Are chlorine-free compounds a solution for health problems caused by ozone-depleting substances?

In January 1996, the Government of Croatia and United Nations Environment Programme (UNEP) signed an agreement on the phasing out of ozone-depleting substances in Croatia, making the problem of identifying adequate substitutes a high priority. In this paper, the main ecologic characteristics of chlorine-containing fully halogenated chlorofluorocarbons (CFCs) and partially halogenated chlorofluorocarbons (HCFCs) compared with chlorine-free hydrofluorocarbons (HFCs) are presented. The data showed HCFCs to be ecologically more acceptable than CFCs, particularly regarding the ozone-depleting potential (ODP), and have therefore been proposed as substitutes for CFCs. However, although having lower ODP, long-term they could still harm the stratospheric ozone layer, and are therefore hardly acceptable. HFCs are promising substitutes which, having no chlorine, have no ODP. Six were toxicologically evaluated; three of them were found flammable. Toxicological characteristics of three nonflammable compounds (HFC 125, HFC 134a and HFC 227ea) are presented. Their toxicity, not yet completely evaluated, appears to be low.