46 CFR § 148.280
Magnesia, unslaked (lightburned magnesia, calcined magnesite, caustic calcined magnesite)
April 15, 2021
(a) This part does not apply to the transport of natural magnesite, magnesium carbonate, or magnesia clinkers.
(b) When transported by barge, unslaked magnesia must be carried in an unmanned, all-steel, double-hulled barge equipped with weathertight hatches or covers. The barge may not carry any other cargo while unslaked magnesia is on board.
(c) The shipping paper requirements in §148.60 of this part and the dangerous cargo manifest requirements in §148.70 of this part do not apply to unslaked magnesia transported under the requirements of paragraph (b) of this section.