Present and future environmental ''problems'' with SF6 and other fluorinated gases

Sulfur hexafluoride (SF6) is widely used as an insulating and arc interrupting gas in high-voltage systems and has found application in plasma processing of materials. However, SF6 is known to decompose in electrical discharges to form toxic and corrosive gaseous compounds such as SOF4, SOF2, SO2F2, and HF. Of particular concern are the species S2F10 and S2O2F10 that are known to be highly toxic and to be formed in corona, spark, and arc discharges in high-pressure SF6. The conditions under which these byproducts are formed, the methods for removal, and the possible hazards that they present are reviewed. Sulfur hexafluoride is also an efficient absorber of infrared radiation and is estimated to have a global warning potential that is 2.5 x 104 times greater than that of CO2. Methods that have been proposed to control the use of SF6 and reduce the rate of its release into the atmosphere will be examined. The advantages, disadvantages, and likely problems with finding technically feasible and environmentally acceptable replacements for SF6 will be discussed