So this is what Bush and company mean when they talk about unleashing economic freedom: The United States plans to seek a waiver in international talks this week that would allow American farmers to continue using methyl bromide, a pesticide slated to be banned in 2005 because it contributes to destruction of Earth's protective ozone layer. The pesticide, which has also been linked to prostate cancer in farm workers and neurological problems in people exposed to large quantities, was scheduled to be phased out in 2005 under the Montreal Protocol, the 1987 treaty struck under the Reagan administration to restrict the use of ozone-destroying chemicals. The pact, which has been updated several times and signed by more than 160 nations, is widely considered the most successful international environmental treaty in history.