EPA Flags Vinyl Chloride and Four Other Chemicals for Risk Evaluation

Vinyl chloride is among five chemicals that EPA is proposing to designate as high-priority substances for risk evaluation under the Toxic Substances Control Act (TSCA). The agency describes prioritization as the first step toward regulating chemicals that are currently on the market and in use. If EPA finalizes these proposed designations, the agency will begin risk evaluations to determine whether the substances present unreasonable risk to human health or the environment. TSCA calls for EPA to publish final risk evaluations within three to three-and-a-half years of identifying chemicals as high priority for risk evaluation. The four other chemicals EPA is proposing to evaluate are acetaldehyde, acrylonitrile, benzenamine, and 4,4’-methylene bis(2-chloroaniline), or MBOCA.

Vinyl chloride was one of the hazardous substances on board the Norfolk Southern train that derailed in February 2023 near East Palestine, Ohio. In the U.S., vinyl chloride is used primarily by the plastics industry to produce polyvinyl chloride, or PVC. According to EPA, vinyl chloride is a known human carcinogen that can cause liver, brain, and lung cancers among exposed workers. The chemicals acetaldehyde, acrylonitrile, benzenamine, and MBOCA are also used to manufacture and process plastics as well as other materials, chemicals, and products, and the agency states that they are probable human carcinogens.

The publication of the proposed designations in the Federal Register today opens a 90-day public comment period during which EPA will accept feedback to inform the exposure and hazard assessments for these five chemicals. Also available in the docket on Regulations.gov are documents for each substance that outline the information, analysis, and basis that EPA used to support its proposed designations.

Further details can be found in EPA’s press release announcing the proposed high-priority substance designations. Interested individuals can learn about the process for submitting comments in the Federal Register. Comments close on Oct. 23.