What are the nine classes of Dangerous Goods?
Dangerous Goods are grouped into nine UN transport classes according to the main hazard they present. Some classes have divisions that describe the hazard more precisely. The class number does not indicate how dangerous a substance is. UK Department for Transport, UNECE
Class 1 — Explosives includes substances and articles that can explode, such as fireworks. Divisions 1.1 to 1.6 distinguish different types of explosive hazard.
Class 2 — Gases covers gases under pressure. Division 2.1 is for flammable gases, such as propane, acetylene and hydrogen, 2.2 for non-flammable and non-toxic gases, including oxygen, nitrogen, argon and carbon dioxide, and 2.3 for toxic gases, such as chlorine or carbon monoxide.
Class 3 — Flammable liquids includes liquids that can ignite readily, such as petrol and some solvents.
Class 4 — Flammable solids has three divisions: 4.1 for flammable solids, such as matches or sulphur, 4.2 for substances liable to spontaneous combustion, the best example being phosphorus and 4.3 for substances that release flammable gas when they contact water, such as calcium carbide and many metal powders..
Class 5 — Oxidising substances and organic peroxides includes substances that can intensify a fire by supporting combustion (division 5.1) and organic peroxides that may be unstable or burn rapidly (division 5.2).
Class 6 — Toxic and infectious substances covers substances that can cause poisoning (division 6.1) and materials containing infectious agents (division 6.2).
Class 7 — Radioactive material covers material that emits ionising radiation.
Class 8 — Corrosive substances includes substances that can damage living tissue or other materials, such as caustic soda, hydrochloric acid or sulphuric acid.
Class 9 — Miscellaneous dangerous substances and articles covers transport hazards that do not fit into the other classes, including lithium batteries, asbestos, heated products and environmentally hazardous substances.
Correct classification is the starting point for determining the packaging, labels, documentation and transport conditions that apply to a shipment. UK Department for Transport