No employees were injured and an investigation into the cause of the 3:30 a.m. blast is ongoing, said Hank Ricklefs, Plum Creek's vice president for manufactured products in Columbia Falls.
He said damage from the explosion and fire did not appear to be extensive. Most of the damage was to the building structure and not to key machinery or production controls, he said.
The explosion apparently occurred on one of the two production lines in the building used to make fiberboard. The second line was shut down temporarily as a precaution, Ricklefs said.
``The crew on duty immediately implemented established emergency procedures and our fire response plan. These actions contained the fire and ensured the safety of employees,'' Ricklefs said.
The Columbia Falls Fire Department responded and Ricklefs said the fire was extinguished within two hours.
