What is Combustible Dust?
According to NFPA 654, “As little as 1/32 of an inch of organic dust over 5 percent of a room’s surface area presents a significant explosion hazard.” Many substances can become explosive when in fine dust form. Grains, wood, coal, plastics, foams, pharmaceuticals, and certain metals (i.e. aluminum, zinc, iron, and magnesium) may become combustible. If these substances, or others like them, are in a concentrated cloud with an oxidizing medium, and there is a possible ignition source, there is a high risk of explosion. The possibility for explosions can be reduced by the removal of fine dust as it accumulates.
combustible materials
Below is a list of substances that have the potential to produce combustible dusts and are likely to cause dust deflagrations, other fires, or explosions. These include, but are not limited to:
- Metal dust such as aluminum and magnesium.
- Wood dust
- Coal and other carbon dusts
- Plastic dust and additives
- Biosolids
- Other organic dust such as sugar, flour, paper, soap, and dried blood.
- Certain textile materials
Industries
OSHA Standard Industries that handle combustible dusts include, but are not limited to:
- Agriculture
- Food Products
- Chemicals
- Textiles
- Forest and furniture products
- Metal processing
- Tire and rubber manufacturing plants
- Paper products
- Pharmaceuticals
- Wastewater treatment
- Recycling operations (metal, paper, and plastic.)
- Coal dust in coal handling and processing facilities
(Note: OSHA Standard 29 CFR 1910.269(v)(11)(xii) addresses control of ignition sources at coal handling operations in electric power plants. The Mine Safety and Health Administration (MSHA) has authority in some areas involving coal crushing and conveying. See OSHA Instruction CPL 02-01-038 dated June 18, 2003 for additional guidance on authority)
