[Regulatory Update] EU's "One Substance, One Assessment" (OSOA) Laws Enter into Force on 1 January 2026: A Common Data Platform on Chemicals to Be Established

On 5 January 2026, the European Commission announced that the EU's "one substance, one assessment" (OSOA) laws entered into force on 1 January 2026. The Commission says the framework is intended to make chemical assessments more consistent, transparent and efficient across EU legislation, covering products such as toys, food, pesticides and biocides. The package consists of three legislative acts: a Regulation establishing a common data platform on chemicals and a monitoring and outlook framework, a Regulation re-attributing technical tasks and improving cooperation among EU agencies, and a Directive on the re-attribution of technical tasks to the European Chemicals Agency (ECHA). The common data platform, the core of the package, was described at the time of the January 2026 announcement as due to be operational within three years; it is to bring together chemical data collected under various EU laws so that public authorities can re-use it more easily. The Commission also cites a clearer division of tasks among EU chemicals agencies to reduce duplication, and a monitoring and outlook framework to detect emerging chemical risks earlier.