All but two of the 109 cars being hauled were tanker cars, officials said. One person was treated for potential inhalation issues, but no other injuries were reported, according to a statement from CSX, the train company.
Officials evacuated hundreds of families and shut down two water treatment plant following the Monday afternoon derailment. The West Virginia National Guard was taking water samples to determine whether the oil had seeped into a tributary of the Kanawha River, state public safety division spokesman Larry Messina said.
Federal railroad and hazardous materials officials are probing the accident, in which part of the train formation hit a house. The office of Gov. Earl Ray Tomblin, which has issued a state of emergency, said the tanker cars were loaded with Bakken crude from North Dakota and headed to Yorktown, Virginia.
The U.S. Transportation Department is weighing tougher safety regulations for rail shipments of crude, which can ignite and result in huge fireballs.