Coal ash spilled into Lake Michigan after a bluff collapsed below a coal power plant. But experts tested the waters and say the coal ash is so diluted that it should pose no threat to human health. The Sierra Club is suing the power plant owner. The group claims the company is violating the state's environmental laws and alleges the coal ash does pose a serious threat to health and the environment.

Minnesota's Department of Commerce recommends closing Minnesota Power’s five oldest coal-fired power plants by 2020 to save consumers money. The Duluth News Tribune reports environmental groups have also sent letters urging the Public Utilities Commission to close the plants to reduce emissions.

A transformer lockout at the Monticello nuclear power plant prompted an automatic shutdown Friday afternoon. Xcel Energy says the malfunction interrupted non-safety-related power, but that all safety systems functioned as designed.

Clean-energy supporters are demanding that the Minnesota Public Utilities Commission order Xcel Energy to better plan how it will retire the two oldest and dirtiest coal-fired power plants at its Sherco Generating Station, which produces electricity for the Upper Midwest, the Pioneer Press reports. Renewable advocates packed an all-day hearing Thursday at the commission. They say Xcel has failed to study how wind- and solar-generated energy might replace the Sherco units.

Coal plants in our neighbor state have been violating clean air rules for years with little push back from state or federal regulators, according to a report from the Wisconsin Center for Investigative Journalism and other news organizations. But the nonprofit Sierra Club has campaigned for a decade and applied legal pressure to force energy producers to cut emissions.

An estimated six to eight people were hurt in a 12-foot deck collapse at a home in Forest Lake Saturday night, authorities with the Washington County Sheriff's Office say. The deck was reportedly loaded with more than two-dozen people who gathered for a photo when it collapsed. The extent of their injuries remains unclear.

The state of North Dakota and its coal power industry want to overturn a Minnesota law that limits imports of electricity generated by coal. Critics claim the law is unconstitutional and unfairly limits business between the states.