According to OSHA,
A wide variety of materials that can be explosible in dust form exist in many industries. Some industry examples include: food (e.g., candy, sugar, spice, starch, flour, feed), grain, tobacco, plastics, wood, paper, pulp, rubber, furniture, textiles, pesticides, pharmaceuticals, dyes, coal, metals (e.g., aluminum, chromium, iron, magnesium, and zinc), and fossil-fuel power generation.
Any combustible material can cause flash fire and dusts are no exclusion. Solid materials in a finely divided form can burn rapidly. In addition to flash fire, under certain conditions dust can become explosive if it is suspended in air. Even materials that do not burn in larger pieces can be explosive in dust form. The force from an explosion can result in personnel deaths, burn injuries, and destruction.
Spring 2013: OSHA began rulemaking to develop a combustible dust standard for general industry. See the latest updates here.
While the final standard from OSHA is not yet complete, employers should consider the OSHA general duty clause. If a hazard is not addressed by an OSHA standard, Section 5(a)(1) of the OSH Act, the General Duty Clause may apply.