Overview
- A final Chemical Safety Board report found the blast that killed two workers and injured 11 at U.S. Steel’s Clairton Coke Works was preventable and traced the immediate cause to a catastrophic valve failure.
- Investigators concluded contractors applied pressurized water to a closed or nearly closed double-gate valve, overpressurizing a brittle cast-iron valve more than 70 years old and releasing flammable coke oven gas that ignited and exploded.
- The CSB faulted U.S. Steel for lacking a written procedure for the valve-cleaning practice and for an ineffective process-safety management system that let an informal, risky method continue for years.
- U.S. Steel said it will review the CSB recommendations and has already implemented standardized valve-cleaning practices, improved management-of-change processes and expanded worker training.
- The report urges evaluating building siting that placed control rooms and a break room above hazardous piping and could prompt regulatory or enforcement actions and wider industry changes to prevent future deaths from similar failures.