Any substance or article, including a device, which is designed to function by explosion, or which, by chemical reaction within itself, is able to function in a similar manner even if not designed to function by explosion. Included are substances which have a mass explosion hazard (Division 1.1); a projection hazard, but not a mass explosion hazard (Division 1.2); and a fire hazard and either a minor blast hazard or a minor projection hazard or both, but not a mass explosion hazard (Division 1.3).

Note 1: (**)Appropriate division number and compatibility group are to be placed in the label, e.g., 1.1 D.

Note 2: Labels used to identify a subsidiary risk must display the symbol only; any number(s) must be obliterated.

Also see:
    What are the Federal Regulations for Hazardous Materials Labeling?