Public Comment Draft – Do Not Cite or Quote EPA Document# EPA-740-D-21-001 August 2021 United States Office of Chemical Safety and Environmental Protection Agency Pollution Prevention Draft Scope of the Risk Evaluation for Octamethylcyclotetra- siloxane (Cyclotetrasiloxane, 2,2,4,4,6,6,8,8-octamethyl-) (D4) CASRN 556-67-2 August 2021 Public Comment Draft – Do Not Cite or Quote TABLE OF CONTENTS ACKNOWLEDGEMENTS ......................................................................................................................6 ABBREVIATIONS AND ACRONYMS ..................................................................................................7 EXECUTIVE SUMMARY .......................................................................................................................9 1 INTRODUCTION ............................................................................................................................12 2 SCOPE OF THE EVALUATION ...................................................................................................13 2.1 Reasonably Available Information ..............................................................................................13 Search of Gray Literature ...................................................................................................... 14 Search of Literature from Publicly Available Databases (Peer-Reviewed Literature) .......... 14 Search of TSCA Submissions ................................................................................................ 24 2.2 Conditions of Use ........................................................................................................................26 Categories and Subcategories of Conditions of Use Included in the Scope of the Risk Evaluation .............................................................................................................................. 26 Activities Excluded from the Scope of the Risk Evaluation ................................................. 29 Production Volume ................................................................................................................ 30 Overview of Conditions of Use and Life Cycle Diagram ..................................................... 31 2.3 Exposures ....................................................................................................................................33 Physical and Chemical Properties ......................................................................................... 33 Environmental Fate and Transport ........................................................................................ 35 Releases to the Environment ................................................................................................. 36 Environmental Exposures ...................................................................................................... 36 Occupational Exposures ........................................................................................................ 36 Consumer Exposures ............................................................................................................. 37 General Population Exposures ............................................................................................... 38 2.4 Hazards (Effects) .........................................................................................................................39 Environmental Hazards ......................................................................................................... 39 Human Health Hazards .......................................................................................................... 39 2.5 Potentially Exposed or Susceptible Subpopulations ...................................................................40 2.6 Conceptual Models ......................................................................................................................41 Conceptual Model for Industrial and Commercial Activities and Uses ................................ 41 Conceptual Model for Consumer Activities and Uses .......................................................... 43 Conceptual Model for Environmental Releases and Wastes: Potential Exposures and Hazards .................................................................................................................................. 45 2.7 Analysis Plan ...............................................................................................................................47 Physical and Chemical Properties and Environmental Fate .................................................. 47 Exposure ................................................................................................................................ 47 Environmental Releases ..................................................................................................... 48 Environmental Exposures .................................................................................................. 50 Occupational Exposures .................................................................................................... 51 Consumer Exposures ......................................................................................................... 53 General Population ............................................................................................................ 54 Hazards (Effects) ................................................................................................................... 56 Environmental Hazards ...................................................................................................... 56 Human Health Hazards ...................................................................................................... 57 Summary of Risk Approaches for Characterization .............................................................. 59 2.8 Peer Review .................................................................................................................................61 Page 2 of 122 Public Comment Draft – Do Not Cite or Quote REFERENCES .........................................................................................................................................62 APPENDICES ..........................................................................................................................................70 ABBREVIATED METHODS FOR SEARCHING AND SCREENING ................... 70 A.1.1 Search Term Genesis and Chemical Verification ...................................................................70 A.1.2 Publicly Available Database Searches ....................................................................................71 Query Strings for the Publicly Available Database Searches on D4 ...............................72 Data Prioritization for Environmental Hazard, Human Health Hazard, Fate and Physical Chemistry ........................................................................................................75 Data Prioritization for Occupational Exposures and Environmental Releases and Gen Pop, Consumer, and Environmental Exposures .............................................................76 A.2.1 Inclusion/Exclusion Criteria ...................................................................................................77 PECO for Environmental and Human Health Hazards ...................................................77 PECO for Consumer, Environmental, and General Population Exposures. ....................80 RESO for Occupational Exposure and Environmental Releases ....................................81 PESO for Fate and Transport ..........................................................................................83 Generation of Hazard Heat Maps ....................................................................................86 A.3.1 Screening of Gray Literature ..................................................................................................86 A.3.2 Initial Screening of Sources using Decision Logic Tree ........................................................87 A.3.3 TSCA Submission Searching and Title Screening .................................................................88 A.3.4 Gray Literature Search Results for D4 ...................................................................................89 PHYSICAL AND CHEMICAL PROPERTIES OF D4 .............................................. 92 ENVIRONMENTAL FATE AND TRANSPORT PROPERTIES OF D4 ................ 93 REGULATORY HISTORY ........................................................................................ 100 PROCESS, RELEASE, AND OCCUPATIONAL EXPOSURE INFORMATION 105 E.1.1 Manufacture (Including Import) ...........................................................................................105 Domestic Manufacturing ...............................................................................................105 Import ............................................................................................................................105 E.1.2 Processing and Distribution ..................................................................................................105 Reactant or Intermediate ................................................................................................105 Incorporated into a Formulation, Mixture, or Reaction Product ...................................106 Repackaging ..................................................................................................................106