A combo image shows thick black smoke billowing from the fire site.

Firefighters battled to contain the towering pillars of fire, which burned several cars. Video circulating on social media showed clouds of dense, black smoke billowing over the desert road that stretches from the capital, Cairo, to the city of Ismailia, on the Suez Canal.

Egypt’s Health Ministry said 12 people suffering burns and smoke inhalation were rushed to a hospital for treatment, and all hospitals near the site were preparing to receive more injured.

A torrent of crude oil leaked from the broken Shuqair-Mostorod pipeline into the thoroughfare, where a spark from the heavy traffic ignited the fire, Egypt’s Petroleum Ministry said. It said authorities managed to close the main valves and extinguish the fire.

The ministry said it would investigate to determine the exact reasons for the rupture.

Crude and petroleum products flow through Suez Canal daily.

In one such accident last fall, thieves were trying to siphon off gasoline in the Nile Delta province of Beheira when leaked fuel caught fire, killing seven.