Abstract

On 9 August 1979, 62 (30.8%) of 201 workers and one of 60 management personnel in a polyvinyl chloride (PVC) fabricating plant developed acute upper and lower respiratory irritation, headache, nausea, and fainting. All were taken to hospital; none died. Sixty of the patients were women. Interviews two weeks later with 57 affected and 14 unaffected workers disclosed that illness had followed exposure to fumes from an overheated (362 degrees C) PVC extruding machine. Fumes were emitted from 1100 until 1150; cases occurred from 1100 until late afternoon. All workers who became ill worked west of the overheated extruder, and the affected manager had visited that area. The earliest cases occurred closest to the machine, and incidence decreased (from 53.3% to 15.4%) with distance westward. This pattern was consistent with plant ventilation. Incidence rates in men and women did not differ (p greater than 0.1). At two and 14 weeks, pulmonary function testing of workers with persistent pulmonary symptoms showed abnormalities in 13 of 16 and in 9 of 11 respectively; the group with persistent symptoms contained an excess of non-smokers and of those with previous respiratory illnesses. One kilogram of PVC heated to 300 degrees C releases an estimated 12.9 g of hydrochloric acid (HCl) and 4.9 g of carbon monoxide (CO). We attributed the outbreak to exposure to toxic HCl and CO and rejected the hypothesis of mass psychogenic illness.