VII Conclusions

In establishing the program of compensation for atomic veterans, Congress intended to create a program that was responsive, was based on sound science, and treated the veterans fairly and respectfully. The committee recognizes the challenge confronting the Defense Threat Reduction Agency and the Department of Veterans Affairs associated with reconstructing historical doses and making decisions about compensation to thousands of veterans who were exposed decades ago, using records and data that are incomplete and often difficult to piece together. And the committee recognizes that many improvements have been made in the NTPR program since its beginning. The committee has come to understand the frustrations of the veterans who willingly performed their duties under extraordinary circumstances and who are confronted with the burden of seeking compensation for diseases that they believe are related to the service they performed for their country.

The committee has undertaken its work fully cognizant of controversies associated with this important program since its inception. Therefore, it is to be expected that the committee, as discussed in Chapter II, has viewed its scope of work as somewhat broader than that specified in its charge. In addition to responding directly to the questions presented in the statement of task, the committee presents some conclusions related to other aspects of the dose reconstruction program that it hopes will respond to additional questions that have been raised about the atomic-veterans compensation program for many years. It should be understood that the committee’s conclusions about the adequacy of the dose reconstruction program for atomic veterans and other findings represent consensus judgments that were developed on the basis of the preponderance of informa-



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VII Conclusions In establishing the program of compensation for atomic veterans, Congress intended to create a program that was responsive, was based on sound science, and treated the veterans fairly and respectfully. The committee recognizes the challenge confronting the Defense Threat Reduction Agency and the Department of Veterans Affairs associated with reconstructing historical doses and making decisions about compensation to thousands of veterans who were exposed decades ago, using records and data that are incomplete and often difficult to piece together. And the committee recognizes that many improvements have been made in the NTPR program since its beginning. The committee has come to understand the frustrations of the veterans who willingly performed their duties under extraordinary circumstances and who are confronted with the burden of seeking compensation for diseases that they believe are related to the service they performed for their country. The committee has undertaken its work fully cognizant of controversies associated with this important program since its inception. Therefore, it is to be expected that the committee, as discussed in Chapter II, has viewed its scope of work as somewhat broader than that specified in its charge. In addition to responding directly to the questions presented in the statement of task, the committee presents some conclusions related to other aspects of the dose reconstruction program that it hopes will respond to additional questions that have been raised about the atomic-veterans compensation program for many years. It should be understood that the committee’s conclusions about the adequacy of the dose reconstruction program for atomic veterans and other findings represent consensus judgments that were developed on the basis of the preponderance of informa-

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tion available to the committee. Similar judgments are required in performing dose reconstructions. Since it is not possible to determine exactly what happened to the veterans, the committee’s view is that the goal of dose reconstruction is to develop plausible assumptions that yield credible upper-bound estimates of dose, consistent with the requirement to give the veterans the benefit of the doubt. The committee’s conclusions are divided into two groups: those answering the four questions posed in the statement of task; and those related to the establishment of continuing review and oversight of the program. Finally, the committee offers some additional explanation about the implications of its findings. VII.A RESPONSES TO QUESTIONS IN COMMITTEE’S CHARGE Chapter II describes the committee’s difficulty in understanding the intent of some of the questions that were presented in its charge and explains its interpretation of these questions. The questions in the statement of task, the committee’s interpretation of the questions, and responses to the questions are presented below. Question 1. Is the reconstruction of the sample(d) doses accurate? {Because dose reconstruction is inherently uncertain, the committee interprets this question to be whether uncertainty in the sampled doses has been appropriately considered and whether credible upper bounds of doses to atomic veterans have been obtained.} According to the regulations and the objectives of the NTPR program, the goal is to report at least the 95th percentile upper bound of possible doses for each veteran. The committee has concluded, however, that upper-bound doses from external gamma, neutron, and beta exposure are often underestimated, sometimes considerably, particularly when doses are reconstructed as opposed to being based on film-badge data. A number of findings led the committee to that conclusion. Some of these are described below. Methods used by the NTPR program to estimate average doses to participants in various military units from external exposure to photons (mainly gamma rays) and neutrons are generally valid. However, because the specific exposure conditions for any individual often are not well known and the available measurements used as input to calculation models are sparse and highly variable, the resulting estimates of total dose for many participants are highly uncertain. Film-badge data, if available, are considered the dose data of record. The dose inferred from a film-badge reading is estimated by using “high-sided” assumptions. However, in some cases, even film-badge data are more uncertain than reflected by the corresponding upper-bound estimates. Although it is difficult to define the degree of underestimation of credible upper bounds of reconstructed external gamma doses, the committee has con-

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cluded that a credible upper bound often could be 2-3 times the central estimate. In contrast, upper bounds reported by the NTPR program often were only 10-20% above the central estimates. The committee also has concluded that upper bounds of neutron doses are always underestimated, because of neglect of uncertainty in the biological effectiveness of neutrons relative to gamma rays. Beta doses to skin are claimed to be “high-sided” because they are based on multiplying an upper-bound gamma dose by a presumed “high-sided” beta-to-gamma dose ratio. However, the upper-bound gamma dose based on a reconstruction is often too low, and the beta-to-gamma dose ratio is not evidently “high-sided” in all cases. In addition, it appears that estimates of beta dose to skin do not include the dose due to contamination of the skin or clothing. The committee also has concluded that upper bounds of inhalation doses are underestimated in many cases. Estimation of internal dose—most important, the dose from inhalation—is an inherently more difficult problem than estimation of external dose because data that could be used to estimate intakes of radionuclides by the atomic veterans are not available. Given the lack of relevant data, the NTPR program relies on assumptions that are presumed to result in overestimates of concentrations of radionuclides in air, especially assumptions about resuspension factors. The committee has identified many problems with the methods of estimating inhalation doses to atomic veterans. They center around three issues: the unknown reliability of methods of estimating airborne concentrations of radionuclides used by the NTPR program, including the assumption of no fractionation of radionuclides in fallout except for removal of noble gases; the lack of consideration of resuspension of previously deposited fallout by the blast wave produced in detonations at the NTS and the frequent neglect of aged fallout that accumulated during the period of atomic testing at the NTS; and the lack of consideration of uncertainty in inhalation dose coefficients for all radionuclides. In spite of problems with the methods used in the NTPR program to estimate inhalation doses, inhalation doses assigned to many atomic veterans are probably “high-sided” and exceed the 95th percentile goal. However, there are important scenarios involving maneuver troops and close-in observers at the NTS in which credible upper bounds of inhalation doses would exceed the dose estimated by the NTPR program by large factors. Furthermore, in scenarios in which inhalation doses almost certainly were underestimated by large factors, credible upper bounds of organ equivalent doses could be important in some cases. Thus, the committee has concluded that the methods that have been used to estimate inhalation doses to atomic veterans do not consistently provide credible upper bounds of possible doses and that this could be an important deficiency in some exposure scenarios. The possibility of ingestion exposures apparently is not considered routinely in dose reconstructions for atomic veterans. However, except in rare situations,

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neglect of ingestion exposures does not have important consequences with regard to estimating credible upper bounds of total doses to the veterans. The committee has concluded that veterans are not always given the benefit of doubt in developing exposure scenarios and assessing film-badge data. Veterans often were not contacted to verify their exposure scenario, even when such contact was feasible and could have been helpful. In some cases, there was inadequate follow-up with other participants who might have been able to clarify scenario assumptions. In many cases, considerable judgment had to be used in developing exposure scenarios. Nonetheless, applicable regulations are quite clear that a veteran must be given the benefit of the doubt, which would lead to a higher dose, when there is a question regarding his exposure scenario. Although application of benefit of the doubt would not affect doses in all cases in our random sample, the committee found it to be a frequent problem. Thus, the committee has concluded that upper bounds of total doses reported by the NTPR program have often been underestimated and therefore do not provide credible upper bounds (95th percentiles) of possible doses. Question 2. Are the reconstructed doses accurately reported? {The committee interprets this question to be whether the doses that are calculated (regardless of their validity) are being reported accurately to the Department of Veterans Affairs.} On the basis of its review of many case files, the committee has concluded that doses, as they have been calculated by the NTPR program, have been accurately reported to the VA, and to the veterans. However, the committee believes that uncertainty in assigned doses should be carefully explained and reported to the VA when they are used to evaluate claims for compensation and should be explained to the veterans. Question 3. Are the assumptions made regarding radiation exposure based on the sampled doses credible? {The committee interprets this question to be whether the assumptions made to define the veterans’ exposure scenarios and the methods and parameters used in dose reconstruction are reasonable and appropriate.} This question is the most difficult of the four to answer. The committee has concluded that many assumptions regarding veterans’ exposures during atmospheric nuclear-weapons tests are not reasonable and appropriate, given the objective of the NTPR program to estimate credible upper bounds of dose. A large number of separate assumptions are typically required to derive an estimate of dose for most veterans who were exposed. Many of the assumptions being used are indeed reasonable and based on current understanding of the science of historical dose reconstruction. Nevertheless, many key assumptions and methods

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being used are not appropriate and could lead to underestimation of upper bounds of doses to atomic veterans. The committee’s evaluation of this question was severely hampered by a lack of quality control over the conduct and documentation of dose reconstructions, which made it difficult to determine how doses were calculated in many cases. In some cases, documentation of a dose reconstruction is illegible. The lack of comprehensive quality control of dose reconstructions that have been performed diminishes the credibility of the work and has made it difficult for the committee to conduct its review. Providing the veteran the benefit of the doubt when making assumptions about exposure scenarios and estimating dose is critical to implementation of applicable regulations. It is evident to the committee that there has not been a consistent application of the requirement to give the benefit of the doubt to atomic veterans. The inconsistency affected assumptions made about exposure scenarios and yielded upper-bound doses that clearly were too low in a number of cases. The committee thus has concluded that in many of the cases reviewed, key assumptions about input values and exposure scenarios were not reasonable and appropriate and that this led to reported upper bounds of external and internal doses that fall short of the 95th percentile goal. Question 4. Are the data from nuclear weapons tests used by DTRA as part of the reconstruction of sampled doses accurate? {The committee interprets this question to be whether the historical data and uncertainty in the data have been comprehensively compiled and are suitable for use in historical dose reconstruction.} The committee believes that historical records provide sufficient data to permit doses to be reconstructed for atomic veterans. There is a large repository of information from which to draw data about exposures. In addition, the committee believes that the veterans themselves are a valuable source of information about their own exposures. Although some attempts have been made to contact veterans and seek their input about scenarios of exposure, this source of information seems to be underused. The science of historical dose reconstruction has evolved over the last few decades. In some situations, historical doses have been estimated on the basis of less information than appears to be available for the atomic veterans. The necessary background information is available on which to base the atomic veterans’ dose reconstructions. All in all, the committee was impressed with the large amount of information that has been brought together. The committee has concluded that the radiological and historical information compiled by the NTPR program is suitable and sufficient for use in historical dose reconstruction for the atomic veterans.

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VII.B RECOMMENDATIONS REGARDING A SYSTEM FOR PERMANENT REVIEW OF THE DOSE RECONSTRUCTION PROGRAM The final charge in the statement of task asks the committee to provide recommendations, if appropriate, regarding a permanent system of review of the dose reconstruction program of DTRA. Before discussing the issue of review, we should note that about 70% of all dose reconstructions have been performed in response to veterans’ claims for compensation for nonpresumptive diseases. Furthermore, many of the diseases for which doses have been reconstructed are now included in the presumptive regulation. With the exception of reconstructions of doses to skin, including doses from exposure to beta particles, in response to skin-cancer claims, it is clear to the committee that in most cases, even revised upper-bound dose estimates would be too low to conclude that the veteran’s disease was at least as likely as not caused by his radiation exposure and thus to justify awarding claims. If the program of dose reconstruction continues, the committee believes that an external and independent system of review and oversight is needed. The degree of review and oversight should be commensurate with the anticipated scope of the compensation program in the future. Although the responsibility for a permanent system of review rests with DTRA and VA, the committee provides some guidelines below that may be helpful in its design and implementation. One approach to continuing review and oversight among possible alternatives is to create an advisory board. The board should consist of persons who can evaluate the many facets of the program, such as historical dose reconstruction, radiation risk and probability of causation, communication with the veterans and between VA and DTRA, quality assurance, and historical research related to service experience. The advisory board should include at least one representative of the atomic veterans. In addition to review and oversight of the dose reconstruction program of DTRA, review and oversight of the program as a whole, including the responsibilities of DTRA and VA in the administration of the atomic veterans’ program, is desirable. The advisory board should meet frequently enough to understand the program fully, to conduct random audits of doses being reconstructed and decisions regarding claims, to review methods, and to recommend changes when needed. The advisory board should meet with atomic veterans regularly, listen to their concerns, and ensure that their concerns are addressed. The board should also help DTRA and VA in efforts to provide information to veterans that effectively communicates the program’s mission and process and the science related to possible health effects of radiation exposures of atomic veterans.

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VII.C EXPLANATION TO ATOMIC VETERANS REGARDING IMPLICATIONS OF COMMITTEE’S FINDINGS The committee is sympathetic to many of the atomic veterans’ concerns and frustrations. Furthermore, although the number is probably small, the committee believes that some veterans would have been compensated if more-credible upper bounds of dose had been estimated in dose reconstructions. The committee also believes, as has been reported to and stated by the atomic veterans, that the total number of claims awarded under the nonpresumptive regulation since its promulgation is small (on the order of 50), excluding recent awards for skin cancer. That illustrates clearly that when a veteran files a claim for a disease under the nonpresumptive regulation, the probability is very low that an award will be granted. The committee is concerned that this small chance of success has not been clearly reported in the past. The committee also believes, however, that it is important for the veterans to understand that there are legitimate reasons for the low number of successful claims for nonpresumptive diseases, and that these reasons are unrelated to deficiencies in the methods of dose reconstruction used in the NTPR program. On the basis mainly of data obtained from studies of the Japanese atomic-bomb survivors, it is evident that ionizing radiation is not a potent cause of cancer. That is indicated, for example, by the small number of excess cancers that have been observed in the atomic-bomb survivors, even though many in this population received doses much higher than the doses received by nearly all atomic veterans. That conclusion is also indicated by screening doses given in Table III.E.4 (see Section III.E) that are based on the current IREP method of calculating probability of causation of cancers. The screening doses, which correspond to a 99% confidence limit in an estimated probability of causation of 50% and are based on an assumption that cancer risk is a linear function of dose, without threshold, are 10 rem or greater for most cancers listed in the table; this indicates that high doses are required to give an appreciable probability of causation of cancer. For many cancers, the screening doses that have been used by VA to evaluate claims for compensation also are 10 rem or greater (see Tables III.E.3 and III.E.4). Furthermore, on the basis of what is known about conditions of exposure of atomic veterans, credible upper bounds of doses received by most veterans almost certainly would be so low that the probability that a cancer was due to radiation exposure in the atomic-testing program is small. The committee notes that the established policy of using upper-bound estimates of dose (95th percentiles) with the more extreme lower-bound estimates of doses that correspond to a 50% probability of causation of various cancers is highly favorable to the veterans’ interests. If credible upper bounds of dose are obtained in dose reconstructions, atomic veterans can be compensated for nonpresumptive diseases even when the true probability that radiation exposure caused the diseases is low.

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None of that is to say that the veterans do not have legitimate complaints about their dose reconstructions; in many cases, the committee believes they do. Rather, the committee hopes that veterans will understand that their radiation exposure probably did not cause their cancers in most cases and that reasonable changes in methods of dose reconstruction in response to this report are not likely to greatly increase their chance of a successful claim for compensation when a dose reconstruction is required.