This interrupted case study, developed for an honors seminar and a nonmajors chemistry course, is based on data taken from a series of published research articles. The case explores the unintended side effects of chemicals introduced into the environment, specifically organic compounds that can act as environmental estrogens. Students examine the data on the effects of the herbicide atrazine on the environment, then discuss the scientific, political, and economic issues that underlie the controversy surrounding its sale in the United States. (Contains 7 figures and 2 resources.)