SOUTH SIOUX CITY -- State regulators have cited Big Ox Energy for leaks found in a damaged section of the South Sioux City biofuels plant.
The notice of violation, issued Monday by the Nebraska Department of Environmental Quality, cites Big Ox for failing to control emissions from units requiring control equipment, a violation of state air quality regulations.
Inspectors during a March 28 visit to the plant observed damage to the south anaerobic digester structure, which was leaking uncontrolled emissions that likely included methane, hydrogen sulfide and other volatile organic compounds, said Kevin Stoner, administrator of the NDEQ's Air Quality Division. Stoner said inspectors did not determine how long the gases had been leaking.
The NDEQ has asked Big Ox to submit a written assessment of the damage and a schedule for repairs within the next two weeks. The violation is under NDEQ consideration for further enforcement action, which could include civil actions such as fines. Stoner said the department has yet to decide if further actions will be taken.
Big Ox spokesman Kevin Bradley did not immediately return messages seeking comment.
The NDEQ has issued notices of violation to Big Ox for air quality violations on July 23, Aug. 16 and Nov. 7 in 2018 and storm water and pollutant discharge permit violations on June 20, 2018. A storm water permit violation was sent to Big Ox on Jan. 7.
The U.S. Environmental Protection Agency also has issued notices of noncompliance, findings of violations, administrative compliance orders or warning letters to the company four times from Oct. 4, 2017, to Feb. 8.
In March, the NDEQ ordered Big Ox to appear for a May hearing to justify why its state air quality and storm water permits should not be revoked because of its past violations.
The Wisconsin-based company, which converts organic waste from local industries to methane, has had problems with repeated venting of hydrogen sulfide gas into the atmosphere and solid waste spills, some of which have run off the company's property. The company also has been cited for storing solid waste on its grounds outside the plant.
Since Big Ox began operations in September 2016, it has been the subject of numerous odor complains from South Sioux City residents living near the plant. A class action lawsuit has been filed against the company claiming that its odors are a nuisance and the result of negligence. A total of 15 homeowners have filed individual lawsuits against the company, claiming that toxic odors and gases backed up into their homes shortly after the plant began operations, causing health issues and making their homes uninhabitable.