November 9, 2010 explosion at an E.I. duPont de Nemours and Co. Inc., Yerkes chemical plant in Buffalo, New York when a contract welder and foreman were repairing the agitator support atop an atmospheric storage tank containing flammable vinyl fluoride. The welder died instantly from blunt force trauma, and the foreman received first-degree burns and minor injuries. The explosion blew most of the top off the tank. The top and agitator assembly hung over the side of the tank supported only by a 2-foot section of the top (cover photo). The explosion caused minor overpressure damage in the tank farm area and the adjacent production building.

KEY ISSUES:
• FLAMMABLE GAS MONITORING
• TANK ISOLATION
• HOT WORK PERMITS, PROCEDURES & SIGN-OFFS

ROOT CAUSES:
1. All potential explosion hazards associated with hot work activities not identified and mitigated
2. All relevant forms required for permits not completed in accordance with corporate policies and industry standards (including NFPA 326 and NFPA 51B)
3. Appropriate DuPont personnel did not officially approve hot work permits, by signature or equivalent, consistent with DuPont policies

Image credit: CSB