Methyl iodide had been widely seen as a replacement for another fumigant, methyl bromide, which is being phased out under international treaty because it depletes the Earth's ozone. Some growers are currently using up their supplies of methyl bromide, while others have switched to fumigants such as chloropicrin and metam sodium as alternatives.
Methyl iodide is injected into soil, kills bugs, weeds and plant diseases. It was also used by some growers of tomatoes, peppers and other crops.
Since many foreign countries look to the U.S. EPA's pesticide registry to decide their own regulations, environmentalists hope the decision means its use will be curtailed worldwide. The EPA will take comments on the decision for 30 days.