I've read some materials about eye's light sensitive cells degradation in X-Ray and Gamma. But MMW is completely different band.
It is close to thermal IR band.
So even without Heavy metals say from ingested sources out bodies if exposed to short but high powered emf feilds might suffer tissue damage and even failure ?? This is being reported already with lower levels of emf exposure !
Just don't get me wrong or blaming in something. We need the numbers.
"Low-level" term needs comparison. For some case "low-level" means 1W. For other, like comparison with MW oven (750W) "lower level" could mean 100W which is ultimately huge power for domestic wireless, but less than 10% level for oven.
Remember the Einstein, BRO! :)