Is industry moving into the 21st century with the perfect alternative refrigerant? That problematic topic was explored at an international conference sponsored by the National Institute of Standards and Technology (NIST) and the American Society of Heating, Refrigerating, and Air Conditioning Engineers. "Perfect" was defined in terms of the potential for ozone-depletion and direct global warming as well as system efficiency. Based on the options discussed, conference chairman Piotr Domanski concludes that "tradeoffs between different refrigerants and technologies are unavoidable. There is no perfect refrigerant, adds Domanski, who is also a group leader in NIST's Building Environment Division. The proceedings--16 technical papers--are available from ASHRAE by phone (800-527-4723), fax (404-321-5478), or by e-mail at [email protected].