Both succumbed to their injuries in the hospital where they were admitted, police said.
The gas cylinder exploded at the premises on Tiljala Road near Park Circus railway station injuring 15 others, police said.
All the injured were taken to the Chittaranjan National Medical College for treatment, where doctors said 10 of them sustained 70 per cent burns.
Eight fire engines are at the spot to douse the flames, fire brigade sources said.