A fire early Thursday morning at Plum Creek Timber Co.’s medium-density fiberboard plant in Columbia Falls shut down a production line, but a second line was up and running by midafternoon.

All plant employees were safely evacuated and no injuries were reported, Plum Creek spokeswoman Kathy Budinick said.

Columbia Falls firefighter Karl Weeks said there were multiple spot fires as a result of an explosion inside the massive plant.

A total of 15 Columbia Falls and Whitefish firefighters responded to the call.

The fire was reported at 6 a.m. on the No. 1 production line where the wood fiber is held before it’s fed into the processing line.

“The fire suppression system worked as intended,” Budinick said. “There appears to be minimal damage to the operation.”

Plum Creek quickly restarted its No. 2 production line, and that line will operate while the No. 1 line will remain down as the company continues to investigate the incident and clean up and recharge the fire suppression equipment, she said.

The No. 2 line was built in 2001 for $80 million and manufactures a continuous-press thin fiberboard that’s one-tenth of an inch thick. The No. 1 line is older and produces thicker fiberboard of up to 1 1/4 inches thick.

No workers were laid off as a result of the fire. The plant employs 180 workers.

The medium-density fiberboard plant was last affected by a major fire in June 2014 when a catastrophic bearing failure on a raw material line led to explosions and fire that shut down the plant for a month.