The most commonly-known f-gases are the early, so-called first generation F-gases: the CFCs that destroyed the ozone layer and were banned by the Montreal Protocol. However, in the race to save the ozone layer, the use of their second generation cousins was accelerated: HCFCs, now also banned under the Montreal Protocol. The focus in this report is on the third generation of f-gases: HFCs are powerful greenhouse gases developed by the chemical industry to solve the ozone crisis, but if used as substitutes for all the ozone-destroying chemicals they were designed to replace, could also end up in the atmosphere and have a devastating impact on the climate.