The Federal Insecticide, Fungicide, and Rodenticide Act (FIFRA) were amended in 1988 to accelerate the reregistration of products containing active ingredients originally registered prior to November 1, 1984. The amended Act calls for the development and submission of data to support the reregistration of an active ingredient, as well as a review of all submitted data by the U.S. Environmental Protection Agency (EPA or 'the Agency'). Reregistration involves a thorough review of the scientific database supporting a pesticide's registration. The purpose of the Agency's review is to reassess the potential hazards and benefits arising from the currently registered uses of the pesticide; to determine if there is a need for additional data on benefits, health and environmental effects; and to determine whether the pesticide meets the 'no unreasonable adverse effects' criteria of FIFRA. The document presents the Agency's revised human health and ecological risk assessments; its progress toward tolerance reassessment; and the interim decision on the reregistration eligibility of atrazine. It is intended to be only the first phase in the deregistration process for atrazine. The Agency will eventually precede with its assessment of the cumulative risk of the triazine pesticides and issue a final reregistration eligibility decision for atrazine.