Explosion rattles high school

SANTA ANA, California (AP):

Seven students sustained minor injuries from an explosion in the boiler room of a Southern California high school gymnasium that briefly lifted the roof of the building.

Orange County Fire Authority spokesman Jon Muir says four students were taken to a hospital Tuesday for minor injuries, ranging from ringing in their ears to anxiety.

The explosion occurred around 7:30 a.m. at Valley High School in Santa Ana before classes began.

Security camera video broadcast by KABC-TV showed the explosion lift the building's roof up as at least a half-dozen people ran from the area.

The cause of the blast is under investigation.