OccuSafe Industrial Hygiene Consulting

A combustible dust is any material (finely divided solid particles) that has the ability to disperse in air and catch fire and explode when exposed to an ignition source. Combustible dust may include materials that are in the physical states of powders, flakes, fines, fibers, etc. Examples include:

• metal dust such as aluminum, magnesium and some forms of iron dusts 
• wood dust 
• coal and other carbon dusts, including carbon black 
• plastic dust, phenolic resins, and additives 
• rubber dust 
• biosolids 
• other organic dust, such as sugar, flour, paper, soap, and dried blood 
• certain textile materials 

Although not directly related to industrial hygiene, industrial hygienists and safety professionals are likely be involved in inspections, follow-up, and evaluation of combustible dust hazards. Industrial hygienists can conduct air monitoring to determine the concentration of particulates in the air. They can also help design ventilation systems to better control dust.

OSHA does not have a specific standard for combustible dust but there are other resources that can be helpful in evaluating dust hazards:

• NFPA 654: Standard for the Prevention of Fire and Dust Explosions from the Manufacturing Processing and Handling of Combustible Particulate Solids.
• The US Chemical Safety Board has conducted combustible dust hazard investigations and made recommendations.
• GESTIS-DUST-EX Database Combustion and explosion characteristics of dusts. It is a European data base that contains important combustion and explosion characteristics of more than 7,000 dust samples from virtually all sectors of industry that were determined as a basis for the safe handling of combustible dusts and for the planning of preventive and protective measures against dust explosions in dust-generating and processing plants.

OSHA does have some resources that may be helpful in evaluating dust hazards. In addition, it has had a National Emphasis program since 2008 and recently updated its list of industries that may be susceptible to dust hazards. In some instances, OSHA has cited employers under the General Requirements 1910.22 standard.

Each year there are industrial combustible dust incidents and explosions. Some have caused serious injury and death. It is important that management identifies combustible dusts in their operations, use available resources, and limit the accumulation of dust in their facilities.