The decomposition products of sulfur hexafluoride (SF6): Reviews of environmental and health risk analysis

Abstract Sulfur hexafluoride (SF6) is being widely used in a variety of industrial processes, commercial products and scientific fields due to its unique characteristics such as relatively low toxicity, extreme inertness and high dielectrics. However, the chemically stable gas is one of the most potent greenhouse gases (GHGs) that cause significantly global warming, and has been, thus, blanketed into the Kyoto Protocol. From the environmental and health points of view, it is necessary to mitigate and control the emissions of the decomposition products from SF6 destruction processes because most of them (e.g. S2F10, SF4 and HF) are highly reactive, corrosive and toxic, and few of them are also potent GHGs. This article aimed to introduce the fully fluorinated gas in industrial/commercial uses, and its toxic decomposition products in their environmental and health hazards, occupational exposure limits and possible exposure sources. Because all SF6 decomposition products will be converted into fluorides in the discharged effluents and vented gases, the exposure to fluoride, being potential for causing fluorosis or chronic fluorine intoxication, and possible changes in environmental quality were also addressed in this paper. On the other hand, this manuscript also introduced another SF6 decomposition product, trifluoromethyl sulfur pentafluoride (SF5CF3), which is also a powerful greenhouse gas recently detected in the atmosphere, and reviewed its physicochemical properties and atmospheric implications.

[1]  F. Chu,et al.  SF6 Decomposition in Gas-Insulated Equipment , 1986, IEEE Transactions on Electrical Insulation.

[2]  A. Mcculloch,et al.  Fluorocarbons in the global environment: a review of the important interactions with atmospheric chemistry and physics , 2003 .

[3]  L. Christophorou,et al.  Gas phase hydrolysis of sulfur tetrafluoride: A comparison of the gaseous and liquid phase rate constants , 1985 .

[4]  J. R. Robins,et al.  Investigation of S/sub 2/F/sub 10/ production and mitigation in compressed SF/sub 6/-insulated power systems , 1993, IEEE Electrical Insulation Magazine.

[5]  Moo Been Chang,et al.  Abatement of Sulfur Hexafluoride Emissions from the Semiconductor Manufacturing Process by Atmospheric-Pressure Plasmas , 2004, Journal of the Air & Waste Management Association.

[6]  John A. Mosovsky,et al.  Sulfur Hexaflouride Tracer Gas Evaluations on Hood Exhaust Reductions , 1995 .

[7]  R. Kaiser,et al.  Mechanistic studies on the formation of trifluoromethyl sulfur pentafluoride, SF5CF3--a greenhouse gas. , 2007, Inorganic chemistry.

[8]  B. Ouyang,et al.  One potential source of the potent greenhouse gas SF5CF3: the reaction of SF6 with fluorocarbon under discharge , 2005 .

[9]  S. Buchanan,et al.  A Quantitative Look at Fluorosis, Fluoride Exposure, and Intake in Children Using a Health Risk Assessment Approach , 2004, Environmental health perspectives.

[10]  I. C. Plumb,et al.  Gas-phase reactions in plasmas of SF6 with O2 in He , 1988 .

[11]  Ole John Nielsen,et al.  Infrared spectrum and global warming potential of SF5CF3 , 2002 .

[12]  Cheng-Hsien Tsai,et al.  Decomposition of SF6 in an RF Plasma Environment , 2002, Journal of the Air & Waste Management Association.

[13]  M. Kikuchi,et al.  A rare case of paraovarian cancer coexisting with cancer of the fallopian tube: magnetic resonance appearance , 2005, Acta radiologica.

[14]  L. Paul Steele,et al.  Sulfur hexafluoride—A powerful new atmospheric tracer , 1996 .

[15]  L. Fewtrell,et al.  Fluoride in Drinking-Water , 2006 .

[16]  Carl A. M. Brenninkmeijer,et al.  Atmospheric SF6: Trends, sources and prospects , 1998 .

[17]  Charles R. McClure,et al.  Encyclopedia of occupational health and safety: Third Edition, 2 Volumes Geneva: International Labour Office, 1983, 2538 pages, $155.00. ISBN 92-2-103291-4 , 1985 .

[18]  John Aurie Dean,et al.  Lange's Handbook of Chemistry , 1978 .

[19]  Perng-Jy Tsai,et al.  Total toxicity equivalents emissions of SF6, CHF3, and CCl2F2 decomposed in a RF plasma environment. , 2006, Chemosphere.

[20]  Gábor Molnár,et al.  Study of decomposition of sulphur hexafluoride by gas chromatography/mass spectrometry , 1997 .

[21]  R. Kantamaneni,et al.  Reducing greenhouse gas emissions from magnesium die casting , 2007 .

[22]  S. Serantoni,et al.  Low-fat angiomyolipoma of the liver studied with contrast-enhanced ultrasound and multidetector computed tomography , 2006, Acta radiologica.

[23]  Paul L. Bishop,et al.  Pollution Prevention:Fundamentals and Practice , 1999 .

[24]  Hurley,et al.  A potent greenhouse gas identified in the atmosphere: SF(5)CF(3) , 2000, Science.

[25]  R. Fortmann,et al.  Dissociation of Sulfur Hexafluoride Tracer Gas in the Presence of an Indoor Combustion Source , 2001, Journal of the Air & Waste Management Association.

[26]  R. Tuckett.  Chapter 3: Trifluoromethyl Sulphur Pentafluoride, SF5CF3: Atmospheric Chemistry and Its Environmental Importance via the Greenhouse Effect , 2006 .

[27]  Clay E. Easterly,et al.  On the toxicity of sparked SF6 , 1983 .

[28]  Isidor Sauers,et al.  By-product formation in spark breakdown of SF6/O2 mixtures , 1988 .

[29]  R. A. Kennedy,et al.  A study of low energy electron attachment to trifluoromethyl sulphur pentafluoride, SF5CF3: atmospheric implications , 2001 .

[30]  J. Simons.  CHAPTER 1 – General Chemistry of Fluorine-Containing Compounds , 1964 .

[31]  C. Rinsland,et al.  Atmospheric sulfur hexafluoride: Sources, sinks and greenhouse warming , 1993 .

[32]  P. Vassiliou,et al.  Sulfur Hexafluoride (SF6): Global Environmental Effects and Toxic Byproduct Formation , 2000, Journal of the Air & Waste Management Association.

[33]  J. Casanovas,et al.  Effect of the percentage of SF6 (100%–10%–5%) on the decomposition of SF6–N2 mixtures under negative dc coronas in the presence of water vapour or oxygen , 2003 .

[34]  Malcom M. Renfew.  NIOSH Pocket guide to chemical hazards (U.S. Department of Health and Human Services- National Institute for Occupational Safety and Health) , 1991 .

[35]  F. Neuhann,et al.  Documentation of the Threshold Limit Values and Biological Exposure Indices , 2001 .

[36]  D. Desmarteau,et al.  Properties of novel fluorinated compounds and their mixtures as alternative refrigerants , 1998 .

[37]  P. Hayes,et al.  Characterisation of protective surface films formed on molten magnesium protected by air/SF6 atmospheres , 2002 .

[38]  V. L. Orkin,et al.  Scientific Assessment of Ozone Depletion: 2010 , 2003 .