Four children who were playing on the roadside were seriously injured after a chemical drum used for road construction exploded in West Bengal’s South 24 Parganas on Tuesday evening.

“The four children named Samiul Molla, Raihan Molla, Riyaz Hasan Molla, and Sadikul Molla are all between the ages of 8 and 10. Suddenly, a drum caught fire in the Madhya Khargachhi area and exploded, raining burning flammable substances down on them,” said a police officer.

Prima facie, the police suspect that a hand-rolled cigarette might have triggered the explosion.

According to police sources, construction work was underway on a 7-kilometre stretch from Ghatakpukur to Chutkir Mor under the Bhangar police station limits. Several chemical drums intended for the project were stored along the roadside.

The police said that one of the drums exploded with a deafening sound. Eyewitnesses reported that one of the children, Sadikul, reeling under agonising pain, jumped into a nearby pond immediately after the explosion.

Residents rushed the injured children to the Nalmuri Block Hospital. As their conditions deteriorated, they were later shifted to M R Bangur Hospital for specialised treatment. One of the children received 85 per cent burn injuries, said an officer.

Soukat Molla, TMC MLA from Canning, said, “Road repair work was underway involving the use of specific chemicals required for pitch dissolution. We are currently investigating the exact role these substances played in the incident.”

A thorough investigation is underway to determine the cause of the blast, the police said.