WASHINGTON -- No clear, convincing evidence exists to show that residential exposures to electric and magnetic fields (EMFs) are a threat to human health, a committee of the National Research Council has concluded in a new report.* After examining more than 500 studies spanning 17 years of research, the committee said there is no conclusive evidence that electromagnetic fields play a role in the development of cancer, reproductive and developmental abnormalities, or learning and behavioral problems.
"The findings to date do not support claims that electromagnetic fields are harmful to a person's health," said committee chair Charles F. Stevens, investigator, Howard Hughes Medical Institute, and professor, Salk Institute, La Jolla, Calif. "Research has not shown in any convincing way that electromagnetic fields common in homes can cause health problems, and extensive laboratory tests have not shown that EMFs can damage the cell in a way that is harmful to human health."
Concern about the health effects from EMFs arose in 1979 when researchers showed that children living close to high concentrations of certain types of electrical wires were 1.5 times more likely to develop leukemia. Because it is difficult, time-consuming, and expensive to measure electric fields in a home over a long period of time, researchers relied on a substitute to estimate the levels of electromagnetic fields to which residents may have been exposed. Using factors such as the size of wires going past the home and distance between the home and power lines, researchers estimated the fields inside.
The Research Council committee's report says that studies in the aggregate show a weak but statistically significant correlation between the incidence of childhood leukemia, which is rare, and wire configurations. It never has been demonstrated that this apparent association was caused by exposure to electromagnetic fields, however. Outside wiring correlates poorly with measurements of actual fields inside the home, in that it accounts for only a fraction of the fields inside. Scientists have tried unsuccessfully to link leukemia to EMFs by measuring fields inside of homes of children who had the disease. The results "have been inconsistent and contradictory and do not constitute reliable evidence of an association," the report says.
The weak link shown between proximity to power lines and childhood leukemia may be the result of factors other than magnetic fields that are common to houses with the types of external wiring identified with the disease. These possible factors include a home's proximity to high traffic density, local air quality, and construction features of older homes that fall into this category, the committee said.
Cells, Tissues Unaffected
To try to explain and expand on the knowledge gained from early epidemiologic studies, researchers have studied the potential effects of EMFs on individual human cells or tissues, and on animals. To date, they have found no evidence to show that EMFs can alter the functions of cells at levels of exposure common in residential settings. Only at levels between 1,000 and 100,000 times stronger than residential fields have cells shown any reaction at all to EMF exposure, and even these changes -- mainly in the chemical signals that cells send to each other -- are not a clear indication of the potential for adverse health effects. In fact, exposure may actually help the body in some subtle ways, for example by speeding up the healing process after a bone is broken.
Most important, there has been no case in which even tremendously high exposure to EMFs has been shown to affect the DNA of the cell, damage to which is believed to be essential for the initiation of cancer. Similarly, no animal experiments have shown that EMFs, even at high doses, can act as a direct carcinogen or can affect reproduction, development, or behavior in animals.
Electromagnetic fields are generated by wires or electrically powered devices, and dissipate quickly, like light. When assessing potential impact of EMFs on health, scientists focus mainly on magnetic fields produced by power lines and electric appliances, which can pass through the body and generate small electric currents. Unlike magnetic fields, electric fields themselves lose most of their strength when they pass through metal, wood, or even skin. In fact, the strongest of either fields that the body encounters are the electric currents produced naturally when the heart beats, or as nerves and muscles function, the report says.
The committee focused on the health studies of low-frequency electric and magnetic fields common in homes. Sources of exposure include transmission and distribution lines and electric appliances, including shavers, hair dryers, video display terminals, and electric blankets. The committee did not study in detail occupational exposures, such as those experienced by electrical workers close to higher-frequency power lines.
New research is needed to answer some of the questions that linger after nearly two decades of intensive research, the committee said. Most compelling is the need to pinpoint the unexplained factor or factors causing a small increase in childhood leukemia in houses close to power lines. The precise factors that are related to an increased number of childhood leukemia cases need to be identified.
The committee also called for more research into the relationship between high exposures to EMFs and breast cancer in animals already exposed to other carcinogens, and on reasons why electromagnetic fields seem to affect the levels of the hormone melatonin in animals, an effect not reproduced in humans.
This congressionally requested study by the National Research Council was sponsored by the U.S. Department of Energy. The National Research Council is the principal operating arm of the National Academy of Sciences and the National Academy of Engineering. It is a private, non-profit institution that provides science and technology advice under a congressional charter.
Full Text of Press Release
Executive Summary of Report
Text of Report.
NAS Report Confirms Need For EMF research,
Frederick, MD, October 31, 1996 -- The president of the Bioelectromagnetics Society, Dr. Richard Luben, today welcomed the release of the official report of a National Research Council - National Academy of Sciences Committee, entitled "Possible Health Effects of Exposure to Residential Electric and Magnetic Fields" (released by NRC-NAS at 11:00 am EST this date).
Dr. Richard Luben, a Biomedical Sciences professor at the University of California, Riverside and president of the Bioelectromagnetics Society, along with two past presidents of the Society, Dr. Maria Stuchly of the University of Victoria (Canada), and Dr. Larry Anderson of the Pacific Northwest National Laboratory in Richland, Washington, all served on the NRC-NAS committee which compiled the report. They stated that "The most important aspect of this report is that it establishes that even under the strictest possible standards of proof, there is a reliable, though low, statistical association between power lines and at least one form of cancer. This fact in itself shows that we need to do more to find out why this relationship exists."
The NRC-NAS report concludes that although a statistical association can be shown between measurements of the current-carrying ability of power lines near residences and the relatively rare blood cancer, childhood leukemia, proof that this association is due to the electric or magnetic fields from the power lines is still lacking. Epidemiologic studies cited in the report show that households in the "high-wire-code" categories, which have higher-capacity wiring or are closer to power stations or high-energy transmission lines, show approximately a 1.5-fold increase in childhood leukemia over households with low capacity wiring or those farther away from power sources. In previous public statements, the Bioelectromagnetics Society has taken the position that more research is needed on the relationship between EMF exposure and cancer-like changes in cells, and on the possible mechanisms by which EMFs, perhaps in concert with other factors, may contribute to leukemia and other cancers in humans.
The report states on page 1 that "Based on a comprehensive evaluation of published studies relating to the effects of power-frequency electric and magnetic fields on cells, tissues, and organisms (including humans), the conclusion of the committee is that the current body of evidence does not show that exposure to these fields presents a human-health hazard." However, the report also concludes that "the energy policy act of 1992 is not anticipated to answer all the questions regarding the possible health effects..." and that "continued research is important..." It goes on to make several further points. To summarize some of these points, 1) a link appears to exist between distance to power lines and risk of at least childhood leukemia; 2) there are biological effects of magnetic fields down to at least 1 gauss [about twice the magnetic field of the Earth]; and 3) mammary [breast] tumor experiments need to be pursued. The concluding paragraph of the report indicates "continued research is important, however, because the possibility that some characteristic of the electric and magnetic field is biologically active at environmental strengths cannot be totally discounted. If ongoing or future research should uncover evidence of potential mechanisms that could lead to such a result, research should be continued to follow those leads and address that possibility."
Drs. Luben, Anderson and Stuchly agree with the report's key conclusions that the data are not convincing that there is a proven danger to the public from electromagnetic fields -- but also that EMF exposure does result in a number of biological effects. They caution against taking the attitude that a lack of confirmed proof at this point in the study of EMF effects means that the question can be ignored. They point out that even in the case of cigarette smoking, it took nearly 50 years after the demonstration of a statistical association with lung cancer for scientists to define a specific cellular mechanism by which compounds in smoke could definitely cause the cellular changes associated with lung cancer. They emphasize that, in the view of scientists, research is the only way to find the answers to unexplained observations such as the apparent link between EMF exposure and some forms of cancer.
"There are many factors contributing to all cancers," said Luben, "this report documents that EMF exposure produces a number of biological effects, both on cells in the laboratory and on animals, that could possibly play a role in cancer development." The report points out that none of these effects have been reliably demonstrated at the field strengths normally encountered as background levels in households, even those which may be at slightly higher risk for leukemia due to their "wire code" ratings. However, the three scientists emphasized that most of the studies published to date have been preliminary studies in which high "doses" of the suspected agent (EMF in these cases) are applied to demonstrate effects. More extensive studies are currently being funded by the National Institutes of Health, the Department of Energy, and companies in the energy and communications industries; results of these studies are scheduled to be evaluated and reported to Congress by NIEHS in 1998.
"In the final analysis," said Luben, "the approach taken by this Committee is the only way to answer the questions raised here or in any scientific disagreement. We looked at the available data with an objective, impartial attitude, asking what the data really showed and not what we wished it to show. We found a few answers, but there are still important questions that need to be addressed."
So what does everyone (anyone?) think about the NAS report?
The conclusions presented in a report are only as good as the data assessed and the assumptions made. Since the major assumption underlying the NAS/NRC report is not credible, the conclusions are not credible.
The NRC report concludes:
"No clear, convincing evidence exists to show...(EMFs) are a threat to human health...."
This conclusion is based on the assumption that emf biology has been allowed to proceed in its normal course to find such evidence, and such evidence has not appeared.
Since there is abundant documentation that emf biology has not been allowed to proceed in its normal course, the assumption underlying the conclusion is not credible and, thus, the conclusion is not credible.
The DOE sponsored NRC report is only the latest in the long string of reports intended to reassure the Public. But the Public sees the conflicts of interest; and they see that emf biology has not been allowed to proceed in its normal course. Thus, the NRC report will only generate more anger in the Public which will only generate more lawsuits; the Public's only recourse.
Its likely that only a few frequencies and modulations have health consequences; but an angry Public won't make such discriminations. Its already apparent that the Public is being pushed down the path that they were pushed down by the tobacco industry and before that by the asbestos industry.
As I wrote years ago, the funding entities don't seem to recognize that they are shooting themselves in the foot. They should read the book entitled "The March of Folly" by the historian Barbara Tuchman.
Allan H. Frey (email email@example.com)
11049 Seven Hill Lane (voice 301.299.5181)
Potomac, MD 20854, USA
EMF-BIO Usenet Newsgroup Archives
As pointed out in an opening talk at the San Antonio meeting by Richard Luben, president of the Bioelectromagnetics Society and an author of the report, the report and the NRC press release which accompanied it concluded that there is no "conclusive and consistent" evidence showing that exposures to residential electric and magnetic fields produces cancer, adverse neurobehavioral effects, or reproductive and developmental defects. Evidently few in the press realized the policy significance at the NRC of those two important words, "conclusive" and "consistent."
Like the more familiar phrase in law "beyond a reasonable doubt", "conclusive and consistent" implies a certain standard of evidence that warrants more serious action. Using that standard of evidence, the NRC Committee concluded that research results do not show that EMF exposure at a residential environmental level causes adverse health effects. The NRC report did not exclude the possibility of EMF health effects: neither did it rule out the possibility that new research results could provide conclusive and consistent evidence at some time in the future. In its systematic review of the literature, the NRC committee restricted themselves to considering only results published in peer-reviewed journals, so at the time the report was drafted - mid 1995 - no results from the US EMF RAPID program could be evaluated. The report itself is a careful analysis of most of the important studies, including one of the most complete considerations of the strengths and weaknesses of the EMF epidemiological studies published to date. It is well worth a careful reading for the detailed evaluation of the literature contained in the body of the report.
Far from calling for an end to EMF research, the report concludes with a chapter which makes specific research recommendations for studies needed to clarify unresolved issues. In particular, the report notes the evident validity of an association between indirect measures of power line exposure (based on wire code or historical line-load estimates) and childhood leukemia, and suggests that an effort should be made to determine what agent(s) may be responsible for this association. The press interpreted this as including only agents unrelated to magnetic field exposure such as traffic density, but the committee and the report itself considered other magnetic field metrics such as transients and ground currents as possible, perhaps even the most likely, agents.
Some of the more influential press reports greatly simplified the NRC report's conclusions by casting it as a simple pronouncement of no adverse EMF effects. Several EMF researchers at the San Antonio meeting speculated that characterizing the NRC report in this way was not just sloppy reporting but the result of a systematic effort on the part of those wishing to downplay concern about EMF. Those of us dealing with the public have noticed very little impact of the NRC report, but it is likely to have a greater impact in the House and Senate where budgets for US EMF research are decided. When those decisions are made, we can only hope that legislators can be given a better understanding of the words "conclusive and consistent" than the public has.
It is unfortunate the NAS-NRC committee set such a strict standard for evaluating the data: They looked for **CONCLUSIVE** evidence of a link to EMFs. When this requirement was not met, they were able to dismiss the EMF link to childhood cancer and tell the world that there was nothing to worry about.
This is a strange conclusion given that the panel said that the original association between childhood leukemia and wire codes, first reported by Dr. Nancy Wertheimer and Ed Leeper in 1979, was "statistically significant" and "robust in the sense that eliminating any single study from the group does not alter the conclusion that the association exists."
What the NAS-NRC committee was unwilling to conclude is that EMFs were responsible for the wire code link. What then are wire codes surrogates for? At this point, the committee threw up its hands and said they do not know.
According to the report:
"At present, confounding remains a possible explanation for the wire code and cancer association. However, past efforts to identify such confounders have failed and few strong candidates can be postulated at present." (p.153)
That is the committee has no idea what else --if not EMFs-- could be responsible.
Is it therefore fair for the committee to sound the all clear?
The committee also said the occupational EMF-cancer studies could be useful in explaining the EMF-wire code "paradox":
"The sources of bias are largely distinct for the studies of residential exposure and childhood cancer versus occupational exposure and adult cancer, so that if both research avenues have been misleading, they have been so in different ways. If occupational studies are pursued to clarify the issue and if they provide more conclusive evidence that magnetic fields can cause brain cancer and leukemia in adults, they will add more substantial indirect support to the proposition that magnetic fields can cause cancer in children." (p.161)
and, more specifically:
"Overall, the most recent studies have increased rather than diminished the likelihood of an association between occupational exposure to electric and magnetic fields and cancer, but they have failed to establish an association with a high degree of certainty." (p,169)
Here again the data cannot meet the strict burden of proof required by the NAS-NRC panel. But the occupational data, according the committee **DOES** support the childhood data.
I would agree with the NAS-NRC panel that there is no conclusive proof. But I would just as strongly disagree that we can tell families with small children that there is nothing to worry about as the academy did last Thursday and succeeded in putting this conclusion on the front pages of virtually every newspaper in America.
At the press conference, I asked Dr. Charles Stevens and Dr. David Savitz, the chair and the vice-chair of the committee, respectively, what probability (short of 100%) they would venture that a link between childhood leukemia and EMFs? Neither was willing to answer the question.
-------------------Louis Slesin, PhD -------------------
Ms. Christine A. Ervin
Assistant Secretary for Energy Efficiency
U.S. Department of Energy
1000 Independence Avenue, S.W.
Washington, D.C. 20585-0121
Dear Assistant Secretary Ervin:
The National Electric and Magnetic Fields Advisory Committee (NEMFAC), was established by Congress in the Energy Policy Act of 1992 to provide advice to the Secretary of Energy and to the Director of the National Institute of Environmental Health Sciences with respect to the Electric and Magnetic Fields Research and Public Information Dissemination Program (EMF RAPID), also established by that law. To that end, we are conveying to you our views on the recently released report, "Possible Health Effects of Exposure to Residential Electric and Magnetic Fields", from the National Academy of Sciences/National Research Council (NAS/NRC).
We take this action because, after perusal of the pre-publication NAS/NRC report released October 31, 1996, we conclude that neither the press release nor the Executive Summary of the report adequately reflects the conclusions to be found in the body of the report. Furthermore, the report's release received widespread national press coverage, much of which was misleading and could adversely impact funding decisions for the EMF RAPID Program as well as other EMF research programs. Continued research with adequate funding is essential to resolve the uncertainties about EMF health effects.
The NEMFAC wants to call to your attention the following important points:
* Contrary to reports in the popular press. the NAS/NRC report does not state that extremely low magnetic fields are safe. Rather, the report concludes that there is an unexplained, but statistically reliable and robust association between power transmission and distribution systems and childhood cancer and that continued research is necessary.
* The NAS/NRC report was commissioned before the results from the EMF RAPID program will be available. In addition, the report is limited to residential findings and reflects literature reviews only through 1994 plus 12 papers from 1995. It excluded the large body of work concerning occupational studies published throughout the same period.
* The Energy Policy Act of 1992 requires a final report to Congress from the EMF RAPID program on whether the research indicates a health hazard. Plans are now in development for proceeding with this mandatory assessment. We recommend that the EMF RAPID program's report to Congress include the following elements to improve upon the work done thus by the NAS/NRC or other reviewing bodies.
+ The results of childhood cancer epidemiology studies to be completed
in late 1997. These studies have quantitative evaluation of exposures and
better controls than previous studies.
+ The results of occupational epidemiology and exposure assessment studies.
+ Several animal studies currently in progress.
+ The results of cell studies that have been duplicated in multiple laboratories.
+ Findings from the EMF RAPID program expected in 1999. + The results of several major breast cancer studies expected in 1998.
* The U.S. Congress, the U.S. utility industry, and many foreign governments have, over the last few years, invested funds in research of health effects of extremely low frequency EMFs. Those steps have been taken in response to public concern as well as to the provocative results of early EMF research. Although this research is focused and well coordinated, the issues are complex and numerous questions have not yet been answered.
* While the EMF RAPID program is entering its 5th year since enactment of the Energy Policy Act, research was not funded until late 1994. Because of this delay, the Program is just now reaching the full potential envisioned by Congress. The Department of Energy (DOE) and the National Institute of Environmental Health Sciences (NIEHS) have worked cooperatively to foster research programs which encompass basic biological research into possible mechanisms for cell effects, cancer development (including breast cancer), and the role of melatonin as affected by EMFs.
* In summary, it will be a violation of public trust and a waste of scientific effort and money (federal and private) if the EMF RAPID program is not finished. We strongly urge that level federal funding continue until the Program is finished, the data analyzed, and the report to Congress completed. At that point, decisions about the future of federal EMF research could logically proceed.
Lastly, I wish to bring to your attention an evaluation by the Harvard Center for Risk Analysis which stated in its March 1996 issue of Risk in Perspective: "Few of the elevated risks seen in those studies (childhood leukemia and EMF) are above 3 and many lie in the 1.5-2 range. Relative risks in this range are considerably lower than those seen in studies of known human carcinogens such as cigarettes. It should be noted, however, that there are other well accepted associations, such as the association between smoking and heart disease, that fall in this range, Furthermore, a relative risk of 2 (a doubling of the risk of childhood cancer) coupled with the widespread exposure to EMFs, could have a potentially significant impact on the population."
I share this view that any potential EMF health risks could have significant public health implications. Therefore, EMF research is an important public policy concern, and I will be happy to address any questions that you may have about this matter or discuss the EMF RAPID program with you.
Shirley D. Linde Chairperson, NEMFAC