Hydrochlorofluorocarbons (HCFCs) are a class of chemical compounds that deplete the stratospheric ozone layer, leading to overexposure to ultraviolet (UV) radiation at the earths surface. Excessive UV radiation damages biological systems and causes malignant melanoma and other skin cancers, cataracts, and harm to certain crops and marine organisms. Reversing the course of stratospheric ozone depletion is crucial to human and environmental health worldwide. As a Party to the Montreal Protocol, the United States is subject to a cap on the consumption of HCFCsdefined as production1 plus imports minus exportsin an international effort to protect the stratospheric ozone layer (UNEP 2000). Specifically, the United States is obligated to phase out production and consumption of HCFCs by 2030 by making graduated reductions in HCFC consumption by certain dates. In order to meet these interim reduction targets, the U.S. Environmental Protection Agency (EPA) established a schedule for the phaseout of HCFCs starting with those with the highest ozone depletion potentials (ODPs), namely HCFC-141b, HCFC-142b, and HCFC-22.2 Consumption of HCFC-141b was phased out in 2003. The next phaseout milestone occurs on January 1, 2010, when the production and import of HCFC-142b and HCFC-22 (unless for use in equipment manufactured prior to January 1, 2010) will cease. Under the restrictions, between 2010 and 2020, both the production and import of HCFC-142b and HCFC-22 will still be permitted to service existing equipment. In the United States and worldwide, the primary use of HCFC-22 is as a refrigerant, whereas the primary use of HCFC-142b is as a blowing agent in the foam industry (UNEP 2003a). While HCFC-142b is also blended with other constituents to form refrigerant blends, its use in the U.S. air-conditioning (AC) and refrigeration industry is minimal, and therefore servicing demand for R-142b3 is not presented in this analysis. However, a brief section discussing the basic needs for HCFC-142b and other HCFCs is provided. Estimated consumption of R-22 in the U.S. air-conditioning (AC) and refrigeration industry currently totals approximately 110,000 metric tons in 2007 and is by far the largest use of an HCFC by any U.S. industry (EPA 2007a). For this reason, and because the allowable servicing of existing equipment between 2010 and 2020 is applicable primarily to the AC and refrigeration industry, this report presents estimates of the projected quantity of R-22 needed to service AC and refrigeration equipment and the anticipated installed base of such equipment beyond 2010. In quantifying future servicing needs and evaluating how these needs can be met, the objective of this analysis is to provide a resource to assist in the allocation of future production and consumption allowances.