After years of international pressure, the U.S. is finally forcing growers to cease their use of methyl bromide, an iodorless and invisible chemical that has been found to be a major depleter of the earth's ozone layer.  In a scramble to find a replacement for this widely-used pestiocide, scientists have settled on methyl iodide.  While methyl iodide does not pose the same threat to the ozone layer as methyl bromide, it is perhaps even more toxic for humans.    Methyl bromide is widely used on Florida's tomato and strawberry crops.  The following article shows the struggle in California over whether the state will permit methyl iodide to be used as a replacement for methyl bromide.  Florida will have to make a similar decision soon.  Worker advocates may well want to monitor the handling of this issue by Florida's Department of Agriculture and Consumer Services.



September 24, 2009


Panel assessing state's analysis of methyl iodide risk

SACRAMENTO — A panel of eight independent toxicologists from research institutions across the country began work Thursday in assessing whether state regulators have accurately analyzed the potential risk of allowing a controversial new soil fumigant to be used in California.

The panel will make no direct recommendation on whether the California Department of Pesticide Regulation should allow methyl iodide to be used on strawberries and other crops, but its evaluation of the risk assessment conducted by state scientists could be critical in shaping the department’s final ruling, expected by the end of the year.

In a statement last month, department Director Mary-Ann Warmerdam said the risk assessment will “serve as the basis” for the state’s decision.

Methyl iodide is seen by farmers as a potential replacement for methyl bromide, a commonly used soil fumigant whose use is being phased out internationally because it contributes to damage of the Earth’s ozone layer.

The assessment by the state scientists concludes that methyl iodide poses a “significant” health risk for workers.

Because strawberries are such a significant crop, use of methyl bromide in Ventura County is among the greatest of any county in the nation. State data show that in 2007, 835,000 pounds of the fumigant were applied over 4,634 acres here.

The federal Environmental Protection Agency authorized the use of methyl iodide in the United States two years ago, but California has a separate process for certifying a pesticide for use in the state.

Environmental groups and farmworker advocates have lobbied against registering methyl iodide in California, arguing it is a strong carcinogen and also puts those exposed to it at risk of thyroid disease and potential miscarriages.

Scientists for the Pesticide Action Network and the California Rural Legal Assistance Foundation are expected today to challenge some of the findings of the department’s risk assessment in testimony before the independent panel of scientists.

Also scheduled to testify are seven scientists affiliated with Arysta LifeScience Corp., the company that manufactures methyl iodide for pesticide use under the brand name Midas. In addition, the panel will hear from two scientists with the federal EPA.

In Thursday’s opening session, the panel heard from the state scientists who prepared the department’s risk study. The assessment looks at exposure levels to field workers, bystanders and residents of homes near fields that have been treated. It notes that laboratory tests on animals have shown fetal deaths, neurotoxicity and thyroid tumors are the most critical concerns.

It concludes that the application of methyl iodide “in field fumigation under the conditions evaluated results in significant health risks for workers and the general population.”

The review panel is chaired by John Froines, director of the Center for Occupational and Environmental Health at UCLA, and includes researchers from UC San Francisco, UC Berkeley and Boston, Clark and Duke universities.

“The panel is charged with a very difficult task,” Froines said in opening remarks Thursday. “Everybody in the audience should rest assured that you’re going to get the best science.”