Following a train derailment in East Palestine, Ohio, just over a month ago, authorities carried out a controlled release of the toxic vinyl chloride gas into the atmosphere to prevent a massive explosion. There are now concerns about air, soil and water pollution because of the derailment.

The Environmental Protection Agency said that about 20 rail cars carried hazardous materials when the train came off its tracks. While many officials have said the area is safe, residents remain wary of possible toxins that may remain.

What is Vinyl Chloride?

Vinyl chloride is a colorless gas that burns easily and evaporates quickly. It does not occur naturally in the environment. Instead, it must be produced industrially, according to the National Cancer Institute.

Vinyl chloride is primarily used to make polyvinyl chloride, or PVC. PVC is used to make a variety of plastic products, such as piping, wiring and packaging materials. It is all around us, we just typically don’t see it. And PVC piping is completely safe, since it doesn’t add vinyl chloride into drinking water.

How Vinyl Chloride Can Poison the Environment

Vinyl chloride isn’t meant to exist in the natural world in large quantities, but that doesn’t mean it’s stopped from reaching the environment completely.

Typically, vinyl chloride is only found in large amounts in and around the factories that produce it. Once it seeps into the environment, it is broken down by sunlight over the course of a few days into other chemicals, such as formaldehyde. If vinyl chloride gets into soil or surface water, most of it evaporates into the air quickly, according to the Ohio Department of Health.

However, that doesn’t mean the chemical is harmless — far from it. According to the National Cancer Institute, vinyl chloride is a carcinogen, and “is associated with an increased risk of a rare form of liver cancer, as well as primary liver cancer, brain and lung cancers, lymphoma, and leukemia.”

Those most often exposed to vinyl chloride are workers building vinyl products, making the risk for a wider population low. This changed with the train derailment in East Palestine though, as other toxic chemicals — such as butyl acrylate, ethylhexyl acrylate and ethylene glycol monobutyl ether — were released into the atmosphere, along with vinyl chloride.

The impact on the surrounding area has been immense. While it isn’t known how residents’ health has been changed, and while long-term effects will remain unknown, environments in central Ohio and beyond have been hit hard.

The train in East Palestine derailed on Feb. 3, 2023. Five days after the spill, over 3,500 fish in local waters had died. While vinyl chloride has since dissipated from the waters, it was the likely culprit for what killed the fish.

It’s also possible that vinyl chloride seeped into soil around East Palestine, which has the potential to poison wells in the area. While state and national officials have stressed that water is safe to use, it’s ultimately unclear what impacts the East Palestine train derailment may have down the line.