Abstract: Employee #1 was a maintenance technician at LG Epitaxy, Inc., a company that performs epitaxial processes for semiconductor manufacturing. He reported to work in the fabrication area and was briefed by a coworker, also a maintenance technician, about the day's projects. After a few minutes, other workers began to smell a strong chemical odor, and some saw a yellow or red cloud. They quickly evacuated the area. The coworker who had briefed Employee #1 investigated the source of the odor, which seemed to be near the acid sink in the fabrication area. He found Employee #1 standing under an emergency shower, surrounded by a yellow atmosphere. The coworker yelled for Employee #1 to leave the area and guided him to an emergency shower outside, at the rear of the building. Employee #1 had burns on his legs, arms, and face; he received first aid from the fire department before being taken to the hospital. He developed pulmonary edema in the hospital, and died 15 days later of multiple organ failure. Employee #1 was working a weekend shift, with relatively few other people, and there were no witnesses to the accident. Subsequent investigation revealed empty containers of isopropyl alcohol and nitric acid around the acid sink and adjacent bell jar area. It seems that Employee #1 mistakenly added the alcohol to a reservoir at the bell jar area that already contained a mixture of nitric and hydrofluoric acids. Normally, only two acids are added to the reservoirs. Adding the isopropyl alcohol resulted in a chemical reaction that not only sprayed Employee #1 but also released nitric oxide and nitrogen dioxide gases, both of which he inhaled. Employee #1 was not wearing any personal protective equipment at the time of the accident.