Canadian Occupational Safety

20 Canadian Occupational Safety www.cos-mag.com its investigation into an explosion at Babine Forest Products sawmill in Burns Lake, B.C., in January 2012. The investigation determined the cause of the explosion, which killed two work- ers and injured 20, was accumulation of wood dust. Three months later, a wood dust explosion destroyed the Lakeland Mills sawmill in Prince George, B.C., killing two workers and injuring 22 others. "When I look at combustible dust in a workplace, I see sticks of dynamite waiting for their fuses to be lit," says Raymond Roch, director at the Fire Inspection and Prevention Initiative (FIPI) in Richmond, B.C. The hazard of combustible dust affects many industries, he says. Most combustible dust incidents occur in wood product companies, but they also happen in industries such as food (egg whites, powdered milk, cornstarch, sugar, flour, grain), metals A large fireball burst through the roof at the northeast side of the mill. The explo- sion then travelled through the operating and basement levels. Fire spread throughout the prem- ises, completely destroying the mill. This is how WorkSafeBC described (iron, aluminum, zinc, magnesium), chemicals (sulphur, pesticides), phar- maceutical, pulp and paper, minerals (coal), utilities, plastics, rubber, print- ing and textiles. Dust is combustible when it is flam- mable or explosive. The fast-burning fire produced in a dust cloud is often called a deflagration. For an explo- sion to happen, five elements must be present: • fuel (combustible dust) • oxygen • ignition source (a flame, hot surfaces, sparks from electrical equipment or static electricity) • dispersion (or cloud) of dust particles • containment of the dust cloud. Sometimes, there is a series of explosions. The pressure wave created by the first explosion knocks dust off rafters and beams, which then becomes airborne. The fireball from the explosion then lights that dust and causes a secondary explosion, which can dislodge more secondary (or fine) dust and cause another explosion. "So you get this domino effect," says Roch. "That's why you get entire facilities blown up: It wasn't one explosion." If a company is producing dust, the first thing to do is determine whether the dust is combustible. Michelle Murphy, a partner at ioKinetic in Salem, N.H., says every company with dust should get it tested. "There are some things we know for sure, but they are few. (We know) sand and salt are not combustible. But for the majority of materials, it's very difficult to tell," she says. "So, if you believe it's not combustible, a quick screening test is a good way to By Linda Johnson No longer just for winter sports... Outdoor workers have discovered "HEAT" Instant warmth! Just open the package and shake... Your workers will be more comfortable and, therefore, more productive. Hours and hours of heat and will fit almost anywhere (pockets, gloves, hats & winter headliners). Variety of apparel available including: • Hand - Pop Top Mitt with glove liner. • Head - Balaclavas and hard hat liners. • Feet & Toes - Pocket Sock. • Survival warmers for emergencies. • Up to 18 hours of warmth for your workers. Contact us for a FREE sample or visit our website! 1-888-533-6832 www.dentecsafety.com Training Support Balaclava with warmer Bodywarmers by Specializing in safety solutions Dentec - Hot Hands Ad 3.325" x 4.875" - ENG.indd 1 9/28/12 2:56 PM Don't slip... just flip... Flip up to drive or enter a building and flip down to walk on slippery surfaces - it's so easy and safe! • Ideal for delivery personnel • Perfect for indoor/ outdoor use • Won't interfere with driving • Fits a wide variety of footwear Specializing in safety solutions Training Support Contact us to see if you qualify for a FREE sample or visit our web site: http://www.dentecsafety.com/campaign.htm 1-888-533-6832 With duenorth's new HTA (Heel Traction Aid) DENTEC - HTA.indd 1 8/15/12 11:23 AM DusT TesTing, collecTion sysTems cAn pRevenT an explosion SET When the

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