Abstract
Bisphenol A (BPA), a synthetic chemical used in the production of plastics since the 1950s and a known endocrine disruptor, is a ubiquitous component of the material environment and human body. New research on very-low-dose exposure to BPA suggests an association with adverse health effects, including breast and prostate cancer, obesity, neurobehavioral problems, and reproductive abnormalities. These findings challenge the long-standing scientific and legal presumption of BPA's safety. The history of how BPA's safety was defined and defended provides critical insight into the questions now facing lawmakers and regulators: is BPA safe, and if not, what steps must be taken to protect the public's health? Answers to both questions involve reforms in chemical policy, with implications beyond BPA.