MINNEAPOLIS — An environmental group petitioned federal regulators Thursday to strip the Minnesota Pollution Control Agency of its delegated authority to regulate water pollution from mining.

WaterLegacy filed a petition with the Environmental Protection Agency that alleges the MPCA is failing to meet its responsibilities that the EPA has granted it to enforce the Clean Water Act and other federal regulations in Minnesota.

The 33-page petition, backed by 445 pages of exhibits, said the MPCA has allowed a backlog of mining permit renewals to build up, and routinely grants variances from water quality standards without adequate review, allowing iron mining companies to continue to discharge pollutants instead of imposing effective controls.

The petition also said a law recently passed by the Legislature that delays enforcement of rules to protect wild rice from sulfate pollution from mining and other sources provides the EPA with additional legal grounds for withdrawing Minnesota’s authority. And it says mining companies exert undue influence on the state, undermining its ability to ensure compliance with the Clean Water Act.

WaterLegacy attorney Paula Maccabee said the EPA needs to step in and withdraw the state’s authority if it doesn’t take corrective action.