The injured are Arab Ali, 50, Hasina, 40, wife of Arab Ali, Arab's son Abdur Rab, 26, his wife Nipa, 24 and their one and half-year-old daughter Ayesha.
Bachhu Mia, in-charge of Dhaka Medical College Hospital police camp, said a fire broke out in the house when a gas cylinder went off with a big bang around 7:00 am, leaving five people injured.
The gas cylinder blasted when Hasina was trying to light a stove, he said quoting family members.
Later, they were taken to the burn unit of Dhaka Medical College Hospital.
Of the injured, Arab Ali sustained 60 percent burn injuries while Hasina 96 percent, Abdur Rab 88 percent, Nipa seven percent and Ayesha 32 percent, said doctors of the hospital.