For years, electric utility transmission thermographers have wanted a camera that could spot leaking sulfur hexafluoride, SF6. As an insulating gas, SF6 is widely used by the electric power industry in high voltage circuit breakers to prevent arcing. Early efforts met with limited success through the use of imagers that required active scanning with infrared lasers. The resulting systems were somewhat cumbersome and required specific conditions which limited their utility. Now there is an IR camera that can spot SF6 in very small amounts and is a completely passive system, requiring no infrared laser but for the smallest leaks. This paper gives a brief history of SF6 as an insulating gas, problems caused by leaking SF6, the theory behind the IR camera, and why it works as well as it does. Additionally, we present some sample findings from both the laboratory and actual operating circuit breakers in high voltage systems that use SF6.