What are vinyl chloride and isobutylene? More about the chemicals released in Ohio train derailment

Taijuan Moorman
The Columbus Dispatch

Coverage of the East Palestine train derailment is being provided for free. Subscribe today to support local journalism and access all of our content online.

A train derailment in East Palestine carrying hazardous materials has been a cause of concern for residents in the area as government agencies continue to monitor the area.

Crews last week released toxic chemicals from derailed tanker cars near the Ohio-Pennsylvania border. Officials said the cars – part of a convoy that derailed in a fiery crash in East Palestine around 9 p.m. Feb. 3 as the 141-car Norfolk-Southern train was heading from Madison, Illinois, to Conway, Pennsylvania – had been in danger of exploding.

An evacuation order has since been lifted for the area.

How is the site being monitored?

The train included roughly 20 rail cars carrying hazardous materials, according to a letter the U.S. Environment Protection Agency sent Norfolk Southern.

Initially, vinyl chloride and later butyl acrylate were disclosed as released during the derailment. The EPA letter listed five materials known to have been released:

  • vinyl chloride.
  • butyl acrylate.
  • ethylhexyl acrylate.
  • ethylene glycol monobutyl ether.
  • isobutylene.

The EPA, which is investigating the release of hazardous substances, has noted the release of these chemicals into the air, surface soils and surface waters at the derailment site.

Materials have entered waterways near East Palestine, including Sulphur Run, Leslie Run, Bull Creek, North Fork Little Beaver Creek, Little Beaver Creek and the Ohio River, as well as storm drains, according to the agency.

East Palestine derailment: Read Norfolk Southern's remediation plan for the area

Columbus water supply: Drinking water safe from East Palestine train toxins

The EPA's community air monitoring continues to operate 24 hours a day as part of a re-occupancy plan. As of Sunday, 291 homes had been screened while 181 remained to be screened. The EPA claimed no detection of vinyl chloride or hydrogen chloride were identified for the completed screened homes.

What is vinyl chloride?

Vinyl chloride is a gas used to make polyvinyl chloride hard plastic resin in plastic products. It is found in products such as credit cards, furniture and car parts but is most notably used in PVC plastic piping, a common material in plumbing.

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

Vinyl chloride is more dangerous per part than ammonia and natural gas, according to federal regulations that dictate acceptable levels in the air.

Officials warned the controlled burn would send phosgene and hydrogen chloride into the air. Phosgene is a highly toxic, colorless gas with a strong odor that can cause vomiting and breathing trouble and was used as a weapon in World War I. Hydrogen chloride is a colorless to yellowish gas with a strong odor, and its primary effect on humans is skin, eye, nose and throat irritation.

Phosgene is considered safe at 0.1 parts per million during an eight-hour exposure or 0.2 ppm for a 15-minute exposure. The eight-hour exposure threshold would have to be even lower when measuring inside people's homes, where residents often spend more than eight consecutive hours. Hydrogen chloride is considered safe at 5 ppm for an eight-hour exposure.

What is butyl acrylate?

Found in one train car, butyl acrylate is a clear colorless liquid with a sharp, distinct smell less dense than water, which can form a surface slick on water, according to the National Library of Medicine. The chemical is used for making paints, coatings, caulks, sealants and adhesives.

The chemical found on the train car has been completely lost due to spill and fire, according to a list of affected train cars posted by Norfolk Southern.

What is isobutylene?

One train car contained isobutylene , a gas used in antioxidants – including food, packaging, supplements and plastics – butyl rubber and in the production of high-octane plane fuel. The chemical, which is heavier than air, is shipped as a liquefied gas under its own vapor pressure, which can cause frostbite and easily ignite. Its container may rupture violently and rocket under prolonged exposure to fire or heat.

Inhalation of moderate concentrations of isobutylene can cause dizziness, drowsiness and unconsciousness, while contact with the eyes or skin may cause irritation.

The train car shows no signs of a breach.

What is ethylhexyl acrylate?

One car contained ethylhexyl acrylate , a clear colorless liquid with a pleasant odor and vapors heavier than air. The chemical is used in making water-based paints, coating materials, adhesives, printing inks and plastics.

Inhalation and ingestion of concentrated ethylhexyl acrylate vapor can cause drowsiness and convulsions, while its liquid form can cause irritation of the eyes and may irritate the skin on prolonged exposure.

As of Sunday, the amount of ethylhexyl acrylate in the train car is still pending.

What is ethylene glycol monobutyl ether?

One car contained ethylene glycol monobutyl ether , which is a colorless liquid with a mild smell. The chemical is used in glass and leather cleaners and as a solvent in paints, coatings, inks and household cleaners. Ethylene glycol monobutyl ether irritates the skin and eyes and may be toxic if ingested. Contact and ingestion can cause headache, nausea, vomiting and dizziness. Occupational exposure can be high in silk screen printing.

The status of the car is currently unknown.

Reporting from the Associated Press is included in this story.