The fire broke out in a major crude oil tank on Wednesday night before spreading to a second refinery on a road southwest of Arbil, capital of the autonomous northern region of Kurdistan, the civil defence agency said.

Thick plumes of black smoke and balls of orange flame rose into the sky above the facility, an AFP photographer reported.

The civil defence agency said the fire, the cause of which remains unclear, "started in one refinery before spreading to another".

A spokesman for the agency, Shakhwan Saeed, told a news conference on Thursday evening: "The fire has been 100 percent contained, and there is no longer any danger for the surrounding refineries."

He said 150 rescuers had been mobilised and 14 had been injured, with two in "critical condition".

Arbil governor Omed Khoshnaw earlier said three rescuers were being treated in hospital for burns and another 10 suffered breathing difficulties.

The main storage tank that was impacted contained more than 5,000 tonnes of fuel, he said, putting the estimated cost of the damage caused at $8 million.

The Arbil civil defence said four fuel tanks as well as three fire trucks were burned.

"So far, we don't know what caused it," said Khoshnaw, adding that it could have been an electrical short circuit.

Saeed noted that the facility did not meet "any of the standards" set by the civil defence agency for safety.

With Iraq experiencing scorching summers, the country has seen multiple fires in recent weeks, affecting shopping centres, warehouses and hospitals.

Iraq is one of the world's biggest oil producers and crude oil sales make up 90 percent of budget revenues.

But exports from the Kurdistan region have been halted for more than a year in a dispute over legal and technical issues.