Pocatello, Idaho-The Idaho Department of Environmental Quality has requested more information from the J.R. Simplot Co. regarding the company’s application for a modified air quality permit. The permit would remove productions limits at one of the company’s two sulfuric acid plants near Pocatello, where it manufactures fertilizer. Simplot’s Don Plant discharges about 565 tons of sulfur dioxide annually. Simplot anticipates that would increase to 602 tons if the sulfuric acid production limit were removed, but still be well below the 750 tons allowed each year under federal standards. Although it was anticipated that sulfur dioxide, nitrous oxide, sulfuric acid mist, and particulate emissions would increase, the IDEQ issued a draft Permit to Construct (PTC) on March 26 after determining modifications would not result in violating air quality standards or unreasonably impacting people, animals, or vegetation. A public informational hearing was held on May 21, with a public comment period from April 8 and June 10. At the public hearing, some citizens criticized Simplot’s proposal and IDEQ’s regulation of the company’s phosphate fertilizer complex. Actual emissions of PM10 are now estimated at 8.17 pounds per hour. Simplot estimates if output limits are removed, emissions would not exceed 11.25 pounds per hour or 49 tons per year of PM10, and that the nitrous oxide emission rate would be reduced from 64 tons per year to 58 tons per year. Simplot’s two sulfuric acid plants have been subject to a standard of sulfur dioxide emissions at four pounds per ton of 100 percent sulfuric acid produced. In June 2006, Simplot submitted its permit to construct modification application requesting removal of a 1,750-tons-per-day production limit for the No. 300 sulfuric acid plant. It estimates it would produce 2,000 tons per day without the restriction. The Don Plant manufactures two concentrations of sulfuric acid ?Çô 93 percent during the winter and 98 percent during the summer. IDEQ wants Simplot to determine if the expansion in sulfuric acid production would significantly increase particulate, sulfur dioxide, nitrous oxide, or sulfuric acid emissions, and by how many tons per year, and to identify and describe processes at each boiler, superheater, or similar apparatus associated with the sulfuric acid plant. Actual ammonia emissions from the sulfuric acid plant’s stack also must be determined. Simplot must submit the requested information within 60 days of receiving the letter. After reviewing Simplot’s response, IDEQ will either take final action on the application or revise the proposed permit and call for a second public comment period.
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