Toxic Substances Control Act (TSCA) Science Advisory Committee on Chemicals (SACC) - Peer Review of 2024 Draft Risk Evaluation for 1,3-Butadiene

March 20, 2025 Alie Muneer Designated Federal Official Office of Program Support Office of Chemical Safety and Pollution Prevention U.S. Environmental Protection Agency Email: muneer.alie@epa.gov Re: ACC 1,3-Butadiene TSCA Risk Evaluation Consortium's Comments on EPA's 1,3-Butadiene Draft Risk Evaluation and Draft Charge Questions (Docket ID EPA-HQ-OPPT-2024-0425) Dear Ms. Muneer: On behalf of the American Chemistry Council (ACC) 1,3-Butadiene TSCA Risk Evaluation Consortium (the Consortium), I am pleased to submit comments to Docket ID EPA-HQ-OPPT-2024-0425 for consideration by the Science Advisory Committee on Chemicals (SACC) and the U.S. Environmental Protection Agency (EPA) as part of the review of the draft risk evaluation for 1,3-Butadiene and its supporting technical documents. The Consortium's comments reflect the best available science and provide a detailed scientific analysis of EPA's approach to hazard characterization, exposure assessment, risk estimation, and regulatory implications. The detailed analysis identifies areas where EPA's methodology may overestimate risks due to overly conservative assumptions and recommends refinements, including the integration of updated epidemiological data, Monte Carlo probabilistic modeling, refined occupational exposure assessments, and improved environmental modeling. In conclusion, EPA has effectively synthesized a substantial body of data in the draft risk assessment for 1,3-BD; however, we have identified key areas for improvement and provided targeted recommendations to enhance scientific rigor and accuracy. The Consortium appreciates EPA's consideration of these comments and those previously submitted under Docket ID EPA-HQ-OPPT-2018-0451, Docket ID EPA-HQ-OPPT-2024-0425, and via the CDX platform. In addition, an updated industrial hygiene report was submitted to the EPA's 1,3-BD SACC docket at this link https://www.regulations.gov/comment/EPA-HQ-OPPT-2024-0425-0076. By implementing the recommended refinements, EPA's final risk evaluation will better align with the best available science, resulting in more accurate risk characterization and effective public health protection. If you have any questions or require further clarification, please do not hesitate to contact me at the email address provided below. Thank you for your time and consideration. Sincerely, Neeraja K Erraguntla, Ph.D.; DABT Director, Chemical Products & Technology Division neeraja_erraguntla@americanchemistry.com

March 15, 2025 Alie Muneer Office of Chemical Safety and Pollution Prevention U.S. Environmental Protection Agency Email: muneer.alie@epa.gov Re: ACC 1,3-Butadiene TSCA Risk Evaluation Consortium's Revised version of the Analysis of 1,3-Butadiene Industrial Hygiene Data Analysis Report submitted to the Docket ID EPA-HQ-OPPT-2024-0425) Dear Ms. Muneer: Enclosed please find a revised version of the Analysis of 1,3-Butadiene Industrial Hygiene (IH) Data Analysis Report previously submitted to EPA's 1,3-Butadiene TSCA Risk Evaluation docket by the American Chemistry Council (ACC) 1,3-Butadiene TSCA Risk Evaluation Consortium (Consortium). The Consortium recently determined that the data point for the Laboratory Technician- nonroutine job group was originally misclassified as a full-shift exposure result, when it represents a short-term duration exposure (i.e., 15 minutes). The IH Data Analysis report has been updated accordingly and, as such, there is no longer full-shift data for non-routine exposure for the laboratory technician job group (see Appendix C). The short-term data point has been added to the short-term dataset for the Sample/Analysis task (<= 15 min) category, non-routine/other group. A revised statistical analysis for this task category has been conducted with the inclusion of the data point (see Appendix D). If you have any questions or require further clarification, please do not hesitate to contact me at the email address provided below. Thank you for your time and consideration. Sincerely, Neeraja Erraguntla, Ph.D.; DABT Director, Chemical Products & Technology Division neeraja_erraguntla@americanchemistry.com

December 18, 2024 Alie Muneer Designated Federal Official Office of Program Support Office of Chemical Safety and Pollution Prevention U.S. Environmental Protection Agency Email: muneer.alie@epa.gov Re: ACC 1,3-Butadiene TSCA Risk Evaluation Consortium's Submission of Additional Materials for Docket ID EPA-HQ-OPPT-2024-0425 Dear Ms. Muneer, The American Chemistry Council (ACC) 1,3-Butadiene TSCA Risk Evaluation Consortium (the Consortium) submits the attached documents to Docket ID EPA-HQ-OPPT-2024-0425 to inform the Science Advisory Committee on Chemicals (SACC) as it reviews the Draft TSCA Risk Evaluation for 1,3-Butadiene. Enclosed, please find the following documents: 1)Updated Hazard Assessment with Responses to EPA Questions 2)A Manuscript Submitted for Publication (In Press): Human Health Risk Assessment for Exposures to 1,3-Butadiene in the United States with Input from an Independent Science Advisory Panel 3)Updated Industrial Hygiene Report with IH Metadata Included in the Appendix On behalf of the Consortium, we appreciate your consideration of these documents in conjunction with those previously submitted to EPA Docket EPA-HQ-OPPT-2018-0451. Should you have any questions or require further clarification, please do not hesitate to contact me directly at the email address provided below. Thank you for your time and attention to this important matter. Sincerely, Neeraja Erraguntla, Ph.D.; DABT Director, Chemical Products & Technology Division neeraja_erraguntla@americanchemistry.com

November 29, 2024 Alie Muneer Designated Federal Official Office of Program Support Re: 1,3-Butadiene; Draft Risk Evaluation Peer Review by the SACC; Request for Comments on Experts Being Considered as Ad Hoc Peer Reviewers; Docket ID EPA-HQ-OPPT-2024-0425 Dear Ms. Muneer, Please find attached the American Chemistry Council (ACC) 1,3-Butadiene TSCA Risk Evaluation Consortium (Consortium) comments on the ad hoc reviewers under consideration for selection to review the 2024 Draft Risk Evaluation for 1,3-Butadiene (Draft Risk Evaluation). On behalf of the Consortium, I appreciate your consideration of these comments. Please feel free to contact me directly at the email address below should you have any questions. Sincerely, Neeraja Erraguntla, Ph.D.; DABT Director, Chemical Products & Technology Division neeraja_erraguntla@americanchemistry.com

Filed on regulations.gov — full text not in the inline record.