EPA Document# EPA-740-R-20-011 August 2020 United States Office of Chemical Safety and Environmental Protection Agency Pollution Prevention Final Scope of the Risk Evaluation for 1,3-Butadiene CASRN 106-99-0 August 2020 TABLE OF CONTENTS ACKNOWLEDGEMENTS ......................................................................................................................6 EXECUTIVE SUMMARY .....................................................................................................................10 1 INTRODUCTION ............................................................................................................................13 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) .......... 15 Search of TSCA Submissions ................................................................................................ 24 2.2 Conditions of Use ........................................................................................................................25 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 ................................................. 28 Production Volume ................................................................................................................ 29 Overview of Conditions of Use and Lifecycle Diagram ....................................................... 29 2.3 Exposures ....................................................................................................................................31 Physical and Chemical Properties ......................................................................................... 31 Environmental Fate and Transport ........................................................................................ 33 Releases to the Environment ................................................................................................. 33 Environmental Exposures ...................................................................................................... 35 Occupational Exposures ........................................................................................................ 35 Consumer Exposures ............................................................................................................. 36 General Population Exposures ............................................................................................... 36 2.4 Hazards (Effects) .........................................................................................................................37 Environmental Hazards ......................................................................................................... 37 Human Health Hazards .......................................................................................................... 37 2.5 Potentially Exposed or Susceptible Subpopulations ...................................................................38 2.6 Conceptual Models ......................................................................................................................38 Conceptual Model for Industrial and Commercial Activities and Uses ................................ 39 Conceptual Model for Consumer Activities and Uses .......................................................... 41 Conceptual Models for Environmental Releases and Wastes: Potential Exposures and Hazards (Regulatory Overlay) ............................................................................................... 43 2.6.3.1 Exposure Pathways and Risks Addressed by Other EPA Administered Statutes .......... 45 2.6.3.2 Conceptual Model for Environmental Releases and Wastes: Potential Exposures and Hazards 51 2.7 Analysis Plan ...............................................................................................................................53 Physical and Chemical Properties and Environmental Fate .................................................. 53 Exposure ................................................................................................................................ 54 2.7.2.1 Environmental Releases ................................................................................................. 54 2.7.2.2 Environmental Exposures ............................................................................................... 56 2.7.2.3 Occupational Exposures ................................................................................................. 57 2.7.2.4 Consumer Exposures ...................................................................................................... 59 2.7.2.5 General Population ......................................................................................................... 60 Hazards (Effects) ................................................................................................................... 62 2.7.3.1 Environmental Hazards .................................................................................................. 62 2 2.7.3.2 Human Health Hazards ................................................................................................... 63 Summary of Risk Approaches for Characterization .............................................................. 65 2.8 Peer Review .................................................................................................................................66 REFERENCES .........................................................................................................................................67 APPENDICES ..........................................................................................................................................73 ABBREVIATED METHODS FOR SEARCHING AND SCREENING ................... 73 A.1.1 Search Term Genesis and Chemical Verification ...................................................................73 A.1.2 Publicly Available Database Searches ....................................................................................74 A.1.2.1 Query Strings for the Publicly Available Database Searches on 1,3-Butadiene .............74 A.1.2.2 Data Prioritization for Environmental Hazard, Human Health Hazard, Fate and Physical Chemistry .......................................................................................................................79 A.1.2.3 Data Prioritization for Occupational Exposures and Environmental Releases and General Population, Consumer and Environmental Exposures .....................................79 A.2.1 Inclusion/Exclusion Criteria ...................................................................................................80 A.2.1.1 PECO for Environmental and Human Health Hazards ...................................................80 A.2.1.2 PECO for Consumer, Environmental, and General Population Exposures. ....................84 A.2.1.3 RESO for Occupational Exposure and Environmental Releases ....................................84 A.2.1.4 PESO for Fate and Transport ..........................................................................................87 A.2.1.5 Generation of Hazard Heat Maps ....................................................................................90 A.3.1 Screening of Gray Literature ..................................................................................................90 A.3.2 Initial Screening of Sources using Decision Logic Tree ........................................................91 A.3.3 TSCA Submission Searching and Title Screening .................................................................92 A.3.4 Gray Literature Search Results for 1,3-Butadiene ..................................................................93 PHYSICAL AND CHEMICAL PROPERTIES OF 1,3-BUTADIENE..................... 97 ENVIRONMENTAL FATE AND TRANSPORT PROPERTRIES .......................... 99 REGULATORY HISTORY ........................................................................................ 101 PROCESS, RELEASE AND OCCUPATIONAL EXPOSURE INFORMATION 109 E.1.1 Manufacture (Including Import) ...........................................................................................109 E.1.1.1 Domestic Manufacture ..................................................................................................109 E.1.1.2 Import ............................................................................................................................111 E.1.2 Processing and Distribution ..................................................................................................111 E.1.2.1 Reactant .........................................................................................................................111 E.1.2.2 Incorporated into a Formulation, Mixture or Reaction Product ....................................111 E.1.2.3 Incorporated into an Article ...........................................................................................112