Combustible Dust - Are You at Risk?
Dust is more than a housekeeping issue. Dust can pose a fire hazard in the workplace, and many employers are unaware of this potential explosive situation.
What Is Combustible Dust?
Any combustible material, and some materials not normally considered combustible, can burn rapidly when in a finely divided, dust-like form. When suspended in air in the right concentration, especially in a confined or semi-confined vessel, area, or building, dust can become explosive. Add oxygen, and an ignition source is all that is needed for an explosion to occur. And one dust explosion can lead to more, if the first dust explosion in the processing equipment or vessel ruptures the enclosure and ignites nearby settled dust.
The force from such explosions can be deadly, and destroy entire buildings. In many combustible dust accidents, employers and workers were unaware that a hazard even existed.
Are You At Risk?
Some of the industries that could have a combustible dust hazard include:
- Agriculture, food--organic dust producers or users (e.g. working with fine dusts of candy, paper, pulp, soap, spices, starch, sugar, flour, and feed)
- Chemical, pharmaceuticals, plastics
- Forest and furniture products, wood pulp producers, paper products manufacturers
- Metal processing (e.g. aluminum, magnesium, zinc)
- Producers or users of coal or other carbon dusts
- Recycling operations (e.g. metal, paper, and plastic recycling operations)
- Tire and rubber
- Textile
- Wastewater treatment (biosolids)
According to the National Fire Protection Association, any industrial process that reduces materials to a finely divided state creates a potential for a serious fire or explosion. This holds true with both combustible and some normally noncombustible materials.
Be Proactive:
Conduct a Hazard Analysis:
- Recognize that you may have a combustible dust hazard.
- Look for processes that use, consume, or produce fine dusts.
- Look for accumulations of fine dust, including in hidden areas (such as inside ductwork or over suspended ceilings).
- Look for ways dusts can become dispersed in the air.
- Look for ignition sources.
- Consider dust collectors, hoppers, and other equipment that can confine a dust cloud.
- Investigate the thermal stability of stored products.
Control the Risk
- Prevent dust accumulations by frequent cleaning.
- Install special electrical equipment in areas with potential for explosive concentrations of combustible dust (Class II locations).
- Select and use industrial trucks properly.
- Implement proper procedures for the maintenance of ovens and process equipment.
- Install explosion relief venting devices.
- Design buildings, equipment, and ventilation systems properly (including bonding and grounding).
National Fire Protection Association (NFPA) Standards
Since neither OSHA nor Cal/OSHA has an integrated mandatory standard that covers combustible dust, employers must rely on the various NFPA standards for guidance which can be accessed at http://www.nfpa.org/.
Additional Information
- Contact your nearest regional office for information and assistance on combustible dust and many other safety services available.
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