The injured were identified as Shahadat Bhuiyan, 55, Md Mizan, 38, and Golam Mawla, 51.
Shahadat’s cousin said a gas cylinder exploded in their house, leaving the trio injured.
Agrabad Fire Service Deputy Assistant Director Farid Ahmed Chowdhury said on information, they rushed to the spot and rescued the injured people.
Sub-inspector Jahirul Haque of Chattogram Medical College Hospital (CMCH) police outpost said they were admitted to the Burn unit of the hospital.
Among the injured, Golam Mawla and Mizan suffered 65 percent and 50 percent burn injuries respectively, said Dr Mohammad Khaled, Assistant Professor of CMCH Burn and Plastic Surgery Unit.
They were referred to Dhaka Medical College and Hospital (DMCH) for better treatment, he said.