Seems like a week doesn't go by that one doesn't hear about another facility exploding or catching on fire due to flammable liquids, gases, or vapors. Since 2003 the Chemical Safety Board has investigated nearly two dozen of these incidents. Now with this recent incident hitting the news wire, CSB will also investigate another refinery fire in Salt Lake City. So is it time now for a separate OSHA Flammable Liquid, Gas, and Vapor Regulation next? After all, a separate OSHA combustible dust regulation is in the works.
Potentially explosive concentrations of gas, vapor or mist in the air, also includes concentrations of dust in the air. Amazingly, the explosive effects are all the same with overpressure, thermal radiation, and ensuing projectiles. In fact a vapor cloud explosion is a propagating explosion like a dust explosion, where there is a pressure wave and flame/reaction front in both. The main difference between vapors and combustible dust is a lower ignition sensitivity (MIE) with vapors.
No I guess it wouldn't make sense to have a separate OSHA Flammable Liquid, Gas, and Vapor Regulation. That makes as much sense as having a separate OSHA combustible dust regulation. What needs to be done instead is for all stakeholders to acknowledge that combustible dust is a potentially explosive atmosphere like all the rest. A separate dust regulation only further deviates from the issue that what we got here is one nasty hombre that needs the same respect as all the other explosive atmospheres. Check out elements of the ATEX directive from our global trading partners in the EU to get an idea of how the wheel does not need to be reinvented.
Dust ANPRM -Physical Properties
Acknowledging combustible dust as a potentially explosive atmosphere will go a long way in fixing the broken OSHA HazCom standard. The recent combustible dust ANPRM did not even mention the physical properties aspect that CSB found was deficient in the 140 MSDS's they surveyed in the 2006 Dust Hazard Study. It's like how would the raw product manufacturer of milk have any idea that his product had inherent explosive severity and ignition sensitivity characteristics? Midstream in the life-cycle at the milk powder plant with the spray dryers is an entirely different situation.
We all have heard it, in all the recent press releases over the past 20 months that a separate dust regulation will prevent dust explosions. Well of course if you shut down the entire manufacturing sector you would prevent primary explosions. But its not the primary explosions that resulted in the catastrophic events of Imperial Sugar and the devastating toll of the three dust explosions in 2003. It was the secondary explosions fueled by poor housekeeping. Simply remove the fuel load and you won't have a secondary dust explosion. In contrast, primary dust explosions will never be totally prevented, only the severity and probability reduced with appropiate layers of protection.
Last year there was over 150 combustible dust related fires and explosions in the manufactruing, non-manufacturing, and utility sectors. Not counting Imperial Sugar, the human toll was minimal in comparison to any other industry. Any fatality or injury is one too many. Yet, the severity of injuries would of even been less if the workers had donned flame resistant clothing. Over 80% of the incidents in 2008 were combustible dust related fires not explosions. Most incidents barely get notice in the news because thankfully there's no fatalities or injuries, only minor economic damage to the facility.
All combustible dust related fires and explosions need to be addressed in the realm of occupational health and safety. Already dusts are mentioned in several OSHA general industry regulations. So lets stop fooling around and get the specific wording "combustible dust" in the rest if the OSHA general industry regulations like is done with flammable liquids, gases, and vapors.
Failure to Communicate
It's frustrating to see all the mention of the issue solely on the process materials (dust). What about process conditions and process situations? You can't be identifying, evaluating, and controlling the hazard without recognizing the entire triad. Sort of reminds me of the scene in the 1967 movie, "Cool Hand Luke," when the Captain tells Luke, ""What we've got here is...failure to communicate." In this case of dust, there is a need to communicate the entire risk in the national policy making dialogue.
The issue of combustible dust incidents is a process situation where a majority of facilities have similiar processes that include bulk storage, material transfer, pnuematic conveying, duct systems, pressure relief devices, material feeding devices, belts, drives, conveyors, air material separators, mixers/blenders, dryers, etc. The only difference is the type of process materials (dust) spread out over 400 national industries in the industrial sector. A Hybrid Process Safety Management (PSM) standard for combustible dust is in order. Why keep trying to reinvent the wheel when a majority of PSM elements already are incorporated in the National Fire Protection Association combustible dust standards?
But again why not? Maybe a separate OSHA Flammable Liquid, Gas, and Vapor Regulation and another separate OSHA combustible dust regulation makes more sense. Just my two cents.