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- Health The production of nuclear weapons involves activities and materials that can affect human health adversely. Some of the hazards differ little from those encountered in other industrial settings, and Hey are addressed by the usual practices of industrial safety and hygiene. Others, such as exposure to radiation and the use of certain hazardous materials, are unique to the weapons complex. Both workers and the public are potentially affected. Occupational health programs are instituted to protect workers, while environmental controls are established to protect public health. The principles of occupational health management apply to both chemical and radiation hazards. Exposure to radiation can have a variety of effects on human health. Effects range from degenerative illness or death to cancers, developmental abnormalities, and possibly, genetic changes. These effects can occur at both high and lower levels of exposure. The seventy of effects generally decreases with decreasing dose. Based on extrapolation from animal studies, the effects of gamma or x-ray radiation decrease as the dose is delivered over a longer period of time. Studies of atomic bomb survivors and persons exposed to therapeutic or diagnostic radiation provide information on effects on health that result from higher levels of exposure. However, there is not sufficient information to confimn the methods used for extrapolating from these data to the much lower levels of exposure that normally arise in the occupational setting. Studies of animals are limited by the extent to which quantitative extrapolations to humans can be made, and even these studies are not unambiguous. We are not aware of any widespread occurrences of occupational diseases in the nuclear weapons complex arising from failure to comply with recognized and 71
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72 TlIE NUCLEAR WEiAPONS COMPLY acceptable work practices. When sporadic occurrences have arisen, the causes were, for the most part, readily identifiable. Some cases of disease caused by accidental exposure to high levels of radiation or to other hazardous substances, such as beryllium, have occurred in the past, but current procedures have been improved to minimize these exposures. However, we believe there is a recognized tendency to reduce vigilance when, over an extended period of time, no obvious or immediate adverse effects arise. We are concerned that there is a notable absence of aggressiveness at most facilities in addressing the possible, although as yet unidentified, effects on health from long-term, low-level occupational exposures. OCCUPATIONAL HEALTH Occupational health or occupational medicine, broadly defined, concerns "all aspects of the relationship between work and health," and it "is to a large degree concerned with the impact of work on the development of medical disorders" (NRC l98Sa). The discipline of occupational health comprises three interrelated kinds of activities: (1) prevention of illness that could occur because of occupational exposures or hazards, (2) diagnosis and treatment of illness in the work force, and (3) monitoring and surveillance of the exposure of workers. Each of these activities is pursued in the weapons complex to varying degrees. Health physics, industrial hygiene, safety, and emergency planning are carried out with the aim of preventing illness and injury. Medical deparunents currently provide clinical therapeutic services and employee assistance programs in the course of diagnosis and treatment. Monitoring and surveillance of workers are carried out under several different auspices, including the health physics, industrial hygiene, and medical departments. The protection of human health is central to each of these efforts. The Role of Medical Expertise Conclusion The centralfocus of programs in health physics, safety, industrial hygiene, emergency planning, and medical programs is the protection of human health; but occupational medical input to decisions is inadequate. In general, the interaction among the health physics, safety, and industrial hygiene professionals seems to be effective. There is, however, negligible occupational medical input to decisions. As best we could determine, the medical departments at the respective weapons facilities become involved with exposures in the workplace only in special cases. For example, at some sites employees working with especially hazardous materials, such as beryllium or lead, are part of a monitoring program that involves the medical department. Similarly, medical
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HEALTH 73 attention is provided to employees with injures or those who have incurred a potentially harmful exposure to radiation or chemicals above established limits. But the medical departments are rarely involved in decisions related to monitoring and controls in the workplace. Often, data on the exposure of employees to radiation or chemicals are stored elsewhere in a facility and become part of an employee's health record only after an inquiry from the medical department. Moreover, medical personnel must often rely on their patients to provide the names of chemicals or other hazards to which they may be exposed in the workplace. In short, medical deparanents are for the most part relegated to a reactive role. The role of the medical department in DOE headquarters appears to mirror those in the contractor facilities. At DOE headquarters, the Office of the Medical Director is located in EH and consists of only four employees: a physician who is the director, a Ph.D., who is assistant director; a program manager, and a secretary. The medical department at headquarters is responsible for administering medical programs and auditing contractor programs. But it is not sufficiently powerful to reshape a program so as to assure more timely and effective medical input. Our review of recent audits indicates that the DOE medical department recognizes the deficiencies identified above, but it has no authority to correct them. Recommendation The occupational health programs at the weapons complex facilities should be improved by encouraging collaboration among the industrial hygiene, health physics, medical program, and other health-related functions at each facility. In particular, medical expertise already available in the facilities should be integrated into the Wily decisionmaking aspects of all occupational health activities. The DOE headquarters medical department should be given sufficient resources to administer, monitor, and elect change in these programs. Chemical Hazards Conclusion While substantial progress has been mode to control exposures to ionizing radiation in the weapons complex, as evidenced by the significant reduction in occupational doses, there appears to be a less than adequate emphasis on hazards associated with exposures to chemicals routinely used in industrial operations. Certain potentially hazardous agents, like beryllium and asbestos, are subject to special control efforts. However, weapons production operations require the routine use of many other chemical agents that present potential hazards to workers, such as cutting oils, organic solvents, and plating solutions. Agents suspected or known to be hazardous require one or more of the following types of control: training, employee monitoring, special handling, or removal of the
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74 THE NUCl~AR WEAPONS COMPLEX worker from He hazard, as in the case of pregnant workers. The degree to which the concerns arising from the use of chemical agents in the workplace are addressed vanes widely among the weapons facilities (see also Chapter 4~. Recommendation Occupational medical programs within the complex should increase the emphasis placed on protection of workers from chemicals suspected to be hazardous at the acute, subacute, or chronic level of exposure. ASSESSING RISKS TO HEALTH In addition to implementing adequate protection programs, it is essential that health procedures be evaluated to determine their effectiveness and identify areas ~ — tor improvement Monitoring in the Workplace Conclusion Collection of health-related data concerning workers in the weapons complex is inadequate with regard to both the lands of data collected and how they are stored. Exposure to high concentrations of hazardous agents characteristically results in manifestations of acute toxicity. Acute exposure also may result in disease after a period of many years. Chronic exposure to chronic toxic agents may result in disease only after the passage of long intervals of time, often even after the cessation of exposure. Because serious effects on health can arise from chronic exposure to hazardous agents at low levels, worker populations should be tracked using a multidisciplinary monitoring and surveillance program. Programs of this type are an integral component of an effective occupational health program; they include periodic medical examinations, industrial hygiene and/or health physics measurements in the workplace, bioassays to measure exposures, and other studies as appropriate. The findings from ongoing monitoring and surveillance programs provide data from which adverse effects resulting from low-level occupational exposures can be identified at the earliest possible time. Such data about workers are useful only to the extent that they are accurate, comprehensive, accessible, and comparable among different populations of workers. Current technology can be used to enter information about the exposure of workers into their medical records automatically. The type of data collected should be standardized within the weapons complex, and it should extend beyond radiation exposures to include toxicants, carcinogens, and reproductive toxicant~s. Data should be stored so as to allow comparisons not only within a given facility but also among facilities. Finally, the data should be accessible to analysis by researchers.
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HEALTH 75 The medical department at DOE headquarters has recognized the need for such an effort and has recently retained an outside contractor to develop a computerized data management package called the Health Track System. The system is intended to provide the capabilities described above, and as designed it has promise. It is not clear, however, how this system will be coordinated with the Secretary's recently proposed Comprehensive Epidemiologic Data Repository (CEDR) (see below). Further, its success will depend on the ability of the DOE headquarters medical deparanent to effect the necessary changes among DOE contractors. Recommendation Monitoring and surveillance programs in the complex should be improved substantially through the use of standardized protocols for data collection, storage, and analysis. In particular, data collected within the complex should be comprehensive, accessible, and comparable. Research on Effects of Exposure to Low Levels of Radiation As a result of the nuclear power plant accidents at Three Mile Island and Chernobyl, public concern regarding the adverse effects of ionizing radiation on human health increased. Included in this increased concern was the health of workers within the weapons complex and that of people living in its vicinity. The Deparunent's record of vagueness and secrecy regarding releases of radioactivity and the extent of environmental contamination contributed significantly to a public lack of confidence in DOE's concern about risks to human health. It has been known since He early 1900s that ionizing radiation is carcinogenic to humans. Current understanding of the health effects of radiation is based on data obtained from studies of survivors of the atomic bombings of Hiroshima and Nagasalci, and of persons receiving radiation for medical purposes. The radiation doses to these populations are relatively high compared to doses due to background radiation) or normal occupational exposure. Estimates of cancer risk at low levels of exposure are obtained from extrapolation from high doses to low doses and depend impotently on the methods used. The latest estimates of risks from external ionizing radiation are given in BEIR V ARC 1990) (the effects of internal emitters are covered in BEIR IV [NRC l988cl). BEIR V provides estimates of low-dose cancer mortality risks based on extrapolation of cancer rates induced from high doses of ionizing radiation. From these values one can compute the risks to hypothetical, highly exposed workers (approximately 10 mSv/yr) or to people exposed to low doses (approximately 0.01 mSv/yr), as shown in Table 5.1. The BEIR V estimates lead to the conclusion that it is barely possible to detect the carcinogenic effects of 10 mSv/yr on an adult ~ Background radiation, excluding radon and medical exposures, is variable but roughly near 1 mSv/yr (National Council on Radiation Protection and Measurements 1987). The current DOE radiation standards for protection of the public (DOE Order 5480.1A) are 1 mSv/yr for prolonged exposure and 5 mSv/yr for occasional annual exposures for a maximally exposed individual.
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76 THE NUCl~AR WEAPONS COMPLEX TABLE 5.1 Average Lifetime Cancer Mortality per 100,000 Males (Extrapolated from Effects of Acute Exposure to Radiation) Dose Exposure Period (mSv/yr) ~) Leukemia Backgroundb ExcessC Nonle~kemisa Backgrounds ExcessC 10 18-65 780 400 20,140 2,480 0.01 1-99 790 0.7 19,760 4.5 PA dose rate reduction factor had not been applied to Me risk estimate for nonleukemia cancers. Suggested values for such a factor range from 2 to 10 for low dose rate exposures NRC 1990. bPHS 1984- CNRC 1990. population of 10,000 and is impossible to detect the effects of 0.01 mSv/yr on 100,000 people. For comparison, the calculated dose to the "maximally exposed individual" (a hypothetical nearby resident considered to receive the highest possible radiation dose from the facility) at Hanford in 1987 was 0.0005 mSv/yr (Pacific Northwest Laboratory 1988~. Based on the estimates from BEIR V, health effects on the public resulting from this level of exposure from the Hanford site should be negligible. Nonetheless, near the two British fuel reprocessing operations, Sellaf~eld and Dounreay, clusters of excess cases of leukemia among children and young adults have been reported in a population that is believed to have received only low doses (Derby and Doll 1987, Form an et al. 1987~. Although no general increase in other cancers among other age groups has been associated with living in the vicinity of nuclear installations in England and Wales, there is some suspicion of increased multiple myeloma and Hodgkin's disease in adults that requires further study (Form en et al. 1987, Cook-Mozaffari et al. 1987~. Clusters of cancers may be found in population-based epidemiologic studies for a variety of reasons. These include: (1) the estimates in Table 5.1 are grossly inaccurate; (2) the doses have been grossly underestimated; (3) statistical artifacts; or (4) the unexposed, control population to which the study population is compared may not have been appropriately matched. For example, it is possible that there may be a viral cause of childhood leukemia in situations of large-scale population mixing of the sort that takes place in the construction and operation of new nuclear facilities (Kinlen 1988~. Therefore comparisons to leukemia rates in more stable populations would be inappropriate in this case. The resolution of the uncertainties in the interpretation of cancer clusters
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HEALTH 77 requires more data and can only be done from large epidemiologic surveys involving many millions of person-years of exposure. Several international epidemiology studies on low-level radiation and cancer are under way at the International Agency for Research on Cancer (IARC). All European cancer registries are being used to investigate the possible association of childhood leukemias with exposure to radioactive material from the accident at Chernobyl in 1986. In 1988 an international group including DOE representatives began the design of an analysis of radiation worker cohorts and their risk of cancer (preliminarily, a dose-related increase in risk of multiple myeloma was observed). It is estimated that data involving 1.7 million person-years of exposures will be available for this effort a. Esteve, personal communication, IARC 1989~. Designs are also under way to study international utility reactor worker populations with a total of approximately 2 million person-years of exposure (Esteve, personal communication, September 29, 1989~. Although the weight of current scientific evidence suggests that, at the estimated levels of exposure, leukemia clusters reported in the British studies are not the result of radiation exposure, the committee believes that a similar study should be conducted in the vicinity of a DOE facility. Such a study should investigate at least childhood leukemia and adult multiple myeloma. The study could provide relevant information in a different setting and may also serve to assure the local population. Epidemiology on Exposure of Workers Conclusion The Department has compiled a substantial body of data on the exposure of workers to radiation and the status of their health, and it is seeking means to ensure that epidemiologic studies will be conducted using these data. Since the early days of operations in the nuclear weapons complex, the exposure of workers to radiation has been monitored by detection devices, called badges or dosuneters, that are worn by the worker throughout his or her work shift. The data are often stored on incompatible data bases separate from other information about the health of workers, an arrangement that makes it difficult to access and analyze the data. In the recent past, DOE has conducted studies on several groups of workers at selected sites in an effort to relate radiation exposure to cancer mortality. The studies have been conducted primarily by researchers at the DOE national laboratories, although some of the work was carried out at universities under contract to DOE. More peccantly, the mortality of workers at Oak Ridge has been investigated (ORAU 1988~. These research efforts, in spite of their obviously crucial importance, have been disappointingly limited thus far. Studies have focused almost exclusively on gamma-radiation exposures and cancer endpoints.
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78 THE NUCLEAR WEAPONS COMPLY Greater consideration should be given to other radiations, as well as exposures to chemicals, and other effects on health. The Secretary of Energy has recently adopted a four-point initiative on epidemiology as a first step toward addressing these concerns. The initiative calls for the establishment of the Secretarial Panel for the Evaluation of Epidemiologic Research Activities (SPEERA) to provide the epidemiology program with guidance on policy issues, such as goals, management and reporting structure, resource requirements, quality control, records maintenance and access, and similar concerns. The National Research Council's Committee on the Radiation Epidemiologic Research Program (CRERP) is charged to guide the program on scientific issues. Moreover, the Department is committed to the development of a Comprehensive Epidemiologic Data Repository (CEDR), which is to contain relevant data on all current and former DOE contract employees. (These employees number approximately 600,000.) The data will be made available to independent researchers when CEDR becomes operational. The Secretary has also mounted an effort that entails assistance from CRERP to allow independent researchers access to these data before CEDR becomes operational. The Department should be encouraged in its efforts to seek outside advice in areas related to research on epidemiology and dose reconstruction. The involvement of external committees like SPEERA and the National Research Council's CRERP will not only strengthen the technical basis of these efforts, but will also lend credibility to the findings. We believe it is essential that the research be conduced by independent researchers who are trained in epidemiology. Recommendation The Department of Energy should compile data on its workers in a comprehensive, comparable, and accessible data base and should support epidemiologic research using these data. Furthermore, the DOE worker health research studies should be designed and directed independently and subject to peer review by an external organization. Epidemiology on Exposure of the Nonworker Population Conclusion In spite of the limitations imposed by low levels of exposure and small population sizes, dose reconstruction and epidemiology studies can provide a useful mechanismfor addressing public concerns about the potentialfor adverse health effects in areas near weapons facilities. The Department of Energy recognizes that it must address public concerns arising from past and current exposures to radiation released from the weapons complex facilities. This is a singularly difficult task because the interpretation of the scientific data and the assessment of risk are complex, and public perceptions
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HEALTH 79 may not be in accord with scientific understanding. Carefully designed, independently directed dose reconstruction and epidemiologic studies could advance scientific knowledge and may help to improve public understanding. The conduct of such studies requires a careful determination of both exposures and effects. Since exposures to nonworker populations are not measured, doses must be reconstructed by calculations based on whatever data are available. Exposures in recent years can be quantified by using data collected at monitoring stations in communities located near these facilities. In the absence of such monitoring data, dose reconstruction studies combine data on releases of radioactive materials with calculations of the transport and fate of those materials (i.e., how they might move through the environment and ultimately result in an exposure) to estimate levels of exposure to the population. Dose reconstruction studies are, of course, limited by the quality of the available data on releases and by the accuracy of the transport models. It is important that the results of these studies include a thorough analysis of He uncertainties involved. Several dose reconstruction studies are now being conducted in the United States. For example, the National Cancer Institute is supporting work at the University of Utah to conduct dose reconstruction and epidemiologic studies of populations living in the vicinity of atmospheric tests (Wachholz, in press). At Fernald, a dose reconstruction study is being conducted by the Centers for Disease Control. DOE is also supporting a dose reconstruction study at Hanford to estimate the exposures of residents near the facility as a result of historical releases (Till, in press). The Hanford investigation involves the reconstruction of exposures in the 1940s and 1950s as well as the design and execution of a thyroid cancer epidemiologic study by the Centers for Disease Control. The National Cancer Institute is also currently conducting an epidemiologic study of cancer mortality in the vicinity of commercial nuclear power plants in the United States aablon et al. 1988~. The use of independent agencies, panels, and peer-reviewers serves to strengthen the scientific validity of research efforts and to increase the credibility of results. At Hanford, for example, the use of an independent agency and review panel is greatly enhancing both the scientific quality of the study and public confidence in it. Each DOE facility is engaged in unique operations that result in the use of differing combinations of radionuclides and chemicals and thus present unique sets of exposures. As a result, attention to potential health effects should be tailored to each facility. The combination of a dose reconstruction study and epidemiologic analysis can be used to ascertain whether there is evidence of an association bc~wcen exposure and a consistent pattern of disease. Statistical analyses are performed to determine the probability that findings result from an actual effect rather than simply by chance. Thus in studies where exposure levels are rclativcly small and
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80 THE EJECT WAGONS COMPLY the increased incidence of disease is slight, the study population must be large enough to confer s~ishcal significance on the results. Nonetheless, such studies should be undertaken to improve sciendD'c understanding and inform the public. Recommendation The Department of Energy should continue to support dose reconstruction and epidemiologic studies of relationships, if any, between exposure to low levels of radiation from the facilities and the incidence of disease to improve scientific understanding and to inform the public. The studies should be designed and directed independently in a manner that involves public participation and external peer review.
Representative terms from entire chapter: