Abstract: At approximately 12:30 p.m. on December 17, 1999, Employee #1 was working alone when he was struck on the head, shoulder, right arm, and right leg by a hydraulic cylinder used to propel the boom on a large excavator. The Vice President of D and D Equipment Rentals notified the division about the details of the incident on December 17, 1999 at 2:50 p.m. The incident was assigned to the safety engineer on December 23, 1999, and an investigation began on February 25, 2000. Employee #1 is employed full-time as a heavy equipment operator and welder and has worked for his employer for fifteen years. His employer is in the heavy equipment rental business. At the time of the incident, Employee #1 was attempting to remove two hydraulic cylinders from a Hyundai. The model number was 290-3, and the excavator equipment number was 8508. The hydraulic cylinders were located on each side of the boom, connected by a large pin running through the boom. The pin runs through the "eye" of each cylinder and is locked in place by retaining pins on each end of the pin. Employee #1 removed the retaining pins of both sides of the boom, secured one hydraulic cylinder to a small crane and attempted to slide that cylinder off the pin. Instead of sliding off the pin, the cylinder began to pull through the boom and out of the unsecured hydraulic cylinder's eye. The pin eventually pulled through the eye of the unsecured hydraulic cylinder and fell on Employee #1 causing head lacerations, a broken arm, knee injury, and a broken leg. Employee #1 was transported to Long Beach Memorial Hospital for treatment. Employee #1 was hospitalized and treated for his injuries for approximately three days. The causal factors contributing to the incident were that the employer did not follow the manufacturer's recommendations for removing hydraulic cylinders or have sufficient procedures in place to safely remove hydraulic cylinders.