Abstract: On Jun 9, 2011, three employees, of American Asphalt Repair and Resurfacing Company Inc., were paving the parking lot and the loading docks in South San Francisco, CA. Employee #1 and Employee #2 were operating as crews on a Gilchrest proparc Model Number 813 Serial Number 2-3251 from the operator's station paving the asphalt. At approximately 2:30 to 3:00 p.m. Employee # 1 observed a hydraulic fluid leak beneath the Gilchrest Proparc he was operating. All of a sudden, there was a loud explosion followed by a fireball four feet high coming from the source of the hydraulic fluid leak. Employee #1, the operator in control at the time of the explosion, engaged the forward control lever and jump out of the machine he was operating. The Gilchrest proparc was not turned off and it ran on its own without an operator for approximately six feet. Employee # 3 was pinned between the vehicle and the wall of a loading dock near a protruding uncaps rebar five inches long on the side of the loading dock. Employee #1 did not realize that Employee #3 was pinned by the Gilchrest proparc to the loading dock until he heard him screamed with pain. Employee #1 backed up the Gilchrest proparc in order to release the pinned employee from the situation. Employee #1 and Employee # 2 state that they did not know that Employee #3 was positioned at the right front of the operating Gilchrest prop aver. Employee# 3 was shoveling asphalt from a drain and stated that was typically his duties. Employee #1 and Employee #2 did not observed Employee#3 working in front of the vehicle before the explosion and fireball. The employer failed ensure that the vehicle operators knew of the presence of other workers on foot in the areas of their operations.