No casualty was reported.
A security guard, who saw smoke emanating from the ground floor, alerted fire personnel around 4.30am. Fire tenders from T Nagar, Egmore, Kilpauk and other placeswere rushed to the spot.
Twelve men who were working in the canteen on the seventh floor were rescued using a skylift in the morning.
Smoke kept emanating from all seven floors of the building. Efforts were on to extinguish the fire.More than 70 fire and rescue services personnel were battling the blaze.
Firemen said the fire could have been caused by an electric short circuit. However, the exact cause was yet to be ascertained.
Police said there were cracks on the building