United States Science Advisory EPA-SAB-RAC-95-009
Environmental Board (1400F) Marcn 1995
Protection Agency
AN SAB REPORT: A
RETROSPECTIVE
REVIEW OF SAB/RAC
ACTIVITIES
A RETROSPECTIVE REVIEW OF SAB/RAC
ACTIVITIES: A SELF-INITIATED REVIEW
AND ANALYSIS OF THE REVIEWS
CONDUCTED DURING THE FIRST
DECADE OF OPERATION OF THE
RADIATION ADVISORY COMMITTEE
(1985 - 1994) IN SERVICE TO THE
ENVIRONMENTAL PROTECTION AGENCY
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March 30, 1995
EPA-SAB-RAC-95-009
Honorable Carol M. Browner
Administrator
U.S. Environmental Protection Agency
401M Street, S.W.
Washington, D.C. 20460
Dear Ms. Browner:
In 1992, the Radiation Advisory Committee (RAC), on its own initiative, undertook a
retrospective review of its activities from its unofficial inception and subsequently as a stand-alone
committee from Fiscal Year (FY) 85 to the present.
While the compilation of this review was underway, the Science Advisory Board (SAB)
under its Chair, Dr. Matanoski, encouraged each of the SAB Committees to review its activities
over the past several years as a part of the Board's FY 1994 activity to "reinvent the SAB." The
intent of the retrospective review is to refresh the SAB's collective memory, identify highlights
and lowlights, and generally develop a list of lessons that can suggest quality improvements in the
way that the Board carries out its mission of providing the Agency with advice on scientific and
technical issues coming before the Agency.
The attached report from the RAC is more extensive than requested by the SAB's
Executive Committee and represents a significant effort to collect, review and learn from the
Committee's experience. The Committee has been particularly fortunate to have had Dr. Oddvar
F. Nygaard, former Chair of the RAC, to provide information and perspective, as well as the
major part of writing and editing to make this report a reality. Dr. Nygaard is the only member of
the RAC who has served continuously throughout the period of this review, which covers FY 85
to the present.
While this report has been prepared primarily for the use of the RAC and the Board in its
own self study, we felt that it was important to share the report with you as well. We believe that
the Agency will benefit — as have we — from looking back upon where we have been so as to gain
insight on where we are going. We look forward to working with you to make appropriate
course adjustments that may improve the process.
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This retrospective review examines forty-five SAB reports focusing specifically on
radiation issues. The bulk of the reports are reviews that were made at the request of the Agency,
but there are also a number of self-initiated communications, some of which may have had
significant impact. The topics cover a multitude of scientific, technical and engineering aspects of
radiation, including estimating risks from both ionizing and nonionizing radiation, National
Emission Standards for Hazardous Air Pollutants (NESHAP), radionuclides in drinking water,
radioactivity management and waste disposal issues, release of carbon-14 in gaseous form from
high-level waste, numerous radon-related issues (including radon measurement and mitigation,
radon research recommendations, the National Residential Radon and the National School Radon
Surveys, the Citizen's Guide to Radon as well as the Homebuyer's and Seller's Guide to Radon),
Naturally Occurring Radioactive Materials (NORM), drinking water wastes containing NORM,
quantitative uncertainty analysis for radiological assessments, and harmonizing chemical and
radiation risk-reduction strategies.
Some of our reviews have contained elements that certainly "nudge" the science and
policy interface. The role of SAB is principally as an advisor on the scientific and technical
aspects of EPA issues. At the same time, however, we recognize that the science and policy
interface is, in reality, a continuum along which an inextricable linkage of science and policy can
be found at many points. We believe that we serve you and the Agency best by being aware of
our principal responsibilities in the scientific and technical realm which include, when appropriate,
alerting you to the technical aspects of policy choices involved.
We call your attention particularly to the "lessons learned" portion of this report (see
Section 10), where we have summarized some experiences and concerns that we wish to share.
Some of the main conclusions and recommendations drawn from out ten-year experience are
listed below.
1) Independent peer review of the Agency's documents is important to ensure that the
development of the Agency's environmental policies are based on strong science. The
RAC believes that it serves a useful function in this regard, and that it is as a whole,
through the interaction among its members, that it achieves its greatest strength.
2) The RAC believes that in order to best serve the Agency, it should, when appropriate,
alert the Agency to the scientific and technical ramifications of various policy choices,
including through the preparation of self-initiated Commentaries or reports.
3) The average Committee member is relatively uninformed about the SAB's overall
scope of operation and appears to have minimal or no input in matters such as nomination
of new Committee members and the selection of documents to accept for review.
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4) A practical problem in the relationship between the Committee and the SAB is the
periodic shortage of staff support for the preparation of Committee reports.
5) The Agency should make a greater effort to ensure that the documents to be reviewed
have been previewed internally for overall quality, especially when prepared by outside
contractors. An additional way to facilitate the Committee's effort is to make the charge
to the Committee as specific and clearly stated as possible.
6) The Agency's response to a Committee's review constitutes a very essential feedback
and it is especially important that the Agency describe its reason(s) for not following the
Committee's recommendations. A potential risk to be guarded against is the assumption,
or perception, that a review by an SAB committee implies a complete endorsement of the
document reviewed, which many times is not the case.
7) The Agency, through its program offices should give the Committees early warnings
about issues in which the Agency plans to involve the Committee. Since a Committee
cannot be expected to address every issue that relates to its expertise, it would be useful
for the Committee to be informed about such issues that it will not be asked to review in
order that it may be able to view its involvement in the context of the Agency's overall
agenda. The Committee members would also benefit from a better understanding of the
EPA's organizational structure and functions, through written material or briefings by
staff.
These lessons certainly suggest avenues for further development and involvement in our future
relationships with the Agency and the Science Advisory Board.
In addition to the items discussed above, there are continuing concerns regarding issues
and recommendations that have come up in the RAC's reviews and commentaries. A number of
these have been listed at the end of Section 10.
We deeply appreciate the cooperation that the RAC has received from the Agency over
the past decade. We look forward to a future that will build on that past and will improve upon
what we have done together.
In closing, we would certainly be interested in receiving any reaction you might have to
this retrospective study. In particular, we invite you to meet with the SAB's Executive
Committee and the RAC during FY 1995 to help us plot a course that may serve the Agency even
better in the future.
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We look forward particularly to your thoughts on our findings and recommendations
resulting from this retrospective analysis.
Sincerely,
Dr. Genevieve M. Matanoski Dr. James E. Watson, Jr.
Chair, Executive Committee Chair, Radiation Advisory Committee
Science Advisory Board Science Advisory Board
Dr. OddvarF. Nygaard
Past Chair and Principal Writer
Radiation Advisory Committee
Science Advisory Board
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NOTICE
This report has been written as a part of the activities of the Science Advisory Board, a
public advisory group providing extramural scientific information and advice to the Administrator
and other officials of the Environmental Protection Agency. The Board is structured to provide a
balanced, expert assessment of scientific matters related to problems facing the Agency. This
report has not been reviewed for approval by the Agency; hence, the comments of this report do
not necessarily represent the views and policies of the Environmental Protection Agency or of
other Federal agencies. Any mention of trade names or commercial products does not constitute
endorsement or recommendation for use.
The Radiation Advisory Committee (RAC) wishes to acknowledge with grateful
appreciation that the bulk of this report was prepared by Dr. Oddvar F. Nygaard, former Chair of
the SAB's RAC. This report was initiated during the last year of Dr. Nygaard's term and was
largely completed during the term of the subsequent Chair, Dr. Genevieve M. Matanoski. Dr.
James E. Watson, Jr., is currently Chair of the SAB's RAC.
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ABSTRACT
The Radiation Advisory Committee (RAC) of the Science Advisory Board (SAB) carried
out this self-initiated retrospective review of all its reports to the Agency generated over the first
decade of the Committee's existence. In addition to reviews of issues and documents presented
to it by the Agency, primarily the Office of Radiation and Indoor Air (ORIA), a number of reports
and shorter communications were produced on issues that the RAC believed to be important to
call to the Agency's attention. Besides serving as a "road map" to the Committee's past activities,
the report also serves as a mirror for the issues that have required the EPA's attention in the
radiation field as well as how some of these issues have developed over the ten-year period
covered by the report. Finally, the report has served as a means for the RAC to evaluate its
performance over this span of time and has formed the basis for certain conclusions and
recommendations relating to the Committee's interaction with the Science Advisory Board and
with the Agency at large.
Key Words: Ionizing Radiation, Nonionizing Radiation, Radioactive Waste Disposal,
Radioactivity Management, Radiation Issues, Radiation Risk, Radon Related Issues,
Radionuclides in Drinking Water, Risks from Radiation Exposures, Uncertainty Analysis
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hair
SCIENCE ADVISORY BOARD
RADIATION ADVISORY COMMITTEE
Dr. James E. Watson, Jr., Professor, Department of Environmental Sciences and Engineering,
University of North Carolina at Chapel Hill, NC
Members and Consultants
Dr. William J. Bair, (Retired) Director, Battelle Pacific Northwest Laboratory, Richland,
Washington
Dr. Stephen L. Brown, Director, R2C2 (Risks of Radiation and Chemical Compounds),
Oakland, CA
Dr. June Fabryka-Martin, Staff Scientist, Chemical Science and Technology Division, Los
Alamos National Laboratory, Los Alamos, NM
Dr. Ricardo Gonzalez, Associate Professor, Department of Radiological Sciences, University of
Puerto Rico School of Medicine, San Juan, PR
Dr. David G. Hoel, Chairman and Professor, Department of Biometry and Epidemiology,
Medical University of South Carolina, Charleston, South Carolina
Dr. F. Owen Hoffman, President, SENES Oak Ridge, Inc., Center for Risk Analysis, Oak Ridge,
TN
Dr. Bernd Kahn, Professor, School of Nuclear Engineering and Health Physics, and Director,
Environmental Resources Center, Georgia Institute of Technology, Atlanta, GA
Dr. Arjun Makhijani, President, Institute for Energy and Environmental Research, Takoma
Park, MD
Dr. James E. Martin, Associate Professor of Radiological Health (and Certified Health
Physicist), University of Michigan, School of Public Health, Ann Arbor, MI
Dr. Oddvar F. Nygaard, Professor Emeritus, Division of Radiation Biology, Department of
Radiology, School of Medicine, Case Western Reserve University, Cleveland, OH
Dr. Richard G. Sextro, Staff Scientist, Indoor Environment Program, Lawrence Berkeley
Laboratory, Berkeley, CA
m
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Science Advisory Board Staff
Dr. K. Jack Kooyoomjian, Designated Federal Official, U.S. EPA, Science Advisory Board
(1400F), 401 M Street, S.W., Washington, D.C. 20460
Mrs. Diana L. Pozun, Secretary
Dr. Donald G. Barnes, Staff Director
IV
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TABLE OF CONTENTS
1. EXECUTIVE SUMMARY 1
2. INTRODUCTION 3
2.1 Preamble 3
2.2 Historical Notes on the Radiation Advisory Committee 3
2.3 Overview of the Present Report 3
3. ESTIMATING RISKS FROM IONIZING RADIATION 5
3.1 Risks from Low-LET Radiation 5
3.2 Radon Risk Estimates 8
4. NATIONAL EMISSION STANDARDS FOR HAZARDOUS AIR POLLUTANTS
(NESHAP) 10
5. RADIONUCLIDES IN DRINKING WATER 16
5.1 Drinking Water Criteria Documents 16
5.2 Proposed Drinking Water Regulation in Relation to "Reducing Risk" Report.... 19
5.3 Closing Comments on Revised Drinking Water Criteria Documents 20
5.4 Drinking Water Treatment Wastes Containing NORM 21
5.5 Chafee-Lautenberg Amendments 22
6. RADIOACTIVITY MANAGEMENT AND WASTE DISPOSAL 24
6.1 Idaho Radionuclide Exposure Study 24
6.2 Residual Radioactivity 27
6.3 Naturally Occurring Radioactive Materials (NORM) 28
6.4 High-Level Radioactive Waste Disposal 29
6.5 Release of Carbon-14 in Gaseous Form from High-Level Waste. ... 32
6.6 Low-Level Radioactive Waste Disposal 33
7. RADON RELATED ISSUES 36
7.1 Radon Epidemiology Proposal 36
7.2 Radon Measurement and Mitigation 37
7.3 Radon Science Initiative 41
7.4 National Residential Radon Survey 43
7.5 National School Radon Survey 45
7.6 Citizen's Guide to Radon 46
7.7 Homebuyer's and Seller's Guide to Radon 46
v
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VI
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TABLE OF CONTENTS: CONTINUED
8. NON-IONIZING RADIATION 49
8.1 Earlier Concerns about the Non-Ionizing Radiation Program 49
8.2 Potential Carcinogenicity of Electromagnetic Fields 51
8.3 Research Strategy for Electric and Magnetic Fields 51
9. MISCELLANEOUS GENERIC REPORTS 53
9.1 Status of EPA Radionuclide Models 53
9.2 Harmonizing Chemical and Radiation Risk-Reduction 55
9.3 Quantitative Uncertainty Analysis for Radiological Assessments 57
10. LESSONS LEARNED - EXPERIENCE AND OPINIONS 59
10.1 The Committee 59
10.2 Dealing with the SAB 60
10.3 Dealing with the Agency 61
10.4 Other Issues 62
10.5 Continuing Concerns Regarding Issues Reviewed 63 10.6
Concluding Comments 64
APPENDIX A - EPA-SAB-RAC REPORTS REVIEWED
APPENDIX B - RELEVANT REFERENCES
APPENDIX C - RADIATION ADVISORY COMMITTEE CHARTER
APPENDIX D - LIST OF RADIATION ADVISORY COMMITTEE CHAIRS,
COMMITTEE MEMBERS, AND CONSULTANTS
APPENDIX E - GLOSSARY OF TERMS AND ACRONYMS
VII
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1. EXECUTIVE SUMMARY
The Radiation Advisory Committee (RAC) of the U.S. Environmental Protection Agency's
(EPA's) Science Advisory Board (SAB) was established in FY 1985 as a standing committee "to
review and evaluate the scientific basis and quality of the Agency's risk assessments, research, and
other scientific activities related to environmental radiation."
This retrospective review examines, in Sections 3 through 9, forty-five SAB reports
focusing specifically on radiation issues. The bulk of the reports are reviews that were made at
the request of the Agency, but there are also a number of self-initiated communications, some of
which may have had significant impact. The topics cover a multitude of scientific, technical and
engineering aspects of radiation, including estimating risks from both ionizing and nonionizing
radiation, National Emission Standards for Hazardous Air Pollutants (NESHAP), radionuclides in
drinking water, radioactivity management and waste disposal issues, release of carbon-14 in
gaseous form from high-level waste, numerous radon-related issues (including radon measurement
and mitigation, radon research recommendations, the National Residential and the National
School Radon Surveys, the Citizen's Guide to Radon as well as the Homebuyer's and Seller's
Guide to Radon), Naturally Occurring Radioactive materials (NORM), drinking water wastes
containing NORM, quantitative uncertainty analysis for radiological assessments, and harmonizing
chemical and radiation risk-reduction strategies.
The primary role of the Committee has been to serve as an independent reviewer of
scientific analyses used to estimate the impact of radiation on the environment and human
populations for EPA's rulemaking activities, provide advice to the Agency regarding technology
developments, and identify priority research, monitoring, and other scientific needs to support
regulatory activities. Notwithstanding the strong emphasis on dealing with evaluation of scientific
and technical issues, the Committee believes that in order to best serve the Agency, it should,
when appropriate, alert the Agency to the technical ramifications of various policy choices.
We call your attention particularly to the "lessons learned" portion of this report (see
Section 10), where we have summarized some experiences and concerns that we wish to share.
Some of the main conclusions and recommendations drawn from out ten-year experience are
listed below as follows:
1) Independent peer review of the Agency's documents is important to ensure that the
development of the Agency's environmental policies are based on strong science. The
RAC believes that it serves a useful function in this regard, and that it is as a whole,
through the interaction among its members, that it achieves its greatest strength.
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2) The RAC believes that in order to best serve the Agency, it should, when appropriate,
alert the Agency to the scientific and technical ramifications of various policy choices,
including through the preparation of self-initiated Commentaries or reports.
3) The average Committee member is relatively uninformed about the SAB's overall
scope of operation and appears to have minimal or no input in matters such as nomination
of new Committee members and the selection of documents to accept for review.
4) A practical problem in the relationship between the Committee and the SAB is the
periodic shortage of staff support for the preparation of Committee reports.
5) The Agency should make a greater effort to ensure that the documents to be reviewed
have been previewed internally for overall quality, especially when prepared by outside
contractors. An additional way to facilitate the Committee's effort is to make the charge
to the Committee as specific and clearly stated as possible.
6) The Agency's response to a Committee's review constitutes a very essential feedback
and it is especially important that the Agency describe its reason(s) for not following the
Committee's recommendations. A potential risk to be guarded against is the assumption,
or perception, that a review by an SAB committee implies a complete endorsement of the
document reviewed, which many times is not the case.
7) The Agency, through its program offices should give the Committees early warnings
about issues in which the Agency plans to involve the Committee. Since a Committee
cannot be expected to address every issue that relates to its expertise, it would be useful
for the Committee to be informed about such issues that it will not be asked to review in
order that it may be able to view its involvement in the context of the Agency's overall
agenda. The Committee members would also benefit from a better understanding of the
EPA's organizational structure and functions, through written material or briefings by
staff.
These lessons certainly suggest avenues for further development and involvement in our future
relationships with the Agency and the Science Advisory Board.
In addition to the items discussed above, there are continuing concerns regarding issues
and recommendations that have come up in the RAC's reviews and commentaries. A number of
these have been listed at the end of Section 10.
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2. INTRODUCTION
2.1 Preamble
In 1992, the Radiation Advisory Committee (RAC, or "the Committee") of the U.S.
Environmental Protection Agency (EPA) Science Advisory Board (SAB) decided to undertake as
a self-initiated project a review and analysis of the Committee's activities since its establishment in
FY 85. This review has been carried out by a member and former Chairman of the RAC (Dr.
Oddvar F. Nygaard) with input from some of the other Committee members (in particular, Dr.
June Fabryka-Martin, who provided extensive and valuable editing). During the latter part of
1993, the Executive Committee of the SAB asked each of the standing Committees to prepare a
self-evaluation report to cover its activities. Because the RAC retrospective review at that time
was well underway, the RAC decided that the report of its ongoing effort, and in particular the
last section, would satisfy the request of the Executive Committee.
2.2 Historical Notes on the Radiation Advisory Committee
The SAB was originally established administratively in January, 1974, by the EPA
Administrator. It was recreated in 1978 by the United States Congress as a statutorily mandated
Science Advisory Board. In the first ten years of its existence there was no committee dealing
specifically with radiation within the SAB. During FY 1984 a number of radiation issues emerged
which necessitated the establishment of several ad hoc subcommittees of the Science Advisory
Board, viz., the "High Level Radioactive Waste Disposal Subcommittee," (Chaired by Dr.
Herman E. Collier, Jr.), the "Biological Effects of Radiofrequency Radiation Subcommittee,"
(Chaired by Dr. Charles Siisskind), and the "Subcommittee on Risk Assessment for
Radionuclides," (Chaired by Dr. Roger O. McClellan). These subcommittees all submitted
reports of their reviews during that fiscal year. In anticipation of other radiation issues to be
reviewed, and on the recommendation of the last of the above-listed subcommittees (see later),
the SAB in the latter part of FY 84 decided to establish a standing "Radiation Advisory
Committee." The Committee convened for the first time on February 4, 1985. The charter for
the RAC is included as Appendix C.
2.3 Overview of the Present Report
This review covers the period 1984-1994. There are several practical reasons for selecting
this time frame: by the end of calendar year 1992 all but one of the original RAC members had
rotated off the Committee and the original DFO was transferred to a different SAB committee. It
was felt that this might be an opportune time for taking a backward look and a forward projection
based on the experiences gained from the RAC's activities while some "corporate memory" still
remained.
Appendix A lists the 3 forerunner reports and the 42 RAC reports that are covered in this
review, listed in chronological order. The bulk of the reports relate to reviews of documents
(such as Background Information Documents (BID's) for rulemaking) prepared by or for EPA,
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but several (11) deal with Committee-initiated issues (commentaries and letters). Throughout the
text of this retrospective review, the individual RAC reports are referred to by the sequential
numbers they have been assigned in Appendix A. A list of cross-references between these reports
and the Sections in which they are discussed appears at the end of Appendix A. Appendix B lists
all other non-RAC generated reports that are considered relevant to this review, even though not
all are cited within this report.
For the greater part (Sections 3-8), the reports are reviewed in groups of related subjects
as this allows a perspective regarding the overall issues as well as the developments within an
issue. A number of broader issues and generic opinions expressed by the RAC are outlined and
discussed in Section 9. In Section 10, the Committee attempted to summarize some of its
experiences and indicate steps that could facilitate its performance vis-a-vis the Agency.
In a number of places, reference is made to the Agency's reactions to the RAC's reports,
but this is not done in a consistent manner. However, the Office of Radiation and Indoor Air
(ORIA, formerly the Office of Radiation Programs, ORP), which is the EPA Program Office with
which RAC has had the most frequent interaction, has recently updated its cumulative summary of
its responses to the reports and recommendations submitted by RAC.
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3. ESTIMATING RISKS FROM IONIZING RADIATION
3.1 Risks from Low-LET Radiation
The Radiation Advisory Committee (RAC) on a number of occasions has been asked to
review EPA's risk estimates for ionizing radiations. One reason for the repeated requests is the
continuous development and updating of the risk factors for radiation-induced cancers in humans
resulting from the follow-up in the Life-Span Study of the Japanese populations in Hiroshima and
Nagasaki who were exposed to the atomic bombs in 1945 and the periodic re-evaluations carried
out by various national and international expert committees [e.g., Appendix B reports by the
National Academy of Sciences/National Research Council's (NAS/NRC) committee on Biological
Effects of Ionizing Radiation (BEIR), the International Commission on Radiological Protection
(ICRP), and the United Nations Scientific Committee on the Effects of Atomic Radiation
(UNSCEAR)]. An additional factor has been the revised dosimetry for the atomic bomb
exposures, which significantly altered the calculated doses received by individuals in the two
cities. Finally, as airborne radon became recognized as the greatest source of environmental
radiation exposure, the estimation of risks attributable to radon became a major issue.
The RAC got its first opportunity to review EPA's radiation risk assessment in connection
with the Agency's request for review of its March 13, 1985 Draft Background Information
Document on Low-Level Radioactive Waste Disposal (Appendix A, Report #5). The following
comments relate only to the risk assessment methodology used in this document; for further
review of the document, see another section of this review. A major criticism by the Committee
was that the Agency in many cases failed to draw on the most recent information available and
instead relied too heavily on the National Research Council's 1980 report "The Effects on
Populations of Exposure to Low Levels of Ionizing Radiation: 1980" (Appendix B, BEIR III).
For example, the (January 1985) report by the National Institutes of Health (NIH) Ad Hoc
Working Group to Develop Radioepidemiological Tables (Appendix B, NIH Publ. No. 85-2748)
contained updated estimates of human cancer risks as well as an approach to estimate overall
uncertainty of such estimates. The Committee judged EPA's use of the averages of the values
obtained from the relative and the absolute risk models, which might well produce "conservative"
estimates of cancer risks, to be not preferable to what the Committee considered the "most
probable risk estimate" which seemed to be the absolute risk for leukemia and bone cancer and
the relative risk for the ten significant cancers evaluated by the NIH Working Group. The effect
on the estimated risk coefficients of the ongoing re-evaluation of the Atomic-bomb (A-bomb)
dosimetry had been anticipated by the Agency although there seemed to be some disagreement
about the magnitude of the needed upward adjustments. The Committee further criticized EPA's
treatment of genetic effects which largely depreciated the human evidence in favor of animal data
and the Agency's over-interpretation of the data on teratogenic effects. Overall the document was
judged useful as background for the proposed standards on low-level radioactive waste material;
its heavy emphasis on the dosimetry of internal emitters relative to external radiation was found
not unreasonable in the context of disposal of radioactive waste.
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On reviewing various EPA documents dealing with radiation risk assessment, the RAC
had several times recommended that the Agency adopt the concept of "effective dose
equivalent. " This entity, which had been introduced by the ICRP, is described as the sum over all
tissues of the products of the dose equivalent of the tissue and a tissue-specific weighting factor
which represents the fraction of stochastic risk (cancer and genetic) for that tissue relative to the
total risk for the uniformly irradiated body. The Committee felt that the effective dose
equivalents, rather than the dose equivalents of the specific organs, should be applied as the basis
for regulations dealing with radiation exposure. In a letter to the EPA Administrator (Appendix
A, Report #13), the Committee reiterated its belief and strongly encouraged the Agency to
carefully examine its position on the effective dose equivalent concept, the use of which would
also ensure consistency within the EPA as well as between the Agency and other government,
national, and international committees. [In its response to the RAC the Agency pointed out that
the concept "is most useful in implementation of regulations, but that it is limited and out-of-date
and did not necessarily provide the best current assessment of risk."]
In the early part of 1988 the RAC responded to a request from EPA's Office of Radiation
Programs (ORP) to advise the Agency on the reasonableness of using a range of 120 to 1200
annual fatal cancers (with a nominal central value of 400) per 106 rad as an interim risk estimate
for low-LET total-body irradiation. The Agency at that time was under a court-ordered deadline
for rule-making under the Clean Air Act which would not allow it to wait for the publication of
consensus reports from the National Academy of Sciences (BEIR-V) and the United Nations'
Scientific Committee on the Effects of Atomic Radiation (UNSCEAR), then under preparation.
EPA's proposed risk estimate was based on the estimates provided by the 1980 BEIR-III report
(Appendix B) and the RAC's earlier recommendation (Appendix A, Report #5) that the Agency
adopt the relative risk model for all cancers other than leukemia and bone cancer. The
partitioning of cancers among organs was based on the BEIR-III Tables V-14 and V-15
(Appendix B). The Agency expressed the hope that it would be able to incorporate any new
information that might become available by the time of the final rulemaking.
In its letter report to the EPA Administrator (Appendix A, Report #15), the RAC's Dose
and Risk Subcommittee found the Agency's proposed central estimate and range of risk
acceptable "for the interim" until the anticipated consensus reports became available; in addition
to the already mentioned BEIR-V and UNSCEAR documents, reports by the ICRP and the
National Council on Radiation Protection and Measurement (NCRP) were known to be in
preparation (Appendix B). The Subcommittee expressed the opinion that the effects of new
information and new analyses, such as the recalculation of doses for individuals exposed to the
atomic bomb in Japan, the increased follow-up (especially for individuals exposed as children),
and the changes in the statistical model to the currently more widely accepted relative (or
multiplicative) model, all would increase the estimated level of risk associated with exposure to
low-LET radiation. In view of the additional information that would become available in the near
future, the Subcommittee did not believe that an intensive effort to create an interim model at this
time would be of lasting value to EPA. The Subcommittee also acknowledged that techniques to
evaluate uncertainty inherent in the risk projection lagged behind understanding of its importance
and pointed out that "these uncertainty estimates address only the uncertainties in the existing
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human data and models and not those in estimating environmental sources, transport and human
exposures."
In January, 1992 the issue of cancer risk from ionizing radiation was again put before the
RAC, which was asked to evaluate EPA's revised methodology for estimating radiogenic cancer
risks. The proposed methodology was essentially the Agency's attempt to select the best features
of the different risk estimates that had been prepared by a number of national and international
committees, incorporating the new data that had become available, and in particular the revised
dosimetry and further epidemiological follow-up on the Japanese atomic bomb survivors. The
material presented to the Committee by ORP primarily addressed the risk from low-LET radiation
with only minor reference to the effects of alpha radiation.
At an initial meeting, the Committee orally informed the ORP that its preliminary analysis
was sufficient to guide further work and tentatively accepted ORP's proposal to limit further
consideration to the cancer risk models developed for the Nuclear Regulatory Commission (NRC)
by Ethel Gilbert and for the ICRP by Charles Land and Warren Sinclair (Appendix B). At the
second meeting, ORP described the procedures and risk coefficients it proposed to adopt. These
were primarily derived from the risk coefficients contained in ICRP Publication 60 (released in
1991) which presented two sets of coefficients differing in the model that was used to "transport"
Japanese Atomic-bomb (A-bomb) survivor data to the U.S. population: one was based on the
assumption that excess relative risk would be the same in the two populations regardless of
differences in baseline cancer rates, and the other that the excess absolute risk would be the same
and then extrapolate a constant relative risk forward in time for the US population (this latter
approach was the one used by NIH in its 1985 report on Radioepidemiological Tables). EPA
proposed to adopt the geometric mean of these two sets of estimates for its tissue specific risk
coefficients, with the exception of breast cancer for which it chose the risk coefficient derived by
NRC from the available North American data, thus bypassing the problem of transporting breast
cancer risk estimates across populations. A minimum latent period often years was assumed to
apply for all solid tumors. In the case of individuals exposed under the age of 10, EPA proposed
to use the risks for the age group 10 to 19 years at exposure for which the data were more
numerous and consistent.
In the opinion of the Radiation Advisory Committee (Appendix A, Report #36), the
Agency had considered all major analyses of the Japanese epidemiology as well as other studies of
radiogenic cancer risk, and had presented a thorough and unbiased description of the strengths
and limitations of the various data sets and analyses. Whereas the BEIR-V report (Appendix B)
contained results that might have been given greater consideration, the risk estimates for overall
cancers (upon which most regulations most likely will be based) were relatively constant among
all analyses of the Japanese experience. The Committee recognized the necessity of making
organ-specific risk estimates for situations involving internally deposited radionuclides that are not
distributed uniformly in the body; however, it believed the Agency's documentation should make
it clear that relatively larger uncertainties apply to organ-specific risk estimates than to the
estimated total cancer risk. With regard to the question of assigning a dose rate effectiveness
factor (DREF), epidemiological studies had not produced data in support of a dose rate effect for
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cancers in humans; nevertheless, the Committee agreed that EPA's choice of a DREF of 2 for
low-LET radiation was reasonable as it was consistent with current scientific judgment (cf
Appendix B, ICRP-60 and BEIR-V) and was further supported by the reduced effectiveness of
low-LET radiation at low dose rates in many experimental systems.
As to risk estimation for high-LET radiation, the Committee agreed with EPA's suggested
quality factor for alpha radiation for use with low-LET risk coefficients in situations where
epidemiological data were not available to provide direct risk estimation for alpha radiation
exposure.
The Committee commended the Agency for its intent to calculate cumulative uncertainties
in its estimated risk coefficients because this undertaking was considered crucial to informed use
of the risk estimates. Overall, the Committee judged the recommended methods for estimating
radiogenic cancer risk to be appropriate and supportable in light of current scientific evidence.
3.2 Radon Risk Estimates
In September, 1985, the RAC was asked to review the relative risk coefficient (1.2 to
2.8%) that EPA intended to use for the interim (emergency) assessment of risk for individuals
residing in the Reading Prong (PA) area where high levels of indoor radon concentrations had
been detected. In its letter to the EPA Administrator, the Committee recommended a slightly
wider range for a credible risk estimate than had been suggested by EPA. In response to a follow-
up question, the Committee stated that it was not aware of any evidence that the risks per unit of
exposure for long-term and short-term exposures would be different (Appendix A, Report #6).
Subsequently, the RAC was asked to review the Office of Radiation Program's (ORP's)
proposed radon risk estimates, to be considered for use on part of the revised radionuclides
NESHAP (see later in this report). The Dose and Risk Subcommittee this time took the position
that none of the available models for lifetime cancer risk from radon exposure (Appendix B,
BEIR-IV, ICRP 50, and NCRP report 78) was clearly pre-eminent, and suggested that the
Agency average the results obtained with the BEIR-IV and ICRP 50 models. This averaging
would have the effect of assigning a higher risk to individuals exposed as children and young
adults than would be the case if the BEIR-IV model alone were used (Appendix A, Report #16).
In February, 1990, the Committee was again asked to review the ORP's radon risk
assessment. Because the Agency proposed to use the RAC's suggested approach (involving the
averaging of two models) with some minor modifications, the Committee saw no reason to alter
its prior recommendation other than to suggest that the Agency emphasize the significantly
greater risk to smokers than to non-smokers "to allow smokers to recognize that their overall risk
may be greatly reduced by the combination of cessation of smoking and radon reduction"
(Appendix A, Report #21). In an addendum to the report, the RAC alerted the Agency to the
general lack of data supporting the assignment of a greater risk from radon to individuals exposed
at an early age and recommended that high priority be given to the possible reassessment of that
issue as more information became available.
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During the next year, as the Agency was preparing its "Revised Citizens' Guide to
Radon " (see later), such additional information had appeared when the RAC was asked, in April
1991, to review ORP's "Revised Radon Risk Estimated and Associated Uncertainties." By this
time the preliminary results from EPA's "National Residential Radon Survey " (Appendix A,
Report #11. See also Section 7.4) were available and the NAS/NRC had published its EPA-
sponsored report on "Comparative Dosimetry of Radon in Mines and Homes." On this occasion
the RAC endorsed the sole use of the BEIR-IV (Appendix B) model for estimating overall lung
cancer risk from exposure to radon and recommended that no adjustment be made for individuals
exposed as children and young adults. While this latter point may be considered controversial, the
Committee found no direct support for increased sensitivity to lung cancer from early exposures
to radon; however, it suggested that the possible variation of risk with age might be addressed as
part of EPA's analysis of the uncertainty range around the central estimate of radon-related lung
cancer deaths in the U.S. population. In addition, because the dose-estimate for radon-related
lung cancer is based on a relative risk model, the Committee recommended that EPA review the
changes over time in the underlying lung cancer incidence rate, as well as changes in smoking
habits (Appendix A, Report #25).
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4. NATIONAL EMISSION STANDARDS FOR HAZARDOUS AIR POLLUTANTS
(NESHAP)
In December, 1983, the SAB received a request to review the methodology used by the
Office of Radiation Programs (ORP) in assessing human health risks from airborne releases of
radionuclides. The SAB formed a "Subcommittee on Risk Assessment of Radionuclides" to
carry out the review. The charge to the Subcommittee, as stated by the EPA Administrator, was
(1) "to review the scientific basis of the risk assessments used to develop standards for protection
from radionuclides in the environment," and (2) "to critically review the process by which the
Agency estimates human cancer and genetic risk due to radionuclides in the environment....
[including] examination of the methods used to estimate the transport of radionuclides in the
environment due to emissions into air, the organ doses received by persons inhaling or ingesting
this radioactivity and, finally, the cancer and genetic risks due to these organ doses." A list often
questions prepared by the ORP accompanied the Administrator's request.
The Subcommittee's report (Appendix A, Report #3) was in many ways a seminal one
which went into great detail as to how, in the Subcommittee's opinion, ORP should develop and
present a radiation risk assessment and deal with a number of other issues relating to the
development of environmental radiation protection standards. In addition, the Subcommittee
strongly recommended that a standing committee of the SAB be created to "provide advice on
the full range of scientific activities of ORP's programs," and it even provided the charge for
such a committee, thus becoming the major driving force in the establishment, in 1984, of the
Radiation Advisory Committee (RAC). For these reasons, the Subcommittee's report is given
relatively extensive coverage in this retrospective review.
The Subcommittee's activities can be viewed as addressing two interrelated major
questions. First, did the Agency staff collect the scientifically relevant data and use scientifically
defensible approaches in modeling the transport of radionuclides through the environment from
airborne releases, in calculating the doses received by persons inhaling or ingesting this
radioactivity, and in estimating the potential cancer and genetic risks of the calculated doses?
Second, were the individual facts, calculational operations, scientific judgments and estimates of
uncertainty documented and integrated in a clear and logical manner to provide risk assessment
that could be used as a scientific basis for risk management purposes, i.e., standards setting?
With regard to the first question, the Subcommittee concluded that ORP had generally
gathered the appropriate scientific information in a technically proficient manner for individual
elements of a risk assessment. With regard to the second question, the Subcommittee concluded
that ORP had not assembled and integrated this information in the format of a risk assessment that
provided a scientifically adequate basis for regulatory decisions on airborne radionuclides.
The document that most nearly represented such a risk assessment, but still stopped far
short, was the proposed rule for "National Emissions Standards for Hazardous Air Pollutants:
Standards for Radionuclides," published in the Federal Register [Appendix B, Vol. 48, pp. 15076-
15091, Apr 6, 1983]. By its very nature as a proposed standard, this document included an
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interweaving of scientific facts and interpretation, economic considerations, and social and
political value judgments. A second document, the "Background Information Document:
Proposed Standards for Radionuclides," was a useful supplement to the Federal Register notice.
However, even when the proposed standard and the background document were considered
together, they were neither sufficiently complete nor organized to serve as a scientifically
adequate statement of the health risks from emissions of radionuclides.
For comparison with other scientific activities of the Agency, the Subcommittee referred
to the process used by the EPA in its development of the National Ambient Air Quality Standards
(NAAQS). In that process the Agency had found it appropriate to prepare both a criteria
document and a staff position paper and to obtain reviews by the SAB (specifically the Clean Air
Scientific Advisory Committee, CAS AC) of both documents. The staff position paper served as
an intermediary step between the criteria document and the risk management functions of setting
NAAQS.
The Subcommittee believed that the concept of a staff position paper could be readily
applied to assessing radiation risk and to defining the use of scientific concepts and data in
developing emission standards for radionuclides. Such a staff position paper should include the
conceptual framework for assessing radiation risk, starting with identifying sources of
radionuclide emissions, analyzing the movement of radionuclides from a source through
environmental pathways, calculating doses received by individuals or populations, estimating
genetic and somatic health effects, and presenting a statement of uncertainty in the risk estimates.
This uncertainty should be expressed as central estimates with lower and upper bounds for cancer
and genetic endpoints. These estimates should then be compared to available information on
incidence of cancer and genetic risks in the relevant population. It might also be appropriate for
the position paper or a complementary document to identify various potential levels of a standard,
noting for each level if compliance could be established by direct measurements or only indirectly
by modeling.
In the case of the proposed emissions standards for airborne radionuclides, a staff position
paper was not prepared and the Subcommittee was uncertain as to how and to what extent the
scientific data base was used to set the standard. Also, neither the scientific community in general
nor the SAB was asked to review thoroughly ORP's use of scientific data in early stages of the
radionuclide standards development process.
To improve the scientific basis for regulatory decisions on radiation issues, the
Subcommittee recommended a number of actions, among which were:
(1) "that procedures be established to delineate more clearly the risk assessment and
risk management aspects of the total radiation standards development process,"
(2) "that for each regulatory action considered, the risk assessment process include
development of a risk assessment document that makes reference, as appropriate, to more
detailed analyses found in the scientific literature,"
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(3) "that such a risk assessment document be prepared for airborne radioactivity as a
basis for making any further risk management decisions on the airborne radionuclides
emission standards, including promulgation of final standard(s),"
(4) "that a standing committee be created as a part of the Science Advisory Board to
review risk assessments for radiation standards and to provide advice on the full range of
scientific activities of the Office of Radiation Programs" (emphasis ours),
(5) "that procedures be developed for soliciting and receiving public comments and
SAB review (emphasis ours) of radiation risk assessments before proposed standards are
developed," and
(6) "that steps be taken to enhance communication between the Office of Radiation
Programs and other staff offices of the Agency and the scientific community on issues
relating to risk assessment."
Responses to ORP's list of 10 specific questions were also provided.
The Subcommittee's overall conclusions and recommendations were summarized under
the following four headings:
1) "Need for a Scientific Issues Staff Paper to Identify and Evaluate the Scientific
Basis for Radiation Risk Management Decisions."
2) "Establishment of a Continuous Scientific Oversight Mechanism to Review
Assessments for Radiation Standards and other ORP Activities."
3) "Integration of Risk Assessment Between the Office of Radiation Programs and
Other Staff Offices Within EPA."
4) "Research Needs" - under which were identified: development of air transport
radioactivity models; continuing assessment of the Japanese A-bomb data; determination
of dose-response relationships at low dose rates; validation of radiation doses estimated
with models and subsequent computer codes; the ultimate development of dynamic models
having applicability to specific geographic regions; and development of more sensitive
methods to determine genetic damage.
In 1988, ORP presented to the RAC its plans for revising the technical basis for the
revision of "National Emission Standard for Hazardous Air Pollutants; Standards for
Radionuclides" (Radionuclides NESHAP). This revision was considered an important activity
that could benefit from the use of new data and improved scientific techniques developed in the
previous five to ten years. The RAC formed the "Sources and Transport Subcommittee" to
conduct the review of the NESHAP for Radionuclides Assessment Methodologies. [The Dose
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and Risk Subcommittee of the RAC had earlier in the year prepared reviews of ORP's Low-LET
Risk Estimate for Regulatory Purposes (Appendix A, Report #15) and ORP's Radon Risk
Estimate (Appendix A, Report #16).] The objective of the present review was to examine the
scientific basis for the evaluation of source terms and radiological assessment models that were to
be used in the revisions to the Radionuclides NESHAP Background Information Documents
scheduled for completion in early 1989. Since no formal issues were raised by the Agency in
preparation for the review, the Subcommittee, on its own, identified several topics for discussion.
Of the numerous findings by the Subcommittee (Appendix A, Report #17), three were
highlighted to warrant the most serious attention by the Agency:
1) "Portions of the AIRDOS-EPA methodology are no longer state-of-the-art and
must be updated to incorporate important recent advances in modeling radionuclide
transport through environmental pathways."
2) "To date, EPA's treatment of modeling uncertainties has been qualitative rather
than quantitative although state-of-the-art methods for estimating uncertainty are
available."
3) "Best estimates with appropriate uncertainty statements should be used in all risk
assessments. The best estimate should be statistically defined, according to the target
population or individual, and the shape of the uncertainty distribution."
To correct these deficiencies, the Subcommittee urged the Agency to make use of
qualified groups of individuals to help implement immediate and long-term improvements in
model structures, uncertainty and sensitivity analyses, and model validation. Results from
evaluation of similar radiological assessments were at that time available which the Agency could
use to guide its immediate activities. The Subcommittee recommended longer-term efforts to
substantively upgrade and maintain the Agency's radionuclide transport codes to a state-of-the-art
status.
These concerns aside, the Subcommittee commended the Agency for its intentions to
present radiation consequences as a function of risk level; for the initial steps taken to validate the
atmospheric dispersion code within AIRDOS-EPA; and for the use of simplified models for initial
screening in the case of compliance procedures. With reference to the present review, the
Subcommittee reminded the Agency that very similar findings and recommendations had been
presented to it in SAB's 1984 review (Appendix A, Report #3). The apparent lack of
responsiveness on this matter by the ORP during the 4-year interval was of grave concern to the
SAB. It was the opinion of the Board that some action was required to assure that future reviews
would yield evidence of a more defensible scientific basis for regulatory decisions on radionuclide
emissions.
The Subcommittee expressed the hope that ORP would incorporate the recommendations
of the present review into the Background Information Document (BID) for the Radionuclides
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NESHAP. It also reminded the Agency that the Radiation Advisory Committee had asked for the
opportunity to review Volumes I and II of the new BID when they became available.
On April 26-28, 1989, the RAC met at the request of the ORP to consider the scientific
merits of ORP's BID on the proposed regulatory action on radionuclides in the NESHAP that had
been published in the Federal Register on March 7, 1989 (Appendix B). The Committee
recognized that the document it had seen was not the final version and that, as a result of the
court-mandated constraints under which the rulemaking had to be formulated, the Agency in its
published BID may have anticipated and addressed some of the recommendations offered in the
RAC's report (Appendix A, Report #19).
Overall, the Committee found the estimates of the health risk factors described in the BID
acceptable; however, it expressed reservations about the data and arguments used to derive the
risks and offered several recommendations for the improvement of the document. A series of 17
recommendations were included in the report; special attention was called to three issues that
permeated most of them. These were:
1) the need to use the most current, relevant data available as estimates of the
parameters used in the modeling process,
2) the establishment of a clear demonstration of the objectives of the risk assessment
and the relationship of the BID to the model used to derive the overall risk, the ultimate
basis for the rule-making, and
3) the choice of the estimates of risk used to establish standards and compliance to
those standards.
The following paragraphs enlarge on these items:
1) The RAC had urged ORP on previous occasions to be certain that the data used to
derive its estimates of risk were the most current available and, wherever practicable, to
base its assessments on consensus documents such as those of the United Nations
Scientific Committee on the Effects of Atomic Radiation (UNSCEAR), the National
Academy of Science's Committee on the Biological Effects of Ionizing Radiation (BEIR),
the International Commission on Radiological Protection (ICRP), and the National
Council on Radiation Protection and Measurements (NCRP) (Appendix B). Customarily,
the Office had followed this advice; however, in the present instance, the consensus
document that had been used, BEIR-III, was under revision to acknowledge the
dosimetric changes and the further follow-up that had occurred in the studies of the A-
bomb survivors and of the patients treated with ionizing radiation for ankylosing
spondylitis. This revision would have been available soon; however, a similar
reassessment by the UNSCEAR already existed. The Committee believed strongly that
the credibility of the BID was compromised by its failure to reflect these recent
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developments and that the BID should be revised to incorporate the newer data and their
assessments.
2) It was difficult for the Committee to determine what the actual objectives of the
risk assessment were, and it assumed that if the Committee itself experienced this, the
public and the regulated community would have similar problems. For example, it was not
clear whether the purpose of the risk assessment was to calculate doses and their health
impact on a hypothetical, maximally exposed individual in order to establish a conservative
decision, or to obtain a best estimate of the dose and health implications for a real person
or population. Accordingly, it was recommended that the first chapter of the final BID
state clearly and in detail the overall objectives to be accomplished by the risk assessment,
and that each succeeding chapter culminate in a summary statement on how it related to
the stated objectives of the risk assessment.
3) The Committee recognized that risk assessment is at best a tenuous art, and that
estimates of hazards are commonly dependent on a variety of assumptions, many of which
are of uncertain reality. The RAC and the SAB had repeatedly urged the use of best
estimates and ranges in the specification of risk, and the need to provide a detailed
explanation of the uncertainties in the estimates themselves. It did not appear to the
Committee that this advice had been consistently applied in the BID. Therefore, the
Committee reiterated its recommendation that the Agency develop its overall risk
assessment on the basis of best estimates of all of the parameters involved in the modeling
process, and not merely some, and that it clearly describe the uncertainties and possible
biases inherent in each estimate.
This third recommendation was offered in the context of the risk assessments used to
support the establishment of standards where, in the Committee's view, best estimates should
always be used for all variables in the modeling process. In contrast, determination of compliance
was considered to be a separate matter in which, for the purpose of demonstrating compliance
well below the standard, the use of conservative values in a model would be acceptable.
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5. RADIONUCLIDES IN DRINKING WATER
5.1. Drinking Water Criteria Documents
In January, 1986, EPA's Office of Drinking Water (ODW) requested that the SAB review
a number of scientific issues related to its evaluation of radionuclides in drinking water. The
review was referred to the RAC which formed a "Drinking Water Subcommittee" to fulfill the
charge. Subsequently the SAB received a document entitled "Radionuclides in Drinking Water"
(for publication in the Federal Register) and four "Criteria Documents" on manmade
radionuclides, uranium, radium and radon, in addition to a memorandum that included four issues
for review.
The Subcommittee offered the following comments in response to the four issues raised by
the ODW (Appendix A, Report #9):
It recommended that the ICRP weighting factors (rather than those developed by EPA
based on the BEIR-III report) should be used in calculating the effective dose equivalent because
they were well established, and widely published and used. The ICRP factors had not been
invalidated in any way; furthermore, they included a component for genetic risk.
In reference to uranium, the Subcommittee considered that the radiotoxic health effects
(renal effects) were not sufficiently well substantiated to provide a scientifically credible basis for
regulation; however, uranium should be in category A on a presumed (but not demonstrated)
likelihood of carcinogen!city. The Subcommittee agreed with the non-radiotoxicity health
assessment and concluded that chemical toxicity should constitute the scientific basis used for
regulation. The Subcommittee agreed with the Agency that the dose-response relationship for
naturally occurring alpha particle-emitting radionuclides should be considered to be linear in the
dose range of interest.
Finally, although (at the time) there were no data enabling a clear scientific choice between
relative and absolute risk models for most cancers, the Subcommittee believed that the Agency
should use the absolute risk model for leukemia and bone cancer and the relative risk model for
other sites identified as associated with radiation induction, as recommended earlier in the RAC's
review of low-level radioactive waste disposal (Appendix A, Report #5) in 1985.
The Subcommittee also expressed the opinion that the justifications for the risk estimates
in the documents were not sufficiently documented and that theses values were not consistently
applied. Among technical issues, it proposed that the EPA should consider using performance
specification rather than prescription of specific methods since many available procedures were
equal to, or better than, those presented in the documents. The rationales for the Agency's choice
of certain risk parameters, such as latency periods for some of the tumors of soft tissues and the
quality factor (Q) used with different tissues, were questioned.
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In regard to the risk for radium, the Subcommittee noted that the high risk estimates for
leukemia and soft-tissue cancers relative to bone cancer were contradicted by epidemiological
studies of radium dial painters, among whom only bone cancers and head carcinomas were found
in excess over normal rates.
Finally, the RAC pointed out that radon exposure from water derives from its domestic
uses, not from drinking water. It was felt that this could be emphasized further, possibly by using
the term "drinking and domestic water supplies. "
At the meeting of the RAC in January, 1990, the ODW presented its plans to propose
regulations for radionuclides in drinking water, as directed by the Safe Drinking Water Act
(SOWA). Although ODW was the lead office in this effort, it was assisted by the ORP. The RAC
accepted the request to review the criteria documents and related materials as they became
available, to assess their credibility and correctness, and formed a "Radionuclides in Drinking
Water Subcommittee" to conduct the review. During the course of the review the following
documents were received:
Drinking Water Criteria Document for Uranium, draft dated November, 1989;
External Review Draft for the Quantification of Toxicological Effects Document on
Radium, draft dated July 10, 1990;
Quantitative Risk Assessment for Radon in Drinking Water, draft dated May, 1990;
Quantitative Risk Assessment for Beta Particle and Gamma Emitters in Drinking Water,
draft dated May, 1990; and
several papers relating to ingestion of radon-222 and transfer of radon from drinking
water to indoor air.
The ODW posed five specific questions to the Committee on uranium metabolism, risk
from ingested radon, the basis for estimating the risks from radon in water, the use of
epidemiological data and modeled risk estimates in evaluating radium risks, and methodology for
risks from man-made radionuclides.
The Subcommittee returned a very critical review of the drinking water document
(Appendix A, Report # 26), as reflected in the following extensive excerpts of the report:
"The overall quality of the four draft criteria documents was not good. Taken as a
set, the documents are inconsistent in approach and with Agency practice in the derivation
of drinking water criteria such as those for volatile organic contaminants. The
Subcommittee found that recommendations from a 1987 Science Advisory Board report
on its review on the basis for standards for radionuclides in drinking water (Appendix A,
Report # 9) had not been addressed. Nor did the new criteria documents address
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recommendations from other available SAB reports that are directly relevant (such as
Appendix A, Report #13 and the resolution on use of mathematical models (Appendix B,
EPA-SAB-EEC-89-012). Technical decisions contrary to those recommended by the
SAB were presented without justification and with acknowledgment of the existence of
the SAB recommended alternatives. Relevant recommendations of the National Research
Council's Committee on the Biological Effects of Ionizing Radiation [Appendix B, BEIR-
UT] were ignored or selectively adopted without explanation or rationale. Uncertainties
associated with the selection of particular models, specific parameters used in the models,
and the final risk estimates are not adequately addressed in any of the documents."
The following quotes from the cover letter to the EPA Administrator represent the
Subcommittee's responses to the ODW's specific questions.
a) "The estimates of the absorption, distribution, and excretion of uranium when
ingested are not appropriate or supported by the data. The basis for the metabolic model
chosen and the value of the gut-to-blood absorption factor (fj) have not been adequately
discussed. Furthermore, the chosen value of fj appears to have been arbitrarily selected
from among the highest of all reported values. The uncertainties associated with
parameter and model selections are not discussed."
b) "The methods employed in the radon document do not form an appropriate basis
for assessing the risks of directly ingesting water containing radon. The assumption of a
tap water consumption rate of 0.66 liters per day conflicts with other Agency practice as
does the assumption of a 20% volatilization loss between the tap and container. The basis
for and uncertainty associated with the assumed values are not adequately addressed."
c) "The appropriate basis for estimating risks from radon in water requires that both
the direct (ingestion) and indirect (inhalation) exposure routes be carefully assessed. The
EPA draft document treats both pathways; however, possible inhalation exposures to high
concentrations at the point of use have not been addressed. Assessment of uncertainties is
an essential component of the evaluation of both pathways. The risk estimate for
exposure to airborne radon presented in the document disagrees with an Agency position
paper previously submitted to the SAB for review (SAB-RAC-LTR-91-001)" [Appendix
A, Report #21].
d) "For radium, the available human epidemiologic data should most definitely be
used to determine risk, rather than a mathematical model. This recommendation reaffirms
the previous response (SAB-RAC-87-035)" [Appendix A, Report #9].
e) "The methodology for assessing risk from man-made radionuclides (both
individually and collectively) is incomplete, because there is not a criteria document for
man-made alpha emitters. The draft document employs a set of ad hoc risk factors that
have not been reviewed. Instead of providing the basis for selection of a guide value, the
level of 4 millirem per year was assumed. The document does not employ the effective
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dose equivalent concept and does not adequately address uncertainty in the input
nflrameters and risk estimates "
A A
parameters and risk estimates."
The Subcommittee was troubled by the Agency's failure to address the SAB's earlier
comments and recommendations, as well as relevant recommendations contained in the BEIR-IV
and BEIR-V reports (Appendix B). The EPA 1990 documents reflected technical decisions
contrary to those specifically recommended by the SAB, selectively adopted material from other
technical consensus reports, and presented decisions concerning the risks of radionuclides in
drinking water without justification or acknowledgment. Given this pattern, particularly the
inattention to uncertainties and previous BEIR Committee and SAB recommendations, the
Subcommittee found it difficult to understand the scientific basis for the selection of maximum
contaminant levels.
In January, 1992, the RAC submitted a self-initiated Commentary to the EPA
Administrator (Appendix A, Report #30) dealing with two issues that had come up as the result of
the earlier reviews of ODW's drinking water documents (Appendix A, Reports #9 and #26),
already discussed above. The purpose of the Commentary was two-fold: (1) to address the
fragmented and inconsistent approach regarding reduction of radon risk, and (2) to provide
closing comments on the revised drinking water criteria documents supporting the proposed
regulations.
5.2. Proposed Drinking Water Regulation in Relation to "Reducing Risk" Report
In this part of its Commentary, the Committee acknowledged that technical aspects are
only one (Appendix A, Report #30) of many factors that must be considered in making policy
determinations. However, the Committee decided to express its view on the relative risks
addressed by the proposed regulations vis-a-vis other radon risks reviewed by the Committee and
to offer its views on the implications of its technical observations for matters of policy.
The ODW, after considerable deliberation, had proposed to regulate radon in drinking
water in the manner adopted for other contaminants under the SDWA, that is, at an approximate
lifetime risk level of 10"4. The chief risk from radon in water is its release into the air and
subsequent inhalation, as opposed to ingestion of waterborne radon. Thus a 10"4 risk level
(averaged over smokers and non-smokers) translates into about 0.03 pCi/L in air, or
approximately 300 pCi/L in water. That air concentration is more than 100 times smaller than the
Agency's voluntary guideline of 4 pCi/L for radon concentration in indoor air. It is also well
within the natural year-to-year variation in indoor radon concentrations in average houses.
Congress, as part of the Indoor Radon Abatement Act, defined the goal of achieving an indoor
radon level equal to the natural outdoor level, which is 0.1-0.5 pCi/L, depending on the area of
the country. This goal is a factor of 8-40 below the indoor action level, but a factor of 10 higher
than the indoor radon level corresponding to the proposed regulation for radon in drinking water.
The Agency estimated that about 5% of the total indoor radon in homes served by ground
water would be due to radon released from household water use. Data in the radon criteria
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document indicated that approximately 10-30% of the population relying on ground water
sources was exposed to water with radon concentrations above the proposed maximum
contaminant level of 300 pCi/L. Overall, about 1% of the total indoor radon in areas dependent
upon ground water supplies would be addressed by adopting the proposed regulation.
The Committee concluded that the radon exposure situation reflected the fragmentation of
environmental policy as identified in the SAB's "Reducing Risk" report (Appendix B, EPA-SAB-
EC-90-021). The tactics and goals of different laws designed to address radon exposures have
clearly not been consistent, and efforts within the Agency to reduce radon risk, while not
uncoordinated, were rooted in programmatic areas that responded to different laws.
In harmony with Recommendation 4 of "Reducing Risk, "
a) "EPA should reflect risk-based priorities in its strategic planning processes. The
Agency's long-range plans should be driven not so much by past risk reduction efforts or
by existing programmatic structures, but by ongoing assessments of remaining
environmental risks, the explicit comparison of those risks, and the analysis of
opportunities available for reducing risks."
Analyses have shown radon in drinking water to be a very small contributor to radon risk
except in rare cases, and the Committee therefore suggested that the Agency focus its efforts on
primary rather than secondary sources of risk. The RAC recommended that the Agency conduct
a full media-based risk assessment of the various options for regulating radon in drinking water.
Such an evaluation should also include the risk posed by the treatment or disposal of any wastes
produced by water treatment.
5.3. Closing Comments on Revised Drinking Water Criteria Documents
Following the Committee's review of the second set of draft documents in the summer of
1990, the ODW, with the assistance of the ORP, revised the criteria documents supporting the
proposed regulation. The Committee decided not to undertake a formal review of the third set of
criteria documents, however, since the fundamental scientific questions had been discussed in its
previous reviews, cited above. The Committee chose to stand by its original positions and
believed that the Agency could further improve the scientific credibility of the criteria documents
by adopting its recommendations (Appendix A, Report #30). The new set of documents were
found to be more complete and individual reports now included more explanations of the options
considered, selection criteria, and possible alternative choices. The Agency had been less
successful in implementing the Committee's advice on uncertainty analysis; although each revised
criteria document included a chapter discussing uncertainty, the contents of those chapters were
found to be very qualitative and not the rigorous technical analysis envisioned by the Committee.
Overall document quality and clarity were still judged inadequate for reports that were intended to
be the technical bulwark for Agency decisions.
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The Committee proposed that broad scope assessments, of the type recommended above
for radon, were also needed for other of the proposed regulations. It further believed that the
Agency's analyses should also include the risks resulting from the concentration of radium,
uranium, and other radionuclides in wastes resulting from water treatment. These risks included
those to workers involved in disposal activities as well as those of disposal itself.
5.4. Drinking Water Treatment Wastes Containing NORM
In the wake of reviewing the ODW's drinking water criteria documents, the RAC
reviewed the Agency's "Suggested Guidelines for the Disposal of Drinking Water Treatment
Wastes Containing Naturally-Occurring Radionuclides, " a document dated July, 1990. Staff
from both the Office of Drinking Water and the Office of Radiation Programs briefed the
Committee at its public meeting in May, 1992: the Committee's report (Appendix A, Report #35)
was submitted in September of the same year.
In developing these guidelines, the ODW had clearly recognized the potential magnitude
of this source of exposure. The Committee applauded the ODW's initiative but found that the
guidelines document lacked information needed to fully assess the magnitude of risk from
exposure to radioactivity in drinking water treatment wastes. (Such a risk assessment was also
missing from the regulations proposed in 1991: the need for such an assessment was cited by the
Committee in its drinking water Commentary (Appendix A, Report #30). Another important
shortcoming was the failure to specify whether the radiation exposure to water treatment plant
workers should be considered as occupational exposures or be viewed against the dose limits for
the general public. This decision would have considerable bearing on any final guidelines.
However, the Committee commended ODW staff for recognizing that public water supply
operators would need guidance both about the management and disposal of the drinking water
waste residues and about the protection of treatment plant workers. It appeared to the
Committee that the staff had recognized the very important issue of "risk-risk analysis" (i.e.,
considering the net effect of eliminating or reducing a risk by introducing an action that by itself
carries a risk) before this concept was prominently discussed by various committees of the SAB.
The Committee recommended that the Agency revise and strengthen the "Guidelines" by
obtaining additional data and by clarifying both the scientific rationale and the policy decisions
underlying many of the recommendations. The 1990 "Guidelines" document was found to include
all the relevant treatment technologies but, because the discussion of these and of the waste
disposal practices was highly qualitative, the document was not sufficient by itself for making
scientific, engineering or economic choices. As for the recommended radiation exposure
guidance for workers, it was unclear to the Committee whether the suggested external gamma-
radiation exposure guide was based on a policy of As Low As Reasonably Achievable (ALARA)
or on an apportionment of the widely accepted guidance of a maximal acceptable dose of 100
millirem per year for the general population. The Guidelines conclusion that "an occupational
exposure level of 25 mrem/year for external and committed effective dose equivalent at water
treatment plants" was not supported; furthermore, the Agency should evaluate the feasibility of
measuring exposure rates that would produce 25 millirem per year. While there are both public
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and work-related exposure issues associated with water treatment plant operation and waste
handling and disposal, the Agency had not estimated the risk to either group, nor compared them
with the risk reduction estimated to accrue from radionuclide removal from water. Although this
comparison would not be an entirely straightforward process, an overall risk/benefit perspective
would have been useful.
5.5. Chafee-Lautenberg Amendments
In November and December, 1992, the RAC, together with SAB's Drinking Water
Committee (DWC), consulted with staff of the Office of Water and the Office of Radiation and
Indoor Air (ORIA) on EPA's outline for a Congressionally mandated multi-media risk assessment
for radon developed in response to the so-called "Chafee-LautenbergAmendments" (Appendix B,
Public Law 102-389) to the Agency's FY 93 Appropriation Act. This consultation took place
during a series of four publicly announced conference call meetings (Appendix A, Report #37).
The Committee as well as EPA staff found this consultation to be very valuable and mutually
useful, and a number of important issues were raised that the Agency subsequently considered in
developing its risk assessment.
The review of EPA's resulting document, "Uncertainty Analysis of Risks Associated with
Exposure to Radon in Drinking Water"., and related documents and public comments took place
in February, 1993. In the document the Agency responded to Congress' directive to "conduct a
risk assessment of radon considering .... the risk of adverse human health effects associated with
exposure to various pathways of radon .... Such an evaluation should consider the risks posed by
the treatment and disposal of any wastes produced by water treatment." Congress also required
that "The Science Advisory Board shall review the Agency's study and submit a recommendation
to the Administrator on its findings." The EPA's uncertainty analysis addressed four radon
exposure pathways: inhalation of indoor radon from non-water sources, inhalation of radon
outdoors, ingestion of waterborne radon, and inhalation of waterborne radon. The charge to the
RAC was to review the adequacy of revisions of ingestion and inhalation risk from radon progeny
and the adequacy of uncertainty analysis regarding risk assessment of waterborne radon, including
health risk analysis and exposure analysis.
In its review of the Agency's document (Appendix A, Report #40), the Committee
commended the EPA staff for having produced an excellent document that responded to previous
SAB comments on uncertainty analysis and the exposure to radon gas at the point of use (e.g.,
showering). The EPA's response was all the more impressive given the constraint of tight
deadlines imposed upon it by Congressional and Court mandates. Its quantitative analysis of
uncertainties in the radon risk assessment represented a methodology that was essentially state-of-
the-art. The Committee assumed that this reflected the EPA's recently stated commitment to a
more rigorous approach to evaluating uncertainties in its risk analysis of radiological and other
hazardous exposures in the future.
The revised estimates for ingestion and inhalation risks from radon in drinking water
indicated that the risk from ingestion was approximately one-half of the risk from inhalation, and
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both risks are considered scientifically acceptable. There was concern, however, that the
uncertainties in the estimates of the ingestion risk could be larger than suggested by the
quantitative uncertainty analysis. The Committee recommended that the EPA incorporate a
qualitative discussion of known, but not quantified, uncertainties in its analysis and, given the
larger uncertainty bounds associated with the ingestion risk, that consideration be given to
keeping the ingestion and inhalation estimates separate in the Agency's deliberations on standards
for radon in drinking water. The Committee also reiterated its previously stated concerns that the
overall risk associated with radon in drinking water was small compared with the average radon
exposures due to indoor air and that the drinking water risks be viewed in context with other
radon risks in the summary documents developed by EPA.
In addition, the Committee provided comments and recommendations regarding the
adequacy of the analysis and the approaches taken. Among these was the recommendation that
EPA look at a range of water treatment technologies and include in the analyses risks from
occupational radiation exposures and potential waste disposal issues. Finally, the Committee
recommended that particular attention also be given to the uncertainties associated with the
variance and shape of the probability density functions used by EPA to represent variability of
exposures among individuals.
This review by the RAC constituted a part of a broader SAB assignment, and the above
RAC report was attached to a report to the EPA Administrator from the SAB Executive
Committee, entitled "SAB Review of Multimedia Risk and Cost Assessment of Radon in Drinking
Water" (Appendix B, Report EPA-SAB-EC-LTR-93-010).
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6. RADIOACTIVITY MANAGEMENT AND WASTE DISPOSAL
6.1 Idaho Radionuclide Exposure Study
In September, 1986, the ORP asked the RAC to review the work plan for the Agency's
proposed study to assess the total integrated risk to the communities of Pocatello and Soda
Springs, Idaho, from all radioactive emissions into the air and water and from the use of solid
waste resulting from the nearby phosphorus industries. In describing the need for this study, the
Agency pointed out that phosphorus ore contains approximately 60 times the levels of natural
radioactivity normally found in the earth's crust; some of the radioactivity is released to air and
water during processing of the ore, and some is distributed in the environment through the use of
solid wastes. Besides stockpiles of slag, phosphogypsum, and phosphate ore at the phosphate
fertilizer plants, slag containing elevated concentrations of naturally occurring radionuclides had
been used as an aggregate material for paving and building throughout the communities. The
original work plan was subsequently revised and the final document was sent to the Committee in
March, 1987 and was reviewed at the June, 1987 RAC meeting.
The revised objective of the study was more limited than the original one, viz., "to
determine the magnitude and relative importance of the various industrial sources of radiation and
to estimate the dose to the populations of Soda Spring and Pocatello from these sources." The
Committee found (Appendix A, Report #10) that the revised version of the study plan was of
sufficient quality and detail to achieve the study's objective. This conclusion resulted primarily
from changes made in approaches to sampling and measurements of radionuclides, enhanced use
of existing data, and improved use of meteorological information.
The Committee made two additional comments, neither of which was felt to affect the
ability of the proposed plan to achieve its objective:
(1) In the absence of information on indoor/outdoor polonium-210 ratios, the Agency
in its March, 1987 transmittal memo stated that it would assume the indoor polonium-210
concentration to be the same as the outdoor concentration and that this assumption would
result in a conservative estimate of dose. However, this assumption could also be
incorrect. A better approach would have been to take a conservative indoor/outdoor ratio
based on literature values, rather than to assume a ratio of unity.
(2) The Committee expressed the hope that, in the final report of the study, lung doses
resulting from inhalation would be converted into effective dose equivalents so as to
permit these doses to be added to the external doses from gamma radiation originating in
slag. Because these two pathways were expected to be the principal modes of exposure,
the Committee felt it to be important that they be expressed in comparable units.
In January, 1991, EPA asked the RAC to review the results of the completed
Idaho Radionuclide Study. This study was originally designed to support the rulemaking
on the radionuclide NESHAP, not for an explicit evaluation or remediation of individual
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radiation exposures. However, the study did provide radiation exposure data that
prompted the Agency's consideration of current and past uses of phosphorus slag. The
matter was brought back to the SAB for a timely review to resolve the issues involved
with slag reuse, because members of the general public could come in contact with the
gamma radiation fields associated with the slag. The Agency's actions in this case had the
potential to set important precedents for sites with residual radioactivity and/or elevated
exposure rates resulting from past technological activities. In its report (Appendix A,
Report #28) the Committee addressed the four questions asked by the Agency, to which it
added its comments on the broader technical and policy concerns.
(1) Was the "Idaho Radionuclide Study" implemented consistent with the SAB's review of
the study design?
Most of the components were implemented, with three exceptions: (a) Measurements
were made in homes volunteered for participation in the study rather than in a
representative random sample in each sector; this could potentially introduce a selection
bias, (b) An actual indoor/outdoor polonium-210 ratio could not be established as
planned, which may result in overestimation of lung dose; however, this was not viewed as
significant since the primary radiation doses are principally from direct gamma exposure.
(c) Indoor radon measurement data were not presented but, because the radon emanation
rate from glassy phosphate slag was found to be small, the absence of these data was not
viewed as significant.
(2) Were the study's exposure scenarios for "average" and "maximally exposed"
individuals reasonable?
The gamma radiation exposure scenario for the "maximally exposed individual" was for a
hypothetical person and it is highly unlikely that a single individual would be exposed to
the maximum exposure rate in the home, workplace, and public sectors. The "average"
exposure scenario incorporated a number of reasonable assumptions but, due to the
limited number of indoor measurements, the non-random nature of home selection, and
the uncertainties in exposure conditions based on aerial surveys, the calculated population
dose was considered unreliable; furthermore, decisions on specific actions would require
data on individual exposures.
(3) Are the results of the study sufficient to make reasonable estimates of the population
radiation exposure due to slag?
No, because the study could not identify those members of the population receiving the
highest exposures or quantify those exposures that may occur at various exposure ranges
above background. The study did demonstrate (based on actual exposure rates measured
in homes and on the ground) that elevated gamma radiation levels occurred in Pocatello
and Soda Springs such that some persons could receive doses above 100 millirem per year
in excess of natural background but did not provide the necessary data on which to base
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potential regulatory initiatives or remedial actions for individuals exposed to elevated
radiation levels.
The Committee further recommended that the Agency prepare a plan for obtaining reliable
exposure determinations and provide it for technical review. The study plan should
contain, at a minimum, means for determining reference background for each area, and
means to determine dose rates and accumulated doses from various areas, especially
residences.
(4) Were the cancer risk factors used in estimating potential health effect appropriate?
The Committee here referred to its earlier recommendation (Appendix A, Report #15) as
to models to be used to estimate cancer risk but made the following concluding statement:
"Although the study design did not suggest that risk determination would be made with
the exposure data, such estimates were in fact made. Because the population dose
estimate is flawed, the calculated risk estimates are not meaningful and [are] of little value
as a basis for future actions."
In a closing section the Committee called attention to the considerable interest of the
Idaho citizens, industry, and other members of the public in the Agency's deliberations on this
issue, especially as they might affect potential disruption in people's lives, costs, and risks involved
in actions for phosphorus slag. In the words of the Committee, "The Idaho Radionuclide Study
was not designed to and does not provide a sufficient basis for removal or remediation actions. A
much more detailed study would be required before such actions can be considered." The
Committee went on to suggest that the Agency establish a set of graded decision guidelines based
upon technical and economic factors for both short-term and long-term exposure of the public
due to past uses of slag, and make them available for public and SAB review; it further suggested
that past and current slag uses be considered separately, because the cost/risk considerations
involved make them distinctly different technical issues for assessment and control, including
selection of any action level.
As a final opinion the Committee made the following statement: "Numerous other
situations exist where actual and potential exposure to residual radioactive substances may occur
at similar levels and risks; therefore, the Committee urges the Agency to take the necessary steps
to develop an overall policy for addressing situations of this type."
6.2. Residual Radioactivity
Simultaneous with its 1991 review of the Idaho Radionuclide Study the RAC prepared a
self-initiated Commentary to the Administrator (Appendix A, Report #24) urging the Agency to
develop Federal radiation protection guidance specially for removal or remediation actions for
radioactive substances at various locations, including Superfund sites and Federal facilities. No
radiation guidance directed to allowable residual radioactivity contamination at such sites then
existed. The Committee's recommendation was directed toward residual radioactivity resulting
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from human activities, not from naturally occurring distributions of radionuclides. The guidelines
available for assessing cancer risk focused mainly on chemical contamination at Superfund sites.
Both the Department of Energy (DOE) and the Superfund program must deal with
radioactive contaminants at more than a hundred sites of various types. The number has increased
as Federal site evaluations proceed, and as radioactivity sources not previously considered gain
public attention. The Congress had recognized this potential problem by directing the Agency to
address this issue in a recent appropriation bill. The Agency had issued an Advance Notice of
Proposed Rule-Making for residual radioactivity in 1986 but as of 1991 had made little progress
in finalizing this notice.
The Committee's Commentary contained a list of technical issues to be considered in
developing guidance. Such guidance could include residual contamination levels for individual
radionuclides that should not be exceeded, or could perhaps set forth decision-making processes
for establishing such levels. Superfund guidance suggested that any lifetime risk in excess of one
in ten thousands was an obligatory (de maximus) basis for consideration of the feasibility of
removal or remediation action. Once an action had begun, the risk goal could be as low as one in
a million, representing a de minimis level for which no further action was indicated. From the
RAC's perspective, the Agency needed to establish whether the de maximus and de minimis values
used for Superfund actions for chemicals were justified for radionuclides as well and, if it were
determined that these levels were not justified, such values and Applicable Relevant and
Appropriate Requirements (ARAR) for radionuclides had to be established.
In October, 1992 the RAC met with ORIA staff to consult on the technical approach to
radiation site cleanup regulations (Appendix A, Report #42). The staff gave a brief overview of
EPA's technical support for development of cleanup regulations for radioactively contaminated
soils, aquifers, and buildings. The SAB recognized the importance of EPA's role in setting these
regulations, as decontamination and decommissioning of military bases and nuclear facilities were
getting underway and were expected to be a major cleanup problem for the next several decades.
The ORIA staff provided brief discussions on EPA's approach to the cleanup of
radioactively-contaminated sites covering a number of topical areas such as site categorization,
Agency data and reference sites, various information sources, pathway models, cost assessment,
individual, worker, and population risk assessments, cleanup and disposal costs, and a sensitivity
analysis of a number of variables. At the time of writing of this retrospective review, the RAC
was involved in follow-up interactions on technical aspects of the cleanup standards, including the
scheduled review of draft documents.
6.3. Naturally Occurring Radioactive Materials (NORM)
At the request of the Office of Radiation and Indoor Air (ORIA, the successor of ORP),
the RAC reviewed the Agency's May 1993 draft document "Diffuse NORM - Waste
Characterization and Preliminary Risk Assessment." In its review (Appendix A, Report #44) the
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Committee responded to six specific questions asked by the Agency and also provided a number
of general comments and suggestions.
The NORM document was the latest draft in a series spanning several years and reflected
the responsiveness of ORIA to comments by EPA internal reviewers, by the public, and by RAC.
The Agency appeared to have accessed and summarized most of the information about diffuse
NORM that was generally available at the time the document was prepared. However, in the
opinion of the RAC, the document did not meet its stated goal of providing a scoping analysis of
the NORM problem sufficient to determine the need for additional investigations or for regulatory
initiatives.
In response to the six specific questions in the charge, the Committee provided the
following findings:
1) "The NORM document does not adequately convey the deficiencies and
uncertainties in the information available to characterize the sources of NORM. The
choices of nominal values for volume and concentration used in the risk assessment are
not sufficiently justified. Some values appear to be overestimates (especially for
concentrations) while others appear to be underestimates."
2) "The justification provided for parameter values used in the risk assessment is not
sufficient. In addition, the NORM document uses aggregate factors for food uptake and
dose conversion that incorporate many other assumptions and parameter choices, making
evaluation difficult. The RAC suspects that the food uptake factors may tend to
underestimate exposures."
3) "With few exceptions , the NORM document has selected reasonable
scenarios and pathways of exposure for analysis."
4) "The NORM document has used appropriate models for the most part. The RAC
notes, however, that advective flow was not considered in the model for radon exposures,
and suspects that this omission may have led to underestimates of exposures for radium in
the waste."
5) "While the greatest uncertainties are in the estimates of risks from pathways that
probably do not contribute much to total risk, the risks from specific sources are probably
not known within a factor of three, despite what might be inferred from the language in
the NORM document."
6) "The RAC believes that if the EPA addressed the deficiencies identified in this
review, the revised document could serve as a useful compilation of information for the
public on NORM source terms and potential exposure pathways. However, to go beyond
this limited use and to meet the goal of serving as a screening tool for identifying those
categories that may require regulatory attention, it would be necessary for the Agency to
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conduct its risk assessment analysis using a consistent approach in addressing
uncertainties, such as the methodology suggested by RAC in its report."
The Committee believed that, in spite of its shortcomings, the NORM document
nonetheless provided indications that some categories of NORM might produce risks that exceed
those of concern from other sources of radiation. Consequently, the RAC was of the opinion that
the issue of NORM deserved substantial attention within EPA, and was concerned that resolution
of this issue would require an increased commitment of resources. The RAC pointed out the need
for the Agency to distinguish between those categories of NORM that may be rated high with
respect to individual risk and those that may be rated high with respect to population risk.
6.4. High-Level Radioactive Waste Disposal
In January, 1983 [before the establishment of the Radiation Advisory Committee], the
SAB was asked to review EPA's proposed environmental standards for the management and
disposal of spent nuclear fuel, high-level and transuranic radioactive wastes (40 CFR 191). A
High-Level Radioactive Waste Disposal Subcommittee was formed to review the technical basis
of the proposed standards.
In its report (Appendix A, Report #1) the Subcommittee accepted the general form of the
proposed standards but recommended several changes in the standards as well as improvements in
the supporting methodology. The principal recommendations are highlighted in the following
text.
a) The Standard:
1) "The Subcommittee recommends that the release limits specified in Table 2 of the
proposed standards be increased by a factor often, thereby causing a related ten fold
relaxation of the proposed societal objective (population risk of cancer)."
The Subcommittee noted that the proposed release limits were directly related to
the societal objective of not exceeding 1,000 deaths in 10,000 years, and thus, compliance
with this recommendation carries with it a related ten fold increase in the societal
objective. The relaxation in the release limits was, in the Subcommittee's opinion, justified
for the following reasons. First, the proposed release limits in Table 2, and therefore the
proposed societal objective, were considerably more stringent than those standards
generally required or adopted in today's society. Second, in addition to the fact that some
of the cancer deaths which might result from these releases were calculated using
conservative assumptions that probably overestimated the number, some of these deaths
would have resulted at least in part from the unmined ore from which the wastes were
subsequently generated, and thus were substitutional rather than additional in nature.
Third, the Subcommittee believed that the compounding of conservatism by EPA in the
choice of probabilities and specific model parameters used throughout the analysis was not
warranted.
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b) Uncertainty and the Standard:
1) "We recommend that the probabilistic release criteria in the draft standard be
modified to read 'analysis of repository performance shall demonstrate that there is less
than a 50% chance of exceeding the Table 2 limits, modified as is appropriate. Events
whose median frequency is less than one in one-thousand in 10,000 years need not be
considered'."
2) "We recommend that the use of a quantitative probabilistic condition on the
modified Table 2 release limits be made dependent on EPA's ability to provide convincing
evidence that such a condition is practical to meet and will not lead to serious
impediments, legal or otherwise, to the licensing of high-level-waste geologic repositories.
If such evidence cannot be provided, we recommend that EPA adopt qualitative criteria,
such as those suggested by the NRC."
c) The Time Frame - 10,000 Years and Beyond:
1) "We recommend that EPA retain the 10,000-year time period as the basis for
determining the adequacy of repository performance. We believe that the use of formal
numerical criteria limited to this approximate time period is a scientifically acceptable
regulatory approach."
2) "We recommend that the process of selection of sites for disposal systems also
take into account potential releases of radioactivity somewhat beyond 10,000 years.
Particular attention should be focused on potential releases of long-lived alpha-emitting
radionuclides and their decay products."
This recommendation recognized that the potential for radionuclide releases would
not stop after 10,000 years, but could continue in amounts equal to or exceeding those
estimated for the initial period. The degree of confidence with which impacts could be
modeled much further in the future was much less certain. The Subcommittee did not
recommend detailed modeling calculations regarding post-10,000 year releases, but
believed that estimates should be made, and should be considered as factors in disposal
site selection.
d) Population vs. Individual Risk
1) "We recommend that EPA retain the use of a population risk criterion as the measure
of performance for the proposed standards."
The Subcommittee found that an approach employing individual dose limits, i.e.,
considering some "maximally exposed individual" or alternatively some "average
exposed individual" would, in practice, make the standard difficult to meet with high
assurance for very long times, and that use of a population risk approach would be more
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practical. In its view, however, it is important that for the first several hundred years
residents of the region surrounding a repository have a very great assurance that they will
suffer no, or negligible, ill effects from the repository. For longer periods, the
Subcommittee believed that EPA should rely on the existence of continuing requirements
similar to its current [1983] drinking water standards to protect groups of individuals.
e) Coordination of Policies and Standards:
1) "We recommend that EPA initiate action within the Federal Government for the
establishment of an interagency council to coordinate the development of high-level
radioactive waste disposal policy, standards and regulatory practices and to serve as a
forum for exchange of scientific and technological information."
Several Federal agencies are involved in the process of establishing radiation
protection policies, standards and operational requirements governing the disposal of high-
level radioactive wastes, including EPA, NRC, DOE and DOD, together with states,
appropriate entities of Congress and the judiciary. Overlapping and independent
authorities and responsibilities exist under the present law. Coordination of Federal
policies and practices is essential to the U.S. high-level radioactive waste disposal
program. While the lead in coordination could be appropriate for the NRC or DOE, the
Subcommittee feels that the obligation for achieving mutual interaction more appropriately
belongs to EPA under its authority to issue environmental standards and Federal Radiation
Protection Guidance.
f) Research Needs - A Matter of Priority:
1) "We recommend that EPA support, or encourage other agencies to support,
continuing research in technical areas where major uncertainties still exist, particularly in
the biological effects of radiation, the geochemical transport of radionuclides, and the
characterization of rock-mass deformation."
6.5 Release of Carbon-14 in Gaseous Form from High-Level Waste
In 1987 a Federal Court remanded portions of the standards for disposal of high-level
waste, spent fuel, and transuranic waste promulgated by the EPA in 1985 (see above). To satisfy
the Court's ruling, EPA was required to revise and update the standard. The earlier analysis did
not consider the potential for gaseous releases from high-level waste disposal (except as a
consequence of volcanic eruptions), but it was not certain whether or not unsaturated sites could
comply with the earlier standard with respect to releases of carbon-14. At the request of the
ORP, the RAC in 1992 established the "High-Level Waste / Carbon-14 Subcommittee" to review
the Agency's document entitled "Issues Associated with Gaseous Releases of Radionuclides for a
Repository in the Unsaturated Zone." The summary that follows represents selected excerpts
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from the Subcommittee's cover letter accompanying its report (Appendix A, Report #39) and
contains its most significant findings and recommendations.
a) "Releases of carbon-14 from a repository may produce an appreciable global
population dose over 10,000 years, but the average individual dose would be very low.
For a reasonable upper bound release of half the carbon-14 originally contained in a
repository, the global population dose over 10,000 years is estimated to be 14 million
person rem, and the corresponding average individual lifetime dose would be about 0.01
mrem. Based on the EPA's preliminary risk factor for carbon-14, these doses correspond
to calculated lifetime individual risks of 3 x 10"9, and population risks of less than one
fatality every two years on average, or 4,000 cancer fatalities world wide over 10,000
years. Whether or not these doses constitute a public health concern is a fundamental
issue of principle. The Subcommittee did not try to resolve this issue, but EPA must
address it when considering carbon-14 releases. Consistent with the report "Reducing
Risk" (Appendix B, EPA-SAB-EC-90-021), the Subcommittee recommends the predicted
individual and population doses be considered in comparison with doses from other
sources, with dose limits in other standards, and with other environmental and radiation
risks.
b) "The uncertainty analysis performed in the issues document is in a preliminary state
and can be improved substantially. ... [It] is not possible on the basis of presently
available information to predict with reasonable confidence whether releases from an
unsaturated repository would be less than or greater than the Table 1 (40 CFR 191)
release limits. ...
c) "The issues document does not accurately characterize the potential for gaseous
carbon-14 releases from the repository to the environment, although the Subcommittee
notes it may not be possible to do so based on currently available information. The EPA
document's assumptions about release mechanisms and rates of release from the wastes
and containers, and the transport mechanisms and rates, do not appear to be supported by
sound technical justifications.
d) "The description of the effectiveness of engineered barriers designed to reduce or
impede releases is not adequate because there has been little research and development of
engineered barriers specifically designed to contain carbon-14 in unsaturated repository.
... (The significance of the reduction in the release would depend on the containment
time relative to the 5,730 year half-life of carbon-14.) Therefore, the Subcommittee
encourages investigation of the use of multiple barriers to retard migration of carbon-14 to
the accessible environment.
e) "EPA needs to revise the description in the document of the physical and chemical
retardation and transport of carbon-14 from the waste repository to the surface, because
the hypothesis that the principal transport mechanism in flat terrain would be diffusion is
incorrect. ..."
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f) "In responding to the broader issue of risk reduction, the Subcommittee notes that
optimizing site selection on the basis of a single criterion may cause a change in optimal
conditions for other criteria. For example, carbon-14 releases to an accessible
environment would probably be less from a saturated site than from an unsaturated site,
but risks from other radionuclides may be greater or smaller depending on a number of
factors."
6.6 Low-Level Radioactive Waste Disposal
One of the first tasks assigned to the newly established RAC was the review of the ORP's
"BID on Low-Level Radioactive Waste Disposal," initiated in February of 1985 (Appendix A,
Report #5). The parts of the report dealing with the Agency's risk assessment methodology were
discussed in Section 3.1 of this retrospective report. The present section deals primarily with the
other issues covered in the RAC report and is based largely on the cover letter accompanying the
submission of the report to the EPA.
The Committee was asked by the ORP to address 11 issues associated with the draft
document: 1) sorption characteristics and environmental behavior of carbon-14; 2) behavior of
carbon-14 and tritium in the disposal trench; 3) the reasonableness of time spans for risk
assessment; 4) identification of disposal pathways from disposal of low-level wastes; 5) exposure
pathways from unregulated disposal of "below regulatory concern" wastes; 6) generic
characterization of disposal sites; 7) appropriateness of site-independent modeling parameters; 8)
appropriateness of model scale and approach; 9) parameters investigated in sensitivity analysis;
10) uncertainty in risk assessments; and 11) adequacy of the range of low-level waste disposal
methods.
The Committee's major findings were:
1) The Agency should explain how it would use the information in the document to arrive
at and support a generally applicable radiation protection standard for the disposal of low-
level radioactive wastes.
2) Risk assessments involve the use of a variety of complex models which are predicated
on the legitimacy of certain assumptions and the appropriateness of the data that are
utilized. It is important that the uncertainties in these data and calculational procedures be
fully described at the outset.
3) The Committee believed that the time spans over which the analyses were made, 1,000
and 10,000 years, were unrealistically long and found the assumptions that social changes,
advances in public health, and population growth will not occur over a 10,000 year period
to be unpersuasive. ORP should select a time frame based on explicit engineering
considerations, biological reasonableness, or preferably both.
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4) [The recommendations regarding risk assessment have been dealt with in Section 3.1
of this retrospective report. The only additional point that should be made is that risk
should be expressed in terms of risk to an individual and not in terms of numbers of death
or genetic effects within populations of dissimilar size and demographic characteristics.]
5) The Committee identified some technical weaknesses that could be remedied by better
use of existing information, and it presented some areas in need of additional research.
These included: (a) Improved understanding of the geohydrology of long-lived, mobile
radionuclides with particular attention given to tritium, carbon-14, technetium-99, iodine-
129, and neptunium-23 7. The studies should include an evaluation of the transport of
various chemical forms in a variety of soil types, (b) Better understanding of the behavior
of long-lived mobile radionuclides in the disposal trench. Specific leach rates for these
radionuclides in their various physical and chemical forms should be determined; these
differences would affect the rate of movement of radiocarbon from the site and the time at
which the maximum exposure rate occurs after closure, (c) The Committee further
recommended that the Agency support research in the technical areas where major
uncertainties exist. In addition, future studies on the biological effects of radiation should
include particularly the assessment of human studies on low-dose risk estimation and the
evaluation of dose response information and relative biological effectiveness (RBE) from
human and other biological systems.
Overall, the Committee believed that, with incorporation of the recommended changes,
the document would prove useful to the Agency and to the general public in promoting a wider
understanding of the options for the disposal of low-level radioactive wastes.
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7. RADON RELATED ISSUES
Over the period covered by the present review, issues related to radon have by far been
most prominent, having been dealt with in 16 of the total 36 RAC reports. For convenience, this
part of the retrospective report has been divided into several sub-categories.
7.1 Radon Epidemiology Proposal
In February, 1986, EPA's Office of Health Research in the Office of Research and
Development (ORD) asked the RAC to review a proposal, from the Maine Medical Center and
the University of Maine, for an epidemiological study of indoor radon entitled "Health Effects of
Waterborne Radon," to be conducted in the State of Maine. A Radioepidemiological
Subcommittee was formed to carry out the review. The ORD posed two main questions to the
reviewers:
1) Can further epidemiological study contribute to an understanding of the risks of lung
cancer associated with household exposures?
2) Is the proposed study under review by the ORD appropriately designed to address this
risk?
The Subcommittee noted (Appendix A, Report #7) that the relationship between radon
exposure and lung cancer in the domestic population was based on extrapolation from data on
uranium miners and that epidemiological studies on people exposed in the home were only then
being proposed or conducted. Since the proposed Maine study would be assessing a "middle
range" of radon exposures, the Subcommittee concluded that data from a successful study
combined with those from other studies to be conducted elsewhere could clarify the present
understanding of risk vs. radon exposure.
The second conclusion, that the proposed study would not likely provide useful
information on the issue of waterborne radon risks, was based on a number of perceived problems
of the study, among which were the relatively low number of cases available and the difficulty of
estimating indoor radon exposures, including those of deceased individuals. In addition, the
Subcommittee noted that even in Maine, where the water in many wells contains high levels of
radon, the radon in water is usually a minor contributor to radon in indoor air. Overall, while
supporting the need for radioepidemiological studies on radon in indoor air, the Subcommittee
recommended that the Agency not undertake the proposed study as then currently planned.
By way of follow-up information, the applicants resubmitted the study proposal to the
EPA the following year and at that time the Agency assigned it to an outside group, not affiliated
with the RAC, for a site visit and review. This latter group recommended funding of the study,
with reduced budget, contingent on the resolution of a number of issues raised in the second
review. The eventual outcome was that the proposed study was not funded.
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7.2. Radon Measurement and Mitigation
In January 1986, at the time that the issue of environmental radon was beginning to be
appreciated by the general public, the RAC was asked by EPA's Office of Environmental
Engineering and Technology Demonstration (OEETD) to review the Agency's Radon Mitigation
Research Plan. Two reports were prepared by the Radon Mitigation Subcommittee, which was
established for this purpose (Appendix A, Reports #8 and #12). Overall, the Subcommittee found
OEETD's general approach to be reasonable but made the recommendations that the number of
cells in the mitigation test matrix be reduced by combining techniques which have similar effects,
that increased attention be given to pre- and post-mitigation measurements, and that geological
parameters relating to the source terms not be included in the mitigation matrix when not
susceptible to mitigation. The Subcommittee also suggested a series of criteria for prioritizing the
development of various mitigation techniques. Additionally, it commented on the need for being
able to relate short-term to longer term measurements and how these may be compared to EPA's
annual guidance level of 4 pCi/liter of radon in indoor air, an issue that would come up again (cf
Appendix A, Report #22 later in this Section). It was also recommended that greater emphasis be
placed on new construction mitigation to prevent radon problems from developing in new
construction on high-risk lands. Finally, reviews of existing literature and of the details of
statistical testing were considered to be essential for judging the scientific merit of a mitigation
approach.
In its subsequent report (Appendix A, Report #12) the Subcommittee expanded on several
of the above points, such as the variables to be addressed by the test matrix, the collection and
management of useful data, and data analysis. The issue of cost effectiveness was given a broad
discussion and the committee endorsed the goal of OEETD to develop cost-effective, in
preference to low-cost, mitigation techniques. The Subcommittee recommended that different
definitions of cost-effectiveness be developed from the perspectives of the different interested
groups: mitigators, homeowners, and policy makers.
Radon risk assessments and mitigation decisions both depend crucially on the ability to
test for radon with reasonable accuracy. The RAC, in the fall of 1987, was asked to review
ORP's "Radon Measurement Proficiency Program " which had been established in response to
requests from private laboratories and State agencies to assist these initially in choice of methods
and equipment, and to assure their measurement capabilities in the public interest. The RAC
formed the Radon Measurement Subcommittee to conduct the review. The Subcommittee
addressed performance standards, statistical methods, standard measurement protocols,
participant's procedures, blind tests of passive devices, consensus standards and voluntary
accreditation, and user fees. The Subcommittee's recommendations (Appendix A, Report #18)
included the following points:
a) development of separate objectives for devices or methods used for screening,
diagnostic measurements, and exposure evaluations;
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b) consideration of different testing protocols for passive devices and active
measurements;
c) design of the testing program to obtain independent measurements from each
device or method tested;
d) the need to conduct blind testing, wherever practicable, as in the instance of
passive measurement devices; and
e) the assignment of a full-time statistician to the measurement protocol program, at
least until it was well established.
The Subcommittee recommended that serious consideration be given to establishing
consensus standards and voluntary accreditation procedures. Finally, since a successful program
would require adequate and continuous support, it recommended that EPA explore all possible
avenues, including user fees.
The RAC had long recommended that radon measurements that were intended to be
compared with the action level proposed by EPA for indoor air (i.e., an annual average of 4
pCi/liter) should preferably be conducted over a 12-month period. Practical considerations
argued against such a long testing period which would not be acceptable to homeowners wanting
to test for radon in their homes. In 1990 the RAC was asked to review the ORP's approach to
analyzing the effects of substituting short-term tests for long-term tests in determining the
concentration of radon gas in homes.
The Committee (Appendix A, Report #22) endorsed the use of along-term test conducted
in the lowest lived-in space as the standard against which other test results should be judged;
noted that the lower the radon level, the less accurately informed the homeowner is likely to be by
results obtained with currently available test devices; expressed concern about the false positive
and negative rates that are likely to result from short-term tests near an assumed action level of 4
pCi/L; and noted that the long-term test, when properly done, provides a more scientifically
appropriate basis for mitigation decisions, particularly in the range of radon levels most commonly
found in U.S. homes. The Committee observed that improving the methods and/or improving the
means of estimating actual radon exposure could lead to a greater number of correct mitigation
decisions.
During the second half of 1993, the RAC reviewed the study design for the Office of
Radiation and Indoor Air's (ORIA's) "Radon Measurement Protocol Evaluation Study" (Appendix
A, Report #43). An initial discussion of this proposed study was held with ORIA staff at the RAC
meeting in November, 1992, at which a number of suggestions were made by the Committee,
many of which were addressed in the final draft protocol. A number of the issues dealt with in the
Agency's document may be viewed as having their origins in earlier EPA documents and RAC
reviews, most notably in connection with the revised "Citizen's Guide to Radon" and the
"Homebuyer's and Seller's Guide to Radon" (see Sections 7.6 and 7.7 of this review).
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In the charge to the Committee, ORIA asked three questions, each of which is listed
below, together with an abbreviated version of the Committee's response. In addition, the
Committee's further discussion and recommendations for the study are summarized.
(1) Does the study accumulate data pertinent to further investigating the use of short-
term measurements for making mitigation decisions?
"Overall, the study design will gather data that will permit pertinent comparisons
of results from the different measurement methods with the long-term (annual) average.
Because the study population is those houses that participated in the "National
Residential Radon Survey" (see Section 7.4 of this report), the collection of additional
long-term data will permit the Agency to examine the degree of temporal variability in the
long-term average radon concentration. Since there are very few data enabling such
comparisons, the Committee believes this will be a very useful result of the study."
(2) Are the Data Quality Objectives (DQOs) reasonable?
[The DQOs for the study were: (a) Detect false positive and false negative errors
with probability of at least 0.80, if the error rates are 0.03 or higher; (b) Have a 95%
upper confidence bound no higher than 0.05 for each study cell, if no false positive or false
negative errors are observed for that particular cell; (c) Have power of at least 0.80 for
detecting a difference between a false positive or false negative error rate of 0.05 and an
error rate of 0.15.]
"The Committee believes that the DQOs are reasonable for comparison to the
Agency's guideline of 4 pCi/L."
(3) Does the study design seem reasonable to achieve the Data Quality Objectives
(DQOs)?
"The limiting case in each of the DQOs is the design cell for which the Agency
expects 70 responses, and as the study protocol document states, this sample cell will not
meet the third DQO, although the design does maximize the power for this one cell. The
Committee does not believe that the failure to meet this DQO for only one of the cells is
an important limitation to the study design. The ability for this design cell to meet the first
two DQOs depends critically on whether the projected 70 percent response rate is
achieved. ... However, at a sample size of 70, both these DQOs are just met. Thus the
Committee is concerned that, should the response rate fall below that projected, meeting
one or both of these DQOs will be more difficult. In all other design cells, the sample size
is sufficient to meet the DQOs."
Among its additional concerns, the Committee believed that the study document was
incomplete in that it did not discuss the statistical analyses proposed for the data resulting from
the study; in particular the comparisons to be made among the different testing devices, methods,
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locations and seasons. No mention had been made as to how the data analysis pertinent to each
question would be conducted. The Committee recommended that, as the Agency completed its
planning for the evaluation study, ORIA discuss with the Committee the hypotheses and/or
specific questions to be addressed by the study. It was also not clear to the Committee how the
final results were to be presented; in particular, it appeared to the Committee that the metric for
comparison among the results was "mitigation decision-making" rather than a direct comparison
of measured radon concentrations. In order to evaluate the results of this study across all seasons,
testing devices, method and device locations, the RAC recommended that the results of each
measurement be presented in units of concentration or as ratios of concentrations with their
attendant uncertainties (both precision and accuracy), and that the raw data be preserved in such a
format.
A further recommendation of the Committee was that the Agency not examine the effect
of climate based on the present study design since it did not appear that the climate zone effects
could be determined by the use of surrogate analyses of the data obtained by house structure type,
even though there appeared to be some geographical overlap between the two parameters. With
regard to the comparison of short-term testing results with annual average concentrations, the
Committee believed that the Agency should consider apportioning the study houses on the basis
of whether the first-floor concentration was above or below 4 pCi/L, rather than using the "lowest
level" as this division criterion. In addition to the issue of potential differences in radon
concentration dynamics, using the first floor concentration as a division point provides a uniform
basis for this decision across all houses in the study. All houses have a "firstfloor, " which is often
the level most frequently occupied by the inhabitants.
Finally, the Committee suggested that the resources for the part of the study that included
the 2-day measurements might be better allocated to another short-term testing method for which
the comparison data set would currently be less extensive, and it further encouraged the Agency
consider to whether there should be a small sub-study conducted with continuous radon monitors
in view of the fact that the "Homebuyer's and Seller's Guide to Radon" acknowledged their use
as a short-term measurement technique.
7.3 Radon Science Initiative
In the early part of 1993 the RAC established a Radon Science Subcommittee to carry out
the self-initiated task of providing EPA with information and advice regarding the expanding field
of radon research. Most of the Subcommittee's ten members were individuals actively engaged in
research on radon and who were recruited from outside the RAC and came to the Subcommittee
with distinct and varied views about radon research. The Subcommittee met in February, 1993 to
initiate discussion of radon research activities and the needs of importance to EPA in this area. At
that time, the Subcommittee identified three broad areas of concern in the radon field for which
they believed additional research was required:
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1) Radon exposure and risk assessment
2) Radon risk control/reduction/mitigation strategies
3) Radon risk communication.
The Subcommittee strongly believed that all three of these areas need to be addressed by
EPA or by other agencies. This was considered to be particularly true in view of the
recommendations set forth in the SAB's document: "Reducing Risk: Setting Priorities and
Strategies for Environmental Protection" (Appendix B, EPA-SAB-EC-90-021), which argues
that resources should be allocated on the basis of opportunities for the greatest risk reduction and
concludes that radon is among the environmental problems posing the greatest potential health
risk. In a self-initiated letter to the Administrator (Appendix A, Report #38), the Subcommittee
expressed concern that funding within EPA for additional research on mitigation of radon risk
appeared to have been reduced to zero. This action was deemed to create a void in further radon
mitigation research that would not be easily filled by current or planned research activities in this
or in other agencies. The decision to discontinue funding by the Agency for radon control
research would, in addition to terminating efforts with substantial potential for risk reduction,
effectively disperse the expertise developed within the Agency.
The full report of the Radon Science Initiative Subcommittee was substantially completed
in the Fall of 1994 and will be forwarded to the Administrator early in calendar year 1995
(Appendix A, Report #45). The Subcommittee's goal was to develop a comprehensive view, both
of radon research undertaken within or for the EPA and, to the extent possible, of research efforts
underway or sponsored by other agencies. This appraisal sought to determine what further
research would be needed to improve the scientific basis of our understanding of the occurrence,
behavior, health effects and exposure reduction methods for radon and its radioactive decay
products. Overall, the Subcommittee considered research that would lead to reduced radon risks
and/or reduced uncertainty about radon risks to be important to EPA's mission of protecting
public health and the environment.
In the area of risk reduction, the Subcommittee agreed with the principle articulated in
SAB's "Reducing Risk" report (EPA-SAB-EC-90-021). Recommended areas of radon research
that addressed risk reduction generally related to radon-resistant construction of new homes,
identification of homes with elevated radon levels, mitigation of homes, and public participation.
As to uncertainty reduction, the Subcommittee, like RAC and the SAB in general, believed that
quantitative uncertainly analysis (and disclosure of that analysis) was increasingly important to
scientists and that it would become the norm for those making decisions based, at least in part, on
science. Recommended radon research aiming at uncertainty reduction generally related to radon
measurement, exposure and dose assessment, dose rate effects, risk assessment, and factors such
as smoking or genetic susceptibility that would affect the individual's likelihood of developing
cancer.
A broad range of research topics was identified, based on the assembled expertise of the
Subcommittee members, and through discussions with colleagues and staff members of the EPA
and other Federal agencies. Through further Subcommittee discussion, a consensus list of specific
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research recommendations was developed; the list of broad research areas is shown below. The
Radon Science Initiative report should be consulted for a more detailed list and description of
individual research items.
1) Factors Affecting the Bases for Radon Risk Estimates:
Epidemiology
Mechanistic studies
Dosimetric studies
General issues In radiation biology pertinent to radon
2) Factors Affecting Concentrations, Exposures, and Exposure Assessment:
Regions with high radon susceptibility
Measurement and interpretation methods
Factors affecting total exposure and dose
3) Risks from Ingestion of Radon in Drinking Water:
Gastrointestinal and non-gastrointestinal cancer
4) Exposure/Dose/Risk Reduction Methods:
Source control for retrofit and new applications
Radon and/or progeny reduction methods
Reduction in water-borne radon concentrations
5) Risk Communication:
Communicating technical information and scientific uncertainly
Motivating public action: goals for risk communication
Public participation
The Subcommittee further endeavored to prioritize the research and to select high- and
medium-priority topics. In discussing priorities, an approximate 3 year time horizon was used as
the distinction between short- and long-term research, recognizing that in some cases, certain
research areas would not fall easily into either category. The recommendations that follow
represent the Committee's combined expert judgment as to the areas in which a significant
reduction in either the uncertainty of current risk estimates, or in domestic radon risk itself, can
potentially be obtained.
High Priority - Short term:
1) Durability and performance of active and passive mitigation systems
High Priority - Long Term:
1) Smoking and radon synergism and effects in non- smokers
2) Risks at low cumulative doses and low dose rates
Medium Priority - Short Term:
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1) Development of methods to determine high radon areas
2) Improvements in the accuracy and precision of radon measurement methods
and protocols
3) Better characterization of mine exposure comparison to home exposure
stressing differences as well as similarities
Medium Priority - Long Term:
1) Development of potential physical and biological markers of exposure or dose
An overarching area of research is the combined topic of continued research the
communication of technical information along with the uncertainties associated with the
information. Because it covers a number of issue areas, not just radon, it was not included in the
list of research priorities. This area is an extremely important part of the link between policies to
reduce radiation exposures and obtaining public action. Studies to improve the communication of
information about radon should contribute to the overall goal of reducing radon risk while
generally improving knowledge and awareness of the issue. The Subcommittee felt that the goals
of improving the technical content of public information and improving the communication
process with the public are not incompatible and that research in these areas is vital to providing
the basis for decision-making by members of the public.
7.4 National Residential Radon Survey
In June, 1986, the ORP asked the SAB's RAC to review the design for a national radon
survey. A National Radon Survey Subcommittee was established to carry out this review. At the
Subcommittee's first meeting, in September, it became apparent that the design being presented
was to be viewed as a "preliminary" document and that the Agency planned substantial revisions.
The Subcommittee therefore did not prepare a report at that time. It did, however, offer a
number of suggestions to the Agency, the most important being that if the Agency wanted a clear
understanding of indoor radon distribution it would have to do a rigorous probability-based
survey independent of the state surveys that the Agency had hoped might be used to supplement
the national survey. The revised survey design document was transmitted to SAB the following
spring and the Subcommittee reconvened on June 12, 1987. According to the ORP, the primary
objective of the national radon survey was to determine the frequency distributions of the radon
concentrations in residential structures. This would provide data on the average indoor residential
radon levels to which the population of the United States is exposed. It would also provide
information on the number of homes that exceed various radon levels.
The Subcommittee found (Appendix A, Report #11) that the document presented a valid
approach to designing a national radon survey. It did express strong concern, however, about the
bias that might arise if only owner-occupied housing were to be sampled since at most 60% of
dwelling units in the U.S. fall into this category, and it urged the Agency to include rental units as
well in the study. A summary of the Subcommittee's other major conclusions and
recommendations follows:
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a) The primary objective of the survey, that of determining the nationwide frequency
distribution of radon concentrations in residential structures, is important and achievable
with adequate precision within the study design. Achievement of secondary objectives,
such as regional distribution estimates, is also possible.
b) A pretest should be conducted to determine the relative advantages of a telephone
survey versus face-to-face interview.
c) Occupancy figures for individuals should also be obtained since this will allow
estimates of effective dose equivalent that provides a better representation of the radon
exposure than concentration and can be readily translated in terms of potential health
effect to the public.
The national radon survey could also be a valuable mechanism for investigating
correlations between radon and certain variables which would constitute a major contribution of
the national radon survey. To realize this possibility, additional data should be collected including
bedrock geology, climate, basement radon levels, housing characteristics, and household
heating/air conditioning practices.
Only residential structures were included in the objectives covered in the ORP's original
memorandum to the SAB. It was noted by the Subcommittee that the Superfund Amendment and
Reauthorization Act (SARA) stated that EPA was to include "structures where people normally
live and work, including educational institutions" in the national assessment of radon gas.
The Subcommittee identified some additional areas of concern and also recommended that
the Agency consider how the results of the survey would be used and how the information
derived would be reported. Both the RAC and the Subcommittee concluded that the study was
important from a national health point of view and that all efforts must be made to insure that a
survey of high quality was conducted; an inadequate national radon survey would be a disservice
because it might well prevent the execution of any future study of significant scientific value.
7.5 National School Radon Survey
In June, 1990, the National Radon Survey Review Subcommittee reviewed the ORP's
design options for the National School Radon Survey. These design options attempted to
respond to the requirements and constraints set by Congress in the Indoor Radon Abatement Act
and Section 118 (K) of the Superfund Amendments and Reauthorization Act. Since the survey
was scheduled to take place during the 1990-91 school year heating season, the ORP utilized the
preliminary findings of the Subcommittee to revise part of its study plan. The data collection was
completed on schedule and the report (Appendix A, Report #27) was submitted after-the-fact.
The survey document presented two alternative options to be considered. The
Subcommittee found that the document presented statistically valid sampling designs for selecting
school districts for the survey. Design Option II was considered preferable because, while it was
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not much more complex or costly than Design Option I, it provided for 25 probability sampling
units within which alpha track detector measurements for both residences and schools would be
available for comparison. However, the Subcommittee raised concerns about the primary radon
measurement method chosen for a study of this importance. The original proposal to use short-
term charcoal canister measurements was expected to produce results of tenuous reliability
because they could be defended only as screening data and not as valid measurements from which
realistic exposures might be derived. In response to these concerns, ORP decided to extend the
charcoal canister deployment period from 2 to 7 days. The SAB was pleased by this revision but
still wished to stress that conclusions from screening data and the preparation of technical
documents using such data to support national programs could compromise the positive aspects
of the school survey. It should be emphasized, however, that short of a continuous measurement
with alpha detectors or repeated short-term measurements during the school year, the Agency's
decision to use measurements made over a longer period that included the school week instead of
the originally planned weekend measurements constituted a greater improvement in the survey
design than could be achieved with any other single design change. The Subcommittee also noted
that consideration of how the results were to be used, prior to initiating the survey, would greatly
enhance the data collection protocol and thereby strengthen the quality and defensibility of the
study.
7.6 Citizen's Guide to Radon
In June, 1988, the Agency published its initial "Citizen's Guide to Radon" as a means to
inform the public about risks associated with exposure to radon in indoor air and to provide
guidance in regard to when mitigation efforts should be considered. Although the RAC received
a briefing on the guide, it was not asked to review the document as a committee but was invited
to submit comments as individuals. In 1991 ORP drafted a revised "Guide to Radon, " and at this
time the SAB was requested to provide a review of the draft document. Supplemental material
relating to the "Guide " was provided at the RAC meeting in September, 1991. In the charge from
the ORP, RAC was asked to address specifically 1) whether the document properly reflected
current scientific knowledge on radon, particularly in the area of short- and long-term testing of
radon, and 2) whether the Agency had appropriately incorporated the available technical
information in reaching the policy recommendation embodied in the test protocol.
The Committee in its review (Appendix A, Report # 29) accepted the premise that
measurements on the lowest living level are the most relevant since they best reflect residential
radon exposures to humans. The Committee continued to affirm that a long-term test was the
best basis for a mitigation decision; however, if a short-term measurement were to exceed the 4
pCi/L action level several fold, the RAC recommended that a short-term confirmatory test be
made immediately. The "Guide" should make it clear that a single short-term test is not decisive
and at least two short-term tests are needed before a decision to fix a home is made.
In regard to comparing the risk of fatalities from different causes, the Committee
recommended that a clear distinction be made (in Fig. 1 of the "Guide"} between the calculated
fatalities from radon based on mathematical models and the actuarial deaths from other causes.
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The Committee also expressed concern about the Agency's other risk comparison charts; e.g., to
compare radon risk to risk from chest X-rays (a risk that most people do not understand) might
increase the fear of a medically beneficial diagnostic procedure. The risk from a hazardous waste
site would be equally poorly understood by the public. If risks such as heart attacks are
dependent on smoking status, the appropriate risk should be used when comparing with radon
risk. To some Committee members automobile accident deaths was a more acceptable risk
comparison. The Committee also urged that the greater risk from radon exposure to smokers be
further emphasized in some specific places of the report.
7.7 Homebuyer's and Seller's Guide to Radon
In January, 1992, the RAC was asked to review the scientific basis of the real estate
testing protocol options proposed in ORP's draft revised "Homebuyer's and Seller's Guide to
Radon. " A briefing by the Agency was given at the February, 1992 RAC meeting. This
document was anticipated in the revised Citizen's Guide and was to be considered a companion to
that earlier document.
The Committee had long held the view that all radon remediation decisions should be
based on estimates of exposures to individuals. The Committee had for some time advocated a
year-long integrated radon concentration measurement, taken in the lowest lived-in space,
because this measurement most accurately reflected the average annual radon concentration in a
home (exposure depending also on the time spent in a particular area). The Committee realized,
however, that the scientifically best option was not the currently most realistic one for real estate
transactions where decisions may be made in matters of days or weeks. In proposing real estate
testing protocols, the Committee noted that EPA must also consider a number of practical
concerns that are not strictly part of science; for example: tampering or interference with the test
will make it invalid; a testing protocol that is too complicated or costly will discourage testing; in
addition, in warm weather home sellers without air conditioning are unlikely to comply with the
requirement to close up their houses for several days during testing.
Overall, the Committee recommended (Appendix A, Report #33) that the real estate
testing protocols should be consistent with the "Citizen's Guide to Radon" but that the protocols
should not be constrained by those adopted for the Citizen's Guide. Where the two protocols
differ the Agency should provide an explanation for this difference. In reviewing the five
protocols presented by EPA, the Committee considered the many variables affecting radon
concentration: location within the home; use patterns of heating, ventilation and air conditioning;
and variations over time (time of day, season and weather). The Committee found that the data
and analyses made available to it were insufficient to make decisions about the protocols, and its
recommendations therefore included the professional judgment of the Committee. Some
controversy existed about the location for testing, the commercial radon testing community
having routinely tested on the basement level where test results generally were less variable but
more likely to give higher radon concentration values than in the lowest lived-in area. In its
report the Committee recommended that short-term testing be conducted "at the lowest level of
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the home that is finished in a manner suitable for occupancy, whether or not the seller lives in
that area."
Two simultaneous tests run side-by-side would improve the precision of the measurement
applicable to the time period of the measurement; two sequential tests would improve the
accuracy of estimating an annual average concentration by increasing the time period over which
measurement is made. The material presented to the Committee did not provide a conclusive
basis for choosing between simultaneous and consecutive testing.
With short-term testing, both false positive and false negative results will occur at a higher
frequency than with long-term testing properly performed. If short-term testing is chosen, the
Committee recommended that:
a) Short-term testing should be conducted on the lowest level of the home that is
finished in a manner suitable for occupancy, whether or not the seller lives in that area.
b) Two measurements should be conducted if passive short-term integrating monitors
are used; each measurement should span at least two days or preferably longer.
c) A non-passive continuous radon monitor could also be used, with data collection
over a time period sufficient to minimize the effects of daily and day-to-day variations in
radon concentration. Again the time period should be at least two days and preferably
longer.
d) Methods should be employed to reduce or eliminate inadvertent or deliberate
interference with the measurement devices or violation of the closed-house condition to
ensure the integrity of the results.
e) The "Homebuyer's and Seller's Guide to Radon" should carefully portray 4 pCi/L
as the recommended EPA action level for an annual concentration and stress that a 4
pCi/L short-term test result does not necessarily translate to an annual average
concentration of this magnitude.
f) The Committee recommended that the "Guide" address alternate approaches such
as escrow account or "radon insurance" type arrangements under which long-term testing
and any resulting mitigation would be conducted after the sale of the home and at no
further monetary expense to the homebuyer, and
g) Finally, the Committee believed that the Agency should conduct studies directed
toward improving the analyses of both the precision and accuracy of the various
measurement methods, testing protocols, and interpretive procedures.
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8. NON-IONIZING RADIATION
8.1 Earlier Concerns about the Non-Ionizing Radiation Program
The issue of non-ionizing radiation has concerned the SAB for a number of years and the
initial report in this area (Appendix A, Report #2) in fact preceded the establishment of the RAC,
having been prepared by a subcommittee appointed by the Executive Committee of SAB to
review EPA's document "Biological Effects of Radiofrequency Radiation. " This document was
prepared for the ORP as a BID for the Agency's development of radiation protection guidance,
for use by Federal agencies to limit exposure of the general public to radiofrequency radiation.
The Subcommittee found the document, as amended in response to its earlier comments,
to be "an adequate review of the scientific literature" that could serve as a basis for the
development of the intended radiation protection guidance. In its further comments the
Subcommittee stated that EPA ought to use its own professional staff to keep abreast of
developments in this field and that it "should continue to strengthen its program of extramural
research and also its in-house research on the health effects of radiofrequency radiation." In
addition, the Subcommittee identified certain research areas that it believed needed the Agency's
attention.
At the first meeting of the newly established RAC, on February 4, 1985, the Committee
learned that the ORP's resources had been repeatedly reduced. At its second meeting, the
Committee learned that EPA's Health Effect Laboratory's non-ionizing radiation research program
would be eliminated in FY 1986. The Committee subsequently addressed a letter to EPA
Administrator Lee M. Thomas expressing its reaction to the latter information (Appendix A,
Report #4). The following paragraphs are quoted from that letter:
a) "We would like to convey to you our strong concern that this unique research
capability will be lost if this action is carried out. The decision to cease research in this
area goes counter to the advice given by the SAB earlier and counter to the Agency's need
to maintain an analytical and research capability if it is to make informed regulatory
decisions. In addition, advances in the field of non-ionizing research are changing our
understanding of the biological mechanisms at work.
b) "EPA should continue and strengthen its program of extramural research and also its
in-house research on the health effects of radiofrequency radiation. This is necessary not
only to keep abreast of the field but also because the research itself is invaluable to the
nation, as attested by the fact that a considerable part of the scientific results reported in
its recent (1984) review of the field derives from work done at EPA's own laboratories."
In addition the Committee reiterated the list of non-ionizing radiation research areas needing
attention, as originally presented in its earlier report (Appendix A, Report #2).
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Within a relatively short time thereafter, the RAC was appraised of the ORP's proposal
"to 'defer' all Agency involvement in non-ionizing radiation after the Guidance to limit exposure
(now being developed) is issued." The phasing out of this area of activity was considered despite
renewed national interest in the effects of non-ionizing radiation as a possible cancer promoter.
Presumably this decision was made on the basis of budget constraints and the need to focus on
larger tasks with perceived higher priorities. With the encouragement of SAB's Executive
Committee, the RAC submitted a letter (Appendix A, Report #14) to the EPA Administrator
drawing attention to the need for EPA to maintain a viable Federal presence in the area of non-
ionizing radiation and to provide technical assistance to other agencies in their implementation and
compliance with its Guidance. A copy of the Committee's previous report (Appendix A, Report
#2) was appended.
In May, 1990, RAC again expressed its concern in regard to EPA's lack of attention to
non-ionizing radiation and it submitted a letter (Appendix A, Report #20) to the Administrator,
pointing out that the earlier Guidance development and the Agency's own research in this area had
been terminated despite objections from other Federal agencies, the academic community, and the
Agency's own Science Advisory Board. The following two paragraphs are quoted from the letter:
a) "It is the Board's present view that its earlier recommendations have lost none of their
force. In addition, new circumstances have arisen that further support these
recommendations. Recent research has focused attention on nonionizing electric and
magnetic fields well below the usual range, down to 60-Hz power line and lower
frequencies, as well as fields modulated at these extremely low frequencies (ELF).
Reports in recent issues of scientific journals have suggested the possibility that ELF and
power frequency fields may produce detrimental health effects. Some of these studies
suggest that cancer is associated with exposure to alternating current magnetic fields. The
Agency's Human Health Assessment Group is expected to draw attention to this
possibility in its forthcoming report.
b) "All these circumstances reinforce our view that the Agency should resume its efforts
in this area. It is entirely appropriate for EPA actively to conduct research on nonionizing
radiation, including ELF effects. Even though the Department of Energy and the National
Cancer Institute conduct research on ELF effects, EPA will be called upon to address the
public health and environmental issues involved. The fact that other agencies, state and
local authorities, and foreign governments have looked to EPA for assistance on this issue
reinforces the need for EPA to actively undertake this ELF research."
8.2 Potential Carcinogenicity of Electromagnetic Fields
In October, 1990, the SAB was asked to review the draft report "Evaluation of the
Potential Carcinogenicity of Electromagnetic Fields" which had been prepared for the Agency by
an outside contractor. By this time the question of whether or not electric power transmission
lines could cause cancer had been elevated to an issue of great public concern. The RAC
appointed a "Nonionizing Electric and Magnetic Fields Subcommittee " with extensive
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participation of outside experts to carry out the review (Appendix A, Report #31). The
Subcommittee found serious deficiencies with the EPA document, including internal
inconsistencies, that could not be remedied by editing alone, and recommended "logical
reorganization" and complete rewriting. Based on the available information, however, the
Subcommittee nevertheless expressed its viewpoints on several scientific issues and responded to
a number of questions posed to it in the Agency's charge. In the area of epidemiology it found the
evidence "suggestive of an association between surrogate measurements of magnetic field
exposure and certain cancer outcomes" (such as childhood leukemia), but refrained from drawing
the inference of cancer causality from these associations at this time. The Subcommittee also
pointed out that low-frequency electric and magnetic fields do not carry enough energy to break
chemical bonds and produce mutations directly, but allowed that the incidence of cancer might
well be affected by an agent that does not produce mutations.
In response to the Agency's charge, the Committee stated that currently available
information is insufficient to conclude that electric and magnetic fields are carcinogenic although
some of the data suggested the existence of mechanisms by which other human health effects
might be inferred. It also concluded that the Agency's carcinogen classification system is not
applicable to electric and magnetic fields because of present major uncertainties. Further, there
was insufficient information to designate specific values of magnetic field strength as hazardous to
human health.
Two specific policy recommendations were volunteered by the Subcommittee:
a) "... the question of electric and magnetic field effects on biological systems is
important and exceptionally challenging, and ... the report should be rewritten by EPA,
and then reviewed by the Science Advisory Board."
b) "EPA should complete its efforts in regard to RF electromagnetic fields (including
microwaves) and issue exposure guidelines independent of present issues pertaining to
lower frequencies."
8.3 Research Strategy for Electric and Magnetic Fields
As a follow-up activity to the above review, the Subcommittee was asked to review EPA's
document "A Research Strategy for Electric and Magnetic Fields: Research Needs and
Priorities." The Subcommittee's response was submitted in a letter report (Appendix A, Report
#32). It concluded that all of the topics identified in the Agency's document were relevant to
EPA's mission but that a number of important topics were missing if the "Research Strategy"
were to represent a national research agenda, a point that was not clear from the document itself.
Although well-written and informative, the document provided insufficient details for setting
specific research goals and priorities and for ensuring implementation of the strategy.
Whereas priorities for broad research categories were identified, the EPA document did
not establish specific research priorities or provide estimates of resources or time needed to
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undertake the research. Finally, the Subcommittee recommended that research needs and
priorities ought to be identified within a broad interagency scope which would then provide the
basis for effective interagency cooperation and communication.
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9. MISCELLANEOUS GENERIC REPORTS
Over the years, the RAC has generated a number of self-initiated reports on issues that
were not limited to a single document or subject under review. Three of these are reviewed
below, in chronological order.
9.1 Status of EPA Radionuclide Models
The following text represents excerpts of a letter submitted to the EPA Administrator in
January, 1992 (Appendix A, Report #23). The comments in the letter specifically addressed the
documents produced in support of potential rulemaking for NESHAP (Appendix A, Reports #17
and #19) and for radionuclides in drinking water (Appendix A, Report #26).
"Many Science Advisory Board reports submitted to the Agency have included
constructive criticisms of the models, databases, and uncertainty analyses used by EPA.
These criticisms have not been unique to the radiation-related activities of the Office of
Radiation Programs, but they are pertinent to those activities. Therefore, the Radiation
Advisory Committee of the SAB would like to share with you its view of the limited
progress it has seen in this area and problems that remain. The Committee does so
because outmoded or inappropriate models, supported by inadequate data and executed to
produce conservative results, can lead to significant overestimates of impact for specific
potential hazards.
"In addition, selection of regulatory limits based on overestimates may lead to remedial
actions unwarranted by actual risks and thus deprive other activities of the resources
needed for protection of public health and the environment. The Committee strongly
recommends that the EPA at this time assign a high priority to the development of
comprehensive models and data sets for the transport of radionuclides in the environment.
"This commentary focuses on three principal topics: (1) models used for predicting
radionuclide transport, (2) data sets used as bases for prediction, and (3) lack of
uncertainty analysis.
"The Radionuclide Transport Models: The models employed by the ORP to predict the
transport of radionuclides in the environment are often inappropriate. Specific models are
either outdated or are not the best choice for the specific task. During recent years,
improvements in model platform, development, selection and peer review have been
inadequate. [Several examples followed.]
"Data Used for Prediction: The data sets used by the ORP as the bases for prediction of
the effects of proposed regulatory actions are not adequate. They often do not include the
best and most complete information available within the time and budget constraints posed
by specific problems, or by the general needs of the Agency. Sensitivity analysis should be
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used to determine the data sets most in need of supplementation. During recent years the
Committee has found little Office of Radiation Programs support for collection of
adequate data. [Several examples followed.]
"Inadequate Uncertainty Analysis: ORP documents using the results of modeling
generally do not include detailed presentation of uncertainty analyses. The multiple levels
of conservatism often built into a particular analysis are usually not apparent from the
document. Specific results often reflect the high end of a range of possible modeling
results. Rather, a modeling result should in most cases be presented as an average
(reflecting average input data) and a range (which may include a zero health risk at the
low end). Presentation of the range of uncertainty is often helpful to the decision maker.
The Committee has observed improvement in uncertainty analysis in specific cases in
recent years; however, in general, few Office of Radiation Programs reports present their
results properly bounded. [Several examples followed.]
"Finally, given the eventual selection of a suite of appropriate models, adequate supporting
data sets, and development of a well-designed sensitivity and uncertainty analysis protocol,
two more topics must be considered by the ORP.
"1. The selected models must be adequately validated, i.e., their ability to predict
must be tested against actual environmental measurements.
"2. An ordered approach to the selection, from the above suite, of specific models
most appropriate to specific problems must be developed. For example, single,
one-dimensional models are best suited for screening tasks. Given a good
understanding of input/output uncertainty ranges, a simple model may provide an
adequate, cost-effective prediction for many cases. More complex models, with
more complex data requirements, should logically be specified only when the
increased accuracy of resulting predictions is truly required to solve a problem, and
when an adequate input data base is available to support the complex input
requirements of the model.
"In summary, many of the recommendations found in recent RAC reports echo those in
the August 1984 report of the Science Advisory Board Subcommittee on Risk Assessment
for Radionuclides [Appendix A, Report #3] and the SAB generic "Resolution on Use of
Mathematical Models by EPA for Regulatory Assessment and Decision-Making"
(Appendix B, EPA-SAB-EEC-89-012). The ORP has discussed these problems on
numerous occasions in the interim, and has assured the SAB it will develop the techniques
and data sets to allow state-of-the-art risk assessments as the basis for regulation, but
much of the basic framework of problems remains.
"The Committee hopes that by drawing this persistent problem to your attention, specific
work, such as development of validated environmental assessment models with integral
uncertainty analysis capability, will be emphasized. These models must be well-
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documented, peer-reviewed personal computer implementations, capable of producing
uncertainty-bounded best estimates for a range of increasingly detailed input data. They
must be made generally available to other researchers, and should have associated generic
and region-specific input data sets based on research programs. Development of this
comprehensive and defensible model/data set will improve the scientific basis of impact
assessments for the next round of radiation-related regulations."
9.2. Harmonizing Chemical and Radiation Risk-Reduction Strategies
This self-initiated report was prepared and submitted to the EPA Administrator in May,
1992 (Appendix A, Report #34; see also the published literature on this topic, Appendix B, Report
#2). The following summary is taken from the cover letter accompanying the report, with minor
editing.
"The RAC would like to bring to the Agency's attention the need to develop a more
coherent policy for making risk-reduction decisions with respect to radiation and chemical
exposures. The regulation of radiation risks has developed under a different paradigm
than for regulation of chemical risks, and a significant potential exists for EPA decisions
on radiation risk reduction to be seen as unjustified by the health physics community, the
chemical risk management community, or both. Our concern has been stimulated by three
recent reviews that the committee has conducted: the Idaho Radionuclide Study
[Appendix A, Report #28], the Radionuclides in Drinking Water BID [Appendix A,
Reports #26 and#30], and the Citizen's Guide to Radon [Appendix A, Report #29]. In
the first two reviews, the Committee observed that application of the chemical paradigm
to radiation issues was questioned by many in the radiation protection community. The
Agency's treatment of radon in indoor air has been more in line with traditional radiation
risk management, but is inconsistent with the Agency's proposals for control of radon in
drinking water.
"Although the reason for the differences between the two paradigms are historical as well
as scientific, an important feature of radiation risk assessment and reduction is the
existence of a natural background of radiation in the range of 70 to 250 millirem per year
exclusive of indoor radon. With standard risk assessment assumptions, the average
background ... say, 100 millirem per year ... is estimated to produce a cancer risk of
between 2 and 3 per thousand of people over a lifetime of exposure. To many radiation
scientists, reducing excess exposures much below 100 mrem/yr seems unnecessary and in
any case exceedingly difficult to monitor for compliance because it is within the natural
variability of background. By contrast, most EPA programs aimed at reducing risk from
chemical exposures strive for risks of one in ten thousand or lower. When this paradigm
is applied to radiation exposures, such as from radon in drinking water or radionuclides at
Superfund sites, the reduction in radiation exposure is in the vicinity of 3 to 5 percent of
the total exposure, a figure far below the variability of natural background exposures. The
ORP appears to use the radiation paradigm, however, in the case of guidelines for radon
mitigation in homes. The current benchmark criterion for remediation of radon in homes
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is 4 picocuries per liter of air, which translates (again with standard risk assessment
assumptions) to a lifetime cancer risk near one in one hundred.
"The landmark Science Advisory Board report, Reducing Risk: Setting Priorities and
Strategies for Environmental Protection [Appendix B, EPA-SAB-EC-90-021]
(subsequently referred to as Reducing Risk}, clearly enunciates the principle that EPA's
priorities should be directed to reducing the greatest risks first, especially when that can be
accomplished economically. The corollary to that principle is that similar risks should be
treated similarly, which calls for the harmonization of risk-reduction strategies between
chemicals and radiation.
"The resolution to the seeming discrepancy between the radiation paradigm and the
chemical paradigm could be achieved in any of several ways: bringing risk-reduction
strategies for excess radiation exposures consistently in line with the chemical paradigm
(as appears to be happening in some parts of the Agency); bringing chemical risk-
reduction strategies more in line with the radiation paradigm; or creating a synthesis
between the two systems that places more emphasis on what can reasonably be achieved.
In the last case, the importance of background risk could be incorporated and the
balancing of the benefits and costs of risk-reduction measures could be strengthened while
retaining much of the Agency's current approach to chemicals. If none of these
approaches seems appropriate, the Agency should at least explain why the risks from
radiation and chemicals are treated differently under specified conditions. The Committee
appreciates the Agency's difficulty in establishing a coherent risk-reduction strategy under
the variety of statutes governing EPA.
"The ideas in this letter have been discussed with two other SAB committees,
Environmental Health and Drinking Water. While not necessarily in agreement about the
virtues of various approaches to the problem, those committees agree that the issue is
important and should be addressed by the Agency."
9.3. Quantitative Uncertainty Analysis for Radiological Assessments
The following paragraphs are excerpted from the RAC's Commentary submitted to the
EPA Administrator in July, 1993 (Appendix A, Report #41).
"During its history, the Radiation Advisory Committee (RAC) has on numerous occasions
expressed its strongly held view that EPA should incorporate uncertainty analysis as a
routine part of its scientific work. Uncertainty analysis is a necessary element of the
scientific support for policy actions taken by the EPA. The EPA has recently made
significant advance in adopting this practice through the analysis of uncertainties in its
assessment of the risks of radon in drinking water. This joint effort was conducted by the
staff of the Office of Groundwater and Drinking Water, the Office of Radiation and Indoor
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Air, and the Office of Policy and Program Evaluation. This analysis [document] was
recently reviewed by the RAC and was the subject of a separate report (Appendix A,
Report #40). This letter is to provide a commentary on uncertainty analysis and urge its
widespread use.
"Quantitative uncertainty analysis should be an integral part of performing human health
and ecological risk assessments for toxic chemicals, radionuclides, physical stressors, and
biotic stressors. Uncertainties associated with both exposure and effects must be
accounted for in risk assessments and subsequent risk management decisions and
communications. Approaches developed and used by the Offices identified above in their
analysis of quantitative uncertainties associated with radon risks have application to risk
assessment activities in a variety of EPA program Offices.
"Quantitative uncertainty analysis is relatively straightforward when there is reasonable
confidence that the data are of acceptable quality, when crucial relevant risk factors have
not been omitted, and when there is a reasonable well-accepted body of literature on the
parameter values that would be used to define the uncertainties. The tools needed to
accomplish such analysis are readily available.
"Uncertainty analysis is more difficult when data are seriously deficient in quality, when
they simply do not exist, or when important risks have not been studied. A formal
uncertainty analysis must be preceded by an understanding of these factors. ... An
evaluation of the integrity of the data and the sources of information being used to make
both central estimates and uncertainty bounds should be done as part of the analysis.
When there are unquantified risks (such as synergism which can reasonably be expected
but have not been studied), then these should be qualitatively discussed as a complement
to the quantitative uncertainty analysis.
A few of the elements that the Committee believed would aid the EPA in performing the
quantitative aspects of uncertainty analysis are highlighted below.
"Databases exist for many parameters needed for exposure assessments. The Agency
should consider review of distributions of important parameters in criteria and guidance
documents to determine if the information needed to perform formal uncertainty analysis
for particular assessments is present. Bounds on parameter values and the specified shape
of the distribution of plausible values are used in the analysis of uncertainty. Sensitivity
analysis will reveal any important dependence upon the form of the distribution. The
absence of data does not mean that uncertainty analysis cannot be performed. In the
absence of data, quantitative estimates of parameter uncertainties can be obtained by
consulting with an appropriately diverse group of experts. However, in some cases, the
resulting analysis may be controversial externally, especially if the range of expert opinion
is not wide enough.
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"Computer software is available for quantitative uncertainty analysis, both for mainframe
and personal computers. ... Inexpensive ... software has been developed for either
Macintosh or IBM-type computers. Many assessment models can be implemented in
spreadsheet format. ... Of course, whenever using any piece of software, efforts should be
undertaken to benchmark and verify the calculations to ensure that the software is not
producing erroneous results. Efforts should also be made to ensure that the algorithms in
the software are appropriate to the specific environmental problem at hand.
"Several general guides to quantitative uncertainty analysis that are applicable to exposure,
dose, and risk assessment are available [consult Appendix A, Report #41 for specifics].
"The SAB strongly encourages the increased use of uncertainty analysis as exemplified by
its recent use in analyzing the cancer risks of radon in drinking water. The Committee
strongly urges that the EPA incorporate the results of this analysis in its overall drinking
water risk assessment. Additionally it urges that such uses of uncertainty analysis be
expanded to include all EPA programs. In approximately one year the SAB would like to
receive an update on how uncertainty analysis has been used by the Agency across its
programs."
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10. LESSONS LEARNED - EXPERIENCE AND OPINIONS
During its decade of operation, the RAC has evolved and has attempted to evaluate its
own performance as well as its interactions with various parts of EPA, including the Science
Advisory Board. In the sections to follow, these issues - performance and interactions - will be
reviewed and critiqued from the RAC's vantage point.
Broadly, the comments will fall in the categories of the Committee's view of itself, its
interaction with the SAB, dealing with the Agency, and other issues.
10.1 The Committee
The RAC believes that it serves a useful function as a sounding board and monitor of the
EPA's science base on radiation-related issues. Whereas the Committee fully appreciates the
Agency's in-house expertise, a basic principle of the scientific method is the independent
evaluation of the scientific work by peers external to that work. If EPA wants strong science to
develop sound environmental policy, its science, like that of any institution of individual scientists,
must pass through the tests of peer review. The increased utilization of the RAC by the Agency
over the years, and the indications that EPA may increasingly be looked upon as the national focal
point for information and rule-making in radiation matters, have strengthened the Committee
members' conviction that RAC serves an important function and that their own efforts are
worthwhile. Even though the expertise of individual RAC members would make them valuable
participants on other SAB committees, it is as a whole, and through the interactions among the
members, that the Committee achieves its greatest scientific strength.
The RAC itself has evolved over the years, as reflected in its reports to the Agency. The
composition and expertise of the Committee have changed, to accommodate the needs of the
Agency, and in particular those of the Office of Radiation and Indoor Air (ORIA) and its
predecessor, the Office of Radiation Programs (ORP). From an initial, heavily radiobiology-
oriented membership, the Committee has broadened its span, now including more representation
from the physical sciences and engineering.
An issue of great concern to the Committee is the timeliness of the reports submitted to
the Agency. On occasion there has been significant delays before a requested review was
forwarded to the Administrator. Although this has not always been the fault of the Committee
members (see later comment), the Committee has increased its efforts to complete its review
activities in a timely manner.
Looking back over the reports of the RAC and its 1984 predecessor Subcommittees, the
Committee believes that the recommendations submitted to the Agency have been quite
consistent, making allowance for the few cases when advice later had to be modified in view of
developments in the science base. Whereas the bulk of the Committee's reports have dealt with
reviews of background information documents, it may be justified to say that the Committee's
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greatest impact may well have been the result of its self-initiated communications, such as the
ones dealing with residual radioactivity (Appendix A, Report #24), consistency in the treatment of
radon risk from different environmental sources (Appendix A, Report #30), and harmonizing
chemical and radiation risk reduction strategies (Appendix A, Report #34), to mention a few.
Less successful in terms of impact, but equally important in the RAC's opinion, have been the self-
initiated reports on the status of the non-ionizing radiation program (Appendix A, Reports #4,
#14, and #20), and on the status of EPA's radionuclide models (Appendix A, Report #23).
The Committee believes that in order to best serve the Agency, it should, when
appropriate, alert the Agency to the scientific and technical ramifications of various policy
choices. In some of its self-initiated reports, and also in other communications to the Agency, the
RAC has sometimes come close to (and perhaps even crossed) the line separating science from
policy. The interesting point is that in cases in which the Committee has done this, it was orally
commended and was encouraged by EPA Administration members to call attention to apparent
inconsistencies in the Agency's handling of environmental risk factors.
However, the RAC declined a request to review the adequacy of testing for suspected
radioactive contamination at a Superfund landfill. Since this review would have been site-specific
rather than applicable to generic scientific information, the Committee feared that accepting this
charge would set an undesired precedent for reviews of other site-specific problems. [In the case
of another site-specific situation, the Idaho Radionuclide Study which involved exposures to
radioactivity concentrated in slag from elemental phosphorus processing (Appendix A, Reports
#10 and #28), the RAC saw a broader issue embedded in the site specific problem.]
10.2 Dealing with the SAB
The RAC is currently one often standing Committees of the SAB and is dependent on the
SAB staff for administrative support and on the SAB Executive Committee for scientific
oversight. A possible weakness affecting the interaction between the individual Committees and
the rest of the SAB is the relative ignorance on the part of some Committee members in regard to
the SAB's overall scope of operation. Thus, with the exception of the Committee chairs, who
serve on the Executive Committee, few members of the standing Committees are aware of the
activities of the other SAB Committees. Part of the blame for this may fall on the individual
Committee chairs, but more might be done by both the Committee chairs and the SAB staff
(including the DFOs) to inform the Committee members about the overall activities of the SAB.
The SAB staff by and large handles the identification and nominations of members for the
various expert Committees. A greater involvement of the individual Committee members, and in
particular the Committee chairs, in this process might have positive ramifications, both from a
scientific and a psychological point of view.
Perhaps the greatest practical problem in the relationship between the Committees and the
SAB is the periodic shortage, and sometimes unpredictability, of staff support for the preparation
of Committee reports. This has on occasion caused unfortunate delays in the completion of
reports; an extreme example of this was manifested when a backlog often reports by the RAC
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was submitted to the Administrator during the month of January, 1992. This may well have been
the result of Committee overload, but it may also signal a need for more SAB personnel and/or
for a more flexible system of back-up support within the SAB.
Finally, the SAB's budget imposes limits as to the number of Committee and
Subcommittee meetings that can be allocated to the individual SAB Committees. This makes the
decision as to which requests for reviews to accept a critical issue, again a process that might
involve the Committee members to a greater extent than is currently the case.
10.3 Dealing with the Agency
Originally there appeared to be a reluctant acceptance of the RAC by the ORP (later the
ORIA), the EPA operating unit with which the Committee has had its major interaction.
Fortunately, ORP's attitude improved as it was realized that the RAC could be a help rather than a
hindrance to ORP's activities. At times, the Agency had disregarded, and/or disagreed with, the
Committee's recommendations; such disagreements have led to the resignation of two Committee
members who concluded that they were wasting their time giving unwanted advice. In general,
however, the RAC believes that the Agency has valued the Committee's advice in the
overwhelming number of cases and that the Committee's interaction with the program Offices has
been considered beneficial to the Agency. It can be difficult, sometimes, to accept the fact that
the Agency is not required to comply with what a Committee considers scientifically valid advice;
in these situations it is important that the Agency, in its response to the Committee, describe its
reason(s) for not following the Committee's recommendation(s). After an early period during
which the EPA did not regularly provide responses, the Agency has been very conscientious in
acknowledging and responding to RAC reviews.
A potential risk to be guarded against is the assumption, or perception, that a review by an
SAB Committee implies complete endorsement of the document reviewed, which many times is
not the case. Although the RAC is well aware that the Agency, in its decision making, needs to
consider factors beyond the SAB's recommendations, the Committee is still concerned that its role
in such cases will be misunderstood. Reference to SAB review in EPA publications should not be
phrased as to imply complete endorsement by the SAB unless essentially all recommendations
have been incorporated.
To get the most out of the Committee's interaction with the Agency, early information
should be provided about the issues in which the Agency plans to involve the Committee and, to
the extent possible, the Committee should be involved at an early stage of the process, as well as
occasionally thereafter, depending on the complexity or significance of the issue at hand. In the
case of the RAC, any "early warning" is generally accomplished through the periodic meetings
between the Committee chair and the EPA Program or Office Director or her/his representatives.
Early involvement is usually achieved through presentations by Agency staff at the official
Committee meetings but, in a number of instances, the use of the consultation process has been
quite successful. Since the Committee cannot be expected to address every issue that relates to
its expertise (nor is this desirable), it would be useful for the Committee from time to time to be
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informed about issues on the Agency's agenda that it will not be asked to review. To a certain
extent this is already being done in the case of ORIA and the RAC, with the result that the
Committee may be able to view its involvement in the context of the Agency's overall agenda.
In a number of instances, the quality of particular documents, especially when prepared by
outside contractors, has been less than desirable for an efficient review. In the opinion of the
Committee, the Agency should more thoroughly preview contractor-generated documents for
adequacy, thus saving the Committee's time and effort and ensuring a better and more timely
review. Unfortunately, a limited budget and limited time for oversight may prevent such careful
previews from becoming the rule. An additional way to facilitate the Committee's effort is to
make the 'charge' accompanying the request for a review as specific and clearly stated as possible.
10.4 Other Issues
Not only the overall operation of the SAB but also the organizational structure and
functions of the EPA itself may be relatively little understood by the typical RAC member. While
presentations by the ORIA staff allow the Committee members a reasonably good understanding
of the radiation activities of that Office, the connections with other indoor air programs, other
program offices, and the staff offices of the EPA are less apparent. For example, the relationships
of the Office of Research and Development (ORD), and the Office of Policy, Planning and
Evaluation (OPPE) to the radiation programs of ORIA are rarely explained in RAC meetings. In
fact, the Committee has never been requested to review any of the internal radiation research
programs of ORD, such as its early work on the biological effects of low frequency electric and
magnetic fields. Thus, some potential benefits to EPA of Committee thinking appear to have been
missed.
Regardless of whether or not the RAC becomes more widely utilized by the Agency, it
could improve on its current scope by becoming more familiar with the totality of EPA either
through written material or through briefings by staff. Such briefings ought to include information
about how internal and extramural research programs are developed and managed. A better
understanding of these issues might help the Committee in its providing advice to the Agency.
10.5 Continuing Concerns Regarding Issues Reviewed
Among the issues that the RAC has addressed in its history and which the Committee
believes are still important for the Agency to consider are the following:
1) the need to distinguish more clearly between the risk assessment and risk management
aspects of the radiation standards development process;
2) the need for quantitative uncertainly analysis for radiological and other assessments of
risks;
60
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3) the need to highlight the importance of continued development and application of
computer models, especially for radionuclide transport;
4) the need to address risk in a multi-media manner and to maintain a comparative
perspective on risk, even when legislation may not do so;
5) the importance of distinguishing between population and individual risks, as well as
between organ-specific risks versus total cancer risk;
6) the importance of cross-Agency partnerships in addressing radiation concerns;
7) the difficulties resulting from a failure to pursue selected research issues; e.g., radon
mitigation and effects of non-ionizing radiation; and
8) the need to develop a coherent approach for addressing risks from radiation and the
risks from chemicals. (In this regard, the RAC is pleased to see that the Agency has
recently appointed an intra-Agency task force to address this question.)
The need to give continuing attention to some of these issues was reinforced during the
RAC's preparation of its report entitled "Future Issues in Environmental Radiation," (Appendix
A, Report #46; EPA-SAB-RAC-95-006) which has been submitted as the Committee's
contribution to the SAB's Environmental Futures Project. [The futures report has not been
addressed in this retrospective review.]
10.6 Concluding Comments
Some of the comments and suggestions in this section of the report are not necessarily
new, and may well have been discussed in other reports, such as the "Mission and Functioning of
the EPA Science Advisory Board" (See this and related references in Appendix B). Nevertheless,
the RAC felt justified in including in this retrospective report all of the above opinions and
conclusions resulting from its own experiences.
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APPENDIX A - EPA-SAB-RAC REPORTS REVIEWED
1) Pre-RAC Report A Review of Proposed Environmental Standards for the
Management and Disposal of Spent Nuclear Fuel and
Transuranic Wastes (Jan. 1984).
2) Pre-RAC Report B Biological Effects of Radiofrequency Radiation (Letter, Jan.
31, 1984).
3) Pre-RAC Report C Report on the Scientific Basis of EPA's Proposed National
Emissions Standards for Hazardous Air Pollutants for
Radionuclides (Aug. 1984).
4) SAB-RAC (no Nmbr) Non-ionizing Radiation Research Program (RAC-
initiated letter, Apr. 26, 1985).
5) SAB-RAC-86-002 Review of the March 13, 1985 Draft Background Information
Document on Low-Level Radioactive Waste Disposal (Oct.
28, 1985).
6) SAB-RAC-86-005 Emergency Criteria Applicable to Elevated Indoor Radon
Concentrations in Structures Built on the Reading Prong
(Nov. 5, 1985).
7) SAB-RAC-86-028 Review of Proposal Entitled Health Effects of Waterborne
Radon (Sept. 5, 1986).
8) SAB-RAC-87-016 Review of EPA Radon Mitigation Test Matrix (Jan. 12,
1986).
9) SAB-RAC-87-035 Review of the Office of Drinking Water's Assessment of
Radionuclides in Drinking Water and Four Draft Criteria
Documents: Man-Made Occurrences, Uranium, Radium,
Radon (July 27, 1987).
10) SAB-RAC-88-001 Review of Revised Plan for the Idaho Radionuclide
Exposure Study (Oct. 9, 1987).
11) SAB-RAC-88-002 Review of the Office of Radiation Programs' National
Radon Survey Design (Oct. 9, 1987).
12) SAB-RAC-88-009 Review of the Radon Mitigation Research Program
(Dec. 22, 1987).
A-l
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13) SAB-RAC-88-026 Use of the Effective Dose Equivalent Concept (RAC-
Initiated letter, Apr. 27, 1988).
14) SAB-RAC-88-031 Non-Ionizing Radiation Program (RAC-initiated letter,
July 19, 1988).
15) SAB-RAC-88-041 Review of Office of Radiation Programs' Low-LET
Risk Estimate for Regulatory Purposes (Sept. 9,
1988).
16) SAB-RAC-88-042 Review of Office of Radiation Programs' Radon Risk
Estimate (Letter Report, Sept. 9, 1988).
17)EPA-SAB-RAC-89-003 National Emission Standards for Hazardous Air Pollutants
(NESHAP): Standards for Radionuclides -Review of
Assessment Methodologies (Nov. 10, 1988).
18)EPA-SAB-RAC-89-017 Review of the ORP's Radon Measurement Proficiency
Program (Apr. 25, 1989).
19)EPA-SAB-RAC-89-024 Review of the Office of Radiation Programs' NESHAPS
Background Information Document (June 30, 1989).
20) EPA-SAB-LTR-90-003 Non-Ionizing Electromagnetic Fields Research (RAC-initiated
letter, May 4, 1990).
21) EPA-SAB-LTR-91-001 Letter Report on Radon Risk Estimates for General
Population and Smokers, Non-Smokers, and Children (Letter
Rep, Jan. 22, 1991).
22) EPA-SAB-RAC-92-008 Report on Correlation of Short- and Long-term Test Results
for Indoor Radon (Dec. 9, 1991).
23)EPA-SAB-RAC-COM-92-001 Status of EPA Radionuclide Models (RAC-initiated
commentary, Jan. 9, 1992).
24) EPA-SAB-RAC-COM-92-002 Commentary on Residual Radioactivity (RAC-initiated
commentary, Jan. 9, 1992).
25) EPA-SAB-RAC-LTR-92-003 Revised Radon Risk Estimates and Associated
Uncertainties (Letter report, Jan. 9, 1992).
A-2
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26) EPA-SAB-RAC-92-009 Review of the Office of Drinking Water's Criteria Documents
and Related Reports for Uranium, Radon, and Man-made
Beta-Gamma Emitters (Jan. 9, 1992).
27)EPA-SAB-RAC-92-012 Review of the ORP's Design for the National Survey for
Radon in Schools (Jan. 9, 1992).
28) EPA-SAB-RAC-LTR-92-004 Review of Idaho Radionuclide Study (letter report,
Jan. 21, 92; mis-dated 1991).
29) EPA-SAB-RAC-LTR-92-005 Review of Draft Revised Citizen's Guide to Radon
(letter report, Jan. 29, 1992).
30)EPA-SAB-RAC-COM-92-003 Reducing Risks from Radon; Water Criteria Documents
(RAC-initiated commentary, Jan. 29, 1992).
31)EPA-SAB-RAC-92-013 Review of the ORD's Potential Carcinogenicity of
Electromagnetic Fields (Jan. 29, 1992).
32) EPA-SAB-RAC-LTR-92-009 Review of A Research Strategy for Electric and
Magnetic Fields Research: Needs and Priorities
[EPA/600/9-91/016A] (letter report, May 11, 1992).
33) EPA-SAB-RAC-LTR-92-010 Review of the Draft Revised Homebuyer's and Seller's
Guide to Radon (letter report, May 22, 1992).
34) EPA-SAB-RAC-COM-92-007 Harmonizing Chemical and Radiation Risk-Reduction
Strategies (RAC-initiated commentary, May 18, 1992).
3 5) EPA-S AB-RAC-LTR-92-018 Drinking Water Treatment Wastes Containing NORM
(letter report, Sept. 30, 1992).
36) EPA-SAB-RAC-LTR-93-004 Evaluation of EPAs Proposed Methodology for
Estimating Radiogenic Cancer Risk (letter report,
Dec., 1992).
3 7) EP A-S AB-RAC-CON-93 -002 Notification of a Consultation on a Congressionally Mandated
Study of Radon in Water (Jan. 29, 1993).
38)EPA-SAB-RAC-COM-93-001 Radon Mitigation Research: Preliminary Finding (RAC-
initiated commentary, Apr. 16, 1993).
39) EPA-SAB-RAC-COM-93-010 Review of the Release of Carbon-14 in Gaseous Form from
High-Level Waste Disposal (Apr. 29, 1993).
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40) EPA-SAB-RAC-93-014 Review of Uncertainty of Risks Associated with Exposure to
Radon - "Chafee-Lautenberg Multi-Media Risk Study" (July
9, 1993). [cf EC-93-010 (July 30, 1993)].
41)EPA-SAB-RAC-COM-93-006 Quantitative Uncertainty Analysis for Radiological
Assessments (RAC-initiated commentary, July 23, 1993).
42) EPA-SAB-RAC-CON-94-001 Consultation on Cleanup Standards (Dec. 9, 1993).
43) EPA-SAB-RAC-LTR-94-006 ORIA's Radon Measurement Protocol Evaluation
Study (letter report, Jan. 28, 1994).
44) EP A-S AB-RAC-94-013 Review of Diffuse NORM Draft Scoping Document (May 16,
1994).
45) EPA-SAB-RAC-95-XXX Report of the Radon Science Initiative Subcommittee
(RAC-initiated report, 1995).
(NOTE: The RAC Futures Report listed below is referred to, but not reviewed in this report.)
46) EPA-SAB-RAC-95-006 Report of the Radiation Environmental Futures Subcommittee
(1995).
A-4
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NOTE: The above Appendix A report numbers refer to the corresponding section/subsection numbers
below.
1:
4:
7:
10:
13:
16:
19:
22:
25:
28:
6.4
8.1
7.1
• 6.1,
• 3.1,
• 3.2,
•4,9.
• 7.2
• 3.2,
• 6.1,
10.1
5.1
4
.1
5.1
9.2
31: 8.2
34: 9.2
37: 5.5
40: 5.5
43: 7.2
2:
5:
8:
11 :
14:
17 :
20:
23:
26:
29:
32:
35:
38:
41 :
44:
8.1
3.1,
7.2
• 7.4
• 8.1,
• 4,9.
• 8.1,
• 9.1,
• 5.1
• 7.6,
• 8.3
• 5.4
• 7.3
• 9.3
• 6.3
5.1,
10.1
1
10.1
10.1
9.2
3:
6:
9:
12
15
18
21
24
27
30
33
36
39
42
45
4, 9.1
3.2
5.1
7.2
3.1, 6.1
7.2
3.2
6.2, 10.1
7.5
5.1, 5.3, 9.1,
5.4, 9.2, 10.1
7 . 7
3.1
6.5
6.2
7.3
46: 10
.5 (RAC Futures Report - referred to, but not reviewed in this report.)
A-5
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APPENDIX B - RELEVANT REFERENCES
1) Boice, J.D., Jr. and J.F. Fraumeni, Jr., editors, "Radiation Carcinogenesis: Epidemiology and
Biological Significance," Raven Press, New York, 1984
2) Brown, Stephen L., "Harmonizing Chemical and Radiation Risk Management,"
Environmental Science and Technology, Vol. 26, No. 12, 1992, pp. 2336-2338
3) Hansen, David J., "Environmental Protection Agency Sets Blueprint for Revamping R & D
Effort," Chemical and Engineering News. August 8, 1994, pp. 31-32
4) ICRP Publication No. 50, "Risk from Indoor Exposure to Radon Daughters," "International
Commission on Radiological Protection," Pergamon Press, Oxford, 1987
5) ICRP Publication No. 60, "1990 Recommendations of the International Commission on
Radiological Protection," Pergamon Press, Oxford, 1991
6) NAS/NRC, Committee on the Biological Effects of Ionizing Radiation, National Research
Council, "The Effects on Populations of Exposure to Low Levels of Ionizing Radiation:
1980" BEIRIII, National Academy Press, Washington, D.C., 1980
7) NAS/NRC, Committee on the Biological Effects of Ionizing Radiation, National Research
Council, "Health Risks of Radon and Other Internally Deposited Alpha-Emitters: BEIRIV,"
National Academy Press, Washington, D.C., 1988
8) NAS/NRC, Committee on the Biological Effects of Ionizing Radiation, National Research
Council, "Health Effects of Exposure to Low Levels of Ionizing Radiation: BEIR V,"
National Academy Press, Washington, D.C., 1990
9) NCRP Report 78, "Evaluation of Occupational and Environmental Exposures to Radon and
Radon Daughters in the United States," National Council on Radiation Protection and
Measurements, Bethesda, MD, 1984
10) NIH, "Report of the National Institutes of Health Ad Hoc Working Group to Develop
Radioepidemiological Tables," NIH Publication No. 85-2748, U.S. Department of Health and
Human Services, Washington, D.C., 1985
11) Till, John E., Acting Chairman, Radiation Advisory Committee, Science Advisory Board,
Letter to Dr. Norton Nelson, Chairman, Science Advisory Board Executive Committee.
(Letter recommending formation of a group to assist the Administrator in the research
program for radon gas and indoor air quality.), July 3, 1987
12) UNSCEAR, "Ionizing Radiation: Levels and Effects," United Nations, New York, 1972
B-l
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13) UNSCEAR, "Sources and Effects of Ionizing Radiation," United Nations, New York, 1977
14) UNSCEAR, "Ionizing Radiation: Sources and Biological Effects," United Nations, New
York, 1982
15) UNSCEAR, "Genetic and Somatic Effects of Ionizing Radiation," United Nations,New York,
1986
16) UNSCEAR, "Sources, Effects, and Risks of Ionizing Radiation," United Nations, New York,
1988
17) U.S. Congress, Chafee-Lautenberg Amendments, Public Law 102-389; also cited as U.S.
Departments of Veterans Affairs and Housing and Urban Development, and Independent
Agencies Appropriation Act, 1993, Public Law 102-389, Section 519, 106 STAT 1618
(1992) (This is the citation adopted from the Congressional Record that requires the EPA
Study of Radon.)
18) U.S. Congress, Safe Drinking Water Act Amendments of 1986, Public Law 99-339, 100
STAT 642
19) U.S. Congressional Record - Senate, S15103, Sec. 591, "Safe Drinking Water Act
Implementation," September 25, 1992
20) U.S. EPA, Administrator Carol Browner's Report Entitled, "The New Generation of
Environmental Protection, A Summary of EPA's Five-Year Strategic Plan," (This contains
her High-Priority Issues for Environmental Protection), U.S. EPA, Office of the
Administrator, EPA 200-2-94-001, July 1994
21) U.S. EPA, "1987: Guidance to Federal Agencies for Occupational Radiation Protection,"
Federal Register. Vol. 52, No. 17, 1987, pp. 2822-2834
22) U.S. EPA, "Management Review: The Science Advisory Board Staff Office," Office of
Administration and Resources Management, Office of Management and Organization
Division, October 1989
23) U.S. EPA, "National Emissions Standards for Hazardous Air Pollutants: Standards for
Radionuclides," Federal Register. Volume 48, pages 15076-15091, April 6, 1983
24) U.S. EPA, Office of Water, Report to the United States Congress on Radon in Drinking
Water: Multimedia Risk and Cost Assessment of Radon, EPA 81 l-R-94-001, March 1994
25) U.S. EPA, Memo to F. Henry Habicht, II, Deputy Administrator, from Michael H. Shapiro,
Deputy Assistant Administrator, Office of Air and Radiation, entitled "OAR Interactions with
the Science Advisory Board," April 2, 1991
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26) U.S. EPA, Memo on Peer Review, Administrator Browner, June 7, 1994
27) U.S. EPA, Memo on Risk Assessment, H. Habicht, Deputy Administrator, U.S. EPA,
February 26, 1992 (with attachments)
28) U.S. EPA, "National Emissions Standards for Hazardous Air Pollutants: Standards for
Radionuclides," Federal Register, Volume 48, April 6, 1983, pp. 15076-15091
29) U.S. EPA, "Proposed Rule on Radionuclides in the National Emissions Standards for
Hazardous Air Pollutants (NESHAP), Regulation of Radionuclides: Proposed Rule and
Notice of Public Hearing," Federal Register. March 7, 1989, pp. 9611-9668
30) U.S. EPA, Safeguarding the Future: Credible Science, Credible Decisions, EPA/600/9-
91/050, March 1992 (Transmitted to the EPA Administrator on January 8, 1992 by the
Expert Panel on the Role of Science at EPA - Authors are Raymond C. Loehr, Chair; Bernard
D. Goldstein; Anil Nerode; and, Paul G. Risser)
31) U.S. EPA, "Technical Support Document for the 1992 Citizen's Guide to Radon," Office of
Air and Radiation (ANR-464), EPA 400-R-92-011, May 20, 1992
32) U.S. EPA, "Unfinished Business: A Comparative Assessment of Environmental Problems,"
Volume I, Overview, Prepared by Office of Policy Analysis (OP A), Office of Policy, Planning
and Evaluation (OPPE), February 1987
33) U.S. EPA/SAB, "Future Risk: Research Strategies for the 1990's," EPA-SAB-EC-88-040,
September 1, 1988
34) U.S. EPA/SAB, Mission and Functioning Report, "The Mission and Functioning of the EPA
Science Advisory Board." Report to the Board from the SAB Subcommittee on the Mission
and Functioning of the SAB, Final Report Accepted by the SAB Executive Committee on
October 23, 1989
35) U.S. EPA/SAB, "Reducing Risk: Setting Priorities and Strategies for Environmental
Protection," EPA-SAB-EC-90-021, September 25, 1990
36) U.S. EPA/SAB, "Resolution on Use of Mathematical Models by EPA for Regulatory
Assessment and Decision-Making," Report of the Environmental Engineering Committee,
EPA-SAB-EEC-89-012, January 13, 1989
37) U.S. EPA/SAB, Interim response on the SAB review of the Agency's Chafee-Lautenberg
study of the risks from radon exposure and the costs of mitigating such risks, EPA-SAB-EC-
COM-93-003, May 13, 1993
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38) U.S. EPA/SAB, Review of the Office of Groundwater and Drinking Water Approach to the
Costs of Radon Control or Mitigation Experienced by Households or Communities, Report
of the Drinking Water Committee, EPA-SAB-DWC-93-015, July 29, 1993
39) U.S. EPA/SAB, SAB Review of Multimedia Risk and Cost Assessment of Radon in Drinking
water, A Letter Report of the Executive Committee, EPA-SAB-EC-LTR-93-010, July 30,
1993
40) U.S. EPA/SAB, "Uneasy Partners: A History and Analysis of the EPA's Science Advisory
Board," by Perry Bush, Carnegie-Mellon University, August 21, 1989
41) Upton, A.C., R.E. Albert, F.J. Burns, and R.E. Shore, editors, "Radiation Carcinogenesis,"
Elsevier, New York, 1986
42) Yosie, Terry F., Vice President, Health and Environment, American Petroleum Institute, "The
Science Advisory Board: Partner and Critic in the Development and Use of Scientific
Information in the U.S. Environmental Protection Agency, Presented at the Belmont
Workshop on Scientific Advice for Environmental Health Education, October, 1988
43) Terry F. Yosie, "The EPA Science Advisory Board: A Ten-Year Retrospective View," Risk
Analysis. Vol. 8, No. 2, 1988, pp. 167-168
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APPENDIX C - RADIATION ADVISORY COMMITTEE CHARTER
PREAMBLE: The Administrator of the Environmental Protection Agency (EPA) has asked the
Science Advisory Board (SAB) to establish a standing committee on environmental radiation.
The formation of such a committee was recommended by the SAB Subcommittee on Risk
Assessment for Radionuclides as part of its review of the scientific basis of EPA's proposed
standards for airborne radionuclides. The newly-created committee is expected to provide
independent scientific advice to EPA as it carries out its mandated activities.
Objective: To review and evaluate the scientific basis and quality of the Agency's risk
assessments, research, and other scientific activities related to environmental radiation.
Charge: To establish, on a continuing basis, a committee constituted of a group of scientists
knowledgeable in matters related to the impact of radiation on the environment and human
populations. The committee is expected to provide a review of the scientific quality of the
Agency's radiation activities and to offer advice on how its scientific capabilities may be
maintained at a high level. Specifically, the committee is expected to review and comment on the
adequacy of scientific information and analyses used in developing risk assessments and other
scientific documents on radiation matters.
Scope of Activities: Areas of current and planned committee activity include: (1) providing
independent review of scientific analyses used to estimate the impact of radiation on the
environment and human populations for EPA's rulemaking activities; (2) carrying out peer
reviews and providing advice to EPA on the state-of-the-art of evolving dispersion and transport
models and risk assessment methods development; and (3) identifying priority research,
monitoring, and other scientific needs to support regulatory activities.
Procedure: The committee will meet at least twice annually or more frequently, if necessary, to
carry out its assigned responsibilities. It may hold public meetings to obtain scientific information
to assist the committee. The committee will report to the Administrator through the Executive
committee of the SAB.
[Authority for Charter: see Appendix A, Report #3 (Appendix G of the RAC "forerunner report,"
dated August 17, 1984)]
C-l
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APPENDIX D - LIST OF RADIATION ADVISORY COMMITTEE CHAIRS,
COMMITTEE MEMBERS AND CONSULTANTS
Committee Chairs:
1985: Dr. William J. Schull, Director and Professor of Population Genetics, University of Texas
Health Science Center, School of Public Health, Houston, TX
1986: Dr. William J. Schull, Director and Professor of Population Genetics, University of Texas
Health Science Center, School of Public Health, Houston, TX
1987: Dr. William J. Schull, Director and Professor of Population Genetics, University of Texas
Health Science Center, School of Public Health, Houston, TX
[NOTE: During 1987, Dr. John Till, Radiological Assessments Corporation,
Neeses, South Carolina, served as Acting Chair of RAC, during Dr. Schull's
sabbatical to the Radiation Effects Research Foundation, Hiroshima, Japan.]
1988: Dr. William J. Schull, Director and Professor of Population Genetics, University of Texas
Health Science Center, School of Public Health, Houston, TX
1989: Dr. William J. Schull, Director and Professor of Population Genetics, University of Texas
Health Science Center, School of Public Health, Houston, TX
1990: Dr. Oddvar F. Nygaard, Professor of Radiology, Division of Radiation Biology,
Department of Radiology, Case Western Reserve University, School of Medicine,
Cleveland, OH
1991: Dr. Oddvar F. Nygaard, Professor of Radiology, Division of Radiation Biology,
Department of Radiology, Case Western Reserve University, School of Medicine,
Cleveland, OH
1992: Dr. Oddvar F. Nygaard, Professor Emeritus, Department of Radiology, Case Western
Reserve University, School of Medicine, Cleveland, OH
1993: Dr. Genevieve M. Matanoski, Professor of Epidemiology, The Johns Hopkins University,
School of Hygiene and Public Health, Department of Epidemiology, Baltimore, MD
1994: Dr. James E. Watson, Chair, RAC, Professor, Department of Environmental Sciences and
Engineering, University of North Carolina, Chapel Hill, NC
Committee Members -1985:
D-l
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Dr. William J. Schull, Chair, RAC, Director and Professor of Population Genetics, Center for
Demographic and Population Genetics, School of Public Health, University of Texas Health
Science Center, Houston, TX
Dr. Seymour Jablon, Director, Medical Follow-up Agency, National Research Council,
Washington, D.C.
Dr. Terry Lash, Department of Nuclear Safety, Springfield, Illinois
Dr. James V. Neel, Lee R. Dice University Professor of Human Genetics, The University of
Michigan Medical School, Department of Human Genetics, Ann Arbor, Michigan
Dr. Oddvar Nygaard, Professor of Radiology and Director, Division of Radiation Biology,
Department of Radiology, Case Western Reserve University, School of Medicine, Cleveland,
Ohio
Dr. Warren Sinclair, President, National Council on Radiation Protection and Measurements,
Bethesda, Maryland
Dr. Charles Susskind, Professor, Electrical Engineering & Computer Sciences Department,
College of Engineering, University of California, Berkeley, California
Dr. John Till, Consultant, Radiological Assessments Corporation, Neeses, South Carolina
Executive Secretary 1985: Ms. Kathleen W. Conway, Science Advisory Board, Washington,
D.C.
Committee Members -1986:
Dr. William J. Schull, Chair, RAC, Director and Professor of Population Genetics, Center for
Demographic and Population Genetics, School of Public Health, University of Texas Health
Science Center, Houston, TX
Dr. Seymour Jablon, Director, Medical Follow-up Agency, National Research Council,
Washington, D.C.
Dr. Terry Lash, Department of Nuclear Safety, Springfield, Illinois
Dr. James V. Neel, Lee R. Dice University Professor of Human Genetics, The University of
Michigan Medical School, Department of Human Genetics, Ann Arbor, Michigan
Dr. Oddvar Nygaard, Professor of Radiology, Division of Radiation Biology, Department of
Radiology, Case Western Reserve University, School of Medicine, Cleveland, Ohio
D-2
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Dr. Warren Sinclair, President, National Council on Radiation Protection and Measurements,
Bethesda, Maryland
Dr. Charles Susskind, Professor, Electrical Engineering & Computer Sciences Department,
College of Engineering, University of California, Berkeley, California
Dr. John Till, Consultant, Radiological Assessments Corporation, Neeses, South Carolina
Executive Secretary 1986: Ms. Kathleen W. Conway, Science Advisory Board, Washington,
D.C.
Committee Members -1987:
Dr. William J. Schull, Chair, RAC, Director and Professor of Population Genetics, University of
Texas Health Science Center, School of Public Health, Houston, TX [On leave with Radiation
Effects Research Foundation, Hiroshima, Japan.]
[NOTE: During 1987, Dr. John Till, Radiological Assessments Corporation,
Neeses, South Carolina, served as Acting Chair of RAC, during Dr. Schull's
sabbatical to the Radiation Effects Research Foundation, Hiroshima, Japan.]
Dr. Seymour Jablon, Director, Medical Follow-up Agency, National Research Council,
Washington, D.C.
Dr. Terry Lash, Department of Nuclear Safety, Springfield, Illinois
Dr. James V. Neel, Lee R. Dice University Professor of Human Genetics, The University of
Michigan Medical School, Department of Human Genetics, Ann Arbor, Michigan
Dr. Oddvar Nygaard, Professor of Radiology, Division of Radiation Biology, Department of
Radiology, Case Western Reserve University, School of Medicine, Cleveland, Ohio
Dr. Warren Sinclair, President, National Council on Radiation Protection and Measurements,
Bethesda, Maryland
Dr. Charles Susskind, Professor, Electrical Engineering & Computer Sciences Department,
College of Engineering, University of California, Berkeley, California
Dr. John Till, Private Consultant, Radiological Assessments Corporation, Neeses, South Carolina
[Acting Chair, RAC.]
Executive Secretary 1987: Ms. Kathleen W. Conway, Science Advisory Board, Washington,
D.C.
D-3
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Committee Members -1988:
Dr. William J. Schull, Chair, RAC, Director and Professor of Population Genetics, University of
Texas Health Science Center, School of Public Health, Houston, TX
Dr. Seymour Jablon, Director, Medical Follow-up Agency, National Research Council,
Washington, DC
Dr. James V. Neel, Lee R. Dice University Professor of Human Genetics, University of Michigan
Medical School, Ann Arbor, MI
Dr. Oddvar F. Nygaard, Professor of Radiology, Division of Radiation Biology, Department of
Radiology, Case Western Reserve University, School of Medicine, Cleveland, OH
Dr. Keith J. Schiager, Professor, Department of Radiological Health, University of Utah, Salt
Lake City, UT
Dr. Warren Sinclair, President, National Council on Radiation Protection and Measurements,
Bethesda, MD
Dr. Charles Susskind, Professor, Electrical Engineering & Computer Sciences Department,
University of California, Berkeley, CA
Dr. John Till, Private Consultant, Radiological Assessments Corporation, Neeses, So. Carolina
Executive Secretary 1988: Ms. Kathleen W. Conway, Science Advisory Board, Washington,
D.C.
Committee Members -1989:
Dr. William J. Schull, Chair, RAC, Director and Professor of Population Genetics, University of
Texas Health Science Center, School of Public Health, Houston, TX
Dr. Seymour Jablon, Director, Medical Follow-up Agency, National Research Council,
Washington, DC
Dr. James V. Neel, Lee R. Dice University Professor of Human Genetics, University of Michigan
Medical School, Ann Arbor, MI
Dr. Oddvar F. Nygaard, Professor of Radiology, Division of Radiation Biology, Department of
Radiology, Case Western Reserve University, Cleveland, OH
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Dr. Keith J. Schiager, Professor, Department of Radiological Health, University of Utah, Salt
Lake City, UT
Dr. Warren Sinclair, President, National Council on Radiation Protection and Measurements,
Bethesda, MD
Dr. Charles Susskind, Professor, Electrical Engineering & Computer Sciences Department,
College of Engineering, University of California, Berkeley, CA
Dr. John Till, Private Consultant, Radiological Assessments Corporation, Neeses, So. Carolina
Mr. Paul Voilleque, Science Applications International Corporation, Idaho Falls, Idaho
Executive Secretary 1989: Ms. Kathleen W. Conway, Science Advisory Board, Washington,
D.C.
Committee Members -1990:
Dr. Oddvar Nygaard, Chair, RAC, Professor of Radiology, Division of Radiation Biology,
Department of Radiology, Case Western Reserve University, Cleveland, OH
Dr. Kelly H. Clifton, Professor, Department of Human Oncology and Radiology, University of
Wisconsin, Clinical Cancer Center, Madison, WI
Dr. James E. Martin, Assistant Professor of Radiological Health, University of Michigan, School
of Public Health, Ann Arbor, MI
Dr. Genevieve M. Matanoski, Professor of Epidemiology, The Johns Hopkins University, School
of Hygiene and Public Health, Department of Epidemiology, Baltimore, MD
Dr. Keith Schiager, Professor, Department of Radiological Health, University of Utah, Salt Lake
City, UT
Dr. Warren K. Sinclair, President, National Council on Radiation Protection and Measurements,
Bethesda, MD
Mr. Paul G. Voilleque, Science Applications International Corp., Idaho Falls, ID
Dr. F. Ward Whicker, Professor, Department of Radiology and Radiation Biology, Colorado
State University, Fort Collins, CO
Designated Federal Official 1990: Ms. Kathleen W. Conway, Science Advisory Board,
Washington, D.C.
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Committee Members -1991:
Dr. Oddvar F. Nygaard, Chair, RAC, Professor of Radiology, Division of Radiation Biology,
Department of Radiology, Case Western Reserve University, Cleveland, OH
Dr. Kelly Clifton, Professor, Department of Human Oncology & Radiology, University of
Wisconsin Cancer Center, Madison, WI
Dr. James E. Martin, Assistant Professor of Radiological Health, University of Michigan, School
of Public Health, Ann Arbor, MI
Dr. Genevieve M. Matanoski, Professor of Epidemiology, The Johns Hopkins University, School
of Hygiene and Public Health, Baltimore, MD
Dr. Richard G. Sextro, Staff Scientist, Building Ventilation and Indoor Air Quality Program,
Lawrence Berkeley Laboratory, Berkeley, CA
Mr. Paul G. Voilleque, MJP Risk Assessment, Inc., Idaho Falls, ID
Designated Federal Official 1991: Ms. Kathleen W. Conway, Science Advisory Board,
Washington, D.C.
Committee Members -1992:
Dr. Oddvar F. Nygaard, Chair, RAC, Professor of Radiology, Division of Radiation Biology,
Department of Radiology, Case Western Reserve University, Cleveland, OH
Dr. Stephen L. Brown, ENSR Consulting & Engineering, Alameda, CA
Dr. Kelly H. Clifton, Professor, Department of Human Oncology and Radiology, University of
Wisconsin, Clinical Cancer Center, Madison, WI
Dr. James E. Martin, Assistant Professor of Radiological Health, University of Michigan, School
of Public Health, Ann Arbor, MI
Dr. Genevieve M. Matanoski, Professor of Epidemiology, The Johns Hopkins University, School
of Hygiene and Public Health, Department of Epidemiology, Baltimore, MD
Dr. H. Robert Meyer, C.N.S.I., Harrisburg, PA [Now Vice President, Keystone Scientific, Fort
Collins, CO]
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Dr. Richard G. Sextro, Staff Scientist, Building Ventilation and Indoor Air Quality Program,
Lawrence Berkeley Laboratory, Berkeley, CA
Mr. Paul G. Voilleque, MJP Risk Assessment, Inc., Idaho Falls, ID
Dr. James E. Watson, Jr., Professor, Department of Environmental Sciences and Engineering,
University of North Carolina, Chapel Hill, NC
Designated Federal Official 1992: Ms. Kathleen W. Conway, Science Advisory Board,
Washington, D.C.
Committee Members -1993:
Dr. Genevieve M. Matanoski, Chair, RAC, Professor of Epidemiology, The Johns Hopkins
University, School of Hygiene and Public Health, Baltimore, MD
Dr. Stephen L. Brown, ENSR Consulting and Engineering, Alameda, CA [Director, R2C2 (Risks
of Radiation and Chemical Compounds), Oakland, CA]
Dr. June Fabryka-Martin, Staff Scientist, Chemical Science and Technology Division, Los Alamos
National Laboratory, Los Alamos, NM 87545
Dr. Ricardo Gonzalez, Associate Professor, University of Puerto Rico, School of Medicine, San,
Juan, Puerto Rico
Dr. F. Owen Hoffman, President, SENES Oak Ridge, Inc., Center for Risk Analysis, Oak Ridge,
TN
Dr. Oddvar F. Nygaard, Emeritus Professor, Department of Radiology, Department of Radiology,
Case Western Reserve University, Scholl of Medicine, Cleveland, OH
Dr. Richard G. Sextro, Staff Scientist, Building Ventilation and Indoor Air Quality Program,
Lawrence Berkeley Laboratory, Berkeley, CA
Dr. James E. Watson, Jr., Professor, Department of Environmental Sciences and Engineering,
University of North Carolina, Chapel Hill, NC
Designated Federal Officials 1993: Ms. Kathleen W. Conway, and Dr. K. Jack Kooyoomjian,
Science Advisory Board, Washington, D.C.
Committee Members -1994:
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Dr. James E. Watson, Chair, RAC, Professor, Department of Environmental Sciences and
Engineering, University of North Carolina, Chapel Hill, NC
Dr. William Bair (Retired), Battelle Pacific Northwest Lab., Richland, Washington
Dr. Stephen L. Brown, Director, R2C2 (Risks of Radiation and Chemical Compounds), Oakland,
CA
Dr. June Fabryka-Martin, Staff Scientist, Chemical Science and Technology Division, Los Alamos
National Laboratory, Los Alamos, NM 87545
Dr. Ricardo Gonzalez, Associate Professor, University of Puerto Rico, School of Medicine, San,
Juan, Puerto Rico
Dr. David G. Hoel, Chairman & Professor, Department of Biometry & Epidemiology, Medical
University of South Carolina, Charleston, SC
Dr. F. Owen Hoffman, President, SENES Oak Ridge, Inc., Center for Risk Analysis, Oak Ridge,
TN
Dr. Bernd Kahn, Professor, School of Nuclear Engineering and Health Physics and Director,
Environmental Resources Center, Georgia Institute of Technology, Atlanta, GA
Dr. Arjun Makhijani, President, Institute for Energy and Environmental Research, Takoma Park,
MD
Dr. Oddvar F. Nygaard, Emeritus Professor, Division of Radiation Biology, Department of
Radiology, School of Medicine, Case Western Reserve University, Cleveland, OH
Dr. Richard G. Sextro, Staff Scientist, Building Ventilation and Indoor Air Quality Program,
Lawrence Berkeley Laboratory, Berkeley, CA
Designated Federal Official 1994: Dr. K. Jack Kooyoomjian, Science Advisory Board,
Washington, D.C.
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SAB Consultants:
NOTE: The SAB members, when their terms expire, become SAB Consultants, and
some members served as consultants prior to becoming a member. The following list is an
alphabetic compilation of those who served only as consultants, liaisons, or Federal
experts to the SAB's RAC. If a person served at any time as a member, they are listed in
the member listing, and not on the following consultant listing.
1) Dr. Abdul Karim Ahmed, Science and Policy Associates, [and also Community for
National Institute for the Environment (NIE)], Washington, D.C. (EMF Subcommittee)
2) Dr. Julian Andelman, Graduate School of Public Health, University of Pittsburgh,
Pittsburgh, PA (Radionuclides in Drinking Water Subcommittee)
3) Dr. David V. Bates, Professor Emeritus of Medicine, Department of Health Care and
Epidemiology, University of British Columbia, Vancouver, BC - CANADA (EMF
Subcommittee)
4) Dr. Gilbert W. Beebe, (liaison), Health Statistician, Clinical Epidemiology Branch,
National Cancer Institute, Bethesda, MD (Dose and Risk Subcommittee)
5) Dr. Ann Bostrum, School of Public Policy, Georgia Institute of Technology, Atlanta, GA
(Radon Science Initiative Subcommittee)
6) Dr. David Brenner, Centre for Radiological Research, Columbia University, N. Y., N. Y.
(Radon Science Initiative Subcommittee)
7) Dr. Patricia A. Buffler, Ph.D., M.P.H., Dean, School of Public Health, University of
California, Berkeley, CA (EMF Subcommittee)
8) Dr. Craig V. Byus, Associate Professor of Biomedical Sciences and Biochemistry,
University of California, Riverside, CA (EMF Subcommittee)
9) Dr. Douglas Chambers, SENES Consultants, Richmond Hill, Ontario - CANADA (Radon
Science Initiative Subcommittee)
10) Dr. John DiGiovanni, Associate Director, Department of Carcinogenesis, University of
Texas, M.D. Anderson Cancer Center, Smithville, TX (EMF Subcommittee)
11) Dr. William E. Feero, Electric Research and Management, State College, PA (EMF
Subcommittee)
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12) Dr. Thomas F. Gesell, (Liaison), U.S. Department of Energy, Idaho Operations Office,
Idaho Falls, ID (Radionuclides in Drinking Water Subcommittee)
13) Dr. Raymond Guilmette, Inhalation Toxicology Research Institute, Albuquerque, N.M.
(Radon Science Initiative Subcommittee)
14) Dr. John H. Harley, Hoboken, N.J. (Deceased) (Radionuclides in Drinking Water
Subcommittee and Predecessor Review)
15) Dr. Robert Harris, Department of Environmental Science and Engineering (School of
Public Health, University of North Carolina, Chapel Hill, N.C. (EMF Subcommittee)
16) Dr. Clark Heath, American Cancer Society, Atlanta, GA (EMF Subcommittee)
17) Dr. Graham Kalton, Institute for Social Research, University of Michigan, Ann Arbor, MI
(National Radon Survey Review Subcommittee)
18) Dr. Thomas Kirchner, Natural Resources Ecology Lab., Colorado State University, Fort
Collins, CO (Modeling Study Group Subcommittee)
19) Dr. Nan Laird, Department of Biostatistics, Harvard School of Public Health, Boston, MA
(EMF Subcommittee and Radon Measurement Proficiency Subcommittee)
20) Dr. Charles E. Land, (liaison), National Cancer Institute, Bethesda, MD (Dose and Risk
Subcommittee)
21) Dr. Chung Liu, Southcoast Air Quality Management District, El Monte, CA (Modeling
Study Group Subcommittee)
22) Dr. Leonard LoSciuto, Institute for Survey Research, Temple University, Philadelphia, PA
(National Radon Survey Review Subcommittee and Sub sequent Radon in Schools Survey)
23) Dr. Jacqueline Michel, Research Planning Institute, Columbia, SC (National Radon Survey
Review Subcommittee)
24) Dr. M. Granger Morgan, Head, Department of Engineering and Public Policy, Carnegie-
Mellon University, Pittsburgh, PA (EMF Subcommittee)
25) Dr. Mary Ellen O'Connor, Psychology Department, University of Tulsa, Tulsa, OK (EMF
Subcommittee)
26) Dr. Donald Pierce, Department of Statistics, Oregon State University, Corvallis, OR
(EMF Subcommittee)
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27) Dr. Michael Reimer, (Liaison), U.S. Geological Survey, Denver Federal Center, Denver,
CO (Radon Science Initiative Subcommittee)
28) Dr. Donald Schutz, Teledyne Isotopes, Westwood, N.J. (National Radon Survey Review
Subcommittee, and Subsequent Radon in Schools Survey)
29) Dr. Steven Simon, Department of Environmental Sciences, University of North Carolina,
Chapel Hill, N.C. (Sources and Transport Subcommittee)
30) Dr. Alan Siniscalchi, Coordinator of Radon Program, State of Connecticut Department of
Health Services, Hartford, CN (Radon Science Initiative Subcommittee)
31) Dr. Kenneth W. Skrable, University of Lowell, Lowell, MA (Invited Speaker)
32) Dr. Jan AJ. Stolwijk, School of Medicine, Department of Epidemiology and Public
Health, Yale University, New Haven, CT (Radon Risk, Radon Citizen's Guide)
33) Dr. William L. Templeton, Battelle Pacific Northwest, Richland, WA (Sources and
Transport Subcommittee)
34) Dr. James D. Werner, Senior Research Associate, Natural Resources Defense Council,
Washington, D.C. (Invited Speaker on Radiological Waste Issues)
35) Dr. Barry Wilson, Battelle, Pacific Northwest Laboratory, Richland, WA (EMF
Subcommittee)
36) Dr. Richard Wilson, Department of Physics, Harvard University, Cambridge, MA (EMF
Subcommittee)
37) Dr. Rebecca T. Zagraniski (Liaison), Assistant Commissioner, Division of Occupational
and Environmental Health, New Jersey Department of Health, Trenton, N.J. (Modeling
Study Group Subcommittee)
NOTE: There were a number of SAB members or consultants serving on different standing
committees that provided support and liaison activity to the RAC, such as the following (there
were others): Dr. James W. Mercer, President, GeoTrans, Inc., Sterling, VA (EEC liaison on
consultation dealing with Groundwater Modeling); Dr. Arthur Upton, New York University
Medical Center, NY, NY (Dose and Risk Subcommittee), and others.
Previous and Current Secretaries:
Ms. Dorothy M. Clark, Secretary (Served RAC 1984- 1993)
Ms. Diana L. Pozun, Secretary (RAC 1993 to Present)
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SAB Staff Directors:
Dr. Thomas Bath, Staff Director from 1975-1977*
Dr. Richard Dowd, Staff Director from 1977-1981*
Dr. Terry Yosie, Staff Director from 1981 to 1988
Dr. Donald G. Barnes, Staff Director from 1988 to the present
SAB Executive Committee Chairs:
Dr. Emil Mrak (University of California) 1974-1978*
Dr. John Cantlon (Michigan State University) 1979-1981*
Dr. Earnest Gloyna (University of Texas-Austin) 1981-1983*
Dr. Norton Nelson (New York University) 1983-1988
Dr. Raymond Loehr (University of Texas-Austin) 1988-1993
Dr. Genevieve Matanoski (The Johns Hopkins 1993 - present
University)
NOTE: * Denotes SAB Staff Directors and/or SAB Executive Committee Chairs prior to
formation of the Radiation Advisory Committee.
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APPENDIX E - GLOSSARY OF TERMS AND ACRONYMS
A-Bomb Atomic Bomb
AIRDOS-EPA Acronym for a Computer Program (Dosimetry & Modeling)
ALARA As Low As Reasonably Achievable (EPA's Federal Guidance on Popula
tion
Exposu
re)
ARAR Applicable, Relevant and Appropriate Requirements
BEIR Biological Effects of Ionizing Radiation
BID Background Information Document
CAS AC Clean Air Scientific Advisory Committee (U. S. EPA/SAB)
CFR Code of Federal Regulations
Ci Curies (3.7xl010 disintegration per second)
cm Centimeter
COM Commentary (a U. S. EPA/SAB Commentary)
CON Consultation (a U. S. EPA/SAB Consultation)
DFO Designated Federal Official
DOD U.S. Department of Defense
DQO Data Quality Qbjective(s)
DREF Dose Rate Effectiveness Factor
EMF Electric and Magnetic Fields
EPA U.S. Environmental Protection Agency (U.S. EPA, or "The Agency")
ELF Extremely Low Frequency
fj Gut-to-blood absorption factor
FY Fiscal Year
Hz Hertz
ICRP International Commission on Radiological Protection
L Liter
LET Linear Energy Transfer
LTR Letter Report (a U. S. EPA/SAB Letter Report)
m Meter (also milli, as in mrem)
m3 Cubic meter
NAAQS National Ambient Air Quality Standards
NARM Naturally-Occurring and Accelerator-Produced Radioactive Material
NAS National Academy of Sciences
NCRP National Council on Radiation Protection and Measurements
NESHAP National Emissions Standards for Hazardous Air
Pollutants
NIH National Institutes of Health
NORM Naturally-Occurring Radioactive Material
NRC Nuclear Regulatory Commission (also National Research Council - in
reference to NAS and BEIR)
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ODW Office of Drinking Water (U.S. EPA)
APPENDIX E - GLOSSARY OF TERMS AND ACRONYMS: CONTINUED:
OEETD Office of Environmental Engineering and Technology Demonstration (U.S.
EPA/ORD)ORD Office of Research and Development (U.S. EPA)
ORIA Office of Radiation and Indoor Air (U. S. EPA)
ORP Office of Radiation Programs (U. S. EPA - Forerunner of ORIA)
p pico-, [10"12] in combination with specific units
PA Pennsylvania
Po P_olonium, as an element or as an isotope of thorium or uranium alpha-
decay chains (e.g., Po-210)
Q Quality Factor (for high LET radiation)
R Roentgen (unit of exposure)
Ra Radium, as an element or as an isotope of thorium or uranium alpha-decay
chains (e.g., Ra-223, Ra-224, Ra-226)
RAC Radiation Advisory Committee (U. S. EPA/SAB/RAC)
rad Abbreviation for radiation (a unit of absorbed dose of ionizing radiation
equal to an energy of 100 ergs per gram of irradiated material)
RBE Relative Biological Effectiveness
RCRA Resource Conservation and Recovery Act
rem roentgen equivalent man
RF Radio Frequency
Rn Radon, as an element or as an isotope of thorium or uranium alpha-decay
chains (e.g., Rn-219, Rn-220, Rn-222)
RPT Report (a U.S. EPA/SAB Report)
RSIS Radon Science Initiative Subcommittee (U. S. EPA/SAB/RAC)
SAB Science Advisory Board (U. S. EPA)
SARA Superfund Amendments and Reauthorization Act
SDWA Safe Drinking Water Act
Sv Sieyert (equal to 100 rem)
TSCA Toxic Substances Control Act
U Uranium, as an element or as an isotope (e.g., U-234, U-235, U-238)
U.N. United Nations
U.S. United States
UNSCEAR United Nations Scientific Committee on the Effects of Atomic Radiation
|iR/hr micro-Roentgen per hour (see rem)
U.S. United States
U. S. A. United States of America
U.S. EPA United States Environmental Protection Agency (also EPA, or "the
Agency")
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DISTRIBUTION LIST
Deputy Administrator
Assistant Administrators
EPA Regional Administrators
EPA Laboratory Directors
Deputy Assistant Administrator for Air and Radiation:
Director, Office of Radiation and Indoor Air
Director, Office of Radiation Programs
Director, Center for Environmental Research Information (CERI)
EPA Headquarter Libraries
EPA Regional Libraries
EPA Laboratory Libraries
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