US tariffs encourage aluminium manufacturing, but Oklahoma smelter faces opposition

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The US' push to rebuild its domestic aluminium industry has been underway for years, with tariffs playing a central role in the strategy. But as Washington tries to attract new smelting investment, opposition to a major proposed project in Oklahoma is raising questions about how easily the country can expand its aluminium capacity.

The Section 232 tariffs, introduced in March 2018, were aimed at reducing US dependence on imported aluminium, which the government viewed as a national security risk. The policy also sought to revive idle smelters, attract new investment and strengthen the domestic supply chain.

The policy was tightened in 2025, when the US raised aluminium tariffs to 50 per cent for imports from most countries, giving greater protection to domestic producers.

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New investment in aluminium smelting is already emerging from this policy environment. Century Aluminum and Emirates Global Aluminium (EGA) announced plans earlier this year to build a new aluminium smelter in Oklahoma, which would be the first new US smelter in decades.

President Donald Trump publicly backed the project in April, saying “I went there, and I got them to invest USD 1 trillion in the United States, and they are building a tremendous plant in a great state called Oklahoma.” Trump further added, “It will be the best anywhere in the world. They are very good for this country.” 

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But the project has also faced opposition. Oklahoma Attorney General Gentner Drummond filed a state lawsuit in June seeking to block construction, citing concerns over pollution, public health, livestock and natural resources. He has also questioned the project's foreign ownership.

The dispute has become a major issue in Oklahoma's Republican gubernatorial race. Mike Mazzei, who had initially criticised the project's links to UAE-backed companies, later endorsed the smelter after Trump publicly backed it. Drummond has taken the opposite position, although he has recently indicated that additional information regarding the project could influence his stance.

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Century Aluminum is also expanding its Mt. Holly smelter in South Carolina, a move expected to lift its total US primary aluminium production by nearly 10 per cent and add around 150 jobs. CEO of the company Jesse Gary said, “President Trump is again prioritising America first by making it easier to make investments like Oklahoma Primary Aluminium.“ 

However, the Inola debate highlights the challenge faced by the US aluminium strategy. While tariffs can support domestic production, new smelters still need major investment, permits and local support. The outcome of Inola could show how far the US can go in rebuilding its aluminium capacity.