Three child workers died in a blaze in an illegal firecracker factory at Narayanpur, near Nilgunge market, in Barasat, on Tuesday afternoon.

Police said the factory was run by Zulfikar Ali, who lives in an adjacent house.

Despite a ban on child labour, minors are hired in large numbers by a chain of illegal cracker factories in Barasat.

An officer in the fire department said the blaze had spread from gunpowder kept in the factory.

“Ali had been running the illegal unit for a few years,” said S. Chakrabarty, the officer-in-charge of Barasat police station. The victims have been identified as Shahrukh Ali, 10, Hasan Ali, 11, and Shahnara Khatun, 11.

Neighbours said they heard an explosion and saw smoke billowing from a room near Ali’s house around 12.35pm. Rushing to the spot, they saw three child workers trapped in the blaze.

“We tried to put out the fire by splashing buckets of water, but failed. Fire-fighters later arrived and brought the blaze under control,” said Aruna Mondal, a local resident.

Nineteen tenders had rushed to the spot from Barasat, Barrackpore and Belghoria.

After putting out the blaze, the firemen extricated Shahrukh, Hasan and Shahnara. While Shahrukh died on the spot, the other two were admitted to Barasat district hospital with more than 80 per cent burns. They died of cardiac failure a few hours later.

Local residents alleged that there are around 150 illegal cracker factories in Barasat, none of which has taken any fire-safety measures.

“Two persons died in a fire in an illegal factory last year,” said a senior police officer.