The view of the HPA
In a major review of the evidence for a possible association between exposure to power-frequency electric and magnetic fields and the incidence of cancer published in March 2001, the NRPB Advisory Group on Non-Ionising Radiation concluded:
“Laboratory experiments have provided no good evidence that extremely low frequency electromagnetic fields are capable of producing cancer, nor do human epidemiological studies suggest that they cause cancer in general. There is, however, some epidemiological evidence that prolonged exposure to higher levels of power frequency magnetic fields is associated with a small risk of leukaemia in children. In practice, such levels of exposure are seldom encountered by the general public in the UK. In the absence of clear evidence of a carcinogenic effect in adults, or of a plausible explanation from experiments on animals or isolated cells, the epidemiological evidence is currently not strong enough to justify a firm conclusion that such fields cause leukaemia in children. Unless, however, further research indicates that the finding is due to chance or some currently unrecognised artefact, the possibility remains that intense and prolonged exposures to magnetic fields can increase the risk of leukaemia in children.”
In its new advice on exposure limits in 2004, the NRPB stated:
“In the view of NRPB, the epidemiological evidence that time-weighted average exposure to power frequency magnetic fields above 0.4 µT is associated with a small absolute raised risk of leukaemia in children is, at present, an observation for which there is no sound scientific explanation. There is no clear evidence of a carcinogenic effect of ELF EMFs in adults and no plausible biological explanation of the association that can be obtained from experiments with animals or from cellular and molecular studies. Alternative explanations for this epidemiological association are possible: for example, potential bias in the selection of control children with whom leukaemia cases were in some studies and chance variations resulting from small numbers of individuals affected. Thus any judgements developed on the assumption that the association is causal would be subject to a very high level of uncertainty.”
More on HPA.
The view of IARC
The International Agency for Research on Cancer (IARC) is an agency of the World Health Organisation. Its Unit of Carcinogen Identification and Evaluation has, since 1972, periodically published Monographs which assess the evidence that various agents are carcinogenic and classify the agents accordingly. In June 2001, a Working Group met to consider static and extremely-low-frequency electric and magnetic fields. The complete results have been published as Monograph number 80. Power-frequency magnetic fields were classified as “possibly carcinogenic”, on the basis of “limited” evidence from humans concerning childhood leukaemia, “inadequate” evidence from humans concerning all other cancer types, and “inadequate” evidence from animals. Power-frequency electric fields were judged “not classifiable” on the basis of “inadequate” evidence from both humans and animals. More on IARC
The view of ICNIRP
A major review on epidemiology published by ICNIRP in 2001 concluded:
“Following the original report by Wertheimer and Leeper linking the three most common forms of childhood cancer with a proxy measure of residential EMF (wire codes), more than 18 studies in nine countries have shown no convincing evidence of a relationship between childhood leukaemia and residential EMF exposures among children with estimated exposure levels under 0.2 µT. A 2-fold increase in relative risk of childhood leukaemia, confined to a very tiny fraction of children (estimated as 0.8% in one large pooled analysis) with residential EMF exposures ≥0.4 µT, is difficult to interpret in the absence of a known biological mechanism or reproducible experimental support of carcinogenesis. There is also some evidence to suggest that selection bias may account for some of the increase in risk among the proportion of children with high residential EMF exposure.” More on ICNIRP
The view of WHO
The WHO Environmental Health Criteria Monograph published in 2007 concluded:
"The IARC classification was heavily influenced by the associations observed in epidemiological studies on childhood leukaemia. The classification of this evidence as limited does not change with the addition of two childhood leukaemia studies published after 2002. Since the publication of the IARC monograph the evidence for other childhood cancers remains inadequate.
Overall conclusion
New human, animal and in vitro studies, published since the 2002 IARC monograph, do not change the overall classification of ELF magnetic fields as a possible human carcinogen."
More on the WHO Monograph