Even the innocent must someday grow up, and the cold taint of controversy has slithered its way into the strawberry fields. The Beatles dreamed of "Strawberry Fields Forever," as a place of refuge and escape from worldly complexities in our collective imagination. Strawberries have symbolized purity for years. But a new chemical proposed for systemic fumigation of strawberry fields has put the fruit's sweet poison back in the spotlight. Strawberries have become a point of contention between anti-pesticide advocacy groups, who disapprove of the use of methyl iodide as a fumigant, and the California Department of Pesticide Regulation, which maintains that it is mostly harmless.

Most scientists agree that widespread application of methyl iodide to strawberry fields poses a risk to the health of field workers and nearby residents. Methyl iodide is listed as a carcinogen in California's Safe Drinking Water and Toxic Enforcement Act of 1986 (Proposition 65), which catalogues chemicals known to harm human health. In fact, cancer researchers use methyl iodide on lab animals when they need to induce cancer-cell production. More toxic than methyl bromide—which is the currently favored fumigant—methyl iodide can cause thyroid cancer and birth defects. It can disrupt thyroid hormones, metabolic processes and immune response. A known neurotoxin, it can slowly erode cognitive abilities.

While large-scale farmers claim that they need a fumigant to sterilize the soil, organic farmers manage in nontoxic ways. Anaerobic soil disinfestations, treating soil with steam, and rotating crops protect them from pests without killing everything in the soil. Susan Kegley, consulting scientist for Pesticide Action Network North America (PANNA) and owner of her own private consulting business, Pesticide Research Institute, explains that fumigants kill some organisms that actually help strawberries grow, such as nematodes that eat "bad guy" nematodes and bacteria that hinder fungal growth.

James J. Sims, UC Riverside chemistry professor who pioneered methyl iodide as an alternative fumigant, counters that organic farming methods don't work, especially not on an industrial scale. "We still have to have food, and it doesn't grow at the supermarket," he says. "Not in the amounts we need."

First proposed in 2002 as an alternative to the ozone-depleting methyl bromide, methyl iodide gained national legality in 2007 when the Environmental Protection Agency approved the chemical for agricultural use in the United States. California happens to be one of the few states that requires a separate approval process before new pesticides enter the market.

The Department of Pesticide Regulation (DPR) asked its consulting scientists to run risk-management tests. They then employed a committee to check the DPR scientists' work. The Scientific Review Committee deemed methyl iodide unsafe due to the tight restrictions necessary to control its use. Their risk-management assessment advised slightly stricter regulations than the DPR suggestions, but the difference was not substantial. Both the DPR scientists and the Scientific Review Committee recommended barring registration of methyl iodide. But the DPR ignored its own scientists and moved ahead with the registration process.

The DPR scientists cautioned state regulators to limit methyl iodide exposure to 0.8 parts per billion, but the current proposal allows 96 parts per billion, which is itself a reduction from the 193 parts per billion allowed by the EPA. In an attempt to reduce risk beyond the shockingly lax EPA regulations, the DPR has not only lowered the legal exposure level but also requires permits for users, larger buffer zones of 100 to 2,500 feet, wider buffer zones around schools and hospitals, virtually impermeable film tarps for post-treatment coverage, fewer acres fumigated at once, time-of-day application limitation, fewer pounds per acre, more stringent groundwater precautions and a longer period of time between treatment and workers returning to the field. "If you use the right precautions and strict supervision, it's a safe chemical to use," Sims says.

But Megan Buckingham of PANNA is not convinced. "No restrictions would make it safe for use as a pesticide," she says. "The DPR would like the public to believe they can manage the risk and are able to do so taking science into account. But if you look at what they propose, it's not safe."

Don't expect the distance from central valley strawberry fields to save Sonoma, Napa or Marin counties. If California approves methyl iodide, the chemical will also be used in vineyards and orchards.

Part of PANNA's concern about methyl iodide stems from the limited empirical research on the chemical's long-term effects when used in agriculture. "It actually hasn't been studied very thoroughly [as an agricultural pesticide]," Buckingham says. "California would be the largest market for methyl iodide."

That's quite the bushel of responsibility. Southeastern states such as Florida, Georgia, North Carolina and South Carolina are home to an abundance of strawberry and tomato fields, and have used methyl iodide as a fumigant since the EPA approved it in 2007. In a letter to the editor of Nature magazine, Sims pointed out that methyl iodide "has been applied to more than 15,000 acres [in the southeast], in fact, with no adverse incidents."

As far as is known. Still, anti-pesticide activists maintain that the kind of effects they expect to see from methyl iodide involve long-term complications, such as cancer and developmentally delayed children, that may take time to become obvious. Kegley evokes the three wise monkeys: see no evil, hear no evil and speak no evil. "Nobody's looking," she says. "Arysta [the pesticide company with which methyl iodide is registered] is supposed to be monitoring the groundwater, but they're not doing it."

Kegley points out another oversight the EPA made when testing methyl iodide safety. "The EPA did not require a developmental neurotoxicity test." After other tests deemed the chemical unlikely to cause fetal death at the proposed rates of exposure, the EPA did not take the next step and examine possible damage to fetuses. Since the concentration of methyl iodide that induces developmental problems will be lower than the concentration that causes fetal death, the EPA's control concentration number protecting against fetal death may do nothing to protect fetuses from the chemical's ability to inflict developmental delays.

Unlike methyl bromide, methyl iodide is applied as a liquid. Sims says this makes it "easier to handle than gases, because you can tell where it is." Kegley points out that methyl iodide volatizes quickly when removed from the tank and reverts to its natural state as a gas. In this form, the chemical could endanger farmworkers and nearby residents. If approved, farmers would apply methyl iodide to the soil before strawberries are planted.

"Two weeks later, it will no longer be there," says Sims. "It will never get into the food crop." But Kegley adds that the byproduct of methyl iodide breakdown is the iodide ion, which the fruit may take from the soil and concentrate. "How much do the fruits that are fumigated accumulate over time?" she asks. No one knows the answer.

As a chemist with a doctorate degree, Kegley has handled methyl iodide in a lab. Cognizant of the danger it poses, she takes great care in the way in which she manipulates it. She only interacts with it under an overhead vent that ensures none of its off-gassing invades her lungs. She always wears double gloves to protect her skin, and transfers the liquid with a syringe to avoid contact with the open air. Kegley worries about farmers who are not trained in handling hazardous materials applying 125 pounds of this toxic chemical to their soil, calling the idea "ludicrous."

Sims, a former professor of chemistry, has also handled methyl iodide, but recalls a very different procedure. "I can tell you that I have used methyl iodide in the lab, off and on, for 50 years," he says. "I never used any special equipment other than a flask and pipet, and there was never a single safety incident." Was Sims just lucky?

"Methyl iodide is always in the atmosphere in small amounts, especially on the coastline," Sims says. "We're not totally defenseless."

Even though Sims assures dissenters that fumigation will only happen once a year, activists argue that it will still poison those exposed.

On Thursday, June 17, PANNA and other anti-pesticide groups attended a hearing and press conference in Sacramento. The organization presented a petition overflowing with 40,000 signatures of methyl iodide opponents to Gov. Schwarzenegger's office. Combined with the rest of the public's protests, methyl iodide is the most protested pesticide-registration decision in DPR's history, although Lea Brooks, assistant director of communications at DPR, points out that "for perspective, today's social media networks provide an easy and efficient way for the public to comment on issues."

"It's the corporations against the communities," says Kegley. "The communities next to the fields are very diverse. This is an equal-opportunity poison. And this is our one chance to keep it out of our state."

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