Changes

A '''Class I substance''' is one of several groups of chemicals given an [[ozone-depletion potential]] (ODP) of 0.2 or higher by the [[Environmental Protection Agency]] (EPA).

A '''Class I substance''' is one of several groups of chemicals given an [[ozone-depletion potential]] (ODP) of 0.2 or higher by the [[Environmental Protection Agency]] (EPA).

Class I substances listed in the [[Clean Air Act]] include [[chlorofluorocarbon]]s, [[halons]], [[carbon tetrachloride]], and [[methyl chloroform]].  

Class I substances listed in the [[Clean Air Act]] include [[chlorofluorocarbon]]s, [[halon]]s, [[carbon tetrachloride]], and [[methyl chloroform]].  

The [[EPA]] later added HBFCs and methyl bromide to the list by regulation.  

The [[EPA]] later added HBFCs and methyl bromide to the list by regulation.