Residents of a small village in northeast Ohio are being urged to evacuate as workers try to prevent a "catastrophic tanker failure" and explosion that could release toxic gas and shoot deadly shrapnel up to a mile away.

On Friday, a 150-car train derailed while transporting dangerous chemicals through East Palestine, Ohio, leading Gov. Mike DeWine to issue an evacuation order on Sunday evening for people living within a mile of the train derailment.

The threat of a major explosion initially emerged Sunday night, after one of the derailed train cars experienced a drastic temperature change, according to DeWine. He added that a majority of residents left prior to the evacuation notice, but at least 500 people had refused. Families with children who fail to evacuate could face possible arrest.

The Columbiana County Emergency Management Agency said they are monitoring the air quality and sampling the water in a nearby stream for any contamination.

There have been rising concerns about hazardous materials like vinyl chloride, butyl acrylate, and combustible liquids contained in the derailed cars.

Vinyl chloride, which is highly flammable and primarily used to make polyvinyl chloride (PVC) pipes, vehicle upholstery, and picnic utensils, is also linked to an increased risk of cancer, and it can be toxic at the level of emitting a scent humans can smell.

"If a water supply is contaminated, vinyl chloride can enter household air when the water is used for showering, cooking, or laundry," the National Cancer Institute says.

As of Sunday afternoon, officials told residents that the air and drinking water was safe.

About 50 cars of a Norfolk Southern train went off track in East Palestine on Friday around 9 p.m. local time. The train was eastbound heading from Madison, Illinois, to Conway, Pennsylvania.

The derailment led to a days-long fire that caused a strong odor around the area, according to NPR-affiliate WOSU

Residents are not expected to be allowed to return to the 1-mile evacuation zone for the foreseeable future.

"As of 8 a.m. this morning – the 1-mile evacuation zone will be enforced and you will not be able to enter the evacuation zone," the village of East Palestine posted Monday on Facebook. Those outside the zone are asked to stay indoors and avoid travel "to keep the roadways clear for emergency services," officials said.

The agency investigating the derailment, the National Transportation Safety Board, said in a press conference Sunday that the probe is ongoing and preliminary findings indicate one of the railcar axles experienced mechanical issues.

East Palestine is a village of about 5,000 people near the Ohio-Pennsylvania border.

U.S. Explosion