Controlled chemical release scheduled to prevent explosion in wake of Ohio train derailment

Three days after a 150-car train derailed in northeastern Ohio, and risked exploding due to chemicals on board, authorities have announced a planned chemical release.

Evacuations had already been underway over the weekend within a 1-mile radius of the crash in the village of East Palestine since the crash was reported at 8:55 p.m. Friday.

It's not clear what caused the train to derail, but since it did, the crash site has produced multiple small explosions after multiple cars believed to be transporting hazardous materials erupted in the derailment and continued to burn Sunday morning.

At least five of the derailed cars were said to be carrying a chemical of concern, vinyl chloride, which is highly flammable and is linked to increased risk of cancer, National Transportation Safety Board member Michael Graham said Sunday.

In a news conference Monday afternoon, Ohio Gov. Mike DeWine said: "The vinyl chloride contents of five rail cars are currently unstable and could potentially explode causing deadly disbursement of shrapnel and toxic fumes."

"To alleviate the risk of this shrapnel, Norfolk Southern Railway is planning a controlled release of the chemical at 3:30 p.m. The controlled release also has the potential to be deadly if inhaled," he said.

As a result, DeWine and Pennsylvania Gov. Josh Shapiro ordered an immediate evacuation of a 1-mile by 2-mile area surrounding East Palestine that includes parts of Ohio and Pennsylvania.

DeWine shared a model of the area surrounding East Palestine. Those in a red zone close to the derailment are in "grave danger of death" if they remain in place, while those in a farther, yellow zone risk "seriously lung damage" if they don't evacuate, he said.

DeWine said law enforcement had been knocking on doors in the area Sunday night ordering people to leave. He said, "we have no knowledge that anybody's left."

An official with Norfolk Southern Railway said Monday that the controlled release will take between one to three hours, depending how much chemical has burned off already.

"The process we’re going to do today, we’re going to place a small shaped charge, it's going to create a hole about 2 to 3 inches into the tank car. This will allow the material to come out of the tank car, it’ll go into a pit and trench that we have dug and set up for this operation. Inside that trench will be flares … That will then light off the material," the official said.

"We’re doing this so that we can control these tank cars we have concern with. This allows us to control that operation and not have the car seat and do it itself."

Concern surrounding the chemicals in the derailed train mounted on Sunday, when DeWine's office said unstable temperatures in a car transporting chemicals could lead to an explosion.

"Within the last two hours, 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 governor's office said in a statement.

The governor's office said residents with children who stay could be arrested. It cited a threat made by the Columbiana County Sheriff's Office.

At 8 p.m., the governor ordered Ohio National Guard troops to East Palestine to help local authorities, his office said.

A train aficionado whose backyard faces the east-west railway used by Norfolk Southern said the area of the derailment is a straight section.

Federal investigators have focused in part on the role of a possible mechanical malfunction in the probe into the cause of the derailment, officials said Sunday.

The train's crew said an alarm indicating such a malfunction sounded just before the accident, Graham said at a news conference.

In addition, two videos of the train obtained by NTSB investigators show one of the rail cars may have had a broken or malfunctioning axle, Graham said Sunday.

The crew — an engineer, a conductor and a conductor trainee — were able to help bring the train to a stop Friday night and then disconnect its three engines from its cars, many of them burning, officials said. No injuries were initially reported.

Graham on Sunday identified at least 10 of the derailed cars as "hazmat cars," or those carrying hazardous materials or chemicals.

Vinyl chloride, which is used to make polyvinyl chloride (PVC) pipes, vehicle upholstery and picnic utensils, has been linked to increased risk of liver, brain and lung cancer, as well as some cancers of the blood, according to the Centers for Disease Control and Prevention.

Environmental Protection Agency personnel have been in East Palestine since Friday night and were monitoring air and water, two EPA officials said at Sunday's news conference.

In a statement Saturday, the village of East Palestine said "zero health risks" had been discovered so far.

"The village's drinking water is safe to drink and is being continually monitored," it said.

The NTSB was leading the investigation.

Dennis Romero is a breaking news reporter for NBC News Digital.

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