PRINEVILLE, Ore. -- The second fire in five months at a Prineville hemp processing plant was caused once again by overfilling a holding tank with flammable liquid, a fire official said. The first led to a closure until a fire suppression sprinkler system was turned back on - but this time, the fire began outside the building,

Crook County Fire & Rescue was dispatched for an industrial fire at Central Oregon Processing, located on North Main Street, shortly before 9 a.m. on Monday.

Initial reports were there had been a flammable liquid spill at the Isolation Building and a subsequent fire, Division Chief and Fire Marshal Russell Deboodt said.

Fire crews arrived to find an exterior fire burning among outside mechanical equipment. The fire had also spread to the interior of the building. The fire suppression system in the building activated, Deboodt said, and was able to control further spread of the fire until crews arrived to completely extinguish the flames.

Crews were on scene for about three hours, as they worked to cautiously ventilate the building, ensuring the flammable gas vapors still present in the structure did not reignite.

The subsequent fire investigation determined the fire was caused by overfilling a holding tank inside the building. Due to the overfilling, flammable liquid flowed into vent piping which terminated above the roof of the structure. The flammable liquid then flowed off the roof, and came in contact with an exterior electrical outlet, igniting the gas vapors.

Crook County Fire & Rescue responded with two engines, and ambulance and three command vehicles, with a total of 12 firefighters. The district was assisted on scene by the Prineville Police Department and Pacific Power. Redmond Fire & Rescue provided a mutual aid ambulance for district coverage during the event.