The Environmental Protection Agency on Friday delayed approval of a new toxic fumigant for use by fruit and vegetable farmers, after more than 50 prominent scientists objected that the chemical was too dangerous.
The agency said previously that a decision would be announced by Friday about methyl iodide, also called iodomethane. But in an unexpected move, it said officials "will address recent questions prompted by the pending registration of iodomethane."
The EPA received a letter this week from 54 scientists, including six Nobel Prize winners, who said they were astonished EPA was considering approving such a toxic chemical for agricultural use.
"The gratifying thing is that EPA has been responsive to people who are really concerned about this," said Robert Bergman, a University of California at Berkeley professor who organized the scientists' letter. The letter criticized EPA's scientific analysis, calling for an independent scientific review of the agency's assessment.
The fumigant was developed to replace the highly effective fumigant methyl bromide, which is banned by an international treaty because it depletes the earth's ozone layer. Both fumigants are injected into soil before planting and do not leave a residue on the produce itself. Critics have cited cases where fumigant fumes escaped from soil and harmed farmworkers or nearby residents.
"EPA's analysis of iodomethane is one of the most thorough analyses ever completed on a pesticide and we welcome the opportunity to allow interested parties a better understanding of the scientific analysis supporting the evaluation," said the brief statement from EPA Assistant Administrator James Gulliford.
EPA spokesman Dale Kemery would not elaborate on the decision nor provide any new timetable for the agency's decision.
The registration would have allowed farm use of MIDAS, a new fumigant containing methyl iodide and developed by Tokyo-based Arysta Life Science Corp., to kill insects, weeds and soil-borne diseases that affect a wide range of crops such as tomatoes, strawberries, peppers and eggplant.
It was the second time EPA has hedged on methyl iodide. Last year, after California state regulators, environmental and farmworker groups and some of EPA's own scientists voiced disagreement, EPA declined to move ahead with registration and said it would consider the matter this year. The Associated Press publicized the scientists' letter earlier this week and the agency's plans to announce its decision.
"There's been enough controversy over this chemical that they should seriously consider never registering it at all," said Susan Kegley, senior scientist for the Pesticide Action Network of North America.
Critics said use of methyl iodide is complicated by its combination with chloropicrin, another soil fumigant that sickened some 125 farm workers who breathed it on Thursday near Reno, Nev.
California classifies the fumigant as a carcinogen, and regulators have expressed concern about its safety as an agricultural product. Studies also show chronic exposure can harm the central nervous system, lungs, skin and kidneys. The California Department of Pesticide Regulation is conducting its own review of methyl idodide and would not likely rule on its use in the state for at least a year regardless of EPA's ultimate decision, said spokesman Glenn Brank.
California, where strawberry farmers relied heavily on methyl bromide and are trying a variety of less effective alternatives, is allowing small trials with methyl iodide, as are some other states. The California Strawberry Commission said Friday its growers will not use any pesticide until it has been approved by federal and state regulators.