The fire broke out at 9 p.m. in the 165th block of Case Road, in an area where construction crews have been widening Interstate 5, according to West Thurston Regional Fire Authority Lt. Lanette Dyer. The fire was in a gravel area where crews were bringing debris from the widening to be chipped, she said.
Investigators think spontaneous combustion started the fire, Dyer said.
“What happens when you have a lot of the wood and you have chipping, the layers of those dead fuels begin to compost down and they create heat once they are composting,” Dyer said.
That heat, combined with weather conditions that prompted a statewide burn ban, have investigators believing the fire was caused by spontaneous combustion, Dyer said.
The area is filled with stumps, brush, sawdust and chips, said Department of Natural Resources spokesman Kent Stanford.
DNR investigators took over Wednesday morning and are working to verify the cause.
The fire is contained, but “it’s going to be a long operation,” Stanford said. “We have heavy equipment on site to remove stumps and large-diameter debris so we can dig into the sawdust and refined materials and extinguish those.”
Firefighters will move and extinguish debris during the day and monitor the area at night. Sprinkler systems will cool the area at night.
As many as 50 fire personnel initially were involved, Dyer said. There are now 25 to 35 crew members at the scene, Stanford said. Crews from the West Thurston, Griffin, Oakville, Tenino and Bald Hills fire departments, Riverside Fire Authority and Department of Natural Resources pitched in.
The fire initially threatened about 10 homes, four of which were in “pretty high danger,” but none was evacuated, Dyer said.
About 10 2,500-gallon water tenders from around the county came to shuttle water to the remote area.
Crews have been out to the area for several small fires and calls about burn-ban violations, Dyer said.
Gov. Chris Gregoire issued a statewide ban Sunday, prohibiting all outdoor burning.
Not everyone is obeying, Dyer said.
“Continuously, we are going out daily on burn-ban complaints from neighbors and people concerned about their property,” she said. “Not only is it illegal, but just plain dangerous.”