By: Patricia A. Mason, P.E.
This week a dust explosion at a grain handling plant in Flagstaff, Arizona injured four American workers. This follows last month’s explosion at a car parts factory in China which killed 75 people. The hazards of combustible dust continue to be a serious threat and continue to be poorly understood by many. Combustible dust explosion hazards exist in a variety of industries including:
- Agriculture (e.g., grain, tobacco)
- wood (forest, paper, and pulp)
- foods (e.g., candy, sugar, spice, starch, flour, feed),
- dyes,
- textiles,
- furniture,
- chemicals,
- fertilizer,
- pesticides,
- plastics,
- pharmaceuticals,
- tire and rubber manufacturing,
- coal and fossil fuel power generation,
- metal processing (e.g., aluminum, chromium, iron, magnesium, and zinc), and
- recycling operations.
Many variables – the type and particle size of the dust, the method of dispersion, ventilation system modes, air currents, physical barriers, and the volume of the area affect the risk for explosion. Rules of thumb regarding dust accumulation can be subjective and misleading. There are, however, many steps which can be taken to prevent dust explosions. Understanding the hazards at a facility is critical. A hazard analysis should be tailored to the specific circumstances in each facility and the range of variables affecting the hazard. Dust control recommendations have been developed including inspection, testing, housekeeping, and dust minimization programs. For more information refer to OSHA’s combustible dust web area for general information, guidance, standards and many other resources. Additionally, the Kentucky Department of Labor has a Hazard Alert for combustible dust. Education, planning and diligence in implementing controls are needed to prevent catastrophic events at susceptible facilities.