Overheating, corrosion likely responsible for styrene gas leak
The styrene gas leak from a chemical factory owned by LG Polymers India Pvt Ltd in Andhra Pradesh’s Vishakhapatnam has put the spotlight on the lack of safety precautions to avoid such leaks. Eight people died and more than a thousand are hospitalised after the leak early morning May 7, 2020.
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 an extra 250 tonnes per day (TPD) from the current 415 TPD.
This proposal brings to notice that regulators evaluated several aspects concerning pollution. No guidelines, however, were set over the leakage of raw materials or hazardous chemicals.
Styrene — a raw material used in the production of plastic products like PVC pipes, cups and plates — is produced in petrochemical processing refineries. The styrene gas leak reportedly occurred because of overheating, leading to pipe leaks.
The factory was starting operations again after the nationwide lockdown to curb the spread of the novel coronavirus disease (COVID-19) was relaxed.
“It is a red category (highly polluting) industry. The Chairman of the Andhra Pradesh Pollution Control Board (PCB) and a team has accompanied the state’s chief minister on ground today,” said the state’s PCB office.
A few industry experts suspected corrosion to be responsible for the leak.
The storage tank carrying line corrodes because of the abrasive nature of the chemicals, said an expert working with Reliance Industries. Money is needed every year for maintenance, while most industries don’t want the extra expenditure, according to the expert.
“The patch work also lets things remain unnoticed for a long time. Also, the emergency detection system is either not there, is not working or is made locally,” the expert added.
The industry association requested for a careful restart of operations. Ravi Kumar Agarwal, the president of the All India Plastic Association, requested all plastic processing facilities to pay more attention while restarting their plants.
Checking temperatures and ensuring safety protocols while restarting industries are very essential, he said. “Moulders, extruders and other equipment that uses any element for heating — electricity, gas or any fuel — must be carefully checked,” Agarwal said.
Appropriate remediation of the impact area, complete evacuation and the use of wet masks was also advised.
Styrene levels in the air should dip below four parts per billion (ppb) before rehabilitating the local population, said Thava Palanisami, senior scientist at the Global Centre for Environmental Remediation at the University of Newcastle in Australia.
“Styrene at the levels of 300-375 ppb for a short period can cause neurological disorders and levels less than this can cause other health impacts,” he said. Styrene stays in air for weeks and is highly reactive, Palanisami said, adding that it can combine with oxygen to form styrene dioxide which is more lethal.
“The presence of other pollutants can also affect reactivity. Operating one reactor in full load can also lead to such disasters,” he said.
Risks were unavoidable while operating petrochemical units, which is why countries in the European Union are moving towards green approaches such as bioplastics which will reduce the demand for toxic chemicals such as styrene, according to him. “Research is still underway on biodegradable bioplastics using agricultural wastes, which could replace polystyrene,” he said.
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