Toxic chemicals

The U.S. Environmental Protection Agency (EPA) proposed to designate five chemicals as High-Priority Substances for risk evaluation under the nation’s chemical safety law, the Toxic Substances Control Act (TSCA). If EPA finalizes these designations as proposed, the agency would immediately move forward with the risk evaluation process. 

The five chemical substances EPA is proposing to designate as High-Priority Substances are:

• Vinyl Chloride (CASRN 75-01-4),

• Acetaldehyde (CASRN 75-07-0),

• Acrylonitrile (CASRN 107-13-1),

• Benzenamine (CASRN 62-53-3), and

• 4,4’-methylene bis(2-chloroaniline) (MBOCA) (CASRN 101-14-4).

“Studying the safety of these harmful chemicals — all five of which have been linked to cancer and are used to make plastic – would help lead to critical public health and environmental protections in communities across the country and would ensure that the public has access to more data on these chemicals sooner,”  says Assistant Administrator for the Office of Chemical Safety and Pollution Prevention Michal Freedhoff. 

Chemicals Proposed as High-Priority Substances for Risk Evaluation

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. In proposing these five chemical substances as High-Priority Substances for risk evaluation, EPA had to consider the chemicals’ conditions of use and production volume or changes in conditions of use and production volume over time, impacts to potentially exposed or susceptible subpopulations including children and workers, and the chemicals’ potential hazards and exposures. EPA also considered more specific criteria such as the chemicals' bioaccumulation and environmental persistence and whether the chemical is stored near significant sources of drinking water. 

Vinyl chloride is used primarily in the manufacturing and processing of plastic materials such as polyvinyl chloride (PVC), plastic resins, and other chemicals. Many of these materials are used for pipes and insulating materials. This chemical was also involved in the Norfolk Southern train derailment in East Palestine, Ohio. Vinyl chloride is a known human carcinogen and can cause liver, brain, and lung cancer in exposed workers. Short-term exposure to vinyl chloride can also result in other health effects such as dizziness, nausea, and eye and skin irritation. Vinyl chloride exposure can also damage genetic material in cells, which can lead to numerous adverse health effects. In the 1970s, the White House Council on Environmental Quality and EPA officials raised serious concerns about the health impacts of vinyl chloride as an example when the Nixon Administration asked Congress to write a law to ensure chemicals were made and used safely, which led to passage of the “original” TSCA in 1976.

Acetaldehyde is used primarily in the manufacturing and processing of adhesives, petrochemicals, plastic and other chemicals, as well as intermediates for products such as packaging and construction materials. Acetaldehyde is a probable human carcinogen. Specifically, animal studies have shown that exposure to acetaldehyde can result in the formation of nasal and laryngeal tumors. Short-term exposure can also result in health effects such as irritation of the respiratory system and reduced heart function. Data further shows that acetaldehyde exposure can damage genetic material in cells, potentially leading to numerous adverse health effects. 

Acrylonitrile is used primarily in the manufacturing and processing of plastic materials, paints, petrochemicals, and other chemicals. Acrylonitrile is a probable human carcinogen and can cause lung and brain cancer in exposed workers. Short-term exposure to acrylonitrile can also result in health effects such as eye, skin, and respiratory irritation. Long-term exposure can result in reproductive effects such as reduced sperm count and developmental effects such as slowed fetal growth.

Benzenamine is used in the manufacturing and processing of dyes and pigments, petrochemicals, plastics, resins, and other chemicals. Benzenamine is a probable human carcinogen and can cause bladder tumors and pancreatic cancer in workers. Long-term exposure to benzenamine can result in a range of adverse health effects such as difficulty in breathing, tumor growth in the spleen, and possible reductions in fetal viability.

MBOCA is used in the manufacturing and processing of rubbers, plastics, resins, and other chemicals. MBOCA is a probable human carcinogen. Specifically, animal studies have shown that exposure to MBOCA can cause liver and urinary bladder cancer. Short-term exposure to MBOCA can result in eye and skin irritation. Data further demonstrates that MBOCA exposure can damage genetic material in cells, potentially leading to numerous adverse health effects.