Methyl Iodide

Methyl Iodide (MeI) is an example of a highly toxic compound under investigation by STPP. We are investigating the toxicity of MeI as an agricultural fumigant, with plans to conduct an alternatives analysis and review policy issues regarding its use.

Methyl iodide is a highly reactive chemical used in some industrial processes and in research laboratories for the synthesis of new molecules. Alkylating agents like MeI are well-known cancer hazards. Because of MeI's high volatility and water solubility, broad use of this chemical, such as in agricultural production, will guarantee substantial releases to air, surface waters, and groundwater, and will result in exposures for many people. Despite this, manufacturers of MeI are requesting that MeI be approved for use as an agricultural fumigant.

The Montreal Protocol, the 1989 international treaty designed to ban substances shown to deplete stratospheric ozone, stands as one of the most effective risk prevention statutes ever enacted. One such ozone-depleting substance is methyl bromide (MeBr), a fumigant used to control pests across a wide range of agricultural sectors. Methyl iodide (MeI) has been proposed by its manufactures as an ideal replacement for MeBr and has petitioned U.S.EPA and the California EPA’s Department of Pesticide Regulation (DPR) to be registered for use.

STPP’s Dr. John Froines was asked by the California EPA's Department of Pesticide Regulation (DPR) to chair a Scientific Review Committee to evaluate the heath risk assessment of MeI. In February 2010, the SRC issued its final report which found MeI to be a highly toxic chemical, and when used as intended, would have a significant adverse impact on the public health.

Despite the SRC findings, DPR proceeded forward with the process of registering MeI. California Senate Food and Agriculture Committee, which oversees the DPR, called a legislative hearing, where Dr. Froines described MeI as “ one of the most toxic chemicals on earth” and Dr. Theodore A. Slotkin of Duke University Medical Center warned that the approval made children of the state of California into “test animals.”

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