There isn't any evidence that living near power lines increases adults' risk of getting cancer. But, some studies suggest that children living very close to overhead power lines may be at greater risk of developing leukaemia. There is no evidence for an increased risk of developing any other type of cancer.
Many studies have looked at whether there is an increased cancer risk from exposure to the extremely low frequency (ELF) electromagnetic fields produced by power lines. The results of these studies are inconsistent. But, it is now thought that children who are exposed to high levels of ELF electromagnetic fields over a long period of time may have their risk of developing leukaemia doubled. The risk of a child developing leukaemia by the age of 15 is 1 in 1400. If this risk was doubled it would mean there was a 1 in 700 risk of a child developing a leukaemia by the age of 15.
Magnetic fields are measured in tesla (T). In most homes the background levels of magnetic fields are between 0.01 and 0.2 microT. Studies have suggested that there is an increased risk of leukaemia in children who are exposed to levels above 0.4 microT over long periods of time.
Most children (over 99%) live in homes with background levels of 0.2microT or less. But, the levels are higher in homes directly beneath or very close by power lines. It is thought that houses within about 200m of high voltage overhead power lines may be exposed to fields greater than 0.4microT.
This sounds quite frightening but most children living in homes close to power lines will never develop leukaemia. It is estimated that if power lines do increase the risk of leukaemia in children they may cause one extra case of childhood leukaemia in the UK per year.
At the moment there aren't any regulations about how close power lines can be sited to houses. But, if you are worried about the magnetic fields in your house you can contact the Health Protection Agency for advice.
References:
- SAGE: Precautionary approaches to ELF Electromagnetic Fields. 2007
- ELF Electromagnetic Fields And the risk of cancer. NRPB 12(1) 2001