46 CFR § 153.1118
Prewash of Categories B and C cargo tanks not meeting stripping standards: Categories B and C
April 15, 2021
(a) Unless §153.1114 allows the prewash to be omitted, a cargo tank from which a Category B NLS is unloaded must be prewashed using the procedures in §153.1120(b) if the tank—
(1) Operates under the interim standard in §153.481(b); or
(2) Has a waiver issued under §153.483.
(b) Unless §153.1114 allows the prewash to be omitted, a cargo tank from which a Category C NLS is unloaded must be prewashed using the procedures in §153.1120(b) if the tank has a waiver issued under §153.483.