MINNEAPOLIS — The U.S. Forest Service is downgrading an environmental review for a proposed copper-nickel mine in northeastern Minnesota.

The Forest Service says it will do an environmental assessment, rather than an environmental impact statement, on PolyMet Mining Corp.’s proposed project.

Supporters say the mine would bring hundreds of needed jobs. Opponents fear the mining could lead to sulfuric acid and other toxic chemicals into a watershed that leads to Lake Superior.

The Forest Service says it’s changing plans because no significant environmental impacts have been identified during a long public scoping period.

But the Campaign to Save the Boundary Waters said the change means less opportunity for public input and rigorous scientific analysis.