Accepting comments from July 17, 2026, through August 17, 2026.
The Idaho Department of Environmental Quality (DEQ) seeks comment on a draft permit to construct revision for J.R. Simplot Company’s Don Siding Plant.
J.R. Simplot Company’s Don Siding Plant manufactures integrated phosphate fertilizer and other commercial products northwest of Pocatello, Idaho. The company is applying to revise its permit to construct (PTC) to remove the monthly phosphorous pentoxide (P2O5)
throughput limit in from the Granulation No. 3 Process and revise the annual P2O5 throughput limit to a rolling 12-month total. The Don Plant has three granulation plants that produce granulated phosphate fertilizers. The Granulation No. 3 Process can produce mono-calcium phosphate, di-calcium phosphate, or triple superphosphate. P2O5 is used in the defluorination process for mono- and dicalcium phosphate production.
DEQ has reviewed the application and completed an analysis of the information submitted by the applicant to remove the monthly P2O5 throughput limit from the Granulation No. 3 Process. Based on this analysis, DEQ proposes to issue the permit to construct to J.R. Simplot Company – Don Siding Pocatello.
The draft permit materials are available for public review at DEQ’s State Office (1410 N. Hilton St.) and below in related documents. Written comments on the draft permit and supporting materials will be accepted through August 17, 2026, at 5 p.m. MT. Submit comments using the form below or via mail or email to:
Dianne Hobbs
1410 N. Hilton St.
Boise, ID 83706
dianne.hobbs@deq.idaho.gov
For technical assistance on questions concerning this project or the permitting process, contact Nachammai Vairavan at (208) 373-0502 or nachammai.vairavan@deq.idaho.gov.
Related Documents
Permit Materials
Accessibility Services: The Idaho Department of Environmental Quality will provide reasonable language access services and/or disability services for documents at no charge. To request an accommodation under Title VI of the Civil Rights Act of 1964 or Americans with Disabilities Act, contact DEQ’s nondiscrimination coordinator at (208) 373-0271 or accessibility@deq.idaho.gov. Para obtener información en español, visite https://www.deq.idaho.gov/about-us/accessibility/.
Official Government Website
Updated at 1:45 p.m. MT on July 17, 2026: DEQ issued an Air Quality Advisory for 5 Idaho counties: Benewah, Bonner, Boundary, Kootenai, and Shoshone Counties, where all burning is prohibited. Take steps to protect your health and check DEQ’s air quality advisories map for future burn decisions.
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DEQ seeks comment on draft permit to construct revision for J.R. Simplot Company
Accepting comments from July 17, 2026, through August 17, 2026.
The Idaho Department of Environmental Quality (DEQ) seeks comment on a draft permit to construct revision for J.R. Simplot Company’s Don Siding Plant.
J.R. Simplot Company’s Don Siding Plant manufactures integrated phosphate fertilizer and other commercial products northwest of Pocatello, Idaho. The company is applying to revise its permit to construct (PTC) to remove the monthly phosphorous pentoxide (P2O5)
throughput limit in from the Granulation No. 3 Process and revise the annual P2O5 throughput limit to a rolling 12-month total. The Don Plant has three granulation plants that produce granulated phosphate fertilizers. The Granulation No. 3 Process can produce mono-calcium phosphate, di-calcium phosphate, or triple superphosphate. P2O5 is used in the defluorination process for mono- and dicalcium phosphate production.
DEQ has reviewed the application and completed an analysis of the information submitted by the applicant to remove the monthly P2O5 throughput limit from the Granulation No. 3 Process. Based on this analysis, DEQ proposes to issue the permit to construct to J.R. Simplot Company – Don Siding Pocatello.
The draft permit materials are available for public review at DEQ’s State Office (1410 N. Hilton St.) and below in related documents. Written comments on the draft permit and supporting materials will be accepted through August 17, 2026, at 5 p.m. MT. Submit comments using the form below or via mail or email to:
Dianne Hobbs
1410 N. Hilton St.
Boise, ID 83706
dianne.hobbs@deq.idaho.gov
For technical assistance on questions concerning this project or the permitting process, contact Nachammai Vairavan at (208) 373-0502 or nachammai.vairavan@deq.idaho.gov.
Related Documents
Permit Materials
Accessibility Services: The Idaho Department of Environmental Quality will provide reasonable language access services and/or disability services for documents at no charge. To request an accommodation under Title VI of the Civil Rights Act of 1964 or Americans with Disabilities Act, contact DEQ’s nondiscrimination coordinator at (208) 373-0271 or accessibility@deq.idaho.gov. Para obtener información en español, visite https://www.deq.idaho.gov/about-us/accessibility/.
Public Comment Form