The supreme court today questioned the CBI for approaching it 16 years after it had diluted in September 1996 the charge of culpable homicide not amounting to murder against the accused in the Bhopal gas tragedy case.

A five-judge special bench headed by chief justice S H Kapadia raised the question on delay and asked the CBI as to why it had not filed the review petition during all these years.

Attorney general G E Vahanvati, appearing for the CBI said, "I don't know why it was not filed by the CBI but a review petition was filed in the case by someone else and it was dismissed."

He said there was a series of illegal omissions on the part of the accused from 1982 onward which led to that disaster.

"I can show series of illegal omissions from 1982 on wards that gives an impression that the disaster was bound to happen," he said.

He further said there was serious security default besides a default in the design in the plant which led to the disaster.

The bench was hearing a petition filed by the CBI seeking to recall the apex court's 14-year-old judgement that had diluted the charges against the accused who were prosecuted just for the offence of being negligent.

The petition filed by the CBI sought restoration of the stringent charge of culpable homicide not amounting to murder instead of death caused due to negligence against the accused in the case of world's worst industrial disaster that left over 15,000 people dead and thousands maimed.

The apex court had on August 31 last decided to re-examine its own judgement that led to lighter punishment of two years imprisonment for all the seven accused. The court had issued notices to all of them on CBI's plea for restoration of the stringent charge of culpable homicide.

Besides Mahindra, Vijay Gokhale, the then managing director of UCIL, Kishore Kamdar, then vice president, J N Mukund, then works manager, S P Choudhary, then production manager, K V Shetty, then plant superintendent and S I Quereshi, then production assistant were convicted and sentenced to two years' jail term by a trial court in Bhopal on June 7 last year.

The curative petition in the criminal case was filed after the trial court judgement in the 26-year-old case, following which the Centre appointed a group of ministers (GoM) to recommend steps including ways to get the punishment enhanced.