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Sulphur hexafluoride

sulphur hexafluoride

SPRI Emission Reporting Threshold
10.0 Kg/yr Pollutant Emissions to Air
This sheet is a generic summary, designed to give the reader a basic level of background information about the substance in question. Great care has been taken to represent as effectively and correctly as possible the broad range of (not necessarily consistent) information which is available from a variety of sources. The reader must accept therefore that this sheet has no legal status and cannot be relied upon in any legal proceedings. SEPA disclaims any responsibility or liability whatsoever for errors and omissions in this sheet.
What is it?
Sulphur hexafluoride is a man-made chemical. Under normal environmental conditions it is a colourless, odourless, non-toxic, non-flammable, unreactive gas. It is also very dense; about five times heavier than air, making it one of the heaviest known gases.
What is it used for?
The main uses of sulphur hexafluoride are as an electrical insulator and in the production of magnesium. It is also used to manufacture semiconductors, as an environmental tracer gas and as a filler for cushioning (such as in tennis balls or the soles of trainers).
Where does it come from?
Releases of sulphur hexafluoride occur from electrical substations, magnesium smelters and from some other consumer goods. There are no natural releases to the environment.
How might it affect the environment?
Sulphur hexafluoride is not considered likely to harm the environment in the vicinity of its release. On a global scale however, it is a greenhouse gas contributing to global warming. It has an extremely high "global warming potential" (23,000 times that of carbon dioxide), but does not contribute particularly significantly to global warming because of the small amounts released. Sulphur hexafluoride can persist in the atmosphere for up to thousands of years.
How might exposure to it affect human health?
At environmental concentrations, pure sulphur hexalfuoride is not harmful to human health. However, it is usually accompanied by impurities which may be toxic to humans.
What steps are being taken to limit the potential impacts?
The United Nations Framework Convention on Climate Change (Kyoto Protocol, 1997) introduced measures designed to achieve reduction of greenhouse gas releases (including sulphur hexafluoride). Amongst the other signaturies from around the world, the UK government (including Scotland) is committed to reaching targets reducing sulphur hexafluoride emissions by 2008-2012.