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Methyl iodide pulled from U.S. market

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April 11, 2012

The controversial agricultural fumigant methyl iodide has been pulled from the U.S. market, much to the relief of College of Chemistry professor Bob Bergman, who was an early and outspoken critic of its use. The Japanese firm Arysta has voluntarily halted its sale indefinitely.

Says Bergman, “Along with about 50 of my colleagues from the National Academy of Sciences, I have been raising concerns about the toxicity of methyl iodide for several years. In spite of this, and similar warnings from other chemists and toxicologists, the fumigant has been registered by both the EPA and by the California Department of Pesticide Regulation. We therefore greet the news that Arysta has taken this material off the U.S. market with substantial relief.”

Methyl iodide was first proposed as a replacement for a similar compound, methyl bromide, which depletes ozone in the upper atmosphere and was banned under the Montreal Protocol. In California, methyl iodide has been used in limited quantities on strawberries. Along with many other scientists, Bergman has cautioned that methyl iodide has carcinogenic and neurotoxic properties, and the risks of it spreading through the air and groundwater are poorly understood.

Bergman cautions that vigilance is still needed. “Methyl iodide is still being marketed in other countries, and the fact that it is still registered here means that Arysta or other companies will continue to be allowed to use it in the future if they decide to. Many other chemicals of uncertain toxicity continue to be used and introduced in agriculture with oversight that is very minimal compared to what we require of, for example, pharmaceuticals.”

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(links courtesy of Marty Mulvihill of Berkeley Center for Green Chemistry),0,6581311.story