The BBC report here that special interests in a number of developed countries wish to to be allowed to continue using a bromine containing gas, methyl bromide, for various purposes such as crop fumigation. Methyl bromide is known to destroy ozone, O₃, (an allotrope of oxygen, O₂) and this is being debated at an international meeting in Canada. The Montreal Protocol does allow continued use of ozone-destroying gases for purposes agreed to be "critical", but is this really critical?