Fertilizer imports into the US, except for ammonia, sulfur and sulfuric acid, will remain exempt from the new 10pc tax proclamation President Donald Trump signed late last week.
Fertilizers exempted from the newly announced import tariffs effective 24 February include urea, ammonium nitrate, UAN, ammonium sulfate, TSP, DAP, MAP, MOP and SOP. Products included in the US-Mexico-Canada free trade agreement are also considered tariff free. But under Annex II of the proclamation, sulfur, sulfur acid and ammonia's HS codes are not exempt unless imported via the USMCA order.
Sulfur imports will likely remain unaffected by the new tariff because Canada is the only major foreign source of supply. About 72pc of sulfuric acid imports in 2025 came from Canada and Mexico, based on US Census Bureau data. Other origins, including Europe, Japan, and Taiwan are subject to 10pc tariffs. And 55pc of US ammonia imports came from Canada in 2025, with the rest largely coming from Trinidad and Tobago, which is also subject to a 10pc tariff.
Anhydrous ammonia was previously eligible for an exemption under the International Emergency Economic Powers Act (IEEPA) tariffs on a case-by-case basis by the secretary of commerce and the US Trade Representative, depending on the terms of existing or ongoing trade negotiations with each country. But case-by-case exemptions are not detailed in the new proclamation.
Trump in a social media post on 21 February threatened a 15pc tariff on all US imports, less than 24 hours after his administration unveiled the new 10pc global import tax set to go into effect on 24 February. But the White House has yet to formally release any record of the decision to raise the rate to 15pc.
Trump's proclamation of the new tariff on 20 February invokes Section 122 of the 1974 Trade Act, which allows imposing tariffs of up to 15pc to address a balance of payments issue. The policy was announced after the US Supreme Court deemed Trump did not have the power to impose tariffs under IEEPA against nearly all US trading partners.
The Section 122 tariffs will also exempt "natural resources and fertilizers that cannot be grown, mined, or otherwise produced in the US", according to a White House fact sheet. Trump's order also exempts beef, oranges, and tomatoes from the 10pc tariff.
But under the Section 122 declaration, tariffs can only be imposed for a period of 150 days, and any extensions would require explicit authorization from Congress.
Market reactions to the 10pc tariff policy were mostly muted across the fertilizer industry. Most buyers and sellers expected the exemptions to carry over after fertilizers were declared tariff-free in November 2025 from the original IEEPA tariffs. That assumption was also affirmed with the knowledge that phosphate and potash were recently deemed as critical minerals by the US Geological Survey.
