SOUTH SIOUX CITY -- Big Ox Energy's renewable energy plant contributed to toxic odors that endangered the public and violated the federal Clean Air Act, the Environmental Protection Agency said in a document.
In a "letter of warning" to Big Ox, the EPA Region 7 in Kansas City said its investigators during a Jan. 10-12 inspection found that "discharges of pollutants from Big Ox, alone or in conjunction with other sources, resulted in the creation of toxic gases, vapors, or fumes ... in quantities that could cause worker health and safety problems, in violation" of national pretreatment standards.
In the letter, dated Oct. 4, the EPA said it is forwarding its findings to the Nebraska Department of Environmental Quality to consider any penalties. The NDEQ is taking the lead on the Clean Air Act probe, the federal agency noted.
Noxious fumes from sewer lines forced more than two dozen families from their homes last year. The putrid odors began in mid-October when sewer gas permeated the homes in a five-block area of Red Bird Lane and Le Mesa Way, along 39th Street, both indoors and outdoors.'
Many residents blamed Big Ox's plant, which went online Sept. 2 in the city's Roth Industrial Park, for causing the issues in the line the residents and the plant, at the time, shared. The plant turns industrial waste into methane for sale to a natural gas pipeline.
Almost all residents said they suffered from nausea, headaches, sleep disturbance, emotional distress and other effects. Some residents said they had visited the hospital for their symptoms, sometimes multiple times.
Several of the residents have started taking legal action against the city of South Sioux City and have mentioned Big Ox will also be the subject of future legal action.
Big Ox in January had denied culpability for the sewer gases, saying other industries have also affected the hydrogen sulfide levels in the sewer lines and that individual plumbing deficiencies in many of the affected homes played a major role. South Sioux City's administration has largely aligned with Big Ox Energy's assessment.
Big Ox spokesman Kevin Bradley could not immediately be reached for comment Tuesday night.