Environmental watchdogs are warning Montana officials against letting Talen Energy cut corners in its cleanup of toxic coal ash pods in Colstrip.

Earth Justice wrote Montana’s Department of Environmental Quality last week about concerns with Talen Energy’s recently submitted cleanup plans.

Talen, co-owner and operator of Colstrip Power Plant in southeast Montana, recently cut time and money from its estimated cleanup of ponds containing coal ash. Capping the ponds is expected to cost more than $113 million. The work is expected and take until 2049.

But Talen’s cleanup plan appears to leave several tasks undone, said Jenny Harbine, EarthJustice attorney based in Bozeman. The cleanup planning has been underway for years.

“It’s time for DEQ to step up and require effective cleanup as soon as possible,” Harbine said.

EarthJustice, the Montana Environmental Information Center and the Sierra Club argue that the latest Talen proposal will not completely detoxify Colstrip groundwater. Instead, the proposal suggests that water right holders be prohibited from using the water.

The environmental groups also suggest that DEQ look to other coal ash cleanup projects around the country where ash is being removed to prevent future contamination.

Colstrip ash is staying put, according to Talen plans. The company plan allows the pond water to drain into the ground before capping over the contaminated area and adding more ash, Harbine said. So long as the ash is present, there’s a chance for future contamination.

Big changes are underway for how ash produced from coal burning is handled at Colstrip.

Talen begins de-watering ash ponds this year, after which the ash will be dry stored. That’s a big change from the way ash has been stored in ponds for the past 30 years. It’s that pond storage that has contaminated area groundwater. Roughly 200 million gallons of contaminated water seep from the ash ponds, rendering the groundwater undrinkable.

The town of Colstrip gets its drinking water from the Yellowstone River 30 miles away, from a pipeline that also provides water to the power plant.

Coal ash sludge contains lead, arsenic, boron and other toxic chemicals that can cause liver, kidney, brain and testicle damage. The cost of capping the ponds is just a fraction of what’s expected to be spent as cleanup begins and the four-unit power plant edges toward shutdown.

Colstrip Units 1 and 2 will shut down no later than 2022 under a 2016 legal settlement to resolve air pollution concerns. Three of the five of owners of Units 3 and 4 plan to cut ties with Colstrip within nine to 17 years.

Talen is expected to de-water its bottom ash by the end of December and begin dry storage of the ash in 2019. Bottom ash is ash captured from the incinerator after coal is burned. The ash is a prime source for the boron.

There is also fine ash caught by air pollution scrubbers in Colstrip’s smokestacks. Talen is running tests now for cleaning up the fine ash.

The plan is to recycle the ash pond water as much as possible for use in the power plant. The ponds cover roughly 800 acres.

Talen’s power plant co-owners are Washington state utilities Puget Sound Energy and Avista Corp.; Oregon utilities PacifiCorp and Portland General Electric; and NorthWestern Energy, which serves half of Montana’s population.

In 2008, the power plant owners were sued by 57 Colstrip residents over the decades of groundwater contamination from the power plants’ numerous ash ponds.

The Colstrip plaintiffs settled with the power plant owners, but the pollution persisted as the ash ponds continued to leak. In 2012, the Montana Environmental Information Center, The Sierra Club and the National Wildlife Federation sued DEQ and the power plants’ owners, accusing them of doing little to stop the ash pond contamination.

The 2012 lawsuit resulted in a 2016 settlement, in which the power plants' owners agreed to stop pooling toxic coal ash and sludge beginning in 2019.