Negligence could have caused Koyli blast, says forensic team

Primary observations and investigations by a team of Forensic Science Laboratory officials at the blast site of Indian Oil Corporation's Gujarat Refinery point to human negligence as the possible cause of the explosion that ripped through the fluid catalytic cracking unit (FCCU) last week.

A Forensic Science Laboratory (FSL) team, headed by M S Dahiya on Monday evening, submitted its primary report on the explosion in the cracking unit of the refinery, to Sudhir Sinha, Commissioner of Police, Vadodara.

Speaking on condition of anonymity, one FSL team member said: "We have noticed that the tank of the slurry settler of FCCU was blown away and has damaged the reactor as well as the other divisions of the unit. The upper half of tank was blown away to a distance, while the lower portion collapsed to the ground. We have concluded that an air bubble might have formed inside the tank, which resulted in the blast," said the team member.

He added that the air bubble formed in the tank might have reacted with the hydrocarbons in the tank at a temperature of about 230 degree, causing the explosion. Chances of a blast in slurry settler are almost nil under normal circumstances.

The tank of the slurry settler contains crude oil and alumina based fluidised catalysts. The FSL team has given its clearance to IOC for dismantling the damaged structure of FCCU.

Before the blast, the craking unit was shut for maintenance for about 18 days. "We think that the tank was not properly cleared before resuming operations,' the FSL official said.

The FSL team has also collected pieces of metal for testing purpose found after the explosion. The FSL officers denied to have come across any evidence of sabotage in FCCU and said that human negligence appeared to be the most probable cause of the mishap.

However, FSL officers denied to put an estimate to the monetary losses. "The plant has suffered huge damage. It is difficult to estimate the loss in terms of value at primary stage," said an FSL officer.

At present a number of teams are working at the blast site to ascertain the cause behind the blast in slurry settler. The teams from Universal Oil Products (UOP) who commissioned FCCU, Engineering India Ltd (EIL) and senior officials of IOC are working at FCCU site for last three days.