The fire erupted at an upgrading unit in the Baiji refinery, once the country's largest oil refinery, in Salaheddin province.

The Iraqi government's security media unit said in a statement that firefighters had extinguished the fire.

It added that "one worker was killed and six others were injured."

Local official in Baiji city Adel al-Daj told AFP that the explosion was caused by a technical malfunction.

The Baiji refinery, 200 kilometres (124 miles) north of Baghdad, was heavily damaged in some of the fiercest battles with the Islamic State group after it swept across a third of Iraq in 2014.

After the facility's full rehabilitation, authorities reopened it in February 2024.

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