Broken pipe releases oil into the Clark Fork

NOXON, Mont. — Avista is working with emergency and environmental agencies to assess and manage an oil spill on the Clark Fork River.

The utility said the spill was discovered at the Noxon Rapids dam on Thursday at about 12:30 p.m. Avista said it immediately implemented emergency spill procedures and is working with local, state and federal agencies to conduct clean-up operations.

Avista estimated approximately 1,250 gallons of oil were spilled, the majority of which wound up in the river.

The extent of the spill was not disclosed on Friday.

Avista said dam operators discovered that a quarter-inch pipe carrying transformer oil had broken and was spilling onto the transformer deck. The deck contains stormwater drains and oil from one of those drains was released into the river between the Noxon Rapids and Cabinet Gorge hydroelectric projects, both of which are owned and operate by Avista.

A preliminary assessment found that ice had collected on the face of the dam and broken off, busting a pressure gauge on the valve of the pipe. Operators immediately shut off the valve manually once the leak was discovered.

Avista did not disclose how long it’s believed the pipe was leaking. Oil was discovered downstream of Noxon Rapids and boats with trained personnel were deployed to begin clean-up efforts.

Avista said it does not believe the spill poses a long-term threat to the river, fish or wildlife.