After years of international pressure, the U.S. is finally forcing growers to cease their use of methyl bromide, an odorless and invisible chemical that has been found to be a major depleter of the earth's ozone layer. In a scramble to find a replacement for this widely-used pesticide, scientists have settled on methyl iodide. While methyl iodide does not pose the same threat to the ozone layer as methyl bromide, it is perhaps even more toxic for humans.