Of course electro-magnetic fields (EMFs) are bad for you. I studied this about 7 years ago, and it periodically enters the news. This time, it re-entered the news because a group of protestors planted 1200 fluorescent light tubes (the kind used in offices) under power lines somewhere near Derby. And the bulbs lit up despite not being connected to any power source - it was the electro-magnetic field from the powerlines. If a person went nearer to a tube it glowed brighter. This is because electricty conducts better through humans than it does through air.
EMFs are created by all electrical devices or electrical wires. This is because electrons 'escape' from their primary conduit. It's like Niagara Falls - while most of the water is part of the current, some of it escapes in the air in spray and water vapour. So even a small electrical wire has a field around it.
Anyway, there are two dangers from EMFs.
The one commonly accepted by scientists is that because the field is negatively charged it attracts Radon gas particles, which are positively charged. Radon gas is the nucleus of a Helium molecule, and is commonly referred to as ionising alpha radiation. When you breathe this in it 'sticks' in your lungs and causes cell damage. This is thought to be a cause of leukaemia or lung cancer. Radon gas is naturally present in the air at low levels thought not be any more harmful than any other kind of radiation we encounter everyday. Although some areas have abnormally high levels - for example Cornwall - which has more of a particular kind of rock in the ground (dunno what kind).
The other danger, and the one everyone wants to deny, is whether EMFs cause any direct damage to the body. Mobile phone radiation has a similar wavelength and frequency, so obviously it's in Corporate UK's interest to buy enough studies to get it sufficiently denied. EMFs consist of free electrons moving near to the speed of light. This kind of radiation is known as ionising beta radiation. Electrons are small enough to destroy DNA cells (as well as every other kind of cell in your body). In theory, they can't travel through metal or bone - however in a strong enough field, such as one underneath a powerline, your skull won't be much use.
Everything in life destroys your DNA, even in the stone age before electricty it was the case, it's just a question of how much. Today, with computers, TVs, mobile phones, travelling in aircraft we are inside electromagnetic fields all of the time. Thankfully they aren't anywhere near the kind of levels underneath a powerline.
But there are plenty things you can do to reduce your exposure. Don't sleep with electrical devices turned on in the same room - so don't recharge your mobile phone in the same room while you're asleep (and turn it off), don't leave your TV on standby mode while you're asleep (it uses up 80% of the power as when it's turned on), get a battery powered alarm clock, try not to use a computer in your bedroom.
Most big electrical goods that produce high levels of EMFs are made out of metal - there is a reason for this - it can stop a certain amount of the field from getting through the casing. Computers are quite bad when it comes to EMFs, especially the power supply. Have you seen those fancy decorative cases? Some are made out of plastic and glass - this is useless to shield against radiation. You might as well not bother have a case at all. The other big thing is the monitor - with a conventional monitor you are sitting staring directly into an electron gun. So try not to sit too close to it. The effects are noticable - bad skin - spots.
Aircraft are quite bad too - the steel body isn't as good as 30,000 feet of atmosphere for protecting against cosmic radiation. A 30 minute flight from London to Paris is equivalent to getting an X-ray. God only knows what my liking of travelling to Australia & New Zealand complete with 26-hour flights will do to me.
The good news is that the strength of a field reduces inversely proportional to distance (1/x type thing). Sitting 6 feet from a TV and the field is probably negligble, same for a microwave. Try to sit 2-3 feet away from a computer, and make sure the tower isn't right next to your legs.
Even if you manage all that, there's still the DNA-damaging free radicals you get from processed food, pesticides they spray on fruit, and pollution. We just have to accept that our DNA cells will become damaged or mutated by radiation as a course of life.
As for legal action against the power companies, I think they should be funding research into safer ways of transporting electricity.
