A fire that engulfed a Philadelphia refinery and sparked air-quality concerns has been extinguished, according to city officials.
The fire at Philadelphia Energy Solutions was put out on Saturday afternoon, according to a statement on the city's website.
The fire began with an explosion on Friday morning from a vat of butane and propane. Residents reportedly felt the explosion in South Jersey and Delaware County, Pennsylvania, according to CNN affiliate WPVI.
Emergency medical services treated one individual on the scene, according to Fire Commissioner Adam Thiel. Four employees also suffered minor injuries, and all were treated on-site by a company medical team, according to Philadelphia Energy Solutions.
The fire sent large plumes of smoke into the sky that could be seen for miles. Emergency management officials initially asked people east of the fire to shelter in place, but the order was quickly lifted.
It's not clear what caused the explosion, but investigations will begin on Monday, the Philadelphia Fire Department and Office of Emergency Management said in a statement.
The Occupational Safety and Health Administration; Bureau of Alcohol, Tobacco, Firearms and Explosives; and the US Chemical Safety and Hazard Investigation Board will be involved in the investigation, the city said.
James Garrow, spokesman for city's Department of Public Health Air Management Services Lab, said on Friday that officials were monitoring air quality but were "not aware of any immediate danger from the fire."
"Preliminary testing both at the site of the refinery and in the adjacent community has shown no ambient carbon monoxide, hydrocarbons (combustibles), or hydrogen sulfide," Garrow said.
The Fire Department's hazmat unit and Department of Public Health are continuing to monitor air quality around the refinery.
Philadelphia Energy Solutions is the 10th largest refinery in the US and refines about 335,000 barrels of crude oil a day, according to the company's website.