AT&T’s project AirGig, where 5G millimeter wave Internet signals are carried along power lines, is in the test phases right now. If AT&T launches this, it means that if you work or live anywhere near a power line integrated with AT&T 5G, you will be exposed to the 5G mm wave radiation constantly. So it‘s not just the 5G small cells placed every few houses apart that would be radiating the mm wave radiation, but the entire power line!!!
Delivering Internet via power lines was tried in the past, but there were many problems with reliability. However, AT&T says the same reliability problems won’t exist now. http://www.govtech.com/internet/Project-AirGig-Aims-to-Deliver-Internet-Over-Power-Lines.html