Authorities said their investigation has shifted to the cause of the explosion after they accounted for everyone who was missing.

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.

Two people have died and 10 are injured following an explosion at a Pennsylvania steel plant on Monday, Allegheny County police said.