The Federal Insecticide, Fungicide, and Rodenticide Act (FIFRA) was amended in 1988 to accelerate the reregistration of products with active ingredients 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 (hereafter referred to as 'the Agency') to determine whether a pesticide containing such an active ingredient is eligible for reregistration. Thus, reregistration involves a thorough review of the scientific database underlying a pesticide's registration. The purpose of the Agency's review is to reassess the potential hazards arising from the currently registered uses of the pesticide, to determine the need for additional data on health and environmental effects; and the determine whether the pesticide meets the 'no unreasonable effects' criterion of FIFRA. On August 3, 1996, the Food Quality Protection Act of 1996 (FQPA) was signed into law. This Act amends FIFRA to require tolerance reassessment during reregistration. FQPA also amends the Federal Food, Drug, and Cosmetic Act (FFDCA), to require a safety finding in tolerance reassessment based on factors including an assessment of cumulative effects of chemicals with a common mechanism of toxicity. Profenofos belongs to a group of pesticides called organophospates which share a common mechanism of toxicity. They all affect the nervous system by inhibiting cholinesterase. Therefore, tolerance reassessment requires that the Agency consider, among other thing, the cumulative effects of exposures to all organophosphates. This document presents the Agency's revised human health and ecological risk assessments; its progress toward tolerance reassessment; and the interim reregistration eligibility decision for profenofos. It is intended to be only the first phase in the reregistration process for profenofos. The Agency will
eventually proceed with its assessment of the cumulative risk of the OP pesticides.