Abstract: ASC Process Systems is a manufacturer of autoclaves for the aerospace, composites, nuclear and glass industries. The accident occurred on 09/04/12 at approximately 10:00 a.m. The location of the accident is at the ASME Department of the main building. The victim, a 42- year old welder who was an employee of the employer was working with a coworker in the process of releasing an autoclave head cover from a locking ring. The cylinder of the hydraulic jack was positioned horizontally between two plates that were welded on the head flange and the locking ring of an autoclave head door. While applying pressure into a hydraulic jack, the head and locking ring released causing the hydraulic jack cylinder that was wedged between the two plates to inadvertently fall approximately 5 feet striking the employee's right knee. The victim was transported to West Valley Occupational Center then to Henry Mayo Hospital where he was treated and hospitalized. The causal factor of the accident was the employer did not ensure that the hydraulic cylinder was secured to minimize the hazard of it from falling and injuring employee. Equipment Information: Accident equipment Porta Power #1657 Simplex No Serial number Fell on employee Total weight Hydraulic Hand Pump and Hydraulic Cylinder= 42 pounds. Hydraulic Cylinder =22-pounds Weighed at location using employer's scale. Calibrated to CSHO weight. Tested and worked. Plates Plates used to brace were not found. Representative samples provided by employer. Photos and measurements were taken. Plate dimensions: 5-inch by 4-inch, 6-inch by 4-inch Metal Horses Six (6) - Used to support Door. Placed below door along perimeter. Largest head 4.35 tons x .7 = 3 tones, divide by 2 since there were 2 jacks in use =m 1.5 tons.