WATSONVILLE, California (AP) -- Farmer Vanessa Bogenholm won't go near the pesticide methyl bromide even though it could boost her strawberry harvest. But just down the coast in Salinas, grower Tom Jones says his berry farm can't survive without the powerful toxin.The two farmers both help California supply more than 85 percent of the nation's strawberries, but they part ways when it comes to methyl bromide, a soil fumigant that an international treaty has banned as of this year for all but the most critical uses.Methyl bromide continues in wide use because the Bush administration has convinced other treaty signatories that U.S. farmers can't do without it -- whether for California berries, Florida tomatoes, North Carolina Christmas trees or Michigan melons.The treaty, called the Montreal Protocol, has targeted methyl bromide because it is among chemicals that deplete the earth's protective ozone layer.It also can cause neurological damage, but methyl bromide's tenacity demonstrates the difficulty of banishing a substance that is wildly successful at delivering what both farmers and consumers want: abundant, pest-free and affordable produce.The administration, at the urging of agriculture and manufacturing interests, is pushing for continued treaty exemptions at least through 2008, and officials will not commit to an ending point.The administration's "fervent desire and goal" is to end methyl bromide's use, said Claudia McMurray, a deputy assistant secretary of state. The exemption requests are decreasing in the next two years, with golf courses, for example, making the cut this year but not next.However, McMurray said, "I can't say to you that each year the numbers (of pounds used) would automatically go down."The reason is that agriculture does not have a substitute that can match methyl bromide's stunning efficiency at destroying soil disease and pests.Odorless and colorless, methyl bromide is a gas that usually is injected by tractor into soil before planting, then covered with plastic sheeting to slow its release into the air. Eradicating parasites and disease like root rot, it results in a spectacular yield, reduced weeding costs and a longer growing season.But workers who inhale enough of the chemical can suffer convulsions, coma and neuromuscular and cognitive problems. In rare cases, they can die.Less is known about the long-term effects of low levels of contact, said Dr. Robert Harrison, an occupational and environmental health physician at the University of California, San Francisco.In Montreal Protocol negotiations, the administration used a treaty provision designed to prevent "market disruption," to win exemptions that leave the United States 37 percent shy of the phaseout required by 2005, with at least 10,450 tons of methyl bromide exempted this year. While that is down from some 28,080 tons used in 1991, this year's total is higher than it was two years ago.That is not what the treaty envisioned, said David Doniger, senior attorney with the Natural Resources Defense Council. In the 1990s, he worked on the protocol as director of climate change for the Environmental Protection Agency."Nobody expected you would use the exemptions to cancel the final step of the phaseout or even go backward," Doniger said.U.S. officials go to a Montreal Protocol meeting in Senegal on December 7 for talks on exemptions for 2007.Bogenholm, like others in California's $1 billion organic industry, has found a non-chemical solution for her 65-acre farm overlooking the Pacific. She accepts a smaller yield and the higher costs of crop rotation and intensive plant management, but gets a price premium for pesticide-free berries.Once a conventional farmer, her epiphany came one day when she donned protective gear and locked her dog in the car so he wouldn't inhale methyl bromide leaking from a nozzle."I thought this was an insane way to make food," she said.More prevalent are farmers like Jones, who produces 10 percent of his 213 strawberry acres organically. He says he couldn't compete if he converted the rest, with three times higher weeding costs and fewer berries to show for it.Like many California growers, Jones also produces a third of his berries with alternative chemicals, but he said results are "not even close" to methyl bromide's soil purification.From Florida comes a similar complaint. "We're not totally clueless. We've seen this train coming. We've tried every alternative and put every engine on the track, but none of them run," said Reggie Brown, manager of the Florida Tomato Committee.With methyl bromide probably sticking around for several years, the EPA is re-examining its health and safety standards.California launched regulations last year to improve its strictest-in-the-nation protections for farmworkers and others.That's not enough for teacher Cheri Alderman, whose school borders a strawberry field in this coastal agricultural belt. She fears her students could inhale a dangerous whiff of the fumigant as it seeps into the air."A little dribble of poison is still poison," she said.After air monitoring detected elevated methyl bromide levels at the school four years ago, county officials say they pressed the grower. This fall he used a different chemical on the fields nearest the school.Even California's required buffer zones and ban on applying methyl bromide within 36 hours of school time don't comfort Alderman. The school draws youngsters on weekends too, and families live nearby. "It's ridiculous to think that as long as we don't do it on school days, then were OK," she said.Growers say they believe the fumigant is safe when used correctly."I'm comfortable working with the product and educating our personnel," said Jim Grainger, a fourth-generation farmer who grows 700 acres of steak tomatoes in Florida.Not so for Guillermo Ruiz and Jorge Fernandez who were used to seeing dead dogs, deer and birds in the fields treated with methyl bromide. They believe their headaches, confusion, nervousness and vision trouble stem from 10 years, ending in 2003, working in the fields removing the plastic."My eyes watered. I threw up. It gave me headaches," said Ruiz.The American Association of Pesticide Control Centers logged 395 reports of methyl bromide poisonings from 1999 to 2004. A national total remains elusive because farmworkers often do not seek medical care.Advocates for farmworkers contend in a San Francisco Superior Court lawsuit that California's exposure limits to protect neighbors are too lax. State regulators lately have emphasized stricter enforcement and tougher penalties.The size of the U.S. inventory of methyl bromide inventory is secret. The EPA refuses to disclose how much, saying the figure is confidential business information. Doniger's group says in a lawsuit against the agency that the amount exceeds 11,000 tons.Its continued use makes people such as Lynda Uvari uneasy.In her Southern California community of Ventura, people thought they had the flu a few years back. Then they noticed that their illness coincided with fumigation of a nearby field. They settled a suit with the strawberry grower.Now Uvari wonders about methyl bromide's legacy, even whether it could be linked to her son's endocrine problems."That's in the back of our minds all the time," Uvari said. "You always question."Copyright 2005 The Associated Press. All rights reserved.This material may not be published, broadcast, rewritten, or redistributed.