PHILADELPHIA - A large fire broke out early Friday at an oil refinery in Philadelphia, rattling the area with at least one booming explosion and lighting up the dark sky with huge balls of gas and flame.
The explosion and fire came from a vat of butane at Philadelphia Energy Solutions, starting around 4 a.m., city Deputy Fire Commissioner Craig Murphy said.
PES fire crews have been fighting the flames - with city fire crews in support - and the fire has been contained to the general vat area, Murphy said.
"The fire is not under control, yet right now companies are making sure that the fire does not spread," Murphy told reporters after dawn.
By 7 a.m., the flames were significantly lower, video from CNN affiliate WPVI showed - a stark contrast to the massive fireball that bystanders recorded on social media earlier in the morning.
One worker complained of chest pains after the fire started, but that person did not need to be taken to a hospital, and no other injuries have been reported, Murphy said.
Details about what started the fire weren't immediately available. Authorities are working to account for all of the personnel, Philadelphia Energy Solutions spokeswoman Cherice Corely said - though Murphy said no one who'd been at the facility is missing.
Residents reported several explosions that were felt in South Jersey and Delaware County, Pennsylvania, according to WPVI.
Emergency management officials initially asked people east of the fire to shelter in place, but by 7 a.m., that order was being lifted, Murphy said.
PES had an industrial hygenist take air-quality readings, and the area "is clear," Murphy said. The company will continue to monitor the air in neighborhoods to the east.
Portions of the I-76 expressway and the city's Platt Bridge were temporarily closed after the fire, according to the city's Office of Emergency Management.
The facility is the 10th largest in the US and is the largest oil refining complex on the Eastern seaboard, according to its website. Philadelphia Energy Solutions employs more than 1,000 people and refines 335,000 barrels of crude oil a day.
Butane is one of the products -- along with gasoline, heating oil and propane -- that comes from the process of refining crude oil.