According to NRC’s website, radiation doses, such as those received by survivors of the atomic bombs in Japan, can cause cancers such as leukemia and colon cancer and, if levels are high enough, acute radiation syndrome. The symptoms of this syndrome range from nausea, fatigue, and vomiting to death within days or weeks. The higher the radiation dose, the sooner the effects of radiation will appear, and the higher the probability of death. For example, according to NRC’s website, 134 of the plant workers and firefighters battling the fire at the 1986 Chernobyl nuclear power plant accident received high doses of radiation and suffered from acute radiation syndrome. Of these, 28 died within the first 3 months from their radiation injuries. In contrast, the effects of low-dose radiation are more difficult to detect. In particular, below about 100 millisieverts (mSv) (10 rem)—the level below which the National Academies’ 2006 report on radiation and human health considered radiation to be low dose—data do not definitively establish the dose-response relationship between cancer and radiation exposure. It is often not possible to determine the extent to which a health outcome such as cancer is caused by low dose radiation because of the potential confounding effects of other chemical and physical hazards and lifestyle factors, such as smoking and diet. In addition, much of the data on health effects of radiation exposure come from non-U.S. populations, such as Japanese atomic bomb survivors, who received a large exposure to radiation over a short period of time (an acute exposure), and there is uncertainty about the extent to which the health effects for these populations can be extrapolated to a U.S. population that is regularly (chronically) exposed to low-dose radiation. The roles of federal agencies in developing and applying radiation protection requirements and guidance vary depending on the setting in which radiation exposure occurs. For the four settings in our review— operation and decommissioning of nuclear power plants, cleanup of sites with radiological contamination, use of medical equipment that produces radiation, and accidental or terrorism-related exposure to radiation—the key agencies for establishing dose limits and guidance levels are EPA, NRC, DOE, and FDA. EPA advises federal agencies about radiation matters that affect public health and provides technical information for conducting radiation risk assessments; federal and state agencies use such assessments to develop and implement radiation protection regulations and standards. EPA also develops requirements and guidance for particular settings in which radiation exposure can occur. For example, EPA has developed regulations to limit discharges of radioactive material affecting members of the public from operations associated with use of nuclear energy to produce electrical power for public use, such as nuclear power plants. In addition, EPA has developed guidance on establishing protective cleanup levels for radioactive contamination at sites cleaned up under the Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA). It has also developed guidance on levels of radiation exposure that would trigger public safety measures, such as evacuation, to minimize or prevent radiation exposure during an emergency. NRC is responsible for protecting people and the environment from unnecessary exposure to radiation as a result of civilian uses of nuclear materials. Among other things, NRC has established dose limits for workers and the public exposed to radiation from the operation and decommissioning of nuclear power plants, as well as minimum requirements for emergency plans for protecting members of the public from exposure in the event of a radiological emergency. NRC also has the primary responsibility for licensing, inspecting, and regulating medical uses of nuclear material. DOE is responsible for ensuring that its facilities are managed to protect workers and the public. As part of this responsibility, DOE has established radiation dose limits for workers at its facilities and public dose limits for DOE radiological activities, including cleanup of radioactive contamination at DOE sites. In addition, under the Atomic Energy Act of 1954, DOE is the federal agency that currently has primary responsibility for research related to nuclear energy. This responsibility includes the protection of health during activities that can result in exposure to radiation. DOE addresses this requirement through research to determine if DOE workers and people living in communities near DOE sites are adversely affected by exposures to hazardous materials from site operations. DOE’s National Nuclear Security Administration (NNSA) assists in emergency response to accidental or terrorism-related exposure to radiation by characterizing radiation levels in the area of an accident or terrorist event and providing information to emergency-response decision makers. FDA has issued radiation safety regulations for medical equipment, such as diagnostic X-ray systems. According to FDA officials, FDA’s regulations generally do not limit the dose to the patient but instead prescribe mandatory performance standards for most radiology medical devices, such as standards for the display of cumulative time that an X-ray system is activated. FDA has also developed guidance for state and local agencies to aid in emergency response planning for accidental or terrorism-related radioactive contamination of human food and animal feeds. Other federal agencies also have roles in radiation protection. For example, ionizing radiation is addressed in specific OSHA standards for general industry, shipyard employment, and construction. According to DOD officials, DOD operates facilities and engages in activities where radiation exposure can occur and implements occupational and public dose limits established by NRC and states in which these facilities and activities are located. NASA sets radiation exposure limits for space flight and supports research on the health effects of cosmic radiation to better manage health risks to astronauts. DHS’s Federal Emergency Management Agency provides guidance on responding to incidents involving release of radioactive material and has established procedures for review and approval of state and local emergency plans for the offsite effects of a radiological emergency that may occur at a commercial nuclear power facility. Two U.S. scientific advisory bodies—the National Academies’ Nuclear and Radiation Studies Board and the National Council on Radiation Protection and Measurements (NCRP)—and one international body—the International Commission on Radiological Protection (ICRP)—are involved in analyzing scientific developments regarding the health effects of radiation exposure and advising federal agencies. The National Academies’ Nuclear and Radiation Studies Board conducts studies on safety and other issues associated with nuclear and radiation-based technologies. The board has published a series of seven reports to advise the U.S. government on the relationship between exposure to radiation and human health, with the most recent report published in 2006. NCRP, a congressionally-chartered, nonprofit educational and scientific body, seeks to formulate and disseminate information, guidance, and recommendations on radiation protection and measurements that represent the consensus of leading scientific thinking. NCRP issues reports on specific issues of concern to federal agencies, such as on the use of medical equipment that produces radiation. ICRP, an independent, international organization with members consisting of scientists and policymakers in the field of radiological protection, offers recommendations to regulatory and advisory agencies on protection against radiation. In addition to addressing particular areas within radiological protection, its publications describe an overall system of radiological protection. Several other organizations are involved in scientific research and standards setting for protection against radiation. For example, the United Nations Scientific Committee on the Effects of Atomic Radiation (UNSCEAR), which includes 27 United Nations states as members of its scientific committee, has a mandate to assess and report on levels and effects of exposure to radiation. Its summaries of basic scientific studies, along with scientific developments reported by the National Academies and other national organizations, serve as a primary source of information for NCRP and ICRP. The International Atomic Energy Agency, in collaboration with other organizations, has issued basic safety standards for protecting people and the environment from harmful effects of radiation. It has also issued safety requirements for preparedness and response for a nuclear or radiological emergency. The World Health Organization, one of the organizations that has collaborated with the International Atomic Energy Agency, also supports research on the health effects of radiation. EPA, NRC, DOE, and FDA have generally used the advice of scientific advisory bodies to develop and apply radiation protection requirements and guidance for workers and the public for the four radiation settings in our review. Three scientific advisory bodies—ICRP, NCRP, and the National Academies’ Nuclear and Radiation Studies Board—have supported the use of the linear no-threshold model for such requirements and guidance; this model assumes that the risk of cancer increases with every incremental increase in radiation exposure. The requirements and guidance the four agencies have developed and applied vary depending on the settings, in part because the scientific advisory bodies on which the agencies relied have also developed recommendations specific to the settings we reviewed. In developing and applying radiation protection requirements and guidance for workers and the public—specifically, developing limits on dose or increased health risk and guidance levels on exposure—EPA, NRC, DOE, and FDA have generally taken the advice of scientific advisory bodies. This advice includes the use of the “linear no-threshold model,” which assumes that the risk of cancer increases with every incremental increase in radiation exposure. The model is used to estimate the risk of cancer when the overall level of exposure is in the range considered to be low dose. At this level of exposure, data from epidemiological studies of individuals exposed to radiation provide evidence of increased risk to cancer, but with uncertainties about the extent of this risk. Under this model, federal regulations set dose limits for radiation exposure that are below the level in the National Academies’ 2006 report on radiation and human health for defining low-dose radiation. For example, NRC’s annual dose limit for members of the public (excluding natural, or background, sources of radiation) is 1 mSv (0.1 rem), or a hundredth of the level the National Academies considers low dose. Three key scientific advisory bodies—ICRP, NCRP, and the National Academies’ Nuclear and Radiation Studies Board—have supported use of this model for development of radiation protection requirements and guidance. For example: ICRP, in its 2007 update to its recommendations on radiological protection, stated that at low doses of radiation, it considers the linear no-threshold model to be the best practical approach to managing risk from radiation exposure. In addition, ICRP stated that this model is consistent with the principle that actions should be taken to avoid or diminish harm to human life or health that is scientifically plausible but uncertain, as is the case at low doses of radiation. ICRP’s update also explained that it periodically re-evaluates its recommended dose limits based on its evaluation of new scientific data and information. NCRP, in a 2001 study on the linear no-threshold model that it continues to reference today, noted that the existing epidemiological data on the effects of low-dose radiation are inconclusive and, in some cases, contradictory, prompting some observers to dispute the validity of the linear no-threshold model. Nevertheless, NCRP concluded that while there is uncertainty about the health effects of low-dose radiation, the linear no-threshold model is more plausible than other models, such as the hormesis model, which assumes that low-dose radiation protects against rather than increases the risk of cancer. Further, according to NCRP’s president, recent epidemiological studies indicate that the preponderance of evidence continues to support the linear no-threshold model for use in radiation protection. The National Academies, in its 2006 report on low-dose radiation, supported the use of the linear no-threshold model, stating that the balance of evidence from epidemiologic, animal, and mechanistic studies tends to favor a simple proportionate relationship at low doses between radiation dose and cancer risk. According to the National Academies, the availability of new and more extensive data since the publication of its previous report in 1990 strengthened confidence in the 2006 report’s estimates of cancer risk. For example, the 2006 report incorporated data from an additional 15 years of follow-up of Japanese atomic bomb survivors and from studies of nuclear workers exposed to low-dose radiation. Nevertheless, these advisory bodies have recognized challenges in accurately estimating cancer risks from very low doses of radiation exposure when using the linear no-threshold model. For example, the epidemiological data used to estimate the dose-risk relationship for American workers over a 1-year period are largely from studies of Japanese atomic bomb survivors’ exposure to radiation from the atomic bomb. As a result, to account for different doses and dose rates of radiation exposure, advisory bodies have recommended that estimates of the risk of low doses using these data be adjusted accordingly. For example, in radiation protection guidance issued in 2007, ICRP recommended that cancer risk estimates for low doses of radiation be adjusted downward by a factor of one-half. Figure 1 depicts examples of the dose limits and guidance levels established by EPA, NRC, and DOE. (See app. I for further examples.) As shown in the figure, the public dose limit for nuclear power plants is one-third the U.S. average natural background radiation level. Some stakeholders have questioned whether radiation dose limits based on the linear no-threshold model are too strict, or whether they are strict enough, and have advocated for revising dose limits and guidance levels. For example, in 2015, NRC received three petitions from different individuals proposing that NRC raise its occupational and public dose limits. One petitioner commented that some studies suggest low levels of radiation have protective effects and that the costs of complying with linear no-threshold-based regulations were high. Similarly, a joint study by the French National Academies of Science and of Medicine in 2005 concluded that epidemiological studies have been unable to find a significant increase of cancer at low levels of radiation exposure. Conversely, representatives we interviewed from two nonprofit groups, Physicians for Social Responsibility and Beyond Nuclear, told us that dose limits based on the linear no-threshold model were not strict enough to protect vulnerable groups, such as children and pregnant women and their fetuses. NRC officials told us that in the absence of convincing evidence that there is a dose threshold below which low levels of radiation are beneficial or not harmful, NRC will continue to follow the recommendations of scientific advisory bodies to use the linear no-threshold model. Similarly, officials from EPA told us that they would consider changing the use of the linear no-threshold model as the basis of their requirements and guidance only if there were a strong recommendation from scientific advisory bodies on radiation protection as well as an endorsement of the change by the National Academies. In addition, EPA published a paper in 2009 that stated that it believed that the evidence on health effects of radiation exposure does not preclude the possibility of a threshold below which there is no increased risk of cancer, but that the evidence at present does not support the existence of a threshold. The limits and guidance the four agencies have developed and applied vary depending on the settings in which exposure can occur, as described below. This result is in part because the scientific advisory bodies on which the agencies relied have developed recommendations specific to the four settings we reviewed: (1) operation and decommissioning of nuclear plants; (2) cleanup of sites with radiological contamination; (3) use of medical imaging equipment that produces radiation; and (4) accidental or terrorism-related exposure to radiation. According to NRC’s notice of its final rule for standards for protection against radiation, NRC used ICRP’s recommendations issued in 1977 as the basis for NRC’s regulations. ICRP stated that it developed its 1977 recommendations on occupational dose limits in part through a comparison between the cancer risk from occupational exposure to radiation and the rates of occupational fatalities in industries recognized as having high standards of safety. Thus, nuclear power plant workers would not face a greater risk of cancer than the fatality risks, whether due to accidents or disease, that workers face in other industries. For the general public, ICRP suggested that the cancer risk—and therefore the dose limit—should be less than that for workers and should be comparable to the public’s risk from everyday activities, such as taking public transportation. ICRP further stated that when setting public dose limits, an agency must consider members of the public belonging to critical groups, such as children and pregnant women, who may be more susceptible to the effects of radiation than the population as a whole. According to one of ICRP’s key recommendations for radiation protection, radiation exposure should be limited to keep the likelihood and magnitude of exposure as low as reasonably achievable, taking into account economic and societal factors. In keeping with this recommendation, NRC requires nuclear power plants to have a radiation protection program that includes measures to keep doses as low as reasonably achievable (ALARA). NRC defines ALARA to mean making every reasonable effort to maintain exposures to radiation as far below dose limits as is practical consistent with, among other things, the economics of improvements in relation to benefits to the public health and safety. Under the ALARA principle, NRC encourages nuclear plants to demonstrate their use of the principle through cost-benefit analyses or other quantifiable methods. According to NRC officials, nuclear power plants typically set their own occupational dose limits at 40 percent of NRC’s regulatory limit of 50 mSv (5 rem) per year, and cost is generally a key criterion that plants use to determine what actions to take to reduce radiation exposures under their ALARA programs. At the nuclear power plant we visited, representatives told us that under their ALARA plan, the plant set its own dose limits for workers at 40 percent of the regulatory limit. Officials at the plant told us that they have been able to keep exposures below the plant’s own limit by continuously seeking opportunities to reduce unnecessary worker exposure to radiation, such as using robots to perform maintenance work in radiation areas. According to NRC’s 2014 annual report on occupational radiation exposure, none of the 124,831 nuclear power plant workers who were monitored in 2014 received a dose above NRC’s regulatory limit, and over 99 percent of these workers received a dose below the 40-percent level used by many plants as their own limit. DOE and EPA both used the recommendations of scientific advisory bodies, including the use of the linear no-threshold model, to develop limits on dose or increased health risk for members of the public from sites with radiological contamination, even though the agencies used different approaches in implementing the recommendations. For example, in an order on radiation protection of the public and environment, DOE set a public dose limit of 1.0 mSv (0.1 rem) per year, which was the dose limit recommended by ICRP in 1990. In developing its recommendations, ICRP used the assumptions of the linear no-threshold model to identify a dose that would not cause more than a small increase in the age-specific mortality rate from cancer. In contrast, according to a 2014 EPA memorandum on cleanup of sites with radiological contamination, EPA uses a risk-based approach to prescribe cleanup levels for carcinogens, including radiation, in a range that will not result in more than 1 in 10,000 to 1 in 1 million additional cancers in a population during their lifetimes. Under this approach, EPA uses the assumption of the linear no-threshold model to set site-specific levels of cleanup that account for various factors, such as the site’s expected future land use and the presence of other contaminants, such as chemicals that may also increase the risk of cancer. Under its 2014 memorandum, EPA determined that when using a federal or state standard for radiation protection at sites with radiological contamination, this standard is generally not sufficiently protective if it is greater than 0.12 mSv (0.012 rem) per year. According to FDA officials, FDA does not have the authority to regulate the total amount of radiation exposure a patient receives from medical imaging equipment. They also commented that decisions such as the frequency of taking medical images are based on patient need and that those decisions determine the total amount of radiation exposure to the patient. Similarly, ICRP’s 2007 guidance on radiation protection states that, while all use of radiation in medicine should be justified and the radiation dose from each examination should be as low as reasonably achievable, radiation dose limits do not apply to medical exposures of patients. FDA officials stated that, instead of setting limits on total amount of radiation exposure to patients, the agency regulates the maximum limits radiation output of medical equipment. In particular, they stated that the agency based its equipment standards on NCRP guidance from 1968 on medical X-ray and gamma ray protection. They also commented that this NCRP guidance provided a dose rate limit for the equipment and stated that the exposure rate should be as low as reasonably achievable. In a 2005 Federal Register notice on FDA’s change to its performance standards for medical-imaging equipment, FDA stated that it used the assumptions of the linear no-threshold model to determine that the health benefits to medical staff and patients (in monetary terms) exceeded the costs incurred by equipment manufacturers and FDA to implement the change. In keeping with the principle that radiation exposure should be kept as low as reasonably achievable, FDA encourages voluntary measures by health care providers to address radiation exposure to patients from the use of medical-imaging equipment. Under an initiative launched in 2010, FDA identified a number of factors that contribute to levels of exposure that exceed the levels for meeting patients’ clinical need, and FDA identified steps to mitigate these factors. For example, its initiative recommended that healthcare professional organizations continue to develop nationally recognized benchmark levels for medical-imaging procedures that use radiation, and FDA stated that it has increased its participation in these efforts both on its own and through collaborative efforts with industry and healthcare professional organizations. Benchmark levels are not mandatory but allow medical facilities to investigate when a medical examination exceeds the benchmark and determine whether it is possible to reduce exposure without adversely affecting image quality. To develop guidance for state and local governments’ emergency response to deliberate or accidental radiological incidents, EPA and FDA used the recommendations of scientific advisory bodies, including the assumptions of the linear no-threshold model to recommend radiation doses at which protective actions would provide a net benefit when compared with other factors, such as cost of the actions taken. For example, according to its 2016 guidance on emergency response to radiological incidents, EPA compared the cost of evacuation under several scenarios with the number of cancer deaths avoided to recommend a radiation dose to the public at which evacuation should be considered. Using ICRP guidance, EPA assumed a linear relationship between radiation exposure and cancer risk—a principle of the linear no- threshold model—to calculate the number of potential cancer deaths. According to EPA’s guidance, the radiation dose the agency identified fell within the risk level it considered acceptable, while also meeting EPA’s criteria that the cost of the protective action be justified by the reduction of risk to public health. According to EPA’s guidance, decisions on the radiation doses at which to take protective actions need to consider health risks other than radiation. For example, weather hazards may impede evacuation and favor sheltering-in-place instead. Similarly, EPA’s guidance explains that decisions on relocation need to account for a variety of health problems that relocation itself can cause. In its response to frequently asked questions about radiation in Fukushima, Japan, the World Health Organization noted that these problems were evident in the aftermath of the March 11, 2011, earthquake and subsequent tsunami that caused significant damage to the Fukushima Daiichi Nuclear Power Station, releasing radioactive material into the environment. There were no known acute deaths or illnesses from radiation exposure, but the relocation of thousands of people caused an increase in disaster-related deaths, as well as mental health and access to health care issues, according to the World Health Organization. FDA also relied on ICRP guidance and the linear no-threshold model to recommend radiation doses at which protective actions would provide a net benefit when compared with other factors. In particular, according to a 1998 Federal Register notice about recommendations for accidental radioactive contamination of human food and animal feed, the agency developed protective action guides for state and local agencies responding to these types of accidents. These guides provide a recommended radiation dose range in which countermeasures should be taken for the contaminated food and feed after an accident. This range is based on values set by ICRP on the basis of the linear no-threshold model. For fiscal years 2012 through 2016, seven federal agencies—CDC, DOD, DOE, EPA, NASA, NIH, and NRC—obligated about $210 million for research on the health effects of low-dose radiation, but annual funding decreased by 48 percent. During the period we reviewed, the seven federal agencies that funded this research collaborated on particular projects, but they did not use a collaborative mechanism to address overall research priorities, such as research needs that advisory bodies identified regarding health effects of low-dose radiation. From fiscal year 2012 through fiscal year 2016, seven federal agencies obligated $209.6 million for research on the health effects of low-dose radiation. As shown in figure 2, DOE and NIH accounted for most of this funding, with DOE obligating $116.3 million and NIH obligating $88.6 million, or about 56 percent and 42 percent of the total, respectively. The five other agencies—NRC, NASA, DOD, EPA, and CDC—obligated the remaining $4.7 million. The research that the seven federal agencies funded included both epidemiological and radiobiological studies. Agency officials told us that both types of research are important to better understand the health effects of low-dose radiation and could inform future efforts to update dose limits and guidance levels for radiation exposure. Two of the largest epidemiological studies funded by federal agencies were the Epidemiologic Study of One Million U.S. Radiation Workers and Veterans (Million Person Study)—an ongoing study headed by NCRP— and the International Nuclear Workers Study, a multi-year study that includes over 300,000 workers from France and the United Kingdom as well as from the United States. The Million Person Study began in 2009 and includes plans to examine mortality statistics on multiple cohorts (populations) of over 1-million U.S. radiation workers, veterans, and other individuals. The purpose is to provide information about low-dose radiation health risks when the exposures are received gradually over time and not instantaneously, as was the case for the 1945 atomic-bomb exposures in Japan. Officials from two agencies that fund or use the results of research on the health effects of low-dose radiation—DOE and NRC—told us that NCRP’s Million Person Study can help address these research gaps. For example, according to NRC, the study is important research in order for the agency to examine the radiation risks to workers exposed to doses and dose rates in actual exposure settings. DOE, EPA, NASA, and NRC have provided funding for the Million Person Study. DOE’s Office of Science provided the initial funding of $500,000 for the pilot study in fiscal year 2009, as well as $869,000 for a subsequent larger study, as part of its Low-Dose Radiation Research Program, but DOE stopped funding the study in fiscal year 2010 to fund other research priorities. Since DOE’s initial $500,000 funding for the pilot study, NCRP has received a total of $4.2 million in additional funding from DOE, EPA, NASA, and NRC, according to DOE officials. In addition, an explanatory statement accompanying the fiscal year 2017 Consolidated Appropriations Act directed DOE to provide not less than $500,000 from funds for DOE’s Office of Environment, Health, Safety and Security for this study. With the funding it has received, NCRP completed various feasibility studies and follow-up work on several of the different cohorts of individuals included in the overall study. For example, NCRP began work on a mortality study of nuclear power plant workers. NCRP has estimated that it would need $20 million to analyze and report on of all of the cohorts included in the overall study. In addition, NCRP’s president told us that continuous funding could help to retain the study’s original investigators, who might otherwise move onto other work. DOE also provided about $2.1 million for the International Nuclear Workers Study for fiscal years 2012 through 2016, and CDC provided $66,000. According to CDC officials, the workers in the study experienced a similar form of radiation, thereby simplifying the study’s analysis, and the results of the study have shown associations between radiation exposure and leukemia and solid cancers. Additional information on the types of low-dose radiation research funded by federal agencies and the results of this research is described below: DOE has two offices that have funded research on the health effects of low-dose radiation—the Office of Science and the Office of Environment, Health, Safety and Security—according to funding information DOE provided. The Office of Science established the Low Dose Radiation Research Program in 1998 and funded it through fiscal year 2016. A primary focus of this program was to fund radiobiological research, and over the course of the program, it provided an average of about $14 million per year for such research, which included funding for the Million Person Study. According to DOE’s website for the program, the program provided data and information about the low-dose range of exposure, producing 737 peer-reviewed publications as of March 2012. According to a 2016 report from DOE’s Biological and Environmental Research Advisory Committee, among the important discoveries under the program was a phenomenon known as the bystander effect, where cells may sustain radiation damage even though no radiation passes through them. Other areas of discovery included the role of DNA repair and the immune system, as well as the potential beneficial effects at the cellular level caused by low-dose radiation. The Office of Environment, Health, Safety and Security provided annual funding from fiscal year 2012 through fiscal year 2016 for epidemiological studies in two areas: (1) the Radiation Effects Research Foundation, which conducts studies involving Japanese atomic bomb survivors in Hiroshima and Nagasaki and is a source of data used by national and international standard-setting organizations and scientific advisory bodies to set regulations and (2) assessments of worker and public health risks from radiation exposure resulting from nuclear weapons production activities in the former Soviet Union, which provided DOE researchers with data from Russian workers who experienced chronic exposure to radiation. NIH has funded and conducted both epidemiological and radiobiological studies on low-dose radiation, according to NIH officials. The officials stated that the studies are conducted through the National Cancer Institute’s internal research program for radiation epidemiology, as well as through NIH’s research programs for external funding of investigator-initiated research. The aim of the internal research program for radiation epidemiology is to identify, understand, and quantify the risk of cancer in populations exposed to various types of radiation, and to advance understanding of cancer caused by radiation. Other institutes of NIH, including the National Institute of Environmental Health Sciences, also fund research related to the health effects of radiation exposure as part of NIH’s overall mission to fund medical research. Examples of research supported by NIH have included (1) a study conducted in partnership with the U.S. Department of Veterans Affairs on cancer mortality among military participants in U.S. nuclear weapons tests and (2) a tissue bank with samples from Chernobyl survivors. These samples are being used to understand the effects of radioactive exposure from nuclear power plant accidents. NIH has also funded radiobiological research on high- dose radiation, and some of this research also applies to low-dose radiation. EPA helps fund research through an ongoing interagency agreement with DOE’s Oak Ridge National Laboratory, according to EPA officials. The funding supports the development of models that provide information about doses to particular organs from ingestion or inhalation of a specific quantity of a radioactive element, such as cesium or plutonium. According to EPA instructions for calculating radiation dose and risk, EPA uses this information to estimate cancer risks of exposure to over 800 radioactive elements. These estimates, according to EPA, can be used by federal and state agencies to develop and implement radiation protection regulations and standards. EPA also provided funding for the Million Person Study. According to EPA officials, the agency contributed to the study to be able to discuss and review the research in its early stages. NRC officials we interviewed said that NRC does not generally fund research on radiation’s health effects but agreed to provide funding to the Million Person Study with the understanding that NRC would be a minority funding partner in the program. However, after DOE stopped funding the study, NRC became the largest contributor, providing a total of $2.1 million in fiscal years 2012 to 2016. NRC also funded an epidemiological study analyzing cancer risks in populations living near U.S. nuclear facilities, but it did not continue the study because of the study’s limited usefulness for drawing conclusions about risk and its long duration and high cost, according to NRC officials. NASA officials told us that the agency mostly conducts research on space-based radiation, which differs from ground-based radiation in terms of its physical characteristics and its effects on health. In the past 5 years, NASA has funded over $100 million for research on space-based radiation, including research on its health effects, such as on the risk of acute central nervous system effects. The agency also provided funding for low-dose radiation research at DOE, as well as for the Million Person Study. CDC has provided some funding for epidemiological studies such as those evaluating the long-term effects of occupational radiation exposures or analyzing mortality among nuclear workers, according to funding information provided by CDC. For example, according to this information, CDC partially funded the International Nuclear Workers Study. CDC officials told us that the program has published more than two dozen studies related to occupational exposures and cancer risks among workers across the DOE complex. CDC’s National Institute for Occupational Safety and Health also provided funding for institute researchers to conduct studies on flight attendants exposed to cosmic radiation and on uranium miners exposed to radon. DOD has contributed a small amount of funding for radiation health effects research activities through the Armed Forces Radiobiology Research Institute, according to funding information provided by DOD. Most of the work conducted through the institute is research on radiation countermeasures—treatments that could be used in the aftermath of an attack involving the release of radioactive material. In addition, according to DOD’s funding information, the institute provides some funding to researchers in order to better understand, for example, cancer risks due to low-dose radiation exposure. As shown in figure 3, in fiscal years 2012 through 2016, the seven agencies collectively decreased their annual funding obligations for research on health effects of low-dose radiation by 48 percent, from $57.9 million in fiscal year 2012 to $30.4 million in fiscal year 2016, and NIH and DOE decreased their annual funding obligations by 48 and 45 percent, respectively. DOE accounted for a large portion of this overall decrease in annual funding. Specifically, over this 5-year period, DOE reduced its annual funding obligations for this area of research by 45 percent—from $32.6 million in fiscal year 2012 to $18.0 million in fiscal year 2016. According to DOE, the decrease was primarily due to DOE’s reduction in funding for its Low Dose Radiation Research Program. DOE’s Office of Science established this program in 1998 to fund research on the effects of radiation on genomes, cells, and living organisms, with the aim of providing a scientific basis for developing radiation protection standards in line with the research results that demonstrate the response of complex biological systems to low doses of radiation. According to DOE officials, decreases in funding for the program reflected a shift toward bioenergy and environmental research within the department’s Office of Science. These officials said that the agency provided the final funding for the program in fiscal year 2016. In contrast, funding remained stable for research supported by DOE’s Office of Environment, Health, Safety and Security on epidemiological studies in Japan and Russia. Similarly, over the 5-year period, NIH’s funding for low-dose radiation research decreased by 48 percent—from $23.1 million in fiscal year 2012 to $12.0 million in fiscal year 2016. NIH officials commented that sequestration occurred during the time period in which radiation research funding decreased. In addition, NIH officials explained that funding levels for a particular disease or research area can fluctuate depending on several factors, including the number and quality of research proposals submitted and the outcome of NIH’s peer reviews of the proposals, as well as the overall research budget. Table 1 shows agencies’ annual obligations for research on health effects of low-dose radiation. The seven agencies that funded research on health effects of low-dose radiation for fiscal years 2012 through 2016 collaborated on particular research projects through the use of several mechanisms, including the following: Joint funding of individual research projects: For example, as previously mentioned, DOE’s Office of Science, EPA, NASA, and NRC jointly funded the Million Person Study, and CDC and DOE’s Office of Environment, Health, Safety and Security helped fund the International Nuclear Workers Study. Participation in interagency committees: For example, DOD, DOE, EPA, HHS and NRC are members of the Interagency Steering Committee on Radiation Standards, which has a goal of promoting consistency in federal radiation protection programs. Collaborating on research on low-dose radiation is not a committee focus, but the committee provides a forum for sharing information on research developments. Similarly, the head of DOE’s Office of Environment, Health, Safety and Security co-chairs a bilateral U.S.-Russian Federation committee for coordinating research on the health effects of exposure to radiation in the Russian Federation from the production of nuclear weapons. CDC, DOD, EPA, NASA, and NRC are also U.S. members of the committee. Participation in meetings and conferences: For example, in June 2017, DOE’s Oak Ridge National Laboratory hosted a workshop on radiation-protection research needs. The workshop agenda included presentations by DOE, EPA, NRC, FDA, and NIH’s National Cancer Institute. In addition, DOE officials told us they share research results informally with other agencies through their participation in conferences held by NCRP and other groups, and NIH officials also said that members of the radiation epidemiology scientific community have the opportunity to connect at specialized meetings. However, the seven agencies that fund research on health effects of low- dose radiation did not use a collaborative mechanism to address overall research priorities, such as research needs that scientific advisory bodies have identified. The 2006 National Academies report to advise the U.S. government on the relationship between exposure to radiation and human health—which was funded in part by DOD, DOE, EPA and NRC— identified 12 areas of research needs. Many of these areas were related to uncertainties from the linear no-threshold model and, by extension, in the agencies’ dose limits and guidance levels that are based in part on that model. In addition, as previously noted, the 2016 report of DOE’s Biological and Environmental Research Advisory Committee also provided information about research needs in low-dose radiation and found that further research could decrease uncertainty in predicting cancer risk from low-dose radiation. The report recommended that, should DOE decide to continue research in this area, workshops be convened to formulate a specific research program. In addition, the report stated that other agencies—including NRC, NIH, EPA, DOD, and NASA—could benefit from the reduction in uncertainty that could be obtained by this research. Until recently, DOE’s Low Dose Radiation Research Program provided a stable source of funding for such research and according to DOE’s website, DOE took a leading role in advocating for greater communication and coordination between the fields of radiation biology and epidemiology. As previously mentioned, DOE is the federal agency that currently has primary responsibility under the Atomic Energy Act of 1954 for research related to the protection of health during activities that can result in exposure to radiation. DOE’s decisions to reduce funding the program in fiscal year 2012 and stop funding the program in fiscal year 2016 also reduced the role that DOE previously held as a leading source of federal funding for low-dose radiation research. DOE’s reduced role has created a void in federal efforts to maintain a collaborative mechanism for low-dose radiation research, and no other agency has stepped forward to fill this void. Our previous work has shown that collaborative mechanisms can serve multiple purposes, such as leading interagency efforts to develop and coordinate sound science and technology policies across the federal government. Although collaborative mechanisms differ in complexity and scope, they all benefit from certain key features, such as leadership, which raise issues to consider when implementing these mechanisms. Such issues include: whether a lead agency or individual has been identified; if leadership is shared, whether the agencies have clearly defined roles and responsibilities; and how leadership will be sustained over the long-term. For example, the Interagency Steering Committee on Radiation Standards includes a process for rotating the leadership role among member agencies. DOE is well positioned to lead an effort to ensure that federal agencies have a mechanism for interagency collaboration to address overall research priorities related to low-dose radiation health effects because of the agency’s past experience as a leader in this area of research. Such a role is also consistent with DOE’s research responsibility under the Atomic Energy Act of 1954. Such an effort could help DOE and the collaborating agencies determine roles and responsibilities, including leadership, when addressing shared research priorities. DOE and other federal agencies have invested millions of dollars in low- dose radiation research, and this research has led to a better understanding of the health effects of radiation exposure, thereby helping federal agencies develop and implement radiation protection requirements and guidance for workers and the public. DOE has provided more than half of all federal funding for this research over the past several years. Given the reduction in funding for low-dose radiation research, federal agencies can benefit from greater collaboration on addressing their research priorities in this area. Our previous work has shown that collaborative mechanisms can be used for coordinating federal science efforts and that agencies can enhance their collaborative efforts through key practices, such as agreeing on leadership roles and responsibilities. In the past, DOE took a leading role in both funding and evaluating low- dose radiation research, and the agency continues to fund a substantial portion of the research. However, more recently DOE’s funding has significantly decreased, resulting in a lack of leadership in this area. DOE, consistent with its past experience as a leader in this area of research and its research responsibility under the Atomic Energy Act of 1954, could assist agencies in developing an interagency collaborative mechanism for the future. We recommend that the Secretary of Energy lead the development of a mechanism for interagency collaboration to determine roles and responsibilities for addressing priorities related to research on the health effects of low-dose radiation. We provided a draft of this report to the Department of Commerce; DHS; DOD; DOE; Department of Labor; EPA; HHS’s CDC, FDA, and NIH; NASA; and NRC for review and comment. DOE, the Department of Labor, EPA, HHS, and NRC provided technical comments, which we incorporated as appropriate. DOE also provided written comments, which are reproduced in appendix II. The other agencies did not provide any comments. DOE commented that in general, the draft report reflects how federal agencies, including DOE, developed and applied radiation protection requirements and guidance for workers and the public. DOE did not concur with our recommendation that it lead the development of a mechanism for interagency collaboration on research on the health effects of low-dose radiation. In particular, DOE stated that EPA and NRC also have legal mandates to research low-dose radiation exposure and that these agencies establish their research priorities in accordance with their respective budget authorities and recommendations from independent advisory bodies. DOE stated that as a result, it would not be appropriate for DOE to lead the development of a mechanism for interagency collaboration. Instead, according to DOE, from its experience, the leadership of an organization with government-wide responsibilities would result in the most effective interagency collaboration. We believe that DOE’s concerns stem from a misinterpretation of our recommendation, and we made several changes to our report and our recommendation to clarify DOE’s role. In particular, we did not recommend that a mechanism for interagency collaboration serve as a replacement for agencies’ legal mandates, budget authorities, and recommendations from independent advisory bodies. Instead, this mechanism would help agencies address shared research priorities, such as research needs that the National Academies, in advising the U.S. government, identified regarding health effects of low-dose radiation. According to officials we spoke with from DOE’s Office of Environment, Health, Safety and Security, more collaboration among agencies on low- dose radiation research would be very helpful. In making our recommendation, we did not specify the coordinating mechanism that agencies should use and instead left it to DOE to lead the development of an appropriate mechanism. If the leadership of an organization with government-wide responsibilities would result in more effective interagency collaboration, as DOE suggested in its written comments, then DOE could implement our recommendation by working with such an organization to obtain its involvement in a coordination mechanism. We continue to believe that an interagency coordination mechanism for low-dose research is needed and that DOE is in the best position to lead agencies in developing the most appropriate mechanism. As agreed with your offices, 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 to the appropriate congressional committees, the Secretary of Commerce, the Secretary of Defense, the Secretary of Energy, the Secretary of Health and Human Services, the Secretary of Homeland Security, the Secretary of Labor, the Administrator of EPA, the Administrator of NASA, the Chairman of NRC, and other interested parties. In addition, the report will be available at no charge on the GAO website at http://www.gao.gov. If you or your staff members have any questions about this report, please contact John Neumann at (202) 512-3841 or neumannj@gao.gov. Contact points for our Offices of Congressional Relations and Public Affairs may be found on the last page of this report. GAO staff who made key contributions to this report are listed in appendix III. To prevent cancer and other harmful effects associated with exposure to radiation, federal agencies have established radiation protection measures that apply to a wide range of settings in which exposure can occur. These measures call for radiation exposure, for workers and for the public, to be kept within regulatory limits (either on dose or increased health risk) or, for emergency situations, non-binding guidance on exposure levels established for protecting individuals. Table 2 shows examples of federal agencies’ dose limits, guidance levels, and other radiation protection measures. John Neumann, (202) 512-3841 or neumannj@gao.gov. In addition to the individual above, Joseph Cook (Assistant Director), Allen Chan, Kendall Childers, Richard Frankel, Richard Johnson, David Messman, Cynthia Norris, Josie Ostrander, Todd Paulsen, Amber Sinclair, Sara Sullivan, and Jack Wang made key contributions to this report.

Summary: According to EPA, exposure to low doses of radiation does not cause immediate health effects but may increase a person's cancer risk. Federal agencies fund research on cancer risk, but uncertainties remain about risk assessments that federal agencies use to develop radiation protection regulations and guidance. GAO was asked to examine federal agencies' radiation protection requirements and guidance and related research. This report (1) describes how selected federal agencies have developed and applied radiation protection requirements and guidance and (2) examines the extent to which federal agencies have funded and collaborated on research on low-dose radiation's health effects for fiscal years 2012 to 2016. GAO selected four federal agencies, based on their development of requirements or guidance for settings in which radiation exposure to workers and the public can occur. GAO reviewed agency documentation and interviewed agency officials on the development of the requirements and guidance. GAO also collected and examined federal-funding data for low-dose radiation research from seven agencies that fund this research. The Department of Energy (DOE), Nuclear Regulatory Commission (NRC), Environmental Protection Agency (EPA), and Food and Drug Administration generally used the advice of scientific advisory bodies to develop and apply radiation protection requirements and guidance for workers and the public in the radiation exposure settings that GAO reviewed. These settings were: (1) the operation and decommissioning of nuclear power plants; (2) the cleanup of sites with radiological contamination; (3) the use of medical equipment that produces radiation; and (4) accidental or terrorism-related exposure to radiation. Specifically, the agencies relied on the advice of three scientific advisory bodies that supported the use of a model that assumes the risk of cancer increases with every incremental radiation exposure. Accordingly, the agencies have set regulatory dose limits and issued guidance to confine exposure to levels that reduce the risk of cancer, while recognizing that scientific uncertainties occur in estimating cancer risks from low-dose radiation. For example, NRC requires nuclear power plants to consider measures for limiting workers' exposure below NRC's regulatory dose limit, such as by using robots for maintenance work in radiation areas. GAO identified seven federal agencies that funded research on low-dose radiation's health effects. In fiscal years 2012 to 2016, DOE, NRC, EPA, and four other federal agencies obligated about $210 million for such research (see table). Although the agencies have collaborated on individual projects on radiation's health effects, they have not established a collaborative mechanism to set research priorities. GAO's previous work has shown that federal agencies can use such mechanisms to implement interagency collaboration to develop and coordinate sound science policies. In the past, DOE took a leading role in this area because DOE provided stable funding and advocated for greater coordination on research on low-dose radiation's health effects. However, since fiscal year 2012, DOE has phased out funding for one of its main research programs in this area. This has created a void in coordination efforts among federal agencies, and no other agency has stepped forward to fill this void. Because of DOE's prior experience as a leader in this area of research and its research responsibility under the Atomic Energy Act of 1954, it could play an important role in helping federal agencies establish a coordinating mechanism for low-dose radiation research. Dollars are in millions and have not been adjusted for inflation Source: GAO analysis of agency data. | GAO-17-546 GAO recommends DOE lead development of a mechanism for interagency collaboration on research on low-dose radiation's health effects. DOE disagreed, stating that agencies set their own research priorities. GAO continues to believe that DOE is in the best position to lead such an effort, as discussed in the report.