WorkSafeBC has launched an investigation into the cause of an explosion and fire at a forest products mill in Quesnel, B.C.

Al Johnson, vice-president of prevention services, said a team of WorkSafe investigators took over the scene from the RCMP on Thursday morning, barely 12 hours after fire tore through a section of the WestPine medium-density fibreboard mill, about 600 kilometres north of Vancouver.

Between eight and 30 workers were on site when it happened at about 5:30 p.m. Wednesday and all were safely evacuated, he said.

“This is a concerning incident to us. We’re very fortunate that there were no injuries,” Johnson said. “Our support goes out to the community as well, because this is people’s livelihoods.”

WestPine is owned by Quesnel-based West Fraser Mills Ltd. (TSX:WTF).

Johnson said while it’s too early to speculate on the cause of the fire or explosion, they occurred in an area with four baghouses, or dust collection towers, that were either directly or indirectly involved.

“There is wood dust and wood fibre in that area, so that may have been a contributing factor, but we don’t know anything in detail at this point.”

Johnson said the mill had been part of a combustible dust inspection strategy that was developed following separate fatal explosions at sawmills in Burns Lake and Prince George in 2012. Four men were killed and 42 others injured in those incidents.

He said medium-density fibre board or MDF facilities are slightly different from sawmills or pellet mills, but they have been part of the “journey and evolution” in the industry to deal with wood dust.

WorkSafeBC has done about 10 inspections of WestPine since 2012 and it demonstrated it had a compliant program for management of combustible wood dust, he said.

“Our focus was on some other facilities throughout the industry that weren’t nearly as evolved as this particular facility was with respect to managing dust,” Johnson said.

Quesnel’s mayor said the explosion and fire badly damaged the side of the mill where raw material, such as sawdust, is fed into the plant

“West Fraser is a good company, they have a very strong safety track record, so I knew they would have their safety systems in place,” said Mayor Bob Simpson.

After speaking to the fire chief, he said it will take time to determine what caused the fire and where it started.

“There was certainly an explosion outside of the building and the fire they had to fight initially was outside the building, but he indicated that doesn’t mean that’s where it started,” he said. “They won’t know where the original start was until they do a full investigation.”

About 100 people are employed at WestPine MDF and manufactures plywood-like boards known as medium density fibreboard, used for furniture and other construction.

“West Pine MDF has been a stable part of our forestry complement here in town. Every job they create for us is an important job,” said Simpson.

West Fraser spokeswoman Tara Knight said the company did not have an estimate of when the mill will resume operations.