POST FALLS - A two-alarm fire in the sawdust delivery system at Plummer Forest Products caused equipment damage on Wednesday night, but didn't spread to the structure.

Kootenai County Fire and Rescue responded to the Post Falls operation at 401 N. Potlatch Road at 7:46 p.m.

"The cause was more than likely hot material that came out of the dryer," said Dan Ryan, KCFR division chief, adding that the business was in operation when the fire was reported. "It's the nature of the beast. That sawdust, especially in suspended dust form, is pretty easy to ignite."

Upon arrival, crews found smoke coming from a storage silo and a bag house with eventual fire spread to a main sawdust storage building.

With assistance from Plummer Forest Products personnel, crews opened access hatches to three hoppers, the kiln dryer, an enclosed auger and a dust collection bag house to contain and extinguish the fire.

A piercing nozzle was used to poke through the interior wall siding of the storage building and extinguish burning sawdust within the walls.

Ryan said the fire department has responded to the site, formerly owned by Potlatch, multiple times over the years.

"Every call I've been to out there has been related to the movement of sawdust through machinery," he said.

Ryan said generally the fires have been isolated to one piece of equipment, but this time the material was moving when the fire started so the blaze spread to other parts of the system.

"This one was more involved," he said.

Ryan said an estimated cost of damage hadn't been determined when fire crews left at 1 a.m. on Thursday. Firefighters remained at the business after the fire was extinguished to check for hot spots using a thermal imaging camera.

"Fires in sawdust are time consuming to extinguish and clean up due to ease of ignition and spread," Ryan said.

Coeur d'Alene Fire and Northern Lakes also responded.

KCFR was called to the business again on Thursday night as a fire rekindled in the sawdust, but it didn't spread.

"It started to smolder in one of the silos we had problems with (Wednesday night)," Ryan said. "It's an area that finally got air, so it started to smoke a bit."