EPA asked to step in again, this time on DNR air permitting

Wisconsin conservation groups are again asking federal regulators to force the state Department of Natural Resources to get tougher on polluters.

A petition filed this week asks the U.S. Environmental Protection Agency to reject changes the state is poised to make to an air emissions permit for a frac sand mining company.

The permit would allow emissions of very small particles that are a serious health hazard when inhaled, said Sarah Geers, an attorney for Midwest Environmental Advocates, a public interest law firm in Madison...