One of my college professors was one of the early researchers involved in this.
This all started way back in the late 60s or early 70s. Some insurance guy noticed that people who live next to high voltage power lines don’t live as long as folks who don’t live next to high voltage power lines (insurance guys get paid big bucks to figure these kinds of things out, since they use this data to set their rates and therefore it directly effects their bottom line). For a long time, nobody but the insurance guys seemed to really care. Then, in 1977, a study got published that linked high voltage lines and childhood leukemia. This study was later discredited but by then the genie was out of the bottle. It set up the public opinion that power lines are dangerous.
In the 80s, things really got out of hand (thanks mostly to lawyers, IMHO). People were demanding to know what levels of fields were dangerous and what was safe, but at that point very few studies had been done on the subject. Some folks reached deep into their rectal area and pulled out some numbers, and before long folks were getting paid big bucks to walk around playgrounds and schools with field strength meters proclaiming which areas were safe and which areas weren’t.
Also during the 80s, cell phones started getting slightly smaller and lighter than your average concrete block and slightly less expensive than your typical Ford, and as they became more affordable, practical, and therefore popular, folks made the obvious connection that if fields from power lines could be bad then radio waves could be bad too.
Money started pouring in to research. By this time, there were already two very widely divided camps on the subject. You had the folks who thought power lines and cell phones and such were all perfectly safe, and you had the folks who were convinced they were all the spawn of Satan and were going to kill everyone and every living thing on the planet (ok, I might be exaggerating a bit). Both sides thought the other was wrong, and both were extremely heated in their arguments. I should also point out that at that time both sides had exactly the same scientific data to support their claims, which was basically none.
So now we fast forward a couple of decades. Tons and tons of research has been done on the subject. So far, no one has ever been able to prove a conclusive link between either power lines or cell phones and anything bad like cancer. Once in a while a study will find some sort of link, but then follow-up studies fail to find the same link. You might think that, given the extreme emotions of both sides of the argument, that many of these studies are biased (oh, gee, the study funded by the Coalition to Ban All Evil Cell Phones found that they cause cancer, gee what a surprise) but actually most of the studies are done by reputable scientists and their methods are valid. This is just what you get sometimes. You do a study and sometimes you find something, but sometimes it is a false positive. You publish what you find, and see if follow-up studies find the same thing. That’s the way science works.
The problem is that “CELL PHONES ARE KILLING US” makes a great front page story, while “Nope, we didn’t find anything” is much less exciting and doesn’t get the same front page treatment. This means that the initial study that finds a possible link gets a huge amount of press, and the follow-up studies that don’t find anything hardly get mentioned in the news at all. This leads a lot of folks to think that there is a lot more proof of bad things related to power lines and cell phones than there really is.
The bottom line is that after several decades of research, there has yet to be a single study that has held up to peer review and follow-up studies that has conclusively proven a link between power lines or cell phones and anything bad. After several decades and billions and billions of dollars worth of testing, it’s starting to look like absence of evidence really does mean evidence of absence.
Because you still get the occasional false positives showing up in the news, folks get the impression that this is still an undecided issue, but if there was really something to it all, you’d think that they would have found it by now.
By the way, the OP’s quote about building-wide 12 volt 15 amp circuits made me giggle. Good luck getting that to work. There are reasons Edison lost, you know. Those guys at Google should stick to software.
ETA: By the way, we still don’t know why folks who live next to power lines live shorter lives. One of my college professor’s theories was that folks who choose to live healthier lifestyles simply choose not to live next to power lines.