Review the classification
Remember that the classification of a mixture may need to be reviewed for many reasons.
The harmonised classification and labelling of substances in Annex VI to CLP may be changed when new information becomes available and has been reviewed. This can affect the classification of your mixture. Such changes to harmonised classification must be adopted following a transitional period of normally eighteen months following their publication in the official journal of the European Union.
In addition, while examining the available data related to classification, you may have identified certain aspects which are still under discussion. For example, a proposal for harmonised classification and labelling of a substance has been submitted, but the harmonised classification and labelling of the substance is not yet finalised and is not yet included in Part 3 of Annex VI to CLP or a substance has a number of differing entries in the C&L Inventory and a discussion to reach an agreement on the classification is on-going or foreseeable. This is an indication that the classification of the substance may soon be modified. In such a case, you should keep yourself updated by regularly checking the published amendments of the CLP Regulation (Adaptations to Technical Progress, ATPs), the relevant entries in the C&L Inventory and the relevant opinions of technical and scientific committees (especially the opinions of ECHA's Risk Assessment Committee).
When your supplier has changed the classification of a substance or mixture you use or import, you must always re-evaluate the classification of the mixture you formulate or import.
When a change is introduced in a mixture either by a formulator in the EU/EEA or by the non-EU/EEA manufacturer of an imported mixture, a new evaluation must be carried out. A change in classification can result from:
a. A change in the concentration of one or more of the hazardous constituents (see Table 1.2 in Annex I to CLP).
b. A change in the composition involving the substitution or addition of one or more constituents.
c. Significant variation from batch to batch may require a new evaluation of classification. Small variations do not necessarily affect classification. This is explained in Chapter 18.104.22.168.2 of the Guidance on the application of CLP criteria (Bridging principles – Batching).
The registration process under the REACH Regulation requires the extensive collection and generation of information on substances. This has resulted in a significant increase in available information and therefore often leads to a requirement to review the classification and labelling of mixtures containing such substances.
A change in the classification of a mixture may also result from changes in legislation, especially changes in the classification criteria as a result of an adaptation to technical progress (ATP) to CLP. Such changes to CLP criteria must be adopted following a transitional period of normally eighteen months following its publication as an official journal of the European Union.
As you have to adapt the classification of your mixture in accordance with the outcome of the new evaluation and also update the label and the safety data sheet as soon as possible, make sure that you stay up-to-date with both emerging new information and legislative changes. You should also establish a plan to react to new developments regarding classification and labelling without undue delay.