Abstract: At about 9:56 p.m. on July 28, 2010, Employee #1 and a coworker, regular employees of the employer, were filling six 30-gallon propane gas cylinders that were in a balloon ride basket inside an enclosed trailer, which had license number 4KL4897. Employee #1 was filling the cylinders inside the trailer, and the coworker, toward the rear end of the trailer, was helping him. As Employee #1 was filling the cylinders, a flash fire occurred from an unknown source of ignition. Employee #1 sustained second-degree flash burns on fifteen percent of his body. He required hospitalization for forty hours. The coworker did not receive any serious injury. The employer had total of four employees and was nonunionized.