Steel plant explosion in Pennsylvania preceded by multiple incidents

(NewsNation) — The U.S. Steel plant where two people were killed and at least 10 others were hurt on Monday has been home to recent accidents and regulatory violations.

Clairton Coke Works, a massive industrial facility along the Monongahela River south of Pittsburgh, is considered the largest coking operation in North America, NewsNation local affiliate WHTM reported.

The plant has lost millions of dollars in fines and sent workers to the hospital for accidents as recently as this past winter.

Previous incidents at Clairton Coke Works

In February 2025, a battery fire caused an audible boom and sent two workers to the hospital, local media reported.

A year before that, the Allegheny County Health Department fined U.S. Steel nearly $2 million for violating the Clean Air Act more than 360 times, according to department records.

The county also fined U.S. Steel for hydrogen sulfide pollution in December 2023.

And on Christmas Eve 2018, a massive fire caused $40 million in damage — knocking pollution controls offline and leading to days of sulfur dioxide spikes, CBS News reported.

U.S. Sen. John Fetterman referenced that fire on Monday.

“It just reminds people of how dangerous of a job that this is. … To me, it reminds me of that huge fire that happened Christmas Eve five to six years ago, and they were able to bounce back and in record time,” he told reporters on the scene.

Since that blaze, the factory has spent millions on lawsuits, settlements and emission cuts.

U.S. Steel, now partnered with Nippon Steel, said it is cooperating with investigators and called worker safety a top priority “every day, every shift, 365.”

Investigators are still looking into the cause of Monday’s blast.