The Environmental Protection Agency (EPA) has the authority to regulate inert ingredients present in pesticide products registered for use in the United States. Until recently, most of EPA's regulatory activities focused on the pesticide active ingredient, rather than the other components of the pesticide formulation known as inert ingredients. Although EPA has considered inert-specific data when reviewing some of the inert ingredients currently accepted for use in pesticides applied to food, it wasn't until the publication of EPA's Inert Strategy that a comprehensive policy regarding the information needed to determine the acceptability of a pesticide product inert ingredient was established. The implementation of this policy has led to changes in the types of substances proposed for use as inert ingredients as well as advancements in the methods for reviewing new inert ingredients. Emphasis on the long-term health and environmental effects of inert ingredients now requires pesticide registrants and others to consider these effects when developing new formulations. In order to encourage the use of less toxic inert ingredients, EPA has streamlined its review process, resulting in quicker decisions and more timely market introductions.