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U.S. Aluminum Smelters Stage Comeback as Tariffs Lift Domestic Output
U.S. primary aluminum production is showing signs of revival after decades of contraction, with Century Aluminum restoring idled capacity and Magnitude 7 Metals preparing to restart its Missouri smelter. An industry-backed economic analysis argues that higher Section 232 tariffs are helping improve domestic smelter economics, although environmental and legal challenges remain around several projects.
Key Points
- U.S. output: The United States now accounts for roughly 1% of global primary aluminum production, far below its position at the start of the century.
- Mt. Holly: Century Aluminum has restored its South Carolina smelter to full production following a $50 million investment.
- Missouri: Magnitude 7 Metals plans to restart part of its Marston smelter before the end of 2026.
- Tariffs: Section 232 aluminum tariffs were raised to 50% in 2025 and were broadened in April 2026 to apply to the full customs value of covered products.
- Oklahoma: A proposed $4 billion smelter in Inola remains subject to litigation, environmental review and a local development moratorium through April 2027.
SEATTLE (Scrap Monster): The U.S. primary aluminum industry is showing early signs of renewed investment after decades of shrinking domestic capacity, with producers restarting idled smelting operations and pursuing what could become the country's first new primary aluminum smelter in more than four decades.
An economic analysis presented by Adam Hersh, a research fellow at the University of Massachusetts, argues that U.S. aluminum production has become a strategic vulnerability as domestic smelting capacity declined while China and other regions expanded rapidly.
Hersh presented the study during an event sponsored by the American Primary Aluminum Association.
U.S. Aluminum Capacity Has Fallen Sharply Since 2000
In 2000, the United States accounted for roughly 15% of global primary aluminum capacity, according to Hersh's analysis, with 23 smelters operating nationwide.
Today, the country produces only about 1% of the world's primary aluminum and has just a small number of operating smelters owned principally by Alcoa and Century Aluminum.
The long decline reflects a combination of high electricity and operating costs, aging infrastructure and increasing competition from lower-cost foreign production.
China, by contrast, has added nearly 42 million metric tonnes of aluminum capacity over the past 25 years, according to the study.
High-Purity Aluminum Raises National-Security Concerns
The decline is particularly important for high-purity aluminum used in military, aerospace, energy and transportation applications.
Hersh said the United States currently lacks a domestic smelter capable of producing certain high-purity aluminum grades required for military applications.
That leaves U.S. manufacturers dependent on foreign suppliers for material that has relatively few substitutes in aircraft, armored vehicles, electrical infrastructure and other strategic uses.
Section 232 Tariffs Reshape Domestic Aluminum Economics
The Trump administration increased Section 232 tariffs on imported aluminum and steel from 25% to 50% in June 2025.
The tariff system was revised again in April 2026. For covered aluminum articles, the additional duties are now assessed against the full customs value of the imported product rather than only the aluminum content in many cases.
Supporters of the policy argue that the changes reduce opportunities to circumvent the tariffs and improve the economics of domestic smelting.
Hersh's analysis concluded that the measures have helped lift domestic aluminum pricing and encouraged producers to restore idled capacity.
His study also found little or no measurable price effect in several downstream product categories examined, including beer cans, wire and cable, construction materials and furniture.
That conclusion remains the author's economic assessment rather than a universal finding across all aluminum-consuming industries.
Century Aluminum Restores Mt. Holly to Full Production
Century Aluminum has already expanded domestic output at its Mt. Holly smelter in South Carolina.
The company invested approximately $50 million to restart previously idled capacity, adding roughly 50,000 metric tonnes of annual production.
Mt. Holly has capacity to produce approximately 230,000 metric tonnes per year and has now returned to full operating capacity.
Century estimates the restart increases total U.S. primary aluminum production by roughly 10%.
Magnitude 7 Plans Missouri Smelter Restart
Magnitude 7 Metals is also preparing to restart its aluminum smelter in Marston, Missouri, after the facility curtailed operations in 2024.
The company plans to restart one potline before the end of 2026, adding approximately 75,000 tons of annual primary aluminum capacity.
The restart could restore hundreds of manufacturing jobs in southeast Missouri.
The facility also carries an environmental history that will remain important as production resumes.
Before the plant shut down, air monitoring in the surrounding area showed sulfur dioxide concentrations above the federal one-hour standard. Missouri environmental regulators have said monitoring and compliance oversight will continue following the restart.
$4 Billion Oklahoma Smelter Faces Legal and Local Opposition
Century Aluminum and Emirates Global Aluminum are separately pursuing a proposed $4 billion primary aluminum smelter in Inola, Oklahoma.
If completed, the project would be the first new U.S. primary aluminum smelter built in more than 40 years and could more than double current domestic output.
The federal government has committed up to $500 million in support for the project, citing its potential national-security importance.
The development has also faced strong opposition from some local residents and Oklahoma Attorney General Gentner Drummond, who has challenged the project over environmental and ownership concerns.
The U.S. Justice Department has filed in support of the smelter developers, arguing that existing federal environmental permitting processes are the appropriate mechanism for evaluating environmental risks.
Inola Moratorium Runs Through April 2027
Local development approvals remain another obstacle.
Inola's town council extended a moratorium on heavy industrial development and primary aluminum smelting through April 7, 2027.
Residents are also scheduled to vote in April on a proposed ordinance that would prohibit primary aluminum smelting within the town limits.
Legal challenges involving the project, local restrictions and the Tulsa-Rogers County Port Authority remain possible.
ScrapMonster Market Read
U.S. primary aluminum is moving through its most significant period of capacity rebuilding in years, but the recovery remains early and highly dependent on policy, power costs and project execution.
Mt. Holly's return to full production provides tangible additional supply, while the planned Missouri restart could add further output before year-end.
The much larger Oklahoma project would change the domestic supply picture more substantially, but its legal, environmental and local-government challenges make its timing less certain.
For recyclers and secondary aluminum producers, stronger primary production does not eliminate the importance of scrap. Higher domestic manufacturing activity can increase both aluminum demand and the generation of new industrial scrap, potentially expanding the role of recycled metal alongside primary supply.
Source reporting: Manufacturing Dive and American Primary Aluminum Association.
