Following the catastrophic explosions in Burns Lake and Prince George earlier this year, WorkSafeBC committed to industry that it would share pertinent information that emerged during the course of the investigations.
Since these tragic events, there has been speculation on the role of beetle-kill wood as the potential fuel source. In the course of the investigations, WorkSafeBC collected green wood dust samples and submitted them to a US laboratory along with beetle-kill samples for purposes of comparison.
WorkSafeBC has recently received laboratory test results that conclude that both beetle-kill and green wood* dust pose a high risk of explosion when the moisture content of the dust is below 5 percent and particle size is less than 75 μm (micrometers)**. Dust with this moisture content and particle size is found on elevated surfaces such as rafters, beams, inside dust collectors, and on the surface of air separation systems as well as in hot dry environments such as process equipment and light covers.
Direction has previously been issued to industry regarding the importance of rigorous dust management procedures and WorkSafeBC is currently engaged in a multi-phase inspectional program. Phase 1 saw the inspection of all sawmills in the province processing either green or beetle-kill wood. Phase II, which began in July, expanded the inspectional program to include other wood processing operations such as pellet and planer mills where dust accumulation could be a safety hazard. Phase III will expand to industries that generate dust from wood and other sources; this would include workplaces that manufacture rubber, aluminum and sugar, for example.
WorkSafeBC is releasing the lab results to ensure that employers who may be using green wood are well advised and understand the need for continued rigour in their workplaces to ensure that mills are cleaned and dust is not permitted to accumulate. This information is being shared as a matter of general concern and advice to industry and does not reflect conclusions in the two on-going investigations.
In a previous advisory on May 2nd, 2012 WorkSafeBC released an investigation update on the Babine Forest Products explosion that spoke to potential fuel and ignition sources — those ruled out at the time and those still under consideration. Sawdust was identified as a potential fuel source and remains under investigation.
Later on May 14th, 2012 industry was provided with further information regarding ignition sources common to both investigations that were located at the conveyor level, where electrical and/or mechanical equipment was in operation in areas contained by walls and equipment.
More information and updates on the sawmill inspection initiative is available on www.worksafebc.com.
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