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Research on Power-Frequency Fields: Completed Under the Energy Policy Act of 1992 EPACT COMMITTEE REVIEW OF COMPLETED PROJECTS DOE Engineering Projects The present EPACT Committee received 11 of 12 engineering reports funded by EMF-RAPID as contracts in time for inclusion in the committee's final report. The 11 engineering reports are listed in table 1.
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Research on Power-Frequency Fields: Completed Under the Energy Policy Act of 1992 Table 1—EMF-RAPID Funded Engineering Projects Reviewed by EPACT Committee # Organization Title Work Done 1 Electric Research & Management, Inc. "Development of Recommendations for Guidelines for Field Source Measurement" Identification of set of MF characteristics that can be measured; development of protocols for measurements of fields from appliances on a laboratory test rig and from on-site measurements in complex field environment; gathering of data for specific appliances and environments 2 Magnetic Measurements Co. "Recommendations for Guidelines for Environment-Specific Magnetic Field Measurements" Identification of set of MF characteristics that can be measured; development of protocols for characterizing human activity patterns and using information to estimate personal exposures in defined areas; application of protocol in pilot studies 3 Enertech Consultants "Environmental Field Surveys" Surveys of MF levels in various environments 4 T. Dan Bracken, Inc. "Recommendation for Guidelines for EMF Personal Exposure Measurement" Identification of set of MF characteristics that can be measured; development of measurement protocols 5 T. Dan Bracken, Inc. "Development of an EMF Measurements Database" Development of database to serve as repository for MF exposure data 6 Enertech Consultants, Inc. "Survey of Personal Magnetic Field Exposure" Survey of average field exposures of 1000 randomly selected people in the United States 7 National Institute for Occupational Safety and Health "Hazard Surveillance for Workplace Magnetic Fields" "Walkaround" surveys of MF characteristics in large number of workplace environments
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Research on Power-Frequency Fields: Completed Under the Energy Policy Act of 1992 # Organization Title Work Done 8 IIT Research Institute and Commonwealth Associates "Evaluation of Field-Reduction Technologies" Evaluation of field-reduction strategies for several kinds of sources, including cost estimates for various strategies for each kind of source 9 University of Washington "Characterization of Exposures to Extremely Low Frequency Magnetic Fields in the Office Environment" Spot and personal exposure-meter measurements of MFs in office environments and homes 10 EM Factors "Assessment of Human Exposure to Magnetic Fields Produced by Domestic Appliances" Comparison of information from questionnaires with data gathered from personal exposure meters for a group of 40 women in England to determine degree of correlation 11 Center for Risk Management, Resources for the Future "Risk Dimensions of the EMF Problem" Views of author on nature of power-frequency magnetic field risk [Note: although funded through the EMF-RAPID engineering program, this project did not involve actual engineering research] 12 T. Dan Bracken, Inc. "Source and Exposure Prediction Model Development" Project not completed in time for committee review
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Research on Power-Frequency Fields: Completed Under the Energy Policy Act of 1992 Committee evaluations of the projects follow: Project 1: "Development of Recommendations for Guidelines for Field Source Measurement" (Electric Research and Management, Inc). This project (ERMI 1997) involved identifying the set of field characteristics that should be measured for interpreting the results of biologic and human-exposure studies and for focusing any future attempts at field management. The investigators also proposed methods for characterizing MF sources on the basis of MF strength at a fixed distance, dominant field components, intermittency, spatial attenuation, and polarization. In addition, the report describes protocols for measurements of fields from appliances and for on-site measurements of fields in a complex exposure environment, such as an office or factory. Examples of these measurement protocols were provided, and useful data were presented on the MFs measured in the vicinity of 20 appliances commonly used in homes and offices. Project 2: "Recommendations for Guidelines for Environment-Specific Magnetic-Field Measurements" (Magnetic Measurements Co). This study (Magnetic Measurements 1998) attempted to anticipate every aspect of power-frequency MFs that might be related to biologic or human health effects and suggested the equipment, measurement protocols, data-management and analysis procedures, quality-control measures, and reporting procedures that should be used for characterizing the MF environment in any given occupational, public, or residential setting. Methods are described for characterizing human activity patterns and for using that information to estimate personal exposures to sources in a well-defined area. For that purpose, each study area is to be divided into sharply defined microenvironments within which the fields and activity patterns can be characterized with reasonable precision. The protocol was tested in three pilot studies involving a day-care center, a metal fabrication plant, and a grocery store. The field-characterization procedures described in the report would be extremely difficult and expensive to perform on a large number of people in any specific occupational or public environment. In addition, the results of other studies have not shown a clear correlation between activity patterns and MF exposure from appliances (see report of project 10). Project 3: "Environmental Field Surveys" (Enertech Consultants) The objective of this project (Enertech Consultants 1996) was to perform preliminary surveys of the levels and characteristics of MF exposures in residential, public, and occupational environments. Measurements were made of time-weighted average 60-Hz MFs and harmonic fields in grocery stores, schools, office buildings, hospitals, and machine shops. For each type of environment, four sites were studied; 11 sites were in California, and nine were in Massachusetts. Area surveys of the MFs indicated an approximately three-fold variation in the average exposure levels in the five types of environment; the measured values being 0.193 microtesla (µT) in grocery stores, 0.142 µT in machine shops, 0.127 µT in hospitals, 0.083 µT in schools, and 0.072 µT in office buildings. The highest occupational exposures were found for welders in machine shops (0.52 µT), butchers in grocery stores (0.41 µT), and clerks and cashiers in grocery stores (0.40 µT). Exposures were about the same for students, visitors in hospitals, and
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Research on Power-Frequency Fields: Completed Under the Energy Policy Act of 1992 professionals in office buildings—all 0.08–0.09 µT. The main sources of area fields were found to be net electrical currents in wiring, office equipment, milling and welding equipment, fluorescent lights, electrical panels in machine shops, and powerlines. It also was observed that DC and AC fields generally are not aligned (either parallel or perpendicular) to each other, third and fifth harmonics of MFs from various sources are generally the largest (with amplitudes that are, respectively, about 30% and 10% of the 60-Hz primary field amplitude), and the polarization of MFs is generally random. Funding limitations, and the unwillingness of people at some sites to participate reduced the type and number of sites surveyed. Apparently because of an agreement with site-owners and operators not to identify the sites, there is a minimal description of the sites. For example, there is no indication of whether the facilities were modern or old, and no information on the types of hospitals or office buildings. Project 4: "Recommendations for Guidelines for EMF Personal Exposure Measurement" (T. Dan Bracken, Inc). The report on this project (T. Dan Bracken 1997a) described protocols for an exhaustive assessment of personal exposures to power-frequency fields. An extensive discussion is given of potentially relevant field parameters, measurement equipment, technical problems associated with MF measurements, measurement protocols, time-activity monitoring, data management and analysis, and quality control. The report recommends that MF measurements record the resultant field (the square root of the sum of the squares of three orthogonal field components) rather than the magnitude of the field (which includes phase information but is more difficult to measure). For EFs, the investigators regard measurements at the body surface as having reasonable precision, but they recognize that the magnitude of a field depends in a complex manner on the orientation of the subject relative to the source of the field. The report also discusses the onerous and expensive nature of time-activity recording in diaries carried by the study participants. Some limited pilot results were obtained by using high-school physics students and employees at an instrument-manufacturing facility as subjects, but there were not enough data to assess the value of time-activity recording. Project 5: "Development of an EMF Measurements Database" (T. Dan Bracken, Inc). This project (T. Dan Bracken 1997b) involved the development of an MF measurements database that can serve as a repository for data and reports generated in a wide variety of studies on this subject. An Internet site was established to make the data readily available to users. Three types of data can be entered into the database: a "metadata" file that describes the origin, development, and physical content of a data set, a "data products" information base that contains actual measurement data and a "reports information" base that contains the text, tables, and figures describing the results of a study. The functions of the MF database were illustrated by entering a small set of data on 20 persons, 18 of whom were federal office workers. Although the report clearly describes the procedures for recording MF exposure data and making them available to users, there have apparently been no efforts to use the procedures for archiving the data obtained in large surveys of personal MF exposure, such as project 6, below. There is no information as to how much the database has been used, how satisfied any users are, and whether any problems have been encountered in its use.
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Research on Power-Frequency Fields: Completed Under the Energy Policy Act of 1992 Project No. 6: "Survey of Personal Magnetic Field Exposure" (Enertech Consultants) The goal of this project (Enertech Consultants 1998a,b), which was the most comprehensive study undertaken as part of the EMF-RAPID engineering program, was to analyze average exposures to power-frequency MFs (and harmonics up to 1,000 Hz) of the US population on the basis of a randomly selected cross section of 1,000 people. The study used a combination of information obtained by questionnaires and by 24-h continuous measurements recorded with a compact MF exposure meter (the EMDEX). Exposures of people in all the major geographic regions of the United States at home, work and school and during travel were measured using a study design that was balanced on the basis of the gender and age of the participants. Before the main study, a pilot study (phase I) was performed with about 200 participants. The results of the phase I study formed the basis of a number of important decisions on the phase II study protocol and the personal exposure meter to be used (the EMDEX-MATE with permanent memory and 10-min data summaries). The primary findings of the large phase II study with approximately 1,000 participants were: The geometric mean value (and 95% confidence interval) recorded for a 24-h exposure is 0.089 (0.085–0.093) µT, with a lognormal distribution of data over the range 0.03–0.30 µT. Percentages of the population exposed to 24-h average field levels greater than 0.2, 0.3, 0.5, and 1.0 µT are 14.3%, 6.3%, 2.4%, and 0.5%, respectively. Those percentages are higher by about 35% than those observed in the previous Electric Power Research Institute 1,000-home study, in which "spot measurements" of MF levels were taken in various rooms of the homes (usually at the center of a room). It is reasonable that the personal exposure meters used in the present study would give higher average exposure levels in that the people wearing the exposure meters often came into contact with or were close to appliances that generated relatively large power-frequency MFs. It should be noted that 24-h exposure includes occupational exposures, which can be higher than residential ones. Little difference was observed in MF exposure between men and women, and the highest exposure was of working-age people (0.097 µT), followed by retirees and preschool children (0.080 µT) and school-age children (0.076 µT). Little geographic dependence was found in the average MF exposure, with the largest geometric mean value being observed in the Northeast (0.100 µT), followed by the West and Midwest (0.087 µT) and the South (0.086 µT). About 25% and 9% of the population were exposed to fields greater than 0.4 µT and 0.8 µT, respectively, for more than 1 h per day. About 1.6% of the population were exposed to fields greater than 100 µT at least once in a 24-h period. The highest average exposure occurred "at work" (0.103 µT), followed by "on travel" (0.096 µT), "at home not in bed" (0.080 µT), "at school" (0.064 µT), and "at home in bed'' (0.052 µT). The average field exceeded 0.2 µT for 21%, 14%, and 3.5% of the people in the categories "at work", "at home not in bed", and "at school", respectively.
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Research on Power-Frequency Fields: Completed Under the Energy Policy Act of 1992 For the "at work" period (8 h averages), the highest exposures were among electrical workers (0.16 µT), followed by food, cleaning, health, and protective service workers (0.16 µT), technical, sales, and administrative workers (0.11 µT), management and professional specialty workers (0.10 µT), precision production, crafts, equipment-repair workers, operators, fabricators, and laborers (0.09 µT), and farming, forestry, and fishing workers (0.05 µT). For the "at home" period, the highest average exposures were experienced by people living in standard (fewer than 5 floors) apartment buildings (0.11 µT) and duplexes (0.10 µT), followed by tall (more than 5 floors) apartment buildings (0.09 µT), single-family homes (0.07 µT), and mobile homes (0.05 µT). The highest average exposures were in small (less than 1,000 ft2) dwellings (0.08 µT), followed by medium (1,000–2,000 ft2) dwellings (0.07 µT), and large (more than 2,000 ft2) dwellings (0.06 µT). Bedroom exposures were greatest when the bedroom was on the second or higher floors (0.06 µT), followed by the first floor (0.05 µT) and the basement (0.05 µT). Higher average exposures were observed in dwellings with metal pipes (0.08 µT) than with plastic pipes (0.05 µT). "At home" average exposures were inversely related to the distance of the nearest overhead powerline (less than 25 ft, 0.09 µT; 25–50 it, 0.08 µT; 50–150 ft, 0.06 µT; and more than 150 ft, 0.06 µT). Exposure also varied with the type and number of powerlines; the highest exposures were associated with transmission lines (0.1 µT) and two three-phase primary distribution lines (0.11 µT). Lower exposures were associated with a single-phase primary line (0.07 µT) and a two-phase primary line (0.05 µT). Many sudden field changes were recorded where the field value was more than 50% different from the average of two consecutive readings. The percentage of people experiencing more than 10 sudden field changes of over 1.0 µT, over 0.5 µT, and over 0.25 µT are over 30%, over 50%, and over 90%, respectively. Those data undoubtedly reflect intermittent exposures from local sources (such as appliances) or other types of power switching in the environment of the exposed person. Three aspects of the study design reduce the ability to generalize from the results that were obtained: A low participation rate (28.4%) based on consent forms returned relative to the number of initial telephone contacts. The percentage of those age 17 yr or under studied in this project (8.2%) is only onehalf the percentage of those age 17 yr or under in the US population (16.6%). All measurements were made in the coldest months of the year (November to March). Project 7: "Hazard Surveillance for Workplace Magnetic Fields: I. Walkaround Sampling Method for Measuring Ambient Field Magnitude and II. Field Characteristics from Waveform Measurements" (National Institute for Occupational Safety and Health). This study (NIOSH 1998) provided a description of procedures for characterizing occupational MF exposures with a portable data logger (the EMDEX-II) and a waveform-capture system that enables evaluation of the field magnitude, frequency spectrum,
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Research on Power-Frequency Fields: Completed Under the Energy Policy Act of 1992 polarization, spatial orientation, and total harmonic content. The walkaround surveys with the portable exposure meter were conducted in 62 facilities, ranging from a small print shop to a large oil refinery. The results of the surveys demonstrated two aspects of workplace exposures: the electric-power consumption in a given facility cannot be used reliably as an indicator of worker exposures to MFs, and the Standard Industrial Classification is not a reliable tool for predicting worker exposures. The waveform-capture system was used in six diverse industries: aluminum extrusion, aluminum-framed filters preparation, plastic-polymer production, liquid air separation, cement production, and pharmaceutical manufacturing. A problem that was encountered during these measurements was an effect on the waveform resulting from motion of the field probe. An algorithm was developed to correct for this motion, but the algorithm was not very reliable. On the basis of 59 waveform measurements, the recorded fields showed significant second, third, and fifth harmonics, with a total harmonic distortion of about 15%. Project 8: "Evaluation of Field-Reduction Technologies" (IIT Research Institute and Commonwealth Associates) This study (IIT 1997) involved an in-depth evaluation of exposure-mitigation procedures for nearly all common sources of human exposure to power-frequency MFs, including powerlines and substations, electric-power service connections in homes and businesses ("customer-side" power distribution), appliances and machine tools, and electric transportation systems. Four types of reduction were considered: self-cancellation methods, such as split currents moving in opposite directions or magnetic dipoles with oppositely directed vector orientations; active cancellation using bucking coils; field cancellation by inducing eddy currents in nearby metal structures; and shielding with ferromagnetic materials. For the various field-reduction methods, cost estimates were provided on the basis of required materials and labor, project costs (including land purchase, permits and licenses, and engineering surveys), and life-cycle costs (management and operations, interest on leases, property taxes, and insurance). The conclusions of this study were as follows: For powerlines, unbalanced current is the main source of MFs. This is the case for the MFs from distribution lines and for household wiring. A variety of field-reduction methods can be used, including balancing the current load, using splitphase configurations, compacting conductor bundles, placing cables underground, and decreasing the current while increasing the voltage to maintain the same load. Customer-side power distribution sources that were evaluated included electric service panels, transformers, switchgear, and wiring. Field-reduction methods include correcting the return-current imbalance and avoiding ground-current loops, using metal conduits, installing shielding for panels and switchgear, the use of shielded and twisted-pair wiring, and using three-conductor wires. The overall cost of upgrades in wiring can be 50% to 100% greater than the cost of standard wiring. In appliances and machinery, the main sources of MFs are small motors, resistive heating elements, meters, transformers, and wiring. A variety of methods are generally available to reduce a stray field at little cost, including split-return currents, shunt connections, and toroidal coil winding in transformers. However, some
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Research on Power-Frequency Fields: Completed Under the Energy Policy Act of 1992 machinery, such as welding and melting machines and electric furnaces, pose difficult problems in achieving field reduction. For electric transportation systems, the main sources of stray MFs include motors and unbalanced currents. These sources can lead to very high MF levels in passenger cars (1.0–10.0 µT at 60 Hz). However, significant field reduction can be achieved by using dual overhead-trolley connections, return current wires that are close to the supply wires, and DC currents. Shielding with ferromagnetic materials is not practical, because of the added weight. Project 9: "Characterization of Exposures to Extremely Low Frequency MFs in the Office Environment" (University of Washington Master's Thesis in Environmental Health prepared by P. Hogue). The purpose of this study (Hogue 1995) was to characterize exposures to power-frequency MFs in an office environment on the basis of data obtained from 70 workers in a single company at 12 sites. Comparisons were made between spot measurements of fields in the work location and exposure data obtained with a personal exposure meter, the EMDEX Lite. Exposure measurements were made for 24 h, thereby obtaining additional useful information on nonwork exposures of each subject. The primary findings in this study were as follows: The arithmetic mean value of the MF measured with a personal exposure meter for the office environment was 0.17 µT; for nonwork exposures (mostly at home), it was 0.14 µT. From the cumulative data, the average office exposure during a typical workday contributed about 35% of the total average 24-h exposure (8-h average). For office workers, the within-day variability was greater than the between-day variability. The greatest variability in exposure levels was observed between subjects. The exposure data were found to be quite stable when measurements were collected at time intervals separated by up to 62 d. No significant variation in the office exposure levels was observed as a function of time of day. Spot measurements of the MF levels were found to correlate well with measurements made with the EMDEX Lite personal exposure meter; spot measurements were able to account for about 65% of personal work-exposure variability. Project 10: "Assessment of Human Exposure to Magnetic Fields Produced by Domestic Appliances" (EM Factors) The primary purpose of this study (EM Factors 1996) was to assess the reliability of estimating MF exposure with questionnaire data on electrical-appliance use in the home. Predicted exposures based on questionnaire data and measurements of the MFs produced by various appliances were compared with personal-exposure data acquired with an EMDEX-II meter worn at the waist. The study, conducted in Avon, England, involved 50 women; 805 measurements were made on fields from 50 types of household electrical appliances. The following is a summary of the major findings in this study:
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Research on Power-Frequency Fields: Completed Under the Energy Policy Act of 1992 No correlation was found between measurements of fields produced by appliances and actual exposures measured with an EMDEX meter. The personal-exposure data correlated reasonably well with an exposure model that included measured average fields in the kitchen and bedroom, independently of appliance contributions to the variability in the measured fields. Similarly, peak exposures were unrelated to the use of any appliance. The results of this study indicate that questionnaire data on the amount of time that various appliances are used cannot be relied on as a basis for estimating exposure to the power-frequency MFs emanating from household appliances. A model was developed that accounts for the effects of some commonly used appliances on the 90th percentile of peak exposures. Three appliances that were used more than 15 min/d at operating distances of less than 100 cm and that fit this model were a microwave oven, a conventional oven, and an electric cooker. Electric blankets were not included because only four of the 50 subjects used them. The model also was found to be applicable to characterizing exposures to fluctuating MFs at the 90th percentile of peak values. The median exposure of the subjects in this study was one-fourth to one-third of the exposures found in a previous large study of a comparable nature in the United States. This difference is probably related to the use of 240-V line voltages in the UK rather than the 120-V used in the United States, with correspondingly lower currents that give rise to lower MFs. Also, the report notes that electricity in the UK is quite expensive, and therefore is used more sparingly than in the United States. Project 11 "Risk Dimensions of the EMF Problem" (Center for Risk Management, Resources for the Future) The report of this project (Florig 1995) was delivered to the committee in connection with the engineering program, but it is actually a risk-analysis report rather than an engineering report. The objective of the project was to use epidemiologic information available up to 1995 to put the potential cancer risk posed by MF exposure into the broader context of risks posed by other environmental agents. The report is the opinion of one person, who also attempted to analyze the impact of information on EMF-exposure health risks on public policy and regulatory restrictions on exposure. The author apparently believes that power-frequency magnetic fields pose a childhood health hazard and that MF studies might be biased toward null results. He criticizes expert panels and government agencies in their handling of MF issues. This committee notes that the literature base on which this report was developed is now out of date, and therefore questions the utility of the conclusions of the author on cancer risk related to MF exposure. Summary EMF-RAPID committed about $2.7 million to engineering studies an amount that is 6.6% of the total budget of $41 million. The overall value of what has been accomplished in the 11 engineering projects funded as part of the EMF-RAPID program is questionable. The projects were commissioned without any convincing evidence of specific linkages between low-level MF exposure and human health effects. As a result, the engineering projects were designed to establish field-measurement and management
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Research on Power-Frequency Fields: Completed Under the Energy Policy Act of 1992 technologies for ill-defined possible future discoveries of biologic effects of power-frequency fields. There is a considerable degree of overlap and repetition among several of the individual projects. Many of the projects have "the cart before the horse", in the sense that they anticipate all possible field parameters of potential relevance, without good reason to focus on any specific one. A considerable amount of money has been spent to fund work that will probably never be used. Furthermore, the work was done concurrently with other EMF-RAPID studies, so the results of the engineering projects could not be used in the biology projects. Three projects (projects 1, 2, and 4) had as goals the establishment of MF measurement methods and protocols. In the absence of real knowledge of what field properties might be of concern, a large number of possible field metrics were evaluated in these studies. A large amount of detail was provided about how to characterize a wide variety of field properties. However, in the absence of any established health effects associated with EMF exposure, it is not evident which, if any, of the measured field parameters are relevant. A fourth project (project 5) was concerned with the establishment of a database to serve as a "repository" for data generated in engineering studies of MF environments. Again, a significant effort has gone into the creation of the structure of this database without knowledge of the specific issue that the data will address. In addition, the large sets of individual exposure data obtained under funding from the EMF-RAPID program (projects 3, 6, 7, 9, and 10) have not been entered into the database at the time of this review. The measurement protocol and database projects probably will never be needed. At the least, this work would have been much more efficiently carried out after the establishment of a specific biologic effect. The five individual-exposure data projects (projects 3, 6, 7, 9, and 10) involved determinations of levels of MF exposure in a variety of specific environments (household, work, office and so on). A large amount of detailed data was collected, but it is not likely that the bulk of it will ever be used. The overall conclusion from this work is that field exposures do not vary a great deal from one type of environment to another. On the basis of personal-exposure measurements, the time-weighted-average (TWA) MF levels to which most members of the US population are exposed are in the range of 0.1–0.2 µT. In that range, exposures at work and in some transportation vehicles are generally greater than those experienced in the home. TWA exposures above 0.2 µT are relatively infrequent among the general population, although occupations that involve working in close proximity to industrial machinery and business machines can lead to TWA exposures in excess of 0.4 µT. Of the 11 projects, only one (project 8), which addressed field-reduction methods for a variety of sources and made comparisons of costs for various levels of reduction, provides information on what can be done to mitigate MF exposure if it is ever found necessary. This work could also be of some value with regard to field-reduction applications unrelated to health effects. Some of the methods described for reducing fields from powerlines are being used in new installations. It was also noted by the committee that EPRI has funded work on methods for reducing fields from powerlines and other sources. It is not difficult to envision MF measurement studies that could be done to provide large volumes of data that might be useful if some causal effect is determined to exist. But to provide substantial funding for such studies without specific guidance from
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Research on Power-Frequency Fields: Completed Under the Energy Policy Act of 1992 PI Topic Exposure Result Funded (FY) Replication Reiter Univ. of Texas Health Science Center MF effects on pineal melatonin in rats 0.025, 0.05, and 0.1 mT continuously and intermittently for 12 h No statistically significant effects on pineal melatonin in 17 experiments conducted with Yellon or Selmaoui and Touitou acute exposure protocols 1994 Attempt to verify MF effects on melatonin as mechanism of MF health effects with multiple acute MF-exposure protocols Yost Univ. of Washington MF effects on melatonin in utility workers Environmental fields of 0.1–0.3 [.muT measured with personal exposure meters for reanalysis of data of Butch and colleagues (1998) Trend of decreased nocturnal melatonin after increased MF exposure during workday; weaker correlation when compared with h mean exposures, suggesting a confounder; results have borderline statistical significance 1997 Reanalysis of data from study by Burch and co-workers reporting an association between MF exposures of utility workers and lowered melatonin (Butch and others 1998)
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Research on Power-Frequency Fields: Completed Under the Energy Policy Act of 1992 Biology Summary The first three categories of biology projects are of limited use for the evaluation of health effects at the present time. The majority of the information was provided to the committee in the form of 2–3 page project summaries. It was not always clear whether the work was hypothesis driven or "screening for effect" investigations. If published in peer-reviewed journals the hypothesis-driven studies could have value even if they report negative results. Category 4 projects provided sufficient information, either in the project summaries, or in solicited material sent to the committee, to estimate the magnitude of the reported effect. The reports of effect in this category are unconfirmed. Category 5, the replication category, is an important classification in the committee's judgement. This final category includes a wide scope of replication studies, ranging from "exact replications" to attempts to replicate general effects (transformation for example). The results of these replication studies are almost entirely negative. Discussion From a technical perspective, the EMF-RAPID program has helped incrementally to answer the basic question of whether environmentally relevant power-frequency MFs can produce biologic effects. The engineering studies underscore the fact that time-averaged MF exposures in a wide range of occupations are remarkably similar. That has implications for the interpretation and design of epidemiologic investigations. The literature on laboratory studies of this subject is full of conflicting claims. The only responsible way to deal with the situation is to subject the most important positive reports to multiple independent replication. EMF-RAPID made a substantial start on replication, which is an important contribution. The replications conducted under the program have had almost entirely negative results and thus have reduced the credibility of many of the claims of biologic effects of power-frequency MFs. If it can be shown unequivocally that low-level power-frequency MFs do produce biologic effects, and if the effects are robust enough for the scientific community to reproduce the phenomena routinely, the underlying biophysical mechanism will eventually be established. However, the EMF-RAPID program has shown that much of the literature on MF bioeffects is questionable, in that it is not easily replicated. No finding from the EMF-RAPID program substantially contradicts the conclusions of the earlier National Research Council committee report Possible Health Effects of Exposure to Residential Electric and Magnetic Fields (NRC 1997). Information-Dissemination Projects The Energy Policy Act of 1992 specified that the EMF-RAPID program should "provide for dissemination of information . . . to the public". Two of the four objectives of the National Electric and Magnetic Field Research and Communication Program: Draft Strategic Plans5 were not met: 5 For communication objectives see page 16 of this report
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Research on Power-Frequency Fields: Completed Under the Energy Policy Act of 1992 "Plan, support, and conduct communication research." The committee is unaware of any communication research funded under EMF-RAPID. "Encourage communication from public decision-makers to those who plan scientific studies". The committee found little evidence of such encouragement, although it is not clear what was intended by the objective, and the interagency committee might be seen as fulfilling this aim. Information-Dissemination Booklets Two booklets were published as part of the EMF-RAPID communication effort. The first, Questions and Answers About EMF: Electric and Magnetic Fields Associated With the Use of Electric Power (DOE 1995) was reviewed in the committee's interim report. The present EPACT Committee concurs with the original assessment on page 20 of this report. According to information provided by NIEHS, about 180,000 copies of the booklet have been dispersed, half going to utilities for distribution to customers and the remainder going to state and local governments and to fill requests from the public. An additional 20,000 copies of the booklet were printed in Spanish; about 16,000 copies have been dispersed. The committee, in its interim report, concluded that more booklets of this sort should be published and suggested that it would be useful to prepare a more comprehensive guide, which would include biologic effects observed in the laboratory and an extended reference section for the more technically interested reader. A second booklet, Questions and Answers EMF in the Workplace, was produced by EMF-RAPID. This booklet included some of the same information as the first booklet, but it also included chapters on human health studies (epidemiology) and biologic research (animal and cell biology). Information was presented on MF measurements, and examples of MF exposure in the workplace were included. It identifies other information sources and includes an extended reference section. The booklet was printed in the United States and Canada, and NIEHS has estimated that 65,000 copies were distributed in the United States. It meets the recommendations of the interim EPACT Committee report. EMF InfoLine The Environmental Protection Agency (EPA) initially operated a toll-free telephone EMF-information line jointly funded by EPA and EMF-RAPID. In 1998, oversight of the line was assumed by NIEHS. The information line responds to public inquires about both 60-Hz MFs and radio-frequency radiation, and it refers callers to appropriate resources. The persons who answer calls also take orders for the two booklets described above. Calls to the line seem to be handled responsibly. The EPACT Committee has no information on funding support for this seemingly useful activity. EMF-RAPID Web Site The NIEHS EMF-RAPID Web site (http://www.niehs.nih.gov/emfrapid/home.htm) contains a number of documents available to any member of the public who has access to the Internet. The number of requests for downloads averages 161 per day. For the period
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Research on Power-Frequency Fields: Completed Under the Energy Policy Act of 1992 March 1, 1997, to June 30, 1998, a total of 78,128 files were downloaded from the site. Items are added and occasionally removed from the site, but a menu existing in August 1998 illustrates the type of information that is available: Overview and program focus: a one-page description of the program. Program organization, staff, and components. EMF annual reports: NIEHS reports for years 1994–1996 with updates for 1996 and 1997. EMF-RAPID interim report to congress, December 1995. Research information: short (two or three page) project summaries of the 61 projects funded by EMF-RAPID and some projects funded by other means. Some of the project summaries included on the Web site have many of the same shortcomings as those in the project summary books provided to the committee. Data sometimes were incomplete, absent, or not current. Occasionally, cited figures and tables are not present. It sometimes appears that publications cited as resulting from projects predate the projects or are not related to them. Some funding information and contact information on the principal investigators are provided. EMF regional magnetic field exposure facilities: brief descriptions of the four facilities designed to provide uniform MF exposures for the EMF-RAPID program, links to the four institutions (Food and Drug Administration, National Institute for Occupational Safety and Health, Oak Ridge National Laboratory, and Pacific Northwest National Laboratory), and an e-mail contact for each program. EMF-science review symposia and meetings: information from the three NIEHS symposia and the Department of Energy engineering symposium. The discussion of the DOE engineering component was fragmentary and incomplete at the time this report was written. Questions and Answers about EMF: this booklet can be accessed directly or downloaded from the Web site. EMF in the Workplace-Questions and Answers: can be accessed directly or downloaded from the site. EMF measurements database: ''The purpose of this project is to make measurements of EFs and MFs publicly available". A small amount of information from the engineering symposium is available here. Three data sets had been entered at the time of committee review. The database is not judged to be user-friendly. Other MF information sources: directs the users to other sources MF information. Working-group report: available in PDF and HTML versions. Miscellaneous An EMF "sourcebook" was created in a hard copy version and on the Internet. The hard copy version of the sourcebook consists of materials similar to those appearing on the EMF-RAPID Web site (described previously). Two travel grants were awarded to allow representatives from citizen groups concerned about EMFs to attend the 1995 annual DOE contractors' meeting in Palm Springs, CA.
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Research on Power-Frequency Fields: Completed Under the Energy Policy Act of 1992 Summary Regarding a third objective of the draft strategic plan—"improve coordination and communication with the national and international scientific community. Provide referral services . . ."—the scientific symposia (discussed in the next section of this report) did meet the objective of improving communication among the scientific community. The committee finds the scientific and technical quality of the information to be acceptable. The objective to "provide referral services" is partially met by the Web site described above, and referral services were also provided by the EMF-RAPID information line. If data were regularly entered into the database, progress toward meeting this objective would be improved. Finally, the fourth objective of educating the public and others is addressed by many of the activities listed above. However, much of the material is in a format or a language directed at the technical community. The first booklet was written for the general public. The committee recommends that NIEHS work to make the Web site easily accessible for the general public. EMF Science-Review Symposia NIEHS organized three EMF science-review symposia that were intended to review the literature on several major power frequency magnetic field research subjects. The first covered theoretical mechanisms and in vitro research, the second covered epidemiologic research, and the third covered clinical and in vivo laboratory research. The meetings were open to the public. The "breakout group" reports of the meetings are available as NIEHS publications (NIEHS 1997; NIEHS 1998b,c) and also are available to the public on the EMF-RAPID Web site. The reports reasonably summarize the meetings. However, despite the hard work of many participants, the meetings did not constitute a systematic, comprehensive review of the literature. The most important accomplishment of the three biology-review symposia might have been to educate newcomers brought into the risk-assessment process being considered by NIEHS. For example, discussion groups attempted to answer specific questions posed by NIEHS. Some of these questions were related to summaries of the state of the science, and other questions were related to hazard identification and risk assessment. However, on-site ad hoc efforts to review a selected subset of extensive and complex scientific literature in a few hours in a large public meeting did not provide an effective and satisfying product. Thus, the scientific value of these meetings is less than that of the 1997 National Research Council committee report (NRC 1997), the 1998 NIEHS working-group report (NIEHS 1998a), or other published reviews. Furthermore, with respect to communication among members of the bioelectromagnetics community, the three NIEHS biology review meetings were supplementary efforts added to the two prime scientific meetings, the DOE contractors' conference and the Bioelectromagnetics Society meeting, which have been held annually for at least 2 decades. The NIEHS working group did not use the three EMF science-review symposium booklets in a formal way. It is not known whether they will be used by NIEHS in the preparation of its final report.
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Research on Power-Frequency Fields: Completed Under the Energy Policy Act of 1992 A fourth symposium on the engineering component of the EMF-RAPID program, sponsored by DOE, allowed principal investigators who had completed detailed engineering-project reports to present their methods and findings publicly, and discuss them with interested participants (NIEHS 1998d). EMF-RAPID Working-Group Report The working-group meeting, held June 16–24, 1998, in Brooklyn Park, MN, produced an NIEHS report titled Assessment of Health Effects from Exposure to Power-Line Frequency Electric and Magnetic Fields (NIEHS 1998a). A press release described the essential findings of the report, and the report was made available for public review (hard copy and CD-ROM available by mail) and placed on the EMF-RAPID Web site in several formats. A period for public review and comment was designated from August 10, 1998, through October 9, 1998. The public was encouraged to comment on the report by mail or in person at three locations: Washington, DC, on September 28, 1998; San Francisco, CA on October 1, 1998; and Chicago, IL, on October 5, 1998. A fourth opportunity for public comment occurred on the afternoons of September 14 and 15, 1998, at the annual EMF contractors' meeting sponsored by DOE in Tucson, AZ. Records of the public comments are available to the public at various sites in the United States. Under the EMF-RAPID program, NIEHS established the working group to assess health effects of exposure to power-frequency magnetic fields. The working group, consisting of 29 voting members, met on June 16–24, 1998, in Brooklyn Park, MN. Twelve of the participants contributed to first-draft documents before the meeting. As in the three biology symposia, the working group largely considered published findings. Papers and reports that had not been published but that provided enough detail, including results of in vivo studies funded by RAPID, were considered. Although this rule was not always strictly adhered to, it tended to eliminate current EMF-RAPID research from consideration or discussion. The NIEHS working group reviewed essentially the same epidemiology that was reviewed by the Research Council committee on Possible Health Effects of Exposure to Residential Electric and Magnetic Fields (NRC 1997), adding the literature accumulated from 1996 to 1998. The two reviews differed in a number of important ways. Perhaps the most important were the time available for arriving at the conclusions and the process of arriving at the wording of the conclusions. The Research Council committee functioned for several years and had intensive discussions over the course of many meetings. The NIEHS working group as a whole was operational for 10 d, and most of the time was devoted to arriving at the final language of the literature review. The discussions in which conclusions were reached occurred at the end of the meeting and were very limited in time. The Research Council committee developed its conclusions, after multiple discussions among the whole committee, in the form of a consensus report agreed to by all participants. The NIEHS working group was directed to follow the process used by IARC. The participants answer a set of predefined questions in successive votes. The questions cannot be modified during the process, and the weight of the participants' opinions is equal for all questions and votes, regardless of their disciplines and expertise. No effort was made to reach consensus nor to identify and explain differences in opinion.
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Research on Power-Frequency Fields: Completed Under the Energy Policy Act of 1992 Much of the working group's time was spent in small groups as subcommittees worked to write specific sections of the literature review. Although plenary sessions were held, these usually were attended only by groups that wrote the text or by individuals from closely related fields of expertise. The process used by the Research Council committee involved long and repeated discussions in which the expertise of the participants could be considered in arriving at a consensus. The findings and conclusions were framed in ways that allowed a consensus to be developed. Furthermore, they reflected nuances based on the context of the weight of evidence that was discussed in many sessions in which all members took part. This negotiated consensus was a set of conclusions arrived at by all the participants after multiple sessions of open discussion. The process put a premium on the persuasiveness of the evidence and on the ability of participants of one discipline to persuade participants from other disciplines about the value of different lines of evidence. The value of the IARC-based process is its following of an established process used extensively in the evaluation of the carcinogenicity of hundreds of compounds. The IARC process leads to a definite result—the evaluation of the human carcinogenicity of an agent. Because an agent to be evaluated with the IARC process needs to be a suspect carcinogen and because the process is conservative in the prescribed steps, it is not surprising that IARC evaluations are extremely likely to result in a finding of possible carcinogenicity. The IARC process is guided by the epidemiologic evidence in humans which can be "sufficient", "limited" or "inadequate". Animal evidence can be "sufficient", ''less than sufficient", "limited", and "inadequate". The final characterization of the exposure can then be Group 1 "carcinogenic" (human:sufficient, animal:sufficient), Group 2A "probably carcinogenic" (human:limited, animal:sufficient), Group 2B "possibly carcinogenic" (human:limited, animal:less than sufficient), Group 3 "not classifiable" (human:inadequate, animal:inadequate or less than sufficient), and Group 4 "probably not carcinogenic" (human:evidence suggesting lack of carcinogenicity, animal:evidence suggesting lack of carcinogenicity) or (human:inadequate, animal:lack of carcinogenicity). The process does not recognize lack of carcinogenicity in animals except in Group 4, and that would require a finding that the human evidence was inadequate. Both reviews (NRC 1997; NIEHS 1998a) had the benefit of meta-analysis of epidemiologic findings, and much the same approach was used in both meta-analyses. The meta-analyses were carried out on the basis of published data; considerable differences existed in the design and execution of the studies. Characterization of the exposure to EMFs varies widely in different studies, and it is not possible at this time to identify the most relevant metric for characterizing exposure. The appropriateness of converting wire codes into assigned levels of MFs on the basis of the few simultaneous observations of wire codes and direct measurements in homes may be a questionable undertaking but it is necessary to link different studies. Many of the meta-analyses were based on categorical estimates of exposure; few analyses addressed exposure estimates of a continuous nature. The meta-analyses in both reports contain numerous cautions as to many inherent weaknesses, but they then proceed to present the combined results of a large number of analyses. One purpose of the meta-analyses is to see whether the combined statistical power of several studies provides more significant associations. The
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Research on Power-Frequency Fields: Completed Under the Energy Policy Act of 1992 meta-analyses have not increased the strength of the association, although one does get the expected increase in statistical significance. The Research Council committee report and the NIEHS working-group report reviewed much of the same epidemiology. The latter group had the ability to review literature published in 1996–1998, although no definitive or extraordinary epidemiologic studies were published during the 2-yr period. The conclusions are not greatly dissimilar, but the two processes resulted in differently worded statements. The Research Council committee report (NRC 1997) concluded that; Living in homes classified as being high in the wire-code category is associated with about a 1.5-fold excess of childhood leukemia, a rare disease. MFs measured in the home after diagnosis of disease in a residence have not been found to be associated with an overall excess incidence of childhood leukemia or other cancers. Studies have not identified the factors that explain the association between wire codes and childhood leukemia. Taken together, epidemiologic evidence does not support possible associations of MFs with adult cancers, pregnancy outcome, neurobehavioral disorders, and childhood cancers other than leukemia. MF exposures at 50–60 Hz delivered at field strengths similar to those measured in typical residential exposures (0.01–1.0 µT) do not produce any significant in vitro effects that have been replicated in independent studies. Reproducible changes have been observed in the expression of specific features in the cellular signal-transduction pathways for MF exposures at about 100 µT and higher. There is no convincing evidence that exposure to 60-Hz power-frequency magnetic fields causes cancer in animals. There is no evidence of any adverse effects on reproduction or development in animals, particularly mammals, from exposure to power-frequency 50- or 60-Hz EFs and MFs. There is convincing evidence that low-frequency pulsed MFs greater than 0.5 mT are associated with bone-healing responses in animals. A number of additional conclusions and recommendations in the Research Council committee report referred to findings and recommendations about research needs. The final summary and evaluations of the NIEHS working-group report (NIEHS 1998a), offer the following statements: The working group concluded that ELF MFs are "possibly carcinogenic" in humans (supported by 19 members; eight members considered the evidence as not allowing a classification as to carcinogenicity, one member considered the evidence as indicating noncarcinogenicity in humans, and one member abstained from voting). Of 26 working-group members voting on the question, 20 concluded that there was limited evidence that residential exposure to ELF MFs is carcinogenic in children on the basis of the results of epidemiologic studies of childhood leukemia; the remaining six voting members concluded that there was inadequate evidence.
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Research on Power-Frequency Fields: Completed Under the Energy Policy Act of 1992 Of 25 working-group members voting on the question, 14 concluded that there was limited evidence that occupational exposure to ELF MFs is carcinogenic in humans, primarily on the basis of results of studies of chronic lymphocytic leukemia; the remaining 11 voting members concluded that there was inadequate evidence. Of 25 working-group members voting on the question, 22 concluded that there was inadequate evidence of an association between occupational exposure to ELF MFs and the risk of cancers other than leukemia; two members concluded there was limited evidence, and one that there evidence for lack of an effect. Of 25 working-group members voting on the question, 24 concluded that there was inadequate evidence that residential exposure to ELF MFs is carcinogenic in adults; the other member concluded there is evidence for lack of an effect. All 25 working-group members voting on the question concluded that there was inadequate evidence of an association between exposure to ELF MFs and childhood nervous system tumors or childhood lymphoma. Of 27 working-group members voting on the question, 19 concluded that there was inadequate evidence in experimental animals of the carcinogenicity of exposure to ELF MFs; the remaining eight members concluded that there was evidence of lack of an effect. It is worth noting that no working-group member voted for the conclusion that ELF MFs are "carcinogenic" or "probably carcinogenic". It is unfortunate that the summary statements focused so heavily on cancer. The extensive literature reviewed in the report addressed effects other than cancer. When the working-group report is considered in more detail, the dramatic contrast apparent between the Research Council committee report (NRC 1997) and the NIEHS report (NIEHS 1998a)—"no effect" versus "possible carcinogen"—is reduced; and when the differences between the two evaluation processes that were used are taken into account, the difference in conclusions is understandable. The current committee concludes, however, that the conclusions of the 1997 Research Council committee report (NRC 1997) more accurately convey the health implications of the underlying research to the public. Several national and international organizations are involved in developing exposure guidelines for EFs and MFs, and several such guidelines have been published for power frequencies. The predecessor of the International Commission for Non-ionizing Radiation Protection (ICNIRP) and the International Non-ionizing Radiation Committee (INIRC) of the International Radiation Protection Association (IRPA), published exposure guidelines for power-frequency EFs and MFs in 1990 (ICNIRP 1990; IRPA/INIRC 1990). These guidelines were recently updated by ICNIRP (ICNIRP 1998) and extended to include exposure to power-frequency magnetic fields with frequencies up to 300 GHz. Similar guidelines or standards have been developed by the American Conference of Governmental Industrial Hygienists (ACGIH 1998) and by the Institute of Electrical and Electronic Engineers (IEEE 1997). These guidelines are based on known acute effects of EFs and MFs. Although all those organizations are aware of the epidemiologic literature dealing with reported associations between EMF exposure and different cancer end points, the data from such experiments have not affected the recommended exposure guidelines. The reasons are the lack of quantitative data about
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Research on Power-Frequency Fields: Completed Under the Energy Policy Act of 1992 these associations, the lack of consistency in the reported outcomes, and the lack of adequate characterization of the exposures. It is not possible to determine how much protection can be obtained against undefined risks that might or might not exist at relevant exposures. In the absence of clear, reproducible effects at relevant EMF exposures, the tendency is often to limit exposures specific to the situation or to prescribe that exposures at new installations be held below levels experienced in existing installations. Discussion and Recommendations The results of the EMF-RAPID program do not support the contention that the use of electricity poses a major unrecognized public-health danger. Basic research on the effects of power-frequency magnetic fields on cells and animals should continue, but a special research funding effort is not required. Investigators should compete for funding through traditional research-funding mechanisms. If future research on this subject is funded through such mechanisms, it should be limited to tests of well-defined mechanistic hypotheses or replications of reported positive effects. If carefully performed, such experiments will have value even if their results are negative. Special efforts should be made to communicate the conclusions of this effort to the general public effectively. The following specific recommendations are made by the committee: The committee recommends that no further special research program focused on possible health effects of power-frequency magnetic fields be funded. Basic research on the effects of power-frequency magnetic fields on cells and animals should continue but investigators should compete for funding through traditional research-funding mechanisms. If, however, Congress determines that another time-limited, focused research program on the health effects of power-frequency magnetic fields is warranted, the committee recommends that emphasis be placed on replications of studies that have yielded scientifically promising claims of effects and that have been reported in peer-reviewed journals. Such a program would benefit from the use of a contract-funding mechanism with a requirement for complete reports and/or peer-reviewed publications at program's end. The engineering studies were initiated without the guidance of a clearly established biologic effect. The committee recommends that no further engineering studies be funded unless a biologic effect that can be used to plan the engineering studies has been determined. Much of the information from the EMF-RAPID biology program has not been published in peer-reviewed journals. NIEHS should collect all future peer-reviewed information resulting from the EMF-RAPID biology projects and publish a summary report of such information periodically on the NIEHS Web site.
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Research on Power-Frequency Fields: Completed Under the Energy Policy Act of 1992 The communication effort initiated by EMF-RAPID is reasonable. The two booklets and the telephone information line are useful, as is the EMF-RAPID Internet site. There are two limitations to the effort. First, it is largely passive, responding to inquiries and providing information, rather than being active. Second, much of the information produced is in a scientific format not readily understandable by the public. The committee recommends that further material produced to disseminate information on power-frequency magnetic fields be written for the general public in a clear fashion. The Web site should be made more user-friendly. The booklet Questions and Answers about EMF should be updated periodically and made available to the public.
Representative terms from entire chapter: