Explosion reported at Italian oil refinery, residents warned to stay indoors (PHOTO, VIDEOS)

An explosion has been reported at one of Italy’s biggest oil refineries in Sannazzaro de' Burgondi, near Pavia, about 40km south of Milan.

Local authorities have ordered residents to stay indoors while an emergency plan is activated.

The Department of Civil Protection in the Province of Alessandria says nearby emergency centers have been activated for monitoring and supervision, but people are advised to remain indoors in the meantime.

Local authorities have warned that the clouds of smoke are being pushed by winds towards Voghera, about 30km (19 miles) south of Sannazzaro, and are expected to remain over the site for the coming hours.

The fire at the Eni refinery broke out at around 3.40 p.m. generating a ball of fire tens of meters high, according to eyewitnesses cited by Il Giorno. Images and footage from the scene show an enormous column of black smoke rising overhead.

Eni has issued a statement saying efforts are underway to extinguish the fire and there have been no reports of any injuries. The company also said the cause of the blast is under investigation.

The local health authority (ASL) says the refinery explosion poses no health risks to residents, according to La Provincia Pavese. The Civil Protection Service said first analyses have revealed no particular concentrations of pollutants in the air in nearby areas of Tortona and Castelnuovo.

The fire, which broke out in the East Shipyard refinery area according to Il Fatto Quotidiano, comes after a similar incident in July where a worker suffered burns following an explosion at an older part of the plant.