P27-23 Use of grouping and read-across approaches in the context of the EU Regulation on the classification, labelling and packaging of substances and mixtures (CLP)

Read-across is a well-established scientific approach to extrapolate properties from data-rich to data-poor chemicals to determine their hazardous properties and so reducing the need for new animal studies. In the context of the EU Regulation on the Registration, Evaluation, Authorisation and Restriction of Chemicals (REACH), it is the most widely used option of alternatives to fulfil standard information requirements. ECHA finds that adaptations for standard information requirements under REACH based on grouping and read-across are often not compliant and therefore has developed guidance and advice aimed at improving their use [1] . Grouping and read-across are also being used for determining the hazard of substances for the classification of chemicals. The EU Regulation on the classification, labelling and packaging of substances and mixtures (CLP Regulation) is a cornerstone of chemical management in Europe. An assessment of the available data relevant to the substance or mixture using the CLP criteria leads to identification of hazards and results in appropriate labelling and risk management measures, e.g. for handling and storage. Companies should self-classify their substances according to the criteria of the CLP Regulation. In addition, the classification of substances may be harmonised in legally binding agreements on the classification of substances at EU-level (entered into Annex VI of CLP). Certain hazard classes trigger specific risk management measures. For example, the supply of substances harmonised classified as carcinogenic, mutagenic or reprotoxic (CMR) category 1A/1B to the general public is restricted. There are already ‘group entries’ in Annex VI to CLP. In the recent CLP revision (December 2024), more emphasis was placed on the use of groups for harmonised classiications. Considering groups of substances is more efficient, as greater numbers of substances can be assessed for classiication at one time, thereby resulting in a more substantial increase in the protection of human health and the environment. Twenty-six percent of the Risk Assessment Committee (RAC) opinions on harmonised classification between 2017 and 2021 included read-across approaches. Examples of types of read-across comprise conjugated base and acid, common hydrolysis products and substances sharing the same toxic metabolite. Assessing grouping and read-across under the criteria of CLP (versus, for example, compliance with REACH information requirements) introduces particular considerations. The poster will show these considerations for using and assessing grouping and read-across in the context of CLP. They are at the basis of the Practical Guide on ‘Grouping and read-across under CLP’ which ECHA is developing. [1] for example ECHA Read-Across Assessment Framework (2017), Advice on using read-across for UVCB substances (2022), Recommendations to registrants on ECHA website