CHARLESTON - The U.S. Chemical Safety Board's report on the December 2010 fatal explosion at AL Solutions' New Cumberland plant, which killed three workers, contains both findings and recommendations.
The key findings:
The explosion in the production building was caused by combustible titanium and zirconium dusts that were processed at the facility.
The explosion likely originated in a blender containing milled zirconium particulates and ignited by frictional heating or spark ignition of the zirconium arising from defective blender equipment.
The hydrogen gas produced by the reaction of molten titanium or zirconium metal and water, possibly from wash-down operations or the water deluge system, may have also contributed to the explosion.
Testing conducted after the incident determined that zirconium and titanium samples collected from the AL Solutions facility were combustible and were capable of causing an explosion when lofted near heat or an ignition source.
AL Solutions did not mitigate the hazards of metal dust explosions through engineering controls, such as a dust collection system. Specifically, AL Solutions did not adhere to the practices recommended in NFPA 484 for controlling combustible metal dust hazards.
The West Virginia area office of OSHA did not conduct a combustible dust NEP (National Emphasis Program) inspection at AL Solutions before the 2010 incident, despite the company's history of metal dust incidents.
The recommendations to AL Solutions Inc.:
For all new and existing equipment and operations at AL Solutions facilities that process combustible metal dusts or powders, apply the National Fire Protection Association's "Standard for Combustible Metals," chapters 12, 13, 15 and 16.
Develop training materials that address combustible dust hazards and plant-specific metal dust hazards and then train all employees and contractors.
The recommendations for AL Solutions' new facility in Burgettstown, Pa.:
Prohibit the use of sprinkler systems and water deluge systems in all buildings that process or store combustible metals.
Conduct a process hazard analysis, as defined in NFPA 484, and submit a copy to the local fire department or the enforcing authority for the fire code.