In September 2025, EPA proposed significant revisions to Toxic
Substances Control Act (TSCA) risk evaluation framework for
existing chemicals that “rescind or revise” key
elements of the framework that were finalized in May 2024 under the
Biden Administration. Most notably, regarding EPA's
evaluation under TSCA Section 6 as to whether an existing chemical
presents an unreasonable risk of injury to health or the
environment, the proposed rule abandons the “whole chemical
approach” adopted under the May 2024 rule that required a
single risk determination for all conditions of use, in favor of
the previous approach under the Trump Administration, which
requires a risk evaluation for each condition of use. In addition,
the proposed rule again allows EPA to assess workplace exposure
risks assuming under most circumstances use of compliant personal
protective equipment. The proposed rule also reinstates the
definition of “weight of scientific evidence” and,
consistent with
