EPA Releases Draft Exposure Assessments For Trans‑1,2‑Dichloroethylene And 1,2‑Dichloropropane

The U.S. Environmental Protection Agency (EPA) announced on July 31, 2026, that it is advancing its review of trans‑1,2‑dichloroethylene and 1,2‑dichloropropane under the Toxic Substances Control Act (TSCA) “by releasing draft technical support documents that explain how the agency estimates exposure to these common solvents.” According to EPA, “[e]valuating potential risks from these solvents is important because they are widely used in industry and may be present in consumer products and can travel through air and water, leading to possible exposures at work, at home, and in nearby communities.” Under TSCA, EPA is required to consider potentially exposed or susceptible subpopulations, which can include workers, pregnant women, infants and children, and people who live near where these chemicals are used.

EPA states that the draft exposure assessments show how it uses the best available science to understand the potential releases of these chemicals into the environment and how people might come into contact with them. The draft assessments describe each chemical’s properties; how they move and break down in air, water, and soil; where releases may occur; and what that means for potential exposure to workers, consumers, the general public, and wildlife. The draft assessments combine measured data and established models to estimate exposures through multiple pathways, such as workplace air, indoor air, drinking water, and surface water, and explain the assumptions and uncertainties behind those estimates. EPA notes that the documents are drafts and do not make final risk conclusions.

The draft documents include:

• trans-1,2-Dichloroethylene: EPA’s draft exposure assessment for trans-1,2-dichloroethylene characterizes releases to air, water, and land and evaluates potential occupational, consumer, general population, and environmental exposures associated with the manufacture, processing, laboratory activities, disposal, and reasonably foreseen industrial, commercial, and consumer uses of the chemical.

• 1,2-Dichloropropane: EPA’s draft exposure assessment for 1,2-dichloropropane characterizes releases to air, water, and land and evaluates potential occupational, consumer, general population, and environmental exposures associated with manufacturing, processing, laboratory activities, disposal, and reasonably foreseen industrial, commercial, and consumer uses of the chemical.

EPA states that the draft exposure technical support documents “are intended to provide stakeholders with insight into the scientific methods and data that support EPA’s draft risk evaluations.” According to EPA, the draft documents will be available for public comment in their respective TSCA public review dockets “at a later date” once EPA releases the draft risk evaluations. At that time, EPA “will welcome public review and comment” before preparing the final risk assessments for these chemicals. Scientific analyses of human health and environmental effects of these chemicals underwent independent peer review by the Science Advisory Committee on Chemicals (SACC) during a meeting from August 3 through 7, 2026.

EPA notes that all current protections for these chemicals remain in place while EPA completes its review and that releasing draft scientific analyses does not alter any existing safeguards. EPA states that its findings and conclusions may change based on feedback received during the public comment period and based on external peer review of the underlying science.

Commentary

It is regrettable that EPA is releasing parts of its risk evaluation in a way that the full, draft risk evaluation is not available for SACC review. We recognize the significant time pressure EPA is under to complete risk evaluations to satisfy its obligations under the court’s consent decree. Nevertheless, because risk evaluations are the scientific underpinning for risk management rules, it is vital that risk evaluations meet the criteria for the best available science and weight of scientific evidence. Lingering scientific weaknesses in a risk evaluation can lead to legal weakness in final risk management rules and invite litigation. The SACC provides crucial external scientific legitimacy to EPA’s conclusions. The absence of the SACC’s review of the complete risk evaluation may invite legal challenge of the final rules. The compressed timeline for EPA to complete its risk evaluations means EPA is having to decide between meeting its obligations under the consent decree or allowing for SACC review of the complete assessment. EPA is in an unenviable position. While we applaud EPA for releasing the draft exposure assessments, the fact that they were released during the SACC meeting last week diminishes the likelihood that the SACC’s commentary and ultimate report will reflect careful consideration on the exposure side. Nonetheless, we are hopeful that the SACC’s review of the separate hazard and exposure evaluations will allow EPA to produce a well-constructed, scientifically justified risk evaluation for these solvents and the other chemicals EPA is required to complete under the consent decree.