A fuel tank safety system includes a heat exchanger in flow communication with a cabin conditioning system, a blower configured to withdraw a quantity of ullage gas from a vehicle fuel tank for routing through the heat exchanger, and conduit interconnecting the fuel tank, the blower, and the heat exchanger. The heat exchanger is configured to reduce a temperature of the ullage gas using cooling providing by the cabin conditioning system and thus reduce the fuel content (or fuel-air ratio) of the ullage below threshold required for combustion.