46 CFR § 30.10-69
Tank vessel—TB/ALL
April 15, 2021
The term tank vessel means a vessel that is constructed or adapted to carry, or that carries, oil or hazardous material in bulk as cargo or cargo residue, and that—
(a) Is a vessel of the United States;
(b) Operates on the navigable waters of the United States; or
(c) Transfers oil or hazardous material in a port or place subject to the jurisdiction of the United States.
[CGD 79-116, 62 FR 25135, May 8, 1997]