The Columbia Falls Aluminum Company will start doing further testing and more environmental investigation at the Superfund site north of Columbia Falls starting this fall and running into December, the company said recently.

The idea is to get some of the preliminary work for the cleanup done this year as the company negotiates a consent decree with the Environmental Protection Agency and the state Department of Environmental Quality.

Once the decree is finalized, it goes through the U.S. Department of Justice and is then approved by a U.S. District Court judge.

The decree lays out the legal parameters for the cleanup as well as future monitoring and other specifics for the long defunct aluminum plant site.

The preliminary work, known as an Unilateral Administrative Order, will cost about $3.5 million, paid for by the company, noted Columbia Falls Aluminum Company project manager John Stroiazzo. The company also pays for EPA and DEQ staff time.

The additional work will include soil sampling, drilling of new monitoring wells as well as other borings and water sampling. They will also investigate a domestic landfill used by the plant that is north of the west landfill. 

Further testing will be done on the caps of landfills that are known to contain asbestos. A drainage sluice that takes water from the Cedar Creek Reservoir at high water will be lined to keep it from leaking into the landfills.

“We are seriously starting the remedial process,” Dick Sloan of the DEQ said.

Stroiazzo said the new monitoring wells are a “reconfirmation of where the (cyanide and fluoride) plume is.”

It’s been a long time coming. The old aluminum plant ceased production entirely in 2009 and was placed on the Superfund list in 2016.

Since then the plant has been torn down and scrapped while hundreds of water and ground samples have been taken, identifying a plume of cyanide and fluoride groundwater contamination that’s leaking from the west landfill and the former wet scrubber sludge pond.

The plan is to put a slurry wall about three feet thick around the pond and the landfill to stop the contaminants from spreading into the groundwater. The hope is that over time, there will be enough dilution outside the wall to flush the contamination out of the groundwater, though the landfills and pond will remain contaminated in perpetuity, but contained by the wall.

If the wall doesn’t work, the plan is to put a treatment facility onsite that will take the cyanide and fluoride out of the water, clean it to safe standards and then re-inject it back into the ground.

All told, the project is expected to cost about $57 million. The wall, if the consent decree is finalized, should go in in 2027.

Columbia Falls Aluminum Company no longer owns most of the land. It sold about 2,200 acres to developer Mick Ruis. It retains ownership of about 200 acres, which includes all of the landfills and contaminated soils and other dumps and ponds associated with the plant.

Ruis has immediate plans for housing units on about 150 acres of land to the east, which is outside of the contaminated area. He also has set aside about 1,200 acres for future recreational use.

The new housing would be served by city sewer and water. It would not use groundwater in the area, even though wells in that location haven’t shown any contamination.  

The landfills have been leaking since at least the early 1990s when the DEQ first brought up concerns about them, according to stories in the Hungry Horse News at the time.

Stroiazzo spoke to concerns about per- and polyfluoroalkyl substances, which have come up recently at other meetings.

“There is no indication the smelting process produces those constituents,” he said.

The testing work this fall should have minimal, if any impact to the community or surrounding neighborhood. Crews will be working six days a week.

Some of the wells, which will actually be on land owned by Ruis, are intended for long-term monitoring.

There will also be testing of materials for the slurry wall, Stroiazzo said.

About 25 people attended a recent meeting and one concern was the Flathead River. 

While concentrations of cyanide are high near the dumps, about 4,000 parts per billion, by the time the plume reaches the high river bank, they’re about 400 parts per billion. 

The safe water drinking standard is 200 parts per billion, though no cyanide has been detected in the surface water of the river or in nearby residential wells.

People also wanted to know about the possibility of independent monitoring while the tests are being done.

They could do that through the EPA’s Technical Assistance Grant program, noted EPA project manager Allie Archer.  The Coalition for a Clean CFAC, at one point, had applied for that program.

Archer noted that under Superfund law, the site will have continued monitoring at least every five years.

“The EPA and DEQ will be around forever,” she said.

Stroiazzo also painted a different picture of the pollution overall. 

“CFAC didn’t generate this issue, we came after it,” he said.

The landfills and the contamination were buried long before Glencore, CFAC’s parent company, bought the plant. That includes tons of spent potliner – the source of the cyanide. When CFAC operated the plant, it had the potliner hauled away to a landfill off site.

ARCO, the previous owner, has been held partially responsible by the courts for about 35% of the cost of cleanup.