Methyl iodide, a fumigant under fire
PESTICIDE ACTION NETWORK NORTH AMERICA
Kegley, CEO of the Pesticide Reministration, Bergman and California just completed an assearch Institute, a consulting firm. Hoffmann reiterated their concerns sessment which indicates that the EPA generated lower exposure February 3, 2009, to EPA’s new adpesticide methyl iodide presents estimates because it assumed that ministrator Lisa Jackson. EPA resignificant health risks to farm releases of methyl iodide would plied April 6 that it would roll the workers. The U.S. Environmental diffuse equally in all directions reevaluation of all fumigants, inProtection Agency (EPA) approved around a field and made calculacluding methyl iodide, forward by the use of methyl iodide in 2008, tions based on average air concenfour years to 2013. “However, deafter ignoring calls from leading trations over 24 hours, scientists for an indepenKegley says. California’s dent review. The pending assessment takes wind diregistration of methyl iorection into account and dide in California will looks at the air concentrahave to wait for an extertions on the downwind nal scientific review, sides of fields as a worstwhich observers predict case scenario. Because will have a significant imthere are so many uncerpact on policy, this fall. tainties about the impacts Methyl iodide was develof methyl iodide, especially oped to replace methyl on developing fetuses, bromide, a fumigant that is CDPR used an uncertainty applied to soil to kill pests factor that is 10 times larger before crops such as strawberries, fruit vines, and The new pesticide methyl iodide would be applied the same than EPA’s to estimate an acceptable dose of pestinursery trees are planted. way as methyl bromide, shown here, but with graver consequences for human health, according to a draft risk as- cide. California’s draft risk Because methyl bromide sessment from California. assessment concludes that destroys the ultraviolet“air concentrations estimated for hupending on the outcome of Califorshielding ozone layer in the upper man exposure to [methyl iodide] unnia’s external peer review and final atmosphere, the chemical is being der the proposed use conditions will risk assessment, EPA may choose phased out under the Montreal result in significant risks for workers to initiate reevaluation of the methProtocol on Substances that Deand the general population, with anyl iodide registration even sooner,” plete the Ozone Layer. Methyl ioticipated exposures up to 3000 times the agency added. dide does not damage the ozone the acceptable dose for some proOn April 21, EPA gave Arysta layer, but California has identified posed soil-fumigation-use scenarios.” LifeScience Corp., the maker of it as a carcinogen, neurotoxin, and Behind-the-scenes lobbying by methyl iodide, an Ozone Layer Proendocrine disruptor. industry had critics of methyl iotection Award for the pesticide. “Methyl iodide is potentially dide worried that CDPR would reg“We were upset and perplexed by harmful to human health because ister the pesticide this summer and the EPA’s decision to give an award it is used in the lab as an alkylating cancel an external scientific review to a company the safety of whose agent and is therefore likely to of the risk assessment; the review product was being questioned,” cause mutations in biological molwas set to begin in September. But Hoffmann says. EPA replied that the ecules such as DNA and proteins, ” after 27 California assembly memaward was made because methyl explains Robert Bergman, a chembers wrote Governor Schwarzenegiodide will help the U.S. reduce its ist at the University of California ger on July 29, 2009, asking for reliance on methyl bromide, the last Berkeley. Bergman and Roald HoffCDPR to delay a decision until the remaining highly ozone-depleting mann, a Nobel laureate chemist at external review was completed, substance in widespread use. Cornell University, enlisted more CDPR announced the same day EPA’s hands-off approach has than 50 distinguished scientists, that the review would go ahead. critics of methyl iodide looking for most of them members of the NaThe independent scientific releadership from California, which is tional Academy of Sciences, to sign view of methyl iodide is necessary the largest potential market for the a letter in 2007 asking EPA not to to avoid even an appearance of a chemical. The California Departpermit use of the chemical until conflict of interest, Bergman says. ment of Pesticide Regulation EPA’s risk assessment had been (CDPR) has completed a draft risk reviewed by an independent panel. —JANET PELLEY assessment that seriously disagrees After receiving a defensive rewith EPA’s assessment, says Susan sponse from George W. Bush’s ad6898 9 ENVIRONMENTAL SCIENCE & TECHNOLOGY / September 15, 2009
10.1021/es9023095
2009 American Chemical Society
Published on Web 08/04/2009
