Abstract: At approximately 2:45 a.m. on September 12, 2005, Employee #1, a chemical mill operator, was working in the chemical milling area of a facility that manufactures precision metal products. The chemical milling area of the facility refines missile fins that are manufactured to be attached to Advanced Medium Range Air-to-Air Missiles (AMRAM). During the milling process, the metal fins are placed on racks that are attached to a hoist, which lowers and raises the missile fins in and out of large vats of 40-hydrofluoric-acid (HF). The HF further refines the fins, reducing their size and producing very sharp edges. Employee #1 was removing these fins, three at time, when one of the fins slipped from his hand and struck his left leg just above his knee. This resulted in a deep cut, measuring about 4- to 5-inches long, that severed some arteries. Employee #1 was taken to Grossmont Hospital for treatment and was later transferred to Sharp Memorial Hospital, where he was hospitalized and underwent surgery to repair his knee.