EMF a health risk
Two reviews have concluded that electromagnetic fields from the power system may present a risk to public health.
For more than twenty years the question of whether electromagnetic fields (EMFs) from the power system contribute to health problems has been debated throughout the western world. For most of that time the fields of opinion have been polarised (if you’ll excuse the pun). On the one hand, members of the public and some independent scientists have maintained that there is evidence of risk, particularly from high voltage power lines. On the other hand, governments and electrical utilities have adopted the position that there is no conclusive proof of risk at athermal (non-heating) levels of exposure.
Indeed, most official reports have concluded that EMFs do not represent a health problem. In fact, a noteworthy report by a committee of the US National Institute of Environmental Health Science that did classify EMFs as “possibly carcinogenic” in 1998 was suppressed and only made public when it was leaked to the press.
Now, in a radical departure from tradition, two official bodies have admitted that EMFs may pose a health risk.
An expert scientific working group of the International Agency for Research on Cancer (IARC) has completed a literature review which concludes that magnetic fields from power sources are “possible carcinogens”.
The group, comprised of 21 scientists of diverse backgrounds and positions in the EMR debate, announced its unanimous decision on June 27 in Lyon, France.
In its statement to the press the committee wrote, “pooled analyses of data from a number of well-conducted studies show a fairly consistent statistical association between a doubling of risk of childhood leukaemia and power-frequency (50 or 60 Hz) residential ELF magnetic field strengths above 0.4 microTesla [4 milliGauss/mG], with an approximately twofold increase in risk. This is unlikely to be due to chance, but may be affected by selection bias. ...”
“Overall, ELF magnetic fields were evaluated as possibly carcinogenic to humans (Group 2B), based on the statistical association of higher-level residential ELF magnetic fields and increased risk for childhood leukemia.” This follows the release of a number of recent meta-analyses* (by Ahlbom, 2000; Greenland, 2000 and Doll, 2001) which found an increased risk of leukemia at just 3-4 mG.
The working group did not find evidence of risk from magnetic fields under 4 mG and it did not find that electric fields contributed to leukemia. “Evidence for excess cancer risks of all other kinds, in children and in adults, as a result of exposure to ELF electric and magnetic fields was considered inadequate.”
As in previous reviews, the IARC working group noted the disparity between the findings of epidemiological studies (such as those mentioned above) and laboratory studies. “Studies in experimental animals have not shown a consistent carcinogenic or co-carcinogenic effect of exposures to ELF magnetic fields.”
The Electricity Supply Authority of Australia (ESAA) responded to the announcement with a press release of its own on June 28 in which Managing Director, Keith Orchison, downplayed the significance of the IARC announcement. He said, “it is reassuring to note that IARC did not put power frequency magnetic fields in its higher risk categories of ‘known’ or ‘probably’ carcinogens and that they found that there was insufficient evidence to categorize magnetic fields even as a possible carcinogen for any other childhood cancer or any adult cancer, such as adult leukemias, brain cancer and breast cancer.”
More information about the IARC evaluation can be found at http://monographs.iarc.fr under “Agents most recently evaluated.”
A second review to connect EMF with health problems was conducted by the California Public Utilities Commission (PUC). Three scientists from the Department of Health Services (DHS), Dr Raymond Neutra, Dr Vincent DelPizzo and Dr Geraldine Lee, reviewed the literature on EMFs and assessed the likelihood of risk.
They concluded that it was more likely than not that EMFs caused childhood leukemia, adult brain cancer, amyotrophic lateral sclerosis (ALS) and miscarriages, possibly accounting for 40% of the latter. They also concluded that EMFs were up to 50% likely to cause female and male breast cancer, childhood brain cancer, suicide, Alzheimer’s disease, cardiac death and adult leukemia. They felt that it was unlikely, but not impossible, that EMF contributed to birth defects, neonatal deaths or cancer.
While recognising that leukemia is one of the most likely outcomes of high EMF exposure, the reviewers commented that it is a rare complaint, likely to affect only 4% of children. However, “if the same 4% were applied to the 11 conditions listed above [see below] that were not ‘very unlikely’ to be caused by EMFs, the numbers of attributable cases could be in the hundreds or thousands and comparable to the theoretical burden of ill health that has motivated other environmental regulation.”
In comparing EMF to chemical agents, the reviewers wrote, “With the exception of miscarriage, the added risk (if any) of even a highly EMF-exposed individual getting any of these rare diseases would be such that the vast majority of highly exposed individuals (95%-99.9%) would not get them. Calculations suggest that the fraction of all cases of these conditions for which EMF might be responsible would be very low. However, if EMFs really contribute to the cause of these conditions even these low individual risks and the low fractions of cases could be of concern to regulators. Indeed, when deemed real, theoretical risks smaller than these have triggered regulatory evaluation and sometimes, regulatory control of chemical agents.”
As in the IARC report, the DHS report recognised the disparity between animal and human studies. It comments that, even though carcinogens might be expected to cause cancer in animals, there are some human carcinogens “such as cigarette smoke, alcoholic beverages, benzene and arsenic” that were not shown to affect animals in laboratory studies “for many decades”.
The reviewers concluded that funding for further research “can be easily justified” and that further studies should investigate conditions with “shorter induction periods, such as spontaneous abortion, acute myocardial infarction, and suicide” rather than concentrating on conditions such as cancer which have a long latency period.Statement for the General Public
It is ‘more than 50% possible’ that EMFs at home or at work could cause a very small increased lifetime risk of childhood leukemia, adult brain cancer, and amyotrophic lateral sclerosis (ALS, Lou Gehrig’s Disease). As this phrase implies, there is a chance that EMFs have no effect at all.
It is ‘more than 50% possible’ that EMFs at home or at work could cause a 5-10% added risk of miscarriage, and again, as this phrase implies, there is a chance that EMFs have no effect at all.
It is ‘10-50% possible’ that residential or occupational EMFs could be responsible for a small increased lifetime risk of male breast cancer, childhood brain cancer, suicide, Alzheimer’s disease, or sudden cardiac death. As this phrase implies, there is a chance that EMFs have no effect at all.
It is ‘very unlikely (2-10% possible) but not impossible,’ that residential or occupational EMFs could be responsible for even a small fraction of birth defects, low birth weight, neonatal deaths, or cancer generally.
All of the three reviewers give a degree of confidence of at least ‘10-50% possible’ that residential or occupational EMFs could be responsible for a small increased lifetime risk of adult leukemia or female breast cancer, and one gave a degree of confidence that was higher.
* A meta-analysis is an analysis of the data of several studies.
The full text of the report can be found at www.dhs.ca.gov.
EMRAA News Sept 2001, Vol 6 No 3