By Denise Chow and Kenzi Abou-Sabe —
NBC News
The toxic substances that were spilled and then burned, according to authorities, to prevent an explosion near the town of East Palestine (Ohio) by the derailment of a train on February 3 have names that are reminiscent of chemistry classes in the school: vinyl chloride, butyl acrylate and isobutylene.
Scientists are well aware of these names, as well as the environmental and health damage they can cause – from eye and skin irritation to respiratory distress and cancer – raising great concern about post-accident contamination.
The burning of these substances after the disaster is complicating an already tense situation that has sparked fears of harm to the health of citizens beyond this area of eastern Ohio.
Emergency workers assess risks in East Palestine, Ohio, on February 7.AP
The threat from these chemicals varies.
Residents of East Palestine have been told it is safe to return home, but many remain uncertain about continued exposure in air, water, and soil, even at low levels.
Five toxic chemicals have been identified in the area:
Vinyl Chloride:
This known carcinogen is a colorless, flammable gas used to produce polyvinyl chloride (PVC) plastic for electronic, medical, and construction packaging and products.
Symptoms of poisoning include drowsiness, disorientation, numbness and tingling in the extremities, and nausea, according to the Centers for Disease Control and Prevention (CDC).
The chemical can also irritate the eyes and skin.
Butyl Acrylate:
A colorless liquid with a strong, fruity odor that is commonly used to make various plastics, polymers, coatings, and resins.
According to the CDC, exposure to this chemical can cause eye and skin irritation, rashes, and breathing difficulties.
Isobutylene:
A colorless gas used to make plastics, packaging materials, and resins.
Exposure can cause symptoms such as dizziness and headache, but a cargo manifest provided to the Environmental Protection Agency (EPA) indicates that Norfolk Southern, the company that operated the train, did not observe "any signs of infraction” in the wagon that transported this chemical substance.
Ethylene glycol and ethylhexyl acrylate:
the latter is a colorless liquid used to produce plastics and polymers.
Ethylene glycol is a synthetic compound used in inks, paints, hydraulic brake fluids, and antifreeze.
Both can cause skin and eye irritation, as well as sore throat and nausea with exposure to high concentrations.
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More than two weeks after the 150-car freight train derailed, experts say it's unclear whether state and federal authorities are doing enough to assess the immediate and long-term impact these chemicals could have on health. human and the environment.
"There's been a lot of discussion about testing, safety and follow-up science, but there really isn't a coherent explanation about what they did, why they did it and what they're doing now," said Andrew Whelton, a professor of environmental engineering. and ecology at Purdue University.
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Whelton said he is especially concerned about harmful pollutants that may have been created by the derailment and fire.
These are compounds known as dioxins, different from the toxic substances initially discharged, but which are produced when products such as vinyl chloride are burned.
Although the Environmental Protection Agency has stated that it will continue to test and monitor East Palestine's air, water and soil, authorities have not specified whether the sampling will include by-products such as dioxins.
“They're heavy compounds that stick to things,” Whelton explains, “dioxins typically stick to particles that are created during burning and can then be deposited on people's property or into their homes.
And they can be quite toxic if ingested and inhaled."
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Dioxins are long-lived compounds that do not break down easily.
In some cases, Whelton says, they can be present in homes or other settings for decades.
Of the chemicals identified at the derailment site, vinyl chloride has been the main focus of attention.
According to the CDC, exposure to high doses can increase the risk of liver damage or liver cancer, but long-term exposure to low levels is also believed to have detrimental health consequences.
Vinyl chloride is a volatile compound that can exist in both liquid and gas forms.
This means it can seep into the soil and contaminate groundwater, but, especially at high temperatures, it can also contaminate the air, according to Juliane Beier, a University of Pittsburgh hepatologist who has studied the effects of vinyl chloride on animals.
A black column rises over East Palestine after the controlled detonation of part of the derailed trains on February 6. Gene J. Puskar / AP
"Vinyl chloride is very volatile, so in homes or other closed spaces it is released from water at room temperature, or especially when it is heated, when showering, cooking, etc.," Beier explained.
The EPA said it began testing air quality in the East Palestine area within 24 hours of the derailment and is also helping to monitor air quality as part of a voluntary program that includes more than 550 households. .
So far, the agency has reported that no vinyl chloride or hydrogen chloride has been detected above levels of concern.
But Mo Osman, who runs Summit Environmental Technologies, a lab that Columbiana County, Ohio, has contracted to test its water samples, said it can take time for contaminants to seep into groundwater reservoirs.
“If a well is safe right now, we don't know what the quality of that water will be a week, a month or two months from now,” he said, “it takes time for contamination to potentially travel from the contamination source to the well. individual, and it is very important to continue taking samples with a certain frequency”.
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Vinyl chloride isn't the only chemical that authorities are controlling, either.
EPA officials said butyl acrylate was detected during sampling of the Ohio River at concentrations below 3 parts per billion.
The agency said in a February 16 statement that it is “well below the 560 parts per billion that the CDC considers dangerous.”
They added that no vinyl chloride has been detected in the river at that time.
Last week, EPA Administrator Michael Regan said they are testing for all volatile organic chemicals and will continue to monitor air and water quality in the region.
The agency also announced that it would require Norfolk Southern to pay for cleanup efforts—which include identifying and cleaning up contaminated soil and water—reimburse EPA costs and participate in public meetings at the EPA's request.
Denise Chow reported from New York and Kenzi Abou-Sabe from Eastern Palestine.