The injured were identified as Fatema Begum, 40, her daughter Sadia Akter, 20, and sadia's daughter Israt, 11.
They were admitted to the National Institute of Burn and Plastic Surgery, hospital sources said.
The explosion occurred in the early hours when Fatema was cooking, and a gas leak triggered the blast, said Jannatul Ferdousi, sister of Fatema.
Fatema, her daughter Sadia, and granddaughter Israt were injured in the incident.
They were later rescued and taken to the hospital, she said.
Fatema said the family is originally from Lalmohan upazila in Bhola and had been living in a rented house in Chandrima Udyan with Sadia’s husband Ismail.
Dr Shawon Bin Rahman, Resident Medical Officer of the burn institute, said all three victims were admitted after receiving primary treatment.
Fatema and Sadia each suffered 7 percent burns, while Israt sustained 30 percent, reports UNB.
"All three have facial burns, and Israt’s condition is critical," he added.