Plum Creek officials say their investigation of Tuesday's explosion and fire in their Columbia Falls MDF plant was caused by a "catastophic bearing failure."
Friday evening Kate Tate, the communications director for the company, told NBC Montana the failed bearing was part of the raw material feed line in the plant.
The overheated bearing started a fire on the conveyor belt. The flames spread to an overhead duct pipe carrying wood fiber. A series of explosions happened when the wood fiber in the duct exploded.
No injuries were caused by the fire or explosions.
Thursday we were told Plum Creek's MDF employees would stay on the jog, cleaning up and making repairs to put the plant back in operation.