The B.C. government is expected to order sawmills to remove accumulated sawdust, following the deadly explosion in Prince George, but several sawmills have already begun voluntary clean ups.

Minister of Jobs Pat Bell said at least one mill shut down completely on Wednesday for a voluntary cleanup.

"As I understand it, the Conifex mill in Mackenzie yesterday took some voluntary downtime to do some housekeeping," said Bell.

Bob Fleet, the vice president in charge of eight Tolko mills around B.C., said they're voluntarily doing what they expect safety inspectors at WorkSafeBC will soon order.

"We're on high alert and I would say that we will double-down on our housekeeping and pay special attention to any potential that might be associated with working with dead mountain pine beetle kill fiber."

The move comes as the investigation begins into what sparked Monday's deadly disaster that killed two and injured several others.

No cause has been officially identified by safety inspectors who are in the early stages of their investigation, but experts are looking at the possibility that a high concentration of wood dust in the air fuelled the massive explosion and resulting fire.

There is also speculation that wood dust also caused a similar explosion that killed two workers at a sawmill in Burns Lake, B.C. in January.

John Allan, the CEO of the Council of Forest Industries, said the cleanups are being done, but more research is need to determine if milling dry standing deadwood from trees that have been killed by pine beetles is actually to blame for the explosions.

"This wood is drier, it's harder to manage and reports are that the dust particles are finer, but this is research that we really need to do from a scientific perspective. In the meantime, we're taking these actions to prevent further tragedies," said Allan.