A bill to amend the Internal Revenue Code of 1986 to provide that the harbor maintenance tax shall apply only once to cargo entering the United States in a continous transportation by a single shipper.

Amends the Internal Revenue Code with respect to cargo that has entered the United States and on which the importer has paid the harbor maintenance (port) tax. Prohibits the imposition of tax with respect to any subsequent loading or unloading of the same cargo if: (1) the shipper is the same at the time of entry and at the time of the subsequent loading or unloading; and (2) the subsequent activity is in connection with the continuous transportation of the cargo to its ultimate U.S. destination.