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13. Investigation has shown that the PVH and RWH pipe lines as well as the valves therein were of carbon steel. Besides, on account of design defect these lines also allowed back flow of the alkali solution from the VGS to travel upto the MIC tanks.
14. A very essential requirement was that the MIC tanks in the factory had to be kept under pressure of the order of 1 Kg./cm2g by using nitrogen, a gas that does not react with MIC. However, MIC in tank No. 610 was stored under nearly atmospheric pressure from 22nd October, 1984 and attempts to pressurize it on 30th November and 1st December, 1984 failed. The design of the plant ought not have allowed such a contingency to happen at all. The tank being under nearly atmospheric pressure, free passage was available for the entry of back flow of the solution from the. VGS into the tank. According to the report of Dr, Varadarajan Com-mittee, about 500 Kgs. water with contaminants could enter tank 610 through RVVH/PVH lines. The water that entered RVVH at the time of water flushing along with backed up alkali solution from the VGS already present could find its way into the tank 610 through the RVVH/PVH lines via the blow down DMV or through the SRV and RD.
(iii) The VGS that had been provided in the design was capable of neutralising Only 13 tonnes of MIC per hour and proved to be totally inadequate to neutralise the large quantities of MIC that escaped from tank. No. E 610. When the two tanks (610 and 611) themselves had been designed for storing a total of about 90 tonnes of MIC, proportionately large capacity VGS should have been furnished in the design and erected rather than VGS that was actually provided.
(iv) Due to the design defect, there was back flow of alkali solution from the VGS to the tanks which had been drained in the past by the staff of UCIL. Infact, even after the incident, such draining was done from the PVH and RVVH lines.

21. Apart from these design defects, the further lapses that were committed were :.

(a) Invariable storing MIC in the tanks which was much more than the 50% capacity of the tanks which had been prescribed,
(b) Not taking any adequate remedial action to prevent back flow of solution from VGS into the RVVH and PVH lines. This alkali solution/water, therefore used to be drained.
(c) Not maintaining the temperature of the MIC tanks at the preferred temperature of 0 degree celsius but at ambient tempera-tures which were much higher,
(d) Putting a slip blind in the PVH line and connecting the PVH line with a jumper line to the RVVH line.
(e) Not taking any immediate remedial action when tank No. E 610 did not maintain pressure from 22nd October, 1984 onwards, :(f) When the gas escaped in such large quantities, not setting out an immediate alarm to warn the public and publicise the medical treatment that had to be given immediately;"
It was also recited that if these lapses had not occurred, still the incident Would have taken place due to the basic defects in the design supplied by the UCC whose experts supervised the erection and commissioning of the plant itself. The lapses only helped to aggravate the consequences of the incident. Thereafter referring to the indications obtainable from the evidence collected during the investigation regarding the knowledge of the accused about the defective functioning of the plant the following 'pertinent recitals are found in paragraph 23 and 24 of the Chargesheet :