MADISON, Wis. — A number of groups are challenging a settlement the state Department of Natural Resources reached over large livestock farm regulations.

Midwest Environmental Advocates filed a lawsuit Friday on behalf of the Clean Water Action Council, Milwaukee Riverkeeper and the Wisconsin Wildlife Federation alleging the settlement opens the door to pollution and the public never got a chance to provide input.

The Dairy Business Association sued in July alleging the DNR improperly blocked farms from using vegetation patches to filter pollution, improperly assumed oversight of calf hutches and illegally requires farms to get pollution permits regardless of actual pollution.

The DNR settled the case in October, agreeing vegetation patches are valid pollution-control systems and to stop regulating hutches. The dairy association agreed to drop its illegal permit claims.