Six Chippewa tribes hope the EPA agrees and either restricts or halts a mining company from extracting iron ore from the Penokee Hills.
The tribes insist an iron ore mine would pollute the water-rich region and tributaries flowing into lake Superior.
Tribal leaders have sent a letter to the EPA, asking it to examine the likely environmental impacts of a proposed open pit mine in Ashland and Iron counties, and if it would damage the watershed, to use the Clean Water Act to limit or stop project.
The company Gogebic Taconite has been testing the rock and has not yet submitted an application to the state, to mine the region for iron ore. After the firm would file an application, state regulators and the U.S. Army Corps of Engineers would review the proposal to determine whether it would adequately mitigate the environmental consequences.
The EPA recently agreed to intervene in proposed mines in Alaska because of the damage they could cause to water resources.