Abstract
AbstractThe chlorofluorocarbons (CFCs) have been used as refrigerants for many years. Because of their low chemical reactivity, they typically have long atmospheric residence times, and as a consequence, are distributed globally. The widespread use of these chemicals has been associated with depletion in ozone layer. Most of the nations of the world drafted and signed an agreement calling for the phaseout of CFCs. Further developments were initiated on two types of “in‐kind” replacements. The first were the hydrochlorofluorocarbons (HCFCs) and the second were the hydrofluorocarbons (HFCs). These chemicals are treated as greenhouse warming gases. It has been found that many of these chemicals are not highly toxic. The most typical responses observed following overexposure are sensitization of the myocardium to the action of adrenalin and CNS depression related to the anesthetic properties of many of these chemicals. Studies have been designed to allow for the determination of no‐observed‐effect levels (NOEL), thresholds, and EC50s as median effect concentrations. The present chapter summarizes the properties, production, uses, toxic effects, environmental impact and guidelines of exposure of these chemicals.