Workers were heating coal and preparing for routine maintenance when an explosion rocked a U.S. Steel plant outside Pittsburgh

Two people are dead and 10 others injured after an explosion at U.S. Steel’s Clairton Coke Works near Pittsburgh. The recovery operation has ended, and the cause is under investigation.

Ten people were hospitalized after the blast at a coke plant in Clairton, Pa., near Pittsburgh. One person who had been missing was found dead late on Monday.

The explosion, followed by several smaller blasts, could be felt in the nearby community and prompted county officials to warn residents to stay away from the scene so emergency workers could respond.

After an explosion rocked a steel plant outside Pittsburgh on Monday, workers scrambled into the wreckage alongside firefighters. A cloud of black smoke rose above a charred pickup truck as rescuers sprayed the scene with streams of water.

The mill, which is part of the recent merger between U.S. Steel and Nippon Steel, has faced scrutiny from federal and local regulators.