The threat of US levies on copper imports has been a boon for Freeport-McMoRan, with North America’s top producer cashing in on selling the metal at a premium. Still, the firm’s top boss warns that broader tariffs could hurt an industry President Donald Trump is trying to help.

“If global growth is disrupted, that could lead to an impact on copper prices,” CEO Kathleen Quirk said in an interview at Freeport’s Phoenix headquarters. “Ironically, if we’re trying to build up the US copper industry, slowing GDP growth and inflation could put a lot of pressure on mines here.”

A year into her CEO tenure, Quirk has found herself navigating a period of upheaval in the US copper industry. Trump has threatened to put tariffs on copper as he pushes to revive the domestic industry.

In late February the president directed the Commerce Secretary to open an investigation into foreign copper imports under Section 232 of the Trade Expansion act and submit a report within 270 days. The act gives the president broad authority to impose restrictions on national security grounds.

Levies threaten to inflict high costs across swaths of the American economy, since numerous industries and applications — including automobiles, consumer electronics and homebuilding — depend on the ubiquitous metal.

The tariff threat has driven copper prices in the US to levels above where the metal trades in other markets. Copper on New York’s Comex currently trades around 9.3% higher than prices on the London Metal Exchange, giving traders and producers an incentive to keep moving supplies to the US before any potential tariffs are imposed.

Freeport said in April when the premium was around 13% that such levels equal about $800 million in annual financial benefit to its copper sales. The company is responsible for about 70% of processed US copper, thanks to seven open-pit mines across the country and a smelter.

“We do benefit from having a copper tariff because it prices our copper higher domestically,” Quirk, 62, said in the May 29 interview. “If we have these big tariffs and trade wars, that makes us concerned for global demand for copper.”

Quirk said she’s “staying neutral” on copper duties, while recognizing both advantages and challenges if levies are imposed on metal imports. The impact of a tariff-fueled trade war could hurt demand for the metal that Freeport also produces in Indonesia, Spain, Peru and Chile, she said.

She supports efforts to revive the US copper industry and encourage more made-in-America production. Freeport has called for other incentives to boost copper mining in the US, like tax credits included in the Inflation Reduction Act that lithium and nickel miners are already eligible for.

Quirk joined Freeport in 1989, climbing the ranks before she was named chief financial officer in 2003 and then president in 2021. She worked for years alongside her predecessor, Richard Adkerson, who remains as chairman. Quirk inherited a firm that has grown into one of the world’s biggest copper producers, with mines across the globe. The company’s international operations, however, have faced setbacks, including a fire that sidelined a newly built copper smelter in Indonesia, that have weighed on the company’s stock.

Shares in Freeport have fallen about 14% since Quirk took over in June 11, following similar stock declines of other large copper miners including BHP Group, Teck Resources Ltd. and Southern Copper Corp.

Freeport is planning several expansions at its US assets, including extensions to a few Arizona mines, and is studying an expansion of its Miami smelter in the same state. But in a region where mines are older, grades are lower, and the cost to extend major operations in an already expensive region is burdensome, Quirk said the projects are “not barn-burners.”

It costs Freeport more than three times as much to churn out metal in the US than elsewhere, according to company presentations. The company generates greater profits on its mines in Indonesia and South America, where labor costs, energy prices and taxes are typically lower.

“The cost structure of the US is higher than it is globally,” Quirk said. “So if you want to protect this industry, you need to think about how to incentivize it.”