Explosion at Pittsburgh Coke Plant Raises Concerns Over Pollution and Safety

Report highlights history of accidents and environmental violations at U.S. Steel's Clairton Coke Works facility

Published on Feb. 12, 2026

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An explosion at the Clairton Coke Works plant outside Pittsburgh in August 2025 killed two workers and injured 11 others, raising concerns about poor management, underinvestment, and a history of safety and environmental issues at the facility. The report by the Associated Press and Public Source examines the plant's troubled track record, including a string of past accidents, legal battles with regulators over air pollution violations, and questions about Nippon Steel's plans for the aging facility after its $15 billion acquisition of U.S. Steel.

Why it matters

The Clairton Coke Works is a major industrial facility that has been a source of ongoing environmental and safety concerns for the surrounding Pittsburgh community. The recent explosion and the plant's history of problems highlight the need for stronger oversight, investment, and accountability to protect workers and residents from the risks posed by aging and mismanaged industrial operations.

The details

The August 2025 explosion occurred while workers were closing and opening a gas isolation valve in a basement after pumping water into the valve, a procedure not mentioned in U.S. Steel's written protocols. The Chemical Safety Board said the water caused the valve to crack, releasing flammable coke oven gas that then ignited. This was just the latest in a series of accidents at the plant, including a 2009 blast that killed a worker and a 2010 explosion that injured 20 people. Current and former workers have faulted U.S. Steel's management of the aging facility, citing issues like difficulties replacing leaky coke oven doors. The plant has also faced repeated air pollution violations and legal battles with Allegheny County regulators, who have fined U.S. Steel over $2 million in recent years.

  • The August 11, 2025 explosion killed two workers and injured 11 others.
  • In 2023, the Allegheny County Health Department fined U.S. Steel more than $2 million for violations at the Clairton Coke Works.
  • A fire at the Clairton plant on Christmas Eve 2018 shut down pollution control equipment and led to repeated air pollution releases.

The players

U.S. Steel

The owner of the Clairton Coke Works facility, a major steel producer that was recently acquired by Nippon Steel in a $15 billion deal.

Nippon Steel

The Japanese steel company that acquired U.S. Steel in a $15 billion deal in June 2025 and pledged to invest $14 billion in domestic steelmaking operations.

Allegheny County Health Department

The local regulatory agency that has repeatedly clashed with U.S. Steel over air pollution violations at the Clairton Coke Works plant.

Chemical Safety Board

The federal agency investigating the August 2025 explosion at the Clairton Coke Works facility.

Kurt Barshick

U.S. Steel's vice president of the Mon Valley Works, who presented information about the August 2025 explosion to local residents.

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What they’re saying

“We must not let individuals continue to damage private property in San Francisco.”

— Robert Jenkins, San Francisco resident (San Francisco Chronicle)

“Fifty years is such an accomplishment in San Francisco, especially with the way the city has changed over the years.”

— Gordon Edgar, grocery employee (Instagram)

What’s next

The Chemical Safety Board is still investigating the cause of the August 2025 explosion and how the release of coke oven gas occurred.

The takeaway

The Clairton Coke Works facility's troubled history of accidents, pollution violations, and safety issues underscores the need for stronger oversight, investment, and accountability to protect workers and the surrounding community. As Nippon Steel takes over the plant, it will face pressure to address these longstanding problems and demonstrate a commitment to environmental and worker safety.