An explosion at a U.S. Steel plant in Clairton, Pa., on Monday killed at least one person and injured dozens more, with some still trapped under rubble, the authorities said.
Witnesses described feeling a shock wave and then seeing black smoke spew into the sky. Part of a building appeared to have been sheared off, and rubble littered the area.
Two people are missing, the Allegheny County Police Department said in a statement. Local hospitals said at least nine people were being treated for injuries from the explosion.
#BREAKING: An EXPLOSION has just occurred at a steel mill, video shows.
The incident occurred at the US Steel Clairton Coke Works plant near Pittsburgh, Pennsylvania.
Multiple people have been reported injured after being trapped under rubble.
PRAYpic.twitter.com/qLMgc631Is
— George (@anaveragegeorge) August 11, 2025
Update: U.S. Steel Vice President Scott Buckiso “There was one explosion that involved coke oven gas. The other two that were called explosions were actually relief pressure valves. When we had the issue on 13, 14 battery, we had some back pressure into 19, 20 battery. Those ruptured − gates is what they’re called − they did their job, they released.… Read more »