WATSONVILLE, Calif. -- Strawberries are a painful subject for Guillermo Ruiz. The farm worker believes his headaches, confusion, and vision trouble stem from a decade working in the fields with methyl bromide, a pesticide that protects the berries with stunning efficiency.
Cheri Alderman, a teacher whose classroom borders a farm, fears her students could inhale a dangerous whiff of the fumigant as it drifts from the adjacent strawberry field. ''A little dribble of poison is still poison," she says.
The concerns stretch globally.
Other nations watch as the United States keeps permitting wide use of methyl bromide for tomatoes, strawberries, peppers, Christmas trees, and other crops, even though the United States signed an international treaty banning all but the most critical uses by 2005.
The chemical depletes the earth's protective ozone layer and can harm the human neurological system.
Methyl bromide's survival demonstrates the difficulty of banishing a powerful pesticide that helps deliver what both farmers and consumers want: abundant, pest-free, and affordable produce.
The Bush administration, at the urging of agriculture and manufacturing interests, is making plans to ensure that methyl bromide remains available at least through 2008 by seeking and winning treaty exemptions. Also, the administration will not commit to an end date.
The administration's ''fervent desire and goal" is to end methyl bromide's use, said Claudia McMurray, deputy assistant secretary of state.
But farmers who each year grow Florida tomatoes, California strawberries, Georgia peppers, and North Carolina Christmas trees worth billions of dollars are struggling to find a suitable replacement. Alternative organic techniques are too costly, and substitute chemicals are not as effective, growers say.
''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.
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. It wipes out plant parasites, disease, and weeds. It results in a spectacular yield.
Workers who inhale enough of the chemical can suffer convulsions, coma, and neuromuscular and cognitive problems. In rare cases, they die.
The United States signed the Montreal Protocol treaty, committing to phase out methyl bromide by 2005 as part of the effort to protect the earth's ozone layer.
A provision allows for exemptions to prevent ''market disruption." US officials are heading to a Montreal Protocol meeting in Senegal on Dec. 7 to begin negotiations on exemptions for 2007 and are preparing requests for 2008.