 Perfluoroalkanes do not bioaccumulate; those used in medical procedures are rapidly excreted from the body, primarily via expiration with the rate of excretion as a function of the vapour pressure; the half-life for octafluoropropane is less than 2 minutes, compared to about a week for perfluorodecalin.Low-boiling perfluoroalkanes are potent greenhouse gases, in part due to their very long atmospheric lifetime, and their use is covered by the Kyoto Protocol.The global warming potential (compared to that of carbon dioxide) of many gases can be found in the IPCC 5th assessment report, with an extract below for a few perfluoroalkanes.