Four members of a family, including two children, sustained burn injuries in an explosion while cleaning a water tank at a residence in the Tannery intersection area of Hazaribagh's Jigatola on Saturday evening.
The injured were labourer Belal Hossain, 28, Md Ziaur Rahman, 45, and his daughters Faria, 8, and Raifa, 4.
They were taken to the emergency department of the National Institute of Burn and Plastic Surgery around 10:45pm on Saturday.
Md Shahporan, who brought the injured to the hospital, said a worker was cleaning the reserve tank at the house when the explosion took place as an electric bulb was turned on inside the tank, presumably due to accumulated gas.
They were first taken to a local hospital and later transferred to the burn institute.
Dr Shawon Bin Rahman, resident surgeon of the institute, said Belal sustained 17% burns, Ziaur 4%, Faria 5%, and Raifa 6%.
All are currently out of danger and receiving treatment at the emergency unit, he added.