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Mixture classification in accordance with the CLP-Regulation

Step by step to success


Correct classification and labelling of mixtures has always been a task in need of diligence and knowledge of the specific rules, which have been for a long time the Directives 67/548/EEC (Dangerous Substance Directive, DSD) and 1999/45/EC (Dangerous Preparation Directive, DPD). These two Directives are now being replaced by the Regulation (EC) No 1272/2008 (CLP-Regulation). Since December 2010 the CLP-Regulation is in force for substances, until the 1st of June 2015 the classification, labelling and packaging of mixtures will also have to comply with the CLP-Regulation.

Below a step-by-step approach is provided to help you with the transition of the classification and labelling of your mixtures to the new CLP standards.

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1 Identify Information

The basic requirement to apply the rules of the CLP-Regulation is to know the composition of your mixture as exact as possible. Compile a list of all ingredients including impurities and additives! Usually hazard properties may get relevant for your mixture if ingredients have concentrations ≥ 0.1 % or ≥ 1 % (depending on the classification). However, severe properties might be relevant at even lower concentrations.

Your basic register of ingredient substances should contain

  • substance identity,
  • concentration in the mixture,
  • hazard categories for classification according to CLP,
  • H-statements and EUH-statements,
  • specific concentration limits and M-factors, where relevant.

The safety data sheet (SDS) is your first source of information. If you formulate a mixture you should have access to the individual safety data sheets (SDSs) for the ingredient substances, which must have been adapted to CLP. If you import a mixture it might be more difficult to obtain the relevant data. However, you might have a SDS compliant with DPD as a starting point which informs you about the relevant ingredients and their properties. Get in contact with your supplier if further information is needed and make sure that your list is comprehensive.

Main data sources are

  • the SDS of your mixture (if available)
  • the SDSs of the individual substances,
  • the database of registered substances,
  • the classification and labelling inventory available at the ECHA website.

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2 Examine Data

Use the basic information outlined above to identify which properties of the individual substances will influence the classification of your mixture. Distinguish between physical hazards, health hazards and environmental hazards. Is the mixture already classified in accordance with the previous legislation (Dangerous Preparations Directive, DPD)? Then you may get a first impression of the CLP classification by using the translation table in Annex VII of the CLP-Regulation.

GHS pictograms on laboratory bottle, Photography: Uwe Völkner, Fotoagentur FOX

NOTE! Due to the differences between DPD and CLP the table in Annex VII very often does not give correct results, use it only as help for orientation! Check BAuA Poster 3 and 4 (in German, but self-explaining) for more detailed information. Conversion can never replace a full assessment. You have to review the classification of your mixture more precisely!

Find out whether you have sufficient, relevant and reliable information available for classification in accordance with the criteria in Annex I of the CLP-Regulation. Do you have data on the mixture itself or do you have to base the classification on the data on the ingredients? Do these data fit well together or are there any obvious contradictions?

Check the existing harmonised classification for your ingredients by searching the ECHA C&L inventory and ensure it is correctly applied to your mixture. The harmonised classification - shown first for each substance and marked in light blue - is mandatory. You also have to find out whether additional classification is necessary for the hazard properties not covered by the harmonised classification. You might use the C&L inventory for a first impression but keep in mind that the self-classifications (marked in yellow) have been collected from manufacturers or importers, so you may frequently discover different classifications for the same substance. For the so called 'joint entries', test data may be available in the ECHA database on registered substances.

Data evaluation is a difficult task, especially if the criteria cannot directly be applied to the available information. This often holds true for mixtures! To a certain extent, you might rely on data on a similar mixture which may be of special interest if you have a broad portfolio of comparable mixtures or extracts from natural products to evaluate. This process is called bridging. In case information is missing or ambiguous, a weight of evidence approach needs to be applied using expert knowledge. Find professional support, if necessary!

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3 Evaluate Data

Assessment of physical hazards usually needs to be based on test data on the mixture itself. In rare cases, e.g. for flammable or oxidising gases, calculation methods may be available to obtain the classification of the mixture from its composition. In other cases testing might be waived, because obviously no meaningful result can be obtained e.g. for flammability of aqueous solutions. Also with some effort data gaps may be closed by considering the transport classifications, but you need to carefully study the data base for transport classification. Please note that some test conditions have changed with the CLP-Regulation, and the according studies have to be repeated in accordance with the new procedures. Make sure that all required test results are available or will be prepared.

For the classification of health hazards data on the mixture itself are valuable but rarely available. Instead the data on the ingredient substances are relevant and shall be used. Since there are several hazards to be considered write thoroughly down what data is available to you. Use the according sections in part 3 of Annex I of the CLP-Regulation to structure your work. If you do not find all the necessary information in the available SDSs, you may search the publicly available databases of ECHA or others to complete your facts. Use expert knowledge to evaluate the available data and their shortcomings because there is no option for additional tests involving animals.

Concerning environmental hazards acute and long-term aquatic toxicity has to be considered. The assessment is usually based on the acute aquatic toxicity of the ingredients and supported with data on degradation and bioaccumulation potential as indication of chronic toxicity. So-called multiplying factors (M-factors) give an increased weight to very toxic substances. If information is missing the database on registered substances might be of help. In other cases don´t hesitate to contact your supplier.

There may also be additional hazards. If a mixture contains ≥ 0.1% of a substance which is hazardous to the ozone layer the mixture itself needs to be classified accordingly (see part 5 in Annex I of the CLP-Regulation). Also a certain content of lead, for instance, or the possibility that toxic gas might be liberated in contact with water needs to be addressed. These hazards are specifically outlined in Annex II to the CLP-Regulation and indicated with EUH-statements. Be careful to identify them!

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4 Decide Classification and Labelling

If you have test data on the mixture itself or similar tested mixtures you can directly compare the data to the criteria given in Annex I to the CLP-Regulation and classify accordingly. This usually holds true for physical hazards. For health and environmental hazards classification is usually based on the content (in %) of the respective ingredients in the mixture. Each hazard chapter in Annex I specifies the concentration limits which trigger the assignment of a specific hazard class or category. For substances with harmonised classification specific concentration limits may have been identified and listed in Annex VI to the CLP-Regulation and will have to be used instead of the generic limits.

Palletised Barrels with Hazard Labelling, Photography: Uwe Völkner, Fotoagentur FOX

With an additive concept all ingredients having the same property are summed up and the result is compared to a certain margin which triggers classification of the mixture. Different potency of the ingredients is usually compensated in these calculations by a weighed approach. Prominent examples are the hazard classes for acute toxicity, irritation and aquatic toxicity. On the contrary, the hazard classes for sensitization, carcinogenicity, mutagenicity and reproductive toxicity are well-known examples for non-additivity. In these cases the ingredients are directly compared to the respective concentration limit independent whether other ingredients also show the same property.

NOTE! Certain decision strategies have been modified with CLP. This may lead to a different classification compared with the previous system although the basic data has not changed. The rules are complex and you probably need to work systematically along the hazard classes as described in Annex I to correctly classify a mixture of interest. For substantial support use in addition the ECHA Guidance on the application of the CLP criteria which was updated in 2013!

After deciding on the classification of your mixture, you should consider the design of the label which needs to include

  • details on supplier
  • product identifier
  • nominal quantity (in the package made available to the general public)
  • hazardous ingredients
  • hazard pictograms
  • the signal word
  • all hazard statements (H-statements and EUH-statements)
  • usually not more than six precautionary statements.

The requirements for the design of the label are very explicit and contain among others standards for the size of the label, the pictogram or the wording for H- and P-statements, which must be respected. Detailed explanation on when to use what is given in the ECHA Guidance on labelling and packaging.

Finally you need to adapt the SDS according to the new CLP-compliant classification and labelling of your mixture. Do you identify a substantial change? You should outline that to your customers! Further information on how to design an up-to-date SDS in full compliance with REACH and CLP is given in the ECHA Guidance on the compilation of safety data sheets.

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5 Review

Since the information background has been improved with REACH new data is derived and made available all the time. This new and additional information can have a direct impact on the (harmonised) classification of a substance and might affect your mixtures containing the substance. But also changes in the legal text are possible, especially adaptation to the technical progress concerning classification criteria. Additionally, your supplier might choose to modify the mixture and change its composition.

For all these reasons there is a need to review regularly whether information has become available which influences your classification and labelling. Make a scheme to plan your work in advance and stick to it. Keep your information updated and establish a concept to react on new impacts regarding classification and labelling as soon as possible.