SANTA ANA (AP) — An explosion Tuesday in the boiler room of a Southern California high school gymnasium briefly lifted up the building's roof, damaging the structure but causing no major injuries.
The blast around 7:30 a.m. at Valley High School in Santa Ana was in a girls' locker room and happened before classes began, although some students were arriving on campus, authorities said.
Security camera video broadcast by KABC-TV showed the fiery explosion lift up the building's roof as at least a half-dozen people ran from the area. The blast also blew doors off their hinges and sent smoke billowing from the building, which houses the gym, locker rooms and offices.
No students or staff were inside, said Deidra Powell, a spokeswoman for the Santa Ana Unified School District.
Seven students suffered minor injuries such as anxiety, ringing in their ears and headaches, Powell said. Four students sitting on a park bench with their backs to the boiler room were taken to hospital for their injuries.
"They were more just shook up," said Orange County Fire Authority spokesman Capt. Jon Muir.
Muir said the explosions ripped off a door and blew it about 75 feet, tore at least three other doors from their hinges, knocked down ceiling tiles, and lifted the roof 4 to 5 inches off its load-bearing wall.
"It was a very big deal," he said. "It's fortunate there were no kids inside. It was a big explosion."
Fire investigators believe they may be looking at a mechanical or gas-related problem since the force of the blast went up and not out, Muir said.
Most of the damage was limited to the area between the girls' and boys' locker rooms, Powell said.
A bomb squad also was called in as a precaution.
The campus was reopened around 8:30 a.m. and students attended regular classes, although some courses held near the blast site were moved to a different location.
"It is the end of the school year, and it's not going to cause any major disruption to things that were planned," Powell said.
Seniors were not on campus because they were preparing elsewhere for graduation ceremonies. The last day of school is Thursday.
The school, which opened in 1959, has about 1,800 students.