Electric and magnetic fields (EMF) are areas of energy around power lines, electrical wiring and appliances. Electric fields are more likely to be shielded by walls or other objects, while magnetic fields are more likely to penetrate the body. For this reason, magnetic fields are usually studied in relation to cancer risk. Power lines and household appliances, such as electric blankets, televisions, computers, hair dryers, and electric shavers, emit extremely low frequency magnetic fields. Most electrical appliances need to be turned on to emit magnetic fields, and the strength of the magnetic field decreases with increased distance from the source.
In 2002, the International Agency for Research on Cancer (IARC) reviewed the available evidence in relation to extremely low frequency magnetic fields and cancer. IARC is a part of the World Health Organization which convenes international expert working groups to evaluate the evidence of the carcinogenicity (cancer causing properties) of specific exposures. Based on the weak association between extremely low frequency magnetic fields and childhood leukaemia found in epidemiological studies, inadequate human data for all other cancers, and inadequate animal data, IARC classified extremely low frequency magnetic fields as a possible human carcinogen.
In 2007, the World Health Organization (WHO) reviewed the evidence, focusing on studies published after the IARC review. The WHO concluded that the results of relevant research published since 2002 did not warrant a change in the classification of extremely low frequency magnetic fields as a possible human carcinogen.
Most recently, in February 2014, research by the Childhood Cancer Research Group at the University of Oxford was published in the British Journal of Cancer. The study analysed data from the National Registry of Childhood Tumours, including 16,500 children who developed leukaemia in Britain between 1962 and 2008. The researchers found that although there was a higher risk of developing leukaemia among those who lived within 600 metres of power lines in the 1960s and 1970s, the risk declined over time and from the 1980s onwards, there has been no increased leukaemia risk among those living near power lines. The researchers concluded that children who live near overhead power lines do not have an increased risk of developing leukaemia; but the reasons for the declined risk over time are not clear, and continued research is required to understand the historical patterns.
It is unlikely that household electrical appliances increase your risk of cancer because the amount of magnetic field they emit is limited. However, if you are worried, simple steps you can take to reduce exposure include:
- Turn off electrical appliances when not in use;
- Use your electric blanket to warm up your bed and turn it off before you get in;
- Sit at least 50cm away from your TV screen; and
- Don’t have your bed against a wall that has an electric hot water service on the other side.
The amount of magnetic field emitted by powerlines decreases the further away you are. Once you are 200 metres away, you are out of range. If you are worried about powerlines in your neighbourhood, you could measure the magnetic field in your house. The Australian Radiation Protection and Nuclear Safety Agency(ARPANSA) has magnetic field meters for hire which can be used to measure exposure. The cost is $39.85 for use over a few days, plus $9.85 postage to anywhere in Australia. The hire agreement can be downloaded from the website or you can phone ARPANSA on (02) 9541 8333.
If you find a high magnetic field in parts of your house, one option to consider rather than the somewhat drastic step of moving house is to sleep in a part of the house that is as far away as possible from the source to minimise exposure.
For more information visit the ARPANSA website.