Occupational exposure to hexachlorocyclopentadiene. How safe is sewage?

In March 1977, a large volume of the industrial chemical hexachlorocyclopentadiene (HCCPD) was dumped into a municipal sewage system in Kentucky. We evaluated the health effects of exposure to HCCPD in 145 sewage treatment plant workers. We found that 85 (59%) had noted eye irritation, 65 (45%) had headaches, and 39 (27%) had throat irritation. Symptoms occurred throughout the plant; however, highest attack rates occurred in primary sewage treatment areas. Medical examination of 41 employees three days after the plant was closed showed proteinuria and elevation of serum lactic dehydrogenase levels; these findings were not present three weeks later. This episode demonstrates the toxicity of HCCPD and emphasizes the vulnerability of sewage workers to chemical toxins in wastewater systems.