A coal train enters the Craig Station power plant near Craig, Colo. on Tuesday, June 16, 2015.

(Nathaniel Minor/CPR News)

One coal-fired power plant in western Colorado will shut down and part of another will close in the next decade, under a deal aimed at reducing haze in nearby national parks and wilderness areas.

Environmental groups sued two years ago, alleging the plants in Craig and Nucla are damaging the air quality in nearby parks, in violation of federal clean air rules.

This week, Tri-State Generation -- the utility that uses power from both plants -- agreed to shut down the Nucla plant in the next seven years. And the New Horizon Mine, which supplies Nucla, will close as well.

One unit of three at the Craig power plant will close in the next 10 years. It’s unclear where the utility will get its replacement power. 

"The retirement of these two units combined could reflect about a 9.5 percent reduction in CO2 emissions from existing coal-fired units in the state," said Will Allison, director of Colorado’s Air Pollution Control Division.

The power stations in Nucla and Craig -- and the nearby mines that supply them – are major employers for both towns. Shutting down these plants could be a big hit for their local economies.

Utility officials say at least 90 jobs will be lost. Lee Boughey of Tri-State Generation said Thursday 93 people work at the Nucla Station power plant and the New Horizon Mine that supplies the plant. He says all those jobs will eventually be eliminated after the plant shuts down in 2022.

One unit of the Craig Station plant will shut down in 2025, but two others will keep operating. Boughey says Tri-State doesn't yet know how many jobs will be lost, but 280 people work there now.