Please note that the content of this book primarily consists of articles available from Wikipedia or other free sources online. Vapor (or vapour) recovery is the process of recovering the vapors of gasoline or other fuels, so that they do not escape into the atmosphere. This is often done (or required by law) at filling stations, in order to reduce noxious and potentially explosive fumes and pollution. The negative pressure created in the (underground) tank by the withdrawal is usually used to pull in the vapors. They are drawn-in through holes in the side of the nozzle and travel through special hoses which have a return path.