Tetrafluoroethane molecule, computer model. This molecule is an inert gas at room temperature. Tetrafluoroethane has been used as a refrigerant and propellant since the early 1990s. However, when released into the atmosphere it acts to deplete the ozone layer and contribute to climate change. It will be banned for use in vehicle air conditioning units in th EU from 2011. Atoms are represented as rods and are colour-coded: carbon (grey), fluorine (green) and hydrogen (white).