Bearing failure blamed on Plum Creek explosion

A bearing failure on a raw material feed line caused a fire and explosions at the Plum Creek medium-density fiberboard plant in Columbia Falls on June 10, according to company spokesperson Kate Tate.

“The failure ignited both wood fiber and the belt, and heat from that fire caused insulation on the duct pipe above it carrying wood fiber to catch fire, and then the fire on the outside of the pipe had enough heat to cause the fiber on the inside to catch fire,” she said.

Air mixed with fine wood fibers provided the fuel for a series of explosions in the duct work.

“Knowing this, we can design fire protection for this area of the plant to prevent future bearing failure issues,” Tate said.

The large explosions were heard across Columbia Falls and blew metal sheeting off exterior walls. The resulting fire filled the buildings with fire and thick smoke. The black smoke seen by onlookers largely came from the burning conveyor belt. No plant workers were injured, although some were treated for smoke inhalation.

Tom Ray, Plum Creek’s vice president of northwest resources and manufacturing, said in a June 11 press release that the MDF plant should be up and running in a month.

“Operations are expected to resume in approximately 30 days,” Ray said. “We will provide an update to our plans should that be necessary.”

Ray praised the firefighters who battled the blaze.

“Everyone at Plum Creek commends the efforts by fire departments to protect the people working at the facility,” he said. “Their work is greatly appreciated.”

The fire drew a countywide firefighting effort, with nearly 70 emergency services personnel on the scene at one point. The initial call came out at 3:10 p.m., and firefighters found Plum Creek employees battling the fire when they arrived.

“They have a complete hydrant system, and all the sprinklers and deluge systems in those areas were activated, and they were manning their own in-plant hose line,” Columbia Falls fire chief Rick Hagen said.

Plum Creek maintains a 3 million gallon water tank at the site, and the cool and rainy weather helped, Hagen said.

Plant employees had begun to shut off power in the plant but were immediately pulled back and replaced by firefighters with breathing gear. Once MDF workers were all accounted for and the gas and power were shut off, firefighters were divided into three divisions under one incident command and headed into the multi-story plant.

“They pretty much operated independently of one another, covering their own particular portion of the building,” Hagen said. “As they ran out of air, they would rotate fresh crews in, and they just kept rotating people.”

Hagen said there were fires all over the place, “from pretty good-sized fires to spot fires.” Plant workers helped guide firefighters where they could, he said.

“Flathead County’s mutual aid system worked well,” Hagen said. “Every bit of resources we requested were delivered in a timely fashion.”

Firefighters left the MDF plant sometime before 10 p.m., and Plum Creek workers stayed overnight to monitor the site. Firefighters returned around 4 a.m. after a fire was found in a raw materials storage building connected to the main MDF plant by conveyors and duct work.

The last firefighters left the site about 12 hours later after putting out the fire in the storage building and then standing by while plant workers washed down the buildings, trying to get all combustible materials on the floor.

Hagen called the incident a “perfect storm,” with the fire resulting from the explosion outrunning the fire suppression system. Even so, the sprinklers played a significant role in partially knocking down the fire, which could have been much worse, he said.

“The fact that no one was hurt was very good news — and remarkable,” Hagen said.

The MDF plant uses powerful grinding machines to reduce wood into fibers that are treated with resin-based glue and squeezed at high pressure and temperature into panels. The wood fibers and dust created by the process can be very explosive when mixed with air, and the plant has an extensive dust collection system.

All told, 19 Columbia Falls volunteer firefighters fought the fire, joined by firefighters and emergency personnel from the Kalispell, Evergreen, Whitefish, Bad Rock, West Valley, Bigfork, Blankenship, Glacier Park International Airport and Marion fire departments, Flathead County Office of Emergency Services, Flathead County Sheriff’s Office, Columbia Falls Police Department and Three Rivers EMS.