Pesticide manufacturers have tested pesticides increasingly in human volunteers over the past decade. The apparent goal of these human studies is to establish threshold levels for symptoms, termed "no observed effect levels." Data from these studies have been submitted to the U.S. Environmental Protection Agency (EPA) for consideration in standard setting. There are no required ethical guidelines for studies of pesticides toxicity conducted in humans, no governmental oversight is exercised, and no procedures have been put in place for the protection of human subjects. To examine ethical and policy issues involved in the testing of pesticides in humans and the use of human data in standard setting, in February 2002 the Center for Children's Health and the Environment of the Mount Sinai School of Medicine convened an expert workshop for ethicists, physicians, toxicologists, and policy analysts. After a peer consensus process, participants developed a number of ethical and public policy recommendations regarding the testing of pesticides in humans. Participants also strongly encouraged active biomonitoring of every pesticide currently in use to track human exposure, particularly in vulnerable populations, and to assess adverse effects on health.