Nov 30, 2012 2:28 PM by Sarah Sanchez
CASA GRANDE - Authorities are investigating an explosion at the Social Security Administration building in Casa Grande Friday morning.
It happened at the back entrance of the office just before 8:30 a.m., according to Barbara Rice, Casa Grande Fire Marshal.
No one was injured, Rice said.
The building was blackened around the door, but the damage was not extensive, according to Rice.
The federal Bureau of Alcohol, Tobacco, Firearms and Explosives has investigators at the scene.
Sources tell News 4 Tucson that a large amount of accelerant was used in the explosion.
KVOA News 4 Tucson also has a crew at the scene.
Stay tuned to News 4 Tucson on your television, computer, and mobile device for updates throughout the day.