By: Tyler Levenson
The Occupational Safety and Health Administration (“OSHA”) appears ready to pass on regulations regarding combustible dust, a dangerous and poorly regulated workplace hazard. OSHA currently has a very busy agenda for the upcoming year. Moreover, regulations involving combustible dust are riddled with complicated issues and complex scientific evaluations. These two factors combined have caused OSHA to likely leave combustible dust regulations off of its 2016 agenda.
Combustible dust is defined as “a solid material composed of distinct particles or pieces, regardless of size, shape, or chemical composition, which presents a fire or deflagration hazard when suspended in air or some other oxidizing medium over a range of concentrations.” Combustible dust particles are commonly either organic or metal dusts, finely ground into small particles, fibers, fines, chips, chunks, flakes, or a combination of all six. Five conditions must be met in order to have an explosion. An explosion requires the commonly known fire triangle, i.e. oxygen, heat, and fuel (dust in this case), as well as dispersion of dust particles in sufficient quantities and concentrations, and confinement. Confinement commonly refers to dust that is highly concentrated in buildings, rooms, vessels, or process equipment. Confinement of the dust particles is the key element, as it results in an increase in pressure, which may cause an explosion. These five elements have been nicknamed the “Dust Explosion Pentagon.” In order to have an explosion at all, all five elements must be met.
Combustible dust explosions are most prevalent in industries including “agriculture, chemicals, foods, grain, fertilizer, tobacco, plastics, wood, forest, paper, pulp, rubber, furniture, textiles, pesticides, pharmaceuticals, tire and rubber manufacturing, dyes, coal, metal processing, recycling operations, fossil fuel power generation, and 3D welding.” Explosions are a constant threat to the workers in these industries. The U.S. chemical Safety and Hazard Investigation Board has identified 281 combustible dust explosions between 1980 and 2005. These incidents have led to 119 worker deaths, 718 injured workers, and damage and destruction to numerous industry facilities.
Examples of lethal explosions include an incident in Massachusetts in the February of 1999. The location of the incident was a foundry. A joint investigation conducted by OSHA and state and local officials revealed the fire started in a “shell molding machine from an unknown source and then extended into the ventilation system ducts by feeding on heavy deposits of phenol formaldehyde resin dust.” This first explosion dislodged dust that had settled on the exterior of the ventilation duct. This newly dislodged dust provided the fuel for a secondary explosion which was powerful enough to remove the roof and cause wall failure throughout the facility. This explosion resulted in the deaths of 3 workers and injuries to 9 more. Another explosion in 2003 in Kentucky resulted in the deaths of 7 workers and injuries to 37 others. The investigations following the explosion revealed the cause to be a fire that started in an unattended oven which ignited a large dust cloud created by nearby line cleaning. This first explosion triggered a chain reaction of secondary explosions throughout the facility. A more recent example from February 7, 2008, saw an explosion in a Georgia sugar refinery take the lives of 14 workers and leave many others severely injured with burns and other afflictions.
Different dusts or the same chemical materials will exhibit different explosive properties, depending on many variables, including particle size, shape, concentration, etc. Because there are so many variables involved in a dust explosion, it is extremely complicated to set just one standard for combustible dusts. For now OSHA has published recommended guidelines for dust and ignition control, as well as required training programs for certain types of employees. OSHA believes that workers are the first line of defense in protecting themselves from these dangerous explosions, and for now that is how it will remain as no new regulations are expected to be enacted any time soon.
 Occupational Safety and Health Administration, https://www.osha.gov/Publications/3371combustible-dust.html (last visited Jan. 24, 2016).
 Occupational Safety and Health Administration, https://www.osha.gov/OshDoc/data_General_Facts/OSHAcombustibledust.pdf (last visited Jan. 24, 2016).
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