Vizag gas leak case much more than human negligence: Experts

How did the gas leakage mishap at a private factory in Andhra Pradesh’s Visakhapatnam happen last month? It was due to human negligence and security lapses, an expert committee, appointed by the National Green Tribunal (NGT), has concluded.

However, a section of independent scientists and experts have accused the committee of being “too soft” on the management of LG Polymers plant, where the leakage of Styrene vapour occurred, and called for more stringent action against the firm.

The five-member committee, headed by retired judge B Seshasayana Reddy, was constituted to probe the circumstances that led to the accident at the chemicals factory in the coastal city on May 7, claiming 12 lives and injuring over 500 others.

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In a 155-page report submitted to the NGT, the committee listed out technical and security lapses responsible for the accident on the day when the plant was reopened after a six-week lockdown.

However, some industry experts and scientists have questioned the “integrity and scientific quality” of the inquiry report. “It is a mere compilation of information given by the company,” said Dr K Babu Rao, a former scientist of the Indian Institute of Chemical Technology (IICT) and a member of “Scientists for People”, an NGO.

Disaster waiting to happen

Reminiscent of the 1984 Bhopal tragedy, a gas leak from the polymer plant was a disaster waiting to happen. It has emerged that serious lapses in safety protocols and flouting of environmental norms had led to the tragedy.

The South Korean-owned LG Polymers makes polystyrene and co-polymers by using styrene, a flammable liquid gas, as raw material. The plant is located near Gopalapatnam, about 15 km far from Visakhapatnam.

“The root cause for the mishap was lack of experience of LG Polymers in monitoring and maintaining full tanks of styrene that were left idle for several weeks. The plant failed to assess the situation by trained manpower,” the NGT-appointed committee said.

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Following the exothermic reaction, the styrene started auto polymerising and led to rapid reaction and heating. As the temperature rose, styrene started vapourising. Following an increase in pressure in the tank, five safety valves on the M6 tank rooftop opened and started emitting vapour, the report pointed out.

“The emission started at 2:42 am. No alarm generated when vapour leakage occurred and auto sensor of styrene failed to detect it. The impact could have been reduced if the chillers servicing M6 tank were running at that time. But the chillers were switched off the previous evening as per routine practice as it requires little or no chilling at night,” the panel said.

The M6 storage tank, containing 1,830 tonnes of styrene, developed a leak and styrene vapours spread towards the west side due to wind direction and affected the people in the nearby residential colonies, it said.

The committee recommended the constitution of district crisis group, led by the Collector, to prevent recurrence of such incidents. The group should meet once in every 45 days to review the safety and hazards of the industries located in the region, it said.

Technical lapses

There was insufficient Tertiary Butyl Catechol (TBC) used as an inhibitor chemical in the Styrene tank to control its temperature, the panel said. TBC is ineffective above 52 degrees Celsius. Stored in liquid form under 20 degrees Celsius, Styrene evaporates with rise in temperature in a process called auto-polymerisation. Retarders and inhibitors are used to slow down any runaway chemical reaction.

The tank had no provision of monitoring temperatures at top layers of the storage. Also, there was no onsite emergency plan, it said.

The committee recommended that the plant’s managing director, safety officer and production department should be held accountable for lapses, along with the departments of industries, factories and boilers that conducted periodic inspections.

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The M6 tank was an old one and did not have temperature sensors at the middle and top. There was one sensor at the bottom of the tank where refrigeration was provided. Due to this, the building-up of temperature at the top of the tank was not noticed. “This shows the clear-cut negligence on part of the factory,’’ the report said.

“There was no interlocking system arrangement between the temperature and refrigeration system,” the report said, adding that had such a system been in place, the rise in temperature would have started the refrigeration.

The public siren was not sounded because it was a manual system, located at a place which had become inaccessible due to the vapour cloud, the report said.

Wasted opportunity

However, the members of Scientists for People voiced disappointment over the findings of the committee, saying it wasted an opportunity to nail the company. “The committee’s report reads like a compilation of the information provided by the plant management,” said Dr Babu Rao.

The report was a futile exercise devoid of any actual investigation, he said.

“The root cause of the incident was identified as self-polymerization due to stagnant high polymer content. The actual root cause appears to be the lack of experience of LG Polymers India and their Korean principal, LG Chem, in monitoring and maintaining full tanks of styrene that were kept idle for several weeks,” Dr Rao said.

The report did not cover any aspect regarding international practices in designing, operating and maintaining styrene storage installations and comparing them with those at LG Polymers plant, Dr Rao said.

The committee has not mentioned the condition of other styrene storages at the time of the accident, sampling frequency and analysis of styrene during lockdown period for polymer content to use as guidance to take steps to prevent auto polymerisation, he added.

“Temperature measurement cannot be the only guiding factor to the operator to prevent auto polymerisation. The report failed to throw light on how the tank temperature is to be brought down and what are the future recommendations for faster cooling of the tank before vapour is spread to the environment,” the “Scientists for People” pointed out.

Nexus with government agencies

The social activists suspect a “nexus between the plant management and official agencies” over the former’s expansion plans and called for a thorough probe to ferret out the truth.

“In a glaring lapse, the state pollution control board had last year given for permission for the expansion of the plant operations without apparently obtaining clearance from the Union Ministry of Environment,” the former Union Energy Secretary and environmentalist E A S Sarma said.

“The pollution controls were lax at the plant,” he said.

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In fact, the company was involved in a litigation with the state government pertaining to a portion of the land that it occupies.

“Ignoring this ground reality, the pollution control board reportedly granted consent for establishment and consent for operation for the unit’s expansion,” Sarma said.

He alleged that the South Korean company was “constantly pampered” by the successive governments despite the plant being a highly polluting one and located in the midst of the residential area.