The classifications of dangerous goods are those defined by the United Nations Committee of Experts on the Transport of Dangerous Goods and subsidiary bodies (ST/SG/AC.10/1/Rev.5). There are nine classes of dangerous goods: 1. explosives; 2. gases; 3. flammable liquids; 4. flammable solids, substances liable to spontaneous combustion, substances which, on contact with water emit flammable gases; 5. oxidizing substances, organic peroxides; 6. poisonous (toxic) and infectious substances; 7. radioactive material; 8. corrosives; and, 9. miscellaneous dangerous substances.