On June 7, 2000, the U.S. Environmental Protection Agency (EPA) reached an agreement with the basic manufacturers of chlorpyrifos to reduce potential risks from exposure to residues from pesticide products containing chlorpyrifos. More commonly known by the trade names Dursban and Lorsban, chlorpyrifos is the most commonly used pesticide in and around homes in the United States. Prior to this agreement, chlorpyrifos was the active ingredient in more than 800 chlorpyrifos pesticide products registered by EPA for a variety of uses, including termite control, home lawn and garden use, pet collars, mosquito and fire ant control, indoor crack and crevice treatment, and as an insecticide on more than 40 agricultural crops. In June 2000, EPA estimated that 21 to 24 million pounds of chlorpyrifos are applied on average per year, with one-half of this amount applied in nonagricultural settings such as in and around homes, schools, office buildings, and parks.

Prior to negotiating the Memorandum of Agreement Between EPA and Signatory Registrants Regarding the Registration of Pesticide Products Containing Chlorpyrifos (Chlorpyrifos Agreement or Agreement), EPA reviewed several hundred studies, conducted several assessments of the potential risks posed by chlorpyrifos, and determined that many registered uses of chlorpyrifos potentially pose unacceptable levels of risk, especially to children. The Agreement uses a phaseout approach that ceases production of the riskiest uses first. Ultimately, it will eliminate the following uses of chlorpyrifos: all termite control uses; all residential uses (except for ant and roach baits in child-resistant packaging and certain public health uses); all indoor nonresidential uses (except use on ship holds, industrial plants, manufacturing plants, food processing plants, and containerized baits in child-resistant packaging); all outdoor nonresidential uses (except use on golf courses, road medians, industrial plant sites, nonstructural wood treatments, and fire ant mound drenches and mosquito control for public health purposes); and use on tomatoes and post-bloom apple trees. This Dialogue begins with a brief overview of the statutory and regulatory setting that provided the foundation for the Agreement. It then goes on to discuss the negotiations leading up to the Agreement, the Chlorpyrifos Agreement itself, and the resulting aftermath.