A massive fire preceded by explosions hit the Plum Creek Timber Co. fiberboard plant in Columbia Falls on Tuesday afternoon.

Although an initial report indicated several dozen people could be unaccounted for, they all eventually were located and evacuated.

“All employees are present and accounted for with no injuries,” Plum Creek spokeswoman Kathy Budinick said.

“It was in the MDF [Medium Density Fiberboard] facility,” Budinick explained. “They worked hard to contain it.”

There were 66 workers and two contractors who were successfully evacuated from the burning plant.

Fire departments from across the Flathead Valley converged on the plant shortly after 3 p.m. after reports of an explosion and then a fire.

“I heard two or three loud explosions. It shook my house,” said Dorothy Downen, who is one of the closest neighbors to the fiberboard plant.

Richard L. Peterson also lives next to the plant. 

“I was working in the yard and heard an explosion, and figured it was from the fiberboard plant, because they’ve had one before,” he said. “It was like a bomb went off, a big old explosion.”

Peterson has three sons and two nephews who work at the plant, so immediately after the explosions he got on his ATV and rode along the railroad tracks next to the plant to make sure they were all right.

“They said everybody was accounted for,” he said.

Peterson said he was working there several years ago when there was another explosion.

“All that fine dust in there, all it takes is one little spark,” he said. “The whole thing goes up.”

Another observer said he heard one small explosion followed by a bigger blast. He thought it was a train derailment.

A Plum Creek office worker said one of two lines at the fiberboard plant blew up.

Flames initially were reported to be 40 feet high. As the afternoon wore on, thick plumes of smoke roiled out of the burning plant and one wall of the massive building appeared to be blown out.

“It’s too soon to see what caused it,” Budinick said of the fire.

At 4:30 p.m., firefighters still reported finding active fire inside the plant.

Firefighting reinforcements were still arriving at the scene well into the evening.

“As with any big explosion, pretty much everything in there was on fire,” Flathead County Sheriff Chuck Curry said.

Curry said his department initially responded after hearing there could be as many as 60 people unaccounted for.

“We responded primarily because we believed there could be a significant number of people injured or killed,” he said. “After that, our role was mainly support, perimeter control and traffic control.”

Curry said the only injuries he knew of were a couple of people with very minor smoke inhalation who were not transported to the hospital.

He said that after all the employees were accounted for, there was a delay in getting firefighters in to battle the blaze while they waited for Flathead Electric Cooperative and NorthWestern Energy crews to shut off electricity and gas.

Plum Creek spokeswoman Kate Tate said the entire Columbia Falls plant employs approximately 180 people.

Asked how many fire departments responded, Columbia Falls Police Det. Steve Hughes said: “Just about all of them.”

The all-hands-on-deck nature of the incident drew responders from the Columbia Falls, Evergreen, Whitefish, Bad Rock, Kalispell, Marion, West Valley and Glacier Park International Airport fire departments, Three Rivers EMS, the Flathead County Office of Emergency Services, the Montana Department of Natural Resources and Conservation and the U.S. Border Patrol.

The Plum Creek Multiple Density Fiberboard plant uses powerful grinding machines to reduce wood into fibers that are treated with resin-based glue and compressed at high pressure and temperature into panels. The fibers and sawdust can be very explosive when mixed with air.

Daily Inter Lake features editor Lynnette Hintze, Hungry Horse News reporter Chris Peterson and Bigfork Eagle editor Dave Reese contributed to this story.