It kills everything it comes into contact with. It destroys the Earth's ozone layer. But Florida tomato farmers inject more than 5 million pounds of it into the ground every year.
It is methyl bromide, an odorless gas used since the 1950s as a soil fumigant to kill weeds, fungi and pests. Farmworkers' advocates, environmentalists and scientists say the harm from the biocide outweighs its benefit. In 1993 Congress amended the U.S. Clean Air Act to phase out methyl bromide by 2001.
But last month the act was quietly changed to push the ban back until 2005. Farmers want to delay it even further. The tug of war -- with policy and profit pulling against science -- was on display when scientists and lobbyists met in Orlando this month for an annual conference on methyl bromide alternatives.
The biggest threat from methyl bromide comes from its eventual home in the stratosphere. Farmers say most of the gas breaks down in the soil; in contrast, the EPA says 50 to 95 percent escapes into the atmosphere, where, EPA testers say, the methyl bromide molecule destroys ozone 50 times more effectively than chlorine does.
Less ozone in the atmosphere means more skin cancer and cataracts. And in October, the World Meteorological Organization and the U.S. National Oceanic and Atmospheric Administration reported that the ozone hole over the Antarctic is now bigger than ever -- covering an area larger than North America.
When talking about methyl bromide, Richard Herrett, director of the nonprofit Agricultural Research Institute, a Washington-based organization heavily influenced by farmers and chemical companies, concentrates on the big picture. "By the year 2050," he says, "we will need to increase food production 300 percent."
Herrett links the small-picture issue to the global outlook: "I'm concerned that if we go in the direction of losing methyl bromide and, as a consequence, lose our agricultural capabilities," nothing less than world hunger may result.
"The other part that I'm concerned about is that people believe that there are alternatives to methyl bromide," Herrett continues. "I am unaware of any single alternative right now, and a combination of two or three strategies are certainly going to be more costly to the producer."
Surrounding Herrett at the conference are bulletin boards with the promising findings of scientists searching for that alternative. The reports study other chemicals or examine treating soil with heat, hot water and even irradiation.
"We kill everything," says Frank Davis of Bioterm, a start-up company that makes a machine that microwaves the soil. Actually, his company would like to make these machines; right now he's seeking investors.
A solution could mean big money for its inventor. Methyl bromide is a $400 million business in the U.S. alone, mostly used on strawberries in California and tomatoes in several states.
To use methyl bromide, the farmer typically clears the field and injects the gas about 6 inches below the surface. The field is covered with plastic sheeting overnight to hold in the gas as it does its work. With tomatoes, the tarp is left on for the whole two- to four-month growing season. About 94 percent of Florida tomato lands -- about 37,600 acres -- are treated in this manner. Florida's tomato crop accounts for about 11 percent of the yearly U.S. methyl bromide consumption.
Careless handling of methyl bromide causes eye and skin irritation, damage to the central nervous system and kidney problems. It has been blamed for sick schoolchildren downwind of fumigated fields, as well as for health problems and 19 deaths among farmworkers.
Environmental and labor groups began to push for a ban on the chemical in the late 1980s. After the U.S. agreed to a 2001 phase-out, those groups turned their attention to the international treaty. In 1997 a worldwide ban was set for 2005, with the exception of some Third World nations, which were allowed to use the fumigant in small amounts through 2015. That put American farms groups on the offensive. The U.S. accounts for 40 percent of global methyl bromide use. Why, they wondered, should they have to stop using it first?
"I'm as concerned as anyone about the ozone and the protection of the ozone layer," Herrett says. "But I believe that anthropogenic `man-made` bromide -- and the evidence that it is causing a loss of the ozone layer -- is at best weak."
So far, Herrett's side is winning. Rep. Vic Fazio, a California Democrat, attached a rider to this year's budget bill that pushes back the phase-out to 2005 and opens what environmentalists say is a loophole that allows methyl bromide to be used after 2005 for as-yet-undefined "critical uses." By enacting this legislation, Fazio has bought some time for bromide-dependent farmers and the two major U.S. producers of the gas.
But they want more, and they may get their wish. Rep. Dan Miller (R-Bradenton) has sponsored a bill to push the U.S. ban back to 2015.
Peter Sparber, spokesman for the Methyl Bromide Working Group, said Fazio's rider "fails to resolve the serious problems agriculture and trade will face if methyl bromide is banned."
In the meantime, the other serious problems -- those of health and environment -- are in the hands of scientists and entrepreneurial inventors.