Methods of control. (1) Each port director shall establish controls and checks on the unlading and measurement of petroleum and petroleum products imported in bulk by vessel, truck, railroad car, pipeline, or other carrier. One of the following methods of control shall be employed:

Customs-approved metering and sampling installations provided by the importer;

Shore tank gauging; or

Weighing for trucks and railroad cars.

Vessel ullages shall be taken in every case unless the port director determines that it is impracticable to do so for safety or technological reasons. Ullages may be taken for trucks and railroad cars if weighing or shore tank gauging is not available as a method of control. Vessel ullages will not be used to determine the quantity unladen unless none of the other methods provided for in this paragraph is available or adequate.

The metering and sampling installations described in paragraph (a)(1)(i) of this section are approved by Customs on a case-by-case basis. Importers seeking approval shall send a complete description of the installation to the port director who, with the concurrence of the Director, Laboratory & Scientific Services, or his designee, shall give approval or shall state, in writing, the reasons for disapproval. Approved installations are subject to periodic verification by Customs. Importers desiring to modify a Customs-approved installation shall obtain Customs approval beforehand.

Duties of Customs officers. Customs officers may perform or witness ullaging and gauging as follows:

Opening ullages.

Closing ullages of carriers which have not completely discharged cargo, or if an importer or carrier requests Customs to witness closing ullages because of special problems.

Shore tank gauges performed by company or related-party employees.

Between 5 and 10 per cent of shore tank gauges conducted by commercial gaugers.

Shore tank gauges, including those conducted by a commercial gauger if no carrier ullages are taken.

Manifest discrepancies. Manifest discrepancies (shortages and overages) shall be reported by or on behalf of the carrier in the manner specified in § 4.12 of this chapter. If a reported discrepancy is not explained to the satisfaction of the port director, the master or other person in charge, or the owner of the vessel or vehicle, or any person directly or indirectly responsible for the discrepancy, will be subject to the imposition of the appropriate penalty under section 460, 584, or 592, Tariff Act of 1930, as amended (19 U.S.C. 1460, 1584, 1592).