One person has died, one person is unaccounted for and at least 10 are injured following an explosion at a U.S. Steel plant near Pittsburgh, Allegheny County Police Assistant Superintendent Victor Joseph said at a press conference Monday afternoon.

Two people have died and 10 are injured following an explosion at a Pennsylvania steel plant on Monday, Allegheny County police said. The incident at the U.S. Steel Clairton Coke Works plant in Clairton, about 15 miles outside of Pittsburgh, trapped people under rubble, prompting a rescue operation, according to Allegheny County officials.

Authorities confirmed a second fatality after an explosion at the U.S. Steel Clairton Coke Works facility outside of Pittsburgh.