The federal government claims U.S. Steel could have prevented a deadly explosion at Clairton Coke Works near Pittsburgh on Aug. 11, 2025, which resulted in two fatalities and 11 injuries.
The U.S. Chemical Safety and Hazard Investigation Board (CSB) released a final report stating that the company lacked a procedure for safely conducting maintenance involving the closure and reopening of a valve supplying toxic and flammable gas. The Clairton Coke Works, built in 1901, is integral to the steelmaking process.
CSB Chairperson Steve Owens stated in a press release that the accident “should never have happened.”
The CSB criticized U.S. Steel for lacking a formal valve-washing protocol and failing to build structures that could withstand explosions. They highlighted the absence of effective process-safety management systems, which could have mitigated the $52.5 million in property damage caused by the explosion.
The CSB report also noted the absence of formal procedures affecting U.S. Steel’s valve-cleaning contractor, MPW, which did not comment on the findings.
The incident stemmed from the over-pressurization of a double-disc gate valve, releasing flammable gas that exploded, according to the 85-page CSB report.
In February, the Occupational Safety and Health Administration cited U.S. Steel for several violations and fined the company $118,214. U.S. Steel is contesting these violations in federal court.
In June 2025, U.S. Steel became a subsidiary of Japan’s Nippon Steel Corp., retaining its brand and Pittsburgh headquarters.
In a statement, U.S. Steel announced it has implemented best practices for valve cleaning and improved procedural assessments. However, according to Matt Mehalik, executive director of the Breathe Project, it’s unclear if U.S. Steel has taken steps to prevent future incidents. The Allegheny County Health Department fined U.S. Steel at least $15.3 million for air-quality violations from 2021 to 2025.
Mehalik noted the lack of documented accountability or enforcement actions following the explosion, which remains the responsibility of OSHA and the Allegheny County Health Department.
On Aug. 10, 2026, the Breathe Project commended the CSB’s report but criticized U.S. Steel and Nippon for not updating safety processes to prevent similar events.
The CSB urged U.S. Steel to evaluate building siting at the Clairton plant, create valve-washing procedures, and conduct a safety analysis of this process. The agency also called for industry-wide adoption of robust safety-management principles for hazardous tasks.
Original Story at insideclimatenews.org