The tank had almost 5,000 kilolitre of petrol, half of its capacity, when it caught fire.
This is the second major fire at IOC storage depots since 2009. On October 29, 2009, a fire broke out at its Jaipur terminal which was blamed on non-observance of normal safety procedures.
The Jaipur depot fire raged for 11 days, killed 11 people and resulted in losses worth Rs. 280 crore.
Senior IOC officials have rushed to Hazira to supervise operations and an inquiry has been ordered to ascertain its causes.
Hazira is a so-called 'white-oil terminal', housing a tank farm to store petrol and diesel. It has five petrol storage tanks and four diesel tanks.
While local administration rushed fire brigade personnel from Surat and nearby cities, IOC has sent fire tenders from its Koyali refinery to douse the fire.
"The fire has been isolated," a company official said. "A high-level team has been constituted to investigate the cause of the fire but our first priority is to put out the fire... efforts are on at war footing."
Senior team from Mumbai office too are rushing to the site of accident.