46 C.F.R. § 97.12-1

(a) A bulk solid cargo—

(1) Consists of particles, granules, or larger pieces of material generally uniform in composition;

(2) Is not grain; and

(3) Is loaded directly into a vessel's cargo space with no intermediate form of containment.

(b) Additional requirements for bulk solid materials needing special handling are contained in Part 148 of this chapter.