As federal investigators worked to find out why a 150-car train derailed in northeastern Ohio, the state's governor warned late Sunday that unstable temperatures in a car transporting chemicals could lead to an explosion.
The area most at risk of being affected by the Friday crash, that within a 1-mile radius of the crash in the village of East Palestine, was evacuated by early Saturday and remained off-limits, officials said.
But Gov. Mike DeWine's office said an estimated 500 residents remained behind in the 1-mile zone. It said they were subject to an "urgent warning" to evacuate.
"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.