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. — Explosions late Monday morning at Clairton Coke Works in Allegheny County killed two people and injured 10 others, as officials found one person who initially was missing.

Katie Boyd’s son was working at the plant when the explosion occurred around 10:30 a.m.

Corbin Boyd, 20, worked on the battery where the explosion occurred, but was able to immediately let his family know he was uninjured, his mother said.

“He was about 100 feet from it, from what I understand. He was in his break room when it happened … He felt the whole explosion,” she said. A friend of her son’s was among the injured and had to be flown by medical helicopter.

Early Monday afternoon, Katie Boyd and her family were waiting in the parking lot of the nearby Speedway convenience store for Corbin, who’d worked a double shift, to leave the plant.

“I don’t want him driving home, he is pretty shaken up,” she said.

Washington Mayor Jojo Burgess, who works at Clairton Coke Works, said his station is about 100 yards from where the explosion occurred.

“We all heard a loud boom and the ground shook,” Burgess said. “We walked out and saw one of the batteries had a lot of smoke coming out of it.”

He and the workers in his area then went to their pre-designated “muster point” to be accounted for as emergency crews responded to the explosion site.

“I’m here. I’m not in any danger,” Burgess said. “But it’s a pretty bad scene down here.”

Scott Buckiso, executive vice president and chief manufacturing officer of U.S. Steel’s North American Flat-Rolled Segment, said the conditions of the 10 workers who were transported were unknown as of 4 p.m.

Buckiso said the plant is stable, and safety remains the company’s “number one priority.” Besides the Battery 13 and 15 sections, the mill continued operations after the explosion, Buckiso said.

Two employees had been unaccounted for; one was found after 3 p.m., said Victor Joseph, Assistant Superintendent of Allegheny County Police.

Allegheny County Police, officials from the Bureau of Alcohol, Tobacco, Firearms and Explosives and the fire marshal will conduct the “time consuming and technical investigation,” Victor said.

Democratic Sen. John Fetterman, who was at the plant, said the Occupational Safety and Health Administration was also there.

Asked what it was like to be near the scene of the explosions, Fetterman said it was “grim.”

“You can’t shut the facility down. … So they still have to work now, knowing that their co-workers may — everybody knows what happened,” Fetterman said.

Less than one mile from the plant, Amy Sowers, 49, felt her house shake.

“I could see smoke from my driveway,” she told the Associated Press. “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. Sowers, who grew up in Clairton, has seen several incidents at the plant over the years. Despite health concerns, she said many residents cannot afford to leave.

A maintenance worker was killed in an explosion at the plant in September 2009. In July 2010, another explosion injured 14 employees and six contractors.

“Lives were lost again,” Sowers said. “How many more lives are going to have to be lost until something happens?”

Deanna Forkey was working at Hometown Burgers and Deli near the plant and heard a loud “bang” around 10:30 a.m.

“It popped our door open,” Forkey said. “When I looked up, I just saw black smoke everywhere.”

According to Forkey, first responders arrived within minutes.

She called it a “scary thought” to consider the aftermath of the explosion and potential victims.

“I know people that work there. I’ve built a little bit of a relationship with some of the customers who work over there,” Forkey said.

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.

In a statement, U.S. Steel said an “incident” occurred at the plant’s coke oven batteries 13 and 14. The company, now a subsidiary of Japan-based Nippon Steel Corp., said emergency teams were immediately dispatched to the scene, but it gave no other details about the cause of the explosions, casualties or damage.

The 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.

The Allegheny County Health Department initially advised residents within 1 mile of the plant to remain indoors, close all windows and doors, set air conditioning systems to recirculate, and avoid drawing in outside air. By 6:30 p.m., the department lifted that advisory.

According to the company, the plant produces 4.3 million tons (3.9 million metric tons) of coke annually and has approximately 1,400 workers.

The Associated Press contributed to this report.