An explosion occurred Monday at a steel factory in Clairton, Pennsylvania, authorities said. A spokesperson for Allegheny County said a rescue operation was underway at U.S. Steel Clairton Coke Works for people trapped under the rubble.

An explosion Monday at a U.S. Steel coking plant near Pittsburgh has left people trapped under the rubble, with emergency workers on site trying to rescue them, an official said.

A major rescue mission is underway at the US Steel Clairton Coke Works plant near Pittsburgh, Pennsylvania, which exploded and left several people injured - while others remain trapped under rubble