ST. PAUL, Minn. (AP) — A federal appeals court has rejected a challenge by environmental groups to Minnesota’s plan for reducing haze over Voyageurs National Park and the Boundary Waters Canoe Area.

The 8th U.S. Circuit Court of Appeals on Thursday let the Environmental Protection Agency’s approval of Minnesota’s rules stand.

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At issue was whether the state’s plan should have mandated the use of “best available retrofit technology,” or BART, for power plants contributing to regional haze. The state instead adopted a cap-and-trade approach to emissions called the “transport rule,” and a set of goals for improving visibility.

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The EPA concluded the transport rule was “better than BART,” but the environmental groups disagreed and asked the appeals court to review the decision.

A three-judge appeals panel says the EPA acted rationally in approving Minnesota’s plan.

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