Toxic gases connected to Ohio train derailment cause concern

Days after crews released and burned toxic chemicals transported by a wrecked train in Ohio, residents remain concerned about the toxic substances that could be lingering in their evacuated neighborhoods.

Vinyl chloride was slowly released into the air Monday from five of those cars before crews ignited it to get rid of the highly flammable, toxic chemicals in a controlled environment, creating a dark plume of smoke.

Residents in the immediate area there and nearby in Pennsylvania were evacuated beforehand because of health risks from the fumes and can't yet return Wednesday, as the impact of burning vinyl chloride is a concern.

WHAT IS VINYL CHLORIDE? The gas is used to make the polyvinyl chloride hard plastic resin in plastic products.

IS IT DANGEROUS? Vinyl chloride is associated with increased risk of liver cancer and other cancers, according to the federal government's National Cancer Institute.

The effect was studied in PVC pipe makers, who breathed in vinyl chloride and developed rare liver cancers, said Ruth Lunn, who studies carcinogens at the National Institute of Environmental Health Sciences.

Vinyl chloride is dozens of times less toxic per molecule than the U.S.-banned insecticide DDT but more dangerous per part than ammonia and natural gas, according to federal regulations that dictate acceptable levels in the air.

WHAT HAPPENS WHEN IT BURNS? Officials warned the controlled burn would send phosgene and hydrogen chloride into the air.

Hydrogen chloride is a colorless to yellowish gas with a strong odor and its primarily effect on humans is skin, eye, nose and throat irritation.

"Vinyl chloride is bad, dioxins are worse as carcinogens and that comes from burning," Donahue said.

Dr. Lynn Goldman, dean of George Washington University's School of Public Health, agrees this is a possible risk, but is more concerned about uncombusted vinyl chloride vapors that could be lurking in the immediate vicinity.

"Until there has been a thorough assessment, the soot as well as any other materials should in my opinion be treated as contaminated by vinyl chloride and/or dioxins or other contaminants until proven otherwise," she said.