The incident took place yesterday when Anil, a resident of Chamanganj, allegedly kept a leaking gas cylinder inside a water tank at a public toilet here, a police spokesman said.
As the water tank was empty, the leakage continued and spread.
Meanwhile, someone entered the toilet and lit a cigarette which triggered the blaze, he said.
Anil had brought the cylinder for use in his house. But when he opened its cap, gas started leaking and so he kept it in the nearby toilet.
Police rushed to the spot and admitted the injured to hospital where six of them, including two women, succumbed to their injuries.
The deceased have been identified as Vijay (24), Anurag (12), Sita Devi (40), Hasina (48), Anil (24) and Sunil (29), SHO Juber Ahmed said and added that at least four of the injured were in a critical condition.
District Magistrate Roshan Jacob has visited the spot and ordered an inquiry into the incident.
He has also announced a compensation of Rs 50,000 for the deceased and Rs 20,000 for the seriously injured.
