Emergency crew gather after an explosion at the Clairton Coke Works, a U.S. Steel coking plant, Monday, Aug 11, 2025, in Clairton, Penn. (AP Photo/Gene Puskar)
CLAIRTON, PA – An explosion at a U.S. Steel plant near Pittsburgh left one dead and dozens injured or trapped under the rubble Monday, with emergency workers on site trying to rescue victims, officials said.
The explosion sent black smoke spiralling into the midday sky in the Monongahela Valley, a region of the state synonymous with steel for more than a century. An Allegheny County emergency services spokesperson, Kasey Reigner, said one person died in the explosion and two were currently believed to be unaccounted for. Multiple other people were treated for injuries, Reigner said.
Allegheny County Emergency Services said a fire at the plant started around 10:51 a.m. The explosion sent a shock through the community and led to officials asking residents to stay away from the scene so emergency workers could respond.
“It felt like thunder,” Zachary Buday, a construction worker near the scene, told WTAE-TV. “Shook the scaffold, shook my chest, and shook the building, and then when we saw the dark smoke coming up from the steel mill and put two and two together, and it’s like something bad happened.”
Dozens were injured and the county was sending 15 ambulances, on top of the ambulances supplied by local emergency response agencies, Reigner said.
Air quality concerns and health warnings
The plant, a massive industrial facility along the Monongahela River south of Pittsburgh, is considered the largest coking operation in North America and is one of four major U.S. Steel plants in Pennsylvania that employ several thousand workers.
Democratic Sen. John Fetterman, who formerly served as the mayor of nearby Braddock, called the explosion “absolutely tragic” and vowed to support steelworkers in the aftermath.
“I grieve for these families,” Fetterman said. “I stand with the steelworkers.”
The Allegheny County Health Department said it is monitoring the explosion and advised residents within 1 mile (1.6 kilometers) of the plant to remain indoors, close all windows and doors, set air conditioning systems to recirculate, and avoid drawing in outside air, such as using exhaust fans. It said its monitors have not detected levels of soot or sulfur dioxide above federal standards.
The plant converts coal to coke, a key component in the steel-making process. According to the company, it produces 4.3 million tons (3.9 million metric tons) of coke annually and has approximately 1,400 workers.
