As part of a multi-year, $816 million initiative to assess the risks posed by thousands of commonly used chemicals and compounds, Canada became the first country in the world to declare that bisphenol A (BPA) was toxic and justified regulation in April 2008. The process set up to conduct this risk assessment differed from the previous Canadian experience with the regulation of hazardous substances in that it was more formal, systematic and more pluralistic with much greater participation from interest groups. This case study explores the politics and process behind this decision and argues that the government’s decision went beyond what scientific evidence could justify. The decision resulted from long-term institutional factors such as the incentive structure of Canadian federalism and values embedded in legislation as well as short-term factors such as media coverage, public opinion and interest group pressure.