EAST PALESTINE, Ohio — Authorities plan to conduct a controlled release of toxic chemicals on Monday afternoon, three days after several train cars carrying hazardous materials derailed in northeastern Ohio.

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Update 5:23 p.m. EST Feb. 6: A massive explosion occurred at the scene of the train derailment in East Palestine following a chemical release, according to WPXI.

The controlled explosion happened as toxic gases were released from one of the cars, according to WPXI.

- Jessica Goodman, Cox Media Group National Content Desk

Original story: Gov. Mike DeWine said officials are concerned that the train cars could create a “potentially catastrophic” explosion. Earlier, in a statement issued after state officials ordered the evacuation of residents on Sunday night, authorities said that “a drastic temperature change has taken place in a rail car, and there is now the potential of a catastrophic tanker failure which could cause an explosion with the potential of deadly shrapnel traveling up to a mile.”

“The vinyl chloride contents of five rail cars are currently unstable and could potentially explode, causing deadly disbursement of shrapnel and toxic fumes,” DeWine said at a news conference on Monday. “To alleviate the risk of this shrapnel, Norfolk Southern railroad is planning a controlled release of the vinyl chloride at approximately 3:30 p.m.”

Law enforcement officials are going door-to-door in the area surrounding the scene of the derailment to ensure that residents leave before the controlled chemical release. The governor warned that people in the immediate area faced “a grave danger of death if they are still in that area.” Others in the evacuation area “are at risk of severe injury … including skin burns and serious lung damage,” he said.

Scott Deutsch, the regional manager of hazardous materials for Norfolk Southern Corporation, said at a news conference Monday that authorities decided to perform a controlled release of chemicals “so that we control (these tank cars) that we have concerns with.” Officials will create a 2 1/2- to 3-inch hole in the problem train cars, allowing the chemicals to drain into a trench where they will then be set alight, he said.

“It’s better for everyone, for us to do it that way,” Deutsch said. “If we don’t do that, the car could continue to polymerize, and the entire car will break apart. We can’t control where that goes.”

On Sunday, officials said that more than 500 people in the area declined to leave their homes before state officials urged evacuations. DeWine said authorities helped get nearly 100 more people evacuated that night.

Authorities have been monitoring the situation since a train traveling from Madison, Illinois, to Conway, Pennsylvania, derailed in East Palestine. Officials with the National Transportation Safety Board said the train included 141 load cars, nine empty cars and three locomotives. About 50 of the cars were involved in the derailment, 10 of which contained hazardous materials. Five of those cars contained vinyl chloride, a highly flammable gas mostly used primarily to make polyvinyl chloride, better known as PVC. The substance is linked to an increased risk of several cancers, according to the National Institutes of Health.

Friday’s derailment sparked a fire and blocked the two main tracks, NTSB board member Michael Graham said Saturday. The agency is the lead federal investigator into the incident.

It was not immediately clear what caused the derailment. Authorities are investigating. Graham said the NTSB will likely release a preliminary report in four to six weeks.

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