Hydrochlorofluorocarbons

CFCs and HCFCs have contributed to our quality of life, particularly as valuable components in refrigeration and computer technology. However, their impact on the atmosphere has prompted several countries to agree to stop producing them. The Montreal Protocol on Substances that Deplete the Ozone Layer was signed by 43 countries in 1987 to limit and eventually eliminate the production and use of CFCs. When additional evidence emerged that the ozone layer was being damaged more quickly than originally thought, more than 90 countries signed an amendment to the Montreal Protocol in 1990. In the year 2000, CFCs were banned from use, and guidelines included new phaseouts for HCFCs and HFCs by the year 2020 if possible, and no later than 2040.

Other research is increasing the need to develop acceptable alternatives to HCFCs. In laboratory tests, male rats exposed to 5,000 parts per million (ppm) of HCFCs over a two-year period (equivalent to what humans working occupationally with the compound might experience over 30-40 years) developed tumors in the pancreas and testes. The tumors were benign and did not result in death for the tested rats. Nevertheless, this research resulted in the recommended eight-hour occupational exposure levels to HCFCs for humans being reduced from 100 ppm to 10 ppm.

Two possible alternatives to HCFCs are already being used successfully. Refrigerators that use propane gas, ammonia, or water as coolants are being tested in research laboratories, and are using up to 10% less energy than typical models using CFCs as a coolant. Telephone companies are experimenting with crushed orange peels and other materials to clean computer circuit boards, as substitutes for another important use of CFCs and HCFCs. Certain microorganisms are also being tested that degrade HCFCs and HFCs, which could help in controlling emissions of these compounds during manufacturing processes involving their use.