Industrial overexposure to chlordecone, an organochlorine insecticide, caused tremor in 76 of 148 exposed workers. Chlordecone was absorbed through oral, respiratory, and dermal routes, the last possibly the most significant. Epidemiology of this incident disclosed low-level, wide spread environmental exposure of man to chlordecone. In 23 workers with chronic chlordecone intoxication, tremor was associated with opsoclonus, pleuritic pain and arthralgia. No seizures were reported. The site of action of chlordecone on the central nervous system is unknown. It concentrates inhuman adipose and hepatic tissue but is not biodegradable, either in humans or elsewhere in nature.