Health Sciences Practice. Health Evaluation of Exposure to Radiofrequency Energy from AM Radio Antennas

Transcription

1 Health Sciences Practice Health Evaluation of Exposure to Radiofrequency Energy from AM Radio Antennas

2 Health Evaluation of Exposure to Radiofrequency Energy from AM Radio Antennas Prepared for BBC Broadcasting, Inc. KRPI Conditional Use Permit Application SEP &CUP Whatcom County Prepared by Exponent 420 Lexington Avenue Suite 1740 New York, NY March 31, 2014 Exponent

3 Contents Page Limitations Executive Summary ii iii I. Introduction 1 II. Scientific Review Process 2 Procedures for evaluating epidemiologic research 4 III. Scientific Reviews of Radiofrequency Fields and Health 9 IV. Evaluation of Materials Submitted and Recent Epidemiology Research 13 Epidemiology research on RF energy from radio transmitters focusing on a single study can be misleading 14 IARC review of RF energy 20 V. Questions Posed by the Whatcom County Staff 22 VI. References 24 Appendix A List of Evaluated Documents Submitted in Public Comments i

4 Limitations At the request of BBC Broadcasting, Inc., Exponent prepared this Health Evaluation of Exposure to Radiofrequency Energy from AM Radio Antennas. The findings presented herein are made to a reasonable degree of scientific certainty. Exponent reserves the right to supplement this report and to expand or modify opinions based on review of additional material as it becomes available, through any additional work, or review of additional work performed by others. This investigation was conducted for BBC Broadcasting, Inc., and any re-use of this report or its findings, conclusions, or recommendations presented herein are at the sole risk of the user. The opinions and comments formulated during this assessment are based on observations and information available at the time of the investigation. No guarantee or warranty as to future life or performance of any reviewed condition is expressed or implied ii

5 Executive Summary Exponent has been asked to assess the potential for adverse health effects from exposure to the radiofrequency (RF) energy that will be emitted by the proposed KRPI-AM radio station 1 in Point Roberts, Washington, and to consider material submitted with public comments on RF and health. The Whatcom County staff has asked Are there any associated health risks regarding RF radiation exposure? and What studies, if any are available to show there are no inherent risks. This report addresses each of these questions, as well as evaluating and responding to comments submitted by the public. This report first explains how scientists in health and regulatory agencies critically evaluate the relevant scientific research studies to assess the health risks from exposure to RF energy. This is a standard process used to assess any environmental exposure. A scientific assessment of health risks associated with RF energy is a complex process, which involves evaluating the relevant research (i.e., epidemiology and laboratory studies), and giving more weight to those studies of the highest quality because better research provides more reliable information. The methods used in a scientific assessment are described in Section II, and the conclusions of these evaluations are summarized Section III, which includes the website locations where the public can access them. To take just one example, the Swedish Radiation Safety Authority concluded, regarding the low level RF exposure from base stations and radio antennas, that Available data do not indicate any risks related to exposure to RF from base stations or radio or TV antennas. Taking into account also the low levels of exposure that these sources give rise to, health effects from transmitters are unlikely (SSM, 2010). A major result of these assessments has been to develop exposure limits, or standards, to ensure that neither workers nor members of the public are exposed to the very high levels associated with potential impacts on human health. Scientists have found that RF levels in compliance with exposure limits set by the Federal Communications Commission (FCC) do not 1 The proposed radio transmitter facility will broadcast AM signals at a frequency of 1,550 kilohertz with a power of 50 kilowatts during both daytime and nighttime (FCC AM Broadcast Construction Permit) iii

6 pose a risk to human health. This conclusion is based on the most reliable laboratory and epidemiology studies, including studies of laboratory animals exposed to fields of high RF intensity over the animals life span, as well as epidemiology studies of humans exposed to RF energy from AM radio antennas (a relatively low exposure) and RF energy from mobile phones (a relatively higher exposure). The scientific reviews summarized in Section III include the answer to the second question posed by the Whatcom County staff because conclusions reached by these organizations include a weight-of-evidence evaluation from numerous studies. To support the Whatcom County staff s inquiry, as well as respond to public comments, Section IV summarizes recent research studies of sources from broadcast transmitters and cancer that have been designed to improve upon earlier studies, which examined cancer in geographic areas surrounding antennas. The recent studies include larger numbers of individuals, as well as improved measurements of RF exposure of individuals from AM radio sources, two factors that provide more reliable estimates of possible risk. The more extensive studies did not find evidence of increased cancer in children exposed to RF fields from broadcast facilities, that is, the risk estimate for people who resided in exposed areas could not be distinguished from those who resided in locations that were not exposed. These studies of exposure of RF fields from broadcast transmitters, along with the weight-ofevidence reviews cited in Section III, show that there is no inherent public health risk associated with the operation of RF sources like the KRPI transmitter. 2 These reviews have led to conclusions that the exposure limits based on scientific research, such as the limits set by FCC and used in the United States, and the limits established by the International Commission on Non-Ionizing Radiation Protection (ICNIRP) and are recommended by the World Health Organization, fully protect the members of the general public from adverse effects. These reviews have evaluated the research about hypothesized health effects, including those purported to occur from long-term exposures at low levels, and have not concluded that they support lowering the FCC or ICNIRP standards. 2 If exposure to RF fields at the antenna exceeded the occupational exposure limit by a large margin it could pose a known hazard from tissue heating (FCC, 1999) iv

7 Thus, to assess whether exposure from a given facility is without risk to the public, it is essential to compare the RF field intensity created by the AM radio transmitter with the FCC exposure limits the relevant standard in the United States v

8 I. Introduction Exponent has been asked to assess the potential for adverse health effects from exposure to the radiofrequency (RF) energy that will be emitted by the proposed KRPI-AM radio station 3 in Point Roberts, Washington, and to consider materials submitted with public comments on RF and health. An assessment of possible adverse effects on health must be based on a critical and systematic evaluation of scientific research (i.e., a weight-of-evidence review); therefore, this report first describes the process scientists use worldwide to assess possible effects of specific environmental exposures, such as RF energy, and a specific discussion of the review process for epidemiologic research (Section II). Section II also explains why these methods are essential for reaching valid conclusions. Section III summarizes the conclusions of weight-of-evidence reviews on RF that were conducted by scientific and health organizations using the methods discussed in Section II, and provides information on where both these reviews and summaries of their research are available. Section IV includes an evaluation of the materials submitted with public comments in this proceeding. In this section we also assess epidemiology studies that have examined associations between population exposure to RF fields from amplitude-modulated (AM) radio transmitters and human health (including one of the research studies submitted by the public), as an example of the process explained in Section II. Section V directly addresses two questions asked by the Whatcom County staff regarding the KRPI-AM proposal: Are there any associated health risks regarding RF radiation exposure? and What studies, if any, are available to show there are no inherent risks? The proposed radio transmitter facility will broadcast AM signals at a frequency of 1,550 kilohertz with a power of 50 kilowatts during both daytime and nighttime (FCC AM Broadcast Construction Permit). Whatcom County letter to AUT Consulting, Inc., dated November 6,

9 II. Scientific Review Process The potential health risks of environmental exposures to RF energy have been the subject of numerous scientific research studies. The relevant research studies are those published in peerreviewed scientific literature from several research areas: human epidemiology studies; experimental laboratory studies in animals (in vivo); and experimental laboratory studies in cells and tissues (in vitro). The numerous studies from these different lines of research are typically considered together to make decisions about the way in which exposures could affect human health, and if so, at what level of exposure. The process of evaluating this research is called a weight-of-evidence review. This involves a systematic identification of the relevant studies on the exposure of interest published in peer-reviewed scientific literature from these research areas. This section describes the standard weight-of-evidence review process that health and scientific organizations undertake to address health questions, followed by more specific information for evaluating epidemiology studies in a weight-of-evidence assessment. Since every research study has strengths and limitations, no single study in itself, without considering the rest of scientific research, is sufficient to answer the question of causation (i.e., does the exposure produce health effects?). It is incumbent upon health and scientific organizations that conduct reviews to evaluate the full body of research, regardless of whether a study s results indicate that an effect was observed (a positive study ) or whether a study s results indicate no effect (a negative study). Scientific and health agencies assemble panels of scientists in the relevant areas of expertise to conduct such weight-of-evidence reviews. As mentioned, a weight-of-evidence review begins with a systematic identification and review of published, peer-reviewed epidemiology and experimental research. The weight that individual studies contribute to the overall conclusions is not equal studies vary widely in terms of the validity of their methods and success in implementation. Therefore, each study from each discipline must be evaluated critically. An overall conclusion about the effect of a particular type of exposure is then reached by considering the cumulative body of research, giving more weight to studies of higher quality and validity. 2

10 These principles are important because no single study is perfect or determinative, and because each research area has inherent strengths and limitations. Epidemiology studies examine the occurrence of disease in humans; they have a high value because they examine the species of interest. Studies that demonstrate increased risk with higher dose (as estimated by the exposure level) are indications of a dose-response pattern, which, if consistent across valid studies, support inferences of a causal relationship. Dose-response is an important concept because so many exposures in our ordinary environment can produce adverse effects at very high exposure levels or if exposure occurs consistently over a long period. For this reason, scientists seek to determine the level and period of exposure below which adverse effects do not occur. Epidemiology studies, however, also have inherent limitations because they analyze people in their everyday setting, in which epidemiologists have little control over factors such as differences in individual health, diet, behavior, and inherited traits. In the case of RF exposure, epidemiology studies may be limited in their ability to measure exposure over time. Conversely, in vivo studies expose animals to measured exposures (e.g., RF signals), for a specified and long time period, at levels higher than typical for humans. Laboratory experiments strive to expose animals at the highest level tolerated, to ensure that potential adverse effects are not missed. If adverse effects result, scientists perform subsequent experiments that utilize lower levels of exposure to identify a level below which adverse effects do not occur. In vivo studies have proven valuable for predicting the type of effect an agent may have on health, as well as indicating the relationship between the levels of exposure that are likely to cause the effect (i.e., the dose-response relationship). Finally, in vitro studies are designed to determine whether high levels of exposure under controlled conditions result in change at the cellular level that may lead to disease. The effects seen in these in vitro studies of isolated cells and tissues, however, are not easily extrapolated to what may occur in humans, and thus are extremely limited, particularly when an adverse effect in humans has not been clearly established. 3

11 The main scientific procedures used in a comprehensive weight-of-evidence review to identify and assess effects on health can be summarized as follows: Identification of the relevant scientific data, regardless of direction of the results (positive or negative), to ensure objectivity and allow consideration of replication studies and follow-up studies, rather than just an initial study by one group of researchers. Consideration of data from the three complementary research areas epidemiology studies, animal studies (in vivo), and studies of cells and tissues (in vitro). Since each approach has strengths and weaknesses, evaluating these different types of research together provides a clearer picture of a possible relationship between exposure to a particular agent and disease. Evaluation of the strengths and limitations of each study. As part of the weight-ofevidence review process, each study s design and methods are critically evaluated to determine if and how sample size, study design, experimental error, or other factors may have affected the study s results, and based on these factors, scientists determine the weight that should be placed on the study s findings. Procedures for evaluating epidemiologic research In the past several years, a number of epidemiology studies of exposure to RF fields from broadcast transmitters have been published, and selected ones have been submitted in public comments regarding the proposed KRPI-AM radio station. Each epidemiology study contributes differently to the overall weight of evidence due to the inherent qualities of its study design, the methods used to collect and analyze data, and any errors or limitations that may have occurred by design or inadvertently during the course of the study. A high quality epidemiology study, for example, would consist of a large cohort of subjects that includes an exposed population, and prospective follow-up of all its study participants over a long period to determine the occurrence of disease in that population. The study should include detailed measurements of exposure for each study participant during the relevant periods of 4

12 exposure. This design, called a cohort study, is expensive and time-consuming; thus, other study types such as the case-control design, and other exposure assessment methods, such as distance from the source instead of direct measurements or calculated (modeled) exposures, are also used with a full understanding of their limitations. Case-control studies compare the past exposure of people who have the disease (cases) with past exposure of those who do not have the disease (controls). This type of study also should have a sufficiently large number of participants, high quality exposure assessment, and exhibit characteristics of good study design. The least informative study design is known as an ecological or geographical correlation study, which is an analysis based on aggregated or grouped data to compare rates of disease; it evaluates exposures for aggregated populations rather than individuals. The results presented in an epidemiology study are commonly summarized as an association, a statistical estimate of the relationship between a specific disease and the exposure level for a specific population group (age or sex). These estimates are greatly influenced by the study s methods (e.g., selection and participation rates and measurement of the participants exposure). In fact, much of epidemiologic analysis involves the interpretation of how the methods used to conduct the study and outside factors, not necessarily in the control of the investigators, could have affected the study s statistical findings. An association is a measure of how things vary together, for example, how occurrence of disease varies with the level of exposure. Statistical associations in cohort epidemiology studies are summarized by relative risk (RR) estimates, which is a ratio of the rate of the disease in the exposed group to the rate in the unexposed group. A value of 1.0 indicates that there is no difference in risk of disease between the exposed group and unexposed group, that is, there is no statistical association. A value greater than 1.0 indicates a positive association and a possible risk associated with exposure. A negative association (less than 1.0) indicates that in the population studied, persons with disease had less exposure than persons without the disease. Typically, the exposures that exhibit negative associations are those that have health benefits, such as eating more vegetables, getting more exercise, or use of a specific medication or treatment. 5

13 Case-control studies estimate relative risks with an odds ratio (OR), which compares the odds of exposure among cases to the odds of exposure among controls. An OR equal to 1.0 indicates no association between exposure and disease, and a positive association (OR > 1.0) suggests that participants in the study who developed a disease had more exposure than persons who do not have the disease. For example, an association of 3.0 or more (i.e., the estimated rate of disease is at least three times higher in individuals with the exposure compared to individuals with no exposure), may indicate a strong association. Like any estimate from a sample of the population, these statistical associations in epidemiology studies are subject to the role of chance. This is analogous to a poll taken on a sample of voters, for which chance is expressed as a margin of error. Standard statistical testing is conducted to determine the likelihood that the statistical association is a chance occurrence. The most common expression of statistical certainty in epidemiology studies is the confidence interval (CI), similar to a margin of error. A CI is a range of values for an estimate of effect that has a specified probability (e.g., 95%) of including the true estimate of effect. A 95% CI indicates that, if the study were conducted a very large number of times, 95% of the measured estimates would be within the upper and lower limits of the CI range of values. Differences that are unlikely to be due to chance alone are those in which the 95% CI of an OR or RR does not include the value The results of studies with a small sample size (i.e., those with few participants) are often difficult to distinguish from the random variation that normally occurs in data and typically result in a CI range of values that is wide and imprecise. 6 Larger studies (i.e., those with more participants), typically have a narrower CI range of values, which provides a more robust and stable estimate of an association. 5 6 These risk estimates that do not include 1.0 in the 95% CI range of values may be referred to as statistically significant. See Table 3 in Section IV. 6

14 Chance is one of the factors always considered when evaluating the weight assigned to the statistical association in any epidemiology study. But, if a study reports a statistical association for which chance is not a likely explanation, it is important to assess other factors that may affect the quality and reliability of that study. 1. Chance. A statistical association may simply be due to chance. Statistical tests are performed to evaluate whether chance is a likely explanation. 2. Bias. Bias is any systematic error in the design, implementation, or analysis of a study that results in a mistaken estimate of an exposure s effect on the risk of disease. For example, comparing disease rates between exposed and unexposed groups of different ages may introduce bias if age is related to the disease. 3. Confounding. A confounder is a characteristic that is related to both the disease under study and the exposure of interest such that one cannot separate the effects of them and cannot be sure what causes the observed association the confounder or the exposure of interest. For example, if scientists investigated whether an association existed between alcohol consumption and a specific type of cancer, one would question whether the role of smoking was considered. This is because if those who consumed more alcohol smoked more, which is likely, smoking would have confounded the association with alcohol. When evaluating statistical associations that are reported in epidemiology studies, guidelines referred to as Hill s criteria are used to evaluate the plausibility of a cause-and-effect relationship. The main aspects of these criteria are: Strength: The stronger the association between the disease and the exposure in question, the more persuasive the evidence. Consistency: Consistent results across different study populations and study designs are more convincing than isolated observations. Dose-response: If the risk of disease increases as the exposure level increases (e.g., from low to high exposure), the exposure is more likely to be related to the disease. 7

15 Temporality: The data must provide evidence of correct temporality (time-frame). That is, the exposure must be documented to have occurred before the observed effect and with sufficient time for a disease induction period (i.e., the period it takes for a specific cause to produce disease). Biological Plausibility: Epidemiologic results are much more convincing if they reflect what is known about biology. That is, the evidence is stronger if scientists know of a biological mechanism that can explain the effect. Each criterion cannot be addressed with a simple yes or no, rather, they serve as guidance for weighing the evidence to reach a decision on causality. 8

16 III. Scientific Reviews of Radiofrequency Fields and Health Many national and international scientific and health agencies have conducted comprehensive weight-of-evidence reviews of the research on RF fields and health published in peer-reviewed scientific journals. None of these comprehensive assessments found any persuasive evidence for a health risk from exposures of the general public to RF fields at or below the Federal Communications Commission s (FCC) exposure limits. As explained in letters submitted in this matter by Stephen Lockwood, P.E., of Hatfield and Dawson, 7 broadcasters in the United States are required to comply with FCC regulations (FCC, 1997a; FCC, 1997b), which are based on recommendations from two reviews of the scientific research (NRCP,1986; IEEE, 1991). In Canada, the relevant standard is Safety Code 6 (Health Canada, 2009). Multiple evaluations have been published in the past several years that examine recent research. These evaluations also have not concluded that exposure to RF energy below the exposure limits developed by the FCC or similar exposure limits recommended by the International Commission on Non-ionizing Radiation Protection (ICNIRP) in 2009 or the Institute of Electrical and Electronics Engineers (IEEE) in 2005 causes any type of cancer, other chronic disease, adverse physiologic changes, or symptoms that affect well-being. The Swedish Radiation Safety Authority (SSM), for example, regularly convenes panels of experts to independently review new research on key issues related to health and non-ionizing radiation (both extremely low frequency electric and magnetic fields and higher RF fields). Their 2010 review, which focused on RF field exposure, considered studies published between 2008 and 2010 (as well as studies available ahead of print as e-publications and subsequently published in 2011). 7 Letter from Stephen Lockwood, P.E., dated 10 February 2014, regarding KRPI s Proposed Antenna System and Canadian Safety Code 6 ; Letter from Stephen Lockwood, P.E., dated 15 January 2013 regarding RF Exposure standards for KRPI. 9

17 They concluded the following regarding low level RF exposure from base stations and radio antennas: Available data do not indicate any risks related to exposure to RF from base stations or radio or TV antennas. Taking into account also the low levels of exposure that these sources give rise to, health effects from transmitters are unlikely (SSM, 2010, p. 4). The SSM s 2013 update on key issues, covering the years 2011 and 2012, reached a similar conclusion: Recent research on exposure from transmitters has mainly focused on cancer and symptoms using improved study designs. These new data do not indicate health risks for the general public related to exposure to radiofrequency electromagnetic fields from base stations for mobile telephony, radio and TV transmitters, or wireless local data networks at home or in schools (SSM, 2013, p. 5). The World Health Organization (WHO) continues to refer to the guidelines for exposure limits developed by ICNIRP and the IEEE, which are based on a detailed assessment of the available scientific evidence (WHO, 2011). Along with the SSM, organizations that recently reviewed the data on RF field exposure and health effects are noted in Table 1, as well as the website where these organizations have their reviews available. The only one of these reviews mentioned in comments from the public was the International Agency for Research on Cancer s (IARC) 2013 review, which is addressed below. 10

18 Table 1. Weight-of-evidence reviews of RF fields Organization (Year) Review Link Advisory Group on Non-ionizing Radiation for the Health Protection Agency of the United Kingdom (2012) Health Council of the Netherlands (2009) Health Council of the Netherlands (2011) International Agency for Research on Cancer (2013) International Commission on Nonionizing Radiation Protection (2009) Scientific Committee on Emerging and Newly Identified Health Risks (2009) Swedish Radiation Safety Authority (2010) Swedish Radiation Safety Authority (2013) Health Effects from Radiofrequency Electromagnetic Fields Electromagnetic Fields: Annual Update 2008 Influence of Radiofrequency Telecommunications Signals on Children s Brains (2011) Non-Ionizing Radiation, Part 2: Radiofrequency Electromagnetic Fields Volume 102 Exposure to High Frequency Electromagnetic Fields, Biological Effects and Health Consequences (100 khz 300 GHz) Health Effects of EMF Exposure Recent Research on EMF and Health Risk Seventh Annual Report from SSMs Independent Expert Group on Electromagnetic Fields Research 2013:19 Eighth Report from SSMs Scientific Council on Electromagnetic Fields b_c/ pdf E.pdf 2/mono102.pdf _scenihr/docs/scenihr_o_022.pdf tioner/rapport/stralskydd/2010/201044/ Publikationer/Rapport/Stralskydd/2013/SSM- Rapport pdf The reports issued by these organizations that describe their scientific assessments are lengthy and complex, given the large body of research that is published on this topic. To facilitate the public s understanding, many of these organizations have prepared Fact Sheets and Frequently Asked Questions (FAQs). Table 2 lists the agencies that provide a summary of the information contained in their reports or provide Fact Sheets, FAQs, or released statements regarding RF research and the website where this information is available. 11

19 Table 2. Summaries of RF information for the public Organization (Year) Summary Document Link Federal Communications Commission Federal Communications Commission (2012) International Commission on Non-Ionizing Radiation Protection (2010) Health Protection Agency of Great Britain / Public Health England (2012) International Agency for Research on Cancer (2011) SCENIHR (2009) World Health Organization (2011) FCC Encyclopedia - Radio Frequency Safety Radio Frequency Safety FAQ Fact Sheet on the Guidelines for Limiting Exposure to Time-Varying Electric and Magnetic Fields Published in Health Phys 99(6): , 2010 Understanding Radiation Radio Waves At-a-Glance Press Release No. 208 IARC Classifies Radiofrequency Electromagnetic Fields as Possibly Carcinogenic to Humans Electromagnetic Fields 2009 Update - Summary Electromagnetic Fields and Public Health: Mobile Phones tlf.pdf nderstandingradiation/ataglance/flash_ RadioWaves/ mittees/opinions_layman/en/electromagn etic-fields/ s/fs193/en/index.html 12

20 IV. Evaluation of Materials Submitted and Recent Epidemiology Research The materials submitted in public comments represent only a small and selected sample of the available scientific literature, and therefore are not sufficient to support any conclusion about a causal relationship between RF field exposure and effects on health. As discussed in Sections II and III, conclusions about health effects must be based on a thorough evaluation of the scientific research in its totality, a skilled and time consuming task that has been conducted repeatedly by many different scientific and health agencies. Public policy decisions about health must be based on conclusions derived from a review of the entirety of research rather than on selected studies cherry-picked from the available literature database (USEPA, 2005; IARC, 2006, preamble; SCENIHR, 2012). Public commenters have submitted materials that they may view as supporting concerns about health risks from exposure to the RF energy emitted by AM radio transmitters (see Appendix 1). Despite the availability of numerous comprehensive reviews by national and international scientific organizations that use valid scientific procedures, and Fact Sheets, FAQs, Statements, and Press Releases about RF energy from these organizations, only one was referred to in the submissions (i.e., the Press Release from the IARC issued June 2011), which is discussed below. Rather, the public comment submissions include a review by two individuals, one of whom is a journalist (Levitt and Lai, 2010), the opinions and anecdotal data submitted by an individual in another matter (Robert Sklar), and the unpublished proceedings of a conference (Salzberg conference). 8 In addition, many of the items submitted in the public comments are individual opinions or blog posts rather than comprehensive reports of research published in the scientific literature (e.g., Magda Havas YouTube videos, Robert Sklar s reports, and selected papers from Neil Cherry s writings posted on the internet, which at the very least are outdated). These materials have not been published in the scientific literature, and therefore have not benefited from peer review. 8 While conference proceedings may be prepared by scientists, they often are not peer-reviewed and so provide less weight to the overall evidence. 13

21 Although some peer-reviewed, published scientific studies were submitted, they provide an incomplete picture; these submissions, taken alone, are out of context. They do not address related research on the same issue or address studies that try to replicate the results. A study by Ha et al. (2007), for example, was submitted, but not the authors correction (Ha et al., 2008) or a related study from Germany (Merzenich et al., 2008). Another submission included the study by Michelozzi et al. (2002), which has limitations that detract from drawing conclusions. Similarly incomplete is the inclusion of a scientific paper by Salford (2003) in a list of selected papers on RF health effects, without regard to numerous studies on the same topic that reached different conclusions. The first section below summarizes the recent research on RF fields from AM radio transmitters related to Ha et al. (2007) and Michelozzi et al. (2002) emphasizing the reason why focusing on hand-picked, selected studies can be misleading. The second section provides guidance for interpreting the IARC s recent conclusion that categorized RF energy as 2B possible carcinogen. Epidemiology research on RF energy from radio transmitters focusing on a single study can be misleading A brief summary of epidemiology research about exposure to RF energy from AM radio transmitters illustrates the importance of considering the body of relevant scientific studies regardless of direction of associations. Although public exposure to RF energy from AM radio sources is quite low due to the federal regulations that govern transmitter facilities, research published in the peer-reviewed scientific literature has examined the risk of cancer, particularly leukemia, in adults and in children from exposure to AM radio or TV transmitters. The majority of this research through 2004 consists of epidemiology studies of ecologic design or geographical correlations, which compare cancer rates calculated for geographic areas (at various distances from antenna sources), but do not directly assess exposure of individuals or the individual factors, such as other exposures and personal characteristics that could affect the analysis (e.g., Hocking et al., 1996; Dolk et al., 1997a, 1997b; McKenzie et al., 1998; Cooper et al., 2001; Park et al, 2004). 14

22 Public comments included a geographic correlation study conducted in Italy that measured distance from radio transmitters in concentric circles from the source to estimate exposure (Michelozzi et al., 2002). In the 12-year period studied, one case of childhood leukemia was observed within 2 kilometers of the antennas, for a risk estimate of 6.1, and a 95% CI of This wide and imprecise 95% CI value range reflects the uncertainty that arises from the very small number of cases, as discussed in Section II. The authors noted that they had no detailed information about exposure levels of the population or about how electromagnetic fields vary at increasing distance from the transmitters and also that we analyzed a rare exposure and a rare disease in a small population, and consequently, the power of study is low. The interpretation of these results is constrained by the use of distance as a substitute for measurements or for modeled calculations that better assess RF exposure from the source, and the assumption that all people in an area have the same exposure, and no exposure from other RF sources. The distance measured has limited accuracy because although RF field strength generally decreases with distance from the source, characteristics of the antenna, the topography, and the built environment also affect the level of RF fields that would be measured. Other studies have used the stronger cohort and case-control designs. Two more recent casecontrol epidemiology studies of exposure to RF energy from AM radio transmitters (Ha et al., 2007, 2008; Merzenich et al., 2008) and a cohort study of broadcast transmitters (Hauri et al., 2014) provide more reliable epidemiologic information than the previous geographic correlation studies. These studies estimated RF exposure for each individual participant (individual cases who had childhood leukemia or brain cancer, and healthy individuals, called controls, to serve as a comparison group). Each was a large study that addressed the association between exposures from AM radio transmitters and cancer in children, using calculations based on physical characteristics of antennas and the location of the residence of each participant. The design and results of these studies are summarized in Table 3. The first case-control study discussed, conducted in South Korea in 2007, is the one referenced above that was submitted by the public in this matter (Ha et al., 2007). One of the many analyses in the tables presented in the study showed a weak statistical association with one type of childhood leukemia. This study was followed by a published letter to the editor of the journal 15

23 where the Ha study appeared, noting some problems with the study (Schüz et al, 2008). After this disclosure of the error noted by Schüz et al. (2008), the researchers of the Ha et al. (2007) study revised the exposure analyses and published a correction in the same journal (Ha et al., 2008). Subsequently, another research group published results of a study of similar design that was conducted in Germany (Merzenich et al., 2008). The data from the corrected Korean study (Ha et al., 2008) did not indicate that exposure to RF energy from AM radio transmitters showed a statistically significant association with childhood leukemia, as was suggested by some of the data analyses in the original study (Ha et al., 2007). Neither the corrected Ha et al. (2008) study nor the similar Merzenich et al. (2008) study showed evidence of an increase in disease in those persons with any level of calculated exposure, even at the highest level, to RF fields from all of the AM radio transmitters, thus, these studies do not support a dose-response effect of exposure on the risk of leukemia. The results do not indicate any increase in disease with distance, even in those persons living closest to the transmitters (Merzenich et al., 2008). Epidemiologists in Switzerland modeled RF field strength from broadcast transmitters to identify the rate of new cases of cancer (i.e., the incidence rate) diagnosed for different levels of exposure in a large cohort (Hauri et al., 2014). The cohort included over 1.2 million children under age 16 living in Switzerland between 1985 through 2008, within which 4,246 had been diagnosed with cancer, including 1,326 with leukemia. The exposure assessment modeled RF fields from short wave, medium wave, very-high frequency, and ultra-high frequency radio and TV transmitters for specified output power, which included AM radio transmitters in the medium frequency range like that of KRPI (See Table 3 below, exposure sources). Exposure was assigned to each case based on the RF field strength on their date of diagnosis, using three exposure categories. The analysis adjusted for several factors related to leukemia risk such as exposure to benzene and ionizing radiation including radon gas. Results did not indicate an increased incidence rate related to exposure for all cancers, leukemia, or central nervous system tumors. No differences were seen in the overall time period or in the time period before 1996 when use of cordless phones and mobile phones was less prevalent. No increase in risk was present in higher exposure categories (i.e., no dose-response trend). Table 3 16

24 includes the results for leukemia, the predominant form of childhood cancer, to facilitate comparisons with case-control studies. Table 3 shows risk estimates from these case-control and cohort studies (ORs and RRs) for the highest exposures calculated from the sources. All of these risk estimates are below 1.0, and thus do not indicate an increased risk in those living near the source. The 95% CI range of values includes 1.0, indicating that the risk estimates are not statistically significant (i.e., considering the role of chance, the estimates cannot be distinguished from 1.0 thus, no effect). For comparison, Table 3 includes the risk estimate from the ecological correlation study by Michelozzi et al. (2002). That study reports a risk estimate of 6.1, but the wide 95% CI range of values ( ) indicates that, considering the role of chance, this number cannot be reliably distinguished from 1.0. Table 3 also includes the number of cancer cases in each study to illustrate that the studies with a large number of cases have a smaller, more precise 95% CI range of values. We also reviewed a recent study that examined cancer risks in a small community in Israel in relation to various environmental factors, including exposure to RF fields from radio and cellular transmitters (Atzman et al., 2012). Exposure was estimated by distance between the place of residence and the closest transmitter. No information was provided on the power of the transmitters or whether the sources included AM transmitters, on the estimated exposure ranges in the community, or the years in which the cancers were diagnosed. Although the reported results did not indicate an increased risk of RF for overall cancer (all sites), or for any specific type of cancer, the study is not informative due to the small study population and other limitations in methods. The basics of evaluating epidemiologic data and the Hill criteria (described above) can be applied to the better designed studies of broadcast transmitters and childhood leukemia, summarized in Table 3. The case control and cohort studies included calculated levels of exposure and a large number of cases. The risk estimates for the highest exposure category are consistently below 1.0 in each of these three studies, although they cannot be interpreted as a negative association because the 95% CI range of values includes 1.0 (i.e., the difference 17

25 between the exposed and unexposed groups are likely due to chance). These studies did not provide evidence of a dose- response relationship. The geographical correlation study used distances from the source in concentric circles as a proxy for exposure, and includes only eight cases (Michelozzi et al., 2002). The risk estimate of 6.1 would indicate strong association, but the 95% CI range of values is wide and imprecise, and includes

26 Table 3. Epidemiology studies of radio frequency exposure from broadcast transmitters and childhood leukemia Author (Year) Title Exposure Assessment Method Risk Estimate 95% Confidence Interval Total No. Cases in study Exposure Sources Case Control and Cohort Design Studies Ha et al. (2007) Ha et al. (2008) Merzenich et al. (2008) Hauri et al. (2014) Radio-frequency radiation exposure from AM radio transmitters and childhood leukemia and brain cancer Letter to the editor five authors reply Childhood leukemia in relation to radio frequency electromagnetic fields in the vicinity of TV and radio broadcast transmitters Exposure to radio-frequency electromagnetic fields from broadcast transmitters and risk of childhood cancer: a census-based cohort study Ecological Design Study (geographic correlation) Calculation (quartiles in mv/m) Calculation (quantiles in V/m)* Calculation (3 categories of V/m) OR = ,300 OR = ,959 IRR = ,326 Thirty-one AM radio transmitters, located in South Korea, with a power of 20 kw or more. Results are for all 31 transmitters and peak exposure from the highest source. FM radio and television broadcast transmitters operating between 1983 and Separate analyses were conducted for AM transmitters. Nine short-wave and medium-wave (VHF and UHF) radio transmitters with an output power greater than 1 kw. Eleven VHF and UHF transmitters with an output power of more than 100 kw and 11 transmitters with an output power between 10 kw and 100 kw if more than 30,000 persons lived within a 5-km radius. Michelozzi et al (2002) Adult and childhood leukemia near a high-power radio station in Rome, Italy Distance from radio station (5 bands within 10 km) SIR = Vatican radio station Abbreviations: AM amplitude modulated; FM frequency modulated; IIR incidence rate ratio; km kilometer; kw kilowatts; mv/m millivolts per meter; OR odds ratio; SIR = standardized incidence ratio; UHF ultra high frequency; VHF very high frequency; V/m volts per meter. * Quantiles: 0-90%; 90-95%; %. Risk estimates for Merzenich et al. (2008) and Ha et al. (2007) are based on comparable reference category and high exposure category (Source: Merzenich et al., 2008, Table 5). 1,000 mv/m =1 V/m. 19

27 IARC review of RF energy Public comments submitted in this matter include a press release from the IARC stating that a Working Group of 31 scientists rated the use of mobile phones, which utilize RF fields at high frequencies (800 1,900 MHz), as a possible carcinogen for glioma and acoustic neuroma, two types of brain tumors (IARC, 2011), based on limited evidence. The evidence was rated inadequate to support conclusions for other types of cancer. As stated in the press release, the IARC also critically evaluated the available scientific literature on occupational, environmental, and personal exposure to RF fields and noted that the evidence from occupational and environmental exposures was also inadequate, referring to transmission of signals for radio, television and wireless telecommunication. This is similar to the conclusions reached by the SSM discussed in Section III. In their evaluations, IARC considers two main types of evidence: epidemiology studies and laboratory animal (in vivo) studies. Regarding epidemiology studies of environmental exposures to RF fields from sources like AM radio transmitters, the IARC concluded: Together, these studies provide no indication that environmental exposure to RF radiation increases the risk of brain tumours (IARC, 2013, p. 414). From the limited data available no conclusions could be drawn on the risk of leukaemia or lymphoma from environmental exposure to RF radiation (IARC, 2013, p. 414) The Working Group identified five studies that addressed other malignancies and environmental exposure to RF radiation, and found the available evidence uninformative (IARC, 2013, p. 415) IARC also considered studies in cells and tissues (in vitro studies) to provide additional input on potential mechanisms of action regarding cancer, as well as exposure assessment studies to better understand potential impacts of exposure in our daily life. The IARC applies the weight-of-evidence review process, discussed in Section II, to evaluate potential risk. The category possibly carcinogenic to humans denotes exposures for which there is limited evidence of carcinogenicity in epidemiology studies and less than sufficient 20

28 evidence of carcinogenicity in studies of experimental animals. Other categories include Group 2A probable carcinogen, Group 1 known carcinogen, and Group 3 unclassifiable. For perspective on the IARC classification system, consider that the criteria for the Group 2B rating is very conservative in that it is based on limited and less than sufficient evidence of causation. Group 2B also includes such things as occupation as a firefighter, pickled vegetables, and coffee. Moreover, the IARC classification for RF field exposure in the 2B category is largely based on the review of studies that include heavy and long-term use of mobile phones, which is a far greater source of public exposure than that from AM radio transmitters. Mobile phones are radios with built in antennas, and with each use are the source of the highest intensity of RF fields to the general public. Mobile phone exposures represent the highest RF exposure, or dose scenario, for people in the general population, and therefore, the greatest potential for detecting an adverse response to RF exposure. In a large epidemiology study of mobile phone use and brain cancer, an increase in brain tumors was found only for those who reported over 1,600 hours of use the highest category, which is but a small percentage of those who use mobile phones. (Note, however, that even this association is not necessarily indicative of a causal relationship, as chance, bias, and confounding could not be ruled out as an explanation for the observed association in the study.) The exposure to RF energy during use of a mobile phone is hundreds of times higher than background exposure from AM radio transmitters. Exposures higher than that from mobile phones are used in laboratory animal studies, which have not caused an increase in brain tumors in the animals compared to unexposed animals (IARC, 2013). 21

29 V. Questions Posed by the Whatcom County Staff The Whatcom County staff has asked Are there any associated health risks regarding RF radiation exposure? and What studies, if any are available to show there are no inherent risks? The discussions in the sections above provide scientific evidence to answer these questions. The reviews conducted by numerous national and international health and scientific agencies that assessed the risk of exposure to RF energy found that RF levels in compliance with FCC rules do not pose a risk to human health. This conclusion is based on the most reliable laboratory and epidemiology studies, including studies of laboratory animals exposed to fields of high RF intensity over the animals life span, as well as epidemiology studies of humans exposed to RF energy from AM radio antennas (a relatively low exposure) and RF energy from mobile phones (a relatively higher exposure). The evaluations of the studies considered in the group of weight-of-evidence reviews cited in Section III above show that there is no inherent public health risk associated with the operation of RF sources like the KRPI transmitter. 9 The weight-of-evidence reviews cited in this report in Section III describe the studies relevant for assessing risks, evaluate the strengths and limitations, and identify which in this body of research are most reliable and thus given the most weight in assessing potential risks of exposure. These reviews have led to conclusions that the exposure limits based on scientific research and used in the United States as set by FCC, and the International Commission on Non- Ionizing Radiation Protection (ICNIRP) limits recommended for use by the World Health Organization to fully protect the exposed population. These reviews have studied the research about proposed health effects, such as cancer, purported to occur from long-term exposures at low levels, and have not concluded that they support lowering the FCC or ICNIRP standards. Thus, to assess whether exposure from a given facility is without risk to the exposed members of the public, it is essential to compare the RF intensity created by the AM radio transmitter with the FCC standard. Engineers who have evaluated the project report that the RF level will 9 If exposure to RF fields at the antenna exceeded the occupational exposure limit by a large margin it could pose a known hazard from tissue heating (FCC, 1999). 22