According to UCC’s own Report, on the night of 2/3.12.1984, all the critical safety systems at the Bhopal plant had either been shut off or were dysfunctional:
(1) “The VGS had been removed from an operating mode to a standby mode on October 23, 1984, after the MIC unit was shut off with a total MIC inventory of 183,000 pounds [approx. 85,000 kgs.]” (p.11);
(2) “Prior to the incident, the flare tower had been removed from service for maintenance work and was not operating at the time of the incident” (p.11); and
(3) “The temperature of MIC in Tank 610 before the incident was at 15º to 20ºC as compared to the requirement of about 0ºC. The lower temperature would have retarded the reaction rates and considerably extended the time available for corrective action. The refrigeration system provided to cool the MIC in the storage tanks had been made non-operational in June, 1984.”(p.23) 
It may be noted that the refrigeration system was shut off at the peak of summer when the maximum temperature in Bhopal usually crosses 40ºC. For the next five months – till the time of the disaster – over 85 tonnes of MIC had been stored in a highly dangerous way in total contravention of the prescribed safety norms. Knowing that “bulk [MIC storage] systems must be maintained at low temperature”, to act in a manner that patently violated UCC’s own basic safety norms was absolutely criminal. It seems rather strange that for five months UCE (Hong Kong) and UCC (USA) were unaware that the most critical safety system was not in operation at the MIC unit of the Bhopal plant, a plant which was storing large amounts of extremely hazardous MIC and a plant over which they exercised managerial control.  The subsequent shutting off of the VGS and the dismantling of the flare tower only compounded the problem. Even assuming that the UCIL management had acted on their own and had not informed its regional and global headquarters about the shutting off of the safety systems, what prevented UCC (USA) from alerting its subsidiary unit in Bhopal about the warning it received on 11.09.1984 about the possibility of a “runaway reaction” in bulk MIC storage systems?
Image: Methylamine (1) reacts with phosgene (2) producing methyl isocyanate (3) which reacts with 1-naphthol (4) to yield carbaryl (5) from Wikipedia
Part 3 of a serialised article by N. D. Jayaprakash