Early history Steelmaking in Clairton dates back to at least 1903, when the newly-formed
U.S. Steel purchased a half-interest in the
Crucible Steel Company of America's furnace and steel factory in the city. Two U.S. Steel workers were killed and 11 others, including contractors, were injured. An initial explosion occurred at 10:51 am inside a coke battery operating area, inside the reversing room, between the 13th and 15th battery, and multiple secondary explosions were reported afterwards. A fire broke out, but the plant was stable by the afternoon, with the plant and a vehicle damaged. Initially, one worker was reported to be dead and one was missing, but after a search and rescue effort, the missing worker was also later found dead. Ten injured workers were transported to local hospitals (
UPMC Mercy and
Allegheny Health Network) for care. Many of the injuries were not life-threatening, and five workers were discharged within a few hours.
Allegheny County Health Department officials were monitoring air quality in the area and recommended that residents within one mile stay indoors, but did not detect a change in air quality above federal standards. The order was lifted later in the day. As of February 2026, the explosion and its cause are still under investigation by the
Chemical Safety Board (CSB). Per the
Associated Press and ''Pittsburgh's Public Source'': The head of the CSB investigation said the explosion saw a "release of coke oven gas"—which the agency was still investigating—which "contacted an ignition source" and exploded. In December 2025, the CSB said it had identified "potentially unmitigated hazards for workers at Clairton Coke Works that warrant immediate attention." == Gallery ==