An explosion at U.S. Steel's Clairton Coke Works outside Pittsburgh killed two people and sent at least 10 to area hospitals Monday, heavily damaging part of the sprawling Mon Valley facility and sending a plume of black smoke over nearby neighborhoods, officials said.\n\nWhat Happened: Allegheny County authorities said the blast and ensuing fire began around 10:50–10:51 am, prompting a large multi-agency response and a brief 'stay indoors' advisory that was later lifted after monitors detected no exceedances of soot or sulfur dioxide, according to a WTAE-TV report.\n\nZachary Buday, a construction worker near the site, told WTAE-TV, 'It felt like thunder… Shook the scaffold, shook my chest, and shook the building,' adding that dark smoke began rising from the mill. One worker was pulled alive from the rubble hours after the blast. Officials later confirmed two fatalities as search-and-rescue operations concluded.\n\nU.S. Steel executives offered few details about the cause. Chief Manufacturing Officer Scott Buckiso, speaking to the Associated Press, said the company was still determining what happened and that employees 'did a great job' rescuing co-workers and shutting down gases to stabilize the site.\n\nChief Executive David B. Burritt pledged a thorough review, saying, 'I end every meeting and every message with the words, ‘Let's get back to work safely.' That commitment has never been more important and we will honor it.' The company, now part of Japan-based Nippon Steel, said it is coordinating with local and federal authorities.\n\nWhy It Matters: The Clairton complex, North America's largest coking operation, has a history of serious incidents and pollution disputes, drawing scrutiny from regulators and environmental groups. The blast comes weeks after U.S. Steel finalized a $14–$15 billion deal with Nippon Steel that added U.S. government oversight to the storied American brand.\n\nPennsylvania Gov. Josh Shapiro (D) said his administration is coordinating with local officials and that the Pennsylvania Emergency Management Agency and state police have offered assistance.\n\nRep. Summer Lee (D), whose district covers much of Allegheny County, wrote that her 'heart is with the workers, especially those injured or trapped, their families, first responders, and the entire Clairton community.'

US Steel Clairton Coke Plant Rocked By Explosion: 2 Dead, 10 Injured

An explosion at U.S. Steel's Clairton Coke Works outside Pittsburgh killed two people and injured at least 10, damaging part of the facility and sending black smoke over nearby neighborhoods. The blast occurred around 10:50–10:51 a.m. on August 12, 2025, prompting a multi-agency response and a temporary 'stay indoors' advisory, which was later lifted due to no detected soot or sulfur dioxide exceedances. U.S. Steel executives provided limited details, with Chief Manufacturing Officer Scott Buckiso stating the cause is still under investigation and employees performed well in rescuing co-workers and shutting down gases. Chief Executive David B. Burritt pledged a thorough safety review, emphasizing a commitment to safe operations. The incident occurs at North America's largest coking operation, which has a history of pollution and safety issues. The event follows a recent $14–15 billion deal between U.S. Steel and Japan-based Nippon Steel, which included U.S. government oversight.