The Second Circuit Court of Appeals has granted, in part, the petition for review filed against the Environmental Protection Agency (EPA), challenging its risk assessments for the pesticide dichlorvos. NRDC v. EPA, No. 08-3771 (2d Cir., decided September 16, 2011). The court agreed with the Natural Resources Defense Council, (NRDC) that EPA’s failure to explain why a children’s safety factor less than 10X was applied to pesticide risk assessments derived from the “Gledhill study,” which involved six adults who consumed dichlorvos daily for three weeks, was arbitrary and capricious. When EPA sets tolerances for the maximum level of dichlorvos residue on food products, it is required, under the Food Quality Protection Act, to apply a tenfold children’s safety factor. Vacating the portions of EPA’s order assessing the risk of dichlorvos based on the Gledhill study, the court remanded the matter to the agency for further proceedings.

EPA has registered a number of dichlorvos products for sale and distribution in the United States. According to the court, it is “a synthetic pesticide used to kill many insects, including flies, mosquitos, gnats, cockroaches, and fleas. Dichlorvos belongs to a family of pesticides known as organophosphates, developed from nerve warfare agents after World War II. Like other organophosphates, dichlorvos can disrupt proper functioning of the nervous system by inhibiting an important enzyme, cholinesterase, in red blood cells and the brain.” EPA, at one time, considered requiring a cancer warning on dichlorvos products, which are used on crops, animals and in pest strips to control insects in storage areas and barns.