EPA Releases Draft Risk Evaluations for trans-1,2-Dichloroethylene and 1,2-Dichloropropane

The U.S. Environmental Protection Agency (EPA) continues to release draft risk evaluations under the Toxic Substances Control Act (TSCA) with the most recent ones released on August 27, 2026 (trans-1,2-dichloroethylene) and September 2, 2026 (1,2-dichloropropane). 91 Fed. Reg. 55337 and 91 Fed. Reg. 56882. EPA states that the purpose of risk evaluations under TSCA is to determine whether a chemical substance presents an unreasonable risk of injury to health or the environment under the conditions of use (COU), including unreasonable risk to potentially exposed or susceptible subpopulations (PESS) identified as relevant to the risk evaluation by EPA, and without consideration of costs or non-risk factors. Comments on the draft risk evaluation for trans-1,2-dichloroethylene are due October 26, 2026. Comments on the draft risk evaluation for 1,2-dichloropropane are due November 3, 2026.

Draft Risk Evaluation for trans-1,2-Dichloroethylene

According to EPA’s August 28, 2026, press release, trans-1,2-dichlorothylene is used in industrial and commercial settings in cleaning and degreasing and as a processing aid, as well as in consumer settings as a cleaner or degreaser and as a propellant in foam insulation. EPA states that it evaluated potential risks across the chemical’s lifecycle since workers and occupational non-users (ONU) may be exposed during manufacturing (import), processing, distribution, industrial use, commercial use, and disposal while consumers may be exposed during cleaning and degreasing activities and as propellants in foam insulation.

EPA states that “[a]s TSCA requires,” it gave particular attention to PESS, such as children and pregnant women, “and, using gold-standard science, including chemical-specific monitoring data, exposure modeling, and the best available scientific information,” identifies significant contributions to unreasonable risk to workers and ONUs from inhalation exposure under 19 COUs. According to EPA, it preliminarily found that one consumer use of trans-1,2-dichloroethylene as a cleaner or degreaser contributes to unreasonable risk based on inhalation exposure. EPA notes that the draft does not identify unreasonable risk to the general population or the environment.

Request for Comment

EPA encourages all potentially interested parties, including individuals, governmental and non-governmental organizations, non-profit organizations, academic institutions, research institutions, and private sector entities, to comment on the draft risk evaluation. To the extent possible, EPA asks commenters to cite any public data related to or that support comments provided, and to the extent permissible, describe any supporting data that are not publicly available. EPA states that it welcomes specific input on each section of the draft risk evaluation, and is particularly interested in:

• Information that may inform exposure assumptions for occupational exposure scenarios (OES) (e.g., whether and how exposure controls and personal protective equipment (PPE) are used for each of the COUs, the frequency of occupational tasks per shift), especially related to the use of trans-1,2-dichloroethylene as a blowing agent;

• Information on the number of facilities involved in the vapor degreasing;

• Information to inform and refine the occupational exposure assessment of the manufacturing as a byproduct OES, including monitoring data;

• Information on the frequency of batch manufacturing within a facility to inform the occupational exposure assessment;

• Additional information on PPE use for the two COUs:
  
  
  • Processing — Incorporation into a formulation, mixture, or reaction product — Solvents (which become part of product formulation or mixture); and
    
    
  • Incorporation into a formulation, mixture, or reaction product — Solvents (for semiconductor manufacturing); and
    

• Other information on any relevant studies or other data sources that were not identified by EPA.

Draft Risk Evaluation for 1,2-Dichloropropane

According to EPA’s September 2, 2026, press release, 1,2-dichloropropane is used in industrial and commercial applications, including as a laboratory chemical and in processing as a reactant. EPA states that 1,2-dichloropropane has been recognized as likely to be carcinogenic to humans, and EPA evaluated both cancer and non-cancer health effects. EPA notes that 1,2-dichloropropane has been used in cleaning and furnishing care products but has not appeared in U.S. manufactured products since 2022. While these uses were phased out in U.S. product formulations four years ago, EPA included these uses in its risk evaluation because products made outside the United States “might still contain the chemical and find their way into American homes and businesses.” EPA welcomes information identifying specific imported products that may contain 1,2-dichloropropane so that these exposures can be considered as the review proceeds.

EPA identifies significant contributions to unreasonable risk to workers and ONUs from inhalation and dermal exposure under 11 COUs. Three consumer uses of 1,2-dichloropropane as a cleaner, polish, or wax were preliminarily found to contribute to unreasonable risk based on inhalation and dermal exposure. EPA notes that, based on the reasonably available information, the draft does not identify unreasonable risk to the general population, including fenceline communities, or to the environment. EPA specifically invites data during the comment period that could inform this preliminary conclusion.

Request for Comment

EPA encourages all potentially interested parties, including individuals, governmental and non-governmental organizations, non-profit organizations, academic institutions, research institutions, and private sector entities, to comment on the draft risk evaluation. To the extent possible, EPA asks commenters to cite any public data related to or that support comments provided, and to the extent permissible, describe any supporting data that are not publicly available. EPA states that it welcomes specific input on each section of the draft risk evaluation, and is particularly interested in:

• Information on whether 1,2-dichloropropane is manufactured as a primary product, or by other manufacturing processes not discussed in the assessment;

• Information on how 1,2-dichloropropane may be distributed for use as a laboratory chemical and in cleaning and furnishing care products;

• Information on the amounts of 1,2-dichloropropane used by commercial laboratories (OES #5) on a daily (kilograms per site per day (kg/site-day)) and yearly (kilograms per site per year) (kg/site-yr)) basis and corresponding PPE and engineering controls to reduce exposures;

• Information on the use of 1,2-dichloropropane in all-purpose liquid cleaner/polish or waxes and polishes — particularly for stone polishing and cleaning — including any information supporting this use as a reasonably foreseen use and any information regarding the use being reestablished in the United States. Information may include: (1) the potential for 1,2-dichloropropane to be utilized in stone waxes, polishes, and cleaners, including but not limited to information on technological or economic factors that indicate this chemical may or may not be utilized in this type of product going forward; (2) any information on application of these products, including method of application, settings, surface area treated, and amounts applied; and (3) inhalation and dermal exposure measurements or alternative modeling approaches that would inform EPA’s assessment of the commercial and consumer scenarios;

• Information to inform and refine the occupational exposure assessment, including monitoring data, worker activities, concentration of 1,2-dichloropropane as it arrives at sites for these OESs, and information on exposure controls and PPE, in particular for the following OESs: Import/Processing-Repackaging (OES #2), Processing Aid (OES #4), Disposal to Incineration (OES #7), Disposal to Landfill (OES #8), and Disposal to publicly owned treatment works (POTW) and Non-POTW wastewater treatment (WWT) (OES #9, #10);

• Information to inform whether the inhalation monitoring data from manufacturing/processing facilities that was used to evaluate occupational exposures for Disposal to Incineration (OES #7), Disposal to POTW/Non-POTW WWT (OESs #9 and 10), and Remediation (OES #11) is representative of these OESs — including information on worker activities (e.g., typical working hours per day and days per year, and PPE use), concentrations of 1,2-dichloropropane in waste streams, and other inhalation monitoring data that could be utilized to assess exposures for these OESs;

• Information that can be used to inform or refine interpretation of occupational exposure estimates for similar exposure groups (SEG) with large variation in occupational exposure concentrations (e.g., the marine logistics technician SEG evaluated under the Processing as a Reactant (OES #3));

• Information on exposure controls and PPE used for each of the COUs, including information on the use of gloves. Specifically, EPA seeks information on prevalence of glove and respirator use, specific tasks for which each is used, glove material, and information on dermal protection programs;

• Information on the effectiveness of glove types for preventing exposures from 1,2-dichloropropane in the context of tasks performed under the COUs — including how workers and their exposure may be affected when using chemically resistant gloves, measured permeation testing of certain types of gloves, and temperature considerations (as identified in the Hand Protection section of the U.S. Occupational Safety and Health Administration’s (OSHA) PPE Guidance and in alignment with the OSHA Hand Protection PPE Standard (29 C.F.R. Section 1910.138)); and

• Other information on any relevant studies or other data sources that were not identified by EPA.

Next Steps

EPA states that after considering public comments on the draft risk evaluations and input from the Science Advisory Committee on Chemicals (SACC) peer reviews, it will issue final risk evaluations. Under TSCA Section 6, EPA must use the final risk evaluation as a basis to determine, 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 notes that this includes risks to subpopulations who may be at greater risks than the general population, such as children and workers. TSCA prohibits EPA from considering non-risk factors (e.g., costs/benefits) during risk evaluation.

Commentary

Overshadowing the release of these draft risk evaluations was the long-awaited decision in the legal challenges to EPA’s TSCA methylene chloride rule and risk evaluation just a few weeks later on September 15, 2026. In a scathing rebuke of EPA’s interpretations, policies, and scientific approaches, the Fifth Circuit vacated both the rule and risk determination and remanded them back to EPA for further consideration. The impacts of the decision in East Fork Enterprises v. EPA (East Fork) on the TSCA program writ large cannot be overstated. See our September 21, 2026, memorandum on East Fork for more on that decision.

EPA has for years now been laser-focused on completing risk evaluations for more than 20 chemicals under a court-ordered schedule stemming from separate litigation. The final milestones in that consent decree — completion of ten final risk evaluations, including those for TDCE and 1,2-dichloropropane — are coming due in February 2027. East Fork may throw EPA’s ability to meet that schedule with final risk evaluations that meet the court’s decision into significant doubt.

On the one hand, the Trump EPA has changed its approach on a number of risk evaluation approaches in ways that move away from application of overly conservative assumptions, that arguably align with the Fifth Circuit’s direction in East Fork. On the other hand, EPA is still operating under the procedural framework for risk evaluations from the Biden era, much of which was directly or indirectly disavowed or repudiated in East Fork. How EPA intends to advance risk evaluations in light of the decision is still an open question.

The questions for EPA are many. One of the questions is in regard to the existing chemicals procedural framework rule. EPA proposed an update to the rule in September 2025 and that proposal included a number of shifts (e.g., use-by-use risk determinations) that would further align risk evaluations with East Fork. Before publishing in final, EPA may need to review its proposal and supplement the preamble and perhaps adjust further the regulatory text on other topics, like assumptions related to use of PPE for workers and the meaning of “unreasonable risk.” Doing so could take some time, especially as EPA continues to absorb and appreciate the magnitude of the East Fork decision. Whether EPA is able to publish the final update to the framework rule before it finishes the remaining ten risk evaluations — before the February 2027 consent decree deadlines — remains to be seen. Navigating these variables is a catch-22 for EPA: Delays could result in breaches of the consent decree, but speed could result in various legal vulnerabilities based on inconsistencies with the current 2024 framework rule or inconsistencies with the East Fork decision.

Perhaps an even more significant question is whether and how EPA will endeavor to update risk evaluations that have already been published in draft — including those for TDCE and 1,2-dichloropropane — and previous risk evaluations that have already been published in final. If significant changes are made to proposed or final risk evaluations, EPA may need to consider whether to publish supplemental draft documents and take another round of public comment. If changes are not made to risk evaluations to bring them in line with the East Fork decision, EPA’s accompanying regulatory actions may be subject to future litigation and potentially suffer the same fate as the methylene chloride rule.