non-ionizing means mostly harmless, but there is no guarantee. Proteins come in lots of shapes and sizes, and non-ionizing radiation can still resonate.

They can activate melanocytic nevus (moles) on the skin though.

And their effectiveness is, questionable (Germany reports 54% false positives, TSA reports handguns being concealed successfully in underwear, etc.)

Microwave ovens also produce non-ionizing radiation so I imagine that they would be safe to place one's full body inside as well.