When President Trump announced tariffs on steel and aluminum imports this month, he said protecting the two industries was vital for national security.

"We want to build our ships. We want to build our planes. We want to build our military equipment with steel, with aluminum from our country," he said at a March 8 White House news conference.

In other words, the U.S. military should be as self-sufficient as possible, and not rely on other countries to supply the essential materials it needs for defense.

Erica Peterson

Add another export to the growing list of American products other countries could tax because of tariffs: met coal.

Metallurgical coal — or “met coal” — is low-ash, low-sulfur coal that’s used to produce coke, an essential fuel for steel-making.

Demand for met coal is tied to the demand for steel. It’s also an American export and a symbol President Donald Trump used often on the campaign trail to demonstrate how he would “Make America great again.”

J. Tyler Frankin

Gov. Matt Bevin was non-committal when asked what he thinks of President Donald Trump’s proposal to institute tariffs on foreign-made steel and aluminum.

The policy could benefit Kentucky aluminum manufacturers like Braidy Industries — the company that Bevin helped attract to the state with a package of economic incentives — and Century Aluminum, which announced it would hire 300 new workers in Hancock County if the tariff went into effect.

Flickr/Creative Commons/Pete Prodoehl

Century Aluminum Executive Vice President Jesse Gary said his company will begin hiring up to 300 new workers for its Hancock County smelter as soon as a proposed tariff order is signed.

President Trump is expected to announce a 10 percent tariff on aluminum and a 25 percent tariff on steel this week. Century Aluminum said its smelter in Hancock County could be back to full capacity by 2019 if the tariff order is signed.

Becca Schimmel

The Ohio Valley was once synonymous with steel. Even after the industry’s sharp decline the region is still home to many industries that produce or use steel and aluminum. Those industries are closely watching what the Trump administration will do on steel and aluminum imports.

The Department of Commerce has suggested a massive 24 percent global tariff on those imports. As a candidate, Donald Trump promised to apply tariffs. Now, it’s unclear if President Trump will follow through.