Here is an example reported by OSHA where combustible particulate solids were not collected into an adequately designed dust collection system.

OSHA reminds us that “An effective dust collection system, proper industrial hygiene and frequent cleaning are critical to preventing a dangerous and potentially fatal buildup of combustible dust in the workplace.”

US Labor Department’s OSHA proposed $90,500 in fines against the concerned company for fire and explosion hazards.

See the OSHA citation for combustible dust fire and explosion hazards:

https://www.osha.gov/pls/oshaweb/owadisp.show_document?p_table=NEWS_RELEASES&p_id=17106