The United States has experienced dramatic changes in mobile phone use since nationwide cellular service became available in the mid-1980s. For example, the number of estimated mobile phone subscribers has grown from about 3.5 million in 1989 to approximately 286 million by the end of 2009, according to the most recent data reported by FCC. Further, the number of Americans who rely exclusively on mobile phones for voice service has increased in recent years. For example, by the end of 2009 over 50 percent of young adults aged 25 to 29 relied exclusively on mobile phones, according to the most recent FCC data. The way individuals use mobile phones has also changed. For instance, while average minutes of use per mobile phone subscriber per month has declined in recent years, mobile text messaging traffic has increased. About 88 percent of teenage mobile phone users now send and receive text messages, which is a rise from the 51 percent of teenagers who texted in 2006. Mobile phones are low-powered radio transceivers—a combination transmitter and receiver—that use radio waves to communicate with fixed installations, called base stations or cell towers. The radio waves used by mobile phones are a form of electromagnetic radiation—energy moving through space as a series of electric and magnetic waves. The spectrum of electromagnetic radiation comprises a range of frequencies from very low, such as electrical power from power lines, through visible light, to extremely high, such as gamma rays, as shown in figure 1. The portion of the electromagnetic spectrum used by mobile phones—as well as other telecommunications services, such as radio and television broadcasting— is referred to as the RF spectrum. The electromagnetic spectrum includes ionizing and non-ionizing radiation. Ionizing radiation, such as gamma rays, has energy levels high enough to strip electrons from atoms and molecules, which can lead to serious biological damage, including the production of cancers. RF energy, on the other hand, is in the non-ionizing portion of the electromagnetic spectrum, which lacks the energy needed to cause ionization. However, RF energy can produce other types of biological effects. For example, it has been known for many years that exposure to high levels of RF energy, particularly at microwave frequencies, can rapidly heat biological tissue. This thermal effect can cause harm by increasing body temperature, disrupting behavior, and damaging biological tissue. The thermal effect has been successfully harnessed for household and industrial applications, such as cooking food and molding plastics. Since mobile phones are required to operate at power levels well below the threshold for known thermal effects, the mobile phone health issue has generally focused on whether there are any adverse health effects from long-term or frequent exposure to low-power RF energy emissions that are not caused by heating. Scientific research to date has not demonstrated adverse human health effects from RF energy exposure from mobile phone use, but additional research may increase understanding of possible effects. In 2001, we reported that FDA and others had concluded that research had not shown RF energy emissions from mobile phones to have adverse health effects, but that insufficient information was available to conclude mobile phones posed no risk. Following another decade of scientific research and hundreds of studies examining health effects of RF energy exposure from mobile phone use, FDA maintains this conclusion. FDA stated that while the overall body of research has not demonstrated adverse health effects, some individual studies suggest possible effects. Officials from NIH, experts we interviewed, and a working group commissioned by IARC— the World Health Organization’s agency that promotes international collaboration in cancer research—have reached similar conclusions. For example, in May 2011 IARC classified RF energy as “possibly carcinogenic to humans.” IARC determined that the evidence from the scientific research for gliomas, a type of cancerous brain tumor, was limited—meaning that an association has been observed between RF energy exposure and cancer for which a causal relationship is considered to be credible, but chance, bias, or confounding factors could not be ruled out with reasonable confidence. With respect to other types of cancers, IARC determined that the evidence was inadequate—meaning that the available studies are of insufficient quality, consistency, or statistical power to permit a conclusion about the causal association. Additionally, in April 2012 an advisory group to the Health Protection Agency—an independent organization established by the United Kingdom government to protect the public from environmental hazards and infectious diseases—concluded that although there is substantial research on this topic, there is no convincing evidence that RF energy below guideline levels causes health effects in adults or children. A broad body of research is important for understanding the health effects of RF energy exposure from mobile phone use, because no single study can establish a cause-and-effect relationship and limitations associated with studies can make it difficult to draw conclusions. Two types of studies, epidemiological and laboratory, are used in combination to examine effects from mobile phones. Epidemiological studies investigate the association, if any, between health effects and the characteristics of people and their environment. Laboratory studies conducted on test subjects—including human volunteers, laboratory animals, biological tissue samples, or isolated cells—are used to determine a causal relationship between possible risk factors and human health, and the possible mechanisms through which that relationship occurs. Studies we reviewed suggested and experts we interviewed stated that epidemiological research has not demonstrated adverse health effects from RF energy exposure from mobile phone use, but the research is not conclusive because findings from some studies have suggested a possible association with certain types of tumors, including cancerous tumors. Findings from one such study, the INTERPHONE study, were published in 2010. This retrospective case-control study with more than 5,000 cases examined the association between mobile phone use and certain types of brain tumors, including cancerous tumors, in individuals aged 30-59 years in 13 countries. Overall study findings did not show an increased risk of brain tumors from mobile phone use, but at the highest level of exposure, findings suggested a possible increased risk of glioma. Other epidemiological studies have not found associations between mobile phone use and tumors, including cancerous tumors. For example, findings from a nationwide cohort study conducted in Denmark that originally followed 420,095 individuals did not show an association between increased risk for certain types of tumors, including cancerous tumors, and mobile phone use. Additionally, findings from a subset of the cohort—56,648 individuals with 10 or more years since their first mobile phone subscription—did not show an increased risk for brain and nervous system tumors. Further, these findings did not change for individuals in the cohort with 13 or more years since their first mobile phone subscription. Also, the CEFALO study—an international case- control study that compared children aged 7 to 19 diagnosed with certain types of brain tumors, including brain cancers, to similar children who were not diagnosed with brain tumors—found no relationship between mobile phone use and risk for brain tumors. Findings from another study, which was conducted by NIH and examined trends in brain cancer incidence rates in the United States using national cancer registry data collected from 1992 to 2006, did not find an increase in new cases of brain cancer, despite a dramatic increase in mobile phone use during this time period. Limitations associated with epidemiological studies can make it difficult to draw definitive conclusions about whether adverse health effects are linked to RF energy exposure from mobile phone use. One such limitation is that it is difficult to measure and control for all variables that may affect results. For example, it can be difficult to accurately measure RF energy exposure from mobile phone use because humans are exposed to RF energy from many sources within their environments and mobile phone technology and user patterns frequently change. Also, epidemiological studies to date have been limited in their ability to provide information about possible effects of long-term RF energy exposure because the prevalence of long-term mobile phone use is still relatively limited and some tumors, including some cancerous tumors, do not develop until many years after exposure. In addition, epidemiological studies, specifically cohort studies, are sometimes limited in their ability to provide information about increased risks for rare outcomes, such as certain types of brain tumors. To address challenges with assessing rare outcomes, case-control studies, which collect information about past mobile phone use among study participants, may be undertaken with large numbers of cases and controls. While these studies can potentially provide information on long-term use, and include enough cancer cases to examine whether this use is associated with rare diseases, collecting data in this way can introduce bias, such as recall bias, into study data and further limit findings. To mitigate this potential bias, some epidemiological studies, specifically cohort studies, follow large populations over time and collect data about mobile phone use before participants develop a certain outcome. In spite of these limitations, experts we spoke with told us that epidemiological studies are a key component of the body of research used for assessing the health effects of mobile phones. Studies we reviewed suggested and experts we interviewed stated that laboratory research has not demonstrated adverse human health effects from RF energy exposure from mobile phone use, but the research is not conclusive because findings from some studies have observed effects on test subjects. Some laboratory studies have examined whether RF energy has harmful effects by exposing samples of human and animal cells to RF energy over a range of dose rates, durations, and conditions to detect any changes in cellular structures and functions. For example, some studies have examined the effects of RF energy on deoxyribonucleic acid (DNA) in rodent and human cells. While some of these studies found that RF energy exposure damaged DNA, others failed to replicate such an effect using similar experimental conditions. Other studies have exposed laboratory animals to RF energy, examined the animals for changes, and compared outcomes with a control group. For example, some studies have measured the behavior or cognitive functioning of rats to assess the neurological effects of RF energy. According to some studies we reviewed, while some of these studies have observed changes in behavior and cognitive function, overall, these studies have not consistently found adverse effects from RF energy levels emitted from mobile phones. Laboratory studies also have exposed human volunteers to RF energy to investigate possible effects, such as effects on the neurological system or blood pressure. According to studies we reviewed, some studies on human volunteers have observed changes, such as changes in brain activity, but the implications of these physiological changes in relation to adverse effects on human health are unknown. Limitations associated with laboratory studies can make it difficult to draw conclusions about adverse human health effects from RF energy exposure from mobile phone use. For example, studies conducted on laboratory animals allow researchers to examine the effects of RF energy exposure on animal systems, but this type of research is limited because effects on laboratory animals may not be the same on humans. Additionally, studies on test subjects may observe biological or physiological changes, but in some circumstances it is unclear how or even if these changes affect human health. Further, to increase the strength of the evidence that observed changes in laboratory studies are the effect of RF energy exposure, studies must be replicated and confirmed with additional research using different dose rates, durations, and conditions of RF energy while observing similar effects. To date, according to FDA officials and some experts we interviewed, only a few laboratory studies that have shown effects from RF energy have been replicated, and some replicated studies have not confirmed earlier results. Studies we reviewed and experts we interviewed identified key areas for additional epidemiological and laboratory studies, and according to experts, additional research may increase understanding of any possible effects. For example, additional epidemiological studies, particularly large long-term prospective cohort studies and case-control studies on children, could increase knowledge on potential risks of cancer from mobile phone use. Also, studies and experts identified several areas for additional laboratory studies. For example, additional studies on laboratory animals as well as human and animal cells examining the possible toxic or harmful effects of RF energy exposure could increase knowledge on potential biological and health effects of RF energy. Further, additional laboratory studies on human and animal cells to examine non-thermal effects of RF energy could increase knowledge of how, if at all, RF energy interacts with biological systems. However, some experts we spoke to noted that, absent clear evidence for adverse health effects, it is difficult to justify investing significant resources in research examining non- thermal effects of RF energy from mobile phone use. Another area identified for additional laboratory research is studies on human volunteers examining the effect of changes in the neurological system, which could help determine if these possible observed changes in neurological functioning from RF energy are adverse effects. In addition to conducting additional research, experts we interviewed reported that the broader body of evidence on RF energy should be re-evaluated when findings from key studies become available, to determine whether additional research in certain areas is still warranted. Current research activities of federal agencies, international organizations, and the mobile phone industry include funding and supporting ongoing research on the health effects of RF energy exposure from mobile phones. NIH is the only federal agency we interviewed that is directly funding ongoing studies on health effects of RF energy from mobile phone use. NIH officials reported that the agency has provided about $35 million for research in this area from 2001 to 2011. (See table 1 for more information on ongoing studies funded by NIH.) Although other federal agencies are not directly funding research in this area, some agencies are providing support for ongoing studies. For example, FDA officials reported that FDA’s National Center for Toxicological Research, with funding provided by NIH as part of the National Toxicology Program, is conducting studies on rat and bovine brain cells to examine whether RF Also, CDC officials reported energy emitted from mobile phones is toxic.that the agency is collaborating with others to conduct ongoing studies in this area. For example, CDC officials reported that one of the agency’s staff is collaborating with researchers in seven countries to conduct additional analyses on data collected through the INTERPHONE study to determine whether occupational exposure to RF energy and chemicals was a risk factor for brain cancer. Federal agencies are also engaged in other activities to support research on the health effects of mobile phone use. For example, FDA collaborates with other organizations on research-related projects. According to FDA officials, the agency helped the World Health Organization develop its WHO Research Agenda for Radiofrequency Fields in 2001 and has provided comments to the World Health Organization on updates to this research agenda.responsibility for different aspects of RF energy safety and work—CDC, EPA, FCC, FDA, NIH, the National Telecommunications and Information Administration, and OSHA—are members of the Radiofrequency Interagency Work Group, which works to share information on RF energy related projects at the staff level. According to FCC and FDA officials, this group periodically meets to discuss RF energy related issues, including recently published and ongoing research on the health effects of RF energy exposure. Also, officials from federal agencies that have International organizations also support research on health effects of RF energy exposure from mobile phone use. Officials from IARC told us that the organization is currently supporting research activities for ongoing studies examining health effects of mobile phone use with respect to cancer. For example, IARC is involved in the identification of research sites for and implementation of the COSMOS study—a large international, prospective, cohort study that will follow individuals for 25 or more years to examine possible long-term health effects of using mobile phones, such as brain tumors, including cancers, and other health outcomes. IARC is also coordinating additional data analyses on previously published studies examining mobile phone health effects. For example, IARC is coordinating additional analyses of data collected for the INTERPHONE study. Additionally, the European Commission—the European Union’s executive body that represents the interest of Europe as a whole—is supporting research in this field. Under its research program—the Seventh Framework Programme—the European Commission has provided funds for the MOBI-KIDS study, an international case-control study examining the possible association between communication technology, including mobile phones and other environmental exposures, and the risk of brain tumors in people aged 10 to 24 years. The mobile phone industry supports research by providing funding for studies. According to representatives from mobile phone manufacturers, service providers, and industry associations, most industry funding for scientific research is provided by the Mobile Manufacturers Forum—an international not-for-profit association that is largely comprised of wireless device manufacturers. According to representatives from the Mobile Manufacturers Forum, the association has provided about $46 million for RF energy research since 2000 and is currently providing support for epidemiological and laboratory studies. Although representatives from all four mobile phone manufacturers that we interviewed reported that their companies support research through their industry associations, representatives from one manufacturer reported that it is also funding two studies examining the effects of RF energy emitted from mobile phones on human hands and the head. In 1996, FCC adopted the RF energy exposure limit for mobile phones of 1.6 watts per kilogram, averaged over one gram of tissue, a measurement of the amount of RF energy absorbed into the body. FCC developed its limit based on input from federal health and safety agencies as well as the 1991 recommendation by the Institute of Electrical and Electronics Engineers (IEEE) that was subsequently approved and issued in 1992 by the American National Standards Institute (ANSI).recommended limit was based on evidence related to the thermal effects This of RF energy exposureexposure—and was set at a level well below the threshold for such effects. FCC noted that the limit provided a proper balance between protecting the public from exposure to potentially harmful RF energy and allowing industry to provide telecommunications services to the public in the most efficient and practical manner possible. —the only proven health effects of RF energy In 2006, IEEE published its updated recommendation for an RF energy exposure limit of 2.0 watts per kilogram, averaged over 10 grams of tissue. exposure from mobile phone use, although actual exposure depends on a number of factors, including the operating power of the phone, how the phone is held during use, and where it is used in proximity to a mobile phone base station. According to IEEE, improved RF energy research and a better understanding of the thermal effects of RF energy exposure on animals and humans, as well as a review of the available scientific research, led to the change in recommended RF energy exposure limit. IEEE’s new recommended limit was harmonized with a 1998 recommendation of the International Commission on Non-Ionizing Radiation Protection, which has been adopted by more than 40 countries, including the European Union countries. Both of these recommendations call for an exposure limit of 2.0 watts per kilogram averaged over 10 grams of tissue, which according to IEEE represents a scientific consensus on RF energy exposure limits. See IEEE Std. C95.1-2005. According to senior FCC officials, the agency has not adopted any newer limit because federal health and safety agencies have not advised them to do so. FCC officials told us that they rely heavily on the guidance and recommendations of federal health and safety agencies when determining the appropriate RF energy exposure limit and that, to date, none of these agencies have advised FCC that its current RF energy limit needs to be revised. Officials from FDA and EPA told us that FCC has not formally asked either agency for an opinion on the RF energy limit. FDA officials noted, though, that if they had a concern with the current RF energy exposure limit, then they would bring it to the attention of FCC. Although federal guidance states that agencies should generally use consensus standards, FCC officials provided reasons why they did not have current plans to change the RF energy exposure limit. Office of Management and Budget Circular A-119 concerning federal use of technical standards states that federal agencies must use “consensus standards in lieu of government-unique standards,” except where inconsistent with law or otherwise impractical. FCC officials noted that no determination has been made that the new recommended RF energy exposure limit is inconsistent with law or impractical. FCC has recognized that research on RF energy exposure is ongoing and pledged to monitor the science to ensure that its guidelines continue to be appropriate. FCC officials noted that an assessment of the current limit and the new recommended limit could be accomplished through a formal rulemaking process, which would include a solicitation of information and opinions from federal health and safety agencies. FCC could alternatively release a Notice of Inquiry to gather information on this issue without formally initiating rulemaking. Stakeholders we spoke with varied on whether the current U.S. RF energy exposure limit should be changed to reflect the new recommended limit. For instance, a few experts and consumer groups we spoke with said FCC should not adopt the new recommended exposure limit because of the relative uncertainty of scientific research on adverse health effects from mobile phone use. An official from one consumer group told us that adopting the 2.0 watts per kilogram exposure limit would be a step back, since it could allow users to be exposed to higher radiation levels. Conversely, some experts we spoke with maintained that both the 1.6- and 2.0-watts-per-kilogram limits protect users from the thermal effects of RF energy exposure—which the experts maintained are the only conclusively demonstrated effects of exposure—since a safety factor of fifty was applied to obtain the limits, meaning that the maximum permitted exposure is a fiftieth of what was determined to be the exposure at which potentially deleterious thermal effects are likely to occur. Nevertheless, by not formally reassessing its current RF energy exposure limit, FCC cannot ensure that it is using a limit that reflects the latest evidence on thermal effects from RF energy exposure, and may impose additional costs on manufacturers and limitations on mobile phone design. FCC’s current limit was established based on recommendations made more than 20 years ago. According to IEEE, the new recommended limit it developed is based on significantly improved RF research and therefore a better understanding of the thermal effects of RF energy exposure. Additionally, three of the four mobile phone manufacturers we spoke with favored harmonization of RF energy exposure limits, telling us that maintaining the separate standards can result in additional costs and may affect phone design in a way that could limit performance and functionality. According to some manufacturers we spoke with, many of their phones are sold in multiple countries. As a result, the manufacturers have to develop and test phones based on different exposure limits, which can require additional resources and slow the time it takes to get new phones into the market. Additionally, one manufacturer indicated that some features are not enabled on phones sold in the United States that are available in other countries to comply with FCC’s current limit. A reassessment by FCC would help it to determine if any changes to the limit are appropriate. FCC ensures compliance with its RF energy exposure limit by certifying all mobile phones sold in the United States. In its application for certification, manufacturers must provide evidence that their mobile phones meet FCC’s RF energy exposure limit. FCC has authorized 23 TCBs in the United States and other countries to review applications that involve evaluation of RF exposure test data and issue certifications on behalf of the agency. TCBs are private organizations that have been accredited to perform these functions. TCBs now perform the majority of mobile phone certifications, with FCC generally only handling the more complex certifications, such as mobile phones with multiple transmitters using third generation and fourth generation technology.illustrates the mobile phone certification process. Representatives from mobile phone manufacturers we spoke with were generally satisfied with how TCBs review and certify mobile phones, but noted that complex certifications handled by FCC can take a long time to process. For instance, since there are generally no established test procedures for new technologies, FCC must work with the manufacturer to develop appropriate procedures by which the agency can determine if the device meets the RF energy exposure limit. According to FCC, part of this review may result in changes to testing guidance. For example, representatives from one manufacturer told us that FCC may take many months to process an application for a newer product. FCC officials told us that over the last 10 years, the average time to review an application submitted directly to the agency has ranged from 45 to 60 days. Representatives from one TCB we spoke with noted that the TCB review can be as short as a week, though FCC does not collect data on how long it takes TCBs to process applications. To ensure that mobile phones comply with FCC’s RF energy exposure limit, manufacturers conduct tests at their own laboratories or have the testing conducted for them by private laboratories. Laboratories must follow standardized FCC testing procedures or work with FCC to develop acceptable alternatives in some complex cases. These procedures require that the SAR be measured to ensure the mobile phone’s compliance with the FCC exposure limit, which was designed to ensure that mobile phones do not expose the public to levels of RF energy that could be potentially harmful. FCC periodically updates the testing procedures as new mobile phone technology is introduced. A typical testing set-up is shown in figure 3. FCC has implemented standardized testing procedures requiring mobile phones to be tested for compliance with the RF energy exposure limit when in use against the ear and against the body while in body-worn accessories, such as holsters, but these requirements may not identify the maximum exposure under other conditions. The specific minimum separation distance from the body is determined by the manufacturer (never to exceed 2.5 centimeters), based on the way in which the mobile phone is designed to be used. The results of these testing requirements are two different values: a maximum SAR value for the head and a maximum SAR value for the body. However, these testing procedures may not identify the maximum SAR for the body, since some consumers use mobile phones with only a slight distance, or no distance, between the device and the body, such as placing the phone in a pocket while using an ear piece. Using a mobile phone in this manner could result in RF energy exposure above the maximum body-worn SAR determined during testing, although that may not necessarily be in excess of the FCC’s limit. In such a case, exposure in excess of FCC’s limit could occur if the device were to transmit continuously and at maximum power. FCC has not reassessed its testing requirements to ensure that testing identifies the maximum RF energy exposure for the other usage conditions a user could experience when mobile phones are in use without body-worn accessories or as advised by the manufacturer’s instructions, rather than the head. Although FCC officials said that they provide case-by-case guidance for many mobile phones operating with new technologies, they do not require testing of mobile phones when used without body-worn accessories unless such conditions are specifically identified by the manufacturer’s operating instructions. Representatives of some consumer groups we spoke with expressed concern about the exposure to RF energy that can come with such use. Officials from IEEE, though, told us that the average power and resultant radiation level of mobile phones while in use is very low, such that even when a mobile phone is used against the body it is unlikely that the RF energy exposure would exceed the FCC limit. Nevertheless, FCC has not reassessed its testing requirements to ensure that mobile phones do not exceed the RF energy exposure limit in all possible usage conditions. Beyond the testing required for certification, FCC also ensures that mobile phones meet its RF energy exposure limit by reviewing information collected as part of routine surveillance of mobile phones on the market. FCC requires TCBs to carry out this post-market surveillance program, through which each TCB tests one percent of the mobile phones they have certified for RF energy exposure, to ensure that the phones continue to meet FCC’s RF energy exposure limit. According to FCC, no mobile phone tested under this surveillance program has been found in violation of the RF energy exposure limit. Federal agencies provide information to the public on the health effects of mobile phone use and related issues primarily through their websites. This information includes summaries of research, and agencies’ conclusions about the health effects of mobile phone use, as well as suggestions for how mobile phone users can reduce their exposure to RF energy. Table 2 summarizes selected information on mobile phones and health provided by six federal agencies on their websites. The types of information that federal agencies’ websites provide on mobile phone health effects and related issues vary, in part because of the agencies’ different missions, though the websites provide a broadly consistent message. For instance, NIH primarily provides information about the research on health effects of RF energy exposure from mobile phone use, while FCC provides information on how mobile phones are tested and certified. Nevertheless, the concluding statements about whether RF energy exposure from mobile phone use poses a risk to human health are generally consistent across selected federal agencies’ websites that we reviewed, though the specific wording of these concluding statements varies. Representatives from some consumer groups and experts we spoke with raised concerns that the information on federal agency websites about mobile phone health effects is not precautionary enough, among other things. In particular, these representatives and experts said that federal agencies should include stronger precautionary information about mobile phones because of the uncertain state of scientific research on mobile phone health effects as well as the fact that current testing requirements may not identify the maximum possible RF energy exposure. Representatives from one consumer group also said that federal agency websites should provide more consumer information, such as the impact of different mobile phone technologies on RF energy exposure. Officials from FCC and NIH maintained that the information on their websites reflects the latest scientific evidence and provides sufficient information for consumers concerned about potential health effects related to mobile phones. Some consumer groups noted that they would like FCC to mention IARC’s recent classification of RF energy exposure as “possibly carcinogenic” on FCC’s website. FCC noted that it generally defers to the health and safety agencies for reporting on new research, though FCC’s website did include information on the recent INTERPHONE study when we reviewed the site in June 2012. FCC does provide links to CDC, EPA, FDA, and other websites, some of which have information about the IARC’s classification. FDA notes on its website that the IARC classification means there is limited evidence showing RF carcinogenicity in humans and insufficient evidence of carcinogenicity in experimental animals. Some local governments are taking steps to provide precautionary information to consumers. For example, the city of San Francisco has developed a Web page on mobile phone health issues, including steps to reduce RF energy exposure from mobile phone use, and has passed an ordinance requiring local mobile phone retailers to distribute a flyer on ways that consumers can reduce their exposure. The mobile phone industry provides information to consumers on the health effects of mobile phone use and related issues through user manuals and websites. The information provided in user manuals by manufacturers is voluntary, as there are no federal requirements that manufacturers provide any specific information to consumers about the Most manuals we reviewed provide health effects of mobile phone use.information about how the device was tested and certified, as well as the highest energy exposure measurement associated with the device. Some manufacturers also provide suggestions, often based on information from FDA, to consumers about how to minimize their exposure, among other things. All manuals we reviewed, except one, include a statement that, when used on the body, as opposed to against the ear, a minimum distance between the body and the mobile phone should be maintained. These distances ranged from 1.5 to 2.5 centimeters. Since all mobile phones are tested for RF energy exposure compliance at a distance from the body, as discussed previously in this report, these instructions are consistent with how the devices were tested and certified by FCC. Some consumer groups and experts we spoke with noted that consumers could be unaware of these instructions if they do not read the entire user manual. FCC’s current RF energy exposure limit for mobile phones, established in 1996, may not reflect the latest evidence on the thermal effects of RF energy exposure and may impose additional costs on manufacturers and limitations on mobile phone design. FCC regulates RF energy emitted from mobile phones and relies on federal health and safety agencies to help determine the appropriate RF energy exposure limit. However, FCC has not formally asked FDA or EPA for their assessment of the limit since 1996, during which time there have been significant improvements in RF energy research and therefore a better understanding of the thermal effects of RF energy exposure. This evidence has led to a new RF energy exposure limit recommendation from international organizations. Additionally, maintaining the current U.S. limit may result in additional costs for manufacturers and impact phone design in a way that could limit performance and functionality. Reassessing its current RF energy exposure limit would ensure that FCC’s limit protects the public from exposure to RF energy while allowing industry to provide telecommunications services in the most efficient and practical manner possible. The current testing requirements for mobile phones may not identify the maximum RF energy exposure when tested against the body. FCC testing requirements state that mobile phone tests should be conducted with belt-clips and holsters attached to the phone or at a predetermined distance from the body. These requirements were developed by FCC to identify the maximum RF energy exposure a user could experience when using a mobile phone, to ensure that the mobile phone meets the agency’s RF energy exposure limit. This limit was designed to ensure that mobile phones do not expose the public to levels of RF energy that could be potentially harmful. By testing mobile phones only when at a distance from the body, FCC may not be identifying the maximum exposure, since some users may hold a mobile phone directly against the body while in use. Using a mobile phone in this manner could result in RF energy exposure above the maximum body-worn SAR determined during testing, although that may not necessarily be in excess of FCC’s limit. Reassessing its testing requirements would allow FCC to ensure that phones used by consumers in the United States do not result in RF energy exposure in excess of FCC’s limit. We recommend that the Chairman of the FCC take the following two actions: Formally reassess the current RF energy exposure limit, including its effects on human health, the costs and benefits associated with keeping the current limit, and the opinions of relevant health and safety agencies, and change the limit if determined appropriate. Reassess whether mobile phone testing requirements result in the identification of maximum RF energy exposure in likely usage configurations, particularly when mobile phones are held against the body, and update testing requirements as appropriate. We provided a draft of this report to the Department of Commerce, Department of Defense, Department of Health and Human Services, Department of Labor, EPA, and FCC for review and comment. FCC provided comments in a letter from the Chief, Office of Engineering and Technology. (See app. III.) In this letter, FCC noted that FCC's staff has independently arrived at the same conclusions about the RF exposure guidelines as GAO. FCC also noted that a draft Order and Further Notice of Proposed Rulemaking, along with a new Notice of Inquiry, which has been submitted by FCC staff to the Commission for their consideration, has the potential to address the recommendations made in this report. We agree that FCC’s planned actions may address our recommendations. However, since FCC has not yet initiated a review of the RF energy exposure limit or mobile phone testing requirements, our recommendations are still relevant. FCC and the Departments of Commerce, Defense, and Health and Human Services also provided technical comments, which were incorporated as appropriate. The Department of Labor and EPA did not provide comments on the draft. As agreed with your office, unless you publicly announce the contents of this report earlier, we plan no further distribution until 30 days from the report date. At that time, we will send copies of this report to the appropriate congressional committees, the Chairman of the FCC, the Administrator of the EPA, as well as the Secretaries of the Departments of Commerce, Defense, Health and Human Services, and Labor. The report will also be available at no charge on GAO’s website at http://www.gao.gov. If you or your staff have any questions or would like to discuss this work, please contact Mark Goldstein at (202) 512-2834 or goldsteinm@gao.gov or Marcia Crosse at (202) 512-7114 or crossem@gao.gov. Contact points for our Offices of Congressional Relations and Public Affairs may be found on the last page of this report. Individuals making key contributions to this report are listed in appendix IV. To determine what is known about the human health effects of radio- frequency (RF) energy exposure from mobile phone use, we reviewed selected studies including studies and reports that review and assess the scientific research, such as meta-analyses and government reports, as well as key individual epidemiological and laboratory studies. We identified 384 studies that examine the health effects of RF energy emitted from mobile phone use through literature searches and interviews. We conducted literature searches in six online databases with health and engineering content—Embase, Inspec, Medline, National Technical Information Service Bibliographic, SciSearch, and SocialSciSearch—containing peer-reviewed publications and government reports to identify studies published from January 2006 through September 2011 using health-, mobile phone-, and RF energy-related search terms. Additionally, we interviewed officials from federal agencies and representatives of academic institutions, consumer groups, and industry associations to identify studies published through December 2011. To select studies for our review, we conducted a preliminary review of the 384 studies and included those that met the following criteria: (1) reviewed and assessed the scientific research in a systematic way, such as meta-analyses, and discussed their methods for identifying, selecting, and assessing the scientific research that were used to draw conclusions or (2) were key reports that identify areas for additional research in these fields, such as the 2008 National Research Council’s Identification of Research Needs Relating to Potential Biological or Adverse Health Effects of Wireless Communication. We selected 38 studies that met these criteria. (See app. II for a list of the 38 studies we reviewed.) To collect information on the 38 selected studies, we developed a data collection instrument that contained 16 open- and closed-ended questions about the entity or entities that published and funded the study; the study methods, key findings, and limitations; and additional research needs. To apply this data collection instrument, one analyst reviewed each study and recorded information in the data collection instrument. A second analyst then reviewed each completed data collection instrument to verify the accuracy of the information recorded. We summarized the findings and limitations of studies based on the completed data collection instruments, as well as areas for additional research identified in the studies. Additionally, we used this analysis to identify key, individual, epidemiological and laboratory studies. We also interviewed subject matter experts to determine what is known about the human health effects of RF energy exposure from mobile phone use. First, we identified 123 potential subject matter experts to interview through the following sources: (1) interviews with officials from federal agencies and representatives of academic institutions, consumer groups, and industry associations and (2) participant lists of recent expert panels and workgroups on this topic. These panels and workgroups included: The National Research Council’s Committee on Identification of Research Needs Relating to Potential Biological or Adverse Health Effects of Wireless Communications Devices, The International Agency for Research on Cancer’s (IARC) Monograph Working Group on RF electromagnetic fields, The INTERPHONE Study Group, The European Commission’s Scientific Committee on Emerging and Newly Identified Health Risks. Baan, R., et al, “Carcinogenicity of Radiofrequency Electromagnetic Fields,” Lancet Oncology, 2011, 12(7): 624-626. The INTERPHONE study is a retrospective case-control study that examined effects of mobile phone use on certain types of brain cancers or tumors in more than 5,000 cases aged 30-59 years in 13 countries. See Cardis, E, et al, “Brain Tumor Risk in Relation to Mobile Telephone Use: Results of the INTERPHONE International Case-Control Study,” International Journal of Epidemiology, 2010, 39: 675-694. European Commission, Health Effects of Exposure to EMF, 2009. least one source and we had information on their general area of expertise or (2) were identified through at least two sources regardless of whether we had information on their general area of expertise. We received responses from 42 experts agreeing to help us with our study. Based on these responses, we selected a judgmental sample of 11 experts who represented a range of expertise and professional backgrounds including public health and policy; biology and medicine; biostatistics; epidemiology; engineering, including bioelectrical engineering; and RF energy standards. (See table 3 for the list of individuals interviewed.) These experts were interviewed as individuals, not as representatives of any institution. Further, all of the experts completed a form stating that they had no conflicts of interest that would affect their ability to provide us with their perspectives on what is known about the human health effects of RF energy exposure from mobile phone use and related issues. To determine the current research activities of federal agencies and other organizations related to mobile phone use and health, we interviewed representatives from various agencies and organizations. We identified agencies and organizations by reviewing information on their websites on RF energy and conducting interviews with officials from federal agencies and representatives of organizations familiar with research on health effects of mobile phone use. To determine the current research activities of federal agencies related to mobile phone use and health, we interviewed officials from the Department of Defense; Department of Health and Human Services’ Centers for Disease Control and Prevention (CDC), Food and Drug Administration (FDA), and National Institutes of Health (NIH); Department of Labor’s Occupational Safety and Health Administration (OSHA); Environmental Protection Agency (EPA); and Federal Communications Commission (FCC). To determine the research activities of other organizations, we interviewed representatives from IARC, academic institutions, consumer groups, mobile phone industry associations, mobile phone manufacturers, and mobile phone providers. To determine how FCC set the RF energy exposure limit and ensures compliance with it, we reviewed and summarized FCC regulations and guidance as well as reports from international organizations that recommend RF energy exposure limits. We also reviewed and summarized FCC testing and certification regulations and guidance for mobile phones. We conducted interviews with officials from FCC and representatives from selected Telecommunication Certification Bodies (TCBs). We selected the four TCBs that approved the most mobile phone certification applications for fiscal years 2000-2011 according to FCC: PCTEST Engineering Laboratory, Inc.; ACB, Inc.; CETECOM ICT Services GmbH; and Timco Engineering, Inc. These four TCBs have approved 69 percent of all U.S. mobile phone applications since 2000. We interviewed representatives from National Institute of Standards and Technology, American National Standards Institute, and American Association for Laboratory Accreditation to discuss their role in accrediting entities as TCBs and monitoring the activities of current TCBs. We also conducted interviews with representatives of the mobile phone industry and consumer groups for their perspectives on RF energy exposure limits as well as the testing and certification of mobile phones. Representatives of the mobile phone industry we spoke with included industry associations (CTIA-The Wireless Association and Mobile Manufacturers Forum) as well as the top four mobile phone service providers (AT&T, Sprint, T-Mobile, and Verizon) that represent about 90 percent of U.S. mobile phone service subscribers. We also spoke with representatives from four mobile phone manufacturers that represent over 70 percent of the U.S. market (LG, Motorola, Nokia, and Samsung). To determine the actions federal agencies and the industry take to inform the public about issues related to mobile phone health effects, we reviewed the information on federal agency websites. We identified six federal agencies that have information about mobile phones and health- related issues on their websites: CDC, EPA, FCC, FDA, NIH, and OSHA. We conducted interviews with officials from those federal agencies to learn how they developed and update their websites. We spoke with representatives of the mobile phone industry noted above and consumer groups to obtain perspectives on the strengths and limitations of federal agency public-information-sharing efforts. We also spoke with the representatives of the mobile phone industry about how and why manufacturers include warnings or specific usage guidelines in their user manuals. Finally, we reviewed the user manuals of selected mobile phones (see table 4) to identify the usage and health information being provided to consumers, including any instructions to hold the mobile phone away from the body during use. The specific mobile phone models were identified by the manufacturers we spoke with as their top selling models in 2011. Ahlbom, Anders, Maria Feychting, Adele Green, Leeka Kheifets, David A. Savitz, and Anthony J. Swerdlow. “Epidemiological Evidence on Mobile Phones and Tumor Risk: A Review.” Epidemiology, vol. 20, no. 5 (2009): 639-652. Balbani, Aracy Pereira Silveira, and Jair Cortez Montovani. “Mobile Phones: Influence on Auditory and Vestibular Systems.” Brazilian Journal of Otorhinolaryngology, vol 74, no. 1 (2008): 125-131. Clapp, Richard W., Molly M. Jacobs, and Edward L. Loechler. “Environmental and Occupational Causes of Cancer: New Evidence 2005-2007.” Reviews on Environmental Health, vol. 23, no. 1 (2008): 1- 37. Committee on Man and Radiation. “COMAR Technical Information Statement: Expert Reviews on Potential Health Effects of Radiofrequency Electromagnetic Fields and Comments on the Bioinitiative Report.” Health Physics, vol. 97, no. 4 (2009): 348-356. Edumed Institute for Medicine and Health. Non-Ionizing Electromagnetic Radiation in the Radiofrequency Spectrum and its Effects on Human Health. Latin American Experts Committee on High Frequency Electromagnetic Fields and Human Health. June 2010. European Health Risk Assessment Network on Electromagnetic Fields Exposure. “Risk Analysis of Human Exposure to Electromagnetic Fields.” Deliverable Report D2, Executive Agency for Health and Consumers Framework of the Programme of Community Action in the Field Of Health 2008-2013. July 2010. European Health Risk Assessment Network on Electromagnetic Fields Exposure. “D3 – Report on the analysis of risks associated to exposure to EMF: in vitro and in vivo (animals) studies.” July 2010. French Environmental Health and Safety Agency. “AFSSE Statement on Mobile Phones and Health.” AFSSE. April 16, 2003. German Mobile Telecommunication Research Programme. “Health Risk Assessment of Mobile Communications.” Department Radiation Protection and Health. Germany: 2008. Habash, Riadh W.Y., J. Mark Elwood, Daniel Krewski, W. Gregory Lotz, James P. McNamee, and Frank S. Prato. “Recent Advances in Research On Radiofrequency Fields and Health: 2004-2007.” Journal of Toxicology and Environmental Health, Part B, vol. 12 (2009): 250-288. Han, Yueh-Ying, Hideyuki Kano, Devra L. Davis, Ajay Niranjan, and L. Dade Lunsford. “Cell Phone Use and Acoustic Neuroma: The Need for Standardized Questionnaires and Access to Industry Data.” Surgical Neurology, vol. 72 (2009): 216-222. Health Council of the Netherlands. “Electromagnetic Fields: Annual Update 2008.” The Hague: Health Council of the Netherlands, 2008; publication no. 2009/02. HERMO. Health Risk Assessment of Mobile Communications. A Finnish Research Programme. Finland: 2007. Institution of Engineering and Technology. “The Possible Harmful Biological Effects of Low-Level Electromagnetic Fields of Frequencies up to 300 GHz.” 2010 Position Statement, Institution of Engineering and Technology. United Kingdom: 2010. International Commission on Non-Ionizing Radiation Protection. Exposure to high frequency electromagnetic fields, biological effects and health consequences (100 kHz-300 GHz). Germany: 2009. Juutilainen, Jukka, Anne Höytö, Timo Kumlin, and Jonne Naarala. “Review of Possible Modulation-Dependent Biological Effects of Radiofrequency Fields.” Bioelectromagnetics, vol. 35 (2011): 511-534. Khurana, Vini G., Charles Teo, Michael Kundi, Lennart Hardell, and Michael Carlberg. “Cell Phones and Brain Tumors: A Review Including the Long-Term Epidemiological Data.” Surgical Neurology, vol. 72 (2009): 205-215. Kohli, D., A. Sachdev, and H. Vats. “Cell Phones and Tumor: Still In No Man’s Land.” Indian Journal of Cancer, vol. 46, no. 1 (2009): 5-12. Kundi, Michael. “The Controversy About a Possible Relationship Between Mobile Phone Use and Cancer.” Ciencia & Saude Coletiva, vol. 15, no. 5 (2010): 2415-2430. Levis, Angelo G., Nadia Minicuci, Paolo Ricci, Valerio Gennaro, and Spiridione Garbisa. “Mobile Phones and Head Tumours. The Discrepancies in Cause-Effect Relationships in the Epidemiological Studies – How Do They Arise?” Environmental Health, vol. 10, no. 59. (2011): 1-15. Marino, Andrew A., and Simona Carrubba. “The Effects of Mobile-Phone Electromagnetic Fields of Brain Electrical Activity: A Critical Analysis of the Literature.” Electromagnetic Biology and Medicine, vol. 28 (2009): 250-274. McKinlay, A.F., S.G. Allen, R. Cox, P.J. Dimbylow, S.M. Mann, C.R. Muirhead, R.D. Saunders, Z.J. Sienkiewicz, J.W. Stather, and P.R. Wainwright. “Advice on Limiting Exposure to Electromagnetic Fields (0- 300 GHz).” Documents of the NRPB, vol. 15, no. 2. National Radiological Protection Board, 2004. Mobile Telecommunications and Health Research Programme. “Report 2007.” United Kingdom: October 2007. Myung, Seung-Kwon, Woong Ju, Diana D. McDonnell, Yeon Ji Lee, Gene Kazinets, Chih-Tao Cheng, and Joel M. Moskowitz. “Mobile Phone Use and Risk of Tumors: A Meta-Analysis” Journal of Clinical Oncology, vol. 27, no. 33 (2009): 5565-5572. National Council on Radiation Protection and Measurements. “Biological Effects of Modulated Radiofrequency Fields.” NCRP Commentary, no. 18. Bethesda, MD: 2003. National Research Council. Identification of Research Needs Relating to Potential Biological or Adverse Health Effects of Wireless Communication. Washington, D.C.: 2008. Nieden, Anja zur, Corrina Dietz, Thomas Eikmann, Jürgen Kiefer, and Caroline E.W. Herr. “Physicians Appeals On the Dangers of Mobile Communication – What Is the Evidence? Assessment of Public Health Data.” International Journal of Hygiene and Environmental Health, vol. 212 (2009): 576-587. Pourlis, Aris F., “Reproductive and Developmental Effects of EMF in Vertebrate Animal Models.” Pathophysiology, vol. 16 (2009): 179-189. Regel, Sabine J., and Peter Achermann. “Cognitive Performance Measures in Bioelectromagnetic Research – Critical Evaluation and Recommendations.” Environmental Health, vol. 10, no. 10 (2011). Röösli, Martin, and Kerstin Hug. “Wireless Communication Fields and Non-Specific Symptoms of Ill Health: A Literature Review.” Weiner Medizinische Wochenschrift, vol. 161, no. 9-10 (2011): 240-250. Scientific Committee on Emerging and Newly Identified Health Risks. Health Effects of Exposure to EMF. European Commission. January 19, 2009. Sixth Framework Programme. “EMF-NET: Effects of the Exposure to Electromagnetic Fields: From Science to Public Health and Safer Workplace.” WP2.2 Deliverable report D4bis: Effects on Reproduction and Development. Italy: 2007. Swedish Radiation Protection Authority. Recent Research on EMF and Health Risks Fifth Annual Report from SSI:s Independent Expert Group on Electromagnetic Fields, 2007, Sweden: 2008. Swedish Radiation Safety Authority. Recent Research on EMF and Health Risk Seventh Annual Report from SSM:s Independent Expert Group on Electromagnetic Fields, 2010. Sweden: 2010. Valentini, E., G. Curcio, F. Moroni, M. Ferrara, L. De Gannaro, and M. Bertini. “Neurophysiological Effects of Mobile Phone Electromagnetic Fields on Humans: A Comprehensive Review.” Bioelectromagnetics, vol. 28 (2007): 415-432. Vanderstraeten, Jacques, and Luc Verschaeve. “Gene and Protein Expression Following Exposure to Radiofrequency Fields from Mobile Phones.” Environmental Health Perspectives, vol. 116, no. 9 (2008): 1131-1135. Vijayalaxmi, and Thomas J. Prihoda. “Genetic Damage in Mammalian Somatic Cells Exposed to Radiofrequency Radiation: A Meta-Analysis of Data from 63 Publications (1990-2005).” Radiation Research, vol.169 (2008): 561-574. World Health Organization. WHO Research Agenda for Radiofrequency Fields. Switzerland: 2010. In addition to the contacts named above, Janina Austin and Teresa Spisak, Assistant Directors, as well as Kyle Browning, Owen Bruce, Marquita Campbell, Leia Dickerson, Kristin Ekelund, Lorraine Ettaro, Colin Fallon, David Hooper, Rosa Leung, and Maria Stattel made key contributions to this report.

Summary: The rapid adoption of mobile phones has occurred amidst controversy over whether the technology poses a risk to human health as a result of long-term exposure to RF energy from mobile phone use. FCC and FDA share regulatory responsibilities for mobile phones. GAO was asked to examine several issues related to mobile phone health effects and regulation. Specifically, this report addresses (1) what is known about the health effects of RF energy from mobile phones and what are current research activities, (2) how FCC set the RF energy exposure limit for mobile phones, and (3) federal agency and industry actions to inform the public about health issues related to mobile phones, among other things. GAO reviewed scientific research; interviewed experts in fields such as public health and engineering, officials from federal agencies, and representatives of academic institutions, consumer groups, and the mobile phone industry; reviewed mobile phone testing and certification regulations and guidance; and reviewed relevant federal agency websites and mobile phone user manuals. Scientific research to date has not demonstrated adverse human health effects of exposure to radio-frequency (RF) energy from mobile phone use, but research is ongoing that may increase understanding of any possible effects. In addition, officials from the Food and Drug Administration (FDA) and the National Institutes of Health (NIH) as well as experts GAO interviewed have reached similar conclusions about the scientific research. Ongoing research examining the health effects of RF energy exposure is funded and supported by federal agencies, international organizations, and the mobile phone industry. NIH is the only federal agency GAO interviewed directly funding studies in this area, but other agencies support research under way by collaborating with NIH or other organizations to conduct studies and identify areas for additional research. The Federal Communications Commissions (FCC) RF energy exposure limit may not reflect the latest research, and testing requirements may not identify maximum exposure in all possible usage conditions. FCC set an RF energy exposure limit for mobile phones in 1996, based on recommendations from federal health and safety agencies and international organizations. These international organizations have updated their exposure limit recommendation in recent years, based on new research, and this new limit has been widely adopted by other countries, including countries in the European Union. This new recommended limit could allow for more RF energy exposure, but actual exposure depends on a number of factors including how the phone is held during use. FCC has not adopted the new recommended limit. The Office of Management and Budgets instructions to federal agencies require the adoption of consensus standards when possible. FCC told GAO that it relies on the guidance of federal health and safety agencies when determining the RF energy exposure limit, and to date, none of these agencies have advised FCC to change the limit. However, FCC has not formally asked these agencies for a reassessment. By not formally reassessing its current limit, FCC cannot ensure it is using a limit that reflects the latest research on RF energy exposure. FCC has also not reassessed its testing requirements to ensure that they identify the maximum RF energy exposure a user could experience. Some consumers may use mobile phones against the body, which FCC does not currently test, and could result in RF energy exposure higher than the FCC limit. Federal agencies and the mobile phone industry provide information on the health effects of mobile phone use and related issues to the public through their websites and mobile phone manuals. The types of information provided via federal agencies websites on mobile phone health effects and related issues vary, in part because of the agencies different missions, although agencies provide a broadly consistent message. Members of the mobile phone industry voluntarily provide information on their websites and in mobile-phone user manuals. There are no federal requirements that manufacturers provide information to consumers about the health effects of mobile phone use. FCC should formally reassess and, if appropriate, change its current RF energy exposure limit and mobile phone testing requirements related to likely usage configurations, particularly when phones are held against the body. FCC noted that a draft document currently under consideration by FCC has the potential to address GAOs recommendations