The National Highway Traffic Safety Administration reports that 10% of fuel truck fires caused 10% of truck accident fatalities in 2012. Considering how rare fuel truck fires are, that is a high number.
Part of the reason why so many fatalities happen with fuel tank fires is because of the nature of truck fuel. A semi can have up to 100 gallons of fuel, so if that ignites there is enough fuel for a huge fire or explosion. Secondly, fuel tank design on trucks means that the tank is placed outside the truck, under the driver’s cab. In the event of an explosion or fire, the passenger and driver are greatly endangered. Finally, experts have stated that the walls of the tank themselves are too thin and are not reinforced. In a serious collision, the fuel tank can puncture, creating a danger of fires and explosions.