The Montreal Protocol began in 1987 as a gathering of countries to identify ozone-depleting substances, becoming the first international environmental treaty with such worldwide participation.
The gaseous ozone layer is found in the stratosphere, the second layer of atmosphere located approximately 10 to 50 kilometers from the earth. The thin ozone layer shields the earth from harmful ultraviolet light that can cause skin cancer and eye damage in humans and gradual changes in plant and animal life.
In September 2000, scientists reported that the ozone layer hole, located above Antarctica and Argentina, was at its largest — 1.5 times the size of the U.S. The ozone layer can heal itself over time, scientists say, but it could take up to 50 years.
In 1991, more than 160 countries signed an amendment to the Protocol, the Copenhagen Agreement, which listed several ozone-depleting substances that were to be phased out, including methyl bromide.
According to the U.S. Environmental Protection Agency, human-made methyl bromide has contributed to about 4% of total ozone depletion over the past 20 years. Of this, about 2.5% of ozone depletion can be attributed to agricultural fumigations. The continued use of methyl bromide as an agricultural pesticide may contribute 5% to 15% of future ozone depletion if it is not phased out, the EPA said.
Under the Montreal Protocol's phase-out plan, production was capped at 1991 levels beginning in 1994. From that 1991 baseline production level, developed countries were scheduled to reduce production by 25% in 1999, 50% in 2001, 70% in 2003 and 100% in 2005.
For developing countries, consumption will be frozen in 2002 at 1995-98 average levels, followed by a 20% reduction in 2005 and complete phase out in 2015. However, critical emergency uses and quarantine and pre-shipment uses are exempt from these controls.
Many countries are accelerating national phase-out plans. A complete or near complete phase out currently exists in Denmark, The Netherlands, Germany, Slovakia, Estonia, Sweden, Norway and Georgia. Developing nations also are embracing the phase out, said David Mueller, a U.S. fumigation expert who works with developing nations to help meet the international standards.
In the United States, the EPA supports the phase-out of methyl bromide, but the ban has been met with resistance by the North American Millers Association, Washington.
NAMA is not convinced that banning methyl bromide will benefit the repair of the ozone layer, according to James Bair, vice-president. "It is not universally held that banning methyl bromide is going to improve the environment," said Bair, noting scientific presentations at the 2000 annual meeting of the parties to the Montreal Protocol that shed doubt on earlier findings of methyl bromide's damage to the ozone.
The EPA emphasizes the importance of world compliance with the Montreal Protocol. The agency has said that delays in ending production could result in additional damage and prolong the ozone layer's recovery.