Defense Threat Reduction Agency

8725 John J. Kingman Road, MS-6201

Fort Belvoir, VA 22060-6201

DISTRIBUTION A. Approved for public release; distribution is unlimited.

February 2022

 

Expedited Processing of Radiation Dose 

Assessments for Military Personnel

of the Enewetak Atoll Cleanup Project 

(1977–1980)

 

 

 

Prepared by:

Leidos, Inc.

For:

Defense Threat Reduction Agency

DTRA-TR-21-050

TECHNICAL REPORT
ii

REPORT DOCUMENTATION PAGE

PLEASE DO NOT RETURN YOUR FORM TO THE ABOVE ORGANIZATION.

1. REPORT DATE

01-02-2022 

2. REPORT TYPE

Technical Report

3. DATES COVERED

START DATE END DATE

4. TITLE AND SUBTITLE

Expedited Processing of Radiation Dose Assessments for Military Personnel of the Enewetak Atoll Cleanup Project (1977–1980)

5a. CONTRACT NUMBER

HDTRA1-15-C-0002 

5b. GRANT NUMBER 5c. PROGRAM ELEMENT NUMBER

5d. PROJECT NUMBER 5e. TASK NUMBER 5f. WORK UNIT NUMBER

6. AUTHOR(S)

McKenzie-Carter, Michael A.; Chehata, Mondher; Fong, Show-Hwa; Schaeffer, Dennis M.

7. PERFORMING ORGANIZATION NAME(S) AND ADDRESS(ES)

Leidos Inc.

11951 Freedom Dr

Reston, VA 20190

8. PERFORMING ORGANIZATION 

REPORT NUMBER

9. SPONSORING/MONITORING AGENCY NAME(S) AND ADDRESS(ES)

Nuclear Technologies Department, Attn: Dr. Paul Blake

Defense Threat Reduction Agency

8725 John J. Kingman Road, Mail Stop 6201

Fort Belvoir, VA 22060-6201

10. SPONSOR/MONITOR'S 

ACRONYM(S)

DTRA RD-NTS

11. SPONSOR/MONITOR'S 

REPORT NUMBER(S)

DTRA-TR-21-050 

12. DISTRIBUTION/AVAILABILITY STATEMENT

DISTRIBUTION A. Approved for public release; distribution is unlimited.

13. SUPPLEMENTARY NOTES

14. ABSTRACT

This report serves as the technical basis document for performing expedited processing of radiation dose assessments (RDAs)

for veterans who participated in the Enewetak Atoll Cleanup Project (ECUP) from 1977 to 1980. Approximately 6,000

Military Service members of the United States Department of Defense participated in the cleanup project. Expedited

processing would result in the assignment of upper-bound, group-based radiation doses to ECUP veterans without the need for

performing individualized RDAs. To create an expedited processing system for ECUP, Expedited Processing Groups (EPGs)

are identified, and maximized upper-bound doses are estimated for each group. Eighty-five percent of the estimated EPG

organ, skin, and lens of the eye doses meet the suitability criteria for dose assignment by expedited processing. Cases that do

not satisfy the criteria for expedited processing are submitted for additional review by an RDA analyst.

15. SUBJECT TERMS

Enewetak Atoll, Environmental Cleanup, Radiation Dose Assessment, Expedited Processing, Veterans Affairs

16. SECURITY CLASSIFICATION OF: 17. LIMITATION OF ABSTRACT

U 

18. NUMBER OF PAGES

a. REPORT 59

U

b. ABSTRACT

U

C. THIS PAGE

U

19a. NAME OF RESPONSIBLE PERSON

Paul K. Blake, PhD

19b. PHONE NUMBER (Include area code)

(571) 616-6117
iii

UNIT CONVERSION TABLE

U.S. customary units to and from international units of measurement*

U.S. Customary Units Multiply by International Units

Divide by†

Length/Area/Volume

inch (in) 2.54 × 10–2 meter (m)

foot (ft) 3.048 × 10–1 meter (m)

yard (yd) 9.144 × 10–1 meter (m)

mile (mi, international) 1.609 344 × 103 meter (m)

mile (nmi, nautical, U.S.) 1.852 × 103 meter (m)

barn (b) 1 × 10–28 square meter (m2)

gallon (gal, U.S. liquid) 3.785 412 × 10–3 cubic meter (m3)

cubic foot (ft3) 2.831 685 × 10–2 cubic meter (m3)

Mass/Density

pound (lb) 4.535 924 × 10–1 kilogram (kg)

unified atomic mass unit (amu) 1.660 539 × 10–27 kilogram (kg)

pound-mass per cubic foot (lb ft–3) 1.601 846 × 101 kilogram per cubic meter (kg m–3)

pound-force (lbf avoirdupois) 4.448 222 newton (N)

Energy/Work/Power

electron volt (eV) 1.602 177 × 10–19 joule (J)

erg 1 × 10–7 joule (J)

kiloton (kt) (TNT equivalent) 4.184 × 1012 joule (J)

British thermal unit (Btu) 

(thermochemical) 1.054 350 × 103 joule (J)

foot-pound-force (ft lbf) 1.355 818 joule (J)

calorie (cal) (thermochemical) 4.184 joule (J)

Pressure

atmosphere (atm) 1.013 250 × 105 pascal (Pa)

pound force per square inch (psi) 6.984 757 × 103 pascal (Pa)

Temperature

degree Fahrenheit (oF) [T(oF) − 32]/1.8 degree Celsius (oC)

degree Fahrenheit (oF) [T(oF) + 459.67]/1.8 kelvin (K)

Radiation

curie (Ci) [activity of 

radionuclides] 3.7 × 1010 per second (s–1

) [becquerel (Bq)]

roentgen (R) [air exposure] 2.579 760 × 10–4 coulomb per kilogram (C kg–1)

rad [absorbed dose] 1 × 10–2 joule per kilogram (J kg–1) [gray (Gy)]

rem [equivalent and effective 

dose] 1 × 10–2 joule per kilogram (J kg–1

) [sievert (Sv)]

*

Specific details regarding the implementation of SI units may be viewed at http://www.bipm.org/en/si/. 

†

Multiply the U.S. customary unit by the factor to get the international unit. Divide the international unit by the factor to get the 

U.S. customary unit.
iv

Table of Contents

Table of Contents...................................................................................................................... iv

List of Figures........................................................................................................................... vi

List of Tables............................................................................................................................ vi

Executive Summary ................................................................................................................. vii

1. Introduction.............................................................................................................................1

1.1 Background..........................................................................................................1

1.2 Purpose of ECUP Expedited Processing...............................................................2

1.3 Scope of ECUP Expedited Processing..................................................................2

1.4 Rationale for Developing an Expedited Processing Approach for ECUP RDAs....3

2. Methodology for the Development of an Expedited Processing Approach for ECUP 

Participants.............................................................................................................................4

2.1 Expedited Processing Concept .............................................................................4

2.2 Confidence in Assigned EPG Doses.....................................................................5

2.3 Suitability of EPG Doses......................................................................................5

2.3.1. Internal Organ and Skin Doses .................................................................5

2.3.2. Lens of the Eye Doses..............................................................................6

2.4 Criteria for Selecting ECUP Expedited Processing Groups...................................6

2.5 Experience Performing ECUP Radiation Dose Assessments ................................7

2.6 Exclusion from Expedited Processing ..................................................................8

2.6.1. Exclusion Based on Exceedance of Limiting Doses..................................8

2.6.2. Exclusion Based on Unusual Participation or Exposure Scenario............11

3. Identification and Selection of Expedited Processing Groups ................................................12

3.1 Participant Population and General Radiation Exposure Scenarios.....................12

3.1.1. Potentially Exposed Population ..............................................................12

3.1.2. Radiation Sources and Exposure Pathways.............................................13

3.2 Expedited Processing Groups and Applicable Exposure Scenarios.....................13

3.2.1. Soil Removal Workers EPG ...................................................................14

3.2.2. Northern Island Workers EPG................................................................14

3.2.3. Lojwa Island Support Workers EPG.......................................................17

3.2.4. Southern Island Workers EPG................................................................17

3.3 Potential Exclusion from Expedited Processing Consideration ...........................18
v

4. Maximizing Exposure Scenarios and Dose Parameter Assumptions ......................................19

4.1 Exposure Scenarios............................................................................................19

4.1.1. Soil Removal Workers EPG ...................................................................19

4.1.2. Northern Island Workers EPG................................................................20

4.1.3. Lojwa Support Workers EPG .................................................................22

4.1.4. Southern Island Workers EPG................................................................23

4.2 External Dose Parameter Values........................................................................24

4.2.1. External Dose Parameter Values Common to all ECUP EPGs................24

4.2.2. External Dose Parameter Values Specific to each EPG...........................25

4.3 Internal Dose Parameter Values .........................................................................27

4.3.1. Internal Dose Parameter Values Common to all ECUP EPGs.................27

4.3.2. Internal Dose Parameter Values Specific to each EPG............................30

4.4 Skin Dose Parameter Values..............................................................................32

4.4.1. Parameter Values for Non-contact Skin Doses........................................33

4.4.2. Parameter Values for Dermal Contamination Skin Doses........................34

4.5 Lens of Eye Dose Parameter Values...................................................................36

4.5.1. Parameter Values for Non-contact Lens of Eye Dose..............................36

4.5.2. Parameter Values for Lens of the Eye Dose from Dermal Contamination 

of Eyelid.................................................................................................37

5. Results and Discussion of the ECUP Expedited Processing Doses.........................................38

5.1 Dose Assessment Results...................................................................................38

5.1.1. External and Internal Organ Doses .........................................................38

5.1.2. Skin Doses .............................................................................................38

5.1.3. Lens of the Eye Dose..............................................................................41

5.2 Organ and Skin Site Exclusions from Expedited Processing...............................41

6. References.............................................................................................................................45

Appendix A. Inhalation and Ingestion Dose Coefficients...........................................................47

Abbreviations, Acronyms, and Symbols....................................................................................50
vi

List of Figures

Figure 1. Islands of Enewetak Atoll (Adapted from DNA (1981))............................................15

List of Tables

Table 1. Limiting doses for cancers based on all alpha or all photon radiation ..........................10

Table 2. Limiting doses for skin cancers assuming all alpha or all photon radiation..................11

Table 3. Military Service element and DNA/JTG staffing of the Enewetak Cleanup Project.....12

Table 4. Enewetak Atoll islands...............................................................................................16

Table 5. External dose parameter values common to all ECUP EPGs.......................................25

Table 6. External exposure rates for ECUP EPGs.....................................................................26

Table 7. Internal dose parameter values common to all ECUP EPGs........................................28

Table 8. EPG-specific inhalation dose parameter values...........................................................31

Table 9. Skin site-specific parameter values.............................................................................34

Table 10. Dermal contamination skin dose coefficients............................................................35

Table 11. Parameter values used to estimate the non-contact lens of the eye dose.....................36

Table 12. Parameter values used to estimate the lens of the eye dose from dermal contamination 

of the eyelid..............................................................................................................37

Table 13. Estimated organ doses for ECUP EPGs (rem) * .........................................................39

Table 14. Upper-bound external lens of the eye and skin doses for ECUP EPGs.......................40

Table 15. EPG and organ combinations not recommended for expedited processing ................42

Table 16. Recommendations for EPG dose assignments for skin cancer cases for “American 

Indian or Alaska Native”, “Asian, Native Hawaiian, or other Pacific Islander”, and 

“Black” participants..................................................................................................43

Table 17. Recommendations for EPG dose assignments for skin cancer cases for “White 

(Hispanic)” and “White (Non-Hispanic)” participants...............................................44

Table A-1. ICRP 68 Organ Inhalation Dose Coefficients (rem pCi−1) * .....................................48

Table A-2. ICRP 68 Organ Ingestion Dose Coefficients (rem pCi−1) * ......................................49
vii

Executive Summary

Expedited processing of radiation dose assessments (RDAs) by the Nuclear Test 

Personnel Review (NTPR) program is an option used by the Defense Threat Reduction Agency 

(DTRA) to assign doses in response to requests for dose information from the Department of 

Veterans Affairs (VA). The procedure was recommended by the Veterans’ Advisory Board on 

Dose Reconstruction (VBDR) to allow for the timely processing of a veteran’s claim while 

ensuring that the assigned doses are greater than the doses the veteran actually accrued during 

the performance of their duties. Procedures for expedited processing of claims for veterans 

potentially exposed during atmospheric nuclear tests have been used by DTRA since 2007.

Expedited processing procedures were expanded in 2015 to include veterans who were World 

War II Prisoners of War (POW) in Japan and those veterans who participated in post-war 

occupation forces near Hiroshima and Nagasaki, Japan. 

This technical report was prepared to further extend NTPR’s expedited processing 

methodology to include veterans who participated in the Enewetak Atoll Cleanup Project 

(ECUP). The ECUP was conducted from 1977 to 1980 and involved the cleanup of radiological 

contamination remaining on Enewetak Atoll following the end of U.S. atmospheric nuclear 

testing. This report documents the technical basis for the estimation of radiation doses suitable 

for assignment using expedited processing of ECUP veteran RDAs by DTRA. Following 

approval and publication of this report, the implementation of expedited processing of ECUP 

RDAs will be documented in a DTRA standard operating procedure.

As in current DTRA expedited processing implementations, expedited processing of 

ECUP veteran RDAs involves the identification of coherent Expedited Processing Groups 

(EPGs) to include most of the approximately 6,000 Department of Defense (DoD) ECUP 

participants. To accomplish this requirement, four proposed EPGs were identified for individuals 

who share common aspects of radiation exposure scenarios and who can be grouped for purposes 

of upper-bound radiation dose assignments. The four ECUP EPGs are as follows:

• Soil Removal Workers: personnel who handled soil removed from one of the five northern 

islands that were identified for cleanup of transuranic (TRU) contamination by soil removal

• Northern Island Workers: personnel who worked on northern islands of the atoll other than 

the five soil-removal islands and were not support personnel who worked exclusively on 

Lojwa Island

• Lojwa Island Support Workers: personnel whose duties were on Lojwa Island and provided 

support services to the cleanup operations on the northern islands

• Southern Island Workers: personnel whose duties were primarily limited to the southern 

islands of the atoll. 

Radiation dose estimates for the ECUP EPGs were developed in a manner similar to that 

used for EPGs previously developed by the NTPR program. The organ and skin doses estimated

for each ECUP EPG and the bounding dose to the lens of the eye are based on high-sided and 
viii

maximizing parameter values and assumptions. These assumptions are designed to produce EPG 

doses that are higher than any upper-bound doses calculated in an individualized full RDA by 

detailed dose assessment for any member of the respective EPG. Consequently, the EPG doses 

estimated in this report are suitable for assignment in the expedited processing of RDAs for 

ECUP participants who can be included in one of the proposed EPGs, except in excluded cases 

as specified below.

To be suitable for assignment to a veteran, the EPG total organ, skin, or lens of the eye

dose must not only bound a veteran’s actual total dose but also must be well below the dose that 

would result in a service-connection determination. To assess whether EPG doses are well below 

this level, limiting doses (LDs) were estimated for all organ cancers/diseases and three skin 

cancer types. The LD value is the radiation dose that results in a probability of causation of 

40 percent for an organ, tissue, or skin cancer. It was determined that the majority of the 

recommended ECUP EPG doses estimated for 24 internal organs and 17 skin sites for each EPG 

are less than the applicable LD and are therefore suitable for assignment by expedited 

processing. 

For cases where the EPG total organ dose is higher than the applicable LD, expedited 

processing is not initially recommended and veteran doses should be estimated by alternate 

methods that may include a detailed RDA analysis. Such exceptions include EPG total organ 

doses for two out of 96 (about 2 percent) EPG/organ combinations and EPG total skin doses for 

74 out of 408 (less than 20 percent) EPG/cancer/race category/skin site combinations that exceed 

their respective LDs. Veteran cases involving these combinations should be subjected to further 

detailed evaluation to determine suitability of expedited processing. The estimated upper-bound 

dose to the lens of the eye applicable to all EPGs is much lower than the minimum dose judged 

to induce posterior subcapsular cataracts and is therefore suitable for assignment in all ECUP 

EPG cases. Finally, claims involving cancers or diseases that do not have associated limiting 

doses identified in this report are not recommended for expedited processing unless appropriate 

surrogate organs and limiting doses are identified.

Additionally, exclusions from using expedited processing may be necessary when a 

veteran’s scenario of participation and radiation exposure cannot be categorized to fit any of the 

characteristics described for the four ECUP EPGs. Unusual participation and exposure scenarios 

may involve sources of radiation or pathways that are not accounted for within dose components 

of one of the four ECUP EPGs. Unusual situations may involve veterans remaining aboard ships 

anchored in the lagoon or individuals who participated in the removal and disposal of a small 

number of bags containing plutonium fragments. Other examples are personnel who had 

radiological lab duties or contaminated laundry duties. All excluded cases require a more 

detailed case review and dose assessment. 
1

1.

Introduction

This report serves as the technical basis document for use by the Defense Threat 

Reduction Agency (DTRA) in performing expedited processing of radiation dose assessments 

(RDAs) for veterans who participated in the Enewetak Atoll Cleanup Project (ECUP) from 1977 

to 1980. Approximately 6,000 military service members of the United States Department of 

Defense (DoD) participated in the cleanup project. The DoD established a Joint Task Group 

(JTG) within the Defense Nuclear Agency (DNA) to conduct the cleanup project as authorized 

by Congress in Public Law 95-134 (Congress, 1977). 

Enewetak Atoll was one of the primary locations in the Pacific Ocean where the United 

States conducted atmospheric tests of nuclear devices from the mid-1940s to 1962 (DNA, 1981). 

Radioactive contamination from atmospheric nuclear testing remained at Enewetak Atoll after 

testing ended. During the early 1970s, original inhabitants of the atoll, who had been relocated 

prior to the start of testing, expressed interest in returning to their homeland as they were 

promised. This created an urgent need to proceed to clean up contamination from the atoll. 

The JTG performed the cleanup using 6,000 personnel mostly from the U.S. Military 

Services with an additional small number of individuals from Field Command Defense Nuclear 

Agency (FCDNA). The JTG was assisted by contractors, the United States Atomic Energy 

Commission (AEC) and other agencies (DNA, 1981). Major cleanup activities included:

• Clearance of vegetation and removal of contaminated soil and debris 

• Transportation of contaminated soil and debris to disposal sites at the lagoon or Cactus crater 

on Runit Island 

• Demolition and removal of uncontaminated buildings and debris 

• Recovery and disposal of unexploded ordnance by explosive ordnance disposal teams

• Preparation of the atoll for resettlement.

1.1 Background 

Since 2017, 16 ECUP VA requests for dose assessments have been fulfilled by DTRA. 

The dose estimations were completed based on early development of a methodology later 

published in DTRA (2018). Most of the veterans in these requests were involved in work on the 

residence islands of Enewetak1 and Lojwa with occasional visits to northern islands with 

controlled access. Other veterans dealt with hauling contaminated soil and debris, repairing 

transport boats, performing radiological surveys in periods before and during cleanup operations, 

and Cactus dome construction. None of the total organ doses2 reported for these 15 veterans 

1 This report uses traditional island names; a cross-reference between island and site names is given in Table 4. 2 “Total organ dose” as used in this report means the sum of external and internal committed equivalent doses from 

all applicable exposure pathways.
2

exceeded 1 rem and most of them had upper-bound total organ doses in the 0.01 to 0.1 rem 

range. These doses are an order of magnitude or more below the U.S. federal occupational dose 

limits for radiation workers adopted by the ECUP (DNA, 1981).

In addition, the NTPR program developed standard operating procedure SOP RA06

(DTRA, 2021) to be used to prepare detailed RDAs for dose requests submitted by the 

Department of Veterans Affairs (VA) for ECUP veterans. The RDAs were based on participation 

scenarios found in the ECUP RDA technical report (DTRA, 2020) combined with statements in 

veteran-submitted questionnaires. In 2021, based on experience performing detailed RDAs, 

NTPR program analysts recommended that dose assessments for qualifying ECUP veteran 

claims could be expedited by assigning pre-estimated, group-based, upper-bound doses. As in 

other NTPR program components, the use of expedited processing procedures allows for timely 

processing of claims while ensuring that an individual veteran’s assigned doses are greater than 

his actual doses.

Furthermore, since 2008, the NTPR program has used an approved procedure to expedite 

the processing of RDAs for dose requests submitted by the VA for atmospheric nuclear weapons 

testing veterans with qualifying participant exposure scenarios. Dose assessments for qualifying 

claims from such veterans may be expedited using NTPR procedure SOP RA02 (DTRA, 2021)

by assigning pre-determined, group-based, upper-bound dose estimates to veteran claimants. In 

2015, an approved procedure, SOP RA05 (DTRA, 2021), was implemented to help expedite 

dose assessments for post-war occupation of Hiroshima and Nagasaki veterans. The use of 

expedited processing procedures allowed for timely processing of large numbers of claims while 

ensuring that an individual veteran’s assigned dose is greater than his actual dose. 

1.2 Purpose of ECUP Expedited Processing

The expedited processing of RDAs is based on specific criteria provided in this technical 

report. The implementation of expedited processing of RDAs will be documented in a standard 

operating procedure (SOP RA07) to be developed after the completion of this technical report. 

The SOP will include detailed instructions and criteria for expedited processing of dose 

assessments for ECUP veterans. Expedited processing would result in the assignment of upperbound, group-based radiation doses to ECUP veterans without the need for individualized RDAs. 

To create an expedited processing system for ECUP, Expedited Processing Groups (EPGs) are 

identified, and maximized upper-bound doses3 are estimated for each group. 

1.3 Scope of ECUP Expedited Processing 

Claimant cases for ECUP veterans are initially evaluated for eligibility for expedited 

processing and processed according to a detailed methodology described in the SOP to be 

developed for ECUP veterans. The doses assigned under expedited processing would be 

significantly lower than the threshold for a disease to have been as likely as not caused by 

radiation exposure and result in service connection for a claim. Cases that do not pass the 

eligibility criteria for expedited processing would require further technical review of the veteranspecific dose estimates or may necessitate preparing an individualized RDA performed in 

3 A “maximized upper-bound dose” represents an estimated dose that is higher than a 95 percent upper confidence 

limit dose for an exposure scenario in which parameter values are selected to maximize external and internal doses. 
3

accordance with SOP RA06 (DTRA, 2021). The methodology and dose estimates presented in 

this report apply to cases involving diseases covered under Title 38, Code of Federal 

Regulations, Part 3.311, Claims based on exposure to ionizing radiation (38 CFR 3.311).

1.4 Rationale for Developing an Expedited Processing Approach for ECUP RDAs 

The benefits of creating and implementing expedited processing for ECUP participants’ 

dose assessments include the following:

• De-emphasized focus of research on detailed participant activities which, if accounted for,

does not yield doses high enough for service connection for claimed diseases

• Reduced processing costs for RDAs because most RDAs involve assignment of upper-bound 

doses based on veterans participating in broadly defined occupation/work groups versus 

individualized detailed activities and exposure scenario assessments

• More timely response to VA requests and more timely decision-making for veterans’ claims 

than if veteran-specific, full RDAs were performed

• Options for conducting more detailed technical review and possibly an individualized RDA 

for ECUP cases that do not qualify for expedited processing under the exclusions specified in 

this report and related procedure.
4

2.

Methodology for the Development of an Expedited Processing Approach

for ECUP Participants

The general approach for EPG dose assessments was established previously by the 

process used to develop EPG scenarios and doses for atmospheric testing veterans and veterans 

of Hiroshima and Nagasaki (Case et al., 2011; McKenzie-Carter and Egbert, 2015). In this 

approach, maximized upper-bound doses are estimated for each EPG using dose-maximizing 

exposure scenarios that are applicable to large groups of participants. Dose-maximizing exposure 

scenarios, parameter values, and assumptions represent exposure conditions such as exposure 

duration and radiation source characterization that are well above what typical ECUP personnel 

experienced. This approach is intended to result in estimated maximized upper-bound doses that 

exceed the 95th percentile of any dose distribution actually received by ECUP participants. 

For ECUP expedited processing, EPGs are formed based on the types and locations of 

activities, related sources of exposure, and exposure pathways. For the ECUP EPGs, specific 

cohorts, units, or teams cannot be distinctly defined. This is in contrast with previous expedited 

processing assessments where each EPG was identified to include specific cohorts, such as 

crewmembers aboard specific ships in a test series or troops that participated in observing test 

detonations and maneuvering in forward test areas. 

2.1 Expedited Processing Concept

In the NTPR program, DTRA developed an expedited processing system for atmospheric 

testing veterans by which most veteran dose assessments are handled. In that system, doses are 

assigned for a veteran claim from pre-calculated doses that apply to various EPGs. Each EPG is 

defined by the cohorts or units that make it up so that any claimant can be uniquely placed in his 

applicable EPG. In most cases, the doses estimated for the applicable EPG are assigned to the 

veteran. 

Participants in ECUP did not perform activities that allows for defining EPGs based on 

specific cohorts or units. However, an expedited processing concept can be created that relies on 

a broad definition of the types of participant’s activities and their locations, sources of radiation, 

and exposure pathways. Using this concept, four ECUP EPGs are identified, and their 

characteristics are defined in a distinct manner as discussed in Section 3. 

To ensure that doses assigned to a veteran through expedited processing are higher than 

the veteran’s actual doses, EPG doses must satisfy the following major conditions: 

• The EPG doses are upper bounds of dose-maximizing exposure scenarios with respect to 

dose input parameter values and assumptions, not all of which the veteran may have actually 

encountered.

• The EPG doses are broadly applicable to large groups of veterans rather than doses estimated 

for individualized RDAs.
5

• The dose-maximizing assumptions are designed to produce maximized upper-bound doses 

that are higher than 95th percentile doses that would be estimated in individualized ECUP 

RDAs for any member of an EPG.

• The EPG doses, although not necessarily the absolute maximum possible, are high enough to 

ensure that the assigned doses exceed a veteran’s true upper-bound (95th percentile) dose.

With these criteria, individual veteran claimants whose doses are assigned by expedited 

processing can be assured that the assigned doses are higher than their actual doses including all 

known uncertainties. In addition, if more than one EPG applies to a veteran, the one that results 

in higher assigned doses should be selected. This approach should always prevail in expedited 

processing to provide the utmost benefit to a veteran.

2.2 Confidence in Assigned EPG Doses

As discussed above, when using expedited processing for assigning doses to individual 

veterans, the process must clearly show that the assigned doses are greater than the actual doses

that any member of the group could have received. Achieving this goal requires the use of many 

dose-estimating factors that reflect worst-case scenarios, such as the veteran’s specific activities 

that could have resulted in exposure to radiation, the characteristics of the radiation environment, 

and the uncertainties in the parameters used in the EPG dose calculations. 

The doses produced for expedited processing are adequate for submission to VA when 

they are maximized and are well below the doses that result in a probability of causation (PC) for 

a specific cancer of 50 percent, called screening doses. As has been done in previous DTRA 

expedited processing assessments developed for other veteran populations, it is recommended 

that ECUP EPG total organ doses correspond to an estimated probability of causation that is no 

higher than 40 percent. This recommendation is intended to provide an additional margin of 

confidence and to ensure suitability of the doses for use in ECUP expedited processing. Doses 

corresponding to a 40 percent probability of causation are referred to as Limiting Doses (LD); 

these doses are discussed further in Section 2.6.1. (DTRA, 2021, SOP RA02; McKenzie-Carter 

and Egbert, 2015)

2.3 Suitability of EPG Doses

During the development of the EPG approach, it was recognized that some EPG doses, 

which are maximized using the methodology described in this section, could be near or above the 

doses that would result in a service-connection determination by the VA. Such doses would not 

be suitable for use in support of VA’s claim decisions. Therefore, a review of EPG doses to 

determine their suitability for assignment to individual participants must be accomplished to 

identify organs associated with those doses. Further discussion on EPG doses that are not 

suitable for assignment is provided in Section 2.6.1. 

2.3.1. Internal Organ and Skin Doses

EPG doses for specific organs or skin cancer sites are suitable for assignment in veteran 

cases when the total organ or skin dose for an EPG is well below the screening dose, which is the 
6

dose corresponding to a probability of causation of an organ or skin cancer of 50 percent. To 

identify doses that may not be suitable, total organ and skin doses for all EPGs are compared to 

the applicable limiting doses, which produce an estimated probability of causation of about 

40 percent using the NIOSH-IREP software application (NIOSH, 2020).

If an EPG total organ dose, which is the sum of the maximized upper-bound external and 

internal doses, is higher than the limiting dose of the corresponding NIOSH-IREP cancer model, 

the external and internal upper-bound doses estimated for the EPG/organ combination are 

deemed not suitable for assignment by expedited processing. If an EPG total organ dose is lower 

than the corresponding limiting dose, then the external and internal doses for the EPG/organ 

combination are suitable and are proposed for use in expedited processing of ECUP veteran 

cases. 

The same approach is used for determining the suitability of assigning skin doses by 

expedited processing for the selected EPGs. Results of the EPG dose estimates and comparison 

with the limiting doses are discussed in Section 5.

2.3.2. Lens of the Eye Doses

Unlike EPG doses for internal organs and skin that are generally estimated for 

assignment in cases involving cancers, doses to the lens of the eye are estimated for use in cases 

involving posterior subcapsular cataracts (PSCs, or “cataracts”). Because cataracts are not a 

cancer, the concept of an LD discussed above is not applicable. However, cataracts are a 

deterministic effect for which a “threshold dose” can be estimated. For cataracts, the threshold 

dose is the lowest radiation dose that is expected to result in cataracts. 

A threshold dose for cataracts can be used to determine the suitability of assigning a dose 

to the lens of the eye through expedited processing. A threshold dose of 35 rad has been cited by 

the VA as the “maximum likelihood dose” for Stage I PSCs with an associated 95 percent 

confidence interval of 19–66 rad (VA, 2011). For ECUP expedited processing, the lower limit of 

this confidence interval is proposed as a threshold dose for comparison with an estimated

maximized upper-bound dose to the lens of the eye. Therefore, if the total dose to the lens of the 

eye is lower than 19 rad, it is suitable and is proposed for use in expedited processing of ECUP 

veteran cases. Results of the ECUP EPG lens of the eye dose estimation and comparison with the 

threshold dose are discussed in Section 5. 

2.4 Criteria for Selecting ECUP Expedited Processing Groups

Each EPG, discussed in Section 3, includes ECUP participants whose actual activities 

would have resulted in total doses that are lower than the EPG total organ doses. The aim is to 

set EPG selection criteria so that all possible exposure pathways and radiation sources are used 

to estimate the EPG’s external and internal doses. In addition, it is important that each EPG and 

corresponding doses can be applied to a relatively large number of participants. Therefore, to 

identify coherent EPGs, the following criteria should apply to all members of an EPG:

• Commonality of activities and radiation environments

• Similarity of exposure pathways that contribute the most significant doses
7

• Comparability of types of radiation, e.g., external gamma, internal alpha, and internal 

beta/gamma radiation

• Similarity of durations of participation and exposure 

• Likelihood that total organ doses, i.e., external plus internal doses, are well below the 

screening doses for all or most applicable cancers.

In general, use of the above criteria along with the conditions specified in Section 2.1

results in EPGs and corresponding doses that can be assigned to most ECUP participants. To 

accomplish this goal, four EPGs were identified and are described in Section 3. 

2.5 Experience Performing ECUP Radiation Dose Assessments

In late 2017, the first ECUP veteran case RDA that was performed by the NTPR Program 

was used as one of several sample cases assessed as part of the development of the ECUP RDA 

technical basis document published in April 2018 (DTRA, 2018). Subsequently, cases were 

assessed using the methods, data, and results reported in the ECUP RDA draft and final technical 

report (DTRA, 2018). Based on the findings published in the ECUP RDA technical report, the 

NTPR team developed a standard operating procedure (SOP RA06) that was published on 

DTRA’s NTPR website in December 2019. It included approved instructions on conducting 

ECUP RDAs and the dose default parameter values to be used in estimating veteran doses 

requested by the VA. 

In total, since 2017, 16 ECUP VA requests for dose assessment have been fulfilled by 

DTRA’s NTPR Program team. Most of these cases involved veterans who worked on the 

residence islands of Enewetak and Lojwa with occasional visits to northern islands with 

restricted access. These participants were involved in activities such as operational 

administration, supply management, air transportation, central communications, analytical 

laboratory testing, and mobilization/demobilization support. Other veterans conducted activities 

including hauling contaminated soil and debris, repairing transport boats, surveys in periods 

before and during cleanup operations, and encapsulation of contaminated soil and debris in 

Cactus crater on Runit Island.

Some of the cases completed are for veterans who were at Enewetak Atoll during the 

ECUP for a short period, from a few days to a couple of weeks. These cases involved support by 

transient ships that visited Enewetak Atoll to perform maintenance and repair of small boats, 

deliver supplies and equipment, pick up retrograde cargo, etc. Crewmembers of transient ships 

typically remained on their ships in the lagoon and spent little or no time on the islands and their 

estimated total organ doses were much lower than those estimated for other participants. 

Visitors to the northern islands of Enewetak Atoll, where access was often controlled, 

were issued one or more film badges (FB) or thermoluminescent dosimeters (TLD). Because the 

low doses recorded by FBs were at or below the minimum detectible level of 0.020 rem, dose 

reconstruction in all such cases was performed (DTRA, 2020). 

In general, scenarios of exposure were characterized by similar types of radiation sources 

and pathways as follows:
8

• External radiation exposure to the whole body

• Inhalation of contaminated soil and dust generally suspended from ground surfaces

• Incidental ingestion of soil and dust from inadvertent intake by mouth of small quantities of 

soil and dust particles that adhered to food, beverages, cigarettes, or hands

• Ingestion by consumption of potentially contaminated local foods.

Overall, none of the total organ doses estimated for the 16 veterans exceeded 1 rem and 

most of them had upper-bound total organ doses in the 0.01 to 0.1 rem range. These doses are an 

order of magnitude, or more, lower than the U.S. Nuclear Regulatory Commission (USNRC)

occupational dose limits for radiation workers that were adopted by the ECUP (DNA, 1981).

2.6 Exclusion from Expedited Processing

2.6.1. Exclusion Based on Exceedance of Limiting Doses

It is possible that organ or skin doses calculated for ECUP EPGs using the conservative 

methodology described above could be near or above the level that could lead to serviceconnection determinations, if used by the VA. To be suitable for assignment, upper-bound total 

organ doses that result from the expedited processing approach described in this section must be 

well below the dose that could result in service-connection. Consistent with previous expedited 

processing assessments (Case et al., 2011; McKenzie-Carter and Egbert, 2015), the dose defined 

as “well below the dose that could result in compensation” is the dose that produces a probability 

of causation for cancers of 40 percent at the upper 99 percent credibility limit for an acute 

exposure at age 18 years, and diagnosis of cancer at either age 50 years or after an appropriate 

elapsed time following exposure. This dose is defined as the “Limiting Dose” (LD) for each 

organ or skin cancer model and is compared with the corresponding total organ or skin dose 

estimated for each ECUP EPG and reported in Section 5. 

Values of LDs for cancers of internal organs assuming all (external and internal) doses 

are acute doses from photons with energy greater than 250 keV (LDγ) were previously estimated

using the NIOSH-IREP application (NIOSH, 2020). These LDγ values are reported in SOP 

RA02 (DTRA, 2021), and are also shown in Table 1. However, for some ECUP EPG and organ 

combinations, the dose from alpha radiation is the major contributor to the total dose. To account 

for these occurrences, LD values calculated by assuming that the total dose is from alpha 

radiation (LDα) were estimated using the NIOSH-IREP application and are shown in Table 1. 

Acute exposures to alpha radiation were assumed in estimating LDα values to produce 

conservative (lower) LDα values for most organs/diseases. In Section 5, these limiting doses 

(LDα) are those used to determine exclusions from expedited processing. 

Like internal organ doses, LDγ for three types of skin cancers were previously 

determined using input to NIOSH-IREP that assumed that doses were acute doses from photons 

with energy greater than 250 keV. In addition, skin cancer LDγ were estimated assuming

exposure at age 18 years and attained age of 50 years at the time of cancer diagnosis. However, 

like internal organ doses, some of the estimated EPG skin doses include a large contribution 

from alpha radiation, which is due to the highly conservative exposure model used for estimating 
9

dermal contamination skin doses. To account for these occurrences, LDα values based on the 

assumption that the total skin dose is due to alpha radiation were estimated. Furthermore, LDs 

for the three types of skin cancers vary according to the race of an individual. The LD values in 

this report were estimated for the five race categories included in NIOSH-IREP: “American 

Indian or Alaska Native,” “Asian, Native Hawaiian, or other Pacific Islander,” “Black,” “White, 

Hispanic,” and “White, Non-Hispanic.” All LD values for the three types of skin cancers are 

shown in Table 2.

As reported in Section 5, the EPG total organ doses (TODs) were calculated by adding 

the maximized upper-bound external dose and the maximized upper-bound internal doses (alpha 

and beta+gamma doses) for 24 organs for which ICRP 68 dose coefficients are available. Also, 

maximized upper-bound external doses (alpha+beta+gamma) were calculated for 17 

representative skin sites and the lens of the eye (beta+gamma). When the EPG TOD or the total 

maximized upper-bound skin dose exceeds the applicable LDα, expedited processing is not 

recommended for the specific veteran’s claim. Cases involving an EPG/organ combination or an 

EPG/skin cancer combination that is found to be unsuitable for expedited processing should be 

referred for further evaluation by an RDA analyst; guidance will be included in a standard 

operating procedure to specify how these cases are processed. 

In addition, any organs or skin cancers that do not have associated LDα values listed in 

this report are not recommended for expedited processing unless surrogate organs or skin sites 

are identified. The TODs and total upper-bound skin doses that exceed the applicable LDα are 

presented in Table 15 to Table 17.

Some ECUP standard organs are used for more than one tissue or organ, some of which 

have different LDα values. For example, liver is the surrogate organ for gallbladder (LDα = 

6.5 rem) but the LDα for liver cancer is 3.6 rem. Similarly, ET Region is the surrogate organ for 

larynx (LDα = 48 rem), and several tissues and organs in the oral cavity such as tongue, parotid 

gland, and pharynx (LDα = 36 rem). In these cases, the lowest of these multiple LDα values for 

any standard organ is the LDα that is compared to the ECUP EPG dose for each organ in 

subsequent sections. For example, the LDα used for liver is 3.6 rem (the lower of 6.5 and 

3.6 rem), and the LDα used for ET Region is 36 rem (the lower of 36 and 48 rem). 
10

Table 1. Limiting doses for cancers based on all alpha or all photon radiation

Cancer of Organ/Disease LDα* (rem) LDγ† (rem)

Acute Lymphocytic Leukemia (ALL) 20‡ 14‡

Acute Myeloid Leukemia (AML) 15‡ 20‡

All digestive, other than excluding esophagus, 

stomach, colon, rectum/anus 17 44

Bone 15 32

Breast (male) 10 36

Breast (female) 15 39

Chronic Lymphocytic Leukemia (CLL) 34‡ 45‡

Chronic Myeloid Leukemia (CML) 89‡ 41‡

Colon 11 26

Connective tissue 17 34

Endocrine glands, other than thyroid 12 30

Esophagus 11 22

Eye 16 32

Female genitalia 1400 1000

Gallbladder 6.5 11

Leukemia, other than ALL, AML, CML, and CLL 27‡ 29‡

Liver 3.6 7.7

Lung (never smokers) 13 30

Lymphoma and multiple myeloma 28 41

Male genitalia 30 41

Nervous system 37 64

Oral cavity and Pharynx 36 66

Other and ill-defined sites 17 34

Ovary 14 25

Pancreas 34 61

Rectum 43 72

Respiratory tract, other than lung 48 67

Stomach 10 18

Thyroid 3.2§ 5.1§

Urinary Bladder 16 33

Urinary organs, other than bladder) 13 31

* LDα = Limiting dose (PC of 40 percent) assuming the total organ dose is due entirely to alpha 

radiation. LDα values were estimated with the NIOSH-IREP online software. Assumptions include 

acute exposure at age 18 years and attained age of 50 years (elapsed time of 32 years) unless noted 

otherwise. Values are for males except values for three female-specific organs listed.

† LDγ = Limiting dose (PC of 40 percent) assuming the total organ dose is due entirely to photon 

radiation > 250 keV. LDγ values are from DTRA (2021, SOP RA02) except values for three femalespecific organs listed. All LDγ values were calculated using the NIOSH-IREP software as described 

in the footnote above.

‡ LDα and LDγ values for leukemia are calculated for an elapsed time of 30 years.

§ LDα and LDγ values for thyroid cancer are calculated for an elapsed time of >10 years.
11

Table 2. Limiting doses for skin cancers assuming all alpha or all photon radiation

LDα* (rem) LDγ* (rem)

NIOSH-IREP Race Category MM† BCC† SCC† MM† BCC† SCC†

American Indian or Alaska 

Native 1.0 0.85 63 2.1 1.7 89

Asian, Native Hawaiian, or 

other Pacific Islander 1.8 0.85 63 3.6 1.7 89

Black 1.7 0.85 63 3.5 1.7 89

White - Hispanic 2.1 2.4 165 3.9 4.0 188

White - Non-Hispanic 2.4 2.5 175 4.1 4.1 190

* – LD values correspond to a PC of 40 percent. LD values are estimated with the on-line NIOSH-IREP software

(NIOSH, 2020), using an acute exposure at age 18 and cancer diagnosis at age 50. 

– LDα is estimated by assuming the total skin dose is due entirely to alpha radiation.

– LDγ is estimated by assuming the total skin dose is due entirely to photons with energies > 250 keV.

† MM = malignant melanoma; BCC = basal cell carcinoma; SCC = squamous cell carcinoma.

2.6.2. Exclusion Based on Unusual Participation or Exposure Scenario

In the previous subsection, the exclusion of EPG/organ combinations from expedited 

processing that are driven by the EPG total organ dose exceeding the applicable LD were 

discussed. In addition to those exclusions, exclusion from expedited processing when a veteran’s 

scenario of participation and radiation exposure cannot be categorized to fit any of the ECUP 

EPG characteristics discussed in Section 3. Excluded cases require a more detailed case review 

and dose assessment

Unusual participation and exposure scenarios may involve sources of radiation or 

pathways that are not included or only partially covered by any of the four ECUP EPGs dose 

components. By “not covered”, it is meant that any dose resulting from the unusual scenario 

cannot be accounted for within any of the exposure pathways considered for any of the four 

EPGs. 

Situations that could be considered unusual may involve veterans who only spent short 

periods at the atoll and were not stationed on any of the islands, e.g., Navy crews that remained 

aboard their ships that were anchored in the lagoon and personnel who flew in supplies and 

personnel and were at the atoll for only a limited time away from contaminated areas. Specific 

examples of exclusions based on unusual participation and exposure scenarios are given in 

Section 3.

Although, these unusual types of participation would result in actual doses that are likely 

lower than any EPG doses, any relevant cases should be processed differently from those that 

can be assigned to one of the four EPGs. Guidance on the treatment of such cases will be 

included in the standard operating procedure on ECUP expedited processing of veteran RDAs.
12

3.

Identification and Selection of Expedited Processing Groups

This section describes the basis for sorting the ECUP participant population into groups 

appropriate for expedited processing. The radiation exposure scenarios of members of the 

population are broken out by radiation sources and exposure pathways. Together, the applicable 

populations are allocated to four EPGs based on the application of selection criteria in Section 2. 

Each EPG is fully described by common activities in which selected subpopulations were 

involved. Finally, ECUP activities that may not fit into the EPG scenarios are identified.

3.1 Participant Population and General Radiation Exposure Scenarios

3.1.1. Potentially Exposed Population

The management of the ECUP operations was assigned to a Joint Task Group (JTG) that 

was responsible for all aspects of the cleanup operations on Enewetak. The JTG was staffed by 

nearly 6,000 individuals from the U.S. Army, U.S. Navy, and U.S. Air Force in five divisions 

that reported to the Commander of JTG (CJTG). The CJTG was also given supervisory authority 

for direction and control over the Military Service components of the JTG. The total number of 

participants and units composing the Military Service elements and the FCDNA JTG that make 

up the ECUP participation population are shown in Table 3. (DNA, 1981) 

Table 3. Military Service element and DNA/JTG staffing of the Enewetak Cleanup Project

U.S. Army Element U.S. Navy Element U.S. Air Force Element FCDNA/JTG

2,670 2,207 740 246

• Engineer Units

• Helicopter Team

• LARCs and 

amphibious vehicle 

operations

• Chaplain Team

• Finance Team

• General Laundry 

Team

• Decontamination 

Laundry

• Harbor Clearance 

Units and WaterBeach Cleanup 

Teams

• Intra-atoll 

Transportation

• Radiological and 

laboratory 

technicians

• Field Radiation Support 

Team

• Medical Team

• Radiological and lab 

technicians

• Communicationselectronics Team

• Petroleum-oil-lubricants 

Team

• Airfield Team

• Postal Team

• Commander, JTG

• Administration

• Engineering

• Radiological 

Control

• Logistics

• Security
13

3.1.2. Radiation Sources and Exposure Pathways

Sources of radiation that may have resulted in exposure of ECUP participants to radiation 

include:

• Fallout mixed in the top layer of soil of contaminated islands

• Stockpiles of contaminated soil and debris

• Contaminated soils and debris during transport by trucks and boats

• Contaminated concrete slabs and building debris

• Slurry of mixed contaminated soil and cement, during preparation, transport and disposal in 

the Cactus crater

• Soil-cement mix produced and contained in the Cactus dome 

• Lagoon and ocean waters, while retrieving debris and during recreational diving or 

swimming

• Contaminated equipment and decontamination laundry.

In general, an exposure pathway is the route followed by radiation or contaminants from 

a source, via air, soil, water, or food to a human receptor. Participants in the ECUP were 

potentially exposed to external gamma and beta radiation and internal radiation from the intake 

of radioactive materials by inhalation and ingestion, or through wounds. In the context of the 

ECUP and potential exposure to radiation, pathways involve exposure of the whole body to 

gamma radiation from external sources, inhalation of airborne contaminants, ingestion of 

contaminated foods, and exposure of the skin and lens of the eye to external sources of gamma 

and beta and alpha radiation. The radionuclides of concern in these pathways are Sr-90, Cs-137, 

Co-60, Pu-239/240, and Am-241. (DTRA, 2020)

Exposure from contaminated ground surfaces or debris was the most likely potential 

external radiation exposure pathway for ECUP participants. This external exposure pathway 

applies to participants who were working or residing on islands, whether involved in cleanup 

activities or not. The potential inhalation of soil that was excised, windrowed, stockpiled, and 

transported for ultimate containment in Cactus crater on Runit Island represents an internal 

exposure pathway for individuals who were involved in soil cleanup activities. Inhalation of 

suspended contaminated soil during other activities was the most likely internal radiation 

exposure pathway for other ECUP participants. A more detailed discussion of sources of 

radioactive contaminants and exposure pathways during the ECUP can be found in Section 5 of 

DTRA (2020). 

Exposure of the skin to external sources of gamma and beta and alpha radiation could 

have occurred from the same sources listed above. In addition, exposure of the skin could have 

occurred if contaminated soil and dust were deposited directly on the skin or clothing.

3.2 Expedited Processing Groups and Applicable Exposure Scenarios

Four EPGs were selected based on the criteria presented in Section 2. For each EPG, 

potential exposure pathways, radiation environments, and participant activities were based on 
14

specific assumptions and parameter values allowing the development of maximized doses. Each 

EPG was defined to represent a sizeable population of ECUP participants that were engaged in 

common activities and experiencing similar radiation exposure environments at worksites. The 

selected EPGs are discussed below. 

3.2.1. Soil Removal Workers EPG

Members of this EPG are ECUP participants who performed activities involving 

disrupting and handling contaminated soil that required removal from the five northern islands of 

Boken, Enjebi, Lujor, Aomon, and Runit. These islands were identified by DNA as requiring 

cleanup by soil removal, transport to Runit Island, and disposal in Cactus crater (DNA, 1981).

These islands are located in the north rim and in the northeast quadrant of the atoll as shown in 

Figure 1.

Personnel included in this EPG are assumed to have resided on Lojwa Island while 

performing cleanup work on the northern islands for their entire assignment. These personnel

performed several activities involving disrupting and handling contaminated soil. Sample 

activities that could have been performed by individuals that would be members of this EPG 

include, but are not limited to, the following:

• Digging, excavating, moving, stockpiling soil

• Loading soil into dump trucks, boats, and vehicles of any kind using heavy machinery

• Transporting soil to Runit

• Unloading soil 

• Gathering and reforming the soil into other media for disposal, such as soil-cement slurry 

by-products from the tremie system

• Moving soil or reformed soil to the disposal site for containment.

3.2.2. Northern Island Workers EPG

This EPG includes personnel whose primary work assignment involved work on one or 

more of the northern islands (except Lojwa) for their entire assignment. These workers may have 

been involved in earthmoving activities on a limited or occasional basis but they were not 

involved in directly disrupting and handling contaminated soil that required excision, 

transportation, and disposal, such as in the Soil Removal Workers EPG. Refer to Section 4 for 

discussions on accounting for these activities. The 21 northern islands included in this EPG are 

listed in Table 4, and consist of the line of islands starting with Bokoluo in the northwest 

clockwise along the northern and northeast rim of the atoll to Runit, excluding Lojwa (see 

Figure 1). These personnel typically resided on Lojwa Island. Sample work activities that would 

have been performed by members of this EPG include, but are not limited to, the following: 

• Handling contaminated and uncontaminated debris

• Preparing debris for transport

• Accompanying debris during transport
15

• Unloading, moving, and disposing of yellow debris at lagoon disposal sites and red debris in 

the crater

• Performing radiological monitoring, sampling, and inspections 

• Removing brush.

Figure 1. Islands of Enewetak Atoll (Adapted from DNA (1981))
16

Table 4. Enewetak Atoll islands

Island 

Code* Site Name Island Name†

Northern Islands

FA Alice Bokoluo

FB Belle Bokombako

FC Clara Kirunu

FD Daisy Louj

FE Edna Bocinwotme

FH Helen Bokaidrik

FI Irene Boken

FJ Janet Enjebi

FK Kate Mijikadrek

FL Lucy Kidrinen

MP Percy Taiwel

FM Mary Bokenelab

FN Nancy Elle

FO Olive Aej

FP Pearl Lujor

FR Ruby Eleleron

FS Sally Aomon

FT Tilda Bijile‡

FU Ursula Lojwa

FV Vera Alembel

FW Wilma Billae

FY Yvonne Runit

Southern Islands

MS Sam Boko

MT Tom Munjor

MU Uriah Inedral

MV Van ―§

MA Alvin Jinedrol

MB Bruce Ananij

MC Clyde Jinimi

MC David Japtan

MR Rex Jedrol

ME Elmer Medren (aka Parry)

MW Walt Bokandretok

MF Fred Enewetak

MG Glenn Ikuren

MH Henry Mut

MI Irwin Boken

MJ James Ribewon

MK Keith Kidrenen

ML Leroy Biken

MO Oscar (coral head) Drekatimon

MM Mack (coral head) Unibor

* Island codes were assigned by the JTG.

† For further reference, refer to Section 2 of DTRA (2020).

‡ Shown as Bijire in DNA (1981).

§ The Enewetak people had no name for this island.
17

3.2.3. Lojwa Island Support Workers EPG

Members of this EPG include personnel whose primary work assignment and residence was on 

the island of Lojwa. These are generally identified as support personnel maintaining the Lojwa 

island infrastructure and services that supported cleanup operations. Sample work activities 

associated with this EPG include, but are not limited to, the following:

• Maintaining instrumentation, analyzing samples, and decontaminating clothing at on-site 

facilities

• Maintaining the facilities and structures

• Installing and maintaining telecommunication systems

• Supporting petroleum, oil, and lubrication stores to supply other northern islands

• Operating postal, food, and welfare and recreation services

• Transporting workers to and from cleanup sites

• Producing potable and drinking water and operating desalination systems

• Running laundry services

• Providing medical and dental care.

3.2.4. Southern Island Workers EPG

Individuals that can be assigned to this EPG include personnel whose primary work assignment 

involved work on one or more of southern islands. The southern islands included in this EPG are 

listed in Table 4 and are shown in Figure 1. The southern islands comprise the line of islands 

starting with Boko in the eastern rim of the atoll south of Runit, continuing clockwise along the 

southern rim of the atoll and ending with the island of Biken. Personnel included in this EPG 

resided for the most part on Enewetak Island. Sample activities associated with work performed 

on the southern islands by members of this EPG include, but are not limited to, the following:

• Performing command, control, and communication functions

• Providing central logistical support to the cleanup 

• Performing project management and administration

• Constructing and maintaining buildings and structures

• Preserving petroleum, oil, and lubrication stores

• Providing medical and dental care 

• Installing and maintaining telecommunication systems

• Operating the postal, food, and welfare and recreation services

• Transporting other personnel and materials during MEDEVAC and SAR missions

• Performing gross radiological islands surveys
18

• Supplying/resupplying the northern residence island of Lojwa

• Removing contaminated soil from Medren

• Removing uncontaminated debris 

• Removing unexploded ordnance

• Conducting mobilization and demobilization activities.

3.3 Potential Exclusion from Expedited Processing Consideration

Several activities may have resulted in exposure scenarios that may not fit within the 

EPG definitions given above. They may include:

• Removing plutonium fragments removal from burial crypts on Aomon

• Disposing soil bags with plutonium fragments from Fig-Quince on Runit

• Removing concentrated contaminated material from outside of the bunkers on Boken

• Repairing or maintaining contaminated equipment removed from controlled areas

• Participating in duties at the Decontamination Laundry Facility on Lojwa Island

• Participating in RSAIT inspection activities

• Consuming local foods in excess of what is assumed for estimating EPG doses

• Being involved in or near accidents or abnormal events involving contaminated soil or debris

• Being present at Enewetak Atoll for only a short time, e.g., DoD VIP visitors, or military 

personnel on transient ships or transport aircraft

• Having an ECUP assignment at Enewetak Atoll for greater than one year. 
19

4.

Maximizing Exposure Scenarios and Dose Parameter Assumptions

To estimate expedited processing doses for ECUP military participants, four generic 

groups of personnel were defined based on similarity of work location and activity (see 

Section 3). These four expedited processing groups (EPGs) encompass the majority of ECUP 

participants. For each EPG, maximizing exposure scenarios were developed based on activities 

and work locations that would result in TODs for the EPG that are clearly greater than any actual 

veteran TOD. Radiation doses estimated for the maximizing scenarios are calculated to be higher 

than any member of the EPG actually received. Exposure scenarios discussed in this section 

include sources of exposure, associated exposure pathways, and exposure times for external and 

internal radiation dose estimates. 

The following subsection describes the exposure scenarios to maximize the doses for 

each EPG. This is followed by descriptions of the parameters and the values used to estimate 

expedited processing doses for external, internal, skin, and lens of the eye for each EPG.

4.1 Exposure Scenarios 

This section describes potential exposure sources and exposure pathways for each EPG. 

A scenario is then described for each EPG that is based on a subset of these sources and 

pathways and maximizing parameter assumptions.

4.1.1. Soil Removal Workers EPG

This EPG includes personnel whose primary duties involved working directly with or 

near soil removal activities on one or more of the five northern islands of Boken, Enjebi, Lujor, 

Aomon, and Runit, where soil was excised and taken to Runit for containment in the Cactus 

crater. As described in Section 3, soil removal activities involved excising, windrowing, 

stockpiling, loading/unloading, transporting, and mixing soil for containment in the Cactus dome 

or containment cap. Typical members of this EPG would include, but are not limited to, U.S.

Army Engineer heavy equipment operators, soil transport truck drivers, crew of boats that 

transported soil, tremie workers and soil-cement mix teams on Runit.

The primary potential sources of external whole-body exposure for members of this EPG 

are as follows: 

• Fallout mixed in the soil on contaminated islands

• Stockpiled and windrowed contaminated soil

• Contaminated soil, during loading, transport, or unloading

• Slurry of mixed contaminated soil and cement

• Contaminated concrete slabs and debris, during handling, transport, or disposal

• For skin and lens of the eye, contaminated soil deposited directly on the skin or clothing.
20

The primary potential sources and intake routes of internal exposure for members of this 

EPG are as follows: 

• Inhalation of contaminated and excised soil suspended during soil removal activities 

• Inhalation of contaminated and excised soil suspended during soil-handling and transport

• Inhalation of suspended soil on residence islands

• Ingestion of locally sourced foods

• Incidental ingestion of contaminated soil and dust.

The exposure scenario used to maximize doses for this EPG is represented by workers 

who performed soil removal activities for an entire assignment on one or more of the five 

northern soil-cleanup islands of Boken, Enjebi, Lujor, Aomon, and Runit, where soil was excised 

because of its transuranic (TRU) element content. This scenario includes the assumption of 

excised and subsequently suspended soil contaminated with elevated levels of TRU. Full 

workday exposures for an entire 12-month ECUP assignment are also assumed. 

The maximized external exposures to the whole-body, skin, and lens of the eye for this 

EPG scenario involve exposure to contaminants in the top layer of soil on one of the five 

contaminated islands on all workdays. Continuous exposure to this source bounds potential 

exposures to other sources, such as contaminated debris (DTRA, 2020). Maximized daily 

exposure of skin to dermal contamination consisting of excised soil is also included. 

The maximizing internal exposure pathways include inhalation of airborne excised soil 

during the workday, with an assumed constant airborne mass loading approximately 15 times 

greater than the estimated ambient dust loading of 40 μg m−3 for the atoll (AEC, 1973). In 

addition, inhalation of suspended soil during all outdoor off-duty hours on Lojwa, consumption 

of local food, and incidental ingestion of contaminated soil and dust while on Lojwa are 

included. 

Parameter values used for estimation of external whole body doses, internal organ doses, 

external skin doses, and external doses to the lens of the eye resulting from the sources and 

pathways described above for the maximizing scenario of the Soil Removal Workers EPG are 

presented in Sections 4.2 and 4.3.

4.1.2. Northern Island Workers EPG

This EPG includes personnel whose primary duties involved working on northern islands 

of the atoll other than the five soil removal islands. These islands comprise the islands from 

Bokoluo clockwise around the northern portion of the atoll to Runit. The residence island of 

Lojwa where members of this EPG were billeted is not considered a work island for this EPG.

Because more fallout occurred on the northern islands during the atmospheric testing period, the 

external dose rates and soil radionuclide concentrations were generally significantly higher on 

the northern islands than on the southern islands. As described in Section 3, activities of 

members of this EPG involved removing, handling, and transporting debris, regular performance 

of radiological safety monitoring or sampling, and brush removal work. These personnel may 
21

have also occasionally handled contaminated soil. Typical members of this EPG would include, 

but are not limited to, members of U.S. Army Engineer Units, U.S. Navy Harbor Clearance Units 

and Water-Beach Cleanup Teams, and U.S. Air Force Field Radiation Support Teams.

The primary potential sources of external whole-body exposure for members of this EPG 

are as follows: 

• Fallout mixed in the top layer of soil on contaminated islands

• Contaminated concrete slabs and debris during handling, transport, or disposal

• Stockpiled and windrowed contaminated vegetation and debris

• Samples of contaminated soil during sampling and handling 

• Lagoon and ocean waters, while retrieving or disposing debris 

• Contaminated equipment

• For skin and the lens of the eye, contaminated soil deposited directly on the skin or clothing.

The primary potential sources and intake routes of internal exposure for members of this 

EPG are as follows: 

• Inhalation of contaminated soil suspended during work activities on one or more of the 

northern islands

• Inhalation of suspended soil on residence islands

• Ingestion of locally-sourced foods

• Incidental ingestion of contaminated soil and dust 

• Inadvertent ingestion of lagoon or ocean water while extracting offshore debris or swimming.

The exposure scenario used to maximize doses for this EPG is represented by workers 

who performed cleanup or support work on one or more of the northern islands other than the 

five soil removal islands and Lojwa for their entire assignment. This involved activities such as 

debris and brush removal including the use of heavy equipment that suspended contaminated 

soil. Full workday exposure for an entire 12-month ECUP assignment is also assumed. 

The maximized external exposures to the whole-body and skin for this EPG scenario 

involve exposure to contaminants in the top layer of soil on one or more of the northern islands 

on all workdays. Continuous exposure to this source bounds potential exposures to other sources, 

such as contaminated debris (DTRA, 2020). Maximized daily exposure of skin to dermal 

contamination from northern island soils is also included.

The maximizing internal exposure pathways include inhalation of airborne contaminated 

soil on one or more of the northern islands on all workdays, with an assumed constant airborne 

mass loading approximately 7.5 times greater than the estimated ambient dust loading of 

40 μg m−3 for the atoll (AEC, 1973). In addition, inhalation of suspended soil during all outdoor 
22

off-duty hours on Lojwa, consumption of local food, and incidental ingestion of contaminated 

soil and dust while on Lojwa are included. 

Parameter values used for estimation of external whole body doses, internal organ doses, 

external skin doses, and doses to the lens of the eye resulting from the sources and pathways 

described above for the maximizing scenario of the Northern Island Workers EPG are presented 

in Sections 4.2 and 4.3. 

4.1.3. Lojwa Support Workers EPG

This EPG includes personnel whose primary job during the ECUP involved working on 

Lojwa Island. As described in Section 3, activities of members of this EPG generally involved 

maintaining the island’s infrastructure that supported the cleanup operations. Typical members of 

this EPG would include, but is not limited to, members of U.S. Army Engineer Units, U.S. 

Army, U.S. Navy, and U.S. Air Force providers of support services such as laundry, finance, 

laboratory technician, medical, postal, and communication services.

The primary potential sources of external whole-body exposure for members of this EPG

are as follows:

• Fallout mixed in the top layer of soil on Lojwa

• Contaminated equipment and laundry

• Samples of contaminated soil

• For skin and the lens of the eye, contaminated soil deposited directly on the skin or clothing.

The primary potential sources of internal exposure and intake routes for members of this 

EPG are as follows: 

• Inhalation of contaminated soil suspended by routine activities such as vehicle traffic

• Ingestion of locally-sourced foods

• Incidental ingestion of contaminated soil and dust 

• Inadvertent ingestion of lagoon or ocean water while swimming.

The exposure scenario used to maximize doses for this EPG is represented by workers 

whose regular duty was performed primarily on Lojwa for an entire assignment. Full workday 

outdoor exposures on Lojwa for an entire 12-month ECUP assignment is assumed. 

The maximized external exposures to the whole-body and skin for this EPG involve 

exposure to contaminants in the top layer of soil on Lojwa on all work and non-workdays. 

Continuous exposure to this source bounds potential exposures to other sources, such as 

contaminated debris (DTRA, 2020). Maximized daily exposure of skin to dermal contamination 

from Lojwa soil is also included.
23

The maximizing internal exposure pathways include inhalation of suspended soil during 

all duty and outdoor off-duty hours on Lojwa, consumption of local food, and incidental

ingestion of contaminated soil and dust on Lojwa. 

Parameter values used for estimation of external whole body doses, internal organ doses, 

external skin doses, and lens of the eye doses resulting from the sources and pathways described 

above for the maximizing scenario of the Lojwa support Workers EPG are described in 

Sections 4.2 and 4.3.

4.1.4. Southern Island Workers EPG

This EPG includes personnel whose primary job involved working on one or more of the 

southern islands of the atoll. As described in Section 3, activities of members of this EPG 

included removal, transport, and disposal of uncontaminated debris; building and maintaining 

facilities and structures; and providing support services. In addition, a small volume (110 yd3) of 

soil contaminated with Co-60 was removed from Medren and transported to Runit over a period 

of four days (DNA, 1981). Due to the small soil volume, absence of TRU contamination, and 

short duration, this activity was not a significant potential source of exposure. Typical members 

of this EPG would include, but are not limited to, members of all of the service elements and 

FCDNA that provided support services such as laundry, finance, medical, postal, 

communication, security, airfield, and administrative services. The members of this EPG were 

billeted at the residence facilities on Enewetak Island.

The primary potential sources of external whole-body exposure for members of this EPG

are as follows:

• Fallout mixed in the top layer of soil on the southern islands

• Contaminated equipment

• For skin and the lens of the eye, contaminated soil deposited directly on the skin or clothing.

The primary potential sources of internal exposure and intake routes for members of this 

EPG are as follows: 

• Inhalation of contaminated soil suspended by routine activities such as vehicle traffic

• Ingestion of locally-sourced foods

• Incidental ingestion of contaminated soil and dust 

• Inadvertent ingestion of lagoon or ocean water while extracting offshore debris or swimming.

The exposure scenario used to maximize doses for this EPG is represented by workers 

who participated in construction of houses and other buildings on Medren as part of the 

Enewetak Rehabilitation Program for their entire assignment. This is used as the exposure 

scenario for this EPG because of the higher doses potentially accrued while routinely working on 

Medren as compared to other southern islands. Full workday outdoor exposures on Medren for 

an entire 12-month ECUP assignment is assumed.
24

The maximized external exposures to the whole-body and skin dose for this EPG involve 

exposure to contaminants in the top layer of soil on Medren (work) and Enewetak (residence) 

islands on all work and non-workdays. Maximized daily exposure of skin to dermal 

contamination from Medren soil is also included.

The maximizing internal exposure pathways include inhalation of suspended soil on 

Medren on all workdays, inhalation of suspended soil on Enewetak during all outdoor off-duty 

hours, routine consumption of local food, and incidental ingestion of contaminated soil and dust 

on Enewetak. 

Parameter values used for estimation of external whole-body doses, internal organ doses, 

external skin doses resulting from the sources and pathways described above for the maximizing

scenario of the Southern Island Workers EPG are described in Sections 4.2 and 4.3. 

4.2 External Dose Parameter Values

This section describes the assumptions and parameter values that are used to estimate 

maximized upper-bound external radiation doses for the ECUP EPGs. Common and EPGspecific parameter values are described in the following subsections. Some parameter values are 

defaults, and some are indicated as maximizing values. The equations used for the dose 

estimation are presented in Appendix C of DTRA (2020).

4.2.1. External Dose Parameter Values Common to all ECUP EPGs

Values for several parameters used for calculating the ECUP EPG external doses are the 

same for all four EPGs. These common parameters are shown in Table 5, with a discussion of 

the parameters below. 

• Duration of duty tour: The typical ECUP temporary duty assignment was 4–6 months 

(DNA, 1981). The assignment of some participants was extended to as long as 1 year. 

• Work schedule: The maximum work schedule for all participants was 10 hours for 6 days a 

week. ECUP workers typically did not work on Sundays (DNA, 1981). 

• Travel time: For many workers, the 10-hour workday included up to 2 h of travel time 

between the residence island and the work location. There was no potential for exposure 

during this travel time. Assumption of no travel time is a dose-maximizing assumption.

• Time spent outdoors and indoors: It is assumed that all of a participant’s time during his 

assignment was spent on either a work island or the residence island. To maximize the 

estimated dose, it is assumed that all time on the work island was outdoors. Outdoor time on 

the residence island is assumed to be all time spent on the island except for 8 h d−1 spent 

sleeping indoors every day.

• Building protection factor: This parameter accounts for the degree of protection from 

radiation afforded by the walls and floor of a tent or building. The value assumed for the 

EPGs is a value applicable to a soft-sided tent rather than the metal buildings that were 

typically used for sleeping (DTRA, 2021, SM ED02).
25

Table 5. External dose parameter values common to all ECUP EPGs

Parameter Value Comment

Duration of duty tour 1 y (52 wk) Maximizing value is used instead 

of typical duration of 26 wk

Work schedule on work island 10 h d−1 for 6 d wk−1

Maximizing values are used 

assuming entire workday for all 

workdays spent on work island

Travel time to work island 0 h d−1 Maximizing value is used instead 

of typical 1-2 h d−1 travel time

Time spent outdoors

(1) Workdays: Work Island

Residence Island

(2) Non-workdays: Work Island

Residence Island

10 h d−1

6 h d−1

0

16 h d−1

Maximizing values are used that 

assume all work and non-work 

time is outside except time for 

8 h d−1 sleeping indoors 

Time spent indoors (all days) 8 h d−1 See discussion in text

Building protection factor

Work Island

Residence Island

1.0

1.5

Maximizing value for tent is used 

instead of value of 2.0 applicable 

to metal buildings

Film badge conversion factor 0.7 rem R−1 SM ED02 (DTRA, 2021)

Fraction of time exposed to source 1.0

Maximizing value is used that 

assumes continuous exposure to 

external source during work hours

Uncertainty factor 3 SM UA01 (DTRA, 2021)

• Film badge conversion factor: The film badge conversion factor is the ratio of dose 

recorded on a properly worn film badge to free-in-air integrated exposure and is used to 

convert an exposure to a dose. The factor accounts for body shielding of the film badge to 

gamma radiation and is assigned the values of 0.7 for the standing position on a planar 

surface (DTRA, 2021, SM ED02).

• Fraction of time exposed to source: This factor accounts for the fraction of time that an 

ECUP worker is actually exposed to a specific external source of radiation. Examples of 

scenario characteristics that could be accounted for include fraction of a workday that an 

individual is on a specific island, or is near a specific source (e.g., debris piles). The value of 

1.0 is a maximum value. 

• Uncertainty factor: This factor represents the ratio of an upper-bound dose to the best 

estimate dose. The uncertainty factor is typically used to ensure that an upper-bound dose is 

estimated that has a 95 percent probability of being higher than the actual dose. The use of an 

uncertainty factor with the EPG doses that are already maximized results in a dose above a 

95th percentile dose. 

4.2.2. External Dose Parameter Values Specific to each EPG

For all four EPGs, the only external source assumed for estimating whole body external 

doses is undisturbed contaminated soil. This source has been determined to bound doses from 
26

exposures to other sources of external radiation that ECUP participants in a specific EPG may 

have encountered such as contaminated debris (DTRA, 2020). The specific external exposure 

rates used for each EPG are shown in Table 6, and brief discussions of the exposure rate for each 

EPG follow the table. 

Table 6. External exposure rates for ECUP EPGs

4.2.2.1 Soil Removal Workers EPG

The external exposure rate on the work island used for this EPG consists of the weighted 

average of the island-average exposure rates on the five soil removal islands, i.e., Boken, Enjebi, 

Lujor, Aomon, and Runit. The weighted average is calculated by weighting each of the five 

island exposure rates by the fraction of the total volume of excised soil that is removed from the 

island and assumes that the volume of soil removed is directly related to time spent on the island. 

The residence island external exposure rate used for this EPG is the island-average exposure rate 

for Lojwa. Although the residence facilities on Lojwa were not available for the entire 1977–

1980 period, they were used for greater than a 1-y period. (DTRA, 2020)

4.2.2.2 Northern Island Workers EPG

The external exposure rate on the work island used for this EPG consists of the weighted 

average of the island-average exposure rates on the northern islands. The weighted average is 

calculated by weighting each island exposure rate by the fraction of the total volume of debris 

that was removed from the island and assumes that the volume of debris removed is directly 

related to time spent on the island by workers in this EPG. The residence island external 

exposure rate used for this EPG is the island-average exposure rate on Lojwa. Although the 

residence facilities on Lojwa were not available for the entire 1977–1980 period, they were used 

for more than one year. (DTRA, 2020)

4.2.2.3 Lojwa Support Workers EPG

The work and residence island external exposure rate used for this EPG is the islandaverage exposure rate on Lojwa (DTRA, 2020).

Parameter Soil Removal

Workers

Northern Island 

Workers

Lojwa Support 

Workers

Southern Island 

Workers

External exposure rate* (μR h−1)

Work Island

Residence Island

39†

5

36†

5

5

5

0.31

0.26

* The exposure rates used in the EPG dose assessments are not decay-corrected for the elapsed time from the 

AEC 1972-1973 surveys to the time of the ECUP exposure scenarios.

† These exposure rates are weighted averages and are used to account for the assumed amount of time on each of 

the islands relevant to the EPG. See Sections 4.2.2.1 and 4.2.2.2 for additional information.
27

4.2.2.4 Southern Island Workers EPG

The external exposure rate on the work island for this EPG consists of the island-average 

exposure rate on Medren. Although the island-average external exposure rate on Medren was 

lower than several other southern islands, this work location is used because there was a 

considerable amount of work accomplished on the island such as debris removal and 

rehabilitation work. Furthermore, the soil TRU concentrations were higher on Medren than on all 

other southern islands except Biken, a small, isolated island with a small volume of noncontaminated debris that was removed. The residence island external exposure rate used for this 

EPG is the island-average exposure rate of Enewetak Island. (DNA, 1981; DTRA, 2020)

4.3 Internal Dose Parameter Values

This section describes the assumptions and parameter values that are used to estimate 

maximized upper-bound internal radiation doses for the ECUP EPGs. Common and EPGspecific are described in the following subsections. Some parameter values are defaults, and 

some are indicated as maximizing values. The equations used for the dose estimation are 

presented in Appendix C of DTRA (2020).

4.3.1. Internal Dose Parameter Values Common to all ECUP EPGs

Values for several parameters used for calculating the ECUP EPG internal doses are the 

same for all four EPGs. These common parameter values are shown in Table 7. Parameters for 

duration of duty tour, Work schedule, Travel time to Work Island, Time spent outdoors, and 

Time spent indoors are discussed in Section 4.2.1 and are not repeated here. The remaining 

parameters are discussed below. 

• Soil density: A default value of 1.5 g cm−3 is used based on the recommendation in DTRA 

(2020) and SM ID01 (DTRA, 2021).

• Depth of soil available for suspension: A default value of 1 cm is used based on the 

recommendation in DTRA (2020) and SM ID01 (DTRA, 2021). 

• Breathing rate: A default breathing rate of 1.2 m3 h−1 is based on an adult male performing 

light activities, comparable to walking at a rate of 3 mph on a flat firm surface (DTRA, 2021, 

SM ID01). This rate is used as an average, constant breathing rate for all periods and 

activities where inhalation exposure is applied. 

• Respiratory protection factor: This factor represents the degree of protection afforded by a 

respirator, and it is equal to the ratio of the concentration of contaminants outside the 

respirator to the concentration inhaled. Although respiratory protection with protection 

factors up to 1,000 was required during certain activities, some ECUP veterans have stated 

that they did not wear respiratory protection at any time. Therefore, a value of 1 is assumed 

in order to maximize the inhalation dose estimates. 

• Fraction of time exposed to source: This factor is intended to account for the fraction of a 

workday or workweek that an ECUP worker is actually exposed to suspended soil. Examples 

of scenario characteristics that could be accounted for include fraction of a workday that 

disruption of soil is actually occurring, and the locations of personnel with respect to the 

prevailing wind. A value of 1.0 for this parameter is a maximum value. 
28

Table 7. Internal dose parameter values common to all ECUP EPGs

Parameter Value Comment

Duration of duty tour 52 wk Maximizing value is used instead of 

typical duration of 26 wk

Work schedule

10 h d−1

for

6 d wk−1

Maximizing values are used assuming 

entire workday for all workdays spent 

on work island

Travel time to work island 0 h Maximizing value is used instead of 

typical 1-2 h d−1 travel time

Time spent outdoors

Workdays: Work Island

Residence Island

Non-workdays: Work Island

Residence Island

10 h d−1

6 h d−1

0

16 h/d

Maximizing values are used that 

assume all work and non-work time is 

outside except 8 h d−1 sleeping indoors 

Time spent indoors (all days) 8 h d−1 See discussion in text

Soil density 1.5 g cm−3 See discussion in text

Suspended soil thickness 1 cm See discussion in text

Inhalation rate 1.2 m3 h−1 SM ID01 (DTRA, 2021)

Respiratory protection factor

Work Island

Residence Island

1

1

Maximizing values are used that 

assume no respiratory protection used 

at any time, instead of factor of 50–

1,000 for respirators required during 

soil handling operations

Fraction of outdoor time 

exposed to airborne source

1.0

Maximizing value is used that 

assumes continuous exposure to 

suspended soil during work hours

Consumption of local food

Fish

Clam

Coconut Meat

Coconut Crab

 4 servings mo−1

1 serving mo−1

1 serving mo−1

1 serving mo−1

Maximizing values assume that a

veteran consumed all four foods at the 

indicated rates

Incidental ingestion of 

contaminated soil and dust

0.002 rem

(all organs)

Maximized dose is assigned instead of 

calculated organ doses less than 

0.002 rem for most organs

Inhalation Dose Coefficients Organ-specific

(Table A-1) See discussion in text

Ingestion Dose Coefficients Organ-specific

(Table A-2) See discussion in text

Uncertainty factor 10 SM UA01 (DTRA, 2021)

• Consumption of local food: The default assumption for most ECUP dose assessments is that 

local foods were not consumed. However, some ECUP veterans have stated that they 

occasionally ate certain local foods. Fish is the most likely local food that might have been 
29

consumed by ECUP participants, and other accessible foods may also have been collected 

and eaten. In order to reasonably maximize this potential exposure pathway, very high-sided 

consumption rates of four local foods are used. Organ doses per serving for each type of local 

food have been estimated (DTRA, 2020). 

• Incidental ingestion of soil and dust: This exposure pathway is normally assessed for ECUP 

participants using a default incidental soil and dust ingestion rate of 0.05 g d−1 to calculate an 

upper-bound dose in SM ID01 (DTRA, 2021). However, previous ECUP dose estimates have 

demonstrated that the highest organ dose for this pathway for a 1-year exposure is 

approximately 0.002 rem for bone surface. Therefore, in order to simplify this exposure 

pathway, a dose of 0.002 rem is assigned for all organs and all EPGs and the internal dose 

uncertainty factor of 10 is applied.

• Inhalation dose coefficients: To high side the dose estimates for most internal organs, it was

assumed that all suspended soil particles were respirable with an average activity median

aerodynamic diameter (AMAD) of 1 μm. This conservative assumption results in dose

coefficients that are higher than those of AMADs in the 3–10 μm range by factors of up to

about 4 for most organs.

In addition to particle size, the chemical form of a radionuclide affects the doses delivered to

internal organs. The five radionuclides of most importance for inhalation doses to ECUP

participants are the fission products Sr-90 and Cs-137, the TRU radionuclides Pu-239 and

Am-241, and the neutron activation product Co-60 (DTRA, 2020). Although Cs-137 and

Am-241 each has only one set of dose coefficients available for all chemical forms, dose

coefficients are available for multiple chemical forms for Sr-90, Pu-239, and Co-60. However, 

a definitive understanding of the chemical forms of these radionuclides in the environment at 

Enewetak Atoll during the ECUP is not available. Therefore, the ICRP 68 category 

“unspecified compounds” with the corresponding material type absorption rate was assumed 

for Sr-90, Pu-239, and Co-60. Material types assumed for all five radionuclides are given in 

Appendix A.

The choice of “unspecified compounds” results in higher dose coefficients by factors of up to

20 for Sr-90 and Pu-239 for most organs. Lungs are an exception to this generalization, as the

Pu-239 dose coefficient for lung corresponding to insoluble oxides is higher than the

unspecified compounds dose coefficient by a factor of about 2.5 due to a lower lung clearance 

value. In addition, Co-60 dose coefficients for “unspecified compounds” are generally lower 

than those for specific compounds by a factor of up to 4. However, for the most important 

radionuclides of concern for estimated internal doses, e.g., Pu-239 and

Am-241, these assumptions high side the organ doses by at least a factor of 8. (ICRP, 2011)

• Ingestion dose coefficients: Like the inhalation dose coefficients discussed above, when a

choice was available in determining the dose coefficients (for Sr-90, Pu-239, and Co-60),

“Unspecified compounds” was assumed. For all organs, this assumption results in the use of

very similar or higher dose coefficients than those for alternative choices by factors of up to

30 for Sr-90 and up to 50 for Pu-239. Ingestion dose coefficients for Co-60 do not vary much

for different chemical forms. (ICRP, 2011) 
30

4.3.2. Internal Dose Parameter Values Specific to each EPG

The only EPG-specific internal exposure pathway is inhalation of suspended soil. The 

specific parameter values used for each EPG for estimation of soil inhalation doses from this 

pathway are shown in Table 8, and brief discussions of the parameter values for each EPG are in 

the following subsections. 

4.3.2.1 Soil Removal Workers EPG

The soil radionuclide concentrations on the work island used for this EPG for all 

radionuclides except TRU radionuclides consist of the weighted averages of the island-average 

concentrations on the five soil removal islands of Boken, Enjebi, Lujor, Aomon, and Runit. The 

weighted average is calculated by weighting each of the island concentrations by the fraction of 

the total volume of excised soil that is removed from the island and assumes that the volume of 

soil removed is directly related to time spent on the island. To maximize the potential internal 

dose, the value listed for Pu-239 in Table 8 is the weighted average of TRU radioactivity 

concentration in soil removed from the soil removal islands. The TRU value is weighted in the 

same manner as the other radionuclides. Small quantities of TRU radionuclides other than 

Pu-239 were also present in excised soil and elsewhere on the atoll (e.g., Pu-238 and Pu-241) as 

well as other fission products (e.g., Sb-125 and Eu-155). However, because of their low 

concentrations and/or radiological decay characteristics, these additional radionuclides are not 

important from an ECUP radiological dose perspective. The residence island soil concentrations 

used for this EPG are the island-average concentrations on Lojwa. (DTRA, 2020)

The resuspension factor used for the work island for this EPG is based on airborne soil 

concentrations near an operating bulldozer and is applicable to soil excision and windrowing

activities. The selected value for the resuspension factor for this EPG is 1.2 × 10−7 m−1, which 

corresponds to a mass loading of 600 μg m−3 (DTRA, 2020). An additional maximizing 

assumption is that dust suppression during soil disruption activities via water spraying is not 

considered. The resuspension factor used for the residence island of Lojwa for this EPG is based 

on the default mass loading value reported in DTRA (2020) and is representative of airborne 

mass loading due to truck traffic. The selected value for the resuspension factor for this EPG 

residence island is 2 × 10−8 m−1, which corresponds to a mass loading of 100 μg m−3 (DTRA, 

2020). This high-sided value is approximately 2.5 times greater than the estimated ambient dust 

loading of 40 μg m−3 for the Atoll (AEC, 1973). A discussion of ECUP mass loading values and 

conversions between mass loading values and resuspension factors is provided in DTRA (2020). 
31

Table 8. EPG-specific inhalation dose parameter values

Parameter Soil Removal

Workers*

Northern 

Island 

Workers*

Lojwa 

Support 

Workers

Southern 

Island 

Workers

Soil radionuclide concentrations on work island(s) (pCi g−1) †

Sr-90

Cs-137

Pu-239

Am-241

Co-60

47.2

17.1

123‡

-

§

3.1

39.4

13.9

12.8

3.28

1.70

8.2

2.6

1.8

1.2

0.31

0.76

0.32

0.21

0.14

0.06

Soil radionuclide concentrations on residence island (pCi g−1) †

Sr-90

Cs-137

Pu-239

Am-241

Co-60

8.2

2.6

1.8

1.2

0.31

8.2

2.6

1.8

1.2

0.31

8.2

2.6

1.8

1.2

0.31

0.61

0.25

0.08

0.05

0.04

Resuspension factor (m−1)

Work Island(s)

Residence Island

1.2 10−7 

2.0 10−8

6.0 10−8

2.0 10−8

2.0 10−8

2.0 10−8

2.0 10−8

2.0 10−8

* The soil radionuclide concentrations on the work islands for these EPGs are weighted averages and are used to 

account for the assumed amount of time on each of the islands relevant to the EPG. See Sections 4.3.2.1 and 

4.3.2.2 for additional information.

† These soil radionuclide concentrations are not decay-corrected for the elapsed time between the AEC 1972-

1973 surveys and the start of the ECUP.

‡ This is the estimated average TRU concentration of the soil removed from the five soil removal islands (DTRA, 

2020).

§ Am-241 is included in the value shown for Pu-239. 

4.3.2.2 Northern Island Workers EPG

The soil radionuclide concentrations on the work island used for this EPG consists of the 

weighted average of the island-average exposure rates on the northern islands. The weighted 

average is calculated by weighting each of the island concentrations by the fraction of the total 

volume of debris removed from the island and assumes that the volume of debris removed is 

directly related to time spent on the island by workers in this EPG. The residence island soil 

concentrations used for this EPG are the island-average concentrations on Lojwa. (DTRA, 2020)

The resuspension factor used for the work island for this EPG is based on airborne soil 

concentrations near activities such as agricultural tilling. It is considered to be applicable to 

vegetation clearing, buried debris removal, and similar ECUP activities. The selected value for 

the resuspension factor for work islands for this EPG is 6 × 10−8 m−1, which corresponds to a 

mass loading of 300 μg m−3 (DTRA, 2020). An additional maximizing assumption is that dust 

suppression during any soil disruption activities via water spraying is not considered. The 

resuspension factor used for the residence island of Lojwa for this EPG is based on the default 

mass loading value reported in DTRA (2020) and is representative of airborne mass loadings due 
32

to truck traffic. The selected value for the resuspension factor for this EPG residence island is 

2 × 10−8 m−1, which corresponds to a mass loading of 100 μg m−3 (DTRA, 2020). Like the Soil 

Removal Workers EPG described in Section 4.3.2.1, the high-sided default value is 

approximately 2.5 times greater than the estimated ambient dust loading for the Atoll. (AEC, 

1973; DTRA, 2020) 

4.3.2.3 Lojwa Support Workers EPG

The soil radionuclide concentrations on the work and residence island used for this EPG 

(Lojwa) are the island-average concentrations on Lojwa (DTRA, 2020).

The resuspension factor used for the work and residence island of Lojwa for this EPG is 

based on the default mass soil loading value reported in DTRA (2020) and is representative of 

airborne mass loadings due to truck traffic. The selected value for this resuspension factor is 

2 × 10−8 m−1, which corresponds to a mass loading of 100 μg m−3 (DTRA, 2020). Like the Soil 

Removal Workers EPG described in Section 4.3.2.1, the high-sided default value is 

approximately 2.5 times greater than the estimated ambient dust loading for the Atoll. (AEC, 

1973; DTRA, 2020) 

4.3.2.4 Southern Island Workers EPG

The soil radionuclide concentrations on the work island used for this EPG consist of the 

island-average concentrations on Medren. This work location is used because there was a 

considerable amount of work accomplished on the island (debris removal and rehabilitation 

work) and the soil TRU concentration is higher than on all other southern islands except Biken, a 

small, isolated island with a small volume of non-contaminated debris that was removed. The 

residence island soil radionuclide concentrations used for this EPG is the island-average 

concentrations on Enewetak, which was the primary residence island for ECUP. (DTRA, 2020)

The resuspension factor on the work and residence islands used for this EPG, Medren and 

Enewetak, respectively, is based on the default mass loading value reported in DTRA (2020) and 

is representative of airborne mass loadings due to truck traffic. The selected value for this

resuspension factor is 2 × 10−8 m−1, which corresponds to a mass loading of 100 μg m−3 (DTRA, 

2020). Like the other EPGs, this high-sided default value is approximately 2.5 times greater than 

the estimated ambient dust loading for the Atoll. (AEC, 1973; DTRA, 2020) 

4.4 Skin Dose Parameter Values

This section describes the assumptions and parameter values that are used to estimate 

maximized upper-bound skin doses for the ECUP EPGs. The skin dose estimation consists of an 

external non-contact dose from contaminated soil, and an external dose due to contamination 

deposited on the skin. Dose parameters used for these two exposure pathways are discussed in 

the following subsections. The equations used for the dose estimation are presented in 

Appendix C of DTRA (2020).
33

4.4.1. Parameter Values for Non-contact Skin Doses

Non-contact skin doses consist of external exposure of the skin to gamma and beta 

radiation emanating from a contaminated source. For the ECUP EPG skin dose assessments, the 

contaminated source consists of undisturbed soil on the work and residence island(s). Because 

this is an external exposure dose that would be accrued simultaneously with the external wholebody dose discussed in Section 4.2, the parameters and maximizing parameter values are largely 

the same as discussed in that section. Specifically, the parameters in Table 5 and Table 6 are 

used for the estimation of non-contact skin doses. In addition to these parameters, other 

assumptions include a veteran height of 68 inches, and a modifying factor of 1 to estimate 

exposure of bare skin. The final parameter used in the estimation of non-contact skin doses is the 

beta-gamma dose ratio. The beta-gamma dose ratios used for 17 skin sites on an individual of 

height 173 cm (68 in) are shown in Table 9 (DTRA, 2020). These parameters are briefly 

discussed below.

• Veteran height: A veteran height of 68 inches is assumed. This value is typically assumed 

as a default value in NTPR, and it is similar to the ICRP reference value of 176 cm (69.3 in) 

for adult males (ICRP, 2002). An assumed height that is less than the reference height results

in slightly higher non-contact skin doses for most skin sites. 

• Modifying factor: A value of 1 is used, which indicates no modifications to the dose 

estimates to account for factors such as a skin site covered by clothing. A factor of 1.0 

represents exposure to bare, dry skin, and is used for all veteran skin sites in order to 

maximize the estimated non-contact skin doses. 

• Beta-gamma dose ratio: The beta-gamma dose ratio relates the beta skin dose to the 

gamma skin dose from exposure to a contaminated infinite plane source. Values of this ratio 

for ECUP scenarios have been estimated (DTRA, 2020). Median values of these ratios are 

used for all ECUP EPGs.
34

Table 9. Skin site-specific parameter values

Skin Site

Skin Site Height 

Above Ground 

(standing) (cm)*

Beta-Gamma 

Dose Ratio*

Skin Dose 

Modification 

Factor†

Effective 

Retention 

Fraction†

Scalp 173 0.177 1.3 0.23

Face 160 0.194 1.3 0.015

Forehead 160 0.194 1.3 0.015

Behind ear 160 0.194 1.3 1.5

Neck 150 0.207 1.3 0.015

Back of neck 150 0.207 0.9 1.5

Shoulder 140 0.222 1.3 0.015

Chest 140 0.222 1.3 0.03

Torso (back, side) 140 0.222 1.3 0.015

Under belt 119 0.256 1.3 1.5

Forearm 99 0.295 0.9 0.06

Upper leg 71 0.366 1.3 0.06

Palm 71 0.366 0.3 0.015

Back of hand 71 0.366 1.3 0.06

Lower leg 20 0.631 0.9 0.06

Sole of foot 1 1.270 0.3 0.06

Under boot edge 1 1.270 0.9 1.5

* Skin site heights and beta-gamma dose ratios are for an individual with a height of 173 cm (68 in).

† The Skin Dose Modification Factor and the Effective Retention Fraction are used in the dermal contamination 

skin dose estimation (DTRA, 2021, SM ED04).

4.4.2. Parameter Values for Dermal Contamination Skin Doses

Dermal contamination skin doses consist of external exposure of the skin to gamma, beta, 

and alpha radiation emanating from a contaminated source deposited on the skin or clothing. For 

the ECUP EPG skin dose assessments, the contaminated source consists of contaminated soil on 

the work and residence island(s) that has been suspended and then deposited on the skin. 

Because this is an external exposure dose that would be accrued simultaneously with the internal 

doses from suspended soil discussed in Section 4.3, there are many parameters and parameter 

values in common with those discussed in that section. Specifically, the parameters in Table 7

and Table 8 regarding maximizing assignment duration and work schedule, time spent indoors 

and outdoors, as well as resuspension factors, soil density, suspended soil thickness, and 

radionuclide concentrations, are used for the estimation of dermal contamination skin doses. 

Skin-site specific parameters used to estimate dermal contamination skin doses are shown in 

Table 9 (skin dose modification factors and effective retention fractions). Additional parameters 

include an airborne soil deposition velocity of 1 m s−1

, an additional post-work exposure time of 

2 h, and a maximizing value of 1.0 for the fraction of a workday a worker is exposed to 

suspended soil. Finally, radionuclide- and skin site-specific dose coefficients for dermal 

contamination are shown in Table 10. (DTRA, 2020) 
35

Table 10. Dermal contamination skin dose coefficients

Dose Coefficient (rem h−1 per pCi cm−2)

*

Skin site Sr/Y-90 Cs-137 Pu-239/240 Am-241 Co-60

Scalp 1.20 10−5 5.69 10−6 6.40 10−3 7.40 10−3 3.83 10−6

Face (all sites) (all sites) 6.40 10−3 7.40 10−3 (all sites)

Forehead 6.40 10−3 7.40 10−3

Behind ear 6.40 10−3 7.40 10−3

Neck 6.40 10−3 7.40 10−3

Back of neck 6.40 10−3 7.40 10−3

Shoulder 6.40 10−3 7.40 10−3

Chest 6.70 10−3 8.20 10−3

Torso (back, side) 6.40 10−3 7.40 10−3

Under belt 6.70 10−3 8.20 10−3

Forearm 7.40 10−4 1.30 10−3

Upper leg 7.40 10−4 1.30 10−3

Palm 0 0

Back of hand 0 0

Lower leg 7.40 10−4 1.30 10−3

Sole of foot 0 0

Under boot edge 7.40 10−4 1.30 10−3

* Dermal contamination dose coefficients are documented in DTRA (2020). If a value is not included in that 

report for a specific skin site, an estimated value is used.

Maximized skin doses from dermal contamination are estimated over a total period of 

12 h d−1 for all EPGs. This is based on the maximizing assumption that the total amount of 

contaminated soil that could have gradually accumulated on bare skin over a 10-hour workday is

assumed to be deposited at the beginning of the workday. Furthermore, accumulated soil is 

assumed to remain on the skin until completely removed by washing an average of 2 h after the 

end of the workday. Daily soil accumulation on the skin is limited to 2 mg cm−2 because it is 

likely that a worker would brush off accumulated soil before such an amount is deposited 

(DTRA, 2020). The assumption that the entire amount of soil that would have accumulated 

during the workday is deposited at the beginning of the day overestimates the skin dermal 

contamination dose by a factor of about two. The assumptions of a 10-hour accumulation period 

and 12-hour dose period for workdays are also used for non-workdays. Ignoring the small skin 

dermal contamination doses from any accumulation while outdoor on the residence island 

following the workday is largely compensated by the assumption of deposition of the daily soil 

loading at the beginning of the day. In addition, the radionuclide soil concentrations on the 

residence islands were lower than on work islands and there were fewer activities conducted 

during non-work hours that would disrupt soil. 
36

4.5 Lens of Eye Dose Parameter Values

A dose to the lens of the eye is estimated for the ECUP EPGs for use in veteran claims 

involving posterior subcapsular cataracts (“cataracts”). In order to simplify the EPG assessments, 

a single, maximized upper bound is estimated that bounds the potential dose for ECUP 

participants in all ECUP EPGs. The dose estimation for the lens of the eye consists of a

maximized upper-bound external non-contact dose from contaminated soil, and a maximized

upper-bound external dose due to contamination deposited on the eyelid. Dose parameters used 

for these two exposure pathways are discussed in the following subsections. 

4.5.1. Parameter Values for Non-contact Lens of Eye Dose

Similar to the ECUP EPG skin dose, the source and exposure pathway for the noncontact dose to the lens of the eye consists of external exposure to gamma and beta radiation 

emanating from undisturbed soil on the work and residence island(s). Because this is an external 

exposure dose that would be accrued simultaneously with the external whole body dose and the 

skin doses discussed in Sections 4.2 and 4.4, some of the parameters and parameter values are 

the same as discussed in those sections. Specifically, the parameter values in Table 5 and the 

external exposure rate for the Soil Removal Workers EPG in Table 6 are used for the estimation 

of the gamma portion of the non-contact skin doses. As a maximizing assumption, this dose is 

estimated for a height corresponding to an individual that is sitting on the ground for an entire 

ECUP assignment. Additional parameters used to estimate the beta portion of the non-contact 

dose are shown in Table 11.

Table 11. Parameter values used to estimate the non-contact lens of the eye dose

Parameter Value Comment

Height of eye while sitting on the 

ground 75 cm

Maximizing assumption used 

instead of standing eye height of 

160 cm

Ratio of lens of the eye betagamma dose ratio to eyelid betagamma dose ratio

0.25

Estimated value based on available 

ratios for NTPR (see text 

discussion)

Beta-gamma dose ratio for skin of 

eyelid while sitting on the ground 0.354 Median value estimated using method in DTRA (2020) 

Beta-gamma dose ratio for lens of 

the eye while sitting on the ground 0.089 Calculated using parameter values listed above

• Height of eye: This maximizing assumption assumes that a participant is sitting on the 

ground rather than standing upright. This orientation places the lens of the eye at 75 cm 

above the contaminated ground source rather than the default height of 160 cm. This 

increases the estimated beta radiation dose. 

• Ratio of lens of the eye beta-gamma dose ratio to eyelid beta-gamma dose ratio: Betagamma dose ratios for the lens of the eye are not available for ECUP scenarios. Therefore, a 

value is estimated for ECUP based on the NTPR lens of the eye beta-gamma dose ratios in 
37

SM ED05 (DTRA, 2021), and the beta-gamma dose ratios for bare skin exposures in 

SM ED03 (DTRA, 2021).

• Beta-gamma dose ratio for skin of eyelid: The beta-gamma dose ratio for the eyelid is 

based on the ratio for the skin of the face. This ratio relates the beta skin dose to the gamma 

skin dose from exposure to a contaminated infinite plane source. A median value of this ratio 

for a height of 75 cm was estimated using the equation provided in DTRA (2020). 

4.5.2. Parameter Values for Lens of the Eye Dose from Dermal Contamination of Eyelid

The lens of the eye dose from dermal contamination of the eyelid consists of external 

exposure of the lens of the eye to gamma and beta radiation emanating from contaminated soil 

deposited on the eyelid. For this dose assessment, the contaminated soil is assumed to be 

suspended and then deposited on the eyelid while on the work and residence islands. The dose is 

based on the dermal contamination beta dose to the eyelid, and application of a ratio of the lens 

of the eye dose to the eyelid dose. Because this is an external exposure dose that would be 

accrued simultaneously with the external and skin dermal contamination doses from suspended 

soil, there are many parameters and parameter values in common with those discussed in 

Sections 4.2 and 4.4.2. Specifically, the maximizing parameter values in Table 7 and Table 8

regarding assignment duration and work schedule, time spent indoors and outdoors, as well as 

the resuspension factors, soil density, suspended soil thickness, and radionuclide concentrations 

for the Soil Removal Workers EPG are used for the estimation of dermal contamination skin 

doses. Additional parameters used to estimate the lens of the eye dose are shown in Table 12.

Table 12. Parameter values used to estimate the lens of the eye dose

from dermal contamination of the eyelid

Parameter Value Comment

Upper-bound dermal contamination 

beta+gamma eyelid dose (rem) 0.003 See Section 4.4.2. (dose to face is used as a surrogate)

Ratio of 95th percentile to default 

values of Effective Retention 

Fraction for face

8

Maximizing value based on the NTPR 

95th percentile upper limit of this 

parameter rather than the NTPR default 

value in SM ED04 (DTRA, 2021)

Ratio of lens of the eye dose to 

eyelid dose

0.2 NTPR methodology in SM ED05

(DTRA, 2021)
38

5.

Results and Discussion of the ECUP Expedited Processing Doses

Four EPGs with distinct exposure scenarios are identified in Section 3 that collectively 

cover the majority of the ECUP participants. The details of the dose assessments for the four 

EPGs are presented in Section 4. This section presents the external and internal organ doses, and 

external skin doses estimated for each EPG. A bounding dose to the lens of the eye applicable to 

all EPGs is also discussed. Recommendations for use of the dose results in expedited processing, 

including EPG/organ combinations not recommended for expedited processing, are also 

discussed. 

5.1 Dose Assessment Results

Scenario-based external, internal, skin, and lens of the eye doses are calculated for each 

EPG based on the methodology described in Section 4. These doses and their corresponding 

upper bounds are recommended for use in expedited processing of most ECUP cases except as 

noted in this section.

5.1.1. External and Internal Organ Doses

The EPG doses consist of estimates calculated using maximizing exposure scenarios and 

input parameter values that clearly high side each dose component. The EPG doses are estimated 

for external gamma radiation, internal alpha radiation, and internal beta+gamma radiation for 24

organs, for which ICRP 68 dose coefficients are available. The 24 EPG TODs are calculated for 

each EPG by adding the upper-bound external dose and the upper-bound internal alpha and 

beta+gamma organ doses. 

For each EPG, upper-bound doses are generated from the maximized doses by applying 

DTRA-approved uncertainty factors, which are detailed in SM UA01 (DTRA, 2021). Across all 

EPGs, the maximized upper-bound external doses range from less than 0.1 to 0.3 rem. A wider 

range is observed for maximized upper-bound internal organ doses. The maximized external 

doses, the maximized upper-bound external and internal doses (upper-bound alpha and 

beta+gamma doses presented separately), and the EPG TODs for four ECUP EPGs are provided 

in Table 13.

5.1.2. Skin Doses

Maximized upper-bound skin doses (alpha, beta+gamma, and total) are calculated for 

17 representative skin sites for members of the four EPGs using the assumptions and parameter 

values described in Section 4. A summary of these skin doses is shown in Table 14. 
39

Table 13. Estimated organ doses for ECUP EPGs (rem) *

EPG Name

Internal 

Radiation

Type

and 

EPG TOD*

ECUP Standard Organs

AdrenalsBladder WallBone SurfaceBrainBreastEsophagusStomach WallSI Wall*ULI Wall*LLI Wall*ColonKidneysLiverMuscleOvariesPancreasRed MarrowET Airways*LungsSpleenTestesThymusThyroidUterus

Soil Removal 

Workers UB α 0.08 0.08 47 0.08 0.08 0.08 0.08 0.08 0.09 0.09 0.09 0.2 10 0.08 0.6 0.08 3 0.3 1 0.08 0.6 0.08 0.08 0.08

External

Dose

Upper 

Bound UB β+γ 0.02 0.02 0.07 0.02 0.02 0.02 0.02 0.02 0.02 0.03 0.03 0.02 0.02 0.02 0.02 0.02 0.04 0.02 0.02 0.02 0.02 0.02 0.02 0.02

0.1 0.3 EPG TOD 0.4 0.4 48 0.4 0.4 0.4 0.4 0.4 0.4 0.5 0.4 0.5 10 0.4 1 0.4 3 0.7 2 0.4 1 0.4 0.4 0.4

Northern Island 

Workers UB α 0.009 0.009 4 0.009 0.009 0.009 0.009 0.009 0.01 0.02 0.01 0.02 0.7 0.009 0.06 0.009 0.2 0.03 0.07 0.009 0.06 0.009 0.009 0.009

External

Dose

Upper 

Bound UB β+γ 0.02 0.02 0.07 0.02 0.02 0.02 0.02 0.02 0.02 0.03 0.03 0.02 0.02 0.02 0.02 0.02 0.04 0.02 0.02 0.02 0.02 0.02 0.02 0.02

0.1 0.3 EPG TOD 0.4 0.4 5 0.4 0.4 0.4 0.4 0.4 0.4 0.4 0.4 0.4 1 0.4 0.4 0.4 0.5 0.4 0.4 0.4 0.4 0.4 0.4 0.4

Lojwa Support 

Workers UB α 0.004 0.004 1 0.004 0.004 0.004 0.004 0.004 0.005 0.008 0.006 0.006 0.2 0.004 0.02 0.004 0.05 0.006 0.01 0.004 0.02 0.004 0.004 0.004

External

Dose

Upper 

Bound UB β+γ 0.02 0.02 0.07 0.02 0.02 0.02 0.02 0.02 0.02 0.03 0.03 0.02 0.02 0.02 0.02 0.02 0.04 0.02 0.02 0.02 0.02 0.02 0.02 0.02

0.03 0.09 EPG TOD 0.1 0.1 1 0.1 0.1 0.1 0.1 0.1 0.1 0.2 0.1 0.1 0.3 0.1 0.2 0.1 0.2 0.1 0.1 0.1 0.1 0.1 0.1 0.1

Southern Island 

Workers UB α 0.003 0.003 0.6 0.003 0.003 0.003 0.003 0.004 0.005 0.007 0.006 0.005 0.1 0.003 0.01 0.003 0.03 0.004 0.004 0.003 0.01 0.003 0.003 0.003

External

Dose

Upper 

Bound UB β+γ 0.02 0.02 0.07 0.02 0.02 0.02 0.02 0.02 0.02 0.03 0.03 0.02 0.02 0.02 0.02 0.02 0.04 0.02 0.02 0.02 0.02 0.02 0.02 0.02

0.002 0.005 EPG TOD 0.03 0.03 0.7 0.02 0.02 0.03 0.03 0.03 0.03 0.04 0.04 0.03 0.2 0.02 0.04 0.03 0.07 0.03 0.03 0.03 0.03 0.03 0.03 0.03

* The upper-bound external, UB α, and UB β+γ doses in this table are recommended for assignment in expediting ECUP cases except as noted in Table 15. For each standard organ, the doses 

are recommended for all organs, diseases, and tissues for which the standard organ is applicable. 

† ECUP standard organs are the organs for which internal dose coefficients are available in ICRP 68 (ICRP, 2011).

‡ EPG TOD is the sum of the External Upper Bound, UBα, and UB β+γ doses.

SI = small intestine; ULI = upper large intestine; LLI = lower large intestine; ET Airways = extra-thoracic airways.
40

Table 14. Upper-bound external lens of the eye and skin doses for ECUP EPGs

Dose location

Total Upper-Bound External (beta+gamma) Eye Lens Dose (rem)*

Soil Removal Northern Islands Lojwa Support Southern Islands

Lens of the eye 0.4

Skin Site

Upper-Bound External Skin Doses (rem)

Soil Removal Northern Islands Lojwa Support Southern Islands

UB α UB β+γ UB Tot† UB α UB β+γ UB Tot UB α UB β+γ UB Tot UB α UB β+γ UB Tot

Scalp 45 0.4 45 3 0.4 4 0.3 0.1 0.4 0.02 0.006 0.02

Face 3 0.4 4 0.2 0.4 0.6 0.02 0.1 0.1 0.001 0.006 0.007

Forehead 3 0.4 4 0.2 0.4 0.6 0.02 0.1 0.1 0.001 0.006 0.007

Behind ear 60. 0.5 60. 9 0.4 9 2 0.2 2 0.1 0.007 0.1

Neck 3 0.4 4 0.2 0.4 0.6 0.02 0.1 0.1 0.001 0.006 0.007

Back of neck 60 0.5 60 9 0.4 9 2 0.1 2 0.1 0.006 0.1

Shoulder 3 0.4 4 0.2 0.4 0.6 0.02 0.1 0.1 0.001 0.006 0.007

Chest 6 0.4 7 0.5 0.4 0.8 0.04 0.1 0.2 0.002 0.006 0.008

Torso (backside) 3 0.4 4 0.2 0.4 0.6 0.02 0.1 0.1 0.001 0.006 0.007

Under belt 63 0.5 63 9 0.4 9 2 0.2 2 0.1 0.007 0.1

Forearm 2 0.4 2 0.1 0.4 0.5 0.009 0.1 0.1 <0.001 0.006 0.007

Upper leg 2 0.5 2 0.1 0.4 0.5 0.009 0.1 0.2 <0.001 0.006 0.007

Palm 0 0.4 0.4 0 0.4 0.4 0 0.1 0.1 0 0.006 0.006

Back of hand 0 0.5 0.5 0 0.4 0.4 0 0.1 0.1 0 0.006 0.006

Lower leg 2 0.5 2 0.1 0.5 0.6 0.009 0.2 0.2 <0.001 0.007 0.008

Sole of foot 0 0.7 0.7 0 0.7 0.7 0 0.2 0.2 0 0.009 0.009

Under boot edge 7 0.8 8 1 0.7 2 0.2 0.2 0.4 0.02 0.01 0.03

* A maximized upper-bound lens of the eye dose was estimated for the Soil Removal Workers EPG and is recommended as a bounding dose for all EPGs.

† “UB Tot” is the total upper-bound skin site dose. This dose may not equal the sum of UB α and UB β+γ because the doses shown are rounded up.
41

5.1.3. Lens of the Eye Dose

A maximized external dose for the lens of the eye is estimated for the Soil Removal 

Workers EPG using the assumptions and parameter values described in Section 4. The resulting 

total upper-bound external dose (beta plus gamma) to the lens of the eye is 0.4 rem. The total 

upper-bound skin dose for face for the Soil Removal Workers EPG bounds the upper-bound face 

skin doses for the other three EPGs (Table 14). Therefore, the total maximized upper-bound dose 

to the lens of the eye calculated based on this EPG will bound the lens of the eye doses for the 

other EPGs. This maximized upper-bound dose is much lower than the dose of 19 rad that is the 

lower limit of the 95 percent confidence interval for a threshold dose for Stage I posterior 

subcapsular cataracts quoted by the VA (2011). Therefore, the maximized upper-bound dose to 

the lens of the eye estimated here can be assigned during ECUP expedited processing of cataract 

cases for all ECUP veterans.

5.2 Organ and Skin Site Exclusions from Expedited Processing

To determine exclusions of EPG/organ combinations from automatic expedited 

processing based on exceeding applicable limiting doses, the EPG TODs of the 24 standard 

organs for each EPG shown in Table 13 are compared with the applicable organ cancer/disease

LDα values listed in Table 1. This evaluation process is discussed in detail in Section 2. If an 

EPG TOD is equal to or higher than its applicable limiting dose, it is recommended that the

EPG/organ combination be excluded from automatic expedited processing. Only the EPG/organ 

combinations for which the NIOSH-IREP estimated probability of causation is lower than 

40 percent are deemed eligible for automatic expedited processing.

Of these EPG/organ dose comparisons to LDα values, EPG TODs for only two 

EPG/organ combinations, or approximately 2 percent of all EPG/organ combinations, are equal 

to or higher than the respective LDα; these are shown in Table 15. Cases involving all other 

organs and cancer models in all ECUP EPGs may be expedited by assigning the upper-bound 

external, internal alpha, and internal beta+gamma doses in Table 13. As discussed earlier, the 

limiting doses based on acute alpha radiation (LDα) were assumed to be appropriate for 

comparison with ECUP EPG organ doses because the TODs for several organs are dominated by 

alpha radiation, and LDα values are generally lower than LDγ values (Table 1). For the few 

organs and cancer models that have lower LDγ values than LDα values, the EPG TODs are well 

below both the LDγ and LDα values and comparison with either value results in the same 

conclusion. Finally, the EPG TODs for the two EPG/organ combinations that are higher than the 

respective LDα are both dominated by alpha radiation. 
42

Table 15. EPG and organ combinations not recommended for expedited processing 

ECUP EPG ECUP Standard Organ NIOSH-IREP Cancer Model

Soil Removal Workers Bone Surface Bone

Liver Liver, Gallbladder

Northern Island Workers None n/a

Lojwa Support Workers None n/a

Southern Island Workers None n/a

To determine exclusions of EPG/cancer/race category/skin site combinations from 

automatic expedited processing based on exceeding applicable limiting doses, the total upperbound skin doses for 17 skin sites are compared with LDα values for three types of skin cancers 

and two combined groups of races. Three races are merged into the first grouping (Table 16), and 

two races are combined into the second grouping (Table 17), based on similarity of LDα values.

Decisions on expediting skin dose cases should be based on the recommendations and doses 

shown in Table 16 and Table 17. Total doses for 74 of the 408 EPG/cancer/race category/skin 

site combination doses (approximately 18 percent) exceed the applicable LDα values. These are 

limited to skin sites with malignant melanoma and basal cell carcinoma in three of the four 

ECUP EPGs, as shown in Table 16 and Table 17. Similar to internal organ dose comparisons, the 

limiting doses based on acute alpha radiation (LDα) were assumed to be appropriate for 

comparison with ECUP EPG skin doses because the estimated upper-bound skin doses for many 

of the skin sites are dominated by alpha radiation from dermal contamination. The comparison to 

LDα values to determine exclusions is acceptable for the skin sites that are not dominated by 

alpha radiation because the upper-bound doses for these sites are less than the LDα values for all

three skin cancer types in all races. 
43

Table 16. Recommendations for EPG dose assignments for skin cancer cases for “American Indian or Alaska Native”,

“Asian, Native Hawaiian, or other Pacific Islander”, and “Black” participants

Skin Site

EPG/Cancer/Skin Site Combinations that are Recommended (green) and 

Not Recommended (red) for ECUP Expedited Processing *,†,‡

Soil Removal Northern Islands Lojwa Support Southern Islands

MM BCC SCC MM BCC SCC MM BCC SCC MM BCC SCC

Scalp

Face

Forehead

Behind ear

Neck

Back of neck

Shoulder

Chest

Torso (backside)

Under belt

Forearm

Upper leg

Palm

Back of hand

Lower leg

Sole of foot

Under boot edge

* MM = malignant melanoma. LDα values for MM are 1.0–1.8 rem for the participants represented in this table; an LDα of 1.0 rem is used for 

expedited processing recommendations.

BCC = basal cell carcinoma. The BCC LDα value for all participants represented in this table is 0.85 rem.

SCC = squamous cell carcinoma cases. The SCC LDα value for all participants represented in this table is 63 rem.

† Red-shaded table cells indicate EPG/Skin cancer/Skin site combinations that are not recommended for expedited processing for the participants 

represented in this table (see Table caption).

‡ Green-shaded table cells shaded green indicate EPG/Skin cancer/Skin site combinations that are recommended for expedited processing for the 

participants represented in this table (see Table caption), with assignment of the applicable dose from Table 14.
44

Table 17. Recommendations for EPG dose assignments for skin cancer cases for

“White (Hispanic)” and “White (Non-Hispanic)” participants

Skin Site

EPG/Cancer/Skin Site Combinations that are Recommended (green) and 

Not Recommended (red) for ECUP Expedited Processing*,†,‡

Soil Removal Northern Islands Lojwa Support Southern Islands

MM BCC SCC MM BCC SCC MM BCC SCC MM BCC SCC

Scalp

Face

Forehead

Behind ear

Neck

Back of neck

Shoulder

Chest

Torso (backside)

Under belt

Forearm

Upper leg

Palm

Back of hand

Lower leg

Sole of foot

Under boot edge

* MM = malignant melanoma. LDα values for MM are 2.1–2.4 rem for the participants represented in this table; an LDα of 2.1 rem is used for 

expedited processing recommendations.

BCC = basal cell carcinoma. LDα values for BCC are 2.4–2.5 rem for the participants represented in this table; an LDα of 2.4 rem is used for 

expedited processing recommendations.

SCC = squamous cell carcinoma cases. LDα values for SCC are 165–175 rem for the participants represented in this table; an LDα of 165 rem is 

used for expedited processing recommendations.

† Red-shaded table cells indicate EPG/Skin cancer/Skin site combinations that are not recommended for expedited processing for the participants 

represented in this table (see Table caption).

‡ Green-shaded table cells indicate EPG/Skin cancer/Skin site combinations that are recommended for expedited processing for the participants 

represented in this table (see Table caption), with assignment of the applicable dose from Table 14.
45

6.

References

AEC (United States Atomic Energy Commission, Nevada Operations Office), 1973. Enewetak 

Radiological Survey, Vol I. NVO-140, United States Atomic Energy Commission, 

Nevada Operations Office, Las Vegas, NV. October.

Case, D. R., Chehata, M., Dunavant, J. D., Egbert, S. D., Mason, C. L., McKenzie-Carter, M. A., 

Singer, H. A., and Weitz, R. L., 2011. A Technical Approach to Expedited Processing of 

NTPR Radiation Dose Assessments. DTRA-TR-10-29, Defense Threat Reduction Agency. 

Fort Belvoir, VA. October 17. 

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territories of the United States, to amend certain acts relating thereto, and for other 

purposes. House of Representative Bill 6550, 95th Congress (Second Session). 

Washington, DC. September 30.

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Nuclear Agency, Washington, D.C.

DTRA (Defense Threat Reduction Agency), 2018. Radiation Dose Assessment for Military 

Personnel of the Enewetak Atoll Cleanup Project (1977-1980). DTRA-TR-17-003. 

Defense Threat Reduction Agency, Fort Belvoir, VA, April 13. 

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Personnel of the Enewetak Atoll Cleanup Project (1977-1980), Revision 1. 

DTRA-TR-17-003(R1). Defense Threat Reduction Agency, Fort Belvoir, VA, April 30. 

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Operating Procedures for Radiation Dose Assessments – List and Overview (Revision 1). 

Update: April 2021. DTRA-SOP-17-01(R1), Defense Threat Reduction Agency, Fort 

Belvoir, VA. April 30.

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Coefficients: Workers and Members of the Public, Version 3.0. The International 

Commission on Radiological Protection, Ottawa, Ontario. 

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Physiological Data for Use in Radiological Protection Reference Values. ICRP 

Publication 89. Ann. ICRP 32 (3-4). International Commission on Radiological 

Protection, Ottawa, Ontario.

McKenzie-Carter, M. and Egbert, S. 2015. Technical Basis for Expedited Processing of 

Radiation Dose Assessments for NTPR Hiroshima and Nagasaki Participants.

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RadioEpidemiological Program, NIOSH-IREP ver. 5.9. National Institute for 
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Occupational Safety and Health, Washington, DC. December. Available at: 

https://irep.oraucoc.org/, accessed August 25, 2021.

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Agents Service (10P3A) to Director, Compensation Service (211B). April 25.
47

Appendix A.

Inhalation and Ingestion Dose Coefficients

The tables in this Appendix contain the ICRP 68 dose coefficients used for the estimation 

of ECUP EPG internal organ doses for inhalation (Table A-1) and ingestion (Table A-2). 
48

Table A-1. ICRP 68 Organ Inhalation Dose Coefficients (rem pCi−1) *

Organ/Tissue† Co-60

(Type M)

Sr-90

(Type F)

Cs-137

(Type F)

Pu-239

(Type M)

Am-241

(Type M)

Adrenals 2.4110−8 2.2210−9 1.8110−8 9.2510−6 9.9910−6

Bladder Wall 8.8810−9 4.8110−9 1.8510−8 9.2510−6 9.9910−6

Bone Surface 1.3710−8 1.3710−6 1.7810−8 5.5510−3 5.9210−3

Brain 7.0310−9 2.2210−9 1.5210−8 9.2510−6 9.9910−6

Breast 2.1510−8 2.2210−9 1.4410−8 9.2510−6 9.9910−6

Esophagus 2.5210−8 2.2210−9 1.6710−8 9.2510−6 9.9910−6

Stomach Wall 1.5910−8 2.2910−9 1.7010−8 9.2510−6 9.9910−6

SI Wall 1.2210−8 2.4110−9 1.8110−8 9.2510−6 9.9910−6

ULI Wall 1.4410−8 7.0310−9 1.8510−8 9.2510−6 9.9910−6

LLI Wall 1.8110−8 1.9210−8 2.1510−8 9.2510−6 9.9910−6

Colon 1.5910−8 1.2210−8 1.9610−8 9.2510−6 9.9910−6

Kidneys 1.4110−8 2.2210−9 1.7410−8 2.1810−5 3.0010−5

Liver 3.0010−8 2.2210−9 1.7410−8 1.1110−3 3.5910−4

Muscle 1.3310−8 2.2210−9 1.6310−8 9.2510−6 9.9910−6

Ovaries 1.1510−8 2.2210−9 1.8510−8 7.0310−5 1.1510−4

Pancreas 2.0010−8 2.2210−9 1.8510−8 9.2510−6 9.9910−6

Red Marrow 1.5210−8 5.9210−7 1.6710−8 2.5910−4 2.0410−4

ET Airways 6.2910−8 6.6610−9 2.8910−8 3.5210−5 3.6610−5

Lungs 1.8110−7 2.2910−9 1.6310−8 1.1110−4 1.2610−4

Skin 8.5110−9 2.2210−9 1.3710−8 9.2510−6 9.9910−6

Spleen 1.8510−8 2.2210−9 1.7410−8 9.2510−6 9.9910−6

Testes 7.0310−9 2.2210−9 1.6310−8 7.0310−5 1.1510−4

Thymus 2.5210−8 2.2210−9 1.6710−8 9.2510−6 9.9910−6

Thyroid 1.3310−8 2.2210−9 1.6710−8 9.2510−6 9.9910−6

Uterus 9.9910−9 2.2210−9 1.8510−8 9.2510−6 9.9910−6

* ICRP 68 dose coefficients for a particle size of 1 μm AMAD were obtained from ICRP (2011). The dose 

coefficients for each radionuclide correspond to the absorption type indicated. 

† Abbreviations used in this table: SI = Small Intestine; ULI = Upper Large Intestine; LLI = Lower Large 

Intestine; ET = Extra-thoracic
49

Table A-2. ICRP 68 Organ Ingestion Dose Coefficients (rem pCi−1) *

Organ/Tissue† Co-60

(f1=0.1)

Sr-90

(f1=0.3)

Cs-137

(f1=1.0)

Pu-239

(f1=0.0005)

Am-241

(f1=0.0005)

Adrenals 9.2510−9 2.4410−9 5.1810−8 5.1810−8 5.5510−8

Bladder Wall 9.6210−9 5.5510−9 5.1810−8 5.1810−8 5.5510−8

Bone Surface 7.4010−9 1.5210−6 5.1810−8 3.0310−5 3.3310−5

Brain 5.1810−9 2.4410−9 4.4410−8 5.1810−8 5.5510−8

Breast 4.8110−9 2.4410−9 4.0710−8 5.1810−8 5.5510−8

Esophagus 6.2910−9 2.4410−9 4.8110−8 5.1810−8 5.5510−8

Stomach Wall 9.2510−9 3.3310−9 4.8110−8 5.5510−8 5.9210−8

SI Wall 1.5510−8 4.0710−9 5.1810−8 6.2910−8 6.6610−8

ULI Wall 2.4110−8 2.1510−8 5.1810−8 1.1810−7 1.3010−7

LLI Wall 4.4410−8 8.1410−8 6.2910−8 2.4810−7 2.7410−7

Colon 3.2210−8 4.8110−8 5.5510−8 1.7410−7 1.9210−7

Kidneys 8.8810−9 2.4410−9 4.8110−8 1.2210−7 1.7010−7

Liver 1.6310−8 2.4410−9 4.8110−8 6.2910−6 2.0010−6

Muscle 7.0310−9 2.4410−9 4.4410−8 5.1810−8 5.5510−8

Ovaries 1.5910−8 2.4410−9 5.1810−8 4.0710−7 6.2910−7

Pancreas 9.6210−9 2.4410−9 5.1810−8 5.1810−8 5.5510−8

Red Marrow 7.7710−9 6.6610−7 4.8110−8 1.4410−6 1.1510−6

ET Airways 6.2910−9 2.4410−9 4.8110−8 5.1810−8 5.5510−8

Lungs 6.6610−9 2.4410−9 4.8110−8 5.1810−8 5.5510−8

Skin 4.8110−9 2.4410−9 4.0710−8 5.1810−8 5.5510−8

Spleen 7.7710−9 2.4410−9 4.8110−8 5.1810−8 5.5510−8

Testes 6.6610−9 2.4410−9 4.4410−8 4.0710−7 6.2910−7

Thymus 6.2910−9 2.4410−9 4.8110−8 5.1810−8 5.5510−8

Thyroid 6.2910−9 2.4410−9 4.8110−8 5.1810−8 5.5510−8

Uterus 1.1110−8 2.4410−9 5.1810−8 5.1810−8 5.5510−8

* ICRP 68 dose coefficients were obtained from ICRP (2011). The dose coefficients for each radionuclide 

correspond to the elemental fractional uptake from the GI tract (f1 value) as indicated. 

† Abbreviations used in this table: SI = Small Intestine; ULI = Upper Large Intestine; LLI = Lower Large 

Intestine; ET = Extra-thoracic
50

Abbreviations, Acronyms, and Symbols

AEC Atomic Energy Commission

aka also known as

ALL acute lymphocytic leukemia 

Am americium

AMAD activity median aerodynamic diameter

AML acute myeloid leukemia

BCC basal cell carcinoma

CFR Code of Federal Regulations

Ci curie

CJTG Commander, Joint Task Group

CLL chronic lymphocytic leukemia 

cm centimeter

CML chronic myeloid leukemia 

Co cobalt

Cs cesium

d day

DNA Defense Nuclear Agency

DNA/JTG Defense Nuclear Agency/Joint Task Group

DoD Department of Defense

DTRA Defense Threat Reduction Agency

ECUP Enewetak Atoll Cleanup Project

EPG expedited processing group

ET extra-thoracic

Eu europium

FB film badge

FCDNA Field Command, Defense Nuclear Agency

g gram

h hour

in inch

ICRP International Commission on Radiological Protection

IREP Interactive RadioEpidemiological Program

JTG Joint Task Group

keV kiloelectron volt

LD limiting dose

kg kilogram

LDα limiting dose based on alpha radiation

LDγ limiting dose based on gamma radiation

LLI lower large intestine

m meter

MEDEVAC medical evacuation

MM malignant melanoma

μR microroentgen

mo month
51

mph mile per hour

NIOSH National Institute for Occupational Safety and Health

NTPR Nuclear Test Personnel Review 

PC probability of causation

pCi picocurie

POW prisoner of war

PSC posterior subcapsular cataract

Pu plutonium

R roentgen

rad radiation absorbed dose

RDA radiation dose assessment 

rem roentgen equivalent man

RSAIT Radiation Safety Audit and Inspection Team

s second

SAR search and rescue 

Sb antimony

SCC squamous cell carcinoma

SI small intestine

SM standard method

SOP standard operating procedure

Sr strontium

TLD thermoluminescent dosimeter

TOD total organ dose

TRU transuranic

UB α upper-bound alpha dose

UB β+γ upper-bound beta+gamma dose

ULI upper large intestine

U.S. United States

USNRC United States Nuclear Regulatory Commission

VA Department of Veterans Affairs

VBDR Veterans’ Board on Dose Reconstruction

VIP very important person

wk week

y year

yd yard