Investigators from the National Transportation Safety Board’s (NTSB) office of Railroad, Pipeline, and Hazardous Materials are in communication with the Federal Railroad Administration and CSX emergency response crews on Monday’s train derailment near Mt. Carbon, West Virginia.

At least 28 tank cars of a 109-car CSX train carrying more than 3 million gallons of crude oil derailed, slammed into each other and leaked oil onto the ground, which immediately ignited. Emergency crews allowed the fire to burn out. Hundreds of residents within a half mile of the derailment were evacuated. At least one injury was reported.

Investigators say it’s likely that some of the crude oil entered the river; downstream water treatment intakes on the Kanawha River were closed as a precaution.

The cause of the derailment is unknown at this time. The NTSB says it will continue to monitor the situation.

“This accident is another reminder of the need to improve the safety of transporting hazardous materials by rail,” said NTSB Acting Chairman Christopher A. Hart. “That is why this issue is included on our Most Wanted List. If we identify any new safety concerns as a result of this derailment, the Board will act expeditiously to issue new safety recommendations.”

Additional information on rail tank car safety and the Most Wanted List can be found at: http://www.ntsb.gov/safety/mwl/Pages/mwl5_2015.aspx