## Introduction

**Contents:** This chapter provides an introduction to the full report.
It includes a discussion of why this project was undertaken, what is
included in the project, and what is beyond the scope of this effort.
The organization of this report is briefly described.

### Background

In 1998, Congress provided funding for the Department of Health and
Human Services (DHHS) to study the health impact on American peoples of
radioactive fallout. More specifically, the Committee on Appropriations
of the United States Senate reported the following (U.S. Senate 1998):

"The Committee has allocated \$1,850,000 with the emergency fund for a
study of the health consequences to the American population of nuclear
weapons tests conducted by the United States and other nations. The
Committee expects the Centers for Disease Control and Prevention to be
the lead agency on the study, with the support of the National Cancer
Institute. The Department should conduct an initial assessment of the
feasibility and public health implications of such a study. The
assessment ought to address major issues such as: radiation dose
estimation and risk assessment, appropriate epidemiologic
investigations, and health communication strategies for promoting better
understanding of the research by the general public. In developing the
assessment, design, and conduct of the study, the Department is expected
to include input from the public and the Advisory Committee on
Energy-Related Epidemiologic Research. In conducting the study, the
Department ought to give high priority to examining the health
consequences of exposure among both the general and high-risk
populations to the full range of radionuclides produced by a nuclear
weapons test. The Committee expects to be informed of the study's
progress on a regular basis and expects to receive a final report by
July 1, 2000."

This action by Congress followed the release of the National Cancer
Institute's (NCI) report *Estimated Exposures and Thyroid Doses Received
by the American People from Iodine-131 in Fallout Following Nevada
Atmospheric Nuclear Bomb Tests* (NCI 1997). This report provided
county-level estimates of the potential radiation doses to the thyroid
for American citizens resulting from atmospheric nuclear weapons testing
at the Nevada Test Site (NTS) in the 1950s and 1960s. A summary of the
NCI report is presented in Appendix B. DHHS' Advisory Committee for
Energy-Related Epidemiologic Research (ACERER) subsequently recommended
that DHHS "(c)omplete a comprehensive dose reconstruction project for
NTS fallout" (ACERER 1998). (The charter for ACERER has since expired
and the committee no longer exists.) In a review of the NCI report
performed at the request of DHHS, the Institute of Medicine (IOM)
concluded that additional research to estimate the total radiation
exposure resulting from the deposition of all radionuclides released as
a result of nuclear weapons testing would be of limited public health
value (IOM 1999). The IOM acknowledged, however, that the public might
desire such an effort to obtain a more complete accounting of the
potential health impact of nuclear weapons testing on American
populations.

This report presents the technical results of an initial assessment of
the feasibility and public health implications of a detailed study of
the health consequences of nuclear weapons testing. In developing all
aspects of the study, the Centers for Disease Control and Prevention
(CDC) and NCI have actively solicited input from the public and from
ACERER. Both written and oral progress reports were made to ACERER and
Congressional staff members during the course of the project. Copies of
the written progress reports were available for public review, and
written and oral comments were received. Appendix C includes a summary
of some of these activities. In addition, the final draft report was
peer reviewed by the National Academy of Sciences' Committee on
Assessment of CDC Radiation Studies (NAS/NRC 2003).

### Scope of work

#### Feasibility study

CDC and NCI were not asked to complete an extensive study of the health
consequences to American people of nuclear weapons tests conducted by
the United States and other nations, but rather to assess feasibility
only. Hence, instead of developing new tools or gathering all possible
data and information that is necessary to perform an extensive, detailed
study of this type, a review of previous studies supplemented with
extensive but rudimentary calculations was used to evaluate the
feasibility of a detailed study. The information that is readily
available on the doses from radioactive fallout from nuclear weapons
tests includes: (1) the NCI (1997) report related to the thyroid doses
from ^131^I produced by atmospheric nuclear weapons tests conducted at
the NTS; (2) several publications related to the estimation of doses
received by the populations who lived in proximity of the NTS (e.g.,
Church et al. 1990); and (3) miscellaneous pieces of information related
to global fallout due mainly to atmospheric nuclear weapons tests
conducted on islands in the Pacific Ocean and in the former Union of
Soviet Socialist Republics (U.S.S.R.). The United Nations Scientific
Committee on the Effects of Atomic Radiation (UNSCEAR) has analyzed some
of this information in order to derive average doses over the population
of northern and southern hemispheres (e.g., UNSCEAR 2000).

In this feasibility report, estimates are provided of the radiation
doses received by American people in the contiguous 48 states as a
result of the atmospheric nuclear weapons tests conducted by the United
States, the former U.S.S.R., and the United Kingdom (U.K.). Only
above-ground nuclear weapons tests conducted from 1951 through 1962 are
considered in this report. Atmospheric nuclear explosions conducted by
France and China, as well as underground nuclear explosions from any
nation, are not considered in this feasibility report, as it is
generally acknowledged that the most important contributions to the
radiation exposures arose from atmospheric nuclear tests conducted by
the United States, U.K., and the former U.S.S.R during the pre-1962 time
period.

Doses due to external exposure from radionuclides deposited on the
ground and internal exposures from ingestion of contaminated foods are
estimated for each county of the contiguous states for the most
sensitive organs and tissues. These dose estimates are based on an
initial review of the open literature, and they are not derived from
sophisticated computer programs that could be designed for that purpose.
They are, however, a significant extension of previously reported dose
estimates, especially for fallout from non-NTS 'global' sources.
Ingestion dose estimates are provided for 19 different radionuclides for
fallout from NTS. Based upon the screening calculations performed for
previous fallout studies, these radionuclides account for at least 95%
of the dose through ingestion of contaminated foods to each organ (Ng et
al. 1990). Two additional radionuclides, ^3^H and ^14^C, are considered
for global fallout. Doses due to inhalation of radionuclides were not
considered in this initial feasibility report, but they have generally
been found to be much smaller than those due to ingestion.

The estimated doses that are presented for NTS and global fallout are
significantly different with regard to their precision and reliability.
Doses from NTS are based on a large database and a significant amount of
previous work in the area of dose estimation. Approximate estimates of
the uncertainty associated with these dose estimates are provided.
Estimates of doses from global fallout, however, are based on a much
more limited database and on previous dose estimates that have been
averaged over large geographic areas. The dose estimates presented here
for any particular county are probably quite imprecise, and the exposure
rate probably varied significantly from place to place within a county.
Not enough data were available to allow for the quantification of the
uncertainty associated with the doses from global fallout.

In addition to providing rudimentary estimates of dose, this report also
addresses the feasibility of utilizing these doses and other information
in a risk analysis to characterize the effects of global fallout on the
health of people in the United States. As a simple example to
demonstrate the feasibility of estimating lifetime cancer risk due to
exposure to radioactive fallout, estimates of the average lifetime risk
of developing all cancers, leukemia, and thyroid cancer are presented
for the United States population. This report also presents a brief
review of ongoing epidemiologic studies being conducted in the United
States and elsewhere. Finally, the report provides the outline of the
strategy and issues that could be considered in developing a
comprehensive health communication plan for affected citizens if a
detailed study is undertaken.

#### Public health implications

An important aspect of this project is consideration of the public
health implications of a detailed study. CDC and NCI acknowledge that
some people desire that the most detailed dose and risk assessment
possible be done so they will know more about their radiation exposure
from nuclear weapons fallout. Also, additional studies may contribute to
our scientific knowledge of the health effects of ionizing radiation.
The question that should also be addressed is whether or not an
appropriate public health intervention will result from performing such
studies. The answer to that question is complex and must be evaluated in
terms of public interest, the Government's commitment to closure of
'fallout' related issues, and the severity of the risk from fallout
compared to other hazards in today's environment which might be remedied
by use of the same funding.

Also, CDC and NCI generally understand public health as "(t)he science
and art of preventing disease, prolonging life, and promoting health
through organized efforts of society" (Acheson Report 1988). Dose and
risk analyses can help in the identification of the likelihood of
diseases that in turn can potentially be treated or prevented. The very
rudimentary results presented in this report suggest that science is
unlikely to provide a public health impetus for conducting more detailed
fallout-related studies. However, given the history of secrecy
associated with the development and testing of nuclear weapons and
documented and intentional radioactive releases as well as human
radiation experiments, the Federal Government must be sensitive to the
views of some Americans about the United States, global weapons
programs, and the Government\'s responsibilities. This legacy of
mistrust has developed over the past half-century, and it presents a
formidable social and political context within which to perform studies
and communicate results. Resolution of these issues would require
assistance from agencies other than CDC and NCI.

### Issues outside the scope of this report

One issue related to examining the health consequences resulting from
nuclear weapons tests is that of medical screening of individuals for
potential radiogenic diseases. In their review of the NCI report on NTS
thyroid doses, the IOM recommended against a program to systematically
screen either the American population in general or any population
subgroup for thyroid cancer (IOM 1999). However, ACERER has recommended
that DHHS "(f)urther evaluate screening opportunities for thyroid
cancer...\[and\] to evaluate the advisability and feasibility of
screening for other (noncancerous) thyroid and parathyroid diseases,
with a priority to evaluate this service for those at highest risk due
to their exposures" (ACERER 1998). CDC and NCI are continuing dialogue
with stakeholders on the issue of thyroid screening. As a result of any
future work related to studying the potential public health impact on
American populations of nuclear weapons testing, there may be other
potentially radiogenic diseases where discussion of screening is
appropriate.

American people living around nuclear weapons development and production
sites may have been exposed to radionuclides released from these sites
as well as to radionuclides in weapons testing fallout. Extensive dose
reconstruction and risk assessment activities have been completed for
some of these sites, e.g., the former Feed Materials Production Center
near Fernald, Ohio, and similar activities are underway at other sites,
e.g., the Savannah River Site near Aiken, South Carolina. There are
still other sites where no such activities are underway or planned for
the future, e.g., the Gaseous Diffusion Plant at Portsmouth, Ohio.
Another group for which attempts have been made to reconstruct doses is
military personnel exposed during nuclear weapons tests (NRC 1985). Some
stakeholders have suggested that a method should be developed to add up
doses from these multiple exposures for affected individuals. A
discussion of the technical and communication issues associated with
such a program of adding doses is beyond the scope of this report.

The doses estimated in this report that arise from the ingestion of
contaminated food depend greatly on the values chosen for the amount of
different foods that are eaten by people. The values of food intake used
in this feasibility report are based on averages developed for a
previous assessment of NTS doses (Breshears et al. 1989). These values
may not be appropriate for all people in the United States, including
members of Native American tribes. A more detailed breakdown of food
consumption, however, is beyond the scope of this project.

### Organization of this report

This feasibility report continues with discussion of how, when, and
where radionuclide fallout was created during the testing of nuclear
weapons in the atmosphere (Chapter 2). Rudimentary county-level dose
estimates are provided for people living in the 48 contiguous states for
a number of radionuclides of potential biologic significance from both
NTS and global fallout (Chapter 3). Next, a brief literature overview of
the potential effects of radiation on the health of people is presented,
including a discussion of epidemiologic investigations (Chapter 4). In
this same chapter, dose estimates are used to estimate the average risk
to the American population of developing all cancers, leukemia, and
thyroid cancer from fallout to demonstrate the feasibility of estimating
risk for selected health outcomes. Next, a discussion of the issues that
must be addressed if a plan is to be developed to communicate the
results of a detailed study to the American public is presented (Chapter
5). Finally, the overall results of this study are summarized and
options that might be considered for further activities are presented
(Chapter 6). Many technical terms are used in the body of this report.
These terms are defined when they are first used. To assist the reader
further, a Glossary of terms is provided following Chapter 6. A number
of appendices provide additional technical details for some of the
material presented in the main body of the report.

**References**

Acheson Report. Public Health in England: The Report of the Committee of
Inquiry into the Future Development of the Public Health Function, Cmnd.
289. London: Her Majesty's Stationery Office (1988).

Advisory Committee for Energy-Related Epidemiologic Research (ACERER).
Resolution containing six recommendations concerning the Department of
Health and Human Service's follow-up to the NCI study (October 1998).

Breshears, D. D., T.B. Kirchner, M.D. Otis, and F.W. Whicker.
Uncertainty in predictions of fallout radionuclides in foods and of
subsequent ingestion, Health Phys. 57:943--953 (1989).

Church, B.W., D.L. Wheeler, C.M. Campbell, R.V. Nutley, and L.R.
Anspaugh. Overview of the Department of Energy's Off-Site Radiation
Exposure Review Project (ORERP), Health Physics 59(5): 503-510 (1990).

Institute of Medicine (IOM)/ National Research Council. Exposure of the
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the National Cancer Institute Report and Public Health Implications.
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National Cancer Institute. Estimated Exposures and Thyroid Doses
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of the American Population to Radioactive Fallout from Nuclear Weapons
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National Research Council, Committee on Dose Assignment and
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Nuclear Weapons Tests. National Academy Press, Washington, DC (1985).

United Nations Scientific Committee on the Effects of Atomic Radiation.
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U.S. Senate. Senate Appropriations Bill Report 105-300, pages 197-198 to
accompany S.2440 \[PL 105-277\]. Washington, DC (1998).