19 CFR 18.21 - Restricted and prohibited merchandise.
(a) Merchandise subject upon importation to examination, disinfection, or further treatment under quarantines and Quarantine Division, Agricultural Research Service, Department of Agriculture, shall be released for transportation or exportation only upon written permission of, or under regulations issued by, that Bureau. (See §§ 12.10 to 12.15 of this chapter.)
(b) Narcotics and other articles prohibited admission into the commerce of the United States shall not be entered for transportation and exportation and any such merchandise offered for entry for that purpose shall be seized, except that exportation or transportation and exportation may be permitted upon written authority from the proper governmental agency and/or compliance with the regulations of such agency.
(c) Articles in transit manifested merely as drugs, medicines, or chemicals, without evidence to satisfy the port director that they are non-narcotic, shall be detained and subjected, at the carrier's risk and expense, to such examination as may be necessary to satisfy the port director whether or not they are of a narcotic character. A properly verified certificate of the shipper, specifying the items in the shipment and stating whether narcotic or not, may be accepted by the port director to establish the character of such a shipment.
(d) Explosives shall not be entered for transportation and/or exportation under a transportation and exportation entry, or an immediate transportation entry unless the importer has first obtained a license or permit from the proper governmental agency.