SURPRISE, Ariz. (FOX 10) -- Three Peoria firefighters are still in the hospital after they were hurt by an explosion in Surprise.
The incident happened Friday night, as they responded to a HAZMAT call at an APS facility that stores solar energy in batteries.
The injured firefighters are being treated at the Arizona Burn Center, and one will be Monday night. Two others, however, will remain at the Burn Center for a long time, recovering from traumatic injuries. What exploded remains unknown, as of Monday.
"What they endured is tremendous. The force they went through is unimaginable," said Mike Selmar with Peoria Fire-Medical Department.
Selmar said it's a miracle that Peoria's top HAZMAT team is alive. Fire officials say their meters did initially detect a high level of explosives, but after the levels went down, the four attempted to enter the building. Investigators said as the door opened, a powerful explosion blasted the metal door off, and sent the four men about 100 feet.
"Just looking at that scene out there and seeing how far it took metal doors -- it shot them so far away -- look at their helmets on the ground with none of the padding, just empty shells because they were just ripped of their head," said Selmar.
Exactly what caused the explosion is under investigation. The firefighters suffered chemical burns.
"It was a combination of things, acids and bases and metabolites, but mostly acids," said Dr. Kevin Foster, Director of the Arizona Burn Center.
The burns are minor when compared to their traumatic injuries. Engineer Justin Lopez, a father of seven kids, suffered the worst, including a fractured skull and nose. Captain Hunter Clare has several broken bones in his ankles, shoulder, and ribs.
APS officials said the facility houses 32 lockers, or nodes. It has its own fire suppression equipment that releases a chemical which eliminates oxygen, preventing a fire from starting. Fire officials said the HAZMAT Team had no indication of danger, before the explosion.
The solar battery facility produces two megawatts of energy, enough to light 1,000 homes for an hour. APS conducting the investigation into the cause of the explosion.
APS has four solar battery facilities across the Valley. The one that exploded is a total loss, and the other three have been put out of service during the investigation.