The article discusses 1,1,2,2,3-pentafluoropropane (R-245ca) as a potential far-term alternative for R-11. Although 1,1-dichloro-2,2,2-trifluoroethane (R-123) is generally recognized as the leading alternative refrigerant for near-term use to replace R-11 and is being adopted by chiller manufacturers for use in new equipment and (to some extent) by users to retrofit existing equipment, due to its chlorine content and consequent potential to deplete stratospheric ozone, it is subject to future production phaseout and therefore is viewed as a transitional alternative. Because several years are normally required to thoroughly evaluate any new candidate alternative for toxicity, environmental acceptability, end-use applicability, production viability, and cost, and to bring the new chemical to market, EPA/AEERL initiated a project in 1988 to investigate an array of new potential alternative chemicals. This effort recently has revealed several promising new candidate refrigerants, including the one discussed in the article.