46 C.F.R. § 4.03-70
Tank vessel
Tank vessel means a vessel that is constructed or adapted to carry, or that carries, oil, hazardous substances, marine pollutants, or noxious liquid substances, in bulk as cargo or cargo residue.
Tank vessel means a vessel that is constructed or adapted to carry, or that carries, oil, hazardous substances, marine pollutants, or noxious liquid substances, in bulk as cargo or cargo residue.