Definition: Commodities, which possess potentially hazardous characteristics. These are as the laid out by IATA in the Dangerous Goods Regulations.
Class 1: Explosives
Class 2: Gases
Class 3: Flammable Liquids
Class 4: Flammable Solids
Class 5: Oxidizers and Organic Peroxides
Class 6: Toxic & Infectious Substances
Class 7: Radioactive Material
Class 8: Corrosives
Class 9: Miscellaneous e.g. Magnets – a danger to airplane equipment
