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

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.

Under the spark condition, the final toxic products of SF6 decomposition in the presence of water vapor have been proposed in the literature to be hydrogen fluoride (HF) and sulfur dioxide (SO2) or sulfuric acid (H2SO4). Figure optionsDownload as PowerPoint slide