...tance. Because of its ozone depleting characteristics, the use of methyl bromide was gradually phased out under the Montreal Protocol between 1998 and 2005. A complete ban is in force as of 1st January 2005. Some exemptions apply: (i) less developed nations can delay phase out to 1st January 2015 and (ii) âcritical usesâ, for which no suitable alternatives exist, can continue to use methyl bro ...