A tripped transformer is being blamed for a foamy mess that billowed out of a Center City Philadelphia substation over the weekend and onto streets and yards.
Despite residents in the area hearing "popping" sounds there was no explosion Saturday afternoon at the PECO substation along S. Juniper Street near Lombard Street, said PECO spokesman Ben Armstrong Monday. [[404498065, C]]
"There was this loud bang noise and I was like, 'Oh boy. I hope everything is OK," said witness Christian Bygott.
A circuit breaker in one of two large transformers in the red-brick facility surrounded by row homes and apartments went offline. The tripping of that breaker caused the "pop" and a flash that people mistook for a possible explosion around 1 p.m., said PECO.
Once the system tripped, the building began to pump out a white foam as the station's fire suppression system automatically activated, pouring foam out of the building – some wound up in Bygott's backyard.
"[It was] sort of like that old movie, 'The Blob' except it was its really super slow cousin," he said. [[404522815, C]]
The foam also pushed out of the roof of the empty substation. At one point the foam on the street was around 6-feet high.
The foam suppression system is set to automatically trigger when something goes wrong with the transformers, said PECO. Once it triggers, the foam will continue to pour out until the system is manually turned off or the foam – intended to be at least enough to coat the entire building – runs out, said PECO. It wasn’t clear, which happened in this case.
Around 17 units, including a Hazmat Task Force, were sent to the foam-flooded street. The foam is similar to the substance used in washing machines and is non-hazardous, according to officials. They also say it has no detrimental effects on the environment. Crews washed away much of the foam.
The utility continued to internally investigate the incident Monday, which temporarily knocked out power to about 2,500 customers and left around 650 customers without power for around three hours. Armstrong told NBC10 that PECO was looking into the chronology of events that led up to the incident and what triggered the fire suppression system.
PECO had not reached out to law enforcement, they said. The FBI told NBC10 that they were not investigating the issue and that it appeared to be an electrical issue.
Luckily no one was inside the building at the time and no one was hurt.