Classification

Dangerous goods are divided into nine classes according to the type of hazard they present. Articles and substances are assigned to each class based on specific criteria. DGR Section 3 - Classification describes in detail how to classify dangerous goods into one or more of the nine UN hazard classes.

Each class is represented by a single-digit number, such as Class 1. Some classes are further divided into divisions due to hazard variation within the class. Divisions are represented by a two-digit number. The first digit indicates the class, and the second digit identifies the variation within that class. For example, oxidizers, which are Class 5, Division 1 substances, are in Division 5.1.

The nine hazard classes are:

• Class 1 - Explosives
• Class 2 - Gases
• Class 3 - Flammable liquids
• Class 4 - Flammable solids; substances liable to spontaneous combustion; substances which, in contact with water, emit flammable gases
• Class 5 - Oxidizing substances and organic peroxides
• Class 6 - Toxic and infectious substances
• Class 7 - Radioactive material
• Class 8 - Corrosives
• Class 9 - Miscellaneous dangerous goods

Please note that the class numbers are for convenience only; they DO NOT indicate a relative degree of danger.

Some dangerous goods meet the classification criteria for more than one class or division. When an article or substance has multiple hazards, it is assigned a primary and subsidiary class.

In addition to the UN classification system, operators use three-letter Cargo-IMP (Interline Message Procedures) Codes to facilitate the recognition of dangerous goods. A code is assigned to each class/division and is used on flight documents, such as cargo manifests and Special Load - Notification to Captain (NOTOC).

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