Four people were seriously injured in an explosion at a firecracker manufacturing unit in West Bengal’s South 24 Parganas district on Saturday, police said.

The blast occurred around 1 pm at the factory in the Champahati area and caused extensive damage to the unit as well as nearby houses, a senior officer of the Baruipur Police District said.

Three of the injured have been identified as Gaur Gangopadhyay, Kishan Mondal and Rahul Mondal, while the identity of the fourth person is yet to be confirmed, he said.

"They suffered burn injuries and were immediately admitted to hospitals in Baruipur and Kolkata for treatment," the officer said.

Several fire tenders were pressed into service to douse the fire that broke out following the explosion, he said.

Locals claimed the blast was deafening and so powerful that it blew off the asbestos roof of the factory.

"The cause of the explosion is yet to be ascertained. A probe has been initiated," the officer said, adding that samples from the site were collected for forensic examinations.

A preliminary investigation suggests that mishandling of explosive materials by unskilled workers might have triggered the blast, he said.

The firecrackers were reportedly being manufactured for wedding purposes, the officer added.

An explosion had earlier occurred at a firecracker manufacturing unit in Champahati in December 2024, triggering panic among local residents.