Present and future environmental "problems" with SF/sub 6/ and other fluorinated gases

Summary form only given. Sulfur hexafluoride (SF/sub 6/) is widely used as an insulating and arc interrupting gas in high-voltage systems and has found application in plasma processing of materials. Because it is nontoxic, chemically inert, and thermally stable at temperatures up to 500/spl deg/C, SF/sub 6/ has been considered to be an environmentally safe and acceptable gas for most applications. However, SF/sub 6/ is known to decompose in electrical discharges to form toxic and corrosive gaseous compounds such as SOF/sub 4/, SOF/sub 2/, SO/sub 2/F/sub 2/, and HF. These products are generated under a wide range of conditions in both low-pressure and high-pressure discharges. Of particular concern are the species S/sub 2/F/sub 10/ and S/sub 2/O/sub 2/F/sub 10/ that are known to be highly toxic and to be formed in corona, spark, and arc discharges in high-pressure SF/sub 6/. 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 warming potential that is 2.5/spl times/10/sup 4/ times greater than that of CO/sub 2/.