The U.S. Environmental Protection Agency (EPA) said on Thursday that it has instructed the operator of a freight train that derailed in East Palestine, Ohio, to test for dioxins.

Dioxins testing in East Palestine

Since the controlled release and burn of the chemical vinyl chloride days after the derailment that occurred on February 3, a chorus of academics, environmentalists and residents have been raising the alarm about potential dioxin contamination.

According to EPA administrator Michael Regan, the agency is directing the railroad to conduct testing for the pollutants based on concerns from the community. The EPA will oversee the testing and "direct the company to conduct immediate clean up if contaminants from the derailment are found at levels that jeopardize people's health," Regan said in a statement.

For more: Did dioxins spread after the Ohio train derailment?

Dioxins and their impact

Dioxins are called persistent organic pollutants (POPs), meaning they take a long time to break down once they are in the environment, according to the EPA website.

The pollutants are found throughout the world in the environment, and they accumulate in food chains, mainly in the fatty tissue of animals. It takes between 7 and 11 years for dioxins to start to break down in the body of a person or animal, according to the World Health Organization. And dioxins have been linked with cancer, developmental problems in children and reproductive issues and infertility in adults.

Pure dioxin looks like white crystalline needles. In the environment, however, it generally is dispersed and attached to soil and dust particles and is invisible to the eye.

Expert: Dioxins could spread beyond site of train derailment 

Some experts have been stressing that dioxin testing is urgently needed, suggesting that dioxins could have attached themselves to particles of dust in the air and eventually settled to the ground. That could mean contamination spread well beyond the site of the derailment on the east side of East Palestine, said Stephen Lester, science director for the Center for Health, Environment & Justice.

According to the Guardian, dioxins were among the pollutants that emanated from a dump site in the Love Canal community of Niagara Falls, New York, leading it in 1984 to be declared a Superfund site in need of long-term remediation. The community of Times Beach, Missouri, was eventually abandoned and declared a Superfund site after it sprayed its roads with dioxin-contaminated oil in an effort to control dust.

Residents have voiced fears that East Palestine will join those places as a toxic town. One woman said the EPA's order to test for dioxin offers an opportunity to ease those concerns, but added that she is doubtful the findings will be encouraging.

"I'm still scared to stay here for sure," said Tamara Lynn Freeze, who lives with her husband a few hundred yards from the derailment site.

Lester, whose center was born out of the Love Canal disaster, questioned why testing for dioxins hasn't been a higher priority.

"It's a Pandora's box," Lester said. "They'll find it and then they're going to have to address the risks."

(With input from agencies; Cover: A plume rises from a Norfolk Southern freight train that derailed in East Palestine, Ohio, U.S., February 4, 2023./ CFP)

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