Carbon tetrachloride was listed as a controlled substance under the Montreal Protocol by the Meeting of the Parties to the Protocol in 1990 . The Parties carefully considered the 1989 report of the Scientific Assessment Panel , which had identified carbon tetrachloride as one of the substances with a very high ozone-depleting potential : defined as the ratio of steady-state calculated ozone column changes for each unit mass of a gas emitted into the atmosphere relative to the depletion for a mass unit emission of chlorofluorocarbon-11 ( CFC11 ) .