FOREWORD 

.Public officials are charged with the responsibility to protect the health of 

the public during hazardous incidents. The purpose ofthis manual is to assist 

these officials in establishing emergency response plans and in making decisions 

during a nuclear incident. It provides radiological protection guidance that may 

be used for responding to any type of nuclear incident or radiological emergency, 

except nuclear war. 

Under regulations governing radiological emergency planning and 

preparedness issued by the Federal Emergency Management Agency ( 4 7 FR 

10758, March 11, 1982), the Environmental Protection Agency's responsibilities 

include, among others, (1) establishing Protective Action Guides (PAGs), (2) 

preparing guidance on implementing PAGs, including recommendations on 

protective actions, (3) developing and promulgating guidance to State and local 

governments on the preparation of emergency response plans, and ( 4) developing, 

implementing, and presenting training programs for State and local officials on 

PAGs and protective actions, radiation dose assessment, and decision making. 

This document is intended to respond to the first two responsibilities. 

The manual begins with a general discussion of Protective Action Guides 

(PAGs) and their use in planning for protective actions to safeguard public health. 

It then presents P AGs for specific exposure pathways and associated time periods. 

These P AGs apply to all types of nuclear incidents. This is followed by guidance 

for the implementation of PAGs. Finally, appendices provide definitions, 

background information on health risks, and other information supporting the 

choice of the numerical values ofthe PAGs. 

P AGs for protection from an airborne plume during the early phase of an 

incident at a nuclear power plant were published in the 1980 edition of this 

manual. These have now been revised to apply to a much broader range of 

situations and replace the PAGs formerly published in Chapters 2 and 5. 

Recommendations and background information for protection from ingestion of 

contaminated food were published by the Food and Drug Admjnjstration in 1982. 

These are reprinted here as Chapter 3 and Appendix D. Recommendations for 

P AGs for relocation are presented in Chapters 4 and 7. Additional radiation 

protection guidance for recovery will be developed at a later date. We are 

continuing work to develop PAGs for drinking water and, in cooperation with 

FDA, revised P AGs for food. When experience has been gained in the application 

of these PAGs, they will be reexamined and refined as necessary, proposed for 

review, and then recommended to the President as Federal radiation protection 

guidance. 

111 
This manual is bei,ng re-published to consolidate existing recommendations 

in a single volume. As revised and additional recommendations are developed, 

they will be issued as revisions to this manual. These revised PAGs are 

appropriate for incorporation into emergency response plans when they are revised 

or when new plans are developed. However, it is important to recognize that 

regulatory requirements 'for emergency response are not provided by this manual; 

they are established by the cognizant agency (e.g., the Nuclear Regulatory 

Commission in the case of commer~al nuclear reactors, or the Department of 

Energy in the case of their contractor-operated nuclear facilities). 

Users of this mant,~al are encouraged to provide comments and suggestions 

for improving its contents. Comments should be sent to Allan C. B. Richardson, 

Criteria and Standards I)ivision (ANR-460), Office of Radiation Programs, U.S. 

Environmental Protectio:p. Agency, Washington, DC 20460. 

' 

/}~f. ckk ~T.Oge 0 

Director, Office of 

Radiation Programs 

Washington, D.C. 

iv 
CONTENTS 


Page 


Foreword . . . . .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 111 


1.. Overview. . . ............................................ 1-1 


1.0 Introduction ...........................·.............. 1-1 


1.1 Nuclear Incident Phases and Protective Actions ............. 1-2 


1.2 Basis for Selecting P AGs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-5 


1.3 Planning .. ·...................... , .... 1 	

•••••••••• · •••• 1-6


1.4 Implementation of Protective Action ...................... 1-6 


References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-7 


2. Protective Action Guides for the Early Phase of an Atmospheric Release 2-1 


2.1 Introduction ......................................... 2-1 


2.1.1 Applicability .................................... 2-1 


2.1.2 Emergency Planning Zones and the PAGs ............. 2-2 


2.1.3 Incident Phase .................................. 2-3 


2.2 Exposure Pathways ................................... 2-3 


2.3 The Protective Action Guides ............................ 2-4 


2.3.1 Evacuation and Sheltering ......................... 2-5 


2.3.2 Thyroid and Skin Protection ........................ 2-7 


2.4 Dose Projection ...................................... 2-8 


2.5 Guidance for Controlling Doses to Workers Under 


Emergency Conditions ............................ 2-9 


References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-13 


3. Protective Action Guides for the Intermediate Phase (Food and Water) 3-1 


4. 	 Protective Action Guides for the Intermediate Phase 


(Deposited Radioactive Materials) ........................ 4-1 


4.1 Introduction ......................................... 4-1 


4.1.1 Exposure Pathways ..................... ·.......... 4-2 


v 
Page 

4.1.2 The Population Affected ........................... 4-3 


4.2 The Protective Action Guides for Deposited Radioactivity ...... 4-3 


4.2.1 Longer Term Objectives of the Protective Action Guides ... 4-4 


4.2.2 Applying the Protective Action Guides for Relocation ..... 4-5 


4.3 Exposure Limits for Persons Reentering the Restricted Zone .... 4-6 


References .............................................. 4-6 


5. Implementing the Protective Action Guides for the Early Phase ..... 5-1 


5.1 Introduction ............................... , ......... 5-1 


5.2 Initial Response and Sequence ofSubsequent Actions ......... 5-1 


5.2.1 Notification ..................................... 5-3 


5.2.2 Immediate Protective Action ....................... 5-3 


5.3 The Establishment of Exposure Patterns ................... 5-4 


5.4 Dose Projection ...................................... 5-6 


5.4.1 Duration of Exposure ............................. 5-6 


5.4.2 Dose Conversion Factors .......................... 5-8 


5.4.3 Comparison with Previously-Recommended PAGs ...... 5-16 


5.5 Protective Actions ................................... 5-17 


5.5.1 Evacuation ..................................... 5-18 


5.5.2 Sheltering .................................... 5-19 


5.5.3 General Guidance for Evacuation and Sheltering ....... 5-21 


5.6 Procedures for Calculating Dose Conversion Factors ; ........ 5-22 


5.6.1 Extemal Exposure to Gamma Radiation from the Plume . 5-23 


5.6.2 Inhalation from the Plume ........................ 5-23 


5.6.3 Extemal Dose from Deposited Materials ............. 5-24 


References ....................................... ·. . . . . . . 5-42 · 


V1 
Page 

6. 	 Implementing the Protective Action Guides for the Intermediate Phase 


(Food and Water) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6·1 


7. 	 Implementing the Protective Action Guides for the Intermediate Phase 


(Exposure to Deposited Materials) ...........•............. 7 • 1 


7.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7 • 1 


7.1.1 Protective Actions ............................... 7·2 


7.1.2 Areas Involved .................................. 7·2 


7.1.3 Sequence of Events . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7 ·4 

7.2 Establishment of Isodose-Rate Lines . . . . . . . . . . . . . . . . . . . . . . 7-6 


"7.3 Dose Projection . .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7-7 


~\: 

7.3.1 Projected External Gamma Dose .................... 7-8 


7.3.2 Inhalation Dose Projection ..."~ ....... ~ ............ 7-14 


7.4 Priorities .............................. ~ . . . . . . . . . . . . 7-17 


1.5 Reentry . . . . . . . . . . . . . . . . ; . . . ; . . ·. . . . . . ,. . . . . . . . . . . . . . . ·7-17 


7.6 Surface Contamination Control ...._... ~ ................. 7-19 


7.6.1 Considerations and Constraints .................... 7~19 

7.6.2 Numerical Relationships ......................... 7-21 


7.6.3 Recommended Surface Contamination LimitS· ... ~ ...... 7-21 


References . . . . . . . . . . . . . . . . . . . . . . . . -. . . . . . . . . . . . . . . . . . . . . 7-25 
 ' . i 


8. 	 Radiation Protection Guidance for the Late~J?hase (Recovery) (reserved) 8-1 


TABLES 

1-1 Exposure Pathways, Accident Phases, and Pr9tective Actions · ....... 1-4 


2-1 -Protective Actions Guides for·the Early Phase .ofa Nuclear Incident .. 2-6 


2-2 Guidance on Dose Limits for Workers Performin~ Emergency Services 2-10 


2-3 	Health Effects Associated with Whole-Body Absorbed Doses 


Received Within a Few Hours (see Appendix B) . ·~· ............... 2-12 


vii 
Page 

2-4 Approximate Cancer Risk to Average Individuals from 25 Rem 


Effective Dose Equivalent Delivered Promptly (see Appendix C) . . . . 2-12 


4-1 Protective Action Guides for Exposure to Deposited Radioactivity 

During the Intermediate Phase of a Nuclear Incident ............. 4-4 , 

5-1 Dose Conversion Factors (DCF) and Derived Response Levels (DRL) 


for Combined Exposure Pathways During the Early Phase of 


a Nuclear Incident . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-9 


5-2 Dose Conversion Factors (DCF) and Derived Response Levels (DRL) 


Corresponding to a 5 rem Thyroid Dose Equivalent from 


Inhalation of Radioiodine . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-15 


5-3 Dose Conversion Factors (DCF) and Derived Response Levels (DRL) 


for External Exposure Due to Immersion in Contaminated Air . . . . . 5-25 


5-4 Dose Conversion Factors (DOF) and Derived Response Levels (DRL) 


for Doses Due to Inhalation ................................ 5-31 


5-5 Dose Conversion Factors (DCF) and Derived Response Levels (DRL) 


for a 4-Day Exposure to Gamma Radiation 


from Deposited Radionuclides . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-37 


7-1 	Gamma Exposure Rate and Effective Dose Equivalent (Corrected 


for Radioactive Decay and Weathering) due to an Initial Uniform 


Concentration of 1 pCi/m2 on Ground Surface ................... 7-9 


7-2 Exposure Rate and the Effective Dose Equivalent (Corrected for 


Radioactive Decay) due to an Initial Concentration of 1 p(,'tifm 


on Ground Surface . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7-10 


7-3 Example Calculation of Dose Conversion Factors for Gamma Exposure 


Rate Measurements Based on Measured Isotopic Concentrations . . . . 7-13 


7-4 Dose Conversion Factors for Inhalation of Resuspended Material . . . 7-16 


7-5 	 Skin Beta Dose Conversion Factors for Deposited Radionu.clides .... 7-25 


7-6 Recommended Surface Contamination Screening Levels for 

Emergency Screening Levels for Emergency Screening of Persons 

Vlll 
Page 

. 	 ~·.;;,: ·;.:.~' 

and Other Surfaces at Screening or Monitoring Stations in High 

Background Radiation Areas . . . . . . . . . . . . . . . . . . ............ 7-23 

7-7 Recommended Surface Contamination Screening Levels for Persons 

and Other Surfaces at Monitoring Stations in Low 

Background Radiation Areas . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7-24 

FIGURES 

7-1 Response Areas . . . . .· . . . . . . . . . . . . . . . · . . . . . . . . . · . . . . . . . . . . . . . . 7-3 

7-2 Time Frame of Response to a Major Nuclear Reactor Accident ....... 7-6 

APPENDICES 

A. 	 Glossary 

B. 	 Risks to Health From Radiation Doses that may ResUlt from 

Nuclear Incidents 

C. 	 Protective Action Guides for the Early Phase: Supporting Information 

D. 	 Background for Protective A~tion Recommendations: Accidental 

Contamination of Food and Animal Feeds 

E. 	 Protective Action Guides for the Intermedlate Phase (Relocation) 

. Background Information 

F. 	 Radiation Protective Criteria for the Late Phase: Supporting 

Information (Reserved) · 

',.( 

! . 1X 

CHAPTER I 


Overview 


1.0 Introduction 

Public officials, in discharging their 

responsibility to protect the health of 

the public during hazardous situations, 

will usually be faced with decisions 

that must be made in a short period of 

time. A number of factors influencing 

the choice of protective actions will 

exist, so that the decisions may be 

complex. Further, all of the 

information needed to make the 

optimum choice will usually not be 

immediately available. In such situations, it will therefore be helpful ifthe 

complexity of the information upon 

which needed decisions are based can 

be reduced by careful planning during 

the formulation of emergency response 

plans. 

The U.S. Environmental Protection 

Agency has developed this manual to 

assist public officials in planning for 

emergency response to nuclear 

incidents. In the context of this 

manual, a nuclear incident is defined 

as an event or a seJ;ies of events, either 

deliberate or accidental, leading to the 

release, or potential release, into the 

environment ofradioactive materials in 

sufficient quantity to warrant 

consideration · of protective actions. 

(The term "incident" includes accidents, 

in the context of this manual.) A 

radiological emergency may resultfrom 

an incident at a variety of types of 

facilities, including, but not limited to, 

those that are part of the nuclear fuel 

cycle, defense and research facilities, 

and facilities that produce or use 

radioisotopes, or from an incident 

connected with the transportation or 

use ofradioactive materials at locations 

not:, classified as "facilities". This 

mal}1,1al provides radiological protection 

criteria intended for application to all 

nuclear incidents requ1nng 

consideration of protective actions, 

other than nuclear war. It is designed 

for the use of those in Federal, State, 

and local government with 

responsibility for emergency response 

planning. The manual also provides 

guidance for implementation of the 

criteria. This has been developed 

primarily for incidents at nuclear 

power facilities. Although this implementation guidance is intended to be 

useful for application at other facilities 

or uses of radioactivity, emergency 

response plans will require the 

development of additional 

implementation procedures when 

physical characteristics of the 

radionuclides involved are different 

from those considered here. 

The decision to advise members of 

the public to take an action to protect 

themselves from radiation from a 

nuclear incident involves a complex 

judgment in which the risk avoided by 

the protective action must be weighed 

in the context of the risks involved in 

taking the action. Furthermore, the 

1-1 

decision may have to be made under 

emergency conditions, with littie or no 

detailed information available. 

Therefore, considerable planning is 

necessary to reduce to a manageable 

level the complexity of decisions 

required to effectively protect the 

public at the time of an incident. 

An objective ofemergency planning 

is to simplify the choice of possible 

responses so that judgments are 

required only for viable · and useful 

alternatives when an emergency 

occurs. During the pla.n.niD.g process it 

is possible to make some value 

judgments and to determine which 

responses are not required, which 

decisions can be made on the basis of 

prior judgments, and which judgments 

must be made during an actual 

emergency. From this exercise, it is 

then possible to devise operational 

plans which can be used to respond to 

the spectrum of hazardou's situations 

which may develop. 

The main contribution to the 

protection ofthe public from abnormal 

releases of radioactive material is 

provided by site selection, design, 

quality assurance in construction, 

engineered safety systems, and the 

competence of staff in safe operation 

and maintenance. These measures can 

reduce both the probability and the 

magnitude ofpotential consequences of 

an accident. Despite these measures, 

the occurrence of nuclear incidents 

cannotbe excluded. Accordingly, emergency response planning to mitigate 

the consequences of an incident is a 

necessary supplementary level of 

protection. 

During a nuclear incident, when 

the source of exposure of the public, is 

not under control, the public usually 

can be protected only by some form of 

intervention which will disrupt normal 

living. Such intervention is termed 

protective actiofl:. A Protective Action 

Guide (PAG) is the projected dose· to 

reference man, or .other defiried 

individual, from an unplanned release 

of radioactive material at which a 

specific protective action to reduce . or 

avoid that dose is recommended. The 

objective of this manual is to provide 

such PAGs for the principal protective 

actions available to public officials 

during a nuclear incident, and ' to 

provide guidance for their use. 

1.1 Nuclear Incident Phases and 

Protective Actions 

It is convenient to identify three 

time phases which are generally 

accep~ed as being common to all 

nuclear incident sequences; within 

each, different considerations apply to 

most protective. actions. These are 

termed the early, intermediate, and 

late phases. Although these phases 

cannot be represented by precise 

periods and may overlap, they provide 

a· useful framework for the· 

considerations involved in emergency 

response planning. 

The early pha8e (also referred to as 

the emergency phase) is the period at 

the beginning of a nuclear incident 

when immediate decisions for effective 

use of protective actions are required 

and must therefore usually be based 

primarily on the status of the nuclear 

1-2 

facility (or other incident site) and the 

prognosis for worsening conditions. 

When available, predictions of radiological conditions in the environment 

based on the condition of the source or 

actual environmental measurements 

may also be used. Protective actions 

based. on the PAGs may be preceded by 

precautionary actions during this 

period. This phase may last from 

hours to days. 

The intermediate phase is the 

period beginning after the source and 

releases have been brought under 

control and reliable environmental 

measurements are available for use as 

a basis for decisions on additional 

. protective actions. It extends until 

these additional protective actions are 

terminated. This phase may overlap 

the early and late phase and may last 

from weeks to many months. 

The late phase (also referred to as 

the recovery phase) is the period 

beginning when recovery action 

designed to reduce radiation levels in 

the environment to acceptable levels 

for unrestricted use are commenced, 

and ending when all recovery actions 

have been completed. This period may 

..extend from months to years. 

The protective actions available to 

avoid or reduce radiation dose can be 

categorized as a function of exposure 

pathway and incident phase, as shown 

in Table 1-1. Evacuation and sheltering (supplemented by bathing and 

changes of clothing), are the principal 

protective actions for use during the 

early phase to protect the public from 

exposure to direct radiatjon and 

inhalation from. an airborne plume. It 

may·, ~so. be ;~propriate to initiate 

protective action for the milk supply 

during this period, and, in cases where 

emergency response plans include 

procedures for issuing. stable iodine to 

reduce thyroid dose (FE-85), this may 

be an appropriate protective action for 

the early phase. 

Some protective actions are not 

addressed by assignment of a PAG. 

For example, the control of access to 

areas is a protective action whose 

introduction is coupled to a decision to 

implement one of the other early or 

intermediate phase protective actions 

and does not have a separate P AG .. 

And, although the use of simple, ad hoc 

respiratory protection may be 

applicable for supplementary protection 

in some circumstances, this protective 

action is primarily for use. by 

emergency workers. 

There are two types of protective 

actions during the intermediate phase. 

First, relocation and decontamination 

are the principal protective actions for 

protec~on of the public from whole 

body external exposure · due to · 

deposited material and from inhalation 

of any resuspended radioactive 

particulate materials during the 

intermediate and late phases. It is 

assumed that decisions will be made 

during the intermediate phase 

concerning whether areas from which 

the public has. been relocated. will be 

decontaminated and reoccupied, or 

condemned and the . occupants 

permanently relocated. The second 

major type of protective action during 

the intermediate phase encompas.ses 

1-3 


I 
TABLE: 1-1 .. EXPOSURE PATHWAYS, INCIDENT PHASES, 


AND PROTECTIVE ACTIONS. 


POTENTIAL EXPOSURE PATIIWAYS 


AND INCIDENT PHASES 


1. 	 External radiation from 

facility 

2. 	 External radiation from plw:ne 

3. 	 Inhalation of activity in 

plume 

4. 	 Contamination of skin and 

clothes 

5. 	 External radiation from 

ground deposition of activity 

6. 	 Ingestion of contaminated 

food and water 

7. 	 Inhalation of resuspended 

activity 

Early 

I 

Intermediate 

I 

Late 

PROTECTIVE 


ACTIONS 


Sheltering 

Evacuation 

Conttol of access 

Sheltering 

Evacuation 

Control of access 

Sheltering 

Administration of stable iodine 

Evacuation 

Conlrol of access 

Sheltering 

Evacuation 

Decontamination of persons 

Evacuation 

Relocation 

Decontamination of land 

and property 

Food and water conttols 

Relocation 

Decontamination of land 

and property 

Note: The use of stored animal: feed and uncontaminated water to limit the uptake of radionuclides 

by domestic animals in the food chain can be applicable in any of the phases. 

1-4 

restrictions on the use of contaminated 

food and water. This protective action, 

in particular, may overlap the early 

and late phases. 

It is necessary to distinguish 

between evacuation and relocationwith 

regard to incident phases. Evacuation 

is the urgent removal ofpeople from an 

area to avoid or reduce high-level, 

short-term exposure, usually from the 

plume or. deposited activity. 

Relocation, on the other hand, is the 

removal or continued. exclusion of 

people (households) from contaminated 

areas to avoid chronic radiation 

exposure. Conditions may develop in 

which some groups who have been 

. evacuated in an emergency may be 

allowed to return based on the 

relocation P AGs, while others may be 

converted to relocation status. 

1.2 Basis for Selecting Protective 

Action Guides 

The PAGs in this manual 

incorporate the concepts and guidance 

contained in Federal Radiation Council 

(FRC) Reports 5 and 7 (FR-64 and 

FR-65). One of these is that the 

decision to implement protective 

actions should be based on the 

projected dose that would be received if 

the protective actions were not 

implemented. However, since these 

reports were issued, considerable 

additional guidance has been developed 

on the subject of emergency response 

(IC-84, IA-89). EPA considered the 

following four principles in establishing 

values for the PAGs: 

1. Acute effects on health (those that 

would be observable within a short 

period of time and- which have a dose 

threshold below which such effects are · 

not likely to occur) should be avoided. 

2. The risk of . delayed effects on 

health (primarily cancer and genetic 

effects for which linear nonthreshold 

relationships to dose are. assumed) 

should not exceed upper bounds that 

are judged to be adequately protective 

of public health under emergency 

conditions, and are reasonably 

achievable. 

3. PAGs should not be higher than 

justified on the basis of optimization of 

cost and the collective risk of effects on 

health. That is, any reduction of risk 

to public health achievable at 

acceptable cost should be carried out. 

4. Regardless of the above principles, 

the risk to health from a protective 

action should not itself exceed the risk 

to health from the dose that would be 

avoided. 

The above principles apply to the 

selection of any PAG. Principles 1, 3, 

and 4 have been proposed for use by 

the in'lernational community as 

essential bases for decisions to 

intervene during an incident and 

Principle 2 has been recognized as an 

appropriate additional consideration 

(IA-89). Appendices C and E apply 

these principles to the choice of PAGs 

for evacuation and relocation. 

Although in establishing the P AGs it is 

prudent to consider a range of source 

terms to assess the costs associated 

with their implementation, the P AGs 

1-5 

are chosen so as to be independent of 

the magnitude or type of release. 

1.3 Planning 

The planning elements for 

developing radiological emergency 

response plans for nuclear incidents at 

commercial nuclear power facilities are 

provided in a separate 4ocument, 

NUREG-0654 (NR-80), which 

references the P AGs in this Manual as 

the basis for emergency response. 

Planning elements for other types of 

nuclear incidents should be developed 

using similar types of considerations. 

Similarly, guidance for nuclear 

power facilities on time frames for 

response, the types of releases to be 

considered, emergency planning zones 

(EPZ), and the potential effectiveness 

of various protective actions is provided 

in NUREG-0396 (NR-78). The size and 

shape of the recommended EPZs were 

only partially based on consideration of 

the numerical values of the PAGs. A 

principle additional basis was that the 

planning zone for evacuation and 

sheltering should be large enough to 

accommodate any urban and rural 

areas affected and involve the various 

organizations needed for emergency 

response. This consideration is 

appropriate for any facilicy requiring 

an emergency response plan involving 

offsite areas. Experience gained 

through emergency response exercises 

is then expected to provide an adequate 

basis for expanding the response to an 

actual incident to larger areas, if 

needed. It is also noted that the 

10-mile radius EPZ for the early phase 

is large enough. to avoid exceeding the 

P AGs for the early phase at its 

boundary for low-consequence, nuclear 

reactor, core-melt accidents and to 

avoid early fatalities for 

high-consequence, nuclear reactor 

core-melt accidents. The 50-mile EPZ 

for ingestion pathways was selected to 

account for the proportionately higher 

doses via ingestion compared to 

inhalation and whole body extemal 

exposure pathways. 

1.4 Implementation of Protective 

Actions 

The sequence of events during the 

early phase indudes evaluation of 

conditions at the location of the 

incident, notification of responsible 

authorities, prediction or evaluation of 

potential consequences to the general 

public, recommendations for action, 

and implementing protection of the 

public. In the early phase of response, 

the time available to implement the 

most effective protective actions maybe 

limited. 

Immediately upon becoming aware 

that an incident has occurred that may 

result in exposure of the population, 

responsible authorities should make a 

preliminary evaluation to determine 

the nature and potential magnitude of 

the incident. This evaluation should 

determine whether conditions indi~te 

a significant possibility of a major 

release and, to the extent feasible, 

determine potential exposure 

pathways, populations at risk, and 

projected doses. The incident evaluation and recommendations should 

1-6 

then be presented to emergency 

response authorities for action. In the 

absence of recommendations for 

protective actions in specific areas from 

the official responsible for the source, 

the emergency plan should, where 

practicable, provide for protective 

action in predesignated areas. 

Contrary to the usual situation 

during the early phase, dose projections 

used to support protective action 

decisions during the intermediate and 

late phases will be based on 

measurements of environmental 

rad~oactivity and dose · models. 

Following relocation of the public from 

affected areas to protect them from 

. exposure to deposited materials, it will 

also be necessary to compile 

radiological and cost of 

decontamination data to form the basis 

for radiation protection decisions for 

recovery. 

The PAGs do not imply an 

acceptable level of risk for normal 

(nonemergency conditions). They also 

do not represent the boundary between 

safe and unsafe conditions, rather, they 

are the approximate levels at which the 

associated protective actions are 

justified. Furthermore, under emergency conditions, in addition to the 

protective actions specifically identified 

for application of PAGs, any other 

reasonable measures available should 

be taken to mrmrmze radiation 

exposure of the general public and of 

emergency workers. 

References 

FE-85 F e d e r a l E m e r g e n c y 

Management Agency. Federal Policy on 

Distribution of Potassium Iodide around 

Nuclear Power Sites for Use as a Thyroidal 

Blocking Agent. Federal Register, 50, 30256; 

July 24, 1985. 

FR-64 F e d e r a 1 R a d i a t i o n 

Council. Radiation Protection Guidance for 

Federal Agencies. Federal Register, ~ 

12056-7; August 22, 1965. 

FR-65 F e d e r a 1 R a d i a t i o n 

Council. Radiation Protection Guidance for 

Federal Agencies. Federal Register, QQ. 

6953-5; May 22, 1965. 

IA-89 I n t e r n a t i o n a 1 A t o m i c 

Energy Agency. Principles for Establishing 

Intervention Levels for the Protection of the 

Public in the Event of a Nuclear Accident or 

Radiological Emergency. Safety Series No. 

72, revision 1, International Atomic Energy 

Agency, Vienna (1991). 

IC-84 I n t e r n a t i o n a 1 

Commission on Radiological Protection. 

Protection of the Public in the Event of 

Major Radiation Accidents: Principles for 

Planning, ICRP Publication 40, Pergamon 

Press, Oxford (1984). 

NR-78 N u c l e a r R e g u l a t o r y 

Commission. Planning Basis for the 

Development ofState and Local Government 

Radiological Emergency Response Plans in 

Support of Light Water Nuclear Power 

Plants, U.S. Nuclear Regulatory 

Commission, Washington (1978). 

NR-80 N u c I e a r R e g u I a t o r y 

Commission. ·Criteria for Preparation and 

Evaluation of · Radiological Emergency 

Response Plans and Preparedness in Support 

of Nuclear Power Plants. U.S. Nuclear 

Regulatory Commission, Washington (1980). 

1-7 


CHAPTER2 

Protective Action Guides for the Early Phase 

of an Atmospheric Release 

2.1 Introduction 

Rapid action may be needed to 

protect members of the public during 

an incident involving a large release of 

radioactive materials to the 

atmosphere. This chapter identifies 

the levels of exposure to radiation at 

which such prompt protective action 

should be initiated. These are set forth 

as Protective Action Guides (PAGs) for 

the general population. Guidance for 

limiting exposure of workers during 

such an incident is also provided. This 

guidance applies to any type ofnuclear 

accident or other incident (except 

nuclear war) that can result in 

exposure of the public to an airborne 

release ofradioactive materials. 

In the case of an airborne release 

the principal relevant protective 

actions are evacuation or sheltering. 

These may be supplemented by 

additional actions such as washing and 

changing clothing or by using stable 

iodine to partially block uptake of 

radioiodine by the thyroid. 

The former Federal Radiation 

Council (FRC), in a series of 

recommendations issued in the 1960's, 

introduced the concept of PAGs and 

issued guides for avoidance ofexposure 

due to ingestion of strontium-89, 

strontium-90, cesium-137, and 

iodine-131. Those guides were 

developed for: the case of worldwide 

atmospheric , fallout from weapons 

testing, and· are appropriate for 

application to: intake due to long term 

contamination from such atmospheric 

releases. That is, they were not 

developed for protective actions 

relevant to prompt exposure to an 

airborne release from a fixed facility. 

The guidance in this chapter thus does 

not supersede this previous FRC 

guidance, but, provides new guidance 

for different ~xposure pathways and 

situations. 

2.1.1 Applicability 

These PAGs are expected to be 

used for planning purposes: for 

example, to· develop radiological 

emergency response plans and to 

exercise those plans. They provide 

guidance for :response decisions and 

should not be regarded as dose limits. 

During a real incident, because of 

characteristics ofthe incident and local 

conditions th&t cannot be anticipated, 

professional judgment will be required 

in their application. Situations could 

occur, for exatilple, in which a nuclear 

incident happ~ns when environmental 

conditions or :other constraints make 

evacuation impracticable. In these 

situations, sheltering may be the 

2-1 

protective action of choice, even at 

projected doses above the P AG for 

evacuation. Conversely, in some cases 

evacuation may be useful at projected 

doses below the P AGs. Each case will 

require judgments by those responsible 

for decisions on protective actions at 

the time of an incident. 

The P AGs are intended for general 

use to protect all of the individuals in 

an exposed population. To avoid social 

and family disruption and the 

complexity of implementing different 

P AGs for different groups under 

emergency conditions, the P AGs should 

be applied equally to most members of 

the population. However, there are 

some population groups that are at 

markedly different levels of risk from 

some protective actions -- particularly 

evacuation. Evacuation at higher 

values is appropriate for a few groups 

for whom the risk associated with 

evacuation is exceptionally high (e.g., 

the infirm who are not readily mobile), 

and the PAGs provide for this. 

Some incidents may occur under 

circumstances in which · protective 

actions cannot be implemented prior to 

a release (e.g., transportation 

incidents). Other incidents may 

involve only slow, small releases over 

an extended period, so that the urgency 

is reduced and protective action may be 

more appropriately treated as 

relocation (see Chapter 4) than as 

evacuation. Careful judgment will be 

needed to decide whether or not to 

apply these P AGs for the early phase 

under such circumstances. 

The PAGs do not imply an 

acceptable level of risk for normal 

(nonemergency) conditions. PAGs also 

do not represent the boundary between 

safe and unsafe conditions; rather, they 

are the approximate levels at which the 

associated protective actions are 

justified. Furthermore, under 

emergency conditions, in addition to 

the protective actions specifically 

identified, any other reasonable 

measures available! should be taken to 

reduce radiation exposure of the 

general public and of emergency 

workers. These P AGs are not intended 

for use as criteria for the ingestion of 

contaminated food or water, for 

relocation, or for retum to an area 

contaminated by radioactivity. 

Separate guidance is provided for these 

situations in Chapters 3 and 4. 

2.1.2 Emergency Planning Zones and 

the PAGs 

For the purpose of identifying the 

size of the planning area needed .to 

establish and test radiological 

emergency response plans, emergency 

planning zones (EPZs) are typically 

specified around nuclear facilities. 

There has been some confusion among 

emergency planners between these 

EPZs and the areas potentially affected 

by protective actions. It is not 

appropriate to use the maximum 

distance where a PAG might be 

exceeded as the basis for establishing 

the boundary of the EPZ for a facility. 

For example, the choice of EPZs for 

commercial nuclear power facilities has 

been based, primarily, on consideration 

of the area needed to assure an 

2-2 

adequate planning · basis for local 

response functions and the area in 

which acute health effects could occur.1 

These considerations will also be 

appropriate for use in selecting EPZs 

for .most other nuclear facilities. 

However, since it will usually not be 

necessary to have offsite planning if 

P AGs cannot be exceeded offsite, EPZs 

need not be established for such cases. 

2.1.3 Incident Phase 

The period addressed by this 

chapter is denoted the "early phase." 

This is somewhat arbitrarily defined as 

the period beginning at the projected 

(or actual) initiation of a release and 

extending to a few days later, when 

deposition of airborne materials has 

ceased and enough information has 

become available to permit reliable 

decisions about the need for longer 

term protection. During the early 

phase of an incident doses may accrue 

both from airborne and from deposited 

radioactive materials. Since the dose 

to persons who are not evacuated will 

continue until relocation can be 

implemented (if it is necessary), it is 

appropriate to include in the early 

1

The development of EPZs for nuclear power 

facilities is discussed in the 1978 NRC/EPA 

document "Planning Basis for the Development 

of State and Local Government Radiological 

Emergency Response Plans in Support ofLight 

Water Nuclear Power Plants" NUREG-0396. 

EPZs for these facilities have typically been 

chosen to have a radius of approximately 10 

miles for planning evacuation and sheltering 

and a radius of approximately 50 miles for 

planning protection from ingestion of 

contaminated foods. 

phase the total dose that will be 

received prior! to such relocation. For 

the purpose of planning, it will usually 

be convenient to assume that the early 

phase will last for four days -- that is, 

that the duration of the primary 

release is less :than four days, and that 

exposure to deposited materials after 

four days cari be addressed through 

other protective actions, such as 

relocation, if this is warranted. 

(Because of the unique characteristics 

ofsome facilities or situations, different 

time periods may be more appropriate 

for planni:hg purposes, with 

corresponding. modification of the dose 

conversion factors cited in Chapter 5.) 

2.2 Exposure Pathways 

The PAGs for members of the 

public specified in this chapter refer 

only to doses incurred during the early 

phase. These may include external 

gamma dose and beta dose to the skin 

from direct ·exposure to airborne 

materials and from deposited 

materials, and the committed dose to 

internal organs from inhalation of 

radioactive material. Exposure 

pathways th~t make only a small 

contribution (e.g., less than about 10 

percent) to the dose incurred in the 

early phase need not be considered. 

Inhalation of resuspended particulate 

materials will~ for example, generally 

fall into this category. 

Individuals exposed to a plume 

may also be. exposed to deposited 

material over longer periods oftime via 

ingestion, direct external exposure, and 

inhalation pathways. Because it is 

2-3 

usually not practicable, at the time of 

an incident, to project these long-term 

doses and because different protective 

actions maybe appropriate, these doses 

are not included in the dose specified 

in the P AGs for the early phase. Such 

doses are addressed by the PAGs for 

the intermediate phase (see Chapters 3 

and4). 

The first exposure pathway from 

an accidental airborne release of 

radioactive material will often be direct 

exposure to an overhead plume of 

radioactive material carried by winds. 

The detailed content of such a plume 

·will depend on the source involved and 

conditions of the incident. For 

example, in the case of an incident at a 

nuclear power reactor, it would most 

commonly contain radioactive noble 

gases, but may also contain 

radioiodines and radioactive particulate 

materials. Many ofthe these materials 

emit gamma radiation which can 

expose people nearby, as the plume 

passes. In the case ofsome other types 

of incidents, particularly those 

involving releases of alpha emitting 

particulate materials, direct exposure 

to gamma radiation is not likely to be 

the most important pathway. · 

A second exposure pathway occurs 

when people are directly immersed in a 

radioactive plume, in which case 

radioactivematerial is inhaled (and the 

skin and clothes may also become 

contaminated), e.g., when particulate 

materials or radioiodines are present. 

When this occurs, internal body organs 

as well as the skin may be exposed. 

Although exposure from materials 

deposited on the skin and clothing 

could be significant, generally it will be 

less important than that from 

radioactive material taken into the 

body through inhalation. This is 

especially true if early protective 

actions include washing exposed skin 

and changing clothing. Inhaled 

radioactive particulate materials, 

depending on their solubility in body 

fluids, may remain in the lungs or 

move via the bloodstream to other 

organs, prior to elimination from the 

body. Some radionuclides, once in the 

bloodstream, are concentrated in a 

single body organ, with only small 

amounts going to other organs. For 

example, if radioiodines are inhaled, a 

significant fraction moves rapidly 

through the bloodstream to the thyroid 

gland. 

As the passage of a radioactive 

plume containing particulate material 

and/or radioiodine progresses, some of 

these materials will deposit onto the 

ground and other surfaces and create a 

third exposure pathway. People 

present after the plume has passed will 

receive exposure from gamma and beta 

radiation emitted from these deposited 

materials. If large quantities · of 

radioiodines or gamma-emitting 

particulate materials are contained :in 

a release, this exp1osure pathway, o~er 

a long period, can be more signific~nt 

than direct exposure to gamma 

radiation from the passing plume. 

2.3 The Protective Action Guides 

The PAGs for response during the 

early phase of an incident are 

summarized in Table 2-1. The PAG for 

2-4 

evacuation (or, as an alternative in 

certain cases, sheltering) is expressed 

in terms of the projected sum of the 

effective dose equivalent from external 

radiation and the committed effective 

dose equivalent incurred from 

inhalation ofradioactive materials from 

exposure and intake during the early 

phase. (Further references to dose to 

members of the public in this Chapter 

refer to this definition, unless 

otherwise specified.) Supplementary 

· guides are specified in terms of 

committed dose equivalent to the 

thyroid and dose equivalent to the skin. 

The P AG for the administration of 

stable iodine is specified in terms ofthe 

committed dose equivalent to the 

thyroid from radioiodine. This more 

complete guidance updates and 

replaces previous values, expressed in 

terms of whole-body dose equivalent 

from external gamma exposure and 

thyroid dose equivalentfrom inhalation 

of radioactive iodines, that were 

recommended in the 1980 edition of 

this document. 

2.3.1 EYacuation and Sheltering 

The basis for the PAGs is given in 

Appendix C. In summary, this analysis 

indicates that evacuation of the public 

will usually be justified when the 

projected dose to an individual is one 

rem. This conclusion is based primarily on EPA's judgment concerning 

acceptable levels of risk of effects on 

public health from radiation exposure 

in an emergency situation. The 

analysis also shows that, at this 

radiation dose, the risk avoided is 

usually much greater than the risk 

from evacuation itself. However, EPA 

recognizes the; uncertainties associated 

with quantifying risks associated with 

these levels of radiation exposure, as 

well as the variability of risks 

associated With evacuation under 

differing conditions. 

Some judgment will be necessary 

when considering the types of 

protective actions to be implemented 

and at what levels in an emergency 

situation. Although the PAG is 

expressed as a range of 1-5 rem, it is 

emphasized 'that, under normal 

conditions, evacuation of members of 

the general · population should be 

initiated for most incidents at a 

projected dose of 1 rem. (It should be 

recognized that doses to some 

individuals may exceed 1 rem, even if 

protective acti,ons are initiated within 

this guidance.) It is also possible that 

conditions niay exist at specific 

facilities which warrant consideration 

of values other than those recommended for general use here.3 

Sheltering may be preferable to 

evacuation as a protective action in 

some situations. Because ofthe higher 

risk associateq with evacuation ofsome 

special groups in the population (e.g. 

those who are not readily mobile), 

sheltering may be the preferred 

alternative for such groups as a 

3

EPA, in accordance with its responsibilities 

under the regulations governing radiological 

emergency planning (47FR10758; March 11, 

1982) and under the Federal Radiological 

Emergency Response Plan, will consult with 

Federal agencies and the States, as requested, 

in such cases. 

2-5 

Table 2-1 PAGs for the Early Phase of a Nuclear Incident 

Protective PAG Comments 

Action ·(projected dose) 

Evacuation 1-5 remb Evacuation (or, for some 

(or shelterin~) situations, shelterin~) 

should normally be 

initiated at 1 rem. 

Further guidance is 

provided in Section 2.3.1 

Administration of Requires approval of 

stable iodine State medical officials; 

•sheltering may be the preferred protective action when it will provide protection equal to or 

greater than evacuation, based on consideration of factors such as source term characteristics, and 

temporal or other site-specific conditions (see Section 2.3.1). 

arhe sum of the effective dose equivalent resulting from exposure to external sources and the 

committed effective dose equivalent incurred from all significant inhalation pathways during the 

early phase. Committed dose equivalents to the thyroid and to the skin may be 5 and 50 times 

larger, respectively. 

ccommitted dose equivalent to the thyroid from radioiodine. 

protective action at projected doses up conditions. illustrative examples of 

to 5 rem. In addition, under unusually situations or groups for which 

hazardous environmental conditions evacuation may not be appropriate at 1 

use of sheltering at projected doses up rem include: a) the presence of severe 

to 5 rem to the general population (and weather, b) competing disasters, c) 

up to 10 rem to special groups) may institutionalized persons who are not 

become justified. Sheltering may also readily mobile, and d) local physical 

provide protection equal to or greater factors which impede evacuation. 

than evacuation due to the nature of Examples of situations or groups for 

the source term and/or in the presence which evacuation at 1 rem normally 

of temporal or other site-specific would be appropriate include: a) an 

2-6 

incident which occurs at night, b) an 

incident which occurs when children 

are in school, and c) institutionalized 

persons who are readily mobile. 

Evacuation seldom will be justified at 

less than 1 rem. The examples 

described above regarding selection of 

the most appropriate protective action 

are intended to be illustrative and not 

exhaustive. In general, sheltering 

should be preferred to evacuation 

whenever it provides equal or greater 

protection. 

No specific rmmmum level is 

established for initiation of sheltering. 

Sheltering in place is a low-cost, 

low-risk protective action that can 

provide protection with an efficiency 

ranging from zero to almost 100 

percent, depending on the circumstances. It can also be particularly 

useful to assure that a population is 

positioned so that, if the need arises, 

communication with the population can 

be carried out expeditiously. For the 

above reasons, planners and decision 

makers should consider implementing 

sheltering at projected doses below 1 

rem; however, implementing protective 

actions for projected doses at very low 

levels would not be reasonable (e.g. 

below 0.1 rem). (This guidance should 

not be construed as establishing an 

additional lower level PAG for 

sheltering.) Sheltering should always 

be implemented in cases when 

evacuation is not carried out at 

projected doses of 1 rem or more. 

Analyses for some hypothesized 

accidents, such as short-term releases 

of transuranic materials, show that 

sheltering in residences and other 

buildings can be highly effective at 

reducing dose~ may provide adequate 

protection, and may be more effective 

than evacuation when evacuation I 

cannot be completed before plume 

arrival (D0-90). However, reliance on 

large dose .reduction factors for 

sheltering should be accompanied by 

cautious examination ofpossible failure 

mechanisms, · and, except in very 

unusual circun1stances, should never be 

relied upon at projected doses greater 

than 10 rem. Such analyses should be 

based on realistic or "best estimate" 

dose models and include unavoidable 

dose during ev1;1cuation. Shelteringand 

evacuation are discussed in more detail 

in Section 5.5. 

2.3.2 Thyroid and Skin Protection 

Since the thyroid is at 

disproportionately high risk for 

induction of nonfatal cancer and 

nodules, compared to other intemal 

organs, additional guidance is provided 

to limit the risk of these effects (see 

footnote to Table 2-1). In addition, 

effective dose, the quantity used to 

express the PAG, encompasses only the 

risk of fatal cancer from irradiation of 

organs within the body, and does not 

include dose to skin. Guidance is also 

provided, therefore, to protect against 

the risk of skin cancer (see Table 2-1, 

footnote b). 

The use of stable iodine to protect 

against uptak~ of inhaled radioiodine 

by the thyroid is recognized as an 

effective alternative to evacuation for 

situations i:hvolving radioiodine 

releases when. evacuation cannot be 

2-7 

implemented or exposure occurs dUring 

evacuation. Stable iodine is most 

effective when administered 

immediately prior to exposure to 

radioiodine. However, significant 

blockage of the thyroid dose can be 

provided by administration within one 

or two hours after uptake of radioiodine. Ifthe administration of stable 

iodine is included in an emergency 

response plan, its use may be 

considered for exposure situations in 

which the committed dose equivalent to 

the thyroid can be 25 rem or greater 

(see 47 FR 28158; June 29, 1982). 

Washing and changing of clothing 

is recommended primarily to provide 

protection from beta radiation from 

radioiodines and particulate materials 

deposited on the skin or clothing. 

Calculations indicate that dose to skin 

should seldom, if ever, be a controlling 

pathway. However, itis good radiation 

protection practice to recommend these 

actions, even for alpha-emitting 

radioactive materials, as soon as 

practical for persons significantly 

exposed to a contaminating plume (i.e., 

when the projected dose from inhalation would have justified evacuation of 

the public under normal conditions). 

2.4 Dose Projection 

The PAGs are expressed in terms 

of projected dose. However, in the 

early phase of an incident (either at a 

nuclear facility or other accident site), 

parameters other than projected dose 

may frequently provide a more 

appropriate basis for decisions to 

implement protective actions. When a 

facility is operating outside its design 

basis, or an incident is imminent but 

has not yet occurred, data adequate to 

directly estimate the projected dose 

may not be available. For such cases, 

provision should lbe made during the 

planning stage for decisions to be made 

based on specific conditions at the 

source of a possible release that are 

relatable to ranges of anticipated 

offsite consequences. En1ergency 

response plans for facilities should 

Dlake use of E01ergency Action Lev,els 

(EALs)4

, based on in-plant conditions, 

to trigger notification of and 

recommendations to offsite officials to 

implement prompt evacuation or 

sheltering in specified areas in the 

absence of inforn1ation on actual 

releases or environmental 

01easurements. Later, when these data 

becoDle available, dose projections 

based on measurements 01ay be used, 

in addition to plant conditions, as the 

basis for iDlplementing further 

protective actions. (Exceptions may 

occur at sites with large exclusion 

areas where some field and source data 

may be available in sufficient ti01e for 

protective action decisions to be ba:sed 

on environ01entaJ. measurements.) In 

the case of transportation accidents or 

other incidents. that are not related to 

a facility, it will often not . be 

practicable to establish EALs. 

The calculation of projected doses 

should be based on realistic dose 

~mergency Action Levels related to plant 

conditions at commercial nuclear power plants 

are discussed in Appendix 1 to NUREG-0654 

(NR-80). 

2-8 

models, to the extent practicable. 

Doses incurred prior to initiation of a 

protective action should not normally 

be included. Similarly, doses that 

might be received following the early 

phase should not be included for 

decisions on whether or not to evacuate 

or shelter. Such doses, which may 

occur from food and water, long-term 

radiation exposure to deposited 

radioactive materials, or long-term 

inhalation of resuspended materials, 

are chronic exposures for which neither 

emergency evacuation nor sheltering 

are appropriate protective actions. 

Separate P AGs relate the ~ppropriate 

protective action decisions to those 

exposure pathways (Chapter 4). As 

noted earlier, the projection of doses in 

the early phase need include only those 

exposure pathways that contribute a 

significant fraction (e.g., more than 

about 10 percent) of the dose to an 

individual. 

In practical applications, dose 

projection will usually begin at the 

time of the anticipated (or actual) 

initiation of a release. For those 

situations where significant dose has 

already occurred prior to implementing 

protective action, the projected dose for 

comparison to a PAG should not 

include this prior dose. 

2.5 Guidance for Controlling Doses to 

Workers Under Emergency Conditions 

The P AGs for protection of the 

general population and dose limits for 

workers performing emergency services 

are derived under different 

assumptions. P AGs consider the risks 

to individuals, themselves, from 

exposure to radiation, and the risks 

and costs associated with a specific 

protective action. On the other hand, 

workers may jl"eceive exposure under a 

variety of circumstances in order to 

assure proteCtion of others and of 

valuable property. These exposures 

will be justified if the maximum risks 

permitted to . workers are acceptably 

low, and the •risks or costs to others 

that are avoided by their actions 

outweigh the· risks to which workers 

are subjected.. 

' Workers who may incur increased 

levels of exposure under emergency 

conditions may include those employed 

in law enforcement, fire fighting~ 

radiation protection, civil defense, 

traffic control, health services, 

environmental monitoring, transportation services, and animal care. In 

addition, selected workers at 

institutional, ' utility, and industrial 

facilities, and at farms and other 

agribusiness may be required to protect 

others, or to protect valuable property 

during an emergency. The above are 

examples - :not designations - of 

workers that may be exposed to 

radiation under emergency conditions. 

Guidance. on dose limits for 

workers performing emergency services 

is summarized in Table 2-2. These 

limits apply to doses incurred over the 

duration of an emergency. That is, in 

contrast to the PAGs, where only the 

future dose that can be avoided by a 

specific prote(ftive action is considered, 

all doses received during an emergency 

are included in the limit. Further, the 

dose to workers performing emergency 

2-9 

Table 2-2 Guidance on Dose Limits for Workers Performing Emergency Services 

Dose limita 

(rem) 

Activity Condition 

5 all 

10 ,protecting valuable 

property 

lower dose not practicable 

25 life saving or 

protection of large 

.populations 

lower dose not practicable 

>25 lifesaving or 

protection of large 

populations 

only on a voluntary basis 

to persons fully aware of 

the risks involved (See 

Tables 2-3 and 2-4) 

aSum of external effective dose equivalent and committed effective dose equivalent to nonpregnant 

adults from exposure and intake during an emergency situation. Workers performing services during 

emergencies should limit dose to the lens of the eye to three times the listed value and doses to any 

other organ (including skin and body extremities) to ten times the listed value. These limits apply to 

all doses from an incident, except those received in unrestricted areas as members of the public during 

the intermediate phase of the incident (see Chapters 3 and 4). 

services may be treated as a once-in-alifetime exposure, and not added to 

occupational exposure accumulated 

under nonemergency conditions for the 

purpose ofascertaining conformance to 

normal occupational limits, if this is 

necessary. However, any radiation 

exposure of workers that is associated 

with an incident, but accrued during 

nonemergency operations, should be 

limited in accordance with relevant 

occupational limits for normal 

situations. Federal Radiation 

Protection Guidance for occupational 

exposure recommends an upper bound 

of five rem per year for adults and one 

tenth this value for minors and the 

unborn (EP-87). We recommend use of 

this same value here for the case of 

exposures during an emergency. To 

assure adequate protection of minors 

and the unborn during emergencies, 

the performance of emergency services 

should be limited to nonpregnant 

adults. As in the case of normal 

occupational exposure, doses received 

under emergency conditions should also 

be maintained as low as reasonably 

achievable (e.g., use of stable iodine, 

where appropriate, as a prophylaxis to 

2-10 

reduce thyroid dose from inhalation of 

radioiodines and use of rotation of 

workers). 

Doses to all workers during 

emergencies should, to the extent 

practicable, be limited to 5 rem. There 

are some emergency situations, 

however, for which higher exposure 

limits may be justified. Justification of 

any such exposure must include the 

presence of conditions that prevent the 

rotation of workers or other 

commonly-used dose reduction 

methods. Except as noted below, the 

dose resulting from such emergency 

exposure should be limited to 10 rem 

for protecting valuable property, and to 

25 rem for life saving activities and the 

protection oflarge populations. In the 

context of this guidance, exposure of 

workers that is incurred for the 

protection oflarge populations may be 

considered justified for situations in 

which the collective dose avoided by 

the emergency operation is significantly larger than that incurred by the 

workers involved. 

Situations may also rarely occur in 

which a dose in excess of 25 rem for 

emergency exposure would be 

unavoidable in order to carry out a 

lifesaving operation or to avoid 

extensive exposure oflarge populations. 

It is not possible to prejudge the risk 

that one should be allowed to take to 

save the lives of others. However, 

persons undertaking any emergency 

operation in which the dose will exceed 

25 rem to the whole body should do so 

only on a voluntary basis and with full 

awareness of the risks involved, 

including the numerical levels of dose 

at which acute effects of radiation will 

be incurred and numerical estimates of 

·the risk of delayed effects. 

Tables 2-3 and 2-4 provide some 

general information that may be useful 

in advising emergency workers ofrisks 

of acute and delayed health effects 

associated with large doses of radiation. Table 2-3 presents estimated 

risks of early fatalities and moderately 

severe prodromal (forewarning) effects 

that are lik~ly to occur shortly after 

exposure to awide range ofwhole body 

radiation doses. Estimated average 

cancer mortality risks for emergency 

workers corr(asponding to a whole-body 

dose equivalent of 25 rem are given in 

Table 2-4, as a function of age at the 

time of exposure. To estimate average 

cancer mortaHty for moderately higher 

doses the re~ults in Table 2-4 may be 

increased linearly. These values were 

calculated using a life table analysis 

that assumes the period of risk 

continues for ·the duration of the 

worker's lifetime. Somewhat smaller 

risks of serious genetic effects (if 

gonadal tissue is exposed) and of 

nonfatal cancer would also be incurred. 

An expanded discussion of health 

effects from tadiation dose is provided 

in Appendix B. 

Some 'workers performing 

emergency services will have little or 

no health physics training, so dose 

minimization through use of protective 

equipment cannot always be assumed. 

However, the use of respiratory 

protective equipment can reduce dose 

from inhalation, and clothing can 

reduce beta dose. Stable iodine is also 

recommended for blocking thyroid 

2-11 

Table 2-3 Health Effects Associated with Whole-Body Absorbed Doses Received· 

Within a Few Hoursa (see Appendix B) 

Whole Body Early Whole Body 

Absorbed dose Fatalitiesb Absorbed dose 

(rad) (percent) (rad) 

140 5 50 

200 15 100 

300 50 150 

400 85 200 

460 95 250 

•rusks will be lower for protracted exposure periods. 

' 

bSupportive medical treatment may increase the dose at which 

these frequencies occur by approximately 50 percent. 

~orewarning symptoms ofmore serious health effects associated 

with large doses of radiation. 

Prodromal Effectsc 

(percent affected) 

2 

15 

50 

85 

98 

Table 2-4 Approximate Cancer Risk to Average Individuals from 25 Rem Effective 

Dose Equivalent Delivered Promptly (see Appendix C) 

Age at 

exposure 

(years) 

20 to 30 

30 to 40 

40 to 50 

50 to 60 

Appropriate risk 

of premature death 

(deaths per 1,000 

persons exposed) 

9.1 

7.2 

5.3 

3.5 

Average years of 


life lost if premature 


death occurs 


(years) 


24 

19 

15 

11 

~2-12 
uptake of radioiodine in personnel 

involved in emergency actions where 

atmospheric releases include 

radioiodine. The decision to issue 

stable iodine should include 

consideration of established State 

medical procedures, and planning is 

required to ensure its availability and 

proper use. 

References 

D0-90 U.S. n:epartment of Energy. 

Effectiveness of Sheltering in Buildings and 

Vehicles for Plutonium, DOE/EH-0159, U.S. 

Department of Energy, Washington (1990). 

EP-87 U.S. Environmental Protection Agency. 

Radiation Protection Guidance to Federal 

Agencies for Occupational Exposure. Federal 

Register,~ 2822; January 27, 1987. 

NR-80 U.S. Nuclear Regulatory Commission. 

Criteria for Preparation and Evaluation of 

Radiological Emergency Response Plans and 

Preparedness hl Support of Nuclear Power 

Plants. NUREG-0654, U.S. Nuclear 

Regulatory Commission, Washington, (1980). 

2-13 


CHAPTERS 

Protective Action Guides for the Intermediate Phase 

(Food and Water) 

a) Accidental Radioactive Contamination of Human Food and Animal Feeds; 

Recommendations for State and Local Agencies* · 

b) Drinking Water** 

"' These recommendations were published by FDA in 1982. 

**Protective action recommendations for drinking water are under development by 

EPA. 

3-1 


Federal Register I Vol. 47, No. 205 / Friday, October 22.! 1982 / Notices 47073 

DEPARTMENT OF HEALTH AND 

HUM~N SERVICES 

.Food and Drug Administration 

,£Docket No. 78N-oGSOJ 

Accidental Radioactive COnt8tinMion 

of Human Food and Animal Feed8; 

!Recommendatlon8 for State and· Local 

Agencies 

·AGENCY: Food and Drug Admihistration. 


ACTION: Notice. 


' 


SUMMARY: The Food and Drug 

;Administration (FDA) is publishing this 

notice to provide to State and local 

agencies responsible for emergency 

'response planning for radiological 

incidents recommendations for taking 

protective actions in the event that an 

incident causes the contamination of 

human food or animal feeds. These 

:recommendations can be used to 

determine whether levels ofradiation 

encountered in food after a radiological 

·incident warrant protective action and 

'to suggest appropriate actions that may 

be taken if action is warranted. FDA has 

a responsibility to issue guidanc~ on 
47074 Federal Register I Vol. 47, No. 205 I Fl"ic:.iay, October 22, 1982 I Notices

- appropriate planning actions necessary 

for evaluating and preventing 

contamination of human food and 

animal feeds and on the control and use 

of these products should they become 

contaminated. 

FOR FURTHER INFORMATION CONTACT: 

Gail D. Schmidt, Bureau of Radiologic.• I 

Health (HFX-1), Food and Drug 

Administration, 5600 Fishers Lane, 

Rockville, MD 20857, 301-443-2650. 

!;UPPLEMENTARV INFORMATION: 

Background 

This guidance on accidental 

radioactive contamination of food from 

fixed nuclear facilities, transportation 

accidents, and fa!Iout is part of a 

Federal interagency effort coordinated 

by the Federal Emergency Management 

Agency (FEMA). FEMA issued a final 

regulation in the Federal Register of 

March 11, 1982 (47 FR 10758), which 

reflected governmental reorganizations 

and reassigned agency responsibilities 

for radiological incident emergency 

response planning. A responsibility 

assigned to the Department of Health 

and Human Services (HHS) (and in turn 

delegated to FDA) is the responsibility 

to develop and specify to State and local 

governments protective actions and 

associated guidance for human food and 

animal feed. 

In the Federal Register of December 

15, 1978 (43 FR 58790), FDA published 

proposed recommendations for State 

and local agencies regarding accidental 

radioactive contamination of human 

food and animal feeds. Interested 

persons were given until February 13, 

1979 to comment on the proposal. 

Twenty-one comments were received 

from State agencies, Federal agencies, 

nuclear utilities, and others. Two of the 

comments from environmentally 

concerned organizations were received 

after the March 28, 1979 accident at 

Three Mile Island, which increased 

public awareness of protective action 

guidance. Although these comments 

were received after the close of the 

comment period, they were COIJ.Sidered 

by the agency in developing these final 

recommendations. · The Office of Radiation Programs, 

Environmental Protection Agency (EPA), 

submitted a detailed and exhaustive 

critique o£ the proposed 

recommendations. EPA addressed the 

dosimetry data, the agricultural models 

used in calculating the derived response 

levels, and the philosophical basis for 

establishing the numerical value of the 

protective action guides. FDA advises 

that, to be responsive to the EPA 

comments, FDA staff met with staff of 

the Office of Radiation Programs. EPA. 

during the dcvelopnwnt of these final 

recommendations. Although EPA's 

formal comments are responded to in 

this notice, EPA staff reviewed a draft of 

the final recommendations, and FDA 

has considered their additional informal 

comments. These contacts were 

considered appropriate because EPA 

has indicated that it inter:ds to use the 

recommendations as the basis for 

revising its guidance to Federal agencies 

on protective action guides for 

radioactivity in food. 

Protective Action Guidance 

Although not raised in the comments 

received, .FDA has reconsidered its 

proposal to codify these 

recommendations in 21 CFR Part 1090. 

Because these recommendations are 

voluntary guidance to Stale and local 

agencies (not regulations). FDA has 

decided not to codify the 

recummendations; rather, it is issuing 

them in this notice. Elsewhere in this 

issue of the Federal Register, FDA is 

withdrawing the December 15, 1978 

proposal. 

The recommendations tontain basic 

criteria, defined as proteative action 

guides (PAG's), for establishing the level 

of radioactive contamination of human 

food or animal feeds at which action 

should be taken to protect the public 

health and assure the safety of food. The 

recommendations also contain specific 

guidance on what emergency protective 

actions should be taken to prevent 

further contamination of food or feeds or 

to restrict the use of food, as well as 

more general guidance on the 

development and implementation of 

emergency ._!:lion. The PAG's have been 

developed on the basis of 

considerations of acceptable risk to 

identify that level of contamination at 

which action is necessary to protect the 

public health. 

In preparing these recommendations, 

FDA has reviewed and utilized the 

Federal guidance on protective actions 

contained in Federal Radiati-on Council 

(fflC) Reports No.5, July 1964 (Ref. 1) 

and No. 7, May 1965 (Ref. 2). The 

Federal guidance provides that each 

Federal agency, by virtue of its 

immediate knowledge or its operating 

problems, would use the applicable FRC 

guides as a basis for developing detailed 

standards to meet the particular needs 

of the agency. FDA's recommendations 

incorporate the FRC concepts and the 

FRC guidance that protective actions, in 

the event of a contaminating accident, 

should be based on estimates of the 

projected radiation dose that would be 

received in the absence of taking 

protective actions. Similarly, protective 

actions should be implemented for a 

sufficient time to avoid most of the 

projected radiation dose. Thus, the 

P.'\G's define the numerical vahJe of 

projected radiation doses for which 

protective actions are recommended. 

FDA has reviewed the recent report of 

the National Academy of Sciences/ 

National Research Council (Ref. 3) on 

radiation risks and biological effects 

data that became available after 

publiculinn of the FRC guidance and has 

reviewed the impact of taking action in 

the pasture/cow/milk/person pathway 

in light of the current concerns in 

rucliation protection. Based on these 

considerations and the comments 

rl!ccived on the proposed 

recommendations, FDA has concluded 

that protective actions of ldw impact 

should he undertaken at projecte~ 

radiation doses lower than those 

recommended by FRC (Refs. 1 a"ld 2). 

Accordingly, FDA is recommending lowimpact protective actions (termed the 

Preventive PAG) at projected radiation 

doses of 0.5 rem whole body and 1.5 rem 

thyroid. FDA intends that such 

protective actions be implemented to 

prevent the appearance of radioactivity 

in food at levels that. would require its 

condemnation. Preventive PAG's 

include the transfer of dairy cows from 

fresh forage (pasture) to uncontaminated 

stored feed and the diversion of whole 

milk potentially contaminated with 

short-lived radionuclides to products 

with a long shelf life to allow 

radioactive decay of the radioactive 

material. 

In those situations where the. only 

protective actions that are feasible 

present high dietary and social costs or 

impacts (termed the Emergency PAG) 

action is recommended at projected 

radiation doses of 5 rem whole body 

and 15 rem thyroid. At the Emergency 

PAG level responsible officials should 

isolate food to prevent its introduction 

into commerce and determine whether 

condemnation or other disposition is 

appropriate. Action at the Emergency 

PAG level is most likely for the 

population that is near to the source of 

radioactive contamination and that 

consumes home-grown produce and 

milk. 

The PAG's represent FDA's judgment 

as to that level of food contamination 

resulting from radiation incidents at 

which action should be taken to protect 

the public health. This is based on the 

agency's recognition that safety involves 

the degree to which risks are judged 

acceptable. The risk from natural 

disasters (approximately a one in a 

million annual individual risk of death) 

and the risk from variations in natural 

bac:kground radiation have provided 
FedeT~l Register 4707.5 / Vol. 47, No. 205 I Friday, October 22, l982j Notices 

perspective in selecting the PAG values. 

This issue is further discussed in the 

responses to specific comments later in 

this notice, especially in paragraph 9. A more detailed treatment of the rationale, 

risk factors, dosimetric and agricultural 

models, and methods of calculation is 

contained in the "Background for 

Protective Action Recommendations: 

Accidental Radioactive Contamination 

of Food and Animal Feeds" (Ref. 22). 

Organ PAG Values 

' . 

Current scientific evidence. as reflected by BEIR-1 (Ref. 18), 

UNSCEAR-1977 (Ref. 8}. ami BEIR-lll 

(Ref. 3), indicates that the relative 

importance of risk due to specific organ 

exposure is quite different from the 

earlier assumptions. The International 

Commission on Radiological Protection 

(ICRP) clearly recognized this in its 1977 

recommendations (ICRP-26 (Ref. 6)), 

which changed the metl_lodology for 

treating external and internal radiation 

doses and the relative importance of 

specifw organ doses. ICRP-26 assigned 

weighting factors to specific organs 

based on considerations of the 

incidence and severity (mortality} of 

radiation cancer induction. For the 

radionuclides of concern for food PAG's, 

ICRP-26 assigned weighting factors of 

0.03 for the thyroid and 0.12 for red bone 

marrow. Thus, the organ doses equal in 

risk to 1 rem whole body radiation dose are 33 rem to the thyroid and 8 rem to 

Red bone marrow. (The additional ICRP-26~ nonstocbastic limit, however, 

restricts the thyroid dose to 50 rem or 10 

times the whole body occupational limit 

of 5 rem.) 

In the Federal Register of January 23, 

1981 (46 FR 7836), EPA proposed to 

revise the Federal Radiation Protection 

Guidance for Occupational Exposures 

using the ICRP approach for internal 

organ radiation doses, modified to 

reflect specific EPA concerns. The EPA 

proposal has been subject to 

considerable controversy. Also. the 

National Council on Radiation 

Protection and Measurements (NCRP} 

curently is evaluating the need to revise 

its recommendations. FDA does not, 

·however, expect the protection model 

for internal organ radiation doses to be 

resolved rapidly in the United States 

and has based the relative PAG dose 

assignments in these re·commendations on current U.S. standards and the 1971 

recommendations in NCRP-39 (Ref. 19). 

Thus. the red bone marrow is assigned 

the same PAG dose as the whole body 

(0.5 rem Preventive PAG). and the 

thyroid PAG is greater by a factor of 

three (1.5 rem Preventive PAG}. This 

results in PAG assignments for the 

thyroid and red bone marrow that are 

lower by factors of 3.3 and a; 

respectively, than values based on ICRP-26 (Ref. 6}. FDA adVises that it 

will make appropriate changes in 

recommendations for internal organ 

doses when a consensus in the United 

Slates emerges. 

Analysis of Comments 

The following is a summary of the 

comments received on the December 15, 

1978 proposal and the agency's response 

to them: 

1. Several comments requested 

clarification of the applicability and 

compatibility of FDA's 

recommendations with other Federal 

actions, specifically the PAG guidance 

of EPA (Ref. 7), the FRC Reports No. 5 

(Ref. 1) and No. 7 (Ref. 2), and the 

Nuclear Regulatory Commission (NRC) 

definition of "Extraordinary Nuclear 

Occurrence" in 10 CFR Part 140. A 

comment recommended that the term, 

"Protective Action Guide (PAG)", not be 

used because that term traditionally has 

been associated with the FRC, and the 

general public would confuse FDA's 

recommendations with Federal 

guidance. 

The FRC Report No. 5 specifically 

recommended that the term, "protective 

action guide," be adopted for Federal use. The report defines the term as the 

"projected absorbed dose to the 

individuals in the general population 

which warrants protective action 

following a contaminating event," a 

concept that is addressed by FDA's 

recommendations. To use the concept 

with a different description would, in 

FDA's opinion, be unnecessarily 

confusing to State and local agencies as well as Federal agencies. 

These recommendations are being 

issued to fulfill the HHS responsibilities 

under FEMA's March 11, 1982 

regulation. FDA fully considered FRC 

Reports No. 5 and No. 7 and the basic 

concepts and philosophy of the FRC 

guidance form the basis for these 

recommendations. The specific PAG 

values are derived response levels 

included in these recommendations are based on current agricultural pathway 

and radiation dose models and current 

estimates of risk. The FRC guidance 

provided that protective actions may be 

justified at lower (or higher) projected 

radiation doses depending on the total 

impact of the protective action. Thus, 

FDA's recommendation that protective 

actions be implemented at projected 

radiation doses lower than those 

recommended by FRC doses is 

consistent with the FRC guidance. The 

FRC guidance is applicable to Federal , agencies in their radiation protection 

activities. FDA's recommendations are 

for use by State and local agencies in 

re11ponse planning and implementation 

of protective actions in the event of a 

contamin~ting incident. Further, FDA's 

recommendations would also be used by 

FDA in implementing its authority for 

food in interstate commerce under the 

Federal Food, Drug, and Cosmetic Act. 

FDA's recommendations are being 

forwarded to EPA as the basis for 

revising Federal guidance on food· 

acCidentally contaminated by 

radionuclides. EPA has advised FDA 

that it intends to forward the FDA 

recommendatio.ns to the President under 

its authority 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 • • *''..(This authority was transferred to EPA in 1970 when FRC 

w~s abolished.) 

;The recommendations established in 

this document apply only to human food 

a11d animal feeds accidentally 

contaminated by radionuclides. They 

should not be applied to any other 

source ofradiation exposure. EPA 

already has issued protective action 

guidance for the short..:term accidental 

exposure to airbome releases of 

radioactive materials and intends also 

t~ forward the EPA guides to the 

President as Federal guidance. EPA also 

is. considering the development of 

guidance for acidentally contaminated 

water and for long-term exposures due 

to contaminated land, property, and 

materials. Guidance for each of these 

exposure pathways is mutually 

exclusive. Different guidance for each 

exposure pathway is appropriate 

because different criteria of risk, cost, 

and benefit are involved. Also, each 

exposure pathway may involve different 

sets of protective or restorative actions 

and would relate to different periods of 

time when such actions would be taken. 

2. Several comments expressed 

cbncernabout radiation exposure from 

ll).Ultiple radionuclides and from multiple 

pathways, e.g.; via inhalation. ingestion, 

and external radiation from the cloud 

(plume exposure) and que~tioned why 

particular pathways or radionuclides 

a·nd the does received before 

assessment were not addressed in the 

recommendations. Several comments 

recommended that the PAG's include 

specific guidance for tap water (and 

potable water). Other comments noted 

tpat particular biological forms of 

specific radionuclides (i.e., 

cyanocobalamin Co 60}, would lead to 

significantly different derived response 

levels. 
47076 Federal Register / Vol. 47, No. 205 / Friday, October 22, 1982 I Notices 

FDA adviseo; that the PAG's and the 

J;rotecllve action concepts of FRC apply 

to actions taken to avoid or prevent 

projected radiation dose (or future 

dose}. Thus, by definition, the PAG's for 

food do not con!lider the radiation doses 

alr"'ady incurred from the plume 

pathway or from other sources. The 

population potentially exposed by 

ingestion of contaminated food can be 

divided into that population near the 

s<•urce of contamination and a generally 

much larger population at distances 

where the doses from the cloud are not 

significant. The NRC regulations provide 

Ihat State and local planning regarding 

!Jlume exposure should extend for 10 

miles and the ingestion pathway should 

extend for 50 miles (see 45 J:o"R 55402; 

August 19. 1980). The total population 

tt!Cposed by ingestion, however, is a 

function of the animal feed and human 

food production of any given area and is 

not limited by distance from the source of cdnlamination. Exposure from 

multiple pathways would not be a concern for the more distant population 

group. Further, individuals in this larger 

population would most likely receive 

doses smaller than that projected for 

continuous intake because the 

contaminated food present in the retail 

distribution system would be replaced 

by uncontaminated food. 

.FRC Report No. 5 states that, for 

repetitive occurrences, the total 

projected radiation dose and the total 

impact of protective actions should be 

considered. Similar considerations on a case-by-case basis would then appear to 

be appropriate in the case of multiple 

exposures from the plume and the 

Ingestion pathway. Accordingly, the 

final recommendations are modified to 

note that, specifically in the case of the 

population near the site that consumes locally grown produce, limitations of the 

total dose ahould be considered (see 

paragraph (a)(Z)). The agency concludes, 

however, that a single unified PAG 

covering multiple pathways, e.g., 

external radiation, inhalation, and· 

i11gestion is not practical because 

different actions and impacts are 

involved. Further. FDA's responsibility 

in radiological incident emergency 

re!!ponse planning extends only to 

human food and animal feeds. 

The agency's primary charge is to set 

recommended PAG dose commitment 

limits for the food pathway. Thus, 

deriving response levels for only the 

radfonuclides most likely to enter the 

food chain and deliver the highest dose 

to the population permits FDA to 

establish recommendations that are practical for use in an emergency. In 

rllscusslng with EPA the Jist of definitive 

model:.. FDA and IZPA st.tffs agnwd thiil 

further pathway studies would be 

useful. Elsewlmre in this notice. FDA 

rl!ft:rences models for other 

radionur.lides. providing a resource ftJr 

!hose requiring more details. 

The chemical form of rarlionuc:lidm; in 

the environment may he important wh!m 

considering the deriavation of an appropriata "response level" in spedfic 

situations, but would not change the 

PAG's, which are in terms of projected 

dosEl commitments. Cyanoc:obalamin Co 

60 has not been identified a~< a likely 

constituent of hnalth importance to be 

released from a nuclear reactor accident 

and. therefore, the agency rejects the 

recommendation that it provide derived 

response levels for this ratlionuclide. 

However, after reviewing current 

agricultural and dose models, the 

agency concludes that cesium-134 would 

likely be released and has added it to 

the tables in paragraph (d) of the 

recommend a tiona identifying 

radionuclide concentrations equivaltmt 

to the PAG response levels. 

FDA rejects the comment 

recommending that the PAG·s include 

guidance for water. A memorandum of 

understanding between EPA and FDA 

provides that FDA will have primary 

responsibility over direct and indirect 

additives and other substances In 

drinking water (see 44 FR 42775: July 20. 

1979). Thus, FDA defers to EPA for 

developing guides specifically for 

drinking water. 

3. Three comments requested 

clarification of the proposed 

recomu1endations. including the time over which the guides apply. the time of 

ingestion required to reach the PAG, and 

the time that protective actions should 

he implemented. 

FDA advises that the 

recommendations are intended to 

provide guidance for actions to be 

implemented in an emergency, antl the 

duration of protective action should not 

exceed 1 or 2 months. The agency 

believes that the actions identified in 

paragraphs (a) and (h) of the 

recommendations should be continued 

for a sufficient time to avoid most of the 

emergency radiation dose and to assure that the remaining dose is less than the 

Preventive PAG. This period of time 1:an 

be estimated by considering the 

effective half-life of lhe radioactive 

material taking into account both 

radioactive decay and weathering. Each 

case must be examined separately 

considering the actual levels of 

contamination and the effective half-life 

of the radioactive material present. For 

the pasture/cow/milk pathway, the 

effective half-lives are 5 days for iodine1.11 untl14 days for cc&ium ur strontium. 

A<>~urr.ing that initial contuminatiun Ly 

th~>!>e radionuclides was at the 

Preventive PAG level, radioi:lctive decay 

and weuthering would reduce the le\·cls so thut protective uctions could be 

r:Hased after 1 or z months. 

The model ust:d to compute the 

tliJrived response levels specified in 

paragraph (d) of the recommendations ussumes a continous or infinite ingestion 

period, i.e., intake that is limited only by 

radioactive decay and weathering. This 

is the upprouch recommended in 

estimating the projected radiation dose 

(in the absence of protective actions.). 

Further revisions have been made in the 

·recommendations to clarify these 

aspects. 

4. A comment stated that action 

should be initiated by notification 

received from the facility itself. Another 

cr>mment noted the importance of timely 

announcements to the public of the 

necessity for protective actions. 

These recommendations on protective 

action guides for food and feed are not 

intended to cover other aspects of 

emergency planning for radiological 

incidents. The general responsibilities of 

NRC licensP.es in radiation emergP.ncies 

have been further defined in a rule 

issued by NRC (45 FR 55402; August 19, 

1960). FDA recognizes, however, that 

notification and public announcements are vital to effective protective actions 

and, in paragraph (e}(5) of the 

recommendations. urges that State and 

local emergency pla11s should provide 

for such notice. 

5. A comment offered clarification of 

proposed § 1000.400(g) regarding 

verification of sample measurements, 

while another comment suggested that 

Preventive PAG's should be based on projected levels and that Emergency 

PAG.s require verification. 

The FRC concepts and philosophy. 

which FDA fully endorses, use estimates 

of projected radiation dose as the 

criteria for taking protective action. FDA 

believes that projected radiation dose 

estimates should be based on verified 

measurements of radioactivity in the 

food pathway. Such verification might 

include the analysis of replicate 

samples. laboratory measurements. 

sample analysis by other agencies. 

samples of various envtronmental 

media, and descriptive data of the 

radioactive release and has so provided 

in paragraph (g) of the 

recommends tiona. 

fl. A comment suggested that some 

States do not have the resources to 

evaluate projected radiation doses. The 

comment asked what regulatory agency 

would have control over interstate 
Federai Register I VoL 47. No. 205 / Friday. October 22. .1982 I Notices 4'1017 

shipment of contaminated foodS from 

Slates without sufficient resources and 

what would be the applicable PAG. 

F£t...fA. a.s the lead agency for the 

Federaleffort. is providing to States 

suidance and assistance on emergency . 

response planning including evaluation 

of projected doses. Also. NRC requires 

nuclear power plant licensees to have 

the capability to assess the off-site 

consequences of radioactivity releases 

and to provide notification to Slate and 

local agencies (45 FR 55402; August 19. 

1980). FDA has authority under the 

Federal Food. Drug. and Cosmetic Act to r~move radioactively contaminated road 

from the channels of interstate 

c::ommercc. In this circumstance, FDA 

would use thllse PAG recommendations 

as llu~ basis for implementing 

regulatory action .. 

Risk Estimates 

7. Many comments questioned the risk 

estimates on which FDA based the 

proposed PAG·s. The comments 

especially suggested that risk estimates 

from WASH-1400 (Rei. 4) were of 

questionable validity. Other comments 

argued that the proposed 

recommendations used an analysis o! 

only lethal effect~; that they used an 

absolute risk model: and that genetic 

effects were not adequately considered. 

The risk estimates themselves were 

alleged to be eiTOneous becaW~e recent 

studies show that doubling doses are 

lowar than are those suggested by 

WASH=1400. The tinea capitis study by 

Ron and Madan. which indicates an 

ir.creased probability of thyroid cancm­ :lt an estimated radiation dose o£9 rem 

to the thyroid (Ref. S), was cited as 

evidence that the PAG limits for the 

thyroid were too high. The comments 

requQsted further identification and 

ll!Jpport for using the critical population 

selected. 

Most of these issues were adrlressPd 

in Cha preamble to the FDA proposaL 

The final recommendations issued in 

this notice employ the most recent risk 

estfmates (somatic and genetic) of the 

National Academy of Sciences Commitr~:e on Biological Effects of 

Ionizing Radiatf.rm (Ref. 3). 

The thyroid PAG limits are based on the relative radiation protection guide 

for thyroid compared to whole body 

contained in NRC's current resulations 

(10 CFR Part 20). The derived response 

levels for th-yroid are based on risk 

' ractors (or external x-ray irradiation. 

Therefore. the criticism of the PAG 

limit$ for the thyroid is not applicable. 

no ··credit" ltaving been taken for an 

appare~t lower radiation risk due to 

iodine·131 irradiation of the thyroid 

gland. Further, as discussed above 

under "ORGAN PAC V ALOES ... tbe use 

ofBEIR-lU risk estimates or the ICRP-26 

recommendationa would result in an 

increase of the thyroid PAG relative to 

the whole body PAG. For these reasons. 

1:-"DA believes the PAC limits for 

projected dose commitment to the 

thyroid are conservative when 

considered in light o£ current knowledge 

orradiation to produce equal.bealth 

risks from whole body and specific 

organ doses. 

Although it may be desirable to. 

consider total health effects. not just 

lethal effects. there is a lack of data for 

total health effects to use in such 

comparisons. In the case of the 

variability or natural background. as an 

estimate of acceptable risk. 

consideration of lethal effects or total 

health effects is not involved because 

the comparison is the total dose over a 

lifetime. 

Rational 

8. Several comments questioned the 

rational FDA used in l!etting the specific 

PAG values included in the December 

1978 proposaL A comment from EPA 

stated that the guidance levels should be 

justified on the grounds that it is not 

practical or rensonable to take 

protective actions at lower risk leveis. 

Further. EPA argued that the protective 

action concept for emergency planning 

and response should incorporate the 

principle of keeping radiation exposures as low as reasonably achievable 

(ALARA]. EPA noted that the principle 

nf acceptable risk involves a perception 

of risk that may vary from person to 

person and that the implication that' an acceptable genetic risk has been · 

established qhould' be avoided. 

FDA accepts and endorses the 

ALARA concept. but the extent to which 

a concept, which is used in occupational 

settings. should be applied to emergency 

protective actiona is not clear. To use 

the ALARA concept as the basis for 

spet::ific PA~ values and also require 

ALARA during the implementation of 

emergency protective actions appenrs to 

be redundant and may not be practical 

under emergency conditions. 

FDA advises that these guides do not 

constitute acceptable occupational 

rddiation dose limits nor do they 

constitute acceptable Umits for other 

applications (e.g .. acceptable genetic 

risk). The guides are not intended to be 

used to limit the radiation dose that 

people may receive but instead are to be 

compared to the calculated projected 

dose. i.e .• the future dose that the people 

would receive if no protective action 

were taken in a radiationemergency. In 

this respect, the PAC'a represent trigger 

levels calling for the initiation of 

recommended protective actions. Once 

the protective action is initiated. it 

should be executed so as to prevent as 

much of the calculated projected dose 

from being received as is reasonably 

achievable. This does not mean. 

however, that all doses above guidance 

levels can be prevented. 

Further, the guides are not inteuded to 

prohibit ~aking actions at projected 

exposures lower than the·PAG values. 

They have been derived for general cases and a:re jwst what their nama 

implies, guides. As provided inDC. 

Reports No.5 and No. 1 aad.u 

di11cussed in peragrilph 1 of thia DOtice. 

in the absence ofllignijicant coa.Rraints. 

re,sponsible authaci.iy. may findit 

appropriate to implement low-impact 

protective actiona at projected r.adiation 

dqses less than those specified:iitthe 

gliides. Similarly,.high impactaetioJlll· 

m,ay be justified at higher projected 

doses. The.:se judgments-milS bemade 

ac;:cording to tha facta oieaeh sima.tion. 

Paragraphs (a} (.ZJ and (3] hall1e beea 

added to the finai'recommimdatiGus to 

incorporate this concept.. 

, 9. Several comments que&tianed tlur 

adequacy ofthe level a£'lislt ~ 

a¢ceptable in deriving the proposed 

PAG values. A comment stated that the 

estimated one in a million amma:l 

individual risk ofdeath from JJa:tl:s:ra1 

disasters is extremelJ coW!ei:'Wltiv~ EPA 

suggested that compa:mtiv.e"risk is 

appropriate for perspective but DDt for 

establishing the limits..EPA·furthe: 

.•ested that the population-weighted 

ayerage of the variability. in natural 

background ~ose or the '!'ariaiitm in 

dose due to the natural radioactivity in 

rood should be the basis for judging 

acceptable risk. 

, FDA concludes that the differe:nc~ 

between EPA's sugg~ted approach and 

that employed by FDA largely involve 

the semantics of the, rationale 

descriptiona. As discussed inthe 

preamble to the proposal FD~·nelieves 

that safety (or a safe level ohisk} needs 

to be defmed as·the degree to which.the 

risks at'e judged acceptable. because it 

is not possible to achieve zero risk from 

human endeavors~ Further, ICRP {Ref. 6) ~commends that, for a given 

application invol;-ing radiation. the net 

benefit to society should be po:sifive. 

considering the total costs and impacts 

and the total benefit (this is termed. 

.. Justification"). FDA believes that. to 

establish a PAC. the primary com:em is 

to provide adequate protection (or safe 

level or riskJfor members. of the public. 

~o decide on safety or levels of 

acceptable risk to the pubUc fn:lm a 

cOntaminating event.. FDA introduced 

the estimates of acceptable risk trom 
47078 Federal Register I Vol. 47. No. 205 I Fridr.y, October 22. l!J82 I Notices 

natural disasters and background 

rudiation. These values provided 

background or perspective for FDA's 

judgment that the proposed PAC's 

represent that level of food or reed 

radiation contamination at which 

protective actions should be taken to 

protect the public health: judgment 

which, consistent with FRC Report No. 

5, also involves consideration of the · impacts of the action and the possibility 

of future events. The recommendations are based on the assumption that the 

occurrences of environmental 

contamination requiring protective 

actions in a particular area is an unlikely event, that most individuals 

will never be so exposed, and that any · individual is not likely to be exposed to 

projected doses at the PAG level more 

than once in his or her lifetime. 

FDA continues to believe that the 

average riska from natural disasters and 

variation of background radiation 

provide appropriate bases for judging 

the acceptability of risk represented by 

the Preventive PAG. These 

recommendations incorporate the 

philosophy that action should be·taken 

at the Preventive PAG level of 

contamination to avoid a potential 

public health problem. Should this 

action not be wholly successful. the 

Emergency PAG provides guidance for 

taking action where contaminated food 

is encountered. FDA expects that action 

at the Emergency PAG level of 

contamination would most likely 

involve food produced for consumption: 

by the population near the source of 

contamination. As discussed in 

paragraph 2, this is also the population 

which might receive radiation doses ' 

from multiple pathways. Thus, the 

Emergency PAG might be considered to 

be an upper bound for limiting the total 

radiation dose to individuals. FDA 

emphasizes. however, that the 

Emergency PAG is not a boundary 

between safe levels and hazardous or injury levels of radiation. Individuals 

may receive an occupational dose of 5 

rem each year over the~r working 

lifetime with the expectation of minimal 

Increased risku to the individual. 

Persons in high elevation areas such as Colorado receive about 0.04 rem per 

year (or 2.8 rem in a lifetime) above the 

average background radiation dose for 

the United States population as a whole. 

The Emergency PAC is also consistent 

with the upper range of PAG's proposed 

by EPA for the cloud (plume) pathway 

(Ref. 7J, 

FDA agrees that e. population· 

weighted variable is as applicable to the 

evaluation of comparativ.e risks as is a 

geographic \'ariable. Arguments can be 

made for using either variable. Because 

pr.rsons rather than geographic arem:1 arc the important parameter in the 

evaluation of risk associated with these 

guides, FDA has used populationweighting in estimating the variability of 

the annual external dose from natural 

radiation. A recent EPA study (Ref. ZO) 

indicates that the average population 

dose from external background 

radiation dose is 53 millirem (mrem) per 

year, and the variability in lifetime dose 

taken as two standard deviations is 

about 2,000 mrem. The proposal. which 

indicated that the variation in external 

background was about 600 mrem, 

utilized a geographic weighting of State 

averages. 

Radioactivity in food contributes 

about 20 mrem per year to average 

population doses and about 17 mrem per 

year of-this dose results from potassium· 

40 (Ref. a)."'Measurements of potassium· 

40 (and stable potassium) indicate that 

variability (two standard deviations) of 

the potassium-40 dose is about 28 

percent or a lifetime dose of 350 mrem. It 

should be noted that body levels of 

potassium are regulated by metabolic 

processes and not dietary selection or 

residence. The variation of the internal 

dose is about one-fifth of the variation 

from external background radiation. 

FDA has retained the proposed 

preventive PAG of 500 mrem whole 

body even though the newer data 

indicate a greater variation in external 

background radiation. 

FDA did not consider perceived risks 

in deriving the proposed PAC values 

because perceived risk presents 

numerous problems in its 

appropriateness and application. If the 

factor of perception is added to the 

equation, scientific analysis is 

impossible. . 

10. Two comments questioned the 

assumptions that the Emergency PAG 

might apply to 15 million people and 

that the Preventive PAG might apply to 

the entire United States. One comment 

noted that 15 million persons are more than that population currently within 25 

miles of any United States reactor sites: 

thus, using this figure results in guides 

more.restrictive than necessary. The 

other comment noted that, by reducing 

the population involved, and. 

unacceptably high value could result. 

The ratio of total United States 

population to the maximum number of 

people in the vicinity of an operating 

reactor could be erroneously interpreted 

so that progressively smaller 

populations would be subject to 

progressively larger individual risks. 

This is not the intent of the 

recommendations. Hence, the risk from 

natural disasters. the variation in the . population-weighted natural background 

mdialion dose to the total population. 

and the variation in dose due to 

ingestion of food, have been .used to 

provide the basis for the Preventive 

PAC. The basis for the Emergency PAC 

involves considerations of (1) The ratio 

between average and maximum 

individual radiation doses (taken as 1 to 

10), (2) the cost or low and high impact 

protective actions. (3) the relative risks 

from natural disasters, (4) health impact, 

(5) the upper range of the PAG's 

proposed by EPA (5 rem projected 

radiation dose to the whole body and 25 

rem projected dose to the thyroid). and 

(6] radiation doses from multiple 

pathways. 

tl. A comment, citing experience with 

other contaminants, suggested that 

further consideration should be given to 

the problem of marketability of foods 

containing low levels of radioactivity. 

Marketability is not a concern for 

PAG development. However, the 

publication of the PAG's should enhance 

marketability of foods because it will 

enhance public confidence in food 

sa!Elty. Also, FEMA has been 

specifically directed to undertake a 

public information progr~m related to 

radiation emergencies to allay public · fears and perceptions. 

lZ. A comment noted the difficulty in . assessing the impacts of and the 

benefits to be gained from protective 

actions. Another comment suggested 

that there were lower impatt actions 

which could be implemented to keep 

food off the market until radiation levels 

in the food approach normal 

background. · 

The recommendation that planning 

officials consider the impacts of 

protective actions In implementing 

action does not imply that a mathematical analysis is required. 

Rather, FDA intends that the local 

situation, resources, and impacts that 

are important in assuring effective 

protective actions be considered in 

selecting any actions to be implemented. 

As discussed in paragraph 8, if the local 

constraints permit a low impact action, 

this can be appropriate at lower 

projected doses. Because it is not 

possible in general guidance to consider 

fully all local constraints, the PAG's · 

represent FDA's judgment as to when 

protective actions are appropriate. 

Agricultural and Dose Models 

13. Several comments noted errors 

either in approach or calculations 

regarding the proposed agricultural and 

dose models, while others specifically 

noted that there are newer and better 
Federal Register / Vol. 47, No. 205 / Friday, October 22, 1982 J Notices 4'7079 

models for use in computation of the recommendations and are listed under Assistance Plan (IRAP) coordinates the· 

derived response levels. "Forage Concentration". provision of Federal assistance and an 

FDA appreciates the careful review 

and the suggestions as to better data 

and models. The references suggested. 

as well as other current reports. have 

been carefully reviewed and appropriate 

ones are being used as the basis for 

computation of the derived response 

levels for the final PAG's. The specific 

models and data being used are liB 

follows: 

Agricultural Model-UCRJ...-51939, 1977 


{Ref. 9}. · 


Intake per unit deposition-Table B-1, 


UCRL-51939 (Ref. 9}. 


Peak milk activity-Equation 8. UCRL51939 (Ref. 9}. . 


Area grazed by cow--45 square meters/ 


duy. UCRL-51939 (Ref. 9}. 


Initial retention on forage--4.5 fraction. 


UCRL-51939 {Ref. 9}. 


Forage yie!d--4.25 kilogram/square meter 


(dry wP.ight}, UCRL-51939 (Ref. 9}. 


Milk consumption--4.71it.er/day infant. 

ICRP-23. 1974 (Ref. 10);--4.55liter/day adult. 

USDA, 1965 (Ref.ll). . 

Dose c~mversion factors (rem per 


microcurie ingested). 


---,..---...,..---..,----------· . . lnfWit .Mull ---~ j----,-·--­

lodi<le-131. ....... _ 1& t.6 Wellman -Anger, 1971 f!'laf. 12). 

Cesoum·134......... 0.118 0.068 ~RNtJNOREG/ 

TM-190. 1lJ78 (Ref. 

13). 

Infant~ 

Item IICkllt ba-s on relll1ive body~ 

70 ~i!ograms (!<g) and 7.71cQand~ 

I r<ilonlion. !02 dayS 

and 19.5 ~. adult 

-in!.... 

C..S.Um--137.........., 0.071 0.061 NCRP No. 52, 1917 


f!'lef. 14). 


Slrot1!1Um-<l9 ........ 0.1941 0.012 Adult. ICRP-30. 1919 


CAe1.15). 

S:r<lr-.toum·90 ..••..1 2.49 0.70 Infant. Pepwotl!'l and 

Ve'll'lllt1, 1973 IRe!. 

____ l ____l__ I l&j. . '-· 

The use of the newer agricultural 


model (Ref. 9J has resulted in a 20 


pP.rcent increase ln the iodine-131 


. derived response levels identified in 

paragraph (d)(t) and (dJ(2} of the · 

l'l'commenda'tions. Generallv. similar 

magnitmit! changes are reflected in the 

derived response levels for the other 

radionuclides. Newer data on iodine-131 

dose conversion factors (Ref. 17) would 

have further increased the derived 

response levels for that radionuclide by 

. about 40 percent. but these data have 

. nol been used pending their acceptan~ 

by United States recommending 

authorities. In addition, the proposal 

r:ontained a systematic error inthat the 

pasture derived response levels were 

stated to be based on fresh weight but 

were in fact based on dry weight. Fresh 

weight values(~ of dry weight values) 

i1te identified in the fmal . ' . . 

Other Comments 

14. A comment addressed the 

definition of the critical or sensitive 

population for the tables in proposed 

§ 1090.400(d) an~ observed that there is 

a greater risk per rem to the younger age 

groups than to adults. Another comment 

requested further explanation of the 

relative ability to protect children and 

adults. 

FDA agrees that, ideally, the critical 

segment of the population should be 

defmed in terms of the greatest risk per 

unit intake. However, this would 

introduce greater complexity into the 

recommendations than. is justified, 

because the risk estimates are uncertain. 

The final recommendations provide 

derived response levels for infants· at the 

Preventive PAG and infants and adults 

for the Emergency PAG. · 

FDA has reexamined the available 

data and concludes that taking action at 

the Preventive PAG (based on· the infant 

as the critical or sensitive population] 

will also provide protection of the Cetus 

from the mother's ingestion of milk. The 

definition,of newborn infant In the 

tables in paragraph {d) of the PAG's has 

.been revised to reflect this conclusion. 

15. EPA commented that its 

regulations governing drinking water (40 

CFR Subchapter D) permit blending of 

water to meet maximum contaminant 

levels. EPA suggested that FDA's shortterm recommendations should be 

compatible with the long-term EPA 

regulations. 

As stated in paragraphs 1 and 2 of this 

notice, FDA's recommendations apply to 

human food and animal feed. whereas 

EPA is responsible for providing 

guidance on contaminated water. Also. as discussed in paragraph 3 of the 

proposal. there is a long-standing FDA 

policy that blending of food is unlawful 

under the Federal Food, Drug. and 

Cosmetic Act. -Further, these guides are 

intended for protective actions under 

emergency situations and are not for 

continuous expoRure app!ic:ations. For 

these reasons, FDA concludes that the 

differences between its 

recommendations and EPA's regulations 

are appropriate. · 16. Two comments were received on 

the adequacy or availability of 

resources for sampling and analysis of 

State, local. and Federal agencies·and 

the adequacy of guidance on sampling 

procedures. 

These recommendations are not 

designed to provic;le a compendium of 

sampling techniques, methods, or . 

resources. The Department of Energy 

through its Interagency Radiological 

Offsite Instrumentation Task Force of 

the Federal Radiological Preparedness 

Coordinating Committee administered 

by FEMA is developins specific 

guidance on instrumentation and 

mt;!thods for sampling food {R~f, 21)~ 

Cqst Analysis. 

17. Several comments argued that 

FDA's cost/benefit analysis- used to 

establish the PAG levels was 

inadequate. Commeut& stated that it is 

not appropriate to assigR a unique fuied 

dollar value to the adverse health 

effects associated with one perscm-rem 

of dOse. 

FDA advisetJ that its cost/benet;it 

analysis was not conducted ta establish 

the PAG levels. FDA considers liUcft. use 

inappropriate in part because of.the 

inability to assess definitiv~y the tot-at 

societal impacts (positive and negative) 

of such actions. Rather, the cost/benefit 

a~alysis was used to detel'IIline wD.ether 

protective actions at the recommen.dad· 

PAG's would provide a net 110eietal 

benefit. To make such an. assessment. it 

is necessary to place a dollar value on a 

p~rson-rem of dose. 

:ta. Several comments. also questionedthe appropriateness ofthe assumption in 

the cost/benefit analysis of 23 days·of 

protective action. the need to addressradionuclides other than iodine-1:3:1:, and 

the need to consider the impact orother 

protective actions. 

iThe cost assessments have been 

extensively revised to consider alf the 

radionuclides for which derived 

response levels are provided in tlie 

recommendations and to incorporate 

updated cost data and risk estimates 

(Ref. 22). The cost/benefit analysis is 

limited to the condemnation of milk and 

the use of stored feed because accident 

analyses indicate that th~milk pathway 

is. the most likely to require protective 

action. Further, these two actions are 

the most likely protective actions that 

\Vill be implemented. 

; FDA approached the cost/benefit 

analysis by calculating the . 

concentration of radioactivity in milk at 

which the cost of taking action equals 

the risk avoided by the action taken on 

aldaily milk intake basis. The 

assessment was done on a population 

b~sis and considered only the direct · · 

costs of the protective actions. The 

analysis indicates that, for restricting 

feed to stored feed. the coat-equalsb~mefit concentrations are about onefi,ftieth to one-eightieth of the. Preventive 

PAG level (derived peak milk 

d:mcentJ ation) for iodine-131, cesium134, and cesiu!l1·137 and about one-third. 
47080 Fede1al Register I Vol. 47, No. 205 I Friday, October 22, 1982 I Notices 

of the level for strontium-89 and 

strontium-90. For condemnation of milk, 

based on value at the farm, the costequals-benefit concentrations are 

similar fractions of the Emergency PAG 

levels (derived peak milk 

concentration). If condemnation of milk 

is based on retail market value, the costequals-benefit concentrations are 

greater by a factor of two. Thus. it 

appears that protective actions at the 

Preventive or Emergency PAG levels 

will yield a net societal benefit. 

Howe'l£er, In the case of strontium-89 

and strontium-90, protective action will 

yield a benefit only for concentrations 

greater than about one-third the derived 

peak values. In the case of iodine-131, 

cesium-134, and cesium-137, protective 

actions could be continued to avoid 95 

percent or the projected radiation dose 

for initial peak concentrations at the 

PAG level. 

Roforentef 

The following Information has been placed on display In the Dockets Management 

Branch (HFA-305), Food and Drug 

Administration, Rm. 4-62, 5600 Fishers l..ane. 

Rockville, MD 20857, and may be seen between 9 a.m. and 4 p.m., Monday through 

Friday. 

1. Federal Radiation Council. Memorandum 

for the President. "Radiation Protection 

Guidance for Federal Agencies." Federal 

Rozjatot, August 22, 1964 (29 FR 12056). and 

Report No.5 (July 1964). 

2. Federel Radiation Council. Memorandum. 

for the President, "Radiation Protection 

Guidance for Federal Agencies:· Fodoral 

Resistor," May 22. 1965 (30 FR 6953). and 

Report No.7 (May 1965). • 3. National Academy of Sciences/National 

Research Council, ''The Effects on Population 

of Exposure to Low Levels of Ionizing 

Radiation."' Report of the Advisory 

Committee on Biolosical Effects of Ionizing 

Radiation (BEJR-111) (1980). 

4. United States Nucl.ear Regulatory 

Commlulon, Reactor Safety Study. WASH1400, Appendix VI (October 1975). 

5. Ron, E. and B. Madan, "Benign and 

Malignant Thyroid Neoplasms After 

Childhood Irradiation for Tinea Capitis."' 

journal ofthe Notional Cancer lnslilule. Vol. 

60, No.1 (July 1980)• 

6. International Commission on Radiological Protection (ICRP), 

Recommendations of the International 

Commlosion on Radiological Protection, ICRP 

Publication 26, Annals of the ICRP. Pergamon 

Press (1977). 

7. Environmental Protection Agency, 

"Manual of Protective Action Guides and 

Protective Actions for Nuclear Incidents."' 

EPA 520/1-75-001, revised June 1980. 

8. United Nations Scientific Committee on the Effects ofAtomic Radiation, 1977 Report, 

United Nations, New York (1977). 

9. Ns. Y. C., C. S. Colsher, D. J. Quinn. and 

S. E. Thompaon, "Transfer Coefficients for 

the Prediction of the Dose to Man Via the 

Forage·Cow-Mil1c Pathway from 

Radlonuclidea Released to the Biosphere," 

UCRL-51939, Lawrence Livermore 

Laboratory (July 15, 1977). 

10. International Commission on Radiological Protection. Report of a Task 

Group of Committee 2 on Reference Man, 

Publication 23. p. 360. Pergamon Press. 

Oxford (1974). 

11. U.f Department of Agriculture, 

"Household f, 1d Consumption Survey 1965­

1966." 

12. Wellman. H. N. and R. T. Anger, 


"Radioiodine Dosimetry and the Use of 


Radioiodine& Other Than 1311in Thyroid 


Diagnosis," S11minars in Nuclear Mediciue. 


3:356 (1971). 

13. Killough. G. G., D. E. Dunning. S. R. 

Bernard. and J. C. Pleasant, "Estimates of 

Internal Dose Equivalent to 22 Target Organs 

for Radionuclides Occurring in Routine 

Releases from Nuclear Fuel-Cycle Facilities, 

Vol. 1."' ORNL/NUREG/TM-190. Oak Ridge 

National Laboratory (June 1976). 

14. National Council on Radiation 

Protection and Measurements, "Cesium-137 

From the Environment to Man: Metabolism 

and Dose." NCRP Report No. 52, Washington 

(January 15, 1977). 

15. International Commission on 

Radiological Protection, Limits for Intakes of 

Radionuclides by Workers. ICRP Publication 

30, Part 1. Annals of the ICRP. Pergamon 

Press (1979). 

16. Papworth, D. C., and J. Vennart, 

"Retention of "Sr in Human Bone at Different 

Ages and Resulting Radiation Doses," 

Physics in Medicine and Biology. 18:169-166 

(1973). 

17. Kereiakea, J. G.. P. A. Feller. F. A. 

Ascoli, S. R. Thomas. M. J. Gelfand. and E. L. 

Saenger, "Pediatric Radiopharmaceutical 

Dosimetry" in "Radiopharmaceutical 

Dosimetry Symposium," April 26-29, 1976, 

HEW Publication (FDA) 76-8044 (June 1976). 

18. National Academy of Sciences/ 

National Research Council, "The Effects on Populations of Exposure !o Low Levels of 

Ionizing Radiation," Report of the Advisory 

Committee on Biological Effects of Ionizing 

Radiation (BEIR-I) (1972). 

19. National Council on Radiation 

Protection and Measurements (NCRP). "Basic 

Radiation Protection Criteria," NCRP Report 

No. 39, Washington (1971). 

20. Bogen, K. T.. and A. S. Goldin. 

"Population Exposure to External Natural 

Radiation Background in the United States."' 

ORP/SEPD-ro-12. Environmental Protection 

Agency, Washington, DC (April1961). 

21. Federal interagency Task Force on 

Offsite Emergency Instrumentation for 

Nuclear Accidents, "Cui dance on Off site 

Emergency Radiation Measurement Systems: 

Phase 2, Monitoring and Measurement of 

Radionuclides to Determine Dose 

Commitment in the Milk Pathway," 

developed by Exxon Nuclear Idaho Co. Inc.. Idaho Falls, ID. Draft, July 1961 [to be 

published by FEMA). 

22. Shleien, B., G. D. Schmidt. and R. P. 

Chiacchierinl, "Background for Protective 

Action Recommendations; Accidental 

Radioactive Contamination of Food and 

Animal Feeds," September 1981, Department 

of Health and Human Services. Food arid 

Drug Administration. Bureau of Radiological 

Health, Rockville, MD. 

Pertinent background data and 

information on the recommendations are 

on file in the Dockets Management 

Branch. and copies are available from 

that office (address above). 

Based upon review of the comments 

received on the proposal of December 

15. 1978 (43 FR 58790), and FDA's further 

consideration of the need to provide 

guidance to State and local agencies for 

use in emergency response planning in 

the event that an incident results in the 

rudioactive contamination of human 

food or animal feed. the agency offers 

the following recommendations 

regarding protective action planning for 

human food and animal feeds: 

Accidental Radioactive Contamination 

of Human Food and Animal Feeds; 

Recommendations for State and Local 

Agencies 

(a] Applicability. (1) These 

recommendations are for use by 

appropriate State or local agencies in 

response planning and the conduct of 

radiation protection activities involving 

the production, processing, distribution, 

and use of human food and animal feeds 

in the event of an incident resulting in 

the lease of radioactivity to the 

environment. The Food and Drug 

Administration (FDA) recommends that 

this guidance be used on a case-by-case 

basis to determine the need for taking 

appropriate protective action in the 

event of a diversity of contaminating 

events, such as nuclear facility 

accidents, transportation accidents. and 

fallout from nuclear devices. 

(Z) Protective actions are appropriate 

when the health benefits associated 

with the reduction in exposure to be 

achieved are sufficient to offset the 

undesirable features of the protective 

actions. The Protective Action Guides 

(PAG'sj in paragraph (c) of these 

recommendations represent FDA's 

judgment as to the level of food 

contamination resulting from radiation 

incidents at which protective action 

should be taken to protect the public 

health. Further, as provided by Federal 

guidance issued by the Federal 

Radiation Council, if, in a particular 

situation, and effective action with low 

total impact is available, initiation of 

such action at a projected dose lower 

than the PAG may be justifiable. If only 

very high-impact action would be 

effective, initiation of such action at a 

projected dose higher than the PAG may 

be justifiable. (See 29 FR 12056; August 

22. 1964.) A basic assumption in the 

development of protecti.ve action 

guidance is that a condition requiring 

protective action is unusual and should 

not be expected to occur frequently. 
Federal Register I Vol. 47, No. 205 I Friday, October 22, 1982 I Notices 47081 

Circumstances that involve repetitive 

occurrence, a substantial probability of 

recurrence within a period of 1 or 2 

years, or exposure from multiple sources 

{such as airborne cloud and food 

pathway) would require special 

consideration. In such a case, the total 

projected dose from the several events 

and the total impact of the protective 

actions that might be taken to avoid the 

future dose from one or more of these 

events may need to be considered. In 

any event, the numerical values selected 

for the PAG's are not intended to 

authorize deliberate releases expected 

to result in absorbed doses of these 

magnitudes. 

(3} A protective action is an action or 

measure taken to avoid most of the 

radiation dose that would occur from 

future ingestion of foods contaminated 

with radioactive materials. These 

recommendations are intended for 

implementation within hours or days 

from the time an emergency is 

recognized. The action recommended to 

be taken should be continued for a 

sufficient time to avoid most of the 

projected dose. Evaluation of when to 

cease a protective action should be 

made on a case-by-case basis 

considering the specific incident and the 

food f!Upply contaminated. In the case of 

the pasture/cow/milk/person pathway, 

for which derived "response levels" are 

provided in paragraph (d) of these 

recommendations, it is expected that 

actions would not need to extend 

beyond 1 or 2 months due to the 

reduction of forage concentrations by 

weathering {14-day half-life assumed). 

In the case of fresh produce directly 

contaminated by deposition from the 

cloud, actions would be necessary at the 

time of harvest. This guidance is not 

intended to apply to the problems of 

long-term food pathway contamination 

where adequate time after the incident 

is available to evaluate the public health 

consequences of food contamination 

.using current-recommendations and the 

guidance in Federal Radiation Council 

(FRC) Report No. 5, July 1964 and Report 

No. 7, May 1965. 

(b) Definitions. (1) "Dose" is a general 

term denoting the quantity. of radiation 

or energy absorbed. For special 

purposes it must be appropriately 

qualified. In these recommendations it 

refers specifically to the term "dose 

equivalent." 

(2) "Dose commitment" means the 

radiation dose equivalent received by 

an exposed individual to the organ cited 

over a lifetime from a !Jingle event. 

(3) "Dose equivalent" is a quantity 

that expresses all radiation on a 

common scale for calculating the 

effective absorbed dose. It is defined as 

the product of the absorbed dose in r~ds 

and certain modifying factors. The umt 

of dose equivalent is the rem. 

(4) "Projected dose commitment" 

means the dose commitment that would 

be received in the future by individuals 

in the population group .from the 

contaminating event if no proteptive 

action were taken. 

(5) "Protective action" means an 


action taken to avoid most of the 


exposure to radiation that would occur 


from future ingestion of foods 


contaminated with radioactive 


materials. 


(6) "Protective action guide {PAG)" 

means the projected dose commitment 

values to individuals in the general 

population that warrant protective 

action following a release of radioactive 

material. Protective action would be 

warranted if the expected individual 

dose reduction is not offset by negative 

social, economic, or health effects. The 

PAG does not include the dose that has 

unavoidably occurred before the 

assessment. 

(7) "Preventive PAG" is the projected 

dose commitment value at which 

responsible officials should take 

protective actions having minimal ipact 

to prevent or reduce the radioactive 

contamination of human food or animal 

feeds. 

(8) "Emergency PAG" is the projected 

dose commitment value at which 

responsible officials should isolate food 

containing radioactivity to prevent its 

introduction into commerce and at 

Response leYe!s for ptevenlive PAG 

which the responsible officials should 

determine whether condemnation or 

another disposition is appropriate. At 

the Emergency PAG, higher impact 

actions are justified because of the 

projected health hazards. 

(9) "Rad" means the unit of absorbed 

dose equal to 0.01 Joule per kilogram in 

any medium. 

(10} "Rem" is a special unit of dose 

equivalent..The dose equivalent in rems 

is numerically equal to the absorbed 

dose in rads multiplied by the quality 

factor, the distribution factor, and any 

other necessary modifying factors. 

(11) "Response level" means the 


activity of a specific radionuclide (i) · 
 initially deposited on pasture: or (ii) per 


unit weight or volume of food or animal 


feed; or (iii) in the total dietary intake 


which corresponds to a particular PAG. 


(c) Protective action guides {PAC's]. 

To permit flexibility of acti!)n for the 

reduction of radiation expdsure to the 

public via the food pathway due to the 

occurrence of acontaminating event, the 

fo.lloWing Preventive and Emergency 

PAG's for an exposed inqividual in the 

population ar.e adopte.d: . (1) Preventive PAC which is (i) 1.5 


rem projected dose commitment to the 
 . thyroid, or {ii) 0.5 rem projected dose 


commitment to the whole body, bone 


niarrow, or any other organ. 
 :(2) Emergency PAC which is (i) 15 rem 

projected dose commitment to the 

thyroid, or (ii) 5 rem projected dose 

commitment to the whole body, bone 

marrow, or any other organ. 

(d) Response levels eq~ivalent to 

PAC. Although the basic PAG 

recommendations are given in terms of 

projected dose equivalent, it is often 

more convenient to utilize specific 

radionuclide concentrations upon which 

to initiate protective action. Derived 

response levels equivalent to the PAG's 

for radionuclides of interest are: · (1) Response level for Preventive 


PAC. Infant 1 as critical segment of 


population. 


, 1 Newborn infant Includes fetus (pregnant 

Women) aa critical segment of population fo• iodinetill. For other radionuclides, "Infant" refers to child 

less than 1 year of age. 

131,• 134ca• 137.,• 80., .... 0.13 2 3 0.5 a Initial ActiYily AIM Deposition (miaocurieslsquare meter)··-············-···················-··········································---·············--···--·-············-······--····· ForiiiJ8 Concentration • (rnk:rocurios/kik>gtam) ....................................................................................................... -··········-····················--.. •••··•••••••··••·•···· 	 0.05 0.8 1.3 0.18 3 

O.o15 0.15 0.24 0.008 0.14 Peak Milk ActiYily (microc:uries/li11W) ···········-···························································································································-··················-······-··················· 0.09 4 7 o.z 2.8 To.., inlalce (mtctOCUries) ··············-······-··············································································-··········-············-··············-···········-··-·-·-·····-··· ...... 

'From fallout. ~131 Ia 1he onty radioiodine of significance wi1h respecllo m~k conlamination beyond 1he first day. In case of a reactor accident, the cumulative intake of iodino-133,. 

mtlk Is aboul 2 percent 01 iodlne-131 assumong equovalent depositton. 1Fnnh weight. 'lnlllke of'*"""' • the meatlper.;on pathway for adults mAy exceed that of the m~k pathway; therefore. such levels in milk should cauaa surv&illance end protective actions for meat u 

81'Pfoprl&te. If both C8Sium-134 and c8SIUm-137 are equally ptesent as might be expected for reactor accidents, 1he msponse IIM!Is should be reduced bi' a f&clor of two. 
---- ---

47082 Federal Register I Vol. 47, No. 205 I Friday, October 22, 1982 I Notices 

(2) Response lel'e/ foJ· Emergency PAG. The response levels equivahmt to the Emergency PAG. are presented for both 

Infanta and adults to permit use of either level and thus assure a flexible approach to taking action in cases where exposure 

of the most critical portion of the population (infants and pregnant women) can be prevented:

--·-·-.. · f 1;,,. I 134c,' +. 137.-' I uo.. 

Response lootels lor emergency PAG ~,J..____.:::r-· ·-· ---- -r --­ -------------------· ~:1-~~i .!_~•~: l ~~.t .. I_!_~~~~. Adutl tntant• Adun Infant' Adull

lnllill AetMty ArM OepositiOI1 (n.:rocunn/aquare metef)............................................................. 1.3 I 18 20 L40 I 30 50 I 5 20 80 11100


For.geCooatiilal!on'(~/kilogram) .....................................................................~...........0.5 7 8 t7i 13 19 1.8 8 30 700 

1 Peak WkAciM!y (lniCtOCUMalliiiK) ...............___........................................................................... 0.15 2 1.5 3 24 4 0.09 0.4 1.4 30 


Total inlllke (mlcroeu.ej ·-................................................................................................. 0.9 10 40 70 70 I 80 2 7 26 400 
 _.....__ __._____ -- ..__L___L---1---L.. 

appt~l& H bolh Clltl<llll-134 and C8SIUm-137 .,. equally present, u might be expecled lor ntactor &CC1dants. 

'Nnbom inCanltneludn 1etua (pregnant women) u crilicalaegment Of populahon tor IOdine-131. 

'"'nnann" rallnl 10 child leu thall 1 yur Of •· . . 'From fallout. ~131 • the only racllotodine Of ~~gnificance with respec110 milk contamination beyond the first dey. In case ot a reactor accident the cumulative intake of Kldlne·133 VII milk • 8bouC 2 '*"""Of IOdone-131 &L'IUtlllllg equ~~~alent ~.

::= w the meet/J)el*>ll pathway lor lldulb may exceed thai ol the mill< pa1hway; lherlllore, such levels in milk should ca""' SUMttllance and protec:tivo actions lor meat as 

(e) Implementation. When using the 

PAG'a and associated response levels 

for response planning or protective 

actio1:1s, the following conditions should 

be followed: 

(l}Specificfood items. To obtain the 

response level (microcurie/kilogram) 

equivalent to the PAG for other specific 

foods, it ia necessary to weigh the 

contribution of the individual food to the 

·total dietary intake; thus, 

Reaponae Level .,. Total inta~e (mi~ocuries) Consumption (k1lograms) 

Whem: Total intake (microcuries) Cor the 

appropriate PAG and radionuclide is 

given in plll'agraph (d) of these 

recommendstiona 

and 

Consumption il the product of the average 

dally consumption specified in paragraph 

(t>)(l)(l) of these recommendations and 

the dsya of Intake of the contaminated 

food 011pecified in paragraph (e)(1)[ii) of 

these recommendations. 

(i) The daily consumption of specific 

foods in kilogramtJ per day for the 

general population is given in the 

following table: 

Food 

...., CtMf1\ loe cnem •-----1 

,..--------·-·--·-·-· Fleur,~-------·­

llllk"Y pn:>Q.da-----·­

l'goAy ~--------------­ ·---·-·--... 

Filii Wid lhelllllh...-·---------·­ EQjlll ....-­ Sugw.lin.opa, honey,~ *----·-1 -'potaii)M----·--..-·.. VIQIIIblle. tr.h (acluding polaloM).___ 

c.nnecl. "-t, Clriecl -­

v~;..a (lingle ~~'-----1 

Ftull. ~tr.h-----~---------­ CIWW'Ied. frozen. Clrieci---------

Ftull. (lingle llrength)-----·--·­

.570 

.055 

.0111 

.150 

.220 

.055 

.023 

.055 

.073 

.105 

.145 

.on 

.0011 

.185 

.D38 

.045 

--------.,~ for the 

Food ,= -------------------~~~, Other beYerages (soft drinka, coli 80 

Soup and graYIM (mottty conclensed 036 

Nuts and=::.::::::~~:::::::::::::::::~::::::::::::::::::::::t~ •Expressed .. Clllaum equNU!nt; that ia, the quantity of whole fluid miHt 10 which dairy producla .,. equrvaklnt in CIICIIII'I! content 

(il) Assessment of the effective days 

of intake should consider the specific 

food, the population involved, the food 

distribution system, and the 

radionuclide. Whether the food is 

distributed to the retail market or 

produced for home use will significantly 

affect the intake in most instances. 

Thus, while assessment of intake should 

be on a case-by-case basis, some 

general comments may be useful in 

specific circumstances. 

(a) For short half-life rlidionuclides, 

radioactive decay will limit the 

ingestion of radioactive materials and 

the effective "days of intake". The 

effective "days of intake" in this case is 

1.44 times the radiological half-life. For 

iodine-131 (half-life-8.05 days), the 

effective "days of intake" is, thus, 11 

days. 

(b) Where the food product is being 

harvested on a daily basis, it may be 

reasonable to assume reduction of 

contamination due to weathering. As an 

initial assessment. It may be appropriate 

to assume a 14-day weathering half-life 

(used for forage in pasture/cow/milk 

pathway) pending further evaluation. In 

this case, the effective "days of intake" 

ia 20 days. A combination of radioactive 

decay and weathering would result in 

an effective half-life for iodine-131 of 5 

days and reduce the "days of intake'' to 

7 days. 

(c) In the case of a food which is sold 

in the retail market, the effective "days 

the responl8 • levela should be ntduc8d by a factor of 2. 

of intake" would probably be limited by 

the quantity purchased at a given time. 

For most food, especially fresh produce, 

this would probably be about a 1 week 

supply. In some cases, however. larger 

quantities would be purchased for home 

canning or freezing. For moRt foods and 

members of the public, an effective 

"days of intake" 30 days is probably 

conservative. 

(iii) For population groups having 

significantly different dietary intakes, an 

appropriate adjustment of dietary 

factors should be made. 

(2) Radianuc/ide mixtures. If a 

mixture of radionuclides is present, the 

sum of all the ratios of the concentration 

of each specific radionulide to its 

specific response level equivalent to the 

PAG should be less than one. 

(3} Other radionuclides. The response 

level for the Preventive and Emergency 

PAG for other radionuclides should be 

calculated from dose commitment 

factors available in the literature 

(Killough, G. G., et al., ORNL/NUREG/ 

.TM-190 (1978) (adult only), and U.S. 


Nuclear Regulatory Commission Reg. 


Guide 1.109 (1977)). 


(4} Other critical organs. Dose 

commitment factors in U.S. Nuclear 

Regulatory Commission Reg. Guide 1.189 

(1977). refer to bone rather than bone 

marrow dose commitments. For the 

purpose of these recommendations, dose 

commitment to the bone marrow is 

considered to be 0.3 of the bone dose 

commitment. This is based on the ratio 

of dose rate per unit activity in the bone 

marrow to dose rate per unit activity in 

a small tissue-filled cavity in bone and 

assumes that strontium-90 ia distributed 

only in the mineral bone (Spiers, F. W., 

et al., in "Biomedical Implications of 

Radiostrontium Exposure," AEC 

Symposium 25 (1972). The ratio for 

strontium-89 is the same because the 

mean particle energies are similar (0.56 

MeV (megaelectronvolts)). Situations 

could arise in which an organ other than 

those discussed in this paragraph could 
Federal Register I Vol. 47. No. 205 I Friday. October ZZ.: 198Z I Notices 

be considered to be the organ receiving 

the highest dose per unit intake. In the 

case of exposure via the food chain, 

depending on the radionuclide under 

consideration. the gastrointestinal tract 

could be the primary organ exposed. 

The references cited in paragraph (e)(3} 

of these recommendations contain dose 

commitment factors for the following 

organa: bone, kidneys, liver, ovaries, . spleen, whole body, and gastrointestinal 

tracl 

(5} Prompt notification of State and 

local agencies regarding the occurrence 

of an incident having potential public 

health consequences is of significant 

value in the implementation of effective 

protective actions. Such notification is 

particularly important for protective 

actions to prevent exposures from the 

airborne cloud but is also of value for 

food pathway contamination. 

Accordingly, this protective action 

guidance should be incorPorated in 

State/local emergency plans which 

provide for coordination with nuclear 

facility operators including prompt 

notification of accidents and technical 

communication regarding public health 

consequences and protective action. 

(f) Sampling parameter. General!y, 

sites for sample collection should be the 

retail market, the processing plant, and 

the farm. Sample collection at the milk 

procellsing plant may be more effcient in 

determining the extent of the food 

pathway contamination. The geographic 

area where protective actions are 

implemented should be based on 

considerations of the wind direction and 

atmospheric transport, measurements by 

airborne and ground survey teams of the 

radioactive cloud and surface 

deposition, and measurements in the 

food pathway. · 

(g) Recommended methods of 

analysis. Techniques for measurement 

of radionuclide concentrationa should 

have detection limits equal to or less 

than the response levels equivalent to 

specific PAG. Some useful methods of 

radionuclide analysis can be found in: 

· (1) Laboratory Mcthods-"HASL 

Procedure Manual." edited by John H. 

Harley, HASL 300 ERDA. Health and 

Safety Laboratory, New York. NY, 1973: 

"Rapid Methods for Estimating Fission 

Product Concentrations in Milk," U.S. 

Department of Health, Education, and 

Welfare, Public Health Service 

Publication No. 999-R'-2, May 1963; 

"Evaluation of Ion Exchange Cartridges 

for Field Sampling of Iodine-131 in 

Milk," Johnson, R. H. and T. C. Reavy, 

Nature, 208. {5012): 750-752, November 

20,1965:and 

(2) Field Methods-Kearny, C. H., 

ORNL 4900, November 1973; Distenfeld, 

c. and J. Klemish, Brookhaven National 

Laboratory, NUREG/CR~315, 

December 1978: and International 

Atomic Eeergy Agency, "Environme~tal 

Monitoring in Emergency Situationlf," 

1966. Analysis need not be limited to 

these methodologies but should provide 

comparable results. Action should not 

be taken without verification of the 

analysis. Such verification might include 

the analysis of duplicate samples, 

laboratory measurements, sample 

analysis by other agencies, sample 

analysis of various environmental 

media, and descriptive data on 

radioactive release. 

(h) Protective actions. Actions are 

appropriate when the health benefit 

associated with the reduction in dose 

that can be achieved is considered to 

offset the undesirable health, economic, 

and social factors. It is the intent of 

these recommendations that, not only 

the protective actions cited for the 

Emergency PAG be initiated when the 

equivalent response levels are reached, 

but also that actions appropriate at the 

Preventive PAG be considered. This has 

the effect of reducing the period of time 

required during which the protective 

action with the greater economic and 

social impact needs to be taken. FaA 

recommends that once one or more 

protective actions are initiated, the 

action or actions continue for a 

'Sufficient time to avoid most of the 

projected dose. There is a longstandi.J!g 

FDA policy that the purposeful blending 

of adulterated food with unadulterated 

food is a violation of the Federal Food, 

Drug, and Cosmetic Act. The following 

protective actions should be considered 

for implementation when the projected 

dose equals or exceeds the appropriate 

PAG: 

(1} Preventive PAG. (i) For pasture: (a) 

Removal of lactating dairy cows from 

contaminated pasturage and 

substitution of uncontaminated stored 

feed. 

(b) Substitute source of 


uncontaminated water. 


{ii) For milk: (a) Withholding of 


contaminated milk from the market to 


allow radioactive decay of short~lived 

radionuclides. This may be achieved by 


storage of frozen fresh milk, frozen 


concentrated milk, or frozen 


concentrated milk products. 


(b) Storage for prolonged times at 

reduced temperatures also is feasible 

provided ultrahigh temperature 

pasteurization techniques are employed 

for processing (Finley, R. D., H. B. 

Warren, and R. E. Hargrove, "Storage 

Stability of Commercial Milk," journal 

ofMilk and Food Technology, 

31(12}:382-387, December 1968). 

(c) Diversion of fiuid milk for 

pro<,luction of dry whole milk, nonfat dry 

milk, butter, cheese, or evaporated milk. 

(iii) For fruits and vegetables: (a) 

Washing, brushing, scrubbing, or peeling 

to remove surface coQtamination. 

. (b) Preservation by canning, freezing, 

and dehydration or storage to permit 

radioactive decay of short-lived 

radionuclides. 

• (iv) For grains: (a Milling and (b) 

polishing. 

• (v) For other food products, processing 

tp remove surface contamination. · 

· (vi) For meat and meat products, 

intake of cesium-134 and ceaium-137 by 

an adult via the· meat pathway may 

exceed that of the milk pathway; 

therefore, levels of cesium in milk 

approaching the "response level" should 

cause surveillance and protective 

actions for meat as appropriate. 

(vii) For animal feeds" other than 

pasture, action should be an a case-bycase basis taking into consideration the 

relationship between the radionuclide 

concentration in the atlimal feed and the 

concentration of the radionuclide in 

human food. For hay and silage fed to 

lactating cows, the concentration should 

not exceed that equivalent to the 

recommendations for pasture. 

(2) Emergency PAG. Responsible 


officials should isolate food containing 


radioactivity to prevent its introduction 


into commerce and determine whether 


condemnation or another disposition is 


appropriate. Before taking this action, 


1he following factors should be 


considered: 


(i) The availability of other possible 


protective actions discussed in 


paragraph (h)(1) of these 


recommendations. 


(ii) Relative proportion of the total 


!:liet by weight represented by the item 


in question. 


(iii) The importance of' the particular 

food in nutrition and the availability of 

uncontaminated food or substitutes. 

having the same nutritional properties. 

(iv} The relative contribution of other 

foods and other radionuclides to the 

total projected dose. 

(v) The time and effort required to 


effect corrective action. 


This notice is issued under the Public 

Health Service Act (sees. 301, 310, 311, 

58 Stat. 691-693 as amended, 88 Stat. 371 

(42 U.S.C. 241, 242o, 243)} and under 

authority delegated to the Commissioner 

~f Food and Drugs {21 CFR 5.10). 

Dated: October 11. 1982.. 


'Arthur Hull Hayes, Jr., 


Commissioner ofFood andDrogs. 

(FR Doc. SZ...28595l'ilod 1o-21~ 8:45 ami 

'BILLING CODE 41110-01-M 

CHAPTER4 

Protective Action Guides for the Intermediate Phase 

(Deposited Radioactive Materials) 

4.1 Introduction 

Following a nuclear incident it 

may be necessary to temporarily 

relocate the public from areas where 

extensive deposition of radioactive 

materials has occurred until 

decontamination has taken place. This 

chapter identifies the levels of 

radiation exposure which indicate when 

relocation from contaminated property 

is warranted. 

The period addressed by this 

chapter is denoted the "intermediate 

phase. 11 This is arbitrarily defined as 

the period beginning after the source 

and releases have been brought under 

control and environmental 

measurements are available for use as 

a basis for decisions on protective 

actions and extending until these 

protective actions are terminated. This 

phase may overlap the early and late 

phases and may last from weeks to 

many months. For the purpose of dose 

projection, it is assumed to last for one 

year. Prior to this period protective 

actions will have been taken based 

upon the P AGs for the early phase. It 

is assumed that decisions will be made 

during the intermediate phase 

concerning whether particular areas or 

properties from which persons have 

been relocated will be decontaminated 

and reoccupied, or condemned and the 

occupants permanently relocated. 

These actions Will be carried out during 

the late or "recovery" phase. 

Although these Protective Action 

Guides (P AGs) were developed based 

on expected releases of radioactive 

materials characteristic of reactor 

incidents, they may be applied to any 

type of incident that can result in 

long-term exposure of the public to 

deposited radioactivity. 

P AGs are expressed in terms of 

the projected doses above which 

specified protective actions are 

warranted. In the case of deposited 

radioactivity, · the major relevant 

protective acti•;m is relocation. Persons 

not relocated (i.e., those in less 

contaminated areas) may reduce their 

dose through the application of simple 

decontamination techniques and by 

spending more time than usual in low 

exposure rate areas (e.g., indoors). 

The P AGs should be considered 

mandatory only for use in planning, 

e.g., in developing radiological 

emergency response plans. During an 

incident, because ofunanticipated local 

conditions and: constraints, professional 

judgment by responsible officials will 

be required 1 in their application. 

Situations can be envisaged, where 

contamination from a nuclear incident 

4-1 

occurs at a site or time in which 

relocation of the public, based on the 

recommended P AGs, would be 

impracticable. Conversely, under some 

conditions, relocation may be quite 

practicable at projected doses below the 

P AGs. These situations require 

judgments by those responsible for 

protective action decisions at the time 

of the incident. A discussion of the 

implementation of these PAGs is 

provided in Chapter 7. 

The PAGs for relocation specified 

in this chapter refer only to estimates 

of doses due to exposure during the 

first year after the incident. Exposure 

pathways include external exposure to 

radiation from deposited radioactivity 

and inhalation of resuspended 

radioactive materials. Protective 

Action Guides for ingestion exposure 

pathways, which also apply during the 

intermediate phase, are discussed 

separately in Chapter 3. 

Individuals who live in areas 

contaminated by long·lived 

radionuclides may be exposed to 

radiation from these materials, at a 

decreasing rate, over the entire time 

that they live in the area. This would 

be the case for those who are not 

relocated as well as for persons who 

return following relocation. Because it 

is usually not practicable, at the time 

of a decision to relocate, to calculate 

the doses that might be incurred from 

exposure beyond one year, and because 

different protective actions may be 

appropriate over such longer periods of 

time, these doses are not included in 

the dose specified in the PAGs for 

relocation. 

4.1.1 Exposure Pathways 

The principal pathways for 

exposure of the public occupying 

locations contaminated by deposited 

radioactivity are expected to be 

exposure ofthe whole body to external 

gamma radiation from deposited 

radioactive materials (groundshine) 

and internal exposure from the 

inhalation of resuspended materials. 

For reactor incidents, external gamma 

radiation is expected to be the 

dominant source. 

Almost invariably relocation 

decisions will be based on doses from 

the above pathways. (However, in rare 

cases where food or drinking water is 

contaminated to levels above the PAG 

for ingestion, and its withdrawal from 

use will create a risk from starvation 

greater than that from the radiation 

dose, the dose from ingestion should be 

added to the dose from the above 

pathways.) PAGs related specifically to 

the withdrawal of contaminated food 

and water from use are discussed in 

Chapter 3. 

Other potentially significant 

exposure pathways include exposure to 

beta radiation from surface 

contamination and direct ingestion of 

contaminated soil. These pathways are 

not expected to be controlling for 

reactor incidents (AR·89). 

4.1.2 The Population Affected 

The PAGs for relocation . are 

intended for use in establishing the 

boundary ofa restricted zone within an 

4·2 

area that has been subjected to 

deposition of radioactive materials. 

During their development, 

consideration was given to the higher 

risk of effects on health to children and 

fetuses from radiation dose and the 

higher risk to some other population 

groups from relocation. To avoid the 

complexity of implementing separate 

PAGs for individual members of the 

population, the relocation PAG is 

established at a level that will provide 

adequate protection for the general 

population. 

Persons residing in contaminated 

areas outside the restricted zone will 

be at some risk from radiation dose. 

Therefore, guidance on the reduction of 

dose during the first year to residents 

outside this zone is also provided. Due 

to the high cost ofrelocation, it is more 

practical to reduce dose in this 

·population group by the early 

application of simple, low-impact, 

protective actions other than by 

relocation. 

4.2 The Protective Action Guides for 

Deposited Radioactivity 

P AGs for protection from deposited 

radioactivity during the intermediate 

phase are surhmarized in Table 4-l. 

The basis for these values is presented 

in detail in Appendix E. In summary, 

relocation is warranted when the 

projected sum of the dose equivalent 

from external gamma radiation and the 

committed effective dose equivalent 

from inhalation of resuspended 

radionuclides exceeds 2 rem in the first 

year. Relocation to avoid exposure of 

the skin to beta radiation is warranted 

at 50 times the numerical value of the 

relocation P AG for effective dose 

equivalent. 

Persons who are not relocated, i.e., 

those in areas that receive relatively 

small amounts of deposited radioactive 

material, should reduce their exposure 

by the application of other measures. 

Possible dose reduction techniques 

range from the simple processes of 

scrubbing and/or flushing surfaces, 

soaking or plowing ofsoil, removal and 

disposal of small spots of soil found to 

be highly contaminated (e.g., from 

settlement of water), and spending 

more time than usual in lower 

exposure rate: areas (e.g., indoors), to 

the difficult. and time-consuming 

processes of :removal, disposal, and 

replacement of contaminated surfaces. 

It is anticipated that simple processes 

will be most appropriate for early 

application. Many can be carried out 

by residents themselves with support 

from response officials for assessment 

ofthe levels of.contamination, guidance 

on appropriat~ actions, and disposal of 

contaminated materials. Due to the 

relatively low. cost and risk associated 

with these protective actions, they may 

be justified as ALARA measures at low 

dose levels. It is, however, 

recommended; that response officials 

concentrate theirinitial efforts in areas 

where the projected dose from the first 

year of exposure exceeds 0.5 rem. In 

addition, first priority should be given 

to cleanup of residences of pregnant 

women who may exceed this criterion. 

4-3 

Table 4-1 Protective Action Guides for Exposure to Deposited Radioactivity 


During the Intermediate Phase of a Nuclear Incident 


Protective P AG (projected Comments 

Action dose)a 

Relocate the general ;:;:2rem Beta dlose to skin may be 

population.h up to 50 times higher 

Apply simple dose <2rem These protective actions 

reduction techniques. c should be taken to reduce 

doses to as low as 

practicable levels. 

NJ.'he projected sum of effective dose equivalent from external gamma radiation and committed 

effective dose equivalent from inhalation of resuspended materials, from exposure or intake during 

the first year. Projected dose refers to the dose that would be received in the absence of shielding 

from structures or the application of dose reduction techniques. These PAGs may not provide 

adequate protection from some long-lived radionuclides (see Section 4.2.1). 

bPersons previously evacuated from areas outside the relocation zone defined by this PAG may 

return to occupy their residences. Cases involving relocation of persons at high risk from such 

action (e.g., patients under intensive car.e) should be evaluated individually. 

csimple dose reduction techniques include scrubbing and/or flushing hard surfaces, soaking or 

plowing soil, minor removal of soil from spots where radioactive materials have concentrated, and 

spending more time than usual indoors or in other low exposure rate areas. 

4.2.1 Longer Term Objectives of the 

Protective Action Guides 

It is an objective of these PAGs to 

assure that 1) doses in any single year 

after the first will not exceed 0.5 rem, 

and 2) the cumulative dose over 50 

years (including the first and second 

years) will not exceed 5 rem. For 

source terms from reactor incidents, 

the above P AG of 2 rem projected dose 

in the first year is expected to meet 

both of those objectives through 

radioactive decay, weathering, and 

normal part time occupancy in 

structures. Decontamination of areas 

outside the restricted area may be 

required during the first year to meet 

these objectives for releases consisting 

primarily of long-lived radionuclides. 

For situations where itis impractical to 

meet these objectives though 

decontamination, consideration should 

be given to relocation at a lower 

projected first year dose than that 

specified by the relocation PAG. 

4-4 

After the population has been 

protected in accordance with the P AGs 

for relocation, return for occupancy of 

previously restricted areas should be 

governed on the basis of Recovery 

Criteria as presented in Chapter 8. 

Projected dose considers exposure 

rate reduction from radioactive decay 

and, generally, weathering. When one 

also considers the anticipated effects of 

shielding from partial occupancy in 

homes and other structures, persons 

who are not relocated should receive a 

dose substantially less than the 

projected dose. For commonly assumed 

reactor source terms, we estimate that 

2 rem projected dose in the first year 

will be reduced to about 1.2 rem by 

this factor. The application of simple 

decontamination techniques shortly 

after the incident can be assumed to 

provide a further 30 percent or more 

reduction, so that the maximum frrst 

year dose to persons who are not 

relocated is expected to be less than 

one rem. Taking account ofdecay rates 

assumed to be associated with releases 

from nuclear power plant incidents 

(SN-82) and shielding from partial 

occupancy and weathering, a projected 

dose of 2 rem in the first year is likely 

to amount to an actual dose of 0.5 rem 

or less in the second year and 5 rem or 

less in 50 years. The application of 

simple dose reduction techniques would 

reduce these doses further. Results of 

calculations supporting these 

projections are summarized in Table 

E-6 of Appendix E. 

4.2.2 Applying the Protective Action 

Guides for Relocation 

Establishing the boundary of a 

restricted zone may result in three 

different types of actions: 

1. 	Persons who, based on the P AGs for 

the early phase of a nuclear incident 

(Chapter 2), have already been 

evacuated from an area which is now 

designated as a restricted zone must 

be converted to relocation status. 

2. 	 Persons not previously evacuated 

who reside inside the restricted zone 

should relocate. 

3. 	 Persons who normally reside 

outside the restricted zone, but were 

previously evacuated, may return. A 

gradual return is recoinmended, as 

discussed in Chapter 7. 

Small adj-Q.stments to the boundary 

of the restricted zone from that given 

by the PAG may be justified on the 

basis of difficulty or ease . of 

implementatiO::n. For example, the use 

of a convenient natural boundary could 

be cause for adjustment of the 

restricted zop.e. However, such 

decisions should be supported by 

demonstration that exposure rates to 

persons not relocated can be promptly 

reduced by ' methods other than 

relocation to n;1eet the PAG, as well as 

the longer term dose objectives 

addressed in Section 4.2.1. 

Reactor , incidents involving 

releases of major portions of the core 

inventory under adverse atmospheric 

conditions can, be postulated for which 

4-5 

large areas would have to be restricted 

under these PAGs. As the affected 

land area increases, they will become 

more difficult and costly to implement, 

especially in densely populated areas. 

For situations where implementation 

becomes impracticable or impossible 

(e.g., a large city), informed judgment 

must be exercised to assure priority of 

protection for individuals in areas 

having the highest exposure rates. In 

such situations, the first priority for 

any area should be ·to reduce dose to 

pregnant women. 

4.3 Exposure Limits for Persons 

Reentering the Restricted Zone 

Individuals who are permitted to 

reenter a restricted zone to work, or for 

other justified reasons, will require 

protection from radiation. Such 

individuals should enter the restricted 

zone under controlled conditions in 

accordance with dose limitations and 

other procedures for control of 

occupationally-exposed workers 

(EP-87). Ongoing doses received by 

these individuals from living in a 

contaminated area outside the 

restricted zone need not be included as 

part of this dose limitation applicable 

to workers. In addition, dose received 

previously from the plume and 

associated groundshine, during the 

early phase of the nuclear incident, 

need not be considered. 

References 

AR-89 Aaberg, Rosanne, Evaluation of Skin 

and Ingestion Exposure Pathways. EPA 

520/1-89-016. U.S. Environmental Protection 

Agency, Washington, (1989). 

EP-87 U.S. Environmental Protection Agency. 

Radiation Protection Guidance to Federal 

Agencies for Occupational Exposure. Federal 

Register, .§.g, 2822; January 27, 1987. 

SN-82 Sandia National Laboratory. Technical 

Guidance for Siting Criteria Development. 

NUREG/CR-2239. U.S. Nuclear Regulatory 

Commission, Washington, (1982). 

4-6 

CHAPTERS 

Implementing the Protective Action Guides 

for the Early Phase 

5.1 Introduction 

This chapter provides general 

guidance for implementing the 

Protective Action Guides (PAGs) set 

forth in Chapter 2. In particular, the 

objective is to provide guidance for 

estimating projected doses from 

exposure to an airborne plume of 

radioactive material, and for choosing 

and implementing protective actions. 

Following an incident which has the 

potential for an atmospheric release of 

radioactive material, the responsible 

State and/or local authorities will need 

to decide whether offsite protective 

actions are needed and, if so, where 

and when they should be implemented. 

These decisions will be based primarily 

on (a) the potential for releases, (b) 

projected doses as a function oftime at 

various locations in the environment, 

and (c) dose savings and risks 

associated with various protective 

actions. 

Due to the wide variety of nuclear 

facilities, incidents, and releases that 

could occur, it is not practical to 

provide specific implementingguidance 

for all situations. Examples of the 

types of sources leading to airborne 

releases that this guidance may be 

applied to are nuclear power reactors, 

uranium fuel cycle facilities, nuclear 

weapons facilities, radiopharmaceutical 

manufacturers and users, space vehicle 

launch and reentry, and research 

reactors. For many specific 

applications, . however, it will be 

appropriate to develop and use 

implementing procedures that are 

designed for use on a case-by-case 

basis. 

Dose conversion factors (DCF) and 

derived response levels (DRL) are 

provided for radionuclides that are 

most likely to be important in an 

incident involving an airborne release 

of radioactive materials. DCFs and 

DRLs for radionuclides not listed may 

be developed from the sources referenced in the tables. The values 

provided here are the best currently 

available. However, as new information is developed these values may 

change. This chapter will be revised 

from time to time to reflect such 

changes. 

5.2 Initial Response and Sequence of 

Subsequent Actions 

In the case of an atmospheric 

release, the protective actions which 

may be required are those which protect the population from inhalation of 

radioactive materials in the plume, 

from exposure to gamma radiation 

5-1 

from the plume, and from short-term 

exposure to radioactive materials 

deposited on the ground. For releases 

which contain a large amount of pure 

beta emitters, it may also be necessary 

to consider protective action to avoid 

doses to the skin from radioactive 

material deposited on the skin and 

clothing. 

The early phase can be divided into 

two periods: (a) the period immediately following the start of an incident 

(possibly before a release has occurred), 

when little or no environmental data 

are available to confirm the magnitude 

of releases, and (b) the subsequent 

period, when environmental or source 

term measurements permit a more 

accurate assessment ofprojected doses. 

During the first period, speed in 

completing such actions as evacuating, 

sheltering, and controlling access may 

be critical to minimizing exposure. 

Environmental measurements made 

during this period may have limited 

use because of the lack of availability 

of significant data and uncertainty 

about changes in environmental 

releases of radioactive material from 

their sources. In the case of a facility, 

for example, the uncertainty might be 

due to changes in pressure and 

radionuclide concentrations within the 

structures from which the plume is 

being released. Therefore, it is 

advisable to initiate early protective 

actions in a predetermined manner 

that is related to facility conditions. 

This will normally be carried out 

through recommendations provided by 

the facility operator. During the 

second period, when environmental 

levels are known, these actions can be 

adjusted as necessary. 

For an incident at a facility 

involving significant potential for an 

atmospheric release with offsite 

consequences, the following sequence of 

actions is appropriate: 

1. Notification of State and/or local 

authorities by the facility operator that 

conditions are such that a release is 

occurring, or could occur with offsite 

consequences. For severe incidents 

(e.g., general emergencies) the operator 

should provide protective action 

recommendations to State and local 

authorities.1 

2. For emergencies with the potential 

for offsite consequences, immediate 

evacuation (and/or sheltering) of 

populations in predesignated areas 

without waiting for release rate 

information or environmental 

measurements. 

3. Monitoring of facility conditions, 

release rates, environmental concentrations, and exposure rates. 

1

In the case of commercial nuclear power 

plants, fuel facilities and certain material 

facilities licensed by the NRC, regulations (NR89) require that the facility operator have the 

capability to notify predesignated State and/or 

local authorities within 15 minutes of any 

emergency declaration. The initial notification 

message .to State and/or local officials for any 

General Emergency declaration must include a 

protective action recommendation. 

5-2 

4. Estimation of offsite consequences 

(e.g., calculation of the plume 

centerline dose rates and projected 

doses at various distances downwind 

from the release point). 

5. Implementation of protective 

actions in additional areas if needed. 

6. Decisions to terminate existing 

protective actions should include, as a 

minimum, consideration of the status 

of the plant and the PAGs for 

relocation (Chapter 4). (Withdrawal of 

protective actions from areas where 

they have already been implemented is 

usually not advisable during the early 

phase because of the potential for 

changing conditions and confusion.) 

For other types of incidents the 

sequence ofactions may varyin details, 

depending on the specific emergency 

response plan, but in general the 

sequence and general reporting 

requirements will be the same. 

5.2.1 Notification 

The nuclear facility operator or 

other designated individual should 

provide the first notification to State 

and/or local authorities that a nuclear 

incident has occurred. In the case of 

an incident with the potential for 

offsite consequences, notification of 

State and local response organizations 

by a facility operator should include 

recommendations, based on plant 

conditions, for early evacuation and/or 

sheltering in predesignated areas. 

Early estimates of the various 

components of projected doses to the 

population at the site boundary, as well 

as at more distant locations, along with 

estimated time frames, should be made 

as soon as the relevant source or 

release data become available. 

Emergency response planners should 

make ·arrangements with the facility 

operator to assure that this 

information will be made available on 

a timely basis and that dose projections 

will be provided in units that can be 

directly compared to the PAGs. 

Planners should note that the toxic 

chemical hazard is greater than the 

radiation hazard for some nuclear 

incidents, e.g. a uranium hexafluoride 

release. 

Forsome incidents, such as re-entry 

of satellites or an incident in a foreign 

country, notification is most likely to 

occur through the responsible Federal 

agency, most commonly the 

Environmental Protection Agency or 

the National Aeronautics and Space 

Administration. In such cases 

projections of dose and 

recommendations to State and local 

officials for protective actions will be 

made at the Federal level, under the 

Federal Radiological Emergency 

Response Plan (FE-85). 

5.2.2 Immediate Protective Action 

Guidance for developing emergency 

response plans for implementation of 

immediate protective actions for 

incidents at commercial nuclear power 

plants is contained in NUREG-0654 

(NR-80). Planninf elements for 

5-3 

incidents at other types of nuclear 

facilities should be developed using 

similar considerations. Information on 

the offsite consequences of accidents 

that can occur at commercial fuel cycle 

and material facilities licensed by the 

NRC can be found in NUREG-1140 

(NR-88). The "Planning Basis for the 

Development of State and Local 

Government Radiological Emergency 

Response Plans in Support of Light 

Water Nuclear Power Plants" (NR-78) 

recommends that States designate an 

emergency planning zone (EPZ) for 

protective action for plume exposure 

(see Chapter 2). Within this zone, an 

area should be predesignated for 

immediate response based on specified 

plant conditions prior to a release, or, 

given a release, prior to the availability 

of information on quantities of 

radioactive materials released. The 

shape of this area will depend on local 

topography and political and other 

boundaries. Additional areas in the 

balance of the EPZ, particularly in the 

downwind direction, may also require 

evacuation orsheltering, as determined 

by dose projections. The size of these 

areas will be based on the .potential 

magnitude of the release, and of an 

angular spread determined by 

meteorological conditions and any other 

relevant factors. 

The predesignated areas for 

immediate protective action may be 

reserved for use only for the most 

severe incidents and where the facility 

operator cannot provide a quick 

estimate of projected dose based on 

actual releases. For lesser incidents, or 

ifthe facility operator is able to provide 

prompt offsite dose projections, the 

area for immediate protective action 

may be specified at the time of the 

incident, in lieu of using a 

predesignated area. 

Such prompt offsite dose projections 

may be possible when the facility 

operator can estimate the potential 

offsite dose, based on information at 

the facility, using relationships 

developed during planning that relate 

abnormal plant conditions and 

meteorological conditions to potential 

offsite doses. After the release starts 

and the release rate is measurable 

and/or when plant conditions or 

measurements can be used to estimate 

the characteristics of the release ,and 

the release rate as a function of time, 

then these factors, along with 

atmospheric stability, windspeed, and 

wind direction, can be used to estimate 

integrated concentrations ofradioactive 

contamination as a function oflocation 

downwind. Although such projections 

are useful for initiating protective 

action, the accuracy of these methods 

for estimating projected dose will be 

uncertain prior to confirmatory field 

measurements because of unknown or 

uncertain factors affecting 

environmental pathways, inadequacies 

of computer modeling, and uncertainty 

in the data for release terms. 

5.3 The Establishment of Exposure 

Patterns 

During and immediately following 

the early response to a nuclear 

incident, sufficient environmental 

5-4 

naeasurenaents are ur.Uikely to be 

available to project doses accurately. 

Doses naust be projected· using initial 

environmental measurements or 

estimates ofthe sot.rrce terna, and using 

atmospheric transport previously 

observed under similar meteorological 

conditions. These projections are 

needed to determine whether protective 

actions shoUld be implemented in 

additional areas during the early 

phase. 

Source terna measurements, or 

exposure rates or concentrations 

naeasured in the plume at a few 

selected locations, naay be used to 

.estimate the extent ofthe exposed area 

in a variety of ways, depending on the 

types ofdata and computation naethods 

available. The most accurate naethod 

·of projecting doses is through the use of 

an atmospheric diffusion and transport 

naodel that has been verified for use at 

the site in question. A variety of 

conaputer software can he used to 

estimate exposures in real time, or to 

extrapolate a series of previouslyprepared isopleths for unit releases 

under various meteorological 

conditions. The latter can be adjusted 

for the estinaated source naagnitude or 

environmental naeasurements at a few 

locations during the incident. If the 

model projections have sonae semblance 

of consistency with environmental 

naeasurements, extrapolation to other 

distances and areas can be naade with 

greater confidence. Ifprojections using 

a sophisticated site-specific model are 

not available, a simple, but crude, 

method is to measure the plume centerline exposure rate2 at ground level 

(approximately one meter height) at a 

known distance downwind of the 

release point and then to calculate 

exposure rates at other downwind 

locations by assuming that the plume 

centerline exposure rate is a known 

function of the distance from the 

release point. 

The following relationship can be 

used for this calculation: 

where D1 and D2 are naeasurenaents of 

exposure rates at the centerline of the 

plume at distances and R2 R , 1 

respectively, andy is a constant that 

depends on atmospheric stability. For 

stability classes A and B, y = 2; for 

stability classes C and D, y =1.5; and 

for stability classes E and F, y = 1. 

Classes A and B (unstable) occur with 

light winds and strong sunlight, and 

classes E and F (stable) with light 

winds at night. Classes C and D 

generally occur with winds stronger 

than about 10 naph. This naethod of 

extrapolation is risky because the 

measurements available at the 

reference distance may be 

unrepresentative, especially if the 

plume is aloft and has a looping 

2

The centerline exposure rate can be 

determined by traversing the plume at a point 

sufficiently far downwind that it has stabilized 

(usually more than one mile from the release 

point) while taking continuous exposure rate 

measurements. 

5-5 

behavior. In the case of an elevated 

plume, the grotmd level concentration 

increases with distance from the 

source, and then decreases, whereas 

any high energy gamma radiatio: ..om 

the overhead cloud . continuously 

decreases with distance. For these 

reasons, this method of extrapolation 

will perform bestfor surface releases or 

if the point of measurement for an 

elevated release is sufficiently distant 

from the point ofrelease for the plume 

to have expanded to ground level 

(usually more than one mile). The 

accuracy of this method will be 

improved by the use of measurements 

from many locations averaged over 

time. 

5.4 Dose Projection 

The PAGs set forth in Chapter 2 

are specified in terms of the effective 

dose equivalent. This dose includes 

that due to external gamma exposure 

of the whole body, as well as the 

committed effective dose equivalent ­

from inhaled radionuclides. Guidance 

is also provided on protective action 

levels for the thyroid and skin, in 

terms ofthe committed dose equivalent 

to these organs. Further references to 

effective or organ dose equivalent refer 

to these two quantities, respectively. 

Methods for estimating projected doses 

for each ofthese forms of exposure are 

discussed below. These require 

knowledge of, or assumptions for, the 

intensity and duration of exposure and 

make use of standard assumptions on 

the relation, for each radioisotope, 

between exposure and dose. Exposure 

and dose projections should be based 

on the best estimates available. · The 

methods and models used here may be 

modified as necessary for specific sites 

to achieve improved accuracy. 

5.4.1 Duration of Exposure 

The projected dose for comparison 

to the early phase PAGs is normally 

calculated for exposure during the first 

four days following the projected (or 

actual) start of a release. The objective 

is to encompass the entire period of 

exposure to the plume and to deposited 

material priorto implementation ofany 

further, longer~term protective action, 

such as relocation. Four days is chosen 

here as the dw.·ation of exposure to 

deposited materials during the early 

phase because, for planning purposes; 

it is a reasonable estimate of the time 

needed to make measurements, reach 

decisions, and prepare to implement 

relocation. However, officials at the 

site at the time of the emergency may 

decide that a. different time is more 

appropriate. Corresponding changes to 

the dose conversion factors found in 

tables in Section 5.4.2 will be needed if 

another exposure I>eriod is selected. 

Protective actions are taken to 

avoid or reduce projected doses. Doses 

incurred before the start of the 

protective action being considered 

should not normally be included in 

evaluating the need for protective 

· 	action. Likewise, doses that may be 

incurred at later times than those 

affected by ·the specific protective 

action should not be included. For 

5~6 
example, doses which may be incurred 

through ingestion pathways or 

long-term exposure to deposited 

radioactive materials take place over a 

different, longer time period. 

Protective actions for such exposures 

should be based on guidance addressed 

in other chapters. 

The projected dose from each · 

radionuclide in a plume is proportional 

to the time-integrated concentration of 

the radionuclide in the plume at each 

location. This concentration will 

depend on the rate and the duration of 

the release and meteorological 

conditions. Release rates will vary 

with time, and this time-dependence 

ca~not usually be predicted accurately. 

In the absence o~ more specific 

information, the release rate may be 

assumed to be constant. 

Another factor affecting the 

estimation of projected dose is the 

duration of the plume at a particular 

location. For purposes of calculating 

projected dose from most pathways, 

exposure will start at a particular 

location when the plume arrives and 

end when the plume is no longer 

present, due either to an end to the 

release, or a change in wind direction. 

Exposure from one pathway (whole 

body exposure to deposited materials) 

will continue for an extended period. 

Other factors such as the aerodynamic 

diameter and solubility of particles, 

shape of the plume, and terrain may 

also affect estimated dose, and may be 

considered on a site- and/or sourcespecific basis. 

Prediction of time frames for 

releases is difficult because ofthe wide 

range associated with the spectrum of 

potential incidents. Therefore, 

planners should consider the possible 

time periods between an initiating 

event and arrival of a plume, and the 

duration of releases in relation to the 

time needed to implement competing 

protective actions (i.e., evacuation and 

sheltering). Analyses of nuclear power 

reactors (NR-75) have shown that some 

incidents may take several days to 

develop to the point of a :release, while 

others may begin as early as one-half 

hour after an initiating · event. 

Furthermore, the duration of a release 

may range from less than one hour to 

several days, with the major portion of 

the release usually occurring within 

the first day. 

Radiological exposure rates are 

quite sensitive to the wind speed. The 

air concentration is inversely related to 

the wind speed at the point of release. 

Concentrations are also affected by the 

turbulence of the air, which tends to 

increase with wind speed and sunlight, 

and bymeandering ofthe plume, which 

is greater at the lower wind speeds. 

This results in higher concentrations 

generally being associated with low 

winds near the source, 'and with 

moderate winds at larger distances. 

Higher windspeed also shortens the 

travel time. Planning information on 

time frames for releases from· nuclear 

power facilities· may be found in 

Reference NR-78. Time frames for 

releases from other facilities will 

depend on the characteristics of the 

facility. · 

5-7 

Since a change in wind direction 

will also affect the duration of 

exposure, it is very important that 

arrangements be made for a public, 

private, or military professional 

weather service to provide information 

on current meteorological and wind 

conditions and predicted wind direction 

persistence during an incident, in 

addition to information received from 

the facility operator. 

5.4.2 Dose Conversion Factors 

This section provides dose 

conversion factors (DCFs) and derived 

response levels (DRLs) for those 

radionuclides important for responding 

to most types of incidents. These are 

supplemented by an example to 

demonstrate their application. The 

DCFs are useful where multiple 

radionuclides are involved, because the 

total dose from a single exposure 

pathway will be the sum of the doses 

calculated for each radionuclide. The 

DRLs are surrogates for the PAG and 

are directly usable for releases 

consisting primarily ofa single nuclide, 

in which case the DRL can be 

compared directly to the measured or 

calculated concentration. (DRLs also 

can be used for multiple radionuclides 

by summing the ratios of the 

environmental concentration of each 

nuclide to its respective DRL. To meet 

the PAG, this sum must be equal to or 

less than unity.) 

DCFs and DRLs for each of the 

three major exposure pathways for the 

early phase (external exposure to 

plume, plume inhalation, and external 

exposure from deposited materials) are 

provided separately in Section 5.6. 

They are all expressed in terms of the 

time-integrated air concentration at the 

receptor so they can be conveniently 

summed over the three exposure 

pathways to obtain composite DRLs 

and DCFs for each radionuclide. These 

composite values are tabulated in Table 

5-1 for effective dose and in Table 5-2 

for thyroid dose from inhalation of 

radioiodines. 

The tabulated DCFs and DRLs 

include assumptions on particle size, 

deposition velocity, the presence of 

short-lived daughters, and exposure 

duration as noted. The existence of 

more accurate data for individual 

radionuclides may justify modification 

of the DCFs and DRLs. The 

procedures described in Section 5:6 for 

developing the DCFs and DRLs for 

individual exposure pathways may be 

referred to, to assist such 

modifications. 

To apply Tables 5-l and 5-2 to 

decisions on implementing PAGs, one 

may use either the DCFs or DRLs. 

DCFs are used to calculate the 

projected composite dose for each 

radionuclide; these doses are then 

summed and compared to the PAG. 

The DRLs may be used by summing 

the ratios of the concentration of each 

radionuclide to its corresponding DRL. 

If the sum of the ratios exceeds unity, 

the corresponding protective action 

should be initiated. 

5-8 

Table 5-1 Dose Conversion .Factors (DCF) and Derived Response Levels (DRL) for 

Combineda Exposure Pathways During the Early Phase of a Nuclear 

Incidentb 

Radionuclide 

H-3 


C-14 


Na-22 


Na-24 


P-32 


P-33 


S-35 


Cl-36 


K-40 


K-42 


Ca-45 


Sc-46 


Ti-44 


V-48 


Cr-51 


Mn-54 

Mn-56 

Fe-55 

Fe-59 

Co-58 

Co-60 


Ni-63 


Cu-64 


Zn-65 


Ge-68 


Se-75 

Kr-85 

Kr-85m 

Kr-87 

Kr-88 

DCF 


rem per 
 c· -a h
 Jll'CID • 

7.7E+01 

2.5E+03 

1.9E+04 

7.3E+03 

1.9E+04 

2.8E+03 

3.0E+03 

2.6E+04 

1.6E+04 

2.0E+03 

8.0E+03 

4.4E+04 

1.2E+06 

2.4E+04 

5.5E+02 

1.2E+04 

1.8E+03 

3.2E+03 

2.3E+04 

1.7E+04 

2.7E+05 

7.6E+03 

5.9E+02 

2.7E+04 

6.2E+04 

1.2E+04 

1.3E+00 

9.3E+01 

5.1E+02 

1.3E+03 

DRLC 


JICi · cm·3 • h 


1.3E-02 

4.0E-04 

5.3E-05 

1.4E-04 

5.4E-05 

3.6E-04 

3.4E-04 

3.8E-05 

6.5E-05 

5.1E-04 

1.3E-04 

2.3E-05 

8.2E-07 

4.2E-05 

1.8E-03 

8.5E-05 

5.7E-04 

3.1E-04 

4.4E-05 

5.7E-05 

3.7E-06 

1.3E-04 

1.7E-03 

3.7E-05 

1.6E-05 

8.3E-05 

7.8E-01 

1.1E-02 

2.0E-03 

7.8E-04 

5-9 

Radionuclide 

Kr-89 

Rb-86 

Rb-88 

Rb-89 

Sr-89 

Sr-90 

Sr-91 

Y-90 

Y-91 

Zr-93 

Zr-95 

Zr-97 

Nb-94 

Nb-95 

Mo-99 

Tc-99 

Tc-99m 

Ru-103 

Ru-105 

Ru/Rh-106d 

Pd-109 

Ag-110m 

Cd-109 

Cd-113m 

In-114m 

Sn-113 

Sn-123 

Sn-125 

Sn-126 

Sb-124 

Table 5-l, Continued 

DCF DRLC 

rem per J.ICi · cm·3 • h 

J.ICi · cm·3 • h 

1.2E+03 8.6E-04 

8.3E+03 1.2E-04 

5.2E+02 1.9E-03 

1.4E+03 7.3E-04 

5.0E+04 2.0E-05 

1.6E+06 6.4E-07 

2.4E+03 · 4.2E-04 

1.0E+04 9.9E-05 

5.9E+04 1.7E-05 

3.9E+05 2.6E-06 

3.2E+04 3.2E-05 

5.5E+03 1.8E-04 

5.0E+05 2.0E-06 

1.0E+04 9.7E-05 

5.2E+03 1.9E-04 

1.0E+04 1.0E-04 

1.7E+02 6.0E-03 

1.3E+04 7.7E-05 

1.2E+03 8.2E-04 

5.7E+05 1.7E-06 

1.3E+03 7.6E-04 

9.8E+04 l.OE-05 

1.4E+05 7.3E-06 

1.8E+06 5.5E-07 

1.1E+05 9.4E-06 

1.3E+04 7.8E-05 

3.9E+04 2.6E-05 

2.0E+04 5.1E-05 

1.2E+05 8.4E-06 · 

3.8E+04· 2.6K-05 

5-10 

Radionuclide 

Sb-126 

Sb-127 

Sb-129 

Te-127m 

Te-129 

Te-129m 

Te-131m 

Te-132 

Te/I-132d 

Te-134 

I-125 

I-129 

I-131 

I-132e 

I-133 

I-134 

I-135 

Xe-131m 

Xe-133 

Xe-133m 

Xe-135 

Xe-135m 

Xe-137 

Xe-138 

Cs-134 

Cs-136 

Cs/Ba-137d 

Cs-138 

Ba-133 

Ba-139 

Table 5-l, Continued 

DCF. DRLC 

rem per p.Ci · cm·3 • h 

p.Ci · cm·3 • h 

2.6E+04 3.9E-05 

9.5E+03 1.1E-04 

2.0E+03 5.0E-04 

2.6E+04 3.9E-05 

1.4E+02 7.0E-03 

2.9E+04 3.5E-05 

8.6E+03 1.2E-04 

1.2E+04. 8.5E-05 

2.0E+04 5.0E-05 

7.0E+02 1.4E-03 

3.0E+04 3.3E-05 

2.1E+05 4.8E-06 

5.3E+04 1.9E-05 

4.9E+03 2.0E-04 

1.5E+04 6.8E-05 

3.1E+03 3.3E-04 

8.1E+03 1.2E-04 

4.9E+00 2.0E-01 

2.0E+01 5.0E-02 

1.7E+01 5.9E-02 

1.4E+02 · 7.0E-03 

2.5E+02 4.1E-03 

1.1E+02 9.3E-03 

7.2E+02 1.4E-03 . 

6.3E+04 1.6E-05 

1.8E+04 5.6E-05 

4.1E+04 2.4E-05 

1.6E+03 6.1E-04 

1.1E+04 8.9E-05 

2.3E+02 4.4E-03 

5-11 
Radionuclide 

Ba-140 

La-140 

La-141 

La-142 

Ce-141 

Ce-143 

Ce-144 

Ce/Pr-144d 

Nd-147 

Pm-145 

Pm-147 

Pm-149 

Pm-151 

Sm-151 

Eu-152 

Eu-154 

Eu-155 

Gd-153 

Tb-160 

Ho-166m 

Tm-170 

Yb-169 

Hf-181 

Ta-182 

W-187 

Ir-192 

Au-198 

Hg-203 

Tl-204 

Pb-210 

Table 5-1, Continued 

DCF DRLC 

rem per pCi · cm·3 • h 

pCi · cm"3 • h 

5.3E+03 1.9E-04, 

1.1E+04 8.8E-05 

7.3E+02 1.4E-03 

2.3E+03 4.3E-04 

1.1E+04 9.0E-05 

4.7E+03 2.1E-04 

4.5E+05 2.2E-06 

4.5E+05 2.2E+06 

8.8E+03 1.1E-04 

3.7E+04 2.7E-05 

4.7E+04 2.1E-05 

3.6E+03 2.8E-04 

2.8E+03 3.5E:-04 

3.6E+04 2.8E-05 

2.7E+05 3.8E-06 

3.5E+05 2.9E-06 

5.0E+04 2.0E-05 

2.9E+04 3.4E-05 

3.5E+04 2.9E-05 

9.4E+05 1.1E-06 

3.2E+04 3.2E-05 

1.1E+04 8.9E-05 

2.1E+04 4.8E-05 

6.0E+04 1.7E-05 

1.7E+03 6.0E-04 

3.8E+04 2.7E-05 

5.2E+03 1.9E-04 

9.9E+03 1.0E-04 

2.9E+03 3.5E-04 

1.6E+07 6.1E-08 

5-12 

Table 5-1, Continued 

DCF DRLC 

Radionuclide rem per p.Ci · cm·3 • h 

p.c·1·cm.g · h 

Bi-207 3.1E+04 3.2E-05 

Bi-210 1.9E+04 5.3E-05 

Po-210 1.1E+07 8.9E-08 

Ra-226 1.0E+07 9.7E-08 

Ac-227 8.0E+09 1.2E-10 

Ac-228 3.7E+05 2.7E-06 

Th-227 1.9E+07 5.2E-08 

Th-228 4.1E+08 2.4E-09 

Th-230 3.9E+08 2.6E-09 

Th-232 2.0E+09 5.1E-10 

Pa-231 1.5E+09 6.5E-10 

U-232 7.9E+08 1.3E-09 

U-233 1.6E+08 6.2E-09 

U-234 1.6E+08 6.3E-09 

U-235 1.5E+08 6.8E-09 

U-236 1.5E+08 6.6E-09 

U-238 1.4E+08 7.0E-09 

U-240 2.7E+03 3.7E-04 

Np-237 6.5E+08 1.5E-09 

~p-239 3.6E+03 2.8E-04 

Pu-236 1.7E+08 5.8E-09 

Pu-238 4.7E+08 2.1E-09 

Pu-239 5.2E+08 1.9E-09 

Pu-240 5.2E+08 1.9E-09 

Pu-241 9.9E+06 l.OE-07 

Pu-242 4.9E+08 2.0E-09 

Am-241 5.3E+08 1.9E-09 

Am-242m 5.1E+08 2.0E-09 

Am-243 5.3E+08 1.9E-09 

Cm-242 2.1E+07 4.8E-08 

5-13 
Table 5-1, Continued 

DCF 

Radionuclide rem per 

pCi · cm·3 • h 

Cm-243 3.7E+08 2.7E-09 

Cm-244 3.0E+08 3.4E-09 

Cm-245 5.5E+08 1.8E-09 

Cm-246 5.4E+08 1.9E-09 

Cf-252 1.9E+08 5.3E-09 

•sum of doses from external exposure and inhalation from the plume, aud external exposure .from 

deposition. "Dose" means the sum of effective dose equivalent from external radiation and committed 

effective dose equivalent from intake. · 

bSee footnote a to Table 5-4 for assumptions on inhalation and footnote b to Table 5-5 for assumptions 

on deposition velocity. The quantity }lCi- cm·3 

- h refers to the time-integrat1~d air concentration at one 

meter height. 

Tor 1 rem committed effective dose equivalent. 

wrhe contribution from the short-lived daughter is included in the factors for the parent radionuclide. 

orrhese factors should only be used in situations where 1-132 appears without the parent radionuclide. 

Persons exposed to an airborne 

particulate plume will receive dose to 

skin from beta emitters in the plume 

as well as from those deposited on skin 

and clothing. Although it is possible to 

detect beta radiation, itis not practical, 

for purposes of decisions on evacuation 

and sheltering, to determine dose to 

skin by field measurement. of the beta 

dose equivalent rate near the skin 

surface. Such doses are determined 

more practically through calculations 

based on time-integrated air 

concentration, an assumed deposition 

velocity, and an assumed time period 

between deposition and skin 

decontamination. For. the purpose of 

evaluating the relative importance .of 

skin dose compared to the dose from 

external gamma exposure and 

inhalation, dose conversion factors 

were evaluated using a deposition 

velocity of 1 em/sec and an exposure 

time before decontamination of 12 

hours. Using these conservative 

assumptions, it was determined that 

skin beta dose should seldom, if ever, 

be a controlling pathway during the 

early phase. Therefore, no DCFs or 

DRLs are listed for skin beta dose. 

5-14 

Table 5-2 Dose Conversion Factors (DCF) and Derived Response Levels (DRL) 

Corresponding to a 5 rem Dose Equivalent to the Thyroid from Inhalation 

of Radioiodine 

DCF DRLa 


Radionuclide rem per JICi · cm·3 • h 


JICi · cm·3 • h 


Te/I-132b 2.9E+05 1.8E-05 


1-125 9.6E+05 5.2E-06 


1-129 6.9E+06 7.2E-07 


1-131 1.3E+06 3.9E-06 


I-132· ·7.7E+03 6.5E-04 


1-133 2.2E+05 2.3E-05 


1-134 1.3E+03 3.9E-03 


1-135 3.8E+04 , 1.3E-04 


aFor a 5 rem committed dose equivalent to the thyroid. 

wrhe contribution from the short-lived daughter is included in the factors for the parent radionuclide. 

Because of large uncertainties in 

the assumptions for deposition, air 

concentrations are an inadequate basis 

for decisions on the need to 

decontaminate individuals. . Field 

measurements should be used for t:Ws 

(See Chapter 7, Section 7 .6.3.). It 

should b~ noted that, even in situations 

where the skin beta.dose might exceed 

50 rem, evacuation woUld not usually 

be the appropriate protective action, 

because skin · decontamination and 

clothing ch~ges are easily available 

and effective. However, ·evacuation 

would usually already be justified in 

these situations due to .. dose from 

inhalation. during pllline passage. 

The following example demonstrates 

the use ofthe data in Tables 5-l and 5­

2 for a simple analysis involving three 

radionuclides. 

. Based on source term and 

meteorological considerations, it is 

assumed that the worst probable 

nuclear. incident at an industrial 

facility is a fire that could disperse 

radioactive material into the. 

atmosphere, yielding a time-integrated 

concentration of radionuclides at a 

nearby populated area, as follows: 

Radionuclide 

Zr-95 

Cs-134 

. 1-131 

· c· -a h U I·Cm · 

2E-6 

4E-8 

l.2E-5 

5-15 

We examine whether evacuation is 

warranted at these levels,· based on 

P AGs of 1 rem for effective dose and 5 

rem for dose to the thyroid. We use 

the DCFs in Table 5-1 for effective dose 

and Table 5-2 for thyroid dose from 

inhalation of radioiodines to calculate 

the relevant doses, H, as follows: 

to avoid exceeding the P AG for thyroid 

dose. 

To use the DRLs from Table 5-l 

and 5-2, imd the sum, 

}:: ci 

1 DRLi 

11 

H = E ncFi x ci 

1 

where DCFi = dose conversion 

factor for 

radionuclide i, 

ci =	time-integrated 

concentration of 

radionuclide i, 

and n = the number of 

radionuclides 

present.. 

For the committed effective dose 

equivalent (see Table 5-1): 

(2 E-6 X 3.2E+4)+(4E-8 X 6.3 E+4) 

+(1.2E-5 x 5.3E+4) =0. 71 rem. 

For the committed dose equivalent to the thyroid (see Table 5-2): 

1.2E-5 x 1.3E+6 = 16 rem. 

The results of these. calculations 

show that, at the location for which 

these time-integrated concentrations 

are specified, the committed dose 

equivalent to the tll.yroid from 

inhalation would be over three times 

the PAG for dose to thyroid, thus 

justifying evacuation. Using 

meteorological dilution factors, one 

could calculate the additional distance 

to which evacuation would be justified 

for both effective dose and thyroid dose, 

where DRLi is the. derived response 

level for radionuclide i, and ci is 

defined above. If the sum in either 

case is equal to or greater than unity, 

evacuation of the general population is 

warranted. 

For effective dose (see 

Table 5-l): 

2E-6 + 4E-8 + 1.2E-5 = 0.7 

3.2E-5 1.6E-5 1.9E-5 

For dose to the thyroid (see 


Table 5-2): 


1.2E-5 = 3 

3.9E-6 

It is apparent that these calculations 

yield the same conclusions as those 

using the DCFs. 

5.4.3 Comparison with Previo~slyRecommended PAGs 

~any emergency response plans 

have already been developed using 

previously-recommended PAGs that 

apply to the dose equivalent to the 

whole body from direct (gamma) 

radiation from the plume and to the 

thyroid from inhalation of radioiodines. 

For nuclear power plant incidents, the 

5-16 

fanner P AG for whole body exposure 

provides public health protection 

comparable to that provided by the new 

P AG expressed in tenns of effective 

dose equivalent. This is demonstrated 

in Table C-9 (Appendix C), which 

shows comparative doses for nuclear 

power plant fuel-melt accident 

sequences having a wide range of 

magnitudes. The PAG for the thyroid 

is unchanged. On the other hand, 

application of these P AGs to alpha 

emitting radionuclides leads to quite 

different derived response levels from 

those based on earlier health physics 

considerations, because of new dose 

conversion factors and the weighting 

factors assigned to the exposed organs 

(EP-88). 

5.5 Protective Actions 

This section provides guidance for 

implementing the principal protective 

actions (evacuation and sheltering) for 

protection against the various exposure 

pathways resulting from an airborne 

plume. Sheltering means the use of 

the closest available structure which 

will provide protection from exposure 

to an airborne plume, and evacuation 

means the movement of individuals 

away from the path·ofthe plume. 

Evacuation and sheltering 

provide different levels of dose 

reduction for the principal exposure 

pathways (inhalation of radioactive 

material, and direct gamma exposure 

from the plume or from material 

deposited ·on surfaces). The 

effectiveness of evacuation will depend 

on many factors, s11ch as how rapidly it 

can be implemented and the nature of 

the accident. For accidents where the 

principal source of dose is inhalation, 

evacuation could increase exposure ifit 

is implemented during the passage ofa 

short-tenn plume, since moving 

vehicles provide little protection 

against exposure (D0-90). However, 

studies (NR-89a) continue to show that, 

for virtually all severe reactor accident 

scenarios, evacuation during plume 

passage does not increase the risk of 

acute health effects above the risk 

while sheltering. · Sheltering, which in 

most cases can.be almost immediately 

implemented, ·varies in usefulness 

depending upon the type of release, the 

shelter available, the duration of the 

plume passage, and climatic conditions. 

Studies have been conducted to 

evaluate shelter (EP-78a) and 

evacuation (HA-7 5) as protective 

actions for incidents at nuclear power 

facilities. Reference EP-78b suggests 

one method for evaluating and 

comparing the benefits of these· two 

actions. This requires collecting 

planning infonnation before and data 

following an incident, and using 

calculations and graphical means to 

evaluate whether evacuation, 

sheltering, or a combination . of 

sheltering followed by evacuation 

should be recommended at different 

locations. Because of the ·many· 

interacting variables, the user is forced' 

to choose between making decisions 

during the planning phase, based· on 

assumed data that may be grossly 

inaccurate, or using a time-consuming 

more comprehensive process after the 

5-17 

incident when data may be available. 

In the former situation, ·the decision 

may not have a sound basis, whereas 

in the latter, the decision may come too 

late to be useful. 

The recommended approach is to 

use planning information for making 

early decisions. The planned response 

should then be modified following the 

incident only if tim~ly detailed 

informationis available to support such 

modifications. 

The planner should :first compile 

the necessary information about the 

emergency planning zone (EPZ) around 

the facility. For the case of power 

reactors, some of this information is 

described in NUREG-0654 (NR-80). It 

should include identifying the 

population distribution, the sheltering 

effectiveness of residences and other 

structures, institutions containing 

population groups that require special 

consideration, evacuation routes, logical 

boundaries for evacuation zones, 

transportation systems, 

communications systems, and special 

problem areas. In addition, the 

plannershould identify the information 

that may be available following an 

incident, such as environmental 

monitoring data, meteorological 

conditions, and plant conditions. The 

planner should identify key data or 

information that would justify specific 

protective actions. The evaluation and 

planning should also , include the 

selection ofinstitutions where persons 

should be provided with ,stable iodine 

for thyroid protection· in situations 

where radioiodine inhalation is 

projected. 

The following sections discuss key 

factors which affect the choice between 

evacuation and sheltering. 

5.5.1 Evacuation 

The primary objective ofevacuation 

is to avoid exposure to airborne or 

deposited radioactive material by 

moving individuals away from the path 

ofthe plume. Evacuation, if completed 

before plume arrival, can be .100 

percent effective in avoiding future 

exposure. Even if evacuation coincides 

with or follows plume passage, a large 

reduction of exposure may be possible. 

In any case, the maximum dose 

avoided by evacuation will be the dose 

not avoidable by sheltering. 

Some general conclusions 

regarding evacuation (HA-75) which 

may be useful for planning purposes 

are summarized below: 

1. Advanced planning is essential to ~ 

identify potential problems that may 

occur in an evacuation. 

2. Most evacuees use their own 

personal transportation. 

3. Most evacuees assume the 

responsibility of acquiring food and 

shelter for themselves. 

4. Evacuation costs are highly 

location-dependent and usually will not 

5-18 

be a deterrent to carrying out an 

evacuation. 

5. Neither panic nor hysteria has 

been observed when evacuation oflarge 

areas is managed by public officials. 

6. Large or small population groups 

can be evacuated effectively with 

minimal risk ofinjury or death. 

7. The risk of injury or death to 

individual evacuees from transportation does not change as a function of 

the number of persons evacuated, and 

can be conservatively estimated using 

National Highway Safety Council 

statistics for motor vehicle accidents 

(subjective information suggests· that 

the risks will be lower). 

Evacuation of the elderly, the 

handicapped, and inhabitants of 

medical and other institutions may 

present special problems. When 

sheltering can provide adequate 

protection, this will often be the 

protective action of choice. However, if 

the general public is evacuated and 

those in institutions are sheltered, 

there is a risk that attendants at these 

institutions may leave and make later 

evacuation ofinstitutionalized persons 

difficult because of a lack of 

attendants. Conversely, if evacuation 

of institutions is attempted during 

evacuation ·of the public, traffic 

conditions may cause unacceptable 

delays. If evacuation ofinstitutions is 

attempted before evacuating the public, 

increased risk to the public from a 

delayed evacuation could occur, unless 

the incident is very slow in developing 

to the point of an atmospheric release. 

Because of the above difficulties, 

medical and other institutions located 

within the EPZ should be evaluated to 

determine whether there are any 

logical categories of persons that 

should be evacuated after the public 

(or; when time permits, before). 

5.5.2 Sheltering 

Sheltering refers here to the use of 

readily available nearby structures for 

protection against exposure to an 

airborne plume. 

Sheltering may be an appropriate 

protective action because: 

1. It positions the public to receive 

additional instructions when the 

possibility of high enough doses to 

justify evacuation exists, but is small. 

2. It may provide protection equal to 

or greater than evacuation. 

3. It is less expensive and disruptive 

than evacuation. 

4. Since it may ·be implemented 

rapidly, sheltering may be the 

protective action of choice if ·rapid 

evacuation is impeded by, a) severe 

environmental conditions--e.g. severe 

weather or floods; b) health 

constraints--e.g. patients and workers 

in hospitals and nursing homes; or c) 

long mobilization times--certain 

industrial and farm workers, or 

prisoners and guards; d) physical 

5-19 

constraints to evacuation--e.g. 

inadequate roads. 

5. Sheltering may be more effective 

against inhalation of radioactive 

particulates than against external 

gamma exposure, especially for shortterm plumes. 

The use oflarge structures, such as 

shopping centers, schools, churches, 

and commercial buildings, as collection 

points during evacuation· mobilization 

will generally provide greater 

protection against gamma radiation 

than use ofsmall structures. 

As with evacuation, delay in taking 

shelter during plume passage will 

reduce the protection from exposure to 

radiation. The degree of protection 

provided by structures is. governed by 

attenuation of gamma :radiation by 

structural components (the mass of 

walls, ceilings, etc.) and by 

outside/inside air-exchange rates. 

If external dose from the plume or 

from deposited materials is the 

controlling criterion, shelter 

construction and shelter size are the 

most important considerations; 

ventilation control and filtering are less 

important. Although sheltering will 

reduce the gamma exposure rate from 

deposited materials, it is not a suitable 

protective action for this 'pathway for 

long duration exposure. The main 

factors which reduce whole body 

exposure are: 

1. Wall materials and thickness and 

size ofstructure, 

2. Number of stories overhead, and 

3. Use of a central location within. 

the structure. 

If a major release of radioiodine or 

respirable particulate materials occurs, 

inhalation dose will be the controlling 

pathway. For releases consisting 

primarily of noble gases, external 

gamma exposure will be most 

important. However, when inhalation 

is the primary exposure pathway, 

consideration should be given to the 

following: 

1. Ventilation control is essential for 

effective sheltering. 

2. Dose reduction factors for 

sheltering can be improved in several 

ways for the inhalation pathway, 

including reducing air exchange rates 

by sealing cracks and openings with 

cloth or weather stripping, tape, etc. 

Although the risk to health from the 

action could be a constraint 

(particularly for infants and the 

infirm), using wet towels or 

handkerchiefs as a mask to filter the 

inhaled air will reduce dose from 

inhalation. 

3. Following plume passage, people 

should open shelters to reduce airborne 

activity trapped inside, and they should 

leave high exposure areas as soon as 

possible after cloud passage to avoid 

exposure to deposited radioactive 

material 

4. Consideration should be given to 

the prophylactic administration of 

potassium iodide (KI) as a 

5-20 

thyroid-blocking agent to workers 

performing emergency services and 

other groups in accordance with the 

P AGs in Table 2-1 and the provisions 

in reference FD-82.3 

5.5.3 General Guidance for Evacuation 

and Sheltering 

The process of evaluating, 

recommending, and implementing 

evacuation or shelter for the public is 

far from an exact science, particularly 

in view oftime constraints that prevent 

thorough analysis ~t the time of an 

incident. Their effectiveness, however, 

can be improved considerably by 

planning and testing. Early decisions 

should be based on information 

collected from the emergency planning 

zone during the planning phase and on 

information regarding conditions at the 

nuclear facility at the time of the 

incident. Best estimates of dose 

projections should be used for decisions 

between evacuation and sheltering. 

The following is a summary of 

planning guidance for evacuation and 

sheltering, based on the information in 

.Sections 5.5.1 and 5.5.2. 

1. For severe incidents, where PAGs 

may be significantly exceeded, 

3

Each State has the responsibility for 

formulating guidance to define when {and if) 

the public should be given potassium iodide. 

Planning for its use is discussed in "Potassium 

Iodide as a Thyroid-blocking Agent in a 

Radiation Emergency: Final Recommendations 

on Use" {FD-82). 

evacuation may be the only effective 

protective action close to the facility. 

2. Evacuation will provide total 

protection from any airborne release if 

it is. completed before arrival of the 

plume. 

3. Evacuation may increase exposure 

if carried out during the plume 

passage, for accidents involving 

inhalation dose as a major contributor. 

4. Evacuation is also appropriate for 

prot~ction from groundshine in areas 

with high exposure rates from 

deposited materials. I 

I 

5. ' Sheltering may be appropriate 

(when available) for areas not 

designated for immediate evacuation 

because: 

a. It positions the public to receive 

additional instructions; and 

b. It may provide protection equal to 

or greater than evacuation. 

6. Sheltering is usually not 

appropriate where high doses are 

projected or for exposure lasting longer 

than two complete air exchanges ofthe 

shelter. 

7. Because sheltering may be 

implemented in less time than 

evacuation, it may be the temporary 

protective action of choice if rapid 

evacuation is impeded by a) certain 

environmental conditions--e.g. severe 

weather or floods; b) health 

constraints--e.g. patients and workers 

5-21 

in hospitals and nursing homes; or c) 

long mobilization times--e.g. certain 

industrial and farm workers, or 

prisoners and guards; d) physical 

constraints to evacuation--e.g. 

inadequate roads. 

8. If a major release of radioiodine or 

particulate materials occurs, inhalation 

dose may be the controlling criterion 

for protective actions. In this case: 

a. Breathing air filtered through 

common household items (e.g., 

folded wet handkerchiefs or towels) 

may be of significant help, if 

appropriate precautions are taken 

to avoid possible suffocation. 

b. After confirmation that the 

plume has passed, shelters should 

be opened to avoid airborne activity 

trapped inside, and persons should 

leave high exposure areas as soon 

as possible after cloud passage to 

avoid exposure to deposited 

radioactive material. 

c. Consideration should be given to 

the prophylactic administration of 

potassium iodide (KI) as a 

thyroid-blocking agent to emergency 

workers, workers in critical 

industries, or others in accordance 

with the PAGs in Table 2-1 and 

reference FD-82. 

9. If dose from external gamma 

radiation is the controlling criterion, 

shelter construction and size are the 

most important considerations; 

ventilation control and filtering are less 

important. The main factors which 

reduce whole body external dose are; a) 

wall thickness and size ofstructure, b) 

number of stories overhead, c) central 

location within the structure, and d) 

the height of the cloud with respect to 

the building. 

5.6 Procedures for Calculating Dose 

Conversion Factors 

This section provides information 

used in the development ofthe DCFs in 

Tables 5-l and 5-2. Three exposure 

pathways are included: whole body 

exposure to gamma radiation from the 

plume, inhalation from the plume, and 

whole body exposure to gamma 

radiation from deposited materials. 

Although exposure of the skin from 

beta radiation could be significant, 

evaluations show that other exposure 

pathways will be controlling for 

evacuation and sheltering decisions. 

Therefore, DCFs for skin are not 

provided. Individual DCFs for the 

three exposure pathways are provided 

in the following sections. They are 

each expressed in terms of the timeintegrated air concentration so that 

they may be combined to yield a 

composite DCF for each radionuclide 

that reflects all three pathways. These 

data may be used. to facilitate revising 

the DCFs in TaMes 5-l and 5-2 when 

more specific or technically improved 

assumptions are available, as well as to 

evaluate the relative importance ofthe 

individual pathways for specific 

radionuclide mixes. 

5-22 

5.6.1 Extemal Exposure to Gamma 

Radiation from the Plume 

Table 5-3 provides DCFs and DRLs 

for extemal exposure to gamma 

radiation due to immersion in 

contaminated air. The values for 

gamma radiation will provide 

conservative estimates for exposure to 

an overhead plume. They are derived 

under the assumption that the plume 

is correctly approximated by a semiinfinite source. 

The DCFs given in Table 5-3 are used 

to calculate the effective dose 

equivalent from external exposure to 

gamma radiation from the plume. 

They are based on dose-rate conversion 

factors for effective dose in Table A.1 of 

reference D0-88. The units given in 

Table A.1 are converted to those in 

Table 5-3 as follows: 

-1 

mrem · y x 0.

1142 = rem 

p.Ci · m -

3 p.Ci • em -

3 • h 

Only the short-lived daughters of Ru106 and Cs-137 emit gamma radiation 

and, therefore, the DCFs from Table 

A.1 for these entries are attributable to 

their daughters. The DCF for Ce-144 

is combined with that for its short-lived 

daughter; it is assumed they are in 

equilibrium. Since the DRLs apply to 

a PAG of 1 rem, they are simply the 

reciprocals of the DCFs. 

5.6.2 Inhalation from the Plume 

Table 5-4 provides DCFs and DRLs 

for committed effective dose equivalent 

due to inhalation of an airbome plume 

ofradioactive particulate materials and 

for committed dose equivalent to the 

thyroid due to inhalation · of 

radioiodines. It is assumed that the 

radionuclides are in the chemical and 

physical form that yields the highest 

dose, and that the particle s!ze is one 

micrometer lllean aerodynamic 

diameter. For . other chemical an4 

physical forms "o( practical interes~ the 

doses may differ, but :j.n general only by 

a small factor. If the chemical and/or 

physical form (e.g. solubility class or 

particle size) is .known or can be 

predicted, .the :OCFs for inhalation 

should be adj':lsted as appropric;tte. 

The dosefactors and breathing rate 

used to develop the DCFs in Table 5-4 

are those given in. Table 2.1 of Federal 

Guidance Report No.11 and were 

derived for "standard man" (EP-88). 

Although the . DCFs ':for· .some 

radionuclides would be slightly higher 

for children,' the conservatism in the 

P AGs . and procedures for ·their 

application provide an adequate margin 

for safety. The advantage of using a 

single source . of current data for the 

development and .timely revisio1.1 of 

DCFs for these and any other relevant 

radionuclides 1s also aconsideration in 

the selection of this data base for use 

in emergency respopse. applications. 

The units given in Table 2-1 ofEP-88 

are converted to the units in Table 5-4, 

using a breathing rate of 1.2E+6 cm3 • 

h-I, by the factor · · 

Sv·Bq-1 • 4.4E+12 =.rem per . p.Ci· cm-3 • h.··· 

5-23 

The DRLs are simply the reciprocal of 

the DCF. 

5.6.3 External Dose from Deposited 

Materials 

Table 5-5 provides DCFs and DRLs 

for 4-day exposw.·e to gamma radiation 

from selected radionuclides following 

deposition of particulate materials on 

the ground from a plume. The 

deposition velocity (assuri::ted to be 1 

cm/s for iodines and 0.1 cm/s for other 

particulate materials) could vary 

widely depending on the physical and 

chemical characteristics of the 

deposited material and the surface, and 

meteorological conditions. In the case 

of precipitation, the ·amount of 

deposition (and thus the dose 

conversion factors for this exposure 

pathway) will be much higher. To 

account for the ingrowth of short-lived 

daughters in deposited materials after 

measurements are made, the tabulated 

values include their contribution to 

dose over the assumed 4-day period of 

exposure. Because the deposition 

velocity can be much lower or higher 

than assumed in developing the dose 

conversion factors for deposited 

materials, decision makers are 

cautioned to pay particular attention to 

actual measurements ·of gamma 

exposure from deposited materials for 

evacuation decisions after plume 

passage. 

The objective is to calculate DCFs for 

single radionuclides in terms of 

effective dose equivalent from 4 days 

exposure to gamma radiation from 

deposited radioactive materials. In 

order to be able to sum the dose 

conversion factors with those for other 

exposure pathways, the DCF is 

expressed in terms of dose per unit 

time-integrated air concentration, 

where the deposition from the plume is 

assumed to occur at approximately the 

beginning of the incident. The 

following equation was used to 

generate Table 5-5: 

DCF = Vc· DCRF • 1.14E-3[ ­ ] A 

Where: 

DCF = the dose per unit air 

concentration (J.lCi• cm·3

• h) 

Vg = the deposition velocity, . 

assumed to be 3600 em· h"1 

for iodines and 360 em· h"1 

for other particulate 

materials 

DRCF = the dose rate conversion 

factor (mrem· y·1 per 

pCi· m"2

) (D0-88) 

1.14E-3 =a factor converting 

mrem· y"1 per m2 to 

rem· h"1 per cm2 

A = the decay constant for the 

radionuclide (h"1

) 

t = duration of exposure 

(hours),assumed to be 96 

hours ( 4 days) 

1 e-?.t 
Table 5-3 Dose Conversion Factors (DCF) and Derived Response Levels (DRL) for 

External Exposure Due to Immersion in Contaminated Air 

Radionuclide 

H-3 

C-14 

Na-22 

Na-24 

P-32 

P-33 

S-35 

Cl-36 

K-40 

K-42 

Ca-45 

Sc-46 

Ti-44 

V-48 

Cr-51 

Mn-54 

Mn-56 

Fe-55 

Fe-59 

Co-58 

Co-60 

Ni-63 

Cu-64 

Zn-65 

Ge-68 

Se-75 

Kr-85 

Kr-85m 

Kr-87 

Kr-88 

DCFa 


rem per 


p.Ci · cm·3 • h 


O.OE+OO 

O.OE+OO 

1.3E+03 

2.7E+03 

O.OE+OO 

O.OE+OO 

O.OE+OO 

4.8E-06 

9.2E+01 

1.7E+02 

9.3E-09 

1.2E+03 

7.7E+01 

1.7E+03 

1.8E+01 

5.0E+02 

1.1E+03 

1.3E-02 

7.0E+02 

5.8E+02 

1.5E+03 

O.OE+OO 

1.1E+02 

3.4E+02 

5.2E-02 

2.3E+02 

1.3E+00 

9.3E+01 

5.1E+02 

1.3E+03 

O.OE+OO 

O.OE+OO 

7.8E-04 

3.7E-04 

O.OE+OO 

O.OE+OO 

O.OE+OO 

2.1E+05 

l.lE-02 

6.0E-03 

1.1E+08 

8.4E-04 

.1.3E-02 

5.8E-04 

5.6E-02 

2.0E-03 

9.4E-04 

7.6E+01 

'1.4E-03 

1.7E-os· 

6.7E-04 

O.OE+OO 

9.2E-03 

2.9E-03 

1.9E+01 

4.4E-03 

7.8E-Ol 

1.1E~02 

2.0E-03 

7.8E-04 

5-25 

Table 5-3, Continued > • " ' ' ' ~ 

DC? DRLb 

Radionuclide rem per 

pCi • cm·3 • h 

pCi · cm·3 • h 

Kr-89 1.2E+03 8.6E-04. 

Rb-86 5.6E+01 1.8E-02 

Rb-88 4.1E+02 2.5E-03. 

Rb-89 1.3E+03 7.7E-04 

Sr-89 8.2E-02 1.2E.+01 

Sr-90 O.OE+OO O.OE+OO 

Sr-91 4.1E+02 2.4E-03 

Y-90 O.OE+OO O.OE+OO 

Y-91 2.1E+00 4.7E-01 

Zr-93 O.OE+OO O.OE+OO 

Zr-95 4.3E+02 2.3E-03 

Zr-97 1.1E+02 9.3E-03 

Nb-94 9.3E+02 1.1E-03 

Nb-95 4.5E+02 2.2E-03 

Mo-99 9.1E+01 1.1E-02 

Tc-99 3.0E-04 3.3E+03 

Tc-99m 7.6E+01 1.3E-02 

Ru-103 2.8E+02 3.6E-03 

Ru-105 4.6E+02 2.2E-03 

Ru/Rh-10SC 1.2E+02 8.4E-03 

Pd-109 3.9E-01 2.5E+00 

Ag-110m 1.6E+03 6.2E-04 

Cd-109 1.3E+00 8.0E-01 

Cd-113m O.OE+OO O.OE+OO 

In-114m 5.2E+01 1.9E-02 

Sn-113 4.8E+00 2.1E-01 

Sn-123 4.1E+00 2.4.E-01 

Sn-125 1.8E+02 5.4E-03 

Sn-126 2.8E+01 3.6E-02 

Sb-124 1.1E+03 8.8E-04 

5-26 
Table 5-3, Continued 

DC? DRLb 

Radionuclide remper · J1Ci · cm·3 • h 

J1Ci · cm·3 • h 

Sb-126 1.6E+03 6.2E-04 

Sb-127 3.9E+02 2.6E-03 

Sb-129 8.6E+02 1.2E-03 

Te-127m 1.8E+00 5.6E-01 

Te-129 3.1E+01 3.2E-02 

Te-129m 2.0E+01 5.1E:-02 

Te-131m 8.5E+02 1.2E-03 

Te-132 1.2E+02 8.0E-03 

Te-134 5.1E+02 2.0E-03 

I-125 6.3E+00 1.6E-01 

I-129 4.8E+00 2.1E-01 

I-131 2.2E+02 4.6E-03 

I-132 1.4E+03 7.4E-04 

I-133 3.5E+02 2.9E-03 

I-134 1.6E+03 6.4E-04 

I-135 9.5E+02 1.1E-03 

Xe-131m 4.9E+00 2.0E-01 

Xe-133 2.0E+01 · 5.0E-02 

Xe-133m 1.7E+01 5.9E-02 

Xe-135 1.4E+02 7.0E-03 

Xe-135m 2.5E+02 4.1E-03 

Xe-137 1.1E+02 9.2E-03 

Xe-138 7.1E+02 1.4E-03 

Cs-134 9.1E+02 1.1E-03 

Cs-136 1.3E+03 7.8E-04 

Cs/Ba-137° 3.5E+02 2.9E-03 

Cs--138 1.4E+03 6.9E-04 

Ba-133 2.1E+02 4.8E-03 

Ba-139 2.1E+01 4.9E-02 

Ba-140 1.1E+02 9.3E-03 

5-27 
Table 5-3, Continued 

DCFa DRLb 

Radionuclide rem per 

pCi · cm·3 • h 

pCi · cm·3 • h 

La-140 1.4E+03 7.1E-04 

La-141 2.5E+01 3.9E-02 

La-142 1.8E+03 5.6E-04 

Ce-141 4.4E+01 2.3E-02 

Ce-143 1.5E+02 6.6E-03 

Ce-144 1.0E+Ol 9.7E-02 

Ce/Pr-144c 3.1E+01 3.2E-02 

Nd-147 7.6E+01 1.3E-02 

Pm-145 9.5E+00 1.0E-01 

Pm-147 2.1E-03 4.8E+02 

Pm-149 6.7E+00 1.5E-01 

Pm-151 1.9E+02 5.2E-03 

Sm-151 5.2E-04 1.9E+03 

Eu-152 6.7E+02 1.5E-03 

Eu-154 7.4E+02 1.3E-03 

Eu-155 3.3E+01 3.1E-02 

Gd-153 5.1E+01 2.0E-02 

Tb-160 6.4E+02 1.6E-03 

Ho-166m 9.4E+02 1.1E-03 

Tm-170 2.7E+00 3.8E-01 

Yb-169 1.6E+02 6.1E-03 

Hf-181 3.1E+02 3.2E-03 

Ta-182 7.6E+02 1.3E-03 

W-187 2.7E+02 3.6E-03 

Ir-192 4.7E+02 2.1E-03 

Au-198 2.3E+02 4.3E-03 

Hg-203 1.3E+02 7.6E-03 

Tl-204 5.8E-01 1.7E+00 

Pb-210 7.6E-01 1.3E+00 

Bi-207 9.1E+02 1.1E-03 

5-28 

Table 5-3, Continued 

DCFa DRLb 

Radionuclide rem per 

pCi · cm·3 • h 

pCi · cm·3 • h 

Bi-210 · O.OE+OO O.OE+OO 

Po-210 5.1E-03 2.0E+02 

Ra-226 3.9E+00 2.6E-01 

Ac-227 7.2E-02 1.4E+01 

Ac-228 5.5E+02 1.8E-03 

Th-227 6.0E+01 1.7E-02 

Th-228 1.1E+00 8.9E-01 

Th-230 2.2E-01 4.5E+00 

Th-232 1.1E-01 9.4E+00 

Pa-231 1.7E+01 5.8E-02 

U-232 1.5E-01 6.6E+00 

U-233 1.4E-01 7.3E+00 

U-234 8.7E-02 1.1E+01 

U-235 8.8E+01 1.1E-02 

U-236 6.9E-02 1.4E+01 

U-238 5.9E-02 1.7E+01 

U-240 4.1E-01 2.4E+00 

Np-237 1.3E+01 7.6E-02 

Np-239 9.6E+01 1.0E-02 

Pu-236 6.8E-02 1.5E+01 

Pu-238 5.0E-02 2.0E+01 

Pu-239 4.7E-02 2.1E+01 

Pu-240 4.9E-02 2.0E+01 

Pu-241 O.OE+OO O.OE+OO 

Pu-242 4.2E-02 2.4E+01 

Am-241 1.1E+01 9.2E-02 

Am-242m 2.7E-01 3.7E+00 

Am-243 2.9E+01 3.4E-02 

Cm-242 5.6E-02 1.8E+01 

Cm-243 7.3E+01 1.4E-02 

5-29 
Table 5-3, Continued 

DC~ DRLb 

Radionuclide rem per _ pCi · cm·8 •. h · 

pCi · em-a •h 

Cm-244 4.8E-02 2.1E+01 

Cm-245 4.1E+Ol 2.5E-02 · 

Cm-246 4.0E-02 2.5E+Ol 

Cf-252 4.3E-02 2.3E+Ol 

•ncFs are expressed in terms of committed effective dose equivalent and are based on data from 

reference (D0-88). 

bAssumes a PAG of one rem committed effective dose equivalent. 

<The contribution from the short-lived daughter is included in the factors for the parent 

radionuclide. 

'5-30 

Table 5-4 Dose Conversion Factors (DCF) and Derived Response Levels (DRL) for 

Doses.Due to Inhalationa 

Lung 

Radionuclide Class 

H-3 ye 

C-14 L ORG Cd 

Na-22 D 

Na-24 D 

P-32 w 

P-33 w 


S-35 w 


Cl-36 w 


K-40 D 


K-42 D 


Ca-45 w 

Sc-46 y

Ti-44 
 y

V-48 w 


Cr-51 y

Mn-54 w 


Mn-56 D 


Fe-55 D 


Fe-59 D 


Co-58 y

Co-60 
 y

Ni-63 Vapor 


Cu-64 y

Zn-65 
 y

Ge-68 w 


Se-75 w 


Rb-86 D 


Rb-88 D 


Rb-89 D 


Sr-89 y

DCF 


·rem per 


pCi -·.·cm·3 • h 


7.7E+01 

2.5E+03 

9.2E+03 

1.5E+03 

1.9E+04 

2.8E+03 


3.0E+03 


2.6E+04 


· 1.5E+04 


1.6E+03 


7.9E+03 

3.6E+04 

1.2E+06 

1.2E+04 

4.0E+02 

8.0E+03 

4.5E+02 

3.2E+03 

1.8E+04 

1.3E+04 

2.6E+05 

7.5E+03 

3.3E+02 

2.4E+04 

6.2E+04 

1.0E+04 

7.9E+03 

1.0E+02 

5.2E+01 

5.0E+04 

'5-31 

DRLb 


pCi . · cm·8 • h 


1.3E-02 ·· 

4.0E-04 

1.1E-04 

6.9E-04 

5.4E-05 

3.6E-04 

3.4E-04 

3.8E-05 

6.7E-05 · 

6.1E-04 

1.3E-04 

2.8E-05 

8.2E-07 

8.2E-05 

2.5E-03 

1.2E-04 

2.2E-03 

3.1E-04 

5.6E-05 

7.7E-05 

3.8E-06· 

1.3E-04 

3.0E-03 

4.1E-05 

1.6E-05 

9.8E-05 

1.3E-04 

l.OE-02 

1.9E-02 

2.0E-05 
Radionuclide 

Sr-90 

Sr-91 

Y-90 

Y-91 

Zr-93 

Zr-95 

Zr-97 

Nb-94 

Nb-95 

Mo-99 

Tc-99 

Tc-99m 

Ru-103 

Ru-105 

Ru/Rh-106° 

Pd-109 

Ag-110m 

Cd-109 

Cd-113m 

In-114m 

Sn-113 

Sn-123 

Sn-125 

Sn-126 

Sb-124 

Sb-126 

Sb-127 

Sb-129 

Te-127m 

Te-129 

Lung 


Class 


y 

y 

y 

y 

D 

D 

y 

y 

y 

y 

w 

D 

y 

y 

y 

y 

y 

D 

D 

D 

w 

w 

w 

w 

w 

w 

w 

w 

w 

D 

Table 5-4, Continued. 

DCF 


rem per 


pCi · cni3 • h 


1.6E+06 

2.0E+03 

1.0E+04 

5.9E+04 

3.8E+05 

2.8E+04 

5.2E+03 

5.0E+05 

7.0E+03 

4.8E+03 

1.0E+04 

3.9E+01 

1.1E+04 

5.5E+02 

5.7E+05 

1.3E+03 

9.6E+04 

1.4E+05 

1.8E+06 

1.1E+05 

1.3E+04 

3.9E+04 

1.9E+04 

1.2E+05 

3.0E+04 

1.4E+04 

7.2E+03 

7.7E+02 

2.6E+04 

1.1E+02 

5-32" 

DRLb 


pCi · cm·3 • h 


6.4E-07 

5.0E-04 

9.9E-05 

1.7E-05 

2.6E-06 

3.5E-05 

1.9E-04 

2.0E-06 

1.4E-04 

2.1E-04 

1.0E-04 

2.6E-02 

9.3E-05 

1.8E-03 

1.7E-06 

7.6E-04 

1.0E-05 

7.3E-06 

5.5E-07 

9.4E-06 

7.8E-05 

2.6E-05 

5.4E-05 

8.4E-06 

3.3E-05 

7.1E-05 

1.4E-04 

1.3E-03 

3.9E-05 

9.3E-03 
Radionuclide 

Te-129m 

Te-131m 

Te-132 

Te/I-132e 

Te-134 

I-125 

I-129 

I-131 

I-132 

I-133 

I-134 

I-135 

Cs-134 

Cs-136 

Cs/Ba-137e 

Cs-138 

Ba-133 

Ba-139 

Ba-140 

La-140 

La-141 

La-142 

Ce-141 

Ce-143 

Ce-144 

Ce/Pr-144e 

Nd.:147 

Pm-145 

Pm-147 

Pm-149 

Lung 


Class 


w 

w 

w 

w 

D 

D 

D 

D 

D 

D 

D 

D 

D 

D 

D 

D 

D 

D 

D 

w 

D 

D 

y 

y 

y 

y 

y 

y 

y 

y 

Table 5-4, Continued. 

DCF DRLb 

rem per pCi · cm·3 • h 

p.Ci • cm'3 • h 

2.9E+04 3.5E-05 

7.7E+03 1.3E-04 

1.1E+04 8.8E-05 · 

1.2E+04 8.5E-05 

1.5E+02 6.5E-03 

2.9E+04 3.4E-05 

2.1E+05 4.8E-06 

3.9E+04 2.5E-05 

4.6E+02 2.2E-03 

7.0E+03 1.4E-04 

1.6E+02 6.3E-03 

1.5E+03 6.8E-04 

5.6E+04 1.8E-05 

8.8E+03 1.1E-04 

3.8E+04 2.6E-05 

1.2E+02 8.2E-03 

9.4E+03 1.1E-04 

2.1E+02 4.9E-03 

4.5E+03 2.2E-04 

5.8E+03 1.7E-04. 

7.0E+02 1.4E-03 

3.0E+02 3.3E-03 

1.1E+04 9.3E-05 

4.1E+03 2~5E-04 

4.5E+05 2.2E-06 

4.5E+05 2.2E-06 

8.2E+03 1.2E-04 

3.7E+04 2.7E-05 

4.7E+04 2.1E-05 

3.5E+03 2.8E-04 

5-33 
Radionuclide 

Pm-151 

Sm-151 

Eu-152 

Eu-154 

Eu-155 

Gd-153 

Tb-160 

Ho-166m 

Tm-170 

Yb-169 

Hf-181 

Ta-182 

W-187 

Ir-192 

Au-198 

Hg-203 

Tl-204 · 

Pb-210 

Bi-207 

Bi-210 

Po-210 

Ra-226 

Ac-227 

Ac-228 

Th-227 

Th-228 

Th-230 

Th-232 

Pa-231 

U-232 

Lung 


Class 


y 

w 

w 

w 

w 

D 

w 

w 

w 

y 

D 

y 

D 

y 

y 

D 

D 

D 

w 

D 

D 

w 

D 

D 

y 

y 

w 

w 

w 

y 

Table 5-4, Continued. 

DCF 


rem per 


p.Ci · cm·8 • h 


2.1E+03 

3.6E+04 

2.7E+05 

3.4E+05 

5.0E+04 

2.9E+04 

3.0E+04 

9.3E+05 

3.2E+04 

9.7E+03 

1.9E+04 

5.4E+04 

7.4E+02 

3.4E+04 

3.9E+03 

8.8E+03 

2.9E+03 

1.6E+07 

2.4E+04 

1.9E+04 

1.1E+07 

1.0E+07 

8.0E+09 

3.7E+05 

1.9E+07 

4.1E+08 

3.9E+08 

2.0E+09 

1.5E+09 

7.9E+08 

5-34 

DRLb 


p.1·cm c· -s h
 · 

4.8E-04 

2.8E-05 

3.8E-06 

2.9E-06 

2.0E-05 

3.5E-05 

3.3E-05 

1.1E-06 

3.2E-05 

1.0E-04 

5.4E-05 

1.9E-05 

1.3E-03 

3.0E-05 

2.5E-04 

1.1E-04 

3.5E-04 

6.1E-08 

4.2E-05 

5.4E-05 

8.9E-08 

9.7E-08 

1.2E-10 

2.7E-06 

5.2E-08 

2.4E-09 

2.6E-09 

5.1E-10 

6.5E-10 

1.3E-09 
Radionuclide 

U-233 

U-234 

U-235 

U-236 

U-238 

U-240 

Np-237 

Np-239 

Pu-236 

Pu-238 

Pu-239 

Pu-240 

Pu-241 

Pu-242 

Am-241 

Am-242m 

Am-243 

Cm-242 

Cm-243 

Cm-244 

Cm-245 

Cm-246 

Cf-252 

Te/I-132e 

I-125 

I-129 

I-131 

Lung 


Class 


y 


y 


y 


y 


y 


y 

w 

w 

w 

w 

w 

w 

w 

w 

w 

w 

w 

w 

w 

w 

w 

w 

y 

WID 

D 

n· 

D 

Table 5-4, Continued. 

DCF 


rem per 


pCi · cm·3 • h 


1.6E+08 

1.6E+08 

1.5E+08 

1.5E+08 

1.4E+08 

2.7E+03 

6.5E+08 

3.0E+03 

1.7E+08 

4.7E+08 

5.2E+08 

5.2E+08 

9.9E+06 

4.9E+08 

5.3E+08 

5.1E+08 

5.3E+08 

2.1E+07 

3.7E+08 

3.0E+08 

5.5E+08 

5.4E+08 

1.9E+08 

Thyroid Dose 

2.9E+05 

9.6E+05 

6.9E+06 

1.3E+06 

DRLh 

P.ci · cm·3 • h 

6.2E-09 

6;3E-09 

6.8E-09 

6.6E-09 

7.0E~09 

3.7E-04 

1.5E-09 

3.3E-04 

5.8E-09 

2.1E-09 

1.9E-09 

1.9E-09 

1.0E-07 

2.0E-09 

1.9E-09 

2.0E-09 

1.9E-09 

4.8E-08 

2.7E-09 

3.4E-09 

l.SE-09 

1.8E-09 

5.3E-09 

1.8E-05 

5.2E-06 

7.2E-07 

3.9E-06 

5-35 

Table 5-4, Continued. 

Lung DCF 


Radionuclide Class rem per 


p.Ci · cm·3 • h 


I-132 D 7.7E+03 6.5E-04 

I-133 D 2.2E+05 2.3E-05 

I-134 D 1.3E+03 3.9E-03 

I-135 D 3.8E+04 l.SE-04 

arrhese factors and levels apply to adults (IC-75) and are based on Federal Guidance Report No. 11 

(EP-88). They are also based on the lung class that results in the most restrictive value. DCFs are 

expressed in terms of committed effective dose equivalent, except for those for thyroid dose, which 

are in terms of committed dose equivalent. 

bDRLs are based on a dose of 1 rem committed effective dose equivalent, except those for thyroid 

dose radionuclides, which are based on a committed dose equivalent of 5 rem. 

r:v denotes water vapor. 

dL ORG C denotes labelled organic compounds. 

°Contributions from short-lived daughters are included in the factors for parent radionuclides. 

5-36 

~ 

Table 5-5 Dose Conversion Factors (DCF) and Derived Response Levels (DRL) 

for a 4-Day Exposure to Gamma Radiation from Deposited 

Radionuclidesa 

Radionuclide 

H-3 


C-14 


Na-22 


Na-24 


P-32 


P-33 


S-35 


Cl-36 


K-40 


K-42 


Ca-45 


Sc-46 


Ti-44 


V-48 


Cr-51 


Mn-54 


Mn-56 


Fe-55 


Fe-59 


Co-58 


Co-60 


Ni-63 


Cu-64 


Zn-65 


Ge-68 


Se-75 


Rb-86 


Rb-88 


Rb-89 


Sr-89 


DCFb 


rem per 


J.ICi · cm..a •h 


O.OE+OO 

O.OE+OO 

8.3E+03 

3.1E+03 

O.OE+OO 

O.OE+OO 

O.OE+OO 

1.8E-04 

5.4E+02 

1.8E+02 

8.4E-07 

7.5E+03 

6.7E+02 

l.OE+04 

1.3E+02 

3.3E+03 

2.4E+02 

8.7E-01 

4.2E+03 

3.8E+03 

8.9E+03 

O.OE+OO 

1.5E+02 

2.1E+03 

4.5E+00 

1.7E+03 

3.3E+02 

l.OE+Ol 

2.9E+01 

5.2E-Ol 

DRLb,c 


c· -a h
 J.l 1 ·em · . 

O.OE+OO 

O.OE+OO 

1.2E-04 

3.2E-04 

O.OE+OO 

O.OE+OO 

· O.OE+OO 


5.4E+03 


1.9E-03 


5.7E-03 


1.2E+06 

1.3E-04 

1.5E-03 

l.OE-04 

7.8E-03 

3.0E-04 

4.1E-03 

l.lE+OO 

2.4E-04 

2.6E-04 

l.lE-04 

O.OE+OO 

6.8E-03 

4.7E-04 

2.2E-01 

5.9E-04 

3.0E-03 

9.8E-02 

3.4E-02 

1.9E+00 

5-37 

Table 5-5, Continued. 

DCFb DRLb,c 

Radionuclide rem per p.Ci · cm·a · h 

p.Ci · cm·8 • h 

Sr-90 O.OE+OO O.OE+OO 

Sr-91 3.8E+02 2.6E-03 

Y-90 O.OE+OO O.OE+OO 

Y-91 1.3E+01 7.8E-02 

Zr-93 O.OE+OO O.OE+OO 

Zr-95 2.9E+03 3.5E-04 

Zr-97 1.7E+02 5.8E-03 

Nb-94 6.3E+03 1.6E-04 

Nb-95 2.9E+03 3.4E-04 

Mo-99 4.0E+02 2.5E-03 

Tc-99 2.5E-03 4.0E+02 

Tc-99m 5.3E+01 1.9E-02 

Ru-103 1.9E+03 5.2E-04 

Ru-105 2.1E+02 4.7E-03 

Ru!Rh-106d 8.3E+02 1.2E-03 . 

Pd-109 5.6E-01 . 1.8E+00 

Ag-110m 1.2E+02 8.2E-:03 

Cd-109 3.7E+01 2.7E-02 

Cd-113m O.OE+OO O.OE+OO 

In-114m 3.8E+02 2.7E-03 

Sn-113 5.9E+01 1.7E-02 

Sn-123 2.6E+01 3.9E-02 

Sn-125 1.0E+03 1.0E-03 

Sn-126 2.4E+02 4.1E-03 

Sb-124 6.8E+03 1.5E-04 

Sb-126 9.9E+03 1.0E-04 

Sb-127 1.9E+03 5.2E-04. 

Sb-129 3.7E+02 2.7E-03 

Te-127m 2.6E+01 3.8E-02 

Te-129 3.9E+00 2.6E-01 

5-38 

Table 5-5, Continued. 

DCFb DRLb,c 

Radionuclide rem per J.ICi · cm·3 • h 

h J.li·cm c· -a · 

Te-129m 1.4E+02 7.2E-03 

Te-131m 3.5E+01 2.8E-02 

Te-132 6.6E+02 1.5E-03 

Te/I-132d 6.7E+03 1.5E-04 

Te-134 3.8E+01 2.7E-02 

I-125 9.5E+02 l.OE-03 

I-129 8.7E+02 1.2E-03 

I-131 1.3E+04 7.4E-05· 

1~132 3.1E+03 3.2E-04 

I-133 7.3E+03 1.4E-04. 

I-134 1.3E+03 7.5E-04 

I-135 5.7E+03 1.8E-04 

Cs-134 6.2E+03 1.6E-04 

Cs-136 7.6E+03 1.3E-04 

Cs/Ba-137d 2.4E+03 4.1E-04 

Cs-138 6.8E+01 1.5E-02 

Ba-133 1.7E+03 6.1E-,04 

Ba-139 3.2E+00 3.1E-01 

Ba-140 7.0E+02 1.4E-03 

La-140 4.1E+03 2.4E-04 

La-141 8.9E+00 1.1E-01 

La-142 2.3E+02 4.3E-03 

Ce-141 3.3E+02 3.0E-03 

Ce-143 4.8E+02 2.1E-03 

Ce-144 8.5E+01 1.2E-02 

Ce/Pr-144d 2.0E+02 5.0E-03 

Nd-147 5.2E+02 1.9E-03 

Pm-145 1.1E+02 8.7E-03 

Pm-147 1.6E-02 6.2E+01 

Pm-149 2.8E+01 3.6E-02 

5-39 
Table 5-5, Continued. 

DCFb DRLb,c 

Radionuclide rem per 

pCi · cm·3 • h 

p.Ci · cm"3 • h 

Pm-151 5.5E+02 1.8E-03 

S_m-151 2.1E-02 4.9E+01 

Eu-152 1.5E+01 6.7E-02 

Eu-154 4.8E+03 2.1E-04 

Eu-155 2.8E+02 3.5E-03 

Gd-153 5.0E+02 2.0E-03 

Tb-160 4.1E+03 2.4E-04 

Ho-166m 6.5E+03 1.5E-04 

Tm-170 2.4E+01 4.1E-02 

Yb-169 1.3E+03 7.4E-04 

Hf-181 2.2E+03 4.5E-04 

Ta-182 4.8E+03 2.1E-04 

W-187 6.6E+02 1.5E-03 

Ir-192 3.4E+03 3.0E-04 

Au-198 1.1E+03 9.5E-04 

Hg-203 9.6E+02 l.OE-03 

Tl-204 5.1E+00 2.0E-01 

Pb-210 1.2E+01 8.5E-02 

Bi-207 6.0E+03 1.7E-:.04 

Bi-210 O.OE+OO O.OE+OO 

Po-210 3.4E-02 3.0E+01 

Ra-226 3.0E+01 3.3E-02 

Ac-227 8.4E-01 1.2E+00 

_Ac-228 3.3E+02 3.0E-03 

Th-227 4.3E+02 2.3E-03 

Th-228 l.lE+Ol 9.2E-02 

Th-230 3.6E+00 2.8E-01 

Th-232 2.6E+00 3.8E-01 

Pa-231 1.4E+02 7.1E-03 

U-232 4.1E+00 2.5E-01 

5-40 

Table 5-5, Continued. 

DCFb· DRLb,c 

Radionuclide rem per pCi · cm~3 • h 

pCi · cm·3 • h 

I 

U-233 2.0E+00 5.1E-Ol 


U-234 3.2E+00 3.1E-Ol · 


U-235 6.7E+02 1.5E-03 


U-236 2.9E+00 3.5E-01 
 I 

U-238 2.5E+00 3.9E-Ol 

U-240 3.3E+00 3.0E-Ol 


Np-237 1.3E+02 7.8E-03 


Np-239 4.5E+02 2.2E-03, ·. 


Pu-236 3.9E+00 2.6E-Ol 


Pu-238 3.4E+00 3.0E-01 


Pu-239 1.5E+00 6.7E-Ol 


Pu-240 3.2E+00 3.1E-Ol 


Pu-241 O.OE+OO O.OE+OO 


Pu-242 2.7E+00 3.7E-01 


Am.-241 1.2E+02 8.5E-03 · 


Am-242m l.lE+Ol 9.2E-02 


Am-243 2.6E+02 3.8E-03 


Cm-242 3.7E+00 2.7E-Ol 


Cm-243 5.8E+02 1.7E-03 


Cm-244 3.3E+00 3.1E-01 


Cm-245 3.4E+02 a.oE-oa 


Cm-246 2.9E+00 3.5E-01. 


Cf-252 2.5E+00 4.0E-Ol 


8

Entries are calculated for gamma exposure at 1 meter above the ground surface (D0-88). 

bAll radioactivity is assumed to be deposited at the beginning of the incident. Deposition velocities 

are taken as 1 em· sec·1 for radioiodines and 0.1 em· sec·1 for other radionuclides. (Seep·. 5-24). 

eAssumes a PAG of 1 rem committed effective dose equivalent. 

dContributions from short-lived daughters are included in the factors for parent radionuclides. 

5-41 

References 

D0-88 U.S. Department of Energy. External 

Dose-Rate Conversion Factors for Calculation 

of Dose to the Public, DOE/EH- 0070, U.S. 

Department of Energy, Washington (1988). 

D0-90 U.S. Department of Energy. 

Effectiveness of Sheltering in Buildings and 

Vehicles for Plutonium. DOE/EH-0159, U.S. 

Department of Energy, Washington (1990). 

EP-78a U.S. Environmental Protection 

Agency. Protective Action Evaluation Part I ­

The Effectiveness of Sheltering as a Protective 

Action Against Nuclear Accidents Involving 

Gaseous Releases. EPA 520/1-78-00lA, U.S. 

Environmental Protection Agency, 

Washington (1978). 

EP-78b U.S. Environmental Protection 

Agency. Protective Action Evaluation Part II ­

Evacuation and Sheltering as Protectiv~ 

Actions Against Nuclear Accidents Involving 

Gaseous Releases. EPA 520/1-78-001B, U.S. 

Environmental Protection Agency, 

Washington (1978). 

EP-88 U.S. Environmental Protection Agency. 

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. U.S.' Environmental 

Protection Agency, Washington (1988). 

FD-82 U. S. Department ' of Health and 

Human Services, Food and Drug 

Administration. Potassium Iodide as a 

Thyroid-Blocking Agent in a Radiation 

Emergency: Final Recommendations on Use. 

Federal Register, 47, 28158; June 29, 1982. 

FE-85 Federal Emergency Management 

Agency. Federal Radiological Emergency 

Response Plan. Federal Register, 50, 46542; 

November 8, 1985. 

HA-75 Hans, J.M. Jr., and Sell, T.C. 

Evacuation Risks An Evaluation. 

EPA-520/6-74-002, U.S. Environmental 

Protection Agency, Washington, (1975). 

IC-75 International Commission On 

Radiological Protection. Report of the Task 

Group on Reference Man. ICRP Publication 

23, Pergamon Press, New York, (1975). 

NR-75 U.S. Nuclear Regulatory Commission. 

An Assessment of Accident Risks in U.S. 

Commercial Nuclear Power Plants. 

WASH-1400, U.S. Nuclear Regulatory 

Commission, Washington, (1~75). 

. NR-78 U.S. Nuclear Regulatory Commission 

and U.S. Environmental Protection Agency. 

Task Force Report. Planning Basis for the 

Development of State and Local Government 

Radiological Emergency Response Plans in 

Support of Light Water Nuclear Powet: Plants. 

NUREG-0396 or EPA-520/1-78-016, U.S. 

Environmental Protection Agency, 

Washington, (1978). 

NR-80 U.S. Nuclear Regulatory Commission. 

Criteria for Preparation and Evaluation of 

Radiological Emergency Response Plans and 

Preparedness in Support of Nuclear Power 

Plants. NUREG-0654, FEMA-REP-1, Rev.l., 

Washington, (1980). 

NR-88 U.S. Nuclear Regulatory Commission. 

A Regulatory Analysis on Emergency 

Preparedness for Fuel Cycle and Other 

Radioactive Material Licensees. NUREG1140, U.S. Nuclear Regulatory Commission, 

Washington, (1988). 

NR-89 U.S. Nuclear Regulatioy Commission. 

Appendix E - Emergency Planning and 

Preparedness for Production and Utilization 

Facilities. Title 10, CFR Part 50, U.S. 

Nuclear Regulatory Commission, Washington, 

(1975). 

NR-89a U.S. Nuclear Regulatory Commission. 

Severe Accident Risks: An Assessment for 

Five U.S. Nuclear Power Plants. NUREG1150, U.S. Nuclear Regulatory Commission, 

Washington, (1990). · 

5-42 

CHAPTER6 

Implementing the PAGs for the Intermediate Phase 

(Food and Water) 

See Chapter 3 and Appendix D for Current Implementation 


Recommendations for Food. Also refer to the 


following documents: 


Federal Emergency Management Agency 


Guidance Memorandum IN-1. The Ingestion Exposure 


Pathway. February 26, 1988 Federal Emergency 


Management Agency. Washington, DC 20472 


Guidance on Offsite Emergency Radiation Measurement Systems 


Phase 2, The Milk Pathway, FEMA REP-12, September 1987. 


Guidance on Offsite Emergency Radiation Measurement Systems. 


·Phase 3, Water and Non-Dairy Food Pathway, September 1989. 


6-1 


Background for Protective Action 

·Recommendations: Accidental 

Radioactive Contamination of 

Food and Animal Feeds 

B. Shleien, Pharm.D. 


G.D. Schmidt 


Office of the Bureau Director 


and 

R. P. Chiacchierini, Ph.D. 


Division of BioiO@ical· Effects 


WHO Collaborating Centers for: BRH • Standardization of Protection

Against Nonionizing Radiations 

Ill-.. of·~ hillllth • Training and General Tasks in 

·~· Radiation /'v\edicine 

• Nuclear /'v\edicine 

August 1982 

U.S. DEPARTMENT OF HEALTH AND HUMAN SERVICES 

Public Health Service 


Food and Drug Administration 


Bureau of Radiological Health 


Rockville, Maryland 20857 

FOREWORD 

The Bureau of R~ological Health develops and carries out a national program to 

control unnecessary human e~tre to potentially hazardous·. ionizil;lg and nonionizing 

radlations and to ensure the safe, efficac:ious use of such radiations. The Bureau publishes 

the results of its work in scientific journals and in its own technical reports. 

These reports provide a mechanism for disseminating results of Bureau and contractor 

projects. They are distributed to Federal; State, and local governments; industry; hos-. 

pitals; the medical profession; educators; researchers; .libraries; professional and trade 

organizations; the press; and others. The reports are sold by the Government Printing 

Office and/or the National Technical Information Service;. 

The Bureau also makes its technical reports.available to the World Health Organization. 

Under a memorandum of agreement between WHO and the Department of Health and 

Human Services, three WHO Collaborating Centers have been established within the Bureau 

of Radiological Health, PDA: 

WHO Collaborating Center for· Standardization of Protection Against Nonionizing 

Radiations; 

WHO Collaborating Center for Training and General Tasks in Radiation Medicine; and 

WHO Collaborating Center for Nuclear Medicine. 

Please report errors or omissions to the Bureau. Your comments and requests fo~ 

ftrther information are also encouraged. 

irector 

Bureau of Radiological Health 

ii 
PREP ACE 

By. FEDERAL REGISTER action of March 11, 1982 (47 FR 107,8), the Federal Emergency Management Agency (FEMA) oudined the r~ponsibilities of several Federal agencies 

concerning emergency response planning guidance that the agencies should provide to State 

and local authorities. This updated a prior notice published in the FEDERAL REGISTER by 

the General Services Administration (GSA) on December 24, 197' (40 FR 59494), on the 

same subject. GSA responsibilitY for emergency management was transferred by Executive 

Order to FEMA. The Department of Health and Human Services (HHS) is responsible for 

assisting State and local authorities in developing plans for preventing adverse effects from 

exposure to radiation in the event that radioactivity is released into the environment. This 

includes developing and specifying protective actions and associated guidance to State and 

local governments for human food and animal feeds .. 

Proposed reCommendations were published in the FEDERAL REGISTER on December 15, 

1978 (43 FR 58790) and a background document accompanied their publication. Twenty-one 

comment letters were received in response to the proposal in addition· to comments from 

various Federal agencies. Review of these comments led to changes in the recommendations and supporting rationale, dosimetric and agricultural· models, and cost/benefit analysis. 

These changes have been incorporated into this.background document, which is intended to 

accompany and support FDA's final recommendations on Accidental Radioactive 

Contamination of Human Foods and Animal Feeds: Recommendations for State and Local 

Agencies. The final recommendations will appear in the FEDERAL REGISTER~ 

This background report discusses the rationale for the Protective Action Guides; the 

dosimetric and agricultural ·models used in their calculation; some methods of analysis for 

radionuclide determination; appropriate protective actions; and cost considerations. 

Bernard Shleien, Pharm. D. 

Assistant Director for 

Scientific Affairs 

Bureau of Radiological Health 

iii 
ABSTRACT 

Shlelen, B., G.O. Schmidt, and R.P. Chiacehierini. Background for Protective Action 

Recommendations: Accidental Radioactive Contamination of Food and Animal Feeds. HHS 

Publicadon FDA 82-81.96 (August 1982) (pp. 44). 

This report provides background material for the development of FDA's 

Protective Acdon Recommendadons: Accidental Radioactive Contamination 

of Food and Animal Feeds. The rationale,. dosimetr:ic and agricul rural transport 

models for the Protective Action Guides are presented, along with information 

on dietary intake. In addition' the document contains a discussion of :fie1.Q. 

methods o:f analysis of radionuclides deposited on the ground or contained 

in milk and herbage. Various protective ac.tions are described and evaluated, 

and a cost-effectiveness analysis for recommendations performed. 

The opinions and statement$ contained in this report may not 

necessarily represent the •views or the stated policy of the World 

Health Organization (WHO). The mention of commercial products, 

their sources, or their use in connection with material reported 

herein is not to be construed as either an actual or implied 

endorsement of such products by th4[t Department' of Health . and 

Human Ses:"vices (HHS) or the. World Health.Organization. · 

iv 
CONTENTS 


Page 

Foreword • • • • • • • • • • • • • $ • • • • • • • • • • • • • • • ii

Preface . . . . . . . . . . . . . . . . . . . . . .. . . . . . . . iii 


Abstract . . . . . . . . . . . . . . . . . . . . . . . .. . . . . iv 


Chapter 1. Rationale for Determination of the Protective Action Guides·· . . . 1 


1.1 Introduction • • • • • . . . . . . . . .. 1 


1.2 Models for Evaluation of Risk. . . . . . . . . . . . . . ' . . . . . . 1 


1. 2. 1 Somatic Risk evaluation • • . . . . . . . . . . . .. ~ . . . . 1

1.2.2 Genetic Risk Evaluation •• . . . . . . . . . . . . . . . 2 


1. 3 Assessment o:f Common Societal and Natural Backgromd 


Radiation Risks • • • • • • • • • • • - • • • • • • • .·• . . . . . 3 


1. 3. 1 Common Societal Risks • • • . . . . • • . . . . . . . . 1. 3. 2 Risks from Natural Radiation • . ... . • • • • • • • • • • • • 

1. 4 Preventive and Emergency PAG' s .• . . . . . . . . . . . . . . . .. . 5 


1.4.1 Preventive PAG . . . . . . . . . . . . . . . 6 


1•4. 2 Emergency PAG. . . . . . 7 


1.5 Evaluation of PAG Risks . . . . . . . 7 


Chapter 2. Dosimetric Models, Agricultural Transport Mode!s, 

Dietary Intake, and Calculations • ~ • • • • • • • • • . . . ~ . 8

2.1 Dosimetric Models . . . . . . . . . ~. . . . . . 8

2. 1. 1 Introduction • • • . . . -· . . . 8 

2. 1 • 2 Iodine-131 : Dose to Thyroid • • • • • • • • ' • • • • • • • 8 


2. 1. 3 Cesium~ 137 and -134: Dose to Whole· Body • • . . . 9 


2. 1. 4 S trol1tium: Dose to Bone Marrow • • • • • • • • • • • • • 10 


2.1.5 Other Radionuclides •••••• . . . 11 


2. 2 Agriculture Transport Models ~ • • • • • • • • • • • • • • • • • • • 12 


2.2.1 Transport Models •• 12 


2.2.2 Total Intake • . .. . . . . . . . . . 13 


2.2.3 Peak Concentration •• . . . . . . . . . 14­

2.3 Dietary Intake . . . . . . . . . . . . . . . 14­

2. 4 Calculations • . . . . . . . . . . . . . . . . . 15 


v 
• • • • 

• • • • • • • • • • • • • • • • • • • • • 

Page 

Chapter 3. Methods of Analyses for Radionucllde Determination • • • • • • • • 18 


3.1 IntrodtJCtion • . • • • • • • • • • • • • • • • • 
• • • • • • • • • • 18 

3.2 Determinations of Radionucllde Concentrations by 


Sensitive Laboratory Methods • • • • • • • • • • • • • • • • .. . .. 18 


3.3 Determinations of Radionucllde Concentrations by Field Methods 19 


3.3.1 Gro\l'ld Contaminaticn (Beta Radiation) • • • • • • • • • • • .. 19 


3.3.2 Herbage • • • • • • • • • • • • • • • • • • • • • • • • • • 20 


3.3.3 Mllk. • • • • • • • • • • • • • • • • • • • • • • • • • • • 21 


Chapter 4. Protective Actions • • • • • • • • • • • • • • • • • • • • • • • 26 


Chapter'· Cost Considerations • • • • • • • • • • • • • • • • • • • • . • • 31 


'·1 Cost/Benefit Al:Wysis • • • • • • • • • • • • • • • • • • • • • • • 31 


'.1. 1 lntroductiCX'I • • • • • • • • • • • • • • • • • • • • • • • • 31 


'.1.2 Benefit of Avoided Dose • • • • • • • • • • • • • • • • • • • 32 


'.1.3 Protec:tive Action Costs • • • • • • • • • • • • • • • • • • • 32 


'.1.4 Population Mllk Intake and Dose. • • • • • • • • • • • • • • • 33
 '.1., MJJk Concentration for Cost • Benefit • • • • • • • • • • • • • ·33 


5. 2 Economic ImpaCt • • • • • • • • • • • • • • • • • • • • • • • . . 
 '.3 Cost-Eff~veness Analysis . . .. . . .. . . . . . . . ... . •· 37 


'·4 Summary and Conc1Usion • • . . . . . . . . . . . . .. .. . .. . 
 References • • .. • • • • ·• • • 39 


vi 
CHAPTER 1. RATIONALE FOR DETERMINATION OF THE 


PROTECTIVE ACTION GUIDES 


1.1 INTRODUCTION 

The process of determining numerical limits f"' radiation standards is one of risk 

assessment. This process, in which risk considerations are .an important factor in decisionmaking, consists of two elements: determination of the probability that an event will occur, 

and determination of "~ceptable risk.11 A recent discussion of acceptable risk defines risk 

as a measu-e of the probability and severity of adverse effects. Safety is the degree to 

which risks _are judged acceptable (1). 

Since initiation of protective action assumes that an accident has occurred, no 

attention will be given to the estimation of probabilities for accident occurrence in the 

present analysis. 

One process of determining "acceptable risk'' is to compare estimates of risk associated 

with an actim with already prevalent or "natural" risks that are ~cepted by society. 

This method of evaluation is employed in the present dis~ion. by 9)mparing the risk 

from natural disasters and from the variation in "natural radiation backgromd" to· theradiation risk associated with the numerical limits for the Protective Ac;tion Guides (PAG). 

"Protective· action guide" (PAG) means the projected dose- commitment values to 

individuals in the general population that warrant protective action following a release of 

radioactive materiaL Protective action would be warranted if .the expected individual dose 

reduction is not offset by negative social, economic, or health effects. The PAG does· not 

include the dose that has ll\avoidably occurred prior to the ~essment. "Projected dose 

commitment" means the dose commitment that would be received in the future by individuals in the population group from the contaminating event if no protective action 

were taken. The projected dose commitment is expressed in the 1.K1it of dose equivalent or 

the rem. 

The "natu-al radiation background" consists of contributions from external radiation 

and internal deposited ·radioactivity from ingestion and inhalation. For the most part, the .	variation in the internal natu-al radiation dose is due to the variability of whole-body 

potassium-40. Since these PAG's are limited to ingestion, a parameter that describes the 

variability of the internal natural radiation dose migtH appear more appropriate than using 

the variability of the external or total natural radiation dose in evaluating the acceptability 

of a given level of risk. However, the potassium level in the body (and hence internal dose) 

is controlled by metabolic processes and dietary intake has little effect. Hence the risk of 

natu-al disasters, which is dependent on geographical location of residence, is in this 

agency's opinion a better meastre of acceptable risk. 

1.2 MODELS FOR EVALUATION OF RISK 

Models for the somatic and genetic effects of radiation are required for comparisons of 

radiation risks from the PAG's relative to other naturally occurring risks. 

1.2.1 Somatic Rlsk Evaluation 

A review of the current literature indicates that the risk estimates developed in the 

· National Academy of Science Committee on the Biological Effects of Ionizing Radiation or 

the BEIR-1 report (2) and the BEIR-111 report (3) are appropriate for use in analysis of 

1 

somatic risk. Mortality rather than incidence estimates are employed in the comparisons. 

In the case of comparisons to natural background radiation, use of mortality data or 

incidence estimates would yield the same numerical PAG limits, because these limits are 

based on a comparison between risks rather than an evaluation of absolute risk. 

The radiation doses in the event of a contaminating accident will most likely result from 

ingestion of the fission products cesium-134 and -137; strontium-89 and -90; and iodine-131. 

Por the purpose of this analysis it is assumed that all projected extra cancers can be 

attributed to i.nternal radiation via the food pathway (i.e., the r_isks from ingested 

radioactive material is the same as that fro.n external radiation). 

The BEIR-m (.3) best estimate of lifetime cancer risk (linear quadratic model) for a 

single exposll'e to low-dose, low LET radiation is from 0.77 to 2..26 x to-- deaths per personrem, depending on whether the absolute or relative-risk projection model is used (calculated 

from Table 1). The equivalent risk estimate from BEIR-1 (2) is 1.17 to 6.21 x 10_.. deaths 

per person-rem. 

Table 1. Risk estimates for single dose 

Deaths per million persons per 10 

rads single dose whole-body BEIR-111 

Dose response model Absolute risk Relat1ve risk 

Linear quadratic 766 22.5.5 

Linear 1671 5014 

Quadratic 9.5 276 

These risk estimates are for a single dose of 10 rem, because limitations of the scientific 

information do not justify estimates at lower doses according to the BEIR Committee. 

Because of the ll'lcertainty of risk estimates at low doses, BEIR-III provided risk estimates 

based on a linear model and a pure quadratic dose response model as well as estimates based 

on the preferred linear quadratic model. The risk estimates for the linear model are about 

a, factor of 2 higher and those of the cp.tadratic model and about a factor of 8 lower than 

those of the linear quadratic model. It should further be noted, that BEIR-m does not 

recommend that their risk estimates be extrapolated to lower doses because of the 

inadequacies of the scientific basis. BEIR-m does recognize however that Federal agencies 

have a need to estimate impacts at lower doses. While BEIR-lll prefers the linear-quadratic 

dose response model as the best estimate, regulatory agencies have continued to favor the 

linear model as the basis for making risk estimates. While the BEIR-m estimates will be 

used here to estimate the impact (health effects) at lower doses, it is fully recognized 

that current scientific opinion leaves alternatives as to whid'l dose response and risk model 

to use. 

As previously stated, for the purpose of setting PAG's, comparison of radiation risks to 

those from natural disasters is considered the approad'l of choice in this document. 

1.2.2 Genetic Risk Evaluation 

The model for genetic risks from radiation expos~.re is desaibed in the BEIR-III report 

(3). In the first generation, it is estimated that 1 rem of parental exposll'e throughout the 

general population will result in an increase of S to 7.5 additional serious genetic disorders 

per million liveoorn offspring. The precision for estimating genetic risks is less precise than 

those for somatic risks. Given the broad range, genetic risks are evaluated, but are not 

precise enough co be a basis for setting the PAG's. 

2 

1.3 	 ASSESSMENT OF COMMON SOCIETAL AND NATURAL BACKGROUND RADIATION RISKS 

1.3.1 Common Societal Risks 

As previously stated, one m•~thod of determining the acceptability of a risk is by 

comparing prevalent or normal risks from hazards common co society. A list of the annual 

risks from common societal hazards is given in Table 2. Comparision of radiation risks to 

commonly accepted societal risks :'ssumes that the age dependencies are similar and that all 

individuals are equally exposed tc- the hazard. This latter aSsumption is, of course, not 

entirely valid in that persons near~~ a nuclear power plant or a dam, or in an earthquake or 

tornado area might be expected to be at greater risk than persons living at a distance from 

the particular hazard. 

Table 2. Annual risk of death from hazards common to society 

Risk of death 

Category Reference (per person per year) 

An disease (4) 8 x to-3 

Leukemia and all otJ,er cancer (.5) 1.5 X t0- 3 

Motor vehicle accidents (6) 3 X tO-It 

Accidental poisoning (6) t x to-s 

Air travel (7) 9 X t0- 6 

Tornadoes (Midwest) (8) 2 X to-G 

Earthqual<es (Calif. ) (8) 2 x to- 6·­

Floods ( 46 million at risk) (9) 2.2 X t0-6 

Catastrophic accidents 

(tornadoes, floods, 

hurricanes, etc. ) (10) t.2 X t0- 6 

Natural disasters (11) 9 X t0- 7 

(6) 8 X t- 7 

Tornadoes 	 (7) 0.4 X t0- 6 

(9) 0.6 X t0- 6 

Hurricanes (7) 0.4 X t0- 6 

(9) 0.3 X to-& 

Floods (8) 2 X t0-6 

o.s x to-: 

Lightning ~fJ 0 • .5 X t0­

Winter storms (9) 0.4 X 10- 6 

Natural disasters (sum of above) 	 2.1 to 3.9 x 10- 6 

Table 2 indicates that the annual individual risk from natural disasters is approximately 

1 to 4 x to-'. This risk represents a common risk level, which is generally not considered 

in selecting place of residence. At this level of risk, some action to prevent further loss of 

life could be expected by society following the occurrence of a natural disaster.. It thus 

appears prudent to evaluate the somatic risks from radiation in relation to the risk of death 

from a natural disaster. For comparison purposes, a value of 1 in a million (1 x 10- 6

) annual risk of death, which is often quoted as an acceptable risk, will be used as the risk of 

natural disasters. Actual data indicate that the risk of natural disasters may be a 2 or 3 

times greater risk than this value. For a risk of death of 1 x to- 6 per year, the lifetime 

accepted societal risk would be about 70 x 10- 6

• This is equivalent to a single radiation 

dose of 14'0 to 420 mrem, using the linear model, or 310 to 910 mrem using the BEIR-111 

linear quadratic model (see Table 1). The upper and lower ranges are those obtained from 

employment of relative and absolute risk models and the dose response extrapolations 

mentioned above (from calculations based on data in Table 1). Genetic effects are not 

considered in evaluating common societal hazards because of the difficulty in assessing 

3 

deaths occurring from genetic consequences, either natural or radiat~on induced.. If spontaneous abortions are deleted from this category, then fatal genetic effects are a small 

portion of the overall genetic impact on health. However, it is difficult to accurately 

evaluate genetic effects, and even more difficult to compare its impact to the impact of 

somatic effects ln an effective manner. 

1.3.2 Risks Prom Nattral Radiation 

Ptrther perspective on acceptable risk can be obtained by examining the risks of natt.ral 

backgrotl'\d radiation. In risk assessments where a radiation risk is compared co that from 

the nattral radiation b..ckgrotrtd, the question is which variable assodated with natural 

backgrotrtd should be used to determine "acceptable risk?" Since backgrol.81d radiation has 

always been a parr of the nattral environment, a plausible argument might be to assume 

that the risks associated with the average natt.ral radiation dose represent an "acceptable 

risk." 

It has also been argued that because of the ever present risk from natt.ral radiation, a 

level of manmade radiation ought to be acceptable if it is "small". compared to natt.ral 

backgrol.81d (12). It has been suggested that "small" be taken as the standard deviation of 

the population-weighted natural backgrol.81d (13). ln previous evaluations that led to the 

FDA's proposed PAG recommendations (14) the geographic variable (two standard 

deviations) in the· natural radiation dose was used as a point of comparison for judging 

acceptable radiation risk (1,). This value, calculated on a State-by-State basis assuming a 

"'log-normal distribution and not weighted for population, is 8..5 mrem per year. The 

cumulative lifetime: dose· equivalent would thus be about ..500 mrem, which was the basis for 

the proposed PAG recommendation for the whole body at the Preventive PAG level. The 

Environmental Protection Agency (EPA), in a further analysis a1 previously published data. 

(16), has calculated the cumulative distribution of dose equivalent in the U.S. population. 

These data show that 9S percent of the population receives between 28 and 84 mrem/year 

from cosmic and terresrr:ial background radiation (17). The actual distribution is 

asymmetric and not log-normal. Thus, one-half a1 this 9S-percent increment range, or 28 

mrem/year, will be· taken as the value for judging acceptable risk.. Adler (13) notes that one 

standard deviation of the natural external and internal radiation background derived from 

earlier sources (18) is 20 mrem. Personal conversations with Adler revealed that this 

estimate is based on air exposures rather than dose equivalent (mean whole body) and 

involved a broad rounding off of values. At the 9..5-percem increment value (latest EPA 

data) of 28 mrem/year (19), the additional lifetime dose over 70 years is about 2000 mrem. 

About 6 million persons (2-1/2 percent of the population) receive lifetime dosf!S that exceed 

the mean backgrol.81d radiation dose by this amount or more. 

Another possibility, especially applicable co setting limits for internal emitters, is using 

the variation in internal natural radiation dose as a reference for es tabllshing an acceptable 

standard for PAG's. For PAG limits for radionuclides via the ingestion pathway, doses to 

organs other than the ltrtgs are most pertinent. Using this suggestion still requires a 

judgmental decision as to whether the variation in internal natural radiation dose is "small." 

A summary of internal natt.ral radiation doses is given in Table .3. It is apparent that 

natural radiation doses to human tissues and organs is determined mainly by potassium-40 

concentration. The average annual internal whole-body radiation dose per person from 

ingested natural radioactivity is 19.6 mrem, a1 which 17 mrem is due to potassium-40. 

In potassium-l.f.O whole-body measurements of 10,000 persons, a standard deviation of 

about 12 percent (9.5-percent confidence level of 23•..52 percent) was observed (20). The 

study further concluded that the standard deviation is also the same for different groups of 

age and sex, and therefore, it may be concluded that the same biological variadon exists for 

all the different age-sex groups. In another study based on the chemical determinations of 

total body potassium the average amount in a 70-kg man was estimated co be 136 g with a 

standard deviation of.± 28 g or ±20 percent (9..5-percem confidence increment of ± 40 

percent) (21). 

4 

Table 3. Annual internal radiation dose per person for non-inhaled natural raciioactivitya 

Amual dose (mrads/year) whole-body average 

{unless otherwise noted) , 

H-3 0.001 

Be-7 0.008 

C-14 1. 3 

Na-22 0.02 

K-40 17 

Rb-87 0.4 

U-238-U-234 series 0.043b 

Ra-222 0.064b 

Po-210 0.7 

Ra-226 O.OJlb 

Th-2JO 0.04~ Th-232 0.04 

Total 19.6S 

aouNSCEAR 0977). · 

baased on soft tissue dose (lmg, testes, and ovaries) 

An indirect means of determining the variability of whole-body potassium vatues is 

based on the constant ratio of mean potassium values to total body water up to age !SO 

(20). The 95--percenr: confidence inaemenr: for the variability o~ total body water in males, 

ages 16 to 90 is 16 percent, while for females it is 13 percent for ages 16 to 30 and 21 

percent for ages Jl to 90 (22). 

From the above data, h: appe~s that the increment for. the 9S-percent confidence 

level for whole-body potassium, and hence potassium-40, is between t 15 percent and t 40 

percent. Note that this variability may be due to differences in body water or body weight... 

Only in the case of one study (21) is it clear the total body weight is considered. a constant. 

It is apparent that a range of values between approximately 3 to 7 mrad per year may be 

used to describe the variability in natural potassium-40 dose to the population on a wholebody dosimetric basis. The mid-point of this range is 5 mrad per year or a lifetime dose 

commitment (70 years) of 350 mrem. . . ' 

Thus, the lifetime radiation dose associated with the variability in narural.radiation is 

about 350 mrem (internal) and 2000 mrem (external). 

1.4 PREVENTIVE AND EMERGENCY PAG'S 

PAG's have been proposed for two levels of response: 

1. Preventive PAG - applicable to situations where protective actions causing 

minimal impact on the food supply are appropriate. A preventive PAG establishes a level at 

which responsible officials should take protective action to prevent or reduce the 

concentration of radioactivity in food or animal feed. 

2. Emergency PAG- applicable co incidentS where protective actions of great impact 

on the food supply are justified because of the projected health hazards. An Emergency 

PAG establishes a level at which responsible officials should isolate food containing 

radioactivity to prevent its introduction into commerce, and at whidl the responsible officials must determine whether condemnation or another disposition is appropriate. 

5 

1.4.1 Preventive PAG 

During recent years numerous reports on risks and risk/benefit assessments for me 

eva1tm.tion of technological insults have been published. A number of these have conduded 

that an annual risk of death of 1 ln a million is acceptable to the public (8). The total average annual risk to me U.S. population from natural disasters appears to be about 2 or 3 

times greater man the 1 in a million annual risk. Those individuals living in certain flood 

plains, tornado, or earthquake areas accept risks that may be greater than the average by a 

factc~r of 2 or more (See data for tornadoes and earthquakes ln Table 2). 

As previously mentioned, based on BEIR-UI (.3) upper risk estimates, a 1 in a million annual risk of death corresponds to a single radiation dose of 140 to 910 mrem. 

It is our conclusion that an annual risk of 1 in a million provides a proper perspective for 

setting food protective actions guides (PAG's) for radiation contamination acddents of low 

probablllty. It appears that most individuals in the United States will never be exposed to 

such a radiation contamination acddent and that any one individual is not likely to be 

potentially exposed more than once in his lifetime. 

Based on the above considerations, the uncertainty in radiation risk estimates and the 

uncertainty in the average nattral disaster risks, a value of 0., rem whole body is selected 

for the Preventive PAG. Thus, at projected doses of 0., rem from Q)ntaminated food, lt is 

recommended that protective actions having low impacts be taken for protection of the 

public. The specific value of 0., &·em represents a judgment decision rather than a specifically derived value from specific models and assumptions. 

Ftrther perspective on acceptable risks for setting the PAG's is the risks associated with 

nattral background radiation. The discussion above indicates that lifetime dose associated 

with me 95-percent increment of the variability in natural radiation is about 350 mrem 

internal and 2000 mrem external (that is, 2-1/2 percent of the population receives doses 

greater man the average by amount or more). 

This Preventive PAG is applicable to whole-body radiation exposure and to major' 

portions of me body including active marrow (ingestion of strontium) ln conformity with 

current U.S. radiation protection practice. Coincidently, o.s rem is me Federal Radiation 

Cooncll's (FRC) annual limit for individuals of the general populadon (23) .. 

Present convention, rec:Ommended by the Federal Radiation Council (23) based on prior 

estimates of relative radiation risks for various organs indicates that radiation limits for the 

thyroid gland be set at .3 times those for the whole body. More recent sdentific information 

indicates that the risks from organ doses relative to whole body differ from those assumed 

when the current U.S. regulations and FRC guidance were established. The International 

Commission on Radiological Protection (ICRP) in revising its recommendations on internal 

expostre derived weighting factors mat represent the ratio of rislc from irradiation to a 

given tissue (organ) to the total cancer risk due to uniform irradiadon to the whole body. 

The ICRP weighting factors are 0.12 for red bone marrow and 0.0.3 for thyroid, indicating 

that the cancer risk is 8 times less for red bone marrow and 33 times less for thyroid than 

for whole body exposure (24). Further considerations of effects other than cancer resulted 

in the limitation of organ doses to 50 rems per year for occupational workers. Thus the 

ICRP recommendations in effect provide for or allow single organ doses that are 8 times 

greater for red bone marrow and 10 times greater for thyroid than f,or whole body. The EPA 

has recently proposed Federal guidance for occupational radiation protection that incorporates the basic ICRP recommendations (46 FR 78.36, Jan. 2.3, 1980). Setting the Preventive 

PAG at O.S rem for whole body and red bone marrow and 1.5 rem for thyroid provides 

significantly more protection from me actual risks of organ doses than from whole-body 

risks. To the extent that the whole-body risk is considered acceptable, the red bone marrow 

and thyroid limits are conservative by factors-of 8 and 3.3, respectively. 

6 

l.lf..2 Emergency PACi 

The philosophy of the protective action guidance of FDA is that low impact protective 

actions should be initiated when contamination of food exceeds the Preventive PAG. The 

intent is that such protective actions be implemented to prevent the appearance of 

radioactivity in food at levels that would require the condemnation of food. If such actions 

are ineffective, or high levels appear in food, then the Emergency PAG is that level at 

which higher impact (cost) protective actions are warranted. At the Emergency PAG 

radiation level, action should be taken to isolate and preven·t the introduction of such food 

into commerce and to determine whether condemnation or other disposition is appropriate. 

With regard to the numerical relationship between the Preventive PAG level and the 

Emergency PAG level, prior conventions may be considered. For example, the Federal 

Radiation Council (23) assumed that tf:te dose to the most highly exposed individual does not 

vary from the average dose to the whole population by a factor greater than three; Hence, a 

factor of 3 was used to define the difference between maximum and average population 

limits. Traditionally, it has been more common to use a factor of 10 as a safety factor, 

such as between occupational and general public limits. A factor of 10 difference between 

the Emergency and Preventive PAG levels, based on these traditional radiation protection 

approaches has in the past been thought to introduce a sufficient level of conservatism. The 

proposed PAG's (14) adopted this rationale in setting the Emergency PAG's. The analyses of 

costs, to follow, also indicate that a factor of 10 between the Preventive PAG and 

Emergency PAG is appropriate. As calculated in the last chapter of this report the cost of 

condemnation of milk (high impact protective action) is about a factor. of 10 greater than 

the· cost of using uncontaminated stored feed Qow impact protective action). Since 

contamination of the milk pathway is considered to be· the most probable and significant 

food problem, this is the only pathway that is cost analyzed. 

The use of a factor of 10 adopted here results· in an Emergency PAG of' rem for the 

whole body which numerically is equivalent to the current occupational annual limit. This 

limit permitted each year over. a working lifetime is associated with the expectation of 

minimal increased radiation risks. 

1., EVALUATION OP PAG RISKS 

The risks associated with a radiation dose equal to the PAG's can be readily calculated 

from the BEIR-111 risk estimates in Table 1. For the Preventive PAG of 0., rem, the deaths 

per million persons exposed are one-twentieth of those given for the 10-rad single dose (or 

about 38 to 2.50 deaths for the linear quadratic and linear models respectively). On an 

individual basis, this is a risk of death of 0.38 to 2.'0 x to-tt (0.0038 to 0.02' percent) 

over a lifetime. BEIR-ut gives the expectation of cancer deaths in the U.S. population 

as 167,000 per million or an individual expectation of cancer death of 16.7 percent. 

As noted above, the BEIR-ut estimate of serious first generation genetic disorders is 5 co 

7'per million live offspring per rem of parental expostre. Thus, for a dose of 0 • .5 rem, the 

expectation is 2.' to 38 disorders per million live offspring. BEIR-ut notes the current 

estimate of the incidence of serious human disorders of genetic origin as roughly 10 percent 

of liveborn offspring. 

7 

CHAPTER 2. DOSIMETRIC MODELS, AGRICULTURAL TRANSPORT MODELS, 


DIETARY INTAKE, AND CALCULATIONS 


2.1 DOSIMETRIC MODELS 

2.1.1 IntrOduction 

The dosimetric models and metabolic parameters f<X" estimating the dose from internally 

deposited radionuclldes are in a state of flux. The recent reporcs and current activity 

represent the first major revision since the adoption of ICRP Publication 2 (2.5) and NCRP 

Report 22 (26) in 19.59. ICRP Publication 30 (27) superseded ICRP Publication 2 and revised 

the basic approach in setting limitS f<X" intake of radionuclldes by workers. The ICRP recommendations are intended to avoid nonstochastic effects and to limit the occurrence of 

stochastic effects to an acceptable level. This approach includes the use of weighting 

factors to sum the risk from organ doses in setting the limitS for intakes. This system 

contrasts with the earlier approach where limits were based on the dose to· the "aitical 

organ... · 

The ICRP Publication 30 approach has considerable merit, but is not yet widely 'accepted 

In the United Scates. Irs use in calculating the derived response lwels would represent a 

major change. Accordingly, the approach is to use the organ to whole-body dose relationship of current U.S. regulations and to select aitical organ dose conversion factors that are 

based on current dosimetric models and metabolic parameters. Where apropriate, the 

recent ICRP and NCRP organ dose models wlll be accepted as representing current scientific opinion. It should be noted that future reports and revisions by NCRP, MIRD (Medical 

Internal Radiation Dose Committee of The Society of Nuclear Medicine) and other Federal 

agencies may necessitate a revision of the dose conversion values selected here. 

The PAG's are applicable to the most aitical or sensitive segment of the population. In 

most cases this means that :the infant or child is the critical segment. In r:he case of the 

Emergency PAG, derived response levels are also presented for the adults. This permits 

greater flexibility in the choice of protective actions in cases where infantS are not present 

or can be excluded from use of the specific food item being considered. 

2.1.2 Todine-131: Dose To n.yroid 

Petal uptake of iodine begins at about the 9th week of gestation and reaches a maximum 

in the newborn infant (28,29) before returning to adult levels. , Kereiakes et a1. (30) report 

that thyroid uptaJ<e during the first 2 weeks of life is very high and report a value of 70 

percent of that administered for the newborn. The radioiodine uptake expressed per Unit 

thyroid weight remains high for the newborn and infant and only gradually decreases 

throughout childhood and adolescence to adult levels. The newborn infant will be taken as 

the most critical segment of the population because factors concerning intake, uptake, and 

radiosensitivity indicate that the thyroid gland of an infant receives a higher radiar:ion dose 

per unit 1-131 ingested than any other age group (30). However, it is interesting to note that 

data indicate that only about 3 percent of infants are given whole cow's milk at 1 month of 

age and about 1 percent at 10 days (31). Hence, assuming that all infants are given whole 

milk provides a conservative estimate of infant thyroid doses. 

Data on the dose to the fetal thyroid from I-131 ingested by the mother is rather limited. The study of Dyer and Brill (29) reports an increase in the fetal thyroid dose from 0.7 ro 

5.9 rads per lJ Ci administered to the mother for fetal ages of 13 co 22 weeks. It thus 

8 

appean that the fetal thyroid dose is less than that of the newborn infant ingesting I-131 

contaminated milk. · 

The current literature on normal thyroid uptake in U.S. adults shows .24-hour 'Jptake has 

decreased from about 30 percent reported in the 1960's to about 20 percent or less in current comparable studies. Kereiakes et al~ (32) use a 20-percent uptake for all ages. This 

reduced uptake apparently results from changes in the U.S. diet, whereas ICRP 30 (27) has 

continued to use an uptake of ~0 percent to reflect world averages. , 

The Medical Internal Radiation Dose (MIRD) Committee schema (33) has be ~n used by 

Wellman and Anger (34) to calculate dose factors per 1JCl ingested for the newb1rn for the 

1-, .5-, 10-, and 1.5-year-old child, and for the adult. These factors were then modified by 

Kereiakes et al. (32) to reflect a 20-percent uptake for all ages.o A biological half-life of 68 

days is used for all ages, which results in an effective half-life of 7.2 days. Although there 

is some evidence that the biological half-life for the infant is less, the radiation dose is 

largely controlled by the radiological half-life and use of a single value appears appropriate 

here. Because of some uncertainty regarding the fetal thyroid dose and lack of acceptance 

by national and international groups, the older data (27-percent uptake) of Wellman and 

Anger (34) will be used. This provides some additional conservatism in the derived response 

levels for I-131. The cumulative activity is 2.08 )JCi-days per )JCi ingested 

(administered). 

Table 4. Summary of I-131 dose conversion factors 

Age Thyroid weight (g) Dose rad/ uCi 

Newborn 1 • .5 16.0 

1 yr. 2.2 10.9 

4.7 	 .5.1 ' yrs. 10 yrs. &.0 	 3.0 

1.5 	 yrs. 11.2 2.1 

Adult 16.0 1 • .5•. 

For the infant and adult, the dose conversion factors to be used are 16.0 and 1 • .5 rad/)JCi 

ingested. 

2.1.3 Cesium-137 and-134: Dose To Whole Body 

The NCRP (3.5) has reviewed the behavior of Cs-137 in the environment and its metabolism and dose to man. From studies of Cs-137 in food chains, the biological half-life is 

found to vary from 1.5 t.5 days in infants to 100 t.5 days in adults. The biological halflife in pregnant women is reported to be 1/2 to 2/3 that in nonpregnant women and 

consequently the dose to the fetus is also reduced. . 

Retention of Cs-1.37 in the adult is stated to be well represented by a 2-exponential 

equation with biological half-times of 1.4 days and 13.5 days applicable to retention in body 

fluid and soft tissues, respectively. Integration of this equation yields an accumulated activity of 170 )JCi-days per J,1Cl of intake. This accumulated activity may be expressed in 

terms of a single retention function yielding a value of 118 days. 

The dosimetry of internally deposited Cs-137 in infants and adults is treated separately 

for the beta particle and photon components. The difference between infants and adults is a 

smaller photon contribution to the infant because of the smaller body size. For a uniform 

concentration of 1 )JCl/kg of body weight, the total beta and photon dose rate is 19 

mrad/day to the infant and 2S mrad/day to the adult. Use of the above accumulated activity factor of 170 )JCi-days per )JCi intake yields a dose of 0.061 rad/)JCl intake for the 

adult. Assuming an effective retention time of 20 days· for the infant, the corresponding 

factor for the infant is 0.071 rad/)JCi intake. The use of a smaller effective retention 

9 

time (15 days as noted in NCRP (26)) or 10 days as used in NUREG-0172 (36) would reduce 

the infant dose conversion factor. The use of 20 days thus tends to overestimate the infant 

dose. 

It is a.l!o important to consider the dose from Cs-134 which, depending on operating 

history, occurs in nuclear reactor fuel at levels equal to or greater than that of Cs-137. 

Unfortmately, published dosimetry data for Cs-134 for the infant are rather limited. 

Conversion factors for the adult that use current models and metabolic data are found in 

ORNL/NUREG/TM-190 (37). Johnson et al. (38) have used this same data base to compute 

committed effective dose equivalent conversion factors for both infantS and adultS. The 

mean absorbed dose per cumulated activity factor for the infant were modified by the ratio 

of adult and infant organ mass (with a further correction to photon component based on 

absorbed fraction) to produce the infant factors. It was stated that this procedure may 

underestimate the infant dose. 

The approad1 adopted here will be to modify the adult dose conversion factor in 

ORNL/NUREG/TM-190 {37) based only on relative body weight and cumulated activity 

(effective retention half.:times}. The dose conversion factor for cesium-134 from 

ORNL/NUREG/TM-190 adult whole body is 0.068 rem/].1 Cl ingested and the estimated 

factor for the infant is then 0.118 remh1Ci ingested. This value should overestimate the 

Infant dose and is conservative. 

Summary of Cs-1:31f. and C.s-137 Dose Conversion Factors 

Table 5. Summary of dose factors for Cs-131f. and Cs-137 

Infant Adult 

Body Mass 7,700g 70,000g 

Uptake to whole body& 

T biological (days) 

1.0 

20 

1.0 

118 

T effective Cs-1:34 (days) 19.5 102 

Cs-1:37 {days) 20 118 

Dose conversion (rem/l.l Ci ingestion) 

Cs-1:34 0.118 0.068 

Cs-137 0.071 0.061 

¥or cesium-1:31f., ORNL/NUREG/TM-190 uses uptake of 0.9.5. 

2.1.4 Strontium: Dose To Bone Marrow 

The tissues a& greatest risk in the skeleton have been identified as the active red marrow 

ln trabecular bone and endosteal cells near bone surfaces (generally referred to as bone 

strface). Spiers and his coworkers (:39,40) have developed methods to calculate the absorbed 

doses, Dm and D5, received by red marrow and bone surfaces, respectively from betaemitting radionuclides uniformly distributed throughout the volume of bone. They consider 

the dose, 0 0 , in a small, tissue-filled cavity in an infinite extent of mineral bone uniformly 

contaminated with the radi~nucllde and give dose factors Ds/00 and Dm/D0 for obtaining 

the absorbed doses. Por both Sr-89 and Sr-90, the ratio of D5/Dm is about 1 • .5. Therefore, 

since the dose limit recommendations are 15 rem to bone and .5 rem to red marrow 

(occupationallimim), the dose to red marrow is the limi ring criterion and will be used in this 

report (26). 

The work of Spiers and his coworkers has been used by the ICRP (27) in calculating dose 

commitment factors for adultS and by Papworth and Vennart (41) for doses as a function of 

age at times of ingestion. The dose commitment values from Papworth and Vennart in red 

marrow per l.ICi of Sr-89 and Sr-90 ingested are as follows (Table 6). 

10 

Table 6. Dose commitment values 

for Sr-89 and Sr-90 

Age at Ingestion (years) 

rem P$1r JJCl ingested8 

r-89 Sr-90 

0 0.414 4.03 

0.5 0.194 2.49 

1 0.130 1.83 

2 0.080 1.20 

3 0.060 0.91 

4 0.050 0.77 

5 0.044 o. 70 

6 0.039 0.69 

7 0.035 0.71 

8 0.032 0.76 

9 0.029 0.83 

10 0.026 0.89 

11 0.02.3 0.94 

Adultsa 0. 012 0. 70 

8Ages o-Li from Papworth and Vermart (41), 

Adults from ICRP-30 Supplement to Part 1 

(27). 

Thus the dose- conversion factors adopted in rem/uCl ingested are for Sr-89, 0.194 and 

0.012, and for Sr-90, 2.49 and 0.70, for the infant and adult, respectively. As before, the 0.5­

year infant is taken as the aitical population. The values for the adult are those given in 

ICRP 30 (27) which also used the work of Spiers and coworkers. . 

2.1.5 Other-Radlonuclldes 

Adult - The:- most authoritative reference· using current data and models for dose 

conversion factors per uCI ingested is that of the ICRP 30 (27) Part 1, 1979; Part 2, 1980; 

Part 3, 1981; and the Supplements, Pergamon Press (42). ICRP 30 Parts 1, 2, and .3 (and 

Supplements) provide data only for adults (occupational workers) for the radionudides of 94 

elements. 

As a ft.rther resource, ORNL/NUREG/TM-190 is suggested (37). This document 

represents initial efforts by ORNL under contract to NRC to provide review and update 

on internal dosimetry. 

Infant, Child - Unfortunately the initial efforts to update internal dosimetry have all 

been directed at the adult or occupational worker and comprehensive dosimetry using current data for the younger age groups do not exist. Further efforts are in process or contemplated by the U.S. Nuclear Regulatory Commission (NRC), Medical Internal Radiation Dose 

Committee, (MJRD), Society of Nuclear Medidne, and NCRP, and generally will involve or 

use the models developed by Oak Ridge National Laboratory (ORNL). Until such time that 

new dosimetric calculations appear for the younger age group, it is suggested that Nuclear 

Regulatory Commission Regulatory Guide 1.109 be used: "Calculation of Annual Doses to 

Man from Routine Releases of Reactor Effluents for the Purpose of Evaluating Compliance 

with 10 CFR Part 50, Appendix I," Regulatory Guide 1.109, Revision 1, Oct. 1977, U.S. 

Nuclear Regulatory Commission, Washington, D.C. 2055.5. · 

11 

2.2 AGRICULTURE TRANSPORT MODELS 

A review of the agricultUral transport mechanism for radionuclides, which employs parameters appropriate for the U.S. experience, is contained in the Reactor Safety Srudy, 

WASH-1400, Appendix VI (7). An analysis specific for calculating derived response levels 

(concentration values) in agricultural media for emergency action that reflects thf British 

experience is found in a report of the Medical Research Council (43). 

A more recent and comprehensive assessment of the transport mechanisms for chu ~oragecow-milk pathway is found in UCRL-51939 and will be used here (41f) 

2.2.1 Transport Models 

According to Ng et al., 'the time dependency of the concentration of a radionuclide in 

the milk of a cow continuously grazing pasare contaminated by a single event can be 

~~~~ . 

n ·AME·t -A. t CM(c) =fc(O) 1: A· e 1 - e p i=l 1 A.p - AMEi 

where CM(t) = concentration of radionuclide in milk ac time t ( 1.1 Ci/1) 

lc(O) =initial rate of ingestion of racfionuclide~ the cow (1JCi/d) 

Ai = coefficient of ith exponential term, which describes the secretion in milk (llter-1) 

AMJ!i: effective ellmination rate of the 1th milk component (d- 1) 

AMEi = AR +AMBi 

AR =radiological decay constant (Q- 1

) 

AMBl =biological ~mination rate of ith milk component (d"' 1

) 

A.p = effective rate of removal of the nuclide from pasture (d- 1), and 

A.p = AR + A.w, where A.w is removal rate for a stable element from pasare (d- 1), 

and 

t = dme of milk secretion (d). 

The total activity ingested by a person who drinks this milk can now be determined by 

integration: 

CD <Ill CD f I dt =f JCM(I:)dt =.{, Jlc(O) 0 0 

where I= race of ingestion of the radionuclide by a person (1JCi/d) and 

J =rate of (X)nsumption of milk (liter/d). 

The solution for the coca! activity ingested by man is: 

Jcol dt =Jlc( O)fM 

0 ).p 

12 

where fM = transfer coefficient; i.e., the fraction of daily intake by cow that is secreted per liter·of milk at equilibrium (d/Uter) 

n A· fM = 1: ---L. 

1=1 AMBi 

Ng et al. have conduc;:ted a comprehensive review of the literature relevant to the determination of transfer coefficients for bpth stable elements and radionuclides (44). These 

data are summarized in UCRL-51939, which also include values-..::~ the norma.tized coefficients, Ai, the biological half-life TMBi (related to ~s > for sr!lected elements and 

values of fM for all stable elements. This information .is then used witl'! the radioactive halflife to calculate values of fM for specific radionuclides of interest (1able B-1 of Ng et al. 

(44)). 

An examination of the logistics of the forage-cow-mllk-man pathway shows that there 1s 

generally a delay time between the production of milk by the cow and its consumption by 

the general public. Therefore, it is appropriate to introduce a factor, S; to account· for 

radioactive decay between production and consumption, where 

S = e -At where A = the decay constant for a given radlonuclide ( d- 1

) 

and t =the delay between production and consumption (d). 

Since the delay time for fresh whole milk is assumed to be 3 days only I-131 of the 

radionuclides of interest here has a sufficiently short half-life to result in a value of S 

significantly smaller than one. Thus, for I-131: 

S(l-131) =e -o.ou x 3 

s(I-131) =o.n2 

Therefore,. the total activity ingested as calculated by the above formula (./tdt) must 6e 

multiplied by 0.772 in the case of iodine-131. 

2.2.2 Total Intake 

The calculated values of integrated activity ingested per lJCl/m 2

. deposition .from 

Appendix B of UCRL-51939 will be accepted as the basis for deriving the response levels 

equivalent to the PAG (44) • The values in Appendix B are based on these values of 

parameters: 

(1) Ic(O), initial rate of· intake by cow 

UAF ="utilized area factor" (93) 

UAF = 45 m ''ld 

Initial Retention on Forage =0.5 fraction 

Initial Deposition = 1 1JCi/m 1 

thus Ic(O) = 22..5 lJCl/d, 

(2) J =1 liter/day consumption of milk, and 

(3) Half-residence time on forage is 14 days. 

13 

The UAF of 4-.5 m 2

/d assumes a forage consumption by the cow of 11.2.5 kg/d dry weight 

or 56 kg/d wet weight based on a forage yield of 0.25 kg/m 2 (dry weight) (45). 

The values of the total intake per unit deposition ( JJCi JJCi m 2) for a 1-liter per day milk intake from Ng et al., are given in Table 7, line 1 (4-4) • 

Table 7. Derivation a:f respor.e IIIYI!is equivalent to 1 rem dole ccmmilnem to critical orpn 

1-m ~s- 1:!5 ~.:.m Sr • ~~~ !r - !9 

1. Pathway lnt.lke factory ( •z> 1.~ 3.12 3.22 .636 .46 

'IJCI/uCI/m1 !!!!!: !.ld) l'iilant ~aiilt rm.,t il:ault 1mant il:aiilt 1mant il:ault lmant fl:iit 

2. 	0c:M CDnversion factor 16 t • .'J .us .061 .07l .061 2.1f9 .70 .1~ .012 

~tE!!l!JCl l!:!eted~ 

.063 .61 &.5 14.7 14.1 16./f .40 1.1f3 ,,2 33 

llnlt 2 

3. lnt.lke I*' r.-n <-'-) ~!&1 l!ttl!!! ll!! r.-n! 

,,.,. If. Specific Intake fac:tor (Una 1 x .no- 2.1& 1.12 z.v 1.77 .3, .m .V3 

Q.7 or o.,} - 'uCl !!!!: u C!lm1 	 ·" 

.0&6 1.17 3.9 &.6 6.3 9.3 .90 16 329 

!UCI/m' !!!!!: r.-n! 

5. lnltlal suiliOit depolitlon <Ui:Jl 	 .., 

6. 	Peak concentration factor (see text) o.uo 0.07& o.on o.OlH 0.011 

{I.ICIJL !!!!!: u Cl/m1 ~ 

7. 	Peak milk c:onc:entratlon .0100 .136 .303 .67 .49 .12 .0171 .oao .211 .5.9 

(llne ' x Jlne 6)

!!&Ill. I!!E r.-n! 

&. lnltllil 

(llne 

rx 0.4) CD!ICefttraticn .on' .117 1., 3.43 2.$0 3.70 .361 1.63 6.40 ~ 

~I.ICI/1:!1 1:5! r.-n) iiCOIT1!1:ted for decay durin& <!Lstribution (3 days fac:tor- .772) 

2.3 DIETARY INTAKE 

Infant less than 1 year ·old - For the purposes of these recommendations, the dietary 

intake of milk is estimated to be 0.7 liters per day for a newborn infant. 

Based on the average intake up to and including 1 year of age, the daily intake of milk 

for an infant less than 1 yei!r of age is 0.7 liters (4~). An additional 300 g of food may also 

be assumed to be ingested by an infant less than 1 year of age (based on intake of 6 monthold infants- Kahn, B. {47)). 

Adult - Basecl on U.S. Department of Agriculture Household Food Consumption Survey 

196.5-1966, the average consumption for the general population is given in Table 8. The 

dietary intake of milk is taken to be 0.55 liters per day for the adult. 

In addition to water ingested in food and drink, an estimated 150 ml of tap water is also 

ingested each day (46) for a total daily food intake of 2.2 kg. 

14 

TableS. Average consumption for the general population 

Average consumption 

Food 

for the ;eneral population g/da % of total diet 

Milk, cream, cheese, ice creama 

Fats, oils 

567.5 

54.5. 

27.2 

2.6 

Flour, cereal 90.8 4.3 

Bakery products 

Meat 

149.8 

217.9 

7.2 

10.4 

Poultry S4.S 2.6 

Fish and shellflsh 22.7 1.1 

Eggs 

Sugar, syrups, honey, molasses, etc. 

S4.S 

72.6 

2.6 

3.S 

Potatoes, sweet potatoes 

Vegetables (excluding potatoes) fresh 

104.4 

14.5.3 

s.o 

7.0 

Vegetables canned, frozen, dried 77.2 3.7 

Vegetables juice (single strength) 9.1 0.4 

Fruit, fresh 163.4 7.8 

Fruit canned, frozen, dried 36.3 1.7 

Fruit juice (single strength) 45.4 2.2 

Other beverages 

(soft drinks, coffee, alcoholic bvgs.) 

Soup and gravies (mostly condensed) 

Nuts and peanut butter 

177.1 

36.3 

9.1 

8.s 

1.7 

Jb!. 

Total 2088.1 99.9 

4 Expressed as calcium equivalent; that is, the quantity of whole fluid 

milk to which dairy products are equivalent in calcium content. 

(From the U.S. Department of Agriculture Household Food Consumption Survey, 196.5-1966) 

2.4 CALCULATIONS 

The calculation of the derived response levels equivalent to i rem dose commitment 

to critical organ for the gra.ss-cow-mllk-man pathway is summarized in Table 7. An explanation of Table 7 and the calculations follow: 

Line 1 Pathway Intake Factor is the total intake (l.aCi) for a 1 liter per day milk 

ingestion per 1 1JCi/m2 of initial area deposition (44). · 

Line 2 Dose Conversion Factor is the dose commitment in rem/lJCi ingested. See 

section ·1 for summary. 

Line 3 Intake per rem is intake in 1J Ci to yield a 1 rem organ dose. 

COMPUTATION - The reciprocal of line 2. 

Line 4 Specific Intake Factor is the product of the Pathway Intake Factors (line 1) and 

the milk ingestion rate of 0.1 1/day infant or O.SS 1/day adult. In the case of I-131, a 

factor of 0.772 is included to adjust for 3 day's decay between production and consumption. 

COMPUTATION- Line 1 x (1 or .772) x (0.7 or O.SS) 

· Line S Initial Surface Deposition is initial area deposition of a specific radionuclide in 

1.1Ci/m2 which gives a 1-rem dose <:ommitment. 

15 

COMPUTATION - Line 3 divided by Line ~ 

' Line 6 Peak Concentration Factor is the ~ak maximum concentration in milk ( JJCl/1) 

from an 1nitial area deposition of 1 JJCi/m • Summary in Section 2.2.3 per model of 

Ng et al. (44). · 

Line 7 Peak Milk Concentration is the maximum milk concentration ( JJCl/1) that yields 

a dose commitment of 1 rem from continuous ingestion of the contaminated milk supply. 

COMPUTATION- Line 5 x Line 6 

Line 8 Initi.al Grass Concentration is the activity concentration ( \.lCi/kg) on grass 

(edible forage) that results from the Initial Surface Deposition giving a 1-rem dose 

commitment. 

Retention fraction on forage - 0.5 

Forage yield- 1.25 kg/m 2 (wet weight) 

COMPUTATION - Line 5 x 0.5 

1.25 kgm 2 

The derived response levels that correspond r::o the Preventive PAG (1.5 rem thyroid: 0.5 

rem whole body and bone marrow) and· the Emergency PAG (15 rem i.ilyroid; 5 rem whole 

body and bone marrow) are given in Tables 9 and 10. 

Table 9. Derived response levels for grass-cow-milk pathway equivalent 

to Preventive PAG dose commitment of 1.5 rem thyroid, 0.5 whole body 

or red bone marrow to lnfant 1 

Response levels for 

Preventive PAG I-131 2 Cs-1343 Cs-137 1 Sr-90 Sr-89 

Initial activity 

area de~i tion 

( lJC1/m2 ) 0.13 2 3 0.5 8 

Forage concentration• 

( lJCl/kg) 0.05 0.8 1.3 0.18 3 

Peak milk acitivil:y 

(\.lCl/1) 0.015 0.1.5 0.24 0.009 0.14 

Total intake ( uCl) 0.09 4 7 0.2 2.6 

1Newbom infant includes fetus (pregnant women) as critical segment of population 

for locllne-131. For other radionuclldes, "infant" refers to child less than 1 year of 

age.

2From fallout, iodine-131 is the only radioiodine of significance with respect to milk 

contamination beyond the first day. In case of a reactor accident, the cumulative 

intake of iodine-133 via milk is about 2 percent of iodine-131, assuming equivalent 

deposition.

3Intake of cesium via the meat-man pathway for adult may exceed that of the milk 

pathway; therefore, such levels in milk should cause sll'velllance and protective actions for meat, as appropriate. If both Cs-134 and Cs-137 are equally present, as 

might be expected in reactor accidents, the response levels should be reduced by a 

factor of 2. 

&tFresh weight. 

16 

Table 10. Derived response levels for grass-cow-milk pathway equ.vaJent to emergency PAG dose com~itment 

of U rem thyroid, ' rem w~1e body or red bone marrow 

Response levels for 1- 131' Cs- 1341 Cs- 1371 Sr- 90 sr·- 89 

emergencl PAG lnfant 1 Adult lnfant 2 Adult lnfant 2 Adult lnfant 2 Adult lnfant 2 Adult 

lniticil activity 

area deposition 

haCi/m2 ) l. 3 18 20 lfO 30 jQ 20 so· 1600 ' Forage concentration 

( pCi/kg)" O.j 7 8 ·J7 13 19 1.8 8 30 700 

-....... Peak milk activity 

( pCi/t) o.u 2 J.j 3 2•• If 0.09 O.lf l.lf 30 

Total intake ( J.1 Ci) ·· 0.9 10 lfO 70 70 80 2 7 26 lfOO 


1Newborn infant includes fetus (pregnant women) as critical segment of population for l~ne-131. 211 Infant" refers to child less than I year of age. 
 1From fallout, iodlne-lllls the only radioiodine of signlfi~oce with respect to milk contamination beyond first day. In case 


of a reactor accident, the cumulative intake of iodine-Ill via milk is about 2 percent of iodine-131 assuming equivalent deposition. . 


•Fresh weight. 5 1ntake of cesium via the meat-man pathway for adult may ex~eed that of the milk pathwaya therefore, such levels ln milk 

should cause survelllance and protective actions for meat, as appropriate. If both Cs-lllf and Cs-137 are equally present as 

might be expected for reactor accidents, the response levels should be reduced by afactor of 2. 
CHAPTE.R 3. METHODS OF ANALYSES FOR RAOIONUCLIDE DETERMINATION 

3.1 JNTRODUCTION 

The measurement of radionuclides in food can be accomplished by either laboratory 

methods or field methods using portable survey instrumentation. Unfortunately, neither 

method of analysis was developed expressly for the purpose of implementing protective 

actions. In order to provide instrumentation guidance to the States, the Federal Radiological Preparedness Coordinating Committee formed a Task Force on offsite instrumentation. 

A draft report on instrumentation analysis methods for the milk pathway is now undergoing 

review by the Task Force and a second report on other food is under development. This 

effort is being' fostered by past and current contracts of Nuclear Regulatory Commission 

(NRC) and Federal Emergency Management Agency (FEMA) with Brookhaven National Laboratory and Idaho National Engineering Laboratory. 

The material and methods are given as interim guidance until these more definitive 

reports are available. It should be noted chat laboratory methods of Chapter 3.2, below, 

were developed for environmental monitoring purposes and are more sensitive than required 

for protective actions implementation. And, conversely, the field methods of Chapter 3.3 

are generally inadequate for the purpose of implementing action at the Preventive PAG 

level. Analysis methods should be able to measure radionuclide concentrations in food lower 

by a factor of 10 than the derived levels for Preventive PAG. Thus, it may be necessary co 

use a combination of laboratory and field methods in implementing and ceasing protective 

actions. 

3.2 	 DETERMINAnoNS OP RADIONUCLIDE CONCENTRA nONS BY SENSITIVE 

LABORATORY METHODS 

Many compendia of· methods of analysis of environmental samples are available. The 

EML Procedure Manual recommended is noted for its UP-to--date methodologies,· which 

continuously undergo revision and improvement (48). Analysis need not be limited to reference l.f.8 but laboratory analysis of food should provide limits of detection as listed below, 

which are lower than required for protective action: 

Limit of detection* 

Radionuclide pCi/liter or kg' 

I-131 10 

Cs-137 10 

Sr-90 1 

Sr-89 5 

*Concentration detectable at the 9.5-percent confidence level. 

A source of more rapid methods of analysis of radionuclides in milk, applicable to these 

recommendations is described by B. Kahn et al. (49). The methods for gamma radionuclide 

analysis (applicable to I-131 and Cs-137 presented in this reference are also applicable to 

pasture. The gamma scan determinations of 1-131 and Cs-137 in milk (or wacer) can 

generally be accomplished within 2 or 3 hours. For samples measuring in the 0-100 pCi/licer 

range, the error at the 9.5-percent confidence level (2 sigma) is .5 to 10 pCi/liter. For 

samples measuring greater than 100 pCl/liter the error is 5 to 10 percent. 

18 

R~ostrontium procedures permit analyses of several samples simultaneoUsly in .5 hours 

of laboratory bench time, plus 1-2 weeks for ingrowth of yttrium daughters. If the laboratory is set up for routine analysis of these radionuclides recovery in tracer studies is 80 ± .5 

percent. 

An ion exchange field method for determination of I-131 in milk, whidj uses gamma 

spectroscopy after. sample collection, has also been desaibed (.50). The main advantage of 

this method is that it permits a large number of samples to be processed in the field or 

shipped and analyzed in a central laboratory•. 

· For analysis of sampl~ other than milk the HASL reference (48) is recomrr ended. 

3.3 DI!TERMINAnONS OF RADIONUCLmE CONCI!NTRA TIONS BY FJELD METHODS 

3.3.1 Ground Contamination {Beta Radiation) 

The conversion of ground sw-vey readings to contamination levels can be accomplished 

by usl~ the following equations and factors (assuming a metal rube wall thickness (steel) of 

30 mg/cm1): 

1. Use a G-M 5\l'vey meter callbrated to yield 3,000 counts/min per 1 mR/h of Ray. 

2. Hald the probe·not more. than 'em above- the ground with the beta.shield open. 

3. Assure that 100.counts/min can be detected above a ..normal.50 to 100 counts/min· 

background. 

4. Take readings in open terrain; that is,. not in close proximity to heavy vegetation, 

cover, or buildings. 

For determinations· of ground deposition: 

0 =R x.P 

. where, 0 = ground deposition (in 1J Cl/m1 ), 

R = G-M reading (in units of 101 counts/min) (backgroll'ld 

corrected) , and 

P = factor given in Table 11. 


For determination of concentrations in vegetation: 


c =(D X f) d 


where, C =concentration (in 1J Cl/kg), 


0: ground deposition (in 1J Ci/m1 ), 


f =fraction of deposited nuc!ide in the vegetation, and 


d =density of vegetation cover (in kg/m1 ). 


Generally, f ranges from 0.1 to 1 and is usually taken to be 0.2.5 for 1-131 in the 

United Kingdom, and 0 • .5 in the United States. 

19 

Data of a similar nature may also be found in "Emergency Radiological Plans and Procedures," in the Chapter (Item 04.3.4) on "Conversion of Survey Meters to Concentration," (.51). 

Table 11. Ground surface contamination levelsa of various nuclides 

required to yield 100 counts/min (net) on a G-M meter (open window) 

F 

Nuclide (u Ci/m2 per 100 counts/min) 

Zr-9.5 + Nb-9.5 6 

Ce-111-1 2 

I-1.31, Ru-10.3m, mixed Ru-Rh (100-d old)b 1 

Co--60, Sr-89,. Y-90, Y-91, Cs-1.37, Ba-140, La-140 . ~ Ce-144 + Pr-144, Ru-10.5 + Rh-106, 0 • .3 

mixed radioiocllnes ( 1-h to 1-week old), 

mixed fission-products ( 100-d old) 

aLeve! varies with background readings, ground roughn~s, and vegetation cover. bAge refers to time since irradiation of the fuel from which the Fission Products were 

released. 

3 • .3.2 Herbage 

A field method for estimation of radionuclide contamination at the response levels 

equivalent to the Emergency PAG for pasture (forage) which has been suggested by 

International Atomic Energy Agency (52) is as follows: 

1. Obtain enough vegetation to fill a 30 em x 40 em plastic bag approximately half 

full. This is about one-third of a kilogram (Note: the vegetation cover should be obtained 

from at least 1 m2 of groi.Jnd. The vegetation should be cut at approximately 1 to 2 em 

from the ground and should not be contaminated in r:he process by soil). 

2. 	Note the area represented by this quanti ry of material. 

3. Compress the air from the bag and seal. 

4. Transfer the sample to a low background area. 


.5. Flatten bag and lay probe of a portable G-M survey meter on the center of the bag. 


6. 	Wrap bag around probe and note reading (window open and background corrected). 


7. 	Calculate the contamination from the following equation: 

C= R/k 

where,· C =vegetation concentration (in 1J Ci/kg), 

R = G-M reading (in units of 10: counts/min) (background corrected), and 

k = 102 counts/min per 1J Ci/kg as given in Table 12. 

8. 	Convert 1J Ci/kg to 1J Ci/m2 on the basis of the area represented by the sample. 

20 

· 9. 	 The limiting radionudide (i.e., having the lowest recommended PAG relative to 

its deposition on pasture) is lodine-131. According to Table 12, this radionudide 

is detected with the lowest efficiency. Thus, if the operator assumes this 

radionuclide to be exclusively present in the pasture the most conservative 

estimates relative to the Emergency PAG would be reached. 

Table 12. Typical G-M survey-meter readings probe 

inserted in the center of a large 

sample t. f vegetation · 

Nuclide (10' x counts/min per llCi/kg) 

Sr-89, Sr-90 + Y-90 20 · Ru-106 + Rh-106 50 

Ba-140 + La... l40 10 

I-131 Cs-137 If. 

3.3•.3 MUk 

The experimental data for field determination of radionuclides in milk are limited to 

determination of iodine-131, and the details are rather sketchy. What material is available 

is abstracted below. 

·1. Although no data are available for field determination of radionuclldes other th.an 

!odine-131 in milk, Table .13 presents experimental information obtained in water {,2,,3)•. 

To the extent milk is more self-shielding than water, the following data is presented as a 

guide rather than a means of analysis. · 

Table 13. G-M survey-meter open window readings (counts/min 

per JJCi/llter) (probe immersed in contaminated water) 

size of sample contamer 

Nuclide I liter 5 hters 

Counts/min per 

> Io liters 

JJCili 

Sr-89 

Sr-90 + Y-90 

Ru-106 + Rh-10' 

I-131 

Cs-137 

Ba-140 + La-140 

2000 

2000 

6000 

500 

400 

1000 

2000 

2000 

8000 

800 

600 

1.500 

2000 

2000. 

10000 

1000 

800 

2000 

2. Method of Kearney (.5lf.): 

a. Instrument: CDV-700 Model No. 68 with beta window closed at all times. 

b. Geometry: See Figure 1. 

c. 	 The count rate is determined gy ear. If the counts per minute recorded gy 

ear are more than 60 to 70 cpm, then the milk should be diluted with "pure" 

water so as to produce a sample having a 5096-.5096, 2596-7.596 or other 

concentration low enough to produce counts per minute somewhat less than 

60 to 70 cpm. 

d. 	 Background: The experimental conditions duplicated "sky shine" from a transPacific transfer of fallout. If the exposure around the test hole was 0.75 

mR/hr a couple of feet above the hole, the sky shine increased cpm recorded 

21 

by the probe shielded within the test hole by 3 cpm. Background, on the average, was measured (in "pure" water) to be 12 to 15 cpm (in an uncontaminated 

environment). Thus, total background counts (with sky shine) is on the average 

arot.Ktd 19 cpm. 

e. 	From Figure ,2, the net counts per minu~e equivalent to the response level for 

the Emergency PAG applicable for milk (infant as critical segment of 

population) is approximately 20. , 

3. 	Method of C. D.istenfeld and J. Klemish (,.5). 

a. 	Instruments: 

i. 	 CDV 700 instrument turned to 10 X scale and calibration aqjustment turned 

to require the meter to indicate 2 mR/hr. (NB: Disa'epencies were noted 

between data from scale and pulse counting with an oscilloscope). . 

li. 	Modified CDV 700 M with factory calibration. Good agreement between 

scale reading and electronic check. 

b. 	Geometry: The basic container was a '-gallon heavy-wall polyethylene "Jerri" 

type meastring 12x9x10 inches. A 2-inch O.D. blind tube was installed to 

allow the G.-M probe to sample the center of the container. 

c. 	Col.mts were.· taken inside- and at the top-(external) to the container. 

d. 	Background was determined in a water filled plastic container (l.Sx2.5x20 em) 

about 7 meters from the sample vessel. 

e. 	Net comts per minute equivalent to the response levels for the Emergency 

PAG for· milk are·smnmarized in Table 14. 

4. 	 The International Atomic Energy Agency reports on a series of experiments ('3). 

The data are duplicated in Table 15•. 

'· 	A forthcoming ~report .·of the Federal Interagency Task Force on Offsite 

Emergency Instrumentation for Nuclear Incidents to be published by FEMA is 

"Monitoring and Meastrements of Radionuclides to Determine Dose Commitment: 

in the Milk Pathway." A subsequent report by the Task Force will address field 

methods and monitoring strategies for other food pathways. 

6. 	The re!ative sensitivit;y of the various techniques is summarized in Table 16. 

22 

·Water tl;ht 

AI or plastic tube P1oatlc nning (1 .. to 1 1/2.. 


dlam.; 3' lon;) 


Figure 1. Geometry for making 

measll'ements within a volume 

of liquid. 

*<:DV-700, Model No. 68 cover-.:1 with smoll pfaaffc bag taped. to cable 

of probe to further protect against dom"n"•· 

(After Kearny ORNL-4900) 

•

-..

E 

0 

""'!­ "' 

-

C'll

-

-

~ ~ ~ ~ 1~ 1~ 1~ 1~1- ~~~ 

Net Counts Per Minute• 

~et counts per minute daterrniaed by ear. Net countS: per 

minute =grosscounts per minute - badcground In p~re watllf'. 

Figure 2. Net counts per minute* 

23 

Table 1/J. Net counts per minute equivalent to the response levels for the Emergency PAG for milk . · · 

Approximate . net counts per minute 

Instrument CDV-700 CDV-700M 

Probe Position Inside OUtside Inside · Outside 

Response level for 

Emergency PAG . 

(Milk-Infant) aa ' 220. 100 

(Milk-Adult) 260 110 2, 900 1, 300 

aAt or below. background cpm- precision not adequate. 

Table 15. Survey-meter readings versus concentration 

of 1-131 in a LJO-llter milk can 

l!Ci I-1311Uter Net counts per minute 

milk Inside can Outside can 

At-walled 0.9 1,.500 300 

GM probe o.s .500 200 

0.1 100 so 

0.'0.5 .50 .50 

Background .50 .50 

Mica-window 0.9 600 2.50 

GM probe o.s IJOO 100 

0.1 100 .50 

0.0, .50 .50 

Background .50 .50 

a,a,y 0.9 ,,,oo 3,000 

scintillation o.s 3,000 1,.500 

survey-meter4 0.1 600 300 

o.os 2.50 1.50 

Background 100 100 

Transportable 0.10 1,200 

single-channel o.os 6,0 

analyzer system 0.01 140 

0.00.5 80 

Background 30 

acrystal is 3-mm thick disc of "Bioplastic." scintillator sprayed with 1 10 mg/cm1 of ZnS. Effective area is 6.4 c.m • 

24 

Table 16. Comparison of methodologies 

cpm per 1J Ci liter-1 

Inside Outside 

IAEA 1974 ('2)

Kearney - ORNL ( ,.) 

1,000 

140 

·DJstenfeld and Klemish - Brookhaven ('')

CDV-700 

CDV-700M 

134 

1,4,0 '6 

660 

IAEA - 1966 U3). 

A1 Walled GM Probe 

Mlca-Wlndow·GM Probe 

1,100 

700 

3,0 

2,0 

Ch 8•Y Sc:intillatlon 6,000 3,3~0 

SurVey Meter 

Transportable Single 

Channel AnaJxser 12,000 

­

2' 

CHAPTER 4-. PROTECTIVE ACTIONS 


The National Advisory Committee on Radiation (.56) (NACOR) made the following recommendation that applies to action taken to reduce potential exposure following the accidental 

release of radioactivity: 

"A countermeasure, useful to public health, must fulfill a number of 1·~qniremesu~ 

First, it must be efiective; that is, it must substantially reduce population exposures below 

those which would prevail if the counter measure were not used. Second, it must be safe; 

i.e., the health risks associated with its use must be considerably less than those of"Ciie 

contaminant at the level at which the countermeasure is applied. Third, it must bepractical. The logistics of its application must be well worked· out; its costs must bereasonable; and all legal problems associated with il:s use must be resolved. Next, 

responsibility and authority for its application must be well identified. There must be no 

indecision due to jurisdictional and misunderstandings between health and other agencies 

concerned with t•adiation ¢ontrol. Finally, careful attention must be given to such 

additional considerations as its impact on the public, industry, agriculturet, and government." 

An action, in order to be useful must be effective, safe, and practical. An action may- be.: 

applied at the source in an attempt to control the release of radioactivity from the source; 

or, the action may be applied at the beginning of met food chain (soil, vegetation, or cattle),. 

to the immediate vector prior to ingestion by man (milk or food), or to the population itself. 

For the most part these recommendations suggest protective actions to milk, human and 

animal foods, or soil and this chapter· is limited to actions concerning these media. Further 

recommendations by NACOR (.56) extend the discussion of protective measures to public 

health actions directly affecting the exposed population. For details of agriculture actions, 

several Department of Agriculture reports are available that deal with specific actions for 

crops and soil (.57,.58,.59). 

Potential actions relative to the pasture-milk-man pathway are swnmarized in Table 17. 

For this pathway, only four countermeasures are rated as effective, safe, and practical (a 

somewhat arbitrary scale of judgment was used). Of the four, one has distinctive 

disadvantages. Although removal of radionuclides from milk has been shown to be practical 

no facilities for doing this exist. Another, diverting fresh milk to processed milk products, 

freezing and/or storage, is effective only for short-lived radionuclides. Thus, changing 

dairy cattle to an alternate source of uncontaminated feed and condemnation of milk 

are the only two protective actions rated good for effectiven~s, safety, and practicality. 

Of course the other countermeasures should also be considered, but they appear less 

promising. 

Actions for fruits and vegetables are presented in Table 18 (60,61,62).. Note that studies 

in which these products were contaminated under actual conditions with fallout (Studies 

2 and 3) yielded a lower reduction in the radioactivity removed during preparation than 

was the case in an investigation (Study 1) in which radionuclides were sprayed on the food. 

Depending on the food, reduations between 20 and 60 percent in strontium-90 contaminations 

are possible by ordinary home preparation or by food canning processes (60). 

Milled grains contain only a small portion of the total radioactive contamination of 

the whole grain; removal of bran from wheat and polishing of rice are effective methods of 

reducing contaminating fallout (.58). Todd indicated average concentration of Sr-90 (pCi/kg) 

26 

in wheat of wheat berry (2296), wheat bran (6896), and only lf..l+96 in flour. In rice the corresponding values are: whole grain (lf..996), and milled rice {0.796) (.58). 

Although these recommendations are intended for implementation within hours or days 

after an emergency, long-term actions applicable to soil are shown for i~ormation purposes 

only in Table 19. Alternatives to decontamination and soil management should be 

considered, especially if the radioactive material ~ widespread, because great effort is 

required for effective treatment of contaminated land. 

' The concept of Protective Action asswnes that the actions inipien ented will continue 

for a sufficient period of time to avoid most of the projected dose. T.'le concentration of 

radioactivity in a given food will decrease because of radioactive decay arid weathering as a 

function of time after the incident. Thus, as discussed in Chapter 5 ot this report, actions 

that have a positive cost-benefit ratio at the time of initial contamination or maximum 

concentration may not have a positive cost-benefit ratio at later times. Therefore, dependent on the particular food and food pathway, it may be appropriate to implement a series of 

protective actions until the concentrations in the food have essentially reached background 

leve.ls. 

As an example of the implementation of protective actions, consider the case where an 

incident contaminates the pasture-cow-milk-man pathway with a projected dose of 2-3 

times the Emergency PAG due to iodine-131. In such a situation these protective actions 

may be considered appropriate: 

1. Immediately remove cows from pasture and place them on stored feed in order to 

prevent as much lodine-131 as is possible from entering the milk; 

2. Condemn any milk that exceeds the Emergency PAG response at the farm or milk 

plant receiving.station; 

3. Divert milk contaminat~ at levels below the Emergency PAG to milk products; 

and 

1+. Since the supply of stored feed may be limited and the costs of this protective 

action greater than diversion to milk products, the use of stored feed may be the firs't 

action to cease; this should not be done, however, until the concentration of I-131 has 

dropped below the Emergency PAG and preferably is approaching the Preventive PAG. 

5. The diversion of fresh milk to milk products must continue until most of the . projected dose has been avoided; this action might be ceased when the cost-effectiveness 

point is reached or the concentration of iodine-131 approaches the background levels. 

This discussion assumes that there is an adequate supply of whole milk from noncontaminated sources, that there is an available manufacturing capacity to handle the diverted 

milk, and that the iodine-131 is the only radionuclide involved. 1n an actual situation these 

conditions may not be· present and other factors may affect the practicality of proposed 

protective actions. The agency responsible for emergency action must identify and evaluate 

those factors that affect the practicality of protective action, and thus develop a response 

pian (with tentative. protective action) that is responsive to local conditions and capabilities. 

27 

Table 17. Actions applicable to the pastll"e-mllk-man pathway (complied from references 57 and 59) 

RadtonUcllde(s) for which protective action Is applicable 

Practicality 

Action Effectiveness Safety (effort required) 

Applicable to cattle 


Provide alternate soUice of 


1111 11 117 uncontaminated animal feed , ..s r, s r, cs (+)a (+) (+) Good 

.... Add stable loc:ftne to cattle ration Marginalb Some hazard (+) 

Add stable caldwn to- cattle ration 11Sr, ••sr Marginal Some haiard (+) 

Add binders to cattle ration 111Cs, 11Sr, ..Sr Marginal Questionable (+) 

117c 11 Substitute sources of uncontaminated water s, s r, ..s r (+) (+) (+)C 

Applicable to milk 

1111 11 117c N Condemnation of milk , s r, ..sr, 1 (+) (+) (+)d Good 

00 

Divert fresh milk to processed mUk products 1111, 11Sr (+) (+) (..) Good 

Process fresh - store ttsr, 111Sr Mar sinaL Questionable (+) 

Process fresh - store llll (+) (+) (+) Good 

1111 11S 11C Remove . (+'e . radionuclidcs from milk , r, ..s r, s (+) (+) , .. 

8 ( +) : 90l6 effective 


bMarginal' less than 90l6 effective 
 ~Depends on availability ·· 
 Somewhat dependent on volume 


eNo processing plant presently available 

Table 18. Percent reduction in radioactive contamination offr~ts and vegetables by processing 

Study i lQ)) . . Normal foOd preparatlon.for freezing, cannin& or dehydration Study 2 (61) Study 3 (62) 

External Contaminationa Internal . Contaminationa cari'Jns Home P/fparation 11Sr 117Cs 10Sr 117Cs Sr 	 Sr 

Spinach 92 88 


Snap. beans 


Carrots 


Tomatoes· 


Broccoli 9/f 92 '72 89 
 '' 

Peaches 	 "' 100 .... aoo ~AlOO .. ·..,.100 jQ

~ Onions 37 

Potatoes 2/f 

Cabbage }j 

Green beans - - - 36 

'Contamination on surface is referred to as external contamination. Internal contamination is cOntamination of fleshy portion of product from surface deposition of radionuclide. · 
Table J9. Actions applicable to soil (compiled from references 57 and 59) 

Ridionucllde(s) for Which protective action is applicable 

Practicality 

Action EffectlyenessB Safety (effort required)~ 

Appllcable to soil 

SoU management-minimum tillage: 

deep plowing with root inhibition 

Poor to fair 

Good to fair 

Not applicable II 

Good 

Poor 

irrigation & leaching Poor II Good 

liming & fer dlizing Poor to fair II Good 

Removing II contaminated surface crops sasr Most.poor Poor to fair 

Removal of soil surface contamination: 

warm weather with ve&etation cover "Sr Good to fair .. Poor 

cold weather no cover "Sr Good to poor II Good to poor 

aaating for reducing strontium -90 

Good - 9>CJ6 reduction 

Fair- 7S-95CJ6 reduction 

Poor - 7 5CJ6 reduction 

bRating for effort required 

Good - not significantly more than normal field practice 

Fair - extra equipment or labor required 

Poor - very great requirement of equipment, materials, and labor 
l' 

CHAPTER 5. COST CONSIOERA TIONS · 


5.1 COST/BENEFrr ANALYSJS 

,.1.1 Introduction 

The general expectation is that protective action taken in . the" event of a nuclear 

incident will result in a net societal benefit considering the cost of the action and the 

corresponding avoided dose. These cost assessments, including cost/benefit analysis, have 

not been used to set the numerical value of the PAG's but rather to evaluate the feasibility 

of specific protective actions. 

Ar: least two basically different approaches can be used to assess me cost/benefit ratio 

of protective actions for the milk pathway. One approach would be to assume a protective 

action scenario (maximum milk concentration and length of time of protective action) and 

to calculate the total cost of the action and the benefit because of the avoided dose. The 

ratio of the cost/benefit can then be used to scale the maximum milk concentration to that 

concentration that· yields equal costs and benefits. The problem with ~his approach is that 

positive net benefits when milk concentration of radioactivity is high .are used to offset 

the negative net benefits during the later times of action. 

This deficiency leads to the second approach of calculating the r:nilk concentration on a 

per liter basis where the cost of the prc;~tective action equals the benefit because of the 

dose avoided. This approach will be used here ·since it gives a clearer picture of the 

identified costs and benefitS. The specific concentration at which costS equals benefitS 

should not however be viewed as the appropriate level for taking protecti~ action. The 

philosophy of protective action is to take action to avoid most of the projected doses. 

Further, the simple analysis considered here treats only the direct cost of protective 

actions and ignores the administrative costs of starting, monitoring, and ceasing action, 

and other related soda! and economic impacts. 

Although the PAG recommendations provide that protective actions be taken on the 

basis of projected dose to the infant, cost/benefit analysis must consider. the cost impact 

on the milk supply and the benefit on a whole population basis. Accordingly the benefit 

realized from avoiding the dose associated with a given level of milk contamination 

C ( '1.1 Cl/1) must be summed over the age groups having different Intakes (I) and Dose 

Factors (OF) and is: · 

Benefit= C (1JC1/1) x Value ($/rem) l:ll(l/d).OPi(rem/l.lCi). 

The total cost of the protective actions, which must also be summed over all the age intake 

groups is: 

Cost = PA COST x 1:11 

Costs are in 1980- 1981 dollars. These equations can then be solved for the concentration 

(C) at which cost= benefit giving: 

C (C=B) = PA COST Ell Value ($/rem) E<n •DFi) 

31 

5.1.2 Benefit of Avoided Dose 

In situations ln which· there has been an uncontrolled release of radioactivity to the 

environmem:, both the health savings and cost of a protective action can be expressed in 

terms of cbllar values. This does nor: exclude the probability that undesirable features will 

result from an action th:t.t is difficult to evaluate in economic terms. 

A previous cost-benefit analysis described the radioactive concentration of iodine-131 in 

milk at which it ~ould '1e justifiable to initiate condemnation of milk (63). Following is a 

summary of the moneta-y benefit of radiation dose avoided using the approach suggested, 

with changes because of increased costs over time and new data on the relative incidence of 

various tumors. 

The International Commission on Radiological Protection, {64) has endorsed the principle 

of expressing the detriment from radiation in monetary terms ln order to facilitate 

simplified analysis of costs and benefits. This permits a direct comparison between the 

societal advantage gained in a reduction of the radiation dose and the cost of achieving this 

reduction. Cost-benefit analysis is the evaluation process by which one can determine the 

level at which, or above which, it would be justifiable to initiate the protective action 

because the health savings equaled or exceeded, the economic costs of the protective 

action. Certain factors, such as loss of public confidence in a food supply, are not 

considered; nor are economic factors because of hoarding and a shortage of supply 

considered. A similar .treatment of the problem with almost the same result has 

been published (65). This type of exercise is useful prior co taking an action as one, and 

only one, of a series of inputs into decisionmaking. 

The costs, and hence health savings to society, of 1 person-rem of whole-body dose (the 

product of a dose of 1 rem to the whole body and 1 person) has been estimated· by various 

authors co be between $10 and $250 (66). The Nuclear Regulatory Commission (NRC) value. 

for a cost-benefit analysis for augmented equipment for Ugtu-water. reactors to reduce 

population dose, sets radiatio11 costs at $1000 per person-rem (67). 

Based on medical expenses in 1970, the total future cost of the· consequences of all 

genetic damage of 1 person-rem {whole-body) was estimated by the BEIR Committee (2) to 

be between $12 and $120. These costs are in good agreement with estimates made by 

Arthur 0. Little, Inc., for the Environmental Protection Agency, which calculated that 

in terms of 1973 dollars, 1 person-rem of radiation yielded a tangible cost of between $.5 and 

$181 due to excess genetic disorders. A tangible cost of between $7 and $24 per person-rem 

was estimated to be the result of excess cancer in the same report. Therefore, the. total 

health cost of a person-rem from these studies is between $12 and $20.5 (68). 

Assuming that $200 ls a reasonable estimate for the overall somatic health cost to society per person-rem whole body, the proportionate cost for individual organ doses must then 

be derived. For the purposes of assessing health cost, it is appropriate to use the relative 

incidence of cancer estimated to result from organ doses vs. whole body doses. From BEIR111 (3) (Table V-1lf.. and V-17, and using an average of the male and female incidence) the 

thyroid contributes 20 percent of cancer and leukemia (red bone marrow doses) 11 percent 

of the total cancer incidence. Hence, the monetary coscs per rem of radiation dose avoided 

are: to thyroid $110; and to red bone marrow $22 • 

.5.1.3 Protective Action Costs 

The direct cost of protective action will be assessed for (1) cost of stored feed, (2) 

condemnation at the farm (farm value), and (3) condemnation at the processing plant (retail 

value). 

1. Cost of stored feed. For the participating herds (May 1, 1978- April 30, 1979) 

the Dairy Herd Improvement Letter (69) reports a consumption of 12,600 lbs. of succulent 

32 

forage and 3,000 lbs. of dry forage, with a corresponding annual milk production of llf.,l29 

lbs. (6200 liter.s). (The cows also conswned 5,800 lbs. of concentrates, which are not of 

concern here.) Taking 3 lbs. of succulent forage (silage) as equivalent to llb. of hay, the 

annual hay equivalent conswnption is 7,201) lbs (70). Thus, 1.16 lbs.. of hay equivalent is 

constmed per liter of milk production. The 1980 average price received by farmers for all 

baled hay was $67.10 per ton or $0.0335 p~r lb. (71). The Protective Action (PA) cost of 

buying baled hay to replace pasture as the sole forage source is then $0.039 per liter. 

2. Milk-farm value. The average pt·ce received by fanners for fluid-ell~le milk, 

sold to plants and dealers in 1980, was· $13."!1 per hundred weight (monthly range $12.70 to 

$14.20) (71). The lower prices are recehed during the pasture season of April through 

August. For 44liters per hundred weight, the farmer value of milk is $0.30 per liter. 

3. Milk-retail value. Since it may be necessary to take protective action at some 

stage in the milk processing and dlstribution system it is appropriate to consider the retail 

value of milk. If condemnation of milk is taken at the receiving station or processing plant 

there will be additional costs above farm value associated with disposal. It is felt that 

retail price should represent an appropriate value. The average city retail price of fortified 

fresh whole milk sold in stores, January through October 1980 was $1.037 per 1/2 gallon 

(72). The monthly price increased from $1.015 in January to $1.067 in October, apparently 

because of inflation. Based on the average price the value of $0.56 per liter will be used. 

5.1.4 Population Milk Intake and Dose 

Table 20 swnmarizes the milk intake by population age groups and gives. values of the 

age group intake factor li{l/d). The total intake by a population of 1000 is 281 1/d or an 

average individual daily intake of 0.28 1. The intake factor (ll) is used with the dose factor 

DFi listed in Table 21 to calculate the dose factor summed over the whole population 

weighted by age per lJCi/1 of milk contamination. 

5.1.5 Mill< Concentration For Cost= Benefit 

The above results are then used to calcultate the milk concentration at which the 

Protective Action (PA) costs equals the benefit from the dose avoided. The results are 

presented in Table 22. The cost =benefit concentration for use of stored feed in place of 

contaminated pasture is about 0.2 to 0.3 of the Preventive PAG for strontium and 0.01 to · 0.02 for iodine and cesitm. For condemnation, the cost= benefit concentrations based on 

farm value of milk have ratios of the Emergency PAG similar to those above. The cost= 

benefit concentrations based on retail value of milk are about a factor of 2 greater than 

those based on the milk's farm value. The fact that the cost = benefit concentrations are a 

significant percent of the PAG for strontitm results largely because the value of the personrem dose to red bone marrow is one-ninth that of whole-body doses while the PAG's are set 

at equal doses consistent with current regulations. Further the controlling PAG's are for 

the infant, while the cost/benefit reflects population averaged benefits. 

Table 20. Population milk intake It 1i) 

Persons per Intake ( fi) by 

1000 popu- Milk intakea age group 

Age group lation (1/d) (1/d) 

In utero 11 .{f. 4.lf. 

0 < 1 1lf. .775 10.9 

1 - 10 146 .lf.70 68.6 

11 - 20 196 .360 70.6 

>20 633 .200 126.7 

Ell 281.2 

aiCRP, 1974 

33 

Table 21. Population dose factors 

Sr-89 Sr-90 

Ii X DFi li x OFl 

DFi !!ID •1 DFi !!m •1 Reference for 

Age group rem/uCi uCi d rem/ HCi HCi d DFi valuesa 

In utero .414 1.82 4.0.3 17.7 0 yr old 

0 < 1 .194 

1 - 10 .0.56.5 

11 - 20 .017.5 

2.12 

.3.88 

1.24 

2.49 

.929 

.82 

27.2 

6.3.8 

57.9 

0 • .5 · yr-old 

Average 

Av 11 yr &: adult 

>20 .012 1 • .52 .70 88.7 Adult 

?;IiDFi 10•.58 2.5.5 •.3 

a:see Chapter 2. 

Cs-1.34 Cs-137 

nx DFi lixDFi 

DFi rem • 1 DFi rem • 1 Reference for 

Age group rem/uCi HCl d rem/ HCi HCl d DFi values& 

In utero .068 •.3 .061 .27 Adultb 

0 < 1 .118 1.29 .071 .n Infant 

1 - 10 .09.3 6 • .39 .066 4 • .5.3 Av. infant 

&: adult 

11 - 20 .09.3 6 • .57 .066 4.66 " >20 .068 8 • .51 .061 7.73 Adult 

EliDFi 23. 06 17.966 

~ee Chapter 2. . bNo credit taken for reduced biological half-life in pregnant women. 

1-131 

Ii X DFi 

DFi rem • 1 Reference for 

Age group rem/ uCl uCl d DFi valuesa 

In utero . 8 3.5 Max. estimate 

0 < 1 16 174 Newborn 

1 - 10 .5.7 391 Average from 

smooth curve 

11 - 20 2.;1 148 1.5 yr old 

>20 1 • .5 190 Adult 

j;li DFi 938 

asee Clh"lpter 2. 

34 

Table 22. Milk concentration at which cost= benefit 

(Population basis- value of i:IixOFi for 1000 persons) 

Sr-89 Sr-90 t-131 Cs-134 Cs-137 

Ell x DFi 10 • .58 2.55 938 23.1 17.96 

rem 1 

uCi •d' 

Value ($/rem) 22 22 40 200 200 

PA cost CONC. (Cost = Benefit) ( HCill) 

Stored Feed $0.039 .047 .002 .0003 .002.5 .003 

Farm Milk 0.30 •.36 .01.5 .0023 .018 .02.5 

Retail Milk 0 • .56 .68 .028 .0042 .034 .044 

Peak CONC. ( uCl/1) 

Preventive PAG .14 .009 .01.5 ' .1.5 .24 

Emergency PAG infant 1.4 .09 .1.5 1 • .5 2.4 

Emergency PAG adult 30 .4 2.0 .3.0 4..0 

.5.2 ECONOMIC IMPACT 

The Emergency Planning Zone (EPZ) for the ingestion pathway has been set at .50 miles 

(73). The area impacted that requires protective action is the major factor influencing cost. 

Assessment of the economic impact will be considered for the case of contamination ot· the 

milk pathway in one 22 • .SO Sector out to a distance of 50 miles. Table23 gives data on the 

annual sales of whole milk and total area of leading dairy States and selected States. The· 

annual milk sales in Wisconsin of 3 • .52 x 105 lbs. per sq. mile exceeds that of any other 

State and will be used to assess the economic impact. There may, of course, be individual 

counties and areas surrounding nuclear power plants where milk production exceeds the 

Wisconsin State average. The Wisconsin average should, however, represent a maximum for 

most areas of the United States. 

Tabie 23. Milk production of selected States 

(Statistical Abstract of the U.s., 1978) 

Whole milk sold Total area Milk ~r unit area 

State (109 lbs/;tear) (mill 105 lbs£mi2 

WI 20•.5 .56, 1.54 3 • .52 

VT 2.06 9,609 2.14 

NY 9.92 49,.576 2.00 

PA 7.37 4.5,333 1.64 

lA 4.07 .56,290 1 • .38 

CT •.59.5 .5, 009 1.19 

MN 9.27 84,068 1.10 

OH 4.43 41,222 1.08 

MI 4.63 .58,216 0.80 

CA 11.53 1.58,693 0.7.3 

MA 0.5.5 8,2.57 0.67 

NJ 0 • .52 7 1836 0.66 

Another important factor in assessing the economic impact of protective actions in che 

milk pathway is the length of time that such actions will be necessary. During most of the 

year in northern partS of the U.S., cattle will already be on stored feed and there will be no 

3.5 

additional costs for the stored feed protective action. For other situations and the Emergency PAG, the time over which protective actions will be necessary is a function of a 

number of parameters uni_que to each site and the causative accident. Thus, what are 

intended as conservative assumptions will be selected. The time behavior of 1-131 on 

pasture grass is controlled by the 8-day radioactive half-life and the 14-day weathering halflife (yielding an effective half-life of about 5 days). Milk which contains I-131 at the 

Emergency PAG of 0.15 JJCl/1 will be reduced to the cost = benefit concentration (farm 

value) of 0.0023 JJCi/1 about 30 days later. Obviously in most cases of an atmospheric 

release, those areas closer to the release point will have higher levels of contamination and 

longer tiMes of protective action. The NRC and EPA in the Planninb Basis Report NUREG0396 (NR(:, 1978) assume that radiation doses from the airborne plu:ne decrease according 

to the r· 1

• 5 factor. Use of this factor for contamination of pMture results in milk 

concentrations at 2 miles that are about 100 times that at 50 miles. For an effective halflife of 5 days this would require an additional 30-3.5 days of protective action at 2 miles 

over that at 50 miles to yield the same milk levels upon ceasing action. Although these 

models cannot be assumed to be rigorously accurate in a specific accident situation, they do 

indicate that action might be required for l or 2 months. 

NUREG-0396 notes that the dose from milk pathway is of the order of 300 times the 

thyroid dose from lnhalation'(74). Under this assumption (and above models), the food PAG's 

would be exceeded at hundreds of miles if protective action because of inhalation were 

required at 10 miles. It should be noted that the meteorological models that are empirically 

derived are not likely to be valid for such long distances. Further changes in wind direction 

and meteorological dispersion conditions may reduce the levels ot pasture contamination 

and the downwind distance. For assessing ecomomic impact, contamination of a 22•.5° 

Sector out to a distance of 50 miles will be arbitrarily assumed, even though actual 

contamination patterns are not likely to be similar. 

Under these assumptions 'we then have: 

Area (Circle - 50 mile radius) - 78.50 mi 2 

Area (22•.5° Sector - 50. mile) - 491 mi 2 

Milk Production - 3.52 x 10 5 lbs/mi 2 per year - 2.93 x 10 '+ lbs/mi 2 per month 

Production (22.5°/50 mi Sector)- 1.44 x 10 7 lbs./month 

Cost of Stored Feed - $0.017 per lb. milk 

Cost Impact (22.5'/50 mile Sector)- $2.46 x 10 5 per month 

' Thus, the direct cost of placing cows on stored feed within a 22.5° Sector out to 50 

miles based on farm value, would be about $0.25 million per month• The cost would be zero 

during that portion of the year and in geographical areas where cattle are already on stored 

feed. While such protective actions might be required for periods up to 2 months at areas 

near the accident site, such would not be the case at the greater distances which involve the 

major portion of the area. Condemnation of milk is the protective action of last resort for 

areas of very high contamination. As noted above, the farm value of milk is $0.30 per liter. 

Thus, the condemnation of milk at the Emergency PAG for a 22.5°/50 mile sector would 

have a cost of about $2 million for a month of protective action. Where I-131 is the only 

significant contaminant, whole milk can be diverted to manufactured products, such as 

powdered milk, which can be stored to-allow disappearance of the radioactivity. We do not 

have cost figures for this action. 

It is of interest to compare the arbitrary assumptions on land area used above to the 

contamination resulting from the Windscale accident. (NB: This was not a power reactor of 

the type presently used in the United States). According to Booker, the Windscale accident 

·resulted in milk values exceeding 0.015 lJCi/1 at about 200 kilometers or 125 miles 

36 

downwind (7,). Milk contamination was estimated as exceeding 0.01 tJCi/1 over 16,700 

km 2 or 64-00 mi z. Thus, the Windscale accident resulted in contamination exceeding 

the Preventive PAGover an area about 10 times greater than that assumed above. Protective 

actions were taken at Windscale at milk concentrations of 0.1 llCl/1 (afproximately 

the Emergency PAG) and involved an area of about 520 km 2 or 200 mi for periods 

of .3-6 weeks • 

.5.3 COST-EFPECTIVENESS ANALYSIS 

Cost-effectiveness analysis is defined as the economy with which a particular task may 

be carried out. · 

The data available for this analysis was obtained with the cooperation of the Nuclear 

Regulatory Commission. Briefly, the NRC employed the models cited in the Reactor Safety 

Study (7) to evaluate the agricultural costs and cumulative dose commitment that could 

occur under two accident conditions - a design basis for siting purposes and a PWR 7 

accident (7). A typical reactor site in the northeastern United States was envisioned. 

Unfortunately, the parameters employed are not directly comparable with the pathways and 

dosimetric parameters associated with the PAG's. Nevertheless, a good indication of the 

effects of taking a protective action (in this case the condemnation of milk) at specific 

interdiction levels can be ascertained. 

Figure S presents the agricultural costs at specific interdiction criteria. The costs are, 

for the most part, associated with the market value of milk. The il)terdicdon criteria are in 

terms of rem to an infant thyroid. From Figure 3, it can be seen that costs drop rapidly 

between 0.5 and 10 rem and more gradually after 20 rem. The ratio of costs for a design 

basis accident (siting) to a PWR 7 remains constant. 

Tat' 

• a_... ..... (....., 

• PWII7 

10 ~--~~--~----~----_........... .....~:P 10 20 30 40 50 60 

INTERDIC'nON ClUTERIA (rem-thyroid} 

Figure 3. Agricultural cost model accident. 

37 

Fi~re 4 is a graph of the dose commitment for a design basis accident and a PWR 7 

assummg protective action is initiated at specific interdiction levels. The dose commitments are accrued via external as well as internal exposure (inhalation and ingestion). 

Therefore, they do not exactly fit the situation described in the P AG's under consideration. 

The dose commitment rises rapidly when the interdiction criteria are between 0 • .5 and 20 

rem. The increase in dose commitment for a design basis accident is less rapid than for a 

PWR 7. Hence, at or above &1 interdiction criteria of 20 rem, savings in radiation dose are 

minimal compared to the savings accrued below 10 rem. 

10 20 30 40 so 

INTERDlcnQN ClUTERIA (rem·tfTyoic:l} 

Figure 4. Dose commitment model accident. 

5.4 SUMMARY AND CONCLUSION 

The milk concentration at which the population benefits (from dose avoided) equals the 

direct costs of stored feed is equivalent to about one-third of the Preventive PAG for strontium and to one-fiftieth or less for iodine-131 and cesium. If condemnation is based on 

retail milk value, then the respective concentrations are about one-half and one-fiftieth of 

the emergency PAG. Unless the indirect costs of implementing protective actions are 

significantly greater than the direct costs, it appears feasible to take protective actions at 

th~ respective PAG level and to continue such action to avoid about 90 percent of the 

projected dose for iodine and cesium. In the case of strontium contamination of milk, such 

action is only cost beneficial until the concentration is about 30 percent of the PAG 

response level. 

estimated costs of taking protective action within the Emergency Planning Zone (EPZ) 

for a 22.j0 Sector to 50 miles (about 500 mi2 ) is $2 million per month for condemnation 

(farm milk value) and $0.26 million per month for use of stored feed. In the case of 

38 

atmospher.ic dispersed contamination, protective action may have to continue for 2 months 

near the s1 te. 

The. recommended approach is to place all cows on stored feed to prevent the 

contamination of milk at significant levels, to divert iodine contaminated milk to 

manufactll"ed products chat have a long shelf life to allow radioactive decay, and only 

consider condemnation of milk exceeding the Emergency PAG. It appears that doses to the 

public can be limited to less than 10 percent· of the Preventive PAG (or less then 0.1.5 rem 

thyroid) by actions having direct costs of a few milion dollars for a significant accident. 

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39 

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40 

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41 

47. 	 Kahn, B. In: Conference on the Pediatric Significance of Peacetime Radioactive Fallout. Pediatrics p. 212 (1968). 

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Rapid Methods for Estimating Fission Product Concentrations in Milk. USDHEW, 

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Exposure Expected from Containment Release Accidents. BNL-NUREG/50882 

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PHS, Washington, DC (May 1962). 

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Radiation Accidents. World Health Organization, Geneva (1963). 

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Radioactive Fallout from Vegetables and Fruits During Processing by Normal and by 

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in Food. Radiological Health Dar:a 4(9):453 (September 1963). 

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90Sr Removal in Vegetables Prepared for Home Consumption. 

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Establishment, Harwell, Berkshire (1958). 

43 


CHAPTER7 

Implementing the Protective Action Guides for 


the Intermediate Phase: 


Exposure to Deposited Materials 


7.1 Introduction 

This chapter provides guidance for 

implementing the PAGs set forth in 

Chapter 4. It is for use by State and 

local officials in developing their 

radiological emergency response plans 

to protect the public from exposure to 

radiation from deposited radioactive 

materials. Due to the wide variety in 

types of nuclear incidents and 

radionuclide releases that could occur, 

it is not practical to provide 

implementing guidance for all 

situations. The guidance in this 

chapter applies primarily to 

· radionuclides that would be involved in 

incidents at nuclear power plants. It 

may be useful for radionuclides from 

incidents at other types of nuclear 

facilities or from incidents not 

involving fixed facilities (e.g., 

transportation accidents).However, 

specific implementation procedures for 

incidents other than those at nuclear 

power plants should be developed by 

planners on a case-by-case basis. 

Contrary to the situation during 

the early phase of a nuclear incident, 

when decisions usually must be made 

and implemented quickly by State and 

local officials before Federal assistance 

is available, many decisions and 

actions during the intermediate phase 

can be delayed until Federal resources 

are present, as described in the Federal 

Radiological Monitoring and 

Assessment Plan (FE-85). Because of 

the reduced level of urgency for 

immediate implementation of these 

protective actions, somewhatless detail 

may be needed in State radiological 

emergency response plans than is 

required for the early phase. 

At the time of decisions on 

relocation and early decontamination, 

sheltering and evacuation should have 

already been completed to protect the 

public from exposure to the airborne 

plume and from high exposure rates 

from deposited materials. These 

protective actions may have been 

implemented prior to verification ofthe 

path of the plume and therefore some 

persons may have been unnecessarily . 

evacuated from areas where actual 

doses are much lower than were 

projected. Others who were in the 

path of the plume may have been 

sheltered or not protected at all. 

During the intermediate phase of the 

response, persons must be relocated 

from areas where the projected dose 

exceeds the PAG for relocation, and 

other actions taken to reduce doses to 

persons who are not relocated from 

contaminated areas. Persons 
evacuated from areas outside the 

relocation zone may return. 

7 .1.1 Protective Actions 

The main protective actions for 

reducing exposure of the public to 

deposited radioactivity are relocation, 

decontami- nation, shielding, time 

limits on exposure, and control of the 

spread of surface contamination. 

Relocation is the most effective, and, 

usually, the most costly and disruptive. 

It is therefore only applied when the 

dose is sufficiently high to warrant it. 

The others are generally applied to 

reduce exposure ofpersons who are not 

relocated, or who return from 

evacuation status to areas that 

received lower levels of deposited 

radioactivity. This chapter provides 

guidance for translating radiological 

conditions in the environment to 

projected dose, to provide the basis for 

decisions on the appropriate protective 

actions. 

7 .1.2 Areas Involved 

Figure 7-1 provides a generalized 

example of the different areas and 

population groups to be dealt with. 

The path ofthe plume is assumed to be 

represented by area 1. In reality, 

variations in meteorological conditions 

would almost certainly produce a more 

complicated shape, but the same 

principles would apply. 

Because of plant conditions and 

other considerations prior to or after 

the release, persons will already have 

been evacuated from area 2 and 

sheltered in area 3. Persons who have 

been evacuated from or sheltered in 

areas 2 and 3, respectively, as 

precautionary actions for protection 

from the plume, but whose homes are 

outside the plume deposition area (area 

1), may retum to their homes as soon 

as environmental monitoring verifies 

the boundary of the area that received 

deposition (area 1). 

Area 4 is designated a restricted 

zone and is defined as the area where 

projected doses are equal to or greater 

than the relocation PAG. Persons 

residing just outside the boundary of 

the restricted zone may receive a dose 

near the P AG for relocation if 

decontamination or other dose 

reduction efforts are not implemented. 

Area 1, with the exception of the 

restricted zone, represents the area of 

contamination that may continue to be 

occupied by the general public. 

Nevertheless, there will be 

contamination levels in this area that 

will require continued monitoring and 

dose reduction efforts other than 

relocation. 

The relative positions of the 

boundaries shown in Figure 7-1 depend 

on areas evacuated and sheltered, and 

the radiological characteristics of the 

release. For example, area 4 (the 

restricted zone) could fall entirely 

inside area 2 (area evacuated), so that 

the only persons to be relocated would 

be those residing in area 4 who were 

either missed in the evacuation process 

or who, because of the high risk for 

their evacuation, had remained 

sheltered during plume passage. 

7-2 

PLUME TRAVELDIRECTION 

ARBITRARY SCALE 

LEGEND

,.-, 1. PLUME DEPOSITION AREA. L_J 

~ 2. AREA FROM WHICH POPULATION IS EVACUATED. 

~ 3. AREA IN WHICH POPULATION IS SHELTERED. 

m4. AREA FROM WHICH POPULATION IS RELOCATED (RESTRICTED ZONE). 

FIGURE 7-1. RESPONSE AREAS. 
At the time the restricted zone is 

established, a temporary buffer zone 

(not shown in Figure 7 -1) may be 

needed outside portions of the 

restricted zone in which occupants will 

not be allowed to return until 

monitoring confirms the · stability of 

deposited contamination. Such zones 

would be near highly contaminated 

areas in the restricted zone where 

deposited radionuclides might be 

resuspended and then redeposited 

outside the restricted zone. This could 

be especially important at locations 

close to the incident site where the 

radioactivity levels are high and the 

restricted zone may be narrow. The 

extent ofthe buffer zone will depend on 

local conditions. Similarly, a buffer 

zone encompassing the most highly 

contaminated areas in which persons 

are allowed to reside may be needed. 

This area should be monitored 

routinely to assure acceptability for 

continued occupancy. 

7 .1.3 Sequence of Events 

Following passage of the airborne 

plume, several tasks, as shown in 

Figure 7-2, must be accomplished 

simultaneously to provide for timely 

protection of the public. The decisions 

on the early task of relocating persons 

from high exposure rate areas must be 

based on exposure rate measurements 

and dose analyses. It is expected that 

monitoring and dose assessment will be 

an on-going process, with priority given 

to the areas with the highest exposure 

rate. The general sequence of events is 

itemized below, but the time frames 

will overlap, as demonstrated in Figure 

7-2. 

1. Based on environmental data, 

determine the areas where the 

projected one-year dose will exceed 2 

rem and relocate persons from those 

areas, with priority given persons in 

the highest exposure rate areas. 

2. Allow persons who were evacuated 

to return immediately to their 

residences if they are in areas where 

field gamma measurements indicate 

that exposure rates are near normal 

background levels (not in excess of 

twice the normal background in the 

area before the incident). If, however, 

areas ofhigh deposition are found to be 

near areas with low deposition such 

that resuspended activity could drift 

into the occupied areas, a buffer zone 

should be established to restrict 

occupancy until the situation is 

analyzed and dose projections are 

confirmed. 

3. Determine the location of the 

isodose line corresponding to the 

relocation PAG, establish the boundary 

ofthe restricted zone, and relocate any 

persons who still reside within the 

zone. Also, convert any evacuees who 

reside within the restricted zone to 

relocation status. Evacuated persons 

whose residence is in the area between 

the boundary of the plume deposition 

and the boundary to the restricted zone 

may return gradually as confidence is 

gained regarding the projected dose in 

the area. 

4. Evaluate the dose reduction 

effectiveness ofsimple decontamination 
t/l.

a: 

:::) 

0 

0 

0 

.... 

z 

w -=l c I 

01 0 

0 

c( 

PERIOD OF 


RELEASE, 


DISPERSION, 


DEPOSITION, 


SHELTERING, 


EVACUATION, 


AND ACCESS 


CONTROL 


(NO TIME SCALE) 


CONDUCT AERIAL AND GROUND SURVEYS. DRAW ISODOSE RATE LINES. 

IDENTIFY HIGH DOSE RATE AREAS. CHARACTERIZE CONTAMINATION. 

RELOCATE POPULATION FROM HIGH DOSE RATE AREAS. 

~ALLOW IMMEDIATE RETURN OF EVACUEES TO NONCONTAMINATED AREAS. 

ESTABLISH RESTRICTED ZONE BOUNDARY AND CONTROLS. 

c RELOCATE REMAINING POPULATION FROM WITHIN RESTRICTED ZONE. 

w GRADUALLY RETURN EVACUEES UP TO RESTRICTED ZONE BOUNDARY • .... 

..J 

w 

0.. 

- COND~CT D-CON AND SHIELDING EVALUATIONS AND ESTABLISH PROCEDURES 

::E FOR REDUCING EXPOSURE OF PERSONS WHO ARE NOT RELOCATED. 0 

0 

PERFORM DETAILED ENVIRONMENTAL MONITORIHG . z 

0 PROJECT DOSE BASED ON DATA. 

i= 

iii 

­

DECONTAMINATE ESSENTIAL FACILITIES AND THEIR ACCESS ROUTES. 0 

0.. RETRIEVE VALUABLE AND ESSENTIAL RECORDS AND POSSESSIONS. 

w 

­

c 

REESTABLISH OPERATION OF VITAL SERVICES. 

BEGIN RECOVERY ACTIVITIES. 

MONITOR AND APPLY 


ALARA 

CONTAMINATED 

IN OCCUPIED 

AREAS. 


-~ 

0.1 1.0 .10 100 

TIME AFTER DEPOSITION (DAYS) 

FIGURE 7-2. POTENTIAL TIME FRAME OF RESPONSE TO A NUCLEAR INCIDENT. 

techniques and of sheltering due to 

partial occupancy of residences and 

workplaces. Results of these 

evaluations may influence 

recommendations for reducing exposure 

rates for persons who are not relocated 

from areas near, but outside, the 

restricted zone. 

5. Establish a mechanism for 

controlling access to and egress from 

the restricted zone. Typically this 

would be accomplished through control 

points at roadway accesses to the 

restricted zone. 

6. Establish monitoring and 

decontamination stations. to support 

control of the restricted zone. 

7. Implementsimple decontamination 

techniques in contaminated areas 

outside the restricted zone, with 

priorities for areas with higher 

exposure rates and for residences of 

pregnant women. 

8. Collect data needed ·to establish 

long-term radiation protection criteria 

for recovery and data to determine the 

effectiveness of various 

decontamination or other recovery 

techniques. 

9. Begin operations to recover 

contaminated property inthe restricted 

zone. 

7.2 Establishment of Isodose-rate 

Lines 

As soon as Federal or other 

assistance is available for aerial and 

ground ·monitoring, a concentrated 

effort should begin to establish 

isodose-rate lines on maps and the 

identification of boundaries to the 

restricted zone. Planning for this effort 

should include the development of 

standard maps that can be used by all 

of the involved monitoring and dose 

assessment organizations to record 

monitoring data. 

Aerial monitoring (e.g., the 

Department of Energy Aerial 

Monitoring Service) can be used to 

collect data for establishing general 

patterns of radiation exposure rates 

from deposited radioactive material. 

These data, after translation to 

readings at 1 meter above ground, may 

form the primary basis for the 

development of isodose lines out to a 

distance where aerial monitoring shows 

no radiation above twice natural 

background levels. Air sample 

measurements will also be needed to 

verify the contribution to dose from 

inhalation of resuspended materials. 

Gamma exposure rates measured 

at 1 meter will no doubt vary as a 

function of the location of the 

measurement within a very small area. 

This could be caused by different 

deposition rates for different types of 

surfaces (e.g., smooth surfaces versus 

heavy vegetation). Rinsing or 

precipitation could also reduce levels in 

some areas and raise levels in others 

where runoffsettles. In general, where 

exposure rates vary within designated 

areas, the higher values should be used 

for dose projection for persons within 

these areas unless judgment can be 

7-6 

used to estimate an appropriate 

average exposure rate. 

Measurements made at 1 meter to 

project whole body dose from gamma 

radiation should be made with 

instruments of the "closed window" 

type so as to avoid the detection ofbeta 

radiation. Although beta exposure will 

contribute to skin dose, its contribution 

to the overall risk ofhealth effects from 

the radionuclides expected to be 

associated with reactor incidents 

should not be controlling in comparison 

to the whole body gamma dose (AR-89). 

Special beta dose analyses may be 

appropriate when time permits to 

determine its contribution to skin dose. 

Since beta dose rate measurements 

require sophisticated equipment that is 

generally not available for field use, 

beta dose to the skin should be limited 

based on measured concentrations of 

. radionuclides per unit area. 

7.3 Dose Projection 

The primary dose of interest for 

reactor incidents is the sum of the 

effective gamma dose equivalent from 

external exposure and the committed 

effective dose equivalent from 

inhalation. The exposure periods of 

interest are first year, second year, and 

up to 50 years after the incident. 

Calculation of the projected 

gamma dose from measurements will 

require knowledge of the principal 

radionuclides contributing to exposure 

and their relative abundances. 

Information on these radiological 

characteristics can be compiled either 

through the use of portable gamma 

spectrometers or by radionuclide 

analysis of environmental samples. 

Several measurement locations may be 

required to determine whether any 

selective radionuclide deposition 

occurred as a function of weather, 

surface type, distance from the point of 

release, or other factors. As part ofthe 

Federal Radio- logical Monitoring and 

Assessment Plan (FE-85), the U. S. 

Department of Energy and the U. S. 

Environmental Protection Agency have 

equipment and procedures to assist 

State officials in performing 

environmental measurements, 

including determination of the 

radiological characteristics ofdeposited 

materials. 

The gamma exposure rate may 

decrease rapidly if deposited material 

includes a significant fraction of 

short-lived radionuclides. Therefore, 

the relationship between instantaneous 

exposure rate and projected first- and 

second-year annual or the 50-year 

doses will change as a function oftime, 

and these relationships must be 

established for the particular mix of 

deposited radioactive materials present 

at the time ofthe gamma exposure rate 

measurement. 

For incidents involving releases 

from nuclear power plants, gamma 

radiation from deposited radioactive 

materials is expected to be the 

principal exposure pathway, as noted 

above. Other pathways should also be 

evaluated, and their contributions 

considered, if significant. These may 

include inhalation of resuspended 

material and beta dose to the skin. 

7-7 

Exposure from ingestion of food and 

water is normally limited 

independently of decisions for 

relocation and decontamination (see 

Chapters 3 and 6). In rare instances, 

however, where withdrawal of food 

and/or water from use would, in itself, 

create a health risk, relocation may be 

an appropriate protectiye action for 

protection from exposure via ingestion. 

In this case, the committed effective 

dose equivalent from ingestion should 

be added to the projected dose from 

other exposure pathways for decisions 

on relocation. 

The following sections provide 

methods for evaluating .the projected 

dose from whole body external 

exposure and from inl;lalation of 

resuspended particulate material, 

based on environmental information. 

7.3.1 Projected External Gamma Dose 

Projected whole body external 

gamma doses at 1 meter height at 

particular locations during the first 

year, second year, and over the 50-year 

period after the incident are the 

parameters of interest. The 

environmental information available 

for calculating these doses is expected 

to be the current gamma·exposure rate 

at 1 meter height and the relative 

abundance of each radionuclide 

contributing significantly to that 

exposure rate. Calculational models 

are available for predicting future 

exposure rates as a function of time 

due to radioactive decay and 

weathering. Weathering is discussed 

in WASH-1400, Appendix VI (NR-75), 

and information on the relationship 

between surface concentrations and 

gamma exposure rate at 1 meter is 

addressed in reference (D0-88). 

Following the incident, 

experiments should be conducted to 

determine the dose reduction factors 

associated with part-time occupancy of 

dwellings and workplaces, and with 

simple, rapid, decontamination 

techniques, so that these factors can 

also be applied to the calculation of 

dose to persons who are not relocated. 

However, these factors should not be 

included in the calculation of projected 

dose for decisions on relocation. 

Relocation decisions can generally 

be made on the basis of the first year 

projected dose. However, projected 

doses during the second year and over 

50 years are needed for decisions on 

the need for other protective actions for 

persons who are not relocated. Dose 

conversion factors are therefore needed 

for converting environmental 

measurements to projected dose during 

the first year, second year, and over 50 

years following the incident. Of the 

two types of environmental 

measurements that can be made to 

project whole body external gamma 

dose, gamma exposure rate in air is the 

easiest to make and is the most 

directly linked to gamma dose rate. 

However, a few measurements· of the 

second type (radionuclide 

concentrations on surfaces) will also be 

needed to properly project decreasing 

dose rates. 

Tables 7-1 and 7-2 provide 

information to simplify development 

7-8 

Table 7-1 Gamma Exposure Rate and Effective Dose Equivalent (Corrected for Radioactive Decay and 

Weathering) due to an Initial Uniform Concentration of 1 pCilm2 on Ground Surface 

Integrated dose 

(weathering factor included)b 

Initial exposurea 

rate at 1m year one year two 0-50 years 

Half-life (mR/h (mremper (mremper (mrem per 

Radionuclide (hours) per pCi/m2

) pCi/m2

) pCi/m2

) .pCi!m2

) 

Zr-95 1.54E+03 1.2E-08 3.3E-05 4.0E-07 3.4E-05 

Nb-95 8.41E+02 1.3E-08 (b) (b) (b) 

Ru-103 9.44E+02 8.2E-09 7.1E-06 0 7.1E-06 

Ru-106 8.84E+03 3.4E-09 1.2E-05 3.7E-06 1.8E-05 

Te-132 7.82E+01 4.0E-09 3.2E-06 0 3.2E-06 

-::t 

I I-131 1.93E+02 6.6E-09 1.3E-06 0 	 1.3E-06 ~ I-132 2.30E+00 3.7E-08 (b) (b) (b) 

I-133 2.08E+01 l.OE-08 2.1E-07 0 2.1E-07 

I-135 6.61E+00 2.4E-08 1.6E-07 0 1.6E-07 

Cs-134 1.81E+04 2.6E-08 1.0E-04 4.7E-05 2.4E-04 

Cs-137 2.65E+05 1.0E-08 4.5E-05 2.9E-05 6.1E-04 

Ba-140 3.07E+02 3.2E-09 1.1E-05 0 1.1E-05 

La-140 4.02E+01 3.5E-08 (b) (b) (b) 

aEstimated exposure rate at 1 meter above contaminated ground surface. Based on data from reference (D0-88). 

bRadionuelides that have short-lived daughters (Zr/Nb-95, Te/1-132, Ru/Rh-106, Cs-137/Ba-137m, Ba/La-140) are assumed to quickly 

reach equilibrium. The integrated dose factors listed are the effective gamma dose due to the parent and the daughter. Based on data 

from reference (D0-88). 
Table 7-2 Exposure Rate and Effective Dose Equivalent (Corrected. for Radioactive Decay) due to an Initial 

Concentration of 1 pCi/m2 on Ground Surface 

Integrated dose 


Initial exposurea (weathering factor not included)b 


rate at 1m year one year two 0-50 years 

Radionuclide 

Half-life 

(hours) 

(mR/h 

per pCi/m2

) 

(mremper (mremper (rorem per 

pCi/m2

) pCilm2

) pCilm2) 

Zr-95 1.54E+03 1.2E-08 3.8E-05 8.0E-07 3.9E-05 

Nb-95 8.41E+02 1.3E-08 (b) (b) (b) 

Ru-103 9.44E+02 8.2E-09 7.8E-06. 0 7.8E-06 

Ru-106 8.84E+03 3.4E-09 1.5E-05 7.6E-06 3.0E-05 

Te-132 7.82E+01 . 4.0E-09 3.3E-06 0 3.3E-06 

....:r 

I 

J-1 	 I-131 1.93E+02 6.6E-09 1.3E-06 0 1.3E-06 

0 	 I-132 2.30E+00 3.7E-08 (b) (b) (b) 

I-133 2.08E+01 1.0E-08 2.1E-07 0 2.1E-07 

I-135 6.61E+00 2.4E-08 1.6E-07 0 1.6E-07 

Cs-134 1.81E+04 2.6E-08 1.3E-04 9.6E-05 4.7E-04 

Cs-137 2.65E+05 1.0E-08 6.0E-05 5.9E-05 1.8E-03 

Ba-140 3.07E+02 3.2E-09 1.2E-05 0 1.2E-05 

La-140 4.02E+01 3.5E-08 (b) (b) (b) 

aEstimated exposure rate at 1 meter above contaminated ground surface. Based on data from reference (D0-88). 

bRadionuclides that have short-lived daughters (Zr/Nb-95, Ru/Rh-106, Te/1-132, Cs-137/Ba-137m, Ba/La-140) are assumed to quickly 

reach equilibrium. The integrated dose factors listed are the effective gamma dose due To the parent and-the (faughter. Based on data 

from reference (D0-88). 
of dose conversion factors through the 

use of data on the radionuclide mix, as 

determined from environmental 

measurements. These tables list the 

deposited radionuclides most likely to 

be the major contributors to dose from 

incidents at nuclear power facilities. 

In addition to providing integrated, 

effective doses per unit of surface 

concentration, they provide, in column 

three, the exposure rate (mRJh) in air 

per unit of surface contamination. All 

exposure rate values are based on 

those given in reference (D0-88). They 

were estimated from the total body 

photon dose rate conversion factors for 

exposure at 1 m above the ground 

surface. Since the ratio of effective 

dose to air exposure is about 0. 7, 

dividing the effective dose rate by 0. 7 

results in an estimate of the exposure 

rate in air. The integrated effective 

doses are based on dose conversion 

factors also listed in reference (D0-88). 

Table 7-1 takes into accoimt both 

radioactive decay and weathering, 

whereas the values inTable 7-2 include 

only radioactive decay. The effect of 

weathering is uncertain and will vary 

depending on the type ofweather, type 

ofsurface, and the chemical form ofthe 

radionuclides. The user may choose 

either table depending on the 

confidence accorded the assumed 

weathering factors. 

The following steps can be used to 

develop dose conversion factors to 

calculate projected future doses from 

gamma exposure rate measurements 

for specific mixes of radionuclides: 

1. Using spectral analysis of gamma 

emissions from an environmental 

sample of deposited radioactivity, 

determine the relative abundance of 

the principal gamma emitting 

radionuclides. Analyses of uniform 

samples from several different locations 

may be necessary to determine whether 

the relative concentrations of 

radionuclides are constant. The results 

may be expressed as the activity (pCi) 

of each radionuclide in the sample. 

2. Multiply each activity from step 1 

by the corresponding values in column 

3 of Table 7-1 or Table 7-2 (depending 

on whether or not weathering is to be 

considered) to determine the relative 

contribution to. the gamma exposure 

rate (mRJh) at 1-meter height for e~ch 

radionuclide. Sum the results for each 

sample. 

3. Similarly, multiply each activity 

from step 1 by the corresponding 

values in columns 4, 5, and 6 to 

determine the 1st-year, 2nd-year, and 

50-year relative integrated doses 

contributed by each radionuclide. Sum 

these results for ..each sample. 

Radionuclides listed in Tables 7-1 and 

7-2 that have short-lived daughters 

(Zr/Nb-95, Te/I-132, Ru/Rh-106, 

Cs-137/Ba-137m, Ba/La-140) were 

assumed to be in equilibrium with 

their daughters when the tabulated 

values for integrated dose were 

calculated. Since. the values for· the 

parents include the total do~e from the 

parent and the daughter, do not double 

count these daughters in the sum.· (In 

the cases of Cs-137/Ba-137m, and 

· Ru-106/Rh-106, 	the parents are not 

gamma emitters, so the listed exposure 

rates and doses are actually those from 

the daughters alone.) 

7-11 

4. Using the results from steps 2 and 

3 the relevant dose conversion factors, 

DCF, for each sample are then given 

by: 

n 

:E Hi 

DCF = -

1

­

n 

:E xi 

1 

where Hi = effective dose equivalent for radionuclide i 

(mrem), 

}( = gamma exposure rate for 

radionuclide i (m.Rih) 

n = the number of radionuclides in the sample. 

Since the samples represented in the 

numerator and denominator are 

identical, the effect of the size of the 

sample cancels. 

These dose conversion factors may 

be applied to any measured gamma 

exposure rate for which the relative 

concentrations ofradionuclides are the 

same as those in the sample that was 

analyzed. 

The following example 

demonstrates the use of the above 

procedures for calculating a DCF. For 

purposes of the example it is assumed 

that environmental measurements 

revealed a mix of radionuclides as 

shown in column 3 of Table 7-3. The 

(relative) exposure rate conversion 

factors in column 4 of Table 7-3 ~e 

taken from column 3 ofTable 7-1. The 

(relative) exposure rates in column 5 

are the products of columns 3 and 4. 

The (relative) doses for individual 

radionuclides in columns 6, 7, and 8 

were calculated by multiplying the 

concentrations in column 3 by the dose 

conversion factors in columns 4, 5, and 

6 ofTable 7-1, respectively. (Columns 

4, 5, and 6 of Table 7-2, which do not 

include weathering, could have been 

used instead of those in Table 7-1.) 

For this example, the conversion 

factor for dose in the first year was 

obtained for the assumed radionuclide 

mix from the totals of columns 5 and 6 

of Table , 7-3, which indicate that a 

calculated dose of 0.023 mrem in the 

first year corresponds to an initial 

exposure rate of 1.5E-4 mR/h. 

Therefore, the first year dose 

conversion factor (DCF1) for this 

example is 150 mrem for each mR/h 

measured at the beginning of the 

period. 

This DCF may be multiplied by 

any gamma exposure rate 

measurement to estimate the dose in 

the first year for locations where the 

exposure rate is produced by a 

radionuclide mix the same as assumed 

for calculating the DCF, and where 

weathering affects the exposure rate in 

the same manner as assumed. For 

example, if a gamma exposure rate 

measurement were taken at the 

location where the contamination 

sample in Table 7-3 was taken, this 

exposure rate could be multiplied by 

the DCF calculated in the above 

example to obtain the projected first 

year dose at that point. Based on the 

example analysis and a relocation PAG 

of 2 rem, for this case the exposure 

rate at the boundary of the restricted 

zone should be no greater than 

7-12 

Table 7-3 Examplea Calculation of Dose Conversion Factors for Gamma Exposure Rate Measurements Based on 

Measured Isotopic Concentrationsb . · 

Calculated effective dose at 1 meter Measured mRJh2. Calculated 

Radionuclide Half-life concentration Exposure rate year one year two 50 yea_rs pCilm2 

(hours) (pCi/sampled) at 1 m (mR/hr) (mrem) (mrem) (mrem) 

I-131 1.93E+2 2.6E+2 6.6E-9 1.7E-6 3.3E-4 0 3.3E-4 

Te-132 7.8E+1 3.6E+3 4.0E-9 1.4E-5 1.2E-2 0 1.2E-2 

I-132 2.3 3.6E+3 3.7E-8 1.3E-4 (e) (e) (e) 

Ru-103 9.44E+2 2.2E+2 8.2E-9 1.8E-6 1.6E-3 0 1.6E-3 

Rh-106f 8.84E+3 5.0E+1 3.4E-9 1.7E-7 5.8E-4 1.9E-4 9.2E-4 

...:a Cs-134 1.81E+4 6.8E+1 2.6E-8 1.8E-6 6.9E-3 3.2E-3 1.6E-2 I 

..... 

co Ba-137mr 2.65E+5 4.2E+1 1.0E-8 4.2E-7 1.9E-3 1.2E-3 2.6E-2 

Totals 1.5E-4 2.3E-2 4.6E-3 5.6E-2 

"The data in this table are only examples to demonstrate a calculational process. The results should not be used in the prediction of 

relationships that would exist following a nuclear incident. 

bCalculations are based on data inTable 7-1, which includes consideration of both radioactive decay and weathering. 

"External exposure rate factors at 1 meter above ground for a person standing.on contaminated ground, based on data in Table·7-1. 

mrhe size of the sample is not important for this analysis because only the relative concentrations are needed to calculate the ratio of 

integrated dose to exposure rate. 

"The integrated dose from.I-132 is not calculated separately because it is the short-lived daughter ofTe-132, and is assumed to be in 

equilibrium with it. The assumed quantity present is that for a daughter in equilibrium with the parent. 

This is a short lived daughter of a parent that has no gamma emissions and the halflife given is that of the parent. 
2000 mrem = 13 mR!h, 

150 mrem/mR/h 

if the contribution to effective dose 

from inhalation of resuspended 

radioactive materials is zero (See 

Section 7 .3.2). The example DCF for 

the second year and 50 years are 

obtained by a similar process, yielding 

DCFs of 31 and 370 mrem per mR/h, 

respectively. 

The ratio ofthe second year to first 

year dose is 31/150 = 0 .21. If this is 

the case, persons not relocated on the 

basis of a 2 rem PAG should, for this 

example, receive no more than 0.21 x 2 

= 0.4 rem in year 2. Similarly, the 

dose in fifty years should be no more 

than 4.9 rem. Actual doses should be 

less than these values to the extent 

that exposure rates are reduced by 

shielding from structures and by 

decontamination. · 

Prior to reaching conclusions 

regarding the gamma exposure rate 

that would correspond to the relocation 

PAG, one would need to verify by 

multiple sampling the consistency of 

the relative abundance of specific 

radionuclides as well as the· relative 

importance ofthe inhalation pathway. 

Dose conversion factors will change 

as a function of the radiological 

makeup of the deposited material. 

Therefore, dose conversion factors must 

be calculated based onthe best current 

information following the incident. 

Since the relative concentrations will 

change as a function of time due to 

different decay rates, dose conversion 

factors must be calculated for specific 

measurement times of interest. By 

calculating the decay of the original 

sample(s), a plot of dose conversion 

factors (mrem per m.Rih) as a function 

of time after the incident can be 

developed. As weathering changes the 

radionuclide mix, and as more is 

learned about other dose reduction 

mechanisms, such predictions of dose 

conversion factors may require 

adjustment. 

7 .3.2 Inhalation Dose Projection 

It can be shown, for the mixture of 

radionuclides assumed to be deposited 

from postulated reactor incidents, and 

an assumed average resuspension 

factor of 10"6 m·I, that the effective dose 

from inhalation is small compared to 

the corresponding effective dose from 

external exposure to gamma radiation. 

However, air sample analyses should 

be performed for specific situations 

(e.g., areas of average and high 

dynamic activity) to determine the 

magnitude of possible inhalation 

exposure. The 50-year committed 

effective dose equivalent (H50) resulting 

from the inhalation of resuspended 

airborne radioactive materials is 

calculated as follows: 

H50 = I x DCF (1) 

where 

I =total intake (p.Ci), and 

DCF =committed effective dose 

equivalent per unit intake 

(rem/p.Ci). 

It is assumed that the intake rate 

will decrease with time due to 

7-14 

radioactive decay and weathering. No 

model is available to calculate the 

effect ofweathering on resuspension of 

deposited materials, so the model 

developed for calculating its effect on 

gamma exposure rate (NR-75) is 

assumed to be valid. This should 

provide conservative results. The total. 

intake (1) from inhalation over time t 

may be calculated for each 

radionuclide, using the following 

equation: 

I = BCo ~ 0.63 (1-e -(t.,.+A.) t) 

LA.l +A2 

+ 0.37 -e-(t.,.+~)t}] (2) 

A.1 +A.3 

where 

B = average breathing rate for 

adults 

= 1.05E+4 m3/a (EP-88), 

C0 = 	initial measured concentration of 

the resuspended radionuclide in 

air (pCi/m3), 

t = 	 time during which radionuclides 

are inhaled (a), 

A.1 = 	 radioactive decay constant (a.1), 

A.2 = assumed weathering decay 

constant for 63 percent of the 

deposited activity, taken as 1.13 

a·1 (NR-75), and 

A.3 = assumed weathering decay 

constant for 37 percent of the 

deposited activity, taken as 7A8 

E-3 a·1 (NR-75). 

Table 7-4 tabulates results 

calculated.using the above assumptions 

for weathering. The table contains 

factors relating the committed effective 

dose from exposure during the first and 

second years after the incident to an 

initial air concentration of 1 pCi/m3 for 

each of the principal radionuclides 

expected to be of concern from reactor 

incidents. The dose conversion factors 

are taken from FGR-11 (EP-88). 

Parent radionuclides and their short 

lived daughters are grouped together 

because these dose conversion factors 

are based on the assumption that both 

parents and daughters will occur in 

equal concentrations and will decay 

with ,the half life of the parent. 

Therefore, measured concentrations of 

the short lived daughters should. be 

ignored and only the parent 

concentrations should be used in 

calculating long term projected doses. 

Table 7-4 lists factors which 

include the effects of both weathering 

and radioactive decay, as well as those 

that include only the effects of 

radioactive decay. Users ofthese data 

should decide which factors to use 

based on their confidence on the 

applicability of the weathering models 

used (NR-75) to their environment. 

The committed effective dose 

equivalent is calculated by multiplying 

the measured initial air concentration 

(pCi/m3

) for each radionuclide of 

concern by the appropriate factor from 

the table and summing the results. 

This sum may then be added to the 

corresponding external whole body 

gamma dose to yield the total com7-15 

Table 7~4 Dose Conversion Factors for Inhalation of Resuspended Materiala 

Committed effective dose equivalent per unit air concentration 

at the begi...nning of year one (mrem per pCi/m3

) 

Considering radioactive Considering radioactive 

decay and weathering decay only 

Radionuclideb Lung classc Year one Year two 	 Year one Year two 

Sr-90/Y~90 Y/Y 1.0E+1 5.5E 0 1.4E+l 1.3E+1 

....:r I Zr-95/Nb~95 Y/Y 6.5E-2 7.9E-2 ........ 	 y
 0') 	 Ru-103 1.3E-2 1.5E-2 

Ru-106/Rh-106 YID 2.8E 0 1.0E 0 3.7E 0 1.9E 0 

Te-132/I-132 WID 1.3E-3 1.3E-3 

I-131 D 1.1E-2 1.1E-2 

Cs-134 D 3.1E-1 1.5E-1 4.1E-1 3.0E-1 

Cs-137/Ba-137m DID 2.5E-1 1.4E-1 3.3E-1 3.2E-1 

Ba-140/La-140 D/W 4.4E-3 4.7E-3 

Ce-144/Pr-144 Y/Y 2.0E 0 4.2E-1 2.7E 0 9.8E-1 

acalculated using the dose factors in EP-88, Table 2.1. 

bShort lived daughters are not listed separately because the entries include the dose from both the daughter and the parent. These 

factors are based on the concentration of the parent only, at the beginning of the exposure period. 

'The lung clearance class chosen is that which results in the highest dose conversion factor. 
mitted effective dose equivalent from 

these two pathways. 

The PAGs include a guide for dose 

to skin which is 50 times the 

magnitude of the P AG for effective 

dose. Analysis (AR-89) indicates that 

this guide is not likely to be controlling 

for radionuclide mixes expected to be 

associated with nuclear power plant 

incidents. Dose conversion factors are 

provided in Table 7-5 for use in case of 

incidents where the source term 

consists primarily of pure beta 

emitters. The skin dose from each 

radionuclide may be calculated by 

multiplying the measured 

concentration (pCi/m2

) by the 

corresponding dose conversion factor in 

the table. This will yield the first year 

beta dose to the skin at one meter 

height from exposure to deposited 

materials plus the estimated dose to 

the skin from materials deposited on 

the skin as a result of being in the · 

contaminated area. These factors are 

calculated based on information in 

Reference AR-89, which used 

weathering factors that apply for 

gamma radiation and would, therefore, 

be conservative for application to beta 

radiation. Calculated doses based on 

these factors should be higher than the 

doses that would be received. 

7.4 Priorities 

In most cases protective actions 

during the intermediate phase will be 

carried out oyer a period ofmany days. 

It is therefore useful to consider what 

priorities are appropriate. Further, for 

situations where the affected area is so 

large that it is impractical to relocate 

all of the public, especially from areas 

exceeding the PAGs by only a small 

amount, priorities are needed for 

protective actions. The following 

priorities are appropriate: 

1. As a first priority, assure that all 

·persons are protected from doses that 

could cause acute health effects from 

all. exposure pathways, including 

previous exposure to the plume. 

2. Recommend the application of 

simple decontamination techniques and 

that persons remain indoors as much 

as possible to reduce exposure rates. 

3. Establish priorities for relocation 

with emphasis on high exposure rate 

areas and pregnant women (especially 

those in the 8th to 15th week of 

pregnancy). 

7.5 Reentry 

Mter the restricted zone is 

established, persons will need to 

reenter for a variety of reasons, 

including recovery activities, retrieval 

of property, security patrol, operation 

of vital services, and, in some cases, 

care and feeding of farm and other 

animals. It may be possible to quickly 

decontaminate access ways to vital 

institutions and businesses in certain 

areas so that they can be occupied by 

adults either for living (e.g., 

institutions such as nursing homes, 

and hospitals) or for employment. 

Clearance · of these areas for such 

occupancy Will require dose reduction 

to comply with occupational exposure 

7-17 

Table 7-5 Skin Beta Dose Conversion Factors for Deposited Radionuclidesa 

Radionuclide 

Co-58 

Co-60 

Rb-86 

Sr-89 

Sr-90 

Y-90 

Y-91 

Zr-95 

Nb-95 

Mo-99 

Tc-99m 

Ru-103 

Ru-106c 

Rh-105 

Sb-127 

Te-127 

Te-127m 

Te-129 

Te-129m 

Te-131m 

Te-132 

I-131 

I-132 

Cs-134 

Cs-136c 

Cs-137c 

Ba-140 

La-140 

Ce-141 

Dose conversion factorh 

(mrem per pCi!m2

) 

Radioactive decay Radioactive 

plus weathering decay only 

1.2E-7 1.4E-7 

4.2E-7 5.6E-7 

6.3E-5 6.7E-5 

1.5E-4 1.6E-4 

1.2E-5 1.7E-5 

2.2E-4 2.9E-4 

1.6E-4 1.9E-4 

7.2E-7 8.3E-7 

6.1E-7 7.4E-7 

4.4E-6 4.6E-6 

7.7E-9 7.7E-9 

6.8E-7 7.8E-7 

6.4E-7 8.7E-7 

6.5E-8 6.6E-8 

3.4E-6 3.4E-6 

1.0E-6 1.0E-6 

7.8E-7 9.5E-7 

5.0E-7 5.0E-7 

3.4E-5 3.6E-5 

2.9E-7 2.9E-7 

5.4E-9 5.4E-9 

8.5E-7 8.7E-7 

5.0E-5 5.0E-5 

2.6E-5 3.3E-5 

1.4E-7 3.7E-7 

2.1E-5 2.9E-5 

9.1E-6 9.6E-6 

1.2E-5 1.3E-5 

6.6E-7 7.1E-7 

7-18 

Table 7-5, Continued 

Radionuclide 

Ce-143 

Ce-144c 

Pr-143 

Nd-147 

Np-239 

Am-241 

aBased on data from reference AR-89. 

Dose conversion factorsb 

(mrem per pCi/m2

) 

Radioactive decay 

plus weathering 

2.3E-6 

8.7E-7 

1.3E-5 

4.3E-6 

3.4E-8 

4.6E-8 

Radioactive 

decay only 

2.3E-6 

l.lE-6 

1.4E-5 

4.5E-6 

3.4E-8· 

6.4E-8 

bDose equivalent integrated for a one-year exposure at one meter height plus the estimated dose to 

the skin from materials deposited on the skin as a result of being in the contaminated area. 

ccontributions from short-lived (one hour or less) decay products are included in dose factors for the. 

parent radionuclides (i.e., Rh-106, Ba-136, Ba-137, and Pr-144). 

limits (EP-87). Dose projections for 

individuals should take into account 

the maximum expected duration of 

exposure. 

Persons working in areas inside the 

restricted zone should operate under 

the controlled conditions normally 

established for occupational exposure 

(EP-87). 

7.6 Surface Contamination Control 

Areas under the plume can be 

expected to contain deposited 

radioactive materials if aerosols or 

particulate materials were released 

during the incident. In extreme cases; 

individuals and eq\]ipment may be 

highly contaminated, and screening 

stations will be required for emergency 

monitoring and decontamination of 

individuals and to evaluate the need 

for medical evaluation. Equipment 

should be checked at this point and 

decontaminated as necessary to avoid 

the spread of contamination to other · 

locations. This screening service would . 

be required for only a few days · 

following plume passage until all such 

7-19 

persons have been evacuated or 

relocated. 

After the restricted zone is 

established, based on the PAGs for 

relocation, adults may· reenter the 

restricted zone under controlled 

conditions in accordance with 

occupational exposure standards. 

Monitoring stations will be required 

along roadways to control surface 

contamination at exits from the 

restricted zone. Because of the 

possibly high background radiation 

levels at control points near exits, 

significant levels of surface 

contamination on persons and 

equipment may be undetectable at

these locations. Therefore, additional 

monitoring and decontamination 

stations may be needed at nearby low 

background locations.

Decontamination and other measures 

should be implemented to maintain low 

exposure rates at monitoring stations. 

7 .6.1 Considerations and Constraints 

Surface contamination limits to 

control routine operations at nuclear 

facilities and to transport radioactive 

material are generally set at levels 

lower than are practical for situations 

involving high-level, widespread 

contamination of the environment. 

The principal exposure pathways for 

loose surface contamination on persons, 

clothing, and equipment are (a) 

internal doses from ingestion by direct 

transfer, (b) internal doses from 

inhalation ofresuspendedmaterials, (c) 

beta dose to skin from contaminated 

skin or clothing or from nearby 

surfaces, and (d) dose to the whole 

body from external gamma radiation. 

Because of the difficulties in 

predicting the destiny of uncontrolled 

surface contamination, a contaminated 

individual or item should not be 

. released to an unrestricted area unless 

contamination levels are low enough 

that they produce only a small 

increment of risk to health (e.g., less 

than 20 percent), compared to the risk 

to health from the principle exposure 

pathway (e.g., whole body gamma dose) 

in areas immediately outside the 

restricted zone. On the other hand, a 

level of contamination comparable to 

that existing on surfaces immediately 

outside the restricted zone may be 

acceptable on materials leaving the 

restricted zone. Otherwise, persons 

and equipment occupying areas 

immediately outside the restricted zone 

would not meet the surface 

contamination limits. These two 

constraints are used to set permissible 

surface contamination limits. 

The contamination limit should 

also be influenced by the potential for 

the contamination to be ingested, 

inhaled, or transferred to other 

locations. Therefore, it is reasonable to 

establish lower limits for surfaces 

where contamination is loose than for 

surfaces where the contamination is 

fixed except for skin. The expected 

period of fixed contamination .on skin 

would be longer so a lower limit would 

be justified. 

For routine (nonincident) 

situations, measurement of gross 

7-20 

beta-gamma surface contamination 

levels is commonly performed with a 

thin-window geiger counter (such as a 

CDV-700). Since beta-gamma 

measurements made with such field 

instruments cannot be interpreted in 

terms of dose or exposure rate, the 

guidance set forth below is related to 

the background radiation level in the 

area where the measurement is being 

made. Supplementary levels are 

provided for gamma ·exposure rates 

measured with the beta shield closed. 

Guidance levels expressed in this form 

should be easily detectable and should 

satisfy the above considerations. 

Corresponding or lower levels 

expressed in units related to 

instrument designations may be 

adopted for convenience or for ALARA 

determinations. Smears may also be 

used to detect loose surface 

contamination at very low levels. 

However, they are not considered 

necessary for emergency response and, 

therefore, such guidance is not 

provided. 

7.6.2 Numerical Relationships 

As discussed in Section 7.3.1, a 

relationship can be established between 

projected first year doses and 

instantaneous gamma exposure ·rates 

from properly characterized surface 

contamination. Based on assumed 

radiological characteristics of releases 

from fuel melt accidents, gamma 

exposure rates in areas where the 

projected dose is equal to the relocation 

PAG of 2 rem in the first year may be 

in the range of 2 to 5 mR/h during the 

first few days following the deposition 

from a type . SST-2 accident (See 

Section E.1.2). (This relationship must 

be determined for each specific release 

mixture.) Based on relationships in 

reference (D0-88) and a mixture of 

radionuclides expected to be typical of 

an SST-2 type accident, surface 

contamination levels of 2x108 pCilm2 

would correspond approximately to a 

gamma exposure rate ·of 1 mR/h at 1 

meter height. · 

7.6.3 Recommended Surface 

Contamination. Limits 

Surface contamination must be 

controlled both before and after 

relocation P AGs are implemented. 

Therefore, this section deals with the 

control of· surface contamination on 

persons and equipment being protected 

during both the early and intermediate 

phases of a nuClear incident. 

For emergency situations, the 

following general guidance regarding 

surface contamination is recommended: 

1. Do not· delay urgent medical care 

for decontamination efforts or for timeconsuming protection of attendants. 

2. Do not waste effort trying to 

contain contaminated·wash water. 

3. Do not allow monitoring and 

decontamination to delay evacuation 

from high or potentially high exposure 

rate areas. · 

4. (Optional provision, for use only if 

a major contaminating event occurs, 

and rapid early screening is needed.) 

7-21 

After plume passage, it may be 

necessary to establish emergency 

contamination screening stations in 

areas not qualifYing as low background 

areas. Such areas should be less than 

5 mRih gamma exposure rate. These 

screening stations should be used only 

during the early phase and for major 

releases ofparticulate materials to the 

atmosphere to monitor persons 

emerging from possible high exposure 

areas, provide simple (rapid) 

decontamination if needed, and make 

decisions on whether to send them for 

special care or to a monitoring and 

decontamination station in a lower 

background area. Table 7-6 provides 

guidance on surface contamination 

levels for use if such centers are 

needed. 

5. Establish monitoring and personnel 

decontamination (bathing) facilities at 

evacuation centers or other locations in 

low background areas Gess than 

0.1 m.Rih). Encourage evacuated 

persons who were exposed in areas 

where inhalation of particulate 

materials would have warranted 

evacuation to bathe, change clothes, 

wash clothes, and wash other exposed 

surfaces such as cars and trucks and 

their contents and then report to these 

centers for monitoring. Table 7-7 

provides surface contamination 

guidance for use at these centers. 

These screening levels are examples 

derived primarily on the basis of easily 

measurable concentrations using 

portable instruments. 

6. After the restricted zone is 

established, set up monitoring and 

decontamination stations at exits from 

the restricted zone. Because of the 

probably high background radiation 

levels. at these locations, low levels of 

contamination may be undetectable. If 

contamination levels are undetectable, 

then they probably do not exceed those 

in some unrestricted areas occupied by 

the exposed population and no 

decontamination is required. 

Nevertheless, these individuals should 

be advised to bathe and change clothes 

at their first opportunity and certainly 

within the next 24 hours. If, after 

decontamination atthe boundary ofthe 

restricted zone station, persons still 

exceed the limits for this station, they 

should be sent for further 

decontamination orfor medical or other 

special attention. A£ an alternative to 

decontamination, contaminated items 

other than persons or animals may be 

retained in the restricted zone for 

radioactive decay. 

7. Establish auxiliary monitoring and 

decontamination stations in low 

background areas (background less 

than 0.1 m.Rih). These stations should 

be used to achieve ALARA surface 

contamination levels. Table 7-7 

provides surface contamination 

screening levels for use at those 

stations. 

7-22 

Table 7-6 Recommended Surface Contamination Screening Levels for Emergency 

Screening of Persons and Other Surfaces at Screening or Monitoring 

Stations in High Background Radiation Areas (0.1 mRih to 5 mRih 

Gamma Exposure)a 

Condition 

Before 

decontamination 

After 

decontamination 

Geiger-counter shieldedwindow reading 

<2X bkgd and <0.5 mRih 

above background 

>2X bkgd or >0.5 mR1h 

above background 

<2X bkgd and <0.5 mRih 

above background 

>2X bkgd or >0.5 mRih 

above background 

Recommended action 

Unconditional 

release 

Decontaminate 

Equipment may be 

stored or disposed 

of as appropriate. 

Unconditional 

release 

Continue to 

decontaminate or 

refer to low background monitoring 

and d-con station. 

Equipment may also 

be stored for 

decay or disposed 

of as appropriate. 

aMonitoring stations in such high exposure rate areas are for use only during the early phase of an 

incident involving major atmospheric releases of particulates. Otherwise use Table 7-7. 
Table 7-7 	 Recommended Surface Contamination Screening Levels for Persons 

and Other Surfaces at Monitoring Stations in Low Background 

Radiation Areas ( <0.1 mRih Gamma Exposure Rate) 

Condition 

Before decontamination 

After simpleh 

decontamination effort 

After fullc 

decontamination effort 

After additional 

full decontamination effort 

Geiger-counter 


thin windoW" reading 


<2Xbkgd 

>2Xbkgd 

<2Xbkgd 

>2Xbkgd 

<2Xbkgd 

>2Xbkgd 

<0.5 mR/hd 

<2Xbkgd 

>2Xbkgd 

Recommended action 

Unconditional release 

Decontaminate 

Unconditional release 

Full decontamination 

Unconditional release 

Continue to decontaminate 

persons 

Release animals and 

equipment 

Unconditional full release 

Send persons for special 

evaluation 

Release animals and 

equipment 

Refer, or use informed 

judgment on 

further control of animals 

and equipment 

"Window thickness of approximately 30 mg/cm2 is acceptable. Recommended limits for open 

window readings are expressed as twice the existing background (including backgronnd) in the 

area where measurements are being made. Corresponding levels, expressed in nnits related to 

instrument designations, may be adopted for convenience. Levels higher than twice backgronnd 

7-24 

References 

AR-89 Aaberg, Rosanne. Evaluation of Skin 

and Ingestion Exposure Pathways. EPA 

520/1-89-016, U.S. Environmental Protection 

Agency, Washington (1989). 

D0-88 U.S. Department of Energy. External 

Dose-Rate Conversion Factors for 

Calculation of Dose to the Public. 

DOE/EH-0070, U.S. Department of Energy, 

Washington (1988). 

EP-87 U.S. Environmental Protection 

Agency. Radiation Protection Guidance to 

Federal Agencies for Occupational Exposure. 

Federal Register, 52, 2822; January, 1987. 

EP-88 U.S. Environmental Protection 

Agency. Limiting Values of Radionuclide 

Intake and Air Concentration and Dose 

Conversion Factors for Inhalation, 

Submersion, and Ingestion. EPA 

520/1-88-020, U.S. Environmental Protection 

Agency, Washington (1988). 

FE-85 Federal Emergency Management 

Agency. Federal Radiological Emergency 

Response Plan (FRERP). Federal Register, 

50, 46542; November 8, 1985. 

NR-75 U.S. Nuclear Regulatory 

Commission. Reactor Safety Study. ArJ. 

Assessment of Accident Risks in U. S. 

Commercial Nuclear Power Plants. 

WASH-1400, NUREG-75/014, U.S. Nuclear 

Regulatory Commission, Washington, (1975). 

(footnote continued) 

(not to exceed the meter reading corresponding to 0.1 mR/h) may be used to speed the monitoring 


of evacuees in very low background areas. 


b Flushing with water and wiping is an example of a simple decontamination effort. 


e Washing or scrubbi:qg with soap or solvent followed by flushing is an example of a full 


decontamination effort. 


d Closed shield reading including background. 


7-25 


CHAPTERS 

Radiation Protection Guides for the Late Phase (Recovery) 

(Reserved) 

8-1 


APPENDIX A 

Glossary 

APPENDIX A 


Glossary 

The following definitions apply 

specifically to terms used in this 

manual. 

Acute health effects: Prompt radiation 

effects (those that would be observable 

within a short period oftime) for which 

the severity of the effect varies with 

the dose, and for which a practical 

threshold exist. 

Ablation: The functional destruction of 

an organ through surgery or exposure 

to large doses of radiation. 

Buffer zone: An expanded portion of 

the restricted zone selected for 

temporary radiation protection controls 

until the stability ofradioactivity levels 

in the area is confirmed. 

Cloudshine: Gamma radiation from 

radioactive materials in an airbome 

plume. 

Committed dose: The radiation dose 

due to radionuclides in the body over a 

50-year period following their 

inhalation or ingestion. 

Delayed health effects: Radiation 

effects which are manifested long after 

the relevant exposure. The vast 

majority are stochastic, that is, the 

severity is independent of dose and the 

probability is assumed to be 

proportional to the dose, without 

threshold. 

Derived response level (DRL): A level 

of radioactivity in an environmental 

.medium that would be expected to 

produce a dose equal to its 

corresponding Protective Action Guide. 

Dose conversion factor: Any factor that 

is used to change an environmental 

measurement to dose in the units of 

concem. 

Dose equivalent: The product of the 

absorbed dose in rad, a quality factor 

related to the biological effectiveness of 

the radiation involved and any other 

modifying factors. 

Effective dose equivalent: The sum of 

the products of the dose equivalent to 

each organ and a weighting factor, 

where the weighting factor is the ratio 

of the risk of mortality from delayed 

health effects arising from irradiation 

of a particular organ or tissue to the 

total risk of mortality from delayed 

health effects when the whole body is 

irradiated uniformly to the same dose. 

Evacuation: The urgent removal of 

people from an area to avoid or reduce 

high-level, short-termexposure, usually 

from the plume or from deposited 

activity. Evacuation may be a 

A-1 

preemptive action taken in response to 

a facility condition rather than , an 

actual release. 

Genetic effect: An effect in a 

descendant resulting , from the 

modification, of genetic material i~ a 

parent. 

Groundshine: Gamma radiatio~ from 

radioactive materials deposited on the 

ground. 

Incident phase: Thls , guidance 

distinguishes three pl1ases of an 

incident (or accident): (a) early phase, 

(b) intermediate phase, and (c) late 

phase. 

(a) Early phase: The period at the 

beginning of a nuclear incident when 

immediate decisions for effective use of 

protective actions are required, and 

must be based primarily on predictions 

of radiological conditions in the 

environment. This phase may last 

from hours to days. For the purpose of 

dose projection, it is assumed to last for 

four days. 

(b) Intermediate phase: The period 

beginning after the incident source and 

releases have been brought under 

control and reliable environmental 

measurements are available for use as 

a basis for decisions on additional 

protective actions and extending until 

these protective actions are terminated. 

This phase may overlap the early and 

late phases and may last from weeks to 

many months. For the purpose of dose 

projection, it is assumed to last for one 

year. 

(c) Late phase: The period 

beginning when recovery action 

designed to reduce radiation levels in 

the environment to permanently 

acceptable levels are commenced, and 

ending when all recovery actions have 

been completed. This period may 

extend from months to years (also 

referred to as the recovery phase). 

Linear Energy Transfer (LET): A 

measure of the ability of biological 

material to absorb ionizing radiation; 

specifically, for charged particles 

traversing a medium, the energy lost 

per unit length of path as a result of 

those collisions with elections in which 

the energy loss is less than a specified 

maximum value. A similar quantity 

may be defined for photons. 

Nuclear incident: An event or series of 

events, either deliberate or accidental, 

leading to the release, or potential 

release, into the environment of 

radioactive materials in sufficient 

quantity to warrant consideration of 

protective actions. 

Prodromal effects: The forewarning 

symptoms of more serious health 

effects. 

Projected dose: Future dose calculated 

for a specified time period on the basis 

of estimated or measured initial 

concentrations of radionuclides or 

exposure rates and in the absence of 

protective actions. 

Protective action: An activity 

conducted in response to an incident or 

potential incident to avoid or reduce 

radiation dose to members ofthe public 

A-2 

(sometimes called a protective 

measure). 

Protective Action Guide (PAG): The 

projected dose to reference man, or 

other defined individual, from an 

accidental release of radioactive 

material at which a specific protective 

action to reduce or avoid that dose is 

warranted. 

Recovery: The process of reducing 

radiation exposure rates and 

concentrations of radioactive material 

in the environment to levels acceptable 

for unconditional occupancy or use. 

Reentry: Temporary entry into a 

restricted· zone under controlled 

conditions. 

Relocation: The removal or continued 

exclusion of people· (households) from 

contaminated areas to avoid chronic 

radiation exposure. 

Restricted zone: An area with 

controlled access from which the 

population has been relocated. 

Return: The reoccupation of areas 

cleared for unrestricted residence or 

use. 

Sheltering: The use of a structure for 

radiation protection from an airborne 

plume and/or deposited radioactive 

materials. 

Short-lived daughters: Radioactive 

progeny of radioactive isotopes that 

have half-lives on the order of a few 

hours or less. 

Weathering factor: The fraction of 

radioactivity remaining after being 

affected by average weather conditions 

for a specified period of time. 

Weighting factor: A factor chosen to 

approximate the ratio of the risk of 

fatal cancer from the irradiation of a 

specific tissue to the risk when the 

whole body is irradiated uniformly to 

the same dose. 

Whole body dose: Dose resulting from 

uniform exposure of the entire body to 

either internal or external sources of 

radiation. 

A-3 


APPENDIXB 


Risks To Health From Radiation Doses 


That May Result From 


Nuclear Incidents 


Contents 

Page 

B.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . B-1 


B.1.1 Units of Dose . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . B-1 


B.1.2 Principles for Establishing Protective 


Action Guides .................................... B-2 


B.2 Acute Effects . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . B-3 


B.2.1 Review of Acute Effects .............................. B-3 


B.2.1.1 The Median Dose for Lethality ................ B-4 


B.2.1.2 Variation of Response for Lethality . . . . . . . . . . . . B-5 


B.2.1.3 Estimated Lethality vs Dose for Man ............ B-7 


B.2.1.4 Threshold Dose Levels for Acute Effects . . . . . . . . . B-10 


B.2.1.5 Acute Effects in the Thyroid .................. B-12 


B.2.1.6 Acute Effects in the Skin .....................B-12 


B.2.1.7 Clinical Pathophysiological Effects . . . . . . . . . . . . . B-12 


B.2.2 Summary and Conclusions Regarding Acute Effects ........ B-17 


B.3 Mental Retardation ....................................... , B-17 


B.4 Delayed Health Effects . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . B-18 


B.4.1 Cancer . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . B-18 


B.4.1.1 Thyroid . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . B-20 


B.4.1.2 Skin .................................... B-21 


B.4.1.3 Fetus . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . B-21 


B.4.1.4 Age Dependence of Doses . . . . . . . . . . . . . . . . . . . . B-22 


B.4.2 Genetic Risk ........................ ~ . . . . . . . . . . . . . B-23 


B.4.3 Summary of Risks of Delayed Effects ................... B-23 


B.4.4 Risks Associated with Other Radiation Standards .......... B-23 


References .................................................. B-25 


111 
Figures 

Page 


B-1 Acute Health Effects as a Function ofWhole Body Dose ............ B-9 


Tables 

B-1 Radiation Doses Causing Acute Injury to Organs ................ B-14 


B-2 Acute Radiation Exposure as a Function of Rad 


Equivalent Therapy Units (rets) .............................. B-15 


B-3 Radiation Exposure to Organs Estimated to Cause 


Clinical Pathophysiological Effects Within 5 Years 


to 0.1 Percent of the Exposed Population ..................... B-16 


B-4 Average Risk of D~layed Health Effects in a Population . . . . . . . . . . . . B-24 


IV 

APPENDIXB 


Risks To Health From Radiation Doses 


That May Result From 


Nuclear Incidents 


B.l Introduction 

This appendix reviews the risks 

from radiation that form the basis for 

the choice of Protective Action Guides 

(PAGs) for the response to a nuclear 

incident, as well as the choice oflimits 

for occupational exposure during a 

nuclear incident. 

B.l.l Units of Dose 

The objective of protective action 

is to reduce the risk to health from 

exposure to radiation. Ideally, one 

would like to assure the same level of 

protection for each member of the 

population. However, protective 

actions cannot take into account 

individual variations 1n 

radiosensitivity, since these are not 

known. Therefore, these PAGs are 

based on assumed average values of 

risk. We further assume that these 

risks are proportional to the dose, for 

any level of dose below the threshold 

for acute effects (see Section B.2.). 

The dose from exposure to 

radioactive materials may be delivered 

during the period of environmental 

exposure only (e.g., extemal gamma 

radiation), or over a longer period (e.g., 

inhaled radionuclides which deposit in 

body organs). In the latter case, dose 

is delivered not only at the time of 

intake from the environment, but 

continues until all of the radioactive 

material has decayed or is eliminated 

from the body. Because ofthe variable 

time over which such doses may be 

delivered, the P AGs are expressed in 

terms of a quantity called the 

"committed dose." Conceptually, 

committed dose is the dose delivered 

over an individual's remaining lifetime 

following an intake of radioactive 

material. However, due to differences 

in physiology and remaining years of 

life, the committed dose to a child from 

intemal radioactivity may differ from 

that to an adult. For simplicity, adult 

physiology and a remaining lifetime of 

50 years are assumed for the purpose 

of calculating committed doses. 

Anotherimportant considerationis 

that different parts of the body are at 

different risk from the same dose. 

Since the objective ofprotective actions 

is the reduction of health risk, it is 

appropriate to use a quantity called 

"effective dose." Effective dose is the 

sum ofthe products ofthe dose to each 

organ or tissue of the body and a 

weighting factor representing the 

relative risk. These weighting factors 

(IC-77) are chosen as the ratio of 

mortality (from delayed health effects) 

from irradiation ofparticular organs or 

tissues to the total risk of such 

B-1 

mortality when the whole body is 

irradiated uniformly at the same dose. 

Finally, doses from different types 

of radiation (e.g. alpha, beta, gamma, 

and neutron radiation) have different 

biological effectiveness. These 

differences are customarily accounted 

for, for purposes ofradiation protection, 

by multiplicative modifying factors. A 

dose modified by these factors is 

designated the "dose equivalent." The 

P AGs are therefore expressed in terms 

of committed effective dose equivalent. 

The PAGs are augmented by limits for 

a few specific organs (skin and thyroid) 

which exhibitspecial sensitivity. These 

are expressed in terms of committed 

dose equivalent (rem). In the process 

of developing PAG values, it is 

necessary to evaluate the threshold 

dose levels for acute health effects. 

These levels are generally expressed in 

terms of absorbed dose (rad) to the 

whole body from short term (one month 

or less) exposure. Other units 

(Roentgens, rem, and rets) are also 

used in information cited from various 

references. They are all approximately 

numerically equivalent to rads in terms 

of the risk of acute health effects from 

beta and gamma radiation. 

P AGs are intended to apply to all 

individuals in a population other than 

workers performing emergency 

services. However, there may be 

identifiable groups that have different 

average sensitivity to radiation or, 

because of their living situation, will 

receive higher or lower doses. In 

addition, some groups may be · at 

greater risk from taking a given 

protective action. These factors are 

separately considered, when it is 

appropriate; in establishing values for 

the PAGs. 

B.1.2 Principles for Establishing 

Protective Action Guides 

The following four principles 

provide the basis for establishing 

values for Protective Action Guides: 

1. Acute effects on health (those that 

would be observable within a short 

period of time and which have a dose 

threshold below which they are not 

likely to occur) should be avoided. 

2. The risk of delayed effects on health 

(primarily cancer and genetic effects, 

for which linear nonthreshold 

relationships to dose are assumed) 

should not exceed upper bounds that 

are judged to be adequately protective 

of public health, under emergency 

conditions, and are reasonably 

achievable. 

3. PAGs should not be higher than 

justified on the basis of optimization of 

cost and the collective risk of effects on 

health. That is, any reduction of risk 

to public health achievable at 

acceptable cost should be carried out. 

4. Regardless of the above principles, 

the risk to health from a protective 

action should not itself exceed the risk 

to health from the dose that would be 

avoided. 

With the exception of the second, 

these principles are similar to those set 

forth by the International Commission 

B-2 

on Radiological Protection (IC-84b) as 

the basis for establishing intervention 

levels for nuclear accidents. We 

examine, below, the basis for 

estimating effects on health for use in 

applying the first two of these 

principles. 

B.2 Acute Effects 

This section provides information 

relevant to the first principle: 

avoidance of acute · effects on health 

from radiation. 

Acute radiation health effects are 

those clinically observable effects on 

health which are manifested within 

two or three months after exposure. 

Their severity depends on the amount 

of radiation dose that is received. 

Acute effects do not occur unless the 

dose is relatively large, and there is 

generally a level ofdose (i.e., threshold) 

below which an effect is not expected to 

occur. Acute effects may be classified 

as severe or nonsevere clinical 

pathophysiological effects. Severe 

pathophysiological effects are those 

which have clinically observable 

symptoms and may lead to serious 

disease and death. Other pathophysiological effects, such as 

hematologic deficiencies, temporary 

infertility, and chromosome changes, 

are not considered to be severe, but 

may be detrimental in varying degrees. 

Some pathophysiological effects, such 

as erythema, nonmalignant skin 

damage, loss of appetite, nausea, 

fatigue, and diarrhea, when associated 

with whole body gamma or neutron 

exposure, are prodromal (forewarning 

of more serious pathophysiological 

effects, including death). 

B.2.1 Review of Acute Effects 

This section summarizes the 

results of a literature survey of reports 

of acute effects from short-term 

(arbitrarily taken as received in one 

month or less) radiation exposure in 

some detail. Many reports of observed 

effects at lower doses differ, and some 

are contradictory; however, most have 

been included for the sake of 

completeness. The results of the 

detailed review described in this 

Section are summarized in Section 

B.2.2. 

The biological response to the 

rapid delivery of large radiation doses 

to man has been studied since the end 

of World War II. Dose-response 

relationships for prodromal 

(forewarning) symptoms and for death 

within 60 days have been developed 

from data on the Japanese A-bomb 

survivors, Marshall Island natives 

exposed to fallout, and . patients 

undergoing radiotherapy. . This work 

has been supplemented by a number of 

animal studies under controlled 

conditions. 

The animal studies, usually using 

lethality as the end point, show that 

many factors can influence the degree 

of response. The rate at which the 

dose is delivered can affect the median 

lethal dose (LD50) in many species, 

particularly. at dose rates less than 

5 R/min (PA-68a; BA-68). However, in 

primates there is less than a 50 

B-3 

percent increase in the LD50 as dose 

rates are decreased from 50 R/min to 

about 0.01 R/min (PA-68a). There is 

good evidence of species specificity 

(PA-68a; B0-69). The LD50 ranges 

from about 100 rad for burros to over 

1000 rad for lagomorphs (e.g., rabbits). 

Response is modulated by: age (CA-68), 

extent of shielding (partial body 

irradiation) (B0-65), radiation quality 

(PA-68a; B0-69), diet, and state of 

health (CA-68). 

While animal studies provide 

support and supplemental information, 

they cannot be used to infer the 

response for man. This lack of 

comparability ofman and animals had 

already been noted by a review 

committee for the National Academy of 

Sciences as early as 1956, in 

considering the length of time over 

which acute effects might be 

expressed (NA-56): "Thus, an LD50, 

30-day consideration is inadequate to 

characterize the acute lethal dose 

response ofman, and an LD50, 60 days 

would be preferable."1 

Several estimates of the levels at 

which acute effects of radiation occur 

in man have been published. For 

example, an early estimate of the 

~e committee (known as the BEAR 

Committee) also noted "The reservation must 

be made here that the exposed Japanese 

population was heterogeneous with respect to 

age, sex, physical condition and degree of 

added trauma from burns or blast. The extent 

to which these factors affected the · survival 

time has not been determined. In studies on 

laboratory animals the converse is 

true--homogeneous populations are studied" 

(NA-56, p.l-6). 

dose-response curves for prodromal 

(forewarning) symptoms and for 

lethality was made in the first edition 

of "The Effects of Nuclear Weapons" 

(1957) (GL-57), and a more recent and 

well documented estimate is given in a 

NASA publication, "Radiobiological 

Factors in Manned Space Flight" 

(LA-67). 

B.2.1.1 The Median Dose for Lethality 

The radiation dose that would 

cause 50 percent mortality in 60 days 

was estimated as 450 Roentgens in 

early reports (NA-56; GL-57; RD-51). 

The National Commission onRadiation 

Protection and Measurements (NCRP) 

calculated that this would correspond 

to a midline absorbed dose of 315 rad 

(NC-74). The ratio of 315 rad to 450 

Roentgens is 0.70, which is about the 

estimated ratio of the active marrow 

dose, in rads, to the tissue kerma in 

air, in rads (Iill-80). The BEAR 

Committee noted that the customary 

reference to LD50 in animal studies, as 

if it were a specific property, 

independent of age, was not justifiable 

(NA-56): "...it is evident, now, that 

the susceptibility of a whole population 

is not describable by a single LD50• 

The published values are usually 

obtained for young adults and are 

therefore maximal or nearly maximal 

for the strain. In attempts to estimate 

LD50 in man, this age dependence 

should be taken into consideration" 

(NA-56, pp.4-5). They observed that 

the LD50 approximately doubled as rats 

went from neonates to young adults 

and then decreased as the animals 

aged further. Finally, the BEAR 

B-4 

Committee concluded: "The situation is 

complex, and it became evident that it 

is not possible to extrapolate with 

confidence from one condition of 

radiation exposure to another, or from 

animal data to man" (NA-56, p.I-8). 

Nevertheless, results from animal 

studies can aid in interpreting the 

human data that are available. 

The NCRP suggested the LD50160 

might be 10 to 20 percent lower for the 

old, very young, or sick, and somewhat 

greater for healthy adults . of 

intermediate age (RD-51). Other 

estimates of adult LD50160 have ranged 

from about 300 rad to 243 + 22 rad. 

These lower estimates are apparently 

based on a ratio of air to tissue dose 

similar to those calculated for midline 

organs in the body; 0.54 to 0.66 (KE-80; 

OB-76; K0-81). 

A NASA panel examined all 

patient and accident studies, tried to 

remove confounding factors, and 

concluded, "On this basis, it may be 

assumed that the LD50 value of286 rad 

obtained by a normal fit to the patient 

data is the preferred value for healthy 

man.. (LA-67). 

An LD50160 of 286 25 rad 

(standard deviation) midline absorbed 

dose and an absorbed dose/air dose 

ratio of0.66, suggested by the National 

Academy of Science (LA-67), is 

probably a reasonable value for healthy 

males. In the absence of more 

complete information, we assume that 

a value of 300 rad + 30 rad is a 

reasonable reflection of current 

uncertainties for average members of 

the population. 

B.2.1.2 Variation of Response for 

Lethality 

Uncertainty in the dose-response 

function for acute effects has been 

expressed in various ways. The slope 

. ofthe estimated dose-response function 

has most commonly been estimated on 

the basis of the percent difference in 

the LD50 and the LD15•

9 or LD84.1 (one 

standard deviation from the LD50), as 

was done by NASA (GL-57). These and 

other parameters derived in a similar 

manner describe the uncertainty in the 

central risk estimate for the 

dose-response function. 

Another means is to use an 

estimate ofupper and lower bounds for 

the central risk estimate, e.g., the 95 

percent fiducial limits. At any given 

response point on the dose-response 

function, for example, the LD10, the 

dose causing that response has a 

95 percent probability oflying between 

the lower and upper bounds of the 

95 percent fiducial limit for that point. 

To estimate this value, probit analyses 

were run for each species using data in 

published reports (K0-81; TA-71). This 

provided estimates for each species for 

comparability analyses. The 95 percent 

fiducial limits at the LD50 response for 

LD50130 studies averaged +9 percent 

(range -9 to +26 percent) and for LD50160 

studies +17 percent (range -20 to +45 

percent). At the LD15 response, values 

were + 16 percent (range -12 to +50 

percent) for LD15130 data and 

+26 percent (range -20 to +65 percent) 

for LD15160 data. For the LD85 response, 

values were +17 percent (range -36 to 

+36 percent) for the LD85180 data and 

B-5 

+24 percent (range -46 to +31 percent) 

for LD85160 data. 

The differences in the magnitude 

of the fiducial limits are a function of 

the differences in age, sex, radiation 

quality, degree of homogeneity of the 

experimental animals, husbandry, and 

other factors. The estimates show that 

the fiducial limits, expressed as a 

percent ofthe dose at any response, get 

greater the farther from the LD50 the 

estimate is made. For the purpose of 

estimating fiducial limits for humans, 

the 95 percent fiducial limits will be 

considered to be LD15 + 15 percent, LD50 

+10 percent, and LD85 ±15 percent. 

Beyond these response levels, the 

fiducial limits are too uncertain and 

should not be used. 

Ifthe median lethal dose, LD50160, 

is taken as 300 +30 rad midline 

absorbed dose, the response to higher 

and lower doses depends on the degree 

of biological variation in the exposed 

population. The NASA panel decided 

the wide variation in the sensitivity of 

patients was a reflection of the 

heterogeneity of the sample; and that 

the variation in sensitivity, the slope of 

the central estimate of the response 

function, would be stated in the form of 

one standard deviation calculated as 

58 percent of the LD50• They further 

decided the deviation in the patients 

(58 percent) was too great, and the 

standard deviation for "normal" man 

should be closer to that of dogs and 

monkeys (18 percent) (LA-67). (The 

rationale for selecting these species 

was not given.) 

Jones attempted to evaluate the 

hematologic syndrome from 

mammalian lethality studies using the 

ratio of dose to LD50 dose as an 

indicator of the steepness of the slope 

of the dose-response function (J0-81). 

However, he evaluated LD50 studies 

only of species having a rather steep 

slope, i.e., dogs, monkeys, mice, and 

swine. He also looked at several 

different statistical models for 

dose-response functions and pointed 

out the problems caused by different 

models and assumptions, particularly 

in evaluating the tails of the 

dose-response function (less than LD10 

and greater than LD90). Jones 

recommended using a log-log model, 

which he felt provided a better fit at 

low doses (J0-81). 

Scott and Hahn also evaluated 

acute effects from mammalian 

lethality, butsuggested using a Weibull 

model (SC-80). One ofthe advantages 

ofthe Weibull model is that in addition 

to developing the dose-response 

function, it can also be used to develop 

hazard functions. These hazard 

functions, if developed using the same 

model, can be summed to find the joint 

hazard of several different types of 

exposure (SC-83). This would allow 

estimation of the total hazard from 

multiple organ exposures to different 

types of radiation. 

As mentioned earlier, the human 

median lethal dose is commonly 

·reported in terms of the LD50160• Most 

laboratory animal median lethal doses 

are reported in terms ofthe LD50130• In 

those cases where estimates of both 

LD50130 and LD50160 are available, i.e., 

B-6 

the burro (ST-69), the variation (that 

is, the slope ofthe dose-response curve) 

is greater in the LD50160 study than in 

the LD50130 study. Both the dog and the 

monkey data are for LD50180, and so are 

not appropriate for direct comparison 

to man. 

If an estimate of the deviation is , 

made for data from other studies and 

species, those where most of the 

fatalities occur within 30 days (like 

dogs and monkeys) have standard 

deviations of from around 20 percent 

[swine (x-ray) (ST-69), dogs (NA-66), 

hamsters (AI-65), primates (Macaca) 

(DA-65)] to 30 percent [swine (

6

°Co) 

(H0-68)]. Those in which most deaths 

occur in 60 days, like man, have 

deviations from around 20 percent 

[sheep (CH-64)] to 40 percent [goats 

(PA-68b), burros (TA-71)]. Nachtwey, 

et al. (NA-66) suggested the steepness 

of the slope of the exposure response 

curve depends on the inherent 

variability of the subjects exposed and 

any variation induced by uncontrolled 

factors, e.g., temperature, diurnal 

rhythm, and state of stimulation or 

arousal. So, while the slope of the 

response curve for the patients studied 

by the NASA panel may be 

unrealistically shallow for normal 

human populations, there is no reason 

to think it should be as steep as those 

for dogs and monkeys. 

The average deviation for those 

species (burros, sheep, and goats) for 

which the standard deviation of the 

LD50160 is available has been used as an 

estimator for man. The mean value is 

34 + 13 percent. This is only slightly 

greater than the average value for all 

physicallylarge animals (swine, burros, 

sheep, and goats), 32 + 12 percent. 

B.2.1.3 Estimated Lethality vs Dose 

forMan 

As noted in Section B.2.1.1, 

dose-response estimates vary for a 

number of reasons. Some factors 

affecting estimates for humans are: 

1. Age: 

Studies on rats indicate the LD50 is 

minimal for perinatal exposure, rises 

to maximum arouri.d puberty, and 

then decreases again with increasing 

age (CA-68). The perinatal LD50 is 

about one-third ofthat for the healthy 

young adult rats; that for the geriatric 

rat is about one-half of that for the 

young adult rat. 

2. Sex: 

Females are slightly more sensitive 

than males in most species (CA-68). 

3. Health: 

Animals in poor health are usually 

more sensitive than healthy animals 

(CA-68), unless elevated hematopoietic 

activity is occurring in healthy 

animals (SU-69). 

While these and other factors will 

affect the LD50160 and the response 

curve for man, there are no numerical 

data available. 

The variation in response at a 

given dose level increases as the 

population at risk becomes more 

heterogeneous and as the length of 

time over which mortality is expressed 

B-7 

increases. In general, larger species 

show greater variance and longer 

periods of expression than do small 

mammals, e.g., rodents. It is likely 

that the human population would show 

at least the same amount of variation 

as do the larger animals, i.e., a 

coefficient of variation of about 

one-third. 

The degree of variation exhibited 

in animal studies follows a Gaussian 

distribution as well as or better than a 

log normal distribution over that range 

ofmortality where there are reasonable 

statistics. We have assumed here that 

the functional form ofhw::nan response 

is Gaussian. Generally, sample sizes 

for extreme values (the upper and 

lower tails of the distribution) are too 

small to give meaningful results. 

Therefore, we have not projected risks 

for doses more than two standard 

deviations from the LD50160• We 

recognize that estimates of acute 

effects may not be reliable even beyond 

one standard deviation for a population 

containing persons of all ages and 

states of health. However, in spite of 

these uncertainties, previous estimates 

have been made of the acute effects 

caused by total body exposure to 

ionizing radiation as a function of the 

magnitude of the exposure (NC-71; 

LU-68; FA-73; NA-73). 

Given the large uncertainties in 

the available data, a median lethal 

dose value of about 300 rad at the 

midline, with a standard deviation of 

100 rad, may be assumed for planning 

purposes. Such risk estimates should 

be assumed to apply only in the 

interval from 5 percent to 95 percent 

fatality, as shown in Figure B-1. (See 

also section B.2.1.4.) 

Figure B-1 IS based on the 

following values: 

Dose (rad) Percent fatalities 

<140 none2 

140 5 

200 15 

300 50 

400 85 

460 95 

For moderately severe prodromal 

(forewarning) effects, we believe the 

dose at which the same percentage of 

exposed would show effects would be 

approximately half of that causing 

fatality. This yields the following 

results (see also Figure B-1): 

Dose (rad) Percent affected 

50 <2 

100 15 

150 50 

200 85 

250 98 

Although some incidence of 

prodromal effects has been observed at 

doses in the range of 15 to 20 rads in 

patients (LU-68) and in the 0 to 

10 rads range of dose in Japanese 

A-bomb survivors (SU-80a; GI-84), 

2tfue risk of fatality below 140 rad is not 

necessarily zero; rather, itis indeterminate and 

likely to remain so. This also applies to 

prodromal effects below 50 rad. 

B-8 

100 

90 

80 

70 

c 60 

w 

1­

0 

w 

u... 

u. 

<( 

50 

1­

z 

w 

0

a: 

w 

c.. 4 0 

30 

20 

10 

0 

I 	

j

'(

/ 

I 

a: 

~ Q I ~ (f) 

_, 

0

§ I


a: 

0 

f 

0 	 s/ 


fJ 


I 

), 

J / 

100 	 200 300 400 500 600 

WHOLE BODY ABSORBED DOSE (rad) 

FIGURE B-1. 	 ACUTE HEALTH EFFECTS AS A FUNCTION 

OF WHOLE BODY DOSE. 

B-9 
there is great uncertainty in 

interpreting the data. Patients may be 

abnormally sensitive, so that the 

dose-response function in patients may 

represent the lower bound ofdoses that 

would show a response in a healthy 

population (LU-67). The response of 

Japanese survivors in the low dose 

ranges is complicated by the blast and 

thermal exposure that occurred at the 

same time (SU-80b). For these 

reasons, care should be taken in 

applying estimates of prodromal 

effects. The prodomal dose-response 

function listed above is more likely to 

overestimate the proportion of persons 

affected than to underestimate it. 

These estimated ranges and effects 

are in agreement with estimates made 

for manned space flights (LA-67; 

LU-67), whichincluded consideration of 

the effect of abnormal physiology or 

sickness in the patients to which the 

data apply. Uncertainty in estimates 

of the biological effects of radiation 

exposure is great. It is probably due in 

part to variation in the health of 

individuals in exposed populations. 

These estimates assume a healthy 

young adult population and may not be 

a conservative estimate of risk for 

other population groups, such as 

children or the elderly. Lushbaugh, 

et al. (LU-68) found that prodromal 

effects probably occur in both healthy 

and ill persons in about the same dose 

range. However, Lushbaugh, et al. 

(LU-68) and NATO (NA-73) suggest 

that acute mortality in a population 

which is ill, injured, or in other ways 

debilitated will occur in 50 percent of 

that population at doses of200-250 rad 

in about 60 days (LD50160), in contrast to 

an LD50160 from doses of 220-310 rad for 

a healthy young adult population. 

Thus, the ill or injured are assumed to 

have an increased risk of acute 

mortality at high doses. 

The above estimates for LD50160 are 

also based on the assumption of 

minimal medical care following 

exposure. UNSCEAR (UN-88) 

estimates that the threshold for 

mortality would be about 50 percent 

higher in the presence ofmore intense 

medical care. 

B.2.1.4 Threshold Dose Levels for 

Acute Effects 

This section summarizes 

information available in the literature 

regarding thresholds for health effects. 

It also reviews actions that have been 

taken as a result ofradiation exposure 

to provide insight on dose levels at 

which actions to avoid dose may be 

appropriate. 

Some acute effects, such as cellular 

changes, may occur at low doses with 

no dose threshold. Most such effects 

have a rmmmum threshold of 

detectability; for example, five rad is 

about the lower limit of whole body 

dose which causes a cellular effect 

detectable by chromosome or other 

special analyses (NC-71; FA-73). This 

value is recommended by UNSCEAR as 

the starting point for biological 

dosimetry (UN-69). Purrott, et al. have 

reported a lower limit of detection of 

chromosome aberrations of 4 rad for 

x-rays and 10 rad for gamma rays 

(PU-75). 

B-10 

More recent advanced chromosome 

banding techniques permit detection of 

increased incidence of chromosome 

abnormalities from continuous 

exposure to systematically deposited 

radioisotopes or radioisotopes deposited 

in the lung at verylow levels, e.g., body 

burdens of 100 to 1200 pCi of 

plutonium-239 (BR-77). While the 

exact dose associated with such 

burdens is not known, it is probably on 

the order of 10 to 100 millirem per 

year. Lymphocytes exposed to 5 rem in 

vitro show severe metabolic dysfunction 

and interphase cell death (ST-64). The 

extent to which similar effects. occur 

after in vivo exposure is unknown. 

While chromosome abnormalities in 

circulating lymphocytes are reported to 

persist for long periods (UN-69), the 

significance of such abnormalities is 

not known (BR-77). 

Hug has suggested 5 rem as the 

lower limit of exposure which might 

produce acute effects (WH-65). Five 

rad is als.o in the low dose, short-term 

exposure range deimed by Cronkite 

and Haley, and is below the 10 rad 

which they thought would cause only a 

slight detectable physiological effect of 

unknown clinical significance (CR-71). 

Although the ICRP has suggested 

that annual doses of 15 rad would not 

impair the fertility of normal fertile 

men (IC-69), an acute dose of 15 rad 

causes "moderate" oligospermia 

(approximately 70 percent reduction in 

sperm count) which lasts for some 

months (LA-67). Popescu and 

Lancranjan reported alterations of 

spermatogenesis and impaired fertility 

in men exposed to from 500 millirad to 

3 rad per year for periods varying from 

2 to 22 years (P0-75). The shortest 

exposure period in which abnormal 

spermatogenesis was reported was 31 

to 41 . months (P0-75); at the highest 

dose rate reported (3 radla), this is a 

cumulative dose of 8 to 10 rem. While 

more study is required, these results 

suggest the need to restrict acute doses 

to below 10 rem to avoid this effect, 

because a given acute dose is 

anticipated to be more effective than 

the same cumulative dose given over a 

longer period of time (NA-56; UN-58). 

Many observations have indicated 

that doses of 10 rem or more to the 

pregnant woman are hazardous to the 

fetus. Mental retardation due to 

exposure of the fetus is discussed in 

Section B.3; this discussion is restricted 

to acute effects. The World Health 

Organization (WHO) indicates that 

there is no evidence of teratogenic 

effects from short term exposure ofthe 

fetus to a dose less than 10 rad during 

the early phase ofgestation, the period 

when the fetus is most sensitive to 

these effects (WH-84). 

A number of authorities have 

recommended that exposures of 10 

roentgens or higher be considered as an 

indication for carrying out induced 

abortion (HA-59, DE-70, BR-72, 

NE-76). Brent and Gorson also suggest 

that 10 rad is a "practical" threshold 

for induction of fetal abnormalities 

(BR-72). The Swedish Government 

Committee on Urban Siting of Nuclear 

Power Stations stated the situation as 

follows: "What we have called 

unconditional indication of abortion 

involves the exposure of pregnant 
women where radiation dose to the 

fetus is higher than 10 rad. When 

such doses are received in connection 

with medical treatment, it has hitherto 

been assumed that the probability of 

damage to the fetus is so high that an 

abortion is recommended. The 

probability for such injury is still 

moderate compared with the normal 

frequency of similar fetal injuries, and 

the probability is particularly reduced 

when the dose is received late in the 

pregnancy.. (NA-74). 

B.2.1.5 Acute Effects in the Thyroid 

Acute effects are produced in the 

thyroid by doses from radioiodine on 

the order of 3,000 to 100,000 rad. 

Ablation of the thyroid requires doses 

of 100,000 rad (BE-68). The thyroid 

can be rendered hypothyroid by doses 

of about 3,000 to 10,000 rad (IC-71). A 

thyroid dose from radioiodines of 1000 

rad in adults and 400 rad in children 

implies an associated whole body dose 

of about 1 rad due to radioiodines 

circulating in the blood. Following 

inhalation of 1811, the committed 

thyroid dose is about one radlp.Ci 

181 intake of 1 in adults. In the 

developing fetus, the thyroid dose 

ranges from one to six rad per p.Ci of 

181! entering the mother's body (IL-74). 

Although acute clinical effects are 

only observed at high doses, subclinical 

acute thyroid radiation effects may 

occur atlower doses (D0-72). Impaired 

thyroid capability may occur above a 

threshold of about 200 rad (D0-72). 

Effects of radiation exposure of the 

thyroid have been shown in animal 

experiments. Walinder and Sjoden 

found that doses in excess of 3,000 rad 

from 1811 caused noticeable depression 

of fetal and juvenile mouse thyroid 

development (WA-69). Moore and 

Calvin, working with the Chinese 

hamster, showed that an exposure as 

low as 10 roentgens (x-rays) would give 

rise to 3 percent aberrant cells when 

the thyroid was cultured (M0-68). 

While the direct relationship of these 

results to human effects is not certain, 

mammalian thyroid cells can be injured 

at exposures as low as 10 roentgens. 

B.2.1.6 Acute Effects in the Skin 

The first stage of skin reaction to 

radiation exposure is erythema 

(reddening) with a threshold of from 

300 to 800 rad. Acute exudative 

radiodermatitis results from doses of 

1,200 to 2,000 rad (WH-84). 

B.2.1.7 Clinical Pathophysiological 

Effects 

A large amount of anecdotal 

information is available on the injury 

of organ tissues by high doses of 

radiation. Acute injury to tissue 

includes swelling and vacuolation of 

the cells which make up the blood 

vessels, increased permeability of 

vessels to fluids so that exudates form, 

formation of fibrin clots and thrombi, 

fibrinoid thickening in the walls of 

blood vessels, and swelling and 

vacuolization of parenchymal cells. In 

summary, there is an initial exudative 

B-12 

reaction followed in time by fibrosis 

and sclerosis (WH-76, CA-76). 

Estimates of radiation doses 

necessary to cause severe tissue 

response in various organs are given in 

Table B-1. These tissue dose estimates 

are based on response to radiotherapy 

treatment, which is normally given on 

a fractionated dose basis, but also may 

be given as a continuous exposure. 

Therefore, these estimates must be 

adjusted to the equivalent single 

radiation dose for use in the present 

analysis. The formalism of Kirk, et al. 

(KI-71) is used to estimate the 

equivalent dose for a single acute 

exposure in rad-equivalent therapy 

units (rets: the dose calculated from 

the fractionated exposure which is 

equivalent to a single acute exposure 

for a specific biological endpoint.) 

Table B-2 lists acute exposure 

equivalents in rets for various organs. 

With the exception of bone marrow, 

the exposures required to cause 

5 percent injury within 5 years (TD 

5/5) in internal organs are in the range 

of 1,000 to 5,000 rad. Since, with this 

type of injury, the dose response is 

nonlinear and has a threshold (i.e., is 

nonstochastic), there is an exposure 

below which injury is not expected. If 

the shape of the injury dose-response 

curve is the same for all internal 

organs as it is for the lung, plotting the 

two acute exposure equivalents (TD 

50/5 and 5/5) for each organ on log 

probability paper allows a crude 

estimation of the number of clinical 

pathophysiological effects per 1000 

persons exposed as a function of dose 

level. If one acute effect per 1000 

persons within 5 years (TD 0.1/5) is 

taken as the threshold for the initiation 

of clinical pathophysiological effects in 

organs other than thyroid, the 

equivalent dose level for most organs is 

550 rets or more; testes 440 + 150 rets, 

ovary 170 + 70 rets, and bone marrow 

165 rets. 

The radiation exposure to organs in 

rad units that will cause clinical 

pathophysiological effects within 5 

years to 0.1 percent of the exposed 

population as a function ofthe duration 

of a continuous level of exposure can 

then be estimated by using Goitein's 

modification of the Kirk methodology 

(G0-76). This relationship is shown in 

Table B-3. 

Bone marrow is an organ of 

particular concern because 

radionuclides known to concentrate in 

this organ system occur in nuclear 

incidents. The acute lethality due to 

the hematologic syndrome (LA-67) is 

estimated to occur in the range of 200 

to 1,000 rad, so that the difference is 

small between exposure levels that 

might cause acute lethality and 

exposure levels that might cause only 

"severe clinical pathophysiology," as 

derived from radiotherapy data. 

In summary, organ systems are not 

expected to show symptoms of severe 

clinical pathophysiology for projected 

short-term· exposure doses less than a 

few hundred rad. Projected doses to 

bone marrow at this high level are 

relatively more serious and more likely 

to result in injury than doses to other 

organ systems. '· 

B-13 

Table B-1 Radiation Doses Causing Acute Injury to Organs (RU-72, RU-73) 

Volume or Risk ofinjury in five years 

Organ 	 area of 5 percent 50 percent 

exposurea (rad) (rad) Type of injury 

Bone whole 250 450 aplasia and 

marrow pancytopenia 

Liver segment 3000 4000 acute and chronic 

whole 2500 4000 hepatitis 

Stomach 100 cm2 4500 5500 ulcer, perforation, 

hemorrhage 

Intestine 400 cm2 4500 5500 ulcer, perforation, 

100 cm2 5000 6500 hemorrhage 

Lung whole 1500 2500 acute and chronic 

100 cm2 3000 3500 pneumonitis 

Kidney whole 2000 2500 acute and chronic 

nephrosclerosis 

Brain whole 6000 7000 infarction, 

necrosis 

Spinal 10 em 4500 5500 infarction, 

cord necrosis 

Heart 60 percent 4500 5500 pericarditis and 

pancarditis 

Skin 5500 7000 ulcers, fibrosis 

Fetus whole 200 400 death 

Lens of whole 500 1200 cataracts 

eye 

Ovary whole 200-300 625-1200 permanent 

sterilization 

Testes whole 500-1500 2000 permanent 

sterilization 

•nose delivered in 200-rad fractions, 5 fractions/week. 

--- Unspecified. 

B-14 

Table B-2 Acute Radiation Exposure as a Function ofRad Equivalent TherapyUnits ~~) 

Volume or Organ area of 

exposure 

Bone marrow whole 

segment 

Liver whole 

Stomach 100 cm2 

Intestine 400 cm2 

100 cm2 

Lung whole 

100 cm2 

75 percent 

Kidney whole 

Brain whole 

Spinal cord 10 em 

Heart 60 percent 

Skin 

Fetus whole 

Lens of eye whole 

Ovary whole 

Testes whole 

(sterilization) 

. . 

Risk ofinjury in five years 

5 percent 50 percent 

(rets) (re~) 

230 340 


1135 1360 


1000 1360 


1465 1665 


1465 1665 


1570 1855 


720 1000 


1135 1245 


770b 


875 1000 


1770 1950 


1465 1665 


1465 1665 


1665 1950 


200 315 


355 620 


200-430a 410-875a 


340-720a 410-875a 


aFor a 200-rad/treatment, 5 treatments/week schedule (LU-76). 

bReference WA-73. 

--- Unspecified. 

B-15 

Table B-3 	 Radiation Exposure to Organs Estimated to Cause Clinical 

Pathophysiological Effects within 5 Years to 0.1 Percent of the 

Exposed Population (G0-76) 

Duration of 

exposure Ovary Bone marrow Testes Other organs 

(days) (rad) (rad) (rad) (rad) 

(acute) (170 rets)a (165 rets) (440 rets) (550 rets) 


1 315 300 810 1020 


2 390 380 1010 1260 


4 470 450 1210 1510 


7 550 540 1430 1790 


30 840 820 2190 2740 


365b 1740 1690 4510 5640 


"The dose in rets is numerically equal to the dose in rads. 

bAssuming tissue recovery can continue at the same rate as observed during 30- to 60-day 

therapeutic exposure courses. 

Even if severe clinical 

pathophysiological effects can be 

avoided, there is still a possibility of 

clinical pathophysiological effects of a 

less severe or transitory nature. The 

1982 UNSCEAR report (UN-82) 

reviewed much of the data on animals 

and man. In the animal studies, there 

were reports of: changes in stomach 

acid secretion and stomach emptying at 

50 to 130 rad; stunting in growing 

animals at the rate of 3 to 5 percent 

per 100 rad; degeneration ofsome cells 

or functions in the brain at 100 rad, 

particularly in growing animals; 

temporary changes in weight of 

hematopoietic tissues at 40 rad; and 

more damage in ovaries and testes 

caused by fractionated doses rather 

than acute doses. Some of the effects 

are transitory, others are long-lasting, 

but with only minor reductions in 

functional capacity. 

Human data are limited and are 

reported primarily in the radiotherapy 

literature. The data suggest most 

tissues in man are more radiation 

resistant than those in animals. 

However, the human hematopoietic 

system shows a transient response, 

reflected by decreased circulating white 

cells and platelets, at about 50 rad. 

Temporary sterility has been observed 

after doses of 150 rad to the ovaries 

and 10 rad to the testes, when given as 

fractionated doses. 

There is not sufficient data to 

determine dose-response functions 

B-16 

nor to describe the duration and 

severity of dysfunction expected. 

B.2.2 Summary and Conclusions 

Regarding Acute Effects 

Based on the foregoing review of 

acute health effects and other biological 

effects from large doses delivered over 

short periods of time, the following 

whole body doses from acute exposure 

provide useful reference levels for 

decisionmaking for PAGs: 

50 rad - Less than 2 percent of the 

exposed population would be 

expected to exhibit prodromal 

(forewarning) symptoms. 

25 rad - Below the dose where 

prodromal symptoms have 

been observed. 

10 rad - The dose level below which a 

fetus would not be expected 

to suffer teratogenesis (but 

see Section B.3, Mental 

Retardation.). 

5 rad - The approximate rmmmum 

level of detectability for acute 

cellular effects using the most 

sensitive methods. Although 

these are not severe 

pathophysiological effects, 

they may be detrimentaL 

Based on the first principle to be 

satisfied by P AGs (paragraph B.1.6), 

which calls for avoiding acute health 

effects, values of 50 rem for adults and 

10 rem for fetuses appear to represent 

upper bounds. ~ 

B.3 Mental Retardation 

Brain damage to the unbom is a 

class of injury reported in atomic bomb 

survivors which does not fall into 

either an acute or delayed effect 

category, but exhibits elements ofboth. 

What has been observed is a 

significant, dose-related increase in the 

incidence and severity of mental 

retardation, microencephaly (small 

head size), and microcephaly (small 

brain size) in Japanese exposed to 

radiation in utero during the 8th to 

15th week after conception (BL-73; 

MI-76). While the actual injury may be 

acute, it is not identified until some 

time after birth. 

In an early study Mole (M0-82) 

suggested that, although radiation 

may not be the sole cause of these 

conditions, it is prudent to treat the 

phenomenon as radiation-related. 

More recently, Otake and Schull 

(OT-83) have concluded: (1) there is no 

risk to live-hom due to doses delivered 

up to 8 weeks after conception, (2) most 

damage occurs at the time when rapid 

proliferation of neuronal elements 

occurs, i.e., 8 to 15 weeks of gestational 

age, (3) the dose-response function for 

incidence during this period appears to 

fit a linear model, ( 4) the risk of 

occurrence is about five times greater 

during the . period 8-15 weeks of 

gestation than in subsequent weeks, 

and (5) in later stages ofgestation, e.g., 

after the 15th week, a threshold for 

damage may exist. 

In their published reports, Otake 

and Schull (OT-83) evaluated the 

incidence of severe mental retardation 

B-17 

using the T-65 dosimetry and the 

dosimetry estimates developed in the 

ongoing dose reassessment programfor 

the atomic bomb survivors, and using 

two tissue dose models. Their 

estimated ranges ofrisk were: 

8 to 15 weeks after gestation: 

3-4x10'.3 cases/rad; 

16 or more weeks after gestation: 

5-7x104 cases/rad. 

The higher values are based on the 

T-65 dosimetry and the Oak Ridge 

National Laboratory estimate oftissue 

dose. The lower values are based on 

Oak Ridge National Laboratory 

dosimetry and the Japanese National 

Institute of Radiological Sciences 

estimates of tissue dose. Later 

estimates based on the dose 

reassessment completed in 1986 are 

consistent with these published results 

(SC-87). 

In view of the foregoing, the risk of 

mental retardation from exposure of a 

fetus in the 8th to 15th week of 

pregnancy is taken to be about 4x10.3 

per rad. Because ofthis relatively high 

risk, special consideration should be 

given to protection of the fetus during 

this period. The risk to a fetus exposed 

after the 15th week is taken as 6x10·4 

per rad. For the cases studied (OT-84), 

no increased incidence of mental 

retardation was observed for exposure 

during the 1st to the 7th week of 

pregnancy. 

Federal Radiation Protection 

Guidance, adopted in 1987, 

recommends that dose to occupationally 

exposed pregnant women be controlled 

to keep the fetal dose below 0.5 rem 

over the entire term of pregnancy, and 

that no dose be delivered at more than 

the uniform monthly rate that would 

satisfY this limit (i.e., approximately 

50-60 mrem/month)(EP-87). The 

NCRP has, for many years, 

recommended a limit of 0.5 rem 

(NC-71). ICRP recommends controlling 

exposure of the fetus to less than 0.5 

rem in the first 2 months to provide 

appropriate protection during the 

essential period of organogenesis 

(IC-77). 

B.4 Delayed Health Effects 

This section addresses information 

relevant to the second principle 

(paragraph B.1.5) for establishing 

P AGs, the risk ofdelayed health effects 

in exposed individuals. The following 

subsections summarize the estimated 

risks of cancer and genetic effects, the 

two types of delayed effects caused by 

exposure to radiation. 

B.4.1 Cancer 

Because the effects of radiation on 

human health have been more 

extensively studied than the effects of 

many other environmental pollutants, 

it is possible to make numerical 

estimates of the risk as a result of a 

particular dose of radiation. Such 

estimates, may, however, give an 

unwarranted aura of certainty to 

estimated radiation risks. Compared 

to the baseline incidence of cancer and 

genetic defects, radiogenic cancer and 

B-18 

genetic defects do not occur very 

frequently., Even in heavily irradiated 

populations, the number of cancers and 

genetic defects resulting from radiation 

is lmown with only limited accuracy. 

In addition, all members of existing 

exposed populations have not been 

followed for their full lifetimes, so data 

on the ultimate numbers of effects is 

not yet available. Moreover, when 

considered in light of information 

gained from experiments with animals 

and from various theories of 

carcinogenesis and mutagenesis, the 

observed data on the effects of human 

exposure are subject to a number of 

interpretations. This, in turn, leads to 

differing estimates ofradiation risks by 

individual scientists and expert groups. 

In summary, the estimation of 

radiation risks is not a fully mature 

science .and the evaluation ofradiation 

hazards will continue to change as 

additional information becomes 

available. 

Most of the observations of 

radiation-induced carcinogenesis in 

humans are on groups exposed to 

low-LET radiations. These groups 

include the Japanese A-bomb survivors 

and medical patients treated with 

x-rays for ankylosing spondylitis in 

England from 1935 to 1954 (SM-78). 

The National Academy of Science 

Committee on the Biological Effects of 

Ionizing Radiations (BEIR) (NA-80) 

and UNSCEAR (UN-77) have provided 

knowledgeable and exhaustive reviews 

of these and other data on the 

carcinogenic effects of human 

exposures. The most recent of the 

BEIR studies was published in 1980 

and is here designated BEIR-3 to 

distinguish it from previous reports of 

the BEIR committee. 

The most important epidemiological 

data on radiogenic cancer is that from 

the A-bomb survivors. The Japanese 

A-bomb survivors have been studied for 

more than 40 years, and most of them 

have been followed in a major, carefvlly 

planned and monitored epidemiological 

survey, the Life $pan Study Sample, 

since 1950 (KA-82, WA-83). They were 

exposed to a wide range of doses and 

are the largest group that has been 

studied. They are virtually the only 

group providing extensive information 

on the . response pattem at various 

levels ofexposure to low-LET radiation. 

The estimated cancer risk from 

low-LET, whole body, lifetime exposure 

presented here is based on a life table 

analysis using a linear response model. 

We use the ·arithmetic average of 

relative and absolute risk projections 

(the BEIR-3 L-L model) for solid 

cancers, and an absolute risk projection 

for leukemia and bone cancer (the 

BEIR-3 L-L model). For whole body 

dose, this yields an estimated 280 (with 

a possible range of 120 to 1200) 

fatalities per million person-rem for a 

population cohort representative ofthe 

1970 U.S. population. We assume this 

estimate also applies to high-LET 

radiation (e.g. alpha emitters); no 

reduction has been applied for dose 

rate. (The rounded value, 3x10"4 

fatalities3 per person-rem, has been 

selected for this analysis.) 

3

Preliminary reviews of new results from 

studies of populations exposed at Hiroshima 

B-19 

Whole body dose means a uniform 

dose to every organ in the body. In 

practice, such exposure situations 

seldom occur, particularly for ingested 

or inhaled radioactivity. Inhaled 

radioactive particulate materials may 

be either soluble or insoluble. Soluble 

particulate materials deposited in the 

lung will be rapidly absorbed, and the 

radionuclides associated with them 

distributed throughout the body by the 

bloodstream. As these radionuclides 

are transported in the blood, they 

irradiate the entire body. Usually, 

they then redeposit in one or more 

organs, causing increased irradiation of 

that organ. Insoluble particulate 

materials, on the other hand, are only 

partially absorbed into body fluids. 

(This fraction is typically assumed to 

be about 8 percent.) This absorption 

occurs over a period of years, with a 

portion entering the bloodstream and 

another retained in the pulmonary 

lymph nodes. The balance (92 percent) 

of inhaled insoluble particulate 

materials are removed from the lung 

within a few days by passing up the air 

passages to the pharynx where they 

are swallowed. Inhaled insoluble 

particulate materials thus irradiate 

both the lung and the gastrointestinal 

tract, with a small fraction being 

eventually absorbed into the 

(footnote continued) 

and Nagasaki indicate that these risk 

estimates may be revised upwards significantly 

in the near future, particularly for acute 

exposure situations. EPA has recently used a 

slightly higher value, 4 x 10"4 fatalities in 

standards for air emissions under the Clean 

Air Act. We will revise these risk estimates to 

reflect new results following appropriate 

review. 

bloodstream (TG-66). These 

nonuniform distributions of dose (and 

therefore risk) are taken into account 

through use ofthe weighting factors for 

calculating effective dose. 

There is a latent period associated 

with the onset of radiation-induced 

cancers, so the increased risk is not 

immediately apparent. The increased 

risk is assumed to commence 2 to 10 

years after the time of exposure and 

continue the remainder of the exposed 

individual's lifespan (NA-80). 

For uniform exposure of the whole 

body, about 50 percent of 

radiation-induced cancers in women 

and about 65 percent in men are fatal 

(NA-80). Therefore, 1 rem oflow-LET 

radiation would be expected to cause a 

total of about 500 cancer cases if 

delivered to a population ofone million. 

(In the case of thyroid and skin, the 

ratio of nonfatal to fatal cancers are 

much higher. These are addressed 

separately below.) This corresponds to 

an average annual individual 

probability of developing cancer of 

about 7x10"6 per year. For perspective, 

the average annual risk of dying of 

cancer from all causes in the United 

States, in 1982, was 1.9x10"3 

• 

B.4.1.1 Cancer Risk Due to Radiation 

Exposure of the Thyroid 

Exposure of the thyroid to 

extremely high levels of radiation may 

cause it to degenerate. At moderate 

levels of exposure some loss of thyroid 

function will occur. At lower levels of 

exposure, there are delayed health 

B-20 

effects, which take the form of both 

thyroid nodules and thyroid 

malignancies (NA-72; NA-80). Doses 

as low as 14 rad to the thyroid have 

been associated with thyroid 

malignancy in the Marshall Islanders 

(C0-70). The increased risk of 

radiation-induced cancer is assumed to 

commence about 10 years after initial 

exposure and to continue for the 

remaining lifespan of an exposed 

individual. 

The true nature of thyroid nodules 

cannot be established until they are 

surgically removed and examined 

histologically, and those that are 

malignant can lead to death if not 

surgically removed (SA-68; DE-73; 

PA-74). Although thyroid malignancies 

are not necessarily fatal, effects 

requiring surgical removal of the 

thyroid cannot be considered benign. 

In this analysis, all thyroid cancers, 

both fatal and nonfatal, are counted for 

the purpose of estimating the severity 

of thyroid exposures. 

Based on findings in BEIR-3, we 

estimate that 1 rem ofthyroid exposure 

carries a risk of producing a thyroid 

cancer of 3.6x1o-4, of which a small 

fraction (on the order of 1 in 10) will be 

fatal (NA-80). Since the calculation of 

effective dose equivalent does not 

include consideration of nonfatal 

thyroid cancers and the severity of the 

medical procedures for their cure, it is 

appropriate to limit the dose to the 

thyroid by an additional factor beyond 

that provided by the PAG expressed in 

terms of effective dose equivalent. 

Protective action to limit dose to 

thyroid is therefore recommended at a 

thyroid dose ·5 times the numerical 

value of the P AG for effective dose. 

B.4.1.2 Cancer Risk Due to Radiation 

Exposure of the Skin 

The risk of fatal skin cancer is 

estimated to be on the order of one 

percent of the total risk of fatal cancer 

for uniform irradiation of the entire 

body (IC-78). However, since the 

weighting scheme for calculating 

effective dose equivalent does not 

include skin, the P AG expressed in 

terms of effective dose does not provide 

protection against radionuclides which 

primarily expose skin. As in the case 

of the thyroid, the ratio of nonfatal to 

fatal cancers from irradiation of the 

skin is high (on the order of 100 to 1). 

It would not be appropriate to ignore 

this high incidence of nonfatal skin 

cancers by allowing 100 times as much 

dose to the skin as to the whole body. 

For this reason, evacuation is 

recommended at a skin dose 50 times 

the numerical value of the PAG for 

effective dose. 

B.4.1.3 Cancer Risk Due to Radiation 

Exposure of the Fetus 

The fetus is estimated to be 5 to 10 

times as sensitive to radiogenic cancer 

as an adult (FA-73; WH-65). Stewart 

reports increased relative incidence of 

childhood cancers following prenatal 

x-ray doses as low as 0.20 to 0.25 reni 

and doubling of childhood cancers 

between 1-4 rem (ST-73). She 

concluded that the fetus is about 

equally sensitive to cancer induction in 

B-21 

each trimester. Her findings are 

supported by similar results reported 

by MacMahon and Hutchinson 

(MA-64), Kaplan (KA-58), Polhemus 

and Kock (P0-59), MacMahon (MA-63), 

Ford, et al. (F0-59), Stewart and 

Kneale (ST-70b), and an AEC report 

(AE-61). MacMahon reported that 

although there were both positive and 

negative findings, the combination of 

weighted data indicates a 40 percent 

increase in childhood cancer mortality 

after in vivo exposure to diagnostic x 

rays (1.0 to 5.0 rad): about 1 cancer 

per 2,000 exposed children in the first 

10 years after birth (MA-63). He 

concluded that although the range of 

dose within which these effects are 

observed is wide, effects will be fewer 

at 1 rad than at 5 rad. 

Graham, et al., investigating 

diagnostic x-ray exposure, found a 

significantly increased relative risk of 

leukemia in children: by a factor of 1.6 

follo·wing preconception irradiation of 

mothers or in utero exposure of the 

fetus; by a factor of 2 following 

postnatal irradiation of the children; 

and by a factor of 2 following 

preconception irradiation ofthe mother 

and in utero exposure of the child 

(GR-66). 

B.4.1.4 Age Dependence of Doses 

Almost all dose models are based on 

ICRP "Reference Man," which adopts 

the characteristics of male and female 

adults of working age. ICRP-30 

dosimetric models, which use 

"Reference Man" as a basis, are 

therefore appropriate for only adult 

workers and do not take into account 

differences in dose resulting from the 

differences in physiological parameters 

between children and adults, e.g., 

intake rates, metabolism, and organ 

size. Although it is difficult to 

generalize for all radionuclides, in some 

cases these differences tend to 

counterbalance each other. For 

example, the ratio of volume of air 

breathed per unit time to lung mass is 

relatively constant with age, so that 

the ICRP adult model for inhaled 

materials provides a reasonably good 

estimate of the dose from a given air 

concentration of radioactive material 

throughout life. 

The thyroid is an exception because 

the very young have a relatively high 

uptake ofradioiodine into a gland that 

is much smaller than the adult thyroid 

(see Section B.4.2.2.). This results in a 

larger childhood dose and an increased 

risk which persists throughout life. We 

have examined this worst case 

situation. Age-specific risk coefficients 

for fatal thyroid cancer (See Table 6-8 

of "Risk Assessment Methodology" 

(EP-89)) are about 1.9 higher per unit 

dose for persons exposed at ages 0 to 9 

years than for the general population. 

Age-dependent dose factors (see 

NRPB-R162 (GR-85)) for inhalation of 

I-131, are a factor of about 1.7 higher 

for 10 year olds than for adults. 

Therefore, the net risk of fatal thyroid 

cancer from a given air concentration of 

I-131 is estimated to be a factor of 

about 3 higher for young children than 

for the remainder of the population. 

This difference is not considered large 

enough, given the uncertainties of 

exposure estimation for implementing 

B-22 

protective actions, to warrant 

establishing age-dependent P AGs. 

B.4.2 Genetic Risk 

An average parental dose of 1 rem 

before conception has been estimated to 

produce 5 to 75 significant 

genetically-related disorders per million 

liveborn offspring (NA-80). . For this 

analysis we use the geometric mean of 

this range, i.e. 1.9x10"5

• This estimate 

applies to effects in the first generation 

only, as a result of dose to parents of 

liveborn offspring. The sum of effects 

over all generations is estimated to be 

approximately twelve times greater; 

that is, 2.3x10"4

• In addition, since any 

radiation dose delivered after a 

parent's last conception has no genetic 

effect, and not all members of the 

population become parents, less than 

half of the entire dose in an average 

population is of genetic significance. 

Taking the above factors into account, 

we estimate that the risk of 

genetically-related disorders in all 

generations is 1x10"4 per person-rem to 

a typical population. 

Although the overall severity of the 

genetic effects included as "significant" 

in the above estimates is not well 

known, rough judgements can be made. 

The 1980 . BEIR report referred to 

" .... disorders and traits that cause a 

serious handicap at some time during 

lifetime" (NA-80). From the types of 

defects reported by Stevenson (ST-59), 

it can be estimated that, of all 

radiation-induced genetic effects, 50 

percent lead to minor to moderate 

medical problems (i.e., hair or ear 

anomalies, polydactyl, strabismus, etc.), 

25 percent lead to severe medical 

problems (i.e., congenital cataracts, 

diabetes insipidus, deaf mutism, etc.), 

23 percent would require extended 

hospitalization (i.e., mongolism, 

pernicious anemia, manic-depressive 

psychoses, etc.), and 2 percent .would 

die before age 20 (i.e., anencephalus, 

hydrocephalus, pancreatic fibrocytic 

disease, etc.). 

B.4.3 Summary of Risks of Delayed 

Effects 

Table B-4 summarizes average 

lifetime risks of delayed health effects 

based on results from the above 

discussion. Because of the nature of 

the dose-effect relationships assumed 

for delayed health effects · from 

radiation (linear, nonthreshold), there 

is no dose value below which no risk 

can be assumed to exist. 

B.4.4 Risks Associated with Other 

Radiation Standards 

A review of radiation standards for 

protection of members of the general 

population from radiation shows a 

range ofvalues spanning several orders 

of magnitude. This occurs because of 

the variety of bases (risk, cost, 

practicability of implementation, and 

the situations to which they apply) that 

influenced the choice of these 

standards. Some source-specific 

standards are relatively protective, e.g., 

the EPA standard limiting exposure of 

the public from nuclear power 

operations (25 mrem/y) from all pathB-23 

Table B-4 Average Risk of Delayed Health Effects in a Populationa 

Effects per person-rem 

Whole Body Thyroidc Skin 

Fatal cancers 2.8E-4b 3.6E-5 3.0E-6 

Nonfatal cancers 3.2E-4 3.0E-4 

Genetic disorders l.OE-4 

(all generations) 

• We assume a population with the same age distribution as that of the U.S. population in 1970. 


bRisk to the fetus is estimated to be 5 to 10 times higher. 


c Risk to young children is estimated to be about two to three times as high. 


ways combined corresponds to a risk 

(for cancer death) of 5x10-4 for lifetime 

exposure. Similarly, regulations under 

the Clean Air Act limit the dose due to 

emissions of radionuclides to air alone 

from all DOE and NRC facilities to 

0.01 rem per year, which corresponds 

to a cancer risk o;f 2x10-4 for lifetime 

exposure. Other guides permit much 

higher risks. For example, the level at 

which the EPA recommends action to 

reduce exposure to indoor radon (0.02 

working levels) corresponds to a risk of 

about 2x10-2 (for fatal lung cancer) for 

lifetime exposure. All of these 

standards and guides apply to 

nonemergency situations and were 

based on considerations beyond a 

simple judgement of acceptable risk. 

Federal Radiation Protection 

Guidance for nonemergency situations 

recommends that the dose from all 

sources combined (except from 

exposure to medical and natural 

background radiation) to individuals in 

the population not exceed 0.5 rem in a 

single year (FR-60) and that the dose 

to the fetus of occupationally-exposed 

mothers not exceed 0 _5 rem during the 

9-month gestation period (EP-87). This 

dose corresponds to an annual 

incremental risk of fatal cancer to 

members of the general population of 

about 1.4x10-4

• Ifexposure ofthe fetus 

is limited to one ninth of 0.5 rem per 

month over a 9-month gestation period, 

as recommended, the risk of severe 

mental retardation in liveborn is 

limited to about 7x10-4• 

The International Commission on 

Radiation Protection recommends that 

the dose to members of the public not 

exceed 0.5 rem per year due to 

nonrecurring exposure to all sources of 

radiation combined, other than natural 

sources or beneficial medical uses of 

B-24 

radiation (IC-77). They also 	 Radioiodine: Principles of Nuclear Medicine. 

Ed. H.N. Wagner, Jr. pp. 343-369, W.B. recommend a limiting dose to members 

Saunders Company, Philadelphia (1968). of the public of 0.1 rem per year from 

all such sources combined for chronic 

(i.e., planned) exposure (IC-84a). These 

upper bounds may be taken as 

representative of acceptable values for 

the situations to which they apply. 

That is, these are upper bounds of 

individual risk that are acceptable for 

the sum of all sources and exposure 

pathways under international 

recommendations, for circumstances 

that are justified on the basis of public 

benefit, and when actual doses from 

individual sources are "as low as 

reasonably achievable" (ALARA) within 

these upper bounds. 

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B-30 

APPENDIXC 

Protective Action Guides for the Early Phase: 

Supporting Information 

Contents 

Page 

C.1 Introduction ........................................... C-1 


C.1.1 Existing Federal Guidance .................•......... C-1 


C.1.2 Principal Exposure Pathways . . . . . . . . . . . . . . . . . . . . . . . . C-2 


C.2 	 Practicality of Implementation . . . . . . . . . . . . . . . . . . . . . . . . . . . . C-3 


C.2.1 Cost of Evacuation ................................ C-3 


C.2.1.1 Cost Assumptions ........................... C-4 


C.2.1.2 Analysis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . C-5 


C.2.1.3 Conclusions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . C-10 


C.2.2 	Risk of Evacuation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . C-10 


C.2.3 Thyroid Blocking .................................. C-13 


C.2.4 	Sheltering . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . C-14 


C.3 	 Recommended PAGs for Exposure to a Plume during the 


Early Phase . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . C-17 


C.4 	 Comparison to Previous PAGs C-21 


C.5 	 Dose Limits for Workers Performing Emergency Services. C-22 


References . . ............................................. . C-24
 .. ., 

Figures 

C-1 Evacuation Model . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . C-6 


Tables 

C-1 	 Costs for Implementing Various PAGs for an SST-2 Type 


Accident (Stability Class A) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . C-7 


lll 
Tables (continued) 

Page 

C-2 Costs for Implementing Various PAGs for an SST-2 Type 

Accident (Stability Class C) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . C-8 

C-3 Costs for Implementing Various PAGs for an SST-2 Type 

Accident (Stability Class F) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . C-9 

C-4 Upper Bounds on Dose for Evacuation, Based on the Cost 

of Avoiding Fatalities . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . C-11 

C-5 Average Dose Avoided per Evacuated Individual for 

Incremental Dose Levels for Evacuation . . . . . . . . . . . . . . . . . . . . . C-12 

C-6 Representative Dose Reduction Factors for External 

Radiation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . C-14 

C-7 Dose Reduction Factors for Sheltering from Inhalation 

of Beta-Gamma Emitters ..................... : . . . . . . . . . . C-16 

C-8 Summary of Considerations for Selecting the 

Evacuation P AGs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . C-18 

C-9 Comparison of Projected Doses for Various Reactor 

Accident Scenarios ................................. ~ . . . C-21 

C-10 Cancer Risk to Emergency Workers Receiving 25 Rem Whole 

Body Dose . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . C-24 

iv 
APPENDIXC 


Protective Action Guides for the Early Phase: 


Supporting Information 


C.1 Introduction 

This appendix sets forth supporting 

information for the choice ofProtective 

Action Guides (PAGs) for the early 

phase of the response to a nuclear 

incident involving the release of 

airborne radioactive material. It then 

describes application of the basic 

principles for selection of response 

levels set forth in Chapter 1 to the 

guidance on evacuation and sheltering 

in Chapters 2 and 5. 

Response to a radiological 

emergency will normally be carried out 

in three phases, as discussed in 

Chapter 1. Decisions during the first 

(early) phase will usually be based on 

predicted or potential radiological 

conditions in the environment, rather 

than on actual measurements. The 

principal protective action is 

evacuation, with sheltering serving as 

a suitable alternative under some 

conditions. This appendix examines 

the potential magnitudes and 

consequences of predicted exposures of 

populations during the early phase, for 

selected nuclear reactor accident 

scenarios, in relation to the benefits 

and detrimental consequences of 

evacuation and sheltering. Nuclear 

reactor facilities are chosen for 

evaluation because, due to their 

number, size of source, and energy 

available to drive a release, they are 

most likely to provide an upper bound 

on the magnitude of the variety of 

possible sources of nuclear incidents. 

Although atmospheric releases from 

other types of nuclear incidents are 

likely to involve smaller consequences, 

the affected populations, and therefore 

the costs and benefits of protective 

action are each expected to scale in 

roughly the same proportion for lesser 

magnitude incidents. Thus, basic 

conclusions developed for respo'nses to 

reactorfacilities are assumed to remain 

valid for other types of nuclear 

incidents. Supplementary protective 

actions, such as washing and change of 

clothing to re<;luce exposure of the skin 

and use of stable. iodine to · reduce 

uptake of radioiodine to the thyroid, 

are also considered, but in less detail. 

C.l.l Existing Federal Guidance 

In the 1960's, the Federal Radiation 

Council (FRC) defined PAGs and 

established limiting guides for 

ingestion of strontium-89, 

strontium-90, cesium-137, and 

iodine-131 (FR-64; FR-65). That 

guidance applied to restricting the use 

of food products that had become 

contaminated as the result ofrelease of 

radioactivity to the stratosphere from 

weapons testing. During the period 

immediately following an incident at 

any domestic nuclear facility, when the 

C-1 

critical source of exposure is expected 

to be a nearby airborne plume, the 

principal protective actions are 

evacuation or sheltering. The P AGs 

developed here thus do not supersede 

previous guidance, but provide 

additional guidance for prompt 

exposure pathways specific to a 

domestic nuclear incident. 

C.1.2 Principal Exposure Pathways 

The immediate exposure pathway 

from a sub-stratospheric airborne 

release of radioactive materials is 

direct exposure from the cloud of 

radioactive material carried by 

prevailing winds. Such a plume can 

contain radioactive noble gases, 

iodines, and/or particulate materials, 

depending on the source involved and 

conditions of the incident. These 

materials emit gamma rays, which are 

not significantly absorbed by air, and 

will expose the entire bodies of nearby 

individuals. 

Another immediate exposure 

pathway occurs when people are 

submerged in the cloud of radioactive 

materials. In this case radioactive 

materials are inhaled, and the skin and 

clothes may be contaminated. Inhaled 

radioactive materials, depending on 

their solubility in body fluids, may 

either remain in the lungs or move via 

the blood to other organs. Many 

radionuclides which enter the 

bloodstream tend to be predominantly 

concentrated in a single organ.· For 

example, ifradioiodines are inhaled, a 

significant fraction will tend to move 

rapidly from the lungs through the 

bloodstream to the thyroid gland where 

much of the iodine will be deposited 

and most ofthe dose1 will be delivered. 

Although dose to skin from materials 

deposited on the skin and clothing 

could be significant, it will be less 

important in terms of risk of fatal 

cancer than dose from inhalation, if 

early protective actions include 

washing ofexposed skin and changes of 

clothing. 

As the plume passes over an area, 

radioactive materials may settle onto 

the ground and other surfaces. People 

remaining in the area will then 

continue to be exposed through 

ingestion and external radiation, and 

through inhalation of resuspended 

materials. The total dose from such 

deposited materials may be more 

significant than that due to direct 

exposure to the plume, because the 

term of exposure can be much longer. 

However, since the protective actions 

considered here (evacuation and/or 

sheltering) may not be appropriate or 

may not apply for this longer term 

exposure, doses from these exposures 

beyond the early phase are not 

included in the dose considered in the 

P AGs for the early phase. It is 

assumed that, within four days after 

an incident, the population will be 

1

In this and all subsequent references, the 

word "dose" means the committed dose 

equivalent to the specified organ, or, if no 

organ is specified, the sum of the committed 

effective dose equivalent from intake of 

radionuclides and the effective dose equivalent 

from external sources of radiation. (Section 

B.l.l contains a more detailed discussion of 

units of dose for PAGs.) 

C-2 

protected from these subsequent doses 

on the basis of the P AGs for relocation 

and for contaminated food and water. 

(See Chapters 3 and 4.) 

Based on the foregoing 

considerations, the PAGs for the early 

phase are expressed in terms of 

estimated doses from exposure due to 

extemal radiation, inhalation, and 

contamination of the skin only during 

the early phase following an incident. 

C.2 Practicality of Implementation 

Whereas Appendix B deals with the 

risk associated with the projected dose 

that could be avoided by any protective 

action, this section addresses the costs 

and risks associated with evacuation 

itself. That is, these analyses relate to 

Principles 3 and 4 for deriving P AGs, 

set forth in Chapter 1, which address 

the practicality of protective actions, 

rather than acceptability ofrisks under 

Principles 1 and 2, which is evaluated 

in Appendix B. 

The principal relevant protective 

actions during the early phase are, as 

noted earlier, evacuation and 

sheltering. In some cases, washing and 

changing of clothing, or thyroid 

blocking may also be appropriate 

actions. The costs, risks, and degrees 

of protection associated with 

evacuation are generally higher than 

those for sheltering. Although there 

may be some costs and risks associated 

with the other protective actions, they 

are small and not readily quantifiable. 

Therefore, only the costs and risks 

associated with evacuation will be 

evaluated here. These factors are 

evaluated to determine whether the 

costs are low enough to justify lower 

P AGs than would be required to satisfy 

upper bounds of acceptable risk under 

Principles 1 and 2. 

C.2.1 Cost of Evacuation 

Costs incurred to reduce the 

radiation risk from nuclear incidents 

can be considered to fall into several 

major categories. The first category 

includes the design, construction, and 

operation of nuclear facilities in such a 

manner as to minimize the probability 

and consequences of radiological 

incidents. It is recognized that the 

probability and consequences of such 

incidents usually cannot be reduced to 

zero. Therefore, a second category is 

necessary: the development· of 

emergency response plans to invoke 

actions which would reduce exposure of 

potentially exposed populations, and 

consequently their risks, if a maJor 

nuclear incident should occur. 

Both of the above categories of cost 

are properly attributed to the cost of 

design and operation of a nuclear 

facility. A third category of costs is the 

actual expenses incurred by taking 

protective actions as the result of an 

incident. In general, the choice of 

levels for P AGs will affect only this 

third category of costs. That is, all 

costs in the first two categories are 

assumed to be unaffected by decisions 

on the levels ofPAGs. (This will be the 

case unless the P AGs were to be set so 

high as to never require protective 

action, in which case response plans 

C-3 

would be unnecessary.) Therefore, the 

costs associated with implementing the 

P AGs are evaluated only in terms of 

the actual cost of response. In a 

similar manner, the risk incurred by 

protective actions is compared only to 

the risk associated with the radiation 

dose that would be avoided by the 

action, and is unaffected by any other 

measures taken to reduce risks that 

fall in the first two categories of cost 

identified above. 

0.2.1.1 Cost Assumptions 

The analyses in this section are 

based on evaluation of the costs of 

evacuation and the doses that would be 

received in the absence of protective 

actions for nuclear reactor incidents. 

These were calculated as a function of 

offsite location, meteorological 

condition, and incident type (TA-87). 

Dose and cost data are based on the 

following assumptions: 

1. Airborne releases are those 

associated with fuel melt accidents at 

nuclear reactor facilities followed by 

containment failure. 

2. Meteorological conditions range 

from stable to unstable, and 

windspeeds are those typical of the 

stability class. 

3. Plume dispersion follows a 

Gaussian distribution, with a 0.01 m/s 

dry deposition velocity for iodine and 

particulate materials. 

. 4. Doses are those incurred from 

whole body gamma radiation from the 

plume, inhalation of radioactive 

material in the plume, and from four 

days exposure to deposited radioactive 

material. 

5. Population distributions are the 

average values observed around 111 

nuclear power reactor plants, based on 

1970 data. 

6. The cost of evacuation is $185 per 

person for a 4-day evacuation involving 

a 100-mile round trip, with an average 

of 3 persons per household. These 

evacuation costs include wages and 

salaries of personnel directing the 

evacuation, transportation costs of 

evacuees to and from the staging 

location, food and shelter for the 

evacuees during the evacuation period, 

loss of personal and corporate income 

during the evacuation period, and the 

costs of any special supplies (TA-87). 

The estimated costs and doses 

avoided are based on the following 

idealized evacuation area model (see 

Figure C.l.): 

1. All people within a 2-mile radius of 

the incident are evacuated for all 

scenarios. 

2. People are also evacuated from a 

downwind area bounded by equivalent 

rays on either side ofthe center line of 

the plume, which define the angular 

spread (70, 90, or 180 degrees) of the 

area evacuated by an arc at the 

distance beyond which the evacuation 

dose would not be exceeded on the 

plume centerline . 

C-4 

Figure C-1 shows the relationship 

between the area in which the 

evacuation dose would be exceeded and 

the larger area that might be 

evacuated. The figure shows the plume 

centered in an idealized evacuation 

area. 

C.2.1.2 Analysis 

Evaluation of costs for evacuation 

and doses to populations as a function 

of the area evacuated depends on a 

variety of assumptions. Three 

fuel-melt accident categories, six 

meteorological stability classes, and the 

three evacuation area models discussed 

above were examined. Detailed 

assumptions and data are reported 

elsewhere (EP-87 a). Selected data, 

including the cost per unit of collective 

dose to the population Figure C.1 

(person-rem) avoided, are presented in 

Tables C-1, C-2, and C-3, for three 

stability classes, for the median 

nuclear accident category examined 

(SST-2). (SST accident categories are 

described in Section E.1.2). 

The data are presented for both the 

total area and the incremental area 

evacuated for each change in dose level 

examined. When evaluating the cost 

per person-rem avoided for a speci:fic 

set of circumstances, it is appropriate 

to ·assess the ratio of the total cost to 

the total dose avoided to calculate the 

average cost per person-rem avoided. 

However, when one is comparing the 

cost versus dose avoided to make a 

judgment between a variety of different 

limiting dose values, it is appropriate 

to compare the dose savings and costs 

at the margin, since the cost of 

evacuating the additional area is 

incurred to avoid the incremental 

collective dose. Therefore, the 

appropriate quantities are the cost and 

risk for the additional area evacuated. 

Results of analyses on both a total and 

incremental basis. are presented in 

Tables C-1, C-2, and C-3 for accident 

category SST-2. This is the smallest 

category of fuel melt accident yielding 

effective dose equivalents during the 

first 4 days . of exposure that are 

greater than 0.5 rem outside the 

assumed 2-mile evacuation circle for all 

stability classes. Data on costs versus 

dose saved for all three accident 

categories are summarized inTable C-4 

in the next section. 

Changes in population density 

would not affect the above results, 

since both cost and collective dose are 

proportional to the size of ' the 

population affected. Factors that could 

affect these results are different 

assumptions for cost of evacuation, 

accident scenarios, and evacuation area 

models. The results will be directly 

proportional to different assumptions 

for the cost of evacuation. Some data 

on the variation with accident scenario 

are presented ·in the next section. In 

situations where different widths of 

evacuation area are assumed, the 

change in cost per unit dose avoided 

will be approximately proportional to 

the change in width in· degrees. This 

approximation is more accurate for the 

higher stability classes (E and F). 

Evacuation within a 2 mile radius 

circle and a 90 degree sector in the 

downwind direction is generally 

considered to be adequate for release 

C-5 

2 MILE RADIUS 

........
 ' .... . . . AREA WHERE PLUME ....·. 

: :·: : PAGs ARE EXCEEDED 

~· AREA EVACUATED' 

FIGURE C-1. EVACUATION MODEL. 

C-6 

Table C-1 Costs for Implementing Various PAGs for an SST-2 Type Accident (Stability Class A) 

Evacuation PAG Total Area Marginal Area 

angle 

(degrees) 

value 

(rem) Cost 

(dollars) 

Dose 

avoided 

(person-rem) 

Dollars/ 

person-rem 

avoided · 

!!Cost 

(dollars) 

!!Dose 

avoided 

(person-rem) 

A Dollars/ 

!!person-rem 

avoided 

70 0.5 

1 

2 

5 

10 

2.83E+7 

6.68E+6 

1.49E+6 

2.99E+5 

(a) 

8.97E+4 

4.06E+4 

1.73E+4 

5.22E+3 

(a) 

315 

164 

88 

57 

(a) 

2.16E+7 

5.19E+6 

1.19E+6 

9.70E+4 

4.91E+4 

2.33E+4 

1.21E+4 

2.44E+3 

440 

223 

98 

40 

90 0.5 

1 

2 

5 

10 

3.63E+7 

8.54E+6 

1.86E+6 

3.26E+5 

(a) 

9.29E+4 

4.24E+4 

1.82E+4 

5.41E+3 

(a) 

391 

201 

102 

60 

(a) 

2.78E+7 

6.68E+6 

1.54E+6 

1.25E+5 

5.05E+4 

2.42E+4 

1.28E+4 

2.63E+3 

550 

276 

120 

47 

180 0.5 

1 

2 

5 

10 

7.16E+7 

1.67E+7 

3.48E+6 

4.48E+5 

(a) 

9.33E+4 

4.27E+4 

1.84E+4 

5.46E+3 

(a) 

767 

391 

190 

82 

(a) 

5.49E+7 

1.32E+7 

3.04E+6 

2.47E+5 

5.06E+4 

2.43E+4 

1.29E+4 

2.68E+3 

1080 

543 

235 

92 

a The 4-day dose does not exceed the PAG outside the 2-mile radius of the accident site. 

The total cost of evacuation within this radius is 2.02E+5 dollars;. the total dose avoided· 

is 2.78E+3 person-rem; and the.total cost per person-rem avoided is $73. 

C-7 

Table C-2 Costs for Implementing Various PAGs for an SST-2 Type Accident (Stability Class C) 

Evacuation PAG Total Area Marginal Area 

angle 

(degrees) 

value 

(rem) Cost 

(dollars) 

Dose 

avoided 

(person-rem) 

Dollars/ 

person-rem 

avoided 

ll Cost 

(dollars) 

ll Dose 

avoided 

(person-rem) 

ll Dollars/ 

llperson-rem 

avoided 

70 0.5 

1 

2 

5 

10 

20 

50 

4.95E+7 

1.23E+7 

2.46E+6 

7.82E+5 

3.93E+5 

2.60E+5 

(a) 

1.13E+5 

6.31E+4 

3.73E+4 

2.71E+4 

2.10E+4 

1.62E+4 

(a) 

439 

195 

66 

29 

19 

16 

(a) 

3.71E+7 

9.87E+6 

1.68E+6 

3.89E+5 

1.32E+5 

3.40E+4 

4.95E+4 

2.58E+4 

1.02E+4 

6.15E+3 

4.75E+3 

2.50E+3 

750 

382 

165 

63 

28 

10 

90 0.5 

1 

2 

5 

10 

20 

50 

6.35E+7 

1.58E+7 

3.11E+6 

9.48E+5 

4.47E+5 

2.77E+5 

(a) 

1.13E+5 

6.32E+4 

3.74E+4 

2.72E+4 

2.10E+4 

1.63E+4 

(a) 

564 

250 

83 

35 

21 

17 

(a) 

4.77E+7 

1.27E+7 

2.16E+6 

5.00E+5 

1.70E+5 

3.40E+4 

4.95E+4 

2.58E+4 

1.02E+4 

6.16E+3 

4.76E+3 

2.50E+3 

964 

491 

212 

81 

36 

14 

180 0.5 

1 

2 

5 

10 

20 

50 

1.25E+8 

3.10E+7 

5.95E+6 

1.68E+6 

6.87E+5 

3.51E+5 

(a) 

1.13E+5 

6.32E+4 

3.74E+4 

2.72E+4 

2.10E+4 

1.63E+4 

(a) 

1110 

491 

159 

62 

33 

22 

(a) 

9.44E+7 

2.51E+7 

4.28E+6 

9.90E+5 

3.36E+5 

6.70E+4 

4.95E+4 

2.58E+4 

1.02E+4 

6.16E+3 

4.77E+3 

2.50E+3 

1910 

971 

419 

161 

70 

27 

a The 4-day dose does not exceed the PAG outside the 2-mile radius of the accident site. 

The total cost of evacuation within this radius is 2.02E+5 dollars; the total dose avoided 

is 2.78E+3 person-rem; and the total cost per person-rem avoided is $73. 

C-8 

Table C-3 Costs for Implementing Various PAGs for an SST-2 Type Accident (Stability Class F) 

Evacuation PAG Total Area Marginal Area 

angle 

(degrees) 

value 

(rem) Cost 

(dollars) 

Dose 

avoided 

(person-rem) 

Dollars/ 

person-rem 

avoided 

A Cost 

(dollars) 

A Dose 

avoided 

(person-rem) 

A Dollars/ 

A person-rem 

avoided 

70 0.5 

1 

2 

5 

10 

20 

50 

8.95E+7 

4.95E+7 

2.83E+7 

1.23E+7 

6.68E+6 

3.65E+6 

1.49E+6 

4.61E+5 

4.41E+5 

4.19E+5 

3.83E+5 

3.53E+5 

3.22E+5 

2.68E+5 

194 

112 

67 

32 

19 

11 

5.6 

4.01E+7 

2.12E+7 

1.59E+7 

5.65E+6 

3.03E+6 

9.70E+5 

1.98E+4 

2.17E+4 

3.66E+4 

2.93E+4 

3.18E+4 

3.10E+4 

2020 

977 

436 

193 

95 

32 

90 0.5 

1 

2 

5 

10 

20 

50 

1.15E+8 

6.35E+7 

3.63E+7 

1.58E+7 

8.54E+6 

4.64E+6 

1.86E+6 

4.61E+5 

4.41E+5 

4.19E+5 

3.83E+5 

3.53E+5 

3.22E+5 

2.68E+5 

250 

144 

87 

41 

24 

14 

6.9 

5.15E+7 

2.72E+7 

2.05E+7 

7.26E+6 

3.90E+6 

1.30E+6 

1.98E+4 

2.17E+4 

3.66E+4 

2.93E+4 

3.18E+4 

3.10E+4 

2600 

1260 

560 

248 

123 

41 

180 0.5 

1 

2 

5 

10 

20 

50 

2.27E+8 

1.25E+8 

. 7.16E+7 

3.10E+7 

1.67E+7 

8.98E+6 

3.51E+6 

4.61E+5 

4.41E+5 

4.19E+5 

3.83E+5 

3.53E+5 

3.22E+5 

2.68E+5 

493 

285 

17l 

81 

47 

28 

13 

1.02E+8 

5.39E+7 

4.05E+7 

1.44E+7 

7.71E+6 

2.40E+6 

1.99E+4 

_ 2.17E+4 

3.66E+4 

2.92E+4 

. 3.18E+4 

3.10E+4 

5120 

2480 

1110 

492 

242 

80 

C-9 

durations not exceeding a few hours 

and where reliable wind direction 

forecasts are available. 

0.2.1.3 Conclusions 

As shown in Tables C-1, C-2, and 

C-3 for an SST-2 accident, the cost per 

unit dose avoided is greatest for wide 

angle evacuation and for the most 

stable conditions, class (F). Although a 

few emergency plans call for evacuation 

over wider angles (up to 360 degrees), 

the model shown in Figure C-1 with a 

90 degree angle is most common. 

To estimate an upper bound on dose 

for evacuation based on cost, we first 

consider common values placed on 

avoiding risk. As one input into its 

risk management decisions, EPA has 

used a range of$400,000 to $7,000,000 

as an acceptable range of costs for 

avoiding a statistical death from 

pollutants other than radiation. For a 

risk of 3x10.4 cancer deaths per 

person-rem (see Appendix B), these 

dollar values are equivalent to a range 

of from about $120 to $2,000 per 

person-rem avoided. These values can 

be compared to the marginal 

cost-effectiveness (dollars per 

person-rem) of evacuation over an 

angle of 90 degrees. The resulting 

ranges of upper bounds on dose are 

shown in Table C-4 for SST-1, SST-2, 

and SST-3 accident scenarios. The 

maximum upper bounds (based on 

minimum costs for avoiding risk) range 

from 1 to 10 rem, with most values 

being approximately 5 rem. The 

minimum upper bounds (based on 

maximum costs for avoiding risk) range 

from 0.15 to 0.8 rem, with 0.5 rem 

being representative ofmost situations. 

From these data we conclude that, 

based on the cost of evacuation, a P AG 

larger than the range ofvalues 0.5 to 5 

rem would be incompatible with 

Principle 3. 

C.2.2 Risk ofEvacuation 

Principle 4 requires that the risk of 

the protective action not exceed the 

risk associated with the dose that will 

be avoided. Risk from evacuation can 

come from several sources, including 

(1) transportation incidents for both 

pedestrians and vehicle passengers, (2) 

exposure to severe weather conditions 

or a competing disaster, and (3), in the 

case of immobile persons, anxiety, 

unusual activity, and separation from 

medical care or services. The first 

source, transportation incidents, is the 

only category for which the risk has 

been quantified. An EPA report 

(HA-75) evaluated the risk of 

transportation fatalities associated 

with emergency evacuations that have 

actually occurred and concluded that 

the risk of death per mile traveled is 

about the same as that for routine 

automobile traveL Using this as a 

basis, the risk of death from travel is 

about 9x1o-s deaths per person-mile, or 

9x10.6 deaths per person for the 

100-mile round trip assumed for 

evacuation. Assuming a risk of fatal 

cancer from radiation of approximately 

3x10.4 per person-rem; such an 

evacuation risk is equivalent to a dose 

of about 0.03 rem. 

C-10 

Table C-4 Upper Bounds on Dose for Evacuation, Based on the Cost of Avoiding Fatalitiesa 

Accident 


Category 


SST-1 


SST-2 


SST-3 


Atmospheric 


Stability Class 


A 

c 

F 

A 

c 

F 

A 

c 

F 

Dose Upper Boundsb,c 

Maximum . Minimum 

(rem) . (rem) 

5 0.4 

5 0.4 

10 0.8 

1 0.15 

3.5 0.25 

10 0.7 

(d) (d) 

(d) (d) 

5 0.45 

a Based on data from EP-87a. 

b Windspeeds typical of each stability class were chosen. 

c Based on an assumed range of $400,000 to $7,000,000 per life saved. 

d For stability classes A and C, the dose from an SST-3 accident is not predicted to exceed 0.5 rem 

outside a 2-mile radius. It is assumed that evacuation inside this radius would be carried out 

based on the emergency condition on the site. No differential evacuati9n costs were calculated 

within this area. 

\ 

In comparing this risk (or, more 

exactly, its equivalent in dose) to the 

risk avoided by evacuation, it is 

important to note that protective action 

must be implemented over a larger 

population than will actually be 

exposed at the level of the PAG. 

Because of uncertainty or 

unpredictable changes in wind 

direction, the exact location of the 

plume will not be precisely known. 

Dose projections are made for the 

maximum exposed individuals - those 

at the assumed location of the plume 

centerline. To assure. that these 

individuals will be protected, it is 

necessary that others on either side 

take protective action at exposures that 

are less than at the plume centerline, 

and, in some cases, are zero. Thus, the 

entire evacuated population could 

incur, on the average, a risk from the 

protective action which exceeds the risk 

of the radiation dose avoided. 

Although it is not possible to assure 

that no individuals incur risks from 

evacuation greater than their radiation 

risks, we can assure that this does not 

C-11 

occur, on the average, at the outer 

margin of the evacuation area. For 

this reason, we also examined the 

average dose avoided for the 

incrementally evacuated population for 

various choices of evacuation levels. 

Table C-5 presents the results, which 

are derived from the data in Tables 

C-1, C-2, and C-3. For the levels 

analyzed, the average dose avoided is 

always significantly greater than 0.03 

rem. We conclude, therefore, that the 

choice of PAGs will not be influenced 

by Principle 4, for persons in the 

general population whose risk from 

evacuation is primarily the normal risk 

oftransportation, ifthe centerline dose 

avoided is at or above 0.5 rem. 

As previously discussed, hazardous 

environmental conditions (e.g., severe 

weather or a competing disaster) could 

create transportation risks from 

evacuation that would be higher than 

normal. It is therefore appropriate to 

make an exception to allow higher 

projected doses for evacuation decisions 

under these circumstances. In the 

absence of any definitive information 

on such higher risks from evacuation, 

we have arbitrarily assumed that it 

would be appropriate to increase the 

Table C-5 Average Dose Avoided per Evacuated Individual for Incremental Dose 

Levels for Evacuation 

Centerline dose 


(rem) 


0.5 to 1 


1 to 2 


2 to 5 


5 to 10 


recommended projected dose for 

evacuation of the general population 

under hazardous environmental 

conditions up to a factor of 5 higher 

than that used under normal 

environmental conditions. 

It is also recognized that those 

persons who are not readily mobile are 

Average dose avoided (rem per 

individual) by stability class 

A c F 

0.34 0.19 0.07 

0.67 0.38 0.15 

0.87 0.33 

0.75 

at higher risk from evacuation than are 

average members ofthe population. It 

would be appropriate to adopt higher 

PAGs for evacuation ofindividuals who 

would be at greater risk from 

evacuation itself than for the typically 

healthy members of the population, 

who are at low risk from evacuation. 

In the absence ofdefinitive information 

C-12 

on the higher risk associated with the 

evacuation of this group, we have 

arbitrarily assumed that it is 

appropriate to adopt PAGs a factor of 

five higher for evacuation of high risk 

groups under normal environmental 

conditions. If both conditions exist, 

(high risk groups and hazardous 

environmental conditions) projected 

doses up to 10 times higher than the 

P AGs for evacuation of the general 

population under normal conditions 

may be justified. These doses are 

expected to satisfy Principle 4 without 

violating Principles 1 and 3. Although 

they violate Principle 2, Principle 4 

becomes, for such cases, the overriding 

consideration. 

C.2.3 Thyroid Blocking 

The ingestion of stable potassium 

iodide (KI) to block the uptake of 

radioiodine by the thyroid has been 

identified as an effective protective 

action. The Food and Drug 

Administration (FDA) analyzed 

available information .on the risk of 

radioiodine-induced thyroid cancers 

and the incidence and severity of side 

effects from potassium iodide (FD-82). 

They concluded " ... risks from the 

short-term use of relatively low doses 

ofpotassium iodide for thyroid blocking 

in a radiation emergency are 

outweighed by the risks of 

radioiodine-induced thyroid nodules or 

cancer at a projected dose to the 

thyroid gland of 25 rem. FDA 

recommends .that potassium iodide in 

doses of 130 milligrams (mg) per day 

for adults and children above 1 year 

and 65 mg per day for children below 1 

year of age be considered for thyroid 

blocking in radiation emergencies in 

those persons who are likely to receive 

a projected radiation dose of 25 rem or 

greater to the thyroid gland from 

radioiodines released into the 

environment. . To have the greatest 

effectin decreasing the accumulation of 

radioiodine in the thyroid gland, these 

doses ·of potassiu,m iodide ·should be 

administered immediately before or 

after exposure. If a person is exposed 

to radioiodine when cirCUilistances do 

not permit the immediate 

administration ofpotassium iodide, the 

initial administration will still have 

substantial benefit even ifit is taken 3 

or 4 hours ·after acute exposure". 

Evacuation and sheltering are, 

however, preferred alternatives for 

most situations because .they provide 

protection for the whole body . 

and avoid the risk ofmisapplication of 

potassium iodide. 

The Federal Emergency 

Management Agency ha$ published a 

Federal policy developed by the Federal 

Radiological Preparedness Coordinating 

Committee regarding the use of KI as 

a protective· action (FE-85). In 

summary, the policy recommends the 

stock-piling of KI and distribution 

during emergencies to emergency 

workers and institutionalized persons, 

but does not recommend. requiring 

stockpiling or distribution to the 

general public. The policy recognizes, 

however, that options on the 

distribution and use of KI rests with 

the States and, hence, the policy 

statement pernrits State and local 

governments, within the limits oftheir 

authority, to; take measures beyond 

C-13 

those recommended or required 

nationally. 

C.2.4 Sheltering 

Sheltering means staying inside a 

structure with doors and windows 

closed and, generally, with exterior 

ventilation systems shut off. 

Sheltering in place (i.e. at or near the 

location of an individual when the 

incident occurs) is a lowMcost, lowMrisk 

protective action that can provide 

protection with an efficiency ranging 

from almost 100 percent to zero, 

depending on the circumstances. It can 

also be particularly useful to assure 

that a population is positioned so that, 

ifthe need arises, communication with 

the population can be carried out 

expeditiously. The degree ofprotection 

provided by a structure is governed by 

attenuation of radiation by structural 

components (themass ofwalls, ceilings, 

etc.) and by its outside/inside airexchange rate. These two protective 

characteristics are considered 

separately. 

The protection factor may be 

characterized by a dose reduction factor 

(DRF), defined as: 

DRF = dose with protective action 

dose without protective action 

The shielding characteristics of most 

structures for gamma radiation can be 

categorized based on whether they are 

"small" or lflarge." Small structures are 

primarily single-family dwellings, and 

large structures include office, 

industrial, and commercial buildings. 

The typical attenuation factors given in 

Table C-6 show the importance of the 

type of structure for protection from 

external gamma radiation (EP-78a). If 

the structure is a wood frame house 

without a basement, then sheltering 

from gamma radiation would provide a 

DRF of 0.9; i.e., only 10 percent of the 

dose would be avoided. The DRFs 

shown in Table C-6 are initial values 

prior to infiltration of contaminated 

air, and therefore apply only to short 

duration plumes. The values will 

increase with increasing time of 

exposure to a plume because of the 

increasing importance ofinside-outside 

air exchange. However, this reduction 

Table C-6 Representative Dose Reduction Factors for External Radiation 

Structure 


Wood frame house (first floor) 


Wood frame house (basement) 


Masonry house 


Large office or industrial building 


DRF 

0.9 

0.6 

0.6 

0.2 or less 

Effectiveness 

(percent) 

10 

40 

40 

80 or better 

C-14 

in efficiency is not dramatic for source 

terms involving primarily gamma 

radiation, because most of the dose 

arises from outside, not from the small 

volume of contaminated air inside a 

shelter. Therefore, most shelters will 

retain their efficiency as shields 

against gamma radiation, even if the 

concentration inside equals the 

concentration outside. 

The second factor is the 

inside/outside air exchange rate. This 

factor primarily affects protection 

against exposure by inhalation of 

airborne radionuclides with half lives 

long compared to the air exchange rate. 

The factor is expressed as the number 

of air exchanges per hour, L (h"1), or 

the volume offresh air flowing into and 

out ofthe structure per hour divided by 

the volume of the structure. Virtually 

any structure that can be used for 

sheltering has some degree of 

outside/inside air exchange due to 

natural ventilation, forced ventilation, 

or Uncontrollable outside forces, 

primarily wind. 

Assuining constant atmospheric and 

source conditions and no effects from 

filtration, deposition, or radioactive 

decay, the following model can be used 

to estimate the buildup of indoor 

concentration of radioactivity, for a 

given outdoor concentration, as a 

function oftime after appearance ofthe 

plume and of ventilation rate: 

where ci = concentrati-?n inside, 

Co = concentration outside, 

L = ventilation rate (h-1

), and 

t =elapsed time (h). 

Typical values for ventilation rates 

range from one-fifth to several air 

exchanges pet hour. In the absence of 

measurements, an air exchange rate of 

1.0/h. may be assumed for structures 

with no special preparation except for 

closing the doors and windows. An air 

exchange rate of 0.3/h. is appropriate 

for relatively air-tight structures, such 

as well-sealed residences, interior 

rooms with doors chinked and no 

windows, or large structures with 

ventilation sQ.ut off. Using the above 

model to calculate indoor concentration 

relative to outdoor concentration after 

one, two, and four complete air 

exchanges, the indoor concentration 

would be about 64 percent, 87 percent, 

and 98 percent of the outside 

concentration, respectively. It is 

apparent that staying in a shelter for 

more time than that required for one or 

two complete air exchanges is not very 

effective for reducing inhalation 

exposure. 

The inhalation DRF is equal to the 

ratio of the average inside to outside 

air concentration over the period of 

sheltering. Studies have been 

conducted of:typical ventilation rates 

for dwellings (EP-78a) and for large 

commercial structures (GR-86). In 

each case the rate varies according to 

the air tightness of the structure, 

windspeed, and the indoor-to-outdoor 

temperature , difference. For the 

purpose of deriving P AGs, average 

ventilation rates were chosen for the 

two types of structures that are of 

C-15 

greatest interest. Table C-7 shows than a 10 percent increase in the dose 

calculated dose reduction factors for received during plume passage, 

inhalation exposure as a function of (EP-78b)), but can be greater for 

plume duration, for beta-gamma source inhalation dose. 

terms, assuming average ventilation 

rates for these structures. Doses from inhalation during 

sheltering can be reduced in several 

A potential problem with sheltering ways, including reducing air exchange 

is that persons may not leave the rates by sealing cracks and openings 

shelter as soon as the plume passes with cloth or weather stripping, tape, 

and, as a result, will receive exposure etc., and filtering the inhaled air with 

from radioactive gases trapped inside. commonly available items like wet 

The values for DRFs tabulated in Table towels and handkerchiefs. Analyses for 

C-7 ignore this potential additional some hypothesized accidents, such as 

contribution. This effect is generally short-term transuranic releases, show 

minor for gamma dose (generally less that sheltering in residences and other 

Table C-7 	 Dose Reduction Factors for Sheltering from Inhalation of Beta-Gamma 

Emitters 

Ventilation rate Duration of 

(air changes/h) plume exposure(h) DRF 

0.311 0.5 	 0.07 

1 	 0.14 

2 	 0.25 

4 	 0.41 

6 	 0.54 

l.Ob 	 0.5 0.21 

1 	 0.36 

2 	 0.56 

4 	 0.75 

6 	 0.83 

•Applicable to relatively "airtight" structures such as well- sealed residences, interior rooms with 

chinked doors and no windows, or large structures with outside ventilation shut off. 

bApplicable to structures with no special preparation except for closing of doors and windows. 

C-16 

buildings can be more effective than for 

beta-gamma emitters, may provide 

adequate. protection, and may be more 

effective than evacuation when 

evacuation cannot be completed before 

plume arrival (D0-90). However, 

sheltering effectiveness for the 

inhalation exposure pathway can be 

reduced drastically by open windows 

and doors or by forced air ventilation. 

Therefore, reliance on protection 

assumed to be afforded based on large 

dose reduction factors for sheltering 

should be accompanied by cautious 

examination of , possible failure 

mechanisms, and, except in very 

unusual circumstances, should not be 

relied upon at projected doses greater 

than 10 rem. Such analysis should be 

based on realistic or "best estimate" 

dose models and include consideration 

of unavoidable dose if evacuation were 

carried out. 

C.3 Recommended PAGs for Exposure 

to a Plume during the Early Phase 

The four principles which fonn the 

basis for the selection of PAG values 

are presented in Chapter 1. The risks 

ofhealth effects from radiation that are 

relevant to satisfying Principles 1 and 

2 are presented in Appendix B and 

analyses of the costs and risks 

associated with evacuation relative to 

Principles 3 and 4 have been presented 

in this appendix. These results, for 

application to the early phase, are 

summarized in Table C-8. 

The following describes how these 

results lead to the selection of the 

P AGs. Conformance to Principle 1 

(avoidance of acute health effects) is 

assured by the low risk required to 

satisfy Principle 2, and thus requires 

no additional·consideration. Principle 

2 (acceptable risk of delayed health 

effects) leads to the choice of0.5 rem as 

an upper bound on the avoided dose 

below which evacuation of the general 

population is justified under normal 

conditions. This represents a risk of 

about 2E-4 of fatal cancer. Maximum 

lifetime risk levels considered 

acceptable by EPA from routine 

operations of individual sources range 

from 1E-6 to 1E-4. Risk levels that are 

higher than this must be justified on 

the basis of the emergency nature of a 

situation. In this case, we judge that 

up to an order of magnitude higher 

combined risk from all phases of an 

incident may be justifiable. The choice 

of 0.5 rem avoided dose as an 

appropriate criterion for an acceptable 

level ofrisk during the early phase is a 

subjective judgment that includes 

consideration. of possible contributions 

from exposure during other phases of 

the incident, as well as the possibility 

that risk estimates may increase 

moderately in the near future as a 

result of current reevaluations of 

radiation risk. 

Principle 4 (risk from the protective 

action must be less than that from the 

radiation risk avoided) supplies a lower 

bound of0.03·rem on the dose at which 

evacuation of most members of the 

public is justified. Finally, under 

Principle 3 (cost/risk considerations) 

evacuation is justified only at values 

equal to or greater than 0.5 rem. This 

will be limiting unless lower values are 

required for purely health-based 

C-17 

Table C-8 Summary of Considerations for Selecting the Evacuation PAGs. 

Dose 

(rem) Consideration Principle Section 

50 	 Assumed threshold for acute 

health effects in adults. 1 B.2.1.4 

10 	 Assumed threshold for acute 

health effects in the fetus. 1 B.2.1.4 

5 	 Maximum acceptable dose for normal 

occupational exposure of adults. 2 C.5 

5 	 Maximum dose justified to average 


members of the population, based 


on the cost of evacuation. 
 3 C.2.1.3 

0.5 	 Maximum acceptable dose to the 

general population from all 

sources from nonrecurring, nonaccidental exposure. 2 B.4.4 

0.5 	 Minimum dose justified to average 

members of the population, based 

on the cost of evacuation. 3 C.2.1.3 

0.5 	 Maximum acceptable dosea to 

the fetus from occupational 

exposure of the mother. 2 C.5 

0.1 	 Maximum acceptable dose to the 

general population from all 

sources from routine (chronic), 

nonaccidental exposure. 2 B.4.4 

0.03 	 Dose that carries a risk assumed 

to be equal to or less than that 

from evacuation. 4 C.2.2 

vrhis is also the dose to the 8- to 15-week-old fetus at which the risk ofmental retardation is assumed 

to be equal to the risk offatal cancer to adults from a dose of 5 rem. 

C-18 

reasons (Principle 2). But this is not 

the case. The single lower purely 

health-based value, 0.1 rem, is only 

valid as a health-based criterion for 

chronic exposure. 

In summary, we have selected the 

value 0.5 rem as the avoided dose 

which justifies evacuation, because 1) it 

limits the risk of delayed effects on 

health to levels adequately protective of 

public health under emergency 

conditions, 2) the cost of 

implementation of a lower value is not 

justified, and 3) it satisfies the two 

bounding requirements to avoid acute 

radiation effects and to avoid 

increasing risk through the protective 

action itself. We note that this choice 

also satisfies the criterion for 

acceptable risk to the fetus of 

occupationally exposed mothers (as 

well as falling well below dose values 

at which abortion is recommended). 

As noted in Section C.2.4, we 

assume that the dose normally 

avoidable by evacuation (the dose that 

is not avoided by the assumed 

alternative of sheltering) is one half of 

the projected dose. The value of the 

P AG for evacuation of the general 

public under normal circumstances is 

therefore chosen as one' rem projected 

.§.!:!:!!! of the committed effective dose 

equivalent from inhalation of 

radionuclides and effective dose 

equivalent from exposure to external 

radiation. 

The above considerations apply to 

evacuation of typical members of the 

population under normal 

circumstances, and apply to effective 

doses (i.e. the weighted sum ofdoses to 

all organs). As discussed in previous 

sections, it may be appropriate to 

further limit dose to the thyroid and 

skin, to adjust the value for special 

groups of the population at unusually 

high risk from evacuation, and to 

provide for situations in which the 

general population may be at higher 

than ·normal risk from evacuation. 

These are addressed, in turn, below. 

In the case of exposure of the 

thyroid to radioiodine, action based 

solely on effective dose would not occur 

until a thyroid dose about 33 times 

higher than the corresponding effective 

dose to the entire body. As noted in 

Section B.4.1.1, because the weighting 

factor for thyroid used to calculate 

effective dose. does not reflect the high 

ratio ofcurable to fatal thyroid cancers, 

protective action to limit dose to the 

thyroid is recommended at a thyroid 

dose 5 times the numerical value ofthe 

PAG. 

Similarly, .since effective dose does 

not include dose to the skin, and for 

other reasons discussed in Section 

B.4.1.2, protective action to limit dose 

to skin is recommended at a skin dose 

50 times the numerical value of the 

P AG. As in. the case of the thyroid, 

this includes .consideration of the risk 

ofboth curable and noncurable cancers. 

Special risk groups include fetuses, 

and persons who are not readily 

mobile. As noted in Sections B.4.1.3 

and B3, we assume that the risk of 

radiation-induced cancer is about 5 to 

10 times higher for fetuses than for 

adults and that the risk of mental 

C-19 

retardation in fetuses exposed during 

the 8th to 15th weeks of gestation is 

about 10 times higher than the risk of 

fatal cancer in equivalently exposed 

adults. However, due to the difficulty 

of rapidly evacuating only pregnant 

women in a population, and the 

assumed higher-than-average risk 

associated with their evacuation, it is 

not considered appropriate to establish 

separate PAGs for pregnant women. 

We note that the PAG is chosen 

sufficiently low to satisfy Federal 

guidance for limiting exposure of the 

fetus in pregnant workers. 

Higher PAGs for situations 

involving higher risks from evacuation 

were discussed in Section C.2.2. Under 

normal, low-risk, environmental 

conditions, P AGs for evacuation of 

groups who present higher than 

average risks from evacuation (e.g., 

persons who are not readily mobile) are 

recommended at projected doses up to 

5 rem. Evacuation of the general 

population under high-risk 

environmental conditions is also 

recommended at projected doses up to 

5 rem. If evacuation of high risk 

groups underhazardous environmental 

conditions is being considered, 

projected doses up to 10 rem may, 

therefore, be justified. 

Short-term sheltering is recognized 

as a low-cost, low-risk, protective action 

primarily suited for protection from 

exposure to an airbome plume. 

Sheltering will usually be clearly 

justified to avoid projected doses above 

0.5 rem, on the basis of avoidance of 

health risks. However, data are not 

available to establish a lower level at 

which sheltering is no longer justified 

because of its cost or the risk 

associated with its implementation. 

Sheltering will usually have other 

benefits related to emergency 

communication with members of the 

public. It is expected that protective 

action planners and decision 

authorities will take into account the 

added benefits of sheltering (e.g., 

communication and established 

planning areas) for decisions on 

sheltering at levels below 0.5 rem. 

Bathing and changing of clothing 

are effective for reducing beta dose to 

the skin of persons exposed to an 

airborne plume of radioactive 

materials. Since these are also 

low-cost, low-risk actions, no PAG is 

recommended for initiating their 

implementation. It is expected that 

any persons exposed in areas where 

evacuation is justified based on 

projected dose from inhalation will be 

routinely advised by emergency 

response officials to take these actions 

within 12 hours after exposure. 

The use of stable iodine to protect 

against uptake of inhaled radioiodine 

by the thyroid is recognized as an 

effective altemative to evacuation for 

situations involving radioiodine 

releases where evacuation cannot be 

implemented. If procedures are 

included in the applicable emergency 

response plan, use of stable iodine 

should be considered for any such 

situation in which evacuation or 

sheltering will not be effective in 

preventing thyroid doses of 25 rem (see 

also C.2.3). 

C-20 

C.4 Comparison to Previous PAGs 

This section compares the level of 

protection provided by the previously 

published P AGs for evacuation (one 

rem external gamma dose from the 

plume and 5 rem committed dose to the 

thyroid from inhalation, under normal 

evacuation circumstances) with this 

P AG. The effective dose addressed by 

this PAG, as well as skin,. thyroid, and 

external gamma doses from the plume 

during the early phase from the three 

major exposure pathways for an 

airborne. release were calculated for 

radionuclide mixes postulated for three 

nuclear power plant accident 

sequences. The doses were then 

normalized for each accident so that 

they represent a location in the 

environment where the controlling dose 

would be equal to the current PAG. 

These results are shown in Table C-9. 

Based on the results shown in Table 

C-9, the following conclusions are 

Table C-9. Comparison of Projected Doses for Various Reactor Accident Scenariosa 

Accident Effective dose Skin dosed Thyroid dosee External 

categori' equivalentc (rem) (rem) doser 

(rem) (rem) 

SST-1 0.7 6 5 0.02 

SST-2 1 5 5. 0.4 

SST-3 0.4 6 5 0.1 

3

Doses are normalized to the limiting PAG. 


bSee Table E-1 for a description of these accident scenarios. 


'The dose is the sum of doses from 4-day exposure to external gamma radiation from deposited 


materials, external exposure to the plume, and the committed effective dose equivalent from 


inhalation of the plume. 


~he dose equivalent fro~ external beta radiation from the plume and from 12 hours exposure to 


materials deposited on skin and clothing. 


ecommitted dose equivalent to the thyroid from inhalation. 

rExternal gamma dose equivalent from the plume. 

C-21 

apparent, for the accident sequences 

analyzed: 

1. The PAG for the thyroid is 

controlling for all three accident 

categories. For the SST-2 category, 

effective dose is also controlling. 

Thus,application of the previous P AG 

(5 rem) for thyroid would provide the 

same protection as the revised P AG for 

all three accident categories. 

2. Skin doses will not be controlling 

for any of the accident sequences (if 

bathing and change of clothing is 

completed within 12 hours of plume 

passage, as assumed). 

3. Gamma dose from direct exposure 

to the plume is small compared to the 

effective dose from the three major 

exposure pathways combined. 

In summary, for the accident 

sequences analyzed, the old PAGs 

provide the same level of protection as 

the new PAGs. For releases that 

contain a smaller fraction radioiodines 

than these accident scenarios the new 

P AGs are slightly more protective. 

C.5 Dose Limits for Workers 

Performing Emergency Services 

Dose limits for workers during 

emergencies are based on avoiding 

acute health effects and limiting the 

risk of delayed health effects, in the 

context ofthe need to assure protection 

of the population and of valuable 

properties. It is assumed that most 

such workers are accustomed to 

accepting an element of risk as a 

condition of their employment. 

Examples of occupations that may be 

affected include law enforcement, 

firefighting, radiation protection, civil 

defense, traffic control, health services, 

environmental monitoring, animal care, 

and transportation services. In 

addition, selected workers at utility, 

industrial, and at farms and other 

agribusinesses may be required to 

protect others, or to protect valuable 

property during an emergency. The 

above are examples -- not designations 

-- of worRers that may be exposed to 

radiation during emergencies. 

Radiation exposure of workers 

during an emergency should normally 

be govemed by the Federal Radiation 

Protection Guidance for Occupational 

Exposure (EP-87). This guidance 

specifies an upper bound of five rem 

committed effective dose equivalent per 

year for most workers. (Pregnant 

women, who, under this guidance 

should not normally engage in work 

situations that involve more than 

approximately 50 mrem/month, would 

normally be evacuated as part of the 

general population.) The guidance also 

specifies that doses to workers should 

be maintained as low as reasonably 

achievable; that doses should be 

monitored; and that workers should be 

informed of the risks involved and of 

basic principles for radiation 

protection. 

There are some emergency 

situations, however, for which higher 

doses may be justified. These include 

lifesaving operations and the protection 

of valuable property. Intemational 

guidance (IC-77) recognizes two 

C-22 

additional dose levels for workers 

under speciallyjustified circumstances: 

two times the annual limit for any 

single event, and five times the annual 

limit in a lifetime. The dose limits 

recommended here adopt the former 

value (10 rem) for operations limited to 

the protection of valuable property. 

The latter value (25 rem) may be 

permitted for situations involving 

lifesaving operations or activities that 

are essential to preventing substantial 

risks to populations. In this context 

IIsubstantial risksII means collective 

doses that are significantly larger than 

those incurred through the protective 

activities engaged in by the workers. 

Workers should not operate under dose 

limits higher than five rem unless the 

following conditions are satisfied: 

1. Lower doses through the rotation of 

workers or other commonly-used dose 

reduction methods are not possible, 

and 

2. Instrumentation is available to 

measure their exposure. 

In addition to the limitation on 

effective dose equivalent, the dose 

equivalent received in any year by 

workers under normal occupational 

conditions is limited to 15 rem to the 

lens ofthe eye and 50 rem to any other 

organ, · tissue (including skin), or 

extremity of the body. (Extremity is 

defined as the forearms and hands or 

the lower legs and feet (EP-87).) By 

analogy to these dose limits for organs 

and extremities, the limits for workers 

performing the various categories of 

emergency services are established at 

numerical values that are 5 times the 

limits for effective dose to the lens of 

the eye and 10 times the limits for 

effective dose to any other organ, tissue 

(including skin), or extremity of the 

body. 

Situations may occur in which a 

dose in excess of 25 rem would be 

required for lifesaving operations. It is 

not possible to prejudge the risk that 

one person should be allowed to take to 

save the life of another. However, 

persons undertaking an emergency 

mission in which the dose would exceed 

25 rem to the whole body should do so 

only on a voluntary basis and with full 

awareness of the risks involved, 

including the numerical levels . of dose 

at which acute effects of radiation will 

be incurred and numerical estimates of 

the risk of delayed effects. 

The risk of acute health effects is 

discussed in B.2. Table C-10 presents 

estimated cancer mortality rates for a 

dose of 25 rem, as a function of age at 

the time of exposure. The risk of 

cancer from moderately higher doses 

will increase proportionately. These 

values were . calculated using risk 

estimates from BEIR-3 (NA-80) as 

discussed in Section B.4, and life table 

analyses that assume the period of 

·cancer risk lasts for ·the worker's 

lifetime (BU-81). The risk was 

calculated for the midpoint of each age 

range. Roughly equivalent risks of 

nonfatal cancer and serious genetic 

effects (if gonadal tissue is exposed) 

will also be incurred. · 

The dose limits of 75 rem to the 

whole body previously recommended by 

EPA and 100 rem that has been 

C-23 

recommended by NCRP (GL-57) for 

lifesaving action represents a very high 

level of risk of acute and delayed 

health effects. A dose of 100 rem is 

expected to result in an approximately 

15 percent risk of temporary incapacity from nonlethal acute effects and 

an indeterminate, but less than 5 

percent, chance of death within 60 

days. This is in addition to a risk of 

about 1 in 30 of incurring fatal cancer. 

Such high risk levels can only be 

accepted by a recipient who has been 

made aware of the risks involved. 

Therefore, no absolute dose limit for 

lifesaving activities is offered. 

Table C-10 Cancer Risk to Emergency Workers Receiving 25 Rem Whole Body 

Dose 

Age ofthe Approximate risk 

emergency of premature death 

worker at time (deaths per 1,000 

of exposure persons exposed) 

(years) 

20 to 30 9.1 

30 to 40 7.2 

40 to 50 5.3 

50 to 60 3.5 

References 

BU-81 Bungert B.M.t J.R. Cookt 

and M.K. Barrick. Life Table Methodology 

for Evaluating Radiation Risk - An 

Application Based on Occupational 

Exposures. Health Physics 40 (1981):439­

455. 

D0-90 U . S . D e p a r t m e n t o f 

Energy. Effectiveness of Sheltering in 

Average years of 


life lost if 


premature death 


occurs 


(years) 


24 


19 

15 

11 

Buildings and Vehicles for Plutonium. 

DOE/EH-0159, U.S. Department of Energy, 

Washington (1990). 

EP-78a U.S. Environmental Protection 

Agency. Protective Action Evaluation Part I 

- The Effectiveness of Sheltering as a 

Protective Action Against Nuclear Accidents 

Involving Gaseous Releases. EPA 

520/1-78-001A, U.S. Environmental 

Protection Agency, Washington (1978). 

C-24 

EP-78b U.S. Environlll.ental Protection 

Agency. Protective Action Evaluation Part 

II - Evacuation and Sheltering as Protective 

Actions Against Nuclear Accidents 

Involving Gaseous Releases. EPA 

520/1-78-001B, U.S. Environmental 

Protection Agency, Washington (1978). 

EP-87 U.S. Environmental Protection 

Agency. Radiation Protection Guidance to 

Federal Agencies for Occupational Exposure. 

Federal Register,.Q6 2822; January 27, 1987. 

EP-87a U.S. Environmental Protection 

Agency. An Analysis of Evacuation Options 

for Nuclear Accidents. EPA 520/1-87-023, 

U.S. Environmental Protection Agency, 

Washington (1987). 

FD-82 Food and Drug Administration. 

Potassium Iodide as a Thyroid-Blocking 

Agent: in a Radiation Emergency: Final 

Recommendations On Use. Federal Register, 

47, 28158- 28159; June 29, 1982. 

FE-85 F e d e r a 1 E m e r g e n c y 

Management Agency. Federal Policy on 

Distribution of Potassium Iodide Around · 

Nuclear Power Sites for use as a Thyroidal 

Blocking Agent. Federal Register,50, 30256; 

July 24, 1985. 

FR-64 Federal Radiation Council. 

Radiation Protection Guidance for Federal 

Agencies. Fed~ral Register,~ 12056-12057; 

August 22, 1964. 

FR-65 Federal Radiation Council. 

Radiation Protection Guidance for Federal 

Agencies. Federal Register, QQ. 6953-6955; 

May 22, 1965. · 

GL-57 Glasstone, S. The Effects of 

Nuclear Weapons. U.S. Atomic Energy 

Commission, Washington (1957). 

GR-86 Grot, R.A and AK Persily. 

Measured Air Infiltration Rates in Eight 

Large Office Buildings. Special Technical 

Publication 904, American Society for Testing 

and Materials, Philadelphia {1986). 

IC-77 International Commission on 

Radiological Protection. Radiological 

Protection, ICRP Publication 26, Pergamon 

Press, Oxford (1977). 

NA-80 National Academy of Sciences. 

The Effects on Populations of Exposure to 

Low Levels of Ionizing Radiation: 1980. 

Reports of the Committee on the Biological 

Effects of Ionizing Radiations. National 

Academy Press, Washington (1980). 

C-25 


APPENDIXD 

Background for Protective Action Recommendations: 


Accidental Radioactive Contamination of 


Food and Animal Feeds* 


*This background document concerning food and animal feeds was published by 

the Food and Drug Administration in 1982. 

APPENDIXE 

Protective Action Guides for the Intermediate Phase 


(Relocation) 


Background·Information 


Contents 

Page 

E.l Introduction E-1 


E.l.l Response Duration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . E-1 


E.1.2 Source Term . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . E-2 


E.1.3 Exposure Pathways . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . E-3 


E.1.4 Response Scenario . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . E-4 


E.2 Considerations for Establishing PAGs for the Intermediate Phase ... E-6 


E.2.1 Principles ..................................... E-8 


E.2.1.1 Cost/Risk Considerations .................. E-8 


E.2.1.2 Protection of Special Groups ............... E-ll 


E.2.2 Federal Radiation Protection Guides ................ E-12 


E.3 Dose from Reactor Incidents ...................... ·'· ...... E-12 


E.4 Alternatives to Relocation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . E-13 


E.5 Risk Comparisons . . . . . . . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . E-14 


E.6 Relocation PAG Recommendations .......................... E-15 


E.7 Criteria for Reentry into the Restricted Zone 


References .. . . ... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . E-20 


Figures 


E-1 Response Areas E-5 


E-3 Cost of Avoiding Statistical Fatalities and Exposure Rates 


E-4 Average Lifetime Risk of Death from Whole Body Radiation Dose 


Compared to the Average Risk of Accidental Death from Lifetime 


E-2 Potential Time Frame ofResponse to a Nuclear Incident .......... E-7 


Corresponding to'Various Total First Year Doses ............... E-10 


(47 years) Occupation in Various Industries ................... E-16 


iii 
Tables 


Page 


E-1 Brief Descriptions Characterizing Various Nuclear Power Plant 


Accident Types (SN-82) ................................... E-2 


E-2 Release Quantities for Postulated Nuclear Reactor Accidents . . . . . . . E-3 


E-3 Annual Doses Corresponding to 5 Rem in 50 Years . . . . . . . . . . . . . E-13 


E-4 Measure of Lifetime Risk of Mortality from a Variety of Causes . . . E-17 


E-5 	 Summary of Considerations for Selecting PAGs for Relocation . . . . E-18 


E-6 	Estimated Maximum Doses to N onrelocated Persons from Areas 


Where the Projected Dose is 2 REM ......................... E-20 


lV 
AppendixE 


· Protective Action Guides for the Intermediate Phase 


(Relocation) 


Background Information 


E.l Introduction · 

This Appendix provides · 

background information for the choice 

of Protective Action Guides (P AGs) for 

relocation and other protective actions 

to reduce exposure to deposited 

radioactive materials during the 

intermediate phase ofthe response to a 

nuclear incident. The resulting P AGs 

and associated implementing guidance 

are provided in Chapters 4 and 7, 

respectively. 

This analysis is based on the 

. assumption that an airborne plume of 

radioactive material has already passed 

over an area and left a deposit of 

radioactive material behind, or that 

such material exists from some other 

source, and that the public has already 

been either sheltered or evacuated, as 

necessary, on the basis ofPAGs for the 

early phase of a nuclear incident, as 

discussed in Chapters 2 and 5. PAGs 

for subsequent relocation of the public 

and other protective actions, as well as 

dose limits for persons reentering the 

area from which the public is relocated, 

are addressed in this Appendix. 

We first set forth the assumptions 

used to derive information pertinent to 

choosing the dose level at which 

relocation of the public is appropriate. 

This is followed by an examination of 

information relevant to· this decision~ 

and selection ofthe P AG for relocation. 

The Appendix concludes with a brief 

discussion of the basis for dose limits 

for · persons temporarily reentering 

areas from which the public has been 

relocated. · 

E.l.l Response Duration 

In order to decide whether to 

initiate relocation of the public from 

specific areas it is necessary to predict 

the dose that would be avoided. One 

factor in this prediction is the duration 

of the exposure to be avoided. 

Relocation can begin as soon as 

patterns of exposure from deposited 

radioactivity permit restricted areas to 

be identified. For the purpose of this 

analysis, relocation of persons who 

have not already been evacuated from 

the restricted zone is assumed to take 

place on the .fourth day after the 

incident. Return of evacuated persons 

to their residences outside the 

restricted zone and transition to 

relocation status of persons already 

evacuated is assumed to occur over a 

period of a week or more. 

The period of exposure avoided by 

relocation ends when the relocated 

person either returns to his property or 

is permanently resettled in a new 

E-1 

location. At the time of relocation 

decisions, it will usually not be possible 

to predict when either of these actions 

will occur. Therefore, for convenience 

of dose projection, it is assumed that 

the period of exposure avoided is one 

year and that any extension beyond 

this period will be determined on the 

basis of recovery criteria. This 

assumption corresponds to emergency 

response planning guidance by ICRP 

(IC-84) and IAEA (IA-85). 

E.1.2 Source Term 

The "source term" for this analysis 

is comprised of the quantities and 

types of particulate radioactive 

material found in the environment 

following a nuclear incident. Nuclear 

incidents can be postulated with a wide 

range of release characteristics. The 

characteristics of the source terms 

assumed for the development of these 

P AGs are those postulated for releases 

from various types of fuel-melt 

accidents at nuclear power plants 

(SN-82). Table E-1 provides brief 

descriptions of these accident types. 

Radionuclide releases have been 

estimated for the three most severe 

accident types (SST-1, SST-2, SST-3) 

based on postulated core inventories 

and release fractions (Table E-2). The 

other types (SST-4 and SST-5) would 

generally not produce offsite doses from 

exposure to deposited material 

sufficient to warrant consideration of 

relocation. 

Table E-1 	Brief Descriptions Characterizing Various Nuclear Power Plant 

Accident Types (SN-82) 

Type 	 Description 

SST-1 	Severe core damage. Essentially involves loss of all installed safety 

features. Severe direct breach of containment. 

SST-2 	Severe core damage. Containment fails to isolate. Fission product release 

mitigating systems (e.g., sprays, suppression pool, fan coolers) operate to 

reduce release. 

SST-3 	 Severe core damage. Containment fails by base-mat melt-through. All 

other release mitigation systems function as designed. 

SST-4 	Modest core damage. Containment systems operate in a degraded mode. 

SST-5 	 Limited core damage. No failures of engineered safety features beyond 

those postulated by the various design basis accidents. Containment is 

assumed to function for even the most severe accidents in this group. 

E-2 

Table E-2 Release Quantities for Postulated Nuclear Reactor Accidents 

Principal 

radionuclides Estimated quantity releaseda 

contributing (Curies) 

to dose from Half-life 

deposited (days) SST-1 SST-2 SST-3 materials 

Zr-95 6.52E+1 1.4E+6 4.5E+4 1.5E+2 

Nb-95 3.50E+1 1.3E+6 4.2E+4 1.4E+2 

Ru-103 3.95E+1 6.0E+6 2.4E+5 2.4E+2 

Ru-106 · 3.66E+2 1.5E+6 5.8E+4 5.8E+1 

Te-132 3.25 8.3E+7 3.9E+6 2.6E+3 

I-131 8.05 3.9E+7 2.6E+5 1.7E+4 

CS-134 7.50E+2 8.7E+6 1.2E+5 1.3E+2 

CS-137 1.10E+4 4.4E+6 5.9E+4 6.5E+1 

Ba-140 1.28E+1 1.2E+7 1.7E+5 1.7E+2 

La-140 1.67 1.5E+6 5.1E+4 1.7E+2 

aBased on the product of reactor inventories of radionuclides and estimated fractions released for 

three accident categories (SN-82). 

For other types of source terms, 

additional analysis may be necessary to 

assure adequate protection. For 

example, ifthe release includes a large 

proportion of long-lived radionuclides, 

doses will continue to be delivered over 

a long period of time, and, if no 

remedial actions are taken, the dose 

delivered in the first year may 

represent only a small portion of the 

total dose delivered over a lifetime. On 

the other hand, if the release consists 

primarily of short-lived radionuclides, 

almost the entire dose may be 

delivered within the first year. 

From the data in Table E-2, it is 

apparent that, for the groups of 

accidents listed, both long and short 

lived radionuclides would be released. 

Consequently, doses due to deposited 

materials from such accidents would be 

relatively high during the first year 

followed by long term exposures at 

lower rates. 

E.1.3 Exposure Pathways 

The principal exposure pathway to 

members of the public occupying land 

contaminated by deposits ofradioactive 

materials from reactor incidents is 

expected to be exposure of the whole 

body to external gamma radiation. 

Although it is normally expected to be 

of only minor importance, the 

inhalation pathway would contribute 

E-3 

additional doses to intemal organs. 

The health risks from other pathways, 

such as beta dose to the skin and direct 

ingestion of dirt, are also expected to 

be minor in comparison to the risks 

due to extemal gamma radiation 

(AR-89). Skin and inhalation dose 

would, however, be important exposure 

pathways for source terms with 

significant fractions of pure beta 

emitters, and inhalation dose would be 

important for source terms with 

significant fractions of alpha emitters. 

Since relocation, in most cases, 

would not be an appropriate action to 

prevent radiation exposure from 

ingestion of food and water, these 

exposure pathways have not been 

included in this analysis. They are· 

addressed in Chapters 3 and 6. In 

some instances, however, . where 

withdrawal of food and/or water from 

use would, in itself, create a • health 

risk, relocation may be an appropriate 

altemative protective action. In this 

case, the committed effective dose 

equivalent from ingestion should be 

added to the projected dose from 

deposited radionuclides via other 

pathways, for decisions on relocation. 

E.1.4 Response Scenario 

This section defines the response 

zones, population groups, and the 

activities assumed for implementation 

of protective actions during the 

intermediate phase. 

After passage of the radioactive 

plume, the results of environmental 

monitoring will become available for 

use in making decisions to protect the 

public. Sheltering, evacuation, and 

other actions taken to protect the 

public from the plume will have 

already been implemented. The tasks 

immediately ahead will be to (1) define 

the extent and characteristics of 

deposited radioactive material and 

identify a restricted zone in accordance 

with the PAG for relocation, (2) 

relocate persons from and control 

access to the restricted zone, (3) allow 

persons to retum to areas outside the 

restricted zone, ( 4) control the spread 

of and exposure to surface 

contamination, and ( 5) apply simple 

decontamination and other low-cost, 

low-risk techniques to reduce the dose 

to persons who are not relocated. 

Because ofthe various source term 

characteristics and the different 

protective actions involved (evacuation, 

sheltering, relocation, decontamination, 

and other actions to reduce doses to "as 

low as reasonably achievable" levels), 

the response areas for different 

protective actions may be complex and 

may vary in size with respect to each 

other. Figure E-1 shows a generic 

example ofsome ofthe principal areas 

involved. The area covered by the 

plume is assumed to be represented by 

area 1. In reality, variations in 

meteorological conditions would almost 

certainly produce a more complicated 

shape. 

Based on plant conditions or other 

considerations prior to or after the 

release, members of the · public are 

assumed to have already been 

evacuated from area 2 and sheltered in 

area 3. Persons who were evacuated or 

E-4 

PLUME TRAVEL ... 

DIRECTION 

ARBITRARY SCALE 

LEGEND 

...-.. I I 1. PLUME DEPOSITION AREA. 

.._.. 

~ 2. AREA FROM WHICH POPULATION IS EVACUATED. 


~ 3. AREA IN WHICH POPULATION IS SHELTERED. 


m4. AREA FROM WHICH POPULATION IS RELOCATED (RESTRICTED ZONE). 


FIGURE E-1. RESPONSE AREAS. 

sheltered as a precautionary action for 

protection from the plume but whose 

homes are outside the plume deposition 

area (area 1) are assumed to return to 

their homes or discontinue sheltering 

when environmental monitoring 

verifies the outer boundary of area 1. 

Area 4 is the restricted zone and is 

defined as the area where projected 

doses are equal to or greater than the 

relocation P AG. The portion of area 1 

outside of area 4 is designated as a 

study zone and is assumed to be 

occupied by the public. However, 

contamination levels may exist here 

that would be of concern for continued 

monitoring and decontamination to 

maintain radiation doses "as low as 

reasonably achievable" (ALARA). 

The relative positions of the 

boundaries shown in Figure E-1 are 

dependent on areas evacuated and 

sheltered. For example, area 4 could 

fall entirely inside area 2 (the area 

evacuated) so that relocation ofpersons 

from additional areas would not be 

required. In this case, the relocation 

PAG would be used only to determine 

areas to which evacuees could return. 

Figure E-2 provides, for 

perspective, a schematic representation 

ofthe response activities expected to be 

in progress in association with 

implementation ofthe PAGs during the 

intermediate phase ofthe response to a 

nuclear incident. 

E.2 Considerations 	 for Establishing 

P AGs for the Intermediate Phase 

The major considerations in 

selecting values for these PAGs for 

relocation and other actions during the 

intermediate phase are the four 

principles that form the ba:sis for 

selecting all P AGs. Those are 

discussed in Section E.2.1. Other 

considerations (Federal radiation 

protection guidance and risks 

commonly confronting the public) are 

discussed in Sections E.2.2 and E.5. 

In addition, a planning group 

consisting of State, Federal, and 

industry officials provided 

recommendations in 1982 which EPA 

considered in the development of the 

format, nature, and applicability of 

P AGs for relocation. Abbreviated 

versions ofthese recommendations are 

as follows: 

a. The PAGs ·should apply to 

commercial, light-water power reactors. 

b. The PAGs should be based 

primarily on health effects. 

c. Consideration should be given to 

establishing a range of PAG values. 

d. The PAGs should be established as 

high as justifiable because at the time 

of the response, it would be possible to 

lower them, ifjustified, but it probably 

would not be possible to increase them. 

e. Only two zones (restricted and 

unrestricted) should be established to 

simplify implementation of the PAGs. 

E-6 

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~ 

PERIOD OF 


RELEASE, 


DISPERSION, 


DEPOSITION, 


SHELTERING, 


EVACUATION, 


AND ACCESS 


CONTROL 


(NO TIME SCALE) 


~ CONDUCT AERIAL AND GROUND SURVEYS. DRAW IS?DOSE RATE LINES. 

~ IDENTIFY HIGH DOSE RATE AREAS. CHARACTERIZE CONTAMINATION. 

·~~ RELOCATE POPULATION FROM HIGH DOSE RATE AREAS.

~ALLOW IMMEDIATE RETURN OF EVACUEES TO NONCONTAMINATED AREAS. 

ESTABLISH RESTRICTED ZONE BOUNDARY AND CONTROLS. 


Q RELOCATE REMAINING POPULATION FROM WITHIN RESTRICTED ZONE. 


w GRADUALLY RETURN EVACUEES UP TO RESTRICTED ZONE BOUNDARY. 1­

D. 

w 

~ -

~CONDUCT D-CON AND SHIELDING EVALUATIONS AND ESTABLISH PROCEDURES

:c FOR REDUCING EXPOSURE OF PERSONS WHO ARE NOT RELOCATED. 0 

0 

z PERFORM DETAILED ENVIRONMENTAL MONITORIHG. 

0 PROJECT DOSE BASED ON DATA. 

i=

u; DECONTAMINATE ESSENTIAL FACILITIES AND THEIR ACCESS ROUTES. 0 

D. RETRIEVE VALUABLE AND ESSENTIAL RECORDS AND POSSESSIONS. w 

Q 

­ REESTABLISH OPERATION OF VITAL SERVICES. 

..BEGIN RECOVERY ACTIVITIES. 

MONITOR AND APPLY 


ALARA IN OCCUPIED 


CONTAMINATED AREAS. 


0.1 1.0 10 100 1,000 

TIME AFTER DEPOSITION (DAYS) 

FIGURE E·2 POTENTIAL TIME FRAME OF 'RESPONSE TO A NUCLEAR INCIDENT. 

f. The PAGs should not include past 

exposures. 

g. Separate PAGs should be used for 

ingestion pathways. 

h. PAGs should apply only to 

exposure during the first year after an 

incident. 

Although these PAGs apply to any 

nuclearincident, primary consideration 

was given to the case of commercial 

U.S. reactors. In general, we have 

found it possible to accommodate most 

of the above recommendations. 

E.2.1 Principles 

In selecting values for these PAGs, 

EPA has been guided by the principles 

that were set forth in Chapter 1. They 

are repeated here for convenience: 

1. Acute effects on health (those that 

would be observable within a short 

period of time and which have a dose 

threshold below which they are not 

likely to occur) should be avoided. 

2. The risk of delayed effects on 

health (primarily cancer and genetic 

effects, for which linear nonthreshold 

relationships to dose are assumed) 

should not exceed upper bounds that 

are judged to be adequately protective 

of public health, under emergency 

conditions, and are reasonably 

achievable. 

3. PAGs should not be higher than 

justified on the basis of optimization of 

cost and the collective risk of effects on 

health. That is, any reduction of risk 

to public health achievable at 

acceptable cost should be carried out. 

4. Regardless ofthe above principles, 

the risk to health from a protective 

action should not itself exceed the risk 

to health from the dose that would be 

avoided. 

Appendix B analyzed the risks of 

health effects as a function of dose 

(Principles 1 and 2). Considerations 

for selection of P AGs for the 

intermediate phase of a nuclear 

incident differ from those for selection 

of PAGs for the early phase primarily 

with regard to implementation factors 

(i.e., Principles 3 and 4). Specifically, 

they differ with regard to cost of 

avoiding dose, the practicability of 

leaving infirm persons and prisoners in 

the restricted zone, and avoiding dose 

to fetuses. Although sheltering is not 

generally a suitable alternative to 

relocation, other alternatives (e.g., 

decontamination and shielding) are 

suitable. These considerations are 

reviewed in the sections that follow. 

E.2.1.1 Cost/Risk Considerations 

The Environmental Protection 

Agency has issued guidelines for 

internal use in performing regulatory 

impact analyses (EP-83). These 

include consideration ofthe appropriate 

range of costs for avoiding a statistical 

death. The values are inferred from 

the additional compensation associated 

with employment carrying a higher 

than normal risk of mortality and are 

expressed as a range of $0.4 to $7 

E-8 

million per statistical death avoided. 

The following discussion compares 

these values to the cost of avoiding 

radiation-induced fatal cancers through 

relocation. 

The basis for estimating the 

societal costs ofrelocation are analyzed 

in a report by Bunger (BU-89). 

Estimated incremental societal costs 

per day per person relocated are shown 

below. (Moving and loss of inventory 

costs are averaged over one year.) 

Moving $1.70 

Loss of use of residence 2.96 

Maintain and secure vacated 

property 0.74 

Extra living costs 1.28 

Lost business and inventories 14.10 

Extra travel costs 4.48 

Idle government facilities 1.29 

Total $26.55 

The quantity ofinterest is the dose 

at which the value of the risk avoided 

is equal to the cost ofrelocation. Since 

the above costs are expressed in 

dollars/person-day, it is convenient to 

calculate the dose that must be avoided 

per-person day. The equation for this 

is: 

c 

VR 

where: 

HE= dose 

C = cost ofrelocation 

V =value of avoiding a 

statistical death 

R = statistical risk of death from 

radiation dose 

Using the values cited above, and 

a value for R of 3x10"4 deaths/rem (See 

Appendix B), one obtains a range of 

doses of about. 0.01 to 0.2 rem/day. 

Thus, over a period of one year the 

total dose that should be avoided to 

justify the cost of relocation would be 

about 5 to 80 rem. 

These doses are based on exposure 

accumulated over a period of one year. 

However, exposure rates decrease with 

time due to radioactive decay and 

weathering. Thus, for any given 

cumulative dose in the first year, the 

daily exposure -rate continually 

decreases, so that a relocated person 

will avoid dose more rapidly in the first 

part ofthe year than later. Figure E-3 

shows the effect of changing exposure 

rate on the relationship between the 

cost of avoiding a statistical death and 

the time after an SST-2 accident (See 

Table E-1) for several assumed 

cumulative annual doses. The curves 

represent the cost per day divided by 

the risk of fatality avoided by 

relocation per day, at time t, for the 

annual dose under consideration, 

where tis the number of days after the 

accident. The right ordinate shows the 

gamma exposure rate (mRih) as a 

function of time for ·the postulated 

radionuclide mix at one meter height. 

The convex downward curvature 

results from the rapid decay of 

short~lived radionuclides during the 

first few weeks following the accident. 

Since the cost per day for relocation is 

assumed to be constant and the dose 

avoided per day decreases, the cost 

effectiveness of relocation decreases 

with time. For this reason it is cost 

E-9 

3 I 

0.5 rem 

...,., 

2 ~ v 	 1 rem 

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0 


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0 

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w 

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a: 	

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0 

2 ( 

5 10 15 20 25 30 

TIME AFTER ACCIDENT {days) 

FIGURE E-3. 	COST OF AVOIDING STATISTICAL FATALITIES AND 

EXPOSURE RATES CORRESPONDING TO VARIOUS 

TOTAL FIRST YEAR DOSES (ASSUMES AN SST-2 

ACCIDENT AND A $27 PER PERSON-DAY COST OF 

RELOCATION). 

w 

(/) 

0 

Cl 

..J 

<C 

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z 

z 

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0 

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z 

0 3 	 z 

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6 	 J::

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8 

9 

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E-10 

effective to quickly recover areas where 

the population has been relocated at 

projected doses only marginally greater 

than the PAG. 

Only trends and general 

relationships can be inferred from 

Figure E-3 because it applies to a 

specific mix ofradionuclides. However, 

for this radionuclide mix, cost analysis 

supports relocation at doses as low as 

one rem for the first week and two rem 

for up to 25 days after an accident. 

E.2.1.2 Protection of Special Groups 

Contrary to the situation for 

evacuation during the early phase ofan 

incident, it is generally not practical to 

leave a few persons behind when most 

members of the general population 

have been relocated from a specified 

area for extended periods of time. 

Further, no data are available on 

differing risks ofrelocation for different 

population groups. In the absence of 

such data, we have assumed that these 

risks will be similar to those from 

evacuation. Those risks were taken as 

equivalent to the health risk from 

doses of 30 mrem for members of the 

general population and of150 mrem for 

persons at high risk from evacuation 

(see Appendix C). Therefore, to satisfy 

Principle 4 for population groups at 

high risk, the PAG for relocation 

should not be lower than 150 millirem. 

Given the arbitrary nature of this 

derivation, it is fortunate that this 

value is much lower than the PAG 

selected, and is therefore not an 

important factor in its choice. 

Fetuses are a special group at 

greater risk of .health effects from 

radiation dose than is the general 

population, but not at significantly 

greater risk from relocation itself. The 

risk of mental retardation from fetal 

exposure (see Appendix B) is 

significant. It is affected by the stage 

of pregnancy relative to the assumed 

one-year exposure, because the 8th to 

15th week critical period during which 

the risk is greatest, must be considered 

in relation to the rapidly changing dose 

rate. Taking these factors into 

account, it can be postulated that the 

risk of mental retardation due to 

exposure of the fetus during the 

intermediate phase will range from one 

to five times the cancer risk of an 

average member of the public, 

depending upon when conception 

occurs relative to the time of the 

incident. The elevated risk of 

radiation-induced cancer from exposure 

of fetuses· is less significant, as 

discussed in Appendix B. 

It will usually be practicable to 

reduce these .risks by .establishing a 

high priority for e~orts other than 

relocation to reduce the dose in cases 

where pregnant women reside near the 

boundary of the restricted zone. 

However, women who are less than 

seven months pregnant may wish to 

relocate for the balance of their 

pregnancy ifthe projected dose during 

pregnancy cannot be reduced below 0.5 

rem. 

E-ll 
E.2.2 Federal Radiation Protection 

Guides 

The choice of a PAG at which 

relocation should be implemented does 

not mean that persons outside the 

boundary ofthe restricted zone should 

not be the subject of other protective 

actions to reduce dose. Such actions 

are justified on the basis of existing 

Federal radiation protection guidance 

(FR-65) for protecting the public, 

including implementation of the 

principle of maintaining doses "as low 

as reasonably achievable" (ALARA). 

The intended actions to protect the 

public from radiation doses on the 

basis of Radiation Protection Guides 

(RPGs) are those related to source 

control. Although it is reasonable for 

members ofthe public to receive higher 

exposure rates prior to the source term 

being brought under control, the 

establishment of acceptable values for 

relocation PAGs must include 

consideration ofthe total dose over the 

average remaining lifetime of exposed 

individuals (usually taken as 50 years). 

The nationally and intemationally 

recommended upper bound for dose in 

a single year from man-made sources, 

excluding medical radiation, is 500 

mrem per year to the whole body of 

individuals in the general population 

(IC-77, FR-65). These recommendations were not developed for nuclear 

incidents. They are also not 

appropriate for chronic exposure. The 

ICRP recommends an upper bound of 

100 mrem per year, from all sources 

combined, for chronic exposure (IC-77). 

The corresponding 50-year dose at 100 

mrem/yr is 5 rem. We have chosen to 

limit: a) the projected first year dose to 

individuals from an incident to the 

Relocation PAG, b) the projected second 

year dose to 500 :mrem, and c) the dose 

projected over a fifty-year period to 5 

rem. Due to the extended duration of 

exposures and the short half-life of 

important radioiodines, no special 

limits for thyroid dose are needed. 

E.3. Dose from Reactor Incidents 

Doses from an environmental 

source will be reduced through the 

natural processes of weathering and 

radioactive decay, and from the 

shielding associated with part time 

occupancy in homes and other structures. Results of dose calculations 

based on the radiological characteristics of releases from three categories 

of postulated, fuel-melt, reactor 

accidents (SST-1, SST-2, and SST-3) 

(SN-82) and a weathering model from 

WASH-1400 (NR-75) are shown in 

Table E-3. This table shows the 

relationship between annual doses for 

the case where the sum, over fifty 

years, of the effective dose equivalent 

from gamma radiation and the 

committed effective dose equivalent 

from inhalation of resuspended 

materials is 5 rem. Radioactive decay 

and weathering reduces the second 

year dose from reactor incidents to 20 

to 40 percent of the first year dose, 

depending on the radionuclide mix in 

the release. 

Based on studies reported in 

WASH-1400 (NR-75), the most 

conservative dose reduction factor for 

E-12 

Table E-3 Annual Doses Corresponding to 5 Rem in 50 Yearsa 

Dose According to Accident CategorY> (rem) 


Year 


SST-1 SST-2 SST-3 


1 1.25 1.60 1.91 

2 0.52 0.44 0.38 


3 ·0.33 0.28 0.24 


4 0.24 0.20 0.17 

5 0.18 0.16 0.13 

6 0.14 0.12 0.11 

7 0.12 0.11 0.090 

8 0.10 0.085 0.070 

9 0.085 0.075 0.065 

10 0.080 0.070 0.060 

11 0.070 0.060 0.050 

12 0.060 0.055 0.050 

15 0.055 0.045 0.040 

20 0.045 0.040 0.030 

25 0.040 0.035 0.025 

30 0.030 0.030 0.025 

40 0.025 0.020 0.020 

50 0.020 0.015 0.010 

aWhole body dose equivalent from gamma radiation plus committed effective dose equivalent from 

inhalation assuming a resuspension factor of 10"6 m·1

• Weathering according to the WASH-1400 

model (NR-75) and radioactive decay are assumed. 

bRadionuclide abundance ratios are based on reactor inventories from WASH-1400 (NR-75). 

Release quantities for accident categories SST-1, SST-2 and SST-3 are shown in Table E-2. Initial 

concentrations are assumed to have decayed for 4 days after reactor shutdown. 

structures (frame structures) is about relocated to 60 percent (or less) of the 

0.4 (dose inside divided by dose values shown in Table E-3 before the 

outside) and the average fraction of application of decontamination. 

time spent in a home is about 0.7. 

Combining these factors yields a net 

dose reduction factor of about 0.6. In E.4. Alternatives to Relocation 

most cases, therefore, structural 

shielding would be expected to reduce Persons who are not relocated, in 

the dose to persons who are not addition to dose reduction provided by 

E-13 

partial occupancy in homes and other 

structures, can reduce their dose by the 

application ofvarious techniques. Dose 

reduction efforts can range from the 

simple processes of scrubbing and/or 

flushing surfaces, soaking or plowing of 

soil, removal and disposal of small 

spots of soil found to be highly 

contaminated (e.g., froin settlement of 

water), and spending more time than 

usual in lower exposure rate areas 

(e.g., indoors), to the difficult and time 

consuming processes of removal, 

disposal, and replacement of 

contaminated surfaces. It is 

anticipated that simple processes 

would be most appropriate to reduce 

exposure rates for persons living in 

contaminated areas outside the 

restricted zone. Many of these can be 

carried out by the residents with 

support from officials for monitoring, 

guidance on appropriate actions, and 

disposal. The more difficult processes 

will usually be appropriate for recovery 

of areas from which the population is 

relocated. 

Decontamination experiments 

involving radioactive fallout from 

nuclear weapons tests have shown 

reduction factors for simple 

decontamination methods in the 

vicinity of 0.1 (i.e., exposure rate 

reduced to 10 percent of original 

values). However, recent experiments 

at the Riso National Laboratory in 

Denmark (WA-82, WA-84), using 

firehoses to flush asphalt and concrete 

surfaces contaminated with radioactive 

material of the type that might be 

deposited from reactor accidents, show 

decontamination factors for 

radionuclides chemically similar to 

cesium that are in the range of 0.5 to 

0.95, depending on the delay time after 

deposition before flushing is applied. 

The factor for ruthenium on asphalt 

was about 0.7 and was independent of 

the delay of flushing. The results of 

these experiments indicate · that 

decontamination of the important 

reactor fission products from asphalt or 

concrete surfaces may be much more 

difficult than decontamination of 

nuclear weapons fallout. Other simple 

dose reduction methods listed above 

would be effective to varying degrees. 

The average dose reduction factor for 

gamma radiation from combinations of 

simple decontamination methods is 

estimated to be at least 0.7. 

Combining this with the 40 percent 

reduction estimated above for 

structural shielding indicates that the 

doses listed in Table E-3 may be more 

than twice as high as those which 

would actually be received by persons 

who are not relocated. 

E.5 Risk Comparisons 

Many hazardous conditions and 

their associated risks are routinely 

faced by the public. A lingering 

radiation dose will add to those risks, 

as opposed to substituting one risk for 

another, and, therefore, radiation 

protection criteria cannot be justified 

on the basis of the existence of other 

risks. It is, however, useful to review 

those risks to provide perspective. This 

section compares the risks associated 

with radiation doses to those associated 

with several other risks to which the 

public is commonly exposed. 

E-14 

Figure E-4 compares recent 

statistics for the average lifetime risk 

of accidental death in various 

occupations to the estimated lifetime 

risk offatal cancer for members of the 

general population exposed to radiation 

doses ranging up to 25 rem. 

Non-radiation risk values are derived 

from information in reference (EP-81) 

and radiation risk values are from 

Appendix B. These comparisons show, 

for example, that the lifetime cancer 

risk associated with a dose of 5 rem is 

comparable to the lifetime risk of 

accidental death in some of the safest 

occupations, and is well below the 

average lifetime risk of accidental 

death for all industry. 

Risks of health effects associated 

with radiation dose can also be 

compared to other risks facing 

individuals in the general population. 

The risks listed in Table E-4 are 

expressed as the number of premature 

deaths and the average reduction of 

life-span due to these deaths within a 

group of 100,000 persons. For 

purposes of comparison, a dose of 5 

rem to each member of a population 

group of 100,000 persons 

representative of the average U.S. 

population carries an estimated 

lifetime risk of about 150 fatal cancers 

(see Appendix B). The number of 

deaths resulting from the various 

causes listed in Table E-4 is based on 

data from mortality records. 

In summary, the risk·ofpremature 

death normally confronting the public 

from specific types of accidents ranges 

from about 2 to 1000 per 100,000 

population. The estimated radiation 

doses required to produce a similarrisk 

of death from radiation-induced cancer 

range from about 0.07 to 33 rem. 

E.6 Relocation PAG Recommendations 

Previous sections have reviewed 

data, standards, and other information 

relevant to establishing P AGs for 

relocation. The results are 

summarized in Table E-5, in relation to 

the principles setforth in Section E.2.1. 

Based on the avoidance of acute 

effects alone (Principle 1) 50 rem and 

10 rem are upper bounds on the dose 

at which relocation of the general 

population and fetuses, respectively, is 

justified. However, on the basis of 

control of chronic risks (Principle 2) a 

lower upper bound is appropriate. Five 

rem is taken as an upper bound on 

acceptable risk for controllable lifetime 

exposure to radiation, including 

avoidable exposure to accidentally 

deposited radioactive materials. This 

corresponds to an average of 100 mrem 

per year for fifty years, a value 

commonly accepted as an upper bound 

for chronic annual exposure of 

members ofthe public from all sources 

of exposure combined, other than 

natural background and medical 

radiation (IC-77). In the case of 

projected doses from nuclear reactor 

accidents, a five rem lifetime dose 

corresponds to about 1.25 to 2 rem 

from exposure during the first year and 

0.4 to 0.5 rem from exposure during 

the second year. 

Analyses based on Principle 3 

(cost/risk) indicate that considering cost 

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w 

~ 

1---CONSTRUCTION & MINING 

1---AGRICULTURE 

I--TRANSPORTATION & PUBLIC UTILITIES 

25 rem 

AVERAGE FOR All UTILITIES 

I--GOVERNMENT 

t---SERVICE 

1--- MANUFACTURING 

t--- RETAIL & 

WHOLESALE 


TRADE 


1--1._1 rem 

0.5 rem 

2 4 6 	 8 10 12 14 16 18 20 22 24 26 

rem (effective dose equivalent) 

FIGURE E·4. 	 AVERAGE LIFETIME RISK OF DEATH FROM WHOLE BODY RADIATION DOSE 

COMPARED TO THE AVERAGE RISK OF ACCIDENTAL DEATH FROM LIFETIME 

(47 YEARS) OCCUPATION IN VARIOUS INDUSTRIES. 

E-16 

Table E-4 Measure of Lifetime Risk of Mortality from a Variety of Causesa . 

(Cohort Size =100,000) 

Nature of 

accident 

Falls 

Fires 

Drowning 

Poisoning 

by drugs and 

medicaments 

Cataclysmb 

Bites and 

stingsc 

Electric 

current 

in homesd 

Premature 

deaths 

1,000 

300 

190 

69 

17 

8 

8 

Aggregate years 


of life lost 


to cohort 


12,000 

7,600 

8,700 

2,500 

490 

220 

290 

Reduction of 

life expectancy 

at birth (years) 

0.12 

0.076 

0.087 

0.025 

0.005 

0.002 

0.003 

Average years 


of life lost to 


premature deaths 


11 

26 

45 

37 

30 

27 

37 

"All mortality effects shown are calculated as changes from the U.S. Life Tables for 1970 to life 

'tables with the cause of death under investigation removed. These effects also can be interpreted 

as changes in the opposite direction, from life tables with the cause of death removed to the 1970 

Life Table. Therefore, the premature deaths and years of life lost are those that would be 

experienced in changing from an environment where the indicated cause of death is not present to 

one where it is present. All values are rounded to no more than two significant figures. 

bCataclysm is defined to include cloudburst, cyclone, earthquake, flood, hurricane, tidal waves, 


tornado, torrential rain, and volcanic eruption. 


"Accidents by bite and sting of venomous animals and insects include bites by centipedes, 

venomous sea animals, snakes, and spiders; stings of bees, insects, scorpions, and wasps; and other 

venomous bites and stings. Other accidents caused by animals include bites by any animal and 

nonvenomous insect; fallen on by horse or other animal; gored; kicked or stepped on by animal; ant 

bites; and run over by horse or other animal. It excludes transport accidents involving ridden 

animals; and tripping,_ falling over an animal Rabies is also·excluded. 

dAccidents caused by electric current from home wiring and appliances include bum by electric 


current, electric shock or electrocution from exposed wires, faulty appliances, high voltage cable, 


live rail, and open socket. It excludes bum by heat from electrical appliances and lighting. 


E-17 

Table E-5 Summary of Considerations for Selecting PAGs for Relocation 

Dose Consideration Principle 

(rem) 

50 	 Assumed threshold for acute health effects in adults. 1 


10 	 Assumed threshold for acute health effects in the fetus. 1 


6 	 Maximum projected dose in first year to meet 0.5 rem in the second 


ye~. 2 


5 	 Maximum acceptable annual dose for normal occupational exposure 


of adults. 2 


5 	 Minimum dose that must be avoided by one year relocation based 


on cost. s 


3 	 Minimum projected first-year dose corresponding to 5 rem 


in 50 years •

11 2 


3 	 Minimum projected first-year dose corresponding to 0.5 rem in the 


secondye~. 2 


2 	 Maximum dose in first year corresponding to 5 rem in 50 years from a 


reactor incident, based on radioactive decay and weathering only. 2 


1.25 	 Minimum dose in fl.rst year corresponding to 5 rem in 50 years from a 


reactor incident based on radioactive decay and weathering only. 2 


0.5 	 Maximum acceptable single-year dose to the general population from 


all sources from non-recurring, non-incident exposure. 2 


0.5 	 Maximum acceptable dose to the fetus from occupational exposure 


of the mother. 2 


0.1 	 Maximum acceptable annual dose to the general population from all 


sources due to routine (chronic), non-incident, exposure. 2 


0.03 	 Dose that carries a risk assumed to be equal to or less than that 


from relocation. 4 


"Assumes the source term is from a reactor incident and that simple dose reduction methods are 

applied during the first month after the incident to reduce the dose to persons not relocated from 

contaminated areas. 

E-18 

alone would not drive the P AG to 

values less than 5 rem. Analyses in 

support of Principle 4 (risk of the 

protective action itself) provide a lower 

bound for relocation PAGs of 0.15 rem. 

Based on the above, 2 rem 

projected committed effective dose 

equivalent from exposure in the first 

year is selected as the P AG for 

relocation. Implementation of 

relocation at this value will provide 

reasonable assurance that, for a reactor 

accident, a person relocated from the 

outer margin of the relocation zone 

will, by such action, avoid an exposure 

rate which, if continued over a period 

of one year, would result in a dose of 

about 1.2 rem. This assumes that 0.8 

rem would be avoided without 

relocation through normal partial 

occupancy of homes and other 

structures. This PAG will provide 

reasonable assurance that persons 

outside the relocation zone, following a 

reactor accident, will not exceed 1.2 

rem in the "first year, 0.5 rem in the 

second year, and 5 rem in 50 years. 

The implementation of simple dose 

reduction techniques, as discussed in 

section E-4, will further reduce dose to 

persons who are not relocated from 

contaminated areas. Table E-6 

summarizes the estimated maximum 

dose that would be received by these 

persons for various reactor accident 

categories with and without the 

application of simple dose reduction 

techniques. In the case of non-reactor 

accidents these doses will, in general, 

differ, and it may be necessary to apply 

more restrictive P AGs to the first year 

in order to assure conformance to ·the 

second year and lifetime objectives 

noted above. 

Since effective dose does not 

include dose to theskin (and for other 

reasons discussed in Appendix B) 

protective action to limit dose to skin is 

recommended at a skin dose 50 times 

the numerical value of the PAG for 

effective dose. This includes 

consideration of the risk of both 

curable and fatal cancers. 

E.7 Criteria for Reentry into the 

Restricted Zone 

Persons may need to reenter the 

restricted zone for a variety ofreasons, 

including radiation monitoring, 

_recovery work, animal care, property 

maintenance, and factory or utility 

operation. Some persons outside the 

restricted zone, by nature of their 

employment or habits, may also receive 

higher than average radiation doses. 

Tasks that could cause such exposures 

include: 1) chahging of filters on air 

handling equipment (including 

vehicles), 2) handling and disposal of 

contaminated vegetation (e.g., grass 

and leaves) and, 3) operation of control 

points for the restricted zone. 

Individuals who reenter the 

restricted zone or who perform tasks 

involving exposure rates that would 

cause their radiation dose to exceed 

that permitted by the P AGs should do 

so in accordance with existing Federal 

radiation protection guidance for 

occupationally exposed workers 

(EP-87). The basis for that guidance 

has been provided elsewhere (EP-87). 

E-19 

Table E-6 	 Estimated Maximum Doses to Nonrelocated Persons From Areas 

Where the Projected Dose is 2 RE~ 

Dose (rem) 

Accident No additional dose reduction Early simple dose reductionb 

Category Year 1 Year2 50 years Year 1 Year2 50 years 

SST-1 1.2 0.5 5.0 0.9 0.35 3.5 

SST-2 1.2 0.34 3.9 0.9 0.24 2.7 

SST-3 1.2 0.20 3.3 0.9 0.14 2.3 

•Based on relocation at a projected dose of 2 rem in the first year and 40 percent dose reduction to 

nonrelocated persons from normal, partial occupancy in structures. No dose reduction is assumed 

from decontamination, shielding, or special limitations on time spent in high exposure rate areas. 

~e projected dose is assumed to be reduced 30 percent by the application of simple dose 

reduction techniques during the first month. Ifthese techniques are completed later in the first 

year, the first year dose will be greater. 

References 

AR-89 Aaberg, Rosanne. Evaluation of Skin 

and Ingestion Exposure Pathways. EPA 

520/1-89-016, U.S. Environmental Protection 

Agency, Washington (1989). 

BU-89 Bunger, Byron M. Economic Criteria 

for Relocation. EPA 520/1-89-015, U.S. 

Environmental Protection Agency, 

Washington (1989) 

EP-81 U.S. Environmental Protection 

Agency. Background Report. Proposed Federal 

Radiation Protection Guidance for 

Occupational Exposure. EPA 520/4-81-003, 

U.S. Environmental Protection Agency, 

Washington (1981). 

EP-83 U.S. Environmental Protection 

Agency. Guidelines for Performing Regulatory 

Impact Analysis. EPA-23-01-84-003, U.S. 

Environmental Protection Agency, 

Washington (1983). 

EP-87 U.S. Environmental Protection 

Agency. Radiation Protection Guidance to 

Federal Agencies for Occupational Exposure. 

Federal Register,.@, 2822; January27, 1987. 

FR-65 Federal Radiation Council Radiation 

Protection Guidance for Federal Agencies. 

Federal Register, 30, 6953-6955; May 22, 1965. 

IA-85 International Atomic Energy Agency. 

Principles for Establishing Intervention 

Levels for Protection of the Public in the 

Event of a Nuclear Accident or Radiological 

Emergency. Safety Series No.72, International 

Atomic Energy Agency, Vienna (1985). 

IC-77 International Commission on 

Radiological Protection. Radiological 

E-20 

Protection. ICRP Publication 26, Pergamon 

Press, Oxford (1977). 

IC-84 International Commission on 

Radiological Protection. Protection of the 

Public in the Event of Major Radiation 

Accidents: Principles for Planning, ICRP 

Publication 40, Pergamon Press, New York 

(1984). . 

' . . . 

NR-75 U.S. Nuclear Regulatory Commission. 

Calculations of Reactor Accident 

Consequences. WASH-1400, U.S. Nuclear 

Regulatory Commission, Washington (1975). 

SN-82 Sandia National Laboratories. 

Technical Guidance for Siting Criteria 

Development. NUREG/CR-2239, U.S. Nuclear 

Regulatory Commission, Washington (1982). 

WA-82 Warming, L. Weathering and 

Decontamination of Radioactivity Deposited 

on Asphalt Surfaces. Riso-M-2273, Riso 

National Laboratory, DK 4000 Roskilde, 

Denmark, (1982). 

WA-84 Warming, L. Weathering and 

Decontamination of Radioactivity Deposited 

on on Concrete Surfaces. RISO-M-2473, Riso 

National Laboratory, DK-4000 Roskilde, 

Denmark. December (1984). 

E-21 


APPENDIXF 

Radiation Protection Criteria 


for the Late Phase 


Background Information 


(Reserved) 


"'(:( U.S. GOVERNMENT PRINTING OFFICE: 1tt2117-G03187003