Residents of East Palestine, Ohio, were told to urgently evacuate their town on Sunday night, two days after a train derailed in the area of about 4,700 residents.
Ohio authorities released toxic chemicals from five of the tanker cars after the derailment. Authorities hoped to reduce the threat of an explosion.
Norfolk Southern said in a statement to Scripps News, "The controlled breach of several rail cars has been completed successfully under the supervision of experts and first responders. Some of the material is now burning off consistent with expectations from the earlier models, and is expected to drain for a short number of hours. We have been, and will continue, monitoring air quality with the Ohio EPA. Remediation work at the site can now safely continue."
The derailment happened late on Friday and did not cause any injuries. Although two days had passed and Ohio Gov. Mike DeWine said late Sunday that officials measured a “drastic temperature change” in a rail car. He warned of a “catastrophic explosion” that could send shrapnel flying at least a mile away from the crash.
Gov. DeWine said most people within one mile had already evacuated, but he estimated that about 500 residents remained at the time of his warning.
"We've had a drastic change in the chemical inside the tank cars that we've been concerned about and watching all day, the vinyl chloride. We are at a risk now of a catastrophic failure of that container,” East Palestine Fire Department Chief Keith Drabick said at a news conference. “Measures are being taken to try and control that and prevent that from happening."
DeWine said Monday afternoon that the evacuation remains in place as officials plan a controlled release of the vinyl chloride. The controlled release began on Monday at 3:30 p.m. local time.
The controlled release was expected to last for about one to three hours, according to Scott Deutsch of Norfolk Southern Railway.
The derailment site is close to the Pennsylvania border with Ohio and the evacuation area extends into Pennsylvania as well.
“You need to leave. You just need to leave. This is a matter of life and death,” said DeWine Monday afternoon.
He said shelters were open for residents needing somewhere to go.
“Although teams are working to prevent an explosion from happening, residents living within a mile of the site are advised to immediately leave the area,” DeWine's office said in a statement.
Officials are still trying to determine what caused the derailment.
According to the Environmental Protection Agency, vinyl chloride is highly flammable and is mostly used to make polyvinyl chloride (PVC) plastic and vinyl products. Short-term exposure to the chemical can cause dizziness, drowsiness and headaches. Long-term exposure can result in liver damage and cancer concerns, the EPA said.