The U.S. Environmental Protection Agency (EPA) is conducting a formal review of five highly toxic plastic chemicals, including vinyl chloride, the compound at the center of the infamous train wreck fire in East Palestine, Ohio. Such a move could lead to strict restrictions or bans on these substances.

Vinyl chloride is most commonly used in PVC pipe and packaging production, but is also carcinogenic and highly flammable. The federal government has considered restrictions on the substance for about 50 years, but industry has blocked most regulatory efforts, hidden the risks of the substances and has mobilized against new scrutiny.

Judith Enck, president of Beyond Plastics and a former administrator of the U.S. Environmental Protection Agency, said the move was "one of the most significant chemical review processes ever undertaken" by the agency.

"I commend the EPA," she added.

The federal government has designated vinyl chloride as a known carcinogen, which is also a neurotoxin linked to liver damage, permanent changes in bones and other serious health problems. The EPA is also reviewing acetaldehyde, aniline, acrylonitrile and MBOCA used in the production of plastics and rubber. All chemicals are known to be or may be carcinogens and have been linked to other health problems such as anemia, kidney damage and neurotoxicity.

The country's use of vinyl chloride drew intense scrutiny after dozens of cars on a Norfolk Southern train derailed and burned in eastern Palestine in February 2023. The fire broke out near a tanker carrying vinyl chloride and two days later officials conducted a controlled burn of the chemical as a precaution amid fears of a "major explosion".

When vinyl chloride is burned, it produces dioxins, a highly toxic and carcinogenic chemical that can remain in the environment for generations. Levels of dioxin found in East Palestine in the days after the wreck were hundreds of times higher than the exposure threshold the EPA found in 2010, above which it poses a cancer risk. Soil and food contamination are considered among the most common exposure pathways, and towering plumes from controlled burns have also transported dioxins to 16 states.

Vinyl chloride is transported by freight trains and is prone to accidents, and East Palestine is just one of a series of vinyl chloride accidents - and experts expect similar ones to follow. A recent report found that more than 3 million Americans live within 1 mile of railroad tracks that transport vinyl chloride.

The Ethylene Institute, which represents producers of vinyl chloride and polyvinyl chloride, downplayed the risk and called the reports a "publicity stunt."

EPA's announcement ends a yearlong effort to gather input from industry, public health advocates, labor and others involved in the use of these substances, as required by the Toxic Substances Control Act (TSCA). The law covers the use of these substances in the country. Toxic chemicals.

It will collect more information over the next three months and then determine whether to list the chemicals as high-priority substances under TSCA. This will trigger a formal study to determine whether vinyl chloride poses an unreasonable risk to human health or the environment.

That review could take three years, after which the EPA will develop new rules. But the action faces an uncertain future — incoming Trump allies have said they will cancel any proposed regulations that have not yet been finalized.

Industry opposition to PVC restrictions is expected to be strong, in part because the substance is used in medical equipment, vinyl siding on buildings, drinking water pipes, electrical wiring, shower curtains and household items such as raincoats — and has been touted by industry groups is prevalent in statements regarding EPA announcements.

"[It]provides a welcome opportunity to share our expertise in the many indispensable uses of this highly regulated material," the Vinyl Institute wrote.