DES MOINES, Iowa (AP) — An Iowa egg farm that killed millions of chickens because of a 2015 bird-flu outbreak is suing companies hired by the federal government to disinfect barns.

Sunrise Farms stated the chlorine-dioxide gas and heat treatments used to kill the virus destroyed barn equipment, electrical wiring, production equipment and water lines. The company also stated the structural integrity of its barns was diminished.

Max Barnett, the CEO of Sunrise Farms’ parent company, South Dakota-based Sonstegard Foods, said he couldn’t comment on a pending court case.

The farm is near the northwest-Iowa town of Harris. It includes a feed mill, 25 layer barns, two manure barns and a processing plant. The barns housed 4 million egg-laying hens. Two other buildings had 500,000 young hens being raised to become layers.

The farm confirmed April 19, 2015, that its birds had the deadly strain of H5N2 bird flu. Officials from the U.S. Department of Agriculture’s Animal and Plant Health Inspection Service division arrived within days. They took over the cleanup and disinfection process, hiring several companies to complete euthanizing birds and disinfecting barns to prevent the spread of the virus.

In the 2015 U.S. bird-flu outbreak more than 50 million chickens and turkeys died or were destroyed. That comprises about 12 percent of hens that produce eggs people eat and 8 percent of the inventory of turkeys grown for meat, according to the USDA.

About 87 percent of bird losses occurred in Iowa, the nation’s leading egg producer, and Minnesota, the leading turkey grower. Other cases were reported in Nebraska, Wisconsin and South Dakota.

The heat treatment used at some of the Sunrise Farms barns was designed to increase the temperature to 120 degrees for a period of seven days. In other barns the government officials ordered the use of chlorine dioxide, a chemical known to kill the flu virus.

The barns were declared free of virus and eligible for restocking Sept. 16, 2015. But court documents state the treatments destroyed equipment, electrical wiring and water lines, and left the barns’ structural integrity diminished. Sunrise Farms claims its property damage required extensive repairs.

The company filed the lawsuit in March 2018 in federal court in Iowa, seeking to be repaid for the cost of repairs, interest, late charges and the cost of the lawsuit. It claims negligence for causing significant property damage and breach of contract, stating the contracted companies “failed to adequately perform the contract obligations.”

The lawsuit names Clean Harbors Environmental Services of Norwell, Massachusetts, and other companies based in Georgia and New York.

In court documents Clean Harbors, which applied the chlorine-dioxide-gas treatment, denied responsibility for the damage and asked that the lawsuit be dismissed. The company said Sunrise Farms “failed to adequately and properly mitigate its damages.”

Clean Harbors is suing six other companies that were contracted to assist in the operation. One of those companies is suing seven other companies with which it had contracted. A lawyer representing Clean Harbors didn’t respond to a message.

The lawsuit is set for trial Jan. 27, 2020, in Sioux City.

Another major egg producer with barns in Iowa and other states also used the heat treatment for disinfection after the bird flu. He said he saw some damage but determined the equipment was older and needed to be replaced anyway.

Marcus Rust, CEO of Rose Acre Farms, the nation’s second-largest egg producer, said his company was satisfied with its outcome. He said he’d heard about the problems at Sunrise Farms and was uneasy, but determined that the effectiveness of the gas treatment was better than any other alternative.

“Did we have zero problems? No,” he said. “But has it been acceptable? Yes. We were apprehensive and maybe we watched it a lot closer because of all the warnings.”

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