19 U.S.C. § 1626
In order to monitor and enforce export measures required by a foreign government or customs union, pursuant to an international arrangement with the United States, the Secretary of the Treasury may, upon receipt of a request by the President of the United States and by a foreign government or customs union, require the presentation of a valid export license or other documents issued by such foreign government or customs union as a condition for entry into the United States of steel mill products specified in the request. The Secretary may provide by regulation for the terms and conditions under which such merchandise attempted to be entered without an accompanying valid export license or other documents may be denied entry into the United States.
This section applies only to requests received by the Secretary of the Treasury prior to January 1, 1983, and for the duration of the arrangements.
19 U.S.C. § 1626