19 U.S.C. § 1449

Except as provided in sections 1442 and 1447 of this title (relating to residue cargo and to bulk cargo respectively), merchandise and baggage imported in any vessel by sea shall be unladen at the port of entry to which such vessel is destined, unless (1) such vessel is compelled by any cause to put into another port of entry, and the Customs Service issues a permit for the unlading of such merchandise or baggage at such port, or (2) the Secretary of the Treasury, because of an emergency existing at the port of destination, authorizes such vessel to proceed to another port of entry. Merchandise and baggage so unladen may be entered in the same manner as other imported merchandise or baggage and may be treated as unclaimed merchandise or baggage and stored at the expense and risk of the owner thereof, or may be reladen without entry upon the vessel from which it was unladen for transportation to its destination.