Abstract: A system for drying and ventilating jet fuel tanks for reducing the fuel fume level from residual fuel in an emptied fuel tank operates in four modes. In a recirculation mode, a blower recirculates air through the tank in a closed loop. The blower suctions air from the tank and forces it through a vapor recovery unit having a cooling section with a refrigeration coil causing condensation of fuel vapor and a reheater section which reheats the air entering the tank to enhance evaporation of residual fuel. A heat recovery system circulates glycol/water mixture through a first heat recovery coil in the cooling section for absorbing heat from the air and a second heat recovery coil in the reheater section for returning the heat to the air. After fuel vapor has dried from the walls of the tanks, the system operates in a vacuum mode in which a vacuum hose, obtaining negative pressure through a pipe from the suction side of the blower, is used to remove residual puddles of fuel from the tank.