An outbreak of acute respiratory illness following a single exposure to fumes from overheated polyvinyl-chloride (9002862) (PVC) in a PVC fabricating factory was investigated. After being exposed between 1.5 and 2.5 hours to fumes emanating from an overheated extruding machine, 62 workers and 1 manager were briefly hospitalized. NIOSH investigators had 57 of the workers complete questionnaires and also administered pulmonary function tests to some of them. Subjective symptoms such as dry mouth, headache, dizziness, and dyspnea were reported by 75, 67, 63, and 48 percent of the respondent, respectively. The affected group and a comparison group were similar in age, seniority, marital status, number of dependents, and absenteeism. Both groups were generally satisfied with their jobs except for the lack of a safety program and poor air ventilation inside the factory. Nine workers still had abnormal pulmonary function 14 weeks after exposure. The investigators concludes that the outbreak of illness was probably caused by the accumulation of the PVC degradation products hydrogen-chloride (7647010) and carbon- monoxide (630080) rather than mass hysteria as was claimed by the factory management.