On Friday, a train derailed in East Palestine, OH which caused a fire that burned for days. It has been closely monitored since the derailment, and the governors of Pennsylvania and Ohio have decided to take action.

The train is carrying vinyl chloride in several train cars which is an unstable chemical at risk of explosion and toxic gases being released into the air. One car, in particular, is of concern to railway officials since its safety valves are malfunctioning. Because of this, they keep the chemical from being safely released.

Health officials have urged the nearby residents to evacuate for their safety. They share that high levels of vinyl chloride could cause someone to lose consciousness, have serious skin burns, have lung damage or die. It can also cause sleepiness, dizziness and headaches. It can even cause cancer in the liver, brain, lungs and blood.

The National Cancer Institute warns that if the vinyl chloride contaminates water, it could enter homes and air when water is used to do laundry, cook or shower.

Officials have backed up their concern for safety by threatening residents with an arrest for misdemeanor charges of misconduct in an emergency. Officials have no date or time in mind for when residents will be able to return, but for now, their one-mile radius will stay in place.

At 3:30 p.m. on Monday, the railway crews will conduct a controlled release of the chemicals in an attempt to avoid a catastrophic event. The fires from this attempt are projected to burn anywhere from 1 to 3 hours.

If this attempt fails, a “catastrophic” explosion could occur. The main concern of a failure comes from the malfunctioning train car with an extreme temperature change.

Fire Chief Keith Drabick says that measures are being taken to avoid this disaster, but if it fails, “it will produce hydrogen chloride and phosgene gas into the atmosphere.”

“The vast majority of hazardous materials shipped by rail tank car every year arrive safely and without incident, and railroads generally have an outstanding record in moving shipments of hazardous materials safely,” says the US Department of Transportation’s Federal Railroad Administration.

Investigations are underway for the cause of the derailment. The fire has made it hard to investigate the site, and the main concerns are still mainly the risk of explosions.

It is still unclear how long it will take to clean up the derailed cars and the hazardous material, but it is estimated to take four to six weeks.