Some Methyl Bromide (CH3Br) facts :
http://www.igac.noaa.gov/newsletter/19/butler.php Not all methyl bromide is anthropogenic. Most CH3Br in the atmosphere is emitted by natural processes. CH3Br, however, is the source of 50 percent of the Br reaching the stratosphere Stratospheric bromine very efficient at depleting ozone - 50 or 60 times that of chlorine on a per-atom basis. That means that at 10 parts-per-trillion, CH3Br causes the equivalent damage of any one of the major CFC's at current atmospheric levels.