Dust explosions in Canadian sawmills

A little more background is given here to the story briefly reported in the May INSIDER Newsletter, about the action taken by WorkSafe BC in notifying British Columbia’s 300-odd sawmills they have two weeks to conduct a thorough inspection and implement an effective combustible dust control plan, following recent sawmill explosions in Prince George and Burns Lake, where four workers were killed and 41 injured. One sawmill, the Pope and Talbot sawmill in Fort St. James, British Columbia, has closed temporarily to clean up sawdust.

“The reason for sending out the directive order is directly linked to the second catastrophic explosion in Prince George,” said Roberta Ellis, senior vice president of corporate services with WorkSafe BC. “We’ve heard from workers, we’ve heard from unions, we’ve heard from employers. There’s a high level of nervousness and concern.” So why is this now a major problem, worse than in previous years? The answer is simple, according to the US Government’s Dept of FireScience Digest, and it’s all down to global warming!

Global warming increases the amount of beetle wood

Three years ago, in a report dated 3 February 2009, WorkSafeBC specifically warned of the danger posed by the dry wood killed by pine beetles, which produces a lot of dust, and noted an absence of monitoring the exposure to wood dust in processing saws and chipping heads in one specific plant.

Wood killed by pine beetles is exceptionally dry. John Allen, president and CEO of the Council of Forest Industries (COFI) advises that the industry is inevitably relying on older beetle wood, and it is not practical to reduce the consumption of such wood. “What we’re going to do is take steps to mitigate against any issues from sawmilling beetle wood, including dust,” he said following the meeting with the BC Labour Minister, WorkSafeBC, companies and unions. There has been much discussion about the challenges of processing wood killed by pine beetles because that wood is exceptionally dry.

Beetle epidemic over a wide area

The forests in British Columbia are the scene of what scientists consider to be the worst bark beetle epidemic ever. The US Government’s FireScience Digest says mountain pine beetles and spruce beetles have attacked lodgepole pine and Engelmann spruce over millions of hectares throughout the subalpine zones of the Rockies and have killed between 60 and 80 percent of the mature trees in some places.

The Digest says what is particularly concerning about this outbreak is that the beetles are pushing into new territories such as northern British Columbia, on the extreme edge of the mountain pine beetle’s historical range. The beetles have crossed the spine of the northern Rockies, apparently for the first time, and are now resident in Alberta jack pine forests. They have also spread upslope into alpine forests of whitebark and bristlecone pines, where cold temperatures have historically kept them out. They could well spread into other tree species that did not co-evolve with these beetle species and consequently have no defences against it.

The main factor in these new dynamics is a warming climate, the Digest says. Earlier snowmelt, a longer growing season, and milder winters favour an environment that drives beetles to reproduce more often in a season and allows more larvae to survive the winter.

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