Classification of dangerous goods

Different substances and objects may have the same main danger and therefore belong to the same danger class. Nevertheless, they may have such different properties that they should be treated differently. A hazardous substance may have additional hazards which mean that several hazard classes are specified. The product may also have been assigned a packaging group that identifies the degree of danger that the substance has, based in part on the degree of strength of the substance.

It is the total information with UN number, hazard class and packaging group, as well as any classification code that constitutes the so-called classification for the item.

Do you need more information about classification of dangerous goods?

Packaging and packaging groups

Proper transport of dangerous goods requires that the packaging is solid and can withstand the stresses both during normal transport and in the event of accidents. All packaging must meet special requirements for strength and durability. The regulations describe how the packaging for dangerous goods must be designed, tested and approved. The approval code must be printed on the packaging itself. There are different requirements for the packaging based on the properties of the dangerous goods, including provisions on the permitted amount in the packaging, whether there are requirements for double packaging, and whether there is a possibility of co-packaging or not.

Most hazard classes are assigned to a packaging group (the exceptions are class 1, 2, 5.2, 6.2, and 7, as well as self-reactive substances in class 4.1.)

The packaging group is also an important key to deciding whether the dangerous goods come under exceptions and exemptions from the provisions of ADRDangerous Goods by Road (ADR)
Goods that can do harm to people or the environment

There are three packaging groups

  • packing group I: very dangerous substance

  • packing group II: medium dangerous substance

  • packing group III: less dangerous substance

Labels and other markings

The marking of the package is very important for your goods to be treated correctly, and for everyone involved in the transport to know from the marking how they should behave. Labels must not be hidden or covered. There are separate danger labels for the various danger classes, see the picture below.

The package must be affixed

  • the substance's UN number

  • danger labels (a substance may have several dangerous properties, and must then be marked with several danger labels)

  • other markings and information (applies to some types of dangerous goods)

Air and sea transport require that the product name/proper shipping name is stated on the package. Air transport also requires that you apply weight/quantity to the package. You, as the sender, must mark the goods correctly in relation to whether it is a combined transport that involves both road and plane/possibly boat.

These are examples of hazard labels that show which hazard classes the dangerous goods belong to (what kind of hazard the substance has), see the illustration above.

The provisions on marking and danger labels on packages can be found in ADR part 5 «preparing for shipment».

Other markings on the package

Labels and other markings must not be covered or hidden. If overpacking is used, markings on the packages must be clearly visible through the packaging. If this is not the case, the packaging itself must be marked in the same way as the packages inside.


For details on packaging, see ADR Part 5, Chapter 5.1.2.


Jon Marsteintrædet

Jon Marsteintrædet

HSEQ Advisor