Authorities on Monday completed the release of toxic chemicals that had been transported on a train that derailed over the weekend in eastern Ohio. Authorities had warned that the chemical could be deadly if inhaled.

The release of vinyl chloride, a toxic and flammable gas used to produce vehicle interiors and PVC pipes, was completed Monday afternoon after evacuations spread from East Palestine, Ohio, the site of Friday’s derailment by overnight, to an adjacent community in Pennsylvania.

The launch was «successfully completed,» according to the train’s operator, Norfolk Southern. The burning of material would continue after dark, he said.

Parts of a Norfolk and Southern freight train that derailed Friday night are still burning at noon, in East Palestine, Ohio, on Saturday.Gene J. Puskar/AP

A federal Emergency Alert System message on Monday urged residents in eastern Palestine and the Pennsylvania township of Darlington to leave immediately.

Ohio Gov. Mike DeWine’s office said late Sunday that 500 people had defied orders to leave, but said Monday he believed all had left.

The Ohio National Guard deployed to the area Sunday night and authorities went door-to-door urging stragglers to move, DeWine said at a Monday news conference.

“Those in the red area are in serious mortal danger if they are still in that area,” the governor warned.

Two of the five train cars carrying vinyl chloride were likely filled with the gas, and temperature changes could have triggered it, authorities said at the news conference.

That left leaders with two poor choices: release a gas known to be potentially deadly if inhaled and associated with increased cancer risk, or back off for an extended period of time amid the possibility of an explosion at the site. of the derailment.

Officials said an explosion would come with two dangers, including the same one that comes with a controlled release, exposure to a hazardous material.

«The vinyl chloride contents of five rail cars are currently unstable and could potentially explode, causing a deadly outpouring of shrapnel and toxic fumes,» the Ohio governor said.

Two cars believed to be filled with vinyl chloride each contained 177,000 pounds of the chemical, a National Guard officer said. It was not clear how much was in the others. All five were subject to controlled release and burning, authorities said.

The released material would reach an adjacent well and ignite from flares placed on the feature, authorities said.

«We’re going to put a small shaped charge, it’s going to create about a 2- to 3-inch hole in the tank car,» said Scott Deutsch, Norfolk Southern’s regional manager for hazardous materials. «This will allow the material to exit the tank car.»

Environmental Protection Agency staff have been in eastern Palestine since late Friday and were monitoring air and water, with no sustained signs of toxicity for eastern Palestine, agency officials said Monday.

A state environmental safety official said runoff from the train’s subsequent fire and firefighting efforts reached a natural waterway, but authorities stopped the flow. Fish in the area were affected, the official said.

The derailment was reported at 8:55 p.m. Friday as the 150-car train was en route from Matteson, Illinois, to Conway, Pennsylvania. It was estimated that 50 cars were off the track.

No injuries were reported, including among the train’s three-person crew.

Initial observations from the National Transportation Safety Board, which is leading the investigation into the cause of the derailment, include video evidence and inspection of a broken axle on one of the cars, a board member said Sunday.

joseph cradduck, Clara Secrist, christian santana and marin scott contributed.