[Federal Register Volume 59, Number 246 (Friday, December 23, 1994)]
[Unknown Section]
[Page 0]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 94-31618]


[[Page Unknown]]

[Federal Register: December 23, 1994]


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Part III





Environmental Protection Agency





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Federal Radiation Protection Guidance for Exposure of the General 
Public; Notice
ENVIRONMENTAL PROTECTION AGENCY

[FRL-5126-7]
RIN 2060-AE61

 
Federal Radiation Protection Guidance for Exposure of the General 
Public

AGENCY: U.S. Environmental Protection Agency.

ACTION: Proposed recommendations, request for written comments, and 
notice of public hearings.

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SUMMARY: The Agency is proposing to make recommendations to the 
President for new guidance to Federal agencies on radiation protection 
which would have two effects: it would cause a five-fold reduction in 
the maximum allowable risk of cancer from any Federally regulated 
activity involving nuclear materials or other sources of radiation; and 
it would decrease the cost of Federal regulation of radiation by 
promoting uniform treatment of radiation by all Federal agencies, and 
reducing costly duplicative and conflicting requirements.
    The new guidance would replace those portions of previous 
recommendations that apply to protection of the general public, 
approved by Presidents Eisenhower and Kennedy in 1960 and 1961, 
respectively. New Federal guidance issued in 1987 replaced those 
portions of the 1960 and 1961 guidance that applied to protection of 
workers.
    These proposed recommendations are based on a review of existing 
guidance in light of current scientific understanding of the risks of 
exposure to ionizing radiation and of the experience of Federal 
agencies in its control. They include both qualitative guidance on 
radiation protection and numerical guides for limiting radiation doses 
to the general public. The most significant proposed changes are that: 
the Radiation Protection Guide (RPG) be expressed in terms of a single 
weighted sum of doses to organs, and the separate RPGs for individual 
organs deleted; the current RPGs limiting the average genetic dose to 
members of the U.S. population to 5 rems in 30 years and the annual 
whole body dose to 500 millirem dose equivalent be replaced by a single 
RPG of 1 millisievert (100 millirem) effective dose equivalent received 
by or committed in a single year to any individual from all sources 
combined; doses from individual sources normally be limited to a 
fraction of the RPG; and increased emphasis be given to the principle 
that all exposure should be maintained as low as reasonably achievable, 
within the RPG.
    The Agency invites written comments on these proposals and shall 
also hold a public hearing, as discussed below. All written and oral 
comments will be considered carefully in preparing our final 
recommendations to the President.

DATES: Written comments in response to this notice of proposed guidance 
must be received on or before February 21, 1995, to be ensured full 
consideration. A public hearing will be held in Washington, D.C., on 
February 22 and 23, 1995. Requests to participate should be received on 
or before January 23, 1995. The schedule, location, and procedures for 
this hearing will be published in the Federal Register shortly.

ADDRESSES: Written comments (in duplicate if possible) should be 
submitted to: Central Docket Section Section (6102), Attn.: Docket No. 
A-83-41, U.S. Environmental Protection Agency, Washington, DC 20460. 
Written comments, the public hearing record, and other documents 
related to this rulemaking will be filed under the above docket number 
in Room M1500 at Waterside Mall, U.S. Environmental Protection Agency, 
401 M Street, S.W., Washington, DC. The docket may be inspected between 
8:00 a.m. and 4:00 p.m. on weekdays. A reasonable fee may be charged 
for copying.
    Requests to participate in the public hearing should be submitted 
to Allan C. B. Richardson, Deputy Director for Federal Guidance, 
Criteria and Standards Division, Office of Radiation and Indoor Air 
(6602J), U.S. Environmental Protection Agency, Washington, D.C. 20460. 
Requests to participate in the public hearing should include an outline 
of the topics to be addressed, the amount of time requested, and the 
names of the participants. EPA may allow testimony to be given at the 
hearing without prior notice, subject to time constraints at the 
discretion of the hearing officer.

FOR FURTHER INFORMATION CONTACT: Allan Richardson at the above address 
(telephone (202) 233-9213; FAX (202) 233-9629) concerning these 
proposed recommendations or the public hearing.

SUPPLEMENTARY INFORMATION:

Introduction

    The Administrator of the Environmental Protection Agency (EPA) has 
the responsibility to ``...advise the President with respect to 
radiation matters, directly or indirectly affecting health, including 
guidance for all Federal agencies in the formulation of radiation 
standards and in the establishment and execution of programs of 
cooperation with States.'' This authority stems from Executive Order 
10831; the Atomic Energy Act of 1954, as amended; and Reorganization 
Plan No. 3 of 1970. Guidance to Federal agencies has historically 
consisted of both qualitative and quantitative recommendations 
expressed as ``Federal Radiation Protection Guidance.'' The guidance 
proposed here would replace those portions of existing Federal 
Radiation Protection Guidance, adopted in 1960 (25 FR 4402) and 1961 
(26 FR 9057), that apply to protection of the general public.
    The purpose of Federal guidance is to provide a common framework to 
help ensure that the regulation of exposure to ionizing radiation is 
carried out by Federal agencies in a consistent and adequately 
protective manner. Although the individual Federal agencies have 
determined, and will continue to determine, the details of specific 
regulations, it is intended that they adhere to these proposed 
recommendations as basic, minimum requirements. It should be 
recognized, however, that in some situations application of these 
recommendations may be superseded by specific statutory requirements.
    These proposed recommendations have been developed by EPA in 
cooperation with the Departments of Agriculture, Commerce, Defense, 
Energy, Health and Human Services, Housing and Urban Development, 
Interior, Justice, Labor, and Transportation; the National Aeronautics 
and Space Administration; and the Nuclear Regulatory Commission. In 
addition, the Conference of Radiation Control Program Directors of the 
States contributed to the development of this proposal. This 
cooperation was carried out through an extensive series of interagency 
meetings carried out between 1986 and 1992, and agency reviews 
conducted in 1993.

Previous Relevant Actions by the FRC and EPA

    On May 13, 1960, President Eisenhower approved the first 
recommendations of the former Federal Radiation Council (FRC) for 
guidance to Federal agencies on the protection of workers and the 
general public from radiation (25 FR 4402). This guidance was extended 
by further recommendations approved by President Kennedy on September 
26, 1961 (25 FR 9057).
    Following a lengthy review by Federal agencies of those portions of 
the 1960 and 1961 guidance that applied to occupational exposure the 
Administrator of EPA made new recommendations for protection of workers 
which were approved by President Reagan on January 27, 1987 (52 FR 
2822). Those recommendations motivated a number of the changes now 
proposed here for protection of the general public.
    During the period since the current guidance was issued, EPA, alone 
and in concert with other Federal agencies, has sponsored major reviews 
of the health risks from exposure to low level ionizing radiation by 
the Committee on the Biological Effects of Ionizing Radiation (BEIR), 
National Academy of Sciences--National Research Council. These reviews, 
which were published in 1972, 1980, 1988, and 1990, each incorporated 
new scientific information that had become available since the 
preceding review and contributed directly to the deliberations which 
have resulted in these proposed recommendations.

Scope of the Proposed Guidance

    These recommendations would apply to most exposure of the general 
public to sources of ionizing radiation that are created or influenced 
by human activities, the principal exceptions being exposure of 
workers, of patients for medical purposes in the practice of the 
healing arts, and of the general public from accidents. They would 
apply, for example, to exposure of members of the general public due 
to: (a) emissions of radioactive materials or radiation from 
industrial, defense-related, and scientific operations; (b) use of 
radiation and radionuclides in consumer products and medicine (except 
for beneficial exposure of patients); (c) mining and processing of ores 
that contain naturally-occurring radioactive materials; (d) disposal of 
wastes generated by any of the above operations; and (e) transportation 
of radioactive materials involved in any of the above operations.
    Specific examples include, but are not limited to: nuclear 
installations, including mines, mills, and processors of uranium and 
thorium, nuclear fuel fabrication plants, nuclear reactors (nuclear 
power plants, critical and subcritical facilities, and research 
reactors), spent fuel storage and processing facilities, and weapons 
production, testing, and storage facilities; x-ray generators and 
radioactive sources; irradiation installations, such as particle 
accelerators and large irradiators for teletherapy, radiosterilization, 
and commercial product irradiation; inspection devices in airports; 
consumer products such as static electricity elimination devices, ion 
generating tubes, smoke detectors, and devices for producing light or 
an ionized atmosphere, such as for dials and laboratory measurements; 
and radioactive waste installations where radioactive wastes are 
handled, treated and conditioned, temporarily stored, or permanently 
disposed of.
    These proposed recommendations also address most terrestrial 
sources of exposure arising from human activities (these principally 
involve naturally-occurring radioactive materials), but not exposure 
due solely to background radiation or due to globally-dispersed effects 
of past activities and accidents. Excluded, for example, is 
consideration of variations in exposure which result from geographic 
location, as well as the small annual dose increment from past weapons 
tests and residual global contributions of past nuclear accidents, like 
that at Chernobyl in 1986, because it is not practicable to contemplate 
their control. For the purpose of these recommendations, ``background 
radiation'' includes radiation of cosmic and solar origin at the 
surface of the earth and radiation from naturally-occurring primordial 
and cosmogonic radionuclides found in the earth's crust or produced in 
the upper atmosphere by cosmic or solar radiation (including 
radioactivity normally ingested in food and water) that is not enhanced 
by human activities.
    By technological means, however, exposure to naturally-occurring 
radionuclides that might otherwise be considered sources of ``natural 
background'' may be enhanced. Technologically-enhanced exposure to 
natural radiation may be defined as exposure to natural sources of 
radiation which is increased by (or would not occur without) a human 
activity. Examples of such sources include radon and its progeny 
accumulated in buildings; wastes from mineral ores, including ores 
which are mined for uses or purposes other than for their radioactive 
isotopes; wastes and/or emissions from the burning of coal, oil, and 
natural gas; ion exchange resins and sludge from drinking water 
treatment; scale in oil- and gas-field piping; articles made from 
naturally-occurring radioactive materials, such as thorium in lantern 
mantles and in certain optical glasses, and uranium in certain ceramic 
glazes; and cosmic rays experienced during high altitude airplane 
flights.
    To the extent that exposure to such sources is controllable, they 
are addressed by these recommendations. However, the guidance does not 
recommend that all situations that could lead to increased exposure 
should necessarily be regulated. For example, there is no readily 
applicable means to reduce the small increase in radiation exposure 
while in flight. In addition, it would require many circumnavigations 
of the globe by airline on non-business matters to approach the 
recommended limit for dose to individuals. Similarly, we believe it is 
also not appropriate to regulate, for example, exploration of caves, 
mountain climbing, or residence in high altitude locations because of 
technologically-enhanced radiation. Decisions on what exposures are 
appropriate candidates for reduction through regulation have been and 
will continue to be based on legislative mandates and decisions by 
regulatory agencies.
    The largest single source of exposure of the general public is 
radon. Radon, a naturally-occurring radioactive gas, can accumulate in 
any structure that limits the free exchange of indoor and outdoor air. 
There are two general categories of sources that can generate 
significant amounts of radon within a building: radium-bearing soil or 
rocks naturally situated beneath or near the building and radium-
bearing materials used in construction or as fill beneath or near the 
building. Although exposure to radon from sources of the first kind may 
be enhanced or reduced by building location, design, or construction, 
these factors usually are not subject to direct Federal or State 
control. Exposure to the second category of sources (radium-bearing 
materials placed in or near a building) may be subject to direct 
regulatory control or alleviation through Federal or State programs.
    The numerical limits for individual dose proposed in this guidance 
do not include the contribution from indoor radon produced by either of 
the above categories of sources. EPA and the Centers for Disease 
Control have provided separate advice to the public for protection 
against exposure to indoor radon in A Citizen's Guide To Radon (EPA 
document 402-K92-001, May 1992, and subsequent editions) and EPA has 
published a series of other technical publications, pursuant to Pub. L. 
100-551 (Oct. 28, 1988, 102 Stat. 2755, amending the Toxic Substances 
Control Act, 15 U.S.C. Secs. 2601-2692). That advice is consistent with 
this proposed guidance, where applicable.
    Finally, these recommendations apply only to the management of 
normal operations of facilities and devices that may expose members of 
the public to radiation: that is, to controllable exposure to radiation 
and releases of radionuclides that may expose the general public. 
Normal operations include both those conditions that are expected to 
occur with certainty as well as those that may be predicted to occur 
with a reasonably large probability (e.g. anticipated operational 
occurrences at nuclear reactors), but not conditions with a very low 
probability of occurrence, such as the unintended re-entry of a 
satellite containing radioactive materials. These recommendations also 
do not apply to nuclear incidents, such as a major accident at a 
nuclear facility or the result of terrorist activity, or to exposure 
resulting from acts of war. Guidance for establishing radiological 
emergency response plans and for making radiation protection decisions 
during nuclear incidents has been provided by EPA in the Manual of 
Protective Action Guides and Protective Actions for Nuclear Incidents 
(EPA-520/1-75-001-A), pursuant to regulations issued by the Federal 
Emergency Management Agency (47 FR 10758, March 11, 1982). Additional 
guidance has been provided by the Food and Drug Administration on the 
prophylactic use of potassium iodide during radiological emergencies 
(47 FR 28158, June 29, 1982) and on the use of food and animal feed 
contaminated by an incident (47 FR 47073, October 22, 1982, and, 
jointly with the Department of Agriculture, 51 FR 23155, June 25, 
1986).
    Exposure to radiation as a medical patient, which may occur for 
diagnostic or for therapeutic purposes, is not covered by these 
recommendations. Recommendations of the Administrator of EPA and the 
Assistant Secretary for Health of the former Department of Health, 
Education, and Welfare concerning diagnostic use of radiation, approved 
by President Carter in 1978, are provided in Radiation Protection 
Guidance to Federal Agencies for Diagnostic X Rays (43 FR 4377). 
Additional specific recommendations and guidance on patient selection, 
evaluation of radiation exposure, quality assurance, and related topics 
have been published by the Department of Health and Human Services. 
However, decisions on the diagnostic or therapeutic use of radiation 
are the responsibility of individual patients and their physicians, and 
such decisions should be based on the benefits and risks of the use of 
radiation for the conditions specific to each patient. Since those 
decisions will involve considerations quite different from those 
addressed here--exposure of the general public to a variety of sources 
of general societal benefit--these recommendations do not apply to 
exposure of patients.
    These recommendations also do not apply to occupational exposure. 
Federal agencies should normally regulate or manage the exposure of 
workers in accordance with Radiation Protection Guidance to Federal 
Agencies for Occupational Exposure (52 FR 2822), approved by President 
Reagan in 1987.\1\ However, when workers can be exposed under 
conditions that also apply to members of the public (e.g., when the 
public has unlimited access to the work site), the source of such 
exposure should be controlled in conformance with these proposed 
recommendations for protection of the general public.
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    \1\In some situations the distinction between members of the 
public and workers will have to be carefully considered. A ;useful 
test for determining whether individuals should be considered 
workers or members of the public is whether or not their presence in 
the exposure situation in question is within the scope of their 
employment.
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The Need for Revision of the 1960 Guidance

    Since the current guidance was issued in 1960, knowledge of the 
effects of ionizing radiation on humans has increased substantially. 
The BEIR Committee of the National Academy of Sciences--National 
Research Council conducted major reviews of the scientific data on 
health risks of low levels of ionizing radiation in 1972 and again in 
1980.\2\ Portions of the information presented in the latter report 
were expanded in a 1988 publication on risks from exposure to alpha 
radiation.\3\ A comprehensive, major new review was completed in 
1990.\4\ Similar reviews have been published by the United Nations 
Scientific Committee on the Effects of Atomic Radiation in 1977, 1982, 
1986, and 1988.\5\ The most important results from these reviews, 
carried out over a period of more than two decades, are that, although 
estimates of the nature and general magnitude of the risks from 
radiation have not undergone fundamental revision, estimates of the 
principal risk, that of cancer, have increased roughly threefold and 
have become more certain.
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    \2\The Effects on Populations of Exposure to Low Levels of 
Ionizing Radiation, National Academy of Sciences, Washington, D.C., 
1972; The Effects on Populations of Exposure to Low Levels of 
Ionizing Radiation; 1980, National Academy Press, Washington, D.C., 
1980.
    \3\The Health Risks of Radon and Other Internally Deposited 
Alpha-Emitters, National Academy Press, Washington, D.C., 1988.
    \4\Health Effects of Exposure to Low Levels of Ionizing 
Radiation, National Academy Press, Washington, D.C., 1990.
    \5\Sources and Effects of Ionizing Radiation, United Nations, 
New York, 1977; Ionizing Radiation: Sources and Biological Effects, 
United Nations, New York, 1982; Genetic and Somatic Effects of 
Ionizing Radiation, United Nations, New York, 1986; Sources, 
Effects, and Risks of Ionizing Radiation, United Nations, New York, 
1988.
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    While our knowledge of the effects of radiation has become more 
definitive, the extent of our use of radiation has increased and our 
policies for regulating it have evolved. Prior to 1960, major uses of 
radiation were limited, and the primary concern of radiation protection 
was to ensure that doses to those few individuals that were affected 
did not exceed limits on dose from all sources combined. Since then, 
the numbers and types of man-made radiation sources have greatly 
increased, and, at the same time, public concern about environmental 
contaminants of all kinds has become an important influence in their 
management. Of particular significance is that the focus of the many 
environmental policies and laws that have emerged during the past two 
decades has been more on improving the levels of control of individual 
sources of contamination than on establishing a single acceptable level 
of risk to individuals from all sources combined. This shift of concern 
has led to the development of new concepts for determining the 
appropriate level of control of specific kinds of sources. For 
radiation sources, it has meant that attention has been focused on 
assessing the potential impact of each source, or class of similar 
sources, on populations and on the capabilities and costs of controls 
to reduce that impact. The result has been the promulgation of a series 
of regulatory requirements that are based on the specific 
characteristics of particular classes of sources of public exposure to 
radiation. These requirements invariably have been more restrictive 
than those required to meet the existing Federal guidance on dose to 
individuals from all sources combined.
    Concurrent with the improved understanding of the effects of 
ionizing radiation and the evolution of its regulation, international 
and national advisory groups have refined and revised their basic 
recommendations on radiation protection. In 1977, the International 
Commission on Radiological Protection (ICRP) published revised 
recommendations\6\ that have since been adopted, in whole or 
substantial part, in most developed countries. In 1990, the ICRP issued 
revised general recommendations\7\ that, for control of exposure of the 
general public, expanded on those issued in 1977, notably in the areas 
of policy for control of individual sources and the methodology for 
expressing doses and risks from radiation. National bodies have also 
contributed to the evolution of radiation protection practice. In the 
U.S., the most recent (1993) recommendations of the National Council on 
Radiation Protection and Measurements (NCRP)\8\ are, in most cases, 
consistent with those of the ICRP. The changes in the recommendations 
of these organizations reflect the improved understanding of effects on 
health of ionizing radiation, new methodologies for evaluating doses 
and risks from ionizing radiation, developing public policy on 
acceptable levels of risk, and refinements in the application of basic 
radiation protection principles to the regulation of individual sources 
of exposure of members of the public.
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    \6\Recommendations of the International Commission on 
Radiological Protection, ICRP Publication 26, Pergamon Press, 
Oxford, 1977.
    \7\1990 Recommendations of the International Commission on 
Radiological Protection, ICRP Publication 60, Pergamon Press, 
Oxford, 1991.
    \8\Limitation of Exposure to Ionizing Radiation, NCRP Report No. 
116, National Council on Radiation Protection and Measurements, 
Bethesda, MD, 1993.
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    All of the above developments--improved estimates of radiation 
risk, experience in regulating the constantly expanding complex of 
applications of ionizing radiation, and the evolution of improved basic 
concepts and methodology for radiation protection--have contributed to 
the need for this proposed revision of the 1960 guidance.

Effects of Radiation on Human Health

    Effects on human health of concern from exposure to low levels of 
ionizing radiation may be divided into three categories.\9\ The first 
of these encompasses all forms of cancer (including leukemias). Cancers 
associated with radiation are not distinguishable from those associated 
with other causes. Although radiogenic cancers are observed in humans 
over a range of higher doses,\10\ it is necessary to infer the risk of 
cancer at the exposure levels normally encountered by members of the 
public because there is insufficient information to draw direct 
conclusions based on observations of cancer at these levels.
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    \9\A fourth category of effects, designated ``non-stochastic,'' 
occurs at dose levels higher than those addressed by these 
recommendations. They are of importance for managing the response to 
nuclear accidents (see EPA-520/1-75-001-A, op. cit.).
    \10\We use the general term ``dose'' to mean the dose 
equivalent, effective dose equivalent, committed dose equivalent, or 
committed effective dose equivalent, with the precise meaning to be 
inferred from the text. When precision is important, we use the full 
term. In 1990 the International Commission on Radiological 
Protection adopted new terminology (and definitions) for these 
quantities: equivalent dose in place of dose equivalent, and 
effective dose in place of effective dose equivalent. Although these 
terms are simpler and are acceptable for use, we use the older, more 
explicit terms.
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    The second category encompasses hereditary effects (mutations) 
induced in the reproductive cells of exposed individuals and 
transmitted to their descendants. The severity of hereditary effects 
ranges from inconsequential to debilitating or fatal. Although such 
effects are observed in studies of animals at high doses, excess 
hereditary effects have not yet been confirmed in epidemiological 
studies of the descendants of exposed human populations.
    Both cancer and hereditary effects are postulated to be caused by 
``stochastic'' (i.e. random) direct or indirect interactions of 
ionizing radiation with the genetic materials in living cells. In view 
of the extensive, albeit incomplete, scientific evidence supporting 
this view, including much theoretical and experimental radiobiology, it 
is commonly assumed that at low levels of exposure the probability of 
incurring either cancer or most serious hereditary effects increases 
linearly with dose, without a threshold. The severity of such effects 
is not believed to be related to the amount of dose received. That is, 
it is the probability of occurrence of a cancer or an hereditary 
effect, not its severity once it has been induced, that is assumed to 
be dependent upon the size of the dose.
    The risks to health from exposure to low levels of ionizing 
radiation have been reviewed by the National Academy of Sciences, as 
noted earlier, in a series of reports published between 1972 and 1990. 
Regarding cancer, there continues to be divided opinion on how to 
interpolate between the absence of radiogenic cancers at zero dose and 
the observed effects of radiation (mostly at higher doses than those 
normally encountered) to estimate the most probable effects of the 
doses actually encountered by members of the public.\11\ A 
preponderance of scientists believe that the available data best 
support the use of a linear model for estimating the effect of such 
doses. Some scientists, however, believe that other models provide 
better estimates. These differences of opinion have not been totally 
resolved by studies of the effects of radiation in humans, the most 
important of which are those of the Hiroshima and Nagasaki atom bomb 
survivors. Over the last decade an extensive reevaluation of the doses 
and effects in these survivors has been carried out. With respect to 
cancer, this reevaluation has strengthened the evidence for use of the 
linear model at doses near background levels.
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    \11\The risk of interest is not that at or near zero dose, but 
that due to small increments of dose above the pre-existing 
background level. Background in the U.S. is typically about 3 mSv 
(300 mrem) effective dose equivalent in a year, or 0.2 Sv (20 rem) 
in a lifetime. Approximately two thirds of this dose is due to 
radon, and the balance comes from cosmic, terrestrial, and internal 
sources of exposure.
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    These studies have also resulted in increased estimates (roughly 
threefold between 1972 and 1990) of the most probable risk of cancer 
from environmental levels of radiation. Nonetheless, the estimated 
number of health effects induced by incremental doses of radiation 
comparable to natural background levels remains small enough, relative 
to the number that already occur from other causes, that in all 
likelihood it will never be possible to detect them in human 
epidemiological studies. This lack of detectability does not mean, 
however, that such effects on health do not occur. In the absence of 
reliable evidence to the contrary, the Agency believes that it is 
appropriate, for radiation protection purposes, to assume that at and 
just above the level of natural background the risk of cancer and most 
serious hereditary effects increases linearly with increasing dose, 
without a threshold. That is, we assume that any increase in exposure 
to ionizing radiation carries the potential for causing harm to health. 
This assumption has been employed in the development of this guidance, 
and is consistent with current as well as historical practice for 
radiation protection world-wide.
    The third category of health effects involves those exposed in 
utero. It has long been believed that the unborn are more sensitive 
than are adults to the induction of cancer by radiation. The unborn are 
also subject to various radiation-induced physical malformations.\12\ 
Recent studies, however, have drawn renewed attention to the apparently 
greater risk of severe mental retardation from exposure of the unborn. 
These studies indicate that the sensitivity of the fetus is greatest 
during the period from 8 weeks to 15 weeks after conception, and 
continues at a lower level during the period 16 to 25 weeks.\4\ The 
risk of less severe mental retardation--manifested as a lowered 
Intelligence Quotient--is similarly elevated during these periods. 
Although it is not clear to what extent the occurrence and degree of 
retardation are proportional to the dose (or whether there is a 
threshold dose for these effects), it is prudent to assume, for 
regulatory purposes, that there is a linear, non-threshold relationship 
between these effects and the dose delivered to the fetus during these 
periods.
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    \12\These include small head circumference (microcephaly), brain 
size (microencephaly), eye malformations, and intrauterine growth 
retardation.
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    For radiation protection purposes EPA assumes, using a linear, non-
threshold model, an estimated risk to an average member of the U.S. 
population of 5 x 10-2 fatal cancers per sievert\13\ 
(5 x 10-4 fatal cancers per rem) delivered at low dose rates.\14\ 
(That is, we estimate that if 100,000 people chosen at random from the 
U.S. population were each given a uniform dose of 1 mSv (0.1 rem) to 
the entire body at a low rate of exposure, five cases of fatal cancer, 
on average, would occur during their remaining lifetimes, in addition 
to the roughly 20,000 cases that normally would occur from other 
causes.) The risk of inducing severe hereditary effects in their 
offspring is estimated to be smaller than that for cancer, namely, on 
the order of 10-2 per sievert (10-4 effects per rem).\15\ The 
risk of severe mental retardation from doses to a fetus is estimated to 
be greater per unit dose than the risk of cancer in the general 
population--5 x 10-1 per sievert (5 x 10-3 per rem)\16\--but 
the period of susceptibility is very much shorter.
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    \13\The traditional special unit for dose equivalent has been 
the rem. The special unit sievert (Sv) in the International System 
of Units, adopted in 1979 by the General Conference on Weights and 
Measures, is now in general use throughout the world. The RPGs 
recommended here may be expressed in either of these units. One 
sievert is equal to 100 rem. The prefix ``milli'' (m) means one 
thousandth.
    \14\``Low dose rates'' here means dose rates on the order of or 
less than those from background radiation (see footnote 11). This 
value for the risk from such doses incorporates a dose rate 
effectiveness factor of two.
    \15\The risk of severe hereditary effects in the first two 
generations, for exposure of the reproductive part of the 
population, is estimated to be 5 x 10-3 per Sv (5 x 10-5 
per rem). For all generations the risk is estimated to be 
1.2 x 10-2 per Sv (1.2 x 10-4 per rem). For exposure of 
the entire population, which includes individuals past the age of 
normal child-bearing, each estimate is reduced to 40% of the cited 
value.
    \16\The risk for mental retardation during the 8th through 15th 
week [estimated to be 4 x 10-1 per Sv (4 x 10-3 per rem)] 
plus the risk during the 16th through 25th week [estimated to be 
10-1 per Sv (10-3 per rem)].
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    The National Academy of Sciences has judged the 90% confidence 
limits for their most recent estimates of the risk of cancer to be 
about a factor of three greater and a factor of two less than their 
estimate of the most probable value. They also observe that, at the low 
doses and dose rates of concern in this guidance, the possibility that 
there may be no risk cannot be ruled out, since epidemiological data 
cannot rigorously exclude the existence of a threshold. The numerical 
values of risks of genetic abnormalities and mental retardation are 
somewhat less well established. In spite of uncertainties in the data 
and its analysis, however, estimates of the risks from exposure to low 
levels of ionizing radiation are better characterized than those for 
virtually any other environmental carcinogen.

Basic Principles

    In recommending the 1960 Federal guidance, the Federal Radiation 
Council said: ``Fundamentally, setting basic radiation protection 
standards involves passing judgment on the extent of the possible 
health hazard society is willing to accept in order to realize the 
known benefits of radiation'' (25 FR 4402). The need to make this 
judgment led to three basic principles that have governed radiation 
protection for many decades in the United States and in most other 
countries. Although the precise formulation of these principles has 
evolved over the years, their intent has remained essentially 
unchanged.
    The first principle is that any activity involving the exposure of 
people to ionizing radiation should be sufficiently beneficial to 
society to warrant the exposure; i.e., a finding should be made that an 
activity causing exposure is ``justified.''
    The second is that, for justified activities, exposure of people 
should be ``as low as reasonably achievable.'' This principle commonly 
has been designated by the acronym ``ALARA'' in the United States, and 
is called ``optimization'' of radiation protection in international 
practice.
    The third is that, even for justified and optimized exposures, the 
maximum dose to any individual should be limited so as not to exceed an 
acceptable level of risk. This is referred to as ``limitation.''
    The objective of the first two principles is to minimize 
(consistent with benefits and costs) the estimated total harm (i.e. 
health detriment) in the entire population from each source of 
exposure; they do not, however, limit the way that harm is distributed 
among individuals. They are, in this sense, ``source-related'' 
radiation protection requirements. The purpose of the third principle, 
that of limitation of the maximum allowed dose, is to provide an upper 
bound on risk to individuals. This principle, which is an ``individual-
related'' requirement, may be carried out in two ways: first, through 
limitation of the potential dose from all sources of exposure combined, 
and second, through additional more specific limitations on the doses 
from individual sources.
    The following seven proposed recommendations directly express, 
expand upon, and implement these three basic principles in light of 
current improved knowledge of the risks of radiation and of the variety 
and extent of uses of radiation. In particular, they reflect lower 
upper limits on dose to individuals from all sources combined, they 
make explicit the need for further limitation of doses from individual 
(or classes of) sources of exposure that is more restrictive than that 
for all sources combined, and they introduce improved methods for 
assuring that all of the various components of risk associated with 
radiation exposure are accounted for in radiation protection 
requirements for limiting exposure of the public.

Recommendation 1

    There should be no exposure of the general public to ionizing 
radiation unless it is justified by the expectation of an overall 
benefit from the activity causing the exposure. Justified activities 
may be allowed, provided exposure of the general public is limited 
in accordance with these recommendations.

    The principle that activities causing exposure of the general 
public should produce a net societal benefit has long formed a 
cornerstone of radiation protection policy, even though the judgment of 
net benefit is not easily made. The 1960 Federal guidance states: 
``There should not be any man-made radiation exposure without the 
expectation of benefit resulting from such exposure* * *,'' and ``It is 
basic that exposure to radiation should result from a real 
determination of its necessity.''
    Other advisory bodies have used language which has essentially the 
same meaning. In its 1990 revision of international guidance, the ICRP 
said ``* * *no practice* * *should be adopted unless it produces 
sufficient benefit to the exposed individuals or society to offset the 
radiation detriment it causes.'' When it addressed this issue in 1975, 
the NCRP said, ``* * *all exposures should be kept to a practicable 
minimum; * * *this principle involves value judgments based upon 
perception of compensatory benefits commensurate with risks, preferably 
in the form of realistic numerical estimates of both benefits and risks 
from activities involving radiation and alternative means to the same 
benefits.''\17\
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    \17\Review of the Current State of Radiation Protection 
Philosophy, NCRP Report No. 43, National Council on Radiation 
Protection and Measurements, Bethesda, MD, 1975.
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    These recommendations would continue the requirement for 
justification in terms of an overall benefit. An obvious problem in 
making this judgment is the difficulty of assessing, in comparable 
terms, costs (including risks) and benefits. Given this situation, 
informed value judgments may be necessary, and, in fact, are usually 
all that is possible.
    The determination that a particular activity involving exposure of 
the general public is justified is often a complex process. Commonly, 
it is not made by those directly responsible for radiation protection 
decisions. For a few activities, like the x-ray examination of feet for 
shoe-fitting practiced many years ago, agreement that there is not a 
net benefit was easy to achieve. The decision was simplified in that 
example because the risks and benefits accrued to the same individuals. 
This is usually not the case. In extreme cases the determination can be 
far more complex. For a major industrial application of radiation, for 
example, the determination may involve not only the benefits and the 
costs (direct, health, and environmental) of construction, operation, 
waste disposal, accidents, and eventual decommissioning, but also the 
tradeoffs between the activity and the economic, societal, 
environmental, and resource implications of alternative means to 
achieve the same result.
    In any case, for a major activity the analysis should make a 
reasonable demonstration that the benefit associated with the proposed 
activity clearly outweighs the risks associated with the use of 
ionizing radiation, including those associated with normal operations, 
reasonably possible incorrect operation or management, and disposal of 
wastes over the life cycle of the activity. When the consequences can 
be significant, the analysis should include low probability events and 
exposure pathways.
    The process of balancing these factors may eventually involve 
congressional, executive, and judicial inputs. One vehicle for 
assisting such decision-making is the National Environmental Policy Act 
of 1969 which, in effect, requires Federal agencies to assess and 
consider the above factors for any major Federal action that could 
significantly affect the quality of the human environment. Others 
include the regulatory analysis process pursued by Federal agencies 
(Executive Order 12866; 58 FR 51735, October 4, 1993), and decision 
processes of public and professional bodies, such as public utility 
commissions and professional medical groups. However, in making these 
recommendations EPA does not propose to specify how or by whom 
justification should be determined, but simply that the detrimental 
effects of radiation, as well as other detrimental effects, should be 
considered along with the benefits in any situation where an initial 
decision is being made that involves significant exposure of the 
general public to radiation.

Recommendation 2

    A sustained effort should be made to ensure that doses to 
individuals and to populations are maintained as low as reasonably 
achievable.

The idea that exposure to radiation should be kept to a practical 
minimum became a basic requirement in radiation protection early in the 
century, shortly after the recognition that harm from radiation is not 
limited to the skin damage that occurs at relatively high doses. The 
concept was first applied to exposure of individual workers, primarily 
in medical and research applications, since early uses of radiation did 
not involve large populations. Later, after the commencement of nuclear 
weapons testing and introduction of the widespread use of nuclear 
power, it was applied to the exposure of populations--first to 
safeguard the genetic pool and, later, after the assumption that cancer 
induction is a stochastic process became accepted as a prudent premise, 
also to reduce the presumed incidence of cancer. The requirement is now 
taken to be the logical and necessary consequence of the assumption of 
a linear relationship between exposure to radiation and the risks of 
cancer and hereditary effects at the dose levels addressed by these 
recommendations.
    The phrase ``as low as reasonably achievable'' (ALARA) is used to 
designate a general principle that exposure to radiation should be 
controlled so as to achieve the lowest level reasonably attainable. The 
1960 FRC guidance applied the concept to keeping dose to the individual 
as low as practicable, and expressed it as a responsibility to be 
carried out by the user of radiation. In these proposed recommendations 
the ALARA principle is broadened to apply to collective doses in 
populations as well, and in this broader application serves as a 
principal basis for the implementation of ALARA through regulatory 
practice. This use of the ALARA principle is customarily designated 
``optimization'' of radiation protection. Optimization may be carried 
out through regulatory determinations for whole classes of similar 
sources, as in the establishment of standards for environmental 
releases from nuclear power facilities, or, more directly, in the 
determination of operating requirements for a specific facility. 
Depending on the nature of the source, optimization may involve use of 
simple or complex decision tools for balancing public health and 
economic concerns to determine the optimal level of control. The basic 
elements required for optimization are the values placed on avoiding 
the estimated health detriments and the direct costs of control, as a 
function of various levels of protection. In reaching a final 
optimization determination, however, a variety of other economic and 
societal factors may also have to be considered, such as the 
distribution of health detriment over populations and over time, and 
the technical feasibility and overall economic impact of controls. In 
rare cases, the optimization process could result in the need to make 
tradeoffs between larger doses to a few individuals (within the limits 
specified in Recommendations 3 and 4) and many small doses in large 
populations.
    At the dose levels involved in the comparison of alternatives for 
determining ALARA levels, linearity is assumed, and effects on public 
health may be estimated from the collective dose in populations. In 
cases where it is necessary to estimate the total public health 
detriment from long-lived radionuclides, collective dose will often 
have to be projected into the future, or in distant populations. 
Regulatory decisions on ALARA levels should take into account such 
projections when their contribution is both a significant part of the 
total collective dose from the activity under examination and its 
uncertainty is not large compared to the differences in collective dose 
among the alternatives being examined. In some cases, it may be 
appropriate to estimate effects on public health as a function of time 
or distance, and to take their distribution in time or distance into 
account in decisionmaking. However, it will never be appropriate to 
apply an arbitrary cutoff to such projections based solely on the level 
of dose to individuals, or on the distance from the source or in time; 
such cutoffs would have the effect of preempting the decision-making 
process before the magnitude and distribution of the avoidable impact 
on health has been estimated.
    In some situations, a decision to refrain from applying controls 
may be the appropriate outcome of an ALARA determination. Such a 
finding for an individual practice, or for a group of practices meeting 
specified requirements, may be used as one criterion for exemption from 
regulatory control. However, in addition to a finding that the total 
health detriment in populations is not large enough to justify control, 
it is also necessary to ensure that individual exposures are 
sufficiently small, in view of the stipulations of Recommendation 4, 
not to warrant regulation. Exemptions that satisfy each of these 
criteria would be consistent with these proposed recommendations.
    Although the ALARA principle is relevant to a wide variety of 
radiation protection activities, these tend to fall into two general 
categories. The first is that emphasized above, the establishment of 
regulatory levels of control over individual sources or categories of 
sources by Federal (or State) agencies. The second, and equally 
important, is making management decisions in day-to-day operations at 
facilities where ionizing radiation or radioactive materials are 
present. The selection of regulatory limits for facilities, as well as 
the day-to-day management of sources, in a manner consistent with the 
ALARA principle are discussed further in connection with Recommendation 
4.

Recommendation 3

    The preceding recommendations address the need for justification 
and optimization of activities that involve exposure of the general 
public. The third basic radiation principle, limitation of maximum dose 
to individuals, is addressed by the next two recommendations. 
Recommendation 3 limits the sum of doses to any individual from all 
radiation sources combined, through the Radiation Protection Guide 
(RPG) for the general public; and Recommendation 4 addresses limitation 
of doses from individual sources, through the establishment of source-
specific authorized limits.
    The RPGs established in 1960 and 1961 consist of separate limits on 
dose to the whole body and bone marrow (0.5 rem in a year, each), the 
thyroid and bone\18\ (1.5 rem in a year, each), and the gonads (5 rem 
over 30 years, average in the U.S. population). Those recommendations 
(except that for the gonads) were based on the concept of limiting the 
dose to the most critically exposed organ of the body.\19\ That is, it 
was assumed that if dose to the critical organ was limited to an 
acceptable level, then doses to other parts of the body would also be 
acceptably low. One consequence of this approach is that exposure of 
the body to external sources of radiation and exposure to internal 
radioactivity are addressed by separate limits, and therefore the risks 
from such exposures can be additive. Further, when several different 
organs are exposed to internal radiation simultaneously, only the part 
of the body receiving the highest dose relative to its RPG is decisive 
for limiting the dose. That is, the risks associated with exposure of 
other parts of the body are not considered in applying a dose limit 
based on the critical organ approach. The 1960 limit for dose to the 
gonads was based on an entirely different consideration, that of 
limiting the incremental rate of mutation in the entire genetic pool of 
the U.S. population. The incremental level of mutation deemed 
unacceptable was on the order of a few per cent.
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    \18\The guidance also included an approximately equivalent RPG 
for bone in terms of radium-226 in the adult skeleton (0.003 
micrograms).
    \19\This was an incomplete set for this scheme of protection, 
since many relevant parts of the body were not assigned RPGs. The 
1960 RPGs for workers, by contrast, did comprise a complete set, 
and, for the general public, the missing values for other parts of 
the body were generally taken as \1/10\ of the corresponding 
occupational values.
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    These recommendations would replace the system described above with 
the risk-weighted dose limitation system introduced by the ICRP in 
1977\6\. The ICRP system takes into account the individual contribution 
of each exposed part of the body to total risk. It does so by assigning 
to each organ or tissue of the body a weighting factor that is 
proportional to the risk per unit dose of inducing cancer or, for the 
reproductive organs, to the risk per unit dose of inducing hereditary 
effects in offspring. The risk limit is then expressed in terms of the 
sum of weighted dose equivalents to all parts of the body, a quantity 
called the ``effective dose equivalent'' (EDE).\20\ A limit in terms of 
the EDE therefore reflects both the distribution of doses among the 
various organs and tissues and their assumed relative sensitivities to 
cancer and hereditary effects. Further, the EDE does not differentiate 
exposures from external and internal sources; it includes both.
---------------------------------------------------------------------------

    \20\The weighting factors are normalized so that the risk 
associated with a given EDE is equal to that from a uniform dose of 
the same magnitude to the whole body.
---------------------------------------------------------------------------

    The effective dose equivalent is defined formally in footnote (b) 
to Recommendation 3 and proposed weighting factors are listed in Notes 
5 and 6, in the formal statement of proposed recommendations at the end 
of this notice. These factors reflect the organ-specific risks of 
lethal cancer, and, for the reproductive organs, the risk of serious 
hereditary effects in the first two generations of offspring. They are 
the same weighting factors as those adopted in Federal guidance on 
radiation protection for workers in 1987. Although our current best 
estimates for these effects on health would lead to somewhat different 
values, the differences are sufficiently small that new weighting 
factors are not proposed as part of these recommendations. The Agency 
has made this choice for several reasons. First, it should be noted 
that changes in the weighting factors, based on new estimates for 
mortality, would have no effect on the level of risk represented by a 
given dose to the whole body, since the sum of the weighting factors 
is, by definition, normalized to unity. (If these factors were adjusted 
to take into account non-lethal cancers or other factors such as age at 
incidence the risk level could change, but, for the same reason, this 
change would be small.) Thus, the general level of risk achieved would 
not be affected. Second, the ICRP has recently published revised 
weighting factors that, in addition to incorporating updated 
information on risks of mortality, also consider other factors such as 
morbidity, i.e., the risk of non-lethal cancer (but do this without 
changing the recommended dose limit).\7\ We are reviewing those 
weighting factors, as well as our own estimates of organ-specific risk 
factors. Finally, extensive new tabulations, for each of over 700 
radionuclides, of dose factors for various chemical forms and routes of 
exposure have recently been completed using the existing weighting 
factors.\21\ Regulations using these dose factors are being implemented 
by EPA, NRC, and DOE. Changing the weighting factors for many of these 
regulations will require formal rulemaking. EPA will keep these 
considerations under review, will continue to review the choice of 
weighting factors as new information becomes available, and will issue 
guidance on improved weighting factors from time to time, following 
review by and consultation with affected Federal agencies.
---------------------------------------------------------------------------

    \21\These are specified in Note 7 to the Recommendations.
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    Recommendation 3, which specifies the proposed new RPG for the 
general public, consists of three parts. We first set forth the text of 
the recommendation and some explanatory details, and then discuss the 
basis for the choice of the value of the RPG and other related matters. 
The first part of Recommendation 3 reads:

    The combined radiation doses incurred in any single year from 
all sources of exposure covered by these recommendations should not 
normally exceed a Radiation Protection Guide of 1 mSv (100 mrem) 
effective dose equivalent to an individual. The Radiation Protection 
Guide applies to the sum of the effective dose equivalent resulting 
from exposure to external sources of radiation during a year and the 
committed effective dose equivalent incurred from the intake of 
radionuclides during that year.

    This recommendation would replace the 1960 and 1961 RPGs for dose 
equivalent to the whole body and specified parts of the body by a 
single RPG of 1 mSv (100 mrem) effective dose equivalent in a year. In 
so doing, it would create a single limit for combined dose from 
external and internal radiation.
    Certain radionuclides, if inhaled or ingested, may remain in and 
continue to irradiate the body for many years. This proposed 
recommendation incorporates the use of ``committed'' dose into guidance 
for the general public (this concept was introduced into Federal 
radiation protection guidance for workers in 1987). It provides that 
Federal agencies should base control of annual intake of such 
radionuclides upon the future dose that may result over time (that is, 
the committed dose), not just the ``annual'' dose accrued during the 
first year following intake. This would assure that, in regulating 
annual intake of such materials by members of the public, account is 
taken of the additional risks committed from doses that will be 
delivered in future years. The standard period for which committed dose 
is calculated is proposed to be taken as 50 years, as in the Agency's 
previous recommendations for workers. Although there are a few 
radionuclides from which doses can accrue for longer periods, the risk 
associated with intake of such radionuclides will be conservatively 
estimated, compared to the risk from a comparable external dose, 
because of the combined effect of the distribution over time of 
committed dose and the latency period for expression of cancer.
    The proposed RPG is expressed in terms of both the new special SI 
unit ``sievert'' and the historically-used special unit ``rem.'' It is 
not the intent of these recommendations to express a preference for 
either system of units, but merely to recognize the existence and 
acceptability of both. Federal agencies would be free to use either 
unit under these recommendations, but should specify conversion factors 
between the two systems in new regulations.
    The second part of Recommendation 3 reads:

    The Radiation Protection Guide may not be reasonably achievable 
in some unusual situations. It may be exceeded temporarily in 
situations that are not anticipated to recur chronically and when 
Recommendations 1 and 2 are satisfied, provided that the radiation 
dose incurred in any year does not exceed 5 mSv (500 mrem) effective 
dose equivalent.

    It is not anticipated that this provision would be used frequently. 
In the past, doses to members of the public at or near such levels have 
been uncommon, and the Agency expects this to continue to be true. We 
have identified two examples of situations in which such doses are 
known to occur now, and might reasonably be permitted to exceed the 
RPG. The first is through the incidental exposure of a family member, 
household member, or friend to a patient being treated (or diagnosed) 
using radioactive materials, for certain medical procedures (primarily 
in the treatment of thyroid cancer using\131\I). The second involves 
the exposure, in some unusual cases, of individuals living near 
radioactive contamination that has not yet been cleaned up. This almost 
invariably involves naturally-occurring materials, often from mining or 
milling operations. In situations where temporary relocation is not an 
acceptable alternative it may not be practical to complete such cleanup 
without exposing a few members of the public to doses exceeding 1 mSv 
(100 mrem) in a year. This provision is not intended for use as a limit 
in dealing with short-term emergency situations arising from nuclear 
accidents; these are governed by the Protective Action Guides for 
nuclear incidents (EPA-520/1-75-001-A).
    The third part of Recommendation 3 reads:

    Continued exposure of an individual over substantial portions of 
a lifetime at or near the level of the Radiation Protection Guide 
should be avoided. This will normally be achieved through 
conformance of individual sources to Recommendations 2 and 4.

    In recommending an RPG of 1 mSv (100 mrem) in a single year, it has 
been necessary to balance the practical regulatory need for an RPG 
expressed in terms of annual dose against the public health objective 
of adequately limiting lifetime risk. We anticipate that satisfying the 
criteria specified in Recommendations 2 and 4 will almost invariably 
achieve this objective. However, in the unlikely event that 
circumstances were such that continued exposure at or near the RPG over 
substantial portions of a lifetime could occur, this portion of 
Recommendation 3 explicitly expresses the criterion that chronic 
exposure at such levels should be avoided.

Basis for the Radiation Protection Guide

    In the latter part of the twentieth century, society has become 
increasingly unwilling to accept risks imposed by activities that 
produce environmental pollutants. Many of the benefits of 
industrialized society, however, are brought about by activities that 
carry with them some unavoidable elements of risk. This is especially 
the case for so-called ``non-threshold'' pollutants like radiation, for 
which it is assumed that there are no risk-free levels. The risk to an 
individual from exposure to ionizing radiation, as discussed above, is 
assumed to depend linearly upon the radiation dose, without a 
threshold. Under current guidance the average member of the public now 
receives, from all the sources to which that guidance has consistently 
been applied, only a very small dose--less than 0.01 mSv (1 mrem) in a 
year.\22\ The average risk of fatal cancer incurred from such an 
exposure is estimated to be somewhat less than 5 in ten million.
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    \22\During the period 1960 to the present, the current RPG has 
not consistently been applied to exposure due to natural sources. 
The primary examples are building materials and radon in domestic 
groundwater supplies; these contribute additional average effective 
dose equivalents to the U.S. population of 0.035 mSv (3.5 mrem) and 
0.01-0.06 mSv (1-6 mrem), per year, respectively. Tobacco smoke 
contributes a further, at present incompletely characterized, dose. 
(These estimates are derived from Ionizing Radiation Exposure of the 
Population of the United States, National Council on Radiation 
Protection and Measurements Report 93, Bethesda, MD (1993).)
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    The cumulative risk to society associated with the variety of 
current uses of radiation is now governed by the dual requirements that 
each use be justified and that its effect on public exposure minimized 
by optimizing radiation protection. These requirements would be 
continued and strengthened under proposed Recommendations 1 and 2. 
Typically, this would result in a distribution of annual doses from 
each source of radiation exposure ranging from zero for most members of 
the population to a maximum value (established under Recommendation 4) 
accruing to a small number of individuals. The RPG serves as an upper 
bound on the highest doses resulting from the sum of all such 
distributions. As such, it acts as a limit on the annual increment of 
risk, now and in the future, to the theoretically most exposed 
individual with typical consumption and other relevant behavior habits.
    In selecting the proposed value for the RPG the Agency has had to 
consider a number of judgmental factors: the relation between a limit 
on annual dose and the implied lifetime risk; the degree of protection 
achieved through the application, by regulatory authorities, of 
optimization to the derivation of source limits, as well as their 
consideration of the various possibilities for multiple exposure to 
current and future sources, under Recommendation 4; and, finally, the 
record to date on the operational application of ALARA (i.e., the 
difference between source limits and the doses actually experienced).
    It is anticipated that the proposed RPG, applied in the context of 
these proposed recommendations, would, under most circumstances, result 
in lifetime risks to the most exposed members of the public from man-
made radiation in the environment of less than one in ten thousand. 
This expectation is based on past experience under current radiation 
protection guidance, cited above, coupled with the improvements in 
protection proposed here--most particularly those proposed under 
Recommendations 2, 3, and 4. Recommendation 2 strengthens the 
requirement that doses be maintained as low as reasonably achievable; 
Recommendation 3 reduces the RPG; and Recommendation 4 requires source-
specific limits that take into account the present and future potential 
for doses from other sources (and are therefore normally only a 
fraction of the RPG). EPA has, in a number of previous actions, 
concluded that a lifetime risk level no greater than about one in ten 
thousand provides an acceptable level of protection. These include the 
National Emission Standards for Hazardous Air Pollutants (NESHAPs), the 
National Primary Drinking Water Standards, and the Agency's guidelines 
for site-specific risk management under the Comprehensive Environmental 
Response, Compensation, and Liability Act (``Superfund''). These 
recommendations propose that this level of protection is also 
appropriate for application in this Federal Radiation Protection 
Guidance for Exposure of the General Public and would be achieved 
through the cumulative application of these recommendations.
    In addition, the proposed five-fold reduction in the RPG and the 
accompanying requirement that it be applied to the sum of external and 
committed internal doses would assure that maximum risks permitted to 
even the most highly exposed individuals are greatly reduced, compared 
to those permitted under the current RPGs. Although not many people are 
exposed near the RPG, a few cases of such high risks do now exist. 
These are usually associated with technologically enhanced exposure to 
natural radioactive materials. Examples include phosphate mining 
residues in Idaho and Florida, radium processing wastes in New Jersey, 
Illinois, and Colorado, and uranium mill tailings at publicly 
accessible locations in a number of western states. Under the current 
RPGs, annual doses due to external exposure up to 5 mSv (500 mrem) are 
permitted, in addition to organ doses from internal exposure up to 15 
mSv (1500 mrem), depending on the organ and the radionuclide. Such 
doses imply lifetime risks up to 250 in one million for each year of 
external exposure, and up to 40 in one million for each year of 
internal exposure. The proposed RPG of 1 mSv effective dose equivalent 
would limit the incremental lifetime risk associated with each year of 
combined external and internal exposure to 50 in one million, a 
significant reduction in risk.
    Finally, the Agency notes that the proposed RPG is consistent with 
levels found acceptable and in use by the international community. A 
value of 1 mSv per year is recommended as the upper bound on doses to 
members of the public by both the ICRP and the International Atomic 
Energy Agency, and is in common use throughout the world.
    To provide a perspective on the above levels of risk, it may be 
noted that the average American is exposed annually to an effective 
dose equivalent of about 3 mSv (300 mrem) from natural background 
radiation, including an average contribution of about 2 mSv (200 mrem) 
from radon in homes. This exposure is three times the proposed RPG, and 
each year's exposure corresponds to an incremental lifetime risk of 150 
in one million. Although the average level of exposure to natural 
background provides perspective, it does not, however, provide a 
justification for the RPG, since it represents an uncontrollable source 
of risk, and the RPG applies to controllable sources.
    The levels of risk assumed to be associated with radiation exposure 
may also be compared to involuntary and voluntary risks actually 
incurred in common activities. For example, the essentially involuntary 
risk of dying of a household accident averaged about 110 in a million 
per year, between 1980 and 1990, and the average probability of dying 
of an automobile accident in the same decade, a voluntary risk, was 240 
in a million per year. We emphasize that all of these examples are 
provided for perspective only, and that the existence of other risks, 
voluntary or involuntary, is not a justification for any particular 
incremental radiation risk.
    EPA recognizes that some of the assumptions that underlie the 
proposed RPG are not readily quantified, or are based on experience 
that may not accurately predict the future. We will continue to review 
exposure of the general public, with a view to initiating 
recommendations for any further modification of these recommendations 
that may be warranted to ensure that low risks to individuals are 
maintained.

Other Matters Related to the Radiation Protection Guide

    In developing these recommendations, EPA also considered risk to 
the unborn from exposure of pregnant women. It is clear that, in 
general, the fetus is more sensitive to many environmental carcinogens, 
mutagens, and teratogens than are adults, because the rate of cell 
division in their developing organs is far greater. This appears to be 
the case for radiation as well, which can act in any of these three 
ways. Of these risks, the most important at the levels of exposure 
addressed by these recommendations is mental retardation due to 
exposure to radiation during the eighth to fifteenth weeks of 
gestation, as discussed earlier.
    In considering the importance of the risk of mental retardation to 
the choice of the RPG, we note that the sensitive period for inducing 
this effect represents a very small part (0.2%) of a normal lifetime, 
the time span addressed by the risk limitation contemplated by these 
recommendations. This sensitive period should be considered in 
conjunction with the observation that sources governed by these 
recommendations typically yield exposure that is uniformly distributed 
in time, and almost never yield high-level, short-duration doses. 
(Accidents are not addressed by this guidance.) Based on these two 
observations, coupled with the numerical values for radiation risks 
cited earlier, EPA concludes that the risk of mental retardation from 
the relatively small exposure of the unborn that would accumulate 
during the short period of sensitivity before birth will be smaller 
than the risk of cancer associated with the very much longer period 
following birth, during which time a relatively much larger exposure to 
sources governed by these recommendations could accumulate. EPA 
believes, further, that it is not appropriate to base a general limit 
for members of the public on the highly unlikely circumstance that the 
entire RPG is delivered during the short period of significantly 
elevated susceptibility of the unborn. We conclude, therefore, that 
these proposed recommendations would provide adequate protection of the 
unborn without specifying a separate limit specifically for this 
purpose.
    An opposite situation is posed in considering the risk to members 
of the population who are within one or two decades of the end of a 
normal lifetime. In this case the risk, instead of being higher, is 
lower. The risk of cancer in this population approaches being an order 
of magnitude smaller than the risk to an average member of the 
population, and the risk of genetic consequences is normally no longer 
present. EPA has not proposed a higher RPG for this population because, 
as noted for the case of the unborn, these recommendations are based on 
limiting the risks that accrue over a lifetime, not on a yearly basis. 
The RPG is expressed as an annual limit simply for ease of 
implementation. We also note that a limit that was different for 
different ages of members of the public would pose severe 
implementation difficulties.
    Implementation of measures for assessment and control of internal 
exposure to radionuclides commonly makes use of intake-to-dose 
conversion factors. EPA has previously tabulated such values for use in 
implementing the Federal Guidance for Protection of Workers, in Federal 
Guidance Report No. 11, Limiting Values of Radionuclide Intake and Air 
Concentration, and Dose Conversion Factors for Inhalation, Submersion, 
and Ingestion (EPA-520/1-88-020). The dose conversion factors in this 
report and its subsequent editions also apply to intake of 
radionuclides by members of the general public. For external sources, 
exposure-to-dose conversion factors are tabulated in Federal Guidance 
Report No. 12, External Exposure to Radionuclides in Air, Water, and 
Soil (EPA 402-R-93-081).
    These dose conversion factors are appropriate for application to 
any population adequately characterized by the set of values for 
physiological parameters developed by the ICRP and collectively known 
as ``Reference Man.''\23\ The actual dose to a particular individual 
from a given intake is dependent upon age and sex, as well as other 
characteristics. As noted earlier, implementing limits for the general 
public expressed as age and sex dependent quantities would be 
difficult. (Clearly, it would be impracticable to conduct an annual 
survey of age and sex at every location of a potential source of public 
exposure.) More importantly, the variability in dose due to these 
factors is comparable in magnitude to the uncertainty in our estimates 
of the risks which provide the basis for our choice of the RPG. For 
this reason EPA believes that, for the purpose of providing radiation 
protection under the conditions addressed by these recommendations, the 
assumptions exemplified by Reference Man adequately characterize the 
general public, and a detailed consideration of age and sex is not 
generally necessary. The most obvious exception is for large doses 
delivered in a short period of time, as in an accident, for which case 
the appropriate response is addressed by separate EPA recommendations 
(EPA-520/1-75-001-A).
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    \23\ICRP No. 23 Report of the Task Group on Reference Man, 1974.
---------------------------------------------------------------------------

    The proposed RPG is sufficiently small that the dose any organ 
might receive will be far below threshold levels for non-stochastic 
health effects (i.e. effects on health, such as burning of the skin, 
cataracts, impairment of fertility, and more serious effects which can 
lead to early death, all of which only occur when threshold levels of 
dose that are greater than 0.5 Sv (50 rem) are exceeded). That is, 
adequate protection of every organ from non-stochastic health effects 
is automatically ensured by the proposed RPG. These recommendations 
therefore do not include separate limits to prevent the occurrence of 
non-stochastic effects.
    The sum of weighted organ doses that comprises the effective dose 
equivalent does not include an allowance for cancers induced by 
irradiation of the skin. In some circumstances, however, in the 
assessment of total health detriment in populations, dose to the skin 
may be large enough to warrant consideration of fatal cancers due to 
skin dose. These proposed recommendations provide for adding to the 
effective dose equivalent a term that is the product of the dose 
equivalent to skin (averaged over the entire skin surface) and a 
weighting factor of wskin=0.01 in such cases.

Recommendation 4

    Recommendation 4 consists of two parts. The first reads:

    Authorized limits for sources should be established to ensure 
that individual and collective doses in current and future 
populations satisfy the objectives of this guidance. These limits 
may be developed for categories of sources or for specific sources. 
Authorized limits for sources should normally limit doses to a 
fraction of the Radiation Protection Guide for all sources combined.

    Authorized limits are standards, regulations, technical 
specifications, or other requirements established by a responsible 
authority to ensure that the objectives of this guidance with respect 
to limitation of doses will be satisfied. Implementation of the ALARA 
requirement (Recommendation 2) will involve consideration of collective 
doses to populations,\24\ of control mechanisms, and of other factors 
that will differ for each category of sources, and will usually lead to 
control levels that result in doses to individuals less than the RPG 
(Recommendation 3). However, there are many different categories of 
activities using radiation that can lead to exposure of members of the 
public. These currently include medical uses of radiation and their 
supporting activities; nuclear electric power facilities and their 
supporting fuel cycle facilities; research and industrial users; 
weapons production, storage, and disposal facilities; technologically-
enhanced exposure to natural radiation sources; consumer products; 
space applications; disposal sites for radioactive wastes; and 
decommissioned sites at which radioactive materials were formerly used. 
It is therefore also necessary to ensure that total doses to 
individuals, who may be exposed not only to more than one source in a 
given category in a few cases, but more often to a number of different 
categories of sources at one time, are not likely to exceed the RPG. It 
is not intended that this objective be implemented through 
apportionment of the RPG among categories of sources; this would be 
impracticable. Rather, this consideration, which must encompass the 
potential for doses to the general public both now and in the future, 
will necessarily be a broad judgment, based on general observations of 
the characteristics of existing activities, projections for their use 
in the future, and the potential for presently unidentified future 
uses.
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    \24\These recommendations are not intended to require numerical 
limits for collective dose. Although the determination of ALARA 
levels necessarily involves optimization of the collective dose, the 
regulations that implement these levels can be expressed in terms of 
individual or collective dose, total or concentration of activity 
released, installation and use of specified controls, or any other 
specification that the regulatory authority finds appropriate.
---------------------------------------------------------------------------

    To implement these objectives, authorities responsible for limiting 
exposure of the public should govern sources through use of 
``authorized limits'' established either for categories of similar 
sources or for specific sources. In establishing these authorized 
limits, since the ALARA process considers actual costs and capabilities 
of controls, it is important that assessments of doses to individuals 
and populations be carried out realistically and comprehensively. Such 
assessments should contain neither unnecessarily unrealistic 
assumptions that overestimate doses nor omit any significant 
contributions to risk or detriment, since either of these would 
invalidate the ALARA determination. Further, authorities should 
consider, in addition to the design capabilities of facilities for 
control of releases, expected departures from anticipated design 
performance. Finally, in the case of authorized limits established for 
broad categories of sources, the judgments will often necessarily be 
broad and may lead to somewhat higher values, with further 
implementation of the ALARA process left to management of the 
individual sources within a category.
    Authorized limits currently exist for a wide variety of sources, at 
levels that are fractions of the proposed RPG. For example, in 1977 EPA 
established general limits for dose received from all radionuclides, 
combined, via all exposure pathways, combined, from most facilities 
involved in the nuclear fuel cycle combined, including power reactors, 
in 40 CFR Part 190. The principal limit, 25 millirem (0.25 mSv) per 
year to the whole body, is 25% of the proposed RPG. Additional site 
specific limitations are established, for example, by the Nuclear 
Regulatory Commission in license conditions for individual commercial 
reactor sites, or in requirements for specific types of facilities, 
such as low level waste sites in 10 CFR Part 61. EPA has recently 
established source-specific limits for doses from all radionuclides, 
combined, via all air pathways from individual sources of radionuclide 
emissions, including all Federal facilities, in 40 CFR Part 61. These 
generally require limiting doses to 10 millirem (0.1 mSv) per year 
effective dose equivalent, or 10% of the proposed RPG. Finally, the 
national drinking water standards at 40 CFR Part 141 limit doses from 
water at the tap to 4 millirem (0.04 mSv) per year whole body or organ 
dose from all man-made radionuclides, or 4% or less of the proposed 
RPG. In each of these cases, the regulatory process, under the current 
recommendations, supplemented in some cases by additional statutory 
requirements, has resulted in requirements ensuring that maximum dose 
to individuals from a specific source or category of sources is a small 
fraction of the proposed RPG for dose from all sources combined. 
Although this situation is anticipated to continue, we believe it is 
prudent to note explicitly that authorized limits should normally 
satisfy this condition.
    Once such authorized limits are established, it will no longer be 
necessary to further evaluate contributions to doses from any other 
source as part of the management of the operations of a specific 
source. These requirements thus serve to avoid the need to perform 
detailed, and in some cases very difficult to validate, evaluations of 
the combined incremental doses from other sources at individual sites. 
Conversely, if these requirements are exceeded (or are absent), then 
such evaluations may be necessary to assure conformance to the RPG 
(Recommendation 3).
    The second part of Recommendation 4 reads:

    Sources should be designed not to exceed authorized limits, and 
should be operated so as to maintain doses to members of the general 
public as low as reasonably achievable within such limits.

    The ALARA principle applies not only to the establishment of 
authorized limits, but also to detailed management of facilities where 
sources of radiation are prepared, employed, stored, or transported. 
This is necessary and appropriate because authorized limits must 
usually provide flexibility for anticipated deviations from design 
performance, and controls usually can perform better than their design 
limits. Thus, exposure of the general public, even if a source conforms 
to authorized limits, will not be ALARA when lower exposures are 
reasonably achievable.
    As exemplified by the performance of many facilities over the past 
two decades, doses to the public usually can be maintained far below 
authorized limits through responsible and skillful control of radiation 
sources. This has required careful management and supervision of 
radiation protection activities, including the choice and 
implementation of radiation control measures for sources of exposure of 
members of the public, training in procedures to control such exposure, 
and monitoring, assessment, and reporting of exposure levels and doses 
at appropriate on-site and off-site locations. The routine management 
of a facility and decisions on how, or whether, particular actions 
should be carried out can, in the aggregate, be as (or more) 
significant for radiation protection of the public as the design of the 
facility and choice of its authorized limit.
    The selection of authorized limits and the application of the ALARA 
principle to operations requires technically informed judgments. Thus, 
the practice of ALARA must be the responsibility primarily of those 
persons who control and manage sources of radiation under the oversight 
of the responsible public authorities; that is, it should not be the 
responsibility of individual members of the public, who are not 
familiar with radiation protection practices. For example, consumer 
products containing radioactive materials, and instructions for their 
use and disposal, should be designed to maintain radiation doses that 
are ALARA, and members of the public who use them should not have to 
rely upon their own judgment on this issue. The ALARA principle must be 
implemented by those who are directly responsible for radiation 
protection, or who are otherwise professionally responsible for health, 
safety, and environmental protection aspects of radiation sources.

Recommendation 5

    Risks associated with exposure of the general public to 
radiation that may occur due to Federal agency decisions, and the 
policies upon which these decisions are based, should be made known 
to the public in a timely fashion as part of the decision process. 
The degree of detail and type of information made available should 
be appropriate to the potential radiation exposures involved. 
Information on risks should encompass estimates of the risks of 
effects on health over time, and of the uncertainties in such 
estimates. Information on policies should include reference to this 
Federal radiation protection guidance for the general public and 
other relevant Federal policies.

    To judge the validity and acceptability of decisions about Federal 
activities which not only bring benefits but also pose risks, the 
public requires clear and, to the extent possible, quantitative 
information. In the case of proposed Federal actions involving exposure 
to radiation, this includes information on the biological effects of 
radiation, on the levels of risk associated with exposures that may 
result from the actions, and on the Federal policies that underlie the 
action.
    Requirements for the development and presentation of these kinds of 
information may be found in the National Environmental Protection Act 
(NEPA), 42 U.S.C. Secs. 4231 et seq.; Title III of the Superfund 
Amendments and Reauthorization Act (SARA), 42 U.S.C. Secs. 9601 et 
seq.; the Administrative Procedure Act, 5 U.S.C. Secs. 551 et seq.; and 
in other legislation. Such information serves to assist the public in 
becoming constructively involved in the decision process and in 
influencing the public policy issues that affect them.
    It is the purpose of this recommendation to ensure that, when 
Federal agencies formulate policies and make decisions that influence 
the exposure of the general public, information that will adequately 
inform the public during the decision-making process is made available 
by them in a timely manner. Although it is not intended to require 
general dissemination of information concerning ongoing operations, nor 
to require major public information distribution efforts, such 
activities are encouraged whenever it is reasonable to carry them out.

Recommendation 6

    Assessments and records appropriate to the origin and magnitude 
of expected doses and the exposed population should be performed and 
maintained to demonstrate conformance with requirements which 
implement these recommendations. The types and accuracy of methods 
and procedures used in these assessments should be reviewed 
periodically to ensure that they are appropriate and are being 
competently applied.

    Control of exposure of the public is normally ensured through 
analysis of releases from sources and modeling of environmental 
transport to hypothetical ``critical groups'' of the general public 
assumed to receive the greatest exposure. Unlike the situation for 
workers exposed occupationally, it is usually neither appropriate nor 
feasible to physically monitor doses to individual members of the 
public. Such dose rates and concentrations may be determined by 
measurement of radioactive effluents, mathematical modeling of the 
dispersal of radionuclides in the environment, or both.
    Assessments and records required to ensure conformance with these 
recommendations will vary, depending upon the nature of the source of 
exposure. Responsible authorities will have to determine what is needed 
to ensure that exposures of members of the public actually are 
maintained within authorized limits and are ALARA. In some cases, 
comprehensive radiation assessment programs will be needed which 
include trained personnel, facility and environmental measurements, 
audit procedures, and maintenance of records. In many cases 
conservative assumptions, such as the assessment of doses to a 
hypothetically most exposed individual, may be used to simplify the 
demonstration of compliance. In still others, simple operational 
procedures will suffice.
    This recommendation intentionally allows flexibility with respect 
to what should be assessed and recorded, so that the responsible 
authorities will be able to design optimal programs for each situation. 
This is intended to avoid, in particular, burdensome requirements for 
situations in which individual doses and detriments to populations are 
very low. At the same time, assessments and recordkeeping must be 
adequate to document that requirements which implement these 
recommendations have been satisfied.

Recommendation 7

    Exceptions to Recommendation 3 for planned exposure to radiation 
should be made only for highly unusual circumstances, and only when 
the Federal agency having jurisdiction has carefully considered the 
reasons for making them in light of these recommendations. If 
Federal agencies authorize any exception to these values, they 
should make it a matter of public record.

    This proposed guidance applies to emissions and exposure of the 
general public under normal circumstances. In developing these 
recommendations, EPA has considered situations that might normally 
arise. It is not possible to foresee all contingencies, however, and 
highly unusual situations may occur when exceptions to the limiting 
values of Recommendation 3 are appropriate. This recommendation 
provides that if such circumstances should arise, Federal agencies 
should carefully consider the balance of the guidance, including the 
information requirements of Recommendation 5, and make a public record 
of any authorized exception to Recommendation 3 (e.g., by publishing a 
notice in the Federal Register or in a local newspaper of general 
circulation).

Implications of these Recommendations

    It is expected that these proposed recommendations could be 
implemented relatively easily, since most of them are already, in large 
part, in effect. For example, most sources are already regulated in 
such fashion that exposures of members of the public are a small 
fraction of the proposed Radiation Protection Guide of 1 mSv (100 mrem) 
in a year, and we are aware of no regulated sources that exceed the 
proposed RPG. Perhaps the most significant implication of these 
recommendations would be to promote consistency between Federal 
agencies by clarifying the basic considerations to be taken into 
account in the development of new standards and regulations, and in 
their implementation. The recommendations modernize the methodology for 
expressing dose, and clarify the relationship of the RPG to standards 
and regulations for sources, as well as the various applications of the 
principle that doses should be maintained ``as low as reasonably 
achievable,'' and they provide, for the first time as a part of their 
basis, numerical estimates of the various risks from low levels of 
ionizing radiation.
    Implementation of the proposed recommendations would require only 
minimal changes in Federal regulations, and should be achievable over a 
short period of time. Many of the changes called for are largely 
already well under way, major examples being the revisions recently 
made by the Department of Energy in their Order No. 5400.5, and those 
recently promulgated by the Nuclear Regulatory Commission in 10 CFR 
Part 20. It is expected that Federal agencies will have little 
difficulty in identifying and correcting any remaining problem areas, 
and in providing necessary flexibility and transition periods, to avoid 
undue impacts that might inhibit prompt implementation of new guidance.
    We note in passing that in some cases (notably in the regulation of 
exposure of the public from the transportation of radioactive 
materials) conformance to existing guidance is based upon the 
assumption of ``reasonably foreseeable'' scenarios for the spatial and 
temporal relationship between radioactive materials and members of the 
public, and that because of this assurance the RPG will never be 
exceeded cannot be given with absolute certainty. These recommendations 
do not propose any changes in this regard, and EPA expects that in such 
cases the same approach to protection would continue to be employed to 
achieve conformance to these new recommendations.
    The anticipated costs of implementing these recommendations are 
primarily those that would be incurred by the various agencies in 
modifying their own regulations. These are not expected to be 
substantial, since most of the necessary methodological changes have 
already been implemented in connection with the revised Federal 
guidance for occupational exposure issued in 1987. Unlike the situation 
for occupational exposure, where the need to reduce the doses received 
by a few highly exposed workers to conform to lower limits may lead, in 
some cases, to the hiring and training of additional workers, there are 
few direct implementation costs involved here, since most sources are 
already regulated to well within the proposed new requirements.
    This guidance would not supersede any statutory responsibilities of 
the agencies that would implement these recommendations, and in some 
situations application of these recommendations could be superseded by 
specific statutory requirements. In addition, it does not create any 
new authority. As noted earlier, it is the purpose of this Federal 
guidance to provide a common framework to help ensure that the 
management of exposure to radiation in the United States is consistent 
and adequately protective. This can be carried out through regulations 
applicable to the public sector, through orders applicable to the 
internal operations of Federal agencies, through guidance, or by any 
other practicable means. The individual Federal agencies, based on 
their statutory and administrative mandates, have determined, and would 
continue to determine, the details of specific regulations, orders, 
guidance, or other actions, the parties responsible for implementing 
them, and the means to do this.
    The proposed recommendations differ from current guidance in 
significant ways. The Radiation Protection Guide for maximum radiation 
dose to a member of the public in a year is reduced by a factor of 
five, from 500 mrem to 1 mSv (100 mrem). The concept of risk-based 
weighting of doses to different parts of the body is adopted, and the 
committed dose is introduced as the primary basis for control of 
internal exposure. The RPG now applies to the sum of external and 
internal exposure. Increased emphasis is placed on keeping justified 
exposure as low as reasonably achievable (ALARA), and on the 
comprehensive consideration of doses in populations near and distant, 
now and in the future. The establishment of authorized limits for 
sources or categories of sources that are derived giving consideration 
to the wide variety of potential sources and their future implications 
for exposure that, combined, must be maintained within the RPG, and 
from the comprehensive application of ALARA, is recommended. The 
proposed recommendations recognize, for the first time in this Federal 
guidance, the importance of public information and of assessing and 
recording public exposures. Finally, these recommendations would bring 
U.S. radiation protection policy into conformance with that in general 
international use. EPA expects these changes would strengthen the 
overall system for radiation protection of the members of the public in 
the United States.
    These recommendations would replace those portions of current 
Federal Radiation Protection Guidance (25 FR 4402) that apply to 
protection of the general public from ionizing radiation. It is 
expected that individual Federal agencies, on the basis of their 
knowledge of specific sources of exposure of the general public, would 
use this new guidance as the basis upon which to revise or develop 
detailed standards or regulations, to the extent that they have 
regulatory or administrative jurisdiction. Pursuant to my 
responsibilities under Executive Order 10831, the Atomic Energy Act of 
1954, as amended, and Reorganization Plan No. 3 of 1970, I would 
propose to keep informed of Federal agency actions to implement this 
guidance and to interpret and clarify these recommendations, and, in 
consultation with affected Federal agencies, from time to time amend 
the clarifying notes to reflect new technical information, as necessary 
to promote a consistent and effective Federal program of protection of 
the public from radiation.

Request for Comments

    EPA requests comments on any and all aspects of these proposed 
recommendations. We would, for example, appreciate comment on the 
overall approach to protection of the public embodied by these 
proposals, which would continue and expand upon the approach 
recommended for protection against the effects of exposure to radiation 
by national and international professional advisory bodies, and which 
has formed the basis for previous guidance to Federal agencies. In 
addition to general comments, we are also particularly interested in 
commenter's views on the following specific matters:
    1. Should EPA consider a lower or higher value for the Radiation 
Protection Guide (RPG); e.g., 0.3, 0.5, or 1.5 mSv (30, 50, or 150 
mrem)? What would be the rationale for such a value? If a lower value 
is adopted would it be necessary to modify Recommendation 4, and, if 
so, how could it be modified to retain flexibility to provide for 
possible future beneficial uses?
    2. Is it necessary to provide, in Recommendation 3, for temporary 
exposures as high as 5 mSv (500 mrem). What specific examples of 
situations that justify this proposed provision currently exist, or 
have a high probability of occurring in the future?
    3. Should the guidance recommend a single maximum risk (or dose) 
level for individual sources, under Recommendation 4, which would serve 
as an upper bound on all ALARA determinations? If this approach were 
adopted, would the RPG in Recommendation 3 become superfluous?
    4. Should the recommendations provide guidance on the kinds of 
situations under which it would be appropriate for a Federal agency to 
invoke Recommendation 7. Are there foreseeable situations that require 
the existence of this proposed provision?
    5. Should EPA initiate proposals to update the weighting factors 
for effective dose now. If so, what basis or values for these factors 
should we consider?
    6. Has EPA correctly characterized the cost of implementing these 
recommendations. If not, what specific costs have we not identified, 
what is their estimated magnitude, and what is the basis for this 
estimate?
    7. These proposals do not express a preference between historical 
radiation units, commonly used in health physics practice, and the new 
system of units (SI) now in scientific and international health physics 
use. Should they?
    8. These proposed recommendations do not address protection of 
animals and plants. Are the proposed levels adequate to protect all 
plant and animal species? If not, what level would provide adequate 
protection? Is protection at the level of species the appropriate 
choice?
    EPA will carefully consider all written responses to this request 
for comments, and we encourage interested parties to present their 
views at the public hearing that will be held on these proposals. 
Following these hearings we will, after consulting with affected 
Federal agencies, formulate and transmit final recommendations to the 
President for revisions to Federal radiation protection guidance for 
exposure of the general public.

    Dated: December 14, 1994.
Carol M. Browner,
Administrator.

Proposed Recommendations

    The following recommendations are made for the guidance of Federal 
agencies in the formulation of regulations and conduct of programs for 
the protection of the general public from ionizing radiation. Their 
objective is to ensure that exposure to ionizing radiation is 
restricted to levels that will not produce undue risk to individuals or 
undue harm in populations.a The recommendations apply to radiation 
exposure other than that from background radiation or received as a 
patient in the practice of the healing arts, as a worker, or as the 
result of an accident. (See Notes 1 and 2.)
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    \a\The term ``risk,'' as used here, means the statistical 
probability of harm to the health of an individual from exposure to 
radiation. ``Harm in populations'' from exposure to radiation, 
called the radiation ``detriment'', means the mathematical 
expectation of harm in the population, taking into account the 
probabilities and the severities of different deleterious effects.
---------------------------------------------------------------------------

    1. There should be no exposure of the general public to ionizing 
radiation unless it is justified by the expectation of an overall 
benefit from the activity causing the exposure. Justified activities 
may be allowed, provided exposure of the general public is limited in 
accordance with these recommendations.
    2. A sustained effort should be made to ensure that doses to 
individuals and to populations are maintained as low as reasonably 
achievable. (See Note 3.)
    3. The combined radiation doses incurred in any single year from 
all sources of exposure covered by these recommendations should not 
normally exceed a Radiation Protection Guide of 1 mSv (100 mrem) 
effective dose equivalentb to an individual.c The Radiation 
Protection Guide applies to the sum of the effective dose equivalent 
resulting from exposure to external sources of radiation during a year 
and the committed effective dose equivalent incurred from the intake of 
radionuclides during that year. (See Notes 4 through 7.)
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    \b\Effective dose equivalent is a derived quantity defined as 
the risk-weighted sum of dose equivalents to specified organs and 
tissues.
    Dose equivalent is the product of the absorbed dose and a 
quality factor which varies with the energy and type of radiation. 
In the system of quantities of ionizing radiation historically in 
use in the United States, the unit of dose equivalent is the 
``rem.'' In the international system (S.I.), the corresponding unit 
is the ``sievert'' (Sv). One sievert equals 100 rem.
    The effective dose equivalent, HE, incurred in a given 
period of time is the sum of the effective dose equivalent, 
HE,ext, received from external exposure in that period and the 
committed effective dose equivalent, HE,50, incurred from the 
intake of radionuclides during that period. That is,

    E=HE,ext + HE,50 =T 
wt(H,ext + HT,50),

    where wT is a weighting factor for organ or tissue T; 
HT,ext is the dose equivalent from external irradiation 
averaged over organ or tissue T; and HT,50, the committed dose 
equivalent, is the sum of all dose equivalnts, averaged over organ 
or tissue T, that may accumulate over an individual's anticipated 
remaining lifetime (taken as 50 years) from radionuclides retained 
within the body. The weighting factors satisfy the condition 
T wt = 1.
    The word ``dose'', when used alone in these recommendations, is 
intended to carry the specific dose unit implied by the surrounding 
text.
    \c\The term ``individual'' means a typical member of any 
critical group of most highly exposed members of the general public; 
it refers to persons with typical consumption and other relevant 
behavior habits.
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    The Radiation Protection Guide may not be reasonably achievable in 
some unusual situations. It may be exceeded temporarily in situations 
that are not anticipated to recur chronically and when Recommendations 
1 and 2 are satisfied, provided that the radiation dose incurred in any 
year does not exceed 5 mSv (500 mrem) effective dose equivalent.
    Continued exposure of an individual over substantial portions of a 
lifetime at or near the level of the Radiation Protection Guide should 
be avoided. This will normally be achieved through conformance of 
individual sources to Recommendations 2 and 4.
    4. Authorized limitsd for sources should be established to 
ensure that individual and collective doses in current and future 
populations satisfy the objectives of this guidance. These limits may 
be developed for categories of sources or for specific sources. 
Authorized limits for sources should normally limit doses to a fraction 
of the Radiation Protection Guide for all sources combined. (See Note 
8.)
---------------------------------------------------------------------------

    \d\Authorized limits are standards, regulations, or other 
requirements established by a responsible authority for categories 
of sources or for a specific source.
---------------------------------------------------------------------------

    Sources should be designed not to exceed authorized limits, and 
should be operated so as to maintain doses to members of the general 
public as low as reasonably achievable within such limits.
    5. Risks associated with exposure of the general public to 
radiation that may occur due to Federal agency decisions, and the 
policies upon which these actions are based, should be made known to 
the public as part of the decision process. The degree of detail and 
type of information made available should be appropriate to the 
potential radiation exposures involved. Information on risks should 
encompass estimates of the risks of effects on health over time, and of 
the uncertainties in such estimates. Information on policies should 
include reference to this Federal radiation protection guidance for the 
general public and other relevant Federal policies.
    6. Assessments and records appropriate to the origin and magnitude 
of expected doses and the exposed population should be performed and 
maintained to demonstrate conformance with requirements which implement 
these recommendations. The types and accuracy of methods and procedures 
used in these assessments should be reviewed periodically to ensure 
that they are appropriate and are being competently applied.
    7. Exceptions to Recommendation 3 for planned exposure to radiation 
should be made only for highly unusual circumstances, and only when the 
Federal agency having jurisdiction has carefully considered the reasons 
for making them in light of these recommendations. If Federal agencies 
authorize any exception to these values, they should make it a matter 
of public record.

Notes

    The following notes are provided to clarify application of the 
above recommendations:
    1. Background radiation includes natural sources of background 
radiation, such as cosmic radiation and radiation from naturally-
occurring radionuclides undisturbed by human activities, as well as 
radiation from certain other sources of exposure beyond Federal 
regulatory control, such as residual fallout from past nuclear 
accidents and weapons tests.
    2. People may, by technological means, enhance their exposure to 
natural radiation sources that might otherwise be considered sources of 
background radiation. Technologically-enhanced exposures to natural 
radiation are usually controllable, in that they may be avoided or 
reduced by taking reasonable actions. Unless specifically noted, these 
recommendations apply to controllable technologically-enhanced exposure 
to such natural radiation sources.
    3. The admonition to maintain doses ``as low as reasonably 
achievable'' includes consideration of economic and societal factors, 
and applies to radiation exposure that may occur now or in the 
foreseeable future. In making this judgment for doses to populations, 
any incremental doses to individuals that are avoidable and which make 
a significant contribution to collective dose should be considered.
    4. Although indoor radon from proximate natural sources is 
considered technologically-enhanced exposure to natural radiation, 
Recommendations 3 and 4 of this guidance do not apply to such exposure. 
Specific advice for protection against exposure to indoor radon is 
provided in A Citizen's Guide To Radon (EPA document 402-K92-001 and 
subsequent editions) and in other EPA technical publications.
    5. The following values of the weighting factors wT may be 
used to implement these recommendations:

Gonads...........................................................   0.25
Breasts..........................................................   0.15
Red bone marrow..................................................   0.12
Lungs............................................................   0.12
Thyroid..........................................................   0.03
Bone surfaces....................................................   0.03
Remainder........................................................   0.30
                                                                        

(``Remainder'' applies to the five other organs with the highest doses 
(of the liver, kidneys, spleen, brain, thymus, adrenals, pancreas, 
stomach, small intestine, and upper or lower large intestine, but 
excluding skin, lens of eye, and extremities). The weighting factor for 
each such organ is 0.06.)
    6. The sum of weighted organ doses that comprises the effective 
dose equivalent does not include an allowance for the induction of 
fatal cancers in skin. In cases where dose to skin is large enough to 
consider such effects, this may be done by adding to the effective dose 
equivalent a terme that is the product of the skin dose equivalent 
(averaged over the whole body) and a weighting factor wskin = 
0.01.
---------------------------------------------------------------------------

    \e\Since the sum of the weighting factors is normalized to 
unity, addition of a further factor would strictly require 
adjustment of the other factors. In practice, the addition of this 
small factor for skin does not warrant any change.
---------------------------------------------------------------------------

    7. The exposure-to-dose conversion factors tabulated in Federal 
Guidance Report No. 11 (EPA-520/1-88-020), Federal Guidance Report No. 
12 (EPA 402-R-93-081), and their subsequent editions should be used for 
determining conformance to these recommendations. In addition, 
dosimetric models and conventions and models for reference persons 
specified by the International Commission on Radiological Protection 
(ICRP) may be used. Under special circumstances, other factors may be 
used when such factors are more appropriate on the basis of well-
established scientific evidence.
    8. To ensure that specific sources or categories of sources, 
including their installed control capability, are designed and operated 
to achieve as low as reasonably achievable levels of exposure, a 
variety of quantitative and qualitative analysis and decision methods 
may be used to determine authorized limits. These, in addition to 
considering radiation detriment and risk, and direct costs, may also 
take into account societal and other economic factors. Statutory 
requirements may impose additional constraints on the selection of 
authorized limits.

[FR Doc. 94-31618 Filed 12-22-94; 8:45 am]
BILLING CODE 6560-50-P