A combustible dust explosion occurred at a pharmaceutical preparation plant in Iowa prior to the end of the 2010 a few weeks ago. Luckily there were no injuries or fatalities and damage was minor according to the news account.
"There were no injuries. The explosion blew out doors on the building and dust collectors, with additional minor damage."Eastern Iowa News Now
It appears the mention of doors blowing out in the dust collector might be referring to explosion ventilation panels. Being that the plant is involved in pharmaceutical preparation with a NAICS 325412, it is noted in the OSHA Combustible Dust NEP in Appendix D-1 as an Industries with More Frequent and/or High Consequence Combustible Dust Explosions/Fires.
Over the past 12 months OSHA has been enforcing a myriad of regulations in addition to ComDust NEP emphasis in their site visits at pharmaceutical preparation facilities. The OSHA Integrated Management Information System also referred to as IMIS provides a helpful insight to these inspections.
An educational General Duty Clause citation for one Pharmaceutical Preparation Plant noted that "neither dust collector was equipped with deflagration venting panels directed to an unoccupied area or with a suppression system. The collectors were located inside an occupied area which employees entered to conduct maintenance on a daily basis."This is in contrast to the current incident where the dust collector was installed outside on the roof and appeared to have explosion vent panels.
Results of an internet search produced a MSDS for microcrystalline cellulose (MCC) Cellulose; flour cellulose which has combustible dust fire explosion hazards. For example in the Fire Fighting section it notes, "Fine dust dispersed in air in sufficient concentrations, and in the presence of an ignition source is a potential dust explosion hazard. For Cellulose: Minimum ignition temperature, dust cloud: 410C. Minimum explosible concentration: 0.045 g/l." This is helpful information so stakeholders can take proper administrative, PPE, and engineering control measures.
On a side note, another combustible dust related fire and explosion originated from the same company that occurred nearly two weeks prior to above incident, yet paper dust was the process material at a different facility instead of microcrystalline cellulose (MCC) according to the news account.
“Something caused the paper dust to explode. We don’t know what it was,” Battalion Chief Rick Palmer of the Portage Fire Department said. Palmer said the fire department has been called to explosions at the plant in the past, most recently about eight months ago. Small fires can develop wherever the dust settles in the plant following such an explosion, he said. “We just chase little fires all over the place,”Michigan Live.com
Stakeholders searching the OSHA Combustible Dust NEP will not find any paper industries that OSHA believes have More Frequent and/or High Consequence Combustible Dust Explosions/Fires or Potential for Combustible Dust Explosions/Fires. Don't know what the NAICS is for the facility that generated paper dust in the news account yet there is mention that the facility produces paper insulation. In either case whether or not a facility is listed in the OSHA ComDust NEP, if you generate ComDust then you need to identify, evaluate, and control the fire and explosion hazards.