Small and medium-sized American companies are suffering the most from the higher supply costs created by President Trump’s tariffs, and a tool meant to help them cope is instead aggravating the pain.

In late March, the U.S. Department of Commerce told businesses they could begin submitting requests for the government to exclude specific products or raw materials from double-digit tariffs, a process designed to avoid imposing undue costs on specific types of steel and aluminum products that can’t be found in the domestic market.