Methyl iodide is a chemical used to create cancer cells in the laboratory. It's also a substance that California farmers hope to use to grow those big and beautiful supermarket strawberries. By killing most everything in the soil to clear the way for food crops, the pesticide helps fragile strawberries thrive. But methyl iodide's toxicity has raised a storm of controversy over potential health impacts since the U.S. Environmental Protection Agency approved it for agricultural use in 2007.
EPA approved methyl iodide at the end of the Bush administration to replace the ozone-depleting (but less toxic) methyl bromide. The approval went forward despite public outcry, including a letter from over 50 scientists, stating: "It is astonishing then that the Office of Pesticide Programs is working to legalize broadcast releases of one of the more toxic chemicals used in manufacturing into the environment."
Despite federal approval, some states still have doubts about the chemical. New York and Washington State have denied state approval of the fumigant based on concerns about impacts to health and the environment.
California, whose $2.1 billion strawberry industry would become the nation's largest user of the chemical, approved the stuff last December as Governor Schwarzeneggar left office, despite the recommendations of its own scientists to the contrary. The state was promptly sued by health and environmental groups.
That 2009 study by the California Department of Pesticide Regulation jumpstarted the effort to reverse course on methyl iodide, cautioning that widespread use “would result in exposures to a large number of the public and thus would have a significant adverse impact on the public health,” and that “adequate control of human exposure would be difficult, if not impossible.” The first permits to spray methyl iodide in California are now pending.
After its 2007 decision, EPA had said it would re-open its methyl iodide decision if the California study found new risks from the chemical, which, petitioners argue, it did. Up to this point, however, no federal action has been taken.
The manufacturer, Tokyo-based Arysta LifeScience, claims methyl iodide has been used in southeastern states with no harm to workers.
But the National Institute for Occupational Safety and Health calls methyl iodide a potential human carcinogen. Reproductive and neurological problems are also a concern, as well as the potential for groundwater contamination. Meanwhile, the World Health Organization's International Agency for Research on Cancer, considered a definitive source on cancer-causing substances, says methyl iodide is "not classifiable as to its carcinogenocity to humans" due to a lack of research on the subject.
Everybody loves cheap, delicious, flawless strawberries. But all of the controversy surrounding methyl iodide begs the question: At what cost?
Nathan Rice is a HCN intern.
Photo courtesy Flickr user ceratosaurrr.