Abstract: A non-detonable explosive scent source for use as a tool in training dogs to detect explosive is disclosed. The tool utilizes actual explosive materials as the scent source, and not diluted or synthetic explosive materials. The explosive is contained in a carrier made from a non-volatile material such as metal, ceramic or the like. The explosive is contained in sub-critical dimension receiver spaces formed within the carrier and exposed to atmosphere. The receiver spaces have at least one dimensional parameter less than the “critical thickness” of the explosive material. “Critical thickness” relates to a property of explosive materials that requires every dimension of the explosive material in a charge must exceed the critical thickness property of the explosive used or the charge will not detonate. When any dimension of a charge's explosive material is smaller than the explosive's critical thickness, the charge in effect ceases to be an explosive charge.