MADISON, Wis. (AP) — Democratic Attorney General Josh Kaul has successfully withdrawn Wisconsin from a multistate lawsuit challenging a federal rule regulating certain air pollutants, including mercury.

The states are challenging a U.S. Environmental Protection Agency analysis that found regulation the pollutants would be reasonable because the costs of implementing new control technology wouldn’t raise retail electricity costs beyond historical ranges.

Kaul announced Monday that the U.S. Court of Appeals for the District of Columbia approved his motion to dismiss Wisconsin from the action on Thursday.

Earlier this month the 5th U.S. Circuit Court of Appeals approved Kaul’s request to withdraw Wisconsin from another multistate lawsuit challenging federal health care reforms.