REPORT ON THE SCIENTIFIC BASIS OF
EPA'S PROPOSED NATIONAL EMISSION STANDARDS
FOR HAZAIDOUS AIR POLLUTANTS FOE 1ADIONUCHDES
SUBCOMMITTEE ON RISK ASSESSMENT FOR RADIONUCLIDES
SCIENCE ADVISORY BOARD
U.S. ENVIRONMENTAL PROTECT101 AGENCY
AUGUST 1984
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UNITED STATES ENVIRONMENTAL PROTECTION AGENCY
WASHINGTON, D.C. 20460
August 17, 1984
OFFICE or
Honorable William D. Ruckelshaus T« ADMIN,«T*«TOR
Administrator
U.S. Environmental Protection Agency
401 M Street, SW
Washington, B.C. 20460
Dear Mr. Ruckelshaus:
We are pleased to transmit to you the final "Report on the Scientific
Basis of SPA's Proposed National Emission Standards for Hazardous Air
Pollutants for Radionuclides. " This report was prepared, In response to
your request of December 6, 1983, by a Subcommittee of the Science Advisory
Board (SAB). The report was reviewed and approved by the Board's Executive
Committee.
The Subcommittee concluded that the Office of Radiation Programs
(ORP) has generally gathered the appropriate scientific information in a
technically proficient manner for individual elements of an assessment of
the risk of airborne radionucltdes. However, the Subcommittee concluded
that ORP has not assembled and integrated this information in |he format
of a risk assessment that provides a scientifically adequate basis for
regulatory decisions on airborne radionuelides. On the other hand, the
Subcommittee recognizes that the factors SPA must consider in the rulewaklng
process go beyond the scope of this review* Neither EPA nor the public
should interpret these conclusions as representing a Subcommittee position
in favor of or against the proposed radionuclide standards. The charge
to the Subcommittee did not include consideration of the appropriateness
of the standard. It strived to avoid such a consideration and focusedt as
you requested, on the scientific bases and procedures underlying the standard
The report contains six recommendations triilch are directed toward
enhancing the Agency's handling of radiation issues; two of them are
highlighted here. It recommended preparation of an integrated risk
assessment for airborne radioactivity as a basis for making any further
risk management decisions on the airborne radionuclide emissions standard,
including promulgation of a final standard. It also recommended the
formation of a standing committee on radiation within the SAB§ an action
you endorsed at the last SAB Executive Committee meeting.
Preparation of this report on a very complex issue in a short time
period required substantial effort and cooperation from many individuals.
We take this 'opportunity to acknowledge the Input of the many Agency
personnel who contributed to the review process. It was a pleasure to
interact with a number of Individuals sfco demonstrated a. high level of
professional competence on radiation issues.
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. The Board and Subcommittee will be pleased to carry out any further
review of tMs Issue that you may request. We would appreciate receiving
a fotraal response from the Agency on the recommendations and advice
contained In the report.
Sincerely §
Norton Nelson, Chairman
Executive Committee
Roger 0. McClellan, Chairman
SubeomiRiitttee on Risk Assessment
for Radionuclldes
Enclosure
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NOTICE
This report has been written as part of the activities of the Environmental
Protection Agency's Congressionally established Science Advisory Board, a
public group providing advice on scientific issues. The Board is structured
to provide a balanced, independent, expert assessment of scientific issues
it reviews, and hence, the contents of this report do not necessarily
represent the views and policies of the Environmental Protection Agency nor
of other agencies in the Executive Branch of the Federal government.
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TABLE OF CONTENTS
PAGE
I. ' EXECUTIVE SUMMARY 1
II. INTRODUCTION 5
A. Risk Assessment as a Basis for Regulatory
Decision Making .*..**•«»*......*»»»••••• 5
B, Subcommittee Review Procedure ............. 8
C. Major Issues Addressed by the Subcommittee •.....*.*...* 9
D. Outline of this Report 10
III, EVALUATION OF OFFICE OP RADIATION PROGRAM'S APPROACH TO 11
RISK ASSESSMENT FOR RADIONUCL1DSS
A. Subcommittees Evaluation of Individual Elements of
a Risk Assessment for Radlonuelidee 11
1. Source term assessment ........**...*•••..11
2. Dispersion and environmental transport models: s'Owrce to
individuals 12
3. Dose calculation models: dose to individuals
In a population ................••*•••• 19
4. Risk estimation models: individuals and populations 23
B. Use of Risk Assessment in Ru^eniaklng Under Section 112 of
the Clean Air Act ; 29
C. Subcommittee Findings ...........«*..***• ...31
IV, SUBCOMMITTEE CONCLUSIONS AND RECOMMENDATIONS 34
A. Need for a Scientific Issues Staff Paper to Identify and
Evaluate the Scientific Basis for Radiation Ilsk
Management Decisions ..,......*****. .........34
B, Establishment of a Continuing Scientific Oversight Hechanisn to
Review Assessments for Radiation Standards and Other ORP Activities. 35
C. Integration of Risk Assessment Efforts Between the Office
of Radiation Programs and Other Staff Offices Within EPA ...... 36
D. Research Needs ...........................37
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V. APPENDICES
A. Subcommittee Roster
B. Letter from William D. Ruckelshaus to Science Advisory
Board Chatrmtt, December 6» 1983
C, National Emission Standards for Hazardous Air
Pollutants: Standards for ladionuclides, April 6, 1983
D. List of Subcommittee Meetings, Briefings
and Public Presentations
E. References
F. Canparlson of AIRDOS-EPA Predictions With Those of Other Models
and Real Data; Explanation of Table 1 and Figures 1-7
G. Proposed Charge for a SAB Radiation Advisory Committee
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I. EXECUTIVE SUMMARY
At the request of Administrator William D. Ruckelshaus, the EPA's Science
Advisory Board (SAB) formed a Subcommittee on Risk Assessment for Radionuclides which.
has reviewed the methodology used by the Office of Radiation Programs (ORP) in
assessing human health risks from airborne releases of radionuclides. In a distilled
form, the Subcommittee's activities can be viewed as addressing two Interrelated ques-
tions. First, did the Agency's staff collect the scientifically relevant data and
use scientifically defensible approaches In modeling the transport of radlotniclides
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, are the Individual facts,
calculational operations, scientific judgments and estimates of uncertainty
documented and Integrated in a clear and logical manner to provide a risk assessment
that can be used as a scientific basis for risk management purposes, l*e» standards
setting? "'
With regard to the first question, the Subcommittee concludes that ORP__has_
generallyi_gathered_the_ approprlate_s^c_len_t:tfic_lnfgrinatioti in a technically, proficient^
nanner for individual elements of a,, risk assessment. With regard to the second
question, the Subcommittee concludes that ORP has not assembled and integrated this
information in the format of a risk^assessment that provides a scientifically
adequate basis for regulatorydecisions on airborne radionuclides* Neither EPA nor
the public should interpret these conclusions as representing a Subcommittee .position
in favor of or against the proposed radionuclides standards. The charge to the
Subcommittee did not include consideration of the appropriateness of the proposed
levels in EPA's radionuclides eroission standards, presumably because the standards
embody not only risk assessment considerations but also risk management factors such as
the legislative mandate and the cost of control technology to reduce emissions.
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The document which most nearly represents such a risk assessment, but still
stops far short, Is the proposed rule for "National Emission Standards for Hazardous
Air Pollutants: Standards for Radlonuclides, "_Federal Regi_st_er_ Vol. 48, No. 67,
April 6, 1983, pp. 15076-15091. ..The proposed rule Is enclosed as Appendix C. By
its very nature as a proposed standard, this document Includes an interweaving of
scientific facts and interpretation, economic considerations, and social and political
value judgments* A second document, entitled the "Background Information Document;
Proposed Standards for Radlonuclldes," EPA 520/1-83-001 is a useful supplement to
the Federal Register notice* However, even when the proposed standards and the
background document are considered together, they are not sufficiently complete nor
organized to serve as a Scientifically adequate statement of the health risks from
emissions of radlonudides. Because of this deficiency, public debate on the
r* * '
scientific underpinnings of the standard has been blurred with discussion of social,
economic and political considerations. Unfortunatelyt this blurring makes it
difficult to reach agreement or effect changes even vhen they exclusively involve
scientific issues*
For comparison with other scientific activities of the Agency, It is useful to
consider the process used in developing National Ambient Air Quality Standards (NAAQS).
In that process, it has been found appropriate to Include preparation and Science
Advisory Board (specifically, the Clean Air Scientific Advisory Committee) review
of both a criteria document and a staff position paper. The position paper serves
an intermediate step between the criteria document and the risk management functions
of setting NMQS. The staff paper has served to sharpen the analysis and presentation
of the scientific basis of the standards.
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The concept of a staff position paper Is readily transferable to assessing
radiation risks and to defining the use of scientific concepts and data 'for purposes
of developing emission, standards for radionuelides. Such a staff position paper
should Include the conceptual framework for assessing radiation risks starting with
identifying sources of radionuellde emissions, analyzing the movement of radlonuelidies
<*
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 endpolnts.
These estimates should then be compared to available Information on incidence of
cancer and genetic risks in the population that EPA attributes from other well-recognized
environmental, social and occupational factors*- It wight also be appropriate for
this position paper or a complementary document to identify various potential
levels of a standard(s)» noting for each level if compliance could 1>e established
by direct measurements or only indirectly by modeling. A presentation of this type
would provide the scientific input needed by the risk manager to arrive at a reasonable
and scientifically defensible standard(s).
In the case of the current proposed emissions standards for airborne radlonu-
clides, a staff position paper was not prepared and the Subcommittee Is uncertain
as _to how and to what extent the scientific data base w^sused^ to set the ..standard.
It is also apparent that neither the scientific community In general nor the Science
AdvlBory__Board_was_a_sked to review thoroughly ORP's use_gf_sc_ientlflc data In early
stages of the radlonuclide standards development process.
To improve the scientific basis for regulatory decisions on radiation issues,
the Subcommittee recommends a number of actions. These includet
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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
Includes development of a risk assessment document which makes reference,
as appropriate> to more detailed analyses found In the scientific literature-
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 & part of the EPA 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.
5) that procedures be developed for soliciting and receiving public comment
and SAB review on radiation risk assessments before proposed standards
are developed.
6) that steps be taken Co enhance communication between the Office of Radiation
Programs and other staff offices of the Agency and the scientific connaunity
on Issues related to risk assessment.
The first five recommendations are consistent with procedures used by a number
of offices within the Agency for assessing risks from other types of pollution and
soliciting SAB and public input. The sixth recommendation is designed to ensure that
maximum advantage Is taken of the diverse kinds of expertise and experience that
exist in the Agency and the Scientific community which can be brought to bear on
QRP activities. This recommendation is also developed to ensure that the expertise
of ORP personnel can have a favorable impact on other offices within the Agency
that prepare risfc assessments in support of regulatory decisions.
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II. INTRODUCTION
This is the final report of the EPA Science Advisory Board's Subcommittee on
Risk Assessment for Radlonuclldes. The Subcommittee was established by the SAB
Executive Cotsmittee on December 9» 1983, in response to an official request from
Administrator William D« Ruekelshaus on December 6, 1983. The membership of the
**
Subcommittee is presented in Appendix A*
The charge to the Subcommittee, as stated by Administrator Ruckelshaus, is
to 1) "review the scientific basis of the risk assessments used to develop stan-
dards for protection from radionudides In the environment*" The Stibcoaoittee
interprets this activity as applying specifically to those source categories
subject to EPA*s rulemaking carried out under the authority of Section 112 of the
Clean Air Act. 2) The Administrator also requested the Subcommittee to "critically
review the process by which the Agency estimates human cancer and genetic risk
due to radionudides in the environment ... (including] examination of the methods
used to estimate the transport of raetlonuelides 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." The objective
of the review is to determine whether EPA "has proceeded in a reasonable and
scientifically sound way" in developing risk estimates for radionuclides. A set
of ten questions prepared by the Office of Radiation Programs accompanied the
Administrator's request* A list of the questions and Mr* Ruckelshaus1 letter are
included in Appendix B.
A. Risk Assessment as a Basis for Regulatory Decision Making
The compilation and assessment of scientific data by regulatory agencies for
the purpose of developing standards for the control of emissions from various source
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categories to reduce human and environmental risk is a subject that "has generated
a great deal of discussion. Many proposals have evolved on how to present scien-
tific data for use by policymakers in carrying out statutory oandates- Two re-
cent attempts to define a framework for compiling and assessing scientific data
in the ruleraaklng process were those articulated by the National Research Council
in its March 1983 report entitled Risk Assessment in the Federal Government;
i **
Managing the Process,** and by EPA Administrator Ruckelshaus in speeches to the
National Academy of Sciences ia June 1983^ and to the Alusini Society of Princeton
University in. March 1984,3
A common theme of these efforts is the need to separate issues related to
the assessment of risk from those associated with the expression of social, eco-
nomic , and political values which determine strategies for managing risk. An
example of this distinction is the following; a technical assessment of the
human health risk from radionudides would address such issues as the relationships
involving movement of radionuclldes from a source through environmental pathways
to a dose received by human populations to an estimation of the probability of a
health effect occurring. This part of the process would also include a conparison
of the calculated risks from other environmental, occupational and societal factors.
A policy decision on how to manage the calculated risk would use the findings of
this assessment effort in connection with a definition of acceptable risk (as
established by the statute or by other means), consider the available methods of
reducing exposures through, for example, control technologies and economic incentives,
and corapute the costs to society of regulating at various levels of residual risk.
As a general framework, the Subcommittee endorses the distinction between
the scientific practice of assessing risk and the socio-political task of
References In this report can be found in Appendix E.
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choosing among regulatory options to manage risk* However, as the Subcommittee
proceeded through It* review of the ORP's documentation for assessing risks from
radionuclide sources, it was obvious that the risk assessment/risk management
framework is more of a continuum than a dichotomy*
This continuum exists for the airborne radionuelides rulenaking for at least
five reasons* One is that the «risk assessment phase of the regulatory process is
not value free. This Is the case because the facts required to develop a risk
assessment are rarely incontrovertible. Thus, value judgments, albeit scientific,
must "be nade as to which facts should be used in the risk assessment. Second,
EPA does not currently have a program-specific, operational definition of the
distinction between risk assessment and risk management. As a result, it is not
clear that standardized terns of reference have been applied or that consistency
of approach has been realized. Third, In the process of risk assessment, raany
assumptions must be nade. Scientists may be swayed In their choice of assumptions
j
by their underlying regulatory philosophy. The choice of a linear non-threshold
dose-response relationship compared to a linear quadratic or other relationships
is a good case In point. As evidenced by the National Acadeiay of Science's third
report on Biological Effects of Ionizing Radiation (BEIR III), knowledgeable
Scientists disagree on which dose-response relationship is best. Some of them
favor the linear non^threshold relationship primarily because, in an area of
uncertainty, they would prefer to choose the approach which yielded the higher
calculations of risk. Others hold the opposite view. Fourth, and most importantly,
the format In which the Subcommittee was asked to evaluate radlonuclide risks
commingled the risk assessment and risk management phases. At the time the
Subcommittee was asked to begin Its review of of the scientific data base, the
formal rule had already been proposed in the Federal Register on April 6, 1983,
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8
This Kteant that the Agency had already completed tts evaluation of human health
risks froci airborne radionuclldes an
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literature reviewed and/or developed by OM.P staff, estimates of cancer deaths and
genetic risks from radionuclide exposures, technical briefings provided to senior
EPA decision-makers, and case studies of two source categories—the elemental
phosphorus plant In Pocatello, Idaho, and the 1-12 facility at Oak Ridge National
Laboratory—to Illustrate the application of the methodology. The briefings were
extremely helpful in enabling the Subcommittee to understand the technical issues
under consideration and ORP's approach toward risk, assessment. Agency staff were
particularly cooperative in responding to the Subcommittee's questions and Its
requests for information. A list of Subcommittee'meetings, briefings and public
presentations Is .included in Appendix D»
C, Major Issues Addressed by the Subcommittee
As noted previously, the Office of Radiation Programs submitted ten questions
for the Subcoramittee's review. In general, the questions capture many of the com-
ponents of the scientific analysis needed In a risk assessment, but they alone do
j*'«'
not constitute a risk assessment. Therefore, this report Includes not only the
Subcommittee's response to ORP's questions, but it also presents the panel's
judgment on the adequacy of the overall process utilized by ORP in evaluating
scientific data and developing a risk assessment for this rulecsakiag activity.
A key assumption made by the Subcommittee throughout its review was the belief
that EPA's risk management decisions should be based on the scientific evaluation
by the ORP staff of the probable risk that would result from exposure to airborne
radionuclides* Difficult as this assessment may be, it Is believed to be
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preferable to alternatives such as use of am ALARA* approach where the recommended
standard is determined by the minimum exposure that nay be reasonably achieved. It
Is the opinion of some, but not the majority of Subcommittee members that the ALAEA
concept should be vigorously applied as part of a strategy to minlniai* exposure and
risk. However, the use of such a strategy must not be substituted for development
of an integrated risk assessment ""that can be used as the cornerstone of development
of the standards*
D* Outline of this Report
The body of this report consists of two major sections. Section III evaluates
the approach employed by the Office of Radiation Programs in assessing human health
risks from airborne radionuclides. The Subcommittee identifies the individual ele-
ments of a risk assessment for radionuclides, discusses the strengths and weaknesses
of the ORP approach, evaluates the process for preparing health risk assessments
for hazardous air pollutants within GRP compared with other EPA staff offices, and
presents its key findings. The major conclusions and recommendations of the Subcom-
mittee are presented in Section IV. These address the need for a scientific issues
staff paper to Identify and synthesize the scientific data base for an integrated
health risk assessment used for standards development! establishment of a continuing
scientific oversight mechanism to review ORP scientific activities. Including the
development of risk assessments for radiation standards? enhanced coordination
*ALARA is an acronym for As Low As Reasonably Achievable. It is a concept that Is
ail outgrowth of the hypothesis that there Is no threshold for the carcinogenic or
genetic effects of Ionizing radiation arid that any dose, however small* Increases
the probability of such effects, which becomes small as the dose approaches the
natural radiation background. An inherent problem with the ALAM concept lies in
the subjectivity of the word "reasonably." No EPA policy has been formulated to
define the word "reasonably" in this context. In this connection, the panel noted
early In its deliberations, that the health Impacts from radioactive emissions
currently being discharged from all the U.S. facilities (other than coal-fired
boilers) covered In the Background Information Document EPA 520/1-83-001 were
calculated to be much less than one cancer per year for the entire country. This
estimate should assist policy makers to judge whether ALARA is currently being
achieved, and may also assist in deciding the relative priority that concerns
about radioactive emissions should receive, relative to other matters that must be
dealt with by EPA.
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of risk assessment efforts between 0RP and other offices within EPA, and some o^jor
research needs. An Executive Summary of the Subcommittee's major conclusions and
recommendations Is provided In Section I.
III. EVALUATION OF OFFICE OF RADIATIONPROGRAMS APPROACH TO RISK ASSESSMENT FOR
RADIOCTJCUDES
A scientifically defensible risk assessment for radlonuclides should address at
least five major elements* These"" include 1) identification of the significant nan-made
or technologically enhanced sources of radionuclldes; 2) a description of the
movement of radionuclldes from a source through environmental pathways to peoplej
3) calculation of the doses received by people; 4) estimation of genetic or soaatic
health effects; and 5) incorporation of estimates of uncertainty into elements 1-4
thereby enabling development of upper, central and lower estimates of health risks,
for releases of small quantities of radlotmclides. It Is important that the uncertainty
associated with the risk estimates consider all elements of the relationship from sources—->
transport —~> dose —v* effects and not concentrate excessively on the relationship
between dose and effects. It is quite likely that the scientific uncertainty associated
with the relationship of sources —? transport —-^ dose are greater than those associated
with the relationship between dose and effect.
The Subcommittee has evaluated the OS.P approach to risk assessment for radlomi-
clides using this conceptual framework presented above* Within each element of this
framework^ a statement of the strengths and weakness of OEP's efforts are presented.
In addition, responses to the ten ORF questions listed in Appendix B are given in
the following section of the report*
A. SUBCOMMITTEE EVALUATION OF INDIVIDUAL ELEMENTS OF A RISK ASSESSMENT FOR
MDIONUCLIDES
1* Source terra assessiuent
The Identification of sources that are significant emitters of airborne radionu-
clides, and an estimation of the quantities of such emissions, is a major input para-
meter in the process of calculating probable human health effects.
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To understand better how ORP assessed radiomiclide emission sources and the relationship
between airborne releases and human exposures, the Subcommittee requested briefings
on specific source categories- Two briefings were presented. The first was for
the Y-12 nuclear weapons facility at Oak Ridge National Laboratory and the other
was for"an elemental phosphorus plant in Pocatello, Idaho. The briefings aided the
Subcommittee in understanding how ORP applied its AIRDOS-EPA air dispersion model
to estimate radionuelide concentrations In the neighborhood of a source and dose
rates to a population within a larger region- The release values for the 1-12
facility were provided to the EPA by the Department of Energy. Detailed information
was not submitted as to how the release values were established nor their validity
for projecting future releases. For the Pocatello site both site-specific monitoring
data and calculated release values were available* Although the measured and
estimated values were not in perfect agreement, the fact that they were within a.
factor of two to three did provide for greater confidence in the values than the
case where only estimates were available. The Subcommittee concluded that ORP
presented a clear statement of this element of the risk assessment chain. However,
the Subcommittee felt there was a continuing need to further validate estimates
when site specific data are not available and to establish the utility of data on
past releases as predictors of future releases.
2. Dispersion and environmental transport models z source to individuals
ORP Question 9s Are the air dispersion models reasonable to estimate
radionuelides concentrations 1) in the neighborhood of a
source, and 2) to regional populations?
The basic model used by EPA for calculating the air dispersion of radionu-
elides is AIRDOS-EPA. This computer code includes-a conventional, state-of-the art
air dispersion model, developed for ORP by the Oak Ridge National Laboratory. It
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13
Incorporates standard meteorological observations together with parameters derived
from the existing "body of experimental atmospheric diffusion data by means of the
widely accepted Gaussian plume assumption. It is a flexible, modular, and highly
parameterized model, capable of addressing a wide range of air dispersion problems,
from radionucllde concentrations in the neighborhood of a source to regional population.
exposures at greater distances. Details of the modeling nethodology can be fouad
in the handbooks by Turner^ Haima,"-et al«»^ and in a brief summary by Gifford.^
The performance of AISDOS-EPA its estimating air concentration levels has been
found to compare well with that of other diffusion models of the Gaussian plume
type. The level of uncertainty associated with this class of radionuclide transport
jj n
and dispersion models was summarized by Crawford and Little and Miller*'
In the case of long—terta average concentrations (a month or more) over flat terrainj
and where strong plume buoyancy Is not a significant influence, It ranges from a
factor of about two for nearby receptors to a factor of four for more distant
receptors. These factors can increase to an order of magnitude or more for short~term
j.'
averages (an hour) and for strongly buoyant plumes such as those Iron a power-plant
stack. Corresponding factors over rough terrain are essentially unknown but are
certainly even larger*
How well AIRDOS-EPA performs in a particular modeling application—whether its
actual perforraance level falls, for Instance, within the above limits—depends
primarily on the quality of the many data and parameter inputs that are required to
operate the model, as well as on the correct resolution of various modeling details.
For example, are the input meteorological data, which are often available only for a
somewhat remote airport site, adequately representative of source area meteorological
conditions? Is the AISDOS-EPA plume-rise model, and related assumptions concerning
mixing depth^ correctly applied? How are caliti winds to be dealt with, since wind
speed occurs in the denonlnator of the air-concentration formula? Have conservative
assumptions been cascaded to the point of unrealista?
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These, and other, similar questions have foraed the basis for criticisms of
some of ORP's applications of AIIDOS^EPA. The Subcommittee believes that AIRDQS-EPA
Is a good, useful model, capable of addressing a wide range of air dispersion
problems* It seems inevitable, however, that honest differences of opinion with
the ORP staff related to various modeling details will continue to arise as the
model is applied in regulatory proceedings. This natural tendency is exacerbated
by the complicated structure of models like AIRDQS-IPA. The Subcommittee cannot, of
course, resolve such differences during its current, limited review. The Subcommittee
encourages ORP to present such models In as simple a docuiaented format as possible
with a view to their being understandable to those who would desire to critique the
calculations taade with the codes. The Subcommittee also sees the need for soTue
form of continuing, technical review of modeling applications, on a case-by-case
basis, until a better scientific consensus is reached.
ORP Question 10; Is the selection of transfer factors and other
parameters in the food chain analysis reasonable?
The EPA methods in this area are appropriate and probably do not overestimate
or underestimate the doses received beyond the inherent limits inposed by the
current state of our knowledge of this complex area*
The portion of AIRDQS-EPA reviewed that addresses this question begins with a
calculation of the deposition rate to the agricultural ecosystem from a computed
ground-level air concentration and ends with a predicted ingestion rate for radionuclides
by human receptors. These calculations are primarily embodied in the subroutine
DQSEN. DOSEN Is not a computationally large fraction of AIRDOS-EPA, but the rather
significant inherent uncertainties within It account for a major portion of the
overall uncertainty in the total risk assessment equation*
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The mathematical routines within DOSEN are designed to yield steady-state,
time averaged, deterministic predictions of radionuelide concentrations in anitnat
forage and certain human foodstuffs per unit of deposition rate. The concentrations in
foods are multiplied by food consumption rates to yield radionuelide Ingestion
rates by food type* These rates are summed over all food types to yield estimates
of total ingestion rate for individual radionuclides. Corrections for the sources
•f,
of the foods and radioactive decay during storage are included. The formulations
were developed from those used In earlier models, especially the HESMES computer
code^« They are essentially the same as those used In U. S. Nuclear Regulatory
Guide 1.109*11 The only readily apparent differences between AIRDOS-EPA and
these earlier codes are in the choice of certain parameter values.
a. Apparent strengths of the environmental transport
Methodology
The deposition through Ingestion sections of AIRDOS-EPA are based on relatively
simple and straightforward formulae which are well documented. With some exceptions
noted later, the formulations embodied in the relevant subroutines account for the
major processes which normally affect the transport of radionuclides through terres-
trial foodchalns* They are generally accepted and used routinely by many groups
throughout the world* They are designed to utilize a large body of experimental
data which nay be found In the open literature. The choices of parameter values
generally appear to be reasonable and based on the relevant scientific literature.
The model is generic itt tine and space, and thus. It should have broad applicability.
With the help of literature provided by Dr. Owen Hoffman of Oak Ridge National
Laboratory, the Subcommittee wade a comparison of AIRDOS-EFA with other models,
with some limited observed data, as well as with a model called PATHWAY. This latter
model has been tested extensively against real observations (see Table 1) but has
not yet been published In the peer reviewed literature. However It has been presented
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Table 1. Radiomielides Concentrations in Pasture and Foods: A Comparison Between
AIRDOS-EPA and PATHWAY, Units Are Ci-day/kg Per Ci/sq m Deposited.*
Basis '
AlRDQS-EPA(p)
PATHWAY (p:a)
PATHWAY (px5;b)
UNSCEAR (o)
PATHWAY (p/o)
#data sets
#data points
pasture
Cs-137
37
30
150
0*93
2
196
vegetables meat
Sr-90 Cs-137
17 8
11 4
28(c) 20
2.4
0.54
3
46
1-131
1.0
O.I
0.5
1.2
7
160
milk
Cs-137
3.2
1.7
8.5
2-16
2.7
10
737
Sr-90
2.8
0.3
1.5
1.4
2.0
8
527
PAT WAI (p*o/p)
161
37
0,4
3.1
0.8
CONCLUSION,
AIRDOS-EPA
Overptedicts
Underpredicts
x4
x7
x2-4
Note: p -prediction of model
o -real observations
a -time-averaged value
b -values multiplied by five to account for higher
vegetation interception of small particles
c -value multiplied by 0.5 to account for washing loss
*See Appendix F for a detailed explanation of this table.
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17
at scientific conferences and been published in conference proceedings. Based on
these comparisons, it appears that concentrations of important radionuelides in
basic foods as predicted by AIRDQS-EPA are likely well-within order of magnitude
accuracy, and In most cases within a factor of two to five. This encourages the broad use
of the EPA methodology for general assessment applications. There appears neither
i.
a general tendency for the foodchain portion of AIRDOS-EPA to be under-conservative
or over-conservative.
b. Apparent weaknesses of the environmental transport methodology
The Subcommittee raises several questions about the basic structure of the
food chain section of AtRDOS-EPA. For example, the processes of resuspension,
ralnsplash, absorption of surflcial deposits into foliar tissues, and soil ingestion
by beef and dairy cattle do not seem to be Included In the code. Furthermore,
several basic human food types are not explicitly modeled, such as fish, cheese,
poultry, eggs, and red meats other than beef. These omissions do not appear to be
offset by higher human consumption rates of similar foods modeled directly. The
effects of neglecting these processes and specific food Items are not clear In the
absence of a sensitivity analysis designed to test for such effects. This raises
the question of geographic and temporal differences wherein, for example, resuspen-
sion may only be Important in arid or semi-arid regions during dry, windy periods.
AIRDOS-EPA appears to be structured to average across seasons since process
parameters are held constant through time. This practice disregards the significant
seasonal fluctuations in processes such as plant growth, cattle feeding, and sources
of human foods* This simplification leads to wide fluctuations in the degree of
conservatism in dose estimates obtained from AIRDOS-EPA, depending on the season
of the year that releases might occur. This Is potentially a greater problem for
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18
short-lived radionuelides such as 1-131 than for longer-lived substances such as
Sr-90 or Cs-137. A further limitation of this constant-parameter, steady-state
model becomes clear if it is applied to radionuellde releases which are short-term,
time-variant, or sporadic.
Other weaknesses of the Methodology Include the failure to consider particle
size dependency of the fraction of radlonuelides Intercepted fay vegetation and the
absence of documentation on either the scavenging rate or the geological removal
rate.
Probably the greatest weakness of AIRDOS-EPA and similar computer codes is the
lack of validation. The accuracy of prediction Is not well-know, nor is the
degree of uncertainty. Since such a large number of variable parameters are inherent
in complex foodchain models. It does not seem productive to debate at length their
Individual values. It Is the relative accuracy of the final result for the application
intended by EPA which is the chief concern. The very limited coeparison of AIRDQS-EPA
to other models and to real data (see Table 1; see also Explanation of Table 1 and
Figures 1-7 in Appendix F) suggests that the EPA methodology Day be subject to
slight (x5) widerprediction In some cases (e.g., Cs-137 in pasture and meat).
Superimposed on this situation Is the likelihood, based on experience with the
PATHWAY model, that such estimates carry uncertainties on the order of a factor of
four in either direction (GSD-2), This suggests the small but real possibility of
an underprediction by a factor of five x four which could lead to a significant
error in the overall risk estimate. However, over-predictions of the same magnitude
seem equally likely.
While AIRDOS-EPA appears reasonable for approximations of the dose under
generic conditions, the methodology could possibly yield predictions for specific
locales and scenarios of unacceptable accuracy and uncertainty. Thus, without
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19
further testing and possible improvements In the structure of the computer code,
any application of the SPA model to specific problems should be aade with great
care, and appropriate caveats should be stated*
3* Dose calculation models J dose to individuals in a population
ORP Question 8: In a few cases EPA has used organ transfer factors for
a general population rather than those for occupational
workers. Are these changes appropriate and justified
In the documentation?
The uptake factors for the most part are taken from the International Council
on Radiation Protection's (ICRP) estimates, and this is scientifically reasonable*
However, for the transuranle radionuclldes, othet values were used that were based
on GRP's "Proposed Guidance on Dose Limits for Persons Exposed to Transuranium
Elements in the General Environment" (EPA 520/4-77-016, 1977). ORP apparently took
specific values from a letter written by Bair and Thompson of the Battelle Pacific
Northwest Laboratories (pp* 218-220 in "Response to Comments: Guidance on Dose
s*
Limits for Persons Exposed to Transuranuim Elements In the General Environment",
EPA 520/4-78-010, 1978). The draft document entitled "RAD1ISK/BEIR-3, Part
II! Dosimetrlc Methods and Codes Used to Assess Radiation Risk" also notes that the
new f]_ values adopted by the National Radiation Protection Board (NRPB) are closer
to the EPA values than to those of the ICRP.12 The ORP did not provide the NRPB or
ICRP values, however.
The three sets of data are summarized in Table 2, The values shown under
EPA are the Subcommittee's current understanding of what ORP used. At different
times. In material received from different individuals within EPA, the Subcommittee
received different values* This emphasizes the need for better documentation so It will
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Table 2, Comparison of Values for the Gastrointestinal Absorption of Transuranic
Radionuclides (fraction absorbed)
Element
Plutonium
oxides, hydroxides
other forms
biologically incorporated
Other transuranicsc
ICRP3
5 x icr4
5 x ID"4
EPA
10-5
ID'4
*«-
10~5 10~4 or 10-3
5 x 10~4 ID""3
5 x 10-3
10-3
Child (0-12 nos)
Plutonium
oxides, hydroxides
other forms
biologically incorporated
Other transuranicsc
5 x W™4 10-2
5 x 10-3
5 x ]
5 x 10~3
10-2
For workers, fron ICRP, Publication 30, Pt. 1. (1979).
For the public, from Harrison, Had. Protect, Dostoietry 5, 19-35
C O IT V- M^ Pujj X1 *w" f Iik^U I iCi 1_ i_ J, -"^_* I t f 1 SC3\ J.+ L k I^r S-^-.^-r i_ + fcn-^
c NRPB values are for americiurt! arrf curium, only.
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21
be clearer to all concerned as to what was actually done. The values adopted by
EPA are very conservative and this was noted in the 1977 letter from lair and
Thompson. As the stated goal of the EPA Is to provide a best estimate of dose, it
would seen more reasonable to adopt the NRPB values that are based upon a more
recent review and analysis of the literature.
QRP Question 7: Is the choice of ICRP dosimetric models scientifically
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22
Latency period and RBE factors for low (1) and high (20) LET radiation are also
included. The result for somatic effects is a RISK EQUIVALENT FACTOR
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23
2. The documentation for AIRDOS-SPA also indicates that a constant absolute
humidity value of 8 g/m* is used* As the tritium nodel uses the specific activity
approach, the calculated dose is inversely related to absolute humidity. Since
absolute .humidity is typically much lower than 8 g/nr in. much of the U.S.,
this assumption, leads to an underestimation of dose* It would be more appropriate,
and not difficult, to use site specific values for absolute humidity*
3. The physiological nodels and other input data required for the calculation of
dose for internally absorbed radionuclides is equally important, and in many areas
the data are incomplete* EPA should support work aimed at expanding the technical
basis for many of the input parameters*
4. These three calculational programs do not now consider the important factor
of uncertainty in each of the input parameters. The Subcommittee does not
have specific suggestions as to how such data could be included, but believes
that It is important for the EPA to develop methods that would indicate to
the user the uncertainty or "noise" in the final values of REF. This uncertainty
plays an important role in the setting of standards*
5. Although scientifically sound» the units of 1EP are difficult for the lay-
person, or even the scientist, to grasp. Alternatively, consideration might be
given to developing and using a common, unit of risk that could apply to all
radiation hazards and be more readily understood.
4, Risk estimation models : individuals and populations
ORP Question If Has the EPA Office of Radiation Programs considered and
interpreted in a scientifically adequate manner the
appropriate literature on radiation risk assessment including
data sources on radiation risks?
The OlP made available to the Subcommittee a voluminous body of data and
literature related to health risks from radionuclides as well as a typical printout
of DARTAB, the program that estimates population health effects* From its perusal of
such information, the Subcommittee concludes that ORP staff identified the appropriate
scientific basis in evaluating this fora of radiation- It is also clear that» for
some individual elements of the risk assessment (dose calculation models, for example),
generally sound scientific judgment was utilized. The major shortcoming of ORP's
analysis, however, was its failure to prepare a risk assessment that is readily
understandable and integrates the five elements discussed earlier in Section III.
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24
ORP Question 2t Are the assumptions taade "by ORP in estimating radiation
risks reasonable, and are they justified in the supporting
; documentation?
There are a number of weaknesses in the ORP presentation. As noted in previous
sections of this report, the assumptions and methodology utilized by QRP in assessing
radiation risks are not presented- and integrated with sufficient clarity in the
supporting documentation. As a result, the Subcommittee was only able to clearly
comprehend the approach being used after it requested and received a large number
of briefings and supplemental written material. The public would experience great
difficulty in attempting to understand the ORP analysis based on the documentation
initially oade available.
In estimating cancer risks the ORP approach «BS weakened by the use of a
single dose-response model, the linear nonthreshold model* The use of only one
model, which is generally viewed as conservative, in the risk assessment phase is
scientifically inappropriate. A preferred approach would have' been to present a
range of models as discussed in BUR III report so that the risk manager could be more
fully informed as to the range of risk estimates that result froo the use of different
models*
An additional weakness is the variable degree to which attention is directed
to details of the dose and risk calculations. This is especially notable with regard
to age and time-dependent factors. ORP expended a greeted deal of effort, perhaps
an excessive amount in view of the strength of the underlying data and the extrapola-
tions, to use a life-table analysis approach to calculate how raany people (or statistical
fractions of individuals) die at specific ages- Yet, the calculations of dose per
unit intake of radioactivity apparently do not use an age-dependent factor* It was
not clear whether ORP did or did not use a special calculation to account for the
increased absorption of transuranics by newborns- It was also not clear if, following
radionuclide intake, the dose was assumed to be instanteously delivered or protracted
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25
In tine- For the thyroid, it is well known that the dose to the infant can be ten tines
higher than to the adult. Also, the fetus Is generally considered to be very
radiosensitive, but no calculation of in utero, dose is made. Thus, the great
detail of the lifeatable approach is not notched by the details of the dose calculations.
ORP Question 3: Is QRF's selection of the National Academy of Sciences/Bio-
logical Effects of tontaing Radiation lit report as the
e_
basic guide to radiation risk estimates scientifically
appropriate?
ORP appropriately selected the BEIR-III report as its basic guide to radiation
risk assessment. However, the contents of the report have been used in an excessively
selective manner. There appearsto havebeen little recognition given to the
caveats expressed by the BEIR-III panel or the limits In the applicability of the
report to standardjsetting. Basically, ORP has used the BEIR-III risk coefficients
presented for dose rates of 1 rad/yr (low LET radiatlon)to calculate the risks of
small increments of dose added to background which is approximately 0,1 rad/yr.
The conclusions reached by the BEIR-III panel were by no means unanimous and
Tuay be subject to change in the future. Many Subcommittee members believe that the
summed site approach, which was used by ORP for comparative purposes, gives values
for total cancer incidence that are much higher than the amount of human data
warrant.
Rsdiobiological data exist which indicate the likelihood that, at low doses and
low dose rates, biological effects may be less than that suggested by a linear
nonthreshold relationship! In this regard, the radioMological literature developed
from experimentation using raany different biological systems are a useful supplement
to the human data, and ORF should examine this information and make greater use of
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26
it. The Subcommittee also believes that the use of the BEIE III report, which for
cancer risks Is based largely on human data at high doses and brief exposures,
should be supplemented with other radiobiological data when extrapolations are made
to very low doses accumnulated over decades. This Subcommittee assertion is not
intended as a. criticism of the BEIR III panel's evaluation, for that report was not
designed as a risk assessment for standard setting at very low levels of exposure.
*.
ORF Question 4: Is the ORP analysis of potential lung cancer risks due to
radon progeny scientifically defensible?
EPA uses human epidetiiologlcal data linked to exposures quantitated in Working
Level Month (WLM) to assess the risk from radon daughters instead of using the
dosiaetrie approach used for other radionuelldes- Since the data are derived from
mining populations, it is modified somewhat so as to apply to the general population,
including children. Risk estimates are then compared with results analyzing other
population groups* ORP again selected a single value, three percent lung cancer
j •
Increase per WLM, as the relative risk coefficient. A range of values would have
been more appropriate since the value of three percent lung cancer increase per WLM
is open to challenge. Use of a range would not only address this criticism, but
would ultimately provide the regulatory decision maker with a clearer picture of
the uncertainties in this Important area. This is one risk value which must meet
real world criteria. The value should be consistent with predicting the incidence
of lung cancer in non-sraokers and their radiation exposures from naturally occurring
radon, and its daughter products and other ecological factors implicated in lung
cancer induction.
ORP Question 5: Is the wide range of uncertainty 'in estimates of human
cancer and genetic risk clearly presented?
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27
The Subcommittee Is concerned that ORP uses the conservative or worst case
linear extrapolation for earcinogenesis. I.e. extrapolation from acute high^dose
exposures, while simultaneously using the chronic low-dose exposure extrapolation
procedure for genetic effects. For genetic effects, the endpolnt of concern is the
nucleus. It Is taost likely that the nucleus is also the relevant target for important
aspects of induction of somatic effects since scientists now recognize the role of
oncogenes and chromosome re-arrangement in earclriogenesis. Thusj state-of-the art
understanding of the mechanism of cancer induction can no longer justify Ignoring
"dose-rate effects" in favor of linear high-dose extrapolation. Scientific panels
organized by the National Academy of Sciences, the United Nations Scientific Committee
on the Effects of Atomic Radiation (UNSCIAR), the National Council on Radiation
Protection (NCR?) and ICRP are In general agreement that some dose-rate effect
occurs, and each of these groups uses this assumption in calculating best estimates.
If ORP, in estimating somatic effects, continues to Ignore this approach in favor
1-1'
of its conservative analysis, It should explicitly state its reasons for proceeding
in this manner. At the same time, ORP should explain why it doesn't use similar
assumptions to calculate genetic health risks. In addition, in cases where ORP
proposes to use a years of life lost estimate per rad exposure for calculating the
risk of somatic effects, a parallel approach should "be applied to deriving a statement
of genetic risk (see UNSCEAR 82). Finally, BEIR III estimates for genetic effects
are low because the mouse female data are inappropriate for human extrapolation.
The immature mouse oocyte cannot be used to detect mutations since an lonizatlon
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28
traversal through the cell membrane kills the cell (Dobson, 1983)." faced with this
scientific uncertainty it would be Judicious for GRP to also give an alternative
estinjate, assuming equivalent mutability for both sexes, until there is other
evidence to the contrary.
ORP's selection of relative versus absolute risk models for estimating cancer
risks is another instance where a more detailed analysis and presentation would have
•Li
been useful. Both approaches have their strengths and weaknesses which should have
been elaborated. If one approach was to be selected over the others then it would
be appropriate to clearly document why it was selected and how it Is reflected in
the uncertainty of the final risk estimates.
In view of the above comments, the Subcommittee reeomnends that ORP contimr*
ally review the scientific literature and Modify its radiation risk estimates
periodically, as additional information becomes available. This recommendation is
especially appropriate at this time because exposure data from the Japanese A-Bonb
experience are presently undergoing revision and will presumably, it some point in
the near future, yield improved cancer risk estimates per rad of gamma radiation.
ORP Question 6; Is the ORP choice of the ICRP quality factor
of twenty for high LET radiation scientifically
reasonable or are there better alternatives?
The factor of twenty for high LET radiation appears appropriate when used by ICRP
and inappropriate when used by ORP. This is not a paradox as will be illustrated for
genetic risks. ICRP has a dose-rate factor for low LET radiation (chronic exposure)
which is what it compares to high LET radiation. In contrast, ORP uses a high
dose rate for low LET to compare with high LET, The factor of twenty is thus too
great. An ORP handout provided to the Subcommittee (reproduced on the next page)
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29
illustrates this point. The factor of twenty is clearly shown to apply only to low
dose rate LET (a factor of 6.7 applied to high dose low LET without a dose rate
factor)* Unless there is some other justification, which ORD should document, this
appears to be an example of compounding on error*
ORP Handout: "Serious Hereditary Disorders Per 106 Live borne/Per Rad of Parental
Exposure/Per Generation"
rg fqr_ First Generation Equilibrium
c,
Low Dose late
LOW-LET ]~~ 20 260
!
High Dose Rate 20x I
LOW-LET | 60 | 736
I _ I 6.7x
High-LET 1 400 I 5200
B. USE OF RISK ASSESSMENT IN RULEMAKING UNDER SECTION 112 OF THE CLEAN AIR ACT
EPA, in general, has been a leading practitioner of risk assessment in the
Federal government. At the same time, the use of risk assessment within EPA has a
if,.'
tftixed record both in terms of the consistency of approach utilized among the regula-
tory offices within the Agency and the varied scientific quality of individual risk
assessments. The former condition is, in part, the result of differing statutory
direction provided to EPA, although it Can also be attributed to the organization of
the Agency's major offices around a specific environmental media or problem area.
The different offices subject their risk assessments to varied degrees of peer
review and have scientific staffs with differing skills.
The process of preparing risk assessments to evaluate candidate pollutants
for regulation under Section 112 of the Clean Mr Act is, with the exception of
those prepared by ORP, managed by the Office of Health and Environmental Assessment
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30
(OHEA) which Is located within the Office of Hesearch and Development- Risk assess^-
merits prepared by OHEA which have led to the regulation of hazardous air pollutants
have consistently been reviewed by the Science Advisory Board* The process followed
by OHEA In developing a risk assessment for a specific pollutant includes the
following major sequential steps:
* compilation and interpretation of the scientific literature into a Health
Assessment Document. The document includes a discussion of differing
health endpoints (such as cancer, reproductive effects, and neurobehavloral
effects) and has a chapter on quantitative risk assessment. This chapter
presents the calculating procedures used in developing the risk assessment,
evaluates several mathematical models or relationships to test the "goodness
of fit" to the available scientific data, and compares the potency of the
pollutant under study to other pollutants.
* solicitation of public coument on the scientific adequacy of the Health
Assessment Document.
* Science Advisory Board review. To facilitate SAB review, OHEA staff prepare
an issues paper to identify key issues for SAB consideration and present
their own judgments about such key issues. The goal of this interaction
between the OHEA staff and the SAB is an advisory report transmitted to the
Administrator on the scientific adequacy of the Health Assessment Document-
The process used to achieve this goal is iterative and frequently leads to
the achievement of consensus regarding the interpretation of the scientific
daca for a particular pollutant.
There are several major advantages of the above described process. These include;
1) the separation of the risk assessment from risk management activities. The
scientific evaluation of a pollutant is completed, both Inhouse and externally,
prior to any Agency decision on whether to regulate or at what level to regulate;
2) the scientific community and the public at large are involved early In the
decision making process. Because scientists* participation in the review process
occurs before the Agency has committed itself to a specific regulatory course
of action, EPA is more able to respond to valid scientific criticisms by
modifying a document while it Is still in the risk assessment phase.
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31
3) the scientific basis for the risk assessment is made more explicit. Scientific
data ate compiled and evaluated In the Health Assessment Document, and key assump-
tions are identified in the document for public and SAB review. The result is
the development of an analytical bridge in the risk assessment that leads from
the scientific studies to the set of risk estimates generated by the mathematical
procedures employed*
The process followed by the Office of Radiation Programs In its developnent of
regulatory proposals to control airborne radionuclides is a najor exception to the
approach outlined above. The ORP did not compile and interpret the available
scientific evidence In a formal health risk assessment docuraent. Neither was there
ever a public or SAB review of the scientific basis upon which the Agency listed
radlonuclides as a hazardous air pollutant under Section 112 of the Clean Air Act-
C. SUBCOMMITTEE FINDINGS
1. The Subcommittee concludes that the Office of Radiation Programs' staff
has gathered the appropriate scientific data for Individual elements of a risk
assessment for radlonuclides emissions. Such Information was used by the Agency to
model the transport of airborne radionuclldes through environmental pathways and to
estimate the genetic and somatic health risks to humans iron calculated doses*
2. In its proposed standards to control airborne radlonuclides EPA stated that
its objective was to "restrict emissions from each site to the amount that would
cause an annual dose equivalent to 10 mllllrems (mrem) to the whole body and 30
area to any organ of any Individual. This emission standard will keep the radiation
doses relatively low both to nearby individuals and to populations living around
the sites." (pp.15077-78 Federal Register, April 6, 1983),
The Subcommittee nade numerous inquiries as to the scientific basis for the
specific levels chosen in the proposed emission standards. ORP staff, on March 22,
Identified five factors which they and senior policy officials weighed In decision
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32
making for the standard. These include: 1) the radiation dose and risk to nearby
individuals; 2) the cumulative dose and risk to population groups; 3) the potential
for emissions and risk to increase In the future; 4) the availability, practicability
and cost of control technology to reduce emissions; and 5) the effect of current
standards under the Act or other applicable legislative authorities.
The Subcommittee offers two observations about these decision criteria: 1)
it is not clear what relative weights were assigned to these factors In selecting
the levels for the proposed standards; and 2) most of the factors used to determine
the proposed level of the standards do not result per se from an evaluation of
scientific data in the preparation of a risk assessment.
Based upon the information it has received and reviewed, the Subcommittee concludes
that ORP did not prepare a risk assessment in support of this rulemaking activity that
integrated the available scientific data base. Of particular concern was the absence
of a statement characterizing the degree of uncertainty embodied within the risk
estimates for genetic or somatic effects. As discussed earlier, at several steps
In the estimation of risk there is the opportunity to consider alternative models*
It would have been useful to have the degree of uncertainty for the various alternatives
documented. A related concern Is the degree of selectivity In utilizing the existing
health effects literature (such as the BEIR III report) and the lack of balance iti
the discussion of other scientifically plausible assumptions covered In this literature.
In summary, the information ORP presented to the Subcommittee is not an adequate
or balanced assessment of the scientific data pertaining to airborne radlonudides, and
it cannot be judged as a__sclentlfically adequate basis for regulatory decisions for
this pollutant.
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33
3. The Agency requested that the Science Advisory Board review scientific
data associated with human health risk from radlonucltdes after It had formally
proposed a risk management decision In the Federal Register* The Administrator
has stated on numerous ocasslons that the major contribution of scientists to EPA's
decision making process lies in peer reviewing the technical basis of standards-
To achieve this result, scientists are Increasingly asked to present their opinions
before a risk management decision is proposed* By seeking SAB review of the
radlonucllde standards after their proposal, the Agency undermined the viability of
the concept of separating risk assessment and risk management that It is
seeking to Implement. The worst possible time to ask the SAB and the scientific
community to participate in the decision making process is following the
proposal of a standard when the risk assessment and risk management components
are blended together. As such, the approach used in this current rulemaklng
represents a major flaw in QRF's dialogue with the scientific community and
Its approach to risk assessment.
It has been noted that the SAB has the perogative of reviewing the scientific
basis of any of the Agency's proposed actions without waiting for a specific request
from the Agency. It is important that this avenue be kept open to the Board. However,
In the final analysis, it is the responsibility of the Agency to Identify those Issues
that are of highest priority for SAB review* Such a course is warranted recognizing
the limited size of the SAB and the myriad of issues it might potentially review*
4. Various offices within EPA are becoming increasingly sophisticated In
their approach to characterizing and assessing human health risks. These efforts
logically lead the Agency to present comparisons of risk estimates for different
pollutants and to use risk assessment as a tool to define public health priorities
to achieve more cost-effective environmental protection. It Is not clear that the
Office of Radiation Programs, in its approach to risk assessment, is greatly Influenced
by this trend. As such, ORP may not be taking sufficient advantage of these evolving
-------
conceptual advances* At the same tine, QRP, with tts long experience in exposure
assessment, day not be articulating to the Agency the benefits of its knowledge in
this field* In short, the Subcommittee is concerned that QRP is not in the mainstream
of EPA's .continuing efforts to improve the practice of risk assessment.
IV, SUBCOMMITTEE CONCLUSIONS AND RECOMENDATIOHS
A. NEED FOR A SCIENTIFIC ISSUES STAFF PAPER TO IDENTIFY AND EVALUATE
THE SCIENTIFIC BASIS FOR RADIATION RISK MANAGEMENT DECISIONS
The Subcommittee's major finding in Its review of the scientific data
associated with EPA's radionuclides rulemaking efforts is that the DIP has not
assembled and presented a risk assessment that provides a clear and adequate statement
of the scientific basis for developing standards to regulate airborne radionuclide
emissions. What is needed is an intermediate step between the collection of the
relevant scientific information, which ORP has carried out in a proficient manner
In the current ruleaaking, and the selection of regulatory options for purposes of
risk management*
Such an Intermediate step has already been developed in other progran offices
within EPA and Is regarded as successful by both Agency staff and the general
public, including the scientific community* For example, the Office of Air Quality
Planning and Standards (OAQPS) has since 1979 prepared a scientific Issues staff
paper that provides an analytical bridge between a large nuetber of scientific
studies included in the air quality criteria document and the staff interpretation
of how to use such studies as a basis for defining regulatory options* These staff
papers are routinely reviewed by the public and the Science Advisory Board, and
they have enhanced EPA*s credibility in the setting of ambient air quality standards.
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35
The Subcommittee strongly recommends that the preparation of a scientific
issues staff paper incorporating an integrated risk assessment become a routine
part of the ORP*s regulation development process. The scope and complexity of an
individual staff paper may vary in accordance with the rule under development, but
certain generic characteristics of the staff paper concept are self evident. In
the case of airborne radionuelides, for example, the staff paper should provide a
conceptual franework that includes the state of knowledge to assess radiation risks
beginning with 1) identification of radionuclides emissions sources; 2) evaluation
of the transport of radionuelides through all relevant environmental nedlaj 3)
calculation of the dose received by a human population; 4) estimation of genetic or
sowatic health effects and (5) identification and characterisation of the degree of
uncertainty in the risk estimates. The latter should include a presentation of
central estimates with lower and upper bounds for cancer and genetic endpoints* Such
endpoints should then be compared to existing data on the incidence EPA attributes to
various envlronaental, occupational and social factors. It might also be appropriate
f !
for this position paper, or a complementary document, to identify for various potential
levels of a standard if compliance could be established by direct measurements or only
Indirectly by modeling. In summary, a staff paper can synthesize the scientific
data base which the risk manager must utilise to propose reasonable and scientifically
defensible standards.
B. ESTABLISHMENT OF CONTINUING SCIENTIFIC OVERSIGHT MECHANISM TO REVIEW
ASSESSMENTS FOR RADIATION STANDARDS AND OTHER ORP ACTIVITIES
The Subcommittee recommends the establishment of a continuing mechanism to
provide scientific oversight and peer review of the scientific basis of ORP's regu-
latory proposals and Its scientific activities. Such a mechanism could take the
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36
fona of a permanent standing committee within the IPA's Science Advisory Board.
The Board is well suited to carry out this role for several reasons. These include
1) Its statutory basis provides for "both a continuous advisory relationship with
the Agency and a clear delineation of Its peer review role and authority; 2) It is
able to" attract highly qualified, independent and respected scientists and engineers
to serve on Its advisory panels; 3) a number of highly qualified scientists with
expertise in radiation risk assessment currently serve on the Board; and 4) the
establishment of a standing radiation committee within the Board Is administratively
simple and feasible from a budgetary point of view. A proposed charge for such a
committee Is given In Appendix 6*
C. INTEGRATION OF RISK ASSESSMENT EFFORTS BETWEEN THE OFFICE OF RADIATION
PROGRAMS AND OTHER STAFF OFFICES WITHIN EPA
ORP efforts in risk assessment are not sufficiently Integrated with other
staff offices that are working to refine the Agency's approach to risk assessment.
This Is a two-way street in that ORP could benefit by Implementlog some of the
increasingly sophisticated efforts used in other parts of EPA to characterize and
compare risks, while simultaneously the ORP staff could further educate their
colleagues In areas, such as exposure assessment, where It possesses much expertise
and experience* To achieve this result the Subcommittee recommends that ORP and
the Office of Health and Environmental Assessment take more formal steps to Integrate
their preparation of risk assessments* A specific recommendation is that OHEA be
represented on ORP work groups that prepare risk assessments for setting radiation
standards* In addition, the ORP risk assessment effort is related to scientific
modeling studies under way In the Office of Air Quality Planning and Standards, as
well as related work In various other government and private agencies* The Subcommittee
encourages ORP to continue to seek ways to improve its Interaction with all such
groups.
-------
37
D. RESEARCH NEEDS
The Subcommittee believes that the identification, of areas requiring additional
research will provide useful input Co those directing research programs in EPA and
other Federal Agencies. The Subcommittee sees the need for additional research in
the following areas:
1, The development air transport radioactivity models for situations
other than emissions from tall stacks nay become a topic of increasing
importance for standard setting in future years.
2. The continuing assessment of the Japanese A-bonb data for improvement
of the BEIR-III estimates of radiation hazard is needed to further refine
estimates of health risks frora current nan-made sources of radlonuclides.
3. The determination of the nature of dose-response relationships at low
dose rates, as e.g. non-linearity in the linear-quadratic or quadratic
relationships, could affect profoundly the estlaates of radiation
..'
hazards at levels of great concern to the EPA*
4. There is a great need to validate radiation doses estimated with
models and subsequent computer codes by means of measurement of
radioactivity levels in air, on .the ground and in plants, animals and
humans in proximity to the radiation source(s).
5. The ultimate development of dynamic models having applicability to
specific geographic regions is technically possible. Such models should
provide the greater accuracy and credibility of assessments that is
desired.
6. The development of more sensitive methods to determine genetic damage
is an important research need. The advancing state-of-the-art is
making It possible to plan DNA studies of children, for example.
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APPENDIX A
U.S. Environmental Protection Agency
Subcommittee on Risk Assessment for Radionuelides
Science Advisory Board
Chairman.
Dr. loger 0. McClellan
Director of Inhalation Toxicology
Research Institute
Lovelace Blomedlcal and Environmental
Research Institute *.
P.O. Box 5890
Albuquerque, New Mexico 87115
ExecutiveSecretary
Dr. Terry F. Yosie
Staff Director
Environmental Protection Agency
Science Advisory Board (A-lOl)
401 M Street, S.W.
Washington, B.C. 20460
Panel Roster
Dr. Seymour Abrshamson
Professor of Zoology and Genetics
Department of Zoology
University of Wisconsin
?ladison» Wisconsin 53706
Dr. Lynn Anspaugh
Lawrence Ltvermore National
Laboratory
P.O. Box 5507; L-453
Live more, California 94550
Dr* Victor Archer
Rocky Mountain Center for
Occupational Health
Building 512
Salt Lake City, Utah 84112
Dr. Victor P. Botid
Associate Director
Brookhaven National Laboratory
Upton, New York 11973
Dr. Gordon L. Brownell
Physics Research Laboratory
Massachusetts General Hospital
Boston, Massachusetts 02114
Dr. Merrill Eisenbud
New York University
Lanza Laboratory
Long Meadow load
Tuxedo, New York 10987
Dr. Frank A. Gifford
109 Gorgas Lane
Oak Ridge> Tennessee
37830
Dr. James V* Neel
Professor of Hunan Genetics
University of Michigan Medical
School
Department of Hunan Genetlcs~Box 015
1137 E Catherine Street
Ann Arbor, Michigan 48109
-------
Dr. WllUam J. Schull
Director and Professor of
Population Genetics
Center for Demographic and
Population Genetics
School of Public Health
University of Texas Health
Science Center at Houston
Houston, Texas 77030
Dr. Donovan Thonpson
4231 NE 73ra
Seattle, Washington
98115
Dr. F. Ward Whicker
Department of Radiology and Radiation Biology
Colorado State University
Ft. Collins, Colorado 80523
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APPENDIX B
1 UNITED STATES ENVIRONMENTAL PROTECTION AGENCY
^4" WASHINGTON. D.C. 204iJ)
DEC 6 1983
THE ADMINISTRATOR
MEMORANDUM
«_
SUBJECT: SAB Review of Risk Estimates Due to Radionuciides
TO: Chairman, Science Advisory Board
The Environmental Protection Agency's (EPA) responsibilities for
protecting the public from exposure to radioactive materials requires that
we conduct several regulatory programs. To make clear that these programs
are based on analysis of the scientific information that is reasonable and
rigorous, I request that the Science Advisory Board convene-a special
subcommittee to review the scientific, basis of the risk assessments used
to develop standards for protection fram radionuclidea in the environment.
This is an urgent task because of the Agency's statutory deadlines
for completing ongoing regulatory programs, and the need to resolve public
comments and other concerns expeditiously. I request that the subcommittee
make every effort to complete its review and report it§ findings within
three months. " " "~*
1 am requesting that the subcommittee critically review the process
by which the Agency estiosa.tes human caneSr and genetic risk due to
radionuclides in the environment. This review should include 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. The subcommittee should reader an
opinion on whether EPA is using basic references on dosimetry models or
risk estimates prepared by other expert committees such as the National
Academy of Sciences' (HAS) Committee on the Biological Effects of Ionizing
Radiation (BEIR), and the International Commission on Radiological
Protection (ICR?) in a scientifically acceptable manner.
I believe it is particularly important that the subcommittee
concentrate on whether the Agency has proceeded in a reasonable and
scientifically sound way. In this vein, please look at procedures,
information bases, and the reasonableness of the approach, I am seeking a
review of the overall scientific bases used by the Agency is making
radiation risk estimates.
-------
the methodology that you will be reviewing is used to assess risks
associated with source categories and specific facilities as part of the
development of EPA's proposed standards. It would be helpful to me if the
subcommittee concentrated on A few sample cases to ensure that the
Agency's staff properly applied the general methodology,
I believe thst risk assessment and risk management are distinct
aspects of regulation development. Methodologies for risk assessment must
be based on sound scientific information and principles, whereas risk
management decisions need to take the results of the risk assessment and
balance then with legal, economic, and other relevant factors. I believe
the latter are policy decisions that are the responsibility of EPA staff
and its senior managers after receiving appropriate comment through the
rulemaking process. Examples of what I conceive as risk management issues
are what constitutes an "ample margin of safety" and what constitutes
acceptable risk levels*
Mr. Glen L. Sjoblom» Director of the Office of ladiation Programs and
his staff stand ready to provide the subcommittee with appropriate
briefings, background information, and necessary support so that your
review can proceed as expeditiously 'as "possible, I have attached a list
of specific questions prepared by the Office of Radiation Programs for the
subcommittee's review.
I am looking forward to the results of the review and' plan to
carefully consider it when making my decisions on the major risk
management issues that involve exposure to radiation.
William D. Ruckelshaus
Attachment
-------
Office of Radiation Programs; Questions for the SAB
I, Has cue Office of Radiation Programs (QHP) considered and
interpreted in a scientifically adequate manner the appropriate literature
on radiation risk assessment including data sources on radiation risks?
Please identify any important omissions.
2. Axe the assumptions made by OEP in estimating radiation risks
reasonable, and are they justified in the supporting documentation?
3. . Is QRP's selection of the NASHBEIR III report as the basic guide
to radiation risk estimated scientifically appropriate?
4i Is tne OR? analysis of potential lung cancer risks due to radon'
progeny scientifically defensible?
< .,*..* ' j*. j-
5. Is the wide range of uncertainty in estimates of human cancer and
genetic risk clearly presented?
6. Is the OSP choice of the ICRP quality factor of twenty for high
LET radiation scientifically reasonable or are there better alternatives?
7. Is the choice of ICRP dosimetic models scientifically adequate?
Are there any alternatives? "'*
8. In a fet* cases EPA has used organ transfer factors for a general
population ratner than Jt&ose fo'r "occupational workers* Are 'these changes
appropriate and justified in the documentation?
9. Are the air dispersion models reasonable to estimate radionuclida
concentrations (1) in the neighborhood of a source? (2) to regional
populations?
10. la tae selection of transfer factors and other parameters in the
food chain analysis reasonable?
-------
APPENDIX C
Wednesday
April 6, 1983
Part II
Environmental
Protection Agency
National Emission Standards for
Hazardous Air Pollutants; Standards for
Radionudides
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15076
Federal Register / Vol. 48, No. 87 / Wednesday, April 6,1803 / Proposed Rules
ENVIRONMENTAL PROTECTION
AGENCY
40 CFH Part 81
[AH-FBt, 2324-33
National Emission Standards for
Hazardous Air Pollutants; Standards
for Radionuclidea
AGENCY: Environmental Protection
Agency {EPA),
ACTION: Proposed Rule and
Announcement of Public Hearing,
5UMMABY: On November S, 1979, EPA
listed radionuclides as a hazardous air
pollutant under the provisions of Section
112 of the Clean Air Act, Pursuant to
Section 112, EPA is proposing standards
(including appropriate reporting
requirements) for sources of emissions
of radianuclides in four categories; (!)
Department of Energy (DOE) Facilities,
(2) Nuclear Regulatory Commission
licensed facilities and non-DDE Federal
facilities, (3} underground uranium
mines, and (4} elemental phosphorous
plants.
The Environmental Protection Agency
{EPA) has identified several additional
source categories that emit
radiomiciides and has determined there
are good reasons for not proposing
standards at this time for these
categories. They are the following; (1)
coal-fired boilers. (2) the phosphate
industry, (3) other extraction industries,
(4) uranium fuel cycle facilities, uranium
mil! tailings, management of high level
waste, and (5) low energy accelerators.
BATES: Comments may be received on
or before May 30,1983,
Public Hearings. Aft informal public
hearing will be held on April 26.39, and
30,1983 in Washington, D.C. The exact
time and location of the hearing can be
obtained by calling the Office of
Radiation Programs at (703) 557-0704
Requests to participate in the informal
hearing should be made by April 20,
1983. Written statements may be
entered into the record before, during, or
within 30 days after the hearing.
ADDRESSES: All written comments
should be submitted to tht> Central
Docket Section (A-130), U.S.
Environmental Protection Agency,
Washington. D.C. 20460, Attention:
Docket No. A-79-11. This docket,
containing information used by EPA in
developing the proposed standards, is
available for public inspection between
8:00 a.m. and 4:00 p.m., Monday through
Friday al EPA's Central Docket Section,
West Tower Lobby. Gallery One.
Waterside Mall. 401M Street SW.,
Washington, D.C. 20460,
Separate sections of the docket have
been established for each category of
radionuclide emissions to air. Comments
specific to a proposed action should be
addressed to the following docket
sections:
Section III A—Department of Energy
Facilities
Section III 0—NweJf ar Regulatory
Commission Licensed Facilities and non-
DOE Federal Facilities
Section 111 C—Underground Uranium Mines
Section III D—Elemental Phosphorous Plants ,
Section III B—Coal-fired Boilers
Section III F—Phosphate Industry
Section HI G—Other Extraction IndustrieB
Section MI H—U«nium Fuel Cycle Facilites,
Uranium Mill Tailings, and Management of
High Level Waste
Section III I—Law Energy Accelerators
Requests to participate in the informal
hearing should be made in writing to
Richard J, Guimond. Director, Criteria
and Standards Division (ANR-460), U.S.
Environmental Protection Agency,
Washington, D.C, 20460, All requests for
participation should include, at least, an
outline of the topics to be addressed in
the opening statements and the names
of the participants. Presentations should
be limited to 15 minutes each,
A Background Information Document
has been prepared that contains, for
each source category, projected doses
and risks to nearby individuals and to
populations, descriptions ofkurrtnt
control technology, and descriptions and
costs of emission control technologies.
Single copies of the Background
Information Document for the proposed
standards may be requested in writing
from the Program Management Office
(ANR-458). U.S. Environmental
Protection Agency, Washington, D.C.
10460, or by calling (703) 557-9351.
FOR FURTHER INFORMATION CONTACT:
Terrence A, McLaughlin, Chief,
Environmental Standards Branch (ANR-
460), U.S. Environmental Protection
Agency, Washington, D.C. 20460, [70S)
557-8977.
SUPPLEMENTARY INFORMATION:
{. Overview of the Proposed Standards
A, Basic Terms Used in This Notice
All matter is made up of atoms: their
nuclei contain protons and neutrons..
The number of protons in an atom
determines the identity of the element.
For example, the element with. 6 protons
is nailed carbon. Atoms can contain
different numbers of neutrons. The total
number of protons and neutrons in an
atom is called the atomic weight,
The nuclei of atoms of chemical
elements with curtain atomic weights
are unstable by nature. Such nuclei can
disintegrate spontaneously in
predictable wnys and are said to be
radioactive. Atoms with nuclei that
disintegrate are called radionoclides.
For example, carbon atoms with 8
neutrons disintegrate, whereas carbon
atoms with 6 neutrons are stable. The
number of disintegrations which will
occur in a given amount of time is
termed activity: the umt o£ activity is the
curie. One curie equals 37,000,000.000
disintegrations per second.
Some radlonuclides are found in
nature; others are made in reactors and
accelerators. This notice concerns
facilities which handle or produce all
types of naturally occurring and
manmade radioAudides in a manner
that results in their being released into
the air.
B, Bockgroend
In 1977. Congress amended the Clean
Air Act (the Act} to address airborne
emissions of radioactive materials.
Before 1977, these emissions had been
either regulated under the Atomic
Energy Act or unregulated. Section 122
of the Act required the Administrator of
EPA, after providing public notice and
opportunity for public hearings
(provided by 44 FR 21704, April 11.
1979), to determine whether emissions of
radioactive pollutants cause or
contribute to air pollution thai may
reasonably be anticipated to endanger
public health. On December 27.1979.
EPA published a Federal Register Notice
listing radionuclides as hazardous air
pollutants under Section 112 of the Act
(44 FR 76738, December 27,1979), To
support this determination, EPA
published the report titled RadiohgSeal
Impact Caused By Emissions of
RtidianuclJdes into Air in the United
States—Preliminary Report (EPA S20/7-
79-006). Office of Radiation Programs.
U.S. Environmental Protection Agency,
Washington, D.C (August 1979).
Section 122(c)(2) of the Act directed
that, once EPA listed radionuclides to be
regulated under Ihe Act, EPA and the
Nuclear Regulatory Commission (XRC)
were to enter into an interagency
agreement with respect to those
facilities under MRC jurisdiction. Such a
memorandum of understanding was
effected on October 24,19SQ, and was
subsequently published in the Federal
Register (45 FR 72980. November 3,
1980). When EPA began developing
Standards for Department of Energy
(DOEJ facilities, a similar memorandum
of understanding was negotiated with
DOE This memorandum of
understanding was signed in October
1982. and a copy has been placed in tbe
Docket for public review.
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Federal Register / Vol. 48. No. 67 / Wednesday. April 6. 1983 / Proposed Rules 15077
On June 16,1981, the Sierra Club filed
suit in the U.S. district Court for tht
Northern District of California pursuant
to the citizens* suit provision of the Act
(Sierra Club ¥. Coreueh, No. 81-2436
WTS), The suit alleged that EPA had a
nondiscretionary duty to propose
standards for radionuclides under
Section 112 of the Act within 180 days
after listing them. In March 1982, the ''
Court granted the Sierra Club motion for
partial summary judgment on the
liability issue, and, on September 30,
1982, the Court ordered EPA to publish
proposed regulations establishing f
emission standards for rsdionuclides,
with a notice of hearing, within ISO days
of the date of that order.
EPA is proposing standards for certain
sources of radionuelidi emissions to air
and is proposing not to regulate other
sources. To EPA's knowledge, these
comprise all source categories that
release potentially regulatabie amounts
of radionuelides to air. The deadline
established by the Court for this
rulmaking has required EPA to proceed
with less information than It would like,
As always, EPA invites comments and .
will consider them carefully to ensure
that the Agency's decisions are the best
possible ones,
C, Estimates of Health Risk
Agencies can never obtain perfect
data but have to make regulatory
decisions on the basis of the best
information available. Although
additional study may be suggested to
clarify the health implications from
exposure to radiation at relatively low
levels, EPA is concerned about the
potential detrimental effects to human
health caused by radiation based on the
best scientific information currently
available. EPA believes its estimates of
doses to humans and the potential
human health risks constitute an
adequate basis for decisionmaking.
The information used by the Agency
in estimating the hazards to health due
to exposure to radiation is summarized
in the following reports; The Effects on
Populations of Exposure to Low Levels
of Ionizing flttdiatian (1972) and Health
Effects of Alpha Emitting Particles in
the Respiratory Tract (1970) by the BEIR
Committee, the report of the United
Nations Scientific Committee on the
Effects of Atomic Radiation entitled
Sources and Effects of Ionizing
Radiation (1977), and Publication £6
[1977) by the International Commission
on Radiological Protection. These bodies
agree that high levels of radiation cause
cancer and mutations and that, when
formulating radiation protection
standards and guidance, it is reasonable
to assume that the risks of cancer and
mutations are proportional to radiation
dose. Background information on the
risk associated with radon emissions
can be found in an EPA report titled
Indoor Radiation Exposure Dae to
Rodium-228 m Florida Phosphate
Lands, [EPA 520/4-78-013] (1978).
In concert with the recommendations
of thtSe reports, even for relatively low
doses, EPA has assumed a linear,
nonthreshold, dose-effect relationship as
a reasonable basis for estimating the
public health hazards due to exposure to
radiation. This means that any radiation
dose is assumed to pose some risk of
damage to health and that the risk
associated with low doses is directly
proportional to the risk that has been
demonstrated at higher doses. EPA
believes this assumption is reasonable
for public health protection in light of
presently available information.
However, EPA recognizes that the data
available preclude neither a threshold
for some types of damage below which
there are no harmful effects nor the
possibility that low doses of gamma
radiation may be less harmful to people
than the linear model implies.
As used in this notice, the term "dose
to an individual" means an estimate of
the dose rate in units of dose equivalent
per year {rern/y} to the whole body or to
a specified body organ due to exposure
to radiation at a given level for the
person's lifetime (70 years). These dose
rates ire a measure of, although not
directly proportional to, the individual's
risk of fatal cancer. The term "lifetime
risk to an individual" means an estimate
of the potential probability of premature
death due to cancer caused by radiation
exposure at a given level for the
person's lifetime- There are also risks of
nonfatal cancer and serious genetic
effects, depending on which organs
receive the exposure.to radiation. The
risks of nonfatal cancer and genetic
effects cannot be accurately estimated.
but neither risk is larger than the fatal
cancer risk. EPA considers all these
risks when it makes regulatory decisions
on limiting emissions by restricting dose
rates or exposures to radionuclide
concentrations.
As used in this notice, the term "dose
to population" means an estimate of the
summed dose received by all persons in
a population living within a given
distance of the source, typically within
80 kilometers, due to a One year release
of radionuelidea (person-ram per year of
Operations), A person-rem is a total
amount of exposure received by a large
group equivalent to one person receiving
an exposure of One rem. The term "risk
to population" means an estimate of the
number of potential fatal cancers that
might occur in the population living
within a given distance of the emission
source, typically within 80 kilometers.
The risk is related to the amount of
radionuclides that are emitted during a
year of operation. Part of the population
risk is likely to occur some time after the
radionuclides are emitted because; Jl)
There is a delay between release and
exposure as the radionuclides move
through environmental pathways and (2J
there 5s a latent period between
exposure and the onset of the disease.
The dose to populations for a specific
Organ is related to, although not directly
proportional to, the risks of fatal cancer,
nonfatal cancer, and serious genetic
effects. EPA considers all fatal and
nonfatal risks In making regulatory
decisions on whether standards are
needed to protect the general public- As
Used in this notice, the term "health
effeet"*means potential fatal cancers.
Additional information on risk can be
found in the Draft Background
Information Document.
EPA must make numerous
assumptions when estimating the
radiation dose to individuals and
population groups and the likely risk
this might present to health. The
assumptions introduce uncertainties in
the estimates of radiation, doses and
health risks. All individual risk
calculations assume that individuals
reside' at a single location for a 70 year
life and are exposed to a constant
source of radSonuclide emissions for the
entire time, factors such as radionuclide
uptake by vegetation, consumption of
locally produced Crops and milk, and
meteorology are quite site specific and
can influence the actual risk to any
given individual. Individual
characteristics such as age. physiology.
physical activity level, amount of time
spent indoors, and eating habits can
influence the rate and amount of
radionuclides affecting the individual
and, thus, the risk of that person.
EPA's risk estimates are "best
estimates" considering the above .
factors, EPA believes that the estimates
are within a factor of ten of the actual
health risks to individuals if the
assumptions are vsiid for the particular
situation under.consideration.
D, Summary °f &Q Proposed Standards
EPA is proposing specific standards
for sources in four categories; (1) DOE
facilities, (2] NRC-licensed facilities and.
non-DDE Federal facilities, [3J
underground uraniaffl mines and (4)
elemental phosphorous plants.
An indirect emission standard is
proposed for all DOE facilities that will
restrict emissions from each site to the
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15078
Federal Register / Vol. 48, No. §7 / Wednesday, April 6, 1983 / Proposed Rules
amount that would cause an annual
dose equivalent to ID inillirem (tnremj to
the whole body and 30 mrem to any
organ of any individual. This emission
standard will keep the radiation doses
relatively low both to nearby
individuals and to populations living
around the sites. In addition. EPA
expects these facilities to continue to
comply with the current Federal
Guidance requirement that emissions be
limited to as low as practicable levels
and has proposed a reporting
requirement to describe emission
control technology.
An indirect emission standard is
proposed for NRC licensees and non-
DOE Federal facilities that will restrict
emissions from each site to the amount
that would cause an annual dose
equivalent of 10 mrem to any organ of
any individual. This emission standard
will keep radiation, doses relatively low
to nearby individuals and populations in
the vicinity of the site. The term "NRC
licensees" includes those facilities
licensed by the NRC and by States
under agreement with the NRC,
An indirect emission standard is
proposed for underground uranium
mines that will restrict the Increase in
annual average concentration of radon-
222 at places people can live to 0.2
pieecurie per liter (pCt/1). A person
living in a house for a long time is an
area exposed to this concentration might
still be subject to a significant estimated
level of risk, However, neither control
technology nor other methods to reduce
radon emissions from these mines are
available at reasonable cost; thus, more
restrictive controls are not reasonable.
The proposed standard will reduce risk
to people living closest to the mines;
protection of the health of regional and
more distant populations is of less
concern because most mines are located
in remote areas.
An emission standard is proposed for •
elemental phosphorous plants that will
limit annual emissions of polonium-210
from each site to 1 curie. While other
radionuulidcs are emitted from these
plants, poloniun>210 is the major
contributor to the maximum individual
risk. Limiting polonium-210 will control
the others. Such a standard will keep
radiation doses relatively low to both
individuals and populations,
While one of the above standards
limits stack emissions directly, the other
three limit stack emissions indirectly by
specifying dose or concentration limits
to be achieved, EPA believes this is a
reasonable approach, given the extreme
diversity of DOE facilities and NRC
licensees and the fact that randon-222
emissions from uranium mines are not
amenable to controls. The form of the
proposed standards follows well
developed and widely accepted
practices in radiation protection. The
use of procedures developed primarily
to control chemicals would, in this
context, be unworkable,
£ Basis for the PfOposed Standards
In the Federal Register of May IS,
I960, President Eisenhower directed
Federal agencies to follow the Radiation
Protection Guidance of the Federal
Radiation Council (FRC). When IPA
was established, the Federal Radiation
Council was abolished, and its
responsibilities were transferred to EPA.
EPA has considered this Guidance in
establishing emission standards under
Section Ji2 of the Clean Air Act, and the
Agency's approach is compatible with it.
For the purposes of this rulemaktag, key
elements of the Guidance are;
1, There should not be any man-made
radiation exposure without the
expectation of benefit resulting from
such exposure.
2. Ths term "Radiation Protection
Guide" should be adopted for Fedtral
use. This term is defined as the radiation
dose which should not be exceeded
without careful consideration of the
reasons for doing so; every effort should
be made to encourage the maintenance
of radiation doses as far below this
guide as practicable,
3, For the individual in the population,
the basic Radiation Protection Guide for
annual whole body dose in 0,5 rem. This
Guide applies when the individual
whole body doses are known. As an
operational technique, where the
individual whole body doses are not
known, a suitable sample of the exposed
population should be developed-whose
Protection Guide for annual whole body
dose will be 0,17 rem per capita per
year.
4. There can be no single permissible
or acceptable level of exposure without
regard to the reason for permitting the
exposure. It should be general practice
to reduce exposure to radiation, and
positive efforts should be carried out to
fuifitt the sanse of these
recommendations. It is basic that
exposure to radiation should result from
a real determination of its necessity.
5. There can be different Radiation
Protection Guides with different
numerical values, depending upon the
circumstances.
0, The Federal agencies shall apply
these Radiation Protection Guides with
judgment and discretion to assure thai
reasonable probability is achieved in
the attainment of the desired goal of
protecting man from the undesirable
effects of radiation. The Radiation
Protection Guides provide a general
framework for the radiation protection
requirements. It is expected that each
Federal agency, by virtue of its
immediate knowledge of its operating
problems, will use these Guides as a
basis upon which, to develop detailed
standards tailored to meet its particular
requirements.
EPA believes that the following points
in those guides are of particular
importance; {1} There should be benefits
frtfm exposure to radiation; (2J
Exposures should be kept as low as
practicable: and (3) It is appropriate to
have different standards with different
values, depending on the circumstances.
These Guides apply to Federal
agencies to the extent that they are not
iittconipatible with mere speciiic
legislative directives. The Clean Air Act
directs EPA to establish emission
standards for hazardous pollutants and
directs EPA to propose these standards
at m level which, in the Administrator's
judgment, will protect the public health
with an ampJe margin of safety.
Congress did not describe the degree of
protection that provides an ample
margin of safety, nor did it describe
what factors the Administrator should
consider in making these Judgments.
Therefore, EPA considers those factors
it believes are necessary to make
reasonable judgments on whether
standards are needed and, if so, at what
level theyshould be established.
If a hazardous pollutant under review
has been shown to possess a. threshold
level below which no deterimental
health effects are likely, it might be
relatively easy to establish an emission
standard. For example, the Agency
might select an appropriate safety
factor, divide the threshold level by thi?
factor, and establish an emission
standard that corresponds to the
reduced level This regulatory strategy
would provide reasonable assurance
that no detrimental effects would result
from exposure to the hazardous
pollutant
This approach is not feasible or
reasonable for radionuclides. This is
because the risk of cancer from
exposure to radiation has not bepn
shown to have a threshold level.
Consequently, if EPA applied the
approach previously described, the
Agency would likely conclude that the
standard should be established at zero *
emissions. They only way to mee! such
a standard would be to close all
facilities emitting radionuclides because
it 13 impossible to reduce radionuclide
emissions to zero through control
technology. If this approach were
adopted society would be harmed
since it would have to forgo the
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15079
benefits of industries that emit
radionuelides. Therefore, to allow
society to continue to benefit from these
activities, EPA must establish emission
standards for radionuclides at a level
thai rnay present some human health
risk. The Agency is not aware of any
single level of riik that would be
generally acceptable or constitute an
ample margin of health protection. Some
argue that an increase in cancer risk not
exceeding one in 1,000 due to a specific
cause is acceptable, whereas others
argue that an increase in risk of one in
one million is unacceptable. EPA <-
believes it should adopt an approach
that will allow those various factors that
influence society's health and well being
to be weighed in assessing each source
category. To accomplish this, EPA has
decided to consider the following factors
in making its judgments:
1, The radiation dose and risk to
nearby individuals;
2. The cumulative radiation dose and
risk to populations in the vicinity of the
source;
3. The potential for radiation
emissions and risk to increase in the
future;
4. The availability, practicality, and
cost of control technology to reduce
emissions; and
5- The effect of current standards
under the Act or other applicable
legislative authorities.
By considering these factors, EPA will
be able to provide public health
protection that is consistent with the
intent of the Federal Radiation
Protection Guides and Clean Air Act.
The first three factors are used to
assess the likely impact of emissions on
the health of individuals and large
populations and to estimate the
potential for significant emissions in the
future. The fourth factor enables EPA to
assess whether state-of-the-art control
technologies are currently in use and
whether there are any practical means
of reducing emissions through control
technology or other control strategies.
The last factor allows EPA to assess
whether regulations or standards thai
have been established to control
particulates or other pollutants are also
minimizing releases of radionuciides.
The dose and risk to (he individuals
nearest a site are often the primary
considurations when evaluating the
need to control emissions of
radionuclides. Controlling maximum
individual dose assures that people
living nearest a source are not Subjected
to unreasonably high risk. Further,
protcwiing individuals usually provides
an adequate level of protection to
populations living further away from the
source. Estimating the maximum
individual dose and risk allows a
comparison of the potential impact of
one source to other sources,
EPA believes that cumulative
population dose and risk also need to be
examined. The cumulative radiation
dose and risk to surrounding
populations are determined by adding
together all of the individual doses and
risks that everyone within a certain
radius (usually 80 km) of an emission
source receives. This factor can
sometimes be more important than the
maximum individual risk in deciding
whether controls are needed,
particularly if an txtremeiy large
population may be exposed. The
aggregate dose and population risk can
be of such magnitude that it would be
reasonable to require i reduction in the
total risk even though, if the maximum
individual dose were considered alone,
one might conclude that no further
controls are needed.
In addition. EPA believes that the
potential for emissions and risk to
increase in the future needs to be
considered even though the current
projected maximum individual and
population risks are very low. An
emission standard might be appropriate
because the Facilities now, or may in the
future, handle large quantities of
radionuclides that could escape into the
air if improperly controlled.
Alternatively, when the amount handled
by a facility is small or is decreasing,
and there is no potential for large
releases now or in the future, standards
may not be needed,
The availability and practicality of
control technology are important in
judging how much control of emissions
is warranted. For this rulemaking, EPA
believes that the standard should be
established at a level that will require
best available technology with
allowance for variation in emissions,
once a determination is made that
additional controls are necessary.
Additional actions, such as requiring
development of new technology, closure
of a facility, or other extreme measures
may be considered if significant
emissions remain after best available
technology is in place or if there are
significant emissions and there is no
applicable control technology, EPA is
defining best available technology as
that which, in the judgment of the
Administrator, is the most advanced »
level of controls adequately
demonstrated, considering economic,
energy, and environmental impacts, The
technological and economic impacts
associated with retrofits are considered
when determining best available
technology for existing Sources.
Finally, EPA believes it is reasonable
to consider whether other EPA
standards are achieving approximately
the same goal as the Act, i.e., protecting
public health with an ample margin of .
safety. In cases where other standards •
are providing comparable control for
radionuciides, EPA believes it is
appropriate not to propose redundant
standards under the Act. There would
be no benefits because the public health
would already be protected with an
ample margin of safety, but there could
be unnecessary costs associated with
implementing an additional standard.
EPA considered each of the relevant
factors in making determinations for
each source category that was reviewed.
These factors were not quantitatively
balanced through tie use of formulas to
derive etnissioa limits. Rather, they were
qualitatively weighed before deciding
whether a standard was needed and, if
so, what level of control was suitable.
The consideration of these factors as
they apply to each source category is
detailed in the portion of this preamble
devoted to that source category,
EPA requests comments on the
appropriateness of the factors it has
selected for consideration. Should some
factors be added or deleted? Should
more emphasis be placed on some
factors than others? How should the
cosj-effectiveness, cost-benefits, or
aflordability of controls be considered
when establishing appropriate emission
standards to provide an ample margin of
safety? EPA also requests comments on
whether the factors were appropriately
applied to the nine source categories
that were reviewed.
It Is the intent of the Act that control
technology or operational practices be
used to control emissions. Buying land
to expand the site of the site or building
higher stacks to reduce exposure to
nearby individuals may not be used
where other emission control devices or
operational procedures are reasonably
available. However, there are
r-ldionuclides, principally radon, which
present significant risks and for which
emission controls may not always be
reasonably available. As a last resort in
such cases. EPA has decided to propose
standards achievable through dispersion
techniques.
II. Department of Energy Facilities
{OOE)
A, General Description
DOE administers many facilities that
emit radionudides to air. These facilities
are Government owned but are
managed and operated for DOE by
private contractors. Operations at these
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Federal Register / Vol. 48, No, 67 / Wednesday, April 6, Ii83 / Proposed Rules
facilities include research and
development, production and testing of
nuclear weapons, enrichment of
uranium and production of plutonium
and other fissile materials for nuclear
weapons, reactors, and other purposes,
and processing, storing, and disposing of
radioactive wastes. These facilities are
on large sites, some of which cover
hundreds of square miles in mostly
remote locations, and are located in
about 20 different states. Sorae of the
smaller facilities resemble typical
industrial sites and are located in
suburban areas.
Each facility differs in emission rates,
site size, nearby population densities,
and other parameters that directly affect
the dose from radionuelide emissions.
Many different kinds of radionuclides
are emitted to air. Six sites have
multipurpose operations spread over
very large areas. About a dozen sites
are primarily research and development
facilities, located in more populated
areas. Reactor and accelerator
operations at these sites may release
radioactive noble gases and tritium;
other operations may release small
amounts of other radionuclides. Several
facilities are primarily engaged in
weapons development and production
and may release small amounts of
tritium and cretain long-lived
radionuclides. Finally, two sites are
dedicated entirely to gaseous diffusion
plants that enrich uranium for use in
utility electric power reactors and for
defense purposes. They primarily emit
uranium,
B, Estimates of Dose and Risk
At 15 of the 25 DOE facilities, which
are considered as a group in the
Background Information Document
because of their relatively small health
impact, the doses to the nearby
individuals ar estimated to be
considerably less than l milllrem per
year (mrem/y), The collective dose to
the populations living around the sites is
also low, no higher than about 10
pmon-rem as the result of l year of site
operation. The health risk associated
with this group is correspondingly low.
The maximum lifetime risk to the most
exposed individual is estimated to be
Jess than 10 in 1,000.000 and the impact
on the population is estimated to be less
than 1 potential health effect per 100
years of operation. These estimates
were developed using methods and
assumptions discussed in Unit I.C. of
this notice,
A second group of 13 facilities, those
with the largest emissions of
radionuclides. were studied in more
detail. They included the following
major sites; Argonne National
Laboratory, Brookhaven National
Laboratory, Feed Materials Production
Center, Fermi National Accelerator
Laboratory, Hanford Reservation, Idaho
National Engineering Laboratory,
Lawrence Livermore Laboratory, Los
Alamos National Laboratory, Oak lidge
Reservation, Paducah Gaseous Diffusion
Flint, Portsmouth Gaseous Diffusion
Plant. Rocky Flats Plant, and the
Savannah River Plant
The highest doses to individuals are
projected for Los Alamos national
Laboratory (about § mrem/y to all
orf ans]. Oak Ridge Reservation {about
50 mrem/y to lung and 8 tnrem/y to the
bone] the Paducah Gaseous Diffusion
Plant (about 7 mrem/y to bone and 8
mrem/y to the lung), the Portsmouth
Gaseous Diffusion Plant (about 11
mrem/y to bone, 7 mrem/y to lung and 2
mrem/y to thyroid), Feed Materials
Production Center (about 88 mrem/y to,
lung and 28 mrem/y to bone), and
Savannah River Plant (about I mrem/y
to most organs and 5 mrem/y to the
thyroid). The corresponding doses to
large populations ranged up to about 200
person'rem to the lung per year of site
operations. The corresponding
maximum lifetime risk to the most
exposed- individual is estimated to be
less than about 2 In 10,000, while the
total risk to populations surrounding all
13 sites is estimated to be less than 1
potential health effect per 15 years of
operation.
All risk estimates for DOE facilities
were developed using methods and
assumption discussed in Unit LC. of this
notice. It is important to recognize that
the actual risk to specific individuals
may differ greatly from these estimates
because the circumstances involving the
actual exposure may differ significantly
from the assumptions used to make the
estimates,
C. Emission Control Technology
Emissions from DOE facilities are, in
general well controlled as part of a long-
standing DOE program of systematically
upgrading emission controls when
practical. High-efficiency filters, usually
in series when large amounts of
radionuclides art processed, are used to
control particulate emissions. At some
facilities, there are processes that
discharge radioactive noble gases and
tritium mixed with large volumes of air.
For these cases, control technologies to
remove the boble gases and tritium are
usually not feasible.
At the Oak Ridge site, the highest
doses to nearby individuals are mostly
caused by uranium-234 and uraftium-238
emissions from the Y~42 plant, a facility
that has fabrication operations using
enriched uranium, Particulate emissions
from this facility are controlled by
scrubbers, prefilters, doth bag filters, or
high-efficiency particulate filters. At the
Feed Materials Production Center, the
highest projected doses to nearby
individuals are due to emissions.of
uranium-234 and uranium-238 from
fabrication operations using uranium.
There is also high exposure to radon
decay products due to wasfes containing
radium-226 that are stored on this site.
Particulate emissions are controlled by
cloth bag filters or scrubbers but can be
reduced further by additional high-
efficiency filters or improved scrubbers.
Waste tanks can be sealed to prevent
the escape of radon.
O. The Pfoposed Standard
EPA Is proposing that emissions of
radionuclides from DOE facilities be
restricted to the amount that would
cause a dose equivalent rate of 10
mrem/y to the whole body and 30
mrem/y to any organ of any individual
living nearby. For most practical
purposes, compliance with this standard
%vould be determined by calculating the
doese to persons assumed to be living at
the site boundary.
Consistent with the principles
embodied in Federal Radiation
Guidance to keep exposure to radiation
as low as practical, it is EPA's intent
that facilities subject to the DOE
standard shall use best available
technology even if compliance is
possible with a lesser degree of control.
This means that operators should
periodically evaluate radionuclide
emissions to air and reduce them to as
low a level below the standard as is
reasonably possible. This also means
that the facilities now well controlled to
levels considerably below the proposed
standard should not relax their emission
controls and that new facilities should
use best available emission controls.
To determine if (he standard is being
implemented In 3 manner that keeps
exposure as low as practicable, EPA is
proposing a reporting requirement. DOE
shall submit to EPA a concise annual
report which includes the results of
monitoring emissions, dose calculations,
and discussions of DOE's programs for
maintaining airborne releases of
radionuclides as low as practicable.
Much of this information is currently
being collected; for example, emission
data are reported by DOE'S effluent
information systems and annual site
reports describe recent and planned
improvements in emission controls.
Therefore, EPA believes the burden of
this reporting is reasonable. This
information will be reviewed by EPA in
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Federal Hegister / Vol. 48, No. 67 / Wednesday, April §, 1983 / Proposed Roles
15081
carrying out its compliance
responsibilities.
The proposed emission standards of
10 mrem/y whole body and 30 mretn/y
to any organ were selected by
considering highest existing emissions
from those major D0E facilities where
best available technology is used and
considering the level to which emissions
would be reduced by applying
additional controls to other facilities-
Uniform standards for DOE facilities
could not be set lower than these valaes
because emissions from some major
DOE facilities cannot, as a practical ^
matter, be reduced further without
closing major operations at the facilities*.
Thest DOE facilities provide substantial
benefits in the areas of electrical power
generation and national defense. The
consequence of a more restrictive
standard would be to eliminate some of
these beneficial activities.
Consequently, the risks associated with
the proposed standard are not
unreasonable. Those few DOE facilities,
tending to have emissions greater than
this proposed limit can; in EPA's
judgment, reduce their emissions using
available technology or work practices.
EPA believes that the proposed
standard would be met if the following
plcnts upgraded their control
technology; [I] Oak Ridge Y-1Z plant
($10 million capital oasis) (2) Feed
.Materials Production Center (315 million
capital costs).
The dose allowed by the proposed
standard is a factor of 50 lower than the
current upper limits now «sed by DOE,
These current upper limits art based on
the 1980 recommendations of the
Federal Radiation Council, although the
Federal Radiation Council admonished
Federal agencies to establish standards
that would reduce emissions to as low
as practical below the upper limits.
Actual public exposure to radiation due
to releases froa COE facilities has been
far below the 1960 Federal Guidance
levels because of the DOE practice of
limiting emissions to as low as.
practicable levels. Since the proposed
standard is much more restrictive than
the 1960 guidance, it will limit radiation
doses to low levels. In practice. EPA
expects that most DOE facilities will
Operate well below the proposed
standard.
EPA estimates the actual lifetime
individual risk associated with the
proposed standard to be at the most
about 2 in 50.000 when facilities are
complying with the standard. EPA
believes that the proposed standard and
the reporting requirement will protect
the public living around DOE facilities
with an ample margin of safety. The
uncertainty associated with estimates of
radiation doss and risk is discussed in
Unit tC. and H.B of this notice.
EPA requests comments on the
proposed values and the methodology
used in arriving at them.
E, Alternatives to the Proposed
Standard
EPA considered proposing emission
limits in units of curies per year (Ci/yJ
for etch radJonuclide, with secondary
corrections for particle size, lung
clearance class, and other suck factors.
This approach was rejected because it
would require very detailed and
complex emission limits for each DOE
facility to be as protective of public
health as the proposed standard. In
EPA's judgment this would be so
complex and difficult as to be infeasible.
The Agency considered proposing
higher values than the proposed dose
limit. We believe that many of these
facilities are achieving the proposed
standard at current operating levels. For
the few cases where additional controls
are needed to meet the standard, the
technology appears available and
effective and is not unreasonably
expensive to purchase or operate. The
protection offered by the proposed
standard appears achievable, and we
have not identified any good reason for
accepting a lesser degree of protection.
Lower values were considered. Such
limits, would be extremely costly or
could force the closure of raajor
operations of benefit to the country,
possibly at several sites. The possible
small additional reduction of dose and
risk to a few individuals is not sufficient
to justify such severe action.
Emission limits that would control
dose to the general population rather
than individuals were considered. In
particular, EPA considered emission
limits for long-half-life radionuclides
such as tritium, carbon-14. krypton-85,
and iodine-129. These kinds of
radionuclides may cause population
doses that are more significant than the
doses these radionuclides cause to
nearby individuals. EPA decided not to
propose this kind of standard. For DOE
facilities, population doses from these
radionaclides are small; the highest of
these small doses are caused by
emissions of tritium for which control
technologies are not effective.
Consequently, proposing emission
Standards for long-half-life
radionuelides at existing DOE facilities
would not serve a useful purpose.
Different emission limits were
considered for existing and new DOE
facilities and for specific groups of DOE
facilities, rather than setting uniform
standards for all DOE facilities. Such a
strategy would permit more restrictive
standards for certain DOE facilities,
although not for all of them, at the cost
of having to develop a much more
.complex standard. Rather than do this,
EPA will rely on existing Federal
Guidance to all Federal agencies to
ensure that exposures are kept as far
below the. proposed standard as
practicable and has added a reporting
requirement to this end. This should
provide, in practice, the same measure
of emission control, EPA requests
comments on the desirability of setting
separate standards for different
categories of DOE facilities.
EPA considered the alternative of
proposing the standard in the form of a
risk-equivalent, whole-body dose, using
methodology similar to that recently
recommended by the International
Commission on Radiation Protection,
The principal advantage is one of equity;
that is, the emissions from each facility
are limited on the basis of causing
equivalent levels of risk. A disadvantage
of this alternative is that the proposed
standard would have to be reduced from
10 mrera/y to about 5 nsrem/y to
maintain a comparable degree of
protection wiih the 30 mrem/y limit to
any organ. Some sources could not meet
such a standard using currently
available technology. The Agency
particularly requests comment on the
use of the whole-body, risk-equivalent
dose method as an approach to selecting
emission standards,
EPA considered requiring the
proposed standard to be met at a site
boundary in all cases, even if there are
good reasons why people are not likely
to be at that location, but decided not to
because this would be unrealistic. EPA
requests comments on where the
standard should apply.
F. Implementation of the Proposed
Standards '
The standards will be implemented by
DOE pursuant to the Memorandum of
Understanding between EPA and DOE.
EPA will provide oversight to ensure
that implementation procedures are
appropriate. The standard should be
implemented using pathway and dose
calculations based on EPA's codes or,
alternatively, on modeling techniques
which, in EPA's judgment, are as
suitable for particular applications as
the EPA codes.
II. NRC Licensed Facilities and Non-
DOE Federal Facilities
A. General Description
This category of facilities
encompasses a wide range of activities
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15082 Federal Register / Vol. 48, No. 67 / Wednesday, April 6, 1983 / Proposed Rules
Including research and test reactors,
shipyards, the radiopharmaceutical
industry, and Other industrial facilities.
For purposes of this proposed rule, EPA
excludes facilities that are part cf the
uranium fuel cycle. The category
includes both facilities licensed fay NRC
and facilities licensed by a State under
an agreement with NRC, These facilities
number in-the tens of thousands and are
located in all 50 states. The principal
differences among these various types of
activities are their emission
characteristics and rates, their siies,
and the population densities of the
surrounding areas. The following
discussion provides illustrative
examples.
There are a wide variety of designs of
research and test reactors, and they
operate over a range of power levels
from near zero to approximately 10
megawatts. They emit primarily argon-
41 and tritium at rates ranging from less
than 1 Ci/y of each radionuelide tip to
several thousand Ci/y of argon-41 and
several hundred Ci/y of tritium. They
are most often located at or near
universities,
The radiopharmaceutical industry
currently produces about 85 different
radioneulides for a variety of uses in
hospitals and clinics. In most cases,
emissions of iodine—125 and iodine-131
cause the highest organ (thyroid) doses
to nearby individuals because: (1) They
are emitted in the largest quantities, (2J
environmental pathways bring them into
contact with man, and (3} the thyroid
concentrates iodine. Emissions occur at
radiopharmaceutical manufacturing
sites, hospitals, and sewage treatment
plants receiving hospital wastewater.
There art many other industrial uses
of a number of different radionuclides
that result in emissions to air, including
the manufacture of industrial gauges,
static eliminators, radiographic devices,
and certain commercial products (e.g.,
self-illuminating watches and smoke
detectors). Most of the industrial uses of
radionuclides involve production of
sealed (encapsulated) sources. Once
their manufacture is completed, these
sealed sources do not emit
radionuclides.
B, Estimates of Dose and Risk
The vast majority of NRC licensed
facilities and non*00E Federal facilities
emit relatively small quantities of
radionuclides, which cause
correspondingly low doses SO people
living nearby. Most such facilities cause
maximum radiation doses of less than i
mrem/y; the total dose to the population
living around a site rarely exceeds I or 2
person-rein per year of operations. The
maximum corresponding lifetime risks
of such exposures are estimated to be
less than 1 in 50,000 for the individuals
receiving the highest doses, and the total
risk to the population surrounding a
typical facility should be less than about
1 health effect per 500 years of
operation.
These estimates were developed by
using methods and assumptions
discussed in Unit I.CL of this notice. It is
important to recognise that the actual
risk to specific individuals may differ
greatly from these estimates because the
circumstances involving the actual
exposure may differ significantly from
the "assumptions used to make the
estimates,
C. Control Technology
Some NRC-licensed facilities emit
argoiMii and tritium mixed with-large
volumes of air. For this type of facility,
virtually all of the dose is caused by
argon-41. Demonstrated treatment
technology to reduce argon-41 emissions
is not available because argon is S noble
gas and cannot be filtered or easily
trapped. However, design features,
operating procedures, and equipment
maintenance can be used to minimize
formation of argon-41 in these reactors.
For example, since air contains a smalt
percentage of argon-40, areas in which
air 19 exposed to neutrons generated by
the reactor are sources of argon-41-
when argon-40 absorbs a neutron during
reactor operation. In some situations.
these areas can be purged with an inert
gas to reduce the amount of argon-40
available before starting up the reactor.
In other cases, sealing air leaks will
reduce the amount of argon-41 that
would be produced.
• Most facilities emitting dust to which
radionuclides art attached use
conventional particulate removal
technology, such as fabric filters.
electrostatic precipitators, scrubbers, or
high-efficiency particulate air filters,
D. The Proposed Standards
EPA is proposing that emissions of
radionuclides from NEC-licensed
facilities and non-DDE Federal facilities
be limited to that amount that would
cause a dose equivalent of 10 mrem/y to
any organ of any individual living
nearby. Uranium fuel cycle facilities and
all particle accelerators are specifically
not covered by this standard for reasons
discussed Unit VI! of this notice.
In proposing this standard, EPA
examined emission levels from facilities
In this category and estimated the dose
these emissions cause for people living
nearby. The highest doses are caused by
research and test reactors emitting
principally argon-41. The dose
associated with the operation of these
facilities is low md cannot be
significantly reduced without major
redesign and and reengineering of these
facilities. Therefore, EPA has decided to
proposed a standard at a level that can
be met by existing facilities if they
continue to use good management and
operational controls to limit their
emissions.
EPA believes that the proposed
standard protects public health with an
ample margin of safety. EPA estimates
the risk associated with the proposed
standard to be the same as for current
practice for the individual receiving the
highest dose. The uncertainty associated
with estimates of risk is discussed la
Units. 1C, and III. B. of this notice,
EPA requests comments on the
proposed standards and the
toethodology used in deriving it
R Alternatives tg the Proposed
Standard
The Agency considered higher and
lower dose limits than the one being
proposed. Higher values were rejected-
because the proposed standard is
currently being met by all facilities in
this group. A lower limit was rejected
because the dose associated with these
emissions is very low and EPA does not
believe it is reasonable to aet a lower
standard and force these facilities to
close or reduce their hours of
operations,,-
EPA considered not proposing a
standard for this category of facility
because the dose from the operations is
generally very low. The Agency rejected
this alternative because of the potential
impact of new facilities or modifications
to existing facilities; a standard will
ensure that no facilities will emit
radionuclidea at unreasonably high
levels.
EPA also considered requiring that
these facilities submit reports
documenting that their emissions are as
low as practicable; as is being proposed
for DOE facilities. Such a requirement
would impose a very large paperwork
burden on government and industry.
Facilities in this category number in the
tens of thousands. For EPA to implement
such m requirement for this category
would require monitoring and reporting
by thousands of facilities and a
substantial effort on the part of .\RC or
EPA to review the reports. This
considerable effort would help ensure
that emissions remain very low.
However, because the risk associated
with the proposed standard is already
low, EPA does not believe the
paperwork burden on government and
industry is justified Furthermore. EPA
expects that facilities in this category
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Federal Register / Vol. 48. No. 67 / Wednesday, April 6. 1983 / Proposed Rules 1SQ83
will, in practice, keep emission levels as
low as practicable, both, to ensure
compliance with the proposed standard
and as a matter of good radiation
protection principles when dealing with
hazardous materials.
F. Implementation of the Proposed
Standards
For NIC licensed facilities. NRC will
implement the standards subject to EPA
oversight to ensure there is compliance
with the standard, as is specified in a
Memorandum of Understanding
between EPA and NRC (45 FR 72980),
Ira pi amenta i Jon will follow the
established NRC practice, which is
based on a review of control measures
used by licensees and their effectiveness
as determined by generic assessments.
For non-DOE Federal facilities, EPA
will ensure compliance with the
standards, EPA's implementation will
use the models AIRDQS-EPA and
RADRJSK to perform pathway analysis
and to calculate dose equivalents.
IV, Underground Uranium Mines
,-L Cenero! Description
Uranium mining involves the handling
• if large quantities of ore containing
aranium-238 and its decay products. The
concentrations of these radionuclides in
ore may be up to 1,000 times their
concentration in other rocks and soils.
After mining, the ore is shipped to a
uranium mill where the uranium is
separated for subsequent use in nuclear
power reactors.
Uranium mining is generally carried
uut by either surface (open pit] or
underground mining methods, depending
oft the depth of the ore deposit. In 1881.
there were 167 underground mines and
CO open pit mines in operation in tht
United States. These mines accounted
for about SO percent of the uranium
produced in this country.
All uranium mining in the Unittd
States now takes place in western
States. In general, the mines are located
in relativelyjremotc, low population
ereas. In 1981, about 70 perceirt of
domestic uranium ore production took
place in New Mexico, Wyoming, and
Texas",
EPA has evaluated radionuclide
emissions from uranium mining
activities. These evaluations show that
r.idon-222 is the most significant
radionuciide emitted to air, Radon-222 is
released to air from underground mines
in relatively high concentration through
a series of ventilation shafts installed at
appropriate locations along the mine
haulage ways. These ventilation shafts
Provide sufficient air exchange in the
working areas of the mine to keep the
miners* exposures to radon decay
products below the permissible limits. A
recent study of 27 underground mines
showed that radon-222 emissions to air
from individual vents ranged from 2 to
9,000 Ci/y with an average of 900 Ci/y.
The number of vents per mine ranged
from 2 to 15 with an average of 6 vents
per mine. The radon-222 released
through these ventilation shafts can
cause significant increases in the radon-
222 concentration in ambient air in the
Vicinity of the mine vents.
EPA's evaluation of releases of radon-
- 222 from uranium mines shows that
radon-2E2 is released from surface
mines in considerably smaller quantities
and to more dilute concentrations than
from underground mines. Therefore,
radon-222 emissions from surface mines
causes only small increases in the
rmdon-222 concentrations in ambient air
near the mines and concerns for the
health of people near uranium mines is
greatest for people living near
underground mines,
B, Estimates ofExposiife and Risk
Individuals living near underground
uranium mines can be exposed to high
levels of radon-222. This exposure
generally occurs in structures built
around the mines. Radon-322 enters the
building and decays into other
rsdionuclides which become attached to
dust particles in the air. The
concentration of these radionaclidts
build up in the air within the structures*
EPA estimated tht potential detriment to
human health because of radon-222
emissions from uranium mines using the
general assumptions discussed ia Unit
I.C, of this notice. It is Important to
recognize that the actual risk to
individuals may differ greatly from these
estimates because the circumstances
involving the exposure may differ
significantly from the assumptions used
to make the estimates. Further, people
need to be occupying a structure and not
just standing outdoors for these
estimates to be applicable.
It is estimated "that an individual
living 500 meters in the predominant
wind direction from a large underground
uranium mine will be exposed to a
radon*222 concentration, of 1 to 2
picoeuries per liter (pG/ll above
background. Continuous exposure to
indoor radon decay product
concentrations (0.007-0,014 working
level (WL)) produced by this radon-222
level might result in an increased
lifetime risk of 1 to 2 in 100, although in
areas where there are many mine vents
clustered relatively close together, the
risks-could be as high as an order of
magnitude greater. (A working level is a
unit used to measure exposure to radon
decay products).
Collective exposures for populations'
living near uranium mines are relatively
low because these mines generally are
located in low population areas. For
example, the population risk due to
radon-222 emissions from a large
underground mine is estimated to be
extremely small {about l health effect
per 30 years of operation of the mine).
Consequently,- for underground uranium
mints, the exposure to the general
population is of considerably less public
health concern than the exposure for the
people that iive very close to the mine
vents.
C. Control Technology
There are 110 radon-222 emission
control systems now in use in
underground uranium mints. However,
several methods for reducing the radon-
222 concentration in mine air are
available and have been used or tested
for controlling radon-222 decay product
concentrations in the mine itself. These
methods, which primarily involve
preventing radon-222 from entering the
mine air through the use of sealants on
the mine walls, bulkheading or
backfilling the mined-out stopes, and
mine pressurization can also reduce the
radon-222 emissions to the outside air.
EPA has carried oat engineering
evaluations of the cost and effectiveness
of some of these methods in a
hypothetical mine. These evaluations
showed that such control methods
would be relatively costly and not very
effective. The study predicted radon~222
emission rtductio&s from 14 to 49
percent at costs from S0.30 to $4.70
dollars per ton of ore mined.
Based on available information. EPA
has concluded that no practical
technology now exists for achieving
satisfactory reductions in radon-222
emissions to air from underground
uranium mines. The most effective
procedure for limiting exposure to
individuals is to provide for greater
dispersion of the released radon-222,
The Act indicates a preference for
avoiding this type of control action to
reduce health risks. However, in this
situation, traditional emission control
methods do not appear to be sufficiently
effective in reducing the human health
risks posed by release of rados-222 from
underground uranium mine vents.
D. The Proposed Standard
EPA is proposing a standard that will
limit the annual average mdon-222
concentration in air due to emissions
from an underground mine to O,2 pCi/i
above background in any
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Federal Register / Vol. 48. No. 67 / Wednesday. April 6.1983 / Proposed Rubs
area. An unrestricted area is defined to
be any area not under the control of the
mine owner or a government agency,
Under this proposed standard, for a
typical, large underground mine using
the modeling assumptions previously
described, we estimate the lifetime risk
to an individual will be on the order of
about 1 in 500. For a case in which many
mines are located close together, studies
which sstimste the hazard based on a
lifetime exposure show that the
potential risks would be higher.
However, uranium mines have a limited
useful lifetime, usually 5 to 15 years,
which limits the period when radon-222
would be released. Further, several
olher assumptions used in these studies,
such as the period of occupancy of the
structure, are likely to be less severe in
real cases. These factors are expected to
make the actual remaining risk to
individuals less than 1 in 500, possibly
by one or two orders of magnitude,
depending on the specific
circumstances.
EPA chose a standard of 0.2 pCi/1
because higher values did not provide
sufficient protection of public health,
particularly when many mines are
located close together. Values lower
than the proposed standard were judged
to be impractical bf cause of the cost
and difficulty in controlling additional
land and the expense associated with
• other control measures compared to
their cffectivenss. EPA believes that the
risks associated with the proposed
standard are ROt unreasonable in
comparison to the cost of additional
control*
The standard can be met by one of the
following procedures; (1) Reducing the
percentage of time the mine operates, (2)
increasing the effective height of the
release, and (3) controlling additional
land. EPA expects that the least
expensive way to meet the standard is
for the the mine operator lo control the
land around the mine so that people do
not live in houses on tht land, EPA
believes that, on the average,
compliance with the proposed standard
can be achieved by controlling land
within 2 kilometers of the mine vents,
The Cost to meet the standard by
purchasing surrounding land and
structures is estimated to be about 4
million dollars per year. This estimate
was determined from an evaluation of
the cost to control land within 2
kilometers of 29 large mines
representing about SOW of the
underground uranium mine or
production
Based on 1981 production values, this
nost represents a SO-30 per pound
increase in the cost of producing
uranium. This represents a i% increase
in production costs. Although the costs
for the smaller mines accounting for the
remaining ore production are not
included in the estimate, these costs will
be relatively small because the radon-
222 emissions from these mines are
expected to be small.
Owners and operators of underground
uranium mines will be required to keep
records of radon-222 emissions and
radon-222 concentration projections
consistent with other actions under the
Act
EPA requests comments on the
proposed concentration limit of 0.2 pQ/
I. EPA believes that the proposed
standard is the most practical and
effective way to limit the potential risk
to individuals due to radoa-222
emissions from underground uranium
mines.
£. Alternative Standards
The development of standards for
uranium mines is more difficult and
complicated than for other sources
emitting radionuclides into air,
Therefore, the Agency requests public
comment on other possible options for
standards. In particular, comments are
requested On appropriate limits, cost,
feasibility, and significance for public
health for the following options:
Option 1: Land Control Standard. This
type of standard would establish an
exclusion area of fixed distance from a
mine vent. This area would be under the
control of the mine owner or a
government agency to prevent excessive
exposure to individuals.
Option 2; Work Practice Staadard
This standard would include
requirements for "use of one or more of
the following techniques to reduce radon
emissions: bulkheading worked~out
Slopes (including the use of charcoal
absorbers on bleeder pipes), backfilling
worked-out slopes, and using sealants
on mine walls,
Option 3: Btfiission Stanford, This
type of standard would establish an
emission limit in curies per year of
radon-222 from a mine vent as a
function of the distance from the vent to •
the nearest unrestricted area. The
emission limit would be set at a value
that would keep the radon-222
concentration in ambient air in
unrestricted areas below some
predetermined value above background.
V. Elemental Phosphorus Plants
A General Description
About 10 percent of the phosphate
rock mined in the United States is used
to produce elemental phosphorus.
Elemental phosphorus is used primarily
for the production of high-grade
phosphoric acid, phosphate based
detergents, and organic chemicals. In
1377, approximately 285,000 metric ton*
of elemental phosphorus were produced
from 4 million metric tons of phosphate
rock.
Phosphate rock contains appreciable
quantities of uranium and its decay
products. The uranium concentration of
phosphate rock ranges from about 20 to
200 parts per million (ppmj, which is 10
to 100 times higher than the uranium
concentration in most natural rocks and
soil (2 ppm). The significant
radionuclides present in phosphate rock
are tiranium-238, uraniuai-34, thorium-
230, radium-226, radon-222, lead-210,
and polonium-2lQ, Because phosphate
rock contains elevated concentrations of
these radionuqlides. handling and
processing this material can, via dust
particles, release radionuclides into the
air. More importantly for elemental
phosphorus plants, heating the
phosphate rock to high temperatures in
calciners and electric furnaces can
volatilize lead-210 and polonsum-21Q,
resulting in the release of large
quantities of these radionuclides in to
the tir.
There are eight elemental phosphorus
plants in the United States; these plants
are located in Florida, Idaho, Montana,
and Tennessee. EPA measurements at
three of these plants show that
polottium-klO and lead-210 are the
radionuclides released from these plants
in largest quantities. Most of these
emissions occur in calciner stack
exhausts. Based on these measurements,
it is estimated that a large plant
processing phosphate rock containing 25
picocuries per gram of uranium-238 and
its decay products and using low energy
scrubbers on its calciner exhausts would
release about 4 curies of polonium-210
and 2 Curies of lead-210 per year into the
air. Several of the presently operating
elemental phosphonii plants may be
releasing comparable quantities of
pclonium-210 and lead-210, and these
emissions would represent the largest
quantity of alpha-emitting redionuclides
released as particulates into the air by
any type of facility in the United States.
B. Estimates of Dose and Risk
The most significant hazard
associated with radionuclids emissions
to air from elemental phosphorus plants
is the radiation dose received by
individuals living near those plants, EPA
estimates that the radicnuclide
emssions. primarily polonhun-2iQ and
lead-210, from a large elemental
phosphorus plant will cause radiation
doses of 45 mrern/y to the kidney and 38
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mrcm/y to the lung of the most exposed
individual living near the plant. The
lifetime risk to the maximally exposed
individual associated with these doses
is estimated to be about 1 in 10,000.
The risks to the populations living
near elemental phosphorus plants are
relatively low. EPA estimates that the
potential health risk to the population
living around a large plant is about 1
health effect per 100 years of plant
operation and that the total risk from
radionuciide emissions from all
elemental phosphorus plants is about 1
health effect per 20 years of operation. ,_
These estimates were developed using
methods and assumptions discussed ill
Unit I.C. of this notice- It is important to
recognize that the acutal risk to specific
Individuals may differ greatly from these
estimates because the circumstances
involving the exposure may differ
significantly from the assumptions used
to make the estimates,
C. Control Technology
Particulate emissions from calciner
exhausts at elemental phosphorus plants
are controlled through the use of wet
scrubbers. Most plants use either Spray
towers or low-energy venturi scrubbers.
Such systems are estimated to control
particulate emissions lo about 0,5 to 1.0
pound per ton of rock processed and are
about 80 to 90 percent efficient for
removal of polonium~210. One plant
operates with two venturi-lifce scrubbers
in series. Such a system should control
particulate emissions to about 0.1 pound
per ton of rock processed and is about
98 percent efficient for removal of
potonium-210.
EPA has estimated the cost of
installing high-energy venturi scrubbers
on calciner stacks at large elemental
phosphorus plants now operating with
spray towers or low-energy scrubbers.
The capital cost per plant for installing
these scrubbers is about S3 million, and
the annual operating cost is $1.5 million,
A high-energy venturi scrubber is
expected to be at least 98 percent
efficient for poionium-210 removal and
to reduce the emissions of this
radionuciide for a large plant to less
than 1 Ci/y, Lead-210 will be controlled
at least as well because the scrubbers
will remove lead with at least equal
efficiency.
D. The Proposed Standard
EPA is proposing that the emissions of
poionium-210 in the calciner off-gases at
elemental phosphorus plants be limited
to 1 Ci/y. EPA believes the use of best
avuilablf technology at these facilities
can achitve this standard. Limiting the
polonium-210 emissions also effectively
limits the lead-2iQ and other
radJonuclide emissions in the calciner
off-gases, this standard will keep the
radiation doses to individuals living
near these plants to less than 10 mrem/y
to the lung and to less than 15 mreni/y
to the kidney. The lifetime risk
associated with these doses is less than
3 in 100,000, EPA believes this will
protect the Individuals living nearby
with an ample margin of safety. The
assumptions and uncertainties
associated with estimates of risk are
discussed in Units I.C. and V.B. of this
notice.
Complete information is not available
on the poloniuin-210 emissions from all
elemental phosphorous plants.
Therefore, some uncertainty exists
' regarding the number of plants that
would need to retrofit emission control
systems. However, based on presently
available information, EPA estimates
that no more than two plants would
need to install additional control
systems to meet the proposed standard,
These would be the large-capacity
plants processing high-radionudide-
content phosphate rock. Installation of
high-energy venturi scrubbers on the
calciner exhausts of two plants would
result in a capital expenditure of about
$6 million and annual operating costs of
S3 million per year.
Under the proposed standard, owners
or operators of elemental phosphorus
plants will be required to fa) measure
the polonIum-210 emissions from their
calciner stacks and to report the results
of these tests to EPA and (bj
continuously monitor the pressure drop
across their calciner scrubbers and to
maintain records of these measurements
for a minimum of two years,
EPA requests comments on the
proposed values and the methodology
used in arriving at them,
£1 Alternatives to the Proposed
Standard
The Agency considered proposing
higher or lower values then l Ci/y,
Higher values did not seem justified
because they would either not
significantly reduce the radiation doses
to individuals living near these plants or
would cost just as much to implement as
the proposed standard. Lower values
were also considered, but available
information indicates that additional
control technology is not feasible to
meet lower levels,
The Agency also considered a
standard expressed as curies/metric ton
of phosphate rock processed. However,
this type of standard may require
emmission control retrofit by one or
.more additional plants even though their
emissions of poionium-210 would be
significantly less than I Ci/y. Since the
primary purpose of the standard is to
limit the annual radiation doses to the
most exposed individual living near
these plants, the Agency concluded that
an annual emission limit, rather than an
emission limit per unit of rack
processed, is the more appropriate form
of the standard.
VL Sources for Which Standards Are
Not Proposed
EPA has identified several source
categories that emit radionuclides to air
for which standards are not being
proposed. These emissions comprise
radionuclides that occur naturally in the
environment but are released to air due
to industrial processes. In addition to
these sources, EPA is not proposing
emission Standards for uranium fuel
cycle facilities, uranium mill tailings,
management of high level radioactive
wastes, and low energy accelerators.
The reasons for these decisions are
discussed in the following paragraphs.
Additional supporting information may
be found in the Docket and in the
Background Information Document,
Estimates of risk used in this analysis
were developed using methods and
assumptions discussed in Unit I.C. of
this notice. It is important to recognize
that the actual risk to specific
individuals may differ greatly from the
• estimates becaust the circumstances
involving the actual exposure may differ
greatly from the assumptions used to
make the estimates,
A. Coal-Fired ffoilers
Large, coal-fired boilers are used by
utilities and industry to generate
electricity and by industry to make
process steam and to heat water for
space heaters and industrial processes.
When these boilers are operating, trace
amounts of uranium, radium, thorium,
and decay products of these
radionudjdes that are present in coal
become incorporated into the fly ash
and are emitted along with the
particulates into the air. Technology that
removes particulates will, therefore, also
limit radionuciide emJssions.
Particulate emissions from new utility
boilers are controlled under Section HI
of the Act (43 FR 42154. September 19,
1978, revised by 44 FR 33513. June 11.
19?9). These New Source Performance
Standards (NSPS) require utility boilers
constructed after September 19,1978, to
have best available technology that
limits particulate emissions to 13
nanpgrams per Joule frig/J) (0-03 pound/
million Btu). To meet this emission
standard, electrostatic precipitators
(ESPs) or fabric filter systems are
usually installed. Doses from utility
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Federal Register / Vol. 48. No. 67 / Wednesday. April 6. 1983 / Proposed Rules
boiler radionuclide emission! under
NSPS are low, less than 1 rnrem/y to
any organ, and there is no practical way
to reduce them further since best
available technology is already being
used. Further reduction in emissions
Would require a second fabric filter or
ESP in series with the first; this would
be unreasonably expensive for the
emission reduction achieved. Thus,
radionuelide emission standards for new
utility boilers would be either redundant
or, if more restrictive, prohibitively
expensive.
Participate emissions from new large
industrial boilers are controlled by
NSPS that limit participate matter to 43
ng/J (0,1 pound/million Btu). EPA plans
to propose NSPS for smaller industrial
boilers also: draft proposed limits have
been circulated for comment These
standards should reduce particulatt
emissions to low levels and should
correspondingly reduce doses to nearby
individuals from radionuclide emissions
to less than 1 mrera/y to any organ.
With NSPS in place, radionuclide
standards for industrial boilers would
be redundant.
Existing utility and Industrial boilers
are regulated for particulate emissions
by State Implementation Plans (SIPsJ
required by the Act, Limits vary for
specific plants, but, in general, SIPs
require large boilers located to
populated areas to be well controlled
with ESPs, Preliminary information
indicates that retrofitting existing utility
boilers to further reduce radionuclide
emissions would cost approximately SIS
billion for capital improvements and S3
billion a year to operate them. Total
retrofitting of the industry with best
available technology would reduce the
estimated potential health effects by
about H to 2 per year. For industrial
boilers, the costs are about $3 billion for
capital improvements and $0,7 billion to
operate them. Total retrofitting of the
industry with best available technology
would reduce the estimated potential
health effects by about 1 every three
years. For both utility and industrial
boilers, the costs are judged to be
unreasonable in comparison to the
reduction in dose and risk that would
result.
The amount of radionuelides that
could potentially be emitted by coal-
fired boilers is strictly limited by the
amount of uranium and thorium in the
incoming coal. EPA has no reasons,
therefore, to expect that massive
releases of radionuclides will occur or
that current emission rates will increase
significantly. Under the current Federal
and State regulatory programs,
emissions should slowly decrease as old
boilers are replaced.
In summary, EPA is not proposing
standards for coal-fired boilers because
existing emission controls that limit
particulate releases also limit
radionuclide releases. The risks to
nearby individuals and the total risks to
populations after application of controls
already required are not large when
compared to the cost of additional
control technology, There Is no potential
for emissions to increase due to the
limited amounts or radionuclides within
the coil; rather, overall emissions will
decrease with time as old plants are
replaced with new ones with improved
emission controls as required by the
NSPS for particulate emissions,
EPA did consider the possibility that
boilers may be using coal with
radionuclide content that is significantly
above average or that existing boilers
may be operating in a manner that
causes elevated emissions of
radionuclides. If this is the case, there
could be a subcategory-of coal-fired
boilers for which it would be
appropriate to issue an emission
standard. EPA requests comments and
information on whether these situations
do exist, their causes, their significance
to public health, whether emission
standards are needed, and what
emission levels would be appropriate.
B. Phosphate Industry
The phosphate industry processes
phosphate rock to produce fertilizers,
detergents, animal feeds and other
products. The production of fertilizer
uses approximately fio percent of the
phosphate rock mined in the United
States. Diammonium phosphate and
triple superphosphate are the phosphate
fertilizers produced in the largest
quantities. Phosphite deposits contain
large quantities of natural radioactivity,
principally uranium-238 and members of
its decay series. Uranium concentrations
in phosphate deposits range from 10 to
100 times the concentration of uranium
in other natural rocks and soils.
The processing of phosphate rock in
dryers, grinders, and fertilizer plants
j-esults in the release of radionuclides
into the air. As with coal-fired boilers,
control techniques that remove
particulars will also control
radionuclide emissions and risks.
Particulate emissions from the process
exhausts of these plants are already
well controlled, and the doses to
individuals and populations from the
radionuclides contained in the
particulates are less than 15 mrem/y to
any organ,
Particulate emissions From new or
modified phosphate rock dryer and
grinder facilities are already regulated
by NSPS under Section 111 "of the Act
[47 FR16562, April 16,1982). To meet
these standards, high-energy scrubbers
of high-energy ESPs are usually installed
on dryers, and fabric filters are installed
on grinders, Particulate emissions from
existing dryers and grinders are
regulated under SIPs, About 20 percent
ot the existing dryers already have
controls equivalent to NSPS: the
remaining dryers either employ low-
energy or medium-energy scrubbers,
About 75 percent of the existing grinders
already have controls equivalent to
NSPS: the remaining grinders use the
equivalent of medium-energy scrubbers.
To retrofit all existing phosphate rock
dryers with best available technology
would require a capital expenditure of
$44 million and an. increase of S3 million
in annual operating costs. This would
reduce the maximum individual bone
dose from is mrem/y to 3 znrem/y and
avoid l health effect in 50 years of
operations, To retrofit all existing
phosphate grinders with best available
technology would require & capital
expenditure of 54 million but would not
increase the annual operating cost. This
would reduce the maximum individual
bone dose from 1 mrem/y to 0-2 mrera/y
and avoid 1 health effect in 500 years of
operations.
Phosphate fertilizer plants use wet-
scrubber systems on their process
exhausts. These controls are needed to
comply with NSPS (40 CFR Part 60.
Subpam T through X) or SIPs for
fluoride emissions. About 75 percent of
the existing industry production
capacity is controlled by both primary
and secondary scrubbers. Scrubbers
used to control fluoride emissions are
also effective controls for particulate
emissions.
To retrofit all existing fertilizer plants
with secondary scrubbers on their
diammonium phosphate and triple
superphosphate process stacks would
require capital costs of $14 million and
would result in an increase of $1,5
million in annual operating costs. This
would reduce the maximum individual
bone dose from 2 mrem/y to 1 mrem/y
and would avoid 1 health effect in 500
years of operations.
In summary, EPA is not proposing
standards for phosphate rock dryers and
grinders or phosphate fertilizer plants.
because (1} the bone dose to individuals
represent a small hazard to health
compared to a similar dose to most
other organs, (2) the potential for
increased emissions is not present due
to the limited amount of radionuciides in
the phosphate rock, (3) other Clean Air
Act standards require controls that also
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Federal Register / Vol. 48, Mo, 67' / Wednesday, April 6, 1983 / Proposed Rules
15087
reduce radionuclide emissions, and (4)
the cost to further reduce radionuclide
emissions is unreasonably large
compared to the additional protection
achieved.
About 25 percent of the phosphate
rock used for fertiliser production is
treated in cakiners rather than dryers to
remove organic matter prior to
processing. Since eakSners operate at
significantly higher temperatures than
dryers, this may result in the ,
volatilization and release to air of
significant quantities of polonium-230,
similar to the emissions from elemental
phosphorus plants, Radionuclide
emission studies are being planned for
phosphate rock eaiciner plants.
However, no radionuclide emission data
are available for caleiners, and,
therefore, EPA is unable to determine at
this time that standards are needed for
these facilities, EPA requests comments
and information on these emissions,
their significance to public health,
whether emission standards are needed,
and what limits would be appropriate.
C Other Extraction Industries
Almost all industrial operations
involving removal and processing of
soils and rocks to recover valuable
commodities release some radionuclidea
into the air. EPA has carried out studies
of airborne radioactive emissions from
such mining, milling, and smelting
Operations.
The industries studied include iron,
copper, zinc, clay, limestone, fluorspar,
and bauxite. These are relatively large
industries and are, therefore, considered
to have the greatest potential for
emitting radioactive materials into the
air.
Although the analysis of data from
these stidies is not complete, the
information available to the Agency at
the present time shows that the
radiation doses to individuals and
populations from radionuclide emissions
from these types of facilities are small
and would not be reduced tt reasonable
cost Therefore, EPA is not proposing
standards for these parts of the
extraction industry.
D. Uranium Fuel Cycle tbcitities.
Uranium Mill Tailings, and
Management of High Level Waste
The Uranium Fuel Cycle (UFC)
consists of operations associatd with
production of electric power for public
wse by light'water-cooled reactors using
uranium fuel. It includes light-water-
cooled nuclear power plants and
facilities that mill the uranium ore,
enrich uranium, and fabricate and
reprocess uranium fuel EPA has
promulgated emission standards for
normal operations of the UFC under the
Atomic Energy Act (40 CFR Part 190),
These standards limit the annual dose
equivalent to body organs of nearby
individuals to 25 mrem/y [75 mrem/y for
the thyroid) and limit the emissions of
krypton-85, iodine-129, and other long*
half-life, alpha-emitting, transuranium
radionuelides. As a practical matter, the
EPA standards and their implementation
by the NRG require the use of best
available technology, which keeps doses
to individuals and populations to low
levels. The estimated individual risk
associated with 2S mrem/y to all organs
*&»r a lifetime is about i in 2000,
Uranium mill tailings remain after
uranium ore is processed to remove th*
uranium. Altogether, there are many
thousands of acres of these tailings at
both inactive and active uranium mill
sites, mosely in the Southwest. Large
amounts of radou-222 are emitted to air
from the piles due to the radium-226
remaining in the tailings after the
uranium is removed. Congress
addressed this problem through the
Uranium Mill Tailings Radiation Control
Act of 1S78 (Pub, L 95-604}, Under this
authority, EPA has active programs to
promulgate standards requiring remedial
actions that will, among other
objectives, prevent these tailings from
being moved and prevent radon from
escaping after the piles become inactivs.
Standards have been promulgated for
inactive mill sites and will soon be
proposed for active mill sites.
The highly radioactive liquid or solid
wastes from reprocessing spent nuclear
fuel, or the spent fuel elements
themselves if they are disposed of
without reprocessing, are called "high
level wastes". Over the last several
years, the Federal government has
intensified its program to develop and
demonstrate a permanent disposal
method for high level waste. As part of
this effort, EPA has proposed standards
to limit radiation exposure of members
of the public from management of this
waste prior to disposal (47 FR 58196.
December 29,1982). These proposed
standards would limit the annual dose
equivalent to any member of the public
to 25 mrem/y to the whole body, 75
mrem/y to tEe thyroid, or 25 inrem/y to
any other organ. Waste managment
operations are also to bt conducted so
«a to reduce exposures below these
levels to the extent that this is
reasonably achievable-
EPA is not proposing additional
radionuclide standards for UFC
facilities, uranium mill tailings, and high
level wastes because the Agency
believes (hat EPA standards established
{or to be established) under other
applicable authorities will protect public
health with an ample margin of safety in
the same way as an emission standard
established under Section 112 of the Act
£, Low Energy Accelerators
Accelerators, which impart energy to
charged particles sach as electrons,
alpha particles, and protons, are used
for a wide Variety of applications,
including radiography, activation
analysis, food sterilization and
preservation, radiation therapy, aad
research* There are over 1.200
accelerators in use in the United States,
not including accelerators owned by
DOE. This number has been growing at
a rate of approximately $5 machines per
year.
Accelerators other than those owmed
by the DOE operate at low energy levels
(i-fr. less energy is imparted to the
particles}. These machines emit very
small quantities of radionuelides
(specifically, carbon~l.lt carbon-14,
nitrogen-13, oxygen-JS, and argon-41)
because they operate at relatively low
energies. In addition, those accelerators
using tritium targets may emit a small
quantity of tritium, typically less than 1
Ci/y, The quantity of radionuelides
produced is so small that the doses and
health risks associated with those
emissions are extremely low, generally
several orders of magnitude less than
other sources discussed in the proposed
rule. Further, there is no practical way to
reduce them. EPA is not proposing
standards for accelerators because of
the low doses, less than 1 microrem/y to
nearby individuals, and because there is
no potential for the doses from existing
or new facilities to exceed this level
significantly.
F. Request for Comments
EPA requests comments on its
proposed decisions not to issue
standards for radionuclide emissions
from the categories of sources just
described. These decisions will be
reconsidered if additional information
becomes available indicating that doses
and risks are significantly greater, costs
are significantly lo\«er. or controls are
more available than those on which EPA
based its decisions.
If the Administrator decides not to
issue standards for particular source
categories, such decisions are likely to
be accompanied by determinations that
these decisions are of nationwide scope
and effect under the terms of section
307(b] of the Act.
VIII. Miscellaneous
A. Docket
The Docket is an organized and
complete file of all information
-------
15088
Federal Register / Vol. 48, No. 67 / Wednesday, April 6, 1983 / Proposed Rules
considered by EPA in the development
of these proposed standards, The
Docket allows interested persons to
identify and locate documents so that
they can effectively participate in the
ruleffieiking process. It also serves as the
record for judicial review.
A transcript of tht hearing and al!
written statements will be placed in the
Docket and will be available for
inspection and copying during normal
working hours.
B, Executive Order 12291
Under Executive Order 12291, issued
February 17,1981, EPA must judge
whether a rule is a "major rule" and,
therefore, subject to the requirement
that a Regulatory Impact Analysis be
prepared. EPA has detemined that this
rule is not a major rule as that term is
defined in Section l(b) of the Executive
Order.
EPA concluded that the rule is not
major under the criteria of section l(b)
because the annual effect of the rule Qfi
the economy will be less than S100
million. It will not cause a major
increase in costs or prices for any sector
of She economy or for any geographic-
region. Also, it will not result in any
significant adverse effects on
competition, employment investment,
productivity, innovation, or on the
ability of United States enterprises to
compete with foreign enterprises in
domestic or foreign markets.
This proposed rule was submitted to
the Office of Management and Budget
[OMB] prior to publication, as required
by the Executive Order.
List of Subjects in 40 CFR Part fl
Air pollution control. Asbestos.
Beryllium, Hazardous materials,
* Mercury, Vinyl chloride, Radiotiuelides.
C Paperwork Reduction Act
The Paperwork Redaction Act of 1980
(Pub. L. 96-511) (PRA) requires that the
Office of. Management and Budget
review reporting and reeordkeeping
requirements that constitute
"information collection" as defined.
Assuming, without deciding, that some
or all of the proposed reporting and
reeordkeeping requirements constitute
information collection within the
meaning of the PRA, the PRA requires
the Office of Management and Budget to
review information coliection activities
tq determine whether they are
"necessary for the proper performance
of the functions of the Agency" (section
3508).
This proposal, if promulgated, would
impose reporting and recordkeeping
requirements for one Federal agency
and on owners and operators of
elemental phosphorus plants and
underground uranium mines.
EPA requests comments on the
reasonableness of the Information
collection requirements and on the costs"
involved as compared to other means of
compliance determinations.
D. Regulatory Flexibility Analysis
Section 603 of the Regulatory
Flexibility Act, 5 U.S.C, 603. requires
EPA to prepare and make available for
comment an "initial regulatory
flexibility analysis" in connection with
an^ rulemaking for which there is a
statutory requirement that a general
notice of proposed rulemaking be
published'. The "initial regulatory
analysis" describes the effect of the
proposed rule on small business entities.
However, Section 60i(b) of the
Regulatory Flexibility Act provides that
Section 603 "shall not apply to any
proposed * * * rule if the head of the
Agency certifies that the rule will not, if
promulgated, have a significant
economic impact on a substantial
number of small entities."
EPA believes that virtually all small
businesses severed by this proposed
rule tre already meeting the proposed
standards. Therefore, this rule will have
little or no impact on small businesses.
For the preceding reasons, 1 certify
that this rule, if promulgated, will not
have significant economic impact on a
substantial number of small entities.
Dated: March 29,1993.
Lee Thomas,
Acting Administrator.
It is proposed to amend Part 61 of
chapter I of title 40 of the Code of
Federal Regulations as follows:
l. By adding to the table of sections
the following items:
Subpart K—National Emission Standards
(or Radlonuclido Emissions from
Department of Energy Facilities
Sec.
61,120 Designation of facilities.
61.131 Definitions.
61,122 Standard.
61.123 Emission monitoring and test
procedures.
61.124 Compliance and reporting,
Subpart L—National Emission Standard for
Radionuciide Emissions From Facilities
Licensed by the Nuclear ffequtatary
Commission and Federal Facilities Not
Covered by Subpart K
61,130 Applicability.
61,131 Definitions.
61,132 Standard.
Subpart M—National Emission Standard for
Radiormclide Emissions From Underground
Uranium Minos
61.140 Applicability.
61.141 Definitions.
.
61.142 Standaid.
61.143 Emission tests,
81,144- Reporting,
Subpart N^-National Emission Standard for
RaditsnucJide Emissions From Elemental
Phospnorous Plants
$1.150 Applicability.
61.151 Definitions,
61.132 Standard.
61453 Emission tests.
61.134 Test methods and procedures!
61,155 Monitoring of Operations.
* * * * *
Appendix B—Test Methods
* * * * *
Method Ml—Determination *f pok>niwn-21O
emissions from stationary sources.
Authority: See. 112 and 30l(a), Cltan Air
Act, as amended (42 U.S.C. 7412.760l(a)J.
2. By adding the following Subpart K:
Subpart K—National Emission
Standards for Radionucfide Emissions
From Department of Energy Facilities
§ 61,120 Designation of facilities.
The provisions gf this subpart apply to
radiation dose equivalent values received by
member? of the public as the result of
operations at facilities that are owned or
operated by the Department of Energy and
that emit radionuclMts to air.
§ 61121 Definitions.
(a) "Whole body" means all human
organs, organ systems, and tissues
exclusive of the integumentary system
(skinj and cornea.
(b) "Organ" means any human organ
or tissue exclusive of the integumentary
system (skin) and the cornea.
[c) "Radiontidide" means any nuclide
that emits radiation.
(dj "Dose equivalent" means the
product of absorbed dose and
appropriate factors to account for
differences in biological effectiveness
due to the quality of radiation and its
distribution in the body. The anit of the
dose equivalant is the rent.
$61.121 Standard.
Emissions of radionuclides to air from
operations of Department of Energy
facilities shall not exceed those amounts
that cause a dose equivalent rate of 10
mreffi/y to whole body or 30 mrem/y to
any organ of any member of the public.
161.123 Emission monitoring and test
procedure*.
To determine compliance with the
standard, radionticlide emissions shall
be determined and dose equivalent
values to members of the public
calculated using EPA approved
sampling procedures, codes AIRDOSE-
EPA and R A BRISK, or other procedures
-------
Federal Register / Vol. 48, No. 67 / Wednesday. April 6. 1983 / Proposed Rules 15089
which EPA has determined to b«
suitable.
f $1,124 Compliance and reporting.'
DOE shall submit to EPA an annual
report which includes the results of
monitoring emissions from points
subject to this standard and dose
calculations for each site. The report
shall also describe the DOE program for
maintaining airborne radioiwclide
releases as low as practicable below the
standard, including a discussion of -
current controls, new control equipment
installed during the year, and a
discussion of new controls that are
under consideration.
3, By adding the following Subpart L:
Subpart L—National Emission
Standards for Radfortuelide Emissions
From facilities Licensed by the Nyelear
Regulatory Commission and Federal
Facilities Not Covered by Subpart 1C
S 61.130 Applicability.
The provisions of this subpart apply
to NRC-licensed facilities and to
facilities owned or operated by any
Federal agency other than the
Department of Energy, except that this
subpart does not apply to facilities
reflated tinder 40 CFR Part 190 or to
afty accelerator,
161.131 Definitions.
fa) "Agreement State" means and
State with which the Atomic Energy
Commission or the Nuclear Regulatory
Commission has entered into an
effective agreement under subsectia
274(b] of the Atomic Energy Act of 1354,
as amended.
fb) "Dose equivalent" means the
product of ebscrbed dose and
appropriate factors to account for
differences in biological effectiveness
-------
15090 Federal Register /Vol. 48, No. 67 /Wednesday. April 6. 1983 /Proposed Roles
(c) "Electric furnace" me&ns a unit in
which the phosphate rock is heated with
silica and coke to reduce the phosphate
to elemental phosphorus.
(d) "Curie" is a unit of radioactivity
equal to 37 billion nuclear
transformations (decays) per seeond-
§61.152 Standard.
Emissions of poIoniuni-210 to air from
sources subject to this subpart shall not
exceed i curie in a calendar year.
§ 51.153 emission tests.
(a) Unless a waiver of emission
testing is obtained under § 61,13, each
owner or operator required to comply
with § 61,152 shall test emissions from
his source within the following time
limits:
(1) Within SO days of the effective
date of this rule in the case of an
existing source or a new source that has
an initial startup date preceding the
effective date of this rule; or
[2) Within iO days of startup in the
case of a new source that did not have
an initial startup date preceding the
effective date of this rule.
(b) The Administrator shall be
notified at least 30 days prior to an
emission test so that EPA may, at its
option, observe the test.
(c) Each emission test shall consist of
three runs. The phosphate rock
processing rate during each test shall be
recorded. The averge of all three runs
shall apply in computing the emission
rate. For determining compliance with
the emission standard of § 61.152, the
annual polonium-210 emissions shall be
determined by multiplying the polonium-
210 emission rate in curies per metric
ion of phosphate rock processed by the
annual phosphate rock processing rate
in metric tons. In determining the annual
phosphate rock processing rate, the
values used for operating hours and
operating capacity shall be values that
will maximize the expected production
rate. If the owner or operator of a source
subject to this subpart changes his
operation in a way that could change his
emissions of poloniuni'21Q, he may
determine his compliance with the
requirements of this subpart On the basis
of calculations using data from previous
emission tests.
(d) All samples shall be analyzed, and
polonlum-210 emissions shall bs
determined within 30 days after the
source test. All determinations shall be
rtporlnd to the Administrator by a
registered letter dispatched before the
close of the next business day following
such determination.
(ej Records of emission test results
and other data needed to determine
(total emissions shall be retained at the
source and made available for
inspection by the Administrator for a
minimum of 2 years.
§61.154- Te$t methods and procedures.
(a) Each owner or operator of a source
required to test emissions under
§ 61.153, unless an eqivaient or alternate
method has been approved by the
Administrator, shall use the following
test methods;
l. Test Method I of Appendix A to
Part 60 shall be used to determine
sample and velocity traverses;
2. Test Method 2 of Appendix A to
PartlQ shall be used to determine
velocity and volumetric flow rate;
3. Test Method 5 of Appendix A to
Part 60 shall be used to collect
particulate matter containing the
polonium-210;
4. Test Method 111 of Appendix B to
this part shall be used to determine the
polonium-210 emissions.
§ 61.155 Monitoring of operations,
(a) The owner or operator of any
source subject to this subpart using a
wet scrubbing emission control device
shall install calibrate, maintain, and
operate a monitoring device for the
continuous measurement of the pressure
loss of the gas stream through the
scrubber. The monitoring device must be
certified by the manufacturer to be
accurate within ± 250 pascals {z 1 inch
of water], Records of these
measurements shall be maintained at
the source and made available for
inspection by the Administrator for a
minimum of two years,
(b) For the purpose of conducting an
emission test under 161,133. the owner
or operator of any source subject to the
provisions of this subpart shall install,
calibrate, maintain, and operate a
device for measuring the phosphate rock
feed to any affected nodulizing kiln. The
measuring device used must be accurate
to within ± 5 percent of the mass rate
over its operating range.
Appendix B—(Amended!
8, By adding the following test method
of Appendix B:
Method Hi—Determinniion of Polanium-2io
Emissions From Stationary Sources
Performance of this method should
not be attempted by persons unfamiliar
with the use of equipment for measuring
radioactive disintegration rates.
1.0 Applicability and Principle
1.1 Applicability. This method is
applicable to the determination of
polonium-210 emissions in participate
samples collected in stack gases.
1.2 Principle. A particulate sample is
collected from stack gases as described
in Method 5 of Appendix A to 40 CFR
Part 60. The polonium-210 in the sample
is put in solution, deposited on a metal
disc and, the radioactive disintegration
rate measured. Polonium in acid solution
spontaneously deposits on surfaces of
metals which are more electropositive
than polonium. This, principle-is
routinely used in the radiochemical
analyses of poloniu*a-21fl [reference 1).
2,0 Apparatus
2,1 Alpha-counter photomuttiplier.
tube, (5 cm], with associated electronics
to record pulses.
2,2 Constant temperature' bath at
85°C,
2,3 Polished aiekel discs. 3.8 cm
diameter, 0,6 mm thick.
2.4 Silver activated zinc sulflde
screeft.
2.5 Beakers, 400 ml, 150 ml.
2,6 Hot plate, electric.
2.7 Fume hood.
2,8 Teflon beakers, 130 ml.
Teflon is a registered trademark of
DuPoat Co,
3.0 Jteageats
3.1 Analysis.
3.1.1 Ascorbic acid, reagent grade:
3.1.2 Distilled water.
3,1,3 Hydrochloric acid 12M,
concentrated reagent grade.
3.1.4 Hydrofluoric acid 2SM, reagent
grade. y.
3.1.5- Nitric acid 16Af, concentrated
reagent grade.
3.1.6 Perchloric acid 12A£ 72 percent
reagent grade.
3-1." Sodium hydroxide ISM
Dissolve 720 g of sodium hydroxide
pellets in distilled water and dilute to 1
liter.
3.1,8. Trichloroethylene.
3-2. Standard solution. Prepare
calibrated solution of polonium-210 from
supplier of this radionuclide. Known
aliquots are to be used to establish
efficiency of deposition.
4.0 Procedure
41 Sample Preparation,
4.1.1 Place filter collected by EPA
Method 5 Part 60 in Teflon beaker, add
30 nil hydrofluoric acid and evaporate to
dryness on hot plate in hood.
4.1.2 Repeat step 4,1.1 until glass
fiber filter has been digested.
4.1,3 Add 100 ml 16M nitric acid to
residue in Teflon beaker and evaporate
to dryncss. Do not overheat.
4,1.4 Add 50 ml 16M nitric acid to
residue from step 4.1.3 and heat to 80*C.
4,1.5 Decant acid solution into glass
beaker and add 10 ml 1ZV perchloric
acid.
44,6 Heat acid mixture to perchloric
acid fumes.
-------
Federal Register / Vol. 48. No. 67 / Wednesday, April 6, 1983 / Proposed Rules 15031
4.1.7 Adjust volume to 60 ml with
distilled wafer and neutralize with JSAf
sodium hydroxide,
4.1.8 Dilute to 100 ml with distilled
water and adjust solution to Q.5M in HCl
by adding 4 ml 12A/hydrochloric acid.
4.2 Soaipfo Analysis. Analyze the
solution for polonium-210 using any
published method which involves the
spontaneous electrodeposition of
polonJwm-210. including the method
described below:
4.2.1 Add 200 ml of ascorbic acid
and heat solution to 85°C in constant
temperature bath. 4
4,2.2 Melt a thin coating of
polyethylene on the unpolished side of
disc to prevent deposition. Adhesion of
the polyethylene to the disc is enhanced
by sanding the nickel surface with
garnet paper,
4-2.3 Clean polished side with .
trichloroethylene, hydrochloric acid, and
distilled water.
4,2.4 Suspended nickel disc in the
solution using glass or plastic hook.
4.2.5 Maintain disc in solution for 3
hours while stirring the solution,
4,2.8 Remove nickel disc, rinse with
distilled water and dry at room
temperature,
4.3 Measurement of Po/onium-210.
4.34 Position deposition side of
nickel disc adjacent to zinc sulfide
screen on photo/multiplier tube and
count pulses.
4.3,2 Establish background count
rate by measuring counts over clean
nickel discs.
4.3,3 Determine procedure efficiency
fay adding calibrated aliquots of
polonium-210 to acid solution with clean
filter and following procedure through
radioassay step,
4.3.4 Determine counter efficiency by
carefully evaporating known aliquots of
poloniuin-210 on nickel disc and
measuring count rate, comparing count
rate to known disintegration rate as
fraction,
5.0 Calculations
5.1 Calculate the curies of poloniam-
210 In the sample using the following
equation;
CHS.
A - •
A=C«ries of polonium-210 in sample.
CT"total sample counts for counting
period.
CM=background counts for counting
period,
Ej,=procedure efficiency.
E(;=(;cHinting efficiency.
T=counting time in minutes.
D=deeay correction.
5,1.1 Decay Correction
I*
T=tlme in dsys from midpoint of
collection time to the counting time.
t)i=radiological half life of polonium-
210,138-4 days.
5~2 Procedure for Calculating
Emissions.
Calculate the poloni«m-2lQ emission
per metric ton of rock processed using
the following equation:
E _ _
V,U
E= Curies of polonium-210 per metric
ton of rock processed,
A=Curies of polonium-210 in sample
from 5.1.
Qjt=Volumetric flow rate of effluent
stream in m3/h.
V,=Total volume of air sampled in nr',
M=Roek processing ratg during
sampling in metric tons/far,
fi.0 References
1. Blanchard, Richard L- Rapid
Determination of Lead-210 and
Polonium-210 in Environmental Samples
by Deposition on Nickel. Anal, Chera,.
38.189 (1966).
IFR Doc. W-ST-Ji Filed +-VS£ &« en)
BtLUKC CODE 65SO-W-M
-------
APPENDIX P
List of Subcommittee Meetings, Briefings and Public Presentations
The Subcommittee held four meetings in Washington, D.C., three of them public,
The non-public neeting consisted of a writing session of Subcommittee members at
which no EPA staff attended with the exception of the Director of the Science
Advisory Board. Agendas for the three public meetings, which identify EPA staff
briefings and public presentations, are included lit this appendix* In addition,
transcripts of these public meetings are on file at the Science Advisory Board
offices.
-------
Room 1112
crystal Mall #2
1921 Jefferson Davis Hwy,
Arlington, Virginia
tJ.S* Environmental Protection Agency
Science Advisory Board
Subcommittee on Risk assessment for RacJionuclides
Open Meeting--January 16, 1984
9; 30 a.m.
9s45
10:00
10; 30
i
11:15
11:30
Opening Remarks
12:30 p.m.
Is30
2;15
3:00
3;15
Dr. McClellan
Dr. Yosie
Introduction of the Subcommittee
Charge to the Subcommittee
Risk Assessment and Risk
Management in the Office
of Radiation Programs
Mr« Sjoblom
Dr. Yosie
Mr. Sjoblom
Break
Radionuclides Background Briefings
1. A Computerised Methodology for Mr. Nelson
Estimating Environmental Concentra-
tions and Dose to Man from Airborne
Releases of Radionuc^?i<3es {AXRDQS
Model)
Lunch
, ,.»• t . f •**• . ^~ ._
Background Briefings, continued
2- Life Table Methodology for Bval- Dr. Eunger
uating Radiation Risks
3* Basis for EPA Radiation Risk
Assessments
Break
Committee Discussion and Development
of Plans for Future Activities
Dr. Ellett
4:00
Adjourn
-------
Room 1112 Crystal Mail *
1921 Jefferson Davis Hwy
Crystal City, Virginia
U. S. Environmental Protection Agency
Science Advisory Board
Subcommittee on Risk Assessment for Radiontielides
February 21-22, 1984--0pen Meeting
Tuesday^ February 21
9sQQ a.m. Opening Remarks
9;15
9:45
10:15
11:00
3. It 15
12:00
IsOO
2sOO
2i30
3:00
3slS
5:00
6:00
Recapitulation of the ORD
Risk Issues and Process
{From the Previous Meeting)
Update on Transport/Modeling
Briefing From the Previous
Meeting -- Questions from
the Subcommittee on the
Transport Modeling
(AIRDOS-EPA)
Dose Models and Risk Assess-
ment Models and Codes
Break
Discussion of Dose and Risk
Models, continued
Dr. R» MeClellan
Dr. T. Yosie
Dr. W. Ellett
Dr. C* Nelson
Dr. B. Sullivan
EPA Estimates of Cancer Fatal
ities
EPA Estimates of Genetic
.Effects
Statements From the Public
Dr* W. Ellett
Dr. K. Nelson
Hf* D. Scroggin, Idaho
Mining Assoc-
Dr. L. Hamilton,
Dr. J. Harley and
Dr. N. Harley
Dr. I. White,
Break
Case Study Briefing
1, Y-12 Facility
Recess
Subcommittee Dinner
Mr
. Hardin
-------
25
9:00 a*m* Opening Remarks
. n
Dr. McClallan
Continued Dr. p. Magno '
2. Phosphorus
11:00 Break
11?15 Subcommittee Discussion and
Future Agenda
12;3° '
-------
1112 Crystal Mall §2
1921 Jefferson Davis
Highway
Arlington, Va.
U.S. Environmental Protection Agency
Science Advisory Board .'
Subcommittee on Risk Assessment for Radionuclides
March 22-23* 1983
Thursday, March 22
9:00 am Opening Remarks
9:15
Dr. R, McClellan
Dr. T* Yosie
12:00 pm
1:00
1:15
1:30
3:00
3:15
3:30
4:30
G;00-8;00
Friday, March 23
9i00 am
9:10
Subcommittee Discussion of Issues
TO Be Included in a Draft Report
and Development of Preliminary
Position Papers
Lunch
Follow-Up on ¥-12 Case Study
Briefing
Supplementary Comments and
Materials on Cancer Risk
Estimates *
Application of Risk Assessment
Decision-Making
Break
Statements From the Public
Subcommittee .Discussion
Recess
Subcommittee Dinner
Opening Remarks
Dr. C. Nelson
Dr. W. Sllett
Mr. R. Guimond
Dr. H. Whipple
Utility Air
Regulatory Group
Or, R. McClellan
Subcommittee Discussion of Issues
To Be Included in a Draft Report
and Development of Preliminary
Position Papers
12:00
Adjourn
-------
Appendix E
References
1. Risk Assessment in theJFederal Government; Managing theProcess, Committee
on the Institutional Means for Assessment of lisks to Public Health, National
Academy of Sciences/National Research Council, 1983.
2. William D. Ruckelshaus, "Science, Risk and Public Policy," Speech Delivered
Before the National Academy of Sciences, June 22, 1983.
3, —, . „—,_ "Managing Risk in a Free Society," Princeton Alumni Weekly,
March 7, 1984, pp. 18-23.
4. The Effects on Populations of Exposure to Low Levels ofIonizing Radiation!
i960, Committee on the Biological Effects of Ionizing Radiation (BEIR III),
National Academy of Sciences/National Research Council, (1980)*
5* D. I. Turner, Workbook of Atmoshperic Diffusion Estimates. U.S. Department of
Health, Education and Welfare, 1969. Publication NO. 995-AP-26.
6. S. R. Hanna, G, A. Briggs, and R. P. Hosker, Jr., Handbook on Atmospheric Diffusion.
U. S. Department of Energy, 1982. TIC-11223.
7. F. A. Gifford, "Estimating Ground~Level Concentration Patterns From Isolated
Air-Pollution Sources; A Brief Summary," Environmental Research v* 25 (1981),
pp. 126-138.
8. T. V. Crawford, Atmospheric Transport of Radionuclides. Report of the Working
Group on Atmospheric^ Digger sign, Deposition aad_Resuspensigru ., Proceed ings of the
Workshop onEvaluationof ModelsJUsed for theEnvironmental Assessment of Radioniielide
Releases, Gatllntmtg, TN., September 6-9, 1977. Oak Ridge National Laboratory Report
No. CONF-77Q901 (Oak Ridge, TN).
9, C. A. Little, and C. W. Miller, The Uncertainty Associated With Selected Environmental
Transport Models. Oak Ridge National Laboratory Report Ho. ORNL-5528 (Oak
Ridge, TN, 1979).
10. J, F. Fletcher, and W. L. Dotson, HERMES;A DigitalComputer Code for Estimating
Regional Radiological Effects From the Nuclear Power Industry. Battelle Northwest
Laboratory, Document No. HEDL-TME-71-168 (1979).
11. Calculaltion ofAnnual Doses to Man From Routine Releases ofReactor Effluent for the
Purpose of Evaluating Compliance with 10 CFR Part 50,Appendix t» Regulatory Guide,
1.109 (Revision I), U.S. Nuclear Regulatory Commission (1977).
12, R. Sullivan and C. Nelson, RADRISK/BE1R-III, Part II: Dometric Methods and Codes
Used to Assess Radiation Risk (January, 1984 Draft).
13. R. L. Dobson, J. Straume, J. S. Felton, and P» C. Rwan, "Mechanism of Radiation and
Chemical Oocyte Killing in Mice and Possible Implications for Genetic Risk Estimation
(Abstract)," Environmental Mutagen ?. 5 (1983), pp. 498-499.
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APPENDIX F: Comparison of AIRBOS-EPA Predictions With Those of Other Models
and Real Data: Explanation of Table 1 and Figures 1-7
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EXPLANATION OF FIGS. 1-7 AND TABLE 1
Several internationally-recognized models for assessment of the transfer of
radionuclides through terrestrial foodchalns were compared by Hoffman and colleagues* *>*
Comparisons were made of the steady-state concentrations of Cs-137, Sr-90 and 1-131
In milk, meat and vegetables, as predicted by the various models, per unit of
chronic deposition rate. The units are uCi/kg per uCi/M ^-day* Among the nodels
compared are AIRDQS-EPA, International Atonic Energy Agency (IAEA), Hational Radiological
Protection Board of the United Kingdom (NEPB), BIOPATH (Studsvik Energlteknik AB»
Sweden) and U.S. Nuclear Regulatory Conmisslon (NIC). For some radlonuelldes in
some foods, observed data compiled by UNSC1A1 were compared to model predictions.
All the above models were run to produce time-independent estimates of steady state
concentrations per unit deposition rate*
In this exercise, these models were compared to predictions by PATHWAY, a
dynamic nsodel developed to predict human ingestlon of fallout-produced radionuclides
in the vicinity of the Nevada Test Site during the I950fs.3 PATHWAY predicts
tlme-interated concentrations in foods per unit of acute deposition"(tiCi-days/kg
per uCl/M*). It can be shown that this quantity Is mathematically equivalent to
the quantities predicted by the above models. The utility of using PATHWAY for
comparison is that it Illustrates time-dependencies in the various foodchaln
processes, and it has been rather carefully tested against real observations.^
In Figs 1-7, the results of PATHWAY are plotted by the calendar date of fallout
deposition, and the values predicted by the other models or observed by UNSCEAR are
also shown. The significant time-dependencies shown by the PATHWAY results mainly
reflect dynamics in animal diets, harvest practices of feed crops, and plant growth
patterns.
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A major difference between PATHWAY and the other models Is found In the mass
interception of radionuclides by foliage. Whereas PATHWAY uses a value applicable
to large fallout particles (50-300 uM), the other models use a value applicable to
submieron particles and gases* The PATHWAY predictions nay be mutiplied by a factor
of five to adjust for this particular difference. This has been done in Table 1, for
comparison to AISDQS-EPA.
In Table I, PATHWAY predictions scaled to correspond to real data observations
[PATHWAY (P*Q/P)] are compared directly to AIRDGS-EPA predictions as a test of
the latter model's accuracy* In the case of Sr-90 in vegetables, PATHWAY did not
use a comparable category, so the UNSCEAR data were used as the basis of testing
AIRDOS-EPA. For Cs-137 and Sr-90 in milk, both UNSCEAR and scaled PATHWAY results
could by compared to the EPA model.
I* Hoffman, F.O,, V. Bergstrom, C. Gyllander and A. Wilkens. 1983. The transfer
of Co-60, Sr-90, 1-131, and Cs-137 through terrestrial foodchalns: A comparisons
of model predictions. STUDSVIK/NW-83/417, Studsvik Energiteknik AB, Sweden,
2, Hoffman, F.O., V. Bergstrom, C. Gyllander and A. Wilkens. A comparison of
predictions from internationally recognised assessment models for the transfer
of selected radlonuelides through terrestrial foodchalns. Nuclear Safety (In Press),
3. Kirchner, T.B., F,W. Whicker arid M.D. Otis, 1983. PATHWAY: A simulation model
of radionuclide transport through agricultural foodchains. pp. 959-968 In
Lauenroth, W.K., G.V. Skogerboe and M* Flug (eds»). Analysis of Ecological
systems: State-of-the Art in Ecological Modelling. Elsevier Sci- Publ. Co.,
Amsterdam.
4. Kirchner, T»B. and F,W. Whicker. Validation of PATHWAY: A simulation model of
the transport of radlonuclides through agroecosysteos. Ecological Modelling,
22 (1983/1984), pp. (21-44.) Elsevier Sci. Publ. Co., Amsterdam.
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FIGURE 1
TIME-INTEGRAL OF f-131 CONCENTRATION IN MILK
PER UNIT DEPOSITION! MODEL COMPARISONS
BIO PATH
NRC
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PER UNIT DEPOSITION'. MODEL COMPARISONS
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TIME-INTEGRAL OF Cs-13? CONCENTRATION IN NON-LEAFY
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TIME-INTEGRAL OF SR-90 CONCENTRATION IN NON-LEAFY
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APPENDIX G
RADIATION ADVISORY COMMITTEE
Preamble
The Administrator of the Environmental Protection Agency has aslced the
Science Advisory Board (SAB) to establish a standing committee on environmental
radiation. The formation of s«eh a committee was recommended by the SAB Subcommittee
on Risk Assessment for Radlonuelides as part of its review of the scientific
basis of SPA's proposed standards for airborne radionucltdes. The newly created
committee is expected to provide a continuing source of scientific advice to
EPA's Office of Radiation Programs (ORP) and other elements of the Agency as
they carry out their mandated activities.
OBJECTIVE: To review and evaluate the scientific basis and quality
of the Agency's scientific assessments, research and other
scientific activities related to environmental radiation.
CHARGE: To provide, 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 capabi-
lities can be maintained At a high level. Further, the
committee Is expected to review and comment on the.adequacy
of scientific Information aad analyses used in developing
risk assessments and other scientific documents the ORP
and other Agency offices may prepare as a basis for risk
management decisions on radiation matters.
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SCOPE OF ACTIVITIES; Areas of current and planned committee activity Include!
1} providing independent scientific review of scientific
analyses used to estimate the importance of radiation
on the environment and people for EPA's rule making and
guidance development activities; 2) providing peer and
scientific review and advice to the Agency on the
development and maintenance of the state-of-the-art in the
various scientific areas needed to discharge its responsibilities
Including sources of radiation exposures and radioactivity*
movement of radionuelldes through the environment, estimation
of the dose received by people from both internally deposited
and external radiation sources and estimation of the health
and environmental risks of radiation exposure; and 3) identifying
priority monitoring and other scientific information needs
to support the Agency's regulatory activities for radiation*
PROCEDURE: The committee will meet at least twice annually, or more
frequently if necessary to carry out its assigned responsi"
bllities. It will hold public meetings to advise the Agency
and solicit Information front the public- The Committee will
report to the Administrator through the Executive Committee
of the Science Advisory Board*
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