To: EQB Members
Technical Representatives
From: John P. Hynes, Staff
296-2871
Subject: Electric and Magnetic Fields of Power Frequency Transmission Lines
ISSUE
The Minnesota Environmental Quality Board has had the responsibility to route high voltage transmission lines (lines over 200 kilovolts) since 1973. Public concern over the effects of the electric and magnetic fields emanating from transmission lines has been expressed in each routing process. The Board has a responsibility to respond to these concerns and has responded through specific field research, expert consultation, and periodic updates of current research by staff.
There are no Minnesota regulations pertaining to magnetic field exposure from powerlines The Board has imposed, on a case by case basis, a maximum electric field limit of 8 kV per meter measured one meter above the ground and 5 milliampere maximum steady state short circuit to ground. These are imposed to limit the maximum electric shock a person could receive from a large insulated metallic object under a powerline.
The last full review of the research on this issue for the Board was in 1993. The Board contracted with Asher Sheppard. Ph.D., a consultant in environmental science. Dr. Sheppard indicated that health effects had not been conclusively demonstrated by any one study on human beings or animals, nor by the body of evidence from epidemiology and laboratory studies of animals, tissues, and cells. He concluded that the outlook was for continuing controversy until possibly 1998. At that time the results of several major research projects in epidemiology of childhood leukemia and several studies of cancer in animals that were begun in the 1991-1992 period should be available along with the results of the work authorized by Congress in the Energy Policy Act of 1992.
The US Department of Energy and the National Institute of Environmental Health Sciences coordinated the work under the Energy Policy Act (EMP RAPID Program) and two of the three major reviews of all the research completed through the middle of 1998 have been released. The National Research Council was asked to review the EMF RAPID program implemented by DOE and the NIEHS. The NRC report was released in 1999 prior to the NIEHS final report. It concluded that the current body of evidence does not show that exposure to these [electric and magnetic] fields presents a human health hazard. It also recommended “that no further special research program focused on possible health effects of power-frequency magnetic fields he funded.”
The NIEHS report was released in June 1999. The conclusions are in the Background section of this memorandum. In the cover letter to the report (Attachment B) the Director of NIBHS emphasized that the conclusion in the report, that ELF-EMF exposure cannot be recognized as entirely safe because of weak scientific evidence that exposure may pose a leukemia hazard, is insufficient to warrant aggressive regulatory concern, He went on to say that “because virtually everyone in the United States uses electricity and therefore is routinely exposed to ELF-EMF, passive regulatory action is warranted such as a continued emphasis on educating both the public and the regulated community on means aimed at reducing exposures”. (Emphasis added.)
It is the staff’s opinion that electric and magnetic fields emanating from transmission lines do not constitute a potential for significant environmental effect. The staff agrees with the position of the NTEHS that there is insufficient evidence to warrant aggressive regulatory concern. However, the Board should continue to monitor the research being carried out and to continue to inform the public.
ACTION
For your information.
BACKGROUND
The issue of public health and safety effects of high-voltage overhead transmission lines has been before the Minnesota Environmental Quality Board since the passage of the Power Plant Siting Act in 1973 gave the Board the responsibility of routing all electric transmission lines over 200 kilovolts (1W). In the decades prior to the late 1970’s, the use of electricity was increasing at a rate of 7% per year. This means that the capacity to generate and transmit electric energy had to be doubled every ten years. Larger and larger power plants and miles and miles of transmission and distribution lines were being constructed. The voltages of the transmission lines were also being increased to reduce the number of miles of right-of way needed and to reduce electrical losses.
In the middle 1970’s, the Board designated routes and issued construction
permits for a number of high voltage transmission line including more than 170
miles of ± 400 kV Direct Current (DC), and 350 miles of 500 kV Alternating
Current (AC) transmission lines. These were and still are the highest voltage
lines constructed in
People’s reactions to these projects ranged from anger that they could be
forced to give up a right-of-way through the utility’s right of eminent domain
(even though they would receive compensation), to concern that nearby property
values would decline with or without compensation. to fear of the health
effects from fields emanating from the operation of the powerlines. The
procedures of eminent domain were established by the Legislature long ago and
have been implemented for many years through the Courts. The Board does not
have any responsibility for eminent domain process or its outcomes.
However, the Board does have a responsibility to protect the environment and the public health and safety with regard the high voltage transmission lines that are routed by the Board. The Board has done this in a number of ways. For example, with the ±4001W DC transmission line the health concerns focused on the effect on people and livestock of air ions generated by the line. The Board carried out unique and original field research to measure the electrical environment down wind of the operating line. It discovered that the environment down wind of the line was changed beyond a mile. (Attachment A #5) However the review of the literature by the Board’s seven Science Advisors in 1981 did not show anything that might be harmful to humans or the environment. (Attachment A #3) And in 1982, a statistical analysis of Dairy Herd Improvement Association records could not find any difference between dairy herds near the line and herds away from the line. (Attachment A #4)
In the late 1960’s and early 1970’s the possibility of adverse health
effects resulting from exposures to AC electric fields received the primary attention.
Magnetic fields were not considered strong enough to have an adverse affect.
(The voltage on the tine produces electric fields and the current on the line
produces magnetic fields.) After considerable electric field research failed to
confirm the original reports from the
In order to analyze the possibility that any exposure, such as that to 60-Hz magnetic fields, could present a health risk to humans, one must consider the results from three complementary areas: epidemiology, laboratory research, and exposure assessments. Epidemiological studies have examined possible associations between electric and/or magnetic fields from power lines and human health risk. Laboratory studies have examined biological responses, both in humans, whole animals and in isolated cells and tissues, to electric and/or magnetic fields. Exposure assessment studies have attempted to quantify the exposure that individuals may receive in the course of their normal life at home, in schools, at work, etc. It is generally agreed that the use of epidemiological, laboratory, and exposure assessment data provides important complementary information needed for any balanced evaluation of potential risk. Over twenty independent scientific groups in the past 20 years have evaluated the evidence from human, animal and exposure assessment research on the potential health effects associated with exposure to electric and magnetic fields.
Research Funding and Review.
Research in the
Pre-1992 Expert Panel Reviews of the EMF Health Issue.
Many different groups of expert scientists have reviewed the data relevant to the question of whether exposure to power frequency electric and magnetic fields is associated with adverse health effects. All of these groups have concluded that the body of data, as large as it is, does not support the conclusion that exposure to power-frequency electric or magnetic fields (at intensities that span the lowest recorded environmental levels to those ~v that far exceed environmental and usual occupational exposures) causes cancer or otherwise constitutes a health hazard. Although some epidemiological studies using surrogate measures have reported associations, other studies have not. However, because of the few residential studies that have pointed to possible positive associations between exposure and development of cancer, particularly childhood cancer, many of the expert panels have acknowledged the need for further research and monitoring of the issue.
EMF-RAPID.
In 1992 Congress established a five year federally coordinated effort to evaluate developing technologies and to carry out research on the effects on biological systems of exposure to 60 Hz electric and magnetic fields and to communicate these results to ~, the public sector. The National Institute of Environmental Health Sciences (NIEHS) and the Department of Energy (DOE) coordinated the implementation of the Electric and Magnetic Fields (EMF) Research and Public Information Dissemination (RAPID) Program.
The Department of Energy was responsible for the administration of funding and for developing technologies to characterize and mitigate these fields. NJEHS was responsible for the coordination and conduct of studies to evaluate the possible adverse health effects related to exposures to these fields. DOE and NIH-IS shared the responsibility for communication of research findings and scientific knowledge to policy makers and the public. NIEHS received $30 million from the RAPID program and contributed another $14.5 million from its own programs. This program officially concluded at the end of 1998
NIEHS. The NIEHS was charged by Congress to prepare and submit an evaluation of the potential human health effects from exposure to extremely low frequency (ELF) (50-60 Hz) electric and magnetic fields (EMF). To evaluate the quality of the science and the strength of the evidence for the potential human health effects, the NIEHS organized a comprehensive review of the data that included:
1) Three scientific symposia to discuss and evaluate the quality of the research findings in these study areas: a) theoretical and in vitro research findings; b) epidemiological results: and c) in vivo experimental and clinical laboratory findings. Symposia participants reviewed the quality and reproducibility of the studies and discussed the degree to which the scientific evidence can support a causal linkage between EMFs and biological and/or health effects in each of the study areas.
2) A working group of scientists both within and outside the field of EMF research to ensure cross-disciplinary discussion of experimental findings, broad scientific perspective, and critical review and evaluation of the research data. Several different sources of information were reviewed by the working group including discussion reports from the three symposia; a comprehensive, critical review of the scientific literature; and other pertinent information and experimental data. The working group report draws conclusions on the strength and robustness of the experimental data related to extremely low frequency EMF exposure and its implication for human health and disease etiology.
NIEHS Working Group Report. In August 1998, the working group released their report. In brief, a majority (19 of 28) of the panel of experts concluded that electric and magnetic fields like those surrounding electric power lines should be regarded as a ‘possible human carcinogen.’ The ranking system used by the working group was developed by the International Agency for Cancer Research and has four categories by which it characterizes the evidence for carcinogenicity.
1. Sufficient evidence — the agent is a known human carcinogen
2. Limited evidence — the agent is a probable (2A) or possible (2B) human carcinogen
3. Inadequate evidence — there is insufficient evidence upon which to base a decision
4. There is consistent evidence that the agent is not a human carcinogen
No members of the panel concluded that electric and magnetic fields are known (I) to he carcinogenic to humans nor did any member conclude that EMFs were probably (2A) carcinogenic to humans. The conclusion, that it was a possible (2B) human carcinogen, was based largely on epidemiological evidence in the face of animal and other laboratory studies that the panel agreed did not support or refute the population studies. Eight of the members of the panel found that EMF is not classifiable as to carcinogenicity, while one member said EMF probably is not carcinogenic to humans.
Comments on the working group report were received by the NEIHS through
“The scientific evidence suggesting that ELF-EMF exposures pose any health risk is weak. The strongest evidence for health effects comes from associations observed in human populations with two forms of cancer: childhood leukemia and chronic lymphocytic leukemia in occupationally exposed adults. While the support from individual studies is weak, the epidemiological studies demonstrate, for some methods of measuring exposure, a fairly consistent pattern of a small, increased risk with increasing exposure that is somewhat weaker for chronic lymphocytic leukemia than for childhood leukemia. In contrast, the mechanistic studies and the animal toxicology literature fail to demonstrate any consistent pattern across studies although sporadic findings of biological effects (including increased cancers in animals) have been reported. No indication of increased leukemia in experimental animals has been observed.
‘The lack of connection between the human data and the experimental data (animal and mechanistic) severely complicates the interpretation of these results. The human data are in the ‘right species, are tied to ‘real-life’ exposures and show some consistency that is difficult to ignore. This assessment is tempered by the observation that given the weak magnitude of these increased risks, some other factor or common source of error could explain these findings. However, no consistent explanation other than exposure to ELF-EMF has been identified.
“The ultimate goal of any risk assessment is to estimate the probability of disease in an exposed population. In general, this involves the combination of three basic pieces of information the probability that the agent causes the disease, the response as a function of exposure given that the exposure does cause disease and the distribution of exposures in the population being studied. The NIEHS believes that the probability that ELF-EMF exposure is truly a health hazard is currently small. The weak epidemiological associations and lack of any laboratory support for these associations provide only marginal, scientific support that exposure to this agent is causing any degree of harm.
“Epidemiological studies have serious limitations in their ability to demonstrate a cause and effect relationship whereas laboratory studies, by design, can clearly show that cause and effect are possible. Virtually all of the laboratory evidence in animals and humans and most of the mechanistic work done in cells fail to support a casual relationship between exposure to ELF-EMF at environmental levels and changes in biological function or disease status. The lack of consistent, positive findings in animal or mechanistic studies weakens the belief that this association is actually due to ELF-EMF, but it cannot completely discount the epidemiological findings.
“The NIEHS concludes that ELF-EMF exposure cannot be
recognized as entirely safe because of weak scientific evidence that exposure
may pose a leukemia hazard. In our opinion, this finding is insufficient to
warrant aggressive regulatory concern. However, because virtually everyone in
the
‘The interaction of humans with ELF-EMF is complicated and will undoubtedly continue to be an area of public concern. The EMF-RAPID Program successfully contributed to the scientific knowledge on ELF-EMF through its support of high quality, hypothesis-based research. While some questions were answered, others remain, Building upon the knowledge base developed under the EMF-RAPID Program, meritorious research on ELF-EMF through carefully designed, hypothesis-driven studies should continue for areas, neurodegenerative diseases and cardiac diseases associated with heart rate variability, have identified some interesting and novel findings for which further study is ongoing.”
In the cover letter to the report (Attachment B) the Director of NIEHS emphasized that the conclusion in the report, that ELF-EMF exposure cannot be recognized as entirely safe because of weak scientific evidence that exposure may pose a leukemia hazard, is insufficient to warrant aggressive regulatory concern. He went on to say that “because virtually everyone in the United States uses electricity and therefore is routinely exposed to ELF-EMF, passive regulatory action is warranted such as a continued emphasis on educating both the public and the regulated community on means aimed at reducing exposures”. (Emphasis added.)
Two other reports regarding the EMF-RAPID program warrant mentioning; the National Academy of Sciences and the Inter-Agency Committee reports.
U. S. National Academy of Sciences. The NAS through its National Research Council was asked to review the RAPID program implemented by DOE and the NWHS. Its final report was released in 1999 prior to the NTEHS report and it concludes the following:
“An earlier Research Council assessment of the available body of information on biologic effects of power-frequency magnetic fields (NRC 1997) led to the conclusion “that the current body of evidence does not show that exposure to these fields presents a human health hazard. Specifically, no conclusive and consistent evidence shows that exposures to residential electric and magnetic fields produces cancer, adverse neurobehavioral effects, or reproductive and developmental effects”. The new, largely unpublished contributions of the EMF-RAPID program are consistent with that conclusion. We conclude that no finding from the EMFRAPID program alters the conclusions of the previous NRC review on the Possible Effects of Electromagnetic Fields on Biologic Systems (NRC 1997). In view of the negative outcomes of EMF-RA.PID replication studies, it now appears even less likely that MFs [magnetic fields] in the normal domestic or occupational environment produce important health effects, including cancer.”
It also recommended “that no further special research program focused on possible health effects of power-frequency magnetic fields he funded.”
Inter-Agency Committee. The final report charged in the Energy Policy Act of 1992 is the report of the Inter-Agency Committee. The Inter-Agency Committee, representing nine federal agencies, will make its own report to Congress. The nine agencies are the Department of Defense, the Department of Energy, NIEHS, the Environmental Protection Agency, the Department of Transportation, the Occupational Safety and Health Administration, the Rural Utility Services, the Federal Energy Regulatory Commission, and the National Institute of Standards and Technology. This report has not been completed but is expected this fall.
Other Recent Reviews, Publications, Ongoing
Programs, and News Items.
World Health Organization. WHO has an International EMF Project on ELF and static EMF research and human health co-sponsored by the International Commission on Non-Ionizing Radiation. The scientific working groups convened in 1997 by WOE have published consensus conclusions in April 1999. Examples are as follows. Additional work is being carried out.
‘Taken together, the findings of all published studies are suggestive of an association between childhood leukemia and estimates of ELF magnetic fields. Epidemiologic studies examining health outcomes other than cancer “do not provide sufficient evidence to support an association between ELF magnetic field exposure and adult cancers, pregnancy outcome, or neurobehavioral disorders.
“Although health hazards exist from exposure to ELF fields at high field strengths, the literature does not establish that health hazards are associated with exposure to low-level fields, including environmental levels.”
“The results show little indication of an increased risk of childhood leukemia either from magnetic or electric fields or from residential power line configurations.”
A second Canadian epidemiological study published in June did not find an association between leukemia and proximity to high current configuration power lines, However they indicated that personal dosimetry might be better to measure exposure than the size of the conductor.
There is a large epidemiologic study of childhood leukemia being
conducted in the San Francisco Bay Area and the
News Item. There has been recent news in the media that one of the most visible figures of EMF research, Dr. Robert P. Liburdy, formerly a staff biochemist at Lawrence Berkeley National Laboratory, CA, had engaged in “scientific misconduct.” The laboratory work in question was published in 1992 and was potentially very important because it appeared to link EMF and calcium signaling, a fundamental cell process governing many important cellular functions.
Liburdy denies that he had falsified data, acknowledging only that the “graphing techniques” he used to visually portray experimental data may have given a wrong impression of the results. He has left the Laboratory and has agreed to retract three figures in his papers.
There are currently no
Recent MEQB Decisions.
The Board has taken action on several projects since 1993 that included the consideration of electric and magnetic fields. (See Attachment C.) They have been aided by a 1993 report entitled ‘Epidemiologic and Laboratory Research on the Potential Human Health Effects from Exposure to Power Frequency Electric and Magnetic Fields” which was prepared by Dr. Asher Sheppard for the Board. The report was used to assist the Board in regulatory decisions for new electric energy facilities; and, is a summary of EMF background and scientific data in 1993 addressing concerns regarding EMF exposure and human health. Dr. Sheppard reported that:
Laboratory research shows that electric and magnetic fields are biologically active under specific conditions.
Health effects have not been conclusively demonstrated by any one study on human beings or animals, nor by the body of evidence from epidemiology and laboratory studies of animals, tissues, and cells. There are also many negative results in all areas of study.
Dr. Sheppard concluded that:
Over the next three years, [through 1996] the outlook is for continuing controversy with little chance of a scientific resolution.
By mid-1996, a number of new reports in all areas of study will have appeared, but it is unlikely that the forthcoming data will have an impact so overwhelming as to bring about a new consensus of opinion.
However, by 1998, the results of several major research projects in epidimiology of childhood leukemia and several studies of cancer in animals that were begun in the 1991-1992 period should be available….Together, the new information available by the middle or latter part of 1998 is likely to have a major impact.
Recent RAW Petition. In 1996
the Board denied a petition for an EAW to determine any adverse health effects
for the City of
Staff Observations and Recommendations.
Dr. Sheppard was correct that in 1996 there was not a new consensus of opinion and in 1998 the results of many new major studies were available. The new information however has not completely cleared up the issue. There is still weak epidemiological evidence that exposure may pose a leukemia hazard to humans. Epidemiological studies have serious limitations in their ability to demonstrate a cause and effect relationship. Laboratory evidence in animals and humans and mechanistic work done in cells fail to support a causal relationship between EMF and changes in biological function or disease status. It is clear that the NEIS does not believe that other cancers or non-cancer health outcomes provide sufficient evidence of a risk to warrant concern.
The EMF-RAPID program was well planned and implemented under open scrutiny. The NIEHS report is the state of the knowledge of all the research published through the middle of 1998. Additional studies have been published since 1998 or are still being carried out. The studies published this year have not established any causal link between EMF and adverse health effects.
The staff agrees with the position of the NIEHS that the probability that ELF-EMF exposure is truly a health hazard is currently small and that there is insufficient evidence to warrant aggressive regulatory concern. However, the Board should continue to monitor the research being carried out and to continue to inform the public. It is the staffs opinion that electric and magnetic fields emanating from transmission lines do not constitute a potential for significant environmental effects.