EPA Proposes Changes to TSCA Risk Evaluation Procedures

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On October 30, 2023, EPA published a proposed rule altering the procedures for chemical risk evaluations under section 6 of the Toxic Substances Control Act (TSCA). The proposed rule revises the existing 2017 framework, which was adopted one year after Congress passed amendments to TSCA requiring EPA to evaluate whether existing chemicals that have been identified as “high priority” present an unreasonable risk of injury to health or the environment.

The rulemaking includes the following proposed changes:

  • The clarification that EPA will include all conditions of use (i.e., circumstances under which the chemical is “intended, known, or reasonably foreseen to be manufactured, processed, distributed in commerce, used, or disposed of”) in the scope of a risk evaluation.
  • The inclusion of all exposure pathways in the scope of a risk evaluation. EPA previously excluded exposure pathways covered under other EPA statutes in its risk evaluations for the first ten chemicals.
  • The removal of the definitions for “best available science” and “weight of the scientific evidence.” Though TSCA requires EPA to use the best available science and make decisions based on the weight of the scientific evidence at 15 U.S.C. 2625, EPA argues that the codification of these definitions inhibits the Agency’s ability to adapt to changing science.
  • The requirement that EPA make a single determination on whether the chemical presents an unreasonable risk. EPA initially made separate risk determinations for each condition of use in its risk evaluations for the first ten chemicals but later issued revised “whole substance” determinations.
  • The cessation of the consideration of “assumed” personal protective equipment (PPE) use when calculating exposure reduction due to PPE.
  • The addition of “overburdened communities” to the list of examples of potentially exposed or susceptible subpopulations.
  • A number of alterations to the process and requirements for manufacturer-requested risk evaluations.

The above changes would apply to all risk evaluations initiated on or after the date of the final rule.  For risk evaluations in progress on the date of the final rule, EPA expects to apply the changes “only to the extent practicable.”

The proposed clarification that EPA includes all conditions of use in the scope of a risk evaluation stems from the Ninth Circuit’s 2019 decision in Safer Chemicals, Healthy Families v. US EPA. In the case, petitioners successfully challenged EPA’s exclusion of “legacy uses and associated disposals”—such as the use and future disposal of asbestos in previously installed insulation—from the scope of risk evaluations. Several of the other proposed changes would codify existing EPA practices introduced in 2021, including the requirement that risk evaluations end with a single determination rather than use-by-use determinations.

EPA requests public comments on all aspects of the proposed rulemaking. Comments are due on December 14, 2023.