Four members a family including a woman and a child were burned in a gas cylinder explosion in Daudkandi of Comilla early Tuesday.
The injured are Monowara, 60, Zill Haque, 37, Umme Humaira, 30, and two-year-old Hurram.
The victims were rescued and taken to the emergency department of the National Burn and Plastic Surgery Institute around 6am, hospital sources said.
Resident Surgeon Dr Shawon Bin Rahman said they were brought from Daudkandi area in burned condition early in the morning.
He said Monowara suffered 2% burns, Zill Haque 54%, Umme Humaira 65% and child Hurram 6%.
The condition of Zill Haque and Umme Humaira is critical due to the extent of their burns, the doctor added.