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Mortality of Veteran Participants in the CROSSROADS Nuclear Test (1996)

Chapter:Appendix B: Particpant Description (DNA memorandum dated July 11, 1994)

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Suggested Citation:"Appendix B: Particpant Description (DNA memorandum dated July 11, 1994)." Institute of Medicine. 1996. Mortality of Veteran Participants in the CROSSROADS Nuclear Test. Washington, DC: The National Academies Press. doi: 10.17226/5428.
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B
Participant Description (DNA Memorandum dated July 11, 1994)

Suggested Citation:"Appendix B: Particpant Description (DNA memorandum dated July 11, 1994)." Institute of Medicine. 1996. Mortality of Veteran Participants in the CROSSROADS Nuclear Test. Washington, DC: The National Academies Press. doi: 10.17226/5428.
×

Explanatory Memorandum

Background

CROSSROADS was a two-shot atmospheric nuclear test series conducted at Bikini Atoll during July and August 1946. The first test (Shot ABLE) was a device dropped on 1 July 1946 from an aircraft and exploded at an altitude of 520 feet over an array of target ships. The second test (Shot BAKER) was detonated on 25 July 1946, 90 feet below the water's surface amongst an array of target ships.

Two hundred forty-two ships participated in Operation CROSSROADS. Over 39,300 U.S. Navy personnel have been identified as having participated in the operation. The ships that participated can be divided into three categories: support ships, remanned target ships and unremanned target ships. Support ships were present at the test site at some time during the operational period, but were not in the target area at the time of the shots. Remanned target ships were ships that were present in the target area at the time of the shots. The crews for these ships were evacuated to support ships at the time of the detonations. The damage and contamination of these ships was such that it was determined they could be remanned by their crews after the detonations. The third category of ships, unremanned target ships, were also present in the target area at the time of the detonations. However, their crews, which had been evacuated to support ships, could not permanently return to their home ships because the ships had either sunk or were too severely damaged or contaminated to be remanned. Most of the crews of the unremanned target ships were shipped as passengers back to Kwajalein, Pearl Harbor and California west coast ports. About 10% of the crews for the unremanned target ships were assigned as replacement crewmembers of support ships. The three categories of ships included many types such as battleships, cruisers, destroyers, oilers, troop transports, aircraft carriers, submarines, patrol, supply, salvage, yard and utility ships.

Operational Period and Operational Area

The Operational Area for this data collection effort is defined as Bikini Atoll. The Operational Period is defined as 1 July 1946 through 31 August 1946. All service members who were present in the Operational Area for any time during the Operational Period qualify for participation. Some personnel at Kwajalein and Enewetak also qualify as participants because they were at those locations to support the operation. The Post Operational Period for CROSSROADS extends from 1 September 1946 through 28 February 1947.

Suggested Citation:"Appendix B: Particpant Description (DNA memorandum dated July 11, 1994)." Institute of Medicine. 1996. Mortality of Veteran Participants in the CROSSROADS Nuclear Test. Washington, DC: The National Academies Press. doi: 10.17226/5428.
×

The activities of operational participants are documented throughout the Post Operational period to the extent possible.

Sources of Participant Information

The participants were identified from multiple sources such as service personnel records, unit diaries, ship deck logs, ship/unit muster rolls, ship/unit officer lists, unit histories, morning reports and operation participant listings. Great effort was expended to recover all relevant participation records. The quality, content and completeness of these records varies. The Army records are almost wholly insufficient to completely track participants. Most Army personnel arrived and departed by aircraft and there are no aviation records available to document arrival and departure dates. Army personnel also performed duties ashore at Bikini; however, available records do not document the specific activities of individuals ashore so these periods cannot be accounted for. Small segments of records have never been recovered and some units were so small that they never maintained individual records, e.g., small Navy vessels, such as ''yard'' craft with small crews, never maintained deck logs or crew lists.

Despite the great effort made to identify all CROSSROADS participants it is clear from the absence of complete records that not all participants have been found. "Staff Afloat" personnel aboard Navy ships were commonly not named and therefore not identifiable. This database is comprehensive in that every major participation element has been included but it has not been possible to identify all individual participants because of the inadequacies of the records.

Tracking of Participants

Units that entered the operational area prior to the first shot day generally have a participation start date of 1 July 1946. Units that entered the operational area after the first shot and during the operational period have a participation start date that corresponds to their actual date of arrival. During the operational period large-scale permanent and temporary transfers of personnel (mostly sailors) among the participating ships often occurred. The ships involved had differing levels of contamination which required that the sailors' service be tracked through all transfers among multiple ships. The periods of time spent aboard various ships are listed sequentially in the database. Where gaps in dates appear, they generally indicate a period of unknown location, either ashore or aboard an unidentified ship. Where possible, all sailors were tracked throughout their participation in the operational area at least to the point where they departed the ship that transported them from the operational area. Sailors who are not shown on available records to have departed their ship before its

Suggested Citation:"Appendix B: Particpant Description (DNA memorandum dated July 11, 1994)." Institute of Medicine. 1996. Mortality of Veteran Participants in the CROSSROADS Nuclear Test. Washington, DC: The National Academies Press. doi: 10.17226/5428.
×

radiological clearance are assumed to have remained aboard to that date (generally late fall or early 1947) at which time their participation terminated as well as their dose accrual.

Refinement of the Initial Data Base

In the initial data collection effort for this project over 2,500 sailors had incomplete names and were missing other essential data such as service numbers and rate/ratings. Through an extensive effort which involved ordering over 600 personnel records from the National Personnel Records Center in St. Louis, MO and multiple trips to the National Archives this number has been reduced to the absolute minimum.

Pseudo service numbers generated by a computer program have been assigned to participants for whom no service number could be found. These numbers can be identified by the prefix "DE" and/or the source code "23" The rate/rating is left blank for those participants for whom this information could not be found.

Participation Dates and Dose Reconstructing

The Start and stop participation dates and start and stop dose reconstruction dates will match for personnel who have been completely tracked. Some personnel have had "special" reconstructions computed as a result of VA claims or personal inquiries. These can generally be identified by the fact that they have reconstruction identification numbers in the database. Generic doses have been assigned to personnel of units that had special participation scenarios which made it impossible to document the activities of individual members of the unit. The participation and dose dates for personnel with generic doses commonly do not match. Personnel of the following units were assigned generic doses:

UNIT

MEAN DOSE

Det 1156 53rd Naval Const BN

1,140 mrem

Underwater Demolition Team 3

650 mrem

COMLCTGRU 21

1,350 mrem

COMLCTGRU 15

1,350 mrem

Suggested Citation:"Appendix B: Particpant Description (DNA memorandum dated July 11, 1994)." Institute of Medicine. 1996. Mortality of Veteran Participants in the CROSSROADS Nuclear Test. Washington, DC: The National Academies Press. doi: 10.17226/5428.
×

Doses were not computed for personnel whose participation status and activities could not be tracked/documented. These individuals often lack complete participation dates. The database may contain doses for these personnel but their source and accuracy have not been verified.

Dose Reconstruction

The doses were reconstructed based on the participation dates and ships to which the sailors were assigned and the sailor's rate/rating. In about 80% of the cases the participants have been assigned High, Mean, and Low doses. The remaining 20% only have a Mean dose assigned. Generic doses have been assigned to certain groups of individuals who had common participation scenarios but whose individual activities could not be specifically evaluated. In cases where individuals were assigned film badges their recorded doses are shown in addition to their reconstructed ones.

Engineer Ratings

Sailors who served below decks in engineering ratings (specialties) in close proximity to a ship's piping and evaporators had higher potential levels of radiation exposure, and thus received higher reconstructed doses than their nonengineering rated shipmates. Engineer rating are defined as: Carpenter Mates—CM, CM3, CM2, CM1, and CMC; Shipfitters—SF, SF3, SF2, SF1, and SFC; Water Tenders—WT, WT3, WT2, WT1, and WTC; Boilermakers—BT, BT3, BT2, BT1, and BTC; Fireman—F, FA, FN; and Machinist Mates—MM, MM3, MM2, MM1, and MMC. When engineers were in non-duty status i.e., sick, evacuation, transportation etc., their doses were computed at the nonengineering rate. The special provisions for engineers do not apply to submariners, seabees, and individuals with generic doses. The few sailors who started their participation as non-engineers and who were later promoted to an engineering rating during the participation period had their doses computed as non-engineers throughout their participation period.

Source Codes

Data elements within the database are linked to source codes to identify the source of the data. For example: if a piece of data was obtained from a deck log, the deck log source code (29) is linked to that data element. Attached is a list of source codes authorized for use in the NTPR database.

Suggested Citation:"Appendix B: Particpant Description (DNA memorandum dated July 11, 1994)." Institute of Medicine. 1996. Mortality of Veteran Participants in the CROSSROADS Nuclear Test. Washington, DC: The National Academies Press. doi: 10.17226/5428.
×

Participating Unit/Permanent Unit Data

The database contains Participating and Permanent Unit fields for each participant. The Participating Unit data reflects where the individual was during the relevant period. Doses were computed on the basis of the Participating Unit data. The Permanent Unit data is irrelevant to a participant's dose.

Commander Joint Task Force (CJTF-1) Medical Research Personnel, Boarding Team and RADSAFE Teams

Operation CROSSROADS was conducted under the command and control of CJTF-1. Approximately 1,100 personnel were assigned to CJTF-1. These personnel were assigned to conduct specialized functions such as instrumentation, oceanography, ordnance and electronic research. The nature of their duties required them to board target ships but dates and the ships boarded are not usually a matter of record. They have been tracked aboard their "home" and support ships and their doses have been computed on that basis. They can be identified in the database by the unit "CJTF 1" in the participating unit and/or permanent unit history data fields.

CJTF-1 personnel were also assigned as Boarding Teams and RADSAFE Team members. Their duties, to a far greater extent than other CJTF-1 personnel, required repeated and prolonged boarding of target ships. The doses for these individuals cannot be reliably reconstructed because of the absence of records documenting their presence aboard target ships. These individuals are identified as "Boarding Team" and "RADSAFE" in the participating unit field.

The duties of Medical Research personnel would have also required the boarding of target ships. However, their presence aboard the target ships is also not a matter of record. Their home ship was the USS BURLESON (APA 67). The reconstructed doses for these personnel are based on their time aboard BURLESON. These personnel are identified as "Medical Research" in the participating unit field.

Suggested Citation:"Appendix B: Particpant Description (DNA memorandum dated July 11, 1994)." Institute of Medicine. 1996. Mortality of Veteran Participants in the CROSSROADS Nuclear Test. Washington, DC: The National Academies Press. doi: 10.17226/5428.
×
Page99
Suggested Citation:"Appendix B: Particpant Description (DNA memorandum dated July 11, 1994)." Institute of Medicine. 1996. Mortality of Veteran Participants in the CROSSROADS Nuclear Test. Washington, DC: The National Academies Press. doi: 10.17226/5428.
×
Page100
Suggested Citation:"Appendix B: Particpant Description (DNA memorandum dated July 11, 1994)." Institute of Medicine. 1996. Mortality of Veteran Participants in the CROSSROADS Nuclear Test. Washington, DC: The National Academies Press. doi: 10.17226/5428.
×
Page101
Suggested Citation:"Appendix B: Particpant Description (DNA memorandum dated July 11, 1994)." Institute of Medicine. 1996. Mortality of Veteran Participants in the CROSSROADS Nuclear Test. Washington, DC: The National Academies Press. doi: 10.17226/5428.
×
Page102
Suggested Citation:"Appendix B: Particpant Description (DNA memorandum dated July 11, 1994)." Institute of Medicine. 1996. Mortality of Veteran Participants in the CROSSROADS Nuclear Test. Washington, DC: The National Academies Press. doi: 10.17226/5428.
×
Page103
Suggested Citation:"Appendix B: Particpant Description (DNA memorandum dated July 11, 1994)." Institute of Medicine. 1996. Mortality of Veteran Participants in the CROSSROADS Nuclear Test. Washington, DC: The National Academies Press. doi: 10.17226/5428.
×
Page104
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In 1946, approximately 40,000 U.S. military personnel participated in Operation CROSSROADS, an atmospheric nuclear test that took place at Bikini Atoll in the Marshall Islands. Congress passed a law directing the Veterans Administration to determine whether there were any long-term adverse health effects associated with exposure to ionizing radiation from the detonation of nuclear devices. This book contains the results of an extensive epidemiological study of the mortality of participants compared with a similar group of nonparticipants. Topics of discussion include a breakdown of the study rationale; an overview of other studies of veteran participants in nuclear tests; and descriptions of Operation CROSSROADS, data sources for the study, participant and comparison cohorts, exposure details, mortality ascertainment, and findings and conclusions.

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