Update: East Palestine train derailment involved older tank equipment

Nov 26, 2023

Key safety equipment on tank cars carrying cancer-causing toxic chemicals in last month's East Palestine, Ohio, train derailment may have been compromised, "possibly degrading" their ability to protect the public from catastrophic tank failure under fire conditions, according to an investigative update from the National Transportation Safety Board.

Despite concerns about the equipment, so far, there is no indication the cars carrying vinyl chloride were breached, NTSB spokesman Keith Holloway said, but the investigation remains ongoing.

The Norfolk Southern train derailed Feb. 3 after a railcar's wheel bearing overheated and a subsequent fire broke out. Worries about increased temperature in a vinyl chloride tank car and possible explosion led the company to undertake a "controlled release" of the chemicals in the tank cars. That required thousands of the rural town's residents to evacuate for days, amid concerns of air and water quality.

Norfolk Southern did not immediately reply to a request for comment.

The environmental toll: East Palestine train derailment killed more than 43,000 fish and animals, officials say

NTSB investigators found that three of the five vinyl chloride carrying tank cars were equipped with aluminum protective housings manufactured in the 1990s. Investigators were "concerned" to learn that these protective covers "melted or were consumed" when the pressure relief devices (PRDs) housed beneath them vented burning gas to relieve tank pressure.

"Preliminary examination suggests that melted aluminum may have dripped into some PRDs, possibly degrading their performance," the NTSB said in their update. The safety agency is now trying to determine the numbers of tank cars in operation that are still equipped with such housings, which are crucial to protecting pressure relief devices from damage.

The pressure relief devices are supposed to help regulate internal tank pressure by releasing small amounts of material and closing back up once conditions return to normal.

Holloway said investigators are still gathering information about when the industry transitioned to steel for such protective housings but early information indicates it was in early 2000.

"NTSB investigators of course will review the history of the requirements to see if the current status is sufficient for the industry," Holloway said in an email. He said the agency can make recommendations to review standards, procedures and guidelines, if necessary.

Also Thursday, the U.S. Department of Transportation's Pipeline and Hazardous Materials Safety Administration (PHMSA) issued a safety advisory notice urging "all hazmat tank car owners and offerors to survey their fleets for any tank cars currently equipped with aluminum protective housing and consider replacing this equipment with carbon steel housings, which we understand to be current industry practice."

In the safety notice, the agency's associate administrator, William Schoonover, said that PHMSA and the Federal Railway Administration could take more action in the future if the investigation shows that the destroyed covers "significantly contributed to improper functioning of the pressure relief devices."

In other accidents, investigators have found that carbon steel protective housing covers survive fires and prolonged "pool fires," where fuel is evaporating, likely because it has a higher melting point than aluminum.

Follow Tami Abdollah on Twitter at @latams or email her at tami(at)usatoday.com