With its order for B.C. mills to clear up airborne dust that could ignite, Worksafe BC is tackling an ongoing problem in sectors other than forestry.
Even though airborne sawdust has not been determined as the cause of either the January sawmill explosion in Burns Lake or the fire in Prince George on Monday that destroyed Lakeland sawmill, Worksafe BC has issued the cleanup order across the province.
Mills of all sorts have exploded due to dusty air, dating back centuries. A recent graphic example was the 2008 fire that blew up and burned the 180-year-old Hayhoe Flour Mill in Ontario when flour dust ignited.
The television show Mythbusters did a segment verifying that flour-fine dust in the air was in fact highly explosive by setting off a flour cloud bomb.
The Department of Grain Science and Industry at Kansas State University studied the issue in 1994 and calculated an average of 10 grain elevators/flour mills were exploding in the United States each year. They studied it again in 1997 and found 16 agricultural dust explosions that year alone.
When the mountain pine beetle epidemic killed vast swaths of forests that were still being milled, said Worksafe BC spokesperson Donna Freeman, everyone in the mill industry was aware that the tree was dry on the stem when it arrived at the mill.
"Pine beetle dust is distinct - it is finer and drier and this has been known since they began milling it," she said.
Simple equipment is available to mills to measure the dust inside their facilities, Freeman said.
"This would be a normal part of an inspection in any sawmill [but it is not] just about the airborne concentrations but also accumulated dust that could become airborne through sudden air current changes, vibration or improper cleaning procedures in the presence of an ignition source," she added.
