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The Accelerated Phaseout of Class I Ozone-Depleting Substances

Sections 601-607 of the Clean Air Act

In July 1992, EPA issued a final rule (57 FR 33754) implementing section 604 of the Clean Air Act Amendments of 1990. That section limits the production and consumption of a set of chemicals known to deplete the stratospheric ozone layer. EPA controls production and consumption by issuing allowances or permits that are expended in the production and importation of these chemicals. These allowances can be traded.

The July 1992 rule required producers of class I substances (chlorofluorocarbons (CFCs), halons, carbon tetrachloride, and methyl chloroform) to gradually reduce their production of these chemicals and to phase them out completely as of January 1, 2000 (2002 for methyl chloroform). In addition to these production limits, the rule required a similar reduction in consumption, defined as production plus imports minus exports. Please note that the term 'consumption', as it applies to the phaseout regulation, is a defined term, and does not refer to the 'use' of a controlled substance.

On February 11, 1992, the United States, responding to recent scientific findings, announced that the phaseout of the production of CFCs, halons, carbon tetrachloride, and methyl chloroform would be accelerated and that these substances would be phased out by December 31, 1995. It was also stated that the U.S. would consider recent evidence which suggested the possible need to phase out methyl bromide. At the same time, the Agency received petitions from environmental and industry groups to accelerate the phaseout of these chemicals.

At the fourth meeting of the Parties to the Montreal Protocol, which took place in Copenhagen in November, 1992, the Parties made a number of decisions which were reflected in rule accelerating the phaseout (58 FR 65018). This regulation implemented the United States' obligation to the agreements made by the Parties in Copenhagen, and implemented the accelerated phaseout of ozone-depleting substances, while responding to the petitions received by the Agency from environmental and industry groups.

The Parties to the Protocol agreed to accelerate the phaseout of CFCs, carbon tetrachloride, and methyl chloroform to the end of 1995 and halons to the end of 1993. In addition, the Parties agreed to add hydrobromofluorocarbons (HBFCs) to the class I list and phase them out by the end of 1995. In accordance with these agreements, the regulation scheduled the phaseout of these chemicals by these dates. Benefits of these agreements can be found here.

The United Nations Environmental Program (UNEP) Scientific Assessment identified methyl bromide, widely used as a soil fumigant, as a significant ozone-depleting compound. In 1992, when listing methyl bromide as a controlled substance under the Protocol, the parties set an ozone depletion potential of 0.7. In 1995, based on updated science, the parties adjusted the ozone depleting potential to 0.6. Starting in 1994, the regulation froze the production and consumption of this chemical at 1991 levels.

In accordance with revisions made to the Clean Air Act in 1998, the U.S. conformed its phaseout of methyl bromide to the Protocol phaseout in the June 1, 1999, and November 28, 2000, final rulemakings. Starting in 1999, the production and import of methyl bromide was set to 75% of the 1991 baseline. In 2001, production and import were further reduced to 50% of the 1991 baseline. In 2003, allowable production and import was reduced again, to 30% of the baseline, leading ultimately to a complete phaseout of production and import in 2005. Beyond 2005, continued production and import of methyl bromide is allowed only for limited critical, emergency, and quarantine & preshipment uses.

In addition to the above phaseout schedule, the phaseout program has implemented a number of additional changes over the years:

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