Department of Pesticide Regulation (DPR) Director Mary-Ann Warmerdam announced that the registration of methyl iodide will occur later this month as soon as emergency regulations take effect to designate the fumigant pesticide as a restricted material. The decision follows the U.S. Environmental Protection Agency’s (U.S. EPA) approval of California-specific labels for four methyl iodide products with stringent health-protective measures required by DPR.
Restricted materials require a use permit from the agricultural commissioner in the county where the application is planned. State pesticide laws are enforced by county agricultural commissioners, who can impose tougher restrictions tailored to local conditions.
“Methyl iodide is the most evaluated pesticide in the department’s history,” Warmerdam said. “Methyl iodide can be used safely under our tough restrictions by only highly trained applicators at times, places and specific conditions approved by the county agricultural commissioners.”
California’s use restrictions on methyl iodide are more stringent than those required by U.S. EPA, Florida and other states where it is applied. U.S. EPA registered methyl iodide in 2007 as a replacement for methyl bromide, which causes damage to ozone in the upper atmosphere.
Methyl iodide does not harm the ozone layer.
Methyl iodide will be legal for use in California after the emergency regulations take effect in late December. The emergency regulations are necessary so methyl iodide can only be used with a permit from the county agricultural commissioner.
DPR received more than 50,000 public comments after Warmerdam proposed registration of methyl iodide in April. Most of the comments expressed concern about potential health risks from methyl iodide applications.
“We acknowledge there are strong and diverse opinions on methyl iodide registration,” Warmerdam said. “Methyl iodide is a chemical designed to kill pests and soil-borne diseases. We based our decision on the risk assessment by our scientists and a risk-management process that determined what measures are required to keep exposures to methyl iodide within safe levels. With these safeguards, methyl iodide can be used without exposing workers and the public to harmful levels.”
Since DPR announced its proposal to register methyl iodide in April, the use restrictions have been clarified and strengthened, including stricter buffer zones, a requirement that only DPR-approved highly retentive tarps be used, more ground water protections, reduced application rates and stronger protections for workers.
In addition, as part of its obligation to continuously evaluate all registered pesticides, DPR will conduct sampling of water and soil in areas with high methyl iodide use to monitor the effectiveness of the mitigation measures.
Methyl iodide, also called iodomethane, is licensed for use in 47 other states. Injected into soil before crops are planted, the fumigant spreads through the soil to kill weed seeds, plant diseases and nematodes. It can be applied by drip irrigation under a special protective tarp or injected into the soil using a tractor that automatically places a tarp over the ground after application.
Methyl iodide products are made by Arysta LifeScience Corp. and sold under the brand name, Midas. The major uses of methyl iodide in California are to treat soil where strawberries, nursery plants and nut trees are to be planted. Since U.S. EPA considers methyl iodide a feasible alternative to methyl bromide, the federal agency is expected to approve less methyl bromide for use in the state under provisions of the Montreal Protocol. This treaty is designed to phase out methyl bromide to protect the ozone layer.
DPR will submit its request for emergency regulations that will make methyl iodide a restricted material requiring a permit from a county agricultural commissioner to the Office of Administrative Law (OAL) on Dec. 8. The public can comment to OAL on the emergency regulations, with a copy to DPR, until Dec. 13. More information about emergency regulations is posted on OAL’s Web site at http://www.oal.ca.gov/Emergency_Regulation_Process.htm.