Guidance on Grouping of Chemicals, Third Edition

The OECD Guidance on Grouping of Chemicals describes approaches to consider closely related chemicals as a group rather than individually and apply read-across approaches for filling data gaps. The first edition was published in 2007 and the second edition was published in 2014. This third edition incorporates New Approach Methodologies (NAMs) such as adverse outcome pathways (AOPs), omics technologies, high-throughput screening and (Q)SAR models for developing groups and substantiating similarity. The guidance outlines how to establish the scientific basis for read-across approaches to fill data gaps, integrates insights gained from the OECD IATA Case Study Project and describes new methods to quantify read-across performance and uncertainties. This edition expands coverage of mechanistic-based approaches and includes guidance for metals and nanomaterials grouping. The document provides critical guidance for assessing the hazards of chemicals using approaches that gain efficiencies and reduce reliance on animal testing.