An employee was standing on top of a tanker truck while filling it with ethanol using a gravity-fed mechanism. As the employee was filling the ethanol through the top hatchway of the tanker truck, a flash fire occurred. The employee's shirt caught on fire and the employee jumped approximately 12 feet from the top of the tanker truck to the earthen ground below. The employee sustained burns to his torso and arms, as well as a fractured left leg.