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.

The 50% tariffs on steel and aluminum apply to all countries, except the United Kingdom, which announced a preliminary trade deal with the Trump administration in May. The rate for steel and aluminum imports from the U.K. remains at 25% until at least July 9.