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The flash fire that burned seven workers, one seriously, in 2012 resulted from the accumulation of combustible dust inside a poorly designed dust collection system that had been put into operation only four days before the accident. The CSB investigation team concludes that the system was so flawed it only took a day to accumulate enough combustible dust and hydrocarbons in the duct work to overheat, ignite spontaneously, cause an explosion in the rooftop dust collector, and send back a fiery flash that enveloped seven workers. The CSB found that the ductwork conveyed combustible, condensable vapors above each of three tanks in the mixing room, combining with combustible particles of dust of carbon black and Gilsonite used in the production of black ink. The closed system air flow was insufficient to keep dust and sludge from accumulating inside the air ducts. But to make matters worse, the new dust collector design included three vacuuming hoses which were attached to the closed-system ductwork, used to pick up accumulated dust, dirt and other material from the facility’s floor and other level surfaces as a ‘housekeeping’ measure. The addition of these contaminants to the system ductwork doomed it to be plugged within days of startup. The report describes a dramatic series of events that took place within minutes on October 9, 2012...
UPDATE on 7/21/14 - The Jan. 20 structural collapse was caused by overloading nine storage bins on the building's roof level, an OSHA investigation has found. The collapse at the livestock feed supplement manufacturer caused the death of two workers and injuries to nine others. The investigation determined a structural failure of the east side truss, after bins that it supported were loaded with an excess of limestone. The extra weight caused the bins to collapse three floors into the center of the facility in about 30 seconds. As a result of the tragic incident, OSHA has cited the company with one willful, one repeat and 11 additional safety violations for failing to protect workers from hazards associated with structural collapse. https://www.osha.gov/pls/oshaweb/owadisp.show_document?p_table=NEWS_RELEASES&p_id=26418
CLICK HERE for the citations
As end-of-summer harvest time nears, grain storage facilities will be gearing up to accept crops from farmers’ fields. Many of these products produce combustible dusts that can result in catastrophic explosions when there is a suitable mix of air and fuel, as well as an ignition source such as a hot bearing, overheated motor, misaligned conveyor belt, or when welding, cutting and brazing are taking place.
According to U.S. Department of Labor statistics, since 1976, there have been 503 grain elevator explosions in the United States, resulting in 184 deaths and 677 injuries. The likelihood, severity and lethality of grain dust explosions and fires can be reduced by a few simple safety precautions.
Today in Omaha, NE there was an industrial accident at a business where one would expect to find combustible dusts. The accident resulted in several employees being treated for burns and there are two confirmed fatalities as of this evening. And although, we were quick to point out this accident may have involved a combustible dust explosion I now believe that the collapse of the structure was the initiating event and any fires and explosions were secondary to the collapse. Bear in mind this is a THEORY based solely on photographic evidence from OUTSIDE the facility; however, these photographs provide very strong evidence to back up my theory. Using my cause and origin investigation skills from way back in the day I can see (and NOT see) the following using the aerial photos provided by the Omaha Herald (http://odc.omaha.com/index.php?u_page=5002&p=5039)
This document is the Preliminary First Draft of the proposed 2015 edition of NFPA 652. The standard will provide the basic principles of and requirements for identifying and managing the fire and explosion hazards of combustible dusts and particulate solids. The standard will provide the user with general requirements and direct the user to the appropriate industry or commodity-specific NFPA standard for additional requirements. It establishes the basic principles and requirements that shall be applied to all facilities where combustible dusts or particulate solids are present. Where an industry or commodity-specific NFPA standard exists, its requirements shall be applied in addition to those in this standard. CLICK HERE to see the first draft.