U.S. Steel Corp. faces $118,214 in Occupational Safety and Health Administration (OSHA) fines for seven serious violations and one other-than-serious violation related to an explosion at its Clairton Coke Works plant last August, the agency announced Feb. 18.
OSHA investigators concluded that U.S. Steel and MPW Industrial Services Inc., the cleaning services contractor, exposed workers at the Clairton Coke Works to unsafe working conditions, including explosion, struck-by, and high-pressure injection hazards. They determined U.S. Steel failed to use required safety management and energy control practices for hazardous work involving flammable gas. OSHA also concluded that MPW Industrial Services failed to provide a relief valve for a high-pressure water system and didn’t coordinate energy control practices for hazardous work involving flammable gas.
The agency cited MPW Industrial Services with four serious and two other-than-serious violations, and the company faces $61,473 in OSHA penalties.
Both employers have 15 business days from receipt of their citations and penalties to comply, request an informal conference with OSHA, or contest the findings before the independent Occupational Safety and Health Review Commission.
The U.S. Chemical Safety and Hazard Investigation Board (CSB) is also investigating the Aug. 11, 2025, fatal explosion at U.S. Steel’s Clairton Coke Works and issued two interim safety recommendations.
The CSB has so far determined that the explosion occurred when coke oven gas released from process piping in the Battery 13/14 transfer area at the facility was ignited.
Two U.S. Steel employees were killed in the explosion, four additional employees and a contractor were seriously injured, and six other workers suffered injuries that didn’t require hospitalization.
The board recommended that U.S. Steel conduct a thorough evaluation of all buildings at the facility that are currently occupied or could be occupied to identify and assess potential worker hazards based on their locations. It also recommended that the company address and reduce any safety risks identified in the facility siting evaluation in accordance with accepted industry safety principles.
The CSB is an independent federal government board that investigates industrial chemical incidents. Unlike OSHA, it doesn’t issue citations for regulatory violations or impose fines; instead, it makes safety recommendations to companies, industry groups, labor unions, and regulatory agencies, including OSHA and the Environmental Protection Agency (EPA).