On June 12, 2026, the U.S. Environmental Protection Agency (EPA) released its draft risk evaluation for 4,4′-(1-methylethylidene)bis[2, 6-dibromophenol] (TBBPA) under the Toxic Substances Control Act (TSCA). EPA states in its press release that “[u]sing gold standard science — including real-world monitoring data and modeling — the draft identifies unreasonable risk to workers from inhalation exposure (three conditions of use [COU]) and unreasonable risk to the environment from releases to surface water during certain processing and disposal activities (two [COUs]). The draft did not find unreasonable risk to consumers or the general population.” On June 16, 2026, EPA published a Federal Register notice announcing the availability of the draft risk evaluation and beginning a 60-day comment period. 91 Fed. Reg. 36138. According to EPA, the public comment period “is a critically important step, it is how EPA hears from independent experts, workers, communities, and the public so that the final evaluation reflects the largest possible universe of gold standard science and is fully protective.” EPA notes that it “specifically welcomes additional data, including local monitoring and biomonitoring, information on potentially exposed or susceptible subpopulations (such as fenceline communities and Tribes with high fish consumption), and information on cumulative exposure to multiple flame retardants.” Comments are due on or before August 17, 2026.
What Is TBBPA?
EPA states in the Federal Register notice that TBBPA is a crystalline solid used as an additive and reactive flame retardant. According to EPA, as an additive flame retardant, TBBPA is incorporated into polymers and used in electronic enclosures and electronic consumer products with an outer plastic casing. As a reactive flame retardant, TBBPA is primarily used in epoxy resin printed circuit boards. TBBPA is used in fabric, textile, leather products, and construction materials. EPA notes that workers may be exposed to TBBPA through inhalation of dust or dermal contact during the manufacturing, processing, use, or disposal of TBBPA. Consumers may be exposed to TBBPA through dermal or oral exposure to products, as well as inhalation of dust. EPA states that TBBPA is primarily released to the environment through land disposal, although environmental release can also occur through air and water releases. According to EPA, TBBPA has been found in drinking water, ground water, ambient air, indoor air, fish, human breast milk, and dust and soil.
Request for Comment
EPA states that it welcomes specific input on each section of the draft risk evaluation, particularly input on the following:
- Non-cancer human health hazard conclusions (e.g., selection of intermediate and chronic endpoints);
- Cancer human health hazard conclusions (e.g., conclusion of non-genotoxic mode of action and preliminary cancer classification);
- Exposure assumptions for occupational exposure scenarios (e.g., how exposure controls and personal protective equipment (PPE) are used, the frequency of occupational task(s) per shift, use of respirators with an Assigned Protection Factor (APF) higher than ten during higher exposure tasks);
- Modeling assumptions for COUs without Toxics Release Inventory (TRI) data (e.g., use as a laboratory chemical);
- Domestic manufacturing as a reasonably foreseen use and any information regarding domestic manufacturing being reestablished in the United States;
- Information that may inform assessment of water releases and environmental impacts (e.g., percent of TBBPA in waste disposal streams); and
- Relevant studies or other data sources not identified by EPA.
Next Steps
After EPA considers comments received from the public on the draft risk evaluation and input from the Science Advisory Committee on Chemicals (SACC) peer review, it will issue a final risk evaluation. Under TSCA Section 6, EPA must determine in the final risk evaluation, based on the weight of scientific evidence, whether the chemical presents an unreasonable risk to human health or the environment under the chemical’s COUs. EPA states that this includes consideration of risks to potentially exposed susceptible subpopulations who may be at greater risks than the general population, such as children and workers. EPA notes that TSCA prohibits it from considering non-risk factors (e.g., costs/benefits) during risk evaluation.
Commentary
EPA’s progress continued in meeting the requirements in the consent decree, with the final risk evaluation for TBBPA and nine other chemicals due in February 2027. EPA has identified unreasonable risk to aquatic species from some high-end water releases during processing activities. How EPA might choose to manage such risks remains unclear, as EPA has yet to propose a risk management rule to protect against chemicals it has identified as a risk to aquatic species. EPA may follow its policies from the TSCA New Chemicals Program and impose a surface water concentration limit, in which case releases above that limit would be prohibited. EPA also identified risk to unprotected workers during manufacturing (in the high-end exposure scenario) and repackaging of powder (for both central tendency and high-end scenarios). Based on EPA estimates, respiratory protection could be used to protect against the identified exposures. EPA did not identify unreasonable risk to consumers, which may draw some criticisms from environmental and public health groups. EPA’s analysis assumed, however, that the cumulative surface area of all TBBPA-containing electronic articles encountered by a consumer is the entire floor surface area of a median household — an extraordinarily conservative approach. EPA also found no unreasonable risk for flight crews or airplane passengers, even when using very conservative assumptions about exposures on board aircraft. Likewise, environmental exposures from drinking water and fish ingestion were orders of magnitude below EPA’s concern threshold.
If EPA’s risk assessment and conclusions remain the same at the final risk evaluation stage, the analysis suggests that EPA will have to impose a surface water concentration limit to protect against risk to aquatic species and a workplace chemical protection plan with an occupational exposure limit for inhalation exposure. The risk calculations do not seem to support banning any particular use of TBBPA.
