The report gives results of a project to provide a scientific basis for choosing a reasonable standard of purity for recycled chlorofluorocarbon (CFC) refrigerant in operating automobile air conditioners. The quality of refrigerant from air conditioners in automobiles of different makes, ages, and mileages, from different parts of the U.S., and with both failed and properly working air conditioners was measured. The refrigerant (CFC-12) was tested for water content, acidity, residue (compressor oil) quantity, refrigerant purity, inorganic chloride, and inorganic fluoride. Of the 227 cars sampled, neither the refrigerant nor the residue showed measurable levels of acid or inorganic chlorides and fluorides. The gaseous refrigerant, in all but two samples, was of higher purity than the specification for new CFC-12. The residue was greater than 99% pure in all but two samples. The mean water content for all samples (56 ppm) exceeded the Federal Specification BB-F-1421A of 10 ppm maximum. The work will be the basis for programs to reduce CFC emissions from the servicing of automotive air conditioners.