Dust Explosions Remain a Risk for Some Pharma Operations

Several years ago, we scheduled an article on avoiding dust explosions.  The expert contributor assigned to write the article laughed at the premise that such things could even occur, given the rigorous safety and other standards in place. And the idea of such an explosion taking place at a Pfizer or Lilly plant today does seem laughable. Yet, explosions have occurred at smaller facilities, particularly those that handle compounding,  and they may continue to take place if operators overlook key safety requirements.  This week,  the U.S. Chemical Safety Board released its latest report on avoiding dust explosions, including results of a study of the tragic 2003 West Pharma incident (excerpt below). For more information visit the Board's web site. 4.2.1 West Pharmaceutical Services, Inc. On January 29, 2003, a massive dust explosion at the West Pharmaceutical Services facility in Kinston, North Carolina, killed six workers and destroyed the facility. The explosion involved a part of the building used to compound rubber. West produced rubber syringe plungers and other pharmaceutical devices at the facility. In the rubber compounding process, freshly milled rubber strips were dipped into a slurry of polyethylene, water, and surfactant to cool the rubber and provide an anti-tack coating. As the rubber dried, fine polyethylene powder drifted on air currents to the space above a suspended ceiling. Polyethylene powder accumulated on surfaces above the suspended ceiling, providing fuel for a devastating secondary explosion. While the visible production areas were kept extremely clean, few employees were aware of the dust accumulation hidden above the suspended ceiling, and the MSDS for the polyethylene slurry included no dust explosion warning. Even those employees who were aware of the dust accumulation had not been trained about the hazards of combustible dust. West did use a safety review process when the compounding system was designed and modified, but the dust explosion hazard was not addressed during the reviews. OSHA, the local fire department, an insurance underwriter, and an industrial hygienist had inspected the facility, but none had identified the potential for a dust explosion. In addition, the electrical equipment above the suspended ceiling in the rubber compounding section was not rated for use around combustible dust, as the National Electric Code (NEC) requires (for areas where combustible dust can accumulate). The CSB determined that if West had adhered to NFPA standards for combustible dust, the explosion could have been prevented or minimized.