The battle over the chemical bisphenol A, or BPA, widely used in polycarbonate plastics and epoxy resins in food cans, holds lessons for the assessment of a broad range of chemicals whose possible impact on human health remains elusive, speakers said at a recent AAAS panel discussion.

Some studies in animals suggest that BPA can disrupt the endocrine system, with potentially harmful effects on growth and development. Canada plans to ban plastic baby bottles made with BPA, and some groups in the United States and Europe are calling for the same action.