The Ohio Train Derailment and its Toxic Aftermath

April 21, 2023

A discussion about plastics, vinyl chloride, and the chemical fallout of the derailment in East Palestine, Ohio.

The nation was shocked when a freight train carrying hazardous chemicals derailed in the village of East Palestine, Ohio, in February. The accident led to a massive chemical spill and triggered a national conversation about train safety and vinyl chloride, a highly flammable, colorless gas used to make polyvinyl chloride, known as PVC.

Operated by Norfolk Southern Railway, the 2-mile-long train was near the Pennsylvania border when dozens of cars derailed and caught on fire, sending plumes of black smoke billowing into the air. Roughly half of the village's 4,700 residents were ordered to evacuate.

The derailment produced one the country's largest chemical spills in years, and the full extent of the damage is yet unknown. However, the accident has put an intense spotlight on the safety of freight trains and the toxic cargo they carry.

The Graduate Center spoke to faculty — chemists and a public health scholar — to discuss the chemicals that make plastics and the dangers they pose as they travel by freight.

What is Vinyl Chloride?

Vinyl chloride is a precursor used in the production of PVC, a type of plastic found in a wide array of everyday products. The EPA has classified vinyl chloride as a known human carcinogen. The primary route of exposure to vinyl chloride gas is inhalation, which can cause respiratory irritation, headaches, disorientation, loss of consciousness and even, at very high levels of exposure, death.

PVC is used in many building materials, including pipes and window sidings, wire coatings, electronics, medical supplies, flooring, toys, kitchenware, and countless other household items. "If you buy a new toothbrush, it's going to have clear plastic, what they call a blister pack, and that clear plastic is frequently PVC," said Professor Alan Lyons, (GC/College of Staten Island, Chemistry, Nanoscience), a polymer chemist. "It's one of the top mass-produced plastics in the world."

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Vinyl chloride itself is a monomer, a molecule that forms the basic unit of polymers. These may be natural biopolymers — wood, silk, rubber, starch, and even DNA — or synthetic polymers, used to make plastics like silicone, polyethylene, nylon, and PVC.

"It's called a monomer because these are small molecules that can be made to react together to make a very long chain, and they keep repeating in that chain to make a polymer," Lyons said.

Heat triggers chemical reactions

As the cars burned, fears of a possible explosion led to a controlled burn of vinyl chloride gas in five train cars. When burned, vinyl chloride decomposes into gases including phosgene and hydrogen chloride.

"Because the vinyl chloride molecule contains hydrogen and chlorine, when it's heated, it's going to decompose," Lyons explained, "and one of those decomposition products is going to be hydrochloric acid," a corrosive acid that can cause eye, nose, and respiratory tract irritation.

Phosgene, described as "extremely toxic" by the National Institutes of Health, can cause severe damage to the lungs and nervous system. The gas is so toxic that it was used as a chemical warfare agent, responsible for the vast majority of chemical weapons fatalities during World War I.

In addition, dioxins were found in soil at the site. But, officials say, the highly toxic compounds were found in small amounts. The EPA has deemed dioxins to be probable carcinogens, except for one — 2,3,7,8-tetrachlorodibenzo-p-dioxin, identified as a known carcinogen, and present in the soil samples.

Dioxins are created through combustion and, with few exceptions, are not formed in nature, said Professor Jin Shin (GC/Medgar Evers College, Earth and Environmental Sciences). "Why? Because dioxins are formed in very, very high-temperature conditions," the chemist said, as in municipal incineration, wildfires, and volcanic eruptions.

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But these chemicals weren't the only hazardous materials spilled after the train went off the tracks; in fact, the 18,000-ton train was also carrying flammable butyl acrylate, ethylhexyl acrylate, isobutylene, and benzene — all used to make plastics.

The spilled chemicals contaminated nearby streams and creeks, where thousands of fish died in the immediate aftermath of the accident. By late February, the Ohio Department of Natural Resources estimated, more than 38,000 minnows and 5,500 other species, including other fish and macroinvertebrates, perished as a result of the derailment.

Shin thinks it was a combination of different chemicals that led to the die-off, and doubts the cause was vinyl chloride alone. "It quickly evaporates in water, like carbon dioxide in a soda can," he said. In any case, the potential repercussions of the derailment on the health of residents and the local ecosystem are serious, Shin said. At least a year of air and water quality monitoring is needed around the contaminated site, he said.

The transport of large quantities of hazardous materials by rail requires stricter safety regulations, Shin says. And the trains that hold these hazardous chemicals need upgraded designs with improved alarm systems, temperature, and pressure sensors, he said.

Weeks after the accident, the National Transportation Safety Board reported that an overheated wheel bearing caused the train to derail. Railside detectors failed to warn train operators of the problem until it was too late. Aluminum parts, melted in the fire, also damaged pressure-relief valves inside the tanks, the NTSB said.

Possible impacts on human health

Exposure to vinyl chloride has been linked to increased risk of a rare form of liver cancer, called hepatic angiosarcoma, in addition to primary liver cancer, brain and lung cancers, lymphoma, and leukemia, according to the NIH.

The EPA is currently conducting cleanup at the derailment site. The work includes removal of contaminated soil and wastewater, air and water monitoring, and well water and soil sampling.

Federal, state, and local agencies have stepped in to provide East Palestine residents with screenings and direct health care in the wake of the accident; the Ohio Department of Health has offered testing and physical exams to first responders who were on the scene.

In a recent New York Times op-ed, Distinguished Professor Gerald Markowitz (GC/John Jay College, History) called for an outright ban of vinyl chloride and a phasing out of PVC plastic. Until then, he and co-authors wrote, communities like East Palestine would be exposed to "ticking time bombs of cancer."

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"Millions of pounds of hazardous chemicals are transported by rail every year," said Markowitz, co-author of Deceit and Denial: The Deadly Politics of Industrial Pollution. "Over the past decade, there have been about 500 accidents where dangerous chemicals have either spilled or leaked from trains that were in transit or waiting to be moved," he said, but this figure is hard to verify because these spills and accidents are self-reported.

Americans are also at risk due to billions of pounds of chemicals released from industrial plants all over the U.S., Markowitz said, and they’re often located in economically disadvantaged areas.

In this country, chemicals are generally considered safe until they’re proven otherwise, Markowitz said. "They are innocent until proven guilty," he said. "But for chemicals, we need to take a public health approach and adopt the precautionary principle. We need to have a system in place where chemical companies and the government prove the safety of chemicals before they are put into widespread use."

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