SEC Petition Evaluation Report
 

Petition SEC-00020
 

Report Rev # 0 Report Submittal Date: 10-20-2005 

Petition Administrative Summary 

Petition Under Evaluation 

Petition # Petition 

Type 

Submittal Date DOE/AWE Facility Name 

SEC-00020 83.13 01-03-2005 Pacific Proving Ground (PPG) 

Feasible to Estimate Doses with Sufficient Accuracy? 

Single Class Multiple Classes Determination Established for All Classes 

Yes No X Yes No Yes X No 

Initial Class Definition 

All scientists and scientific couriers employed at Enewetak Atoll during Operation HARDTACK I, from July 1, 

1958 through August 31, 1958. 

Proposed Class Definition 

All employees of DOE, DOE contractors, or subcontractors employed at the PPG from 1946 through 1962. 

Related Petition Summary Information 

SEC Petition Tracking #(s) Petition Type DOE/AWE Facility Name Petition Status 

None 

Related Evaluation Report Information 

Report Title DOE/AWE Facility Name 

None 

ORAU Lead Technical Evaluator: Signature on File 

Monica Harrison-Maples 

10/20/2005 

Date 

Lead Technical Evaluator: Signature on File 

LaVon Rutherford 

10/20/2005 

Date 

Reviewed By: Signature on File 

James W. Neton 

10/20/2005 

Date 

Approved By: Signature on File 

Larry J. Elliott 

10/20/2005 

Date 

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Evaluation Summary 

This evaluation report by the National Institute for Occupational Safety and Health (NIOSH) covers a class 

of employees proposed for addition to the Special Exposure Cohort (SEC) in Petition SEC00020, qualified 

on April 11, 2005. Although the petition requested NIOSH to consider all scientists and scientific couriers 

located at the Enewetak Atoll, a location within the Pacific Proving Grounds (PPG), during Operation 

HARDTACK I from July 1 through August 31, 1958, this evaluation covers all employees of Department of 

Energy (DOE), DOE contractors, or subcontractors employed at the PPG from 1946 through 1962. 

In this evaluation report, NIOSH provides its findings on the feasibility of estimating radiation doses of 

members of this class with sufficient accuracy (i.e., the feasibility of dose reconstruction) and on related 

matters, as required for NIOSH evaluations of SEC petitions under the Energy Employees Occupational 

Illness Compensation Program Act of 2000 (EEOICPA) and title 42 of the Code of Federal Regulations 

(CFR), Part 83, Procedures for Designating Classes of Employees as Members of the Special Exposure 

Cohort Under the Energy Employees Occupational Illness Compensation Program Act of 2000 (42 CFR pt. 

83). This report will be considered by the Advisory Board on Radiation and Worker Health and by the 

Secretary of Health and Human Services (HHS). The Secretary of HHS will make final decisions 

concerning whether or not to add one or more classes to the SEC in response to the petition addressed by 

this report. 

Feasibility of Dose Reconstruction 

The feasibility determination for the class of employees covered by this evaluation report is governed by, 

section 83.13(c)(1) of 42 CFR pt. 83. Under this regulation, NIOSH must establish whether or not it has 

access to sufficient information to either estimate the maximum radiation dose, for every type of cancer for 

which radiation doses are reconstructed, that could have been incurred under plausible circumstances by any 

member of the class, or to estimate the radiation doses of members of the class more precisely than a 

maximum dose estimate. If NIOSH has access to information sufficient for either case, then dose 

reconstruction is feasible. 

NIOSH has established in this evaluation that it lacks access to sufficient information to estimate either the 

maximum radiation dose incurred by any member of the class being evaluated, or to estimate such radiation 

doses more precisely than a maximum dose estimate. The sum of information from the available resources 

is insufficient to document or estimate the potential maximum internal exposure to members of the class, 

under plausible circumstances during the period of AEC operations at the PPG, 1946 through 1962. There 

does appear to be sufficient information and data, however, to estimate most or all external radiation 

exposures to members of this class. 

Health Endangerment 

The health endangerment determination for the class of employees covered by this evaluation report is 

governed by EEOCIPA and 42 C.F.R. Part 83.13(c)(3). Under these requirements, if it is not feasible to 

estimate with sufficient accuracy radiation doses for members of the class, NIOSH must also make a 

determination whether or not there is a reasonable likelihood that such radiation doses may have endangered 

the health of members of the class. The regulation requires NIOSH to assume that any duration of 

unprotected exposure may have endangered the health of members of a class when it has been established 

that the class may have been exposed to radiation during a discrete incident likely to have involved levels of 

exposure similarly high to those occurring during nuclear criticality incidents. 

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If the occurrence of such an exceptionally high level exposure has not been established, then NIOSH is 

required to specify that health was endangered for those workers who were employed for a number of work 

days aggregating at least 250 work days within the parameters established for the class or in combination 

with work days within the parameters established for one or more other classes of employees in the SEC 

(excluding aggregate work day requirements). 

The NIOSH evaluation did not identify any evidence from the petitioners or from other resources that would 

establish that the class was exposed to radiation during a discrete incident likely to have involved 

exceptionally high level exposures, as described above. Consequently, NIOSH has specified that health was 

endangered for those workers covered by this evaluation who were employed for a number of work days 

aggregating at least 250 work days within the parameters established for this class or in combination with 

work days within the parameters established for one or more other classes of employees in the SEC. 

Proposed Class Definition 

This evaluation defines a single class of employees for which NIOSH cannot estimate radiation doses with 

sufficient accuracy and whose health may have been endangered by such radiation doses. This class 

includes all employees of DOE, DOE contractors, or subcontractors employed at the PPG from 1946 

through 1962 for a number of work days aggregating at least 250 work days occurring either solely under 

this employment or in combination with work days within the parameters (excluding aggregate work day 

requirements) established for other classes of employees included in the SEC. 

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1.0 Purpose 

The purpose of this report is to provide an evaluation of the feasibility of reconstructing the dose for the 

employees proposed as a class in SEC petition 00020. The petition covered scientists and scientific 

couriers, radiation safety monitors, and construction workers who were Atomic Energy Commission (AEC) 

employees, contractors, or subcontractors at the Pacific Proving Ground (PPG) from January 1946 through 

December 1962. The evaluation was initially based on the petition, SEC00020 which defines a class limited 

to “scientists and scientific couriers located at the Enewetak Atoll, a location within the Pacific Proving 

Grounds (PPG), during Operation HARDTACK I from July 1 through August 31, 1958.” The evaluation class 

definition is being extended to include personnel for whom NIOSH has identified a plausible scenario for 

ingestion or inhalation of radiological particles in the air due to the re-suspension of fallout and a lack of 

internal monitoring data. 

This evaluation was conducted in accordance with the requirements of 42 C.F.R. Part 83 and the guidance 

contained in the National Institute for Occupational Safety and Health (NIOSH) Internal Procedures for 

Special Exposure Cohort (SEC) Evaluations, OCAS-PR-004. It provides information and analyses germane 

to considering a petition for adding a class of employees to the SEC. It does not provide any determinations 

concerning the feasibility of dose reconstruction that necessarily apply in the particular case of any 

individual energy employee who might require a dose reconstruction from NIOSH. 

2.0 Introduction 

Energy Employees Occupational Illness Compensation Program Act (EEOICPA) and 42 C.F.R. Part 83 

requires NIOSH to evaluate qualified petitions requesting Department of Health and Human Services 

(HHS) to add a class of employees to the SEC. The evaluation is intended to provide a fair, science-based 

determination of whether or not it is feasible to estimate with sufficient accuracy the radiation doses of the 

class of employees through NIOSH dose reconstructions1 . If it is not feasible, the evaluation is further 

required to make a determination with respect to the health endangerment of the class of employees. 

NIOSH is required to document the evaluation in a report, which is provided to the petitioners and to the 

President’s Advisory Board on Radiation and Worker Health (the Board). The Board will consider the 

NIOSH evaluation report, together with the petition and any comments of the petitioner(s), to make 

recommendations to the Secretary of HHS on whether or not to add one or more classes of employees to the 

SEC. Once NIOSH has received and considered the advice of the Board, the Director of NIOSH will 

propose decisions on behalf of HHS. The Secretary of HHS will make final decisions, taking into account 

the NIOSH evaluation, the advice of the Board, and the proposed decision issued by NIOSH. As part of this 

final decision process, the petitioner(s) may seek a review of certain types of proposed decisions issued by 

NIOSH.2 

This NIOSH report provides a summary of the methods and findings of the NIOSH SEC petition evaluation 

for all employees of DOE, DOE contractors, or subcontractors employed at the PPG from 1946 through 

1962. 

1

 NIOSH dose reconstructions under EEOICPA are performed using the methods promulgated under 42 CFR Part 82 and the 

detailed implementation guidelines available at www.cdc.gov/niosh/ocas. 

2

 See 42 CFR Part 83 for a full description of the procedures summarized here. Additional internal procedures are available at
 

www.cdc.gov/niosh/ocas. 

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3.0 Initial Class Definition and Petition Basis 

The initial class definition, as specified within SEC Petition SEC00020, which qualified on April 11, 2005, 

requested HHS to consider the addition of a class of employees including the scientists and scientific 

couriers employed at Enewetak Atoll during Operation HARDTACK I, from July 1 through August 31, 1958 

to the SEC. 

Of the evidence provided by the petitioners, the following evidence met the criteria in the rule to provide 

support of their belief that dose reconstruction would not be feasible for this proposed class of employees, to 

qualify the submission as a petition to receive consideration by NIOSH, the Board, and HHS: 

•	 As of the time of qualification, no data or documentation had been located indicating any 

results or program to monitor for internal exposure due to ingested or inhaled radioactive 

material. The petitioner provided a declaration that there was no monitoring for internal 

exposures due to ingested or inhaled radioactive material. 

The petitioners supplied an affidavit in support of this basis. 

4.0 Data Resources 

NIOSH identified and reviewed multiple data resources to determine the availability of information relevant 

to determining the feasibility of dose reconstruction for the class of employees covered by the evaluation. 

This included determining the availability of information on personal monitoring, area monitoring, testing 

processes, and radiation source materials for the period of time from 1946 through 1962 at PPG. The 

following sections identify the resources identified and reviewed. 

4.1 Previous Dose Reconstructions 

NIOSH reviewed its dose reconstruction database, NIOSH OCAS Claims Tracking System (NOCTS), to 

identify dose reconstruction cases under EEOICPA that might provide information relevant to the petition 

evaluation. Table 1 below provides a results summary of this review for the 

1946 through 1962 time frame. 

. 

Table 1: PPG Claims Submitted Under Dose Reconstruction Rule for 1946-1962 

Description Total 

Number of cases submitted for energy employees who meet the 

revised class definition employment period criteria. 65 

Number of dose reconstructions completed for energy employees 

who were employed at PPG during the years identified in the 

revised class definition. 

3 

Number of cases for which internal dosimetry records were 

obtained for the identified years in the revised class definition. 0 

Number of cases for which external dosimetry records were 

obtained for the identified years in the revised class definition. 57 

NIOSH reviewed each case to determine whether internal and/or external personal monitoring records for 

the employee or any other monitoring records for the employee were available. While there was an external 

monitoring program and most claimants have been determined to have external monitoring records, no 

5 of 38 
 

records of inhalation or ingestion monitoring for these individuals associated with potential internal 

exposure received at the PPG were available to NIOSH. References to individual internal monitoring were 

made in several historical reports on specific test series. Records of the computer aided telephone interviews 

with many of the claimants were reviewed as well, for any information that might identify monitoring 

practices and record locations. The interviews provided some information that might be useful for dose 

reconstructions (i.e., work locations, hours worked, and hazards encountered) and most of the claimants 

indicated that they wore a film badge. 

NOCTS currently indicates that a total of 65 cases requiring dose reconstruction (as of September 28, 2005) 

have been received for the PPG facility. Four of those cases have been held by Department of Labor for 

some form of clarification, which makes them unavailable to NIOSH at this time. Of the available cases 

received to date, dose reconstruction has been completed for 3 claims (4.9% of the available active claims). 

4.2 NIOSH and ORAU Research Documents 

A search of the NIOSH site research database was conducted for documentation relating to PPG and the 

resulting 6 documents were evaluated for pertinence to this petition. In addition, multiple publicly 

accessible websites were searched including the Internal Dose Monitoring website of Lawrence Livermore 

National Laboratory, the Defense Threat Reduction Agency (DTRA) website, and the Department of 

Energy Environment, Safety and Health webpage regarding the Marshall Islands. The Marshall Islands 

Document Collection was searched for all documents pertaining to the various atmospheric nuclear testing 

operations performed at the PPG. 

These documents contained event histories, summary external monitoring dosimetry results (film badge 

summary readings of gamma exposure), the Department of Defense (DOD) Consolidated Dosimetry Report, 

final reports of various task groups assigned specific responsibilities within the JTF organizations 

conducting the testing, contractor environmental survey reports, and standard operating procedures. 

The information from these documents relevant to the class is summarized and evaluated in sections 5.0, 

6.0, and 7.0 of this report. 

4.3 Documentation and/or affidavits provided by the petitioners 

In qualifying and evaluating the petition, NIOSH reviewed the following documents submitted or 

referenced by the petitioners: 

1) Affidavit of petitioner, received March 7, 2005. 

2) Excerpts from the book “The Leukemias: Epidemiologic Aspects” by Martha S. Linet, 1985, 

received January 3, 2005. 

These documents were reviewed as to the relevance to the petitioning class. The information from these 

documents, relevant to the petitioning class, has been summarized in sections 5.0 and 7.0 of this report. 

5.0 Summary of Available Monitoring Data 

Each of the test series had a radiation safety (radsafe) program established, incorporating procedures 

developed in accordance with lessons learned from previous test series (DNA 6041F). These programs 

focused primarily on personal monitoring of external radiation exposure. Internal exposure was to be 

controlled through avoidance and detection as indicated in operational radiological safety procedures. A 

substantial bioassay program was not implemented for participants of the operation. There was no program 

6 of 38 
 

 

 

for whole body or chest counting, and there was only a brief mention, located in the Albuquerque 

Operations manager’s report (ALO 58-2), of limited use of nasal smears, for which NIOSH has been unable 

to locate the associated data. 

TABLE 5.1 SUMMARY OF MONITORING DATA FOR PPG 

Available Data Qualifications on data 

External Dosimetry 

Data 

Considerable personal monitoring data and 

area monitoring data are available for 

gamma. 

Protective covering on badges 

potentially shielded out betas. 

Reports of defective seal on 

badges for DOMINIC I. 

Neutron Dosimetry 

Data 

Experimental studies were conducted to 

explore neutron generation and measurement 

Experiments did not include 

information on the exposure of 

test participants. 

Internal Dosimetry 

Data 

None located in publicly accessible records. 

Based on conversations with SAIC, who is 

responsible for DTRA dose reconstructions, 

the urine and air data for evaluation of 

internal exposures are not available. 

As noted by the National 

Research Council (NRC) (NRC 

2003) suitable monitoring data to 

estimate intakes of radionuclides 

generally were not obtained. 

Other than a number of urine 

samples analyzed during 

Operation CROSSROADS, 

bioassays were rare among 

personnel. 

Environmental Reports of radioactivity results in sea water, 

Sampling Data lagoon water sampling, beta activity in 

plankton, and surveys of plant, fish and 

invertebrate samples from all around the 

PPG were completed by University of 

Washington. Public Health Service sampled 

air, rain, and fallout at locations in and 

surrounding the PPG. 

Air Sampling Data Sampling protocols differed for the different 

test series, but were collected according to 

operational plan, i.e. for HARDTACK I 

samples were collected daily or 48 hours 

after detonation. 

No occupational air data has been retrieved 

to date. Some offsite monitoring data is 

available. 

Some samples were only counted 

once and activity values were 

extrapolated to the end of the 

collection. 

An example of the type of data that is typically seen in test reports, are described below. 

Sample type Number of samples 

Sea water 463 

Rain water 29 

Fresh water 2 

Alpha swipes 60 

Nasal smears 200 

Food 15 

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Soil 13 

Urine (tritium) 20 

Marine specimens 6 

Plant specimens 3 

This information was taken from a report of the Albuquerque Operations Manager (ALO 58-2). The report 

references that the samples were counted during HARDTACK I, but no data from these samples have been 

located as of the date of this evaluation report. The number of samples varied with each test shot, but no 

data from the test shots have been located at this time. 

Since 1946, personnel from the School of Fisheries, University of Washington have studied the effects of 

nuclear detonations and the ensuing radioactivity on the marine and terrestrial environments throughout the 

Central Pacific (UW). A collection of reports and publications about these activities and a collection of 

several thousand samples from these periods are reportedly kept at the School of Fisheries. The basic field 

program was the collection of terrestrial, lagoon, and ocean samples that represented the major components 

of the ecosystem. Some of the identification and measurement of the radionuclides in the samples was done 

in the field to provide guidance to the on-going field program, but most of the samples were analyzed in the 

home laboratory where the facilities were available for more sensitive detection and measurement and 

longer sample counting times could be accommodated. This data, which might be available from the 

University of Washington, may be useful for calculating ingestion from swimming in the lagoons and eating 

marine life (UW and UW 40). 

Since its inception in 1978, the Nuclear Test Personnel Review (NTPR) program has provided radiation 

dose information and data to veterans who participated in U.S. atmospheric nuclear tests, served with the 

American occupation forces in Hiroshima and Nagasaki, Japan, or were prisoners of war in Japan at the 

conclusion of World War II. The program is administered by the Defense Threat Reduction Agency 

(DTRA), which is the Department of Defense (DOD) Executive Agent for the NTPR Program. NIOSH 

contacted Science Applications International Corporation (SAIC), the contractor retained by DTRA to 

complete dose reconstructions for veterans meeting the criteria identified above, to determine the 

availability of urine and air sample data for test shots conducted at PPG. SAIC technical experts indicated 

that the 2600 urine samples identified for CROSSROADS were unavailable. SAIC also indicated few, if any, 

air sample data, are available. 

There is no NIOSH Technical Basis Document (TBD) for PPG but the TBD for Nevada Test Site (NTS) has 

information pertinent to this evaluation. More extensive atmospheric testing was conducted at the NTS than 

at PPG. The NTS nuclear weapons testing monitoring results are a useful source of information on the 

deposition of specific radionuclides resulting from nuclear weapons testing. 

6.0 Summary of Radiological Operations Relevant to the Initial Class 

This summary is based in part on a review of individual project task reports for each test series. This 

information was confirmed, in part, by a review of the Defense Nuclear Agency report, “For the Record- A 

History of the Nuclear Test Personnel Review Program, 1978-1986” (DNA 6041F). 

Between 1945 and 1962, the U.S. Atomic Energy Commission (AEC) conducted 235 atmospheric nuclear 

weapon tests at sites in the U.S. and in the Pacific and Atlantic oceans. In the Pacific, 29 atolls and 5 islands 

spread over 770,000 mi2

 with a total land area of about 70 mi2 comprise the Marshall Islands. Enewetak 

Atoll, Bikini Atoll, Johnston Island and Christmas Island in the Marshall Islands together, are the AEC’s 

Enewetak Proving Ground, later known as the Pacific Proving Ground (PPG). The table below identifies 

the test series, the year they occurred, the number of detonations, and the various types of detonations. 

8 of 38 
 

Pacific Test Series Name Year Conducted No. of 

Detonations 

Type of Detonation 

Crossroads 1946 2 Airburst/Underwater 

Sandstone 1948 3 All Tower 

Greenhouse 1951 4 All Tower 

Ivy 1952 2 Surface/ Airburst 

Castle 1954 6 Surface/ Barge 

Redwing 1956 17 Surface, Airdrop, 

Barge, and Tower 

Hardtack I 1958 35 Various 

Dominic 1962 36 Airdrop 

Note: For more detail on each test see Appendix A 

All of the test series were conducted by organizations designated as a Joint Task Force (JTF), made up of 

military personnel from the four services, federal civilian personnel, and contractor personnel. 

From the beginning of the tests, military leadership recognized the need for a substantial, qualified, military 

radsafe organization. After CROSSROADS, the radiation safety plans established an organization to provide 

radsafe expertise and services to commanders of the separate components of the task force, who were 

responsible for personnel safety within their commands. Personnel were trained in radiological safety. 

Standards governing permissible exposure were established. 

The principal source of exposure to DOE, DOE contractors, or subcontractors, or AWE employees 

employed by the AEC or AEC contractors or subcontractors at the PPG from 1946 through 1962 would 

have been external exposure from gamma rays following detonation, fallout, the activation of debris (i.e. 

photo tower steel), contamination and immersion. Beta exposure would occur from cloud immersion and 

direct contact with fallout. Neutron exposure would have been a concern near the blast. The principal 

potential source of internal radiation doses for members of the class would have been inhalation or ingestion 

due to contamination caused by the fallout from the nuclear detonations. 

Operation CROSSROADS was the first atmospheric nuclear weapon test series held in the Marshall Islands 

starting in 1946. From the beginning of the nuclear testing, Radiological Safety Plans focused on detection 

and avoidance of radiation (DNA 6032F). The plans included the establishment of exclusion areas, 

operational limits, and contamination controls (including donning and doffing clothing upon egress from 

potentially contaminated areas). Systematic reconnaissance was to begin shortly after each detonation with 

aerial and surface surveys, including water samples, soil samples, and marine life samples. Radsafe 

monitors were assigned to monitor and limit the radiation exposure of work parties. Over 225 monitors were 

used for each of the two CROSSROADS detonations. The Operational Plan set the maximum allowable dose 

for exposure over a long period at 0.1 roentgens (R) per 24 hours. In addition, no individual was allowed to 

have a total exposure of over 50 or 60 R in 2 weeks. If an individual received 10 R in 1 day or 60 R in 2 

weeks, he was to be withdrawn from active participation in the operation. There is no record indicating that 

this action was ever required (DNA 6032F). 

About 15 percent of the JTF 1 personnel were issued at least one of the 18,875 film-badge dosimeters 

during CROSSROADS. Approximately 6,596 personnel were on islands or ships that had no potential for 

radiation exposure. Personnel anticipated to be at greatest radiological risk were badged, and a percentage 

of each group working in less contaminated areas was badged. The maximum accumulated exposure 

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recorded was 3.72 R. Beginning with REDWING, film badges were issued to all individuals upon their 

arrival at the PPG to determine gamma radiation exposure (DNA 6032F; DNA 6041F). 

Due to the presence of alpha emitters, including plutonium, a program to urine test personnel thought to 

have been exposed was implemented to determine whether any had taken these substances into their bodies. 

The water-testing laboratory on the ship Haven was converted for testing urine. By 15 August 1946, 2600 

samples had been tested. The men doing the work had to use instruments that were on hand and develop 

techniques as they worked. The widespread presence of radioactive material led to high background counts 

and made it difficult to determine whether an individual had low levels of alpha emitters in his urine (DNA 

6032 F). 

The radiological safety approach used for CROSSROADS was duplicated for all tests after CROSSROADS. A 

radsafe annex to the Operation Plan, outlining the radiological safety regulations for the operation was 

issued prior to each test series. Exposure limits changed as more knowledge was gained from the tests. Air 

sampling was performed, but this was designed to establish fallout patterns rather than monitoring 

occupational internal exposure. According to SAIC, few of these air sampling data are available and 

NIOSH has not had the opportunity to examine them. Urine samples were collected for CROSSROADS but 

NIOSH has been unable to retrieve the data. After CROSSROADS, urine sampling was performed for special 

cases, such as after the occurrence of fallout a short time after zero hour of the DOG shot test during 

Operation GREENHOUSE. There were 125 urine samples analyzed, but these data are not available to 

NIOSH. 

Appendix A of this report provides more detail concerning each of the tests and radiological operations 

performed at the PPG. 

7.0 Evaluation of Feasibility of Dose Reconstruction 

The feasibility determination for the class of employees covered by this evaluation report is governed by 42 

CFR § 83.13(c) (1). Under this regulation, NIOSH must establish whether or not it has access to sufficient 

information to either estimate the maximum radiation dose that could have been incurred under plausible 

circumstances by any member of the class, or to estimate the radiation doses of members of the class more 

precisely than a maximum dose estimate. If NIOSH were to have access to the information sufficient for 

either case, then dose reconstruction would be feasible. 

In making determinations of feasibility, NIOSH begins by evaluating whether current or completed NIOSH 

dose reconstructions demonstrate the feasibility of estimating with sufficient accuracy the potential radiation 

doses of the class. If not, NIOSH systematically evaluates the sufficiency of different types of monitoring 

data and process and source or source term data, which together or individually might assure NIOSH that it 

can estimate either the maximum doses members of the class might have incurred, or more precise 

quantities that reflect the variability of exposures experienced by groups or individual members of the class. 

This approach is specified in the SEC Petition Evaluation Internal Procedures (OCAS-PR-004) available at 

www.cdc.gov/niosh/ocas. 

As documented in Section 4.1, NIOSH has not completed any dose reconstructions nor collected 

information in the process of dose reconstruction that fully demonstrates the feasibility of estimating the 

radiation doses of the class. As indicated in section 5.0, another government organization, DTRA has 

completed dose reconstructions for veterans associated with the nuclear weapons testing program at PPG. 

10 of 38 
The feasibility evaluation that follows examines the methods used for dose reconstruction under DTRA and 

the availability of information necessary for reconstructing internal and external radiation doses of members 

of the class. 

7.1 NTPR Dose Reconstructions 

As identified in section 5.0, a method for completing dose reconstructions for veterans who participated in 

U.S. atmospheric nuclear tests was developed by DTRA for the NTPR program, which serves veterans who 

participated in U.S. atmospheric nuclear tests, served with the American occupation forces in Hiroshima 

and Nagasaki, Japan, or were prisoners of war in Japan at the conclusion of World War II. The primary 

purpose of the NTPR Program is to provide participation data and radiation dose information to veterans. In 

theory, the technical work of this program could be used to support dose reconstructions for all employees 

of DOE, DOE contractors, or subcontractors employed at the PPG from 1946 through 1962. Since the 

veterans and members of the proposed class worked in the same locations or close proximity, they were 

subject to similar exposures. Therefore, the models developed for determining dose to veterans could be 

used for the class members. 

However, in 2003, the National Research Council (NRC) reviewed the NTPR program, issuing a report, "A 

Review of the Dose Reconstruction Program of the Defense Threat Reduction Agency" (NRC 2003). The 

review was prompted by a GAO report to Congress (2000) and examined the methods of the program and a 

random sample of completed dose reconstructions from the program to determine: 

•	 Whether or not the reconstruction of sample doses is accurate. 

•	 Whether or not the reconstructed doses are accurately reported. 

•	 Whether or not the assumptions made regarding radiation exposure based on sampled doses are 

credible. 

•	 Whether or not the data from nuclear tests used as a part of the reconstruction of sampled doses are 

accurate. 

The final report outlined several conclusions and recommended improvements relating to various aspects of 

the NTPR dose reconstruction process. 

NIOSH has examined the models used for the NTPR program, conclusions and recommendations by the 

NRC (NRC 2003), and DTRA’s corrective action plan (DOD 2004). The technical issues associated with 

internal and external exposures identified by the NRC were evaluated to determine whether the data or 

technical products of the NTPR program could be used to support dose reconstructions for the EEOICPA 

claims and whether the issues identified by the NRC can be resolved in a timely manner. 

Internal Dose Issues 

The internal dose reconstruction process established by DTRA starts by determining the activity ratio of 

hundreds of radionuclides produced by the weapon detonation. Since the time of the detonation is well 

documented, the decay of these radionuclides and the subsequent affect of that decay on the activity ratio 

are readily determined. DTRA assumes that the radionuclides are well mixed in the cloud produced by the 

detonation and subsequently, that the fallout is well mixed. This information is used to determine the 

radiation level per unit ground contamination. With that determination, and the calculation of a 

resuspension factor, the integrated airborne exposure is related to the external radiation exposure. 

The NRC review raised a number of issues associated with the methods used by DTRA to estimate 

inhalation dose. They summarized these issues in two tables. One table identified issues that potentially 

11 of 38 
overestimated internal doses. These issues were not evaluated in this SEC evaluation. The second table 

identified issues that potentially underestimated the inhalation dose. That table is reproduced below. The 

table number is the number in the NRC report. 

TABLE V.C.7 Summary of Assumptions Used to Estimate Inhalation Doses in NTPR Program That Have 

Substantial Uncertainty That Is Not Taken into Account or Should Tend to Result in Underestimates of 

Dose 

Dose coefficients (organ-specific equivalent doses per unit activity of radionuclides inhaled) 

•	 Uncertainties in dose coefficients due to uncertainties in dosimetric and biokinetic models are not 

taken into account. 

•	 Uncertainty in dose coefficients for alpha-emitting radionuclides due to uncertainty in biological 

effectiveness of alpha particles is not taken into account. 

•	 Dose coefficients for organs of GI tract from inhalation of plutonium may be underestimated when 

inhaled materials are respirable (AMAD, 1 μm). 

Methods used to estimate inhalation exposures (intakes of radionuclides in air) 

•	 Sources of error and uncertainty in methods of estimating radionuclide concentrations in deposited 

fallout based on measured external photon exposures have not been evaluated, and reliability of 

methods is unknown. The assumption of no fractionation (except for removal of noble gases) should 

result in substantial underestimates of concentrations of refractory radionuclides (such as 

plutonium), and the method of calculating external exposure rates per unit concentration of 

radionuclides on a surface probably is not valid for fallout deposited on ships in Pacific and should 

result in underestimates of concentrations in these cases. 

•	 Resuspension factor used to estimate radionuclide concentrations in descending fallout may result in 

underestimates of exposure when exposure did not occur during entire period of fallout. 

•	 Presence of fallout deposited more than a few months before exposure usually is ignored, especially 

late in period of atomic testing at NTS, when buildup of plutonium and longer-lived fission products 

from many prior shots was extensive. 

•	 Effect of blast wave from detonations at NTS on resuspension of substantial fraction of previously 

deposited fallout over large areas generally is ignored. 

•	 In some dose reconstructions for veterans who filed claim for compensation for cancer in internal 

organs and received substantial external dose, inhalation dose of zero was assigned even though 

inhalation exposure almost certainly occurred. 

•	 Resuspension factors applied to fallout deposited on ships in Pacific, especially below decks, may be 

too low. 

•	 Inhalation dose during time spent indoors on residence islands in Pacific is assumed to be zero; some 

inhalation doses below decks on ships also may be underestimated. 

The NRC concluded generally that the methods used in the NTPR program to estimate inhalation doses to 

atomic veterans do not consistently provide credible upper bounds. 

Most of the issues dealing with uncertainty are similar to issues NIOSH has already or is currently dealing 

with in the EEOICPA program. Of the issues identified by the NRC, NIOSH considers the following issue 

12 of 38 
most significant with respect to the feasibility of dose reconstruction for non-military personnel under 

EEOICPA: 

“Sources of error and uncertainty in methods of estimating radionuclide concentrations in deposited fallout 

based on measured external photon exposures have not been evaluated, and reliability of methods is 

unknown. The assumption of no fractionation (except for removal of noble gases) should result in 

substantial underestimates of concentrations of refractory radionuclides (such as plutonium).” 

DTRA and the Veterans Administration, with the support of the National Council on Radiation Protection, 

issued a report to Congress dated June 3, 2004 (DOD 2004) that identified a plan of action to correct the 

deficiencies identified by the NRC. The corrective actions identified for this issue included: potential 

modification of existing models; developing new models; and review by the Veterans Advisory Board on 

Dose Reconstruction. In the report, the plan indicated that this issue would be resolved within two years 

(i.e., June 2006) following submission of the report to Congress. 

In order for NIOSH to consider using the DTRA model for inhalation dose, the model must be able to 

establish credible upper bounds. Therefore, the issues identified by the NRC that question the ability to 

establish upper bounds would have to be resolved and the model would have to be validated, as 

recommended by the NRC. 

External Dose Issues 

The NTPR program primarily uses film badge monitoring data or radiation surveys with field instruments to 

determine external dose. If the person wore a film badge and the data could be located, the external gamma 

dose is generally based on those data. If no acceptable film badge data are available or if the film badge 

data do not cover all potential exposures, the external dose for these exposures are based on a “scientific” 

dose reconstruction that relies on survey data. 

The NRC review identified the following issues associated with the external dose reconstructions performed 

by NTPR: 

1) Although the methods used to estimate average doses to participants in various units are generally valid, 

many participants did not wear film badges all the times that they might have been exposed, so 

individual doses are often highly uncertain. 

2) Upper bounds of doses from external exposure to gamma radiation are often underestimated because of 

questionable assumptions about a person’s locations and durations of exposure. 

3) Skin and eye doses from exposure to beta particles do not always seem to be credible upper bounds, and 

skin doses from radioactive particles on the skin do not seem to have been taken into account. 

4) Upper bounds of doses from external exposure to neutrons are always underestimated by a factor of 

about 3–5, but few participants received much neutron exposure. 

The issues identified above are similar to issues that NIOSH has dealt with in the EEOICPA dose 

reconstruction process. NIOSH expects it could apply uncertainty factors to ensure a reasonable estimate of 

the external dose. In addition, the dose could be bounded by making claimant favorable assumptions to 

overcome data gaps. For example, when locations of employees are not clear the dose reconstructor could 

assign the employee the dose from the highest exposed group. 

Conclusion 

13 of 38 
 

Based on issues identified by the NRC that questioned the ability to establish an upper bound dose 

reconstruction, NIOSH has determined that the DTRA dose reconstruction approach could not be used at 

this time for completing dose reconstructions for the proposed class. Although the DTRA models might 

support the ability to estimate inhalation doses in the future, it is not certain that the issues identified by the 

NRC will be resolved in a reasonable period of time to support dose reconstruction for EEOICPA claims. 

7.2 Internal Radiation Exposure 

The principal potential source of internal radiation doses for members of the class would have been 

inhalation or ingestion due to contamination caused by the fallout from the nuclear detonations. The fallout 

patterns were part of the scientific investigations conducted as part of the testing program and were well 

investigated and documented in multiple reports, including those of Program 40, the PHS offsite monitoring 

program, the Radsafe organization, the Armed Forces Special Weapons Project, and the Scientific Task 

Group. 

It has been estimated that as much as 80 percent of the radioactive debris from a land surface burst falls out 

within the first day following the detonation. Detonations on the surface of seawater generate particles 

consisting mainly of salt and water drops that are smaller and lighter than the fallout particles from a landsurface detonation and as such, water bursts produce less early fallout. The initial radiation of an underwater 

detonation is absorbed by the large quantities of water surrounding the detonation point. The intense heat 

vaporizes the water and forms a bubble beneath the surface that expands as the energy works against the 

mass of water. The expansion continues until the energy is expended, at which point the bubble begins to 

collapse as it rises toward the surface. Depending on the depth of the burst and the size of the bubble, it may 

break the surface of the water near its fully expanded size or smaller. Some radioactive products are vented 

into the air as the bubble breaks the surface, but most of the device debris remains trapped in the volume of 

water that collapses on the bubble (the radioactive pool). 

The water-surface detonations at Enewetak and Bikini atolls, being mostly over relatively shallow lagoon 

waters (barge shots) or on the very little dry land probably formed a complex combination of land-surface 

and water particle size characteristics. 

Fallout associated with some of the detonations, both on the land surface and in the water, was a potential 

source of internal exposure. The possibility existed for inhalation and ingestion of radiological particles 

during a fallout event as well as exposure to re-suspended fallout remnants at some later date. Radiological 

particles on the land surface could potentially have been disturbed and re-suspended by wind, personnel 

traffic through contamination areas, construction activities disturbing contaminated soil, or by 

decontamination efforts, and been inhaled or ingested by personnel operating in the contaminated areas. 

Inhalation 

As indicated in section 6.0, limited urinalysis was reportedly done for certain test shots or series, but 

NIOSH has been unable to obtain those records. Some air monitoring was performed, but the only data 

available are offsite monitoring data. No occupational air sampling data are available. Air monitoring was 

performed to address fallout patterns rather than occupational internal exposure. While there is an indication 

that some nasal smears were performed, no data are available to NIOSH at this time from these smears. No 

evidence has been located to indicate that any lung or whole body counting or personal air monitoring was 

done as a part of the radsafe operations or procedures for the PPG. 

Although it might be possible to calculate the maximum plausible radionuclide deposition from the 

detonations, because there are so many variables (e.g., size and type of bomb, detonation height, 

14 of 38 
geographical conditions, weather conditions, etc.), each test would have to be evaluated individually to 

determine the maximum exposed individual or group for that test. This would require access to potentially 

sensitive information specific to each nuclear device together with extensive information on employee 

locations and activities. NIOSH cannot determine on a timely basis, with respect to this petition evaluation, 

the feasibility of a source and process-based dose reconstruction effort. 

Therefore, based on the lack of any internal monitoring data or area monitoring data and due to the 

significant variability in parameters that would affect actual deposition of radionuclides, NIOSH has 

determined that it is not feasible to estimate inhalation-related radiation doses for the class of employees 

covered by this report. 

Ingestion 

Fallout and residual contamination from underwater detonations in the lagoon waters would have been a 

potential source of internal exposure as the lagoon was both a water source and location of recreational 

swimming for personnel between shots. Generally, the circulation pattern of a lagoon is more restricted than 

the ocean. The northeast winds move the surface waters from east to west and in so doing there is upwelling 

on the east side of the lagoon to replace the westward flowing surface water. A circulation pattern is 

established in which surface water moves westward and then sinks, and the bottom waters move eastward 

and up-well. 

As has been noted earlier in this report, the lagoon waters were tested for contamination as both a water 

source and a recreation location. Beach swimming areas were closed on more than one occasion due to 

higher than acceptable levels of contamination. Reports from the Laboratory of Radiation Biology on beta 

activity at Rongelap Atoll indicate the ingestion of radiological material as part of the drinking water or 

recreational swimming would have been minimal (CASTLE 1954). In addition, the NRC reviewed various 

bounding ingestion scenarios when reviewing the NTPR program and came to the conclusion that doses to 

specific organs and tissues due to ingestion of radionuclides probably were low, compared with doses from 

external exposure, except in rare cases. 

NIOSH has not considered ingestion of potentially contaminated local foodstuffs. The practice of eating 

locally grown produce or seafood was prohibited by regulation and there has been no claim of ingestion of 

such by the petitioner, nor within any documentation received to date. 

As indicated in section 5.0, data may be available from the University of Washington, School of Fisheries 

that would support determining potential ingestion dose. However, at this time, no internal monitoring data 

that would support estimations of ingestion dose have been located. Since there is a lack of sufficient 

information to estimate inhalation-related doses to complete dose reconstructions for this class of 

employees, NIOSH has not completed evaluating the sufficiency of ingestion monitoring data. 

7.2 External Radiation Exposure 

External radiation exposure was the primary radiological concern for the planners and management of the 

nuclear atmospheric test operations in the PPG. The potential existed for external radiation exposure from 

fallout, the activation of debris (i.e. photo tower steel), contamination and immersion. The external exposure 

was monitored primarily through the use of film badges and radiation monitoring equipment. 

As discussed in the subsections of Section 6.0, specific to each test series, a film badge program was used to 

maintain exposure information on personnel living and operating in the PPG during the operations. 

Beginning with REDWING, film badges were issued to all individuals upon their arrival at the PPG to 

15 of 38 
determine gamma radiation exposure (S-56/239 p. 95). The configuration of the film badges would require 

the application of models to derive associated upper limit beta exposure estimates, as the badges would have 

shielded out significant amounts of beta radiation. In addition to the film badges, self-reading pocket 

dosimeters were issued for entrance to RADEX areas. The summary exposure data on individuals is 

available for this evaluation. Monitoring was performed for work parties entering radiological exclusion 

(RADEX) areas, with clearly specified stay times and dose limits. 

Based on the available data, NIOSH can utilize the film badge monitoring data or radiation surveys with 

field instruments to determine external dose. If the person wore a film badge and the data could be located, 

the external dose can be based on this data with correction factors applied for beta dose and uncertainty. If 

no acceptable film badge data are available, maximum credible exposure scenarios could be developed for 

individuals given the roles, responsibilities, and location associated with the task unit they were assigned to 

and exposure rate information for various work assignments. Again, correction factors for beta dose and 

uncertainty would be applied, as necessary. 

Neutrons 

The highest potential source of neutron exposure would have been the detonation events and accessing the 

detonation locations for recovery of monitoring equipment. Neutron exposure to personnel should not have 

been substantial during the period covered by this evaluation. This conclusion is consistent with that of the 

NRC. Personnel were evacuated beyond the range of both blast effects and neutron exposure from the 

detonations. Access controls were implemented for the detonation sites following the detonations as 

discussed in section 6.0 of this report. No neutron monitoring data were located, but since internal doses 

cannot be estimated to complete dose reconstructions for this class of employees, NIOSH did not complete 

an evaluation of the feasibility of estimating neutron doses. 

7.3 Occupational Medical Exposures 

Occupational medical exposures to X-rays, when such screening X-rays are a condition of employment, are 

also included in EEOICPA dose reconstructions. It is not clear during the proposed class time period 

whether individuals at the PPG site were required to have pre-employment, annual, and termination chest 

X-ray examinations. However, NIOSH could make claimant-favorable assumptions, as needed, on the 

frequency requirements of occupational medical X-rays and the type of X-ray equipment that may have 

been used. 

In addition, NIOSH has issued a Technical Information Bulletin (TIB), ORAU-OTIB-0006, Dose 

Reconstruction from Occupationally Related Diagnostic X-ray Procedures that can be used to assign dose 

from these procedures. Therefore, NIOSH concludes it is feasible to determine the maximum potential 

occupational medical exposures. 

7.4 Summary of Feasibility Findings 

This report evaluated the feasibility of completing dose reconstructions for all employees of DOE, DOE 

contractors, or subcontractors employed at the PPG from 1946 through 1962. NIOSH finds that the external 

monitoring records and operational histories available are sufficient to complete external dose 

reconstructions for these employees, with the exception of neutron exposure, which was not fully evaluated. 

Existing NIOSH procedures could be used to estimate possible occupational medical exposures. However, 

NIOSH lacks access to source term data, bioassay data or internal monitoring data to estimate internal doses 

associated with potential inhalation of radionuclides. Methods used by the NTPR program for military 

employees cannot be considered for application to dose reconstructions under EEOICPA until issues 

16 of 38 
identified by the NRC are resolved. Hence, NIOSH finds that it is not feasible to estimate with sufficient 

accuracy internal radiation doses for the class of employees defined in this report. 

The table below summarizes the results of the feasibility findings for each exposure source: 

TABLE 7.3.1 FEASIBILITY FINDINGS 

Source of Exposure Maximum Exposure can be 

determined 

Maximum Exposure cannot be 

determined 

Internal X 

- Ingestion Not evaluated 

- Inhalation X 

External X 

- Gamma X 

- Beta X 

- Neutron Not evaluated 

Occupational Medical X-ray X 

8.0 Evaluation of Health Endangerment 

The health endangerment determination for the class of employees covered by this evaluation report is 

governed by EEOICPA and 42 C.F.R. Pt. 83.13(c)(3). Under these requirements, if it is not feasible to 

estimate with sufficient accuracy radiation doses for members of the class, NIOSH must also make a 

determination whether or not there is a reasonable likelihood that such radiation doses may have endangered 

the health of members of the class. The regulation requires NIOSH to assume that any duration of 

unprotected exposure may have endangered the health of members of a class when it has been established 

that the class may have been exposed to radiation during a discrete incident likely to have involved levels of 

exposure similarly high to those occurring during nuclear criticality incidents. 

If the occurrence of such an exceptionally high level exposure has not been established, then NIOSH is 

required to specify that health was endangered for those workers who were employed for a number of work 

days aggregating at least 250 work days within the parameters established for the class or in combination 

with work days within the parameters established for one or more other classes of employees in the SEC. 

NIOSH has determined that it is not feasible to estimate with sufficient accuracy radiation doses from 

potential internal exposures. Internal doses from these exposures may have endangered the health of some 

members of the class, based on the facts that there was likely to have been some inhalation exposure to 

plutonium and other alpha-emitting radionuclides and the lack of reliable information to establish plausible 

maximum limits to this exposure. 

The NIOSH evaluation did not identify any evidence from the petitioners or from other resources that would 

establish that the class was exposed to radiation during a discrete incident or similar conditions resulting 

from the failure of radiation exposure controls and likely to have produced levels of exposure similarly high 

to those occurring during nuclear criticality incidents. Although the testing program involved controlled 

nuclear criticality events, NIOSH is not aware of any report of personnel exposure to exceptionally high 

levels of radiation, comparable to that resulting from nuclear criticality incidents, during any of the nuclear 

atmospheric test series at the PPG. If such exposures occurred, it is almost certain they would have been 

documented, given the highly organized radsafe operations and given the careful monitoring of external 

radiation exposures. The evidence reviewed in this evaluation indicates that some workers in the class may 

17 of 38 
have accumulated substantial chronic exposures through episodic intake of radionuclides. Consequently, 

NIOSH is specifying that health was endangered for those workers covered by this evaluation who were 

employed for a number of work days aggregating at least 250 work days within the parameters established 

for this class or in combination with work days within the parameters established for one or more other 

classes of employees in the SEC. 

9.0 Proposed Class Definition 

This evaluation defines a single class of employees for which NIOSH cannot estimate radiation doses with 

sufficient accuracy and whose health may have been endangered by such radiation doses. This class 

includes all employees of DOE, DOE contractors, or subcontractors employed at the PPG from 1946 

through 1962 for a number of work days aggregating at least 250 work days occurring either solely under 

this employment or in combination with work days within the parameters (excluding aggregate work day 

requirements) established for other classes of employees included in the SEC. 

18 of 38 
10.0 References 

ALO 58-2 

Office of Test Operations Albuquerque Operations; “Report of the Manager; Operation Hardtack, Phase I” 

CASTLE 1954 

Defense Atomic Support Agency; “Operation Castle, Radiological Safety, Final Report, Volume 1, 

Extracted Version,” 1954 

DNA 6032F 

Defense Nuclear Agency (DNA); “Operation Crossroads 1946” L. Berkhouse, J.H. Hallowell, F.W. 

McMullan, S.E. Davis, C.B. Jones, M.J. Osborne, F.R. Gladeck, E.J. Martin; DNA 6032F, 1 May 1984 

DNA 6033F 

Defense Nuclear Agency (DNA); “Operation Sandstone: 1948” L. Berkhouse, S.E. Davis, F.R. Gladeck, 

J.H. Hallowell , C.B. Jones, E.J. Martin, F.W. McMullan, M.J. Osborne, W.E. Rogers; DNA 6033F, 19 

December 1983 

DNA 6034F 

Defense Nuclear Agency (DNA); “Operation Greenhouse 1951” L. Berkhouse, S.E. Davis, F.R. Gladeck, 

J.H. Hallowell , C.B. Jones, E.J. Martin, F.W. McMullan, M.J. Osborne; DNA 6034F, 15 June 1983 

DNA 6035F 

Defense Nuclear Agency (DNA); “Castle Series, 1954” Edwin J. Martin, Richard H. Rowland; DNA 

6035F, 1 April 1982 

DNA 6036F 

Defense Nuclear Agency (DNA); “Operation Ivy: 1952” L. Berkhouse, S. Davis, M.K. Doyle, F.R. 

Gladeck, J.H. Hallowell, C.B. Jones, E.J. Martin, F.W. McMullan, R.H. Miller, M.J. Osborne, R. Pozega, 

W.E. Rogers, R.H. Rowland, C.F. Shelton; DNA 6036F, 1 December 1982 

DNA 6037F 

Defense Nuclear Agency (DNA); “Operation Redwing: 1956” L. Berkhouse, S. Bruce-Henderson, S. Davis, 

H. DeSantis, P. Dean, M.K. Doyle, F.R. Gladeck, J.H. Hallowell, E.J. Martin, F.W. McMullan, R.H. Miller, 

D.S. Patterson, W.E. Rogers, R.H. Rowland, C.F. Shelton, P. Sturman; DNA 6037F, 1 August 1982 

DNA 6038F 

Defense Nuclear Agency (DNA); “Operation Hardtack I 1958” L. Berkhouse, F.S. Calhoun, F.R. Gladeck, 

K.G. Gould, J.H. Hallowell, E.J. Martin, F.W. McMullan, R.A. Miller, M.J. Osborn, C.F. Shelton; DNA 

6038F, 1 December, 1982 

DNA 6040F 

Defense Nuclear Agency (DNA); “Operation Dominic I-1962” L. Berkhouse, S.E. Davis, F.R. Gladeck, 

J.H. Hallowell, C.B. Jones, E.J. Martin, R.A. Miller, F.W. McMullan, M.J. Osborne; DNA 6040F, 1 

February 1983 

DNA 6041F 

Defense Nuclear Agency (DNA); Johnson, Abby A.; Goetz, Jerald L.; McRaney, William K.; “For the 

Record-A History of the Nuclear Test Personnel Review Program, 1978-1986” DNA 6041F, 1 August 

1986. 

19 of 38 
DNA JTF 

“Radiological Safety Final Report Operation Hardtack” Vol. II 

DOD 2004 

Department of Defense (DOD); “Radiation Dose Reconstruction Program of the Department of Defense 

Report to Congress” June 2004 

HAI 

Deines, Ann C.; Goldman, David I.; Harris, Ruth R.; Kells, Laura J.; “Marshall Islands Chronology 1944 to 

1990” 11 January 1990 

HPJa 

Simon, S.L., Robison, W.L.; “A Compilation of Nuclear Weapons Test Detonation Data for U.S. Pacific 

Ocean Tests” Health Physics 73(1):258-264;1997 

NVOO 209 

US DOE Nevada Operations Office; “United States Nuclear Tests July 1945 through September 1992” 

DOE/NV—209-REV 15, December 2000 

NRC 2003 

National Research Council, “A Review of the Dose Reconstruction Program of the Defense Threat 

Reduction Agency” 2003 

PHS 1958 

Public Health Service; “Report of the Public Health Service Off-Site Radiological Monitoring Data 

Operation Hardtack Phase I 1958” 

S-56/239 

Task Group 7.2 Joint Task Force Seven; “Commander Task Group 7.2 Joint Task Force Seven Final Report; 

Operation REDWING” 31 July 1956 

TG 7.1 

Task Group 7.1; “Operation HARDTACK April-October 1958: Report of the Commander Task Group 7.1” 

May 29, 1959 

TG 7.4 

Task Group 7.4 Enewetak, MI; “Operation HARDTACK Final Report” 1958 

TG 7.5 

Minkkinen, C., Schlacks, H.P., Goeke, R.H., Weaver, C.L, “Task Group 7.5 Radiological Safety Support 

Operation Hardtack, Phase I” OTO-58-3, April 1959 

TKBS-0008-02 

ORAU Team, Rollins, E.; “Technical Basis Document for the Nevada Test Site – Site Description” ORAUTKBS-0008-2, February 2, 2004 

UCRL-51612 

Lawrence Livermore Laboratory UC/Livermore; Noshkin, V.E.; Wong, K.M.; Eagle, R.J.; Gatrousis, C.; 

“Transuranics at Pacific Atolls I. Concentrations in the Waters at Enewetak and Bikini” June 26, 1974 

20 of 38 
UW 

Donaldson, L.R.; “Annual Report of the Laboratory of Radiation Biology, University of Washington, July 

1, 1959-June 30, 1960” July 12, 1960 

UW 40 

Project 40 Laboratory of Radiation Biology University of Washington; Donaldson, Lauren R., “Summary of 

Operational Phases for Project 40 of Operation Hardtack” March 20, 1958. 

WT 89 

Cooney, James P., Graves, Alvin C.;“Operation Greenhouse Scientific Director’s Report of Atomic Weapon 

Tests at Enewetak, 1951 Annex 9.3 Radiological Safety”; WT-89 July, 1951 

WT 1359 

“Report of the Commander, Task Group 7.1, Operation REDWING” August 1956 

21 of 38 
 

APPENDIX A 

The Pacific Proving Ground and Atmospheric Testing 

1.0 Introduction 

Between 1945 and 1962, the U.S. Atomic Energy Commission (AEC) conducted 235 atmospheric nuclear 

weapon tests at sites in the US and in the Pacific and Atlantic oceans. In the Pacific, 29 atolls and 5 islands 

spread over 770,000 mi2

 with a total land area of about 70 mi2 comprise the Marshall Islands. Enewetak 

Atoll, Bikini Atoll, Johnston Island and Christmas Island in the Marshall Islands together, are the AEC’s 

Enewetak Proving Ground, later known as the Pacific Proving Ground (PPG). 

FIGURE 1 THE PACIFIC PROVING GROUND 

2.0 Enewetak and Bikini Atolls 

Enewetak Atoll 

Enewetak Atoll is a coral cap set on truncated, submerged volcanic peaks that rise from the ocean floor. 

Coral and sand have gradually built up narrow islands into a ring-like formation with open ocean on the 

outside and a relatively sheltered lagoon on the inside. The atoll is an elliptical shaped collection of about 

47 coral islands strung along the reef and has a total land area of 2.75 mi2

 enclosing a lagoon 23 miles in 

diameter, and with three passages that permit access to the lagoon from the sea. 

Enewetak Island, the largest in the atoll, lies on the southeastern edge and is only 4 km long and 1 km wide. 

Northeast of Enewetak Island is Parry Island, which was the operational headquarters for many of the test 

22 of 38 
series. These two islands are immediately south and east of Deep Entrance and account for about 30 percent 

of the atoll’s land area. 

FIGURE 2 ENEWETAK ATOLL 

BIKINI ATOLL 

Bikini Atoll, similar to Enewetak Atoll, is a coral cap set on truncated, submerged volcanic peaks that rise 

from the ocean floor. It consists of 27 small islands that encircle a broad lagoon 25 miles long and 15 miles 

wide, with a maximum depth of about 200 feet. It has a total land area of 2.72 square miles. The land area is 

concentrated in the eastern islands, from Bikini to Eneu and the southern islands, from Enidrik to Aerokoj. 

At Bikini, ocean water flows in over northern and eastern reefs and flows out of the western portion of Eneu 

Channel. Water exchanges over the western reefs with the tides, ocean water flowing in and mixing with the 

flood and lagoon water flowing out with the ebb. The net rate of flushing of Bikini waters is such that one23 of 38 
half of the lagoon waters is replaced by ocean water in 22 days and the original volume will account for 

only 10 percent of the lagoon volume after 2-1/2 months (DNA 6032F) 

FIGURE 3 BIKINI ATOLL 

3.0 PACIFIC TEST SERIES 

All of the test series were conducted by organizations designated as Joint Task Force (JTF), made up of 

military personnel from the four services, federal civilian personnel, and contractor personnel. 

The CROSSROADS test series was conducted by JTF 1, SANDSTONE was conducted by JTF 7, GREENHOUSE 

by JTF 3, and IVY by JTF 132. Before IVY, each task force was deactivated after its series was finished. The 

AEC continued to develop weapons, but the continuity of testing operations in the Pacific and the various 

roles in those operations was broken after each series. The discontinuity of the planning and command 

organization potentially had a significant impact on the method of record keeping and retention of those 

records. The inefficiencies of establishing new task forces with each test series was recognized near the end 

of GREENHOUSE , but JTF 3 was considered too large and expensive for long-term operation. By CASTLE, 

JTF 7 was established and conducted CASTLE, REDWING, and HARDTACK I. 

24 of 38 
The JTFs were divided into functional and service branch-oriented task groups. The scientific task group 

was the center of the operations and primarily staffed the work parties responsible for the retrieval of 

experimental results from contaminated locations. 

For all of the test series following CROSSROADS, activity was necessary preceding the detonations to meet 

the requirements of the experimental programs because the islands of the atolls were not arranged in a 

pattern that facilitated the placement of instruments. Causeways were built, earth was moved, facilities were 

constructed, etc. In addition, the facilities had to be maintained between test series, including utilities, and 

base support elsewhere on the atolls. Construction to prepare for the various missions of the different test 

series was always a possibility. 

3.1 CROSSROADS, 1946 

Operation CROSSROADS was the first atmospheric nuclear weapon test series held in the Marshall Islands. 

The series consisted of two detonations, each with a yield of 23 KT. The devices used in the CROSSROADS 

tests were similar in design to the Trinity device and the weapon detonated over Nagasaki, Japan. 

TABLE 1 CROSSROAD DETONATIONS AT BIKINI ATOLL 

Name Date (1946) Type of Detonation 

ABLE 1 July Airburst at 520 feet 

BAKER 25 July Underwater at a depth of 90 feet 

The series was to study the effects of nuclear weapons on ships, equipment, and material. A target fleet of 

more than 90 vessels was assembled in Bikini Lagoon as a target. This target fleet consisted of older U.S. 

capital ships, three captured German and Japanese ships, surplus U.S. cruisers, destroyers and submarines, 

and a large number of auxiliary and amphibious vessels. Military equipment was arrayed on some of the 

ships as well as amphibious craft that were beached on Bikini Island. Technical experiments were also 

conducted to study nuclear weapon explosion phenomena. Some experiments included the use of live 

animals. 

The support fleet of more than 150 ships provided quarters, experimental stations, and workshops for most 

of the 42,000 men that conducted the tests. Additional personnel were located on nearby atolls such as 

Enewetak and Kwajalein. The islands of the Bikini Atoll were used primarily as recreation and 

instrumentation sites. 

Before the first test, all personnel were evacuated from the target fleet and Bikini Atoll. These men were 

placed on units of the support fleet, which sortied from Bikini Lagoon and took safe positions at least 10 

nmi (18.5 km) east of the atoll. In the ABLE test, the weapon was dropped from a B-29 and burst over the 

target fleet. In BAKER, the weapon was suspended beneath an auxiliary craft anchored in the midst of the 

target fleet. (DNA 6032F) 

Radiological safety plans to limit personnel exposure were approved in April of 1946 that emphasized 

detection and avoidance of radiation, and included the establishment of exclusion areas, operational limits, 

and contamination controls (including donning and doffing clothing upon egress from potentially 

contaminated areas). Systematic reconnaissance was to begin shortly after each detonation with aerial and 

surface surveys, including water samples, soil samples, and marine life samples. Radiation safety (radsafe) 

monitors were assigned to monitor and limit the radiation exposure of work parties. Over 225 monitors were 

used for each of the two CROSSROADS detonations. As a result of CROSSROADS, military leadership 

recognized the need for a substantial, qualified, military radsafe organization. The Operational Plan set the 

maximum allowable dose for exposure over a long period at 0.1 roentgens (R) per 24 hours. In addition, no 

25 of 38 
individual was allowed to have a total exposure of over 50 or 60 R in 2 weeks. If an individual received 10 

R in 1 day or 60 R in 2 weeks, he was to be withdrawn from active participation in the operation. Such 

action was never required. 

About 15 percent of the JTF 1 personnel were issued at least one of the 18,875 film-badge dosimeters 

during CROSSROADS. Approximately 6,596 personnel were on islands or ships that had no potential for 

radiation exposure. Personnel anticipated to be at greatest radiological risk were badged, and a percentage 

of each group working in less contaminated areas was badged. The maximum accumulated exposure 

recorded was 3.72 R. 

The table below, summarizing film badge readings (in roentgens) for July and August, (when the largest 

number of personnel was involved) comes from the Nuclear Test Personnel Review Program report on 

Operation Crossroads (DNA 6032F). 

TABLE 2 SUMMARY OF CROSSROADS FILM BADGE READINGS 

Total 

badges 

read 

Exposure Range (Gamma) 

0 R 0.001-0.1 R 0.101-1.0 R 1.001-10.0 R 

JULY 

(%) 

3,767 

(100) 

2,843 

(75) 

689 

(18) 

232 

(6) 

3 

(<0.1) 

AUGUST 

% 

6,664 

(100) 

3,947 

(59) 

2,139 

(32) 

570 

(9) 

8 

(0.1) 

Due to the presence of alpha emitters, including plutonium, a program to urine test personnel thought to 

have been exposed was implemented to determine whether any had taken these substances into their bodies. 

The water-testing laboratory on the ship Haven was converted for testing urine. By 15 August 1946, 2600 

samples had been tested. The men doing the work had to use instruments that were on hand and develop 

techniques as they worked. The widespread presence of radioactive material led to high background counts 

and made it difficult to determine whether an individual had low levels of alpha emitters in his urine (DNA 

6032 F). 

3.2 SANDSTONE, 1948 

Operation SANDSTONE was conducted at Enewetak in the spring of 1948 and consisted of three tower shots, 

all detonated at a height of 200 feet. It was the second test series carried out at the PPG and was primarily a 

scientific series conducted by the AEC as a proof-test of second generation nuclear devices. The Los 

Alamos National Laboratory (LANL) provided technical leadership for the test series with the military 

providing supplies and support. 

The designation of the organization conducting the operation was JTF 7 and like JTF 1 it was military in 

form but consisted of military, civil service, and contractor personnel. JTF 7 was activated in October 1947. 

TABLE 3 SANDSTONE DETONATIONS AT ENEWETAK ATOLL 

Name Date (1948) Type of Detonation 

X-RAY 15 April Tower 

YOKE 1 May Tower 

ZEBRA 15 May Tower 

26 of 38 
 

The radiation safety plans for SANDSTONE established an organization to provide radiation safety (radsafe) 

expertise and services to commanders of the separate components of the task force, who were responsible 

for personnel safety within their commands. Personnel were trained in radiological safety. Standards 

governing permissible exposure were established. The permissible radiological exposure was established at 

0.1 roentgen (R) per 24-hour period and a maximum exposure of 3 R for certain approved specific missions. 

Film badges were issued to persons deemed likely3

 to be exposed to radiation, as well as a group, 

representative of the task force. An extensive weather forecasting group was established to predict wind 

directions and areas of potential fallout. Personnel were evacuated from danger areas before each 

detonation. Reentry to radioactive areas was restricted to personnel required to retrieve important data, and 

their radiation exposures were monitored. 

For SANDSTONE, cloud debris was collected by eight unmanned B-17 drone aircraft. The drones picked up 

significant amounts of radioactive material on their surfaces, posing potential radiation exposure to ground 

crews involved in decontamination. Samples collected were highly radioactive and required special 

handling as they were taken from the aircraft and prepared for shipment to laboratories for analysis. 

3.3 GREENHOUSE, 1951 

Operation GREENHOUSE was conducted during April and May of 1951, on the northeastern islands of the 

Enewetak Atoll. The test was conducted by Joint Task Force 3 (JTF3), made up of DOD and AEC 

personnel. Task force personnel were stationed either on the southern islands of Enewetak, on ships, or at 

Kwajalein Atoll depending on their mission. 

The test series consisted of four tower shots, two at 200 feet and two at 300 feet. These detonations resulted 

in significant downwind fallout. (DNA 6034F) The purpose of the four GREENHOUSE tests was to continue 

development of nuclear weapons and the development of thermonuclear weapons. 

TABLE 4 GREENHOUSE DETONATIONS AT ENEWETAK ATOLL 

Name Local time Date (1951) Type of Detonation 

DOG 0634 8 April Tower – 300 ft 

EASY 0627 21 April Tower – 300 ft 

GEORGE 0930 9 May Tower – 200 ft 

ITEM 0617 25 May Tower – 200 ft 

Radiological Safety regulations were issued by the Commander Joint Task Force 3 (CJTF 3). A maximum 

permissible exposure level was set at 0.1 R per day (0.7 R per week), not to exceed a total of 3.9 R for 13 

weeks. CJTF 3 could authorize a total exposure of up to 3 R on any one day in specific cases. When this 

authorization was made, exposed individuals were prohibited from further exposure to more than 0.1 R per 

day during the remainder of the operation. (DNA 6034F) 

For GREENHOUSE a "radiation area" was defined as any area where the level of radioactivity consistently 

exceeded 0.005 R per 24 hours. In addition, all radiation areas were routinely monitored at intervals 

prescribed by the commanding officer on recommendation of the radsafe staff. 

 As part of the radsafe program, film badges were issued to individuals who possibly could have been 

exposed to radiation while performing their duties such as visiting any of the islands after the shots, boat 

3

 For examples of how decisions concerning who was to be badged were made, see the checkpoint monitors instructions, i.e. the 

24 April 1948 instructions for the checkpoint on Enjebi, which instructed that any personnel expected to come closer than 550 

yards to surface zero were to be issued film badges (DNA 6033F p. 60). 

27 of 38 
 

pool crews, radiation monitors, aircrews, aircraft decontamination personnel, and runway crash crews. In 

addition, over 75 film badges for each test were distributed among the six participating ships, to be worn 

from the day of the test and 7 days thereafter. Of the approximately 9,350 men in the test area during all or 

part of the testing operations, 2,416 were badged one or more times. Film badges for personnel entering 

radioactive areas normally were issued and turned in daily. Boat pool, air crew, and ship badges generally 

were issued for a week. 

The overall average exposure recorded by these badges was less than 0.5 R. A number of individuals, 

however, had recorded exposures between 5 and 8 R. Some individuals with these higher exposures were 

affiliated with the AEC and some were involved with the Air Force long-range radioactive cloud-tracking 

and sampling program. Of 551 non-military participants, 345 had badge readings less than 1 R, 82 had 

readings from 1 to 3 R, and 34 had readings over 3 R with a high reading of 8.575 R. (DNA 6034F) 

Fallout occurred on the islands of Japtan, Parry, and Enewetak and the six task force ships after three of the 

four shots in this series. The fallout from the first two shots was heaviest on Japtan and lightest on 

Enewetak. Enewetak was a base island where personnel from JTF 3 lived throughout the series. Japtan was 

an island used for recreation, but it also had an Army communication station and a Navy medical research 

unit. The fallout from shot ITEM, the last shot in this series, was much heavier than the first two. Enewetak 

Island received heavier fallout from ITEM than Japtan and Parry. Personnel who remained on Enewetak 

Island for 4 days after ITEM received over 2.45 R. Those who remained for 14 days received over 2.8 R, 

however, most people departed the test area within a week after the shot. 

3.4 IVY, 1952 

Test series IVY was held at Enewetak Atoll during November of 1952 and consisted of two detonations, 

MIKE and KING. MIKE was an experimental device and produced the first thermonuclear detonation. KING 

was a stockpile weapon, modified to produce a large yield. It was dropped from a B-36 bomber. The energy 

from KING was generated by the fission of plutonium atoms. These were the largest nuclear explosions to 

that time. 

TABLE 5 IVY DETONATIONS AT ENEWETAK ATOLL 

Name Local time Date (1952) Type of Detonation 

MIKE 0714 1 Nov Surface; Eluklab Island 

KING 1130 16 Nov Airburst at 1,480 feet, off 

Runit Island 

Joint Task Force 132 (JTF 132) was the organization that conducted the IVY test series. Approximately 

2,300 civilians were part of the task force, most of which operated from Enewetak Atoll and the task force 

ships based there. 

Fallout occurred on JTF 132 ships and on Parry and Enewetak islands following both of the test detonations. 

Exposure, calculated by the Nuclear Test Personnel Review based on data collected aboard three ships 

anchored near the islands indicates a maximum cumulative personnel exposure due to this fallout at 0.25 to 

0.53 R for personnel continuously at Enewetak Atoll from 4 November to 31 December 1952. This 

calculation ignores weathering and shielding. 

IVY posed some unique problems to JTF132 staff and the AEC because of the predicted large size of the 

detonations. The MIKE shot was expected to produce a yield far surpassing that of any earlier test, and the 

concern was that the radioactive fallout would be a more serious problem both to participants and off-island 

inhabitants. There was concern that a device detonated in the atmosphere might significantly contaminate 

the lagoon and restrict its use by fleet ships. The shot would be detonated without benefit of near-shot-time, 

28 of 38 
 

shot-island weather data because of personnel evacuation requirements. Thus, during the 5 hours between 

evacuation and detonation, unpredicted shifts in forecast favorable winds could increase the potential of 

exposing the fleet to fallout. 

Two other distinct radiation concerns existed: 

•	 Initial radiations emitted by the detonation and thermal effects. This was controlled by 

completely evacuating personnel to safe distances from the atoll for shot MIKE 

•	 Residual radiation near the detonation site that posed a problem for recovery of scientific 

instrumentation and other work. Exposure was controlled by a more intensive radsafe 

monitoring and control effort for those participating in areas close to the detonation locations 

and by a much enlarged program for protection of personnel remote from ground zero 

The task force commander published Operation Order 1-52 which, among other responsibilities, required 

the task group commanders to establish lists of all personnel required by the nature of their duties to use 

dosimeters, to require physical examinations of civilian personnel who had to handle radioactive material, 

or who had to be in the forward areas (i.e. any island or lagoon area north of Parry Island) during or after a 

detonation and of all radiological monitors. 

Task force personnel exposed to nuclear radiation during the IVY test series were primarily involved in 

operations such as radioactive cloud sampling and data recovery where exposures were expected to occur. 

Only low-level widespread exposure of support personnel appears to have occurred. Very few men 

exceeded the task force maximum permissible exposure of 3.9 R. Those that significantly exceeded this 

limit were involved in two aircraft incidents. Nearly 90 percent of the recorded IVY exposures were less 

than 1 R. 

3.5 CASTLE , 1954 

CASTLE was a six-detonation nuclear weapon test series in the spring of 1954. The purpose was to test large 

yield thermonuclear devices. 

TABLE 6 CASTLE DETONATIONS 

Name Date (1954) Type of Detonation 

BRAVO 1 March Surface; Bikini 

ROMEO 27 March Barge; Bikini 

KOON 7 April Surface; Bikini 

UNION 26 April Barge; Bikini 

YANKEE 5 May Barge; Bikini 

NECTAR 14 May Barge; Enewetak 

CASTLE was conducted by JTF 7. Tests were carried out in conjunction with each of the detonations to 

measure power and efficiency of the devices and to attempt to gauge the military effects of the explosions. 

BRAVO event was the largest device ever detonated in atmospheric nuclear testing by the U.S. Government 

and released large amounts of fallout over a much larger area than anticipated. This resulted in the 

contamination and exposure of multiple individuals living on distant atolls, stationed at the PPG and 

participating in the test series, and the personnel of a Japanese fishing vessel known as the Lucky Dragon. 

A limited number of JTF 7 personnel received radiation exposures considerably in excess of the initially 

established CASTLE maximum permissible exposure (MPE). This operational limit was 3.9 R (gamma) 

29 of 38 
 

within any 13 week period of the operation. Three military personnel had heavily exposed badges with 

readings from 85 to 95 R. As a result of BRAVO, 21 task force members received beta burns. 

The other five CASTLE detonations did not produce significant, unexpected personnel radiation exposures. 

The radiation exposure for JTF 7 personnel at CASTLE averaged about 1.7 R. 

3.6 REDWING, 1956 

REDWING was a 17-detonation nuclear atmospheric test series conducted in May, June, and July of 1956. 

Detonations were conducted at both Enewetak and Bikini atolls. Enewetak served as a base of operations 

and was where smaller-yield devices were tested. Bikini was the advance camp where the larger-yield 

devices were tested. 

TABLE 7 REDWING DETONATIONS 

Name Date (1956) Type of Detonation 

LACROSSE 5 May Surface; Enewetak 

CHEROKEE 21 May Airdrop; Bikini 

ZUNI 28 May Surface; Bikini 

YUMA 28 May Tower; Enewetak 

ERIE 31 May Tower; Enewetak 

SEMINOLE 6 June Surface; Enewetak 

FLATHEAD 12 June Barge; Bikini 

BLACKFOOT 12 June Tower; Enewetak 

KICKAPOO 14 June Tower; Enewetak 

OSAGE 16 June Airdrop; Enewetak 

INCA 22 June Tower; Enewetak 

DAKOTA 26 June Barge; Bikini 

MOHAWK 3 July Tower; Enewetak 

APACHE 9 July Barge; Enewetak 

NAVAHO 11 July Barge; Bikini 

TEWA 21 July Barge; Bikini 

HURON 22 July Barge; Enewetak 

The REDWING series’ primary objective was to test high-yield thermonuclear devices that could not be tested 

in Nevada. The development and testing of these fusion devices began in 1950 and had advanced to the 

stage that one of these, CHEROKEE, was dropped from a B-52 bomber during REDWING. CHEROKEE, 

although of some scientific interest (all of the other shots tested new weapon developments), was more of a 

political demonstration to the world of the U.S. ability to deliver these weapons. The drop, as well as 

detonation LACROSSE, was witnessed by a group of 15 U.S. newsmen, the first such group invited to view a 

Pacific nuclear test since 1946. In addition to the press observers, 17 invited civil defense officials viewed 

the detonations. 

REDWING was conducted by JTF 7, the same task organization that conducted CASTLE series. JTF 7 was 

established as a permanent organization in 1953 as the successor to JTF 132, which had conducted the IVY 

test series in 1952, and existed through 1958 when it conducted HARDTACK I. The structure, roles, and 

responsibilities of the components of this and previous JTFs with respect to the mission, safety, and security 

are documented in several reports, directives, and procedures. Numerous technical experiments were carried 

out in conjunction with each of the 17 detonations to measure the yield and efficiency of the devices. JTF 7 

also attempted to gauge the military effects of the explosions. 

30 of 38 
 

 

Because of the isolation of the PPG, JTF 7 gave considerable attention to recreational activity for personnel. 

Enewetak Island had two movie theaters, a TV station, a hobby shop, a swimming pool and beach areas 

designated for swimming4, a skeet range, playing fields, basketball and handball courts, and a service club 

with snack bar, library, game room, and rooms for adult education classes and clubs. Competitive leagues 

were organized for many sports. (DNA 6037F) 

The operations ran smoothly except for two incidents. The airdropped demonstration test, CHEROKEE, was 

considerably off target; and the edge of the cloud from the last event fired at Bikini, TEWA, passed over 

Enewetak, causing fallout there. The missed airdrop caused no exposure of personnel to ionizing radiation 

as the entire Bikini Atoll had been evacuated, and the miss was in the direction of the open sea, but the 

TEWA fallout on the Enewetak base camp did lead to the exposure of the personnel there. The incident 

occurred toward the end of the series when some personnel had already returned to the United States, but 

the remaining Enewetak personnel received about an additional 1.5 R exposure from this incident. The 

overall average exposure for the series was approximately 1.7 R. The highest exposures were recorded by 

Air Force flight officers whose aircraft penetrated the nuclear clouds on scientific missions. (DNA 6037F) 

The emphasis on safety was apparent in early planning and stressed throughout REDWING. Radsafe planning 

proceeded with the concurrence of other agencies (i.e. Department of State for improved offsite monitoring) 

when required. The radsafe program for REDWING had two primary objectives: 1) the maintenance of 

personnel radiation exposure at the lowest possible level consistent with medical knowledge of radiation 

effects and the importance of the test series and 2) avoidance of inadvertent contamination of populated 

islands or transient shipping. These objectives were consistent with those of all the previous test series. 

The radsafe standard for maximum permissible exposure (MPE) was set at 3.9 R for the series. Film badges 

were provided for all5

 of the participating personnel. Persons likely to be exposed to radiation were often 

provided with additional badges for more complete recording of exposure. JTF 7 personnel were evacuated 

from danger areas to Navy vessels before each test and reentry to radioactive areas was restricted to the 

personnel required to retrieve important data. 

3.7 HARDTACK I, 1958 

HARDTACK was the operational designation for the U.S. atmospheric nuclear test series in the Pacific and in 

Nevada in 1958. HARDTACK I was conducted at the Pacific Proving Ground, and was a series in which 35 

nuclear devices were detonated6 in the spring and summer of 1958. 

TABLE 8 HARDTACK I DETONATIONS AT ENEWETAK ATOLL 

NAME Date (1958) Type of Detonation Location 

YUCCA 28 April Airburst; high 

altitude 

between Bikini and 

Enewetak 

CACTUS 6 May Surface Enewetak 

FIR 12 May Barge Bikini 

4

 As noted in the original petition, SEC00020, swimming in the lagoon was an internal exposure concern. The radsafe program 

routinely monitored the waters of the approved, designated swimming areas. One of the swimming areas was closed for several 

days following Bikini shots and was closed after NAVAJO for the rest of REDWING. Swimming was prohibited when contaminants 

were present at greater than 1x10-5 microcuries per millimeter (sic) depending on the age of the contaminants. (DNA 6037F p. 79) 5

 REDWING was the first test series with universal film badging, as opposed to badging those individuals expected to receive some 

level of radiation exposure. This may have been, to some degree, a reaction to BRAVO fallout from the CASTLE series. 6

 Of the 35 test shots, 22 were conducted at Enewetak, 10 were conducted at Bikini, 1 was between the two atolls, and two were 

over Johnston Island. (DNA 6038F) 

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BUTTERNUT 12 May Barge Enewetak 

KOA 13 May Surface Enewetak 

WAHOO 16 May Underwater In ocean between 

Bikini and Enewetak 

HOLLY 21 May Barge Enewetak 

NUTMEG 22 May Barge Bikini 

YELLOWWOOD 26 May Barge Enewetak 

MAGNOLIA 27 May Barge Enewetak 

TOBACCO 30 May Barge Enewetak 

SYCAMORE 31 May Barge Bikini 

ROSE 3 June Barge Enewetak 

UMBRELLA 9 June Underwater Enewetak 

MAPLE 11 June Barge Bikini 

ASPEN 15 June Barge Bikini 

WALNUT 15 June Barge Enewetak 

LINDEN 18 June Barge Enewetak 

REDWOOD 28 June Barge Bikini 

ELDER 28 June Barge Enewetak 

OAK 29 June Barge Enewetak 

HICKORY 29 June Barge Bikini 

SEQUIOA 2 July Barge Enewetak 

CEDAR 3 July Barge Bikini 

DOGWOOD 6 July Barge Enewetak 

POPLAR 12 July Barge Bikini 

SCAEVOLA 14 July Barge* Enewetak 

PISONIA 18 July Barge Enewetak 

JUNIPER 22 July Barge Bikini 

OLIVE 23 July Barge Enewetak 

PINE 27 July Barge Enewetak 

TEAK 31 July Airburst; high 

altitude 

Johnston Island 

QUINCE 6 August Surface* Enewetak 

ORANGE 11 August Airburst; high 

altitude 

Johnston Island 

FIG 18 August Surface Enewetak 

 *Were reported to be zero yield tests 

HARDTACK I had multiple purposes; to assist in the development of nuclear weapons, to improve the 

understanding of the effects of underwater explosions on Navy ships and materials, and to provide 

information on nuclear weapons in air and ballistic missile defense. Twenty-two detonations occurred at or 

near Enewetak Atoll during HARDTACK I, as shown in Table 6.1. The HARDTACK I atmospheric test shots 

consisted of the unconfined detonation of nuclear devices in the atmosphere, some placed on a platform or a 

barge on the surface, two flown high into the atmosphere by a rocket, and some detonated underwater. 

In planning the HARDTACK test series, emphasis on safety was apparent and stressed throughout the 

operation. Radiological safety was treated as a command responsibility. Each of the task groups was 

responsible for establishing self-sufficient radiological safety units to handle routine radiological safety 

matters and problems unique to the function of the task group itself. 

32 of 38 
 

Monitoring and administrative control systems were established to detect and measure radioactivity in the 

vicinity of the PPG for HARDTACK I. Radiological monitoring and sampling were conducted. Marine 

surveys were conducted to measure any increase in radioactivity in sea water and marine organisms due to 

HARDTACK I detonations. All atoll and lagoon areas at or near a detonation site were considered 

contaminated7 until cleared for operations by the Radiological Safety Office. Entry control procedures were 

managed by the Radiological Safety Office. Entry to and exit from RADEX areas was only through 

established checkpoints. RADEX areas were areas of surface radiological contamination or airborne 

radiological contamination designated following each detonation for the control of personnel entry and exit. 

Personnel were not permitted beyond a radsafe checkpoint without an access pass that stated the purpose 

and precise location of the entry. All vehicles used in RADEX areas were checked through established 

decontamination stations. 

A fallout prediction capability, the Fallout Prediction Unit, and the Fallout Plotting Center were established 

specifically for HARDTACK I, with fallout stations, monitors, and couriers, an extensive associated weather 

forecast capability, and weather monitoring stations established around the PPG to support both the forecast 

operations and the radiological monitoring objectives. Sweeps by U.S. Navy vessels both during and after 

the test series included taking continuous readings of radioactivity in surface water, sampling of water at 

various depths, making tows to gather plankton, and catching fish for analysis. Land and marine biological 

surveys were conducted, including water, plant, and animal samples. In addition, the operation plan directed 

task group commanders to establish radsafe units within the task groups with adequate special clothing and 

instrumentation. The task groups were to provide a roster of their personnel for film badge preparation. 

A film badge program was used to maintain complete exposure information on all JTF 7 personnel entering 

the PPG during the operation. Beginning with the previous test series, REDWING, everyone was badged with 

few exceptions. Beginning 1 April 1958, film badges were issued to all individuals upon their arrival at the 

PPG. Badges were required to be worn at all times and turned in upon recall, upon exit from any 

contaminated area, or upon departure from the PPG. The badge was a DuPont 559 film packet (502 and 834 

film components) dipped in ceresin wax and then packaged in a rigid polyvinyl chloride case to provide 

moisture protection. All exposed film badges were developed using the standard techniques employed at 

Los Alamos Scientific Laboratory (LASL). They were calibrated on a constant time, variable distance 

range, and the calibration curves were checked for accuracy approximately every 2 weeks. Density of the 

exposed film was read with the Eberline Film Badge Evaluation and Recording System, FS-3, in 

conjunction with an IBM-526 Summary Punch. 

Self-reading pocket dosimeters, Bendix Model 611, 1 to 5 R range, were also used to obtain quick 

information on the exposure of an individual while in a contaminated area. 

The operational procedures for HARDTACK I specified a MPE limit of 3.75 R (gamma) per consecutive 13­

week period with a maximum of 5 R for the operation, with exceptions for emergency and other tactical 

situations. The operation was defined as the period from 15 days before the first ready date to 15 days after 

the last shot. A special MPE of 10 R was authorized for crewmembers of air-sampling aircraft. In the event 

of operational error or emergency, an additional exposure of 10 R would be accepted. Any exposure in 

excess of 20 R total would be considered as an overexposure for aircrew samplers. Partway through the 

operation, sample-recovery personnel had their authorized exposure change from 5 R to 10 R. At the same 

time aircraft maintenance personnel had their maximum exposure raised from 5 R to 8 R. 

7

 RADEX areas were not strictly defined for alpha contamination. The general definition of full RADEX was an area of greater 

than 100mr/hr gamma including areas in excess of 10,000 cpm alpha (using a 55 cm2

 probe) and limited RADEX was an area of 

between 10 and 100 mr/hr gamma, including areas between 1,000 and 10,000 cpm alpha. 

33 of 38 
Water samples from swimming areas and from the lagoons, where water was distilled for ships, were 

periodically taken and tested for contamination. No significant radioactivity was found in any of the ships’ 

water samples but a swimming beach at Enewetak island was closed for one day because of fallout from an 

atmospheric test at Bikini Atoll designated FIR (May 12 ). Radiochemistry laboratory trailers were located 

on both Enewetak and Bikini atolls. These facilities did not perform detailed radiochemistry studies; they 

were for onsite support such as checking potable water and swimming areas to ensure task group personnel 

safety. 

Personnel decontamination was required when radiation levels exceeded 0.007 R/hr (beta plus gamma) or 

500 cpm (alpha) (55 cm2 probe) for outer clothing or 0.001 R/hr (gamma) or 100 cpm (alpha) (55 cm2 

probe) on skin or underclothing. All personnel returning from RADEX areas were monitored at the 

checkpoints. If contaminated, they were processed through the personnel decontamination station adjacent 

to the Radsafe Center. 

During the spring and summer of 1958, the Public Health Service (PHS) operated an “offsite” radiological 

safety program under an agreement with JTF 7. PHS Officers were stationed on each of the close-in 

populated atolls of Utirik, Ujelang, Rongelap and Wotho to secure data on radiation levels and collect 

environmental samples for analysis. In addition, data was obtained for Parry Island and Enewetak Island in 

the Enewetak Atoll. Parry Island was used as the joint task force headquarters as well as the headquarters 

and living area for the scientific groups. Enewetak Island was primarily covered with an airfield and its 

support buildings and equipment, including shops, warehouses, and barracks. Japtan, the third major island 

in the base area, was across the deep channel from Parry Island and was the site of a radio receiver station 

and was used as a recreational area. Gamma intensity readings were taken daily using a Radiation 

Detection Indication And Computation (RADIAC) meter AN/PDR 27F, calibrated against a standard 

consisting of 7 micrograms of radium. The weighted daily averages of readings for Parry Island are 

available from 5/06/58 to 7/31/58 (except for 7/12/58). Daily average readings for Enewetak Island are 

available from 5/19/58 to 7/31/58. 

Additionally, PHS carried out a fallout and rain sampling program. Precipitation was collected at six 

stations in and about the PPG, on Parry Island, Enewetak Island, Rongelap Island, Ujelang Island, Utirik 

Island and Wotho Island. The samples were collected in weekly composites, the precipitation falling in a 

collector funnel of 0.4 m2

 in area and retained in a carboy of approximately 19 liters volume. A summary of 

the collection and processing procedure for these samples is available in the Report of Public Heath Service 

Off-Site Radiological Monitoring Data (PHS 1958). 

Finally, PHS conducted a Marine Biology Survey of the PPG during HARDTACK I. Data is available listing 

the water sample point coordinates, the water sample readings in dpm (gross beta), the plankton readings in 

dpm/cc (gross beta), and the external gamma readings of the plankton samples, counted in August and 

September of 1958. 

3.8 DOMINIC I, 1962 

DOMINIC I was a series of 36 atmospheric nuclear weapon detonations held in the PPG area from April to 

November 1962. These detonations and the continental DOMINIC II tests were the last atmospheric nuclear 

weapon tests conducted by the United States. 

As in previous test series in the Pacific, a joint military and civilian organization conducted these tests, Joint 

Task Force Eight (JTF 8). 

TABLE 9 DOMINIC I DETONATIONS 

34 of 38 
Name Date (1962) Type 

ADOBE 25 April Airdrop; S of Christmas Island 

AZTEC 27 April Airdrop; S of Christmas Island 

ARKANSAS 2 May Airdrop; S of Christmas Island 

QUESTA 4 May Airdrop; S of Christmas Island 

FRIGATE BIRD 6 May Airburst; Polaris proof-test, in Christmas Island Danger Area 

YUKON 8 May Airdrop; S of Christmas Island 

MESILLA 9 May Airdrop; S of Christmas Island 

MUSKEGON 11 May Airdrop; S of Christmas Island 

SWORDFISH 11 May Underwater; ASROC proof-test, 370 nmi SW of San Diego 

ENCINO 12 May Airdrop; S of Christmas Island 

SWANEE 14 May Airdrop; S of Christmas Island 

CHETCO 19 May Airdrop; S of Christmas Island 

TANANA 25 May Airdrop; S of Christmas Island 

NAMBE 27 May Airdrop; S of Christmas Island 

ALMA 8 June Airdrop; S of Christmas Island 

TRUCKEE 9 June Airdrop; S of Christmas Island 

YESO 10 June Airdrop; S of Christmas Island 

HARLEM 12 June Airdrop; S of Christmas Island 

RINCONADA 15 June Airdrop; S of Christmas Island 

DULCE 17 June Airdrop; S of Christmas Island 

PETIT 19 June Airdrop; S of Christmas Island 

OTOWI 22 June Airdrop; S of Christmas Island 

BIGHORN 27 June Airdrop; S of Christmas Island 

BLUESTONE 30 June Airdrop; S of Christmas Island 

STARFISH 8 July Airburst; FISHBOWL shot, 400 km over Johnston Island 

SUNSET 10 July Airdrop; S of Christmas Island 

PAMLICO 11 July Airdrop; S of Christmas Island 

ANDROSCOGGIN 2 October Airdrop; Johnston Island Danger Area 

BUMPING 6 October Airdrop; Johnston Island Danger Area 

CHAMA 18 October Airdrop; Johnston Island Danger Area 

CHECKMATE 19 October Airburst; FISHBOWL shot, tens of km over Johnston Island 

BLUEGILL 25 October Airburst; FISHBOWL shot, tens of km over Johnston Island 

CALAMITY 27 October Airdrop; Johnston Island Danger Area 

HOUSATONIC 30 October Airdrop; Johnston Island Danger Area 

KINGFISH 1 November Airburst; FISHBOWL shot, tens of km over Johnston Island 

TIGHTROPE 3 November Airburst; FISHBOWL shot, tens of km over Johnston Island 

Most of the DOMINIC I test shots were airdrops, having been dropped from a B-52 bomber. Twenty-four of 

the airdrops took place from 25 April through 11 July over the ocean just south of Christmas Island. This 

island is located 1,200 nmi south of Honolulu. Five more airdrops were detonated in October over the open 

ocean in the vicinity of Johnston Island, 780 nmi west-southwest of Honolulu. These tests were conducted 

for the purpose of weapon development. Five high-altitude bursts (up to 250 miles) were lofted by rockets 

from Johnston Island and were for the purpose of studying the effects of nuclear detonations as defensive 

weapons against ballistic missiles. These detonations were designated the FISHBOWL events. In addition, the 

Navy conducted two nuclear tests in the open ocean, the first on 4 May about 435 nmi east of Christmas 

Island and the second on 11 May 370 nmi southwest of San Diego, California. The first, called FRIGATE 

BIRD, was a missile-launched airburst, a proof test of the Polaris weapon system, launched from the 

35 of 38 
 

submarine, USS Ethan Allen (SSBN-608). The second, called SWORDFISH, was the test of the Navy ASROC 

system, a rocket-launched antisubmarine nuclear depth charge. 

The Commander of JTF 8 (CJTF 8) was assigned overall responsibility for radiation safety. The Radsafe 

Branch, located organizationally in the Operations and Plans Office of Headquarters JTF 8, was responsible 

for overall control of monitoring and decontamination, issuing radsafe supplies and equipment, maintaining 

RADIAC instruments, procuring all film badges, developing and interpreting exposed badges, and 

maintaining cumulative radiation exposure records for everyone who was badged. These records were 

compiled and are supposed to exist in a document referred to as the Consolidated List of Exposures. This 

branch also managed an extensive offsite radiation surveillance network on 17 remote islands throughout 

the Pacific. Task groups, which were subordinate to JTF 8, had command responsibility for radiological 

safety within their organizations. 

Film badges were issued to everyone who was stationed on Christmas and Johnston islands and all Navy 

ships directly involved with the tests. Persons on remote islands monitoring for radiation or conducting 

experiments were not badged. Of the over 28,000 participants in DOMINIC I, over 25,000 were badged. 

Badges were issued for extended periods to ensure that all possible exposure was recorded. 

Because all but one of the shots (SWORDFISH), were airbursts or airdrops, there was little or no fallout 

problem and no residual radiation area around the surface zero. Although SWORDFISH produced no fallout, it 

did create a short-lived radioactive base surge and a pool of radioactive water around the detonation. The 

base surge dissipated in less than an hour, and the pool dissipated after a few days. 

In general, film badge readings were low. Only 842 (3 percent) of the 25,399 badged participants had an 

exposure greater than 0.5 R. Of these, 56 exposures were over 3.0 R. The established JTF 8 MPE was 3.0 R. 

Fifty-one military personnel over 3.0 R were associated with cloud sampling (crew, maintenance, sample 

removal, or decontamination) and were authorized an MPE of 20.0 R before the operation started. The 

highest total exposure recorded in this group was 17.682 R: this was also the highest for the entire 

operation. The Navy personnel recording over 3.0 R were on USS Sioux (ATF-75), which was involved in 

collecting samples of weapon debris from the radioactive pool of water created by the underwater 

SWORDFISH shot. This group was allowed an MPE of 7.0 R. 

Evidence exists that many of the badges worn by personnel during DOMINIC I were defectively sealed and 

recorded density changes due to moisture, light, and heat in addition to nuclear radiation. A 1979-1980 reevaluation of 1,349 DOMINIC I film badges showed that 45 percent exhibited some damage related to light, 

heat, and age due to defective wax seals. Environmental damage was observed on 98 percent of the badges, 

which had a developed density equivalent of over 0.4 R (gamma). 

One of the Thor rockets being launched at Johnston Island with a nuclear payload burned on the launch pad. 

The high explosives in the nuclear warhead detonated, spreading alpha contamination around the launch 

complex. It took several weeks to decontaminate and rebuild the launch complex. Stringent personnel safety 

measures were enforced during the cleanup. Reportedly, no one received significant contamination from 

this accident. (DNA 6040F) 

4.0 Nuclear tests and radiation exposures 

Nuclear testing by the U.S. consisted mostly of the unconfined detonation of nuclear devices in the 

atmosphere. Devices might be placed on a platform or a floating barge, placed atop a tower, supported by a 

balloon, dropped from an airplane, or flown on a rocket. Some were detonated underwater or buried in 

underground tunnels and shafts. 

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In theory, personnel could be exposed either by the initial radiation emitted at the time of explosion and for 

about 1 minute thereafter, or by the residual radiation emitted later. Initial radiation is part of the violent 

nuclear explosion process itself, and to be close enough for initial radiation exposure could place an 

observer within the area swept by lethal blast and thermal effects. 

The neutron component of initial radiation did indirectly contribute to the possibility of personnel exposure. 

Neutrons are emitted in large numbers by nuclear weapon detonations. Neutron activation works on sodium, 

silicon, calcium, manganese, and iron, as well as other common materials. The process affects the metal 

casing of the device, the test tower, and earth materials. Activation products thus formed are added to the 

inventory of the radioactive debris produced in the detonation process and could expose personnel in the 

vicinity of this residual radiation in the performance of their duties. 

The overall radioactivity of all the fission products formed decays at a rate that is closely approximated by a 

rule that states that for each sevenfold increase in time the intensity of the radiation will decrease by a factor 

of ten. Thus, a radiation rate of 1 R/hr at 1 hour after the burst would be expected to be 0.1 R/hr after 7 

hours and 0.01 R/hr after 49 hours. This rule seems to be valid for about 6 months following an explosion, 

after which the observed decay is somewhat faster than that predicted by this relationship. Activation 

products, in general, decay at a faster rate than the fission products. 

Fission products and activation products, along with un-fissioned uranium or plutonium from the device, 

constitute the radioactive material in the debris cloud, and this cloud and its fallout are the primary sources 

of the potential exposure to residual radiation. 

In a nuclear airburst in which the central core of intensely hot material, or fireball, does not touch the 

surface, the device residues (including the fission products, the activation products resulting from neutron 

interaction with device materials, and un-fissioned uranium and/or plutonium) are vaporized. These vapors 

condense as the fireball rises and cools, and the particles formed by the condensation are small and smokelike. They are carried up with the cloud to the altitude at which their rise stops, usually called the cloud 

stabilization altitude. The spread of this material then depends on the winds and weather. If the burst size is 

small, the cloud stabilization altitude will be in the lower atmosphere and the material will act like dust and 

return to the Earth's surface in a matter of weeks. Essentially all debris from bursts with yields equivalent to 

kilotons of TNT, will be down within 2 months. The areas in which this fallout material will be deposited 

will appear on maps as bands following the wind's direction. Larger bursts (yields equivalent to megatons of 

TNT) will have cloud stabilization altitudes in the stratosphere (above about 10 miles in the tropics); the 

radioactive material from such altitudes will not return to Earth for many months and its distribution will be 

much wider. Thus, airbursts contribute little potential for radiation exposure to personnel at the testing area, 

although there may be some residual and short-lived radiation coming from activated surface materials 

under the burst if the burst altitude is sufficiently low for neutrons to reach the surface. 

Surface and near-surface bursts pose larger potential radiation exposure problems. These bursts create more 

radioactive debris because more material is available for activation within range of the neutrons generated 

by the explosion. In such explosions the extreme heat vaporizes device materials and activated earth 

materials as well. These materials cool in the presence of additional material gouged out of the burst crater. 

This extra material causes the particles formed as the fireball cools to be larger in size, with radioactivity 

embedded in them or coating their surfaces. The rising cloud will lift these particles to altitudes that will 

depend on the particle size and shape and the power of the rising air currents in the cloud, which in turn 

depend on the energy of the burst. The largest particles will fall back into the crater or very near the burst 

area with the next largest falling nearby. It has been estimated that as much as 80 percent of the radioactive 

debris from a land-surface burst falls out within the first day following the burst. 

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Bursts on the surface of seawater generate particles consisting mainly of salt and water droplets that are 

smaller and lighter than the fallout particles from a land-surface burst. As a consequence, water-surface 

bursts produce less early fallout than similar devices detonated on land. The large-yield surface bursts in the 

PPG over relatively shallow lagoon waters or on the very little land surface probably formed a complex 

combination of land-surface and water-surface detonation particle-size characteristics. 

Detonations on towers may be considered as low airbursts or ground bursts, depending upon the relative 

height of the detonation and its yield. A larger burst will create more fallout than a smaller burst on an equal 

height tower, not only because of the additional fission products and weapon debris, but also because it will 

pull up more earth materials, or form a crater. In addition, the materials of the tower itself are a source of 

easily activated materials. The particles of the tower material may also act as centers for the debris vapors to 

condense on, to form the larger particles that lead to heavier early fallout. (DNA 6034F) 

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