WorkSafe B.C. is studying several factors that may have caused the Jan. 20 explosion and fire at the Babine Forest Products sawmill.
In its latest report, the agency says it is investigating sawdust and production levels as well as wood type, ventilation and cold weather effects as potential causes.
So far, the report says there is no evidence that oil, oxygen or acetylene fuels contributed to the explosion, but the agency refuses to rule them out and other fuel sources, such as natural gas and propane, are still being investigated.
Evidence from a 50 square-foot area has sent to three separate labs and identified as a key part of the investigation said WorkSafe Senior Vice President Roberta Ellis.
But Ellis cautioned against any quick conclusions.
“I want to reiterate that this investigation is still ongoing and will take another two to three months to complete,” she said.
Ellis said so far there is no evidence to suggest the explosion was caused by arson or lightning.
“This may seem unlikely but we did receive evidence from witnesses about the occurrence of lightning,” she said.
Ellis said that while there has been media interest in sawdust as a cause of the blast, WorkSafe B.C. is investigating all possible fuel sources.
“It is impossible to rule out tiger torches in use the day of the incident, metal halide lights that burn at 900 C, open flame from welding torches or static electric discharges. Initial access to the scene was prevented by fire, the unsafe structure and a minefield of acetylene bottles and other hazards buried beneath the snow.”
When firefighters flooded the burning mill site with water, Ellis said it froze over in the -41 C temperatures that week.
“Investigators were chipping away at the ice for quite some time to get at the equipment,” she said.
Ellis said the investigation is moving as fast as it can.
Since the BFP explosion, Ellis said WorkSafe B.C. inspectors have sent out orders to 341 sawmills, resulting in 70 inspections that found 90 violations.
Ellis said she could not confirm if the Lakeland Mill was one of the mills visited by inspectors.
Twenty investigators are actively involved in the BFP investigation, Ellis said, adding that WorkSafe will in no way slow down that investigation as it begins looking into Lakeland.