Defining Risk: EPA Seeks Major TSCA Chemical Evaluation Reforms

On Sept. 23, 2025, the U.S. Environmental Protection Agency (EPA) proposed highly anticipated amendments to the procedural framework rule for conducting existing chemical risk evaluations under the Toxic Substances Control Act (TSCA). When conducting a TSCA existing chemical risk evaluation, EPA must determine whether a chemical substance presents an unreasonable risk of injury to health or the environment, without considering costs or non-risk factors under the conditions of use (COU).

As discussed below, this rule is highly important because it will define the risk framework for evaluating the use conditions of existing chemicals undergoing TSCA risk evaluation for years to come. The result of this process will determine whether the chemical use will continue, be regulated (and if so, how) or deemed to pose an unreasonable risk and discontinued.

Proposed Amendments

The proposal includes many proposed amendments to the 2024 final risk evaluation rule to address targeted changes to EPA’s process for conducting TSCA risk evaluations. The new administration noted months ago that it was revisiting the Biden administration’s approach to risk evaluation, many key provisions of which are disfavored by the industrial chemical community. Many industrial stakeholders believe the current approach is unduly conservative, inconsistent with the plain meaning of TSCA and does not reflect the most reasonable interpretation of TSCA.

At the heart of the existing framework rule are three provisions that are the subject of controversy. First, the proposal would end the “whole chemical” determination approach under which EPA makes a single determination of unreasonable risk for the chemical as a whole if a single COU is determined to pose an unreasonable risk. The proposal restores the practice of making an unreasonable risk determination for each COU.

Second, EPA is proposing to remove provisions requiring EPA to evaluate every COU and every exposure pathway, denying EPA discretion to decide otherwise.

Third, the proposal would end the presumption that occupational controls are not used and clarify how EPA will consider occupational exposure controls, such as personal protective equipment (PPE) and industrial controls, when conducting risk evaluations and making risk determinations. The proposal addresses many other issues, but these three are the most important.

Discussion

The legal underpinnings of the single determination/whole chemical approach have been vigorously contested in court and opposed since the policy was implemented in the Biden administration. The whole chemical approach classifies a chemical as posing “unreasonable risk” if a single COU, however discrete, is found to pose unreasonable risk. This approach is prejudicial to all other uses of the chemical and, some contend, misrepresents the chemical’s true utility and value.

The presumption that PPE and workplace controls do not adequately protect workers, or are insufficient, or are not faithfully followed, is, some argue, not grounded in fact. The existing risk framework rule does not consider exposure reduction based on the use of PPE on the theory that consistent use cannot be assumed, and there are gaps in the U.S. Occupational Safety and Health Administration’s (OSHA) coverage. Many claim this is contrary to law, inconsistent with record evidence, and thus a violation of TSCA.

The change in EPA’s assumptions about exposures that result from pathways regulated by other authorities, such as the Clean Air Act and Safe Drinking Water Act, was also expected. As with OSHA protection, EPA is proposing to evaluate exposures from those pathways, assuming compliance with those programs. EPA acknowledges that a substance undergoing risk evaluation may not be restricted by another statute. In that case, EPA would reasonably assume no control under the proposal.

Importantly, EPA seeks comment on whether it should define “reasonably foreseen.” This is a crucial question for which stakeholders are encouraged to provide their comments. From 2017 to 2021, EPA took the position that “Reasonably foreseen conditions of use will not be based on hypotheticals or conjecture.” EPA no longer includes this explanation in its determination documents. Rather, EPA’s New Chemicals Program tends to view anything that it has not reviewed as being foreseeable, tending to ignore the term “reasonably.”

This proposal goes a long way in rightsizing the risk framework rule. Stakeholders are encouraged to comment on key issues. How EPA assesses the risk of existing chemicals will have a significant impact on their continued use and thus on industrial operations writ large. The past five years have been a learning experience for many.

The existing chemicals reviewed under TSCA Section 6 have been subject to rigorous regulation, which has diminished their use and led to significant changes in the manufacturing sector. In some instances, change was clearly needed, but not in all cases, and not on the legal theory advanced by the EPA. This proposal should correct the imbalance, and commenting on it is recommended.