EPA plans to prioritize the following chemicals for risk evaluation under the Toxic Substances Control Act (TSCA):

• 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), and
• Vinyl Chloride (CASRN 75-01-4).

Going forward, EPA said it expects to initiate prioritization on five chemicals every year, which will create a sustainable and effective pace for risk evaluations. Prioritization is the first step under EPA’s authority to regulate existing chemicals currently on the market and in use – to evaluate whether health and environmental protections are needed.

If at the end of the risk evaluation process EPA determines that a chemical presents an unreasonable risk to health or the environment, the agency must immediately start the risk management process to take action to eliminate these unreasonable risks.

Acetaldehyde is primarily used in the manufacturing and processing of adhesives, petrochemicals, and other chemicals, as well as intermediates for products like packaging and construction materials. Exposure to acetaldehyde may result in a range of health effects such as irritation of the respiratory system. It is a probable human carcinogen.

Acrylonitrile is primarily used in the manufacturing and processing of plastic materials, paints, petrochemicals and other chemicals. Exposure to acrylonitrile may result in a range of health effects such as irritation of the respiratory system. It is a probable human carcinogen.

Benzenamine is used in the manufacturing and processing of dyes and pigments, petrochemicals, plastics, resins and other chemicals. Exposure to benzenamine may result in a range of health effects such as adverse effects on the blood, fetal development, and reproduction. Benzenamine is a probable human carcinogen.

MBOCA is used in the manufacturing and processing of rubbers, plastics, resins and other chemicals. It is a probable human carcinogen. There is also extensive data that demonstrate exposure to MBOCA may damage genetic material in cells, potentially leading to other adverse health effects, particularly when exposure occurs to infants and children.

Vinyl chloride is primarily used in the manufacturing and processing of plastic materials like polyvinyl chloride (PVC), plastic resins, and other chemicals, many of these materials are used for pipes, insulating materials, and consumer goods. This chemical was also involved in the Norfolk Southern train derailment in East Palestine, Ohio. Exposure to vinyl chloride may result in a range of health effects such as liver toxicity. It is also a known human carcinogen. In the 1970s, the White House Council on Environmental Quality and EPA officials raised serious concerns about the health impacts of vinyl chloride. These concerns were the impetus for Congress to write a law to ensure chemicals were made and used safely, which led to passage of the “original” TSCA in 1976.

All five chemicals were selected from the 2014 TSCA Work Plan, which is a list of chemicals identified by EPA for further assessment based on their hazards and potential for exposure.

EPA will accept public comments on these chemicals for 90 days after publication at the Regulations page under docket EPA-HQ-OPPT-2023-0601.