The blast took place on Sunday evening at around 8.30 pm, police said. (Representational)
Three women of the same family, including a minor were killed and several persons were injured in a blast at an illegal firecracker manufacturing unit at Budge Budge, about 26 km from the city, police said.
The blast took place on Sunday evening at around 8.30 pm and the three killed are 65-year-old Jamuna Das, her daughter Pampa Ghati and her 10-year-old grand daughter Jayashree, the police of South 24 Parganas, under which the area falls, said on Monday.
The incident was the second of its kind in West Bengal in a week.
The state government ordered a CID probe into the incident on Monday, a senior official confirmed.
The police official said that according to the preliminary investigation, the blast may have occurred from the fire of incense sticks lit in the 'puja room' on the terrace of the house, where it took place.
"It seems that the blast occurred after the explosives illegally stored in the house caught fire, which probably spread from incense sticks lit in the evening in the puja room located on the terrace of the house," he said.
At least 30 people, allegedly running illegal firecracker manufacturing units in the locality, were arrested and a large quantity of explosives stored in different houses were seized during police raids throughout the intervening night of Sunday and Monday, the police official said.
The number of injured in the blast was, however, not specified.
The three women were on the terrace of the single storied house where the incident took place.
"Three women, including a minor, were declared brought dead when they were taken to a nearby ESI hospital. All of them had suffered third degree burn injuries from a blaze which was reported from the terrace of their house, where an illegal firecracker factory was operated," a senior police officer of Diamond Harbour police district told PTI.
"We have conducted raids in the area and seized at least 20,000 kg of explosive materials used to manufacture firecrackers and arrested more than 30 people for their involvement in running such illegal businesses. Raids are on and police are investigating the cause of the fire," the officer said.
Contradicting the police, locals in the area claimed that the seized explosive materials were "purchased legally" and they are "license holders" for manufacturing firecrackers. "This is torturous. We are license holders for firecracker manufactures. We had purchased all the explosive materials seized by the police ... The police have wrongfully seized them. We are poor people and this will definitely ruin our livelihood," the owner of a firecracker manufacturing unit in the locality, Sajal Das said.
I Budge Budge area has a thriving fireworks industry and the now banned 'chocolate bomb' manufactured at Nungi near it was a popular firecracker during Diwali.
BJP leader Suvendu Adhikari mocked the state government after the blast and as in the case of the Egra blast, demanded an NIA probe into the incident .
He also alleged that the state police had tampered with evidence in the night while conducting the raid.
On May 16 an explosion had taken place at an illegal firecracker manufacturing unit at Egra in Purba Medinipur district in which 12 people lost their lives.
The main accused in the Egra blast died at a hospital at Cuttack in Odisha on May 19.
(Except for the headline, this story has not been edited by NDTV staff and is published from a syndicated feed.)