Washington, July 31
US President Donald Trump has signed a proclamation to address the effects of copper imports, imposing universal 50 per cent tariffs on imports of semi-finished copper products and copper-intensive derivative products, effective on August 1.

The proclamation directs the US secretary of commerce to establish a product "inclusion" process to add copper derivative products to these tariffs, and the president is authorising the secretary of commerce to take steps under the Defence Production Act to support the domestic copper industry, the White House said in a fact sheet on Wednesday.

"By taking these actions, President Trump is levelling the playing field for US copper businesses to support a strong domestic copper industry," the White House added.

Copper is essential to the manufacturing foundation on which US national and economic security depend, and is a necessary input in a range of defence systems, including aircraft, ground vehicles, ships, submarines, missiles and ammunition, according to the fact sheet, reports Xinhua news agency.

US copper futures on Comex plunged 20 per cent after the announcement, Bloomberg reported. Until Wednesday afternoon, US copper prices had been trading around 28 per cent above benchmark copper futures on the London Metal Exchange, as traders anticipated the tariff would be applied to all refined metal imports.

The decision is the latest surprise from Trump to upend the copper market, Bloomberg said in its report. When the president first flagged the likelihood of tariffs early this year, he triggered a surge in US copper prices relative to the rest of the world and set off a race to ship copper to the United States to beat the tariffs, delivering substantial profits to some of the world's biggest metals traders.

Trump orders universal 50 pct tariff on imports of certain copper products