49 CFR 176.57
Supervision of handling and stowage.
(a)Hazardous materials may be handled or stowed on board a vessel only under the direction and observation of a responsible person assigned this duty.#
(b)For a vessel engaged in coastwise voyages, or on rivers, bays, sounds or lakes, including the Great Lakes when the voyage is not foreign-going, the responsible person may be an employee of the carrier and assigned this duty by the carrier, or a licensed officer attached to the vessel and assigned by the master of the vessel.#
(c)For a domestic vessel engaged in a foreign-going or intercoastal voyage, the responsible person must be an officer possessing an unexpired license issued by the USCG and assigned this duty by the master of the vessel.#
(d)For a foreign vessel, the responsible person must be an officer of the vessel assigned this duty by the master of the vessel.#