Explosive that presents a minor explosive hazard, and explosive effects
are confined to the package; no projection of fragments of appreciable
size or range is to be expected. An external fire must not cause virtually
an instantaneous explosion of almost the entire contents of the package;
previously designated by the U.S. Department of Transportation as a Class
C explosive and defined as containing Class A or Class B explosives, or
both, as components but in restricted quantities.
Dictionary of Mining, Mineral, and Related Terms