On July 24, the U.S. Environmental Protection Agency (EPA) proposed to designate five chemicals as high-priority substances for risk evaluation under the Toxic Substances Control Act (TSCA). The agency
first announced the process of prioritizing these five chemicals in December 2023. The five chemical substances are:
- Vinyl Chloride (CASRN 75-01-4)
- Acetaldehyde (CASRN 75-07-0)
- Acrylonitrile (CASRN 107-13-1)
- Benzenamine (CASRN 62-53-3)
- 4,4’-methylene bis(2-chloroaniline) (MBOCA) (CASRN 101-14-4).
All five chemicals were selected from the 2014 TSCA Work Plan, which is a list of chemicals identified by the EPA for further assessment based on their hazards and potential for exposure.
In proposing these five chemicals for risk evaluation, the EPA considered the chemicals’ conditions of use (COU) and production volume or changes in COU and production volume over time, impacts to potentially exposed or susceptible subpopulations, including children and workers, and the chemicals’ potential hazards and exposures. The EPA also considered criteria such as the chemicals' bioaccumulation and environmental persistence and whether the chemical is stored near significant sources of drinking water.
The EPA’s proposed designations are not themselves a finding of risk. If the EPA finalizes these designations, the agency will initiate risk evaluations to determine whether these chemicals present an unreasonable risk to human health or the environment under the TSCA COU, which the agency must complete within three-and-a-half years. If, at the end of the risk evaluation process, the EPA determines that a chemical presents an unreasonable risk to health or the environment, the agency must begin the risk management process to take action to eliminate risk.
EPA will accept public comments on the proposed designations for 90 days after publication via docket EPA-HQ-OPPT-2023-0601 at
Regulations.gov. Upon publication of the Federal Register notice, supporting documents will also be available.
