Chemical Safety Board Blasts U.S. Steel Over Fatal Clairton Coke Works Explosion
- Group Against Smog & Pollution
- 8 hours ago
- 2 min read
The U.S Chemical Safety Board on Monday issued its final report on the Aug. 11, 2025 explosion at U.S. Steel’s Clairton Coke Works that killed two people, injured 11 others, and caused an estimated $52.5 million in property damage.
The CSB is an independent federal agency charged with investigating, determining, and reporting to the public in writing the facts, conditions, and circumstances and the cause or probable cause of any accidental chemical release resulting in a fatality, serious injury, or substantial property damages.
Its biggest takeaway? The explosion could have been prevented.
The final report is 86 pages long and contains detailed analysis related to the incident, photographs depicting the aftermath of the explosion, and diagrams explaining what happened - we highly recommend folks take a look.
While you can read the entire report online, here are the key investigative findings:
Procedures and Hazard Analysis: On the day of the explosion, the valve washing operation was performed in a way that directly caused the catastrophic failure of the Battery 13 coke oven gas isolation valve. U.S. Steel occasionally utilized water washing to address valves that could not otherwise fully close, but the company never developed a formal procedure for water washing valves despite relying on it to prepare isolation valves for maintenance outages. Additionally, neither U.S. Steel nor its contractor, MPW Industrial Services, Inc, (MPW), identified or addressed the hazards created by applying pressurized water to the valve at a pressure greater than the valve’s design rating.
Facility Siting: The buildings in the Battery 13/14 transfer area were located less than 20 feet directly above the coke oven gas piping system. The buildings were routinely occupied by U.S. Steel personnel but were neither designed nor constructed to withstand an explosion. In the years leading up to the explosion, U.S. Steel had multiple opportunities to evaluate and address the inherent hazards resulting from the co-location of occupied buildings and the hazardous coke oven gas piping. “However, U.S. Steel affirmatively chose not to do so, based on the company’s belief that it was not required to do so,” the report states.
Process Safety Management Systems: U.S. Steel did not have sufficient process safety management systems that could have prevented or reduced the severity of this incident.
Stay tuned, GASP continues to follow this issue closely and will keep you posted as more information becomes available.
Editor’s Note: Here is some key coverage of the report:
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