Methyl Iodide: The Cancer-Causing Chemical Behind Your Food

Despite protests, the EPA approved the use of this potent poison years ago, but a lawsuit moving through the courts could change that.


When researchers want to intentionally create cancerous cells in laboratories, they often use methyl iodide, a chemical that is also a neurotoxin and causes late-term miscarriages. And it kills soil-dwelling organisms -- which is why farmers (particularly strawberry and tomato growers) fumigate fields with it prior to planting.

Calling it one of the most toxic chemicals used in manufacturing, more than 50 scientists, including five Nobel laureates, wrote a letter (PDF) to the Environmental Protection Agency (EPA) toward the end of the Bush II administration pleading that methyl iodide not be approved for agricultural use. To no avail. They failed in California, too, which sets its own environmental regulations, independent of the EPA. But the state followed the EPA's lead and approved it in 2010, just before Governor Schwarzenegger left office.

Last year, lawyers from Earthjustice and California Rural Legal Assistance, Inc. filed suit challenging the chemical's approval on behalf of several environmental and farmworkers groups, who claimed that California officials approved the fumigant despite warnings from scientists in the state's own Department of Pesticide Regulation. Earlier this month, the case came before the Alameda County Superior Court.

"Nobody disputes that methyl iodide is a potent poison," Earthjustice lawyer Greg Loarie said in a press release. "By approving the cancer-causing pesticide, California's pesticide regulators ignored the science and broke important laws designed to protect public health." Farm laborers and residents of rural areas -- particularly children -- are most at risk to exposure to methyl iodide, which can be carried on the wind.

Methyl iodide has made no shortage of enemies since being approved. In addition to labor and environmental organizations, their numbers include 35 California legislators who signed a letter last April asking the EPA to "suspend and cancel" all uses of methyl iodide in the United States. At about the same time, the current governor of California, Jerry Brown, promised to reconsider the state's decision to register methyl iodide. The EPA has opened a public comment period on a petition, asking it to ban methyl iodide, and so far more than 200,000 citizens have written in support of the ban.

In an email to me following an earlier post I wrote, Arysta LifeScience, the manufacturer of methyl iodide, claimed that the chemical is naturally occurring and produced by marine algae. The company said that methyl iodide has been used as a fumigant in the southeast United States since 2007 without a single safety incident reported.

Judge Frank Roesch, who is hearing the California case, is showing that he is no pushover. According to a press release from Pesticide Action Network North America, a plaintiff in the California case, the judge said he found no evidence that the state officials had ever considered not approving methyl iodide. Without such evidence, the judge said that he could not see how the state could "prevail in this lawsuit."

We'll see if he still feels that way in a few months, when a decision is expected.

Image: karamysh/Shutterstock.

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Barry Estabrook is a former contributing editor at Gourmet magazine. He is the author of the recently released Tomatoland, a book about industrial tomato agriculture. He blogs at More

Barry Estabrook was formerly a contributing editor at Gourmet magazine. Stints working on a dairy farm and commercial fishing boat as a young man convinced him that writing about how food was produced was a lot easier than actually producing it. He is the author of the recently released Tomatoland, a book about industrial tomato agriculture. He lives on a 30-acre tract in Vermont, where he gardens and tends a dozen laying hens, and his work also appears at

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