The U.S. Environmental Protection Agency (EPA) announced on June 17, 2026, that it is advancing its review of five chemicals under the Toxic Substances Control Act (TSCA) — 1,1,2-trichloroethane; 4,4′-(1-methylethylidene)bis[2,6-dibromophenol] (TBBPA); 1,2-dichloropropane; ethylene dibromide; and trans-1,2-dichloroethylene — by sending the underlying science to the Science Advisory Committee on Chemicals (SACC) for peer review and opening it for public comment. EPA states that “[t]hese chemicals appear in flame retardants, cleaning and degreasing products, leaded aviation gasoline, laboratories, and industrial processes, so EPA’s conclusions can directly affect the air Americans breathe at home, at work, and in their communities.” EPA released technical support documents supporting the draft risk evaluations for four of these chemicals on June 17, 2026. As reported in our June 17, 2026, memorandum, EPA released the draft risk evaluation and supporting documents for TBBPA on June 12, 2026, for public comment. Draft documents related to all five chemicals are available for public comment and independent scientific peer review in SACC docket EPA-HQ-OPPT-2026-2246 at http://www.regulations.gov — “two essential steps in ensuring the integrity, radical transparency, and quality of EPA’s chemical safety assessments.”
EPA states that the documents released show:
- Ethylene dibromide (also called 1,2-dibromoethane) is used mainly as a lead scavenger in leaded aviation gasoline, where it manages lead deposits in piston-engine aircraft. EPA notes that this means the Agency “is examining it in the broader context of lead exposure, including around airports and in communities near where it is handled.” EPA’s draft material identifies workplace exposures from import, repackaging, fuel-related uses, laboratory work, and waste handling, along with potential exposures through air, drinking water, surface water, fish, consumer uses, and other environmental pathways.
- trans-1,2-Dichloroethylene is used in cleaning and degreasing and in industrial and commercial products. EPA’s draft documents evaluate non-cancer and environmental hazards and lay out EPA’s full evaluation of the cancer evidence through the weight-of-evidence approach.
- 1,1,2-Trichloroethane is a volatile organic compound (VOC) used primarily as an intermediate in the production of other organic chemicals. EPA states that the draft technical support materials evaluate human and ecological hazards of 1,1,2-trichloroethane, highlighting respiratory, immune, neurological, and liver effects as key non-cancer concerns, evidence of carcinogenicity, and risks to aquatic and terrestrial species. The exposure assessment characterizes releases, fate/transport, and exposures across occupational, consumer, general population, and environmental pathways, concluding that air is the primary exposure pathway given the chemical’s properties and release patterns.
- 1,2-Dichloropropane is a chlorinated solvent that evaporates easily into the air. EPA’s draft hazard identified potential cancer and non-cancer health concerns, including nervous system effects (such as drowsiness) and damage to the lining of the nose.
EPA notes that it “is paying particular attention to the people most at risk — workers with the heaviest exposures, pregnant women, children, and communities living near sources — and welcomes comment on how real-world exposures should be reflected.” EPA emphasizes that the documents are drafts and do not represent final Agency determinations regarding the risks posed by these chemicals. Following the close of the public comment period and completion of peer review, EPA will carefully consider all input before preparing final risk evaluations in accordance with TSCA requirements.
August 2026 Peer Review Meeting
On August 3-7, 2026, EPA will hold a virtual public meeting of SACC to review the draft technical support documents for these five chemicals. In advance of the August meeting, EPA will also hold a preparatory virtual public meeting on July 23, 2026, for SACC and the public to consider and ask questions regarding the scope and clarity of the draft charge questions that will be used in the peer review meeting. EPA states that it will publish registration links for the July preparatory meeting and August SACC meeting on the SACC website approximately one month prior to each meeting. The draft documents and draft charge questions are available in the peer review docket EPA-HQ-OPPT-2026-2246 at www.regulations.gov. SACC will consider comments on the draft technical support documents and draft charge questions that are submitted by July 23, 2026.
EPA states that it will release draft risk evaluations for 1,1,2-trichloroethane; 1,2 dichloropropane; ethylene dibromide; and trans-1,2-dichloroethylene prior to the August SACC meeting. EPA notes that because of the unique and novel scientific approaches used in the human health and environmental assessments for these chemicals, however, it “is only seeking peer review from the SACC on the draft technical document[s] released today. EPA anticipates that the draft risk evaluations for these chemicals will use scientific approaches and techniques the SACC has previously commented on; therefore, EPA does not expect the need for an additional peer review of the forthcoming risk evaluations.”
Commentary
EPA’s rationale for sending only components of a TSCA risk evaluation for peer review is likely to feel familiar to those who have tracked the program’s implementation since the 2016 Lautenberg amendments. EPA employed a similar approach, for example, for the phthalate risk evaluations, where the SACC did not peer review the full draft risk evaluation, instead only reviewing certain technical support documents that would support those evaluations. In reality, the condensed peer review scopes for recent chemical evaluations may have been viewed as necessary to meet aggressive court-ordered deadlines. Nonetheless, this approach has been the topic of fierce debate and criticism, with many arguing that relegating the independent peer review process to component pieces — rather than the whole — risks undermining the completeness of the advice and shielding EPA from scrutiny on the more consequential analytical leaps. Although EPA would counter that scientific methodologies that have already been vetted should not require re-vetting every time they are applied, there remains a question as to whether application of those methods to the specific chemical at issue and the ultimate characterization of the chemical’s risks is itself a scientific judgment that warrants independent review. One might argue that independent scientific review was built into the statute precisely because Congress understood that risk evaluations can be enormously consequential — forming the legal and scientific basis for risk management rules that can restrict or ban uses of chemicals across wide swaths of the economy — and that those conclusions should not be self-certifying.
As America marks 250 years of a successful system built on careful checks and balances, it is worth asking whether the TSCA peer review process — as currently implemented — reflects those same principles. Our founders did not send partial drafts to the Continental Congress in 1776 and promise everything else would work out. Likewise, the TSCA regulated community and public deserve completeness in the review of decisions that can directly or indirectly impact our lives and livelihoods in lasting and significant ways.