Abstract: On July 19, 2005, the employer, a contractor, engaged in construction grading. The employer was in the process of mass grading acreage for a new residential construction site. Employee #1, a heavy machine operator, was a full-time employee wearing shorts and a T-shirt. He was operating a Caterpillar Waterpull Grader, Model #37-30C (79P359), and grading in a straight line approximately two to three miles per hour, when the machine's steering pump pressure hose o-ring failed. A large fireball resulted when the atomized hydraulic oil was ignited by the engine heat. The fireball engulfed the cab area. Employee #1 was transported to the hospital where he was treated for flash burns to the inside of his left leg, outside of his right leg, hand to elbow on his right arm, and the right side of face. He remained hospitalized more than 24 hours.