Locals complained of a stinging smell at 7 pm, which was later traced to the godown.
Two women in their 70s died on Tuesday night after inhaling poisonous gas leaking from the godown of a closed factory in Asansol, West Bengal.
At least 22 people were also hospitalised, among them a four-year-old child. The condition of at least seven of them is critical.
Some claim the godown was being used as a garage and several cylinders of gas used for welding were stored in the premise.
Locals at the Gopalpur area of Asansol complained of a stinging smell around 7 pm, which was later traced to the godown. The police and the fire brigade were called in immediately.
Three fire tenders arrived at the spot soon after but at least four firemen were also affected by the gas. Efforts were on till late tonight to seal the source of the gas.
Asansol MP, BJP's Babool Supriyo said that the police must investigate as to how such a large quantity of poisonous gas was stored in a densely populated locality.
Foam was being used to plug the leak.
Many locals fled the area and planned to stay away for the night.