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.

CLAIRTON, Pa. (AP) — An explosion Monday at a U.S. Steel plant near Pittsburgh has left people trapped under the rubble, with emergency workers on site trying to rescue them, an official said. There are no confirmed fatalities yet at the Clairton Coke Works, said Abigail Gardner, director of communications for Allegheny County.