Abstract: At approximately 10:00 p.m. on February 8, 2002, Employee # 1, a contractor employee, was acting as a confined-space attendant monitoring an entrant who was inspecting the interior of an 85-foot-tall processing vessel at a petroleum refinery. A ventilation blower was supplying air through the lower manway, and the air stream was exiting at the upper manway, where Employee #1 was located. She was exposed to an unknown chemical that resulted in acute symptoms including vomiting, coughing, difficulty breathing, edema on her exposed skin, and loss of consciousness. Employee #1 was hospitalized for 5 days in an intensive care unit.