Four teenagers were injured — three of them seriously — when a barrel containing a chemical meant for mixing with bitumen exploded in Bhangar on Tuesday evening.

The teenagers were crossing Khargachi in Ghatakpur, Bhangar, around 6pm on Tuesday on their bicycles when the explosion occurred.

Police said the barrel blew up after the chemical came in contact with fire from a glowing object, possibly a bidi end.

The barrel with the chemical that was meant to be mixed with bitumen for road repair work in Khargachi had been kept along the roadside. The liquid splashed out following the explosion and hit the teenagers, leaving them with burn injuries.

“One of the four was treated and discharged from Nalmuri primary health centre in Bhangar. Three others were shifted to MR Bangur Hospital with burn injuries. The area has been cordoned off. A search has been launched for the contractor who had undertaken the job of repairing the road,” a senior officer of Kolkata Police said.

As the news reached the control room of the Bhangar division of Kolkata Police, senior officers rushed to the spot and shifted the injured on ambulances first to the primary health care centre and later to Calcutta.

“The identities of the injured are being established,” the officer said.