Engineers battled Friday to prevent more toxic gas escaping at a chemical plant on India's east coast, a day after a pre-dawn leak killed 12 people and knocked locals unconscious in the street.
Although the death toll was lower than feared, the accident which left hundreds hospitalised outside the industrial port city of Visakhapatnam evoked memories of Bhopal where a gas leak killed around 3,500 people in 1984.
Late on Thursday, the evacuation zone around the plant owned by South Korea's LG Chem was widened with hundreds more people in 10 localities brought to safety as a precaution, police said.
"The situation is better now but we can't say it is completely normal. The temperature in the tanks has been brought down by 120 degrees but we need to being it down further by 25 degrees," senior police officer Swaroop Rani told AFP.
"Twelve people have died so far. No one is critical. But we have told those who have recovered that they may go either to their relatives' houses or to shelters that we have set up till the situation is completely normal," she said.
Plant owner LG Chem said Friday there was no fresh leak, but as a precautionary measure nearby people should be moved.
The company "made a request to the police to evacuate residents in case of an emergency if the temperature rises in the tank", it said in a statement issued in Seoul.
"Currently, we are taking necessary measures, such as adding water into the tank" to keep it cool.
Horrifying footage on Indian television showed men, women and children slumped motionless in the streets after the Thursday morning gas escape.
"There was utter confusion and panic. People were unable to breathe, they were gasping for air. Those who were trying to escape collapsed on the roads -- kids, women and all," local resident Kumar Reddy, 24, told reporters.
B K Naik, district hospitals coordinator, said 1,000 had initially been hospitalised. By Thursday afternoon around 600 remained in treatment, with none in a critical condition.
"This is a calamity," Naik told AFP.
AFP photographs taken at the King George Hospital in the city early Thursday had shown two or three patients on each bed, some of them children, and several unconscious.
"I pray for everyone's safety and well-being in Visakhapatnam," Prime Minister Narendra Modi said on Twitter.
The plant, operated by LG Polymers, a subsidiary of LG Chem, is on the outskirts of Visakhapatnam.
The city and the surrounding area are home to around five million people.
The plant had been left idle because of the coronavirus lockdown, according to Rani, an assistant police commissioner in Visakhapatnam.
"(The gas) was left there because of the lockdown. It led to a chemical reaction and heat was produced inside the tanks, and the gas leaked because of that," Rani told AFP on Thursday.
LG Chem confirmed the plant, which makes polystyrene products, was not operating because of the lockdown, but there were maintenance staff at the facility, a spokesman in Seoul told AFP.
Authorities advised people to wear wet clothes and masks, avoid eating uncovered food and consume bananas and milk to "neutralise the effect of the gas".
According to the Centre for Science and Environment (CSE), the gas was styrene, which is likely carcinogenic and combined with oxygen in the air forms the more lethal styrene dioxide.
The leak happened because the gas was not stored at the appropriate temperature, causing pressure to build up and breaking the valve, the CSE said.
The tank was also "old and not properly maintained" and there was no monitoring mechanism installed to specifically detect styrene, it said.
The incident "shows us that there are ticking bombs out there as the lockdown ends and industries start resuming activities," it added.