DETERMINATION ON WHETHER A SUBSTANCE IS A HAZARDOUS SUBSTANCE PURSUANT TO SECTION 26 OF THE HSNO ACT

Application Code HAZ03010 Application Type Section 26 – determine whether a substance is hazardous under the HSNO Act. Applicant Plastics New Zealand (Inc) Date Application Received 20 August 2003 To be considered by The Hazardous Substances Standing Committee of the Authority. Purpose of the Application To determine whether expandable poystyrene beads are hazardous.

Applications Advisor (Operations Noel McCardle Group)

Scientific Advisor (Science & Tania van Maanen Analysis Group)

Introduction

Polystyrene is a hard, brittle, clear polymer, used to make such things as CD cases, cosmetics bottles, food containers and similar. Expandable polystyrene (EPS) is a resin consisting primarily of polystyrene (min 91%) with the addition of various blowing agents (eg pentane, butane). EPS beads are typically 0.2 – 3.0 mm in diameter and are made either by suspension polymerisation in the blowing agent, or by impregnating standard polystyrene with the blowing agents in pressurized vessels.

EPS beads are converted to a lightweight rigid foam by expansion and subsequent steam moulding. In the first step, the small rigid beads are heated which causes the blowing agent to vaporise out resulting in the foaming the polymeric beads. These expanded beads, commonly referred to as “pre-puff” have a volume up to 40 times larger than the pre- expanded EPS beads. The “pre-puff” is then subjected to steam heat in a mould, where the expanded beads fuse together to form the moulded product. These expanded foam products have many applications, e.g for use as a packaging material, in egg cartons, drink cups, meal trays, building insulation and padding.

Substance Definition

For the purposes of this section 26 determination, expandable polystyrene (EPS) beads are defined as solid polymers comprising a minimum of 91 % polystyrene and a maximum of 9 % of any of the blowing agents listed below, in any combination.

ERMA New Zealand section 26 determination HAZ03010 Page 1 of 8 Component Name CAS number Composition

Base polymer polystyrene 9003-53-6 Min 91%

(Mw >10,000)

Any combination of blowing n-pentane 109-66-0 agents as listed: cyclopentane 287-92-3

isopentane 78-78-4 Max 9% Butane 106-97-8

isobutane 75-28-5

Propane 74-98-6

Hazardous Property Assessment

The base polymer, polystyrene does not trigger any of the HSNO thresholds (refer HAZ03006, previous s26 determination). Any potential hazards associated with EPS beads will therefore be due to the presence of the blowing agents. It is noted that, as pure substances, all the blowing agents (as listed in the substance definition above) trigger at least one HSNO threshold, as discussed below.

Hazard Classifications of Individual Components

A summary of the hazard classifications triggered by each blowing agent is provided below:

Name CAS Flammability Acute Skin Eye Ecotoxicity toxicity irritation irritation n-pentane 109-66-0 3.1B 6.1E 6.3B 6.4A 9.1D aspiration 9.74mg/l hazard cyclopentane 287-92-3 3.1B 6.1E 6.3B 6.4A 9.1C aspiration 10.5mg/l hazard (persistent) isopentane 78-78-4 3.1A 6.1E 6.3B 6.4A 9.1D aspiration 2.3mg/l hazard butane 106-97-8 2.1.1A - - - - isobutane 75-28-5 2.1.1A - - - - propane 74-98-6 2.1.1A - - - (persistent)

ERMA New Zealand section 26 determination HAZ03010 Page 2 of 8 Hazard Classification of EPS Beads

Taking the hazard classification(s) and maximum possible concentration of the blowing agents into account, the hazardous property assessment for EPS beads is provided below.

Class 1: Explosiveness None of the components as listed in the substance definition above are explosive as defined by the HSNO criteria. It is therefore considered that EPS beads as defined above do not trigger this threshold.

Class 2, 3, 4: Flammability Classes 2 and 3 relate to flammable gases, flammable aerosols and flammable liquids and are not relevant to EPS beads which are solid. With respect to Class 4, flammable solids, the applicant notes that EPS beads are not classified in the UNRTDG (United Nations Recommendations on the transport of Dangerous Goods) as class 4 substances and therefore concludes that EPS beads do not trigger HSNO class 4 (the test criteria for HSNO class 4 are directly comparable to UN class 4). However, the applicant acknowledges that EPS contains up to 9 % of a flammable blowing agent which may over time vapourise out of the polymer, especially at elevated temperatures. The UN has recognised this out-gassing of vapour poses a flammability risk during transport and has therefore assigned “expandable, polymeric beads evolving flammable vapour” (UN2211) a class 9 classification. [The UN Class 9 classification (miscellaneous dangerous substances and articles) is assigned to substances that present a danger during transport that is not covered by other UN classes]. It is noted that there is no equivalent “miscellaneous” category in the HSNO classification scheme. Therefore, as the EPS beads do not trigger HSNO class 4, they are not classified as flammable solids under HSNO. They will, however, be subject to national and international transport controls and to workplace requirements under HS&E. In addition, it is noted that the blowing agents are, as pure substances, currently controlled by the Dangerous Goods legislation as provided by the HSNO transitional provisions.

Class 5: Oxidisers/Organic Peroxides None of the components as listed in the substance definition above are oxidisers as defined by the HSNO criteria. It is therefore considered that EPS beads as defined above do not trigger this threshold.

Class 6: Toxicity Sub-class 6.1 – Acute Oral, Dermal and Inhalation Toxicity Acute Oral Toxicity

The applicant acknowledges that three of the possible blowing agents (n-pentane, cyclopentane, isopentane) have been classified as 6.1E based on aspiration hazard*. However, as the EPS beads are solids, they do not present an aspiration hazard and a 6.1E classification is therefore not appropriate.

It is noted that none of the blowing agents are classified as acute oral toxicants on the basis of LD50 values. As such, EPS beads as defined above will not trigger the threshold for this endpoint.

ERMA New Zealand section 26 determination HAZ03010 Page 3 of 8 * Aspiration is the introduction of liquid into the lungs which may result in lung damage. It is almost always an accidental process involving a single dose and it may occur directly or indirectly. Direct aspiration occurs when liquids 'go down the wrong way', i.e. they enter the respiratory tract rather than the digestive tract and so find their way to the lungs. Indirect aspiration occurs when low viscosity liquids are swallowed, vomiting occurs and the vomitus enters the respiratory tract.

Acute Dermal and Inhalation Toxicity

The project team note that none of the possible blowing agents have acute dermal or inhalational toxicities that would cause the EPS beads to be classified in these endpoints.

Summary of Acute Toxicity

The project team agree with the applicant’s conclusion that EPS beads do not trigger the threshold for acute toxicity.

Subclass 6.3 – Skin Irritation Subclass 6.4 – Eye Irritation The applicant acknowledges that three of the possible blowing agents have been classified as both 6.3B skin irritants and 6.4A eye irritants (n-pentane, cyclopentane, isopentane). However, the applicant points out that the maximum concentration that these components will be present in the EPS beads is 9%, which is below the 10 % concentration cut-off for classification of a mixture in these endpoints (refer ERMA New Zealand User Guide to HSNO Thresholds and Classifications, Table 3, Part VI, page 32). As a result, the applicant considers that the EPS beads do not trigger the HSNO threshold for either skin or eye irritation. The applicant further notes that the blowing agents will, to some degree, be encapsulated in the polymer matrix and application of the standard mixture rules results in an overly conservative estimate of toxicity. The project team agree with the applicant’s conclusion that EPS beads do not trigger the threshold for skin or eye irritation.

Subclass 6.5 – Contact and Respiratory Sensitisation The applicant notes that there is no information to show that any of the components as listed in the substance definition above are contact or respiratory sensitisers. The project team agrees that EPS beads as defined above do not trigger this threshold.

Subclass 6.6 – Mutagenicity Subclass 6.7 – Carcinogenicity Subclass 6.8 – Reproductive/Developmental Toxicity The applicant notes that there is no information to show that any of the components as listed in the substance definition above have any of these chronic toxicity properties. The project team agrees that EPS beads as defined above do not trigger any of these thresholds.

Subclass 6.9 – Target Organ Systemic Toxicity The applicant notes that there is no information to show that any of the components as listed in the substance definition above would trigger this threshold and therefore considers that the EPS beads do not trigger this threshold.

ERMA New Zealand section 26 determination HAZ03010 Page 4 of 8 The project team agrees that none of the blowing agents have been classified as 6.9 toxicants via either the oral, dermal or inhalational routes. It is noted that n-pentane and isopentane have been classified by the EU as R67 (vapours may cause drowsiness and dizziness) but it is further noted that there is no equivalent HSNO endpoint for this effect. Indications are that such effects are observed at high concentrations, significantly higher than those typically used for classification in sub-class 6.9 (inhalational route).

It is acknowledged that the inhalation risks to workers posed by EPS beads will be managed by OSH under HS&E legislation. Workplace exposure (WES) values have been set in New Zealand for n- pentane, cyclopentane and butane.

Based on this, the project team agrees with the applicant that EPS beads as defined above do not trigger this threshold.

Class 8: Corrosivity None of the components as listed in the substance definition above are corrosive to metals (sub-class 8.1), skin (sub-class 8.2) or the eye (sub-class 8.3). It is therefore considered that EPS beads as defined above do not trigger this threshold.

Class 9: Ecotoxic Subclass 9.1 - Ecotoxic in the Aquatic Environment The applicant acknowledges that three of the possible blowing agents trigger the 9.1 aquatic ecotoxicity threshold (n-pentane [9.1D], cyclopentane [9.1C] and isopentane[9.1D]. The applicant has calculated the estimated ecotoxicity of EPS beads manufactured with each of these three blowing agents, using both the Summation and Additivity Mixture Rules (refer ERMA New Zealand User Guide to HSNO Thresholds and Classifications, Table 3, Part VII, pages 25-27). Application of the Summation Mixture Rule for EPS beads manufactured with the maximum allowable concentration of each blowing agent (9 %) results in the 9.1 threshold NOT being triggered (greater than 25 % of a 9.1C component is need before this threshold is triggered). Application of the Additivity Mixture Rule using the worst case scenario (9 % isopentane – 2.3 mg/L) gives an estimated ecotoxicity for the EPS beads of 26 mg/L as shown below.

100 = % Component A + % Component B

LC50 mix LC50 Component A LC50 Component B

100 = 9 %

LC50 mix 2.3 mg/L

100 = 3.9

LC50 mix

LC50 mix = 26 mg/L

As isopentane is neither persistent nor bioaccumulative, an ecotoxicity value of 26 mg/L results in a 9.1D classification. However, the applicant considers that strict application of the mixture rules provides for an overly conservative estimate of ecotoxicity as the blowing agent is homogenously dispersed throughout the polymer matrix and as such, will not all be instantly bioavailable. Rather, the applicant asserts that the blowing agent will escape from the polymer matrix over time, and

ERMA New Zealand section 26 determination HAZ03010 Page 5 of 8 considers it unlikely that the solvent will reach a water concentration high enough to trigger the 9.1 threshold. The project team agrees that the mixture rules are designed to be used for mixtures where the constituent components are fully bioavailable, and thus able to elicit a toxic effect that is proportionate to their concentration in the mixture. In this case, all the isopentane would have to be released at once to produce an LC50 of 26 mg/L. The project team agrees that the blowing agent will not be fully bioavailable at once, but will rather “leach” out over time, especially given that isopentane is immiscible in water. The Project Team consider that the rate of out-gassing of isopentane from the EPS beads will be such that it is highly unlikely the aquatic ecotoxicity threshold

(LC50 of 100 mg/L) will be triggered. Therefore, the project team agreees with the applicant’s conclusion that EPS beads do not trigger the threshold for aquatic ecotoxicity.

Subclass 9.2 - Ecotoxic in the Soil Environment Subclass 9.3 - Ecotoxic to Terrestrial Vertebrates Subclass 9.4 - Ecotoxic to Terrestrial Invertebrates There is no information to show that any of the components as listed in the substance definition above are ecotoxic in the soil environment, or ecotoxic to terrestrial vertebrates or invertebrates. It is therefore considered that EPS beads as defined above do not trigger any of these thresholds.

Hazardous Property HSNO Threshold

Explosiveness (Class 1) Not triggered Flammability (Classes 2, 3 and 4) Not triggered Oxidising Capacity (Class 5) Not triggered Toxicity (Class 6)  Acute toxicity Not triggered  Skin irritation Not triggered  Eye irritation Not triggered  Respiratory sensitisation Not triggered  Contact sensitisation Not triggered  Mutagenicity Not triggered  Carcinogenicity Not triggered  Reproductive/developmental Not triggered  Target organ/systemic Not triggered Corrosiveness (Class 8)  Metal Not triggered  Skin Not triggered  Eye Not triggered

ERMA New Zealand section 26 determination HAZ03010 Page 6 of 8 Hazardous Property HSNO Threshold

Ecotoxicity (Class 9)  Aquatic Not triggered  Soil Not triggered  Terrestrial vertebrate Not triggered  Terrestrial invertebrate Not triggered

Other information

EPS beads are not intended for sale to the general public. They will generally only be available in the workplace, specifically plastic manufacturers. Thus, although it is recognised that the blowing agents in the beads may out-gas to produce vapours with some risks (e.g. flammability, health risks via inhalation), it is acknowledged that such risks will be managed by legislation other HSNO, i.e. the Land Transport Rule and HSE.

Recommended Determination

If the Authority is of the view that expandable polystyrene (EPS) beads as defined above are not hazardous under the HSNO Act, then the Authority may: a) determine that expandable polystyrene (EPS) beads as defined above are not hazardous pursuant to section 26 of the HSNO Act 1996; and b) direct the Chief Executive to arrange for notice of this determination to be placed in the Gazette.

Dr Donald Hannah, Manager, Science and Analysis

Date: 29 October 2003

Determination by the Authority

The recommended determination is approved.

Mr Tony Haggerty

Chair Hazardous Substances Standing Committee

Date: 4 January 2004

ERMA New Zealand section 26 determination HAZ03010 Page 7 of 8 Appendix 1

Application form HAZ03010 (attached)

ERMA New Zealand section 26 determination HAZ03010 Page 8 of 8