WorkSafeBC's lead investigator told a coroner's inquest Wednesday there is "absolutely no evidence" to support a possibility that static electricity from an air wand was the ignition source for the blast that leveled Lakeland Mills two years ago, a coroner's inquest heard Wednesday.
Paul Orr conceded WorkSafeBC could not rule out the chance that an air wand, which one of the two men who died from injuries suffered in the April 23, 2012 explosion had been using to clean off machinery, was producing static electricity but maintained the ignition source laid elsewhere.
Glenn Roche, 46, and Alan Little, 43, died from the severe burns they suffered in the disaster, which also left more than 20 others with injuries, many of them serious.
Earlier this week, Paul Way of CASE Forensics, which conducted a separate investigation on behalf of Lakeland's owner, devoted a significant portion of his testimony to the theory that static electricity from Roche's air wand created the spark that led to the explosion.
However, he also stressed there was not enough evidence to reach a firm conclusion on the possibility, finding only that it was the "most likely" of the scenarios considered.
On Wednesday, Orr said the fact Roche was blowing down machinery in the vicinity of where the explosion originated was among the first pieces of evidence WorkSafeBC investigators considered.
Orr said investigators subsequently consulted with WorkSafeBC's in-house electrical engineers and were told it's not the air in the hose that creates static electricity but rather the particles in the air.
But because they were unable to get a sample of the air from the hose work, which was completely destroyed, "we had no way of testing to see what level of static electricity would be developed at that time," Orr said.
But he said blast patterns and other evidence led WorkSafeBC to conclude the explosion's origin was a faulty gear reducer in the sawmill's basement, below where Roche had been working on the operating level.
One piece of evidence Way's team relied on to dispute that finding was the discovery of a plastic bucket a few feet away from the gear reducer that had remained in place despite the explosion. Orr said the bucket was pushed down and "fitted snugly" into some framework to catch oil from another gear reducer and motor above. It remained in place because the initial deflagration went in a different direction and had spread above where the bucket was located, Orr said.
Orr said a key piece of evidence supporting WorkSafeBC's conclusion was the discovery that the booth Roche occupied when the machinery was operating was dislodged in such a way that the explosion had to have come from the basement.
