A company that converts cow manure into gas energy has sued Weld County commissioners in federal court claiming their “irrational” decision to shut down the renewable energy company’s $115 million plant was based on a relatively small number of complaints even though it is in compliance with county odor levels.

The lawsuit was filed Tuesday in Denver U.S. District Court on behalf of Heartland Biogas of San Diego against five Weld County commissioners. It claims the officials abused the company’s constitutional due process rights when they suspended its special review permit on Dec. 19.

Heartland is seeking monetary damages against the county and reinstatement of its special review permit. The lawsuit claims the government decision could cost the company $29.4 million in shutdown costs, $3.2 million a month in profits, and permanently damage its contracts with local ranchers and gas companies.

Messages left with county officials on Wednesday were not immediately returned.

On its website, officials tout Weld County as the third-largest county in Colorado with thousands of acres of prime agricultural land. Heartland uses an anaerobic digester system to convert cow manure and food waste from local ranches into natural gas. After the gas is cleaned and compressed, it is injected into the Colorado Interstate Gas Company pipeline.

The facility, which employs 39 full-time-equivalent employees, is one of the largest anaerobic facilities in the United States. Its output is comparable to a 20-megawatt electrical plant and also generates compost for local farms, the lawsuit says.

Heartland’s plant, which became fully operational in November of 2015, emits a bad smell.

But the company has only exceeded odor limits established by its Weld County permit once, on April 27, it claims. Subsequently, Heartland spent millions of dollars on studies and new apparatus to reduce odors, according to the lawsuit. Although 800 tests have been performed by county and state officials since April, the plant never has exceeded limits set by the county’s operational permit, the lawsuit says.

Despite the company’s mitigation efforts, Weld County commissioners limited the facility’s gas production by 60 percent after a Sept. 19 hearing. On Nov. 10, Heartland entered a “compliance order and consent” deal, agreeing to abate “alleged odor concerns” by investing $3 million in smell mitigation equipment. The company has committed to go even further by spending $4.2 million, the lawsuit says.

The lawsuit filed by attorneys from the Denver law firm of Holland & Hart claims Weld County commissioners were just going through the motions when they convened the latest of a series of public hearings on the matter on Dec. 19.

That was obvious, the lawsuit says, when Commissioner Barbara Kirkmeyer opened the meeting by saying: “So, I’m curious as to why do I need to have any further public hearing or public testimony, or even any testimony whatsoever … I was wondering why I can’t make a motion right now to suspend.”

Kirkmeyer is on vacation and could not be reached for comment Wednesday.

The lawsuit says the outcome of the Dec. 19 hearing was predetermined.

Board members made an “arbitrary, irrational and hostile decision to suspend Heartland’s renewable energy operation,” the lawsuit says. Their decision was based on persistent complaints largely by 10 people who made 80 percent of all the complaints against the plant, the lawsuit says.