Evaluate information against classification criteria

Evaluate information against classification criteria

After gathering all the information and assessing its validity, it is time for you to compare the data to the criteria for classification and decide on the classification of the mixture. The criteria are given for each hazard class or differentiation in Parts 2 to 5 of Annex I to the CLP Regulation.

In the evaluation of the gathered data, it is recommended that you follow the logic of the step-wise approach in Figure 1.6.1-a in the Guidance on the application of CLP criteria. You will need to follow the decision sequence separately for each hazard class. In general, the following situations need to be considered:

  • If for a certain hazard class data are available on the individual substances, the decision on the classification of the mixture can be based either on the concentration of the substances in the mixture, taking into account the SCLs and M-factors, or on calculations using specific formulae. The methods are specified separately for each hazard class in Annex I to CLP (see Section of the Guidance document).
  • If test data on the mixture itself are available, they can mostly be directly compared to the classification criteria for substances in Annex I to CLP and the mixture classified accordingly (see Section of the Guidance on the application of CLP criteria).
  • Even if you do not have data on the mixture itself, you may have it on similar tested mixtures. If the mixture and the similar tested mixtures fulfil the conditions explained in Chapter the Guidance on the application of CLP criteria, bridging principles may be used to classify the mixture. The bridging principles mainly apply to either very simple mixtures or very straightforward compositional changes in an already classified mixture. The Guidance provides simple examples concerning bridging principles.

If you decide that the information on the mixture or the substances in the mixture is not sufficient for classification purposes, contact your suppliers.  

The process of evaluating hazard information is outlined in Chapter 2 (Articles 9 to 12) of the CLP Regulation. We recommend using the specific sections in Annex I to CLP to structure your work.


For which hazards must I use information on individual substances?

Carcinogenicity, mutagenicity, reproductive toxicity as well as bioaccumulation and biodegradation properties within the evaluation for ‘hazardous to the aquatic environment' must always be assessed based on the individual substances in the mixture.

Additionally, in practice the classification of a mixture for skin and respiratory sensitisation is usually based on the individual substances, as a mixture must be classified as a respiratory or skin sensitiser when at least one component has been classified as such and it is present at or above the appropriate generic concentration limits.


What about testing?

With regard to physical hazards, test data on the mixture itself needs to be generated where adequate and reliable information e.g. from reference literature or databases is not already available.

CLP does not require new testing for the purpose of classification for health or environmental hazards. To avoid unnecessary testing on animals, such data should normally not be generated for mixtures. Instead, all available information on the individual substances in the mixture should be used to decide on a classification. Some methods using cell cultures or tissues may be applicable, e.g. for testing the corrosive potential of mixtures with extreme pH which have a low buffering capacity.


Mixtures already classified in accordance with Directive 1999/45/EC (Dangerous Preparations Directive)

Anyone who has previously applied the rules of the Dangerous Preparations Directive (DPD) should take note that the application of CLP also includes several changes in the calculation formulae and the classification criteria, and thus re-calculation and reclassification are often needed. For properties such as acute toxicity, irritation, sensitisation and reproductive toxicity, the resulting classification is often different from the previous system, even though the underlying data have not changed. When reclassifying, make sure that you consider all the relevant chapters in Annex I to CLP, as is further explained in the Guidance on the application of CLP criteria.

If your mixture has already been classified in accordance with DPD (prior to 1 June 2015) and despite all efforts you do not have access to any data on the mixture or the substances in the mixture, it may be possible to use the translation table 1.1 in Annex VII to CLP to convert certain hazard classes from the previous DPD classification to classification in accordance with CLP. It is, however, important to note that when data for the substance or mixture is available for a hazard class, the substance or mixture must be classified in accordance with CLP criteria and the Annex VII tables must not be used. New information can affect a classification, and thus the DPD classification may no longer be accurate and the use of the translation table will not give an acceptable result.

The translation table should only be used to help provide direction for a possible classification of the mixture. The possibilities and limitations of using Annex VII to CLP are explained in chapter 1.7 of the Guidance on the application of CLP criteria.

Evaluate information against classification criteria