Seven workers of two factories suffered burn injuries in two separate fire incidents at Keraniganj and Kadamtoli in the capital yesterday.
Of them, five were said to be in critical condition.
All of them were sent to the burn unit of Dhaka Medical College Hospital (DMCH).
In Keraniganj, a fire broke out at Giasuddin Embroidery Factory at Telghat when its boiler exploded around 1:30am. All the factory staff were asleep inside, police said.
Three workers of the factory - Sujan, 20, Awal Hossain, 30, and Badsha, 17 - were rushed to the DMCH in critical condition.
Later, with the help of locals, firefighters doused the blaze.
In a separate incident, a boiler exploded at a small steel re-rolling mill at Kadamtoli in the capital, leaving four workers critically injured.
The fire broke out around 1:30am at Salam Steel Re-rolling Mills, where workers were working night shift.
Bulbul, Motin, Mahbub and Sayeed received severe burn injuries. They were rushed to the DMCH. All the workers got more than 80% of their bodies burnt. No cases were filed in connection with the incidents.