While I personally have doubts about this microwave "cracked glass" concept bein...

While I personally have doubts about this microwave "cracked glass" concept being implicated in cancer--if anything I'd be more concerned about the effects of eating stuff that came out of the microwave for various reasons--we know that "non-ionizing radiation" is not the same thing as "can't cause cancer": it only means it can't directly damage DNA, but has been shown to be able to re-fold DNA or indirectly lead to oxidative stress via localized vibration and heat.