The Mercola article doesn't really mention this, but most studies of harmful EMF (also called Electromotive Force or voltage) are done at either 50 or 60 hz. Frequencies above and below these values, aren't harmful when used in conventional ways, but for some "synchronistic" reason, these 2 frequencies are used in virtually ALL power generating plants around the world!
I'm not a Conspiracy kind of guy, but it's almost as if someone planned to generate ill health effects to go along with electrical power generation, when these "standards" were decided long ago.
Most people can take a LOT of spurious radiation ( Cell Phone s, microwaves, TV/Computer screens, etc.) but there are a few that can't even bear walking into (say) a retail store that uses florescent lights. Some poor souls have had to line their homes with copper grid barriers (faraday cages), and find curtain material that shields all electric "noise" out of their tiny living spaces.