SOUTH SIOUX CITY | Three South Sioux City homeowners have sued the city and Big Ox Energy for more than $2.2 million in damages, claiming odors and hazardous gases from the bioenergy plant have made their property worthless and damaged their health.

Jonathan and Betty Goodier, David and Maria DeLeon and Michael and Jacqueline Klassen all filed suits within the past week in Dakota County District Court, saying that their homes near the plant have been "reduced to waste because of fowl, offensive and deleterious and dangerous chemicals and chemical odors pervading it and permanently destroying it."

All three lawsuits said that Big Ox and the city failed to maintain, operate and modify wastewater treatment facilities and sewer systems to handle waste from the plant and prevent the release of hydrogen sulfate and other toxic gases.

All three families said that as a result of those gases and odors, they suffer from health problems including respiratory illnesses, headaches, nausea, sleep disturbances, anxiety and emotional distress.

The lawsuits allege that Big Ox and the city knew or should have known after initial tests of the plant's operations in August 2016 that the municipal sewer system "would be overwhelmed and unable to handle the pressures and substances forced into it." As a result, the lawsuits say, gases escaped through manholes and into residences near the plant.

Big Ox denies the allegations and will defend itself against the claims, the company said in a released statement.

"Big Ox Energy has proactively worked with all interrelated federal, state and local agencies and with the residents and leadership of South Sioux City to ensure that its highly regulated operations have not and will not cause any adverse impacts to the safety or health of the local community," the company said in the statement.

The company complies with all regulations included in its air and water permits and said the lawsuits' claims that it concealed the contents of the released gases are "unequivocally false."

The three owners are seeking damages to reimburse for loss of use of their homes, demolition and reconstruction of their houses and loss of furnishings ruined by odors.

The Goodiers estimate property damages at $800,000, the Klassens list damages at $799,500 and the DeLeons' damages total $658,250. Costs continue to accrue, the lawsuits said.

Big Ox Energy's more than $30 million plant uses an anaerobic digestion process to extract organic nutrients from animal, grain and other waste to create methane, which is then sold into the natural gas pipeline. The plant went online Sept. 2, 2016, in the Roth Industrial Park.

Residents began reporting putrid odors from the plant in mid-October, when sewer gas permeated some homes in a five-block area of Red Bird Lane and Le Mesa Way, along 39th Street, both indoors and outdoors.

Many residents blamed the plant for causing the issues in the line the residents and the plant, at the time, shared.

The families were displaced from their homes for months because of the odors, and some families have yet to return home. The city and Big Ox have spent hundreds of thousands of dollars to cover displaced homeowners' relocation and living expenses while living in temporary housing. The city in August filed a federal lawsuit against two insurance companies that have not covered the claims filed by homeowners. That suit is pending.

Big Ox maintains that faulty plumbing, not wastewater, was the primary cause of the odor issues in South Sioux City, citing a study that showed hydrogen sulfide had generally not entered homes that had plumbing systems in compliance with building codes.

The city has since spent more than $1.5 million on sewer upgrades and modifications.

In May, 16 families and one business filed political subdivision tort claims against the city, detailing $35 million in alleged property damages and personal injuries resulting from exposure to the potentially deadly fumes. State law required them to wait at least six months to sue the city.

On Tuesday, the U.S. Environmental Protection Agency announced that Big Ox will pay nearly $50,000 as part of a settlement for alleged violations of the federal Clean Air Act. That action related to the release of chemical gases that led to the hospitalization of an employee who was injured at the plant in December.

The EPA on Tuesday said that hydrogen sulfide associated with the plant entered the city sewer system, leading to the displacement of 26 households last fall. A company representative said the EPA has not alleged in its settlement with the Denmark-Wisconsin-based company that hydrogen sulfide gas infiltrated the homes.

The company also was fined more than $60,000 earlier this year after settling three citations from the Occupational Safety and Health Administration that detailed a lack of protection, education and safety practices for employees, which at times left employees vulnerable to hazardous gases inside the facility.

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