Roughly two weeks after a train carrying toxic and combustible materials derailed just outside a small town near the Ohio-Pennsylvania border, filling the sky with black smoke, questions are raging about the health and environmental impact of the disaster.
The derailment of the train operated by Norfolk Southern on February 3 near East Palestine, Ohio, sparked a massive fire that sent fumes from several toxic chemicals into the air. To reduce the risk of an explosion, officials released at least one chemical from five derailed tankers on February 6. (About 50 of the train’s 150 cars were involved in the accident.) Some of the substances were diverted to a designated ditch where they were burned, the Environmental Protection Agency wrote in a Feb. 10 letter to the train company.
But even now, scientists are still struggling to understand the short- and long-term health effects of the chemicals on residents of the city of 5,000 and the surrounding region. Many reports have focused on vinyl chloride — a clear, flammable gas used to make polyvinyl chloride (PVC) plastic, which is used in everything from plumbing to packaging to flooring. Scientists have known for decades that high doses of vinyl chloride can cause liver cancer. And even lower doses, especially over long periods of time, can be dangerous to a person’s health. People can be exposed to the chemical as vapor or by drinking contaminated water.
“We’re looking at concentrations that are currently considered safe, and in our studies we’ve observed that these low doses can exacerbate underlying diseases — we’re talking about liver disease,” says Juliane Beier, a hepatologist at the University of Pittsburgh who studies vinyl chloride exposure in animals.
It’s not clear how much of a risk vinyl chloride could pose at this point, after much of what was on the train burned down. Of course, igniting a hazardous material is far from an ideal disposal method. The problem is that by the time a car full of vinyl chloride does derail, there are usually no better options available. (Investigators with the National Transportation Safety Board continue to seek answers as to what caused the derailment in the first place.)
“In environmental risk assessment, we have to make a lot of decisions that we don’t want to make,” says Kim Garrett, an environmental toxicologist at Northeastern University.
In this case, that meant burning the vinyl chloride, rather than releasing the chemical into the environment and waiting to see if one or more of the train cars might explode.
Garrett says the main risk of burning vinyl chloride, whether controlled or not, is the production of two nasty chemicals: phosgene, which both Germany and the Allies used to kill trenches full of soldiers during WWI, and hydrogen chloride, which , can turn into hydrochloric acid – a key component of stomach acid – in the lungs when inhaled. However, by intentionally burning off the vinyl chloride in this case, responders could evacuate residents long enough for these two short-lived chemicals to degrade or otherwise change form rather than risk an unpredictable explosion with people nearby.
Vinyl chloride wasn’t the only chemical on the train: A partial inventory shared by the EPA offers more insight into some of the other materials it carried. And the agency’s letter dated February 10 states, “Cars containing vinyl chloride, butyl acrylate, ethylhexyl acrylate and ethylene glycol monobutyl ether have been and are known to have been released into the air, surface soil and surface water.” All three chemicals are known irritants for humans, although scientists have no evidence that they can cause cancer.
But these documents raise as many questions as they answer, says Garrett. “I can become concerned about a chemical when I see it written down and know how it behaves in a laboratory setting. But I don’t know how every chemical in the environment or every chemical reacts with each other, how they react in large quantities,” she says. “There’s a lot of toxicological nuance here, and I know that’s not the answer the public deserves, that it needs.”
In response to a request for comment from Scientific American, a Norfolk Southern representative referred to the company’s Feb. 15 statement, as well as statements from state and federal government agencies about drinking water testing and house inspections.
To give the public the answers it needs, scientists need to better determine what’s happening on the ground — and that means a lot of surveillance, experts say. EPA staff have been on the scene since the day after the derailment, and the agency is publicly sharing aerial surveillance data. Experts are also testing well-tapped, locally sourced drinking water and are encouraging residents to rely on bottled water until this work is complete.
“Officials are testing the outside air and they’re not reporting any concerns, and that’s good news,” says Beier. However, she adds that testing should continue for at least a year — and longer if worrisome compounds emerge. “I think the air and the water, but above all the indoor air in closed rooms all around, should be monitored longer,” says Beier, “not just this one snapshot.”
According to Nesta Bortey-Sam, an environmental toxicologist at the University of Pittsburgh, located about 50 miles from the site of the derailment, it’s not yet clear if the EPA has screened the site for other chemicals of concern. These substances include dioxins, a type of pollutant known to accumulate in animals and humans over time. When people are exposed to high levels of dioxins, people can develop chloracne (an acne-like skin condition), liver problems, and elevated blood fat levels, which can increase their risk of heart disease and stroke, according to the Centers for Disease Control and Prevention.
“My recommendation is to broaden the scope and look at more chemicals because I think there’s a longer list than what’s currently being studied,” says Bortey-Sam.
Garrett says it’s important that independent groups, as well as the EPA and Norfolk Southern, monitor the situation. She also hopes residents will get together to do their own science, like mapping where people have headaches or see dead fish. Garrett notes that this type of work can help bring political power to residents after a chemical disaster.
But people living near the crash site may also need support to monitor their health, she adds. “In the region in general, rural healthcare has been a problem. hospitals close; People don’t have access to doctors like they used to,” says Garrett. “It’s definitely important in the region to make sure everyone has access to health care for any ailments and problems they notice.”