MADISON, Wis. (AP) — Wisconsin environmental officials are over-regulating large livestock operations, imposing pollution requirements that are tougher than federal law and arbitrarily changing runoff standards without going through the rule-making process, a trade association says in a lawsuit.

The Dairy Business Association filed the lawsuit in Brown County on July 31. It alleges the Wisconsin Department of Natural Resources has changed requirements for concentrated animal feeding operations to treat runoff. The department last year stopped allowing farmers to move runoff through patches of vegetation to filter pollution without going through the administrative rule-making process, the lawsuit said.

The department also has assumed oversight of calf hutches without going through the rule-making process, the lawsuit added.

What’s more, the agency is illegally requiring all the feeding operations to obtain a pollution discharge permit regardless of whether they actually discharge any pollution into state waters. That requirement violates state statutes that say the department’s pollution rules can’t be tougher than federal law, which requires a permit only for actual pollution discharge.

The lawsuit seeks judicial orders prohibiting the department from enforcing the new runoff guidance as well as declaring the regulation of calf hutches invalid and the rule requiring blanket discharge permits unenforceable. No court activity has been scheduled yet, according to online records.

“The self-aggrandizement by state agencies expanding their regulatory authority threatens the very nature of our republican form of government by undermining the representative democratic foundations upon which it is laid,” the lawsuit said.

A department spokesman declined comment, saying the agency doesn’t talk about pending litigation.

The lawsuit comes as conservationists are calling for tougher pollution standards for concentrated feeding operations.