RF energy in itself can be a hazard. Radiation Hazard (RADHAZ) is typically mitigated by separation from the emitter source and these are the typical warning signs posted. There are three classes of RADHAZ:
HERP is the danger to personnel from the absorption of electromagnetic energy by the human body. Personnel hazards are associated with the absorption of RF energy above certain power levels in certain frequency bands for certain lengths of time. Its all spelled out in the DoD Instruction noted. DoD Instruction 6055.11 defines the allowable amounts in terms of how long personnel may be exposed to RF fields of particular intensities at particular frequencies. You may have seen warning signs such as this one posted aboard ships.
HERO refers to the susceptibility of electro-explosive devices (EEDs) to RF energy. These EEDs or EIDs are used to detonate explosives, launch ejection seats, cut tow cables, etc. Modern communication and radar transmitters can produce high electromagnetic environments that are potentially hazardous to ordnance. These environments can cause premature actuation of the following sensitive, electrically initiated devices including: Explosive Elements Known As EEDs
HERO is especially important today because of the increased use of Joint or International military operations. The Navy has a very robust HERO program but that may not be the case with the Army, Air Force or even the Special Forces. When they bring their ordnance aboard ship (and the Special Forces has all kinds of special things that go BOOM), there may have to be severe operating restriction imposed if the HERO status of this ordnance isn't well known.