Duty officer at the Fire Service Central Control Room Ziaur Rahman said the fire originated at the chemical godown on the ground floor of a five-storey building at Churihaat around 10:38pm.
On information, 32 fire-fighting units rushed in to douse the flame, he said.
The reason behind the fire could not be known yet.
He said firefighters were trying to bring the blaze under control.
The task has become difficult due to the narrow road in front of the building, Ziaur said.
Talking to UNB around 1:38 am on Thursday, Mahfuz Riben, duty officer of the control room said the fire was still razing.
The injured were taken to Dhaka Medical College Hospital (DMCH) and Mitford Hospital, said Bacchu Mia, in-charge of DMCH police camp.
Of the injured, 12 suffered burn injuries and others were injured while jostling for getting out of the building, he added.