Police are treating a blaze which ripped through an asbestos-riddled timber mill in the South West on Friday morning as suspicious. People are being warned to keep their windows closed and stay inside as the fire billows hazardous smoke just kilometres from the timber town of Pemberton. Pemberton and Manjimup Volunteer Fire and Rescue Service and Bush Fire Service firefighters were called to the old Pemberton Timber Mill at 5.09am, with crews working to control and contain the blaze. While no longer operational after shutting down in 2016, the building still contains equipment owned by WA’s biggest hardwood timber operator, Parkside Timber, believed to be worth millions of dollars. Photographs show flames burning the building from the ground up to the ceiling, with parts of the structure appearing to have been completely gutted by the flames. Pemberton police Sgt Gavin Barke said police were investigating the circumstances surrounding the cause of the fire, which they were treating as suspicious. He said the building was “structurally unsound” and contained hazardous material, including oil drums and tyres. The Department of Fire and Emergency Services issued an updated warning for the fire just after 1pm, advising the blaze was contained but not controlled. Locals have been told to remain inside, out of the smoke or fumes, with doors and windows closed. They have also been asked to disconnect their rain water tanks until their gutters and roofs have been flushed by rain as water may not be safe for drinking. Residents in Pemberton have been asked to restrict their water use to essential purposes until Sunday to help maintain water supply for firefighting. DFES is also advising people to switch off their air-conditioners and stay away from the area. If you have any information about the fire, call Crime Stoppers on 1800 333 000. People with medical concerns should contact their local doctor or phone Health Direct on 1800 022 222.