The department said it will look into whether the 18 countries were unfairly dumping the products in the U.S. market and whether exports from four of the nations were being unfairly subsidized. If the department finds aluminium sheet imports from any of the countries are unfairly dumped or subsidized, and a separate trade panel finds that domestic producers are being injured, the United States would place tariffs on the products.

(Reporting by Mohammad Zargham; Writing by Tim Ahmann; Editing by Leslie Adler)