Historical introduction to EMF health effects

Stephan P. Albert Bren Madigan Army Medical Center

Tacoma, WA

he ancient Greeks knew that amber T could attract particles such as chaff and feathers. William Gilbert, physician to Queen Elizabeth I of England, appears to have been the first to systematically study this effect in the late sixteenth century. Gilbert found that a number of substances had attractive abilities, which he believed arose from a subtle effluvium that was released after rubbing and which pushed away the air. Air flowing back to the surface, Gilbert thought, brought with it light particles such as chaff. This theory was discredited by later experiments that showed that charged objects retained their attraction in the absence of air.

The first electrical machine was invented in the mid-17th century by Otto von Guericke. It consisted of a cast sphere of sulphur that could be rubbed while being rotated on an iron rod. Later investigators replaced the sulfur with a glass rod or hollow sphere of glass and (still later) added natural rubber to “rub” the sphere, a metal pipe to “draw off’ the electricity, and mechanisms to turn the sphere. In 1745, the Leyden jar was invented, which stored electricity and enabled scientists to study the effects of stronger electricity.

As electrical technology developed, it engendered the interests of physicians and scientists in electrical phenomena and their biological effects. Experimenting on himself and volunteers, Gottlieb Krueger found that the pulse-rate increased during electrification, motivating him to re- comend it as a form of treatment for ail- ments he believe arose from impaired blood circulation. Jean Jallabert treated a craftsman whose arm had become para- lyzed by stimulating it regularly with electricity, restoring movement ot the arm after several months of treatment. By the late eighteenth century, electricity was regularly used for the treatment of paraly- sis arising from accidents, rheumatism, and tetanus.

In the early eighteenth century, dis- sected frogs were regularly used to show the effects of “static electricity” (as we would call it today). It was while investigating these effects that a physician, Luigi Galvani, made the monumental discovery

of his time: that two dissimilar metals brought into contact with a frog muscle could cause the muscle to contract. This discovery would eventually lead to the concept of electrical current.

Galvani believed that two dissimilar metals, when brought into contact with the frog muscle, somehow disturbed its electrical equilibrium, giving rise to a previously unknown form of electricity. Allessandro Volta, a physicist, initially accepted Galvani’s theory of “animal electricity.” However, subsequent experiments led him to question Galvani’s theory on the origin of animal electricity. Through his development of the first bat- tery, the electric pile, Volta was able to show that this new form of electricity could be generated independently of animals and that it was a property of metals [2]. This electricity was named “Galvanic current” in honor of its initial discoverer.

The nineteenth century saw rapid developments in electrotechnology, and also in medical uses of electricity and magnet- ism. In 1842, Guillaume Benjamin Duchenne undertook experiments in elec- trotherapy, and reported that galvanic stimulation of muscles was an excellent tool in the differential diagnosis of paraly- sis. Work by Du Bois-Reymond, Herman von Helmholtz, and other physiologists in the mid-19th century on nerve polariza- t ion, threshold stimulation, electro- tetanus, and the speed of transmission of nerve impulses lay the basis for the modern science of electrophysiology [ 11.

Through the nineteenth century, attention began to shift from the applications of static electricity in medicine and phsy- iology to those of galvanic current. Just two years after Volta published his papers on the electric pile in 1810, physicians were already using galvanic current to stimulate the union of bone fractures [6]. By the mid-l850s, surgeons were regularly using galvanic current to heat various instruments, principally to effect cautery [I]. Further investigations into therapeutic applications of electricity were motivated

24 IEEE ENGINEERING IN MEDICINE AND BIOLOGY 0739-51 75 /96 /$5 .0001996 July/August 1996

by the theoretical developments in elec- tromagnetics of Faraday, AmperC, Gauss, Maxwell, and others, and by the development of sources of alternating current. Prominent among these investigators were Jacques Arsene d’Arsonva1 and Nik- ola Tesla.

D’ Arsonval studied the physiological effects of alternating currents, of time- varying electric and magnetic fields, and, eventually, of high-frequency fields, including effects such as muscle stimulation, pulse changes, perspiration, and nervous stimulation and their variation with frequency of the applied stimulus. d’Arsonva1 also examined the effects of induced currents via capacitive or induc- tive coupling, or “autoconduction” as it was called. Tesla investigated physiological effects of alternating current and time- varying fields. He reported that (quite strong) electric fields in the short wave range could kill isolated tuberculosis ba- cilli, a discovery that was heralded by newspapers as new cure for tuberculosis.

In 1899, the heating effects of time- varying fields and high-frequency currents on biological materials were recognized, and theorized by physiologists as arising from simple resistive losses. Karl Franz Nagelschmidt began investigating these heating effects in the early 1900s. He introduced the term “diathermy” and developed the theory that the heating arose from molecular oscillation induced by high-frequency currents [ 1,4].

Antonin Gosset is credited with being the first to explore the bioeffects of rddiof- requency fields when, in 1924, he and his coworkers used shortwaves to destroy tu- mors on a plant, with no damage to the plant itself. Subsequently, in 1926, Joseph Williams Schereschewsky began to inves- tigate such effects on animals [ I ] . Scher- eschewsky reported that he could kill flies with his shortwave equipment. Newspa- pers promptly announced that he had discovered a new death ray.

Through the 1930s and 1940s, dielec- tric studies on tissues and other materials were undertaken in the shortwave range. Many investigators during this period tried to elucidate the mechanism of action of shortwave radiation on tissues. Were the effects due primarily to resistive heating, or did athermal effects exist as well? Was it simple bulk heating or selective heating to specific sites of microscopic dimensions? Previously, d’ Arsonval had demonstrated that high-frequency fields in the long-wave region were beneficial

for the treatment of certain forms of rheumatism, arthritis, and gout. Shortwaves appeared to be even more effective. Some believed that this was due to the greater “penetrating ability” of shortwaves. Oth- ers thought that the heating of tissues was frequency-dependent, and that one had merely to “tune in” to the right frequency to heat a particular tissue [lo]. Clearly, there were many unanswered questions regarding the mode of interaction of nonionizing radiation with tissues.

Early experiments seemed to indicate that radiofrequency energy at 2450 MHz was absorbed by water nearly 7000 times more strongly than at the commonly used shortwave diathermy frequency of 21 MHz. As a result, the Federal Communi- cations Commission (FCC) in 1946 assigned the frequency 2450 MHz for use by physical medicine, based upon its as- sumed therapeutic value [4]. Unfortu- nately, these early studies did not account for such factors as geometry of the body and the limited depth of penetration of such energy into tissue, which may be more important factors than bulk absorption coefficients alone. This decision by the FCC led to the present use of 2450 MHz by most modern microwave diathermy equipment, home microwave ovens, and industrial food processing units

The 1930s and 1940s were also a period in which initial attempts were made to define an acceptable exposure metric. For example, in 1941, a team of physicians and engineers measured the energy absorbed in a patient during shortwave diathermy to within 5 percent. Results of the study were expressed in terms of energy absorbed per volume of tissue (W/li- ter), which is similar to the current exposure metric, the specific absorption ratio, measured in W/kg [4].

Through the first half of the twentieth century, RF energy found growing appli- cation in industry, science, medicine, communication, transportation, and national defense. The heating effects of RF energy were employed successfully in the treatment of cancer, physical therapy, food processing, and in industrial heating applications such as in the fabrication of plywood [12]. Yet, as ever more powerful sources of RF radiation were developed, the potential hazards associated with exposure to them became increasingly evi- dent, as well as the corresponding need to develop appropriate RF safety standards.

[4, 121.

Development of RF Radiation Exposure Standards

Since the earliest investigations into biological effects of electricity, time- varying fields, and RF radiation, scientists and physicians have worried about their potential health hazards. The electric shocks that one could receive from a Ley- den jar made early investigators appreci- ate the power of electricity; as did burns from early therapeutic applications of RF energy.

The beginning of the twentieth century marked a period of intense interest of physiologists into the modes of interaction of RF energy with biological systems. Scientists speculated about thermal and athermal effects. One athermal effect-the ability of strong RF fields to cause cells to line up into “pearl chains”- was shown in 1927 [ l l ] . However, the most obvious effects in humans from exposure to RF energy of therapeutic inten- sity were thermal, and these effects began to draw attention in the 1920s.

Work on fever therapy had shown that elevated temperatures had beneficial effects, but also potential adverse effects such as increased blood pressure, dizziness, physical weakness, disorientation, and nausea. In 1930, employees at a Gen- eral Electric plant in Schenectady, New York that made high-power shortwave tubes reported such symptoms associated with exposure to RF radiation [13]. Also in 1930, the U.S. Navy Bureau of Medi- cine and Surgery began to examine such effects after Navy personnel complained of fever-related symptoms such as nausea and dizziness.

In the 1930 Navy study, laboratory animals were subjected to a range of high- frequency current to induce elevated body temperatures. Subsequently, human volunteers were exposed to RF radiation under closely controlled conditions. The Navy study found that all symptoms induced in the human volunteers by exposure to shortwave radiation were similar to those of fever. All volunteers recovered from the exposures, with no sign of per- manent damage or athermal effects. Ex- posed laboratory animals lived to produce normal offspring 1141. Later studies also produced similar findings. The military investigators recommended that high- power RF equipment should be used with caution and that unnecessary exposure should be avoided. The Navy did not develop exposure standards at that time, however.

July/August 1996 IEEE ENGINEERING IN MEDICINE AND BIOLOGY 25

In 1948, researchers at the both the Mayo Clinic and the University of Iowa reported that cataracts could be induced in laboratory animals by RF exposure. The University of Iowa group also found tes- ticular degeneration in some laboratory animals Cl.51; other researchers reported similar findings [4]. A few years later, a physician at the Hughes Aircraft plant in Culver City, CA, reported cases of inter- nal bleeding among radar equipment workers. This report aroused considerable concern within the U.S. Department of Defense (DOD).

Increasing Cold-war tensions with the Soviet Union motivated the development of early-warning radar networks, which raised the issue of possible danger to personnel and civilians from exposure to the RF energy from their transmitters. In 1953, the U S . Navy and Air Force held a series of meetings to assess the problem and how it should be addressed [4,15].

Two findings emerged from these planning sessions. One was that exposure to RF radiation could be dangerous and even fatal, and that some determination of what constitutes a safe level of exposure was needed. The second finding was that few experienced investigators and laboratories were capable of performing the nec- essary research, which indicated the need for an aggressive research program.

In 1954, the DOD initiated a $13 million program to support research in the bioeffects of RF radiation, entitled the Tri-Service Program. Initially, laboratories were established at the Air Research and Development Command in Cam- bridge, MA, the Naval Medical Research Institute in Bethesda, MD, and the School of Aviation Medicine at Randolph Field, TX, to study bioeffects using a wide range of exposure conditions. The DOD also sponsored research at university and government laboratories across the United States. The research was intended to determine the threshold for injury from acute exposure to RF energy.

The results of these studies were pre- sented at a series of symposia held from 1957 through 1960. Most studies reported that the bioeffects of RF energy were thermal in origin, either through localized or general hyperthermia [4]. Exposures above 100 mW/cm2 consistently produced adverse effects, while those below 10 mW/cm2 elicited few consistent effects.

Based on engineering and biophysical calculations, Herman Schwan at the Uni-

versity of Pennsylvania suggested, in 1953, that 10 mW/cm2 would be a safe exposure limit. By this time, after nearly two decades of radar operation, no obvious health problems had emerged among personnel. This combination of experimental (animal) research, calculations, and absence of apparent injuries, led Schwan and others to recommend an exposure level of 10 mW/cm2. The Tri-Serv- ice program ended, and further efforts to develop exposure standards were carried out under auspices of the American Stand- ards Association (later renamed the American National Standards Institute).

To assist with standards development, in 1960, the Institute of Electrical and Electronics Engineers (IEEE) and theU.S. Navy sponsored the Radiation Standards Project. Committee C95 developed draft standards and submitted them for ap- proval to the American Standards Asso- ciation. The first ANSI standard, issued in 1966 (ANSI C95.1-1966), incorporated the 10 mW/cm2 limit. This standard was backed by theoretical and experimental investigations. As usual with ANSI standards, this standard was subject to review every five years.

However, research being conducted in the Soviet Union and Eastern Block Coun- tries at the time suggested the need for even lower safety limits. For example, Soviet investigators reported effects on the human central nervous system at exposure levels below 10 mW/cm2. Conse- quently, in 1958, Soviet researchers recommended a safe exposure limit of 10 p,W/cm2 for RF radiation, three orders of magnitude below the ANSI Standard. Western researchers criticized this Soviet research on both philosophical and meth- odological grounds, such as lack of ade- quate reporting on methodology and data, limited statistical analysis, inadequate controls, and subjective interpretation of the data. On the other hand, in 1961, So- viet researchers were the first to demon- strate the strong dependence of absorbed RF energy on the geometry and orienta- tion of the exposed object [4]. This lower Soviet standard has been an enduring source of controversy, and was a subject of discussion in the U.S. Congress when the first legislation to address potential hazards of RF energy was developed.

Other RF exposure standards were developed in the West as well. The National Council on Radiation Protection and Measurements (NCRP), an independent organization chartered by the Congress,

issued a report in 1981 on physical pa- rameters and mechanisms of interaction of RF radiation with matter [42]. Later, in 1986, the NCRP issued a two-tiered exposure standard that separated occupational from nonoccupational exposures [43]. This standard had a five-fold difference in exposure limits for occupational and nonoccupational exposure, which corre- sponds roughly to the ratio of a 40 hr work week to a 168 hour calendar week [43].

RF radiation exposure standards have also been developed by the American Conference of Governmental and Indus- trial Hygienists and by foreign organizations such as the National Radiological Protection Board (NRPB) of Great Britain [44]. Additionally, the International Non- Ionizing Radiation Committee (INIRC) of the International Radiation Protection As- sociation (IRPA), in conjunction with the World Health Organization (WHO), rec- ommends guidelines on exposure limits, drafts safe practice codes, and works with other international bodies to promote safety and standardization in the non-ionizing field [45].

A major public issue arose with the discovery in 1966 that some General Elec- tric television sets emitted X-radiation. By August of 1967, the Congress had held formal hearings, and nine separate bills had been introduced to address radiation safety. Although the problems posed with GE’s television sets did not entail RF radiation, the government inquiry quickly expanded to that part of the spectrum as well. A government survey revealed that many microwave ovens leaked microwave radiation exceeding the 10 rnW/cm2 limit.

Numerous researchers testified during the 1960s at congressional hearings held on these issues. Eventually, the Congress imposed restrictions on the manufacture and sale of radiation emitting products. The Radiation Control for Health and Safety Act of 1968 (Public Law 90-602) required the Secretary of Health, Educa- tion, and Welfare (now Health and Human Services) to develop and administer performance standards for electronic products, conduct efforts to minimize human exposure to RF radiation, and evaluate the effectiveness of these efforts [16]. In- itially, these tasks were assigned to the Bureau of Radiological Health (BRH).

The BRH began two efforts to address microwave oven safety. First, it formed

26 IEEE ENGINEERING IN MEDICINE AND BIOLOGY July/August 1996

the Technical Electronics Products Radia- tion Safety Committee (TEPRSC) to review BRH standards development. Second, the BRH sponsored a conference at the University of Virginia in September of 1969 to assess the current scientific knowledge on RF bioeffects and recommend an appropriate course of action. Mi- crowave oven manufacturers were represented by the Association of Home Appliance Manufacturers (AHAM), which held discussions with the BRH and TEPRS C .

The conference assessed the state of the knowledge at the time. The Tri-Serv- ice program had generated much knowledge about RF bioeffects, but many of its studies were qualitative and lacked ade- quate dosimetry. For example, many researchers had simply placed animals in front of an antenna and monitored physiological endpoints, without measuring the energy absorbed by the animals. No exposure metric existed that could be corre- lated with observed effects.

During the next two years, the BRH, TEPRSC, and AHAM met to devise appropriate consensus strategies for implementing safety standards. As a result of this work, in the Spring of 1970, the BRH developed a performance standard for microwave ovens that limited emissions to l mW/cm2 for new ovens, and 5 mW/cm - for old ovens, measured 5 cm from the unit with a standard water load [12].

This standard was based on the rationale that 5 cm was about as close as the human eye would normally come to the oven. Moreover, field intensities decrease by the inverse square of distance. Thus, a 1 mW/cm2 emission at 5 cm from the surface of the oven would generally result in a 10 W/cm2 exposure level at SO cm- the closest a person might approach the oven and receive a whole body exposure. Thus, the 1968 emission standard for microwave ovens (still in effect) provided the same degree of protection or better for whole body exposure as the (then) Soviet occupational standard [4].

Other legislative initiatives addressed hazards in the workplace. In 1970, the U.S. Congress passed the Occupational Safety and Health Act (Public Law 91- 596), which addressed workplace hazards, including hazards associated with sources of ionizing and nonionizing radiation. The law established the Occupa- tional Safety and Health Administration (OSHA) and gave it the responsibility of

2

drafting and implementing the appropriate regulations.

This law allowed the OSHA to adopt any national consensus standard on an interim basis, until it could develop per- manent protective measures. Further, OSHA could request advice on workplace hazards from the National Institute of Oc- cupational Safety and Health (NIOSH), part of the Department of Health, Educa- tion, and Welfare. The NIOSH, in turn, could study workplace hazards upon request by OSHA, and draft criteria documents with recommendations to address the hazard.

Thus, in 1971, the OSHA adopted the 1966 ANSI standard on RF radiation (C9S.l-1966) as the national guideline to determine safe working environments. In- terestingly, though the ANSI RF standard has been revised several times since 1966, the OSHA retains the 1966 version.

Still other government efforts addressed RF safety issues in the general environment. In response to increasing environmental concerns, President Nixon created the Environmental Protection Agency (EPA) in 1970, through Reor- ganization Plan No. 3. Under this plan, Federal radiation protection guidance, previously developed under the Federal Radiation Council Authority (Public Law 86-373), was transferred to the EPA. This Plan required the EPA Administrator to “Advise the president with respect to radiation matters [ionizing and nonionizing], directly or indirectly affecting health, [and provide] Guidance for all Federal agencies in the formulation of radiation standards and in the establishment and execution of programs of cooperation with the States.” Also during this period, responsibility for emission standards for microwave ovens and other appliances was shifted from the BRH to the Food and Drug Administration.

In developing radiation exposure guidance, the EPA Administrator is required to consult with the National Council on Radiation Protection and Measurements (NCRP) and other expert organizations. Once such guidance has been approved by the President, appropriate Federal agencies would be responsible for its imple- mentation [ 171.

To address its new responsibilities, the EPA began an extensive environmental monitoring campaign to assess and char- acterize the public’s exposure to RF radiation. Results of these efforts were published in the 1980s. Staffing and

budget concerns and difficulties with inter-agency cooperation hindered early EPA efforts in developing radiation protection guidance [36]. However, in 1982, the EPA published its “Advance Notice of Proposed Recommendations (ANPR),” in the Federal Register on radiation protection [37]. This notice announced the Agency’s intention to develop radiation protection guidance for federal agencies and invited public comment on these proposed actions. Then, in 1986, the EPA published in the Federal Register a set of proposed alternatives for controlling public exposure to RF radiation [32]. The extensive public and interagency com- ments generated by this proposed guidance led the EPA to delay further activity in issuing radiation protection guidances until the mid 1990s [33].

By the early 1970s, RF radiation issues had been well studied, both in the scientific and regulatory arenas. Biological effects of RF radiation emitted by radar and telecommunications equipment, microwave ovens, and other sources had been studied; and theoretical and experimental research had supported safety limits adopted in the United States and other Western countries. Work by Soviet and Eastern Block researchers continued to raise concerns about possible health hazards from low-level RF radiation, but this research remained unpersuasive to West- ern scientists because of numerous technical deficiencies. By the early 1970s, the scientific evidence indicated that the pri- mary hazards from excessive exposure to RF radiation were thermal in nature, and that the hazards had been well charac- terized and effective safeguards developed. Events soon shifted attention from RF radiation to lower-frequency fields, and from thermal to athermal concerns. More recently, budgetary restrictions have delayed indefinitely any further EPA efforts on RF standards development.

A Question of Cancer By 1970, regulations had been drafted

by the BRH, in cooperation with industry, to address microwave oven safety. How- ever, some safety concerns still remained. A consumer activist group, the Con- sumer’s Union, recommend against the use of microwave ovens because of safety concerns [SI. In March of 1973, the issue received attention by the Congress as a result of Commerce Committee hearings on the effectiveness of the Radiation Con- trol for Health and Safety Act of 1968.

July/August 1996 IEEE ENGINEERING IN MEDICINE AN0 BIOLOGY 27

Little resulted from the hearings apart from the statement by some members of Congress that more knowledge is needed about microwave bioeffects. During the early 1970s. there was considerable military research on defense applications of microwaves, some of which was disclosed in the public media [5].

In March of 1976 came the disclosure that the U S . embassy in Moscow was being irradiated with microwaves by the Soviets. The irradiation was first detected by U.S. Navy Intelligence technicians during a routine electronic sweep at the embassy in 1953 [20]. By 1963, after extensive monitoring, the State Department concluded that the microwave irradiation was probably deliberate and not acciden- tal. In this period, the DOD began a clas- sified project (Project Pandora) to assess the potential bioeffects, if any, of the microwave signals. Experiments were carried out on laboratory animals using replicated “Moscow” signals. The microwave signals were weak, with average power densities of a few 1W/cm2 or less -several orders of magnitude below the U.S. exposure standard. Subsequently, the State Department instituted its own electronics monitoring efforts at the embassy. Then, in November of 1975, the U.S. ambassador to Moscow was reported ill with leukemia.

Ionizing radiation is a well known cause of leukemia; but the public and many professionals have confused ionizing with non-ionizing radiation. This con- fusion was underscored when a State Department physician likened microwave radiation to ionizing radiation in his letter to the ambassador. Speculation arose whether the microwave radiation might have caused the ambassador’s leukemia.

A team of physicians and technical consultants was soon assembled and flown to the Moscow embassy to analyze the health records of embassy personnel. The team reported that the exposure to microwave radiation at the power levels at the Embassy was not associated with any health effects. It also recommended that a full biostatistical review be done on all embassy personnel back to 1953, when the irradiation was first discovered, and that embassy staff should be briefed on the radiation. In March of 1976, the ambassador called a special meeting of embassy personnel and revealed the history of the microwave irradiation of the embassy. Shortly thereafter, he himself was diag- nosed with leukemia.

The State Department contracted with the Department of Epidemiology at the Johns Hopkins University [20], and the study began in June of 1976. The investigators examined all morbidity and mortal- ity data from 1,827 State Department employees and their dependents who worked at the Moscow embassy during the period 1953 - 1977. Another 2,561 employees who had worked at other em- bassies during the same period and their dependants were used as controls. The investigators concluded that personnel serving at the Moscow embassy over this period suffered no ill effects from the microwaves beamed at the chancery [21].

In the late 1960s, the U.S Navy proposed a submarine communications system, originally named Project Sanguine. which would operate in the extremely- low-frequency (ELF) range of the electromagnetic spectrum [18]. The project entailed the construction of a vast array of underground cables situated in Northern Wisconsin and Michigan’s Upper Penin- sula. The design was later changed from an underground array to an overhead array, significantly changing the near-field characteristics, and the name was changed to Project Seafarer. Public outcry resulted in several suspensions of the project, though construction was eventuaIIy com- pleted in the 1980s.

To document possible environmental impacts of the system, the U.S. Navy conducted a research program, between 1969 and 1977, funded at $8 million. In 1985, the U.S. Navy sponsored a review of the post- 1977 literature on ELF bioeffects. The report concluded that the ELF fields resulting from Project Seafarer would be unlikely to have adverse health effects to humans or the environment [19j. How- ever, the controversy engendered by the program gained widespread publicity and raised public concerns about potential health effects from low-frequency electromagnetic fields. Subsequent events served to heighten this concern.

In 1975, the New York State Public Service Commission held common-re- cord hearings as a part of its environmental impact study of two proposed 765-kV transmission lines. A settlement of litigation seeking to stop one of the lines led to the formation of the New York State Power Lines Project, a five year, $5 million program, funded by New York State utilities and administered by the New York State Department of Health [22j. The final report found no evidence

to support adverse health effects from the electric and magnetic fields associated with the line [29].

Then, in 1979, an epidemiological study by Wertheimer and Leeper was published that suggested that a link existed between exposure to magnetic fields from neighborhood power distribution systems and childhood leukemia [23]. Previously, most bioeffects research using 60 Hz fields had focused on the strong electric fields generated by high voltage transmission lines. After the publication of the Wertheimer-Leeper study, public and scientific attention shifted to cancer from power-frequency magnetic fields, particu- larly fields from neighborhood distribution lines.

The Congress took up these issues in 1987 with hearings before the House Committee on Interior and Insular Affairs, Subcommittee on Water and Power Re- sources [24j. Subsequent hearings by this committee [25] and the House Committee on Science, Space, and Technology, Sub- committee on Natural Resources, Agri- culture Research, and Environment [26,27], led to passage of the Energy Pol- icy Act of 1992 (Public Law 102-486).

This Act created the National EMF Research and Public Inforniation Dis- semination (RAPID) Program, a 5-year, $65 million program to administer, coor- dinate, and support research on power frequency electric and magnetic fields [48]. Under the Program, the Department of Energy has responsibility for engineering research, while the National Institute of Environmental Health Sciences has responsibility for health effects research. The funding for the program is divided equally between the federal government and private industry [28].

Other federal agencies maintain research programs in power frequency electric and magnetic fields. The U.S. Navy continues to support bioeffects research from ELF fields in connection with the submarine communication program. Re- search into siting high voltage transmission lines is funded by the DOE and is administered by the Bonneville Power Administration (BPA) [46, 471. The De- partment of Health and Human Services (HHS; formerly the Department of Health, Education and Welfare, HEW) also supports bioeffects research, which includes extramural and intramural programs at the National Cancer Institute (NCI) and the NIEHS [35].

Research in power frequency electric

28 IEEE ENGINEERING I N MEDICINE AND BIOLOGY Jdy/August 1996

and magnetic fields is also supported by private institutes such as the Electric Power Research Institute (EPRI), autility- industry supported research organization. Other industry organizations, such as the Edison Electric Institute (EEI) and the Electromagnetic Energy Policy Alliance (EEPA), provide communications on health concerns related to power frequency fields, and (in the case of EEI) sponsor research.

Over the last 15 years, considerable research has been undertaken on power frequency fields and their bioeffects. In- teresting interactions of biological systems with electric and magnetic fields at power frequencies have been reported. However, no carcinogenic effects of these fields have been conclusively demonstrated. As with early bioeffects research involving RF radiation, nearly 40 years ago, no exposure metric has been identi- fied that can be associated with well-docu- mented effects from weak fields. (Many effects are well known to result from exposure to strong electric and magnetic fields, for which the field strength is an appropriate metric of exposure). Until such an exposure metric is demonstrated and accepted, much 60-Hz bioeffects research will continue to be controversial, in part because of technical problems with the studies, and in part because of lack of rationale for the existence of effects at low exposure levels [34,39].

A more recent public issue is potential health effects of cellular telephones. Since beginning commercial service in 1983, the cellular telephone industry has been one of the fastest growing segments of the U.S. economy, growing from 100,000 subscribers at the end of 1984 to more than 2 million subscribers by the end of 1991 [301. By the end of the 199Os, it is esti- mated that cellular service will expand to over 60 million users, nationally [3 I].

Cellular telephones operate at frequencies close to 850 MHz. They transmit at low power levels (0.6 watts for hand-held units) but, while in use, are located very close to the user’s head. This has naturally led to concerns about potential health effects.

One particular concern has been brain cancer from use of a cellular phone, fol- lowing a widely publicized lawsuit filed by the husband of a woman who died of the disease. The suit was later dismissed by a federal court for lack of evidence, but the issue remains controversial.

To address health concerns, govern-

ment agencies and the telecommunications industry have launched research programs to assess the potential bioeffects of emissions from wireless devices. The telecommunications industry has been working with federal agencies since the 1970s to develop RF dosimetry techniques and to assess the potential bioeffects resulting from cellular telephone use. Additionally, in the early 1990s, the telecommunications industry launched a $20 million program to examine potential health effects of wireless communications technologies [38]. The FDA maintains ongoing research programs to develop effective dosimetry techniques for RF radiation exposure measurements. The National Can- cer Institute is currently conducting an epidemiological investigation of brain cancer in adults associated with use of cellular telephones, and other investigators are studying the issue under industry support.

Another issue is potential interference from portable communication devices with medical equipment, which is being studied at the Rockville, MD laboratories of the Center for Devices and Radiologi- cal Health of the FDA.

Standards development continues. The first ANSI RF standard, C95.1-1966, was updated in 1974 with only minor changes (C95.1-1974). However, research conducted through the 1970s resulted in a substantial revision to this standard in 1982 to take into account the fact that RF energy absorption in man is frequency-dependent. This research also established a defensible metric for exposure to RF radiation, the Specific Absorption Ratio (SAR). The ANSI and other standards are based on the conclusion of the standards setting committees that behavioral disrup- tion in laboratory animals is the adverse effect occurring at the lowest exposure level [40]. In 1992, the ANSI standard was again revised [41]. The latest version now sets two exposure standards: one for “controlled environments,” such as for occupa- t i ona l s e t t i ngs , and ano the r fo r “uncontrolled environments,” such as for the general public. These adjustments es- sentially bring the ANSI standard into line with the two-tier philosophy of the RF radiation guidelines developed by the Na- tional Council on Radiation Protection and Measurements.

Acknowledgments The author is grateful for the generous

assistance provided by Mr. Norm Sandler

and Dr. Quirino Balzano, with Motorola Corp; Dr. Howard Bassen, with the Food and Drug Administratoin; Dr. George Carlo, with Wireless Technology Re- search; Dr. Robert Cleveland, with the Federal Communications Commission; Dr. Arthur Guy, with the University of Washington; Mr. Nobert Hankin, with the Environmental Protection Agency; Ms. Janet Healer, with the National Telecom- munication and Information Administra- toin; Dr. Thomas Koval, with the National Council on Radiation Protection and Measurements; Dr. Jack Lee, with the Bonneville Power Administration; Dr. John Osepchuck, with Raytheon Corp; Dr. Herman Schwan, with the University of Pennsylvania; Dr. Charles Susskind, with the University of California, Berkeley, and the San Francisco Press; Mr. David Sawdon, with IBM; and Dr. John Wil- liams, with Science Applications Interna- tional Corp. (SAIC). Thanks to Dr. Dennis Hadlock for initiating the author’s study in EMF health effects issues.

Special recognition goes to SAIC and especially to Ms. Patricia Wherley, Ms. Donna Frost, and Mr. Robert Whiteside for providing the support to make possible the author’s research in EMF health effects. Thanks also to Ms. Yvonne Quin- ney, with SAIC, for outstanding graphics assistance. Special thanks to Dr. Kenneth Foster, with the University of Pennsylva- nia, for support and guidance of the author’s study in EMF health effects.

Stephan P. Albert Bren (M) received his B.S. degree in Physics at the University of Washing- ton ( I 986) and the M.S. degree in Electrical En- gineering at Washing- ton State University (1991). Since 1992, he

has worked for SAIC in several capacities, first as an analyst for the Department of Energy and, currently, as a local area net- work engineer for Madigan Army Medi- cal Center. Mr. Bren also provides technical assistance to SAIC on safety and health issues concerning electromagnetic fields. He can be reached at: Madigan Army Medical Center, SAIC/CHCS, HSHJ-IMA Building 9040A, Tacoma, WA 9843 1-5000, e-mail: Stephan_Bren@ smtplink.mamc.amedd. army.mi

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30 IEEE ENGINEERING IN MEDICINE AND BIOLOGY July/August 1996

Documents

Historical introduction to EMF health effects