Learning from experience: A retrospective analysis of read-across strategies for surfactants under REACH

Read-across is a widely used adaptation to address information requirements under REACH. However, registrants submitting for the 2010 and 2013 deadline have often failed to satisfy regulatory requirements from ECHA's point of view. Due to their complex composition and unique physicochemical properties, surfactants are posing major challenges in this respect. With the aim to improve future submissions and prevent unnecessary animal testing, read-across-related discussions of 72 ECHA Final Decisions on Compliance Checks and Testing Proposal Evaluations of 24 major surfactant groups were analysed in-depth, and causes for acceptance or rejection were identified. Key drivers of regulatory acceptance/rejection were presence or absence of composition information, considerations on structural similarity as well as availability and nature of bridging studies. Several elements were identified that may be easily improved in future REACH dossiers without the need for additional animal testing. Other cases revealed uncertainty of expectations by ECHA, highlighting the need for improved communication during the dossier preparation. Notably, no example for acceptance of read-across based on non-animal New Approach Methodologies (NAMs) was identified in this analysis. Owing to the benefits that non-animal NAMs may present as supporting information, all stakeholders are encouraged to contribute to an increase of regulatory acceptance.