Updated August 12 at 6:49 a.m.
Searchers on Monday night recovered the body of a second worker who died earlier in the day in an explosion at the U.S. Steel Clairton Coke Works — a blast so powerful that Clairton city officials said it could be felt at least two miles from the sprawling industrial complex on the Monongahela River.
That worker had been missing since late morning, when the explosion rocked the coke works shortly before 11 a.m., Allegheny County Emergency Services chief Matt Brown said during a news conference Monday night. Search crews recovered the person's body after "working vigorously" through the day in what they'd initially hoped would be a rescue effort at the plant, located about 15 miles south of Pittsburgh.
"Unfortunately, we now have a second deceased worker," Brown said. "That officially does bring our recovery side ... to a close."
Earlier in the day, county officials reported that another injured worker was pronounced dead at a hospital and two others remained missing after the explosion, prompting emergency crews to search throughout the day for people who may have remained trapped under rubble. The Allegheny County Medical Examiner's office identified the first worker who died as Timothy Quinn, 39.
Searchers found the other missing worker around 2:45 p.m. and transported that person to a hospital for treatment, Allegheny County Police Assistant Superintendent Victor Joseph said.
Brown said a total of 10 plant workers required hospital treatment for injuries suffered in the explosion — five who were listed in critical but stable condition Monday night, and five others who were treated and released. City and county officials said multiple people initially reported injuries after the explosion, but not all of them required hospital treatment. Authorities did not identify other people who died or were injured.
Part of U.S. Steel's Mon Valley Works, the Clairton plant converts coal to coke, a key component in the steel-making process. To make coke, coal is baked in special ovens for hours at high temperatures to remove impurities that could otherwise weaken steel. The process creates what’s known as coke gas — made up of a lethal mix of methane, carbon dioxide and carbon monoxide.
No information was immediately available on the cause of the explosion, but investigators from the U.S. Occupational Safety and Health Administration were on the scene Monday afternoon. Joseph said his agency also had been asked by Clairton police to assist with what he predicted would be a "time-consuming, technical investigation" of the explosion.
At an earlier news conference Monday afternoon, U.S. Steel executive vice president and chief manufacturing officer Scott Buckiso said the explosion occurred around 10:50 a.m. at the plant’s coke oven batteries 13 and 14. He said workers shut down gases and utilities used in that area, and that the rest of the coke works is "stable" and still operating.
In response to questions, Buckiso said the batteries were "in good condition ... productivity-wise, environmental-wise and safety-wise" before the explosion. Appearing later at the evening news conference, he said he had no new information to share "because all efforts have been on rescue."
The company, now a subsidiary of Japan-based Nippon Steel Corp., said emergency teams were immediately dispatched to the scene, but it offered no other details about the cause of the explosion or the extent of damage. In a statement earlier in the day, company CEO David Burritt said U.S. Steel is working with authorities to investigate the cause.
"Our hearts go out to our employees," Buckiso said during the afternoon news conference. "Safety is our No. 1 priority, every day, every shift — 365. This is a tragedy that we want to understand."
Allegheny Health Network said it treated seven patients from the explosion in its hospitals and discharged five of them within a few hours. The University of Pittsburgh Medical Center said it is treating three patients at UPMC Mercy, the region’s only level one trauma and burn center.
At least 20 emergency agencies and 14 local fire departments responded to assist U.S. Steel's in-house firefighting force after receiving the first reports of the explosion at 10:51 a.m., Brown said. That blast was followed by several smaller ones, according to Gov. Josh Shapiro and other officials.
"It's a very hot day. It's very taxing to all the emergency responders," Brown said. "The good news is, they work together very often ... many of them are volunteers at the same departments. Their efforts are very focused on rescue at this point."
A plant employee who asked not to be identified said he was working at 10:45 a.m. when he felt the impact of the explosion, between a quarter-mile and half-mile away from his location. The worker said his friend and fellow worker was in the lunchroom at the time and got "banged up" when the explosion knocked him out of his chair.
John LaBarbara, who said he worked at the coke works until a week ago, said his father and brother were in the plant when the blast occurred, but they were not injured. His father has been part of the plant maintenance team for 30 years and works in a building where compressors are repaired; his brother works on the other side of the plant.
"They were waiting on [LaBarbara's father] to get in the truck, load up and go down," LaBarbara said, "and then he said that's when it exploded ... when they were all getting in the truck to head over there."
Clairton resident Amy Sowers said she also felt her house shake from the explosion while she sat on her porch, less than a mile from the plant.
“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 she said she smelled a faint smell in the air.
A dark cloud of smoke could be seen over the plant after the explosion, and the county health department said it is "actively monitoring" the aftermath of the explosion, although it said it has not detected particulate matter or sulfur dioxide — components of air pollution that can cause health risks — above federal standards.
The health department initially advised people who live within a mile of the plant to stay inside — guidance reiterated at the afternoon news conference by County Executive Sara Innamorato — but lifted that advisory at 6:30 p.m. Monday.
The Clairton facility is the largest coke works plant in North America and a major employer and source of community identity in the region. Clairton Mayor Richard Lattanzi said his heart goes out to the victims of Monday's explosions.
“The mill is such a big part of Clairton,” he said. “It’s just a sad day for Clairton.”
Coke is used in a blast furnace to processiron ore into steel. It is made by heating coal to high temperatures, and the subsequent emissions are classified as carcinogens. The plant is by far the largest source of benzene and other pollutants in Allegheny County.
The site has drawn ire from public health and environmental advocates, who routinely raise concerns about pollution emitted from the facility that negatively impacts the region’s air quality. Following a catastrophic 2018 fire that destroyed pollution controls, asthma exacerbations rose among residents within 10 miles of the plant.
On Monday, those groups expressed sympathy for workers and the community while reiterating longstanding concerns.
The Breathe Project, a nonprofit environmental advocacy group, offered condolences for the "horrific impact of the explosion." In a statement, the group added that there had been repeated issues at the plan in recent years, and said, "Real progress will only come when public health and community revitalization are treated as non-negotiable priorities. There have been too many years of promise-breaking and too much emphasis on short-term deflections that continue to perpetuate community health harms and workforce anxiety."
A pair of environmental groups and the Allegheny County Health Department in 2018 sued U.S. Steel in federal court, winning a landmark settlement last year. The settlement required the closure of one of the plant’s coke batteries, as well as $19.5 million in upgrades to its coke oven gas cleaning facilities. The agreement also included $4.5 million for local communities impacted by the 2018 fire.
Combined with $17.5 million in upgrades the plant had undertaken since the federal lawsuit was filed, the total settlement of $42 million was the largest Clean Air Act citizen’s suit ever in Pennsylvania, according to the National Environmental Law Center, which represented environmental groups in the suit.
The coke works is among the region’s U.S. Steel facilities now owned by Japan-based Nippon Steel following a historic partnership agreement between the two companies. The combined company is the fourth-largest steelmaker in the world.
Nippon committed to investing $11 billion to upgrade U.S. Steel facilities in June. A spokesperson for Nippon did not immediately respond to a request for comment about Monday’s explosion.
The United Steelworkers union, whose members split on the transaction, said in a statement that it "has occupational health and safety experts and other representatives on the ground at the Clairton Works assessing the situation and aiding our members. While we are still determining the scope of the tragedy, we are aware that multiple workers are receiving medical treatment for their injuries." It pledged to "work with the appropriate authorities to ensure a thorough investigation and to see that our members get the support they need."
In a statement, Shapiro said the state Emergency Management Agency and state police have offered "all assistance" to emergency responders at the plant and in the Mon Valley.
"The scene is still active, and folks nearby should follow the direction of local authorities," the governor said. "Please join Lori and me in praying for the Clairton community."
U.S. Sen. John Fetterman, who lives in nearby Braddock, spoke with reporters gathered outside the plant after he entered the complex and spoke with some workers inside.
"Everyone's grim. Not surprisingly — you can't shut the facility down. It's like a big, gigantic ship in the middle of the ocean — you can't shut it down," he said. "They still have to work ... Everyone knows what happened. Obviously, it's very grim there."
Other elected officials also expressed sympathy and concern.
"My heart is with the workers, especially those injured or trapped, their families, first responders, USW members and the entire Clairton community," said U.S. Rep. Summer Lee, whose district includes the facility. "My office remains committed to ensuring that every affected worker and family receives the support and resources they need."
Julie Grant of The Allegheny Front and The Associated Press contributed to this report.
Copyright 2025 90.5 WESA
