Risk Evaluation for 4,4'-(1-Methylethylidene)bis[2, 6-dibromophenol] (TBBPA)
In June 2026, EPA released the draft risk evaluation and associated technical support documents for 4,4'-(1-methylethylidene)bis[2, 6-dibromophenol] (TBBPA) under the Toxic Substances Control Act (TSCA) for public comment and for peer review by the Science Advisory Committee on Chemicals (SACC).
EPA will accept public comments on the draft risk evaluation for 60 days in the TBBPA TSCA docket (EPA-HQ-OPPT-2018-0462) at www.regulations.gov. Comments on the peer review materials will be accepted in the SACC peer review docket (EPA-HQ-OPPT-2026-2246 ) at www.regulations.gov until July 23, 2026.
EPA designated TBBPA as a high priority chemical in December 2019 and the chemical is currently undergoing risk evaluation.
Find other information about other chemicals undergoing risk evaluations under TSCA.
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What is TBBPA?
TBBPA (CASRN 79-94-7) is a white crystalline solid. The primary uses for TBBPA are as a reactant for flame retardants in plastic material and resin manufacturing and as a flame retardant incorporated into electrical equipment. TBBPA is found in electrical and electronic products, batteries, and fabric, textile and leather products, laboratory chemicals, and building/construction materials for commercial and consumer uses, meaning decisions in these cases can directly affect the air we breathe at work and at home. Information from the 2016 Chemical Data Reporting (CDR) for TBBBPA indicates the reported production volume is between 50 million and 100 lbs/year.
Draft Risk Evaluation for TBBPA
EPA’s draft risk evaluation for TBBPA identifies unreasonable risk to workers driven by inhalation exposure (three conditions of use) and unreasonable risk to the environment driven by to releases to surface water during certain processing and disposal activities (two conditions of uses). The draft risk evaluation did not find unreasonable risk to consumers or the general population.
In the draft evaluation, EPA used real-world monitoring data and modeling to assess possible exposure for workers (breathing in dust or vapor and skin contact), consumers (breathing, skin contact, and swallowing), and the general population (drinking water, fish, and soil). EPA also evaluated risks to fish, amphibians, and other aquatic and land organisms and has strong confidence in many of the aquatic risk estimates.
EPA will move quickly, after peer review and public comment, to finalize the risk evaluation. Should EPA continue to find unreasonable risk, EPA will then propose risk management actions to reduce or eliminate these unsafe exposures in workplaces and to the environment.
EPA emphasizes that this evaluation is draft and does not represent final agency determination regarding the risks posed by this chemical. The findings and conclusions may change based on feedback received during the public comment period and peer review process. Additionally, the release of a draft evaluation does not alter or impact any existing protections, regulations, or risk management measures currently in place for these chemicals. All current safeguards remain in place.
Draft Risk Evaluation and Supporting Documents
Read the Federal Register Notice and view the supporting documents in EPA-HQ-OPPT-2018-0462.
- Draft Risk Evaluation for TBBPA (pdf)
- Draft Physical Chemistry and Fate Assessment for TBBPA (pdf)
- Draft Release Assessment for TBBPA (pdf)
- Draft Occupational Exposure Assessment for TBBPA (pdf)
- Draft Consumer and Indoor Dust Exposure Assessment for TBBPA (pdf)
- Draft Environmental Media, General Population, and Environmental Exposure Assessment for TBBPA (pdf)
- Draft Human Health and Environmental Hazard Assessment for TBBPA (pdf)
- Draft Systematic Review Protocol for TBBPA (pdf)
- Data Quality Evaluation and Data Extraction Information for Physical and Chemical Properties for TBBPA (pdf)
- Data Quality Evaluation and Data Extraction Information for Environmental Fate and Transport for TBBPA (pdf)
- Draft Data Quality Evaluation and Data Extraction Information for Environmental Release and Occupational Exposure for TBBPA (pdf)
- Data Quality Evaluation and Data Extraction Information for Dermal Absorption for TBBPA (pdf)
- Data Quality Evaluation Information for General Population, Consumer, and Environmental Exposure for TBBPA (pdf)
- Data Extraction Information for General Population, Consumer, and Environmental Exposure for TBBPA (pdf)
- Data Quality Evaluation Information for Human Health Hazard Epidemiology for TBBPA (pdf)
- Data Quality Evaluation Information for Human Health Hazard Animal Toxicology for TBBPA (pdf)
- Data Quality Evaluation Information for Environmental Hazard for TBBPA (pdf)
- Data Extraction Information for Environmental Hazard and Human Health Hazard Animal Toxicology and Epidemiology for TBBPA (pdf)
- Draft Water Releases for TBBPA (xlsx)
- Draft Land Releases for TBBPA (xlsx)
- Draft Air Releases for TBBPA (xlsx)
- Draft Risk Calculator for Occupational Exposures for TBBPA (xlsx)
- Draft Estimates of Number of Workers and ONUs Model for TBBPA (xlsx)
- Draft Calculations of Dermal Absorption Fluxes for TBBPA (xlsx)
- Draft Use of Laboratory Chemicals OES Environmental Release Modeling Results for TBBPA (xlsx)
- Draft Consumer Exposure Analysis and Risk Calculator for TBBPA (xlsx)
- Draft Surface Water Human Exposure Calculator for TBBPA (xlsx)
- Draft Fish Ingestion Risk Calculator for TBBPA (xlsx)
- Draft Ambient Air IIOAC Results and Risk Calculations for TBBPA (xlsx)
- Draft BMD Modeling Results in the Human Health Hazard Assessment for TBBPA (pdf)