A large fire took hold of a Philadelphia oil refinery in the early hours of Friday morning.
No one was injured during the incident in the south of the city but the flames could could be seen for miles around.
One eyewitness said: "And I seen the sky light up. The whole sky lit up yellow. And when I came over to this side of... the avenue, that's when I seen this explosion and I seen a second explosion and I seen a third explosion.
"Third explosion rocked my truck. The whole truck started to rock. And it got kind of scary. But the blast from the third one was the biggest blast. That's the one that shook everything."
Philadelphia Energy Solutions Refining Complex where the inferno took place has it's own fire brigade, which responded to the incident.
Around 335,000 barrels of crude oil are produced at the complex on a daily basis.
Jonathan Villanueva, an eyewitness, explained: "As I saw a light out in front, I was like look at that. What's that? The sun's coming up already? And then it started coming up really fast and it was a massive, just a massive fireball. Lit up the whole sky, everything."
Authorities are yet to ascertain the cause of the fire.