ATF joins probe of LA blast that injured 12 firefighters

LOS ANGELES (AP) Investigators are combing the wreckage of a fire and explosion at a downtown Los Angeles hash oil manufacturer as six burned firefighters remained in the hospital.

The Bureau of Alcohol, Tobacco, Firearms and Explosives on Monday is sending in special agents to help reconstruct the scene, identify where the fire started and determine a cause.

Firefighters were at the nondescript commercial building late Saturday afternoon when there was a thunderous explosion that sent them scrambling through searing flames to get out of the building. 

Twelve  were injured. All are expected to survive.