In general, the FAA requires two types of training programs for operators: one for part 121 and part 135 operators electing to transport dangerous goods (will-carry certificate holders), and the other for part 121 and part 135 operators electing not to transport dangerous goods (will-not carry certificate holders).
Will-carry certificate holders must conduct in-depth training for persons directly supervising or performing any of the following job functions involving items for transport on aircraft: acceptance, rejection, handling, storage incidental to transport, packaging of company materials owned or used by the certificate holder (known as COMAT), and loading.
Will-not-carry certificate holders are required to conduct training sufficient to enable the persons directly supervising or performing certain job functions to identify material marked or labeled as dangerous goods, or material that is not marked or labeled as dangerous goods but possesses indicators that it might contain dangerous goods. Some possible indicators of dangerous goods include a hazard label or caution statement on the package with no accompanying shipping documentation, a notation such as "flammable paint," without proper shipping paper declarations or labels or markings.
14 CFR Part 121, Subpart Z, and 135, Subpart K contain information specific to training HazMat Training requirements for domestic operators.
Foreign air carriers are also required to comply with HazMat training requirements for personnel and contractors responsible for acceptance, rejection, handling, storage incidental to transport, packaging of company materials owned or used by the certificate holder (known as COMAT), and loading of cargo.
These requirements are found in 49 CFR Part 175.20.