the results of experiments on the comparative effects of refrigerants on animal and human skin indicate that human facial skin can tolerate considerable freezing with ethyl chloride or dichlorotetrafluoroethane ( freon 114 ) but that mixtures containing large proportions of the much colder dichlorodifluoromethane ( freon 12 ) may be undesirable .
C0443384
dichlorotetrafluoroethane
C0060755
freon 114