CLAIRTON, Pa. (BN24) — A devastating explosion ripped through a U.S. Steel plant near Pittsburgh on Monday, killing one worker and leaving another missing while sending at least 10 people to area hospitals, officials said.
The blast at the sprawling Clairton coking facility occurred around 10:51 a.m., sending towering plumes of black smoke into the midday sky and heavily damaging the industrial complex along the Monongahela River. Emergency workers continued searching through charred rubble Monday afternoon for the missing employee as investigators worked to determine what caused the explosion.
The initial blast was followed by several smaller explosions that could be felt throughout the surrounding community, prompting Allegheny County officials to urge residents to stay away from the area to allow emergency responders to work safely.
“It felt like thunder,” said Zachary Buday, a construction worker near the scene. “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.”
One worker was pulled from the wreckage hours after the explosion struck the facility, which is considered the largest coking operation in North America and employs approximately 1,400 people. The plant converts coal to coke, a crucial component in steel production, through a process that involves baking coal in specialized ovens at extreme temperatures.
At a news conference, Scott Buckiso, U.S. Steel’s chief manufacturing officer, declined to provide specific details about the extent of damage or casualties. He praised company employees for their response, saying they “did a great job” of rescuing workers, shutting down gas lines and stabilizing the site.
Buckiso said the company, now a subsidiary of Japan-based Nippon Steel Corp., is cooperating fully with authorities investigating the incident. Search teams were still looking for one missing person, he said, adding that they believed they knew the general location but were not certain.
“Obviously, this is a tragedy that we want to understand,” Buckiso said.
Medical facilities across the region treated victims from the explosion. Allegheny Health Network said it treated seven patients from the plant, discharging five within hours. The University of Pittsburgh Medical Center said it was treating three patients at UPMC Mercy, the region’s only level one trauma and burn center.
The explosion’s impact extended beyond the plant’s boundaries. Amy Sowers, a 49-year-old Clairton resident sitting on her porch less than a mile from the facility, felt her house shake from the blast.
“I could see smoke from my driveway,” she said. “We heard ambulances and fire trucks from every direction.”
Sowers decided to leave the area after detecting a faint smell in the air. A lifelong Clairton resident, she has witnessed several incidents at the plant over the years and said many residents cannot afford to move despite health concerns.
“Lives were lost again,” Sowers said. “How many more lives are going to have to be lost until something happens?”
The Clairton plant has experienced multiple serious incidents in recent years. A maintenance worker died in an explosion at the facility in September 2009, and another blast in July 2010 injured 14 employees and six contractors. According to Occupational Safety and Health Administration records, the most recent workplace fatality occurred in 2014 when a worker was burned and died after falling into a trench.
Following the 2010 explosion, OSHA fined U.S. Steel and a subcontractor $175,000 for safety violations. The company appealed its citations and $143,500 in fines, which were later reduced under a settlement agreement.
Despite Monday’s explosion, the Clairton coking plant continued operating, though officials said two batteries where the explosion occurred were shut down.
The facility’s coking process creates coke gas, a lethal mixture of methane, carbon dioxide and carbon monoxide that poses significant safety risks. The plant bakes coal for hours at high temperatures to remove impurities that could weaken steel during production.
Clairton Mayor Richard Lattanzi expressed sympathy for the victims and their families.
“The mill is such a big part of Clairton,” he said. “It’s just a sad day for Clairton.”
As a precautionary measure, the Allegheny County Health Department advised residents within one mile of the plant to remain indoors and close all windows and doors. The department said its air quality monitors had not detected levels of soot or sulfur dioxide above federal standards.
The explosion adds to the plant’s troubled environmental record. In recent years, the facility has faced persistent pollution concerns and legal challenges from environmental groups and health officials.
In 2019, the plant agreed to settle an air pollution lawsuit for $8.5 million. Last year, the company committed to spending $19.5 million on equipment upgrades and $5 million on local clean air initiatives as part of resolving a federal lawsuit filed by the Clean Air Council, PennEnvironment and the Allegheny County Health Department.
That legal action stemmed from a Christmas Eve fire in 2018 that caused $40 million in damage and damaged pollution control equipment, leading to repeated releases of sulfur dioxide. In the fire’s aftermath, county officials warned residents to limit outdoor activities, with many reporting that the air felt acidic, smelled like rotten eggs and was difficult to breathe for weeks.
Dr. Deborah Gentile, medical director of Community Partners in Asthma Care, studied asthma levels following the 2018 fire and documented a doubling of patients seeking medical treatment. Research by her colleagues found that patients living near the plant experienced increased asthma symptoms, including coughing, wheezing and shortness of breath.
News of Monday’s explosion prompted Gentile to question the facility’s maintenance standards.
“I’m very concerned that they aren’t keeping their equipment up to date and in shape,” she said.
The plant experienced another incident as recently as February, when a problem with a battery led to a “buildup of combustible material” that ignited, causing an audible explosion. Two workers received first aid treatment at a local hospital but suffered no serious injuries.
Environmental advocates are calling for a comprehensive review of the facility’s operations. David Masur, executive director of PennEnvironment, which has previously sued U.S. Steel over pollution violations, said there needed to be “a full, independent investigation into the causes of this latest catastrophe and a re-evaluation as to whether the Clairton plant is fit to keep operating.”
The explosion comes months after U.S. Steel and Nippon Steel in June finalized what they called a “historic partnership.” The deal gives the U.S. government input on certain matters and concludes a nearly $15 billion buyout that was delayed for more than a year due to national security concerns and presidential politics in Pennsylvania, a key battleground state.
The Mon Valley region, located south of Pittsburgh, has been synonymous with steel production for more than a century. The Clairton plant is one of four major U.S. Steel facilities operating in Pennsylvania and plays a crucial role in the company’s steel-making operations across North America.
As the investigation continues, the cause of Monday’s explosion remains unknown. Emergency officials said the search and rescue effort for the missing worker would continue, while county authorities maintained their advisory for nearby residents to avoid the area.
