Methyl bromide is classed as an ozone-depleting substance because it damages the stratospheric layer that protects people, plants and animals from solar radiation, which can produce skin cancer and eye cataracts. The gas is believed to be responsible for ten percent of damage to the ozone layer and is also a greenhouse gas. Methyl bromide is a halon gas used as fumigant, sterilizing soil and killing pests on fruit and vegetables in storage. Exporters of agricultural produce, especially in the Third World, depend heavily on methyl bromide for cheap pest control.
The Parties to the Montreal Protocol, who met in Beijing, China, from 29 November to 3 December 1999, agreed to take the first steps in closing the loophole to end unlimited use of the agricultural fumigant methyl bromide. No economic substitute has yet been found and a meeting of the Montreal Protocol in 1992 decreed to freeze its use indefinitely at 1991 levels by 1995 instead of banning it altogether by the year 2000, as had been done with other commercially-used ozone-depleting gases. Countries agreed in 1997 to allow exceptions to the ban for "critical uses" up to 2005. However, in March 2004 the world community agreed to permit the United States and 10 other northern countries to continue using the pesticide for a further year because of continuing failure to agree on what exemptions should be granted. The northern countries will be allowed to use an amount equal to more than 50 percent of all the methyl bromide consumed by 34 developed nations in 2001, and nearly three-quarters of that used by developing nations the same year. The push for exemption was led by the United States, whose request accounted for two-thirds of the total. According to EU officials, technically and economically feasible alternatives to methyl bromide could come on- stream after 12 months.