From Woodworking Network:

..While OSHA currently does not yet have a formal combustible dust standard, that is NOT preventing OSHA inspectors from issuing citations related to combustible dust using current regulations.

The first citation from this particular inspection states, “layers of combustible wood dust were allowed to accumulate to depths over surface areas in quantities that exposed workers to fire and or explosion hazards.”  This citation references 29 CFR 1910.22(a)(1)…So the layers of wood dust in this citation were in direct violation of the current “housekeeping” regulation.

The second citation is also worthy of exploration.  In this case the “general duty clause” is cited… The general duty clause is basically an all-encompassing regulation that OSHA uses if there is a perceived violation that is NOT covered by any other regulation.

..As of this date there is no formal timeline for a standard but combustible dust is still in the rulemaking process.

OSHA did, however, issue a modification of the Hazardous Communication Standard in March (2012) to include Combustible Dust as a hazardous chemical. By doing so, OSHA’s has expanded the depth of its ability to using more detailed sections of the CFR in citing combustible dust violations. The biggest issue is the lack of a definition for combustible dust.  There is, however, now a clearly defined standard that requires “labeling” under the newly defined GHS (Globally Harmonized System) because combustible dust hazards “may form combustible dust concentrations in the air.”

For the full story see the above link.