PHILADELPHIA — A series of explosions and a spectacular fire ripped through a South Philadelphia oil refinery early Friday, rattling windows, injuring five workers, unnerving the city and causing gasoline markets to spike on speculation of fuel shortages.
The accident at Philadelphia Energy Solutions (PES), the East Coast’s largest refinery, injured five workers, who were treated at the scene. But safety advocates said the public danger could have been far worse had the blast released a cloud of hydrogen fluoride, a deadly chemical used in the refining process.
The U.S. Chemical Safety and Hazard Investigation Board (CSB), an independent federal agency, announced Friday it was dispatching a four-person team to Philadelphia to investigate the incident, which was similar to refinery accidents in Torrance, Calif., in 2015 and in Superior, Wis.., last year that came perilously close to releasing hydrogen fluoride. The Wisconsin accident prompted a temporary evacuation of residents.
“Philadelphia and surrounding communities appear to have narrowly dodged a catastrophe this morning,” Joseph Otis Minott, executive director of the Clean Air Council, said in a letter calling for the CSB to investigate.
PES said three separate explosions “impacted” a unit that produces alkylate, which is used to boost gasoline octane. The refinery complex has two alkylation units, and the unit that was involved in the conflagration uses hydrogen fluoride — also known as hydrofluoric acid — as a catalyst. A 2009 release of just 22 pounds of the chemical at the South Philadelphia refinery sent 13 contract workers to the hospital.
“Hydrogen fluoride is extraordinarily dangerous,” said Fred Millar, an Arlington, Va.-based chemical disaster expert and independent consultant. City officials said none of the material was released in Friday’s accident.
The accident at about 4 a.m. Friday lit up the predawn sky with a fireball so gigantic that it was captured by a weather service satellite. Preliminary testing at the refinery “found no ambient carbon monoxide, hydrocarbons (combustibles), or hydrogen sulfides,” according to the city Office of Emergency Management, which is awaiting results from additional air pollution testing from the Air Management Services lab.
The fire quickly escalated to a third alarm. Murphy said the firefighters contained the fire to the alkylation unit and to cooling surrounding pipes and tanks with water. He said 120 Philadelphia firefighters and 51 pieces of equipment were involved in the operation.
“It is standard practice when fighting a fire of this type to let the flammable gases burn away in a controlled fashion,” Fire Commissioner Adam Thiel said.
The cause of the explosions is not yet known. The Fire Marshal’s Office will investigate once the incident is over and the scene is safe to enter, Thiel said. The fire originated in a propane tank, said Cosmo Servidio, Environmental Protection Agency head for the Mid-Atlantic, adding that “No other tanks were affected.”
“We have not determined the product that was burning, but we believe it was mostly propane,” PES said.
Wholesale gasoline prices surged 3.7% Friday in New York on speculation that the PES outage might curtail regional fuel supplies.