A South Korean steel product has been exempted from U.S. tariffs for the first time since Washington imposed an import quota on South Korean steel in May.

According to industry sources Thursday, the U.S. Commerce Department on Monday accepted a request from American medical equipment maker Micro Stamping to exclude superfine stainless steel tubes made by South Korea's SL Tech.

It marks the first exemption since May when America set a yearly import quota of two-point-63 million tons for South Korean steel products, or 70 percent of their average export volume over the past three years. 

The U.S. exempts imported goods from tariffs when domestic production is not sufficient to meet demand.