A huge explosion at a firecracker factory at Nadia district’s Kalyani on Friday killed four persons, including two women, the police said.

After the explosion, senior police officers rushed to the spot with the fire brigade. Residents said the fire broke out at the manufacturing unit of the factory after the explosion.

It took the fire brigade an hour and half to douse the flames. Meanwhile, a forensic team has reached the spot and collected samples.

A senior police officer said, “The explosion has damaged the entire factory.” The police have said that the preliminary investigation points at a short circuit which may have caused the fire.

Eyewitnesses said the explosion took place around 1 pm in the Rathtala area of Kalyani. Those who died in the blast were employees of the factory, theresidents claimed.

The officer said, “It was a very crowded area and we got information that the factory did not have proper permissions. We are investigating how it managed to operate.”

The Kalyani municipality has also set up a committee to look into how the factory was running in such a congested area.

Since 2023, West Bengal has seen several incidents of explosions at firecracker factories. In the last six months, such incidents have taken place at Champahati and Diamond Harbour in South 24 Parganas district.