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.