The United States is highly reliant on steel imports, bringing in more of the material from abroad than any other country in the world, according to the International Trade Administration. More than 26 million metric tons of steel were imported last year, most of which came from Brazil, Canada, Mexico, South Korea, and China.

President Trump has doubled the rate on foreign metals to 50%, saying the levies weren’t high enough to help the U.S. industry.

President Trump’s 50% tariff on steel and aluminum takes effect June 4, but legal fights over tariffs could end up at the Supreme Court.