The synthetic chemical styrene leaked from the LG Polymers plant in a city on India's Bay of Bengal coast while workers were preparing to restart the plant after the coronavirus lockdown was eased, Administrator Vinay Chand said.
A fire that broke out before the gas leak has been extinguished, and police said the gas leak was later stopped and the air had cleared.
Chand said several people fainted on the road and were rushed to a hospital.
Nearly 100 people are hospitalized in non-life-threatening condition, Police Commissioner R.K. Meena said.
The dead included an 8-year-old girl. Meena said one person died falling into a well while running away and another person died after he jumped from the second story of his house to escape. The others died in a hospital
South Korean company LG Chem operates the plant in Vishakhapatnam, Andhra Pradesh state. The company said it is cooperating with Indian authorities to help residents and employees.
“The gas leakage is now under control, but the leaked gas can cause nausea and dizziness, so we are investing every effort to ensure proper treatment is provided swiftly,” LG Chem said in a statement.
LG Chem is looking into what caused the leak of styrene monomer gas, which is used for producing plastic, but wouldn’t exactly know until Indian authorities complete their investigation, company official Song Chun-seob said.
It employs around 300 workers at the Vishakhapatnam plant, but Song said the victims mostly appeared to be local residents.
Nearly 1,000 people in an area of 3 kilometres (1.8 miles) complained of breathing difficulties and burning sensation in their eyes, Chand said.
Authorities deployed 25 ambulances to shift the sick to hospitals and others away from the accident site.
Meena said nearly 3,000 people were evacuated from a village near the plant.
Images from television showed people lying in the streets after they collapsed while trying to flee.
An eyewitness said there was a total panic as a mist-like gas enveloped the area. “People felt breathless in their homes and tried to run away. Darkness added to the confusion,” he told a television channel. His name wan’t given by the channel.
Srijana Gummala, the local municipal commissioner, said water was sprayed in the area to minimize the impact of the gas. “Through public address system, the people are being asked to use wet masks,” he said.
India imposed a strict, nationwide lockdown on March 25 to control the spread of coronavirus. Measures were eased on Monday, allowing neighborhood shops and manufacturing units to reopen to resume economic activity.
India has so far reported nearly 50,000 virus cases with 14,183 recovered and 1,694 deaths.