Chlorofluorocarbons, more commonly known by the name Freons, a registered trademark of DuPont, are a family of compounds used as refrigerants, fire extinguishing agents, local anesthetics, aerosol propellants, blowing agents for foams, chemical intermediates, heat transfer mediums, and solvents. They are clear, colorless liquids or gases with a slight etherlike odor at high concentrations. In general, they have a low potential to cause toxicity. At high concentrations they can be acutely toxic, causing a number of adverse effects, including central nervous system depression, bronchial constriction, chest tightness, cough, difficulty breathing, pulmonary edema, dizziness, headache, confusion, incoordination, asphyxia, and cardiac sensitization. Direct dermal, ocular, or mucous membrane contact with liquid chlorofluorocarbons can cause frostbite. The chlorofluorocarbons are not associated with chronic toxicity, and are not genotoxic, reproductive or developmental toxicants, or carcinogens. Because of environmental concerns, their manufacture and use has been phased out pursuant to an international treaty. © 2014 Elsevier Inc. All rights reserved.