What are the nine UN hazard classes?

1 explosives, 2 gases, 3 flammable liquids, 4 flammable solids, 5 oxidisers and organic peroxides, 6 toxic and infectious substances, 7 radioactive material, 8 corrosives, and 9 miscellaneous dangerous goods such as lithium batteries and environmentally hazardous substances.

What is the difference between a class and a division?

A class is the broad hazard group; a division is a subdivision within it for a specific risk. For example class 2 (gases) has 2.1 flammable, 2.2 non-flammable non-toxic, and 2.3 toxic. The division appears on the label and in the dangerous goods entry.

Do these classes apply to road, sea and air?

Yes. The same nine UN classes underpin ADR (road), RID (rail), IMDG (sea) and IATA/ICAO (air). The class is consistent across modes, though packing, quantity limits and documentation rules differ between them.

What goes in Class 9?

Class 9 is miscellaneous: substances that pose a transport danger but do not fit classes 1–8. Common examples are lithium-ion batteries, dry ice, asbestos, magnetised material and environmentally hazardous substances such as marine pollutants.

Is this reference a substitute for the dangerous goods regulations?

No. It is an educational summary. For shipping you must consult the current ADR/IMDG/IATA texts and the substance's UN number, packing group and proper shipping name.

UN Hazmat Class Reference

Email me this result

Get this tool's output sent to your inbox, plus one useful tool a week. No spam, unsubscribe any time.

The nine UN dangerous goods classes

Every regulated dangerous good is assigned to one of nine UN classes based on its primary hazard. These classes are shared across the road (ADR), rail (RID), sea (IMDG) and air (IATA/ICAO) regulations, and drive the diamond label, packing group and documentation a shipment needs.

How it works

The class is determined by the substance’s dominant danger — for instance a flammable liquid is Class 3, a corrosive acid is Class 8, a radioactive source is Class 7. Many classes split into divisions that pin down the specific risk: Class 2 gases divide into 2.1 flammable, 2.2 non-flammable non-toxic and 2.3 toxic. The class and division appear together on the hazard diamond and in the entry.

This reference lists every class and its main divisions with the hazard, label colour and typical examples. The search box filters all columns at once.

Tips and example

A drum of petrol is Class 3, flammable liquid, red diamond. A cylinder of chlorine is Class 2.3, toxic gas. Lithium batteries ship under Class 9 with their own special provisions. Substances with more than one hazard get a primary class plus subsidiary risk labels — always work from the substance’s UN number and the current regulations, not the class alone.