An important requisite for the credibility of epidemiologic findings of weak associations between surrogate estimates of MF exposure and excess cancer risk is assessment of the evidence that supports the biologic plausibility of such an association. Results of the laboratory experiments that have sought to link MF exposure and processes associated with any biologic precursors to carcinogenesis strongly suggest that ELF MFs do not cause cancer promotion and do not affect progression (NRC 1997; NIEHS 1998a). Some laboratory studies have reported evidence of biologic response after exposure to MFs, but they have not been independently confirmed in the peer-reviewed literature. Most of the unconfirmed biologic effects have not been conclusively associated with detrimental health effects. Although the history of study of the responses of biologic systems to exposure to power-frequency magnetic fields is extensive, no conclusive evidence of the potential for such fields to cause detrimental health effects has been produced, other than effects caused by direct contact with electrical conductors.

Public alarm about the possibility of adverse health consequences of exposure to MFs associated with electric-power transmission, distribution, and use is increased by scientific uncertainty. The tragedy of cancer often provokes in a family, or a patient, a strong need to understand the cause. Many cancer patients and their families worry about the possibility that the disease might arise from previous exposures to power-frequency magnetic fields. Accounts in the mass media offer examples of "clusters" in which a small group of people exhibits an apparently high frequency of cancer. It then is a simple step for the public to draw an association between MF exposure and cancer, even though such clusters are sometimes expected as statistical artifacts. When serious uncertainties in interpretation of available evidence arise in a subject in which one or another interpretation would have serious technical and economic consequences, it is important for the government to help to resolve the issues.

As noted, there has been extensive study of the response of biologic systems to exposure to MFs, but there is still no conclusive scientific evidence that such fields cause detrimental health effects. Literature reviews have been undertaken by the Oak Ridge Associated Universities (ORAU 1992), working under the sponsorship of the Committee on Interagency Radiation Research and Policy Coordination; by the Environmental Protection Agency (EPA 1990); by the National Radiological Protection Board of the United Kingdom (NRPB 1992, 1994); by the government of Australia (Peach and others 1992); by the National Research Council (NRC 1997); and by NIEHS (NIEHS 1998a). With one exception, these reviews have come to the same general conclusion: there is little or no evidence that ELF-MF exposure leads to an increased incidence of cancer. The exception is the previously noted NIEHS working-group report (NIEHS 1998a) which, using strictly defined International Agency for Research on Cancer (IARC) guidelines, placed ELF MFs in the "possibly carcinogenic" classification.

EMF-RAPID PROGRAM RESEARCH STRATEGY

In 1993, the Department of Energy (DOE) published a document that recommended activities that should be considered for the following 5 yr in four related program subjects: scientific research, engineering research, communication, and policy support. The document (DOE 1993), entitled The National Electric and Magnetic Fields Research and Communication Program: Draft Strategic Plan, is the national EMF research plan referred to in the charge to the present EPACT Committee. The plan outlined specific



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OCR for page 14
Research on Power-Frequency Fields: Completed Under the Energy Policy Act of 1992 An important requisite for the credibility of epidemiologic findings of weak associations between surrogate estimates of MF exposure and excess cancer risk is assessment of the evidence that supports the biologic plausibility of such an association. Results of the laboratory experiments that have sought to link MF exposure and processes associated with any biologic precursors to carcinogenesis strongly suggest that ELF MFs do not cause cancer promotion and do not affect progression (NRC 1997; NIEHS 1998a). Some laboratory studies have reported evidence of biologic response after exposure to MFs, but they have not been independently confirmed in the peer-reviewed literature. Most of the unconfirmed biologic effects have not been conclusively associated with detrimental health effects. Although the history of study of the responses of biologic systems to exposure to power-frequency magnetic fields is extensive, no conclusive evidence of the potential for such fields to cause detrimental health effects has been produced, other than effects caused by direct contact with electrical conductors. Public alarm about the possibility of adverse health consequences of exposure to MFs associated with electric-power transmission, distribution, and use is increased by scientific uncertainty. The tragedy of cancer often provokes in a family, or a patient, a strong need to understand the cause. Many cancer patients and their families worry about the possibility that the disease might arise from previous exposures to power-frequency magnetic fields. Accounts in the mass media offer examples of "clusters" in which a small group of people exhibits an apparently high frequency of cancer. It then is a simple step for the public to draw an association between MF exposure and cancer, even though such clusters are sometimes expected as statistical artifacts. When serious uncertainties in interpretation of available evidence arise in a subject in which one or another interpretation would have serious technical and economic consequences, it is important for the government to help to resolve the issues. As noted, there has been extensive study of the response of biologic systems to exposure to MFs, but there is still no conclusive scientific evidence that such fields cause detrimental health effects. Literature reviews have been undertaken by the Oak Ridge Associated Universities (ORAU 1992), working under the sponsorship of the Committee on Interagency Radiation Research and Policy Coordination; by the Environmental Protection Agency (EPA 1990); by the National Radiological Protection Board of the United Kingdom (NRPB 1992, 1994); by the government of Australia (Peach and others 1992); by the National Research Council (NRC 1997); and by NIEHS (NIEHS 1998a). With one exception, these reviews have come to the same general conclusion: there is little or no evidence that ELF-MF exposure leads to an increased incidence of cancer. The exception is the previously noted NIEHS working-group report (NIEHS 1998a) which, using strictly defined International Agency for Research on Cancer (IARC) guidelines, placed ELF MFs in the "possibly carcinogenic" classification. EMF-RAPID PROGRAM RESEARCH STRATEGY In 1993, the Department of Energy (DOE) published a document that recommended activities that should be considered for the following 5 yr in four related program subjects: scientific research, engineering research, communication, and policy support. The document (DOE 1993), entitled The National Electric and Magnetic Fields Research and Communication Program: Draft Strategic Plan, is the national EMF research plan referred to in the charge to the present EPACT Committee. The plan outlined specific

OCR for page 14
Research on Power-Frequency Fields: Completed Under the Energy Policy Act of 1992 goals and objectives for the four major program components: The EMF scientific-research component would seek to determine whether human health effects result from exposure to power-frequency magnetic fields; research activities were to include epidemiologic, cellular, molecular, and large-scale animal studies. The EMF engineering-research component was to characterize the MF exposure of various residential and worker groups and to develop a range of options for managing MF exposure. EMF communication activities were to improve understanding of MF issues by seeking input from concerned citizens and other interested groups, by improving discussion between communities and agencies, by investigating means to improve the communication process, and by providing the public with balanced and credible information on which to base public-policy decisions and individual judgments. EMF policy support was to include "research and analysis to understand the societal, ethical, economic, and legal implications of the MF issue and provide government and business decision makers with a wide range of policy options". Specific objectives were identified for each of the four components; these are paraphrased below from the National Electric and Magnetic Fields Research and Communication Program: Draft Strategic Plan (DOE 1993). The stated objectives of the scientific research component were to: determine the biologic effects of electric and magnetic fields on humans, animals, tissues, and cells; conduct replication studies designed to duplicate previous research methods in an attempt to resolve conflicting research results and confirm key research findings; determine the underlying causes of any biologic effects; establish quantitative dose-response or other quantitative relationships between exposure and effect; and determine whether an association exists between EMF exposure and human health effects using well-designed epidemiologic studies. Objectives of the EMF Engineering Research Program Component were: development and evaluation of instrumentation and techniques for measuring various types of electric and magnetic fields and assessing personal exposure; assessment of exposure of various residential and worker groups in terms of the various types of electric and magnetic fields; development and evaluation of the costs, benefits, and effectiveness of options for managing EMF exposures from a variety of sources; development of equations and methods (computer simulations) for estimating electric and magnetic field strengths and power-frequency magnetic field exposures in situations where direct measurements are not feasible; development of standardized procedures for EMF exposure measurements to facilitate comparisons between research findings; and development of equations and methods (computer simulations) that relate external (outside the body) measurements of EMF exposures to internal (inside the body) power-frequency magnetic field doses experienced by the biologic system.