We do know electromagnetic fields are not healthy at high doses. Those of us raised before flat screen televisions can remember being told not to sit too close to the screen, even if our parents could not explain what exactly the danger was the danger was known.
The thing is that we are surrounded by electromagnetic fields and in fact have our own fields individually.
Our earth is also a source of electromagnetism.
We can see this magnetism in the Aurora Borealis.
Auroras appear during geomagnetic storms--that is, when Earth's magnetic field is vibrating in response to a solar wind gust. Such gusts pose no danger to people on the ground because our magnetic field forms a bubble around Earth called the magnetosphere, which protects us. The magnetosphere is filled with electrons and protons. "When a solar wind gust hits the magnetosphere, the impact knocks loose some of those trapped particles," explains space physicist Tony Lui of Johns Hopkins University. "They rain down on Earth's atmosphere and cause the air to glow where they hit--like the picture tube of a color TV."
To see how EMF is all around us watch this five minute clip. You will never look at your toaster the same way again.
Notice at the 3:10 point they say they come towards our bodies and then bend away. The reason they come away is we too have our own electromagnetic fields. It takes exceptionally powerful fields to counteract our own individual charges. Large radar and cell phone towers are fenced off so they do not damage us with these strong fields.
Notice this fence is not designed to keep people at a great distance. And the cell tower output is much larger than the largest generators a windmill could support. I would not recommend picnicking in a windmill farm, although I have no studies to support that recommendation. But having a wind farm a mile away will not cause any electromagnetic changes at that distance.
There are measuring devices to determine EMF output.
There is no real threat from EMF as long as you stay away from cordoned areas.
Unless it is used in the wrong hands.