((a)) ** Coverage** No person may—

((1)) import into the customs territory of the United States from any place outside thereof (but within the United States), or import into the United States from any place outside thereof, any controlled substance or list I chemical, or

((2)) export from the United States any controlled substance or list I chemical,

((b)) ** Exemptions**

((1)) The following persons shall not be required to register under the provisions of this section and may lawfully possess a controlled substance or list I chemical:

((A)) An agent or an employee of any importer or exporter registered under if such agent or employee is acting in the usual course of his business or employment.

((B)) A common or contract carrier or warehouseman, or an employee thereof, whose possession of any controlled substance or list I chemical is in the usual course of his business or employment.

((C)) An ultimate user who possesses such substance for a purpose specified in section 802(25)  of this title and in conformity with an exemption granted under .

((2)) The Attorney General may, by regulation, waive the requirement for registration of certain importers and exporters if he finds it consistent with the public health and safety; and may authorize any such importer or exporter to possess controlled substances or list I chemicals for purposes of importation and exportation.