The U.S. Environmental Protection Agency has withdrawn its plan to approve a highly toxic fumigant for strawberries and other high-value crops after California officials, labor unions, environmentalists and others objected that nearby residents and farmworkers could be in danger.
The new pesticide, methyl iodide, is designed to replace methyl bromide, which is banned under an international treaty because it damages the Earth's ozone layer.
Strawberry growers, concentrated mostly in Ventura and Santa Cruz counties, have been searching for nearly 15 years for a fumigant to replace methyl bromide, which they have been phasing out but are still using under exemptions granted by the United Nations. Facing criticism that it was substituting one dangerous chemical for another, the EPA decided not to register methyl iodide, also known as iodomethane. It will reevaluate the pesticide next year.
"EPA's refusal to automatically approve the use of another dangerous chemical as an alternative to methyl bromide is encouraging," said Susan Kegley, senior scientist at the environmental group Pesticide Action Network North America. "They didn't knock it out for good, but it's a good sign that they are holding off."
Fumigants are considered particularly risky among agricultural pesticides. But they also are valuable to growers because a single injection into the soil before planting will sterilize the field and destroy an array of insects, weeds and diseases.
The new pesticide, a gas, does not leave residue in food. But it does evaporate from the soil, exposing farmworkers during application, and small amounts can drift off fields into nearby communities. In animal tests, breathing large doses of methyl iodide killed fetuses, caused thyroid tumors, damaged respiratory tracts and altered thyroid hormones, which can disrupt the development of infants' brains.
Scientists at the California Department of Pesticide Regulation raised numerous health concerns about methyl iodide, which the state has declared a cancer-causing chemical.
"While residues may not be present in crops grown in treated soil, workers and bystanders, as well as residents living near the treated fields, will be exposed to it in the air," Tobi Jones, an assistant director at the state agency, told the EPA in a letter.
Ventura County Supervisor Steve Bennett, acknowledging that a substitute for methyl bromide is "desperately needed" by farmers in his county, was among those who contacted the EPA to oppose the new pesticide because he considered the EPA's evidence of its safety for nearby communities inadequate.
The EPA received about 13,000 such letters, mostly in campaigns led by environmental groups and the United Farm Workers. "Rural communities have repeatedly been poisoned by existing fumigants," UFW letters said. "It is time to move to much safer methods of pest control, not backwards to a chemical that is even more toxic."
Other pesticide companies also objected. Methyl bromide manufacturers complained that the EPA was requiring looser safety precautions for methyl iodide than it did for the chemical it would replace. They said the agency inadequately addressed risks of neurological damage to infants and children near the fields.
The EPA said in a statement Tuesday that it decided not to register iodomethane because of "the uncertainty associated with the risks and benefits."
EPA spokeswoman Enesta Jones said the agency will reevaluate the chemical after it completes a review of all fumigants. "At that time, the agency can better determine if iodomethane is a viable replacement for methyl bromide," Jones said.
The manufacturer, Arysta LifeScience Corp., said it has not given up on its new chemical, which it plans to market under the name MIDAS.
Tokyo-based Arysta has spent seven years and more than $11 million collecting toxicological and environmental data to persuade the EPA to register methyl iodide for use on strawberries, tomatoes, peppers, ornamentals, grapes and several other crops.
"We were disappointed that the EPA did not register [methyl iodide] at this time. However, Arysta LifeScience remains confident, and we are committed to the long-term success of this product for growers and the industry," Arysta spokeswoman Donna Uchida said. "We are developing additional scientific information for the EPA to have full confidence that the use of MIDAS presents no unreasonable risk and is a legitimate, commercial replacement for methyl bromide."
California -- particularly the Oxnard and Watsonville areas -- has a lot at stake in the search for a new fumigant because the state produces 88% of the nation's strawberries, worth about $1.3 billion last year.