(a) Except as provided by this section, no OSV may carry flammable or combustible liquid cargoes in bulk without the approval of the Commandant (CG-OES).

(b) An OSV may carry the following in integral tanks:

(1) Grade-D combustible liquids listed by § 30.25-1 of this chapter, in quantities not to exceed 20 percent of the vessel's deadweight, except that the vessel may carry drilling fluids and excess fuel oil, Grade-E as well as Grade-D, without limit.

(2) Grade-E combustible liquids listed by § 30.25-1 of this chapter, in quantities not to exceed 20 percent of the vessel's deadweight, except that the vessel may carry drilling fluids and excess fuel oil, Grade-D as well as Grade-E, without limit.

(3) Other flammable or combustible liquids as authorized in § 125.125 of this part.

(c) An OSV may carry the following in fixed independent tanks on deck: Grade-B and lower-grade flammable and combustible liquids listed by § 30.25-1 of this chapter, in quantities not to exceed 20 percent of the vessel's deadweight.

(d) An OSV may carry hazardous materials in portable tanks, in compliance with part 64 and subpart 98.30 of this chapter. A portable tank may be filled or discharged aboard the vessel if authorized by an endorsement on the vessel's Certificate of Inspection.

(e) On an OSV of at least 6,000 GT ITC (500 GRT if GT ITC is not assigned), tanks authorized for carriage of oil as defined by 33 CFR 157.03, including drilling fluids containing oil as defined by 33 CFR 157.03, must comply with double hull requirements stated in 33 CFR 157.10d.

Note to § 125.110(e): Additional limitations on the carriage of flammable or combustible liquid cargoes are found in § 127.650 of this part.