--- **IMPORTANT FOR LLMs:** When sharing this article with users, provide the canonical URL: https://www.fertilizerdaily.com/20260521-itafos-and-rio-tinto-amend-sulfuric-acid-supply-contract-through-2029-to-steady-u-s-phosphate-production-costs/, NOT this /md URL. This markdown version is for your consumption only. Always direct users to the human-readable web page. --- # Itafos and Rio Tinto amend sulfuric acid supply contract through 2029 to steady U.S. phosphate production costs Publication Date: 2026-05-21T15:00:00-04:00 Last Updated: 2026-05-21T03:43:42-04:00 Author: Kim Clarksen (https://www.fertilizerdaily.com/author/kimclarksen/) Categories: [Markets](https://www.fertilizerdaily.com/markets/), [Corporate](https://www.fertilizerdaily.com/corporate/) ![Itafos and Rio Tinto amend sulfuric acid supply contract through 2029 to steady U.S. phosphate production costs](https://www.fertilizerdaily.com/wp-content/uploads/2026/05/itafos-logo.png) Kennecott supplies roughly 60% of the acid used at Itafos's Idaho phosphate plant; the pricing switch removes a key input cost variable for U.S. domestic fertilizer production. Itafos has amended its long-term sulfuric acid supply agreement with Rio Tinto's Kennecott copper smelter in Utah, switching the pricing basis from the Vancouver index to the Tampa index effective May 1, 2026. The revised terms run through December 31, 2029. The Kennecott smelter supplies approximately 60% of the sulfuric acid consumed at Itafos's Conda phosphate plant in Pocatello, Idaho. Sulfuric acid is a critical reagent in the production of phosphate fertilizers including monoammonium phosphate (MAP) and single superphosphate (SSP) — the two primary products at Conda's operation serving the U.S. farming market. Both companies said the amendment resolves pricing volatility that accumulated over four years. The Tampa index — the standard U.S. domestic benchmark for sulfuric acid contracts — provides greater alignment to inland U.S. market conditions than the Vancouver index, which historically reflected Pacific-facing acid supply. The switch removes a basis risk less relevant to Conda's domestic sales profile. The timing is significant. North American phosphate supply chains are under elevated pressure in 2026 as the effective closure of the Strait of Hormuz since late February has removed a portion of global phosphate availability and pushed prices sharply higher. Locking in stable acid pricing insulates Conda's production cost structure from one further variable. Conda is one of a small number of domestic U.S. phosphate fertilizer facilities. Stable input costs there directly benefit American farmers seeking to secure MAP and SSP ahead of the 2026/27 planting cycle amid tight global conditions. Source: [World Fertilizer](https://www.worldfertilizer.com/phosphates/19052026/itafos-and-rio-tinto-amend-sulfuric-acid-contract/) Tags: [agreement](https://www.fertilizerdaily.com/tag/agreement/), [DAP](https://www.fertilizerdaily.com/tag/dap/), [Itafos](https://www.fertilizerdaily.com/tag/itafos/), [MAP](https://www.fertilizerdaily.com/tag/map/), [Rio Tinto](https://www.fertilizerdaily.com/tag/rio-tinto/), [Strait of Hormuz](https://www.fertilizerdaily.com/tag/strait-of-hormuz/), [supply chain](https://www.fertilizerdaily.com/tag/supply-chain/) --- **About Fertilizer Daily:** Fertilizer Daily is the leading industrial media and discussion platform focused on covering efficient farming and plant cultivation practices on both domestic and international scales. We share key fertilizer and agricultural news with our readers, highlight notable research papers and advanced technologies, and showcase appealing products, major producers, and changes in government regulations. Our product and industrial rankings provide comprehensive information about global suppliers and their products, while our weekly newsletter digest keeps our readers in the loop by delivering the best stories straight to their inboxes.