BPA (bisphenol A) is a chemical traditionally used to make hard, clear plastics—including food containers, reusable water bottles and some baby bottles—and the resins lining some food cans. It leaches into food, particularly acidic items, such as tomatoes, or when containers are scratched or heated. Similar in structure to estrogen, BPA is considered a so-called endocrine disruptor. Based on animal and (limited) human studies, scientists are concerned that BPA may be linked with prostate and breast cancer, infertility, heart disease and diabetes.