Food and Drink

Can methyl iodide be used as a pesticide?

Adriene Hill Dec 27, 2010
Food and Drink

Can methyl iodide be used as a pesticide?

Adriene Hill Dec 27, 2010


Bob Moon: Regulators here in California just approved the use of a controversial pesticide. And if you like strawberries, or anything with strawberries, here’s why you might care: California grows 90 percent of the country’s strawberries, and the state’s approval of this pest-killer is aimed at supporting its billion-dollar-a-year strawberry industry. No one disagrees that methyl iodide is toxic. The debate is whether or not it can be used safely.

From the Marketplace Sustainability Desk, Adriene Hill reports.

Adriene Hill: It’s a misty, gray day in Oxnard, Calif. I’m standing on the edge of 35 acres of strawberry plants.

Farmer Glen Hasagawa looks out at his field — green splashed with white flowers and a few red berries — and seems pleased.

Glen Hasagawa: They are little power plants. They’re definitely work horses.

But Hasagawa’s work horses are susceptible to disease, fungus, mold and pests. So Hasagawa uses pesticides and fertilizers to keep them producing.

Hasagawa: You know, if you have some pest outbreak in your house, the first thing you do is you pull out some ant spray or something like that, and that’s kind of what we have to do too, but on a much larger scale.

Right now, one of the tools Hasagawa uses is a fumigant called methyl bromide. But methyl bromide damages the ozone layer, and international officials got together and agreed to stop using it. So farmers are scrambling to find substitutes — and lots of them are turning to methyl iodide.

John Froines: I think this is an extremely dangerous chemical.

John Froines is a professor at UCLA. He headed a group of scientists the state asked to evaluate the chemical. Froines and his colleagues say it’s too dangerous to be used safely (PDF); it poses risk to people applying it and those who live nearby.

Froines: There were a number of case studies in which humans had been exposed to methyl iodide, and the effects of the methyl iodide were absolutely devastating.

Froines says case studies showed neurological damage. In laboratory animals, there’s also evidence of “fetal death” and cancer. So Froines and his colleagues advised the state against approving methyl iodide. But California regulators went ahead and OK’d it.

Mary-Ann Warmerdam: This particular material, methyl iodide, has been the most comprehensively reviewed material in our history.

Mary-Ann Warmerdam heads the California Department of Pesticide Regulation.

Warmerdam: We are confident that with the health protective measures that we have put in place, that it can be used safely in California.

The state allows 100 pounds of the chemical per acre, a number that makes California’s laws among the strictest. The feds are OK with nearly double that.

Warmerdam: What we look for is if certain materials, chemistries, are required for production. Can we have a reasonable degree of certainty that they can be used safely?

And really, that’s what we ask regulators to do everyday — to judge public health risk in the context of social, economic and environmental pressures.

Back out at the strawberry farm, Glen Hasagawa trusts the state to get it right.

Hasagawa: Since it is approved for use, I would be confident that we could use it safely.

Hasagawa isn’t in a rush to use the new chemical. He wants to see how other farmers are faring with it first, but he says he’s open to it. He grows some raspberries organically, but says organic strawberries just aren’t doable, at least not for what the market’s willing to pay.

Hasagawa: If we get a soil-born disease, we could lose our whole field, so we couldn’t charge enough to make it feasible for us. It wouldn’t pencil at all.

And strawberries that cost an extra 50 percent might not “pencil” for most of the rest of us; we like our food cheap. So, Hasagawa, like most other strawberry farmers, uses the tools that are available. And the state and federal government say methyl iodide can be one of those tools, even if many scientists and pesticide activists disagree.

I’m Adriene Hill for Marketplace.

MORE INFORMATION: There are two states that do not allow methyl iodide: Washington and New York. And an EPA spokesman says the agency has no plans to reevaluate its approval of methyl iodide in the immediate future. The follow are a collection of resources with information and background on the methyl iodide debate:

The California Department of Pesticide Regulation distributed a press release on the decision to register methyl iodide.

Background on California’s registration process

Information on methyl iodide from the EPA. The letter signed more than 50 scientists recommending the EPA (PDF) not allow farmers to use methyl iodide.

Information on methyl iodide from the Pesticide Action Network

Press release about California’s decision to allow methyl iodide from the chemical maker, Arysta Life Science.

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