While the cause of the blaze is yet to be ascertained, the fire brigade official said that there was no report of casualty or anyone being trapped inside the factory.
Preliminary findings suggested that the blaze was caused by an electrical short-circuit on the 13th floor of the New Koilaghat Building, owned by Eastern Railway (ER).
Meanwhile, the detective department of the Kolkata Police on Tuesday initiated its probe into the case, and a special investigation team has been formed for the purpose.
Dhankar felt that there is a need for modernisation of fire and municipal services in Kolkata, which is a major city in the country and the world.
Most of those killed are first responders -- four firefighters, one assistant sub-inspector posted at the Hare Street police station and an RPF personnel, officials said.
At least nine people, including four personnel of the fire department, two Railway personnel and an ASI died in the incident at a 13-storied-office building of the Eastern Railway.
The blaze broke out at the New Koilaghat building, which is shared by the Eastern Railway and the South Eastern Railway, Eastern Railway spokesman Kamal Deo Das said.
Locals claimed that more than 700 people living in around 150 shanties have been rendered homeless by a blaze that erupted on Wednesday evening.
Twenty-seven fire tenders took around four hours to control the blaze that broke out around 6.55 pm in the Hazari Bustee on Kshirode Vidyavinode Avenue beside the Bagbazar Women's College.
The fire was doused completely within an hour, a Kolkata Police officer said.
The news of the inferno was informed to the fire brigade at 6.38 pm but there is no report of any casualty so far, the sources said.
Four fire tenders were pressed into service to douse to the flames -- spotted around 4.40 am -- the sources said.
At least six fire tenders were pressed into service to control the blaze, which was first spotted around 3.30pm, a fire department official said.
The blaze broke out in the first floor of the building located in the northern part of the city. It has also spread towards the upper floor, a Fire Brigade official said.
Ten fire tenders are present at the spot, and fire fighting operations are underway.