Gas valve failure caused deadly Clairton blast, U.S. Steel says
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U.S. Steel's Clairton Coke Works on Aug. 11, 2025. Photo: Chrissy Suttles/Axios
A gas valve failure caused the explosion at Clairton Coke Works on Monday morning that killed two people, U.S. Steel said Friday.
Why it matters: The massive Mon Valley facility — one of the largest coke plants in the world — has a long history of environmental and safety violations. The latest explosion is fueling renewed scrutiny from regulators and the public over U.S. Steel's operations and transparency.
- Authorities have identified the victims as 52-year-old Steven Menefee and 39-year-old Timothy Quinn. At least 10 others were injured in the blast.
Driving the news: Preliminary indications point to the explosion occurring when a gas valve was flushed in preparation for routine maintenance, according to a statement from U.S. Steel.
- "Pressure built inside the valve, leading to valve failure and coke oven gas filling the area and ultimately exploding when finding an ignition source," reads the statement. "We want to reinforce that this investigation is in its early stages, and we will provide more information when we can."
State of play: Clairton Coke Works — a 400-acre complex in the Mon Valley — produces coal-based fuel used in steelmaking and employs about 1,300 people.
- The facility has faced years of scrutiny over air quality violations, fires and other safety incidents.
Between the lines: Gas from ovens in one section of the plant — grouped in rows known as batteries — exploded and caused sudden pressure bursts in another section, creating two additional loud booms that were initially mistaken for explosions, U.S. Steel senior vice president and chief manufacturing officer Scott Buckiso said Tuesday.
The fine print: U.S. Steel officials, the U.S. Chemical Safety and Hazard Investigation Board and other agencies are investigating the explosion by reviewing video and interviewing employees.
What's next: "We continue to strive to share information with our affected families and employees first, particularly those in Clairton," reads the U.S. Steel statement. "Our focus remains on our employees and their families during this difficult time."