Overview
- Filed in Allegheny County by Trisha Lynn Quinn, the complaint follows the Aug. 11, 2025 explosion that killed Timothy Quinn and Steven Menefee.
- The lawsuit names Nippon Steel, MPW Industrial Services, and Valves Inc., alleging negligence after Nippon completed its purchase of U.S. Steel in June 2025.
- The filing alleges contractors used high‑pressure water instead of steam, overpressurizing an aging isolation valve that cracked and leaked coke oven gas.
- OSHA this week issued 10 citations and proposed more than $118,000 in penalties to U.S. Steel, faulting incomplete procedures and training tied to the valve work.
- The complaint also highlights prior siting warnings and building placement over hazard piping, while Valves Inc. says it has not worked on the valve in over 12 years as the CSB probe continues.