Did dioxins spread in Ohio?
After a catastrophic 38car train derailment in East Palestine, Ohio, some officials are raising concerns about a type of toxic substance that tends to stay in the environment.
Last week, Sherrod Brown and J.D. Vance, the U.S. senators from Ohio, sent a letter to the state's environmental protection agency expressing concern that dioxins may have been released when some chemicals in the damaged railcars were deliberately burned for safety reasons. They joined residents of the small Midwestern town and environmentalists from around the U.S. calling for state and federal environmental agencies to test the soil around the site where the tanker cars tipped over.
A look at dioxins, their potential harms and whether they may have been created by burning the vinyl chloride on the Norfolk Southern train.
Highly toxic, persistent compounds
Dioxins refer to a group of toxic chemical compounds that can persist in the environment for long periods of time, according to the World Health Organization.
They are created through combustion and attach to dust particles, which is how they begin to circulate through an ecosystem.
Residents near the burn could have been exposed to dioxins in the air that landed on their skin or were breathed into their lungs, said Frederick Guengerich, a toxicologist at Vanderbilt University.
Skin exposure to high concentrations can cause what's known as chloracne — an intense skin inflammation, Guengerich said.
But the main pathway that dioxin gets into human bodies is not directly through something burning like the contents of the East Palestine tanker cars. It's through consumption of meat, dairy, fish and shellfish that have become contaminated. That contamination takes time.
“That's why it's important for the authorities to investigate this site now,” said Ted Schettler, a physician with a public health degree who directs the Science and Environmental Health Network, a coalition of environmental organizations.
Does burning vinyl chloride create dioxins?
Linda Birnbaum, a leading dioxins researcher, toxicologist and former director of the National Institute for Environmental Health Sciences, said that burning vinyl chloride does create dioxins. Other experts agreed the accident could have created them.
The “tremendous black plume” seen at East Palestine suggests the combustion process left lots of complex carbon compounds behind, said Murray McBride, a Cornell University soil and crop scientist.
McBride said it will be hard to say for sure whether these compounds were released until testing is done where the train cars derailed.
Which is likely why residents, politicians, environmentalists and public health professionals are all calling for state and federal environmental agencies to conduct testing at the derailment site.
Routes to the environment
There is already some level of dioxins in the environment — they can be created by certain industrial processes, or even by people burning trash in their backyards, McBride said.
Once they are released, dioxins can stick around in soil for decades. They can contaminate plants including crops. They accumulate up the food chain in oils and other fats.
In East Palestine, it's possible that soot particles from the plume carried dioxins onto nearby farms, where they could stick to the soil, McBride said.
“If you have grazing animals out there in the field, they will pick up some of the dioxins from soil particles,” he said. “And so some of that gets into their bodies, and then that accumulates in fat tissue.”