Assessing exposure to toxic gases in Bhopal.
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Accidents, Occupational↗
Biomedical subjects
V Ramana Dhara
Publications and source records attributed to V Ramana Dhara.
Personal exposure and long-term health effects in survivors of the union carbide disaster at bhopal.
Nine years after the Bhopal methyl isocyanate disaster, we examined the effects of exposures among a cross-section of current residents and a subset of those with persistent symptoms. We estimated individual exposures by developing exposure indices based on activity, exposure duration, and distance of residence from the plant. Most people left home after the gas leak by walking and running. About 60% used some form of protection (wet cloth on face, splashing water). Mean and median values of the exposure indices showed a declining trend with increasing distance from the plant. For those subjects reporting any versus no exposure, prevalence ratios were elevated for most respiratory and nonrespiratory symptoms. We examined exposure-response relationships using exposure indices to determine which were associated with health outcomes. The index total exposure weighted for distance was associated with most respiratory symptoms, one measure of pulmonary function in the cross-sectional sample [mid-expiratory flow (FEF)(25-75), p = 0.02], and two measures of pulmonary function in the hospitalized subset [forced expiratory volume (FEV)(1), p = 0.02; FEF(25-75), p = 0.08). Indices that correlated with FEV(1) and forced vital capacity in the hospitalized subset did not correlate with the cross-sectional sample, and most indices (except total exposure) that correlated with the hospitalized subset did not correlate with the cross-sectional sample. Incorporation of distance into every index increased the number of symptoms associated; an improvement was also noted in the strength of the association for respiratory symptoms, but not for pulmonary function. The sum of duration (p = 0.02) and total exposure (p = 0.03) indices independently demonstrated stronger associations with percent predicted FEF(25-75) than the distance variable (p = 0.04). The results show that total exposure weighted for distance has met the criteria for a successful index by being associated with most respiratory symptoms as well as FEF(25-75), features of obstructive airways disease.
Adult↗
The Union Carbide disaster in Bhopal: a review of health effects.
The authors have reviewed studies of human health effects that resulted from exposure to methyl isocyanate gas that leaked from the Union Carbide plant in Bhopal, India, in 1984. The studies were conducted during both the early and late recovery periods. Major organs exposed were the eyes, respiratory tract, and skin. Although mortality was initially high, it declined over time, but remained elevated among the most severely exposed population. Studies conducted during the early recovery period focused primarily on ocular and respiratory systems. Major findings included acute irritant effects on the eyes and respiratory tract. In follow-up studies, investigators observed persistent irritant effects, including ocular lesions and respiratory impairment. Studies conducted during the late recovery period focused on various systemic health endpoints. Significant neurological, reproductive, neurobehavioral, and psychological effects were also observed. Early and late recovery period studies suffered from several clinical and epidemiological limitations, including study design, bias, and exposure classification. The authors herein recommend long-term monitoring of the affected community and use of appropriate methods of investigation that include well-designed cohort studies, case-control studies for rare conditions, characterization of personal exposure, and accident analysis to determine the possible components of the gas cloud.
Accidents, Occupational↗
What ails the Bhopal disaster investigations? (And is there a cure?).
A review of the health effects of the 1984 disaster in Bhopal, India, shows continuing morbidity of a multi-systemic nature in the exposed population. Scientific questions about epidemiologic issues are discussed with a view to understanding appropriate methods of investigation into the disaster. Other major chemical incidents were reviewed to note some of the common problems associated with public health investigations of disasters, which have included the lack of accident-related and toxicologic information, expertise, and funds. The complexity of the Bhopal crisis was underscored by the severe mortality and morbidity it entailed as well as its occurrence in a developing nation that had little experience in dealing with chemical disasters. Lessons learned from the disaster are discussed, with recommendations for disaster preparedness, long-term monitoring, rehabilitation, and treatment of the gas victims.
Accidents, Occupational↗
The Bhopal syndrome: persistent questions about acute toxicity and management of gas victims.
A review of the health effects of the 1984 gas leak from the Union Carbide plant in Bhopal, India, shows continuing morbidity of a multisystemic nature in the exposed population. Scientific debates about the causes of the accident, the spectrum of health effects, and toxicology are presented with a view to understanding the toxic substances released in the gas cloud and their roles in the causation of health effects. Clinical dilemmas, medical management, and public health issues are also discussed.
Accidents, Occupational↗
Bhopal priorities.
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Accidents, Occupational↗