A huge conflagration followed by a blast ravaged a 150-year-old Philadelphia Energy Solutions refining complex in the early hours of Friday, according to the Philadelphia Fire Department.
Eyewitnesses of the blaze took to social media to post horrifying videos of the incident in which a huge cloud of fire rising into the sky can bee seen.
The fire reportedly started between 3 and 4 am and residents of the area said they heard loud blasts.
There have been no immediate reports of any serious injuries so far, according to a Philadelphia Energy Solutions spokeswoman.