Salinas - When Annette Danzer and her husband moved into a house surrounded by brush and strawberry fields on California's Central Coast, they were drawn by the rural feel and closeness to nature.

Three years later, the couple fears the fields near Salinas could become a health threat due to potential use of the pesticide methyl iodide.

California regulators approved use of methyl iodide in December despite opposition from scientists and environmental and farmworker groups who claim it's highly toxic and can cause cancer. The chemical would likely be used primarily in California's $2 billion strawberry industry, which last year produced nearly 90 percent of the nation's strawberries on over 37,000 acres.

Danzer and her husband have moved their 10-year-old son, Luke, out of a nearby elementary school because it's close to fields that could be fumigated, and Danzer joined hundreds of thousands of others in submitting comments or signatures to the U.S. Environmental Protection Agency regarding a petition seeking to block use of the chemical. The deadline to comment on the petition, filed by the environmental group Earthjustice, is Friday, but it's unclear whether the EPA will take any action.

"We are really concerned about methyl iodide," said Danzer, who now drives her son 45 minutes to another school. "This is not just strictly a farmworker issue. The fields are walking distance to homes and schools. The fields are in our watershed."

In April, 38 California legislators - led by Democratic Assemblyman Bill Monning of Monterey - sent a letter asking the EPA to pull the chemical off the market and reopen its scientific evaluation. They cited scientists who found "there is no safe level of use for methyl iodide" for workers and rural residents. It's not considered a risk for consumers because it's injected into the soil to kill pests before crops are planted and not applied directly to fruits and vegetables.

"I have the utmost respect for the challenges of our grower community faces," Monning said. "But my fear is that this chemical is so unstable and so toxic, it's not a question of whether there will be a tragic accident, the question is when."

Last month, Ventura County officials withdrew the state's first permit for the fumigant a day after granting it to an Oxnard-area farmer. County officials said the permit was withdrawn after they learned the farmer's fields were less than a half-mile from a playground.

Gov. Jerry Brown has also said his administration would take "a fresh look" at state regulators' decision to approve the fumigant.

The EPA first approved methyl iodide in 2007 as a replacement for another fumigant, methyl bromide, which is being phased out by international treaty because it depletes the Earth's ozone layer. Methyl iodide is now registered in 47 other states. The chemical kills bugs, weeds and plant diseases and is used by some growers of tomatoes, peppers and other crops.

A range of scientists agreed on the toxicity of methyl iodide during California's review of the fumigant. When California's Department of Pesticide Regulation registered the chemical, it overruled its staff's scientific review and one by an external scientific panel. Those scientists concluded that use of the fumigant would result in acute public health risks because tests on rats and rabbits have shown that airborne exposure to the chemical causes thyroid cancer, miscarriages and damage to the nervous system. Scientists also found it can pollute air and water.

Earthjustice wants the agency to consider California's scientific risk analysis.

"Our opinion is that the EPA can't just ignore this evidence that we've put in front of them," said Earthjustice attorney Greg Loarie. "So rarely do you have a situation when scientists are so unanimous."

Jeff Tweedy, head of business development in North America for Arysta LifeScience Corp., the Tokyo-based pesticide giant that markets methyl iodide under the brand name Midas, said the scientists who reviewed the fumigant for California "just got it wrong. This product has been proven in the field and it can be used safely."

Regulators insist precautions - which include half mile buffer zones from schools, the use of special tarps to keep fumes from escaping and the use of respirators for workers - make the use of the fumigant safe. But Monning said precautions don't factor in wind and human error.

Maria Puga, a former Salinas farmworker who signed the petition, said many workers don't know when growers use chemicals, because they are busy working and don't speak English. As a result, they won't know when or how to protect themselves. Puga is concerned the fumigant will affect her six grandchildren who attend school near fields, relatives who pick strawberries and a daughter who lives near a strawberry field.

"These chemicals will affect us all, our schools, our kids," she said in Spanish. "We need to let people know about it."

Growers who submitted comments on the petition claim that without the fumigant, production of California's sixth most valuable fruit crop may suffer.

"It's one tool out of many that growers should be able to use, and like every tool there are appropriate and inappropriate uses," California Strawberry Commission spokeswoman Carolyn O'Donnell said. Other fumigant alternatives, O'Donnell said, are not as effective.

In recent years, the Strawberry Commission has poured more than $12 million into university research to look at alternatives to fumigation, such as crop rotation, eliminating soil pathogens by using natural sources of carbon and sterilizing soil with steam.

"There's a mindset among growers that chemicals are the way to go," said researcher Carol Shennan, a professor at the University of California, Santa Cruz. "I see the research we're doing as challenging that mindset and saying there may be other alternatives out there."