According to OSHA, combustible material can burn rapidly when in a finely divided form. If such a dust is suspended in air in the right concentration, under certain conditions, it can become explosive. Even materials that do not burn in larger pieces, given the proper conditions, can explode in dust form.
There is no OSHA standard on combustible dust, but under the
Combustible Dust National Emphasis Program,
OSHA can issue fines for violations under 18 different standards, including 1910.22, the main umbrella standard. You can also be cited under the General Duty Clause, which can apply to recognized hazards not specifically addressed in OSHA standards.
NFPA developed a
to promote awareness of combustible dust hazards. The standard was created to promote and define hazard analysis, awareness, management and mitigation. It helps in identifying combustible dust hazards and what to do about them.
NFPA 652 requires all facilities that process, handle, convey, or manufacture potentially combustible dust to have their dust tested and keep the results on file. This is required, NFPA says, even if your type of dust has no history of causing an incident.
The vast majority of natural and synthetic organic materials, as well as some metals, can form combustible dust. NFPA's "Industrial Fire Hazards Handbook" states that "any industrial process that reduces a combustible material and some normally noncombustible materials to a finely divided state presents a potential for a serious fire or explosion."