It was reported that the United States has launched an investigation into the possible national security threat posed by imports of titanium sponge, a product widely used in the aerospace industry that the United States buys mainly from Japan.

In 2017, the United States imported US$208 million worth of titanium sponge, with 86% coming from Japan. The move, announced on Monday by the United States Department of Commerce (USDOC), could be a new sore point between the United States and Japan.

The two major producers of sponge titanium in Japan, Toho Titanium and Osaka Titanium, shares fell 3% on the Tokyo exchange after the news. The two countries are preparing to begin formal negotiations on a potential trade agreement.