The Mackinnon & Mackenzie building, in the Central Zone, which houses offices of some of the major companies, like the ITC, Williamson Magor & Company Private Limited, Unit Trust Of India, Steel Authorities of India, National Insurance, and Indian Bank, happens to be one of the oldest office buildings in the area.

The fire, which is suspected to have ``started around 2.30 am'', spread into 3rd, 4th and 5th floors causing damages to the offices of these companies. It's not known yet how the fire broke out. Both the police and fire brigade officials, who fought the fire for over 11 hours with 40 fire tenders, feel the immediate reasons of the fire could be short-circuit in the electric lines. ``Only forensic investigation can ascertain theexact cause of the fire,'' Deputy Commissioner of Police Raj Kannojia, Central, told The Indian Express.

According to the West Bengal Fire Services officials, who have been fighting the fire since 3.30 am, the massive building had `no emergency fire-fighting provisions.'