In utero exposure to methyl isocyanate in the Bhopal gas disaster: evidence of persisting hyperactivation of immune system two decades later

The investigators were aware of the fact that it is extremely crucial to select subjects very carefully to avoid false-positive results. Since 24 years have elapsed following the exposure, a very careful and deliberate attempt was made to identify and recruit subjects to ensure that they were indeed exposed to MIC in utero. A cohort was established following extensive verification of the birth records of subjects exposed in utero and after ascertaining the following criteria of the pregnant mothers: physical presence and address of stay on the night of the MIC leak; distance from the factory; protective measures taken at the time of the gas leak, if any; remained outdoors or indoors; if outdoors, the activity profile, that is, running or exertion or walking or driving etc; and symptomatic profile such as respiratory, cutaneous and ocular symptoms on exposure on that night to corroborate exposure.