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The Centre for Science and Environment (CSE), a Delhi-based think tank, has come out with an assessment of the styrene gas leak that occurred in the plant of LG Polymers India Pvt Ltd early morning May 7, 2020.
CSE — in its first assessment released at 3.30 pm — has attributed the accident to the company’s negligence and in not adhering to safety protocol. Based on the detailed note by CSE, below is a low down on the gas leak that has already killed 10 people.
How toxic is Styrene?
Styrene — an organic compound used in the production of polymers, plastics and resins — is manufactured in petrochemical refineries. It is, likely, a carcinogenic substance that can react with oxygen in air to mutate into styrene dioxide, a substance that is more lethal.
According to The Manufacture, Storage And Import Of Hazardous Chemicals Rules, 1989, styrene is classified as a toxic and hazardous chemical.
Acute (short-term) exposure to styrene in humans results in mucous membrane, eye irritation and gastro-intestinal effects. Chronic (long-term) exposure results in effects on the central nervous system (CNS), including headaches, fatigue, weakness, depression, CSN dysfunction, hearing loss and peripheral neuropathy. If it goes beyond 800 parts per million, the person can go into a coma.
The duration of the exposure and its relative concentration determines toxicity: We currently know that roughly three tonnes of gas leaked from the plant’s styrene storage tank and the feeding line. We now need to determine exposure.
Styrene stays in air for weeks and is highly reactive, according to Thava Pananisami, senior scientist at the Global Centre for Environmental Remediation (GCER) and Cooperative Research Centre for Contamination Assessment and Remediation of the Environment (CRC CARE) at the University of Newcastle in Australia.
“It can combine with oxygen to form styrene dioxide, which is more lethal,” he said.
“The presence of other pollutants can also affect reactivity. Operating one reactor in full load can also lead to such disasters,” he added.
How did this happen?
Styrene monomer (a single unit of styrene) was used at the manufacturing plant to produce expandable plastics. The storage requirement of styrene monomer strictly mentions that it has to be below 17 degrees Celsius.
There was a temporary and partial shutdown of the plant because of the nationwide lockdown to curb the spread of the novel coronavirus disease (COVID-19) pandemic, excluding maintenance activities that were being carried out according to a pre-determined schedule.
The leak occurred as a result of styrene gas not being kept at the appropriate temperature. This caused a pressure build-up in the storage chamber that contained styrene and caused the valve to break, resulting in the gas leakage.
The container that was being used to store styrene gas was old and not properly maintained. This non-maintenance of the facility resulted in three tonnes of styrene leaking into the surrounding areas.
Another issue was a defunct volatile organic compound (VOC) detection system at the plant. There is no monitoring mechanism installed to specifically detect styrene.
The facility is spread over 600 acres of land, that includes nearby residential areas. It is spread over 231 acres, according to terms of reference submitted by the company in 2018. The impact zone has been in the range of 2-3 kilometres.
There is a revenue village and the facility is surrounded by residential areas, resulting in a higher rate of gas exposure. The casualties are yet to be confirmed. They are, however, currently said to be around nine, with the majority of them being children.
The most important immediate treatment is to give oxygen to affected people. The people in the zone also need to be evacuated as long-term exposure can be detrimental to their health. Also, as styrene reacts to form styrene dioxide, the air could remain contaminated for some time. However, the winds blowing from the sea could also help disperse the gas.
The factory had submitted a Rs 168 crore proposal in 2018 to the Union Ministry of Environment, Forest, and Climate Change to expand its production capacity by another 250 tonnes per day (tpd) from the current 415 tpd. This permission, as we understand it, has been recently granted.
What are the guidelines on storage of hazardous chemicals in plants?
After the Bhopal disaster, many legislations were enacted starting from the Environment (Protection) Act, 1986 to the Public Liability Insurance Act, 1991. According to Manufacture, Storage And Import Of Hazardous Chemical Rules, 1989, styrene is classified as a hazardous and toxic chemical.
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Did LG Polymers India Pvt Ltd not follow stipulated rules?
There are clear rules on hazardous chemical storage under the Environment Protection Act, 1986.The unit is a ISO certified which means it has protocol for everything.
However, what seems to be the case, is that the plant management, in its haste to re-start the plant has ignored the protocol of doing maintenance of the plant before resuming operation. This combined with the lack of proper storage of the gas – not maintained at the temperature required --faulty fixtures could have resulted in the accident.
Not only Vizag: Other plants as well
This shows us that there are ticking bombs out there as lockdown ends and industries start resuming activity. Therefore, immediate directive must go to all units to ensure safety while resuming activity and also in case the lockdown continues, these safety precautions must not be negated.