News & Insights


On May 3, 2024, the EPA published a final rule detailing the processes by which the EPA will evaluate the risks certain chemicals pose to human health and to the environment under the Toxic Substances Control Act (TSCA). The TSCA authorizes the EPA to maintain a database of all chemical substances manufactured in or imported to the United States, excluding food, drugs, cosmetics and pesticides. The Act also authorizes the EPA to require testing of certain compounds, notification prior to the production of a new chemical, and reporting related to manufacture, use, and distribution of chemicals. Producers and others introducing a chemical substance into commerce can be required to notify the EPA if they find the chemical poses a risk to health or the environment.

A 2016 amendment to TSCA required the EPA to establish a procedural framework rule on the process for conducting chemical risk evaluations. Chemical risk evaluations involve collecting, integrating, and assessing data related to chemicals regulated under TSCA to determine whether the data show the corresponding chemicals pose threats to human health and the environment. In 2017, the EPA released and implemented the first risk evaluation rule.

One effect of the new rule is to expand the conditions of use considered as EPA evaluates the risks related to a chemical. Under the TSCA, a condition of use is “the circumstances, as determined by the Administrator, under which a chemical substance is intended, known, or reasonably foreseen to be manufactured, processed, distributed in commerce, used or disposed of.” The new rule requires that every condition of use be considered in the risk evaluation process. Critics believe this may promote inefficiency, compared to focusing efforts on conditions of use projected to have the greatest effect on health or environment. The EPA says the rule allows professional judgment to direct resources to their best uses.

The rule also names considerations to be incorporated into its analysis corresponding to specific ways in which a chemical may contact individuals or the environment. Occupational exposure is to be considered with the assumption that no steps are taken to reduce the impact of the chemical on an individual. The TSCA requires the EPA to consider heightened risks to “potentially exposed or susceptible subpopulations.” The new rule will add “overburdened populations” to the list of susceptible subpopulations. Aggregate exposure and cumulative risk concerns do not appear to be dealt with differently in the new rule.

Additionally, TSCA requires the EPA base its risk evaluations on the “best available science” and the “weight of scientific evidence.” These phrases were previously defined in the regulatory text. The new rule eliminates the definitions. The EPA explains that defining the phrases may limit the implementation of new or novel scientific approaches in the future. Eliminating the definition ensures the EPA is free to carry out the aims contemplated by the law using the best methods available. Critics believe this gives the EPA greater discretion to use unsound methods in evaluating chemicals’ risks.

Some commentors believe aspects of the new rule may be used by litigants to prompt the Courts to further define the relation of courts and regulatory agencies in interpreting regulatory responsibilities granted by statute. The Supreme Court will soon consider challenges to the Chevron doctrine in Loper Bright Enterprises v. Raimondo and Relentless Inc. v. Department of Commerce. The Court has also recently recognized the major questions doctrine in West Virginia v. EPA. Disputes regarding the new TSCA risk evaluation rule may have additional consequences regarding regulatory authority by executive agencies.