Bhopal methyl isocyanate affected population and cancer susceptibility: where do we stand now?

Further to our recent publications on cancer morbidity of Methyl isocyanate (MIC) exposed long-term survivors and their offspring and carcinogenesis of MIC in this journal (Senthilkumar et al., 2011; 2012), my attention was drawn to express my views to Indian Council of Medical Research (ICMR) for the need to validate MIC in cancer etiology, in particular, to cancer risk prediction in the present and future generations of the affected population. Since its occurrence, Bhopal MIC gas tragedy remains controversial and ambiguous. Uncontrolled release of MIC from the Union Carbide pesticide manufacturing plant in Bhopal, India on 3rd December, 1984 resulted in mortality of 3600 individuals and an estimated 2,00,000 was lethally exposed (Dhara and Kriebel, 1993). This infamous smog episode induced health effects in Bhopal population has received immediate attention of the medical community. In 1985 a governmental organization, ICMR launched a series of long-term medical studies focused on immune system functioning, ocular, respiratory, reproductive, psychological, neurobehavioral and genetic effects. ICMR followed-up MIC exposed population for 10 years till 1994. After completion of this first phase study ICMR finally declared that the effects of MIC are short-term and never persist in affected population (ICMR, 2004). However, ICMR findings were criticized by scientific experts due to self-selected sample, the lack of complete evidence regarding health effects of the exposure, and many other limitations also led to the controversy. Further to these findings, no biomonitoring strategies or followup protocols implemented by any scientific community to assess the long-term risk in MIC affected population. While there is an uncertainty and debate since 1994 regarding the long-term health effects in the MIC affected population. Increased cancer morbidity (Senthilkumar et al, 2011), genetic instability (Malla et al., 2011), pregnancy loss and delayed development in male progenies (Sarangi et al., 2010) were recently reported exposure-effects in the MIC affected population after 27 years. In the wake of the controversies, ICMR is now researching for the neglected toxic evidence again after 17 years. ICMR launching a second phase study in MIC affected population of Bhopal. Being a researcher, I am striving to contribute to this issue for past six years investigating cancer epidemiology, immune status and cytogenetic effects in MIC affected population through biomonitoring, with the funding granted from Council LETTER to the EDITOR