Abstract: Employee #1 was working in as a plastic parts fabricator in building 636, room T122, the silicon room. In this room metal pots were filled with a plastic material which then was processed and spread onto metal tables to form pliable plastic sheets. The pots weigh about 22 lb empty and 40 to 55 lb full. The thickness of the sheets is adjusted by loosening Allen head screws along the side of the table and raising or lowering the side rails. Employee #1 was loosening Allen head bolts with a T-handle Allen wrench. One bolt was seized in place and as it broke loose Employee #1 felt a pain in his right arm and shoulder. Employee #1 continued to work and about 15 minutes later he tried to lift a 22-lb metal pot when he felt severe pain in his shoulder. He was diagnosed with a torn rotator cuff and underwent surgery two months later.