Flammable materials can be gaseous, liquid, or solid or combinations of these. For the purpose of this general classification, explosive materials may be considered only those which are inherently unstable chemically with respect to themselves so that they can decompose or react under the influence of heat, light, shock, spark ignition, high-frequency wave motion, or general aging and do this with such a rapid evolution of energy that explosive forces result. Common compounds of this classification are organic nitrates, perchlorates, peroxides, fulminates, oxides, hydrides, and others. Materials in this classification can consist of gases, liquids, and solids. The degree of toxicity can range from slight to deadly.
Corrosive materials range from mildly active to materials capable of causing deep chemical burns.
Corrosive materials include hydrochloric acid, nitric acid, sulfuric acid, carbolic acid, chlorine, phosphorous, lime, caustin, and others. Materials in this classification are all of those which emit alpha, beta, or gamma radiation. Calcium carbide reacts with water to form lime and acetylene, an explosive gas. All materials reacting with commonly encountered substances to form dangerous materials are considered to be in this class. The sources of these materials are usually hospitals and clinical and research laboratories.