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How does this affect me?

 

Does Residential Exposure to Power Frequency Electromagnetic Fields Cause Cancer?


The residential epidemiology has suggested that there may be a small risk related to leukaemia in children and young persons and in particular to those exposed at levels of average domestic exposure to magnetic fields at or above 0.4 µT (400 nT). However the evidence is inconclusive. The epidemiological association may be due to chance, confounding factors or some unrecognised artefact related to the way the data have been collected. The review of experimental studies gives no clear support for a causal relationship between exposure to ELF EMF and cancer. AGNIR also concluded that there is no reason to believe that residential exposure to EMF is involved in the development of cancer in adults, and in particular of leukaemia or brain cancer.


What Causes Higher Exposures in Homes and How Can They Be Identified?

There are many potential sources that could contribute to higher exposure in homes, such as electrical appliances, household wiring, power lines and the electricity supply. It is estimated that about 0.5% of the UK population have average residential exposures at or above 0.4 µT. The results of the UK Childhood Cancer Study (UKCCS) suggest that not all of the homes in the UK in which exposures were high were associated with obvious features of the electricity supply system such as high voltage power lines. There are a number of possible explanations for this and it is the HPA Board's view that there is a need to better understand the exposure factors that have lead to the epidemiological association

 

Am I Putting My Child at Risk of Cancer by Living in a High Exposure House Beneath a Power Line?


The overall leukaemia risk in children is about 1 in 1400 up to age 15 years. Doubling the risk as suggested by the epidemiological evidence gives 1 in 700 (to age 15 years) for the 0.5% of children who are exposed on average at 0.4 µT and above. However it is important to recognise the uncertainty when interpreting the epidemiology, and that the review of experimental studies gives no clear support for a causal relationship between exposure to ELF fields and cancer.

What Other Causes of Childhood Cancer Are Being Investigated?


The weight of evidence does not support a major role for electromagnetic fields in causing cancer. However the causes of childhood cancer are poorly understood. Ionising radiation, some cancer chemotherapy agents, viruses and genetic factors are each understood to be the cause of a small proportion of cases, but for most cases the cause is uncertain. The UKCCS is currently examining a number of the factors which might influence the disease and these include exposure to ionising radiation (natural or man-made), the use of drugs and hazardous chemicals, and abnormal responses to infection. The UKCCS, based on nearly 4000 cases of childhood cancer, is the world's largest case- control study on the causes of childhood cancer.

At What Distances from a Power Line Am I Likely to Encounter Magnetic Field Levels of 0.4 µT and Above?


In relation to power lines the magnetic field encountered in any particular circumstances will relate mainly to the circuit current, the line geometry and the distance from the line. In most situations for high voltage power lines at 132 kV and above, average field levels of 0.4 µT or above might be encountered at ground level at distances of up to several tens of metres away from the line. Lower voltage power lines at 11 kV to 66 kV tend to have smaller currents and conductor separations than the higher voltage lines, and levels of 0.4 µT or above might occur at closer distances to the lines, typically up to a few tens of metres. The distances will usually be much less for high voltage underground cables. For local area substations the distances typically will be no more than a few metres.

Is the Risk Larger If My Child's Exposure Is Above 0.4 µT?


It is unlikely that your child's average exposure will be 0.4 µT or greater. However, the epidemiology covered by AGNIR suggests that if there were an effect of magnetic fields this is the level above which the estimated relative risk doubles. In the most recent studies reviewed the nature of any change in risk with increasing exposure is unclear.

What about Exposures at Lower ELF EMF Exposures?

 

The UK Childhood Cancer Study, representing the world's largest case-control study on the causes of childhood cancer, with much the largest number of direct measurements of exposure, found no evidence of an increase in risk at average exposure levels below 0.4 µT. In the EMF part of the UKCCS there were 2226 case-control pairs.

 

Is There a Cancer Risk for Adults Living Close to Power Lines?

There have been fewer residential studies for adults than for children. Those that have been carried out have mostly examined leukaemia and brain cancer although other cancers have been studied. AGNIR concludes that there is no reason to believe that residential exposure to EMF is involved in the development of cancer in adults, and in particular of leukaemia or brain cancer.

 

Is There a Cancer Risk from Occupational Exposure to Power Frequency EMF?

Although recently published studies are in the main methodologically sound and some have considerable statistical power, causal relationships between occupational EMF exposure and cancer incidence are not established.

 

Can I Get Measurements Made of the Power Frequency Magnetic Field Levels in My Home?

The Energy Networks Association supports an EMF unit and customer information line as an initial point of call for all EMF enquiries. Under some circumstances the appropriate electricity company may be able to visit your home to make measurements of fields.

 

What Will the Measurements Tell Me?

The measurements can be compared directly with the existing exposure guidelines. However they cannot be used to assess cancer risk or any other adverse health risk because no causal relationship has been demonstrated. It is also important to realise that the value used in the epidemiological studies is obtained from an assessment of exposure averaged over time. Spot measurements will not account for the variation in exposure due to time spent in other parts of the home and the changing currents flowing in supply and distribution circuits.

 

What Can Be Done to Reduce Exposure in Homes?


NRPB, now the Radiation Protection Division (RPD) of the HPA, published a comprehensive review of the science related to developing its advice on exposure guidelines. The advice noted the association between EMFs and childhood leukaemia and recommended that government should consider further precautionary measures in respect of exposure of people to EMFs. Reducing exposure in homes is one such precautionary measure which is being discussed by a group called SAGE (Stakeholder Advisory Group on ELF EMFs) that has been set up by the government to look at this issue. More information is available on the SAGE website at www.sagedialogue.org.uk. Individual circumstances in homes can be quite different. Avoiding the use of certain appliances may reduce exposure slightly and studies suggest that appliance exposure generally accounts for a small proportion of average exposure. However, most of the epidemiological studies attempt to capture background exposures and these arise from the local electricity supply and distribution circuits, and In these circumstances it is not possible to take simple measures to reduce exposures.

HPA RPD has completed a study which identified the main sources of elevated exposure in UK homes. The study was published in 2005 as an HPA-RPD report entitled Investigation and Identification of Sources of Residential Magnetic Field Exposures inthe United Kingdom Childhood Cancer Study (UKCCS).

I Live Near to a Power Line and am Worried about the Possible Health Consequences of Exposure to ELF EMF. What Can I Do?

 

This question of reducing exposure near to power lines is being considered by SAGE (Stakeholder Advisory Group on ELF EMFs) which has been set up to explore the implications for a precautionary approach to power frequency electric and magnetic fields and make practical recommendations. The SAGE website can be found at www.rkpartnership.co.uk [outside link].

 

Should Houses be Built Near to Power Lines?


NRPB, in its advice on exposure guidelines, noted the association between EMFs and childhood leukaemia and recommended that government should consider further precautionary measures in respect of exposure of people to EMFs. The scientific evidence considered in the advice on exposure guidelines does not provide a basis to stop building houses near to power lines, other than as a precautionary measure. The question of building houses near to power lines is being addressed by SAGE (Stakeholder Advisory Group on ELF EMFs) . The SAGE website can be found at www.rkpartnership.co.uk [outside link].


Last reviewed: 8 June 2010