Probers zero in on ‘beetle kill’ dust
Worksafe says blast cause possibly a combination of fuels
Samples have been sent to a lab in the U.S. for analysis to determine if the concentration of dust prior to the blast which destroyed the Burns Lake sawmill could have served as a fuel source.
During an investigation update Wednesday, Robert Ellis, vicepresident of investigations for Worksafe B.C., said investigators are also looking at other possible fuel sources, including natural gas and propane, and several possible ignition sources such as hot surfaces, electric arcs from switches and motors.
“We are not looking at one single element in isolation,” Ellis said. “We are looking at how they [could have] potentially caused this catastrophic event.”
The type of wood being milled prior to the incident is also being examined, amid growing speculation that the processing of beetlekill wood, known to produce a fine powder, has been responsible for a string of recent mill blasts.
The explosion, in January of this year, killed two mill workers and injured 19.
Last month, Worksafe B.C. ordered the inspection of all mills in B.C. after a massive explosion on April 23 at the Lakeland Mills plant in Prince George killed two and sent an estimated two dozen to hospital.
Worksafe is also investigating that explosion and is following up on two non-fatal blasts last year at mills in Williams Lake and Armstrong that went unreported to the agency, said Donna Freeman, spokeswoman for Worksafe.
Following the Burns Lake incident, Worksafe ordered the inspection of 70 mills throughout the province to ensure safety standards were being met. Of those inspected, 90 violation orders were issued, the details of which were not made available on Wednesday.
Freeman said the Prince George site was one of those inspected — on March 15. An earlier inspection report, dated Feb. 6, noted that the accumulation of wood dust, and the requirement to prevent buildup, were discussed.
It was noted that the airborne concentration of wood dust appeared to be “below the exposure limit.”
Meantime, Ellis said the investigation into the Burns Lake explosion will take another two to three months. Arson and lightning strikes have been ruled out as an ignition source, he said, adding that nothing indicates hot oil, hydraulic oil, gear oil, or oxygen and acetylene served as fuel sources.
Exhaust and ventilation systems are also being looked at, as is the effect extreme cold weather may have had on the mill’s water pipes and misters, said Ellis.