SF6, sulphur hexafluoride, is an inert, stable, non-toxic and non-flammable gas at atmospheric temperature. More than 10,000 tons of SF6 are produced per year, most of which (over 8,000 tons) is used as a gaseous dielectric medium in the electrical industry. Other uses include an inert gas for the casting of magnesium, and as an inert filling for insulated glazing windows. It is highly effective; however, SF6 is also a highly potent greenhouse gas. It has a global warming potential (GWP) 23,900 times greater than that of CO2 and an estimated atmospheric life of up to 3,200 years.