The European Union (EU) has greatly expanded its environmental legislation over the past two decades. This article analyzes the recent development of the REACH (Registration, Evaluation and Authorization of Chemicals) regulation. It uses a process-tracing technique to explore the question of how REACH was created despite signifıcant resistance from influential and well-organized industry interests and misgivings from leading European politicians and policy-makers. Examining developing coalition politics within the EU, it is argued that a relatively small coalition of green actors from EU organizations, member states, and environmental and public health advocacy groups succeeded in ensuring the development and adoption of REACH largely because the coalition included influential members from all major EU policy-making centers (the European Commission, the Council of Ministers, and the European Parliament). In addition, it is argued that the implementation of REACH can have important ramiıcations for international chemical politics and policy-making outside the EU.