In this still image taken from a security camera show students at Santa Ana High School reacting during a explosion in the boiler room Tuesday, June 11, 2013 in Santa Ana, Calif. The ex

 

              In this still image taken from a security camera show students at Santa Ana High School reacting during a explosion in the boiler room Tuesday, June 11, 2013 in Santa Ana, Calif. The ex
In this still image taken from a security camera show students at Santa Ana High School reacting during a explosion in the boiler room Tuesday, June 11, 2013 in Santa Ana, Calif. The explosion happened near the school's gym and it caused significant structural damage to the building but no injuries. (AP Photo)