Accident: United States Steel Corporation Clairton Plant Coke Oven Explosion
Location: Location: Clairton, PA
Accident Occurred On: 08/11/2025 | Final Report Released On: 08/10/2026
Accident Type: Explosion and Fire
Investigation Status: The CSB released its final report on August 10, 2026.
On August 11, 2025, at approximately 10:45 a.m. local time, an explosion at the United States Steel Corporation Clairton Plant coke oven batteries 13 and 14 caused two fatalities and multiple injuries.
Develop written policies and procedures in accordance with industry guidance such as NFPA 56 Standard for Fire and Explosion Prevention During Cleaning and Purging of Flammable Gas Piping Systems, governing cleaning piping systems containing flammable or toxic gas. Ensure that all workers who will or might participate in such operations are trained on the policies and procedures.
Develop and implement a corporate process safety governance program to ensure the implementation of process safety management at applicable facilities. At a minimum, this program shall:
a. include regular audits of subordinate facilities throughout the organization;
b. require the documentation of process safety deficiencies, when identified, and prompt corrective action; and,
c. incorporate industry guidance, such as the Center for Chemical Process Safety’s (CCPS) Guidelines for Implementing Process Safety Management, the CCPS’s Process Safety – Leadership from the Boardroom to the Frontline, and other industry good practice guidance publications.
Conduct a siting evaluation for all occupied and potentially occupied buildings at the Clairton Coke Works facility. Utilize the guidance contained in the Center for Chemical Process Safety’s Guidelines for Evaluating Process Plant Buildings for External Explosions, Fires, and Toxic Releases, the American Petroleum Institute’s Recommended Practices 752, 753, and 756, and other industry good practice guidance documents.
Using the results from the evaluation performed in 2025-03-I-PA-R1, ensure that all documented facility siting hazards are mitigated in accordance with the guiding principles contained in the American Petroleum Institute’s Recommended Practices 752, 753, and 756.
Develop a written procedure in accordance with industry guidance such as NFPA 56 Standard for Fire and Explosion Prevention During Cleaning and Purging of Flammable Gas Piping Systems, for washing valve seats with pressurized water. Ensure that the procedure includes steps and other controls, including overpressure protection, to minimize the hazards of the operation. Ensure that workers who will or might perform the operation are involved in the development of the procedure and are trained on the procedure.
Conduct a hazard analysis or safety validation of the written valve washing procedure in accordance with NFPA 56 Standard for Fire and Explosion Prevention During Cleaning and Purging of Flammable Gas Piping Systems. Ensure that workers who will or might perform the operation are involved in the analysis or validation.
Develop a comprehensive process safety management system, incorporating guidance from the Center for Chemical Process Safety’s Guidelines for Risk Based Process Safety and other industry good practice guidance publications, and apply it to all coke oven gas processes at the Clairton facility.