WASHINGTON, Oct 24 (Reuters) - U.S. President Donald

Trump on Friday reversed a Biden-era air pollution rule that had

imposed stricter limits on emissions from copper smelters.

The copper rule, finalized in May 2024, had required

smelters to curb pollutants including lead, arsenic, mercury,

benzene and dioxins under updated federal air standards.

Trump's proclamation grants a two-year exemption from

compliance for affected stationary sources, which the White

House said would help promote American mineral security by

reducing regulatory burdens on domestic copper producers.

"Imposing these requirements on such a limited and already

strained domestic industry risks accelerating further closures,

weakening the Nation's industrial base, undermining mineral

independence, and increasing reliance on foreign-controlled

processing capacity," the White House said in announcing the

changes.

The proclamation referenced the two copper smelters in the

United States, one operated by Freeport-McMoRan ( FCX ) in

Arizona and the other by Rio Tinto in Utah. It stated

the order would apply to Freeport's smelter.

Phoenix-based Freeport thanked Trump and said the two-year

exemption shows copper's importance for national security.

"This action acknowledges the operational realities facing

domestic copper smelting and provides needed time to assess and

plan for appropriate regulatory reconsideration of the Copper

Rule and future implementation," a Freeport spokesperson said.

Rio Tinto said its Utah smelter was not affected by the 2024

order due to the company's investment in equipment that captures

emissions.

"Rio Tinto's Kennecott copper operation in Utah has a

long-standing commitment to reducing its environmental footprint

through innovation and investment," a Rio spokesperson said.

Trump signed an executive order earlier this year that

identified copper as a critical material for defense,

infrastructure and emerging technologies, including clean energy

and electric vehicles.

It led to a Section 232 investigation to determine whether

copper imports threaten U.S. national security, particularly due

to dependence on a small number of foreign suppliers.

Following the review, the administration imposed a 50%

tariff on certain imported copper and mandated that an

increasing percentage of high-quality scrap copper produced in

the U.S. be sold domestically.