Classification of substances and mixtures

A core principle of the Classification, Labelling and Packaging (CLP) Regulation is the 'self-classification' of a substance or mixture by the manufacturer, importer or downstream user.

This involves identifying the hazards of the substance or mixture and comparing the hazard information with the criteria laid down in CLP. The classification is based on the hazardous properties of a substance or mixture and not on the likelihood of exposure and risk considerations.

Self-classification aims to determine whether a chemical substance or mixture has physical, health and/or environmental hazards and to properly communicate these hazards with appropriate labelling in the supply chain when the product is placed on the market, regardless of the volume of the substance or mixture produced.


Under CLP, a substance must be self-classified when it has no harmonised classification in Annex VI to CLP and it presents hazardous properties. For a substance that already has a harmonised classification (an entry in Annex VI to CLP), the harmonised hazard classification is legally binding for the hazard classes and differentiations covered in the entry. The hazard classes and differentiations not covered in the entry must be evaluated and self-classified, as appropriate.

Some exceptions to a harmonised classification may be applicable if justified by e.g. a different physical state or form of the substance put on the market or a note associated with the Annex VI entry. In addition, a classification indicated in Annex VI as a minimum classification, should be evaluated based on available information and if there is data that leads to the classification of the substance in a more severe category than the minimum, the more severe category must be used.

Other uncertainties related to the 'translation' of hazards from the Dangerous Substances Directive (DSD) to CLP must be carefully evaluated. In any case, when a substance is self-classified (in addition to its harmonised classification in Annex VI to CLP) the decisions must be justified and agreed, if appropriate, with other manufactuers, importers or downstream users.

For a substance with no current Annex VI entry (i.e. the substance has no harmonised classification for any hazard class), all relevant hazard classes must be assessed by the manufacturer or importer and the self-classification must be applied to all hazard classes for which the classification criteria are fulfilled.

Mixtures must always be self-classified before being placed on the market, as they are not subject to harmonised classification and labelling (CLH).

To derive a self-classification, the classifier must gather all the available information and evaluate its adequacy and reliability. The information then needs to be evaluated against the classification criteria and the corresponding classification has to be decided.

Classifying mixtures follows a similar process. They can be classified based on data on the mixture itself, data on similar tested mixtures, or data on the individual components in the mixture.

Manufacturers, importers and downstream users need to follow new scientific or technical developments and decide whether a re-evaluation of the self-classification of the substance or mixture they place on the market should be conducted.