Mike,
The experts in the disposal of explosive ordnance is the military (ARMY, NAVY, AIR FORCE and MARINES), with the HQ at Indianhead Naval Station in Maryland. The Indianhead facility is a multi-service school providing education and training to all US services. The individual military bases or commands will out source disposal contracts to get rid on old or defective ordnance.
There are a few other agencies that provide education, but the military is the recognized experts in the field.