A fire broke out at Fortuna Tower, a 10-storey commercial building on Netaji Subhas Road in BBD Bag on Monday morning.

Police said the fire started in Room No. 22 on the fifth floor, which houses the office of Calcutta Rolling Mills (CRM), a company that manufactures steel products, including rolled bars and rods.

Five fire tenders were pressed into service to douse the flames. Several people working in the building were evacuated, and no one was reported trapped or injured.

Prolay Mukherjee, 45, a resident of Bally, said he first noticed thick black smoke near the office window around 10.35am. “That was when we came to know that a fire had broken out on the fifth floor.”

Staff members at the steel manufacturing unit initially tried to control the fire using fire extinguishers before firefighters arrived.