Clean air advocates filed a lawsuit Wednesday over pollution from Xcel Energy's Sherco plant in Becker, Minnesota's largest power plant.
Six groups claim the coal-fired plant is unhealthy for nearby residents and a major contributor to haze that obscures views of Voyageurs and Isle Royale national parks and the Boundary Waters, the Associated Press reports.
According to the Star Tribune, the groups allege the EPA hasn't enforced longstanding rules under the U.S. Clean Air Act to reduce the haze. If the suit is successful, the court order would require Xcel to install a $340 million piece of technology to cut emissions.
An Xcel spokesperson tells the newspaper that the Sherco plant is not the cause of the visibility problems in Voyageurs and the BWCA.
The company is currently investing $50 million in improvements at the Becker plant to comply with separate regional haze regulations under the Clean Air Act.