MINNEAPOLIS (AP) — The Environmental Protection Agency has agreed to consider whether pollution controls at Xcel Energy’s Sherco power plant are adequate for cutting haze over two national parks and the Boundary Waters Canoe Area.

The federal agency and six environmental groups filed a proposed consent decree Tuesday that obligates the EPA to take action on a 2009 National Park Service finding that haze from the coal-fired plant near Becker impairs the views at Voyageurs National Park in Minnesota and Isle Royale National Park in Michigan. The consent decree would settle a lawsuit the groups filed in 2012.

The settlement marks “an important milestone,” said Kevin Reuther, legal director for the Minnesota Center for Environmental Advocacy. But it’s only one of several reasons why Xcel should come up with a plan for “retiring this coal plant and replacing it with cleaner sources of energy,” he said Wednesday. Other reasons he cited include the EPA’s proposed new carbon emissions rules for power plants.

Minneapolis-based Xcel Energy has disputed that Sherco, the state’s largest power plant, contributes to the haze over the parks and the BWCA. It has asked the Eighth U.S. Circuit Court of Appeals to allow it to intervene in the lawsuit.

“Xcel Energy is reviewing the consent decree and assessing our options,” the company said in a statement. “We are waiting for the Eighth Circuit to decide whether we can be part of the litigation, and are disappointed the other parties are trying to move forward at this time. Xcel Energy has invested, and will continue to invest, in clean energy strategies that protect the environment, improve the electricity system and provide value to our customers.”

Xcel told state regulators last July it was cheaper to continue burning coal at the plant near Becker rather than converting it to natural gas, at least until the future landscape for environmental regulations became clearer.

Under the consent decree, the EPA has to propose a plan by Feb. 27 and finalize it by August 2015.

The EPA first must decide whether the National Park Service was right when it certified that the haze problem at the parks was “reasonably attributable” to the plant’s emissions, Reuther said. If so, then the EPA would determine what kind of pollution control technology is required, he said. Adding it could require an expensive investment by Xcel, which would have just five years to install it.

“This is a major step toward clean air in Boundary Waters, Voyageurs and Isle Royale,” Stephanie Kodish, director of the Clean Air Program at the National Parks Conservation Association, said in a statement.

The EPA must publish the proposed consent decree in the Federal Register and hold at least a 30-day public comment period before the settlement goes to a federal judge for approval.

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