The injured were identified as Md Tuhin Hossain, 38, his wife Eva Akter, 30 and their two sons—Tanvir, 9 and Tawhid, 7 of Madaripur district.
A fire broke out after the air-conditioner of a room exploded with a big bang around 1 am, leaving all four members of the family injured.
Later, they were taken to the National Institute of Burn and Plastic Surgery.
Shaon Bin Rahman, resident surgeon of the National Institute of Burn and Plastic Surgery, said among the victims, Tuhin received 47% burn injuries, while Eva with 15%, Tawhid 8% and Tanvir 40% burn injuries, reports UNB.