolysis vents are in widespread use in industry. These has been used to react EO to glycol (Figure 6.19), systems can be designed for very high efficiency acid and base reactions are more commonly of EO removal. Vent gas is typically fed to a used. Either strong base or acid is added to the

Figure 6.16.199 Ethylene Oxide Vent Scrubber System

To Atmosphere

EO Vent Scrubber

Reactor Heater Vent from Process

Makeup

Purge Cooler

absorbent stream as a hydrolysis reaction catalyst well as the temperature and composition of the (acids are more effective EO hydrolysis catalysts gas mixture. Because an EO decomposition flame than bases). Phosphoric acid, sulfuric acid, and can transition from a deflagration to a detonation, caustic soda are commonly used for this purpose. the decomposition flame velocity greatly exceeds Hydrochloric acid is typically not used for glycol the normal EO combustion flame velocity, and reaction systems due to the potential to form can be much greater than sonic velocity. Because chlorohydrins. Hydrochloric acid has, however, of the high velocity of the decomposition flame, been used in scrubber systems where the EO the typical forward velocity in a flare header will and dilute acid solution are consumed in the not protect against reverse propagation of a manufacturing process. decomposition flame. To address this, consider It is important to take appropriate steps to avoid installing additional layers of protection in contamination of the process due to backflow from waste gas systems connected to down stream the scrubber systems, especially if acid or base combustion equipment. Such additional design solutions are used. Likewise, liquid EO entering the options for flare systems can include primary scrubber system can result in large exothermic safeguards, such as the velocity section at the reactions, especially in the presence of catalysts flare tip, flame arrestors and redundant safeguards, such as acids or bases. There have been multiple such as IR instrumentation and liquid seals, as incidents where fiberglass EO scrubbers and described below: polypropylene scrubber packing were melted due • Dilution: EO to a flare can be diluted with to overload of an acid catalyzed EO scrubber with methane into a non-decomposible mixture. liquid EO. By using methane instead of an inert gas Design considerations and equipment like nitrogen, the heating value of the stream configuration are specific to the relevant process. can be maintained to meet regulatory Scrubber design may be different for intermittent requirements. Dilution reduces the likelihood processes (for example, filling a storage vessel of a decomposition flame in the header, and is from a railcar) and continuous processes. Reactor typically a “primary” level of protection for an venting accommodates the vessel pressure let EO flare system. down during normal operation and also allows for • Velocity section: The velocity section is a overpressure releases during a process upset. A device used to prevent flashback initiated at process hazard analysis covering both the process the flare tip or in the combustion chamber of a and the scrubber (including interlocks) can be a thermal oxidizer. This device is located directly valuable tool in support of safe operation. at the ignition source or at the inlet of the waste An EO scrubber system may shut down due to gas to the flare or thermal oxidizer. The distance hardware failure or conditions outside the normal between the velocity section and the flare or operating range. Plant design and operating the thermal oxidizer is minimized. In case there procedures anticipating shut down scenarios can is flashback, the outgoing speed required to include instrumentation or response practices to exceed the flashback velocity is maintained by addition of a monitored flow of an inert gas or minimize EO emissions. methane into the waste gas pipe. When this flow Flares falls below a set operational minimum, a gas stream (at a flow greater than the operational Several EO producers and users successfully minimum flow) is introduced into the waste gas use flares to handle EO containing vents. A pipe. The performance of a velocity section critical design consideration for such flares is the depends on the forward speed of the waste prevention of decomposition flame propagation gases exceeding the flashback velocity of the backward from the flare tip into the flare header flammable gases. system (flashback). The flame velocity of an EO decomposition flame can be very high. The • Flame arrestor: A flame arrestor prevents decomposition flashback velocity is, among other propagation of the flame for a limited period things, dependent on the system geometry as of time. Rapid cooling of the flare header can result in the backflow of air from the

Figure 6.20 Schematic of Typical Flaring System

EO Flare

4 Pilots Anti- Flashback Plate Steam Methane to Pilots FLR-002 Primary Ignition—Spark Plugs Backup Ignition—Flame Front Generator EO Vaporization Tubular Flame Vessel Arrester

EO Liquid or Vapor FC

LT LC LAH Methane LAL Diluent LAH LT LI Water Seal LAL TAL Water Seal

Seal TT Water FC TIC Makeup

Steam

*EO flare systems may include some, but not necessarily all of the safety features shown in this diagram

atmosphere into the flare system and possible • IR instrumentation: IR instrumentation is placed formation of a flammable mixture capable of in the waste gas pipe upstream of the flare or ignition by the flare pilot. Properly designed thermal oxidizer. When the IR instrumentation flare tips and flame arrestors are designed to senses a flashback, it activates the feed of prevent this hazard scenario from occurring. If inert gas into the waste gas pipe to extinguish an ignition occurs, however, the flame arrestor the flame. The length of the waste gas pipe can only prevent propagation of the flame for between the IR-instrumentation and the a limited period of time (the gap width of the inert gas inlet is set at a distance sufficient flame arrestor is smaller than the limiting gap to extinguish a flashback. IR instrumentation width of the flammable gas). If continuous is generally implemented as a redundant combustion heats a flame arrestor, it may lose safeguard together with a velocity section or a its effectiveness with regard to flashback; flame arrestor. therefore, the temperature at the flame arrestor • Liquid seal: When the waste gas is introduced is monitored. When the permissible temperature into the liquid seal, it is distributed into is exceeded, an inert gas is introduced into the individual bubbles to prevent a continuous waste gas pipe. The design basis for the inert pathway between the inlet and the outlet gas flow rate is set so the flame at the flame streams (hence avoiding a flow path for a arrestor will be extinguished. flashback). Water or water mixtures are typically Ignition of a non-inerted EO vapor mixture used as a sealing medium. Continuous makeup inside a flare system can result in an EO or level control is often used to maintain design decomposition. The flame front generated by liquid level. Because of the potential for losing a decomposition travels at a very high velocity a liquid seal (for example, blowing the seal out and may not be quenched by a flame arrestor or loss of liquid level), this option provides less designed for a combustion flame (conventional robust protection against flashback than the flame arrestor). In such cases, consider other options discussed in this section. Liquid testing the specific device with regard to EO seals are therefore generally used as redundant decomposition flame propagation. safeguards in conjunction with the use of a velocity section or a flame arrestor.

Thermal and Catalytic Oxidizers 6.9 Miscellaneous Thermal and catalytic oxidizers have been used to Electrical Equipment control EO emissions from some processes. There have, however, been serious incidents involving Electrical area classification Class I, Division 1, several thermal and catalytic oxidizers used at Group B or Class I, Division 2, Group B (National sterilization facilities for control of EO emissions. Electrical Code [3]) are used where atmospheres During 1997, there were explosions at three plants contain or may contain EO under normal or that use catalytic oxidizers for destruction of EO abnormal conditions. Group C may be used if in process vents. Each of the explosions either conduit seals comply with National Electrical damaged or destroyed the catalytic oxidizer. One Code paragraph 501-5(a). Chapter 5 of the of the three incidents occurred during startup National Electrical Code [3] deals with hazardous testing of the oxidizer. In another of the three atmospheres, classifications, and equipment incidents, there was an explosion with a fireball, requirements. Additional references for area and the oxidizer system and the building were classification can be found in API RP500 [4] and destroyed. Subsequent government investigations NFPA 497A [2]. concluded that in all three cases, overfeeding The National Electrical Code requires other of the oxidizer emission control devices resulted equipment, such as lighting fixtures, resistors, and when a high concentration of EO was inadvertently solenoid coils to have normal operating surface sent to the devices. [7] temperatures that do not exceed the ignition temperature of EO. See Section 501 of the National Sewer Systems and Electrical Code [3] for further details. Waste Disposal Facilities If EO is drained (or could inadvertently be Leak Detection Systems drained) to a sewer system, the potential exists Fixed-point combustible gas detectors are often for EO emissions to occur in the sewer system used in petrochemical processing plants. These and treatment facility, and for accumulation of can be calibrated specifically for EO and are flammable vapors in the sewers, lift stations, often used to trip deluge systems in plants. Note, and waste water storage vessels. Installation of however, that these detectors are generally not online analyzers, nitrogen purges, and emission designed for monitoring for industrial hygiene control devices may be appropriate in such cases. purposes. The low concentrations of allowable Because of the combustibility of EO vapors in air, exposure and the low Reportable Quantity for there is significant potential for an explosion in a environmental releases make more sensitive leak closed sewer system. Consider using a design with detection equipment desirable for EO processes. open flumes and/or open top wastewater vessels in Gas Chromatograph-based leak detection systems order to minimize the potential for fire or explosion. sensitive to 1 ppm EO are in use both in process (The potential for fire exists if the EO is not diluted plants and laboratories where EO may be present. with water with a ratio of greater than 100:1.) These systems generally have multiple fixed Wastewater containing low concentrations (less sample locations connected to a single analyzer. than 1000 ppm) of EO has been successfully Electrochemical sensors have also been used, but disposed of in biological waste treatment facilities are not EO specific and are subject to interference after proper acclimation of the system. Check from other chemicals. applicable environmental regulatory requirements before sending EO to a disposal facility. See Section 4.2 for a discussion of biodegradation of EO.

Sampling Systems Figure 6.21 EO Sampling System There are a number of design considerations for EO sampling systems. Minimizing EO leaks or personnel exposure is an important starting point. An effective system design allows capture of a representative sample of EO without releasing EO to the environment or exposing the sample collector. Potential for personnel exposure to EO during sample preparation and analysis can be minimized by use of a laboratory hood. Dry- disconnect tubing fittings can also be used for the connection from the sample tubing to the cylinder. Residual EO in the sample cylinder can be managed by purging the sample connection with nitrogen and depressuring the sample system to a vent collection system. Using a vacuum water jet system to evacuate the sample cylinder prior to disconnecting is another effective technique. A well-designed system seeks to avoid overfilling the sample cylinder with liquid. Overfilling results in the potential for cylinder overpressure from liquid expansion. For this reason, typical EO sample cylinders are stainless steel with an internal dip tube to prevent overfilling with liquid. The cylinder is filled while positioned vertically with the dip tube at the top, and only the valve with the dip tube connects to the sample system. To reduce the temperature of the EO in the sample cylinder, store cylinders under refrigeration (before and during sample analysis) until the remaining EO is returned to process use or disposed of in accordance with applicable environmental regulatory requirements.

7.0 Personnel Exposure

7.1 Introduction 7.3 Other Exposure Standards/ This Chapter provides an overview of issues related Recommendations for to personnel exposure to EO including selection Ethylene Oxide of personal protective equipment for use in EO Immediately Dangerous to Life and Health service. This Chapter focuses on the requirements of the OSHA EO standard published in the Federal The National Institute for Occupational Safety Register on June 22, 1984, and amended on April and Health (NIOSH) has quantified exposures to 6, 1988. The regulation, 29 CFR 1910.1047, should be approximately 400 toxic chemicals that could be consulted for specific requirements. “Immediately Dangerous to Life and Health” (IDLH). The IDLH exposure value for EO is 800 ppm. The official definition of IDLH is given in 30 CFR 11.3. The 7.2 OSHA Standard for Ethylene Oxide IDLH concentration represents an estimate of the Coverage maximum concentration of a substance in air from which healthy workers can escape without loss of The OSHA regulation applies to any worker who life or irreversible health effects under conditions may be exposed to EO. Operations associated of a maximum 30-minute exposure time. with the production, use, transportation, storage, loading or unloading of EO are covered under Emergency Response Planning Guidelines this regulatory standard. The only exception to The American Industrial Hygiene Association (AIHA) this coverage is the processing, use, or handling has recommended Emergency Response Planning of products containing EO where objective, Guidelines (ERPGs) for a number of substances. reasonably reliable data demonstrates that the For EO, AIHA has recommended an ERPG-3 product is not capable of releasing EO in airborne of 500 ppm, which is “the maximum airborne concentrations at or above the action level under concentration below which it is believed nearly expected conditions of processing, use, or all individuals could be exposed for up to 1 hour handling. Records of the objective data must be without experiencing or developing life threatening maintained if the exemption is used. health effects.”[1] Exposure Limits The ERPG-2 of 50 ppm for EO is “the maximum OSHA’s Permissible Exposure Limits, or PELs, are airborne concentration below which it is believed the following: nearly all individuals could be exposed for up to 1 hour without experiencing or developing • 1 ppm in air as an 8-hour time weighted average irreversible or other serious health effects or (TWA) concentration symptoms that could impair an individual’s ability • 5 ppm in air as a 15-minute time weighted to take protective action.” [1] average (TWA) concentration - excursion limit There is no specified ERPG-1 for EO, the “maximum (EL) airborne concentration below which it is believed There is also an action level (AL) at 0.5 ppm as an nearly all individuals could be exposed for up 8-hour TWA, which triggers certain compliance to 1 hour without experiencing more than mild, activities such as exposure monitoring, medical transient adverse health effects or without surveillance, and training. The excursion limit is perceiving a clearly defined objectionable odor.” 5 ppm. Acute Exposure Guideline Levels Acute Exposure Guideline Levels (AEGL) for EO were proposed by a National Academy of Sciences committee in September 2006, as set out in Table 7.1 below.

Table 7.1 AEGL Values for Ethylene Oxide

Classification 10 minute 30 minute 1 hour 4 hour 8 hour Endpoint

AEGL-1 No values derived (Nondisabling)

AEGL-2 80 ppm (144 80 (144) 45 (81) 14 (25) 7.9 (14) Developmental (Disabling) mg/m3) toxicity and neurotoxicity

AEGL-3 (Lethal) 360 ppm (648 360 (648) 200 (360) 63 (113) 35 (63) Lethality mg/m3)

AEGL-1 is the airborne concentration of a substance Regulated Areas above which it is predicted that the general Regulated areas must be established wherever population, including susceptible individuals, could occupational exposure may exceed the PELs. experience notable discomfort, irritation, or certain Those areas must be marked and access limited to asymptomatic, non-sensory effects. However, the authorized persons. Warning signs must be posted effects are not disabling and are transient and around regulated areas stating: reversible upon cessation of exposure. AEGL-2 is the airborne concentration of a Figure 7.1 OSHA Warning for substance above which it is predicted that EO Regulated Areas the general population, including susceptible individuals, could experience irreversible or other serious, long-lasting adverse health effects, or an impaired ability to escape. AEGL-3 is the airborne concentration of a substance above which it is predicted that the general population, including susceptible individuals, could experience life-threatening health effects or death. Data were available for deriving AEGL-2 and -3 values. Values for AEGL-1 were not derived because the odor threshold and concentrations causing mild sensory irritation would be above the AEGL-2 levels causing “disabling effects.” [2]

Exposure Monitoring Methods of Compliance Initial monitoring is required to determine airborne Where the TWA or excursion limit is exceeded, the concentrations of EO to which employees are employer must establish and implement a written exposed. If concentrations are above the OSHA program to reduce employee exposure to or below action level of 0.5 ppm, periodic monitoring is also the TWA and to or below the excursion limit by required. Additional monitoring may be required if means of engineering and work practice controls, there are changes in process, production, control as required by paragraph (f)(1) of Section 1910.1047, equipment, personnel, or work practices that may and by the use of respiratory protection where result in new or additional exposures. The OSHA required or permitted under this Section. regulation requires employees to be notified of any The compliance program must include a schedule monitoring results within 15 days of receipt of the for periodic leak detection surveys and a written results. plan for emergency situations as specified in paragraph (h)(i) of the OSHA regulation.

OSHA recognizes that engineering controls EO that do not require subsequent analysis, with are generally not feasible for certain activities, detection limits in the low ppm range. Portable including loading and unloading of railcars, vessel electrochemical EO detector/alarms and passive cleaning, and maintenance and repair activities. In badge-type monitors for EO exposure are also cases where engineering controls are not feasible available. to prevent exposure above either of the PELs, Appendix D of the OSHA EO standard describes NIOSH-approved respirators must be worn. See available methods of sampling and analysis. the Respiratory Protection discussion in Section 7.5 The employer has the obligation of selecting a below for more information on respirator selection. monitoring method which meets the accuracy and precision requirements of the standard under the Medical Surveillance Program employer’s field conditions. The employer must provide annual medical surveillance for employees who are or may be exposed to EO at or above the Action Limit, without 7.5 Personal Protective Equipment regard to the use of respirators, for at least 30 Ethylene Oxide Exposure days during the year. Specific requirements for surveillance and medical record retention are When there is potential for exposure to EO included in the OSHA standard [3]. vapors or liquid, it is important to use the proper protective equipment. EO can be trapped against Training the skin and can cause severe chemical blistering Information and training must be provided to any and burns, which take a long time to heal. When personnel who are potentially exposed to EO at or released, EO liquid will quickly change to vapor. above the action limit or excursion limit. Topics for If protective clothing with open sleeves and legs training are specified in the OSHA standard. is worn, this vapor can readily get underneath the clothing and result in burns. EO can also penetrate Product Exemptions protective clothing seams, so it is important to consider suit construction as well. Products made from EO or containing EO are exempt from the standard if objective data shows Even dilute EO solutions can result in severe they will not release EO at or above the action level chemical burns if the skin remains exposed to the during normal handling or use. solution. Figure 7.2 shows a chemical burn resulting from 90 minutes of exposure to a dilute EO-water Written Emergency Plan mixture absorbed into leather shoes. An emergency plan must be developed for each workplace where there is a possibility of an Figure 7.2 Chemical Burn Resulting emergency. The employer must have a means from Low Concentration of of promptly alerting affected employees of an EO in Water emergency occurrence.

Recordkeeping The standard contains requirements for retention of medical and exposure records. Other provisions of the standard also contain recordkeeping requirements.

7.4 Measuring Exposure A number of methods are available for monitoring exposure to EO. Many of these involve the use of charcoal tubes and sampling pumps, followed by analysis of the samples by gas chromatography. There are also indicator tube systems specific to

Eye Protection — Durability in light of repeated contamination and decontamination Splashes of EO into the eye can cause severe eye irritation with corneal injury. The OSHA EO standard — Flexibility/pliability to allow users to perform recommends wearing goggles at all times in needed tasks those areas where there is a risk of splashes from — Heat/cold resistance, such that the material liquid EO. Face shields (visors) provide additional maintains its protective integrity and protection when performing any activity in which flexibility under hot and cold extremes there is a risk of splashes from liquid EO. — Flame resistance/ability to self extinguish In the non-mandatory Appendix A of the standard, where a fire hazard may be present (such as OSHA recommends that contact lenses not be in the event of a flash fire). For EO service, worn where EO exposure potential exists. Where consider whether a flash oversuit or an EO contact with EO can occur, consider the use of resistant suit incorporating flash protection contact lenses carefully in the context of overall may be appropriate. personal protective equipment policies and — Seam quality, such that that garment seams practices. in the clothing are constructed to provide Protective Clothing the same physical integrity as the garment material There are many important factors to consider when selecting appropriate personal protective Many protective clothing materials in common equipment. These can be broadly grouped into use are permeable to or attacked by EO. Clothing two categories: material chemical resistance and contaminated by EO must either be discarded material physical properties. or decontaminated before reuse. Clothing must be discarded if it has been degraded or has • Material chemical resistance: ideally, the chosen absorbed EO. It is also important to note that EO material(s) resists permeation, degradation, and and aqueous mixtures permeate leather, including penetration by the respective chemicals. leather boots (see Figure 7.2 above). Accordingly, — Permeation breakthrough time is the leatherwear contaminated with liquid EO must most important factor used to assess be discarded because decontamination is not material chemical compatibility. The rate of practical. permeation is a function of several factors Materials proposed for use in protective equipment such as chemical concentration, material that are not known to be EO-resistant should first thickness, humidity, temperature, and be tested to establish their suitability. Test data pressure. may be generated from a number of sources, — Degradation involves physical changes in a such as materials manufacturers, equipment material resulting from chemical exposure, manufacturers, EO producers or users, researchers, use, or ambient conditions (such as sunlight). contract laboratories, or others. Published, peer- The most common observations of material reviewed data is also available to help evaluate the degradation are discoloration, swelling, loss suitability of the material for EO use. of physical strength, or deterioration. When evaluating test data, be aware that data may — Penetration is the movement of chemicals be of varying quality or reliability. Whether the data through zippers, seams, or imperfections in is well-documented or published, derived from a protective clothing material. multiple sources, has been subject to repeated • Physical properties: other factors to consider testing, has been generated from an independent include evaluating the material for its testing agency, and is recent or updated are all factors to consider. If an ASTM test method is — Strength, such that it can withstand the available, there may be data obtained from tests physical tasks at hand performed in accordance with standard ASTM — Resistance to tears, punctures, cuts, and abrasions

methods. Note that qualitative ratings of”poor,” Respiratory Protection “good,” or “excellent” give little to no indication If the presence of EO in excess of exposure limits of how a material may perform against various is expected or detected, OSHA regulations dictate chemicals and with regard to the specific needs of that respiratory protection consisting of a NIOSH- EO service. approved respirator must be used. The OSHA EO EO permeation data for clothing, glove, and boot standard, 29 CFR 1910.1047, provides minimum materials are presented in Tables 7.3, 7.4, and 7.5 standards for respiratory protection for airborne EO below. (Table 7.2).

Table 7.2 OSHA Minimum Standards for Respiratory Protection for Airborne Ethylene Oxide

Airborne EO Concentration or Minimum Required Respirator Type Condition of Use

Less than or equal to 50 ppm Full facepiece with EO-approved canister, front or back mounted

Less than or equal to 2,000 ppm (A) Positive-pressure supplied air equipped with full facepiece, hood or helmet, or

(B) Continuous-flow supplied air (positive pressure) equipped with hood, helmet or suit

Above 2,000 ppm or unknown (such as (A) Positive-pressure self contained breathing apparatus (SCBA), or in emergencies) (B) Positive-pressure full facepiece supplied air respirator equipped with an auxiliary positive-pressure self-contained breathing apparatus

Firefighting Positive-pressure self-contained breathing apparatus (SCBA), equipped with full face-piece

Escape Any respirator described above

IMPORTANT NOTE for Tables 7.3, 7.4, and 7.5: Data and characterizations of performance are provided as reported by materials manufacturer, from published literature or government sources, or from other databases. Data entered as “EOIC 1990 Data” is from materials permeation testing sponsored by the Ethylene Oxide Industry Council (now the Ethylene Oxide/Ethylene Glycols Panel) and published by Stull, Pinette, and Green (1990). The data displayed is for information purposes only; the data displayed does not constitute an endorsement or recommendation of any particular material of construction or PPE manufacturer. Note that some materials have been tested more than once by more than one party, as indicated by multiple results. Manufacturers may change materials selection or formulation at any time which may change breakthrough times and other performance characteristics of the PPE. Before making any PPE selection, contact the supplier for specific product information, suitability for use in EO service, and current information on test data regarding the manufacturer’s products. “NS” means not specified in test data. PPE names and/or descriptions may be trademarked by the manufacturer.

Table 7.3 Ethylene Oxide Permeation Data for Clothing MATERIALS - PROTECTIVE CLOTHING Permeation Breakthrough Time: >480 minutes (See Important Note for Tables 7.3, 7.4, and 7.5, above)

Material Gas/Liquid Breakthrough Time Additional Comments (Manufacturer) (Minutes)

EOIC Materials/PPE Gov’t 1990 Manufacturer Data Data1 Data2

Barricade® (DuPont®) Gas >480 No longer manufactured

Liquid >480 No longer manufactured

Challenge Gas >950 5100®(ChemFab®)

Chemrel Max® NS >480 The personal (Chemron UK) protective suit is now manufactured by Draeger.

CPF-3® (Kappler/ Gas >480 >480 DuPont®) Liquid (11°C, 0°C) >480

CPF-4® (Kappler/ Gas >480 305 DuPont®) Liquid (11°C, 0°C) >480

Responder® Gas >480 >480 (Kappler/DuPont®)

Responder®/Blue Gas >480 Max (LifeGuard/MSA)

(continued on page 74)

Table 7.3 Ethylene Oxide Permeation Data for Clothing (continued from page 73)

Material Gas/Liquid Breakthrough Time Additional Comments (Manufacturer) (Minutes)

EOIC Materials/PPE Gov’t 1990 Manufacturer Data Data Data

Responder CSM® Gas >480 (Kappler/DuPont®)

Responder Plus® Gas >480 (Kappler/DuPont®)

Trellchem® HPS >480 www.cdc.gov/niosh/ncpc/ (Trelleborg) ecpc.html In supplement to NIOSH Guide to Chemicals.

Tychem® 9400 Gas >480 No longer manufactured (DuPont®) Liquid >480 No longer manufactured

Tychem® 10,000 Gas >480 No longer manufactured (DuPont®) Liquid >480 No longer manufactured

Tychem® BR Gas >480 and Tychem® LV (DuPont®) Liquid (0°C) >480

Tychem® Reflector Gas >480 (Kappler /DuPont®) Liquid >480

Tychem® Responder Gas >480 (Kappler/DuPont®)

Tychem® TK Gas >480 (DuPont®) Liquid (0°C) >480

Mixture: 10% >480 EO in HCFC 124

(continued on page 75)

Table 7.3 Ethylene Oxide Permeation Data for Clothing (continued from page 74) MATERIALS – PROTECTIVE CLOTHING Permeation Breakthrough Time: 60 - <480 minutes (See Important Note for Tables 7.3, 7.4, and 7.5, above)

Material Gas/Liquid Breakthrough Time Additional Comments (Manufacturer) (Minutes)

EOIC Materials/PPE Gov’t 1990 Manufacturer Data Data Data

4H® >240 Forsberg, K et al. Quick selection guide to chemical protective clothing. 3rd edition. Van Nostrand Reinhold 1997.

Butyl rubber >240 Forsberg, K et al. Quick selection guide to chemical protective clothing. 3rd edition. Van Nostrand Reinhold 1997.

Cloropel™ – Blue NS 2) 118, Rated by ILC Dover Chemical CPE (ILC Dover) 375 manufacturer Compatibility Chart. as excellent (Little or no effect)

CPE® (Kappler/ Gas 80 DuPont®)

MSA BETEX Butyl/ NS 165 No longer manufactured Neoprene

PE/EVAL (4H®-Safety >240 www.cdc.gov/niosh/ 4 Company and ncpc/ecpc.html SilverShield®-Siebe North Company)

Responder Plus® Liquid >180 (Kappler/DuPont®)

TeamMaster – Umex NS >60 to 120 (Draeger)

TeamMaster Pro NS >60 to 120 –Himex® (Draeger)

Tychem® F (DuPont®) Gas 65

Tychem®Responder Liquid (11° C, 0°C) >180 >180 (Kappler/DuPont®)

Tychem® TK Liquid (-70°C) >180 (DuPont®)

(continued on page 76)

Table 7.3 Ethylene Oxide Permeation Data for Clothing (continued from page 75)

Material Gas/Liquid Breakthrough Time Additional Comments (Manufacturer) (Minutes)

EOIC Materials/PPE Gov’t 1990 Manufacturer Data Data Data

Ultra-Pro Gas >180 Ultro Pro was replaced Commander (Mar- with TK500 series, Mac Manufacturing now manufactured by Inc®) DuPont.

WorkMaster – Umex NS >60 to 120 (Draeger)

WorkMaster – Himex NS >60 to 120 ® (Draeger)

MATERIALS – PROTECTIVE CLOTHING Permeation Breakthrough Time: Immediate - <60 minutes (See Important Note for Tables 7.3, 7.4, and 7.5, above)

Material Gas/Liquid Breakthrough Time Additional Comments (Manufacturer) (Minutes)

EOIC 1990 Materials/PPE Data Manufacturer Gov’t Data Data

Butyl rubber Gas 44-52 (LifeGuard)

Challenge® 5200 NS 27-35 (ChemFab)

CPF® –2 (Kappler / Gas Immediate DuPont®)

Fairprene® NS 51,158 No permeation data Neoprene available from the materials manufacturer.

N-44 Neoprene NS 31 (Pioneer-acquired by MAPA® Professional)

Natural rubber <60 Forsberg, K et al. Quick selection guide to chemical protective clothing. 3rd edition. Van Nostrand Reinhold 1997.

Neoprene <60 Forsberg, K et al. Quick (DuPont®) selection guide to chemical protective clothing. 3rd edition. Van Nostrand Reinhold 1997.

(continued on page 77)

Table 7.3 Ethylene Oxide Permeation Data for Clothing (continued from page 76)

Material Gas/Liquid Breakthrough Time Additional Comments (Manufacturer) (Minutes)

EOIC 1990 Materials/PPE Data Manufacturer Gov’t Data Data

Nitrile rubber <60 Forsberg, K et al. Quick selection guide to chemical protective clothing. 3rd edition. Van Nostrand Reinhold 1997.

Polyethylene <60 Forsberg, K et al. Quick selection guide to chemical protective clothing. 3rd edition. Van Nostrand Reinhold 1997.

Polyurethane (ILC 1) NS 2) NS 2) 29, 65 1) Not ILC Dover Chemical Dover) recommended Compatibility Chart. by materials manufacturer for EO use (severe effect)

Polyvinyl chloride <60 Forsberg, K et al. Quick selection guide to chemical protective clothing. 3rd edition. Van Nostrand Reinhold 1997.

Saranex™ <60 Forsberg, K et al. Quick (Dow Chemical selection guide to Company) chemical protective clothing. 3rd edition. Van Nostrand Reinhold 1997.

Saranex™ NS 6

Tychem® 7500 Gas 53 minutes 75 (DuPont®)

Tychem ®QC Gas/Vapor Immediate (DuPont®) (less than 10 minutes)

Tychem® SL Gas/Vapor Immediate Immediate (DuPont®)

Tyvek®- NS Immediate Polyethylene (<1) coated (DuPont®)

Viton® (DuPont® <60 Forsberg, K et al. Quick Dow Elastomers®) selection guide to chemical protective clothing. 3rd edition. Van Nostrand Reinhold 1997.

MATERIALS - PROTECTIVE GLOVES Permeation Breakthrough Time: > 480 minutes (See Important Note for Tables 7.3, 7.4, and 7.5, above)

Material Gas/Liquid Breakthrough Time Additional Comments (Manufacturer) (Minutes)

EOIC Materials/PPE Gov’t 1990 Manufacturer Data Data Data

Butyl Rubber (North® Gas >480 Safety Products)

Silvershield®(North® NS/Gas >480 >480 Safety Products)

MATERIALS – PROTECTIVE GLOVES Permeation Breakthrough Time: 60 - < 480 minutes (See Important Note for Tables 7.3, 7.4, and 7.5, above)

Material Gas/Liquid Breakthrough Time Additional Comments (Manufacturer) (Minutes)

EOIC Materials/PPE Gov’t 1990 Manufacturer Data Data Data

4H® Gas >240 No longer (Ansell Occupational manufactured Healthcare® )

878 Butyl® (Best®) Gas 189 189

A-15 Nitrile (Pioneer NS 195, – acquired by MAPA® >315 Professional)

Butyl Chemical NS 173 Protective – Styles CP-7, CP7F, CP- 14, CP-14R, CP-25, IB-35 (Guardian Manufacturing®)

Barrier (Ansell Gas 234 Occupational Healthcare®)

Silver Shield®/4H® NS - 21°C >240 (North® Safety Products)

Tychem® TK Gas >180 (DuPont®)

(continued on page 79)

Table 7.4 Ethylene Oxide Permeation Data for Gloves (continued from page 78) MATERIALS – PROTECTIVE GLOVES Permeation Breakthrough Time: Immediate - < 60 minutes (See Important Note for Tables 7.3, 7.4, and 7.5, above)

Material Gas/Liquid Breakthrough Time Additional (Manufacturer) (Minutes) Comments

EOIC 1990 Materials/PPE Gov’t Data Manufacturer Data Data

65NFW Natural Gas 1 Rubber (Best®)

6780 Neoprene Gas 21 21 (Best®)

890 Viton® (Best®) Gas 48 48

CHEM-PLY™/N-440 NS 45 neoprene (MAPA® Professional)

Composition Not tested by 29-865 neoprene, manufacturer for 37-145 nitrile (Ansell use in EO service. Occupational Healthcare®)

Hustler™ 725R PVC Gas 1 1 (Best®)

N-44 Neoprene NS 31 (Pioneer-acquired by MAPA® Professional)

Natural Rubber NS 3, 5 Surgical (Dayton®)

Neoprene Chemical 40 Protective (Guardian Manufacturing®)

Neoprene Ultraflex 32 Gas Degradation (Best®) rating over time -operations use; excellent at 5 min, 30 min, 60 min, 240 min). Permeation data: 7 minutes, (heavy exposure) Not tested in limited exposure.

(continued on page 80)

Table 7.4 Ethylene Oxide Permeation Data for Gloves (continued from page 79)

Material Gas/Liquid Breakthrough Time Additional (Manufacturer) (Minutes) Comments

EOIC 1990 Materials/PPE Gov’t Data Manufacturer Data Data

Nitrile (Ansell (1) Gas; (1) minimal (4) Not tested Occupational (2) Splash splash by vendor for Healthcare®) Gas protection use with EO for routine tasks; (2) 60-84 minutes; (3) <4 to 4

Nitri-Solve® 727 Nitrile Gas 17 17 (Best®)

Nitty Gritty® 65NFW Gas 1 minute (Best®)

PVC Model G3112 Gas 4-8 Not tested by (North® Safety manufacturer for Products) use in EO service.

Stansolv® A-14 nitrile NS 32 (non- (MAPA® Professional) normalized breakthrough)

Stansolv® AK-22 No test data (MAPA® Professional) available from vendor

Stanzoil®/Milled Gas 28-38 Neoprene (Pioneer- acquired by MAPA® Professional )

Ultraflex 22R Nitrile Gas 12 12 (Best®)

Table 7.5 Ethylene Oxide Permeation Data for Boots MATERIALS – PROTECTIVE BOOTS (See Important Note for Tables 7.3, 7.4, and 7.5, above)

Material Gas/ Breakthrough Time Additional Comments (Manufacturer) Liquid (Minutes)

Materials Boots Vendor Gov’t Manufacturer Data Data Data

Rubber Bunker Manufacturer notes it Boots, vulcanized, meets NFPA 1971 Standard hand-crafted ozone on Protective Ensemble resistant (FireTech™- a for Structural Fire division of LaCrosse® Fighting, 2000 Edition. Safety and Industrial)

Firewalker (Ranger™- According to Total Fire Group™) manufacturer there is no EO permeation data available for the fabric that is used as a liner.

Hazmax™ (OnGuard NS 180 minutes Tested to meeting the Industries) NFPA 1991, 2005 Edition Boot Requirements

Steel Toe Neoprene Manufacturer notes Chemical Resistant “Chemical Resistance: Boots (Tingley Rubber Animal fats and blood, Corporation) oils, certain acids, alcohols, alkalies, and certain solvents.”

Neoprene (Tingley Manufacturer notes Rubber Corporation ) “Chemical Resistance: Fats, certain acids, hydrocarbons, caustics, and other chemicals.”

HazProof® (Tingley NS Actual Rubber Corporation) breakthrough time: >60 minutes; Normalized breakthrough time: >60 minutes

Triple Dipped Manufacturer notes Neoprene (Servus NFPA 1971 (2000 edition) Fire) certified.

1 Gathered from American Chemistry Council, Ethylene Oxide Industry Council sponsored research by Stull, Pinette, and Green (1990). 2 Collected from the Material manufacturer or PPE manufacturer.

8.0 Equipment Preparation and Maintenance

8.1 Introduction appropriate wastewater treatment system. If EO polymer is present, refer to the discussion below, When equipment in EO service must be opened for “Special Issues with Ethylene Oxide Polymer.” testing, inspection or repairs, facility requirements Care should be taken that hydrates are not formed applicable to handling of flammable and toxic during the water washing, since the melting points liquids and gases are strictly observed. All EO is of EO/water mixture can be as high as 52°F (11.1°C) removed from the system and either returned to (see Table 2.2 in Chapter 2). Dispose of rinse the process or disposed of in accordance with water in accordance with applicable regulatory federal, state, and local regulations. requirements and in a manner that is protective Storage tanks and lines are thoroughly cleaned of personnel. (It should be noted that even dilute and purged with dry nitrogen before equipment is solutions of EO in rinse water have caused severe placed in or returned to EO service. Contaminants chemical burns. See Chapter 7). Once equipment such as oxygen, water, and cleaning chemicals are is substantially free of liquid EO, steam purging completely removed to avoid dangerous reactions. can be used to remove traces of EO to allow for equipment entry. While steam purging, sudden 8.2 Preparation for Inspection or condensing of steam may produce a vacuum in Maintenance equipment that is not rated for vacuum service.) Prior to entry, the equipment is isolated from the Preparations for Entry process and from potential sources of hazard. Where applicable, the user must follow the Atmosphere is tested for the presence of EO. requirements of the OSHA confined space standard Levels of EO must be low enough so personnel (29 CFR 1910.146). Equipment is cleaned and can safely enter. Persons entering equipment, purged of EO before beginning any maintenance vessels, or any confined space that has been work. If it is impractical or not possible to reduce in EO service are equipped with appropriate airborne concentrations in and around the respiratory protection (see Section 7.5) unless it equipment below 1 ppm, OSHA regulations require is demonstrated that the atmosphere inside the that appropriate personal protective equipment be equipment, vessel or confined space does not worn. See Section 7.5 for further discussion. The present a hazard and measured EO levels do not use of a gas detector for measuring ppm ranges of otherwise require respiratory protection under EO is required by federal regulations to verify that OSHA. equipment is free of EO before allowing personnel to enter equipment. [29 CFR 1910.146 (OSHA Special Issues with EO Polymer confined space entry regulation) and 29 CFR In systems storing pure EO, it is common for 1910.1047 (EO-specific OSHA regulation)]. polymer to form and to accumulate gradually, especially where the EO is relatively stagnant. An important prerequisite to maintenance work Polymer can retain EO after washing, and the on EO equipment is the development and use of polymer can gradually release the retained EO a robust safe work plan that educates all affected even after the equipment initially tests free of EO. personnel regarding applicable hazards. An To address this scenario, one effective practice effective work plan also includes other relevant is to wait several hours after the initial purging components, such as an explanation of the and rinsing steps and retest before opening the importance of using proper personal protective storage system to the atmosphere. equipment, of observing applicable safety precautions in each work task, and of observing Low molecular weight polymer can generally other measures appropriate to working with EO. be removed from EO by steaming or washing with hot water. Before using hot water or steam Equipment being worked on is thoroughly drained – both of which would be reactive with EO – to and blown free of liquid EO with nitrogen. The further decontaminate equipment, the equipment equipment is then washed with cool water to should be substantially free of EO. Adequate remove residual liquid EO and drained to an

isolation of EO systems to be cleaned will help in making such specifications and in performing prevent introduction of water or steam into other the cleaning. A variety of chemical cleaning equipment still containing EO. processes are available for preparing metal High molecular weight polymer is generally surfaces for EO service depending on what surface removed by physical means, such as high pressure contaminants are present, including: water blasting. • Alkaline or detergent degreasing, followed by Polymer residues can contain residual EO. The thorough rinsing. residues may be flammable and may present a • Acid cleaning, if the metal is carbon steel. The health hazard, and EO may continue to evolve from presence of both carbon and stainless steel polymer. If polymer cannot be removed by warm creates complexities that suggest the use water washing, personnel entering a vessel to or consultation with appropriately qualified undertake physical cleaning should be provided engineers before undertaking acid cleaning. with appropriate personal protective equipment. Acid cleaning is followed by thorough rinsing of OSHA regulations require respiratory equipment the equipment. if free EO levels cannot be reduced to less than Acid-based cleaning often uses EDTA or citric acid. 1ppm. It may or may not be preceded by a degreasing step. If the system to be cleaned contains mild Mothballing steel, a neutralization and passivation step is Equipment which has been in EO service, but is performed. Sodium nitrite is typically used for being removed from service, is decontaminated passivation. The system is thoroughly flushed by washing or steam cleaning to less than 1 ppm with water (oxygen-free, if available) and dried by of EO. Before washing or steam cleaning, such blowing with dry, hot nitrogen. Equipment is left equipment is disconnected or blinded from “live” under nitrogen pressure until ready to receive EO. equipment. Consider maintaining carbon steel Failure to adequately passivate or to keep material equipment under a nitrogen blanket to prevent rust under nitrogen blanket will result in significant rust formation. formation.

CAUTION: 8.3 Preparation of Internal Surfaces EO is highly reactive. It is extremely important Foreign material on internal surfaces of EO- to remove all residues of cleaning chemicals containing equipment can cause slow self- because EO may react violently with them polymerization of EO, resulting in a buildup of after the equipment is returned to EO service. the polymerized material on those surfaces. This self-polymerization can be minimized by removing The effectiveness of a particular chemical cleaning foreign matter such as welding slag, loose debris, procedure can be evaluated in advance using a and rust on internal surfaces prior to putting test sample of the same metal as the surfaces to equipment into service. be cleaned. Cleaning can be accomplished by shot or grit blasting, or by chemical methods. Shot blasting 8.4 Leak Repair Clamps creates dust and debris, which is then removed. Clamp-on or bolt-on, split body style leak repair It is helpful to maintain a dry air purge during clamps have been used for temporary mitigation blasting. Purging the equipment as soon as of small EO leaks from piping, valves, and vessels. possible after the blasting helps prevent rust Leak repair clamps can often be obtained “off-the- formation. Where equipment surfaces, such as shelf,” or they can be engineered to fit, depending pipework, are inaccessible to blast cleaning, on the application. The user must evaluate the chemical methods may be used. relative risk of using clamps. Many common leak Chemical cleaning may involve the use of repair sealants are not suitable for use in EO hazardous materials, and it may damage service due to the potential for chemical reactivity. equipment if not properly specified and performed. The use of a qualified cleaning specialist is helpful

Prior to the use of a sealant in a leak repair clamp, To help prevent polymer formation, include determine its potential reactivity with EO. This can consideration of purging spare and offline piping be effectively accomplished by testing for reactivity and equipment as part of the maintenance with EO in a calorimeter. If a sealant is reactive with program. EO, there is the potential to generate a hot spot due to the heat of reaction, which could initiate an 8.6 Equipment Commissioning EO decomposition reaction. Because EO can be an aggressive solvent, the effectiveness and long- Before returning equipment to service after term durability of leak repair sealants to be used maintenance, leak testing is conducted. This in EO service should be determined before use. is commonly done by closing, capping, and Testing can help make this determination. plugging all bleed valves with all flange covers tight. Equipment and piping is pressurized with As with any moving stem valve, valves in EO service nitrogen to a pressure at or near the normal may experience fugitive emissions leaks. It is operating pressure of the equipment. All new or generally preferable to avoid leak repairs while a disturbed flange connections and other fittings can system is online. If an EO valve packing gland has be leak tested while holding the pressure for an to be repaired by drilling, tapping, and installing a appropriate period. sealant injection fitting for injection of a sealant, carefully control the localized frictional heat Some techniques commonly used to detect leaks generated during the drilling on the valve body before putting EO equipment into service include: to help prevent approaching the decomposition • Soap test temperature of EO. • Helium leak test using a portable mass spectrometer 8.5 Preventive Maintenance • Vacuum test (on equipment rated for vacuum A routine preventive maintenance program for EO service) equipment helps achieve proper operability of the Detected leaks are repaired before introducing system. Key components for internal inspections EO into the system. After introducing EO into the include checking the integrity of monitoring system, all flange connections are rechecked as equipment and detecting polymer formation in soon as possible using a gas detector capable of the system. Other areas of focus for an inspection detecting EO at ppm levels. program are no flow or low flow zones in a piping network and small bore instrumentation tubing, both of which have the potential for polymer buildup. Nozzles for instrumentation and inlets to pressure relief valves are also generally included as areas for inspection as part of a routine maintenance program.

9.0 Transportation and Unloading Operations

9.1 Introduction 9.4 Railcars This Chapter provides a basic overview of Design – General transportation and unloading operations for EO. DOT requires that EO be transported in Class 105-J Note that the use of dedicated EO unloading tank cars. All tank cars used in EO service must facilities is extremely important to help avoid have a tank pressure rating of at least 300 psig contamination of EO with other chemicals. by July 1, 2006, at the latest. Most EO tank cars in service already meet this requirement. 9.2 Emergency Response Regulations also require EO tank cars to have a Telephone Numbers reclosing pressure relief device set to function In the event of an emergency involving an EO at 75 psig. These requirements are specified in shipment, contact the emergency response 49 CFR 173.323. DOT class 105-J railcars meeting telephone number found on the shipping papers the required 300 psi tank test pressure are or the emergency assistance numbers provided constructed from fusion welded carbon steel with in the shipper’s MSDS. CHEMTREC® (Chemical 9/16” minimum plate thickness, and must have an Transportation Emergency Center) was established approved thermal protection system. as a public service hotline for fire fighters, law An EO tank car is designed for loading and enforcement personnel, and other emergency unloading from the top only with no bottom responders to obtain information and technical fittings. The potential for leakage from damaged assistance for emergency incidents involving tank fittings is greatly reduced in a transportation chemicals and hazardous materials. CHEMTREC incident when protected top fittings and no bottom provides a 24-hour emergency telephone number fittings are used. An EO railcar (Type DOT 105-J) on shipping documents that can be called in is equipped with two eduction pipes/unloading the event of an emergency involving hazardous connections, one vent for loading or vapor materials. connection, a gauging device, a reclosing pressure For additional assistance or information relief device (safety valve), and a thermometer well within the United States call CHEMTREC: (thermowell). All railcars are equipped with a sump (800) 424-9300 or (202) 483-7616. for the eductor or discharge tubes. Some railcar tank bottoms are designed to slope towards the For additional assistance or information within sump. The sump aids in minimizing the remaining Canada, call: CANUTEC at (613) 996-6666, collect EO heel after the railcar is unloaded. (or *666 via cellular phone within Canada). For additional information regarding shipment to and Design – Insulation from Canada see Section 9.8. A typical insulation system found for an EO railcar consists of 0.65 inches of ceramic fiber surrounding 9.3 Ethylene Oxide Classification the tank shell, covered with 4-inches of glasswool EO is classified by the U.S. Department of fiberglass insulation compressed to 3-1/2 inches by Transportation (DOT) as a primary poison gas an outer metal jacket. The ceramic fiber section also hazard (Division 2.3) with a subsidiary hazard provides additional protection to prevent an external of a flammable gas (Division 2.1), and must be fire from raising the temperature of the tank metal placarded accordingly. Further, it carries the to a point at which it loses strength. The outer metal materials poisonous by inhalation (PIH) designation jacket is 11 gauge (about 1/8 -inch) carbon steel, by the DOT. See also Chapter 11, Selected except at the ends of the car where tank puncture Regulations. resistance is provided by 1/2 -inch headshields. Such insulation systems have been used for EO railcars for a number of years and are credited as a major factor in the record of transportation safety achieved by this product.

Figure 9.19.1 DOTDOT 105-J105-J railcar for transporting Ethylene OxidOxidee

4” Glass Wool Insulation Compressed to 31/2” and Gauging Device, Safety Valve, 3/4” Thermometer Well 0.65” (Ceramic Fiber) Thermal Protection 3 - 2” Angle Valves & /4” Sample Line Angle Value

1/2” Jacket Head

9/16” Tank 116" Head Inside Dia. Center Line 9/16” Tank 13’ - 11/4” of Angle Valve Top of Grating 13’ - 11” A–End B–End

2’ - 101/2”

40’ - 11” Truck Centers 51’ - 10” Over Strikers 54’ - 51/2” Coupled Length

The dynamics of an EO railcar engulfed in flames 15’- 415/16" are complex. For a more detailed discussion, consult Chapter 10.

Design – Pressure Relief DOT requires that railcars in EO service must be provided with one or more pressure relief devices. The regulations also require that pressure relief devices must be of a type that will resist dynamic forces including liquid surge. The pressure relief device is to be set to open at a pressure of 75 psig (5.2 barg). It should be noted that the pressure B-End relief device may begin to weep at approximately 10’ - 5” 10 percent below pressure. Once the pressure Over Grabs relief device opens, it does not reseat bubble tight until 60 psig.

Design – Excess Flow Check Valves of liquid or vapor prior to its design shut off flow EO tanks are equipped with float type excess flow of 120 gpm. If the excess flow check valve closes, check valves underneath each liquid load/unload the pressure needs to be equalized to force the valve and vapor valve. This is a safety precaution internal plug back to the open position. Equalizing as the valve is designed to shut off the flow of the pressure can be performed by closing the liquid or vapor if the valves are “sheared” from the load/unload valve on the liquid line. In extremely cars pressure plate during an accident. An excess unusual circumstances, the vapor valve can get flow valve is not designed to, and will not, shut off stuck closed if there is EO polymer present in flow in the event of minor or slow leaks from valves, the vent line. Nitrogen pressure may have to be hoses, or flanges. supplied on the downstream side to force the internal plug in the valve back to the open position. If a liquid or vapor valve is opened too rapidly or if an excessive unloading rate occurs, the excess Be aware that the vapor line excess flow check flow check valve may close, cutting off the flow valve can close if the car is depressurized too

Figure 9.2 Dome Arrangement of a maintained under an atmosphere of an oxygen- DOT 105-J Railcar for free, inert gas. Air (oxygen) is not allowed to enter Ethylene Oxide Service railcars or other transportation containers when in EO service, whether filled or unloaded. A vapor environment with an oxygen level of less than 1% has been generally considered “oxygen-free.” Dry nitrogen has been successfully and widely utilized as an inerting gas for railcars and other transportation containers. It has limited solubility in liquid EO.

CAUTION: Carbon dioxide is generally not considered suitable as an inerting gas for railcars and other transportation containers. CO2 exhibits very high solubility in liquid EO (approximately rapidly. If the excess flow check valve closes, a ten times that of nitrogen), allowing the cargo false reading of railcar pressure can occur, as (or heel) of EO to absorb a significant quantity pressure is measured in the line downstream of the of carbon dioxide from the railcar vapor car loading/unloading valve. space. This inherent property of CO2 to readily dissolve into EO can result in a sizeable If the excess flow check valve has inadvertently depression of both the CO2 partial pressure closed, the railcar could be mistakenly over- and total pressure within the void space of pressured and lift the pressure relief device set at a railcar. As a consequence, the pressure 75 psig. Again, by closing the load/unload valve, the within the railcar could fall precipitously to a pressure can equalize on both sides of the excess sufficiently low level to be rendered non-inert, flow check valve and gravity should drop the float and susceptible to hazardous decomposition back into position. reactions. Significant problems experienced with loading Other general considerations include: and unloading operations such as malfunctioning equipment, running gear, or loading appliances • EO is highly reactive. should be reported to the EO supplier. Other than • The use of dedicated EO unloading facilities emergencies, repairs should only be performed is extremely important to help avoid with supplier approval in order to maintain contamination of EO with other chemicals. material quality, equipment function, and design • The unloading area should be well ventilated requirements. Emergency repairs should be and away from sources of ignition. reported to the supplier before putting the car in transportation. • OSHA requires that exposures not exceed either 1 ppm averaged for an 8-hour period or 5 ppm Preparation for Unloading over a 15 minute period (excursion level). Persons unloading a railcar or offering an unloaded • Use appropriate respiratory protection (see railcar for transportation have had general training Section 7.5) when making/breaking connections, with respect to general safety awareness and and during EO product sampling. railcar operation; function-specific requirements; • Know where safety showers and eye wash and safety/emergency response. 49 CFR 172.704 facilities are located in the railcar unloading requires refresher training at intervals (at least area. every 3 years). • Know the location, in the unloading area, of fire Remember that EO in a railcar is constantly fighting equipment (extinguishers, fire monitors, hose reels, deluge systems) and know how to use these.

• Consider checking or replacing any fire Figure 9.3 DOT “Stop—Tank Car extinguishers with broken seals before Connected” Sign commencing unloading. It can be useful to develop and provide to unloading personnel a detailed site-specific procedure and checklist specifying each step of the unloading operation and the precautions to be observed. Consider maintaining an operator unloading log to record key information for both the railcar and the receiving storage tank or vessel, such as: • Railcar and storage vessel temperature • Railcar and storage vessel pressure • Storage vessel level • Railcar numbers • Seal numbers Consider recording and monitoring the temperature of EO railcars from time of arrival onsite up through railcar unloading. The presence of higher than normal temperature or a temperature rise not explained by ambient conditions may indicate the presence of contamination and the potential for reaction in the railcar. Consider maintaining records of all previous cars received at that site to understand the normal temperature of EO. See Chapter 5 for a discussion of the hazards of contamination and Chapter 10 for emergency response. DOT requires that the DOT car specification number on the car must be 105-J300W. “Ethylene Oxide” and “Inhalation Hazard” must be stenciled on opposing sides of the railcar. Check the dome for an intact seal. If the seal is not intact, check for signs of tampering and monitor railcar temperature and verify as stable before unloading. Notify the EO supplier if the seal is not intact. If the temperature is not stable or contamination is suspected, initiate emergency procedures as described in Chapter 10 of this manual. Typical steps for unloading EO follow, along with a series of photographic illustrations. The DOT requires placement of blue signs that read “Stop — Tank Car Connected” or “Stop — • Locking track switches and utilizing a derail Men at Work” at appropriate spots. mechanism to prevent collisions with other cars.

Typical steps for unloading (photographic illustrations);

1 2

• Setting the hand brake (DOT requirement). • Chocking the car front and back of at least one wheel (DOT requirement).

3 4

• Grounding the railcar on its bolster or on the • Raising the dome cover. Note how the top working area. Because corrosion between personnel are inspecting the area under the bolted and riveted parts on railcars can serve dome carefully - use caution, as valves and as insulators between the ground clamp and devices under the dome could leak. the tank, continuous continuity checks are helpful when grounding the railcar as shown in the photo above. Regardless of where the grounding clamp is applied, maintain metal- to-metal contact between the clamp and the selected railcar hardware.

• Measuring and recording the temperature of the EO in the railcar by lowering a thermocouple or thermometer into the thermowell (allow several minutes for the temperature measurement to stabilize).

Figure 9.4 Canister Mask with Ethylene Figure 9.5 Positive Pressure “Hoseline” Oxide-Specific Canister Type Respirator

Experience has shown that it is difficult to meet the 1 ppm exposure limit when connecting or disconnecting EO railcars. If the 1ppm exposure limit is not met, OSHA-compliant respiratory protection is available for operator use when making or breaking connections on EO railcars. Supplied air breathing devices exist for both normal operations/maintenance activities and emergencies. Check with manufacturer for details..

Unloading • Check the valves, flanges and relief device in the dome for leaks. Leak detection procedures Typical steps for the transfer/unloading of the EO that are commonly practiced include use of a from the railcar to the receiving storage vessel soap solution and detection with monitoring are noted here. The sequence of procedures or devices (flammable gas detectors or EO- procedures used may vary by company; the steps specific detectors). A leak could result in provided here are for illustration purposes only. several hazards: • Wear proper PPE. Experience has shown — Reduction of the pressure within a railcar that it is difficult to meet the 1 ppm exposure resulting in a vapor space that is not inert. limit when connecting or disconnecting EO Additional nitrogen injection into the railcar railcars. If the 1ppm exposure limit is not will restore the inert atmosphere. met, operators should wear OSHA compliant respiratory protection when making or — Presence of flammable vapors around the breaking connections on EO railcars. Supplied railcar. air breathing devices are suitable for both — Potential for exposure above OSHA levels. normal operation/maintenance activities and (Note: in addition to flammable vapor around the emergencies. Canister masks are generally leak, railcar leaks could result in a railcar vapor protective for limited concentration levels. space that is not inert, requiring additional Check with manufacturer for details. nitrogen injection into the railcar to restore the inert atmosphere.)

Typical steps for the transfer/unloading of the EO from the railcar to the receiving storage vessel.

1 • Insert pipe extensions into the valves so that • Remove plugs in both vapor and liquid valves. connections can be made outside the dome of the car. Be sure that pipe extensions do not interfere with operation at the valve operating mechanism.

3 4

• Attach the unloading line to the liquid valve • Purge lines with nitrogen to remove any air that extension. might be present. • Off-loading can be accomplished by either • Install a pressure gauge on the vapor line. pressuring or pumping EO from the railcar. Measure and record pressure. Refer to Figure In either case, (a) nitrogen and/or (b) vapors 6.16 in Chapter 6 (Design of Facilities) for displaced from the tank receiving the EO are guidance on selecting proper nitrogen pressure needed to replace the liquid and to maintain to maintain a non-explosive EO vapor content railcar pressure. while unloading EO. • Check for leaks on hose connections prior to • Monitor temperature and pressure throughout introducing EO. the unloading process. • Either (a) attach nitrogen, or (b) line up the vapor balance return line to the railcar vapor line to provide for maintenance of the railcar nitrogen pad.

• Maintain the railcar pressure in non-explosive region during unloading by adding either (a) nitrogen or (b) displaced vapors from the receiving vessel via the railcar vapor line as the inventory of EO in the railcar is depleted. Minimizing the heel remaining in an EO railcar after unloading is a very important consideration when developing unloading procedures. Unloading procedures that utilize vapor balancing typically employ pumps to transfer EO from the railcar to the storage vessel. Such facilities and procedures should be designed to prevent a premature stop in the unloading process, possibly resulting in a large heel of EO remaining in the railcar. Unloading practices might include blowing vapor through the railcar and losing liquid flow from a pump as a method of minimizing remaining • Carefully open the vent and liquid valves. If liquid heel. However, operating a pump without flow utilizing a pump to unload the EO, check the for any duration of time could result in an EO vapor unloading pump to prevent deadheaded or decomposition. Refer to Section 6.7 on piping and vapor-bound operation. pumps for more information. Detecting the loss of liquid flow can be achieved by such means as a flow switch or ultrasonic device in the liquid line. In some cases, the use of a properly designed sight glass (e.g. “bullseye”) may be appropriate. The excess flow check device consists of a float that becomes buoyant at high flow. Once closed, the excess flow check valve will not reopen until the pressure differential on both sides of the valve is equalized. Remember that the railcar pressure monitor is downstream of the vapor check valve and therefore will not read car pressure if the excess flow check valve is closed.

Inerting the Unloaded Railcar for Return Unloading a tank or a shipping container of liquid EO does not remove the danger of vapor • If sampling is part of the procedure, sample and decomposition because unloaded railcars contain obtain laboratory verification before unloading a residual heel of EO liquid. The heel results in the the railcar. Grounding of the sample cylinder is continued presence of EO vapor. As long as EO recommended to prevent static sparks. vapor remains in a vessel, the railcar needs to be pressurized to maintain an inert atmosphere using NOTE: Polymer has a tendency to build up in either pure nitrogen, or in the alternative, vapors the railcar sampling line in cars equipped with displaced from the EO storage tank into which a sampling valve. Sampling from the offloading the railcar is discharged. Railcar pressurization line reduces potential for plugging. is a DOT requirement found at 49 CFR, Chapter 1, Part 173.323 (f).

After the cargo of EO is unloaded, the transfer Table 9.1 Illustration – Pressuring lines to EO storage are blown with nitrogen. Once Unloaded Railcars with Pure nitrogen flow is evident in the receiving tank or Nitrogen (Assuming 50 Gallon vessel, the liquid unloading line is closed and Ethylene Oxide Liquid Heel) secured. Pure Nitrogen Makeup The composition of the vapor space within a railcar can be significantly affected by temperature 50 GALLON EO LIQUID HEEL and vaporization of the remaining heel. As a Railcar Temperature Railcar Pressure – consequence, railcar inerting requirements differ Range –°F PSIG significantly from those defined for storage tanks and are dependent on the source of the inerting From To Minimum1 Maximum2 gas. 25 30 20 50 EO railcars are designed to leave minimal volumes 31 35 20 50 of residual liquid (typically less than 50 gallons) after the cargo is discharged. Tables 9.1 and 9.2 36 40 20 51 illustrate railcar pressurization for a 50 gallon heel. 41 45 20 52 The data in Tables 9.1 and 9.2 are valid for a 50 gallon heel. Higher minimum pressures are 46 50 20 53 used for larger heels to achieve proper inerting 51 55 20 53 and lower maximum pressures are used to prevent lifting of the relief valve. 56 60 20 54

In Tables 9.1 and 9,2, it is assumed that the inert 61 65 20 55 atmosphere will be maintained up to a temperature 66 70 20 55 of 105°F (as required by DOT) while maintaining the railcar pressure below the 75 psig setpoint of the 71 75 20 56 pressure safety valve. This illustration addresses 76 80 20 57 pressurization with either pure nitrogen or tank vapors from an EO storage tank inerted with 81 85 20 58 nitrogen. 1 Minimum is set to meet DOT requirement for a non flammable This illustration addresses potential vaporization of vapor space at 105°F. EO into the vapor space that might occur during 2 Maximum is designed to reduce likelihood of potential the time interval required for unloading, pressuring, release from relief valve in transit should the railcar reach or and securing the railcar. (See Appendix C for exceed a temperature of 105°F. additional information.) Pressuring unloaded EO railcars by vapor balancing (EO receiving tank vapors) for return to the supplier is slightly more complex, because the level of pressurization is dependent on the starting temperature of the EO tank from which the vapors are directed to the railcar. Supplementary pure nitrogen may need to be added to the railcar if the balance tank vapors cannot provide the necessary pressure level required to achieve an inert vapor space as dictated by DOT regulations.

Table 9.2 Illustration – Repressuring other hazardous, liquified compressed gases (other Unloaded Railcars – Vapor regulatory sections may also apply): Balancing (50 Gallon Ethylene • 172.101-102; Oxide Liquid Heel) • 173.32; VAPOR BALANCING • 173.323; LESS THAN 50 GALLON EO LIQUID HEEL • 178.245 -1 through 7; and

Balance Tank Temp. Railcar Pressure – • 178.272-276 Range –°F PSIG

From To Minimum1 Maximum2 9.6 Non-Bulk Packaging for High

25 30 20 50 Purity Ethylene Oxide EO can be shipped in small quantities in cylinders 31 35 20 50 and drums. It is a violation of federal law to use a 36 40 20 50 cylinder or drum of EO in a manner inconsistent with its labeling. Only qualified EO handling 41 45 20 50 facilities, with appropriate safeguards and properly 46 50 21 52 trained personnel, following applicable local, state, and federal laws, should fill non-bulk EO 51 55 24 53 containers. 56 60 28 53 The most common use of EO in non-bulk packaging is for the sterilization of medical devices 61 65 31 53 and reduction of microbial load in spices. These 66 70 35 53 activities must comply with EPA’s regulation of pesticides under the Federal Insecticide Fungicide 71 75 39 53 and Rodenticide Act (FIFRA) at 40 CFR Subchapter 76 80 43 53 E and FDA’s Quality Systems Regulation (21 CFR 820). 81 85 46 55 The following discussion addresses EO in 1 Minimum is set to meet DOT requirement for a non flammable DOT specification cylinders and UN 1A1 Drums. vapor space at 105°F. Transportation-specific comments apply to 2 Maximum is designed to reduce likelihood of potential shipments that fall under the DOT hazardous release from relief valve in transit should the railcar reach or materials table (49 CFR 172.101) description exceed a temperature of 105°F. “Ethylene Oxide with Nitrogen.” This section applies only when EO is the primary component in the 9.5 IM Portable Tanks container, apart from the nitrogen inerting gas, (Intermodal/Iso-Containers) and that the contained EO is in the liquid phase. Although movement of EO in IM Portable Tanks Specific regulations cited here may not apply to (Intermodal/Iso Containers) is practiced in various users of EO in other non-bulk packaging. regions of the world and also is approved as Design – General a mode of transportation in North America, IM Portable Tanks are not typically utilized for EO EO in non-bulk packaging must meet the service in North America. requirements of 49 CFR 173.323 (b). Cylinders must meet DOT Specification Cylinder Requirements More information concerning rules and regulations of 49 CFR 173.40 and UN 1A1 Drums must comply for IM Portable Tanks in EO service are found with 49 CFR 178.504. Commonly used non-bulk in the Code of Federal Regulations Title 49— containers are: Transportation. EO is considered a hazardous, liqueified compressed gas by the U.S. DOT. The • 400 Pound 1A1 Drum following sections of CFR Title 49 specifically • 175 Pound 4BW240 Cylinder address the use of IM Portable tanks for EO and • 20 Pound 4BW240 Cylinder

at Title 49 of the Code of Federal Regulations, Part Figure 9.6 Commonly Used Non-bulk Containers 178.600 et seq. Federal regulations require UN 1A1 drums to be of all welded construction with a non-removable head. “The inner, pressure-containing shell must have a minimum thickness of 0.068 inches (1.7-mm), and the outer shell a minimum thickness of 0.095 inches (2.4 mm). Drums must be capable of withstanding a hydrostatic test pressure of 100 psig (690 kPa). Openings for filling, unloading and venting in the bodies or heads of non- removable head (1A1) drums may not exceed 3 inches (7.0 cm) in diameter. Closures for openings in the bodies and heads of drums must be designed and applied so that they will remain secure and leakproof under normal conditions of transport. Regulations also require cylinders over 1 gallon (4 liters) capacity to have pressurizing valves and insulation. Eductor tubes must be provided for cylinders over 5 gallons (19 liters) capacity. Cylinders must be seamless or welded steel All non-bulk packaging of EO must be labeled in (not brazed) with a nominal¡ capacity of no more accordance with federal regulatory requirements. than 30 gallons (115 liters). Each cylinder must be DOT hazard labels for both the primary (2.3) and equipped with a fusible-type relief device with yield subsidiary (2.1) hazards must be properly affixed temperature of 157°F to 170°F (69°C to 77°C). The to the containers and any outer packaging. OSHA capacity of the relief device and the effectiveness Hazard Communication requirements (29 CFR of the insulation must be sufficient to prevent a 1910.1200) and applicable EPA FIFRA (40 CFR 156) charged cylinder from exploding when tested by labeling requirements must be met. Note that the method described in CGA Pamphlet C-14 or OSHA also has an ethylene oxide-specific standard other equivalent method. that should be consulted (29 CFR 1910.1047). There are two valves commonly used in drum Non-bulk containers must be equipped with and cylinder service: a nitrogen valve and a liquid insulation of sufficient thermal resistance and valve with an attached dip tube. A nitrogen valve provided with adequate pressure relief devices to (CGA 580) is used to pressurize the container with prevent rupture when exposed to fire. Cylinders nitrogen. This valve has a spring activated relief and drums are equipped with fusible relief devices which is set at 75psig by CGA requirements, and with yield temperatures of 157°F to 170°F (69°C to can only operate when the valve is open. This 77°C). Cylinders and drums have a pressure relief valve provides relief to protect the package from device that relieves at 75 psig. Refer to 49 CFR over-pressurization while in use only. If the relief 173.323 and CGA Pamphlets S-1.1 and C-14. is activated, it will reset once pressure is reduced EO in containers or cylinders is padded with dry below 75 psig. This valve has a CGA 580 right-hand nitrogen at sufficient pressure to render the vapor internal thread connection with a silver handle. space non-flammable (e.g., up to 41°C (105°F)). A liquid valve (CGA 510) is used to unload the Nitrogen is typically padded to a pressure of contents of the container. There is a dip tube 50 psig. threaded into the valve that extends to the bottom EO may be shipped in UN 1A1 insulated steel drums of the container which is used for liquid unloading. of no more than 61 gallons (231 liters) capacity. This valve has a CGA 510 left-handed internal Packing Group I performance standards are set out thread connection with a red handle.

Figure 9.7 Typical Drum Connections

Preparation for Unloading Containers (Position Statement on the Safe Transportation of from Transport Vehicles Cylinders in Vehicles). Federal regulations require all persons offering There are several National Fire Protection EO for transportation to be trained with respect to Association (NFPA) standards that may general awareness and familiarization; function- be applicable to a particular use: NFPA 55 specific requirements; safety - emergency (Compressed & Liquefied Gases in Cylinders) and response; and hazardous material security. 49 CFR NFPA 560 (Standard for Handling, Storage, Use of 172.704. Refresher training must be conducted at EO for Sterilization/Fumigation). Other standards intervals not exceeding 3 years. See also Chapter may be applicable. 11, Selected Regulations. Advance arrangements for transportation of drums Users of drums and cylinders may also wish and cylinders are generally made by the supplier of to consult CGA Pamphlets P-1 (Safe Handling the EO. If the end user chooses to return emptied of Compressed Gases in Containers) and PS-7 containers, transporters/carriers should have any

necessary regulatory approvals for transporting forklifts). Also note that some cylinders and drums or handling hazardous materials, and should be are equipped with caps to help protect valves sufficiently familiar with the properties and hazards from damage; having these caps in place during of EO to transport the materials safely. The DOT all times except when needed to access the valve requires all carriers and end users of EO to be helps protect the cylinders and drums. registered as handlers of hazardous material and Full and unloaded drums are also stored with care. to comply with the DOT security rule. Note that They are generally designed to be stored upright, suppliers often request or require that they be in a well-ventilated area. Damage to an eductor contacted before unloaded EO non-bulk containers tube can occur to a cylinder stored on its side. It are returned to them. is desirable to store the drums in a manner that avoids heat build up, so consider controlling the Unloading Drums and Cylinders temperature of the storage area and sheltering from Transport Vehicles the drums to avoid direct sunlight or other sources After the vehicle carrying drums or cylinders of heat. Give consideration to the location of the arrives at its delivery destination, the engine is pressure relief devices (ability to vent without generally shut off (unless needed to remain on for obstruction or other safety considerations) while a particular purpose, such as to operate a lift gate) the drums are stored. Store drums in a manner to minimize risk of ignition. Chocking the wheels to provide adequate protection from physical and using the handbrake of the truck or other damage, and provide an adequate schedule of motorized vehicle will help prevent the truck from checking for cracks, leaks, faulty valves, or other moving and keep it stable during the unloading circumstances to be addressed. process. All areas for unloading or storage of EO are Unloading (Discharging) Drum considered Class 1, Division 2, and Group B as and Cylinder Contents defined by the National Electrical Code. The The information provided in this section is intended NEC prohibits open flames, smoking, or other to introduce information and general principles combustion sources in the vicinity of the vehicle of safe handling with regard to the receipt, use being unloaded. Give consideration to providing and return of cylinders and drums containing EO. adequate ventilation in the unloading area during The end user should request detailed instructions the unloading process, and in trucks or other from the EO supplier concerning specific types of motorized vehicles before and during the unloading cylinders or drums. process. Considerations while unloading drums and Use caution when entering a trailer or other cylinders include: transport vehicle that may contain the drums • Cylinder or drum fittings are inspected for or cylinders of EO; in this regard, the use of wear or possible damage. (Where damaged area or portable EO-specific detection devices cylinders/drums are identified, contact the can be a very useful tool. During the unloading supplier for further instructions). process, check the containers for damage and • leaks. If a leak is suspected or any containers are The threaded connections and valve are damaged, initiate appropriate emergency response inspected for dirt, grease, or obstructions. procedures and contact the supplier. Note that some threaded connections may be designed to work without lubricants, and Unloading drums and cylinders must be performed the use of lubricants on such threadings may with care. Puncturing or damaging the drums is to impede performance. be avoided, as is exposing them to heat or fumes. • Select unloading equipment that will avoid or Use of a check valve or other backflow minimize damage to drums and cylinders. Using prevention device in the discharge line will help a handtruck or pallet jack, as appropriate, will prevent backflow and entry of contaminants into help avoid rough handling of the drums (rolling, the EO cylinder or drum. dragging, or sliding them), which can damage • Use of spark-resistant tools can help minimize them, and also helps avoid the risk of damage from the risk of sparking. the use of powered equipment (such as motorized

At all times during unloading, the container is 9.7 Ethylene Oxide Shipping Data properly secured. This helps avoid unintentional movement or fall of the container. When selecting a Table 9.3 Temperature/Density/Vapor storage area, consider locations that will minimize Pressure for Shipping Ethylene inadvertent contact that could lead to a puncture; Oxide for example, storage areas well away from traffic lanes. Note that drums and cylinders may be Temperature Density Vapor Pressure designed for valve protection, such as cylinder (lb/gal) (psia) caps valve plugs, to be kept in place and secured 20°F 7.59 7.1 at all times when the container is not being loaded or unloaded. 40°F 7.47 11.6

Nitrogen is used to maintain cylinder and drum 60°F 7.34 18.0 pressure and to discharge the EO from the container. (The valve located at the discharge 80°F 7.21 26.9 connection of the drum or cylinder is useful for 100°F 7.08 39.1 throttling and regulating the flow of EO from the container and also for providing the required 105°F 7.05 42.7 backpressure to maintain the container vapor space within the non-flammable inert region.) According to DOT federal regulations (49 CFR 173.24b), EO The nitrogen is at a high enough pressure to railcars and portable tanks must be loaded to ensure that a maintain the container vapor space within the 5% outage exists at a temperature of 105° F. non-flammable or inert region. Follow the supplier’s instructions regarding appropriate pressure to 9.8 Shipments of Ethylene Oxide achieve inerting. With the drum and cylinder between the U.S. and Canada designs discussed in this manual, a pressure Canada has established regulations for the of about 50 psig has been used in practice for Transportation of Dangerous Goods (TDG) within pressuring and unloading a cylinder or drum. Note Canada. Canada identifies EO as a dangerous that the use of a backpressure control valve or good subject to TDG rules. This section provides regulator can help prevent overpressuring the EO a brief overview of Canadian requirements; the drum or cylinder. user should consult the regulations for more information. Securing the Unloaded Drum or Cylinder for Return to Supplier Canadian TDG regulations require that the importer of record for EO into Canada must have an An emptied drum or cylinder may contain residual approved emergency response assistance plan quantities of EO, which can pose a danger of vapor (ERAP) on file with Transport Canada. Part 7 of the decomposition. Due to possible residual EO, these TDG Regulations outlines this requirement and containers are handled very carefully. Column 7 of the dangerous goods list provides the DOT regulations require that any unloaded cylinder ERAP Index. or drum containing the residue of a hazardous material be transported in the same manner as Shipments of EO from within the U.S. when it previously contained a greater quantity of to, or through Canada that hazardous material. DOT requires containers TDG Regulations allow shipments of EO that to be returned to the supplier as a hazardous originate from within the United States to be material. Packages must retain DOT Hazard transported into or through Canada under the markings 2.3 and 2.1 (Poison Gas placard and classification, marking, labeling, placarding and Flammable Gas placard). DOT regulations require documentation requirements of Title 49 of the US the shipper to ensure that any truck carrying EO is Code of Federal Regulations (49 CFR). appropriately placarded.

More details concerning Transportation of may be transported to or through the United States Dangerous Goods from the United States into or by railcar or tankwagon / road vehicle, provided through Canada can be found in the Canadian that: Government’s Transport of Dangerous Goods • Shipping papers contain the words “Toxic Regulations, Sections 9.1 and 10.1, and other Inhalation Hazard” or “Poison Inhalation Hazard” referenced sections, for the shipment of EO by or “Inhalation Hazard”; and either road or rail, respectively. • A label or placard that conforms to the Shipments of EO from within Canada specifications in the TDG Regulations for a to, or through the U.S. “Class 2.3” label or placard may be substituted for the POISON GAS or POISON INHALATION The U.S. DOT has established provisions for HAZARD label or placard, and EO shipments originating within Canada that terminate within the United States, or which travel • The containers used for shipping EO as through the United States to a Canadian or foreign authorized by the TDG Regulations correspond destination. These regulations also apply to the to the USDOT specification or UN packaging return to Canada of any unloaded bulk packages specifications for EO. containing residues of hazardous materials that Details concerning the shipment of hazardous were originally imported into the United States. materials originating from within Canada can be Shipments of EO originating within Canada that are found in the U.S. Code of Federal Regulations, properly marked, labeled, placarded, described Title 49, Part 171.12a, Canadian Shipments and on a shipping paper, and packaged in accordance Packaging. with the Transportation of Dangerous Goods (TDG) Regulations issued by the Government of Canada

10.0 Emergency Response

10.1 Introduction • Can cause blistering and severe chemical burns Every emergency situation will be different. It is not — Easily penetrate cloth, leather and some the intent of this manual to address every potential types of rubber. Leather cannot be situation; it is intended to help producers, users, decontaminated. and others as a resource in the development of • EO vapor can be absorbed by wet or sweaty their own emergency procedures for EO. skin with potential for serious chemical burns. Emergency responders must be properly • Odor thresholds are much greater than trained and equipped in accordance with OSHA permissible exposure limits; overexposure standards on emergency response and emergency occurs before the odor can be detected. fire protection (29 CFR 1910.38, 1910.120 and • Inhalation of EO vapors: Subpart L). The first priority in responding to an emergency situation is the safety of the emergency — Can irritate exposed surfaces (eyes, nose, responders, employees, and people in the throat and lungs). surrounding community. The second priority is to — Potential effects on central nervous system determine the incident’s impact on the surrounding include drowsiness, nausea, convulsions environment, and to set a strategy to stabilize the and limb weakness. situation and minimize the impact. The third priority • IARC (International Agency for Research on is the conservation or protection of equipment and Cancer) classifies EO as Class 1 — carcinogenic property. to humans[2]. Downwind evacuation should be considered if • Water contaminated with EO evolves EO vapor EO is leaking but not on fire. For large spills, DOT and can be a source of exposure. recommends “first isolate in all directions at least 200 feet.” DOT further recommends protecting Fire Hazards persons downwind during the day at least 0.3 miles and during the night at least 1.1 miles. In case of See also Chapter 2, Properties of Ethylene Oxide. small spills, DOT recommends first isolating for • Volatile flammable liquid with heavier than air 100 feet and protecting downwind persons for at vapors that may travel considerable distance to least 0.1 miles. a source of ignition. If a tank or rail car is involved in a fire, isolate • Lower Flammable Limit: 2.6% in air. Upper and consider initial evacuation for one mile in all Flammable Limit: 100% in air. directions. If the fire is prolonged or uncontrollable, • Fire impingement on EO-containing equipment or if a container is exposed to direct flame, can result in explosive decomposition, which consider evacuation for one mile in all directions can rupture the vessel and result in an EO vapor for protection from flying debris if the container cloud explosion. should rupture violently. [1] • Water/EO mixtures can support combustion if water/EO ratio is less than 22:1 (vol/vol) in open 10.2 Potential Hazards areas. For more information on potential hazards • In closed systems such as sewers, water/EO attendant to EO emergency response and selection mixtures with a ratio of less than 100:1 (vol/vol) of PPE, see also Chapter 3, Health Effects of can potentially flash. Ethylene Oxide, and Chapter 7, Personnel Exposure. • May polymerize violently in container if exposed Health Hazards to heat. • Liquid EO and EO/water solutions: • Often a secondary vapor cloud explosion resulting from a primary event could cause — Are extremely irritating to skin and eyes more damage than the primary event itself.

Hazards of Contamination Extinguishing Techniques • Reacts with water, evolving heat. In closed • Stay upwind. containers, reaction may be self accelerating, • Avoid physical contact with product. resulting in container rupture. • Wear self-contained breathing apparatus • Contamination with acidic or basic materials (SCBA) and appropriate protective clothing. accelerates reactions with water. Wear full chemical protective suit if contact with • Contamination of pure EO with acidic, or basic material is anticipated. materials; metal oxides, metal chlorides, or • For a large fire or a fire where there is flame active catalyst surfaces may cause explosive impingement on EO containing equipment, use polymerization. unmanned hose holders or monitor nozzles. Focus on minimizing the transfer of heat from 10.3 Fire Response the fire to piping and equipment containing EO to minimize the possibility of decomposition Special considerations for EO-containing reactions. equipment exposed to flames or with flame impingement: • Where the fire is not impinging or heating EO- containing equipment, consider letting the EO • In almost all cases, EO decomposition will result burn (controlled burn) as in a hydrocarbon fire. in overpressure and equipment failure Focus on minimizing the potentials for a vapor • EO decomposition initiation temperature cloud explosion. decreases as pressure increases • Withdraw immediately in case of prolonged • Polymerization can occur with flame venting of safety device or discoloration of impingement leading to loss of containment. equipment. Depending on the scenario, the reaction can • Keep fire-exposed containers and nearby go very quickly or take many hours to build to a equipment cooled using water spray. Minimum point to lose containment. 500 gpm/point of flame impingement. • Maintain water on any equipment exposed to • The addition of warm water (above 51°F/11°C) flames particularly uninsulated parts to pools of liquid EO may temporarily increase • Relief valves are not designed for vapor evolution. decomposition or polymerization If there is potential for runaway internal reaction, • Keep personnel at an appropriate distance or flame impingement that can result in explosive decomposition and container rupture, consider Extinguishing Materials evacuation for a one mile radius according to DOT • Carbon dioxide or dry chemical fire recommendations. extinguishers are suitable for small fires only. Considerations Whether to • Water fog or spray is more suitable for larger fires. In general, more water is beneficial Extinguish a Fire because it will cool the equipment, extinguish Flame impingement on EO-containing equipment the fire, dilute the EO release to the atmosphere can result in explosive decomposition. Because and reduce the potential for a vapor cloud. of this, a responder should strongly consider extinguishing a fire if there is a potential for flame • Water dilution for EO spills should be at least impingement on EO-containing equipment, even 22:1 (vol/vol) in open areas, and at least 100:1 if the source of the hydrocarbon feeding the fire (vol/vol) in closed areas where vapors might be has not been stopped. After the fire has been trapped (e.g., storm sewers). extinguished, continue to apply large volumes • Alcohol resistant foams (ATC type) are suitable of water on the leak to dilute the EO, which for fighting EO fires. General-purpose synthetic will minimize the potential for re-ignition of the foams (including AFFF) or protein foams may impinging fire or the potential for a vapor cloud function, but much less effectively because explosion. these foams are less stable.

• 10.4 Spill Response Alcohol resistant foams applied to the surface of liquid EO spills may slow the release of EO General Information vapors into the atmosphere. Alcohol-resistant foams (ATC-type) function well; general-purpose • Proceed with caution. synthetic foams (including AFFF) or protein • Restrict access to spill area. foams function less effectively because these • Keep unprotected personnel upwind of spill. foams are less stable in EO. • Monitor EO vapor concentrations in area. • Avoid contact with spilled product. 10.5 Emergency Response to Temperature Rise • Wear SCBA and a full chemical protective suit. A temperature rise in EO storage or an EO railcar • Eliminate ignition sources. (Minimum ignition may be due to a variety of factors, including: energy for EO/air mixtures is very low, • comparable to hydrogen and ethylene.) Loss of cooling in EO storage • • Prevent liquid EO and contaminated runoff water Off-loading railcar containing EO that is warmer from entering sewers and confined spaces than EO in storage (unless adequately diluted to 100:1 vol/vol) • Ambient conditions (typical rise in a railcar • Notify proper authorities as required by under summertime conditions is less than 2°F regulations. per day) • • If spill has the potential of entering a waterway, Reaction in storage vessel or railcar due to notify downstream users of potentially contamination contaminated water. A reaction in a storage vessel or railcar could result • Only equipment approved for use in flammable in catastrophic failure of the vessel. Pressure relief atmospheres should be employed in the vicinity valves on EO railcars and storage vessels are not of an EO spill. typically sized to protect against an uncontrolled reaction. • Be cognizant of the extremely volatile, flammable, and heavier than air nature of EO Figure 10.1 illustrates the temperature profile for a while planning the response. reaction of an EO/water mixture (neutral pH) with a high concentration of EO. The analysis assumes Air Release adiabatic conditions with no external cooling such as from cooling coils or autorefrigeration resulting Techniques for responding to releases to the from the lifting of a relief valve. The timeline is atmosphere include: not shown because it is highly dependent on EO • Evacuate and monitor local and downwind areas concentration, starting temperature, and other as conditions warrant to prevent exposure of types of contaminants. Some key observations personnel and to allow vapor to dissipate. from the graph: • Knock down vapor with water fog or spray. • Pressure increases and temperature increases Water fog or spray applied to EO vapors or can both indicate that a reaction is occurring. fumes will absorb a substantial amount of EO. • The temperature rise is slow initially and then • When using water spray, small quantities increases exponentially. may actually worsen conditions because of • It is important to record the temperature acceleration of vaporization. Large quantities of with enough frequency to track the rise in water are necessary to effectively knock down temperature. EO vapor and dilute spills. (See Section 10.7 for additional information.) • In a non-vented system, such as a railcar or a storage tank without pressure control, pressure rise is less effective than temperature rise in providing an early warning of a reaction.

• In a vented storage tank, pressure is even less 2°F / hour, time to respond could be shorter effective as an indicator of a reaction because than 1 hour before vessel failure could occur the pressure control valve will maintain constant due to overpressure. pressure in the vessel until the valve capacity • If contamination is suspected, proceed with an has been exceeded. emergency response plan for contamination • Refrigeration systems on EO storage vessels in vessel or railcar. See Section 10.6 for further can delay the detection of a reaction by discussion. maintaining temperature until the capacity of • If contamination of a railcar is suspected, notify the refrigeration system has been exceeded. the supplier immediately. Monitoring the heat load on a refrigeration system may be used for early detection of a CAUTION: DO NOT RETURN THE RAILCAR IF reaction. CONTAMINATION IS SUSPECTED WITHOUT FIRST DISCUSSING WITH THE SUPPLIER AS • The time from the point of contamination to the THERE MAY BE A RUNAWAY REACTION INSIDE point that the reaction is beyond control can THE RAILCAR. vary from hours to several days, depending on the type and concentration of contaminant and the initial temperature. 10.6 Emergency Response Plan • Sustained temperature rises can signal an to Temperature Rise uncontrolled reaction. See, e.g., Figure 10.1. Elements of an emergency response plan to As with any exothermic reaction, the greater address rising temperature of EO in storage or in a the temperature rise over time, the shorter railcar might include, as appropriate: the reaction time available to prepare for and • Increase frequency of measuring and recording respond to an incident. For example, if the the temperature of the EO in the vessel or temperature rise is approximately 1°F per hour, railcar. the time to respond could be less than a few hours; if the temperature rise is greater than

FigureFigure 10.110.1 Ethylene Oxide // WaterWater (Neutral)(Neutral) ReactionReaction TemperatureTemperature ProfileProfile EO / Water (Neutral) Reaction Temperature Profile (Graph for illustration only)

300 300 275 275 250 250 225 225 200 200 175 175 150 150 125 125 100 100 Temperature, ° F 75 75 Total Pressure, psi g 50 50 25 25 0 0 Time Temperature Total Pressure

• Slow temperature rise by removing heat such • EO and water are completely soluble in each as with a sprinkler system, cooling coils or other, and a water spray can be useful in water deluge. Sprinkler systems or deluge knocking down EO vapors. However, a water water have little effect on insulated vessels or spray directed on a pool of liquid EO will railcars (EO railcars are insulated). Be sure the increase evolution of EO vapors until significant cooling medium temperature is lower than the mixing and dilution of the liquid EO have temperature of the EO in storage. occurred. • Dispose of contaminated material as quickly as • Water/EO mixtures of less than 22:1 ratio can possible by feeding to downstream processors. support combustion in open areas. In closed This might include charging a water/caustic systems such as sewers, water/EO dilution or water/acid solution to a batch reactor, then ratios up to 100:1 are required to eliminate charging EO to convert the EO to glycols in the combustion potential. reactor. (The reaction rate for hydrolysis of EO From the above points it can be concluded that a to glycols may be much faster than the normal significant volume of water should be applied in process reaction.) Evaluate the design of the many EO emergency scenarios. In many cases, this reaction system for this scenario (heat removal, may be the maximum amount of water available. metallurgy, shut down systems, control systems, Having available at least 30,000 gallons of water pressure relief systems, etc). per hour to fight a fire allows for 500 gpm water • Transfer contaminated material to a designated flow per point of impingement for 60 minutes. This holding pond or tank with water. (The volume consideration is especially important in remote of water should provide at least a 22:1 vol/vol areas where water might not be readily available; in dilution ratio.) such cases, consider carefully whether to adopt an • Reduce reaction rate by venting to a properly evacuation strategy to an appropriate distance. designed EO flare or safe location (venting EO also reacts with water. At ambient conditions, results in auto-refrigeration of the contained the EO/water reaction occurs over days and EO). Discharge should be designed for months for dilute EO concentrations. The dispersion of EO vapors to avoid vapor cloud responder should not hesitate to apply water in explosion and to minimize personnel exposure. situations where EO has been released to the • Plan for evacuation of the unit, the plant, and environment, since the hazard of fire and personnel the surrounding community. exposure is far more significant than the hazard of an EO/water reaction. In a closed container, the heat release from the 10.7 Use of Water in Emergencies EO/water reaction can increase the temperature, Be aware of the following when considering the use leading to an accelerating or “runaway” reaction of water in an EO emergency response scenario: and loss of containment. This potential exists • Water can be useful for extinguishing EO unless the EO in the container can be rapidly fires and cooling equipment subject to fire purged out or diluted to a few weight percent. See impingement. discussion above in Section 10.5.

11.0 Selected Regulations

11.1 Introduction Appendix A to Section 119 — List of highly hazardous chemicals, toxics and reactives. The This Chapter is provided solely as background appendix contains a listing of toxic and reactive information and is not intended to substitute highly hazardous chemicals that present a for up-to-date research should a specific legal potential for a catastrophic event at or above question arise. It also is not intended to be a the threshold quantity (TQ). EO is listed, and the statement of legal requirements when using or TQ is 5,000 pounds. handling EO. Please consult with qualified experts regarding compliance with all applicable laws and .178(c)(2)(i) — Prohibits use of power-operated regulations. Although this Chapter is believed to industrial trucks in atmospheres containing be accurate, no warranty, expressed or implied, is hazardous concentration of EO. made concerning the contents. .1000 — The following federal regulations are not Table Z-1 — Lists limits for air contaminants represented as inclusive of all U.S. federal and refers to 29 CFR Section 1910.1047 for regulations that apply to manufacturing and EO limits. handling EO. The list specifically does not include: .1047 — • Federal regulations promulgated after the (a) Specific regulation covering all exposure Chapter was updated; and scenarios to EO except those below the • State and local regulations. action level (still requires retention of objective data for exempted operations). 11.2 Regulations — Numerical (b) Establishes action level of 0.5 ppm, 8-hour with Subject Listed time-weighted average (TWA). (c) Establishes permissible exposure limits of 1 Internal Revenue — ppm, 8-hour TWA and 5 ppm excursion limit Internal Revenue Service (15-minute average). 26 CFR Part 52 — Environmental taxes. (d) Requires exposure monitoring, including .4682-3 — EO/CFC-12 is included on the list initial, periodic, and termination samples, of imported taxable products. The EO/CFC-12 and periodic sampling every 3 or 6 months, mixture is used in example 3 of this Section. depending on exposure levels. Also includes standards for accuracy of monitoring and Labor — Occupational Safety and employee notification of monitoring results. Health Administration (OSHA) (e) Requires establishment of regulated areas 29 CFR Part 1910 — Occupational safety and health where EO concentrations may exceed 8-hour standards. TWA or EO concentrations exceed or can .19(h) — Applies the standards in 29 CFR reasonably be expected to exceed the Section 1910.1047 to the exposure of every excursion limit. employee to EO in every employment and (f) Delineates methods of compliance place of employment covered by Sections with exposure requirements including 1910.12 (construction work), 1910.15 (shipyard engineering controls (preferred) and employment), and 1910.16 (longshoring and personal protective equipment (PPE). Where marine terminals), in lieu of any other EO the TWA or excursion limit is exceeded, exposure standard that would otherwise be requires employer to establish and applicable. implement compliance program. (g) Outlines approved respiratory protection and PPE.

(h) Requires written emergency response plan, 29 CFR Part 1926 — Safety and health regulations including employee alerting procedures, for for construction. each workplace where there is a possibility .55 — of an emergency. Appendix A — 1970 American Conference (i) Outlines mandated medical surveillance of Governmental Industrial Hygienists’ plan; required for all employees who are Threshold Limit Values of Airborne or may be exposed at or above the action Contaminants. EO is included on the list, level (0.5 ppm) for 30 days or more per year, which refers to 29 CFR 1926.1147 for EO limits. without regard to respiratory protection, and for any employees exposed during an .64 — emergency event. Exams must be done prior Appendix A — List of highly hazardous to assignment to the work area, annually, chemicals, toxics and reactives. The at termination or reassignment, after an appendix contains a listing of toxic and emergency exposure, and where symptoms reactive highly hazardous chemicals which of over-exposure exist or when the employee present a potential for a catastrophic event requests medical advice concerning the at or above the TQ. EO is listed and has a TQ effects of current or past exposure on of 5,000 pounds. reproductive capabilities. .1147 — Applies the standards in 29 CFR Section (j) EO hazards communication requirements 1910.1047 to the construction industry. include signs at demarcation zone, precautionary labels on containers, National Defense — developing MSDSs as required, and initial Department of the Army and annual employee training programs. 32 CFR Part 627 — The Biological Defense Safety (k) Recordkeeping requirements include Program, technical safety requirements. objective data to support exempted .31(d)(6) — The PPE requirements for gloves operations (retained as long as employer state that sterilization of nondisposable gloves relies on the data), exposure measurements either before use or before reuse is usually (30-year retention period) and medical done with EO or formaldehyde gas. Sterilized surveillance records (duration of gloves must be aerated in flowing sterile employment plus 30-year retention period). (filtered) air at 21°C or higher for a minimum of (l) Permits employee or designated 24 hours prior to use to prevent skin burns and representative to observe any monitoring of irritation from residual decontaminants. employee exposure. .33(e) — Provides requirements for using vapors (m) Lists effective dates. All requirements took and gases as a method of decontamination. effect by December 6, 1988. States that formaldehyde, EO, peracetic acid, betapropiolactone, methyl bromide, and (n) Appendices A, B, C, and D provide non- glutaraldehyde have all been used successfully mandatory samples of an EO MSDS, as space sterilants where they can be technical guidelines, medical surveillance employed in closed systems and with controlled guidelines, and sampling and analytical conditions of temperature and humidity. Of methods, respectively. these, methyl bromide, beta-propiolactone, and 29 CFR Part 1915 — Occupational safety and health glutaraldehyde are not recommended because standards for shipyard employment. of their toxic properties. Peracetic acid can .1000 — Refers to 29 CFR Section 1910.1047 for readily decompose with explosive violence EO limits. in a concentrated state and must be used only in a diluted state and with extreme care. .1047 — Applies the standards in 29 CFR Formaldehyde and EO are both regulated by Section 1910.1047 to shipyard employment. OSHA for their potential human carcinogenicity, but do have permissible exposure levels (unlike

beta-propiolactone, for example) and can be 33 CFR Part 160 — Ports and waterways safety — used safely under controlled conditions. general. (2) Provides specific requirements for EO. .109 — District Commander or Captain of EO sterilization will only be conducted in the Port may direct the handling, loading, a sterilizer designed for that purpose and unloading, storage, and movement (including designed to maintain potential exposure the emergency removal, control and disposition) levels below the current OSHA standard. of explosives or other dangerous articles EO is effective against all microorganisms, and substances on any structure on or in including spores, molds, pathogenic fungi, the navigable waters of the United States, or and highly resistant thermophilic bacteria. All any land structure or shore area immediately materials to be used in contact with human adjacent to those waters. Also allows District skin (for example, clothing, shoes, masks Commander or Captain of the Port to conduct and adhesive tape) must be aerated for at examinations to assure compliance with the least 24 hours after sterilization and prior safety equipment requirements for structures. to use. Concentrations of 500 to 1000 ppm Applies to DOT hazardous material, which are required for sterilization. Specific OSHA includes EO. requirements for the use of EO are found in 29 CFR Section 1910.1047. Protection of Environment — U.S. Environmental Protection Agency (EPA) Navigation and Navigable Waters — 40 CFR Part 52, Subpart O — Illinois. U.S. Coast Guard (USCG) .741 — 33 CFR Part 126 — Handling of dangerous cargo at waterfront facilities. Appendix A — List of chemicals defining synthetic organic chemical and polymer .3 — Defines dangerous cargo to include all manufacturing. Includes EO. hazardous materials listed in 49 CFR Parts 170 through 179, which includes EO. Topics 40 CFR Part 60 — Standards of performance for addressed by Part 126 include the designation new stationary sources. of waterfront facilities, permits required for Subpart VV — Standards of performance for handling dangerous cargo, supervision and equipment leaks of volatile organic compounds control of dangerous cargo, and conditions for (VOC) in the synthetic organic chemicals conducting welding and hotwork. manufacturing industry (SOCMI). 33 CFR Part 127 — Waterfront facilities handling .489 — Includes EO on list of chemicals that are liquefied natural gas (LNG) and liquefied hazardous produced, as intermediates or final products, by gas. process units covered under this subpart. The applicability date for process units producing .1209 — Requires each waterfront facility handling LNG to provide respiratory protection one or more of these chemicals is January 5, equipment for each employee in the marine 1981. transfer area for LNG during the transfer of EO. Subpart III — Standards of performance for The equipment must protect the wearer from VOC emissions from the SOCMI air oxidation EO’s vapor for at least 5 minutes. unit processes. 33 CFR Part 154 — Facilities transferring oil or .617 — EO is included on the list of chemicals hazardous material in bulk. affected by Subpart III. .105 — Defines hazardous material to include all Subpart NNN — Standards of performance hazardous materials listed in 49 CFR Parts 170 for VOC emissions from SOCMI distillation through 179, which includes EO. Requirements operations. for facilities including operations manual .667 — EO is included on the list of chemicals and procedures, equipment requirements, affected by Subpart NNN. facility operations, vapor control systems, and response plans for facilities. Subpart RRR — Standards of performance for VOC emissions from SOCMI reactor processes.

.707 — EO is included on the list of chemicals Table 34 — Fraction Measured (Fm) and affected by Subpart RRR. Fraction Emitted (Fe) for HAP Compounds in Wastewater Streams. EO is listed with a Fm 40 CFR Part 61 — National emissions standards for hazardous air pollutants (NESHAP). value of 1.00 and a Fe value of 0.50. — Compound Lists Used for .01 — Lists substances that, pursuant to Table 36 Section 112 of the Clean Air Act (CAA), have Compliance Demonstrations for Enhanced been designated as HAPs. EO is listed and Biological Treatment Processes. EO is included the Federal Register citation for the EO listing on List 2. decision is 50 Fed. Reg. 40286 (Oct. 2, 1985). Subpart O — EO emissions standards for sterilization facilities. 40 CFR Part 63 — NESHAPs for source categories. — All sterilization sources using one ton Subpart D — Regulations governing compliance .360 extensions for early reductions of HAPs. EO in sterilization or fumigation operations are subject to the emissions standards in Section .74(f), Table 1 — List of high-risk pollutants. EO 63.362, except as specified. Subpart O does is listed with a weighting factor of 10. not apply to EO sterilization operations at Subpart E — Approval of state programs and stationary sources such as hospitals, doctors’ delegation of federal authorities. offices, clinics, or other facilities whose primary purpose is to provide medical services to .99 — Lists the specific source categories humans or animals. that have been delegated to the air pollution control agencies in each state, including .361 — Defines sterilization facility as “any the following for EO: Alaska (EO sterilizers); stationary source where ethylene oxide is used Arizona (EO sterilization facilities); Idaho (EO in the sterilization or fumigation of materials.” sterilizers); Louisiana (EO sterilizers); Nevada .362 — Provides standards for EO commercial (EO sterilization facilities); New Mexico (EO sterilizers and fumigators for sterilization sterilizers); Oklahoma (EO sterilizers); Oregon chamber vent, aeration room vent, and chamber (EO sterilizers); and Washington (EO sterilizers). exhaust vent. Subpart F — National emission standards for .363 — List the compliance and performance organic HAPs from the SOCMI. provisions for owners and operators of sources Table 1 — Synthetic Organic Chemical subject to the EO emissions standard. Facilities Manufacturing Industry Chemicals. Lists EO in must demonstrate continuous compliance with Group I. each operating limit and work practice standard required under this section, except during Table 2 — Organic Hazardous Air Pollutants. periods of startup, shutdown, and malfunction. Lists EO. .364 — Lists monitoring requirements. Table 4 — Organic Hazardous Air Pollutants Provides specific requirements for sterilization Subject to Cooling Tower Monitoring facilities using acid-water scrubbers, catalytic Requirements in Section 63.104. Lists EO. oxidation or thermal oxidation, or through Subpart G — National emission standards the use of another control device. Requires for organic HAPs from the SOCMI for process computation of a 24-hour average daily and vents, storage vessels, transfer operations, and requires installation, calibration, operation, and wastewater. maintenance of a monitor to measure EO. Table 9 — Organic HAPs Subject to the .365 — Lists test methods and procedures for Wastewater Provisions for Process Units at performance testing, efficiency determination New and Existing Sources and Corresponding at the sterilization chamber vent, concentration Fraction Removed (Fr) Values. EO is listed with determination, efficiency determination at an Fr value of 0.98. the aeration room vent (not manifolded), determination of baseline parameters for acid-water scrubbers, and compliance demonstration.

.366 — List reporting, construction and Table 2 — Lists EO as a partially soluble HAP. reconstruction, and notification requirements. Table 8 — Lists 1.0 as the fraction measured (Fm) .367 — Owners or operators of a source for EO in wastewater streams. subject to Section 63.362 must comply with the .1423 — recordkeeping requirements in Section 63.10(b) and (c). All records required to be maintained “Epoxide” is defined as a chemical must be maintained so that they can be readily compound consisting of a three-membered accessed and are suitable for inspection. The cyclic ether. Only emissions of epoxides most recent two years of records must be listed in Table 4 of this Subpart, including retained onsite or be accessible to an inspector EO, are regulated by the provisions of this while onsite. The records of the preceding three Subpart (Subpart PPP, Sections 1420-1439). years, where required, may be retained offsite. “Extended Cookout (ECO)” is defined Records may be maintained in hard copy or as a control technique that reduces the computer-readable form including on paper, amount of unreacted EO and/or propylene microfilm, computer, computer disk, magnetic oxide (epoxides) in the reactor. This is tape, or microfiche. accomplished by allowing the product to react for a longer time period, thereby .368 — EPA or authorized authority, such as the applicable state, local, or tribal agency, can having less unreacted epoxides and implement and enforce this Subpart. reducing epoxides emissions that may have otherwise occurred. Subpart U — NESHAPs: Group I polymers and resins. Subpart PPP — Known organic HAPs from polyether polyol products. .482 — “Epichlorohydrin elastomer” is defined as an elastomer formed from the polymerization Table 4 — Lists EO as a known organic HAP or copolymerization of epichlorohydrin (EPI). from polyether polyol products. The main epichlorohydrin elastomers include Subpart EEEE — NESHAPs: Organic liquids epi-ethylene oxide (EO) copolymer. Epoxies distribution (non-gasoline). produced by the copolymerization of EPI and Table 1 — Lists EO as an organic HAP. bisphenol A are not epichlorohydrin elastomers. Subpart FFFF — NESHAPs: Miscellaneous — Known organic HAPs emitted from Table 5 organic chemical manufacturing. the production of elastomer products. Table provides elastomer products/subcategories for Table 8 — Lists EO as a partially soluble HAP. listed chemicals, including EO. Subpart UUUU — NESHAPs for cellulose Subpart DD — NESHAPs from off-site waste and products manufacturing. recovery operations. .5480 — Lists EO as one of the HAPs emitted Table 1 — EO is included on the list of HAPs, in greatest quantity from cellulose products with a Method 305 fraction measure factor manufacturing operations. (fm 305) of 1.0. .5610 — Subpart JJ — National emission standards for “Cellulose ether process” is defined to wood furniture manufacturing operations. include a manufacturing process that Table 2 — List of volatile HAPs (VHAP). EO is includes the following process steps: (i) included. reaction of cellulose with sodium hydroxide to produce alkali cellulose; (ii) reaction of the — Pollutants excluded from use in Table 4 alkali cellulose with a chemical compound(s), cleaning and washoff solvents. EO is listed. such as EO, to produce a particular cellulose Table 6 — VHAP of potential concern. EO is ether; (iii) washing and purification of listed with 0.09 tons per year de minimis value. the cellulose ether; and (iv) drying of the cellulose ether. Subpart GGG — National emission standards for pharmaceuticals production.

“Extended cookout (ECO)” is defined may be safely used as a fumigant for the control to include as a cellulose ether process of microorganisms and insect infestation in change that reduces the amount of one of ground spices and other processed natural several unreacted chemicals, including EO, seasoning materials, except mixtures to which leaving the reactor. This is accomplished by salt has been added, in accordance with allowing the product to react for a longer prescribed conditions. time, thereby leaving less unreacted EO and .910 — Residues of listed materials are reducing emissions of EO that might have exempted from the requirement of a tolerance occurred otherwise. when used in accordance with good Subpart XXXX — NESHAPs: Rubber Tire agricultural practice as inert or occasionally Manufacturing active ingredients in pesticide formulations applied to growing crops or to raw agricultural Table 16 — EO is listed as a selected HAP. commodities after harvest. Inert ingredients Subpart GGGGG — NESHAPs: Site remediation include mixtures produced using EO, and

Table 1 — EO is listed with an fm305 (fraction mixtures containing EO. measure factor in Method 305, 40 CFR Part 63, .920 — Listed materials are exempted from Appendix A) of 1.0. the requirement of a tolerance when used in Subpart HHHHH — NESHAPs: Miscellaneous accordance with good agricultural practice coating manufacturing. as inert or occasionally active ingredients in pesticide formulations applied to growing Table 7 — EO is included on the list of partially crops only. Inert ingredients include mixtures soluble HAPs in wastewater that are subject to produced using EO, and mixtures containing management and treatment requirements EO. 40 CFR Part 68 — Chemical accident prevention — Listed materials are exempted from provisions. .930 the requirement of a tolerance when used in .130 — accordance with good agricultural practice Table 1 — List of regulated toxic substances as inert or occasionally active ingredients in and TQs for accidental release prevention. pesticide formulations applied to animals. Inert EO is listed with a TQ of 10,000. EO was ingredients include mixtures produced using listed based on the following: EO, and mixtures containing EO. (a) Mandated by congress; and .940 — Lists pesticide chemicals that, when used as ingredients in an antimicrobial (b) On EHS list, vapor pressure 10mm Hg or pesticide formulation, may be applied to dairy greater. processing equipment, and food-processing Table 2 — List of regulated toxic substances equipment and utensils. Pesticide chemicals and TQs for accidental release prevention. include mixtures produced using EO, and EO is listed with a TQ of 10,000. EO was mixtures containing EO. listed based on the following: .960 — Residues resulting from the use of (a) Mandated by congress; and the listed polymers as inert ingredients in a (b) On EHS list, vapor pressure 10mm Hg or pesticide chemical formulation are exempted greater. from the requirement of a tolerance, if such use is in accordance with good agricultural or Appendix A — Table of toxic endpoints. EO is manufacturing practices. EO is included as a listed with toxic endpoint of 0.09 mg/L. substance used to create a listed polymer. 40 CFR Part 180 — Tolerances and exemptions .1001 — from tolerances for pesticide chemicals in food. (c) Residues of the listed materials are .151 — Establishes tolerances for residues of the exempted from the requirement of a “antimicrobial agent and insecticide” EO, when tolerance when used in accordance with used as a postharvest fumigant in or on copra good agricultural practice as inert or coconut, whole spices, and black walnuts. EO occasionally active ingredients in pesticide

formulations applied to growing crops or to Under waste code U115 with technology raw agricultural commodities after harvest. codes (WETOX or CHOXD) fb CARBN or Listed inert ingredients include mixtures CMBST, or concentration 0.12 mg/L in produced using EO, and mixtures containing wastewater, and technology codes CHOXD EO. or CMBST in nonwastewater. (d) Listed materials are exempted from the .48 — Lists universal waste treatment standards. requirement of a tolerance when used in Includes EO, and the listed wastewater standard accordance with good agricultural practice is a concentration of 0.12 mg/L in wastewater. as inert or occasionally active ingredients in 40 CFR Part 302 — Designations, reportable pesticide formulations applied to growing quantities and notification requirements for crops only. Listed inert ingredients include CERCLA hazardous substances. mixtures produced using EO, and mixtures containing EO. .4 — Lists EO as a hazardous substance under CAA Section 112 and Section 3001 of (e) Listed materials are exempted from the the Resource Conservation and Recovery Act requirement of a tolerance when used in (RCRA) with a final reportable quantity of 10 accordance with good agricultural practice pounds. as inert or occasionally active ingredients in pesticide formulations applied to animals. Appendix A — Sequential CAS Registry Number Listed inert ingredients include mixtures list of CERCLA hazardous substances. Includes produced using EO, and mixtures containing EO. EO. 40 CFR Part 355 — Emergency planning and notification. 40 CFR Part 261 — Identification and listing of hazardous waste. Appendix A — The list of extremely hazardous substances and their threshold planning .33(f) — EO is listed as U115 (U list waste). quantities. EO is listed with a reportable Appendix VIII — EO is included on the list of quantity (RQ) of 10 pounds and a threshold hazardous constituents list. planning quantity of 1,000 pounds. There is a 40 CFR Part 266 — Standards for the note for EO: “Chemicals on the original list that management of specific hazardous wastes and do not meet toxicity criteria but because of their specific types of hazardous waste management high production volume and recognized toxicity facilities. are considered chemicals of concern (‘Other chemicals’).” Appendix V — Risk specific dosages (risk specific doses (10-5). EO is listed with a unit risk Appendix B — The list of extremely hazardous of 1.0E-04 m3/µg and an RsD of 1.0E-01 µg/ m3. substances and their threshold planning quantities. EO is listed with an RQ of 10 pounds Appendix VII — Nonmetals: Residue concentration limits. EO is listed with a and a threshold planning quantity of 1,000 concentration limit for residues of 3xE-04 mg/kg. pounds. There is a note for EO: “Chemicals on the original list that do not meet toxicity 40 CFR Part 268 — Land disposal restrictions. criteria but because of their high production .40 — Lists treatment standards for volume and recognized toxicity are considered hazardous wastes. Includes waste code, chemicals of concern (‘Other chemicals’).” waste description and treatment/regulatory 40 CFR Part 372 — Toxic chemical release subcategory, regulated hazardous constituent, reporting: Community right-to-know. and concentrations in wastewater, and nonwastewater. EO is listed as follows: .65 — EO is listed effective January 1, 1987. Under waste code F039 as a regulated 40 CFR Part 414 — Organic chemicals, plastics, hazardous constituent, with a concentration and synthetic fibers. of 0.12 mg/L in wastewater; and .60(a) — EO is included on list of aliphatic organic chemicals.

40 CFR Part 721— Significant new uses of chemical .50-10(q) — The special requirements for EO substances. contained in Section 151.50–12 must also be observed. .3680 — SNUR requirements for EO adduct of fatty acid ester with pentaerythritol. The .50-12 — significant new use is release to water. (a) .3700 — SNUR requirements for fatty acid, (1) EO shall be carried in fixed, independent, ester with styrenated phenol, EO adduct. pressure vessel type cargo tanks, The significant new uses are the hazard designed, constructed, arranged and, if communication program and release to water. necessary, equipped with machinery to .3800 — SNUR requirements for formaldehyde, maintain the cargo temperature below condensated polyoxyethylene fatty acid, 90°F except as otherwise provided for in ester with styrenated phenol, EO adduct. paragraph (a)(3) of this section. The significant new uses are the hazard (2) EO shall be loaded at a temperature communication program and release to water. below 70°F. .7000 — SNUR requirements for polymer (3) When EO is to be transported at or near of disodium maleate, allyl ether, and EO. atmospheric pressure, the Commandant The significant new uses are the hazard may permit the use of alternate methods communication program and industrial, of storage which are consistent with the commercial, and consumer activities. minimum requirements of this subpart. Shipping — USCG (b) 46 CFR Part 150 — Compatibility of cargoes. (1) All cargo tanks shall be constructed of a carbon steel or stainless steel acceptable Table 1 — The alphabetical list of cargoes to the Commandant. Impurities of copper, includes chemical name, group number, magnesium and other acetylide-forming footnote, CHRIS code, and related CHRIS codes. metals shall be kept to a minimum. The EO is included on the list, and is in group 0, with chemical composition of all steel used footnote 1, and CHRIS code EOX. EO, propylene shall be submitted to the Commandant oxide mixture is also listed, and it is in group 16, for approval prior to fabrication. footnote 1, CHRIS code EPM. Aluminum, copper and other acetylide- Table 2 — This table lists the grouping of forming metals, such as silver, mercury, cargoes. EO is included in group 0, unassigned magnesium, and their alloys shall not cargoes. EO, propylene mixtures are included in be used as materials of construction for group 16, alkylene oxides. tanks or equipment used in handling EO. 46 CFR Part 151 — Barges carrying bulk liquid (2) Cargo tanks shall meet the requirements hazardous material cargoes. of Class I pressure vessels. Table 151.05 to Subpart 151.05 — Summary (3) Cargo tanks shall be designed for the of Minimum Requirements. The Table lists maximum pressure of vapor or gas used requirements for cargo identification, hull type, in discharging the cargo but in no case cargo segregation tank, tanks, cargo transfer, shall the design pressure of such tanks environmental control, fire protection, special be less than 75 pounds per square inch requirements in 46 CFR Part 151, electrical gauge. The tank shell and heads shall not hazard class and group, temperature control be less than 5⁄16-inch thick. installation, and tank internal inspection period. (c) EO is included in the Table. (1) Cargo tanks shall be located below deck .50-10(a) — For the purpose of this part, in holds or enclosed spaces with the alkylene oxides are considered to be EO and domes or trunks extended above the propylene oxide. weather deck and terminating in the open. Provisions shall be made to maintain the

watertightness of the deck by means of (2) An alternate arrangement may consist watertight seals around such domes or of three cooling plants, any two of trunks. The holds or enclosed spaces, in which shall be sufficient to maintain the which the EO tanks are located, shall not temperature of the liquid cargo at or be used for any other purpose. However, below the design temperature of the in open hopper type barges of a suitable system. design approved for such service, the (3) Cooling systems requiring compression weatherdeck may not be required to be of EO are prohibited. watertight. (f) In addition to the shutoff valve required, all (2) All cargo tanks shall be installed tank connections larger than one-half inch with the manhole openings and all inside pipe size, except safety relief valves tank connections located above the and liquid level gauging devices, shall be weatherdeck in the open. fitted with either internal back pressure (3) Tanks shall be electrically bonded to the check valves or internal excess flow valves hull. in conjunction with a quick closing stop (4) No welding of any kind shall be done valve operable from at least two remote on cargo tanks or supporting structure locations. The quick closing stop valve shall unless authorized by the Commandant. be of the ‘‘fail safe’’ type acceptable to the Commandant and shall be equipped with a (d) All cargo tanks, piping, valves, fittings, fusible plug designed to melt between 208°F and similar equipment which may contain and 220°F, which will cause the quick closing ethylene oxide in either the liquid or vapor valve to close automatically in case of fire. phase, including the vent risers, shall be The quick closing valve shall be located as insulated. Flanges need not be covered, close to the tank as possible. but if covered, a small opening shall be left at the bottom of the flange cover to detect (g) Piping systems intended for EO service leaks. Insulation shall be of an approved shall not be used for any other product incombustible material suitable for use with and shall be completely separate from all EO, which does not significantly lower the other systems. The piping system shall be autoignition temperature and which does not designed so that no cross connections may react spontaneously with EO. The insulation be made either through accident or design. shall be of such thickness as to provide a (h) Each safety relief valve shall be set to start thermal conductance of not more than 0.075 to discharge at not less than 75 pounds per B.t.u. per square foot per degree Fahrenheit square inch gauge, nor more than the design differential in temperature per hour. pressure of the tank. (e) (i) The filling density shall not exceed 83 (1) When cooling systems are installed to percent. maintain the temperature of the liquid (j) below 90°F, at least two complete (1) The cargo shall be shipped under a cooling plants, automatically regulated by suitable protective inerting gas system, temperature variations within the tanks such as nitrogen. When nitrogen gas shall be provided; each to be complete is used, the gas inerting system shall with the necessary auxiliaries for proper be so designed that the vapor space operation. The control system shall also above the liquid cargo will be filled and be capable of being manually operated. maintained with a gas mixture of not An alarm shall be provided to indicate less than 45 percent nitrogen. Other malfunctioning of the temperature gases proposed for inerting use may be controls. The capacity of each cooling given consideration by the Commandant. system shall be sufficient to maintain the Original charging only of protective temperature of the liquid cargo at or below inerting gas at the loading facility is not the design temperature of the system.

considered adequate. A sufficient amount .22(a)(8) — To obtain an endorsed Certificate of spare inerting gas as approved by the of Compliance to meet Section 154.1802(a) for Commandant shall be provided on the a foreign flag vessel, whose flag administration vessel in order to maintain the proper issues IMO Certificates, and an endorsement concentration of the gas in the event of for the carriage of EO, an application must normal leakage or other losses. be submitted to the USCG that includes a (2) Any inerting gas selected should be at classification society certification that the least 98 percent pure and free of reactive vessel meets the requirements of Section materials, such as ammonia, hydrogen 154.1725(a)(4), (5), and (7). sulfide, sulfur compounds, and acetylene. .1705(a) — EO must be carried in an (k) Prior to loading, a sample from the cargo independent tank type C that meets Section tank will be taken to insure that the pad gas 154.701(a). will meet the requirements of paragraph (j) .1710 — When a vessel is carrying EO, the of this section and that the oxygen content master must ensure that air is purged from the of the vapor space will be not more than 2 cargo tanks and associated piping before the percent maximum. If necessary, a sample cargo is loaded. The mast must also ensure that will be taken after loading to insure the the air is excluded after the cargo is loaded by vapor space meets this requirement. maintaining a positive pressure of at least 13.8 (l) The cargo piping shall be inspected and kPa gauge (2 psig) by either introducing a gas tested at least once in each two calendar that is not reactive; is not flammable; and does years. not contain more than 0.2percent oxygen by volume; or by controlling the cargo temperature. (m) In those cases where the cargo transfer hose used is not part of the barge’s .1720 — A refrigeration system that is used equipment, the person in charge of the to cool EO must be an indirect refrigeration transfer operation shall determine that the system that does not use vapor compression. provisions of Section 151.50–10(k) have been .1725 — met before using this hose. A certificate (a) A vessel carrying EO must: of test, supplied by the transfer facility, will be considered as adequate for this (1) Have cargo piping, vent piping, and determination. refrigeration equipment that have no connections to other systems; (n) The provisions of Section 151.50–10 shall be complied with as a requirement for shipping (2) Have valves, flanges, fittings, and EO. accessory equipment made of steel, stainless steel, except types 416 and 442, (o) A hydrostatic test of 11⁄2 times the design or other material specially approved by pressure shall be made on the cargo tanks the Commandant (G–MSO); at least once in each four years at the time the internal examination is made and at such (3) Have valve disk faces, and other wearing other times as considered necessary by the parts of valves made of stainless steel Officer in Charge, Marine Inspection. containing not less than 11 percent chromium; 46 CFR Part 154 — Safety standards for self- propelled vessels carrying bulk liquefied gases. (4) Have gaskets constructed of spirally wound stainless steel with teflon or .7 — other material specially approved by the “Flammable cargoes” is defined to include Commandant (G–MSO); several liquefied gases, including EO, from (5) Not have asbestos, rubber, or cast iron Table 4 (follows Section 154.1872). components in the cargo containment “Toxic cargoes” is defined to include several system and piping; liquefied gases, including EO, from Table 4 (6) Not have threaded joints in cargo piping; (follows Section 154.1872).

(7) Have a water spray system under Section Transportation — Research and Special 154.1105 that protects the above deck Programs Administration cargo piping; and 49 CFR Part 172 — Hazardous materials (8) Have a nitrogen inerting system or on table, special provisions, hazardous materials board nitrogen gas storage that can inert communications, emergency response the vapor space of an EO cargo tank for a information, and training requirements. period of 30 days under the condition of .101 — Hazardous materials table. This table paragraph (e) of this section. lists the proper shipping name, hazard class or (b) The cargo hose used for EO must: division, identification number, packing group, (1) Be specially approved by the label code, special provisions, packaging Commandant (G–MSO); and requirements, quantity limitations, and vessel stowage requirements for hazardous materials. (2) Be marked ‘‘For (Alkylene or Ethylene) The table includes EO and carbon dioxide Oxide Transfer Only.’’ mixture with more than 87 percent EO; EO (c) EO must be maintained at less than 30°C and carbon dioxide mixtures with more than (86°F). 9 percent but not more than 87 percent EO; EO (d) Cargo tank relief valves for tanks containing and carbon dioxide mixtures with not more than EO must be set at 539 kPa gauge (78.2 psig) 9 percent EO; EO and chlorotetrafluoroethane or higher. mixture with not more than 8.8 percent EO; EO and dichlorodifluoromethane mixture, (e) The vapor space of a cargo tank carrying with not more than 12.5 percent EO; EO and EO must be maintained at a nitrogen pentafluoroethane mixture with not more concentration of 45 percent by volume. than 7.9 percent EO; EO and propylene oxide (f) A vessel must have a method for jettisoning mixtures, with not more than 30 percent EO; EO that meets the requirements of Sections EO and tetrafluoroethane mixture with not more 154.356 and 154.1872. than 5.6 percent EO; EO or EO with nitrogen .1730 — up to a total pressure of 1MPa (10 bar) at 50 degrees C. (a) The master must ensure that before EO is loaded into a cargo tank: Table 1 to Appendix A — List of hazardous substances and RQs. EO is included, and the (1) The tank is thoroughly clean, dry, and free RQ for EO is 10 pounds (4.54 kg). of rust; .102 — List of non-refrigerated liquefied (2) The hold spaces are inerted with an compressed gases subject to portable tank inert gas that meets the requirements of code T50. Includes EO with nitrogen up to a Section 154.1710(b)(1); and total pressure of 1MPa (10 bar) at 50°C; EO (3) The cargo tank vapor space is inerted and carbon dioxide mixture with more than with nitrogen. 9 percent but not more than 87 percent EO; (b) EO must be off loaded by a deepwell pump EO and dichlorodifluoromethane mixture or inert gas displacement. with not more than 12.5 percent EO; EO and chlorotetrafluoroethane mixture, with not more (c) EO must not be carried in deck tanks. than 8.8 percent EO; EO and pentafluoroethane .1872(d) — When EO is carried, the master must mixture, with not more than 7.9 percent EO; ensure that the emergency jettisoning piping and EO and tetrafluoroethane mixture, with not with associated pumps and fittings is on-line more than 5.6 percent EO. and ready for use for an emergency. Table 4 — Provides summary of minimum requirements for several cargoes, including EO.

49 CFR Part 173 — Shippers— general metal receptacle must be capable of requirements for shipments and packagings. withstanding no less than a 1241.1 kPa (180 psig) burst pressure. No more than .304a(a) — Liquefied gases (except gas in solution) must be offered for transportation, 12 receptacles may be packed in one box, subject to the requirements in this section and and each receptacle may not be liquid full Sections 49 CFR Sections 173.301 and 173.304, below 82°C (180°F). Each inner receptacle except that no DOT 4E or 39 packaging may be must be insulated and equipped with filled and shipped with a mixture containing EO, a relief device of the fusible plug type unless specifically authorized in this Part. with yield temperature of 69°C to 77°C (156°F to 171°F). The capacity of relief .323 — device and insulation must be such that (a) For packaging EO in non-bulk packagings, the charged receptacle will not explode silver mercury or any of its alloys or copper when tested by the method described in may not be used in any part of a packaging, CGA Pamphlet C–14 or other equivalent valve, or other packaging appurtenance method. Each completed package must if that part, during normal conditions of be capable of passing all Packing Group I transportation, may come in contact with EO performance tests. liquid or vapor. Copper alloys may be used (4) In specification cylinders, as authorized only where gas mixtures do not contain free for any compressed gas except acetylene at any concentration that will form acetylene. Pressurizing valves and copper acetylene. All packaging and gaskets insulation are required for cylinders over must be constructed of materials which are 4 L (1 gallon) capacity. Eductor tubes compatible with EO and do not lower the must be provided for cylinders over 19 L auto-ignition temperature of EO. (5 gallons) capacity. Cylinders must be (b) EO must be packaged in one of the seamless or welded steel (not brazed) following: with a nominal capacity of no more than 115 L (30 gallons) and may not be liquid (1) In 4G fiberboard boxes with inner glass full below 82°C (180°F). Before each ampoules or vials. Total quantity of EO refilling, each cylinder must be tested for may not exceed 100 grams (3.5 ounces) leakage at no less than 103.4 kPa (15 psig) per package. The completed package pressure. In addition, each cylinder must must be capable of passing Packing be equipped with a fusible type relief Group I performance tests. device with yield temperature of 69°C to (2) In 4G fiberboard boxes constructed with 77°C (157°F to 170°F). The capacity of the top and bottom pads and perimeter liner. relief device and the effectiveness of the Inner packagings must be aluminum insulation must be such that the charged receptacles of no more than 135 g cylinder will not explode when tested by (4.8 ounces) capacity cushioned with the method described in CGA Pamphlet incombustible material. No more than C–14 or other equivalent method. 12 receptacles may be packed in one (5) In 1A1 steel drums of no more than 231 L box, and no more than 10 boxes may (61 gallons) and meeting Packing Group I be overpacked under the provisions performance standards. The drum must of Section 173.25 of this part. Each be lagged, of all welded construction completed package must be capable of with the inner shell having a minimum passing Packing Group I performance thickness of 1.7 mm (0.068 inches) tests. and the outer shell having a minimum (3) In 4C1, 4C2, 4D or 4F wooden boxes thickness of 2.4 mm (0.095 inches). or 4G fiberboard boxes with inner Drums must be capable of withstanding metal receptacles of no more than a hydrostatic test pressure of 690 kPa 340 g (12 ounces) capacity. The (100 psig). Lagging must be of sufficient

thickness so that the drum, when filled (e) In determining outage, consideration must with ethylene oxide and equipped with be given to the lading temperature and the required pressure relief device, will solubility of inert gas padding in EO as well not rupture when exposed to fire. The as the partial pressure exerted by the gas drum may not be liquid full below 85°C padding. (185°F), and must be marked ‘‘THIS (f) Each tank, loaded or empty, must be padded END UP’’ on the top head. Before each with dry nitrogen or other suitable inert gas refilling, each drum must be tested for of sufficient quantity to render the vapor leakage at no less than 103 kPa (15 psig) space of the tank nonflammable up to 41°C pressure. Each drum must be equipped (105°F). The gas used for padding must be with a fusible type relief device with free of impurities which may cause the EO yield temperature of 69°C to 77°C (157°F to polymerize, decompose or undergo other to 170°F), and the capacity of the relief violent chemical reaction. device must be such that the filled drum is capable of passing, without rupture, the (g) Copper, silver, mercury, magnesium or their test method described in CGA Pamphlet alloys may not be used in any part of the C–14 or other equivalent method. tank or appurtenances that are normally in contact with the lading. (c) When Section 172.101 of this subchapter specifies that a hazardous material be (h) Neoprene, natural rubber and asbestos packaged under this section, only the gaskets are prohibited. All packing and following bulk packagings are authorized, gaskets must be made of materials which subject to the requirements of subparts A do not react with or lower the autoignition and B of this part, the special provisions temperature of the lading. specified in column 7 of the Section 172.101 (i) Each tank must be insulated with cork (at table, and paragraphs (d) through (j) of this least 10 cm (4 inches) thick), or mineral section: wool, fiberglass or other suitable insulation (1) Tank cars. Class DOT 105J tank cars: material of sufficient thickness so that the Notwithstanding the requirements of thermal conductance at 16°C (60°F) is not Section 173.31(c), each tank car must have more than 0.075 Btu per hour per square a tank test pressure of at least 20.7 Bar foot per degree F. temperature differential. (300 psig) no later than July 1, 2006. Portable tanks made and in use prior to December 31, 1987, equipped with fusible (2) Cargo tanks. Specification MC 330 and plugs instead of a pressure relief valve or MC 331 cargo tank motor vehicles. rupture disc, must have sufficient insulation (3) Portable tanks. DOT 51 portable tanks. so that the tank as filled for shipment will not (d) The pressure relief devices must be set to rupture in a fire. The insulation on portable function at 517 kPa (75 psig). Portable tanks tanks or cargo tank motor vehicles must fitted with non-reclosing devices made be protected with a steel jacket at least and in use prior to December 31, 1987, may 2.54 mm (0.100 inch) thick, or as required by continue to be used in EO service. the specification. (j) Tank car tanks built after December 30, 1971, must be equipped with a thermometer well.

Appendix A Figures and Tables

Figure 1 EthyleneEthylene Oxide Oxide Liquid Liquid Densit Densityy

55 3

50 Lbs/F t

40 0 40 80 120 160 200 240 Temperature, °F

Figure 2 Ethylene Oxide Vapor PressurePressure

1000

100 a Psi

1 0 40 80 120 160 200 240 Temperature, °F

Figure 3 Ethylene Oxide Liquid Heat CapacityCapacity

0.56

0.52

0.48 F BTU/Lb*°

0.44

0.40 0 40 80 120 160 200 240

Temperature, °F

Figure 4 EthyleneEthylene Oxide Oxide LiquidLiquid ViscositViscosityy

0.40

0.35

0.30

0.25 Centipois e

0.20

0.15

0.10 0 40 80 120 160 200 240 Temperature, °F

Figure 5 EthyleneEthylene OxideOxide LiquidLiquid ThermalThermal ConductivitConductivityy

0.10

0.09

0.08 BTU/Ft*Hr* ° F

0.07

0.06 0 40 80 120 160 200 240 Temperature, °F

Figure 6 EthyleneEthylene OxideOxide HeatHeat ofof VaporizatioVaporizationn

275

250

225 b BTU/L

200

175 0 40 80 120 160 200 240 Temperature, °F

Figure 7 EthyleneEthylene OxideOxide VaporVapor HeatHeat CapacitCapacityy

0.4

IDEAL GAS SATURATED EO VAPOR

0.3 ° F BTU/Lb*

0.2 0 40 80 120 160 200 240 Temperature, °F

Figure 8 Ethylene Oxide Vapor ViscosityViscosity

0.013

0.012

0.011

Centipois e 0.010

0.009

0.008 0 40 80 120 160 200 240

Temperature, °F

Figure 9 Ethylene Oxide Vapor Thermal ConductivityConductivity

0.014

0.013

0.012

0.011

0.010

0.009

BTU/Ft*Hr* ° F 0.008

0.007

0.006

0.005

0.004 0 40 80 120 160 200 240 Temperature, °F

Figure 10 FreezingFreezing PointsPoints EthyleneEthylene Oxide/WaterOxide/Water MixturesMixtures

48 Pure EO Freezing point – 170°F

36 Freezing Point, ° F Point, Freezing

24 0 20 40 60 80 100 Ethylene Oxide in Water, wt%

Figure 11 Cp/C/Cvv ForFor Saturated Saturated Ethylene Ethylene Oxide Oxide Vapor Vapor

1.32

1.31

1.30

1.29

1.28

o Rati 1.27 v / C p 1.26 C

1.25

1.24

1.23

1.22 0 50 100 1 50 200 250 300 Temperature, °F

Figure 12 Ethylene OxideOxide VaporVapor DensityDensity

2.5

2.0

1.5 3 Lbs/F t 1.0

0.5

0.0 0 40 80 120 160 200 240 Temperature, °F

Figure 13 Ethylene Oxide CoeﬃcientCoefficient of ofCubic Cubic Expansio Expansionn

0.0017

0.0015

0.0013

0.0011

Coeﬃcient of Cubic Expansion per ° F 0.0009

Temperature, °F

0.0007 0 40 80 120 160 200 240

this page intentionally left blank

Figure 14 Raoult’s Law Deviation Factors for Ethylene Oxide/Water Mixtures Terminal Regions are Expanded in the Next Figure

10 psia 9 Where: 1 7 yi = mol fraction (EO or water) in 35 gas phase 8 xi = mol fraction (EO or water) in 45 liquid phase Di = Raoult's Law Deviation Factors 55 7 from Figures 14 and 15 65 (no units) (vp)i = pure component vapor pressure at system temperature 6 Pt = total system pressure ***

yi Pt Di = xi (vp)i

4 i D

psia Water 65 Ethylene Oxide 35

1 0 0. 2 0. 4 0. 6 0. 8 1.0 Mole Fraction Ethylene Oxide in Water *** Any pressure units can be used, so long as the unites for vapor pressure and total pressure are the same.

Figure 15 Raoult’s Law Deviation Factors for Ethylene Oxide/Water MixturesMixtures

Mole Fraction Ethylene Oxide in Water 0.94 0.96 0.98 1.00 14

Where: yi = mol fraction (EO or water) in gas phase xi = mol fraction (EO or water) in liquid phase Di = Raoult's Law Deviation Factors from Figures 14 and 15 12 (no units)

(vp)i = pure component vapor O pressure at system temperature 2 H Pt = total system pressure psia *** D 65 10

yi Pt Di = xi (vp)i

psia 17

7 35 45 55 65 O E 6 D

4 0 0.02 0.04 0.06 0.08 0.10 Mole Fraction Ethylene Oxide in Water *** Any pressure units can be used, so long as the unites for vapor pressure and total pressure are the same.

Figure 16 Flammability Data on EO-Air Mixtures at Subatmospheric PressuresPressures

800

700

600

500

400

300

200 Pressure, millimeters Hg, absolute Pressure,

100

0 0 10 20 30 40 50 60 70 80 90 100 Percent Ethylene Oxide in Air

FigureFigure 1717 VVapor/Liquidapor/Liquid EquilibriaEquilibria ofof EthEthyleneylene OOxide/Waterxide/Water SySystemsstems

1.00

0.90

0.80

0.70 xide

0.60 ylene O

0.50 tion Eth tion

0.40

ac apor Mole Fr 0.30 V

0.20

0.10

0.00 0.00 0.10 0.20 0.30 0.40 0.50 0.60 0.70 0.80 0.90 1.00 Liquid Mole Fraction Ethylene Oxide

FigureFigure 1818 DensityDensity vs. vs. Composition Composition of of Eth Ethyleneylene O Oxide/Waterxide/Water Sy Systemsstems

1.02

1.00

0.98

0.96 cc

g/ y, 0.94 Densit

0.92

0.90

0.88

0.86 0 10 20 30 40 50 60 70 80 90 100 110 120 Ethylene Oxide, percent by weight

FigureFigure 1919 BoilingBoiling pointspoints ofof aqueousaqueous EOEO concentrationsconcentrations

120 212

192

100 172

80 152

132

60 112 Temperature, ºF Temperature, ºC

40 92

20 52

0 32 0 10 20 30 40 50 60 70 80 90 100 Ethylene Oxide, by Weight Percentage

Figure 20 DecompositionDecomposition DataData

200

180

Decomposed 160 Did Not Decompose

140

120

100

0 450 460 470 480 490

Figure 21 Vapor Vapor CompressibilityCompressibility vs.vs. PressurePressure asas aa FunctionFunction ofof TemperatureTemperature

1.02

1.00

60°F

0.98

0.96

0.94

0.92

0.90 0 20 40 60 80 100 120

Table A1 Physical Property Equations

EQUATION COEFFICIENTS (ALL PROPERTIES IN SI UNITS)

PROPERTY UNITS A B C D E USABLE RANGE EQUATIONS

MIN°K MAX°K

Solid Density KgMOL/M3 2.75E+01 161 Y = A + (B*T) +(C*T^2) + (D*T^3) + (E*T^4)

Liquid Density KgMOL/M3 1.8360E+00 2.6024E-01 4.6915E+02 2.6960E-01 161 469 Y = A/(B^(1+(1-T/C)^D))

Coeff of Expansion per°K 2.6024E-01 4.6915E+02 2.6960E-01 161 469 Y= (-D/C)*LN(B)*((1-T/C)^ (D-1))

Vapor Density KgMOL/M3 3.3904E+00 -5.0556E-02 2.9019E-04 -7.6743E-07 7.9840E-10 233 383 Y= A + (B*T) + (C*T^2) + (D*T^3) + (E*T^4)

Vapor Pressure Pa 9.1944E+01 -5.2934E+03 -1.1682E+01 1.4902E-02 1.0000E+00 161 469 Y = exp (A + (B/T) +(C*InT) + (D*T^E))

Heat of Vaporization J/KgMOL 3.6652E+07 3.7878E-01 161 469 Y = A*((1-Tr)^(B + (C*Tr) + (D*Tr^2) + (E*Tr^3)))

Solid Heat Capacity J/KgMOL*°K -2.1143E+04 1.4903E+03 -1.1881E+01 3.8745E-02 25 161 Y= A + (B*T) + (C*T^2) + (D*T^3) + (E*T^4)

Liquid Heat Capacity J/KgMOL*°K 1.4471E+05 -7.5887E+02 2.8261E+00 -3.0640E-03 161 284 Y= A + (B*T) + (C*T^2) + (D*T^3) + (E*T^4)

Ideal Gas Heat Capacity J/KgMOL*°K 3.3460E+04 1.2116E+05 1.6084E+03 8.2410E+04 7.3730E+02 50 1500 Y = A + B*((C/T)/SINH (C/T)) ^2 + D*((E/T)/COSH(E/T))^2

Second Virial Coefficient M3 KgMOL 6.0016E-02 -5.2057E+01 -1.8056E+07 6.9368E+19 -1.7212E+00 235 1500 Y = A +(B/T) + (C/T^3) +(D/T^8) +(E/T^9)

Liquid Viscosity Kg/M*S -8.5210E+00 6.3502E+02 -3.3140E-01 161 284 Y = exp (A + (B/T) +(C*InT) + (D*T^E))

Vapor Viscosity Kg/M*S 2.9540E-06 4.7120E-01 7.874E0+02 -2.3580E+04 161 1000 Y = (A*T^B) / (1 + (C/T) + (D/T^2))

Liquid Thermal Conductivity W/M*°K 2.6957E-01 -3.9840E-04 161 284 Y= A + (B*T) + (C*T^2) + (D*T^3) + (E*T^4)

Vapor Thermal Conductivity W/M*°K -3.7880E+04 1.1150E+00 -5.6410E+03 273 1000 Y = (A*T^B) / (1 + (C/T) + (D/T^2))

Surface Tension N/M 7.4730E-02 1.1410E+00 161 469 Y = A*((1-Tr)^(B + (C*Tr) + (D*Tr^2) + (E*Tr^3)))

Note: The symbol * denotes multiplication. The symbol ^ denotes exponentiation. T is temperature, deg Kelvin. Tr is reduced temperature, T/T critical

Table A2 Conversion Factors

To Convert From To Multiply By Notes

KgMOL/M3 Lb/Gal 0.3676 1

Pascals Lbf/sq in .445E-04

J/KgMOL BTU/Lb 9.785E-06 1

J/KgMOL*°K BTU/Lb*°F 5.422E-06 1

KgM*S Centipoise 1E+03

W/M*°K BTU/Ft*Hr*°F 0.578

N/M Lbf/ft 6.852E-02

Notes: 1. Only valid for Ethylene Oxide