Sulphur from Canada, which is by far the US' largest supplier, is not expected to be covered by the sweeping tariffs announced by President Donald Trump on 2 April.
US sulphur imports from Canada totalled 830,000t in 2024 according to the US Geological Survey, with the rest of the world supplying just 60,000t.
Trump exempted many energy and mineral products from tariffs unveiled on 2 April.
Sulphur was not on the list of exemptions, but is understood to be covered by the US-Mexico-Canada free trade agreement, so should continue to be imported without tariffs.
Sulphur imports from countries other than Canada and Mexico are believed to be subject to a 25pc tariff.
US sulphur consumers would face higher prices if Canadian flows are subject to tariffs at a later date.
Trump has threatened Canada and Mexico with further tariffs. He briefly imposed a 25pc levy on sulphur from Canada in February, only to suspend this days later.
