The mishap took place when the blaze started at about 4.20 PM yesterday in four-storeyed 'Gokul Nivas', an over a century old commercial-cum-residential building, located in densely-populated Kalbadevi area.
When the flames were being doused, the building which is in a dilapidated condition could not withstand the force of the water, and crumbled trapping the four under rubble, an Municipal Corporation of Greater Mumbai (MCGM) official told PTI today.
They are identified as Chief Fire Officer Sunil Nesarikar and Deputy Chief Fire Officer Sudhir Amin, who have suffered 50 per cent and 80 per cent burns respectively.
Three civilians were also injured in the incident.
According to the official, who is associated with the Disaster Management unit of the MCGM, the blaze started at about 4.20 PM and it took fire personnel over 7 hours to put out the flames.
He said the building became weaker with the force of water and finally crumbled, trapping four fire officials under the debris.
"At about 7 PM, portions of the building started collapsing (as a result) four fire officials got trapped under the debris, and the fire fighting operation turned into a rescue operation. While two officials could be saved, two others died of asphyxiation," the official said.
The official said the cause of fire is being investigated.
"This building had both the residential and commercial apartments. The fire started at a cloth godown on the ground floor and later spread to the upper floors of the building through wooden beams and columns," the official said.
