Health effects of the Bhopal gas leak: a review

The methyl isocyanate (MIC) gas leak from the Union Carbide plant at Bhopal, India in 1984 was the worst industrial disaster in history. Exposure estimates of gas concentrations in the area range from 85 to 0.12 ppm. Of the approximately 200,000 persons exposed, 3598 deaths have resulted as of November 1989. Chronic inflammatory damage to the eyes and lungs appears to be the main cause of morbidity. Reproductive health problems in the form of increased spontaneous abortions and psychological problems have been reported. Questions about the nature of MIC toxicity have been raised by the persistence of multi-systemic symptoms in survivors. Animal studies using radio-labeled MIC given by the inhalation route have shown that the radio-label is capable of crossing the lung membranes and being distributed to many organs of the body. This paper reviews health effects of gas exposure from published studies and discusses some of the clinical and epidemiological issues being debated.