2. Relevance to Public Health 2.1 Background and Environmental Exposures to Guthion in the United States

Guthion, a trade name for azinphos-methyl, is a restricted use organophosphate insecticide that is primarily used as a foliar application against phytophagous insect pests on fruit, field, or vegetable crops and works as both a contact insecticide and a stomach poison. In 2002, the estimated annual agricultural use of guthion had declined to about 1.2 million pounds, nearly a 50% decline from 1997 usage data. The total amount of guthion reportedly used in 1997 was 2,091,014 pounds, which was an 18% decrease from the amount used (2,548,867 pounds) in 1992. In the Interim Registration Eligibility Decision (interim RED) document for guthion, EPA estimated that <2 million pounds are used annually. The greatest amounts of guthion have historically been applied to orchard fruits such as apples, pears, cherries, and peaches; however, guthion has also been used extensively on cotton, almonds, sugarcane, and several other crops. The uses of guthion have been severely restricted in recent years. In 2001, the EPA proposed the immediate cancellation of most uses of guthion. Currently, the only crops that guthion can still be applied to are: almonds; apples/crabapples; blueberries, lowbush and highbush; Brussels sprouts; cherries, sweet and tart; nursery stock (woody shrubs, vines, seeding trees, and nonbearing fruit trees); parsley; pears; pistachios; and walnuts. On June 9, 2006, EPA proposed the cancellation of guthion for apples, blueberries, cherries, parsley, and pears by 2010 and a phase out of guthion’s other uses by the end of 2007. On August 8, 2007, the companies that produce guthion advised the EPA that they intended to amend their registrations to terminate certain uses (Brussels sprouts and nursery stock) of guthion by September 30, 2007. Uses on walnuts, almonds, and pistachios are scheduled to cease by October 30, 2009, and all other uses would be terminated by September 30, 2012.