SEC Petition Evaluation Report 

Petition SEC-00084 

Report Rev #: 1 Report Submittal Date: January 25, 2010

Petitioner Administrative Summary 

Petition Under Evaluation 

Petition # Petition 

Type 

Petition B 

Receipt Date DOE/AWE Facility Name 

SEC-00084 83.13 February 5, 2007 Nevada Test Site (NTS) 

Petitioner Class Definition 

All employees of the Department of Energy or any DOE contractor or subcontractor who worked in 

any areas of the Nevada Test Site from January 1, 1963 through September 30, 1992. 

Class Evaluated by NIOSH 

All employees of the Department of Energy or any Department of Energy contractor or subcontractor 

who worked in any areas of the Nevada Test Site from January 1, 1963 through December 31, 1992. 

NIOSH-Proposed Class(es) to be Added to the SEC 

All employees of the Department of Energy, its predecessor agencies, and its contractors and 

subcontractors who worked at the Nevada Test Site, from January 1, 1963 through December 31, 

1992, 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 established for one or more 

other classes of employees in the SEC. 

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 

SEC Petition Evaluation Report, SEC-00084, Rev. 0 Nevada Test Site (NTS) 

SEC Petition Evaluation Prepared By: [Signature on file] 1/25/10 

J. W. Neton Date 

SEC Evaluation Approved By: [Signature on file] 1/25/10 

Stuart L. Hinnefeld Date 
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Evaluation Report Summary: SEC-00084, Nevada Test Site (NTS) 

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

addresses a class of employees proposed for addition to the Special Exposure Cohort (SEC) per the 

Energy Employees Occupational Illness Compensation Program Act of 2000, as amended, 42 U.S.C. 

§ 7384 et seq. (EEOICPA) and 42 C.F.R. pt. 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. 

Petitioner-Requested Class Definition

Petition SEC-00084, qualified on April 4, 2007, requested that NIOSH consider the following class: 

All employees of the Department of Energy or any DOE contractor or subcontractor who worked in 

any areas of the Nevada Test Site from January 1, 1963 through September 30, 1992. 

Class Evaluated by NIOSH

Based on its preliminary research, NIOSH expanded the petitioner-requested class to the end of 1992 

to ensure that all testing activities that ended in 1992 were included in the evaluated class and possible 

proposed SEC class. This later end date also coincides with the implementation of the DOE 

Radiological Control Manual (DOE, 1992), which was implemented in 1993, and the implementation 

of the 1993 NTS internal technical basis document that demonstrates NTS compliance with 10 C.F.R. 

835 (NTS, 1993). Therefore, NIOSH defined the following class for further evaluation: All 

employees of the Department of Energy or any Department of Energy contractor or subcontractor who 

worked in any areas of the Nevada Test Site from January 1, 1963 through December 31, 1992. 

NIOSH-Proposed Class Definition

Based on its research of the class under evaluation, NIOSH has defined a single class of employees for 

which NIOSH cannot estimate radiation doses received from internal exposure with sufficient 

accuracy. The NIOSH-proposed class includes all employees of the Department of Energy, its 

predecessor agencies, and its contractors and subcontractors who worked at the Nevada Test Site, 

from January 1, 1963 through December 31, 1992, 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 established for one or more other classes of employees in the SEC. The class has been 

proposed for addition to the SEC because the feasibility of reconstructing doses associated with 

potential internal exposures may be directly impacted by data gaps for certain radionuclides over the 

span of operations, and the actual exposure risk associated with various exposure scenarios (see 

Section 3.0). 

 

Feasibility of Dose Reconstruction

Per EEOICPA and 42 C.F.R. § 83.13(c)(1), NIOSH has established that it does not have access to 

sufficient information to: (1) estimate the maximum radiation dose, for every type of cancer for which 

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

member of the class; or (2) estimate radiation doses of members of the class more precisely than an 

estimate of maximum dose. Information available from the site profile and additional resources is not 
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sufficient to document or estimate the maximum internal and external potential exposure to members 

of the proposed class under plausible circumstances during the specified period from January 1, 1963 

through December 31, 1992. 

The feasibility findings from this Evaluation Report Revision are as follows: 

 NIOSH lacks sufficient information, which includes biological monitoring data, sufficient air 

monitoring information, or sufficient process and radiological source information, to allow it to 

estimate with sufficient accuracy the potential internal exposures to various radionuclides to which 

the proposed class may have been subjected during the period from January 1, 1963 through 

December 31, 1992. 

 Although NIOSH found that it is not possible to completely reconstruct internal radiation doses 

for the proposed class, NIOSH intends to use any internal and external monitoring data that may 

become available for an individual claim (and that can be interpreted using existing NIOSH dose 

reconstruction processes or procedures). Therefore, dose reconstructions for individuals employed 

at the Nevada Test Site during the period from January 1, 1963 through December 31, 1992, but 

who do not qualify for inclusion in the SEC, may be performed using these data as appropriate. 

Per EEOICPA and 42 C.F.R. § 83.13(c)(1), NIOSH has established that it has access to sufficient 

information to: (1) estimate the maximum radiation dose incurred by any member of the class; or (2) 

estimate radiation doses more precisely than a maximum dose estimate for the period from January 1, 

1993 forward. Information available from the Site Profile and additional resources is sufficient to 

document or estimate the maximum internal and external potential exposure to members of the 

proposed class under plausible circumstances during this period. 

Health Endangerment Determination

Per EEOICPA and 42 C.F.R. § 83.13(c)(3), a health endangerment determination is required for the 

period from January 1, 1963 through December 31, 1992 because NIOSH has determined that it does 

not have sufficient information to estimate dose for the members of the proposed class. 

NIOSH did not identify any evidence supplied by the petitioners or from other resources that would 

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

involved exceptionally high-level exposures. Consequently, NIOSH has determined that health was 

endangered for those workers covered by this evaluation who were employed for at least 250 

aggregated work days either solely under their employment or in combination with work days within 

the parameters established for other SEC classes (excluding aggregate work day requirements). 

 

Per EEOICPA and 42 C.F.R. § 83.13(c)(3), a health endangerment determination is not required for 

the period from January 1, 1993 forward because NIOSH has determined that it has sufficient 

information to estimate dose for the members of the proposed class. 
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Table of Contents 

Evaluation Report Summary: SEC-00084, Nevada Test Site (NTS) ...................................................... 3

1.0 Purpose and Scope.......................................................................................................................... 9

2.0 Introduction .................................................................................................................................... 9

3.0 SEC-00084 Nevada Test Site Class Definitions .......................................................................... 10

3.1 Petitioner-Requested Class Definition and Basis................................................................ 10

3.2 Class Evaluated by NIOSH ................................................................................................. 12

3.3 NIOSH-Proposed Class(es) to be Added to the SEC .......................................................... 12

4.0 Data Sources Reviewed by NIOSH.............................................................................................. 13

4.1 Site Profile and Technical Basis Documents (TBDs) ......................................................... 13

4.2 ORAU Technical Information Bulletins (OTIBs) and Procedures ..................................... 14

4.3 Facility Employees, Survivors, and Experts........................................................................ 15

4.4 Previous Dose Reconstructions ........................................................................................... 16

4.5 NIOSH Site Research Database .......................................................................................... 17

4.6 Documentation and/or Affidavits Provided by Petitioners ................................................. 17

4.7 Other Technical Sources...................................................................................................... 19

5.0 Radiological Operations Relevant to the Proposed Class ............................................................ 19

5.1 NTS Plant and Process Descriptions ................................................................................... 19

5.2 NTS Functions..................................................................................................................... 21

5.2.1 Atmospheric Weapons Testing................................................................................ 22

5.2.2 Safety Testing.......................................................................................................... 22

5.2.3 Big Explosive Experiments ..................................................................................... 22

5.2.4 Underground Testing............................................................................................... 23

5.2.4.1 Tests in Vertical Drill Holes..................................................................... 23

5.2.4.2 Tests in Mined Tunnels ............................................................................ 23

5.2.4.3 Routine Tunnel Operations....................................................................... 24

5.2.5 Nuclear Reactor Development Testing ................................................................... 26

5.2.6 Shallow Borehole Testing ....................................................................................... 26

5.2.7 Waste Disposal ........................................................................................................ 26

5.2.7.1 Crater Disposal – Area 3 Radioactive Waste Management Site .............. 26

5.2.7.2 Shallow-Land Burial – Area 5 Low-Level Radioactive Waste 

Management Site...................................................................................... 27

5.2.7.3 Greater Confinement Disposal – Area 5 Radioactive Waste Management 

Site............................................................................................................ 27

5.2.8 U1a Underground Complex .................................................................................... 27

5.2.9 Analytical Laboratory, Research, and Support Operations ..................................... 28

5.2.10 Summary of Key NTS Facilities ............................................................................. 29

5.3 Radiological Exposure Sources from NTS Operations....................................................... 30

5.3.1 Alpha Particle Emissions......................................................................................... 31

5.3.2 Beta Radiation Fields .............................................................................................. 31

5.3.3 Neutron Exposures .................................................................................................. 33
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5.3.4 Photon Exposures .................................................................................................... 34

6.0 Summary of Available Monitoring Data for the Proposed Class................................................. 34

6.1 NTS Internal Monitoring Data ............................................................................................ 35

6.2 NTS External Monitoring Data ........................................................................................... 37

6.3 NTS Air Sampling Data ...................................................................................................... 37

7.0 Feasibility of Dose Reconstruction for the Proposed Class ......................................................... 39

7.1 Pedigree of NTS Data.......................................................................................................... 39

7.1.1 Internal Data Review............................................................................................... 39

7.1.2 External Data Review.............................................................................................. 47

7.2 Internal Radiation Doses at NTS......................................................................................... 48

7.2.1 Bioassay Protocols Performed at NTS .................................................................... 55

7.2.1.1 Discussion of In Vitro Bioassay and Radionuclides................................. 55

7.2.1.2 Discussion of In Vivo Bioassay and Radionuclides ................................. 58

7.2.1.3 Air Monitoring Data and Documentation................................................. 60

7.2.1.4 Radon........................................................................................................ 60

7.2.2 Ambient Environmental Internal Radiation Doses at NTS ..................................... 62

7.2.2.1 Ambient Environmental Radiation—Air Sampling ................................. 63

7.2.2.2 Ambient Environmental Radiation—Soil Sampling................................ 63

7.2.2.3 Statistical Modeling of Environmental Data for Dose Reconstruction.... 65

7.2.3 Internal Dose Reconstruction Considerations ......................................................... 66

7.2.4 Internal Dose Reconstruction Feasibility Conclusion ............................................. 68

7.3 External Radiation Doses at NTS........................................................................................ 68

7.3.1 Process-Related External Radiation Doses at NTS ................................................. 68

7.3.1.1 Radiation Exposure Environment............................................................. 68

7.3.1.2 History of Whole-Body External Monitoring .......................................... 70

7.3.1.3 History of Extremity Monitoring.............................................................. 70

7.3.1.4 Dosimetry Records ................................................................................... 71

7.3.1.5 Application of Co-Worker Data for External Dose Reconstruction ........ 71

7.3.2 Ambient Environmental External Radiation Doses at NTS .................................... 71

7.3.3 NTS Occupational X-Ray Examinations................................................................. 72

7.3.4 External Dose Reconstruction ................................................................................. 73

7.3.4.1 Photon Dose.............................................................................................. 74

7.3.4.2 Electron Dose ........................................................................................... 74

7.3.4.3 Neutron Dose............................................................................................ 75

7.3.4.4 Medical X-ray........................................................................................... 75

7.3.5 External Dose Reconstruction Feasibility Conclusion............................................ 75

7.4 Evaluation of Petition Basis for SEC-00084 ....................................................................... 76

7.4.1 Evaluation of Major Topics Detailed in Petition SEC-00084 ................................. 77

7.4.1.1 Hot Particle Dose...................................................................................... 77

7.4.1.2 Defeating the Universal Badging Policy .................................................. 77

7.4.1.3 Resuspension ............................................................................................ 79

7.4.1.4 Record Verification and Validation.......................................................... 79
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7.4.2 Evaluation of Specific Petitioner Statements in SEC-00084 .................................. 80

7.4.2.1 Specific Affidavit Statement 1 ................................................................. 80

7.4.2.2 Specific Affidavit Statement 2 ................................................................. 80

7.4.2.3 Specific Affidavit Statement 3 ................................................................. 81

7.4.2.4 Specific Affidavit Statement 4 ................................................................. 81

7.4.2.5 Specific Affidavit Statement 5 ................................................................. 81

7.4.2.6 Specific Affidavit Statement 6 ................................................................. 82

7.4.2.7 Specific Affidavit Statement 7 ................................................................. 82

7.4.2.8 Specific Affidavit Statement 8 ................................................................. 82

7.4.2.9 Specific Affidavit Statement 9 ................................................................. 83

7.4.2.10 Specific Affidavit Statement 10 ............................................................... 83

7.4.2.11 Specific Affidavit Statement 11 ............................................................... 83

7.4.2.12 Specific Affidavit Statement 12 ............................................................... 84

7.4.2.13 Specific Affidavit Statement 13 ............................................................... 84

7.4.2.14 Specific Affidavit Statement 14 ............................................................... 84

7.4.2.15 Specific Affidavit Statement 15 ............................................................... 85

7.4.2.16 Specific Affidavit Statement 16 ............................................................... 85

7.5 Other Issues Relevant to the Petition Identified During the Evaluation ............................. 85

7.6 Summary of Feasibility Findings for Petition SEC-00084.................................................. 87

8.0 Evaluation of Health Endangerment for Petition SEC-00084...................................................... 87

9.0 NIOSH-Proposed Class for Petition SEC-00084 ......................................................................... 88

10.0 References .................................................................................................................................... 89
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Figure 

6-1: NTS Urine Bioassay Samples, 1970-1994..................................................................................... 36

Tables 

4-1: No. of NTS Claims Submitted Under the Dose Reconstruction Rule ........................................... 16

5-1: NTS Development/Activities......................................................................................................... 21

5-2: Key NTS Areas, Operations, and Dates of Operation ................................................................... 29

5-3: NTS Alpha-Emitting Radionuclides .............................................................................................. 31

5-4: NTS Beta-Emitting Radionuclides................................................................................................. 32

5-5: NTS Areas and Activities with Potential Neutron Exposure......................................................... 33

7-1: Summary of Recorded External and Internal Dose Based on Employment .................................. 40

7-2: Drillback Re-suspension, Reentry/Mineback Re-suspension, Radionuclides of Concern for 

 Dose V. Time After Test ................................................................................................................ 50

7-3: Radionuclides of Concern in Atmospheric Weapons Test Areas .................................................. 52

7-4: Radionuclides of Concern in Crater Disposal-Area 3 RWMS ...................................................... 53

7-5: Radionuclides of Concern in Shallow Land Burial-Area 5 ........................................................... 53

7-6: Radionuclides of Concern in Radiation Instrument Calibration Facilities .................................... 54

7-7: Radionuclides of Concern in Radiochemistry and Counting Laboratories.................................... 54

7-8: Respiratory Protection Action Levels ............................................................................................ 55

7-9: Number of Workers1 Receiving In Vivo Monitoring Before 1967 ................................................ 59

7-10: Radon/Thoron Daughter Concentrations for N-Tunnel in 1991 and 1992 .................................. 61

7-11: Radon/Thoron Daughter Concentrations for P-Tunnel in 1991 and 1992................................... 62

7-12: Inventory of Contaminated Soil, Curies ...................................................................................... 64

7-13: Radionuclide Area Soil Deposition (Bq/m2)................................................................................ 64

7-14: Frequency of PA and LAT Chest X-rays at NTS ........................................................................ 73

7-15: Results of Interviews regarding Defeat of the Universal Badging Policy ................................... 78

7-16: Summary of Feasibility Findings for SEC-00084........................................................................ 87
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SEC Petition Evaluation Report for SEC-00084

1.0 Purpose and Scope 

This report evaluates the feasibility of reconstructing doses for all employees of the Department of 

Energy (DOE) or any DOE contractor or subcontractor who worked in any areas of the Nevada Test 

Site from January 1, 1963 through December 31, 1992. It provides information and analyses germane 

to considering a petition for adding a class of employees to the congressionally-created SEC. 

This report does not make any determinations concerning the feasibility of dose reconstruction that 

necessarily apply to any individual energy employee who might require a dose reconstruction from 

NIOSH. This report also does not contain the final determination as to whether the proposed class 

will be added to the SEC (see Section 2.0). 

This evaluation was conducted in accordance with the requirements of EEOICPA, 42 C.F.R. pt. 83, 

and the guidance contained in the Office of Compensation Analysis and Support’s (OCAS) Internal 

Procedures for the Evaluation of Special Exposure Cohort Petitions, OCAS-PR-004. 

2.0 Introduction 

Both EEOICPA and 42 C.F.R. pt. 83 require NIOSH to evaluate qualified petitions requesting that the 

Department of Health and Human Services (HHS) add a class of employees to the SEC. The 

evaluation is intended to provide a fair, science-based determination of whether it is feasible to 

estimate with sufficient accuracy the radiation doses of the class of employees through NIOSH dose 

reconstructions.1 

42 C.F.R. § 83.13(c)(1) states: Radiation doses can be estimated with sufficient accuracy if NIOSH 

has established that it has access to sufficient information to estimate the maximum radiation dose, 

for every type of cancer for which radiation doses are reconstructed, that could have been incurred in 

plausible circumstances by any member of the class, or if NIOSH has established that it has access to 

sufficient information to estimate the radiation doses of members of the class more precisely than an 

estimate of the maximum radiation dose.

 

Under 42 C.F.R. § 83.13(c)(3), if it is not feasible to estimate with sufficient accuracy radiation doses 

for members of the class, then NIOSH must determine that 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 at least 250 aggregated work days within the parameters established for the 

1

 NIOSH dose reconstructions under EEOICPA are performed using the methods promulgated under 42 C.F.R. pt. 82 and 

the detailed implementation guidelines available at http://www.cdc.gov/niosh/ocas. 
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class or in combination with work days within the parameters established for other SEC classes 

(excluding aggregate work day requirements). 

NIOSH is required to document its evaluation in a report, and to do so, relies upon both its own dose 

reconstruction expertise as well as technical support from its contractor, Oak Ridge Associated 

Universities (ORAU). Once completed, NIOSH provides the report to both the petitioner(s) and to the 

Advisory Board on Radiation and Worker Health (Board). The Board will consider the NIOSH 

evaluation report, together with the petition, petitioner(s) comments, and other information the Board 

considers appropriate, in order 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 a decision on behalf of HHS. The Secretary 

of HHS will make the final decision, taking into account the NIOSH evaluation, the advice of the 

Board, and the proposed decision issued by NIOSH. As part of this decision process, petitioners may 

seek a review of certain types of final decisions issued by the Secretary of HHS.2

 

3.0 SEC-00084 Nevada Test Site Class Definitions 

The following subsections address the evolution of the class definition for SEC-00084, Nevada Test 

Site. When a petition is submitted, the requested class definition is reviewed as submitted. Based on 

its review of the available site information and data, NIOSH will make a determination whether to 

qualify for full evaluation all, some, or no part of the petitioner-requested class. If some portion of the 

petitioner-requested class is qualified, NIOSH will specify that class along with a justification for any 

modification of petitioner’s class. After a full evaluation of the qualified class, NIOSH will determine 

whether to propose a class for addition to the SEC and will specify that proposed class definition. 

3.1 Petitioner-Requested Class Definition and Basis 

Petition SEC-00084, qualified on April 4, 2007, requested that NIOSH consider the following class 

for addition to the SEC:

A Class member is any employee of the Department of Energy (DOE) or any DOE contractor or 

subcontractor during the period from January 1, 1963 through September 30, 1992, who was: 

(1) present during an underground nuclear test and/or performed a drillback, tunnel reentry, or 

cleanup work following such test at the Nevada Test Site (NTS)(without regard to the duration of 

employment); 

(2) present at an event involving the venting of an underground test or during a planned or 

unplanned radiation release at NTS; 

(3) present for tests or post-test activities related to the Nuclear Rocket Testing Program; 

(4) assigned to work at Area 51 (or other classified program areas); 

2

 See 42 C.F.R. pt. 83 for a full description of the procedures summarized here. Additional internal procedures are 

available at http://www.cdc.gov/niosh/ocas. 
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(5) employed at NTS in a job activity that was monitored for exposure to ionizing radiation or 

worked in a job activity that is or was comparable to a job that is, was, or should have been 

monitored for exposure to ionizing radiation at NTS, or in combination with work days with the 

parameters established for one or more other classes of employees in the Special Exposure 

Cohort (SEC).

Based on NIOSH’s consultation call with one petitioner, the petitioners revised the original class 

definition to include: All employees of the Department of Energy or any DOE contractor or 

subcontractor who worked in any areas of the Nevada Test Site from January 1, 1963 through 

September 30, 1992. 

The petitioners provided information and affidavit statements in support of their belief that accurate 

dose reconstruction is impossible for the Nevada Test Site (NTS) workers in question. NIOSH 

deemed the following information and affidavit statements sufficient to qualify SEC-00084 for 

evaluation: 

The petition, submitted by two former workers and one survivor, proposes that it is 

impossible to adequately reconstruct the dose for members of the proposed class because 

exposures were unmonitored, unrecorded, or inadequately monitored (involving both 

incidents and routine practices). The petition contends that information necessary for 

adequate dose reconstruction is unavailable for the following reasons: 1) the strict 

confidentiality in which that information was held by the workers, 2) inadequate 

monitoring, 3) NIOSH lacks a method to estimate internal dose through 1967, 4) NIOSH 

does not account for hot particle doses, 5) exposure to radon is improperly estimated, 6) the 

presence of high-fired oxides resulting from atmospheric weapons testing has not been 

investigated, 7) DOE records used by NIOSH have not been subject to verification and 

validation, 8) possible lost or destroyed NTS monitoring records, and 9) workers often (for 

various reasons) did not wear dosimetry badges. 

The petition included several affidavits asserting that the external monitoring program was 

circumvented by personnel deliberately removing their badges in radiological control areas in 

efforts to comply with supervisory instructions. Additionally, affidavits were provided stating that 

monitoring records that should exist, do not exist. 

The petitioners also indicated the petition was based on unmonitored, unrecorded, or inadequately 

monitored and recorded exposure incidents. The petition identifies eight of the ten “unexpected 

releases of radioactivity” as listed in the NTS Site Profile document as incidents. These eight 

incidents were specifically identified as having occurred during the period addressed by this 

petition. While these events have been studied historically and are well-documented sources of 

exposure, they are specifically excluded from the scope of the NTS Site Profile (ORAUT-TKBS0008-6). While these events do not clearly qualify as incidents as defined by the program, the 

issue was deemed worthy of further examination during the evaluation of this petition. 

The information and statements provided by the petitioner qualified the petition for further 

consideration by NIOSH, the Board, and HHS. The details of the petition basis are addressed in 

Section 7.4. 
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3.2 Class Evaluated by NIOSH 

Based on its preliminary research, NIOSH expanded the petitioner-requested class to the end of 1992 

to ensure that all testing activities that ended in 1992 were included in the evaluated class and possible 

proposed SEC class. This later end date also coincides with the implementation of the DOE 

Radiological Control Manual (DOE, 1992), which was implemented in 1993, and the implementation 

of the 1993 NTS internal technical basis document that demonstrates NTS compliance with 10 C.F.R. 

835 (NTS, 1993). Therefore, NIOSH defined the following class for further evaluation: All 

employees of the Department of Energy or any Department of Energy contractor or subcontractor who 

worked in any areas of the Nevada Test Site from January 1, 1963 through December 31, 1992. 

3.3 NIOSH-Proposed Class(es) to be Added to the SEC 

NIOSH presented an SEC Petition Evaluation Report for Petition SEC-00084, Nevada Test Site to the 

Presidential Advisory Board on Radiation and Worker Health during the Advisory Board’s regular 

meeting on January 9, 2008 (NIOSH, 2007). The report (Rev. 0 of this document) evaluated the 

feasibility of reconstructing radiation doses of workers who worked in any area at the Nevada Test 

Site during the period January 1, 1963 through September 30, 1992. After presentation of the report 

to the Advisory Board, the Board convened a working group to evaluate the adequacy of NIOSH’s 

evaluation. A detailed review of the evaluation report resulted in a number of concerns that the Board 

working group identified for further investigation. In response to these findings, additional research 

conducted by NIOSH and the Board’s support contractor, Sanford Cohen & Associates (SC&A), has 

(with one exception) resulted in the resolution of the technical issues between SC&A and NIOSH. 

The remaining issue of concern between SC&A and NIOSH is the ability of NIOSH to bound internal 

exposures for unmonitored workers who had the potential for inhalation and/or ingestion of 

radioactive material. This document (Rev. 1) summarizes NIOSH’s analysis of the adequacy of 

bioassay data during post-1963 operations at the Nevada Test Site (NTS) and presents its analytical 

conclusions. 

Based on its research, NIOSH has obtained external monitoring data, source term information, and 

process information that allow dose reconstruction of external exposure to be performed with 

sufficient accuracy for all monitored workers at NTS. 

NIOSH has identified data gaps that exist in the electronically-available bioassay data for certain 

radionuclides and time periods. The reconstruction of internal doses at NTS is also complicated by 

the variety of the radionuclides to which workers may have been exposed. Based on its analysis of the 

available resources, NIOSH recommends that the following class be included in the SEC: All 

employees of the Department of Energy, its predecessor agencies, and its contractors and 

subcontractors who worked at the Nevada Test Site, from January 1, 1963 through December 31, 

1992, 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 established for one or more 

other classes of employees in the SEC. 
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4.0 Data Sources Reviewed by NIOSH 

As a standard practice, NIOSH completed an extensive database and Internet search for information 

regarding the Nevada Test Site. The database search included the DOE Legacy Management 

Considered Sites database, the DOE Office of Scientific and Technical Information (OSTI) database, 

the Energy Citations database, the Atomic Energy Technical Report database, and the Hanford 

Declassified Document Retrieval System. In addition to general Internet searches, the NIOSH 

Internet search included OSTI OpenNet Advanced searches, OSTI Information Bridge Fielded 

searches, Nuclear Regulatory Commission (NRC) Agency-wide Documents Access and Management 

(ADAMS) web searches, the DOE Office of Human Radiation Experiments website, and the DOENational Nuclear Security Administration-Nevada Site Office-search. 

In addition to the database and Internet searches listed above, NIOSH identified and reviewed 

numerous data sources to determine information relevant to determining the feasibility of dose 

reconstruction for the class of employees under evaluation. This included determining the availability 

of information on personal monitoring, area monitoring, industrial processes, and radiation source 

materials. The following subsections summarize the data sources identified and reviewed by NIOSH. 

Since Rev. 0 of this Evaluation Report was published in September 2007 (NIOSH, 2007), NIOSH has 

obtained the complete set of electronic bioassay records from NTS (NTS Bioassay Data, 2009). The 

following subsections summarize the data sources identified and reviewed by NIOSH. 

4.1 Site Profile and Technical Basis Documents (TBDs) 

A Site Profile provides specific information concerning the documentation of historical practices at 

the specified site. Dose reconstructors can use the Site Profile to evaluate internal and external 

dosimetry data for monitored and unmonitored workers, and to supplement, or substitute for, 

individual monitoring data. A Site Profile consists of an Introduction and five Technical Basis 

Documents (TBDs) that provide process history information, information on personal and area 

monitoring, radiation source descriptions, and references to primary documents relevant to the 

radiological operations at the site. The Site Profile for a small site may consist of a single document. 

As part of NIOSH’s evaluation detailed herein, it examined the following TBDs for insights into NTS 

operations or related topics/operations at other sites: 

 Technical Basis Document for the Nevada Test Site – Introduction, ORAUT-TKBS-0008-1; Rev. 

00 PC-1; July 20, 2006; SRDB Ref ID: 29994 

 Technical Basis Document for the Nevada Test Site – Site Description, ORAUT-TKBS-0008-2; 

Rev. 00; February 02, 2004; SRDB Ref ID: 19793

 Technical Basis Document for the Nevada Test Site – Occupational Medical Dose, ORAUTTKBS-0008-3; Rev. 01; June 22, 2007; SRDB Ref ID: 19794 

 Technical Basis Document for the Nevada Test Site – Occupational Environmental Dose, 

ORAUT-TKBS-0008-4; Rev. 00 PC-1; December 08, 2006; SRDB Ref ID: 29995 
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 Technical Basis Document for the Nevada Test Site – Occupational Internal Dose, ORAUTTKBS-0008-5; Rev. 00 PC-1; July 20, 2006; SRDB Ref ID: 29996 

 Technical Basis Document for the Nevada Test Site – Occupational External Dose, ORAUTTKBS-0008-6; Rev. 01; July 30, 2007; SRDB Ref ID: 34013 

 Lawrence Livermore National Laboratory – Occupational Internal Dose, ORAUT-TKBS-0035-5; 

Rev. 01 C; July 09, 2007; SRDB Ref ID: 19558

4.2 ORAU Technical Information Bulletins (OTIBs) and Procedures 

An ORAU Technical Information Bulletin (OTIB) is a general working document that provides 

guidance for preparing dose reconstructions at particular sites or categories of sites. An ORAU 

Procedure provides specific requirements and guidance regarding EEOICPA project-level activities, 

including preparation of dose reconstructions at particular sites or categories of sites. NIOSH 

reviewed the following OTIBs and procedures as part of its evaluation: 

 OTIB: Maximum Internal Dose Estimates for Certain DOE Complex Claims, ORAUT-OTIB0002, Rev. 02; February 7, 2007; SRDB Ref ID: 29947 

 OTIB: Dose Reconstruction from Occupationally Related Diagnostic X-Ray Procedures, 

ORAUT-OTIB-0006, Rev. 03 PC-1; December 21, 2005; SRDB Ref ID: 20220 

 OTIB: Assignment of Environmental Internal Doses for Employees Not Exposed to Airborne 

Radionuclides in the Workplace, ORAUT-OTIB-0014, Rev. 00; June 22, 2004; SRDB Ref ID: 

19432 

 OTIB: Interpretation of Dosimetry Data for Assignment of Shallow Dose, ORAUT-OTIB-0017, 

Rev. 01; October 11, 2005; SRDB Ref ID: 19434 

 OTIB: Internal Dose Overestimates for Facilities with Air Sampling Programs, ORAUT-OTIB0018, Rev. 01; August 09, 2005; SRDB Ref ID: 19436 

 OTIB: Estimating Doses for Plutonium Strongly Retained in the Lung, ORAUT-OTIB-0049, Rev. 

00; February 6, 2007; SRDB Ref ID: 29975 

 PROC: Occupational Onsite Ambient Dose Reconstruction for DOE Sites, ORAUT-PROC-0060, 

Rev. 01; June 28, 2006; SRDB Ref ID: 29986

 PROC: Occupational X-Ray Dose Reconstruction for DOE Sites, ORAUT-PROC-0061, Rev. 01; 

July 21, 2006; SRDB Ref ID: 29987
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4.3 Facility Employees, Survivors, and Experts 

To obtain additional information, NIOSH interviewed former NTS employees and survivors of former 

employees. Interviewee selection was based on the availability to be interviewed, as well as 

information regarding job description and potential knowledge of hazard conditions at NTS. Whereas 

considerable information regarding the radiation protection program has previously been collected 

from Radiation Protection and Safety personnel, the emphasis on selection of interviewees was on 

trades personnel, security staff, and administrative personnel. The interviews ultimately included 

employees and survivors representing a wide range of NTS experiences. Information obtained during 

the interviews contributed to the general knowledge of NTS conditions and monitoring practices and 

included information regarding records from Area 12 for the period 1970-1995 that were collected and 

buried in a site landfill. These records included: time records, mine rescue records, sign in/sign out 

records, logbooks, incident/accident reports – Form 1250, injury reports, personnel rosters, and safety 

meeting records. 

 Personal Communication, 2005, Personal Communication with [Names Redacted]; July 22, 2005; 

SRDB Ref ID: Not currently assigned 

 Personal Communication, 2007a, Personal Communication with a Security Officer; Telephone 

Interview by B. Murray and C. Miles; 1100 EDT July 16, 2007; SRDB Ref ID: 34046 

 Personal Communication, 2007b, Personal Communication with a Tunnel Miner/Core Driller; 

Telephone Interview by B. Murray and C. Miles; 1430 EDT July 16, 2007; SRDB Ref ID: 34051

 Personal Communication, 2007c, Personal Communication with a former records 

manager/administrative/clerical supervisor for underground tests; Telephone Interview by B. 

Murray and C. Miles; 1300 EDT July 18, 2007; SRDB Ref ID: 34049

 Personal Communication, 2007d, Personal Communication with the survivor of a Nuclear Rocket 

Development Station employee; Telephone Interview by B. Murray and C. Miles; 1200 EDT July 

18, 2007; SRDB Ref ID: 34052 

 Personal Communication, 2007e, Personal Communication with a construction support employee; 

Telephone Interview by B. Murray and C. Miles; 1400 EDT July 18, 2007; SRDB Ref ID: 34074

 Personal Communication, 2007f, Personal Communication with two survivors of a test engineer; 

Telephone Interview by B. Murray and C. Miles; 1600 EDT July 18, 2007; SRDB Ref ID: 34035 

 Personal Communication, 2007g, Personal Communication with a custodial employee/shaft 

miner; Telephone Interview by B. Murray and C. Miles; 1130 EDT July 19, 2007; SRDB Ref ID: 

34038 

 Personal Communication, 2007h, Personal Communication with a plumber/pipefitter; Telephone 

Interview by B. Murray and C. Miles; 1200 EDT July 23, 2007; SRDB Ref ID: 34034
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 Personal Communication, 2007i, Personal Communication with a Security Officer; Telephone 

Interview by B. Murray and C. Miles; 1330 EDT July 23, 2007; SRDB Ref ID: 34037

 Personal Communication, 2007j, Personal Communication with an AEC Health Physicist; email 

correspondence to B. Murray and C. Miles; July 25, 2007; SRDB Ref ID: 34036 

 Personal Communication, 2007k, Personal Communication with a Health Physicist; Telephone 

Interview by B. Murray and C. Miles; 1100 EDT July 25, 2007; SRDB Ref ID: 34039

 Personal Communication, 2007l, Personal Communication with a Health Physicist; Telephone 

Interview by B. Murray and C. Miles; 1230 EDT July 25, 2007; SRDB Ref ID: 34044 

 Personal Communication, 2007m, Personal Communication with a Radiological Control 

Technician; Telephone Interview by B. Murray and C. Miles; 1400 EDT August 06, 2007; SRDB 

Ref ID: 34064 

 Personal Communication, 2007n, Personal Communication with an Operating Engineer; 

Telephone Interview by B. Murray and C. Miles; 0900 EDT August 10, 2007; SRDB Ref ID: 

34065 

4.4 Previous Dose Reconstructions 

NIOSH reviewed its NIOSH OCAS Claims Tracking System (NOCTS) to locate EEOICPA-related 

dose reconstructions that might provide information relevant to the petition evaluation. Table 4-1 

summarizes the results of this review for the period of January 1, 1963 through December 31, 1992. 

(NOCTS data available as of January 22, 2010) 

Table 4-1: No. of NTS Claims Submitted Under the Dose Reconstruction Rule 

Description Totals 

Total number of claims submitted for dose reconstruction 1858 

Total number of claims submitted for energy employees who meet the definition criteria for the class 

under evaluation (January 1, 1963 through December 31, 1992). 1704 

Number of dose reconstructions completed for energy employees who meet the definition criteria for 

the class under evaluation (i.e., the number of such claims completed by NIOSH and submitted to the 

Department of Labor for final approval). 1165 

Number of claims for which internal dosimetry records were obtained for the identified years in the 

evaluated class definition 555 

Number of claims for which external dosimetry records were obtained for the identified years in the 

evaluated class definition 1679 
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NIOSH reviewed each claim to determine whether internal and/or external personal monitoring 

records could be obtained for the employee. Of the total number of claims submitted for energy 

employees who were employed during the years identified in the proposed class definition (1704), 

approximately one third have internal monitoring data available and nearly all have external 

monitoring data available. As of January 22, 2010, nine (9) claims had not received a response from 

DOE for exposure records. 

4.5 NIOSH Site Research Database 

NIOSH also examined its Site Research Database (SRDB) to locate documents supporting the 

assessment of the evaluated class. These documents were evaluated for their relevance to this 

petition. The documents include historical background on dosimetry monitoring and procedures, air 

sampling, soil sampling, the radiation safety program, radiation studies, access control/re-entry 

requirements, and operational requirements for various areas/operations. Also included are logs, 

radiation safety reports, general safety reports, environmental reports and studies, operations manuals, 

and survey documentation. 

During the initial evaluation of the class, 850 documents in this database were identified as pertaining 

to NTS. NIOSH has performed additional data captures at NTS since the evaluation report for the site 

was published in September 2007. As of January 2010, there were 1,314 documents in the Site 

Research Database (SRDB) pertaining to NTS; thus, 464 additional documents have been captured, 

reviewed, and uploaded into the SRDB since the initial evaluation report. 

4.6 Documentation and/or Affidavits Provided by Petitioners 

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

petitioners: 

Ten affidavits, seven from workers and three from survivors: 

 Affidavit from Former Laborer/Labor Foreman, Attachment 4; January 10, 2007; OSA Ref ID: 

102555 

 Affidavit from Former Driller/Drill Supervisor/Project Manager of Drilling, Attachment 5; 

January 17, 2007; OSA Ref ID: 102556 

 Affidavit from Former Foreman/Pipe-fitter/Welder, Attachment 6; January 10, 2006; OSA Ref ID: 

102557 

 Affidavit from Former Union President, Attachment 7; January 29, 2007; OSA Ref ID: 102558 

 Affidavit from Survivor, Attachment 10; January 18, 2007; OSA Ref ID: 102541 

 Affidavit from Former Carpenter’s Apprentice/Carpenter/Welder, Attachment 11; January 31, 

2007; OSA Ref ID: 102542 
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 Affidavit from Former Driller, Attachment 12; January 31, 2007; OSA Ref ID: 102543 

 Affidavit from Survivor, Attachment 13; January 26, 2007; OSA Ref ID: 102544 

 Affidavit from Survivor, Attachment 14; January 30, 2007; OSA Ref ID: 102561 

 Affidavit from Former Welder, Attachment 15; January 31, 2007; OSA Ref ID: 102792 

Thirteen miscellaneous documents provided as attachments, including scientific reports, journal 

articles, email correspondence, and one newspaper article: 

 Nevada Test Site—Review of Medical Surveillance, Summary of Radiation Exposure Date 

Analyses, Summary of Worker Demographics and Work History Information on Radiation 

Hazards, Attachment 1, various documents; Uploaded on February 6, 2007; OSA Ref ID: 102540

 NIOSH Responses to SC&A Comments: Draft Review of the NIOSH Site Profile for the Nevada 

Test Site, SCA-TR-TASK1-0006, Attachment 2; December 31, 2005; OSA Ref ID:102554

 Email Correspondence Regarding SC&A Findings on the NTS Site Profile, Attachment 8; 

February 23, 2006; OSA Ref ID: 102559

 The Resuspension Pathway for Nevada Test Site Workers, Rev. 03, Attachment 9, Lynn 

Anspaugh, SC&A; October 8, 2006; OSA Ref ID: 102560

 Test Site Workers’ Records Dumped, Attachment 16; Keith Rogers, Las Vegas Review-Journal

(Nevada); September 25, 2006; OSA Ref ID: 102545

 Movement of Radionuclides in Terrestrial Ecosystems by Physical Processes, Attachment 17; 

Lynn Anspaugh, Steven Simon, Gordeev Konstantin, Ilya Likhtarey, Reed Maxwell, and Sergei 

Shinkarev, Health Physics Vol. 82, No. 5; May 2002; OSA Ref ID: 102546

 Technical Basis for Dose Reconstruction, Attachment 18, Lynn Anspaugh; January 31, 1996; 

OSA Ref ID: 102547

 Introduction to Section II and Overview of Dose Reconstruction; Lessons Learned from Studies in 

the U.S., Attachment 19, Lynn R. Anspaugh; January 1997; OSA Ref ID: 102548

 A Comprehensive Dose Reconstruction Methodology for Former Rocketdyne/Atomics 

International Radiation Workers, Attachment 20, John Boice, Richard Leggett, Elizabeth Ellis, 

Phillip Wallace, Michael Mumma, Sarah Cohen, Bertrand Brill, Bandana Chadda, Bruce Boecker, 

Craig Yoder, and Keith Eckerman, Health Physics Vol. 90, No. 5; May 2006; OSA Ref ID: 

102549

 Risk Assessment of Soil-Based Exposures to Plutonium at Experimental Sites Located on the 

Nevada Test Site and Adjoining Areas, Attachment 21; David Layton, Lynn Anspaugh, Kenneth 

Bogen, and Tore Straume; June 1993; OSA Ref ID: 102550
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 Iodine-131 Fallout from Underground Tests, Attachment 22, E. A. Martell, Science Vol. 143, No. 

3602; January 10, 1964; OSA Ref ID: 102551

 Radionuclides in Surface Soil at the Nevada Test Site, Attachment 23; Richard McArthur; August 

1991; OSA Ref ID: 102552

 Performance Evaluation of LANL Environmental Radiological Air Monitoring Inlets at High Wind 

Velocities Associated with Resuspension, Attachment 24, John Rodgers, Piotr Wasiolek, Jeff 

Whicker, Craig Eberhart, Keith Saxton, and David Chandler; no date; OSA Ref ID: 102553

4.7 Other Technical Sources 

NIOSH has obtained the complete set of electronic bioassay records from NTS (NTS Bioassay Data, 

2009). These data are contained in four separate tables with the following titles: 

 dead_bio 

 Hddr_error 

 Hddr_master 

 Opdj_bioal 

These data have been included in the re-evaluation of the Nevada Test Site worker class in the 

revision to the original Evaluation Report (Rev.0). 

NIOSH also obtained and reviewed the Technical Basis for Internal Dosimetry at the Nevada Test 

Site, and NTS internal technical basis document implemented in 1993 that demonstrates NTS 

compliance with 10 C.F.R. 835 (NTS, 1993) 

5.0 Radiological Operations Relevant to the Proposed Class 

The following subsections summarize both radiological operations at NTS from January 1951 (start of 

operations) through the end of testing in 1992 and the information available to NIOSH to characterize 

particular processes and radioactive source materials. From available sources NIOSH has gathered 

process and source descriptions, information regarding the identity and quantities of each radionuclide 

of concern, and information describing both processes through which radiation exposures may have 

occurred and the physical environment in which they may have occurred. The information included 

within this evaluation report is intended only to be a summary of the available information. 

5.1 NTS Plant and Process Descriptions 

The Nevada Test Site is located in Nye County in southern Nevada, about 65 miles northwest of Las 

Vegas and currently encompasses approximately 3,500 km2

 (1375 mi2). The site was established in 

1951 and was the primary location for testing nuclear explosives in the continental United States 

between 1951 and 1992. The primary missions of NTS included atmospheric and underground 

nuclear testing, underground nuclear testing, safety testing, research into nuclear reactor and nuclear 

rocket development, Project Plowshare operations to explore peaceful uses of nuclear detonations, and 
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waste management operations (ORAUT-TKBS-0008-1). The NTS activities were unique and distinct 

from other DOE facilities in that they were experimental trials conducted in unique environments. 

The testing was strictly overseen, controlled, and monitored by a highly qualified staff of professional 

scientists, health and safety personnel, and support staff. The planning and preparation for each test 

was extensive. 

 

Above-ground nuclear weapons tests began on January 27, 1951. In addition to air drops, 

atmospheric testing included detonations from towers, detonations on the surface of the ground, and 

the use of helium-filled balloons to loft weapons above the ground. More than 100 atmospheric tests 

were conducted before the signing of the Limited Test Ban Treaty in August 1963. The Atmospheric 

Weapons Testing era at NTS has previously been evaluated and a class of workers at NTS during the 

January 27, 1951 through December 31, 1962 timeframe has previously been included in the Special 

Exposure Cohort (ORAUT-TKBS-0008-1). 

Since 1963, the United States has conducted all of its nuclear weapons tests underground in 

accordance with the terms of the Limited Test Ban Treaty. The final atmospheric tests at NTS were in 

July 1962. Complete containment of all nuclear weapons tests was a primary goal and a dominant 

consideration in nuclear test operations (ORAUT-TKBS-0008-1). 

Post-test drilling of the cavity formed after a detonation in a vertical drill hole was performed to 

retrieve debris samples, often within a day or two of the detonation. Reentry and mine-back 

operations related to tests in mined tunnels usually took place within days or weeks of a test. These 

operations took place in a confined underground environment where personnel entered the test tunnel 

and excavated up to the experiment chambers (ORAUT-TKBS-0008-1). 

Safety tests evaluated the safety of nuclear weapons in accident scenarios. The safety tests used 

plutonium, uranium, or mixtures of the two, dispersed by conventional explosives. Concurrent with 

and after these detonations, extensive studies were conducted to understand the dispersal and transport 

of these radionuclides in the environment, including uptake by plants and animals (ORAUT-TKBS0008-1). 

From 1959 to 1973, the Nuclear Rocket Development Station in Area 25 was used for a series of 

open-air nuclear reactor, nuclear engine, and nuclear furnace tests and for the High Energy Neutron 

Reactions Experiment. The goal of the Nuclear Rocket Engine Test program was to develop an 

operational nuclear rocket for space travel. Engine exhaust dispersed radioactive material from the 

core and cladding degraded during operation of the engine (ORAUT-TKBS-0008-1). 

Shallow borehole tests occurred between 1960 and 1968. Some of theses tests were related to safety 

studies and others were part of Project PLOWSHARE—to determine if nuclear detonations could be 

used as a method for excavation. The shallow tests resulted in some large ejection craters (ORAUTTKBS-0008-1). 

NTS has radioactive waste management activities in Areas 3 and 5. DOE disposes of bulk low-level 

waste in seven selected Area 3 subsidence craters that collectively comprise the Area 3 Radioactive 

Waste Management Site. This disposal began in the mid-1960s when DOE began removing scrap 

tower steel, vehicles, and other large objects that had been subjected to atmospheric testing. From 

1979 to 1990, large amounts of contaminated soil and other NTS debris were added to the craters. 
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The Area 5 waste management site uses pits and trenches for shallow land burial of low-level waste in 

standardized packaging (ORAUT-TKBS-0008-1). 

DOE adopted greater confinement burial (21 to 40 meters [70 to 120 feet] deep) for wastes that are not 

appropriate for near-surface disposal due to their radioactive exposure levels. Material was disposed 

from 1984 to 1989. The specific waste types included certain high-specific-activity, low-level waste 

(for example, fuel rod claddings and sealed sources, transuranic waste, and some classified material) 

(ORAUT-TKBS-0008-1). 

Table 5-1 summarizes the site activities. 

Table 5-1: NTS Development/Activities 

Years Areas Comments 

1951 - 1962 1, 2, 3, 4, 5, 7, 8, 

9, 11, 13, 18, 

Tonopah Test 

Range 

Approximately 106 atmospheric tests were conducted, several of which 

resulted in radioactive fallout detected in other areas, including outside NTS 

boundaries 

1951 - 1992 1, 2, 3, 4, 5, 6, 7, 

8, 9, 10, 11, 12, 

15, 16, 18, 19, 

20, 30, Tonopah 

Test Range 

Approximately 835 underground tests were conducted, including cratering 

experiments, borehole tests, and tunnel tests; several underground tests 

resulted in unplanned atmospheric radioactive releases 

1951 - Present Various Numerous tests and research projects have been conducted across NTS, 

including: conventional explosives testing, nuclear reactor development tests, 

radioactive waste disposal, radioactivity dispersal experiments, emergency 

response training exercises, and nuclear rocket propulsion experiments 

5.2 NTS Functions 

Nevada Test Site operations included the following discrete functions: 

 Atmospheric weapons testing 

 Safety testing 

 Big explosives experiments 

 Underground testing 

o Tests in vertical drill holes 

o Tests in mined tunnels 

o Routine tunnel operations 

 Nuclear reactor development testing 

 Shallow borehole testing 
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 Waste disposal 

o Crater disposal—Area 3 Radioactive Waste Management Site 

o Shallow land burial—Area 5 Low-Level Radioactive Waste Management Site 

o Greater confinement disposal—Area 5 Radioactive Waste Management Site 

 U1a Underground Complex 

 Analytical laboratory, research, and support activities 

Additional information regarding the areas and activities of NTS can also be found in ORAUTTKBS-0008-2. 

5.2.1 Atmospheric Weapons Testing 

U.S. above-ground nuclear weapons tests began on January 27, 1951, with the detonation of a 

1-kiloton (kt) air-dropped weapon over Frenchman Flat. More than 100 atmospheric tests occurred 

before the signing of the Limited Test Ban Treaty in August 1963. 

Radioactivity from atmospheric tests was dispersed by three primary mechanisms: throwout, base 

surge, and fallout. Typical radionuclides formed during atmospheric testing included isotopes of 

strontium, cesium, barium, tritium, and iodine. Of these, strontium-90 and cesium-137 are of the most 

concern because of their longer half-lives of 28 and 29 years, respectively (ORAUT-TKBS-0008-2).

5.2.2 Safety Testing 

Safety tests evaluated the safety of nuclear weapons in accident scenarios. The safety tests involved 

plutonium, uranium, or mixtures of the two, dispersed by conventional explosives. Extensive studies 

were conducted, concurrent with and after these detonations, to understand the dispersal and transport 

of these radionuclides in the environment. These studies were documented in a benchmark series of 

papers by the Nevada Applied Ecology Group, a panel of scientists chartered to investigate the effects 

of testing at NTS. As a result of the safety tests, the primary radionuclide contaminants at NTS are 

plutonium, uranium, and americium, with lesser amounts of cesium, strontium, and europium 

(ORAUT-TKBS-0008-2). Extensive research into the mobility of radionuclides has found that wind 

can transport such contaminants and concentrate them in mounds around desert shrubs and that water 

can cause plutonium to migrate deeper into the soil over time. At present, the radionuclides are 

relatively immobile unless the soil is disturbed. Evidence of “wind-driven” contamination is low. 

Heat of initial blast, soil bonding and weathering, and rockiness of native soil prevent deep migration 

(Allen, 1995). 

5.2.3 Big Explosive Experiments 

The Big Explosives Experimental Facility is in north-central Area 4 of NTS. The area contains seven 

underground structures previously associated with atmospheric testing; one set of unidentified 

stanchions that might have been associated with atmospheric testing; the BREN Tower foundations 

and stanchions; and the Japanese Village complex. The area also has the U-4ad drill hole and drill 

sump, the U-4af exclusion zone, and a white silicified volcanic core reduction flake. Most of these 

structures were abandoned as atmospheric testing ended. Two of the buried structures, Bunkers 4-300 

and 4-480, have been modified to accommodate modern hydrodiagnostic equipment to serve as a 
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hydrodynamic test facility for detonations of very large conventional high explosive charges and 

devices. Some detonations at the Big Explosives Experimental Facility involved depleted uranium 

(ORAUT-TKBS-0008-2). 

5.2.4 Underground Testing 

Since 1963, the United States has conducted all of its nuclear weapons tests underground in 

accordance with the terms of the Limited Test Ban Treaty. Complete containment of all nuclear 

weapons tests was a dominant criterion in the test design for nuclear test operations. Various methods 

were used for emplacing nuclear test devices to contain the explosion. The most common method was 

to place a test device at the bottom of a vertical drill hole. Another method was to place a test device 

in a tunnel mined horizontally to a location sufficiently deep to provide containment. There were two 

types of tests in vertical drill holes: lower-yield devices in relatively shallow holes in the Yucca Flats 

area (Areas 1 through 10) and higher-yield devices in deeper holes on Pahute Mesa (Areas 18 through 

20) (ORAUT-TKBS-0008-2). 

The following paragraphs describe processes associated with nuclear weapons tests in vertical drill 

holes and mined tunnels. 

5.2.4.1 Tests in Vertical Drill Holes

There were two types of tests in vertical drill holes: lower-yield devices in relatively shallow holes in 

the Yucca Flat area (Areas 1 through 10) and higher-yield devices in deeper holes on Pahute Mesa 

(Areas 18, 19, and 20). Tests at the Yucca Flat and Pahute Mesa sites had the same general 

requirements, but differed in the magnitude of the operations. Post-test drilling of the cavity formed 

after a detonation in a vertical drill hole was performed to retrieve debris samples. The post-test hole 

was as small in diameter as possible and was drilled at an angle to allow the drill rig to be positioned 

safely away from the surface at ground zero. It was possible to encounter high gas pressures in the 

cavity because the drillback was often performed within a day or two of the detonation (ORAUTTKBS-0008-2). A procedure known as gas blocking was applied to control this type of pressure 

release. 

5.2.4.2 Tests in Mined Tunnels

Tunnel tests evaluated the effects of nuclear weapons explosions, thermal radiation, blast, shock, Xrays, and gamma rays on military hardware, such as communication equipment, rocket nosecones, and 

satellites. A number of tunnels have been mined into Rainier Mesa, in which most Department of 

Defense horizontal-line-of sight exposure experiments occurred. In particular, the N-, P-, and TTunnel complexes were extensively developed during the past several decades. The Department of 

Defense currently operates a high explosives research and development tunnel in Area 12. 

Of the 61 underground nuclear tests in Area 12 between late 1957 and 1992, only two were in drilled 

holes, the 59 other tests were in mined tunnels. By the early 1990s there was only one active tunnel in 

use (ORAUT-TKBS-0008-2). 
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5.2.4.3 Routine Tunnel Operations

Routine tunnel operations included the potential for personnel exposure to fission or activation 

products from previously conducted tests in the tunnel complex. These radioactive materials could 

also be carried by water, seeping through faults and fissures to reenter the working areas (Allen, 

1995). Personal communication on September 12, 2007 with the former Health and Safety Manager 

of NTS indicated that Radiation Monitors conducted radiation surveys and air monitoring to evaluate 

the radiation conditions in the tunnel before allowing workers to enter for routine operations. The 

protocols required tunnels to be vented and air monitoring be conducted during routine tunnel 

operations. 

Reentry and Mineback Operations: Reentry and mineback operations related to tests in mined tunnels 

usually took place within days or weeks of an underground test, but could be conducted at any time 

after a test. There were two exposure scenarios during reentry and minebacks. The first scenario was 

based on a loss of containment in the drilling or coring operation; this could occur during the routine 

drilling operations or be caused by a failure of containment equipment. The radionuclides of concern 

for this pathway were manganese-54, strontium-90, yttrium-90, ruthenium-103, rhodium-106, iodine131, iodine-133, cesium-127, and tantalum-182 (Allen, 1995).

The second exposure scenario involved the possibility of fission or activation products entering the 

working areas of the tunnels by migrating through fissures in the rock, by escaping through line-ofsight pipes when they were opened to remove experiment equipment and samples. The radionuclides 

of exposure concern for this pathway were cobalt-60, antimony-124, iodine-131, iodine-133, and 

cesium-137 (Allen, 1995). 

Radioactive Releases Resulting from Nuclear Weapons Testing: Containment of underground nuclear 

explosions was a process that continually evolved through learning, experimentation, and experience. 

Radioactive releases resulting from nuclear weapons testing included operational releases, late-time 

seeps, and controlled tunnel purging. 

Operational releases were small releases of radioactivity resulting from the operational aspects of 

vertical drill-hole tests. Activities that often resulted in operational releases included drilling back 

down to the location of the explosion to collect core samples, collecting gas samples from the 

explosion, and sealing the drillback holes (OTA, 1989). 

Late-time seeps were small releases that occurred days or weeks after a test, when gases diffused 

through pore spaces of the overlying rock and were drawn to the surface by decreases in atmospheric 

pressure. 

Controlled tunnel purging was an intentional release of radioactive material for the purpose of 

recovering experimental equipment and ventilating test tunnels. During a controlled tunnel purging, 

gases from the tunnel were filtered, mixed with air to reduce the concentration, and released over time 

when weather conditions were favorable for dispersion into sparsely populated areas (OTA, 1989). 
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Successful containment was defined as no radioactivity detectable offsite and no unanticipated release 

of radioactivity onsite. By definition, there have been containment failures on four occasions since 

1970 (OTA, 1989). Table 2-6 of ORAUT-TKBS-0008-2 includes every instance (for both announced 

and unannounced tests) where radioactive material reached the atmosphere under any circumstances 

whatsoever from 1971 through 1988. The bottom portion of Table 2-6 summarizes underground tests 

prior to 1971 and provides a comparison with other releases of radioactive material. 

Operational Releases and Tunnel Purging: Past underground tests formed pockets of radioactive 

contamination around each underground test site. The source term includes many short- and longlived radionuclides. For example, for atmospheric testing of a 1-kt nuclear weapon, an initial release 

of 41 billion Ci decays to about 10 million Ci in just 12 hours. The quantity of radioactivity 

remaining from a 1-kt underground detonation 180 days after detonation is about 45,000 Ci (including 

18,570 Ci of tritium). However, there is considerable uncertainty concerning these estimates. For 

example, the actual tritium activity after 180 days could range from 5,570 to 55,770 Ci (ORAUTTKBS-0008-2).

With regard to tunnel tests, purging gases from the tunnel occasionally resulted in releases of 

radioactivity, and contaminated water drained from the tunnels into containment ponds (Bechtel 

Nevada, 2002). While the tunnel complex was being secured prior to detonation of the nuclear 

device, the ventilation line was disconnected at each containment plug and the penetration through the 

plug was sealed. Thus, it was necessary to reenter the tunnel to reestablish ventilation through the 

various containment plugs. When radioactive gases were present in a portion of the complex, it 

became necessary to purge these gases from the tunnel. The major potential for release of radioactive 

materials to the atmosphere existed during these purging operations. The purging resulted in release 

of noble gases (krypton-85, krypton-85m, krypton-86, xenon-131m, xenon-133, xenon-133m, and 

xenon-135) and small quantities of iodine-131 and iodine-133. A release during this phase of the 

operation was typically of the order of 100 Ci or less of noble gases, with microcurie or millicurie 

quantities of radionuclides. Reentry drilling produced dust that was removed from the reentry heading 

by the tunnel ventilation system. This dust contained fission and activation products produced by 

neutron activation of the horizontal line-of-sight pipe. These releases were in the millicurie range 

(Black, 1995). 

Unexpected Releases of Radioactivity: Although over 90% of all nuclear weapons tests occurred as 

predicted, sometimes the unexpected occurred. In some cases, the failure resulted in the loss of 

experimental equipment or required the controlled ventilation of a tunnel system to recover 

equipment. In even fewer cases (3%), the failure resulted in the unintentional release of radioactive 

material into the atmosphere. NTS testing was conducted as part of the scientific process of observing 

and determining the results of radioactive detonations bounded by particular conditions. NTS tests 

were thoroughly planned and monitored to achieve the necessary information that the test was 

designed to derive. Ten of these tests resulted in unexpected outcomes. Four of the ten tests resulted 

in the release of detectable levels of radioactivity off the NTS grounds: DES MOINES, June 13, 

1962; BANEBERRY, December 18, 1970; DIAGONAL LINE, November 24, 1971; and RIOLA, 

September 25, 1980 (ORAUT-TKBS-0008-1).
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5.2.5 Nuclear Reactor Development Testing 

A number of activities occurred at the Nuclear Rocket Development Station in Area 25. From 1959 

through 1973, Area 25 was used for a series of open-air nuclear reactor, nuclear engine, and nuclear 

furnace tests and for the High Energy Neutron Reactions Experiment. Equipment and facilities still 

remain from some of these activities, and there are some limited areas of contaminated soil. The total 

estimated inventory of radionuclides remaining in the soil in this area is about 1 Ci (ORAUT-TKBS0008-2). The primary soil contaminants are enriched uranium, strontium, cesium, cobalt, and 

europium. Because of aging and weathering, these materials have become fairly fixed. 

Total releases by all tests amounted to about 834,000 Ci (ORAUT-TKBS-0008-2). As noted 

previously, the radionuclides cobalt-60, strontium-90/yttrium-90, cesium-137, and europium-152 are 

primarily of concern for dose in this area. When entering into the rocket test areas, personnel wore 

whole-body thermoluminescent dosimeters (Allen, 1995). 

5.2.6 Shallow Borehole Testing 

Shallow borehole tests occurred between 1960 and 1968. Some of these tests were safety-related 

while others were conducted as part of Project PLOWSHARE to determine if nuclear detonations 

could be used as a method of excavation. The shallow tests resulted in the development of some large 

ejection craters, most notably the SEDAN crater in the northern end of the Yucca Flat testing area. 

SEDAN, a 104-kt nuclear device detonated 194 m (635 feet) underground, displaced about 1.2 x 107

tons of earth, and created a crater 390 m (1,280 feet) in diameter and 98 m (320 feet) deep. The 

estimated remaining inventory of surface radioactivity at the SEDAN crater is 344 Ci. The total 

estimate for all releases from shallow borehole tests to the surface soil horizon at NTS is 2,000 Ci. 

The radionuclides of concern resulting from shallow borehole tests include isotopes of americium, 

cesium, cobalt, europium, plutonium, and strontium (ORAUT-TKBS-0008-2). 

5.2.7 Waste Disposal 

The following paragraphs describe processes associated with crater disposal, shallow land burial, and 

greater confinement disposal. 

5.2.7.1 Crater Disposal – Area 3 Radioactive Waste Management Site

DOE disposes of bulk low-level waste in seven selected Area 3 subsidence craters that, collectively, 

comprise the Area 3 Radioactive Waste Management Site. This activity began in the mid-1960s when 

DOE began removing scrap tower steel, vehicles, and other large objects that had been subjected to 

atmospheric testing. From 1979 to 1990, large amounts of contaminated soil and other NTS debris 

were added to the craters. As of 1996, approximately 1,250 Ci had been disposed of in the Area 3 

subsidence craters (ORAUT-TKBS-0008-2). 

Because the low-level Area 3 Radioactive Waste Management Site is located where the surrounding 

surface soil has been contaminated by past nuclear tests, the resuspension of this soil by wind or 

vehicular activity results in the detection of above-background levels of plutonium in air samples 

collected inside and outside the perimeter fence (Bechtel Nevada, 2002). 
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5.2.7.2 Shallow-Land Burial – Area 5 Low-Level Radioactive Waste Management Site

In 1961, the Area 5 Radioactive Waste Management Site was established for the shallow-land 

burial/disposal of standard packaged low-level waste, low-level mixed waste, and classified low-level 

waste from both on- and offsite generators. The category of low-level waste includes material that is 

“classified” because of its physical shape or specific composition. Classification creates a need for the 

use of separate disposal units that are controlled with additional security measures. The waste area at 

Area 5 consists of 23 landfill cells (pits and trenches), 13 greater confinement disposal boreholes, and 

the transuranic waste storage pad.

Approximately 500,000 Ci of low-level waste had been disposed of in Area 5 pits and trenches by 

1996. High-specific-activity wastes were disposed of in the greater confinement disposal units 

(ORAUT-TKBS-0008-2). 

5.2.7.3 Greater Confinement Disposal – Area 5 Radioactive Waste Management Site

NTS adopted greater confinement burial (21 to 40 m [70 to 120 feet] deep) for wastes that were not 

appropriate for near-surface disposal due to their radioactive exposure levels. Material was disposed 

of in these disposal units from 1984 to 1989. Specifically, these waste types include certain highspecific-activity, low-level waste (for example, fuel rod claddings and sealed sources), transuranic 

waste, and some classified material. The developed waste area in the Area 5 Radioactive Waste 

Management Site includes 13 greater confinement disposal boreholes. 

As of 1996, approximately 9.3 x 106

 Ci of high-specific-activity waste, primarily tritium, had been 

disposed of in greater confinement disposal units in Area 5 (ORAUT-TKBS-0008-2). 

5.2.8 U1a Underground Complex 

The U1a Complex is a mined underground complex in Area 1 that is available for dynamic 

experiments (including subcritical experiments involving special nuclear material) and hydrodynamic 

tests that cannot be conducted above the ground because they might contain hazardous materials. 

Initial work on the U1a Complex began in the late 1960s with the mining of the U1a shaft to a depth 

of 305 m (1,000 feet) for a nuclear test, but the shaft was not used. Further work took place in the 

1980s and early 1990s to develop a complex that could be used to perform experiments likely to 

remain subcritical. The U1a Complex included a drilled hole (U1g) and connecting mined tunnels. 

The LEDOUX nuclear test, with a yield of less than 20 kts, was conducted in 1990 in a drift in this 

tunnel Complex. LEDOUX was contained to prevent radiological releases to the rest of the Complex 

and the surface environment (ORAUT-TKBS-0008-2). 
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5.2.9 Analytical Laboratory, Research, and Support Operations 

Analytical laboratory, research, and support activities have been, and continue to be, conducted for 

various projects, which include: 

 Containment ponds (tritium) 

 Radiological Analysis Laboratories (samples containing tritium, radioiodines, or noble gases)—

Mercury: Building 652; Area 6: Buildings CP-95A, CP-50, and the Device Assembly Facility 

 Analytical Services Laboratory (tritium, krypton-85, and iodine-129)—Building 650 

 Los Alamos National Laboratory (xenon-133, iodine-131, and tritium)—Mercury: Building 701 

 Radiographic operations (iridium-192 and cobalt-60) 

 Radiochemistry and Counting Laboratories (low-level radioactive sources used as tracers for 

instrument calibration) 

 Contaminated surface soils (cesium, americium, plutonium, and/or tritium) 

 Well-logging operations (cobalt-60, iodine-131, cesium-137, radium-226, thorium-228, americium241, and francium-252) 

 Treatability Test Facility—testing technologies to be used for soil decontamination (transuranic 

materials) 

 Decontamination Facility (various radionuclides) 

 Radiation Instrument Calibration Facilities (cobalt-60, strontium-90, yttrium-90, cesium-137, 

radium-226, thorium-227, thorium-228, americium-241, and plutonium-beryllium neutron sources) 

 Radioactive Source Storage Areas (various sealed sources) 
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5.2.10 Summary of Key NTS Facilities 

Table 5-2 summarizes key operations as well as the areas and dates of operation. 

Table 5-2: Key NTS Areas, Operations, and Dates of Operation 

Table 5-1 spans two pages. 

Areas Key Operations Dates 

1-10 and 18-20 

Drillback Operations: A post-shot hole was usually drilled to the point of the 

explosion to retrieve debris samples. There was potential for exposure to gaseous 

and particulate fission and activation products including krypton-85, iodine-131, 

iodine-133, xenon-133m, and cesium-137 (Allen, 1995).

1961 - 1992 

12 

Reentry and Mineback Operations: After underground tests, a reentry crew was 

dispatched to the site to retrieve data and note the condition of equipment. 

Reentries had the potential to cause significant external and internal radiation 

exposures. The radionuclides of concern for reentry and mineback operations in 

the event of loss of containment include manganese-54, strontium-90, yttrium-90, 

ruthenium-103, rhodium-106, iodine-131, iodine-133, cesium-127, and tantalum182 (Allen, 1995). Another radiation safety concern is the migration of fission or 

activation products cobalt-60, antimony-124, iodine-131, iodine-133, and cesium137 into the working areas of the tunnels.

1957 - 1992 

12 

Routine Tunnel Operations: Routine tunnel operations potentially exposed 

personnel to fission or activation products that remained from tests conducted 

previously in the tunnel complex. Experience has shown that the external dose 

levels in routine tunnel work areas were very low. The principal radionuclides of 

external dose concern were the fission products strontium-90/yttrium-90 and 

cesium-137 (Allen, 1995).

1957 - 1992 

6 

Decontamination Facility: Equipment, materials, PPC, and devices used in 

nuclear weapons testing operations sometimes became contaminated with 

radioactive material and had to be decontaminated on location or were transported 

to the decontamination facility in Area 6. 

1961 - 1992 

25-26 

Nuclear Rocket Development: This area was used for a series of open-air 

nuclear reactor, nuclear engine, and nuclear furnace tests and for the High Energy 

Neutron Reactions Experiment. The primary soil contaminants are enriched 

uranium, cobalt-60, strontium-90/yttrium-90, cesium-137, and europium-152.

1959 - 1973 

27 Device Assembly: This is where nuclear devices were assembled and contained 

before delivery to the event site. - 

1-10, 12, and 18-

20 

Experiment Emplacement: The nuclear explosive and measurement devices 

were moved to the hole and lowered into the detonation position, along with 

diagnostic materials and instrumentation cables. The assembly was placed on a 

set of fracture-safe beams that spanned the opening. Any auxiliary equipment 

was lowered into the hole and the area was secured. 

1961 - 1992 

1 and 6 

Laboratories and Research and Support: The U1a Complex is a mined 

underground complex in Area 1 that is available for dynamic experiments 

(including sub-critical experiments involving special nuclear material) and 

hydrodynamic tests that cannot be conducted above the ground because they 

might contain hazardous materials. Radiological analyses were conducted in 

laboratories in Building 652 (Mercury) and Building CP-95A, Building CP-50, 

and the Device Assembly Facility in Area 6.

- 
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Table 5-2: Key NTS Areas, Operations, and Dates of Operation 

Table 5-1 spans two pages. 

Areas Key Operations Dates 

3 and 5 

Waste Management: Areas 3 and 5 contain Radioactive Waste Management Site 

(RWMS) Areas for the disposal of low-level radioactive waste. Area 5 contains 

sites for storage of transuranic and mixed transuranic wastes, as well as the 

Greater Confinement Disposal Test Unit and 12 accompanying boreholes (only a 

few contain any waste). Disposal occurs in pits and trenches; concrete pads 

provide temporary storage of certain wastes. Area 5 is for packaged waste 

disposal only. The Waste Examination Facility (WEF) houses a HEPA-filtered 

glovebox used to examine and repack transuranic waste drums.

1961 - Present 

Note: Operations span the history of NTS; however, specific start dates are unknown 

5.3 Radiological Exposure Sources from NTS Operations 

The potential for both internal and external radiation exposure existed at NTS. While the primary 

materials associated with the testing at NTS were uranium and plutonium, there were significant 

exposure potentials to various fission and activation products. Due to the nature of operations at NTS 

(unlike most other DOE facilities, there was no uranium or plutonium production or machining at 

NTS), when NTS workers received an exposure, it was most likely to be an acute event exposure 

rather than long-term chronic doses. 

After 1962, the United States conducted all of its nuclear weapons tests underground, in order to 

contain the explosion and the byproducts of the testing. Achieving full containment was a continually 

evolving process and various types of releases occurred throughout the program. 

Although atmospheric weapons testing occurred at NTS prior to 1963, the longer-lived radionuclides 

that were deposited into the NTS environment as a result of the atmospheric weapons testing persisted 

into the period of evaluation and must be taken into account. Residual contamination for atmospheric 

testing is present in Areas 1, 2, 3, 4, 7, 8, 9, and 10 of NTS and on Buckboard Mesa in Area 18. All 

areas except Areas 22, 23, and 27 have some monitoring and restrictions as a result of these past tests 

(Allen, 1995). Area 22 includes the main entrance to NTS and a reserved zone providing a buffer 

between non-defense related research, development, and testing activities. Area 23 is also a reserved 

zone in the southeastern portion of NTS and containing Mercury, the largest operational support 

complex onsite. Area 27 is a Critical Assembly zone in the south central part of NTS principally 

occupied by assembly bays, storage magazines, storage magazines, and three radiography buildings. 

No nuclear explosive tests occurred in Area 27 (ORAUT-TKBS-0008-2, page 20). These areas were 

monitored and had no access restrictions resulting from contamination. 
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5.3.1 Alpha Particle Emissions 

The primary alpha particle-emitting isotopes at NTS vary from area to area depending on the 

operations. Table 5-3 below lists the alpha-emitting radionuclides of concern for NTS. 

Table 5-3: NTS Alpha-Emitting Radionuclides 

Isotope Major Radiation Energies (MeV) 

Actinium-227 4.95(1.2%), 4.86 (0.18 %) 

Americium-241 5.49 (85%), 5.44 (13%) 

Americium-243 5.28 (87%), 5.23 (11.5%) 

Californium-252 6.12 (82%), 6.08 (15%) 

Curium-244 5.81 (77%), 5.77 (23%) 

Neptunium-237 4.78 (75%), 4.65 (12%) 

Plutonium-238 5.50 (72%), 5.46 (28%) 

Plutonium-239 5.16 (88%), 5.11 (11%) 

Plutonium-240 5.17 (76%), 5.12 (24%) 

Plutonium-241 4.90 (0.0019%) 4.85 (0.0003%) 

Plutonium-242 4.90 (76%), 4.86 (24%) 

Radium-226 4.78 (95%), 4.60 (6%) 

Thorium-228 5.43 (71%), 5.34 (28%) 

Thorium-230 4.68 (76%), 4.62 (24%) 

Thorium-232 4.01 (76%), 3.95 (24%) 

Uranium-233 4.82 (83%), 4.78 (15%) 

Uranium-234 4.77 (72%), 4.72 (28%) 

Uranium-235 4.58 (8%), 4.4 (57%), 4.37 (18%) 

Uranium-238 4.20 (75%), 4.15 (25%) 

5.3.2 Beta Radiation Fields 

There are about 90 possible fission fragments resulting from nuclear fission. These 90 fragments 

decay through three stages, on average, to yield a total of about 250 individual fission-produced 

radionuclides, most of which are beta particle emitters. Many of these beta-emitting fission product 

radionuclides have very short half-lives – on the order of a few seconds or less – and quickly decay 

into other nuclides; thus, they were not a direct source of exposure to the proposed class. Beta 

emission occurs over a distribution of energies ranging from zero to a maximum value; that maximum 

value is commonly used to characterize the spectrum. Table 5-4 below lists the isotopes of concern at 

NTS. The maximum energy is indicated in the right column. Where there is a second significant, 

higher energy range that also occurs as a result of the decay of the isotope, it is indicated in the chart, 

along with the fraction. The average energy of a beta spectrum is typically about one-third of the 

maximum energy. 
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Table 5-4: NTS Beta-Emitting Radionuclides 

Isotope Major Radiation Energies (MeV) 

Actinium-227 0.046 

Barium-140 1.02 

Cerium-141 0.581 

Cerium-143 1.39 

Cerium-144 0.31 

Cesium-134 .662 

Cesium-137 1.176 (7%), 0.514 

Europium-152 1.48 

Europium-154 1.85 (10%), 0.87 

Europium-155 0.25 

Iron-59 1.57 (0.3%), 0.475 

Mercury-203 0.214 

Iodine-131 0.806 (0.6%), 0.606 

Iodine-133 1.27 

Iodine-135 1.4 

Iridium-192 0.67 

Molybdenum-99 1.23 

Sodium-22 0.545 

Sodium-24 1.389 

Nickel-63 0.067 

Promethium-147 0.224 

Plutonium-241 0.021 

Rhodium-100 0.74 (positron) 

Rhodium-106 3.54 

Ruthenium-103 0.70 (0.3%), 0.21 

Ruthenium-106 0.039 

Antimony-124 2.31 

Antimony-125 0.61 

Strontium-89 1.463 

Strontium-90 0.546 

Tantalum-182 1.71 (0.3%), 0.522 

Telluruim-132 0.22 

Yttrium-88 0.76 (positron) 

Yttrium-90 2.27 

Yttrium-91 1.545 

Zirconium-95 0.89 (2%), 0.396 

Zirconium-97 1.91 
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5.3.3 Neutron Exposures 

A small fraction of the workers at NTS had the potential for neutron exposure. For workers with a 

possibility of neutron exposure, personnel neutron dosimeters were used to monitor exposure 

(ORAUT-TKBS-0008-6). Potential sources of neutron exposure at NTS included: 

 Direct production from a nuclear detonation, 

 Spontaneous fission and subcritical multiplication in fissile materials (e.g., uranium-235, 

plutonium-239), 

 Isotopic sources such as initiators and calibration sources, and 

 Reactor testing. 

Table 5-5 lists NTS areas and activities with potential neutron exposure to NTS workers. 

Table 5-5: NTS Areas and Activities with Potential Neutron Exposure 

Area Activity Neutron Sources Beginning Final 

5 Low-level waste storage Transuranic waste Before 1962 Present 

6 Nuclear device assembly Fission neutrons Before 1962 1992 

25 NRDS and BREN tower calibrations and 

operation 

Fission neutrons and neutron 

sources californium-252, PuBe*

and AmBe+

1966 1973 

26 PLUTO Reactor (nuclear-powered ramjet 

engine) research 

Fission neutrons and neutron 

sources californium-252, PuBe*

and AmBe +

Mid 1960 Late 1960 

27 Nuclear explosive assembly using special 

nuclear material 

Fission neutrons and neutron 

sources californium-252, PuBe*

and, AmBe+

Before 1982 1975 

Various Down-hole well-logging 

*

PuBe or californium-252 

isotopic sources Before 1962 Present 

Various Neutron detection instrument calibration 

*

PuBe or californium-252 

isotopic sources Before 1962 Present 

Notes: 

*

Plutonium-238 and beryllium 

+Americium-241 and beryllium 

Exposure of NTS workers to neutrons from nuclear detonations, while theoretically possible, was 

realistically infeasible. The closest workers (test personnel) were at CP-2, and later CP-1 in Area 6, 

more than 6 km from the atmospheric test locations (ORAUT-TKBS-0008-6). If an individual was 

more than 6 km from a detonation site, the neutron dose would have been less than 1 mrem (ORAUTTKBS-0008-6, page 39). Negligible neutron exposures were possible in the vicinity of devices being 

tested or other significant quantities of fissionable materials. The few individuals associated with 

final assembly, arming, and firing test weapons would have had potential for neutron exposure. 
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During assembly operations, trained personnel were in proximity with the device components and 

involved with direct hands-on manipulation of the pits. These workers may have been exposed to 

neutrons emanating from the pits. Most or all workers involved in final assembly, arming, and firing 

of test devices would have been national laboratory employees and monitored as visitors to NTS 

(ORAUT-TKBS-0008-6, page 40). 

The most significant potential source of neutron exposure was from isotopic neutron sources such as 

plutonium-238 and beryllium or californium-252. These sources were used in specific activities such 

as instrument calibration and well-logging. Only a few documented, highly trained and specialized 

individuals had access to such sources (ORAUT-TKBS-0008-6). 

The final source of potential neutron exposure was from reactor test operations. Test operations 

occurred in specific areas (Areas 25 and 26) designated for that purpose. A concrete building, used as 

the control point for reactor operation testing, was located approximately two miles from the test cell. 

Again, as with access to neutron isotopic sources, only a few, highly trained and specialized 

individuals had access to these areas. The potential for significant neutron exposure due to reactor 

operations was further mitigated by the fact that the neutron exposures would have been accompanied 

by much greater gamma exposures, which were utilized as the governing factor for exposure control 

(ORAUT-TKBS-0008-6). Additional information regarding reactor operations is available in 

ORAUT-TKBS-0008-6. 

5.3.4 Photon Exposures 

The residual radiation field following detonation of a nuclear weapon consists of radiation from 

fission products, activation products, and unfissioned uranium or plutonium. For more information 

regarding the specific radionuclides of concern, see ORAUT-TKBS-0008-2, Table 2-2. Although the 

residual radiation intensity depends on a number of factors that can vary from test to test, relatively 

few radionuclides, common to all tests, are the primary contributors to the photon spectrum. The 

relative abundance of each radionuclide determines the spectrum. The photon field at NTS is 

primarily due to photons with energies between 100keV and 2 MeV. There is very little contribution 

from photons with energies less than 100 keV, with the exception of scattering from large area 

sources. In those cases, the scattered radiation was determined to have energy of approximately 75 

keV and to have contributed as much as 10% of the overall photon spectrum. Exposures at NTS were 

largely to photons with energies greater than a few hundred KeV (ORAUT-TKBS-0008-6, page 35-

36). 

6.0 Summary of Available Monitoring Data for the Proposed Class 

The primary sources of monitoring data for this evaluation include the NIOSH SRDB and NOCTS. 

NIOSH is aware of the Historical Records Center (HRC) database maintained by Bechtel Nevada and 

the Radiation Exposure Monitoring System (REMS) electronic dosimetry system for available internal 

and external monitoring data. Much of NIOSH’s NOCTS database claimant exposure data were 

retrieved from these sources by DOE Nevada in response to claim data requests. 
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NTS used facility and individual worker monitoring methods to measure and control radiation 

exposures. NTS hardcopy radiation exposure records and film from dosimeters are available. There 

was a considerable effort to consolidate all NTS and Pacific Proving Grounds dosimetry records in 

what was originally called the Dosimetry Research Project (DRP), now known as the Nuclear Testing 

Archive. The records are under the control of DOE. In addition to site records, records were retrieved 

from Los Alamos National Laboratory and various archives when it became evident that data were 

missing (Personal Communication, 2005). 

The SRDB contains copies of many NTS records. Reviews of these records identified personal 

monitoring data (e.g., film badge exposure results, thermoluminescent dosimeter monitoring results, 

bioassay results) and area monitoring data. 

Since Rev. 0 of this Evaluation Report was published in September 2007 (NIOSH, 2007), NIOSH has 

obtained the complete set of electronic bioassay records from NTS (NTS Bioassay Data, 2009). 

6.1 NTS Internal Monitoring Data 

The primary focus of the dosimetry program at NTS was external monitoring, particularly during 

atmospheric testing. The assumption, based on animal data showing that internal dose due to 

inhalation was small in comparison to external dose, was that by controlling the external dose, the 

internal dose would be limited. Early bioassay screens (e.g., nasal swabs, respirator swipes, and urine 

samples) were performed if contamination was found or suspected. A positive nasal swab initiated the 

collection of a urine sample, which was analyzed for tritium, gross beta, and gross gamma. As the 

bioassay program matured, urine samples were collected in a routine, random screening process. By 

1961, members of Rad-Safe, miners, drillers, and tunnel workers were some of the workers included 

in the routine bioassay program (REECo, 1961). Routine bioassays at NTS included quarterly urine 

samples, annual whole-body counts, and new/termination whole-body counts (Allen, 1993; Arent, 

2004). Non-routine bioassay types included job-specific and occurrence response (University of 

California, 1965; LRL, 1961; Allen, 1993). Examples of non-routine bioassays include the following 

analyses: 

 Tritium or gamma scan 

 Gross fission product (beta) 

 Specific radionuclides 

Whole-body counts, lung counts, thyroid counts, and biological sampling were performed as soon as 

practicable after a suspected intake (Allen, 1993). Specific examples include: 

 Lung counts following a suspected intake of thorium, uranium, or a transuranic 

 Whole-body counts for detecting most gamma-emitting fission and activation products 

 Thyroid counts for suspected radioiodine uptakes 

 Urine bioassay for detection of pure beta emitters such as strontium-89 and strontium-90 

 Urine and feces sampling, as well as lung and whole-body counting to detect and assess intakes of 

actinides 

Details regarding the various analyses used and the associated minimum detectable activities are 

presented in ORAUT-TKBS-0008-5. 
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Since Rev. 0 of this Evaluation Report was published in September 2007 (NIOSH, 2007), NIOSH has 

obtained the complete set of electronic bioassay records from NTS (NTS Bioassay Data, 2009). 

These data are contained in four separate tables with the following titles: 

 dead_bio 

 Hddr_error 

 Hddr_master 

 Opdj_bioal 

The "dead_bio" table contained results only through 1963. Because these data were collected during 

the period of a previously-established SEC class (SEC-00055), they were not evaluated further. Data 

from the other tables were extracted and evaluated to eliminate duplicates, perform unit conversion, 

and identify potential data issues. Analysis types were combined by radionuclide or group of 

radionuclides. Only urine sample data were judged adequate to form the basis for a co-worker study, 

with the exception of plutonium fecal results for the time period when a routine fecal program was in 

place. Urinalysis data were found for tritium, beta, gamma, and plutonium. The chart in Figure 6-1 

depicts the number of bioassay analyses in the database between 1970 and 1994, the years for which 

the data were most abundant. 

NTS Urine Bioasay Samples

0

1000

2000

3000

4000

5000

6000

7000

8000

1971

1973

1975

1977

1979

1981

1983

1985

1987

1989

1991

1993

Plutonium

Tritium

Gamma

Beta

Figure 6-1: NTS Urine Bioassay Samples, 1970-1994 

The results for each bioassay sample were recorded by employee name and social security number; 

however, no data were located that indicated where the employees worked, their job titles, or why the 

samples were taken. After review of the information available in the NTS electronic database, 

NIOSH has reconsidered its position on its ability to reconstruct NTS internal doses. 
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6.2 NTS External Monitoring Data 

For nearly three decades, from the start of operations in January 1951 until 1987, personnel 

dosimeters with photographic emulsions of various types and in various holders (i.e., film badges) 

were primarily used as the external dosimeter at NTS. The terms “film badge,” or “film badge 

dosimeter,” refer to the entire dosimeter issued to personnel, which typically consisted of a 

dental-sized film packet housed in a holder of varying configurations, and was designed to measure 

radiation and improve the response characteristics of the film badge. Although a number of different 

film types were used for dosimetry at NTS, they generally had similar characteristics and responses to 

beta and photon radiation. Uncertainties in dosimetry with this film are largely, if not exclusively, the 

result of external factors rather than differences among the films (ORAUT-TKBS-0008-6). 

Starting in February 1966, thermoluminescent dosimeters were used at the Nuclear Rocket 

Development Station (NRDS) as part of the effluent monitoring program. These dosimeters contained 

a calcium fluoride phosphor bound to a helically wound wire in an evacuated glass tube; because of 

their sensitivity, they were ideal for their intended purpose, but were not entirely suitable for 

personnel dosimetry. On July 1, 1968, a personnel thermoluminescent dosimeter program was 

implemented with the cooperation of the Health Services Laboratory of the Idaho Operations Office. 

The laboratory supplied both lithium-fluoride thermoluminescent dosimeter chips and its experience 

gained at the National Reactor Testing Station. The first routine use of personnel thermoluminescent 

dosimeters at NTS began in 1970 at the NRDS (Boone, 1970). 

 

With the advent of DOE requirements to restrict personnel exposures to “as low as reasonably 

achievable” (ALARA), and with emphasis on accurate dosimetry at low doses, the Environmental 

Sciences Department personnel began evaluating thermoluminescent dosimeter systems and neutron 

dosimeters in the early 1980s as part of an effort to replace the then-current film badge and neutron 

thermoluminescent dosimeters. After evaluating several dosimetry systems, the Panasonic 802 

thermoluminescent dosimeter and the neutron thermoluminescent dosimeter were determined to 

comprise the best combination for NTS exposure conditions. Both were put into use in January 1987 

(ORAUT-TKBS-0008-6, page 85). 

Details regarding the various analyses used and the associated minimum detectable activities are 

presented in ORAUT-TKBS-0008-6. 

6.3 NTS Air Sampling Data 

In 1964, Reynolds Electrical and Engineering Co., Inc. (REECo) established an environmental 

surveillance program at NTS designed to measure radiological conditions throughout the site. The 

purpose of the data collected by the program was not to relate to specific tests, but to relate to general 

site radiation conditions. The short-term objective of the program was to minimize casual personnel 

exposure to radiation by locating and identifying localized radiological environmental conditions. 

The long-range objective of the program was to establish baseline environmental data that could 

provide a reference for comparison with subsequent test activities and radiation measurements (Lewis, 

1965). 
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Since the early 1970s, the environmental surveillance program has routinely monitored atmospheric 

concentrations of tritium, plutonium-238, plutonium-239, and plutonium-240. These were the 

radionuclides identified as most significant to the assessment of potential exposure to workers and 

members of the public. In addition, since the mid-1960s, measurements have been reported for gross 

alpha and gross beta concentrations. 

Tunnel air sampling began in 1957 in locations with the potential for airborne exposure (Arent, 2004). 

Air samplers operated continuously. Radiological Control Technicians checked and exchanged the 

filters each shift. 

Allen (1993) stated that, in general, air monitoring devices were positioned to provide samples 

representative of the worker’s breathing zone. However, some work conditions, such as mining and 

drilling, might have required location of the air monitor intake in the area of highest expected 

concentration “to ensure that airborne radioactivity possibly breathed by the worker is not 

overlooked.” Workplace air monitoring was required in occupied areas that had the potential to 

exceed 10% of any derived air concentration value listed in DOE Order 5480.11 (DOE, 1988). 

The surveillance program grew to include, over time, 12 permanent air-sampling stations in the most 

populated areas of NTS. Initially, the air samplers were low-volume Filter Queen samplers with 8-by10-inch (Gelman Type E) glass-fiber filter papers. Operating times were determined by integrated 

electric timers with flow rates determined by calibrated rotometers. Typical flow rates varied from 3 

to 6 cubic feet per minute; samples were collected weekly. 

In 1971, to achieve lower detection levels, weekly air samples from a given station were batched on a 

monthly basis and subjected to radiochemical analysis for plutonium-239. This new procedure 

included acid dissolution with ion exchange recovery and electroplating onto stainless-steel discs, 

followed by alpha spectroscopy using solid-state surface barrier detectors. Routine analysis for 

plutonium-238 started in 1989 (McArthur, 1989). 

In 1977, a separate sampler was used to collect airborne tritium and tritiated water vapor. The 

sampler was portable and capable of unattended operation for up to two weeks in desert areas 

(Scoggins, 1983). A small electronic pump drew air into the sampler at about 0.5 liter per minute, and 

the tritiated water vapor was removed from the air stream by a silica gel drying column. The dry air 

then passed through a catalytic converter containing platinum to generate tritiated water vapor from 

airborne tritium. Another drying column collected the vapor, in which a small volume of distilled 

water served as a trap for the tritiated water vapor. Appropriate aliquots of condensed moisture were 

obtained by heating the silica gel. Counting via liquid scintillation techniques allowed for the 

determination of the airborne tritium and tritiated water vapor activities. The typical minimum 

detection limit for this analysis was 3 × 10-7 μCi m-3. 

The total number of air sampling stations increased over the years to a peak of 52 in 1989 (Wruble, 

1990). This number remained fairly constant until a gradual reduction began in 1995 (Kinnison, 

1997). This reduction occurred primarily because of a gradual strategy shift from environmental 

monitoring to demonstration of compliance with National Emission Standards for Hazardous Air 

Pollutants approved by the U.S. Environmental Protection Agency (EPA). 
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7.0 Feasibility of Dose Reconstruction for the Proposed Class 

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

governed by both EEOICPA and 42 C.F.R. § 83.13(c)(1). Under that Act and rule, NIOSH must 

establish whether or not it has access to sufficient information either to 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 to members of the class more precisely than a maximum dose estimate. If NIOSH has access to 

sufficient information for either case, NIOSH would then determine that it was feasible to conduct 

dose reconstructions. 

In determining feasibility, NIOSH begins by evaluating whether current or completed NIOSH dose 

reconstructions demonstrate the feasibility of estimating with sufficient accuracy the potential 

radiation exposures of the class (discussed in Section 9.0 of this report). If the conclusion is one of 

infeasibility, NIOSH systematically evaluates the sufficiency of different types of monitoring data, 

process and source or source term data, which together or individually might ensure that NIOSH can 

estimate either the maximum doses that 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 as summarized in Section 7.6. This approach is discussed in OCAS’s SEC Petition Evaluation 

Internal Procedures, available at http://www.cdc.gov/niosh/ocas. The next four major subsections of 

this Evaluation Report examine: 

 The sufficiency and reliability of the available data. (Section 7.1) 

 The feasibility of reconstructing internal radiation doses. (Section 7.2) 

 The feasibility of reconstructing external radiation doses. (Section 7.3) 

 The bases for petition SEC-00084 as submitted by the petitioner. (Section 7.4) 

7.1 Pedigree of NTS Data 

This subsection answers questions that need to be asked before performing a feasibility evaluation. 

Data Pedigree addresses the background, history, and origin of the data. It requires looking at site 

methodologies that may have changed over time; primary versus secondary data sources and whether 

they match; and whether data are internally consistent. All these issues form the bedrock of the 

researcher’s confidence and later conclusions about the data’s quality, credibility, reliability, 

representativeness, and sufficiency for determining the feasibility of dose reconstruction. The 

feasibility evaluation presupposes that data pedigree issues have been settled. 

7.1.1 Internal Data Review 

NIOSH has access to significant documentation describing the internal dosimetry program and 

bioassay methods used at NTS. These records frequently include photocopies of original worksheet 

records, forms, sample transmittal records, and original summary reports generated for distribution to 

DOE and operational organizations within NTS. NIOSH reviewed a statistically valid number of 
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claimant files constituent to the proposed class for internal monitoring data. Consistency and 

credibility of available internal monitoring data were checked by reviewing in vitro and in vivo

analytical results. Thirty-one percent of the NTS records reviewed contained urinalysis data, which 

coincides favorably with the fact that of 1,287 total DOE supplied records for NTS claimants, 32.8 % 

contained some internal dosimetry data. 

As part of the original SEC-00084 Evaluation Report (Rev. 0), NIOSH examined the records supplied 

by DOE for 100 NTS claimants with significant total external whole-body photon exposures 

(cumulative above 1.0 rem). It was NIOSH’s belief at that time that the nature of the potential 

personnel exposure scenarios at NTS was such that significant internal exposures were directly linked 

to (or associated with) significant external exposures. 

The 100 individual files that contained bioassay results included job descriptions for laborers/ bull 

gang workers, miners, tunnel workers, DKY Loco operators, assembly workers, nuclear propulsion 

workers, engineers, as well as other work groups. A summary of the data showing the recorded 

external doses, occupations, and internal data is provided in Table 7-1. 

Table 7-1: Summary of Recorded External and Internal Dose Based on Employment 

Table 7-1 spans 8 pages. 

Total 

External 

Dose 

(rem) 

Job Title 

Internal 

Data 

Availability 

Internal Data Details 

Dates of 

Employment 

(by year) 

36.21 Iron Worker/Foreman Yes 

20 in vitro results, 

most before 1963 (only 0.055 rem 

recorded external dose after 1962) 

1953-1978 

27.729 Radiation Monitor Yes 

100s of in vitro results starting in 

1959 

in vivo, 1975-1994 

1959-1997 

23.19 Radiological Field Operations 

Manager Yes 

100s of in vitro results, 

1957-1959 

in vivo, 1976-1983 

1957-1987 

18.8 Radiation Technician Yes 

2 in vitro results, 1964 

in vivo, 1964 - 1973

1964-1973 

16.784 Laborer Yes 

14 in vitro results, 

1955, 1960, and 1977 

in vivo, 1977 

1952, 1953, 

1954-1956, 

1956-1979 

16.165 

Radiation Services 

Coordinator/Radiation Field 

Ops Branch Chief 

Yes 

About 250 in vitro results, 

1971-1991 

in vivo, 1976-1992 

1960-1993 

15.725 Radiation Safety Supervisor Yes 52 in vitro results, 

1957-1963 1957-1966 

15.085 Shifter/Miner Yes 97 in vitro results, 

1960-1968 1961-1969 
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Table 7-1: Summary of Recorded External and Internal Dose Based on Employment 

Table 7-1 spans 8 pages. 

Total 

External 

Dose 

(rem) 

Job Title 

Internal 

Data 

Availability 

Internal Data Details 

Dates of 

Employment 

(by year) 

14.594 Health Physicist Yes 

About 250 in vitro results, 

1963 and 1965-1990 

in vivo, 1980, 1983, 1986, and 

1989-1991 

1962-1963, 

1978-2005 

14.475 Miner/Oiler/Operator Yes 

More than 100 in vitro results, 

1960-1986 

in vivo, 1984, 1986 

1957-1987 

(with breaks) 

13.79 Messenger Clerk Monitor Yes 

Over 500 in vitro results, 

1961-1990 

in vivo, 1977-1990 

1957-1991 

13.125 Monitor/Radiation Safety 

Expert Yes 

584 in vitro results, 

1957-1994 

in vivo, 1976-1993 

1956-1995 

12.265 Tunnel Walker Yes 

Over 75 in vitro results, 

1962-1966 

thyroid count, 1966 

1961-1968 

12.155 Radiation Monitor Yes 

Approximately 400 in vitro results, 

1956-1982 

in vivo, 1969, 1975-1981 

1961-1982 

11.751 Environmental Safety and 

Health Yes (breaks) 

Over 300 in vitro results, 

1964-1993 

in vivo, 1975-1983 

1964-2000 

10.42 Shifter/Miner Yes 

16 in vitro results, 

1959, 1961, 1966, and 1977 

in vivo, 1977-1987 

1958-1987 

(with breaks) 

9.742 Radiation Safety/Technical Yes 

Over 100 in vitro results, 

1968-1996 

in vivo 1975-1995 

1967-2007 

8.985 Miner Yes More than 100 in vitro results, 

1960-1963 1958-1971 

8.753 Machine Tool Operator/ 

Laborer Yes 

Approximately 60 in vitro results, 

all prior to 1960 (all recorded 

external dose received before 

1963) 

1951-1977 

(with breaks) 

8.375 Tunnel Walker Yes 

Approximately 150 in vitro results, 

1961-1977 

in vivo, 1977-1987 

1958-1987 
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Table 7-1: Summary of Recorded External and Internal Dose Based on Employment 

Table 7-1 spans 8 pages. 

Total 

External 

Dose 

(rem) 

Job Title 

Internal 

Data 

Availability 

Internal Data Details 

Dates of 

Employment 

(by year) 

8.015 Labor Foreman Yes 

Approximately 60 in vitro results 

(all before 1960 when external 

dose was also recorded) 

1956-1971 

(with breaks) 

7.99 Radiation Monitor Yes 

Approximately 175 in vitro results, 

1965-1976 

in vivo, 1975 and 1976 

1965-1976 

7.415 Chemical Technician at NRDS Yes 

in vivo results, 

1965, 1969, 1 positive cesium 

result in 1965 

1964-1969 

7.324 Foreman of the Sanitation 

Department Yes 

Over 40 in vitro results, 

(all recorded external dose was 

prior to 1960) 

in vivo, 1982, 1983, and 1984 

1953, 1957, 

1961-1984 

7.32 Laborer/Miner Yes 

Approximately 40 in vitro results, 

all prior to 1960 (external exposure 

received before 1963) 

1952-1987 

7.195 Shifter/Miner/Tunnel Walker Yes 7 in vitro results, 

1959 and 1972 

1958-1986 

(with breaks) 

6.98 Mucking Operator Yes 37 in vitro results, 

1962, 1965, and 1967 

1961-1977 

(with breaks) 

6.725 Laborer Yes Bioassay data prior to 1963 

(external exposure prior to 1963) 1952-1965 

6.58 Monitor Yes 67 in vitro results, 

1964-1970 1964-1971 

6.475 Monitor, Radiac Repairman Yes Plutonium bioassay, 1963 1962-1967 

6.285 Shaft Miner/Miner Yes 

10 in vitro results, 

all prior to 1960 (all recorded 

external dose received before 

1963) 

1961-1971 

(with breaks) 

5.915 Miner Yes 1 in vitro result, 1969 1961-1971 

(with break) 

5.9 Hoist/Universal Operator Yes 

Over 400 in vitro results, 

most before 1963 (only 0.065 rem 

external after 1962) 

1958-1970 

5.835 Bull Gang/Laborer Yes 17 in vitro results, 

1957 and 1966 

1958-1967 

(with breaks) 

5.67 Machine Operator Yes 

Over 40 in vitro results, 1962 

 

1 in vitro result, 1963 (only 0.245 

rem external after 1962) 

1959-1971 
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Table 7-1: Summary of Recorded External and Internal Dose Based on Employment 

Table 7-1 spans 8 pages. 

Total 

External 

Dose 

(rem) 

Job Title 

Internal 

Data 

Availability 

Internal Data Details 

Dates of 

Employment 

(by year) 

5.54 Shifter/Miner/Tunnel Walker Yes About 170 in vitro results, 

1961-1964 

1958-1975 

 (with breaks) 

5.51 Radiation Monitor/Manager Yes 44 in vitro results, 

1963-1972 1963-1977 

5.43 Nuclear Engineer (NRDS) Yes 1 in vitro, 1965 1963-1973 

5.245 Nuclear Engineer Yes 

About 175 in vitro results, 

1968-1973 and 1975 

in vivo, 1978-1987 

1963-1987 

5.18 Wireman Yes 

10 in vitro results, 

1962 and 1963 (no recorded 

external dose after 1963) 

1962-1994 

5.155 Miner/Tunnel Worker - Smoot Yes 

Approximately 80 in vitro results, 

1962 and 1963 (no recorded 

external dose after 1963) 

1961-1964 

5.11 Scientist/Industrial Hygienist Yes 

100s of in vitro results, 

1966-1994 

in vivo, 1975-1994 

1966-1999 

4.835 Instrument Mechanic Yes 

4 in vitro results, 

1973 and 1977, 

in vivo, 1977

1955-1987 

4.825 Heavy Equipment Operator - 

Tunnels Yes 

50 in vitro results,

1963-1978 

in vivo, 1977, 1978, and 1979

1961-1984 

(with breaks) 

4.765 Diamond Core Driller Yes 12 in vitro results, 

1961, 1962, and 1963 1961-1964 

4.753 Monitor Yes 

Over 700 in vitro results, 

1968-2005 

In vivo, 1969-1991 

1962-1994 

4.745 Laborer/Bull Gang Yes 

About 100 in vitro results,

1957-1990, none other than tritium 

in vivo, 1979, 1980, 1982, 1984, 

1986, 1988, and 1990

1957, 1961-

1962, 

1964-1992 

4.735 DKY Loco Operator/Miner Yes 30 in vitro results, 

1962, 1972-1977 

1958-1978 

(with breaks) 

4.669 Engineer Yes 

29 in vitro results, 

1963 and 1977 

in vivo, 1976, 1980, 1981

1961-1983 
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Table 7-1: Summary of Recorded External and Internal Dose Based on Employment 

Table 7-1 spans 8 pages. 

Total 

External 

Dose 

(rem) 

Job Title 

Internal 

Data 

Availability 

Internal Data Details 

Dates of 

Employment 

(by year) 

4.58 Miner/Tunnel Supervisor Yes 

35 in vitro results,

1962, 1966, 1967, and 1977-1980 

in vivo, 1977, 1984, 1986, and 

1987

1962-1987 

4.565 Miner/Tunnel Walker Yes Approximately 15 in vitro results, 

1962 and 1966 1961-1967 

4.485 Laborer Yes 1 in vitro result, 1969 1962-1985 

4.468 Shifter/Miner Yes 

Approximately 250 in vitro results, 

1963-1990 

in vivo, 1977-1990 

1962, 1963, 

1969-1991 

4.305 Miner Yes 5 in vitro, 1961 

(no recorded external after 1962) 1961, 1964 

4.26 Laborer Yes 3 in vitro results, 1965 

1957, 

1962-1971, 

1971-1973, 

1973-1992 

4.255 Radiographer Yes About 65 in vitro results, 

1970-1972 1958-1979 

4.2 Laborer/Operator Yes 

1 in vitro result, 

1957 (external dose recorded 

before 1963) 

1954-1968 

(with breaks) 

4.18 Miner Yes 24 in vitro results, 

1966 and 1967 1964-1968 

4.085 Ops and Rig Superintendent Yes 

Approximately 250 in vitro results, 

1965-1986 

in vivo, 1977-1994 

1961-1995 

3.9 Nuclear Technician Yes 3 in vivo results, 1966 1963-1967 

3.363 Radiation Instrument 

Technician Yes 

Approximately 300 in vitro results, 

1966-1992 

in vivo, 1977-1991 

1965-1992 

3.075 Laborer Yes 6 in vitro results, 1963 1960, 1961-1982 

2.955 Miner/Derrickman Yes 

7 in vitro results, 1963 

thyroid count, 1965 

1961-1965 

(with breaks) 

2.85 Driller Yes 

Approximately 70 in vitro results, 

many thyroid counts 

thyroid counts, 1976-1991 

1962-1991 
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Table 7-1: Summary of Recorded External and Internal Dose Based on Employment 

Table 7-1 spans 8 pages. 

Total 

External 

Dose 

(rem) 

Job Title 

Internal 

Data 

Availability 

Internal Data Details 

Dates of 

Employment 

(by year) 

2.835 Laborer/Carpenter Yes 

in vitro results, 

1959 and 1962 

in vivo, 1979, 1984, 1987, and 

1988

1958-1988 

2.775 Drill Foreman/Derrickman Yes Approximately 100 in vitro results, 

1962, 1965-1968 1961-1973 

2.765 Miner/Supervisor Yes 

Approximately 30 in vitro results, 

1962, 1963 (no recorded external 

dose after 1963) 

1958-1983 

2.73 Driller Foreman/Operator Yes 

Approximately 15 in vitro results, 

1962-1973 

in vivo, 1977-1989 

1962-1989 

2.64 Driller/Unknown Yes 1 in vitro result, 1962 1957-1980 

(with breaks) 

2.58 Heavy Duty 

Repairman/Welder Yes 1 in vitro result, 1970 1958-1974 (with breaks) 

2.44 Security Yes 

196 in vitro results, 

1981-1992 

in vivo, 1978, 1981, and 1989 

1957-1993 

2.41 Radiation Monitor Yes 

Over 100 in vitro results, 

1963-1977 

In vivo, 1975 and 1977 

1963-1977 

2.245 Machining at NRDS Yes in vivo results, 

1967, and 1968, positive results 1965-1968 

2.225 Bull Gang/Laborer Yes 2 in vitro results, 

1961and 1965 

1961-1986 

(with breaks) 

2.225 Bull Gang/Laborer Yes 8 in vitro results, 1970 1965-1994 

(with breaks) 

2.225 Mechanic/Pipefitter Yes 12 in vitro results, 

1964, 1965, and 1973 1963-1973 

2.135 Wireman (tunnels) Yes 

49 in vitro results, 

1962 (most of recorded external 

exposure occurred in 1962) 

1961-1983 

2.13 Radiation Safety/Scientist Yes 1 in vitro result, 1966 1957-2001 

(with one break) 

2.105 Radiation Monitor Yes 

Approximately 190 in vitro results, 

1966-1975 

in vivo, 1975 

1965-1976 

2.095 Oiler, Driller, Universal 

Operator Yes 16 in vitro results, 1962 1961-1966 

2.075 Miner Yes 11 in vitro results, 1962 1961-1969 
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Table 7-1: Summary of Recorded External and Internal Dose Based on Employment 

Table 7-1 spans 8 pages. 

Total 

External 

Dose 

(rem) 

Job Title 

Internal 

Data 

Availability 

Internal Data Details 

Dates of 

Employment 

(by year) 

2.028 Miner Yes Approximately 40 in vitro results, 

1963-1972 

1965-1975 

(with breaks) 

1.95 Electrician Yes 

2 in vitro results, 1964 

1 in vivo result, 1969 

1963-1969 

1.945 Miner/DYO Loco Operator Yes 100s of in vitro results and in vivo

data 

1964-1984 

(with breaks) 

1.85 Miner/Driller Yes 

16 in vitro results, 

1965, 1970, and 1989 

in vivo, 1988-1992 

1965-1993 

(with breaks) 

1.715 Driller/Miner Yes 

116 in vitro results, 

1966, 1972, 1974, 1975, 1977-

1982, 1986, and 1989-1990 

in vivo, 1976-1983 

1964-1990 

(with breaks) 

1.695 Miner Yes 

6 in vitro results, 

1967, 1968, and 1970, some 

positive 

1961-1971 

1.655 Chemist Yes 

5 in vitro, 1965 

in vivo, 1965 

1963-1968 

1.625 Miner/Bull Gang Operator Yes 

221 in vitro results, 

1970-1987 

in vivo, 1977-1986 

1967-1987 

1.52 Operator/Dinky Loco 

Operator Yes 

1 in vitro result, 1959 

(.105 mrem recorded external 

exposure after 1960) 

1957-1967 

(with breaks) 

1.44 First Aid Man/Monitor Yes 27 in vitro results, 

1970-1973 

1963-1970 

(with breaks) 

1.435 Laborer/Iron Worker Yes 2 in vitro results, 1966 1962-1969 

(with breaks) 

1.3 Assembly of Reactors Yes 1 in vitro result, 1963 1962-1971 

(with breaks) 

1.3 Miner/Laborer Yes 2 in vitro results, 1965 1964-1975 

(with breaks) 

1.275 Miner/Tunnel Walker Yes 

67 in vitro results, 

1972-1990 

in vivo, 1977-1993 

1968-present 

(with breaks) 

1.25 Dozer Operator/Foreman Yes 1 in vitro result, 1966 1955-1975 

1.225 Miner/Laborer Yes 4 in vitro results, 1966 1964-1967 

(with breaks) 
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Table 7-1: Summary of Recorded External and Internal Dose Based on Employment 

Table 7-1 spans 8 pages. 

Total 

External 

Dose 

(rem) 

Job Title 

Internal 

Data 

Availability 

Internal Data Details 

Dates of 

Employment 

(by year) 

1.155 DKY Loco Operator/Miner Yes 

19 in vitro results, 

1970-1981 

in vivo, 1979-1990 

1969-1990 

(with breaks) 

1.1 DKY Loco Operator Yes 55 in vitro results, 1966 1965-1969 

(with breaks) 

1.025 Shifter/Miner/Tunnel Walker Yes 

12 in vitro results, 

1970 and 1973 

1964-1975 

(with breaks) 

Source: NOCTS 

From these reviews of claimant data supplied by DOE, NIOSH has found thousands of available 

bioassay results. 

In addition to the above data, NIOSH has obtained the complete set of electronic bioassay records 

from NTS (NTS Bioassay Data, 2009). As depicted in Figure 6-1, urinalysis data were found for 

tritium, beta, gamma, and plutonium. A complete pedigree analysis of this newly-received electronic 

data has not been performed by NIOSH. However, because these data provide information of 

significance for the class under evaluation, they have been included in NIOSH’s internal assessment 

provided in Section 7.2 of this revised evaluation report. 

7.1.2 External Data Review 

NIOSH has access to extensive documentation describing the NTS external dosimetry program, 

including the procedures and controls used to ensure universal monitoring and accuracy in the 

recordkeeping. Based on the review of the data available, credible and consistent external dosimetry 

records representative of members of the proposed class are available for dose reconstruction. 

As early as 1957, with the decision to progress to universal external monitoring, NTS recognized the 

potential problems associated with operating a Personnel Radiation Dosimetry program in which large 

numbers of film badges would be processed for recording radiation dose. Consideration of accounting 

problems associated with the program, as well as the methods NTS chose to address these issues are 

documented in the report titled, Electronic Data Processing as Applied to Personnel Radiation 

Dosimetry (Wilcox, 1958). NTS chose to address the majority of the identified concerns through 

automation processes. In 1957, daily reports were prepared and distributed each morning to 

approximately 70 organization representatives. Weekly summary dosage reports listing accrued 

quarterly and annual gamma radiation dosage for all measured personnel were prepared and 

distributed (Wilcox, 1958; NTS, 1968). These reports are available to NIOSH. 
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Film packet control was achieved through the use of an Addressograph plate. The plate was used for 

employee identification and was included in the film packet holder. The plate was stamped with the 

employee’s name, NTS number, and the number code, which identified the employing organization. 

When the film packet was exchanged, the plate was used in conjunction with a stamping machine to 

print the above information on the IBM film packet issue card (NTS, 1968). NTS was very concerned 

with personnel dosimetry accuracy and implemented rigorous quality assurance controls regarding 

dosimeter calibration, issuance, and tracking; this concern is documented in detailed procedures (NTS, 

no date; NTS, 1968; REECo, 1991; NTS, 1978; Wilcox, 1961) and throughout NTS memos and 

information bulletins. Further, interviews confirmed the prevailing concern with accuracy in the 

dosimetry records. A personal contact with a REECo Health Physics Manager and member of the 

Radiation Protection organization at NTS since the mid 1960s is quoted below (Smith, 2007): 

Dose determined from the dosimetry systems (film and TLD) were handled in accordance 

with the "QA" procedure in place at the time the doses were determined. Systems were 

calibrated daily and performance checked with each batch. In the film era, results were 

keypunched by two different individuals to verify that the results going into the personnel 

record system were correct. During the TLD era, the reader parameters were checked 

daily; the computer system's algorithm calculated doses automatically that were sent directly 

to a disk that upon laboratory verification was sent to the personnel dosimetry records 

system. These computer parameters were also saved with the raw data. Additionally, as each 

monthly Dosimetry Report was generated for distribution to organizations, it was again 

visually checked by the Dosimetry Supervisor. Once their monthly reports were verified, the 

reports were retained in the database and held for the annual reports and the creation of the 

then AEC/DOE 190 and 191 reports that were sent to Headquarters. 

During the time film badges were in use, personnel radiation exposure records were maintained on 

cards which contained information available for electronic data processing machines. When a film 

badge was received for processing, the identically numbered IBM card was pulled and the film badge 

density, processing batch number, and date of processing was recorded on it. After all the film for a 

particular processing batch was measured for net optical density and the information recorded on the 

card, two batch density totals were recorded on adding machine tapes by different individuals. One 

tape was filed at the Processing Laboratory and the other was transmitted with the information cards 

to the Machine Accounting Facility. Employees had a dosage “master card” filed numerically by 

identification number. When the information cards with information for a particular dosimeter 

exchange arrived at the Machine Accounting Facility, the accumulated personnel gamma radiation 

exposure was recorded on the master card. Photocopies of the issue cards, summary reports, and other 

original source information is frequently included as part of the EEOICPA claimant files. 

7.2 Internal Radiation Doses at NTS 

Emphasis at NTS was placed on monitoring sources of external exposures rather than internal 

exposures, particularly during atmospheric testing. This emphasis was based on animal data 

comparing inhalation dose to external dose. The principal source of internal radiation dose for 

members of the proposed class was from the intake of radionuclides released during venting of 

belowground weapons testing and from intakes during tunnel re-entry and operations. Other sources 

include intake of resuspended residual contamination from the above-ground testing period prior to 

1962 and from safety testing. Initially at NTS, screening for internal intakes was performed using 
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nasal swabs, respirator swipes, and urine samples when surface or air contamination was found or 

suspected. A positive nasal swab initiated the collection of a urine sample. 

The NTS contractor, REECo, implemented bioassay in 1958 when workers involved in incidents were 

sampled via nasal swab. By 1961, NTS was conducting routine bioassay for tritium, plutonium-239, 

gross fission products, and gamma emitters. Early bioassay efforts were conducted after weapons 

testing and drillbacks. The routine bioassay program was conducted at NTS to verify that workers 

were not routinely exposed to airborne radioactive materials. REECo used in vitro methods until 

1967 when whole-body counting was introduced at NTS. Routine in vivo counting was implemented 

at NTS in 1975. 

As demonstrated by the data presented in Table 7-1, by 1961, Radiation Safety department staff 

involved with underground work, were also involved in a routine bioassay monitoring program 

(REECo, 1961). Other workers and/or worker groups that were on a routine bioassay monitoring 

program (also identified in Table 7-1) included miners, workers involved in re-entry events, and 

workers in areas where levels of airborne radioactivity exceeded NTS guidelines (University of 

California, 1965; Reeves, 1962; REECo, 1961; REECo, date unknown; LRL, 1961). Other types of 

bioassay monitoring at NTS included special sampling (designated, job specific bioassay monitoring) 

and incident sampling. 

Per discussions with former NTS workers, respiratory protection was used beginning in the early 

years of site operations. In addition, Radiation Safety Monitors performed fit checks of respirators in 

the field using smoke tests (Marsh, 1983). By 1962, the use of respiratory protection was part of the 

NTS procedures for controlling internal exposures to radioactive materials (Reeves, 1962). The NTS 

respiratory protection program was based on the American Industrial Hygiene Association (AIHA, 

1963), U.S. Atomic Energy Commission (Morgan, 1953; Biles, 1973), and International Atomic 

Energy Agency (IAEA, 1967) principles current at the time. 

Protocols for bioassay monitoring remained fairly constant until 1993 when the DOE Radiological 

Control Manual (DOE, 1992) was implemented. With the implementation of the Radiation Control 

Manual, as documented by Allen, 1993, workers classified as Radiation Workers II were routinely 

monitored for internal intakes of radioactivity by bioassay. These monitored workers were those 

determined most likely to receive intakes of radioactive material resulting in a committed effective 

dose equivalent (CEDE) of 100 mrem or more. At any one time, approximately 300 workers were 

monitored via bioassay. While the total work force numbered as high as 12,000 workers, most 

workers were classified as non-radiation workers under the DOE Radiological Control Manual. 

Information available in 2003 indicated that 21 workers had been assessed with annual internal doses 

of 100 mrem CEDE or more since the start of 1994 (McMahon, 2003). Eleven of those 21 workers 

received their dose from one project (E Tunnel Project) during 1994. The highest dose calculated for 

one of these intakes was 1,337 mrem CEDE (French, 1995). Since 1995, the frequency of annual 

internal doses of 100 mrem or more was approximately 1 in 100 monitored workers. Projects that 

involved working with plutonium and americium contamination were the only projects that resulted in 

intakes of 100 mrem or more since 1994. The low frequencies of intakes amounting to 100 mrem 

CEDE or more in a year to an individual is validation of the post-1992 NTS radiological control 

efforts to minimize worker intakes (McMahon, 2003). 
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Routine bioassays at NTS are documented in ORAUT-TKBS-0008-5 Attachment 5D.4.1. Nonroutine bioassay types included job-specific monitoring and occurrence response. Whole-body 

counts, lung counts, thyroid counts, and biological sampling were performed as soon as practicable 

after a suspected intake (Allen, 1993). Special, or one-time, bioassay samples were sometimes 

collected from workers after tasks with limited duration, but high potential for exposure. The special 

bioassay program was also administered to assess the internal dose delivered by inadvertent and 

unexpected intakes of radioactive materials (Allen, 1993; McMahon, 2003). By 2000, routine 

monitoring resembled special bioassay monitoring in that most projects were short term; monitored 

workers were provided baseline and post-work sampling (McMahon, 2003). 

The routine bioassay program at NTS included the collection of urine samples (from workers involved 

in the drillbacks) after each drillback operation. NIOSH does have data (claimant data, supplied by 

DOE) sufficient to demonstrate that drillback workers routinely provided bioassay samples. Drillback 

personnel were primarily exposed to gaseous and particulate fission and activation products. Starting 

in 1963, engineering devices were used to prevent the escape of radioactive gases and particulates; 

however, there were still occasional unintended releases (Kimmel, 1963; REECo, 1964). 

With the exception of work performed in seepage areas, operations conducted within tunnels are 

considered to have been performed in dry conditions. The pathways for personnel exposure included 

loss of containment during drilling or coring and re-suspension of particulate fission or activation 

products during the coring operations. Radionuclides that would have resulted from loss of 

containment and were of primary concern for internal dose were iodine-131, iodine-133, and cesium137. Radionuclides of significant concern to internal dose that would have resulted from resuspension are listed in Table 7-2. 

Table 7-2: Drillback Re-suspension, Reentry/Mineback Re-suspension, Radionuclides of Concern for Dose V. 

Time After Test 

1 day 10 days 100 days 365 days 10,000 days 

Zirconium-95 Strontium-89 Strontium-89 Strontium-90 Strontium-90 

Zirconium-97 Yttrium-91 Strontium-90 Zirconium-95 Cesium-137 

Molybdenum-99 Zirconium-95 Yttrium-91 Ruthenium-106 

Ruthenium-106 Ruthenium-103 Zirconium-95 Cerium-139 

Iodine-131 Ruthenium-106 Ruthenium-103 Cerium-144 

Tellurium-132 Iodine-131 Ruthenium-106 Promethium-147 

Iodine-133 Tellurium-132 Cerium-144 

Iodine-135 Cerium-141 

Cerium-143 Cerium-144 

Cerium-144 

The routine bioassay protocol for drillback workers was to collect quarterly urine samples after each 

drillback operation. Urine samples obtained from drillback workers were analyzed by gross beta 

counting. If the beta result indicated potential radiation exposure, a separate aliquot from the same 

sample was analyzed for gross gamma-counting, using liquid scintillation (Dummer, 1958). In 1961, 

NTS analyzed urine samples for gross fission products before performing radionuclide-specific 

analyses (Geiger, 1961). Radionuclide-specific analysis performed at NTS included cesium-137, 
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strontium-89/90, barium, lanthanide rare earths, and less frequently, other fission products that were 

co-precipitated with alkaline earth phosphate. If significant quantities of radioactive material were not 

detected, no additional analyses were performed. 

Urine samples were analyzed by gamma spectroscopy for gross radioactivity and isotope 

identification. When specific radionuclides were not identified, gross fission product results were 

attributed to the radionuclides shown in Table 7-2, taking into consideration the amount of time 

between potential exposure and the device test. 

Whole-body counting was performed for some of the drillback workers either annually or after 

situations where intakes were considered plausible. These drillback workers included the following 

specific drilling job categories: radiation monitor, driller operator supervisor, driller operator, rotary 

drill operator/rotary drill helper, driller helper, derrickman, motorman, fishing tool engineer, and drill 

helper trainee. 

Reentry and mineback operations were similar, in terms of intake potential, to those of drillback 

operations. There were four pathways for exposure during reentry and mineback operations. The first 

pathway was based on a loss of containment in the drilling or coring operations during routine 

drilling, or due to containment equipment failure. The radionuclides of concern included gaseous 

fission and activation products or their particulate daughters. The second pathway was re-suspension 

of particulate fission or activation products during the coring operations of the mineback. The third 

exposure pathway was gaseous fission or activation products seeping through fissures in the rock and 

reentering the working areas of the tunnel. The final intake pathway existed when the line-of-sight 

pipe was opened to remove experiment equipment and samples (ORAUT-TKBS-0008-5, page 57-58). 

Radionuclides of dosimetric concern from containment loss included tritium, iodine-131, iodine-133, 

and cesium-137. Additional radionuclides of dosimetric concern from re-suspension are listed in 

Table 7-2. Radionuclides of dosimetric concern from fissures and line-of-sight pipe openings 

included tritium, cobalt-60, antimony-124, iodine-131, iodine-133, and cesium-137. The trigger for 

urine sample bioassay of reentry and mineback workers was air sample results. Tunnel air sampling 

began in 1957 in locations with the potential for airborne exposure (ORAUT-TKBS-0008-5, page 58). 

Air samplers operated continuously. Radiation control technicians exchanged and counted the filters 

each shift. Bioassay was performed only when there was an indication of an effluent release 

(ORAUT-TKBS-0008-5, page 58). Urine samples collected from these workers were analyzed for 

gamma activity and tritium. Annual whole-body counts were conducted on a routine basis for specific 

radiation workers and on a special basis following any situation for which intake was considered 

likely (once in vivo monitoring began). Specific tunnel job categories included Miner, Bull Gang 

(Underground Laborer), Mucker (Muck Machine Operator), Shifter, Tunnel Walker, and Dinky 

Locomotive Operator. Specific to other tunnel operations, tritium was the radionuclide of dosimetric 

concern. When bioassay was collected from these workers, they were analyzed for tritium. Tunnel 

workers also had the potential to be occupationally exposed to radon and thoron daughters (ORAUTTKBS-0008-5, page 17). 

At the Decontamination Facility, radionuclides of dose concern are the same as those listed in Table 

7-3. Workers in this facility were sampled by urinalysis on a quarterly basis and were also provided 

with annual whole-body counts. Urine samples were gamma-counted and analyzed for gross fission 

products, plutonium-238, plutonium-239, plutonium-240, and americium-241. 
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The Test Treatability Facility was a pilot project to bench-test technologies that would be used to 

decontaminate soil containing transuranic materials. The concentrations of radionuclides in the soils 

were not intended to exceed a few picocuries per gram of soil. Radionuclides of dose concern were 

plutonium-238, plutonium-239, plutonium-240, and americium-241. Workers in this facility were 

sampled by urinalysis on a quarterly basis and received annual whole-body counts. Urine samples 

were counted on a gamma analyzer for isotopic identification and were analyzed for plutonium and 

americium (ORAUT-TKBS-0008-5, page 58). 

Similarly, the radionuclides of dose concern at the Atmospheric Weapon Safety Tests Areas included 

plutonium-238, plutonium-239, plutonium-240, and americium-241. Workers in this facility were 

sampled by urinalysis on a quarterly basis and received annual whole-body counts. Urine samples 

were counted on a gamma analyzer for isotopic identification and were analyzed for plutonium and 

americium (ORAUT-TKBS-0008-5, page 58-59). 

Table 7-3 lists the radionuclides of dose concern for the Atmospheric Weapons Test Areas. Workers 

in the routine bioassay program provided urinalysis samples on a quarterly basis and received wholebody counts annually. Some area monitoring personnel received periodic lung counts. Urine samples 

were analyzed for gamma-emitting radionuclides, gross fission products, plutonium, and americium 

(ORAUT-TKBS-0008-5). 

Table 7-3: Radionuclides of Concern in Atmospheric Weapons Test Areas 

Cobalt-60 Antimony-125 Cesium-137 Europium-155 Plutonium-239

Strontium-90 Barium-133 Europium-152 Lutetium-174 Plutonium-240

Ruthenium-101 Cesium-134 Europium-154 Plutonium-238 Americium-241

Ruthenium -102m 

Source: ORAUT-TKBS-0008-5. 

Radionuclides of dosimetric concern for workers at the Low-Level Waste Facility in Area 3 are listed 

in Table 7-4. Workers in this facility were sampled by urinalysis on a quarterly basis and received 

annual whole-body counts. Urine samples were analyzed for gross fission products, plutonium, and 

americium. Table 7-5 lists radionuclides of dosimetric concern for the low-level waste site located in 

Area 5. Area 5 Radioactive Waste Management shallow-land burial workers were sampled by 

urinalysis on a quarterly basis and were provided annual whole-body counts. Urine samples were 

analyzed for gamma-emitters, tritium, gross fission products, plutonium, and americium (ORAUTTKBS-0008-5). 
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Table 7-4: Radionuclides of Concern in Crater Disposal-Area 3 RWMS 

Manganese-54 Ruthenium-103 Cerium-144 Uranium-233 Plutonium-240

Cobalt-60 Ruthenium-106 Actinium-227 Uranium-234 Plutonium-241

Strontium -85 Cesium-134 Thorium-228 Uranium-238 Plutonium-242

Strontium -90 Cesium-137 Thorium-230 Plutonium-238 Americium-241

Zirconium-95 Barium-140 Thorium-232 Plutonium-239 Americium-243

Niobium-95 Cerium-141

Source: ORAUT-TKBS-0008-5. 

Table 7-5: Radionuclides of Concern in Shallow Land Burial-Area 5 

Hydrogen-3 Molybdenum-99 Cerium-141 Actinium-227 Uranium-238

Sodium-22 Ruthenium-103 Cerium-144 Thorium-228 Plutonium-238

Manganese-54 Ruthenium-106 Europium-152 Thorium-230 Plutonium-239

Cobalt-57 Antimony-124 Europium-154 Thorium-232 Plutonium-240

Cobalt-60 Antimony-125 Europium-155 Uranium-233 Plutonium-241

Strontium-85 Barium-133 Ytterbium-169 Uranium-234 Americium-241

Strontium-90 Cesium-134 Tantalum-182 Uranium-235 Plutonium-242

Zirconium-95 Cesium-137 Iridium-192 Neptunium-237 Americium-243

Niobium-95 Barium-140 Radium-226 

Source: ORAUT-TKBS-0008-5. 

Tests of nuclear reactors for use as propulsion units were conducted above the ground at Area 25. 

Fission and activation products arising from these tests were dispersed into the environment. The 

radionuclides of dosimetric concern included tritium, cobalt-60, strontium-90, cesium-137, and 

europium-152. Workers involved with propulsion tests were sampled by urinalysis on a quarterly 

basis and received annual whole-body counts. Urine samples were analyzed for gamma-emitters, 

tritium, gross fission products, plutonium, and americium (ORAUT-TKBS-0008-5, page 61). 

Workers assigned to radiography operations (including well-logging) were potentially exposed to 

sealed iridium-192, cobalt-60, iodine-131, cesium-137, radium-226, thorium-228, plutonium-238, and 

plutonium-241 sources. Bioassay was performed for these workers only if a loss of source 

containment was detected. Urine samples were gamma-counted (ORAUT-TKBS-0008-5, page 60). 
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For technicians and other workers assigned to Radiation Instrument Calibration Facilities, 

radionuclides of dosimetric concern are listed in Table 7-6. Routine bioassay, including quarterly 

urine samples and annual whole-body counts, were performed for personnel who regularly worked 

with calibration sources. Urine samples were analyzed for tritium and plutonium. A special bioassay 

whole-body count and/or urine sample collection was performed if the loss of calibration source 

containment was detected. 

Table 7-6: Radionuclides of Concern in Radiation Instrument Calibration Facilities 

Hydrogen-3 Strontium-90 Radium-226 Thorium-230 Plutonium-239

Cobalt-60 Cesium-137 Thorium-228 Plutonium-238 Americium-241 

Source: ORAUT-TKBS-0008-5. 

NTS performed several radiochemistry and analytical procedures in addition to analyzing bioassay 

samples. Radionuclides of dosimetric concern to laboratory staff are listed in Table 7-7. Only 

personnel routinely handling uncontained radioactive materials were provided urinalysis or wholebody counting. Urine samples were gamma-counted and analyzed for tritium, gross fission products, 

and plutonium (ORAUT-TKBS-0008-5). 

Table 7-7: Radionuclides of Concern in Radiochemistry and Counting Laboratories 

Hydrogen-3 Strontium-85 Cadmium-109 Cerium-144 Americium-241 

Sodium-24 Yttrium-88 Tin-113 Europium-152 Plutonium-242 

Cobalt-57 Strontium-90 Cesium-137 Mercury-20 Americium-243 

Cobalt-60 Yttrium-90 Cerium-139 plutonium-239 Curium-244 

Source: ORAUT-TKBS-0008-5. 

Workers involved with device assembly in Area 27 had the potential for exposure to tritium, uranium235, plutonium-239, and plutonium-240. NIOSH interviewed 14 former workers or their survivors, 

none of which reported involvement with device assembly. It is plausible that some NTS employees 

could have worked in device assembly, but based on the documentation NIOSH has reviewed, NIOSH 

is confident that very few NTS workers were associated directly with device assembly. 
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NTS used respiratory protection to limit inhalation of radionuclides when air sampling data exceeded 

the values listed in Table 7-8. The use of respiratory protection was included as part of the procedures 

for re-entry work (LRL, 1961; University of California, 1965). 

Table 7-8: Respiratory Protection Action Levels 

Year Respiratory Protection 

No respirator < 9.6 x 103 dpm/m3 hrs (alpha) per quarter year 

No respirator (short periods) < 100 dpm/m3 (alpha) 

Respirator required > 100 dpm/m3 (alpha) 

No respirator < 2.2 x 104 dpm/m3 (beta + gamma) 

Respirator required > 2.2 x 104 dpm/m3 (beta + gamma) 

1957 

Note: Respirators using filters have an efficiency up to 99.9% for particles as small as 0.3 micron in diameter 

Ultra-filter respirator can be worn to levels < 500 dpm/m3 (plutonium-239 alpha) 

Full-face mask with dust, fume, and mist canister required in levels from 500 to 10,000 dpm/m3 (plutonium-239 

alpha) 1959 

Air-supplied mask recommended when levels > 10,000 dpm/m3

 (plutonium-239 alpha) 

0 to 100 dpm/m3 (alpha)—no respiratory protection for short-term exposure 

4 x 10-11 μCi/cc (beta, gamma)—respiratory protection required 

100 to 100,000 dpm/m3 (alpha)—high-filtration, full-face respirator (99.9% effective) 1968 

Greater than the above levels—self-contained breathing apparatus 

Source: ORAUT-TKBS-0008-5. 

In summary, the primary elements of internal dosimetric concern at NTS include plutonium 

(plutonium-238, plutonium-239, plutonium-240, plutonium-241, plutonium-242), uranium (uranium233, uranium-234, uranium-235, uranium-236, uranium-238) , americium (americium-241, 

americium-243), curium (curium-244), strontium (strontium-85, strontium-89, strontium/ yttrium-90), 

cesium (cesium-137), and tritium (H-3). Iodine was of concern following full criticality experiments 

(i.e., atmospheric testing and venting). Inhalation would have been the most significant mode of 

intake, so the lungs are organs of concern in all cases. Cesium and tritium irradiate the whole body 

relatively uniformly and do not concentrate in any one organ or type of tissue preferentially (ORAUTTKBS-0008-5). 

7.2.1 Bioassay Protocols Performed at NTS 

The following subsections summarize monitoring performed at NTS and the extent and limitations of 

information available for reconstructing occupational internal doses potentially received by members 

of the proposed class. 

7.2.1.1 Discussion of In Vitro Bioassay and Radionuclides 

Allen (1993) states that periodic urine and/or fecal samples were collected and analyzed for 

plutonium-238, plutonium-239, elemental uranium, uranium-234, uranium-235, uranium-238, 

americium-241, strontium-89, strontium-90, tritium, and gross fission products. Common in vitro

bioassays included: 
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 Tritium in urine by liquid scintillation beta counting, 

 Strontium in urine by beta counting, 

 Gross fission products in urine by beta counting, 

 Uranium in urine by fluorometric analysis, 

 Plutonium and americium in urine by alpha spectroscopy, and 

 Radium, uranium, plutonium, and americium in feces by alpha spectroscopy. 

NIOSH has documentation that fully describes the procedure, calibration, and interferences for each 

method used for bioassay, as well as documentation of all minimum detectable activities of the 

counting techniques. 

Tritium: Tritium urinalysis was performed at NTS as early as 1958 (LASL, 1954). The 1958 

tolerance for tritium in urine was listed as 85 μCi/L. In 1959, the maximum permissible concentration 

for tritium was listed as 1.2 mCi in the body, which yielded 0.1 rem per week. Records from 1966 to 

1968 show that tritium analysis was conducted with a liquid scintillation spectrometer. In 1971, the 

urine sample tritium “alert level” was listed as 1 × 10-3 μCi/cc (Unknown author, 1951-1973). 

Strontium: In 1961, the NTS laboratory published a sensitivity limit for strontium-90 in urine of 25 

pCi/sample (Unknown author, 1951-1973). Starting in 1993, gas-flow proportional beta counting was 

used to quantify strontium-90 in urine at NTS. That latter method had a minimum detectable activity 

of 0.8 pCi/L, but the method did not differentiate between strontium-89 and strontium-90. Strontium90 was monitored on a quarterly basis and as special, or occurrence, samples were taken. 

Fission Products: In addition to performing bioassay for strontium, NTS conducted gross beta and 

gross gamma urinalysis to determine intakes of mixed fission and activation products. The term 

“gross fission product” was used rather than “gross beta.” This analysis actually was used for all betaemitting radionuclides except the alkali group (e.g., cesium-134, cesium-137, and potassium-40) 

(Allen, 1993). The intent was to eliminate naturally occurring potassium-40 from the sample because 

the concentration of potassium in urine varies widely. By 1958, NTS was performing gross beta 

analysis by precipitating an aliquot and beta-counting the precipitate (Dummer, 1958). Depending on 

the beta result, a separate aliquot was used to prepare a sample for gross gamma-counting, using liquid 

scintillation (Dummer, 1958). In 1961, NTS analyzed urine samples for gross fission products before 

performing radionuclide-specific analyses (Geiger, 1961). Strontium, barium, lanthanide rare earths, 

and other fission products were co-precipitated with alkaline earth phosphate from an alkaline 

solution. The precipitate was assayed without further chemical treatment for total beta-emitters to 

obviate, in many cases, detailed radiochemical determination. If insignificant quantities of radioactive 

material were detected, no additional analyses were performed. Analyses for specific radionuclides 

could be requested if the gross beta activity exceeded the following control limits: 

 Exposure to fission product mixture less than three months old – control limit was 1.0 pCi/mL; 

and 

 Exposure to fission product mixture greater than three months or age unknown – control limit was 

0.1 pCi/mL. 
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All radionuclide-specific results that exceeded 20% of the control limit should have been recorded on 

the worker’s bioassay data card. It is possible that results equal to or less than 20% of the control 

limits were not recorded in the worker’s history. 

Specific analysis for cesium-137 in urine in 1961 involved sample preparation, cesiumphosphotungstate precipitation, and a specific gamma count (REECo, 1961). NTS used gamma-pulse 

height analyses to evaluate samples unless there was interference from higher-energy gamma-emitters, 

in which case NTS separated cesium as cesium-phosphotungstate, followed by pulse-height analysis. 

The sensitivity was listed as about 10 pCi per sample (REECo, 1961). In 1961, certain samples were 

examined with a gamma spectrometer to identify gamma-emitting components (REECo, 1961). 

Quantitative estimates were made in some cases. Special chemical separation schemes were devised 

as needed, based on the results of the initial pulse-height analysis. Reportedly, almost any gamma 

component could be identified by a combination of pulse-height analysis, chemical purification, and 

beta measurements. 

Uranium: NTS tested for intake of uranium as early as 1954 (LASL, 1954) using a fluorophotometric 

method, which measured the yellow-green fluorescence produced by traces of uranium fused in 

sodium fluoride. The fluorescence method was sensitive to concentrations of uranium from 10-5 to 5 

× 10-10 gram per 0.25 gram of sodium fluoride, with a precision of +10%. The tolerance for normal 

uranium in urine was 100 μg/L (LASL, 1954). An ion exchange method for separating uranium alpha 

activity in urine and counting was implemented in the late 1950s (Dummer, 1958). Using this 

method, it took three days to analyze nine samples (Dummer, 1958). Starting in 1958, NTS also used 

a uranium extraction method in which urine was ashed with nitric acid. Uranium was extracted from 

the acid and precipitated to platinum plates, fused, and counted for alpha particles using a lowbackground proportional counter. NTS could complete the analysis for about 25 samples in one day 

using this method (Dummer, 1958). NTS also performed an analysis for enriched uranium. The 

highly-enriched uranium analysis also used an alkaline co-precipitation of the uranium, but included 

several other wet chemistry steps. The resulting sample plate was analyzed by a gas flow proportional 

detector (Geiger, 1961). NTS also used a fecal analysis technique to monitor exposure to uranium235. 

Plutonium: NTS conducted urinalysis for exposures to plutonium as early as 1954 (LASL, 1954). 

Plutonium was co-precipitated with lanthanum fluoride on a stainless-steel plate and counted for alpha 

activity with a low-background proportional counter. Quantities on the order of 2 dpm or 2 × 10-11

gram of plutonium could be determined by this method. In 1961, NTS incorporated an anion 

exchange, electrodeposition method in which alpha tracks were counted (REECo, 1961; Unknown 

author, 1951-1973). Starting in 1968, alpha spectrometry was used to count plutonium-239 in urine 

samples (ORAUT-TKBS-0008-5, page 16) and the permissible bone burden for plutonium-239 was 

listed as 0.04 μCi (Unknown author, 1951-1973). Allen (1993) stated that plutonium urine and fecal 

samples were analyzed by alpha spectrometry, which could not differentiate between plutonium-239 

and plutonium-240. As a result, urine samples were also analyzed by gamma spectroscopy. The 

gamma spectroscopy method had a higher minimum detectable activity than that of alpha 

spectrometry (Bechtel Nevada, 2003). 
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Americium: Like plutonium, NTS conducted urinalysis for exposures to americium as early as 1954 

(LASL, 1954). Americium was co-precipitated with lanthanum fluoride on a stainless-steel plate. 

The plate was counted for alpha activity with a low-background proportional counter. In 1958, Los 

Alamos Scientific Laboratory used the same procedure for americium in urine and stated that thorium, 

plutonium, curium, actinium, and neptunium were carried through this determination. Quantities on 

the order of 0.5 dpm of americium could be detected by this method (ORAUT-TKBS-0008-5, page 

15). 

REECo documentation discussed an americium analysis method with steps for separation by 

precipitation/oxidation, purification by an ion exchange column, electrodeposition of americium241/243 on a stainless-steel disc, and detection by alpha spectrometry during the period from 1981 

through 1983. The procedure states that americium-241 was analyzed using americium-243 as a 

tracer. In 1993, the lower limit of detection for americium-241 was listed as 0.03 pCi/L with a note 

indicating that americium cannot be chemically differentiated from californium and curium (Allen, 

1993). The routine bioassay was a quarterly urine sample and the special bioassay consisted of an 

additional urine sample and a lung count. 

Radium: By 1958, NTS was using urinalysis to monitor for internal intakes of radium-226. Radium226 was used at NTS in calibration activities. Using wet chemistry, radium was co-precipitated with 

barium as the sulfate. Polonium was removed by deposition on silver foil. The precipitate was 

slurried onto a stainless-steel plate and the alpha activity counted using a methane flow proportional 

counter. A 24-hour sample was usually collected for radium analysis (Dummer, 1958). 

 

Special Fecal Analyses: Fecal sample analyses were conducted at NTS as a special bioassay, usually if 

there were indications that internal contamination had occurred or to confirm an intake of certain 

radionuclides (Allen, 1993). Fecal samples were analyzed by alpha spectroscopy for radium, 

uranium, thorium, plutonium, and americium (Allen, 1993; Bechtel Nevada, 2003). Alpha 

spectroscopy began in the late 1970s as a method of measurement. In the 1990s, some environmental 

projects to remediate plutonium-contaminated sites required periodic fecal bioassay (ORAUT-TKBS0008-5, page 22). 

7.2.1.2 Discussion of In Vivo Bioassay and Radionuclides

NTS performed the first in vivo analyses in 1961 when direct gamma counting was used to detect 

iodine-131 in worker thyroids. Counting procedures were written by REECo that document a method 

to analyze a worker’s thyroid when the worker’s urinalysis indicated exposure to radioiodine. By the 

procedure, nasal swabs were obtained to determine if the nose and mouth were contributing gamma 

activity and thereby falsely affecting the thyroid results. Thyroid counting was performed with the 

whole-body counting system by positioning the detector over the appropriate area and counting for 40 

minutes (Allen, 1993). 

In 1964, the Los Alamos Scientific Laboratory performed some in vivo analyses on NTS workers. 

NIOSH has no documentation to indicate where those analyses were performed. After that, Los 

Alamos Scientific Laboratory did use in vivo techniques at NTS to analyze potential intakes of 

employees who were assigned to NTS (Teasdale, 1985). The only significant time this procedure was 

used for NTS workers was during the YUBA incident (June 1963), but the information obtained was 

not included in the dose histories. 
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Helgeson Nuclear Services performed the first whole-body counting of REECo workers at NTS in 

1967. Helgeson used a shadow shield that was transported in a trailer. Helgeson performed in vivo 

analyses at NTS on three different occasions during 1966 through 1967 (ORAUT-TKBS-0008-5, page 

24). Some of the radionuclides, identified by body burden, are listed in Table 7-9. No information 

was provided indicating the type of job categories that were measured. 

Table 7-9: Number of Workers1 Receiving In Vivo Monitoring Before 1967 

Body Burden Nuclide 

< 0.02 μCi < 0.05 μCi < 0.1 μCi < 0.5 μCi 

Zirconium-Niobium-95 98 43 16 6 

Tantalum-182 102 17 3 1 

Ruthenium-103, -106 34 1 - - 

Barium-Lanthanum-140 26 2 - - 

Iodine-131 2 - - - 

Source: Adapted from ORAUT-TKBS-0008-5, page 25. 

Notes: 

Hyphen (-) indicates that data are not available. 

1 By nuclide concentration

In 1967, Pan American Airways introduced a whole-body counter at NTS to analyze potential intakes 

of workers involved with the NRDS (Teasdale, 1985). The ownership and operation of the wholebody counter was transferred to REECo in 1974. Routine in vivo analyses were performed by NTS 

(REECo) on drillers, miners, and radiation monitoring personnel beginning in mid-1975. In 1977, 

NTS considered adding lung counting for low-energy X-ray detection, but the additional technique 

was believed to be cost-prohibitive (ORAUT-TKBS-0008-5). A new in vivo facility was constructed 

and operated from February 1981 through 1999. NTS used whole-body counting to confirm and 

assess exposures from gamma-emitting radionuclides, as discussed in ORAUT-TKBS-0008-5. 

Workers were counted while sitting in a chair with the back reclining about 30 degrees from vertical 

position. That geometry yielded an arc with the detector of 50 cm between the back and seat, 

providing a full view of the body trunk in relation to the detector. Workers were normally counted for 

20 minutes by 1993. ORAUT-TKBS-0008-5 states that whole-body counts were performed for new 

employees who were likely to be included in the routine bioassay program; for a current employee 

who changed to a job classification that required a routine bioassay program; annually for employees 

who were currently on the routine whole-body count and bioassay program; for terminating 

employees; and for employees who had a suspected intake of radioactive material, particularly 

gamma-emitting fission and activation products (ORAUT-TKBS-0008-5, page 27).. 
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7.2.1.3 Air Monitoring Data and Documentation

Workplace air sampling was performed at NTS to monitor workplace conditions rather than to limit 

intakes of radionuclides; however, the air monitoring devices were positioned to provide samples 

representative of worker breathing zones. Workplace air monitoring was required in occupied areas 

that had the potential to exceed 10% of any Derived Air Concentration (DAC) value listed in DOE 

Order 5480.11 (DOE, 1988). NIOSH has access to a limited amount of air monitoring data associated 

with personnel and facility specific monitoring (excluding the ambient environmental monitoring 

described in Section 7.2.2.1) at NTS. Collection and research of these data has not been performed 

for this evaluation, so further review of its usefulness in assessing and bounding internal dose for the 

evaluated class is not included in this report. 

7.2.1.4 Radon

In the early 1980s, NTS recognized that the buildup of radon and radon daughter concentrations could 

pose a potential health problem in tunnels on Rainer Mesa and at other locations at the site. In 1984, 

Reynolds Electrical and Engineering Company, Inc. conducted radon measurement surveys in G-, T-, 

and N-Tunnels to determine the radon daughter concentration (Fauver, 1987). Other than radon and 

thoron that occurred naturally, NTS did not observe other operations that resulted in increased 

exposures. Radon daughter measurements performed in the N- and T-Tunnels were made in drifts 

that had been mined in a rock formation known as Tunnel Bed Non-Welded Ash Fall Tuff, which is 

mostly unconsolidated with slight fractures. The drift sampled in the inclined G-Tunnel was mined in 

Grouse Canyon Welded Ash Fall Tuff, which is extremely fractured. Concentrations of radon/radon 

daughters and subsequent measurements made in each of the tunnels were affected by the ventilation 

rate, the barometric pressures, the relative humidity, temperature inversions, the degree of fracturing 

in the rock, and the amount of smoke and dust in the air. The concentration of radon daughters in air 

is measured in units of working levels (WL). The WL was developed for use in uranium mines, but is 

now also used for environmental exposures. One (1) WL is equal to any combination of short-lived 

decay products in 1 liter (L) of air that will result in the emission of 1.3 × 105

 MeV of potential alpha 

energy. Assuming that radon is in complete equilibrium with its short-lived decay products, 1 WL 

equals 100 pCi L-1 (i.e., 100 pCi/L each of radon-222 and short-lived decay products polonium-218, 

lead-214, bismuth-214, and polonium-214) (ORAUT-TKBS-0008-4, page 41). When considering 

exposure to radon-220 (thoron) and its decay daughters of polonium-216, lead-212, bismuth-212, and 

thallium-208, 1 WL is equal to 7.47 pCi/L. The advantage of the WL unit is that it allows comparison 

of different equilibrium levels and different concentrations of radon decay products. The degree of 

equilibrium is a critical factor for estimating inhalation exposure and is of equal importance to the 

radon concentration itself (ORAUT-TKBS-0008-4, page 41). The exposure of tunnel workers can be 

expressed in units of working-level months (WLM), which is an exposure rate of 1 WL for a working 

month of 170 hours (ORAUT-TKBS-0008-4, page 41). For example, an exposure of 1 WLM would 

result from exposure to a concentration of 1 WL for one month or 0.5 WL for two months. 
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Measurements taken in tunnels N, T, and G indicated ranges from 0.001 WL to as high as 0.24 WL. 

The higher values were observed when tunnel ventilation rates were noted to be low (ORAUT-TKBS0008-4). The radon daughter concentrations in G Tunnel were an order of magnitude higher than 

those in N and T Tunnels. The average radon daughter concentration in the rock mechanics drift, 

which was found to be the worst case, was 0.13 WL. NTS performed additional radon and thoron 

measurements in 1991 and 1992 in G-, N- and P-Tunnels (Lyons, September 1992, November 1992). 

While the G-Tunnel complex was not used for production operations during 1992, radon samples 

were taken to document potential radon WL for a worst-case scenario of complete ventilation failure 

throughout the complex. The maximum WL for radon daughters was 1.4. No samples were taken 

during 1992 in T-Tunnel, which was inactive that year. Results of extensive radon sampling in N- and 

P-Tunnel complexes in 1991 and 1992 are provided in Tables 7-10 and 7-11 (Lyons September 1992, 

November1992). The average concentrations in N- and P-Tunnels were 0.021 and 0.009 WL, 

respectively, and the maximum concentrations in N- and P-Tunnel were 0.038 and 0.017 WL, 

respectively. 

Table 7-10: Radon/Thoron Daughter Concentrations for N-Tunnel in 1991 and 1992 

Radon-222 WL Radon-220 WL 

N Tunnel location 

Average Maximum Average Maximum 

January–June 1992

Miner's Lunchroom 0.005 0.007 0.01 0.016

Raytheon Alcove 0.003 0.004 0.005 0.008

Slow Alcove 0.005 0.007 0.008 0.009

24 Bypass Drift 0.005 0.006 0.015 0.015

24 LOS Drift at GZ 0.005 0.007 0.012 0.014

22 Bypass 0.006 0.007 0.013 0.015

July–December 1991

Miner's Lunchroom 0.005 0.007 0.011 0.018

Raytheon Alcove 0.009 0.03 0.017 0.06

21 LOS at 2 + 50 0.034 0.059 0.029 0.046

15 Assembly Drift 0.006 0.009 0.015 0.021

Slow Alcove 0.004 0.008 0.01 0.025

23 Fast Alcove 0.009 0.014 0.018 0.03

24 Bypass Drift 0.005 0.007 0.012 0.041

24 LOS Drift 0.005 0.01 0.015 0.036

Average 0.008 0.013 0.014 0.025
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Table 7-11: Radon/Thoron Daughter Concentrations for P-Tunnel in 1991 and 1992 

P-Tunnel location Radon-222 WL Radon-220 WL 

Average Maximum Average Maximum 

January–June 1992

01 Drift at Access Drift 0.001 0.001 0.002 0.005 

01 Fast Alcove 0.001 0.001 0.004 0.006 

02 Main Drift at 6 + 00 0.001 0.001 0.002 0.004 

04 Reentry 0.001 0.002 0.004 0.005 

04 LOS at 12 + 00 0.002 0.002 0.005 0.006 

HPD Base Station 0.001 0.001 0.003 0.006 

Miner's Lunchroom 0.001 0.001 0.003 0.006 

05 Cavity 0.001 0.001 0.003 0.004 

July–December 1991 

01 Drift at Access Drift 0.003 0.006 0.004 0.007 

01 Fast Alcove 0.003 0.005 0.003 0.006 

02 Main Drift at 6 + 00 0.01 0.032 0.01 0.046 

04 LOS at VP X-Cut 0.008 0.013 0.012 0.015 

04 LOS Drift at GZ 0.005 0.006 0.014 0.02 

04 LOS Test Ch. 0.003 0.004 0.005 0.006 

04 Bypass at RE#1 0.007 0.013 0.008 0.011 

IHD Alcove 0.003 0.009 0.004 0.015 

LLNL Alcove 0.003 0.006 0.007 0.02 

05 Cavity 0.003 0.006 0.006 0.015 

Average 0.003 0.006 0.006 0.011 

7.2.2 Ambient Environmental Internal Radiation Doses at NTS 

In total, more than 900 nuclear tests have taken place at NTS. One result of these tests is that the 

surface soil in many parts of NTS contains measurable amounts of several long-lived radionuclides. 

Almost all of the more than 100 above-ground tests contaminated the soil near ground zero. In 

addition, several underground tests were cratering experiments that threw radioactive rock and soil 

hundreds of feet, while some deeper underground tests vented radioactive material to the surface. A 

few safety tests scattered plutonium (and in some cases uranium) over the nearby ground. Finally, 

there was fallout of radioactive debris from many tests over the northern and eastern parts of the site. 

The greatest potential for environmental intakes of radioactive materials at NTS is the inhalation or 

ingestion of resuspended environmental contamination (ORAUT-TKBS-0008-4). 

Atmospheric weapon and safety tests from 1951 through 1962 released approximately 1.2 × 1010 Ci to 

the atmosphere, much of which was from relatively short-lived radionuclides that decayed in a matter 

of days or weeks. In comparison, underground weapons testing released approximately 2.5 x 107

 Ci 

to the atmosphere from 1958-1988 (with only 5.4 x 104 Ci being released between 1971 and 1988) 

(ORAUT-TKBS-0008-2). The volatile radionuclides (such as radioiodines, noble gases, and tritium) 

were diluted in the atmosphere and transported offsite. However, a large amount of the nonvolatile, 

long-lived radionuclides settled into the soil across the site (ORAUT-TKBS-0008-4, page 8). 

Environmental contamination has also occurred from releases of radionuclides from the low-level 

radioactive waste sites in Area 3 and Area 5. These releases have involved all radionuclides (other 
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than short-lived fission products) handled at NTS and have affected each of the environmental 

pathways. 

7.2.2.1 Ambient Environmental Radiation—Air Sampling

In 1964, REECo established an environmental surveillance program at NTS designed to measure 

radiological conditions throughout the site without regard to nuclear tests. The short-term objective of 

the program was to minimize casual personnel exposure to radiation by locating and identifying 

localized radiological environmental conditions by type and quantity of contamination. The 

long-range objective of the program was to establish baseline environmental data that could provide a 

reference for comparison with subsequent test activities and radiation measurements. The initial 

surveillance program grew to include, over time, 12 permanent air-sampling stations in the most 

populated areas at NTS (ORAUT-TKBS-0008-4, page 10). 

After the first reporting period (June 1964), the number of sampling stations increased to 13 and 

caustic scrubbers were added to detect radioiodines. Early particulate samples were typically 

analyzed only for gross alpha and gross beta by gas-proportional counting. However, if gross beta 

concentrations exceeded 1 × 10-5 μCi/m3

, researchers conducted an analysis for actinium-227 (the 

most hazardous beta emitter present). Because no historical evidence exists that actinium-227 has 

been detected in air or soil samples, the assumption that unidentified beta emitters were actinium-227 

would be unreasonable and inappropriate. Therefore, for purposes of dose reconstruction, strontium90 is assumed to be the unidentified beta-emitting radionuclide with the highest internal dose 

(ORAUT-TKBS-0008-4, page 10). 

Gross gamma screening was also typically performed on samples prepared for gross beta counting. 

The screening procedures are described in more detail in ORAUT-TKBS-0008-4. After atmospheric 

testing at NTS ended in 1962, fission products were frequently measured in the atmosphere but were 

typically correlated with foreign atmospheric weapons testing. 

In 1971, weekly air samples from given stations were batched on a monthly basis and analyzed for 

plutonium-239. This analysis provided a nominal minimum detection limit of 3 × 10-7 μCi m-3

(ORAUT-TKBS-0008-4, page 11). Routine analysis of batched samples for plutonium-238 was 

implemented in 1989. 

In 1977, a separate sampler was designed to collect airborne tritium and tritiated water vapor. The 

sampler was portable and capable of unattended operation for up to two weeks in desert areas. 

7.2.2.2 Ambient Environmental Radiation—Soil Sampling

NTS performed extensive characterizations of residual contamination of soils and areas in the 1980s 

(McArthur, 1983, 1985, 1987, 1988, 1989, 1991). Table 7-12 lists the results of these studies. Table 

7-13 lists the total area depositions, which are based on the inventory values in Table 7-12 divided by 

the respective area size. It should be noted that the results shown in Table 7-13 are representative of 

areas of NTS shown to contain measurable levels of contamination. This area actually represents only 

about one-third of the total area within the boundaries of NTS. 
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Table 7-12: Inventory of Contaminated Soil, Curies 

Area Area 

(mi2) Am-241 Pu-238 Pu-239, Pu-240 Co-60 Cs-137 Sr-90 Eu-152 Eu-154 Eu-155 

1 26.5 4.2 6.5 24 1.1 8.8 15 15 0.1 0.5 

2 19.7 2.9 8.6 22 1.2 24 46 14 - 0.4 

3 32.3 4.6 3.1 37 1 12 33 18 0.1 0.5 

4 16 6.6 13 40 1.6 12 13 9.1 - 0.2 

5 2.9 0.6 0.1 4.8 0.6 0.4 0.9 10 0.2 0 

6 32.3 1.7 3.3 8.4 0.2 2.8 3.5 - - 0 

7 19.3 2.2 0.6 16 1 5.2 9.2 22 0.2 0.3 

8 13.9 17 8 110 5.7 42 25 4.4 0.6 

9 20 4.2 2.2 89 0.7 8.7 13 23 0.2 0.3 

10 20 19 19 110 9.7 84 55 2.2 0.3 5 

11 4 3.3 0.5 29 0 0.5 0.3 - - -

12 39.6 5.7 8.5 39 1.2 20 17 - - -

15 35.3 8 7.8 63 0.3 19 22 - - -

16 14.3 0.7 1.5 3.7 0.1 2.9 3.7 - - -

17 31.4 2.8 4.5 18 1 15 19 - - -

18 27.3 19 5.6 100 0.7 10 17 1.1 0.1 0.8 

19 148.3 21 32 140 1.1 36 31 - - -

20 6.2 23 30 41 7.9 5.5 4.3 13 1.6 4.8 

25 0.9 - - - - 0.2 0.1 0.4 - -

26 0.2 - - - - - - - - -

30 .0.3 3.2 4.5 14 0.8 1.5 1.3 0.7 0.1 0.2 

Notes: 

Source: McArthur, 1991 

Hyphen (-) means no data are available 

Table 7-13: Radionuclide Area Soil Deposition (Bq/m2) 

Area Am-241 Pu-238 Pu-239, 

Pu-240 Co-60 Cs-137 Sr-90 Eu-152 Eu-154 Eu-155 

1 2.26E+03 3.50E+03 1.29E+04 5.93E+02 4.74E+03 8.09E+03 8.09E+03 5.39E+01 2.70E+02 

2 2.10E+03 6.24E+03 1.60E+04 8.70E+02 1.74E+04 3.34E+04 1.02E+04 0.00E+00 2.90E+02 

3 2.03E+03 1.37E+03 1.64E+04 4.42E+02 5.31E+03 1.46E+04 7.96E+03 4.42E+01 2.21E+02 

4 5.89E+03 1.16E+04 3.57E+04 1.43E+03 1.07E+04 1.16E+04 8.13E+03 0.00E+00 1.79E+02 

5 2.96E+03 4.93E+02 2.36E+04 2.96E+03 1.97E+03 4.43E+03 4.93E+04 9.85E+02 0.00E+00 

6 7.52E+02 1.46E+03 3.72E+03 8.85E+01 1.24E+03 1.55E+03 0.00E+00 0.00E+00 0.00E+00 

7 1.63E+03 4.44E+02 1.18E+04 7.40E+02 3.85E+03 6.81E+03 1.63E+04 1.48E+02 2.22E+02 

8 1.75E+04 8.22E+03 1.13E+05 5.86E+03 4.32E+04 2.57E+04 4.52E+03 0.00E+00 6.17E+02 

9 3.00E+03 1.57E+03 6.36E+04 5.00E+02 6.21E+03 9.29E+03 1.64E+04 1.43E+02 2.14E+02 

10 1.36E+04 1.36E+04 7.86E+04 6.93E+03 6.00E+04 3.93E+04 1.57E+03 2.14E+02 3.57E+03 

11 1.18E+04 1.79E+03 1.04E+05 0.00E+00 1.79E+03 1.07E+03 0.00E+00 0.00E+00 0.00E+00 

12 2.06E+03 3.07E+03 1.41E+04 4.33E+02 7.22E+03 6.13E+03 0.00E+00 0.00E+00 0.00E+00 

15 3.24E+03 3.16E+03 2.55E+04 1.21E+02 7.69E+03 8.90E+03 0.00E+00 0.00E+00 0.00E+00 

16 6.99E+02 1.50E+03 3.70E+03 9.99E+01 2.90E+03 3.70E+03 0.00E+00 0.00E+00 0.00E+00 

17 1.27E+03 2.05E+03 8.19E+03 4.55E+02 6.82E+03 8.64E+03 0.00E+00 0.00E+00 0.00E+00 

18 9.94E+03 2.93E+03 5.23E+04 3.66E+02 5.23E+03 8.90E+03 5.76E+02 5.23E+01 4.19E+02 

19 2.02E+03 3.08E+03 1.35E+04 1.06E+02 3.47E+03 2.99E+03 0.00E+00 0.00E+00 0.00E+00 

20 5.30E+04 6.91E+04 9.45E+04 1.82E+04 1.27E+04 9.91E+03 3.00E+04 3.69E+03 1.11E+04 

25 0.00E+00 0.00E+00 0.00E+00 0.00E+00 3.17E+03 1.59E+03 6.35E+03 0.00E+00 0.00E+00 

26 0.00E+00 0.00E+00 0.00E+00 0.00E+00 0.00E+00 0.00E+00 0.00E+00 0.00E+00 0.00E+00 

30 1.52E+05 2.14E+05 6.67E+05 3.81E+04 7.14E+04 6.19E+04 3.33E+04 4.76E+03 9.52E+03 
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7.2.2.3 Statistical Modeling of Environmental Data for Dose Reconstruction

With atmospheric testing at NTS ending in 1962, the greatest potential for environmental intakes of 

radioactive material became the inhalation of radioactive particles re-suspended into the atmosphere 

and the ingestion of soil previously contaminated by atmospheric nuclear weapons tests and safety 

tests. NIOSH has developed an ambient environmental data model using NTS annual environmental 

air monitoring data, as discussed in Section 7.2.2.1, and the extensive soil contamination data gathered 

between 1983 and 1991 for use in reconstructing internal doses for NTS employees. The data used to 

develop the model have been professionally critiqued in the Health Physics Journal and several DOE 

reports (Fauver, 1987; Hicks, 1981a, 1981b, 1981c, 1981d; Kinnison, 1997; Lyons September 1992, 

November 1992; McArthur, 1983, 1985, 1987, 1988, 1989, 1991; Scoggins, 1983; Wruble, 1990). 

 

Air monitoring was limited to analysis of gross alpha and beta measurements, tritium, and isotopes of 

plutonium (e.g., plutonium-238, plutonium-239, and plutonium-240); the model was developed to 

include inhalation intakes of other relatively long-lived radionuclides identified in NTS soil, including 

americium-241, cobalt-60, cesium-137, strontium-90, europium-152, europium-154, and europium155. Intakes of those latter radionuclides were scaled to those of plutonium based on their relative 

abundance in NTS soil. Ingestion intake factors were estimated by assuming consumption of the 

contaminated NTS soil. To ensure that both inhalation and ingestion intakes are not underestimated, 

the relative abundance of the long-lived radionuclides identified in NTS soil, as determined using the 

1991 soil contamination data (McArthur, 1991), were decay-corrected back to 1963. In addition, to 

ensure that intakes and resultant doses were not underestimated, correction factors were developed to 

account for potential exposures to short-lived fission and activation products based on test-specific 

data provided by Hicks. Finally, a correction factor was added to the model for inhalation intakes, 

which account for the phenomenon of early re-suspension and mass loading (Anspaugh, 2002). The 

model also incorporates area-specific inhalation and ingestion rates for use when worker’s work 

locations are known. The resulting intake rates are supported by resuspension and air concentration 

studies performed in the early 1980s that are applicable to work performed outdoors in soil 

contaminated areas, which showed low air concentrations even after soil disturbances (McMahon, 

2003). These studies indicated the highest concentrations were less than 2% of the current derived air 

concentrations after disturbing soils contaminated with plutonium and americium in the hundreds of 

pCi/g levels. 

The derived ambient model was developed to address the unique character of NTS—a large outdoor 

testing facility where potential exposure to radioactive materials was primarily based on residual 

contamination from atmospheric testing—and to augment the lack of internal monitoring data for 

some radionuclides. For most NTS employees, the occupational internal dose can be equated to the 

dose they potentially received from the re-suspension of residual radioactivity from the atmospheric 

testing (i.e. environmental internal dose). For workers who worked primarily indoors (cafeterias, 

administrative facilities, and maintenance shops) the internal dose calculated from the model 

represents an overestimate of any actual internal exposure. 

Some covered employees stayed onsite continuously for weeks at a time. NIOSH finds that the intake 

values would provide overestimates for these resident employees as well. Most workers spent a 

considerable portion of the non-working hours indoors (sleeping, etc.) where ambient air particulate 

loadings would have been greatly reduced from the outdoor loadings. The model uses the following 

assumptions: (1) radionuclides fractions were modeled using maximum plutonium annual air 
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concentration measured for all NTS areas between 1971 and 2001; (2) radionuclide scaling factors 

were based on the highest ratio of soil contamination to plutonium-239 of each of the radionuclides in 

any of the NTS areas; and (3) fission product intake rates were based on data intakes calculated using 

short-lived fission and activation product data obtained during from the Storax Small Boy test, which 

provided the highest fission product doses. Additionally, employees living onsite during their work 

week would have been housed in Area 12 or Area 23 (Mercury) where air sampling results were less 

than the NTS site average values. Details, including mathematical and statistical derivations, are 

provided in Rollins, 2007. 

7.2.3 Internal Dose Reconstruction Considerations 

NIOSH’s intent in the original revision of the SEC00084-NTS evaluation report was to use the 

bioassay monitoring data from 100 claimants with the highest external exposure to construct a coworker model that could be used to bound chronic internal exposures to unmonitored workers. In 

their review of this proposed approach, SC&A raised some significant issues that could not be 

adequately addressed without either further review of NTS site documentation and/or review of 

additional bioassay results. To this end, NIOSH undertook an additional review of the health physics 

program documents underlying the bioassay monitoring program and also obtained and reviewed the 

complete set of electronic bioassay records from NTS to determine if these records provided sufficient 

additional information to address some of the apparent shortcomings in the bioassay data previously 

available to NIOSH. 

Analysis of Issues of Concern

For a co-worker study to bound the internal doses potentially incurred by unmonitored workers, 

NIOSH must be able to address adequately the following issues that are unique to NTS operations: (1) 

how the varying job titles/duties and work activities were considered in the basis for NTS bioassay 

monitoring; (2) bioassay data gaps that exist for certain radionuclides and time periods; (3) the nature 

and expanse of the work performed at NTS; and (4) the wide variety of radionuclides present at NTS. 

A summary of the status of these issues is provided below. 

1. NIOSH has identified exposure scenarios involving varying job titles/duties and work activities, 

such as drill-backs, post-test work activities, and construction or other soil-disturbing activities in 

areas that had been contaminated by previous tests. Prior to 1993, no source documentation could 

be located to confirm the rationale behind why bioassay samples were collected. Because of this, 

NIOSH cannot conclusively determine that doses to all of these potentially-exposed individuals 

were detected by the bioassay program. 

A review of the available data indicates that a large number of radiological technicians and 

security personnel were routinely sampled. Other job titles/duties are also represented but a 

substantial fraction of the ‘other’ group of bioassay samples appears to have been collected on a 

more event or incident-driven basis. Although NIOSH does have access to site procedures and 

directives, NIOSH has not located sufficient documented evidence, other than anecdotal 

information, to describe a consistent rationale behind the collection of personnel bioassay samples 

or to indicate that sampling occurred consistently in the situations where it was required. 
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2. NIOSH has identified data gaps that exist in the electronically-available bioassay data for certain 

radionuclides and time periods. Below are some examples of data gaps that impact NIOSH’s 

ability to bound internal dose: 

• Specific radionuclide analyses for fission products are not available to NIOSH. Rather, the 

bioassay data available for assessing fission product exposures are more generally listed as 

gross beta analyses. Given that fission products were the most likely source of potential 

exposure and the make-up of the fission products source-term was project- and 

time-dependent, this brings into question the ability to reconstruct a representative distribution 

of NTS fission product exposures during this time period. 

• NIOSH identified only 300 bioassay records for uranium up to the year 1992. While it may be 

that there was a limited potential for exposure to uranium, and 300 bioassay results could be an 

appropriate number, NIOSH has not located sufficient documentation to support or refute that 

possibility. 

• As in the case with uranium, NIOSH has identified that the number of workers monitored for 

plutonium appears to be small (e.g., fewer than 200 from many years) considering the size of 

the NTS workforce. While it can be argued that few people were monitored because of the 

low potential for exposure, the evidence in the database (i.e., a large number of positive Pu 

results) confirms that there was clearly a source term for plutonium capable of producing 

measurable intakes. 

3. The nature of NTS work and the large geographic area over which this work was conducted 

presents a unique challenge for bounding the internal doses. Unlike many production sites (i.e. 

SRS, Rocky Flats, Fernald), the NTS was primarily engaged in shorter-term, campaign-driven 

activities that were separated by large distances; there appears to be a direct relationship between 

campaigns and bioassay sampling. The concept of a campaign-driven bioassay sampling program 

is further supported by the fact that many of the periodic bioassay samples appear to have been 

collected on the same day. Because of the episodic nature of NTS exposures, a co-worker model 

that is useful in reconstructing chronic intake scenarios would not necessarily be representative of 

the exposure patterns of the NTS workforce.

4. The reconstruction of NTS internal doses is also complicated by the variety of the radionuclides to 

which workers may have been exposed. As indicated in the NTS Site Profile, the potential 

radionuclide source term included (but is not limited to): plutonium, americium, uranium, thorium, 

radium, iodine, and other fission products. For workers with no bioassay records, and who had the 

potential for exposure, NIOSH would have to definitively establish the relative mixture of the 

exposure source term. 

Although NIOSH has identified significant issues impacting its ability to bound doses for evaluated 

class during the period evaluated in this report, NIOSH does believe that sufficient information and 

monitoring data do exist to support bounding personnel doses after the cessation of all NTS nuclear 

testing in 1992. NIOSH has identified documentation that supports the basis for a sufficient post1992 bioassay program. The 1993 NTS document, Technical Basis for Internal Dosimetry at the 

Nevada Test Site (NTS, 1993) demonstrates NTS compliance with 10 C.F.R.835, describes the 

monitoring program and the analytical techniques for measuring the bioassay samples, defines the 
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potential exposures at various operations, and includes the types of occupations/work areas that must 

be bioassayed in order to ensure that workers with potential to exceed 100 mrem in a year are 

monitored. This document corresponds with the end of testing and associated post-shot activities. 

7.2.4 Internal Dose Reconstruction Feasibility Conclusion 

Upon completion of this review, there are still remaining data gaps and concerns associated with NTS 

internal monitoring data that bring into question NIOSH’s ability to bound all NTS internal exposures. 

NIOSH believes that there is insufficient information to adequately support bounding internal dose 

(reconstructing internal dose with sufficient accuracy) for the portion of the SEC-00084 NTS class 

who worked during the period of testing from 1963 through 1992. NIOSH believes that the cessation 

of all nuclear testing, coupled with the implementation of the 1993 NTS internal technical basis 

document that demonstrates NTS compliance with 10 C.F.R. 835 (NTS, 1993), supports NIOSH’s 

ability to bound internal dose at NTS starting in 1993. 

7.3 External Radiation Doses at NTS 

The principal source of external radiation doses for members of the proposed class are described in 

Section 5 of this report. As documented in ORAUT-TKBS-0008-6, the most plausible external 

radiological exposure scenarios were directly due to residual radioactive contamination from 

atmospheric and underground weapons testing, exposure due to experimental reactor tests intended for 

aircraft and rocket propulsion, and exposure to fission and activation products from test programs 

(ORAU-TKBS-0008-6, page 9). Occupational external exposures could have included beta, gamma, 

and neutron radiation, as well as X-rays from required periodic medical examinations. 

7.3.1 Process-Related External Radiation Doses at NTS 

The following subsections summarize the extent and limitations of information available for 

reconstructing the process-related external doses of members of the proposed class. 

7.3.1.1 Radiation Exposure Environment

NTS workers potentially received occupational exposures from a range of fission and activation 

products from test programs that were conducted in the early 1950s. The potential external radiation 

exposures arose primarily from the fission and activation products handled at NTS. In addition, there 

is a limited potential for neutron exposure from handling transuranic radionuclides, isotopic sources, 

and reactor operations. 

The external dose received by workers at NTS was a function of the physical location of the workers 

on the site, the work they were involved with, and when they were present onsite relative to the 

different tests. The analyses of the drillback cores of some shots show a high abundance of activation 

products and others show mostly fission products. 

In April 1957, NTS began a universal external monitoring program, requiring all employees to wear, 

at a minimum, a film dosimeter for measuring radiation exposure. The external exposure of concern 

at NTS was primarily due to beta and photon radiation-emitting nuclides. 
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Beta and Photon Characterization

The beta and photon radiation at NTS is characterized in ORAUT-TKBS-0008-2 and ORAUT-TKBS0008-6. 

As discussed in Section 5.3.4 of this report, most of the 250 individual fission-produced radionuclides 

are beta-particle emitters. The composition and beta-energy spectrum subsequent to a test is not 

constant, but for the beta produced by the decay of fission and activation products, the maximum 

energy typically does not exceed 3 MeV (ORAUT-TKBS-0008-6). Exposure to beta particles with 

energies below 70 keV imparts no beta dose to the skin because beta particles with energies below 70 

keV have insufficient energy to penetrate the keratinized dead outer layer of the skin; therefore, the 

beta energy range of concern is from 70 keV to 3 MeV. 

As further discussed in Section 5.3.4, the residual photon radiation intensity depends on a number of 

factors that vary from test to test, but relatively few radionuclides comprise the significant 

contributors to the photon spectrum. The photon energy spectrum then depends on the relative 

abundance of each of the radionuclides present in the area. At NTS, the radiation field is primarily 

comprised of photons with energies between approximately 100 keV and 2 MeV (ORAUT-TKBS0008-6). The special case of exposure to noble gases during post-test drilling can include a significant 

increase in the exposure to photons with energies below 100 keV (ORAUT-TKBS-0008-6). 

Neutron Field Characterization

The potential for neutron exposure at NTS has been limited since the start of site operations. 

Operations involving potential neutron exposures are classified as weapons-related, isotopic neutron 

source-related, or reactor operations-related. Section 5.3.3 of this report and ORAUT-TKBS-0008-6 

provide more detailed information regarding the potential for neutron exposure at NTS. 

Design Laboratory workers in the vicinity of sealed pits (those not associated with high explosives 

were known as “bare pits”) were potentially exposed to neutrons emanating from the pits. Dose 

records for Design Laboratory employees were routinely reported to the sponsoring laboratory and are 

available to NIOSH on an individual basis. All NTS exposures relating to assembly operations can be 

assessed on a case-by-case basis, using any available dosimetry data and, as necessary, geometrical 

correction factors and neutron-to-photon dose ratio techniques derived from DOE complex experience 

with weapons assembly operations. 

Workers involved with isotopic neutron sources or with reactor operations were monitored through 

the use of personnel neutron dosimeters. Additional information regarding the neutron fields that 

workers were potentially exposed to is available to NIOSH. There is no indication that neutronspectral measurements were conducted at NTS for radiation protection purposes; however, the 

International Atomic Energy Agency (IAEA) has compiled extensive neutron-spectral functions, 

instrument and dosimeter response functions, and dosimetric quantity response functions. Because 

the source spectra for NTS operations are limited to those discussed previously in this section, it is 

possible to adequately determine the spectra by selecting the proper neutron production mechanism, 

moderation conditions, and scatter conditions from the spectral catalogs that best simulate those 

conditions for NTS operations. 
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7.3.1.2 History of Whole-Body External Monitoring

Radiation monitoring and control programs instituted from the beginning of NTS operations included 

personal dosimetry, area monitoring, source term characterization, and measurements of fallout 

dispersion (contamination). As NTS test programs progressed, efforts to measure radiation exposures 

and limit dose improved. Universal dosimetry badging, in the form of film badges, was instituted at 

NTS in April 1957, and film badges were routinely issued to all persons entering and working at the 

site. Film badges were exchanged routinely for all individuals and, in addition, upon existing 

radiation areas if an exposure of 100 mR or more was suspected. In addition to film badges, selfreading pocket dosimeters were issued to persons entering controlled radiation exclusion (radex) 

areas, which were controlled locations at which an exposure was usually expected. The purpose of 

issuing pocket ionization chambers to persons entering a radex area was to provide an action alert. A 

high reading of a pocket ionization chamber triggered the action of collecting and processing the 

personnel dosimeter being used at the time. Pocket ionization results were not used to assign dose to 

an individual’s record unless the personnel dosimeter integrity had somehow been compromised. The 

pocket ionization chamber result would have been included in a special investigation of the incident. 

Only a small percentage of the workers at NTS were potentially exposed to neutron radiation and this 

exposure would typically be accompanied by beta and photon radiation. For workers involved in 

work areas with a possibility of neutron exposure, personnel neutron dosimeters (Kodak NTA film 

badges, Albedo dosimeters, or Track Etch Detector dosimeters) were used to monitor exposure. 

Because of the energy dependence of the various personnel neutron dosimeters used at NTS and 

throughout the DOE complex, the detection limits for neutron dosimeters are dependent on the 

operational neutron spectra encountered. ORAUT-TKBS-0008-6 contains information regarding the 

neutron spectra associated with the specific activities having the potential for occupational neutron 

exposure. 

Until the 1966 change to the DuPont Type 556 film pack, the determination of shallow or skin dose by 

reading the film badges was limited to higher-energy radiation because of the thickness of the lead 

filter. 

For more complete information regarding the history of personnel whole-body monitoring, refer to 

ORAUT-TKBS-0008-6. 

7.3.1.3 History of Extremity Monitoring

Extremity dosimetry has been used at NTS to assess exposure to fingers, hands, forearms and even the 

head (on rare occasions, recognizing that the head is not considered to be an extremity) that might 

have occurred during operations in proximity to, or the manual manipulation of, radioactive material 

and radiation-emitting objects. Few operations at NTS would require extremity monitoring. An 

example of a NTS worker requiring extremity monitoring might include a radiation technician 

involved in handling post-test core samples. 
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The dosimeter (film or thermoluminescent dosimeter) was worn in a position that was intended to 

represent the highest exposure to the extremity, usually on the inside of the wrist in the case of film, or 

on the finger near the fingertip in the case of finger rings. The extremity being monitored is normally 

identified in the dose record using the codes shown in ORAUT-TKBS-0008-5, Table A-2. 

The regular use of thermoluminescent dosimeter finger rings was documented in 1967 (ORAUTTKBS-0008-6, page 30). Extremity monitoring occurred on rare occasions prior to that time 

(ORAUT-TKBS-0008-6). 

Further information on the extremity monitoring program at NTS, as well as guidance on how to treat 

the dose recorded, is available in ORAUT-TKBS-0008-6). 

7.3.1.4 Dosimetry Records

As discussed in Section 6.0 of this document, NTS used facility and individual worker monitoring 

methods to measure and control radiation exposures. Hardcopy radiation exposure records and film 

from dosimeters are available from NTS. NTS undertook a considerable effort to consolidate all 

dosimetry records in what was originally called the Dosimetry Research Project (DRP) (now known 

as the Nuclear Testing Archive) (Personal Communication, 2005). 

7.3.1.5 Application of Co-Worker Data for External Dose Reconstruction

NTS employed a universal badging procedure in April 1957, making co-worker studies for external 

dose reconstruction after that time unnecessary. 

7.3.2 Ambient Environmental External Radiation Doses at NTS 

All workers at NTS were monitored for external radiation exposures (as discussed in Section 7.3). 

Ambient doses resulting from exposures to beta particles and photons were recorded on employee film 

badges/dosimeters. The geometry used for dosimeter calibration (which is more representative of the 

occupational Anterior-Posterior (A/P) exposure geometry for radiological workers) is likely very 

different from that associated with external environmental exposures. Environmental radiation 

sources are generally highly extended and isotropic as compared to the point sources placed near the 

dosimeter for calibration. The dose assessment for external environmental exposures requires that 

attention be given to the angular/directional dependence of the dosimeter, the angular/directional 

dependence of the dosimetric quantity used for monitoring purposes, and the dose of specific organs 

relative to the location of the dosimeter. Environmental exposures at NTS are characterized by 

complex photon spectra due to the presence of a large number of fission and activation product 

radionuclides. The energy spectrum is further complicated by the attenuation of lower-energy photons 

by both soil and distance from the source. These considerations relative to external environmental 

exposures at NTS have been evaluated and addressed for dose reconstruction using data on angular 

dependence of dose conversion factors. Calculations of the correction factors for organ geometry 

relative to the dosimeter have been performed for exposure to 1) fallout from atmospheric tests, 2) 

radionuclides released by underground test leaks, and 3) nuclear rocket and ramjet tests for exposures 

from time of test to 50 years following the test (ORAUT-TKBS-0008-6, page 46). ORAUT-TKBS0008-6 notes that the radionuclide and geometry-dependent dose conversion factors were taken from 

Eckerman et al. (1999). Results of these calculations show that the correction factors for 

environmental radiation fields found at NTS are not significantly different from unity for most organs; 
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these values are less than 1. Given the low environmental external exposure rates at NTS, it appears 

that the new DCFs would not have a significant impact on the assigned environmental doses in 

comparison to the NIOSH dose reconstruction estimates (ORAUT-TKBS-0008-6, page 46). 

As there are no unmonitored employees receiving unmonitored environmental external dose, further 

consideration of environmental external dose is not necessary. 

7.3.3 NTS Occupational X-Ray Examinations 

Diagnostic X-ray procedures contributed to the occupational radiation exposure of NTS workers. In 

general, the dose from these exposures was not measured, considered, or included as part of the 

overall occupational exposure of the employee, although it was clearly related. The passage of 

EEOICPA recognized diagnostic medical X-rays administered in conjunction with routine or special 

physical examinations required for employment as a valid source of occupational exposure. 

Unlike occupational exposures incurred during normal work processes, individual diagnostic medical 

X-ray exposures were not actively monitored, necessitating reconstruction of these exposures. NTS 

practiced universal badging, whereby employees received film badges on arrival at the Mercury gate 

for work. In some instances, workers wore those badges during initial employment physicals, which 

included routine posterior-anterior and lateral chest x-rays. Examination of these badges provided 

measured doses for those chest X-rays. 

Extensive review of available documentation on the occupational medical program at NTS from 1951 

to the present revealed that two medical radiographic procedures were commonly administered in 

connection with pre-employment, periodic, or post-employment medical examinations: the 14- by 17-

in. posterior-anterior (PA) chest films and the 14- by 17-in. lateral (LAT) chest films. 

Some of the claim file records have lumbar spinal exams that may also have been performed for 

screening (especially during pre-employment physicals) as opposed to injury. Organ doses for lumbar 

spinal exams can be found in ORAUT-OTIB-0006. 

In the early years at the site, periodic X-ray examinations were provided on an annual basis for 

workers who were required to wear respiratory protection, upon beginning employment, and on a 

two-year frequency after that (see Table 7-14). In the early years, individuals in at-risk groups could 

have received medical examinations including X-rays at various, perhaps even more frequent, 

intervals. Such workers can be identified from specific medical records. Other employees neither 

working with radiation nor required to wear respiratory protection could have had X-rays on a 

two-year frequency. The X-rays could have been both PA and LAT exposures for most workers when 

medical examinations were required (ORAUT-TKBS-0008-3). 

For NTS, waveform is of minor significance in relation to reconstruction of worker exposure because 

actual output measurement data are available from 1957 to 1992. Before 1957, machine techniques 

are not available and estimates of X-ray exposures are based on references providing median dose for 

1950 to 1957 (ORAUT-TKBS-0008-3, page 10). 

Available data, including direct beam measurements, indicate that X-ray beams used at NTS were 

well-collimated (ORAUT-TKBS-0008-3, page 11). 
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Table 7-14: Frequency of PA and LAT Chest X-rays at NTS 

Period Frequency Comment 

Entrance1,5 All employees 

Exit1 1951–1/1/1957 All employees 3

Biennial2, 5 For workers respirator qualified4

Entrance1 All employees6

Exit1 All employees6 1/1/1957–Present3

Biennial For workers respirator qualified4

Source: Adapted from ORAUT-TKBS-0008-3, page 14. 

Notes: 

1

Entrance and exit X-rays were provided from 1951 through January 1, 1957. These X-rays were not required after 1980 

unless personnel were in a job class that required an X-ray. 

2

Older workers above age 45 might have been required to have X-ray examinations. 

3

The LAT chest dose is not added to the overall worker dose unless there is a record of the examination in the worker’s 

file. 

4

 This exam included pulmonary function to determine lung capacity. 

5

Private contractors might have performed X-ray examinations offsite until the mid-1960s. 

6

Workers normally did not have LAT X-ray examinations and PA examinations might have been optional. 

Specific information on the calculation of dose from the two X-ray procedures used at NTS for dose 

reconstruction can be found in ORAUT-TKBS-0008-3. 

7.3.4 External Dose Reconstruction 

By April 2007, 1,471 EEOICPA claims from NTS workers had been submitted to NIOSH. Of those 

1,471 claims, 1,287 are for energy employees within the proposed class. Dose reconstructions have 

been completed for 900 of the 1,287 claims. 

There is an established protocol for assessing external exposure when performing dose reconstructions 

(these protocol steps are discussed in the following subsections): 

 Photon Dose 

 Electron Dose 

 Neutron Dose 

 Unmonitored Individuals Working in Production Areas 

 Medical X-ray 
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7.3.4.1 Photon Dose

Photon radiation dose reconstruction for NTS workers from 1963 through 1992 requires consideration 

of dosimeter response, photon field characteristics, and determination of any missed dose for 

monitored workers due to low dose (less than minimum detection level) results. NIOSH has sufficient 

information regarding the dosimetry used over the history of NTS operations to statistically account 

for dosimeter response considerations (bias and uncertainty), based on the dosimeter in use at the time 

of potential exposure (ORAUT-TKBS-0008-6). 

7.3.4.2 Electron Dose

In contrast to gamma rays and neutrons, beta rays have a finite range in matter determined by the 

energy of the beta particle. The maximum range associated with a beta produced by the decay of 

fission and activation products typically does not exceed approximately 36 feet. Therefore, an 

individual at a distance greater than 36 feet from a source of beta radiation would not receive an 

external dose from that beta radiation. Similarly, a person would receive no radiation dose to the skin 

from beta particles with energies less than 70 keV, because that is not sufficient energy to penetrate 

the dead, keratinized superficial layer of the epidermis (ORAUT-TKBS-0008-6, Section 6.3.5.2). 

In the event that personal dose records do not include estimates of beta dose, an estimate will be made 

from the associated photon (gamma + X-ray) exposure or dose equivalent using beta-photon ratios. 

Three common geometries associated with beta exposures are (1) standing on a contaminated surface, 

(2) immersion in contaminated clouds, or (3) exposure to discrete sources (ORAUT-TKBS-0008-6, 

page 46). 

External beta doses from standing on contaminated ground or other surfaces will be calculated by 

applying a beta-to-gamma dose ratio to an estimated upper-bound gamma dose, which is determined 

from film badge data or dose reconstruction (ORAUT-TKBS-0008-6, page 47). 

Immersion in a contaminated fallout debris cloud was a less likely circumstance than exposure to 

fallout after deposition on the ground or other surface given access controls employed by the site. 

However, exposure of workers to plumes of radioactive gas probably occurred following releases 

from underground tests. External beta doses from immersion in a contaminated cloud or plume can be 

calculated by applying a beta-to-gamma dose ratio to an estimated upper-bound gamma dose, which is 

determined from film badge data or dose reconstruction (ORAUT-TKBS-0008-6, page 47). 

If the potential exposure was likely due to discrete sources of beta-emitting nuclides, application of 

beta-photon ratios associated with such conditions can be used. The beta-photon ratio can be 

estimated from the radionuclide inventories known to be associated with a particular activity 

(ORAUT-TKBS-0008-6, page 48). 

More specific guidance is provided in ORAUT-TKBS-0008-6 on how to determine the best beta-tophoton ratio to be applied to estimate the beta dose from the relevant photon dose. Guidance is also 

provided using VARSKIN calculations to estimate dose to the skin resulting from contamination. 
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7.3.4.3 Neutron Dose

There is no indication that neutron-spectral measurements were conducted at NTS for radiation 

protection purposes. The spectra at NTS have been generally unmoderated and rich in fast neutrons; 

however, in some operational situations considerable scattering could have occurred, resulting in some 

softening. The International Atomic Energy Agency (IAEA) has compiled extensive neutron-spectral 

functions, instrument and dosimeter response functions, and dosimetric quantity response functions. 

Attachment A of ORAUT-TKBS-0008-6 presents additional detail regarding neutron-spectral 

characteristics. Because the source spectra for NTS operations are limited to those discussed in 

Section 5.3.3, adequate simulation can be obtained by selecting the proper neutron production 

mechanism and moderation and scatter conditions from the spectral catalogs that best simulate those 

for NTS operations. Guidance for the selection of parameters to determine the appropriate neutron 

characteristics is provided in ORAUT-TKBS-0008-6. 

If workers were unmonitored for fast neutrons, based on NTS personal dosimeter issue practices, and 

if there was no indication of exposure based on the thermal-neutron-sensitive component, it is highly 

unlikely that neutron exposure occurred. If a worker’s duties did not involve access to fissile 

materials or isotopic neutron sources, then neutron exposures or missed dose due to neutron will not 

be considered in dose reconstruction. Otherwise, for other-than-thermal neutrons, missed neutron 

doses will be assigned based on the number of indications of non-positive dosimetry cycle results 

found in the DOE records (ORAUT-TKBS-0008-6, page 52). 

7.3.4.4 Medical X-ray

There is no indication or suggestion in the data and documentation from the Medical X-ray program at 

NTS that the time or exposure parameters as documented in ORAUT-TKBS-0008-3 might be subject 

to error. Based on documentation and expert interviews, NIOSH believes chest photofluorography 

was not performed on the NTS workers. Chest photofluorography resulted in much greater doses than 

would a standard radiographic procedure. Determination of the occupational X-ray dose will be based 

on the documentation of frequency provided by DOE for the worker. If that documentation is 

insufficient to determine the frequency of X-ray examinations, the frequency indicated in Table 7-14 

would be considered conservative and used to determine the X-ray component of external dose. 

7.3.5 External Dose Reconstruction Feasibility Conclusion 

Based on the information presented in this section regarding available external exposure monitoring 

data, or the availability of data that support the ability to evaluate personnel external exposures, 

NIOSH has determined that it has access to extensive data for the members of the proposed worker 

class evaluated in this report, and has access to sufficient information to either: (1) estimate the 

maximum external 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 worker class; or 

(2) estimate the external radiation doses to members of the worker class more precisely than a 

maximum dose estimate. 
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7.4 Evaluation of Petition Basis for SEC-00084 

The following subsections evaluate the assertions made on behalf of petition SEC-00084 for NTS. 

Petition SEC-00084 originally cited all four of the bases as defined by the program, those being: (F.1) 

radiation exposures and radiation doses potentially incurred by members of the proposed class were 

not monitored; (F.2) radiation monitoring records for members of the proposed class have been lost, 

falsified, or destroyed; (F.3) a report from a health physicist or other individual with expertise in 

radiation dose reconstruction documenting the limitations of existing DOE or AWE records on 

radiation exposures at the facility; and (F.4) a scientific or technical report, issued by a government 

agency of the Executive Branch of Government or the General Accounting Office, the Nuclear 

Regulatory Commission , or the Defense Nuclear Facilities Safety Board, or published in a peerreviewed journal, that identifies dosimetry and related information unavailable for estimating the 

radiation doses of employees covered by the petition. Of these bases, both F.1 and F.3 were accepted 

by NIOSH as applicable to qualify the petition for evaluation. During the Qualification Review of the 

ten affidavits and fourteen supporting documents provided with the petition, NIOSH reviewed several 

affidavits asserting that the external monitoring program was circumvented by personnel deliberately 

removing their film badges in radiological control areas, which could potentially have led to 

unmonitored radiation exposure. Several reports included information on the limitations of existing 

DOE records were a part of the submission as support for basis F.3. 

Additionally, the petitioners indicated that the petition is based on unmonitored, unrecorded, or 

inadequately monitored and recorded exposure incidents. The petition identifies eight of the ten 

“unexpected releases of radioactivity” that are listed in ORAUT-TKBS-0008-6 as incidents. These 

eight were specifically identified as having occurred during the period addressed by this petition. 

While these releases were monitored, recorded, studied extensively, and are well-documented sources 

of exposure, they are specifically excluded from the scope of ORAUT-TKBS-0008-6. These events 

were not unmonitored, unrecorded, or inadequately monitored or recorded exposure incidents. These 

releases triggered significant attention from scientists and health physics personnel and are welldocumented in surveys, investigations, and subsequent reporting. These events have also been of 

interest to the epidemiological community observing the health effects associated with DOE facilities, 

which have been included in related studies and reports. Exposures due to these releases are reflected 

in personal dosimetry records and investigation reports. The exclusion of these releases from the 

scope of ORAUT-TKBS-0008-6 has no bearing on the EEOICPA radiological dose reconstruction. 

Any external dose resulting from these releases would be included in the assessment of total dose as 

ambient external dose. 
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7.4.1 Evaluation of Major Topics Detailed in Petition SEC-00084 

The following major topics were detailed in petition SEC-00084. Italicized statements are from the 

petition; the comments that follow are from NIOSH. 

7.4.1.1 Hot Particle Dose 

SEC-00084: Large hot-particle doses have not been evaluated. As a result, NIOSH is unable to 

adequately estimate external dose to gonads and skin, and internal dose to the gastrointestinal tract 

for many personnel, including early NRDS reentry personnel, early tunnel reentry personnel, and 

workers exposed to particles and gases from vented underground tests and drillback activity. This is 

a NTS complex-wide issue. 

Highly radioactive particles, also known as “hot particles” were produced by some NTS operations. 

Hot particle exposure is not easily identifiable from the records because it cannot be distinguished 

from the dosimeter response, and if it was not detected during the normal personnel survey, the 

particles would usually be removed by normal washing or changing of clothes. 

Indications of potential exposure to hot particles have been and must continue to be evaluated by 

NIOSH on a case-by-case basis. Significant potential for exposure to hot particles is limited to the 

immediate area surrounding the NRDS following reactor tests. Access to the reactor test areas was 

strictly controlled and documented. Hot particle deposition issues for this area (specific to cancers of 

the skin and shallow organs) will be addressed consistent with EEOICPA radiological dose 

reconstruction project guidance for assigning shallow dose in individual cases. 

Hot particle exposures associated with NRDS nuclear rocket re-entries are, as necessary, considered 

using the models and methods described in Hazards to Personnel Re-entering the Nevada Test Site 

Following Nuclear Reactor Tests, NRDL-TR-68-149 (NRDL, 1968). Supporting information relevant 

to the reactor test series and specific to an employee’s potential exposure history, as included in the 

employee’s work file from NTS, can be used in conjunction with the NRDL models and methods to 

develop a large particle GI tract or shallow dose (skin) assessment. All documentation, relevant to 

dose reconstruction, included in the worker file (e.g. notations in the whole-body count records) will 

be considered in the characterization of the reactor test scenario and the assessment of any potential 

large particle exposure to the organ(s) of interest. 

7.4.1.2 Defeating the Universal Badging Policy 

 

SEC-00084: It was common practice that workers, apparently at the direction of management, did not 

wear and/or hid dosimeter badges to prevent registering doses that would cause them to exceed 

project, monthly, or cumulative doses. Consequently, film badge data will underestimate the exposure 

of individuals and groups of workers. 
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There are indications that workers, and possibly groups of workers, did not wear assigned dosimeter 

badges at various times because they did not want to damage the badge and/or they were approaching 

the dose limit for the work period. NIOSH has documented interviews with former workers, former 

security personnel, health and safety personnel, and management staff to attempt to verify and 

evaluate this practice so as to ascertain its impact on the dosimetry records of the proposed class. 

These interviews were specifically tailored to determine the extent of noncompliance and focused on 

the job descriptions indicated by the affidavits provided in support of the petition. The interviews 

included specific questions about dosimetry noncompliance and were primarily conducted with 

former employees rather than with survivors, as former employees would have the most direct 

knowledge of the extent of this issue. Analysis of these interviews, as well as the Computer Assisted 

Telephone Interview records is depicted in Table 7-15. Table 7-15 indicates the percentage of 

interviewees that indicated that they purposely did not wear their dosimetry badge on the job (by job 

title). 

This analysis suggests that noncompliance with badging policies was not systematic or widespread as 

to affect the feasibility of dose reconstruction. When noncompliance with the badging policy is 

reported during the CATI or other claimant communication, NIOSH will apply reasonable dose 

estimations based on other records of exposure, such as log books or access log records with Pocket 

Ionization Chamber (a.k.a. PIC or pencil dosimeter) results. In addition, NIOSH has developed a 

methodology that incorporates the evaluation of an individual’s previous dose results in the estimation 

of dose for those individuals who may have been noncompliant with the badging policy because they 

believed they were reaching the upper limits of their allowable dose limit for the period. NIOSH has 

determined that this is a claimant issue rather than an SEC issue, such that issues relating to defeating 

the badging policy will have to be addressed on a case-by-case basis. 

Table 7-15: Results of Interviews regarding Defeat of the Universal Badging Policy 

Job Title No. of CATI 

Results 

Reviewed 

No. of 

Additional 

Interviews 

No. of Interviews by 

Job Category 

No. of Interviewees 

Indicating Monitoring 

Defeat 

Administrative 9 1 10 1 

Drill Worker/Engineer 32 1 33 3 

Tunnel Worker/Miner 66 1 67 1 

Plumber/Pipefitter 48 1 49 0 

Carpenter/Welder 36 0 36 1 

Surveyor/Civil Engineer 7 0 7 2 

Laborer 71 0 71 2 

Other 932 10 942 3 

Total 1,201 14 1,215 13 (1.1% of total ) 
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7.4.1.3 Resuspension 

SEC-00084: Resuspension models and factors are not scientifically defensible and a credible 

bounding dose estimate has not been developed. Doses may be underestimated by an order of 

magnitude due to the lack of data on “hot spots,” the failure to use a time dependent model, 

incomplete radionuclide lists, lack of adequate soil data for resuspension analysis/calculation, using 

data not appropriate for retrospective dose reconstruction, and using data collected in areas after 

“hot spots” were cleaned up to estimate doses prior to the cleanup. Due to these and numerous other 

uncertainties, NIOSH cannot develop a plausible upper bound dose estimate. 

The assertion by the petitioners that resuspension modeling and factors are inappropriate to determine 

dose from “hot spots” refers to an older proposed methodology for internal dose assignment using 

resuspension; the older methodology has been superseded by NIOSH. The greatest potential for 

environmental intakes of radioactive material results from inhalation of radioactive particles 

resuspended into the atmosphere and from ingestion of soils previously contaminated by atmospheric 

nuclear weapons tests and safety tests. The inhalation intakes of all potentially inhaled radionuclides 

will be estimated based on the highest recorded plutonium air sampling data provided in NTS Annual 

Environmental reports, in conjunction with extensive soil contamination data gathered between 1983 

and 1991. The air monitoring data were limited to gross alpha and beta measurements, tritium, and 

isotopes of plutonium; therefore, inhalation intakes of other relatively long-lived radionuclides 

identified in NTS soil are scaled to those of plutonium, based on their relative abundance in NTS soil. 

The relative abundances of the long-lived radionuclides identified in NTS soil contamination data 

have been decay-corrected to 1963. In addition, to ensure that intakes and resultant doses are not 

underestimated, correction factors have been developed to account for potential exposures to shortlived fission and activation products based on test-specific data. Further, a correction factor has been 

developed for inhalation intakes to account for the phenomenon of early resuspension. The NIOSH 

methodology is time-dependent and appropriate for retrospective dose reconstruction, and uses 

appropriate soil data. 

No documented radiological decontamination of “hot spots” took place between the end of 

atmospheric testing and the 1970s when air sampling data became more widely available. Interviews 

with former employees indicated that the areas previously used for atmospheric testing had been 

cleaned up, meaning that damaged structural materials, old vehicles, bridges, etc., that were subjected 

to close-range airbursts, were disposed of. These cleanup activities would not lower the radionuclide 

inventory available for worker internal exposure. 

7.4.1.4 Record Verification and Validation

SEC-00084: DOE records used by NIOSH have not been subject to verification and validationleading to errors. For instance, DOE claims to have dosimeter readings for workers when they were 

no longer employed at the site, and also claims that workers were no longer at the site when DOE or 

NIOSH documentation indicates that they were. 

NIOSH has performed a data validation review as part of this evaluation to confirm that the source 

data are representative and support the point that NIOSH can bound exposures (or reconstruct dose 

with sufficient accuracy) for members of the proposed worker class – please refer to Section 7.1.1 and 

7.1.2 of this report. In all reviewed cases, any alleged errors are clearly explained. The NTS 
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procedure of issuing dosimeters to visitors, including former workers returning to the site for tours, 

auctions, medical monitoring, etc., led to “readings” after the completion of the former worker’s 

employment. In some cases, the inclusion of internal dose—up to the diagnosis of cancer—in 

claimant records, including dose delivered beyond the completion of employment by radionuclides 

resident in their body, appears as a record error to individuals unfamiliar with dose reconstruction. 

The issues specific to individual claims and individual dose reconstruction analysis are handled on a 

case-by-case basis during the evaluation of the claim and do not represent an SEC issue and do not 

indicate a problem with NIOSH’s ability to bound the dose for the proposed worker class evaluated in 

this report. 

7.4.2 Evaluation of Specific Petitioner Statements in SEC-00084 

This subsection presents specific affidavit statements made on behalf of petition SEC-00084. The 

italicized statements are from the petition; the comments that follow are from NIOSH. 

7.4.2.1 Specific Affidavit Statement 1 

SEC-00084: NIOSH TBD-6 (External Dose) states that National Institute of Occupational Safety and 

Health (NIOSH) has no method to estimate dose for workers involved in eight underground tests that 

“vented” during the proposed class period (e.g., Baneberry, Camphor, Diagonal Line, Riola, Agrini, 

Midas Myth, Misty Rain, and Might Oak) as well as for those affected by drillbacks prior to 1965. As 

a result of this exemption, dose cannot be reconstructed for workers exposed in these eight events or 

the pre-1965 drillbacks. 

External dose associated with workers exposed to these ventings and drillbacks is captured similarly 

to all other external doses onsite, i.e., by the external dosimetry mechanisms employed over the 

history of the site. The primary focus of the radiation protection program at NTS was external 

dosimetry and all employees were monitored for external exposure. ORAUT-TKBS-0008-6 provides 

guidance on assigning appropriate external exposure.

7.4.2.2 Specific Affidavit Statement 2 

SEC-00084: Workers were scrupulous about keeping work related information confidential...making 

it impossible for survivors to provide the necessary information to enable NIOSH to adequately 

reconstruct dose. 

NIOSH acknowledges that survivors often do not have information regarding specific duties and 

responsibilities of their relatives who worked at NTS, as is the case for survivors for all other facilities 

in the U.S. Nuclear Weapons program. While, in accordance with the Privacy Act, there may not be 

published documentation of employee access records related to individual tests at the site, historic 

information and records have been made available to NIOSH by the site for the dose reconstruction 

process. 

The role of the EEOICPA radiological dose reconstruction program is to determine the probability of 

causation for individual workers (i.e., whether the cause of the worker’s cancer was at least as likely 

as not a result of occupational exposure to radiation), using claimant-favorable dose reconstruction 
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parameters, not to provide a precise regulatory compliance assessment of the worker dose. This 

permits the application of overestimating or underestimating dose reconstruction efficiency techniques 

in the performance of an EEOICPA radiological dose reconstruction. While information on all 

aspects of a worker’s job may not have been available to the claimants, that is no indication that the 

employee’s radiation dose cannot be bounded adequately to make a determination of causation. 

7.4.2.3 Specific Affidavit Statement 3 

SEC-00084: DOE has documented that the nuclear rocket and ramjet engine tests regularly released 

significant amounts of radionuclides that were detected hundreds of miles away, and therefore each 

test is a discreet incident. 

 

Discrete incidents, as defined by the EEOICPA program, are unplanned events that result in radiation 

exposures, which may be related to an unexpected failure in control procedures, likely to have 

involved exceptionally high-level exposures (comparable to those from a criticality incident), versus 

routine operations which might also result in radiation exposures. 

NIOSH has evaluated the releases associated with the nuclear rocket and ramjet engine tests and 

determined that they do not constitute discrete incidents, per this definition and guidance on health 

endangerment. The magnitude of the exposures is not commensurate with exposures as considered in 

the definition of “incident.” These exposures (tests) were not significantly higher than those 

experienced by other workers in the course of routine NTS operations. Detection of these releases at 

considerable distance from the releases is, in these cases, indicative of comprehensive attention and 

monitoring, highly sensitive detection equipment, and careful analysis; it is not indicative of the 

magnitude of the release or potential unmonitored exposure to the proposed class. 

7.4.2.4 Specific Affidavit Statement 4

SEC-00084: NIOSH lacks a method to estimate internal dose through 1967. 

Although NIOSH does have a method to estimate internal dose for this period, it has identified some 

deficiencies in the ability to bound the dose for the period as discussed in Section 7.2. 

7.4.2.5 Specific Affidavit Statement 5

SEC-00084: Whole body counts are unavailable until 1967, yet this data is used to extrapolate dose 

for workers who did different tasks in very different circumstances or only because of which area paid 

them. 

Whole-body counting was not generally introduced at any DOE sites until the late sixties and early 

seventies because the technology had not been sufficiently developed to provide reliable results. 

Internal monitoring was provided prior to 1967 by urinalysis. 

While whole-body counting results are not widely available for NTS claimants, there are adequate 

urinalysis data, which are used in conjunction with area monitoring and source term information to 

reconstruct internal dose for the determination of causation. NIOSH does not use employee wholebody counts to directly extrapolate dose for employees who had different job descriptions. Whole-
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body counts (from 1967 forward) are primarily useful to confirm dose reconstruction results, rather 

than a necessary component of the dose reconstruction. 

7.4.2.6 Specific Affidavit Statement 6 

SEC-00084: Exposure to radon is improperly estimated. There is no discussion of radon in Gravel 

Gerties, which could be substantial through 1985. 

The design of Gravel Gerties was tested at NTS in 1957 and 1982. Three tests were conducted in 

1957, two of which used uranium as a surrogate for plutonium and one that was conducted using high 

explosives without any radioactive materials at all. A fourth test of the design was conducted in 1982, 

again using uranium as a surrogate. These four tests used the same test structure, which was cleaned 

up and restored with new gravel for each subsequent test. 

The Gravel Gertie structure located in Area 5 was never used operationally, for the assembly and 

disassembly of weapons, at NTS. Radon exposure during construction would have been consistent 

with the environmental levels of radon found at NTS. Radon exposure, while setting-up the initial 

tests in this prototype design, would have been insignificant to the measured internal dose. If 

individual claim records indicate individual claimants spent significant amounts of time in the test 

Gravel Gerties, the radon exposure associated with those claims will be evaluated on a case-by-case 

basis, consistent with the guidance found in ORAUT-TKBS-0008-4. 

7.4.2.7 Specific Affidavit Statement 7 

SEC-00084: Radon doses for G-tunnel are not claimant favorable, and NIOSH’s proposal to use 

radon from the Pantex facility in Amarillo, Texas lacks a technical basis. 

NIOSH does not propose to use Pantex radon data to estimate radon exposures for the G-Tunnel. 

Based on comments from the Advisory Board and its contractor, the NTS Site Profile is currently 

undergoing revision to reflect an increased value of 0.16 working levels in the G-Tunnel for periods 

prior to 1985. The revised NTS Site Profile will instruct dose reconstructors, for cases where location 

of underground work is not known, to use the G-Tunnel value of 0.16 working level prior to 1985, and 

the value of 0.05 working level from 1985 forward. 

7.4.2.8 Specific Affidavit Statement 8 

SEC-00084: Although NTS workers were assigned to work on classified projects in locations such as 

Area 51, NIOSH has not assessed their radiation exposure or developed methods to do so in its site 

profile. 

NIOSH is not responsible for determining what is or is not covered employment at a facility. It is the 

responsibility of the Department of Labor (DOL) and DOE to define what is a covered facility and 

what constitutes covered employment. 
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7.4.2.9 Specific Affidavit Statement 9 

SEC-00084: Internal radiation exposure assessments rely on average air concentration values when 

the individual worker’s location is not known. If the work location is unknown, there is no basis for 

dose estimates. Averages for workers whose locations are known will not lead to a bounding dose 

estimate. 

NIOSH will always rely on available bioassay data as the primary record for internal dose 

reconstruction. In the absence of sufficient bioassay data for the individual, NIOSH will then rely on 

air concentration values, using the highest recorded plutonium air sample across NTS when a 

worker’s location is not known. The methodology to assess internal dose due to environmental 

exposures has been revised to determine internal dose based on air sampling data available for NTS. 

However, although NIOSH does have a method to estimate internal dose for the evaluated period at 

NTS, it has identified some deficiencies in the ability to bound the dose for the period, as discussed in 

Section 7.2. 

7.4.2.10 Specific Affidavit Statement 10 

SEC-00084: Many workers were unmonitored for iodine-131 exposures from 33 tests which vented 

approximately 1,065 kCi of iodine-131. NIOSH has no method to estimate unmonitored worker 

exposures. 

The ratios found in ORAUT-TKBS-0008-5, Table 5-2, and the highest concentration measured in 

Area 12 Camp after the Baneberry release have been used to develop a sample calculation that will be 

included in the NTS Internal Site Profile currently in the revision cycle. These sample calculation 

values can be used to determine iodine intake for an individual who may have been present during 

Baneberry. Similar calculations can be performed for other test releases using available air 

concentration data and when an iodine-131 intake is suspected based on the records available to 

NIOSH. However, although NIOSH does have a method to estimate internal dose for the evaluated 

period at NTS, it has identified some deficiencies in the ability to bound the dose for the period, as 

discussed in Section 7.2. 

7.4.2.11 Specific Affidavit Statement 11 

SEC-00084: The presence of high-fired oxides resulting from atmospheric weapons testing has not 

been investigated. High-fired plutonium oxides are less soluble than other oxides and, therefore, are 

retained in the lungs longer than other oxides and can take significantly longer to show up in a 

bioassay. These doses are not addressed in the TBD or dose assessments and it could take decades to 

construct an adequate dose model to estimate these exposures. 

Super S plutonium is addressed in ORAUT-OTIB-0049 and is evaluated at NTS starting in 1963. 

This issue is relevant to individual dose reconstruction analysis (on a case-by-case basis) and does not 

represent an SEC issue, as the comment or issue does not speak to NIOSH’s ability to bound the dose 

(or reconstruct the dose with sufficient accuracy) for the proposed class evaluated in this report. 
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7.4.2.12 Specific Affidavit Statement 12 

SEC-00084: There is no extremity dosimetry for bomb assembly workers. 

As discussed in Section 7.3.1.3 of this report, extremity dosimetry has been used at NTS to assess 

exposure to the finger, hand, forearms, and even the head (on rare occasions) that might have occurred 

during operations in proximity to, or the manual manipulation of, radioactive material and radiationemitting objects. 

The lack of extremity doses for some device assembly workers at NTS is surmountable. Extremity 

dose can be approximated using available dosimetry data in concert with geometrical correction 

factors and ratio correction techniques. Based on these techniques, this issue is not considered an 

SEC issue, but rather a site profile individual dose reconstruction issue.

7.4.2.13 Specific Affidavit Statement 13

SEC-00084: Workers report that monitoring and other records for NTS activities were lost or 

destroyed. 

A complete set of internal and external dosimetry records are maintained in the NTS archives located 

at the Desert Research Institute. During its interviews with workers, NIOSH specifically raised the 

question of lost or destroyed records. The responses indicated that the workers had heard claims of 

lost or destroyed records from the media outlets, but none had personal knowledge of any such 

records. One individual, a Former Workers Medical Surveillance Program employee who was also 

formerly a Records Manager at NTS, was able to specify the types of records reported in the media to 

have been buried. The records were administrative records, including timekeeping, mine rescue 

reports, access reports, log books, forms, injury reports, personnel rosters, and safety meeting records. 

The buried records did not, according to this interviewee, contain radiation protection or dosimetry 

records. Therefore, NIOSH has concluded that there is insufficient support for the claim that NTS 

monitoring records applicable to reconstructing personnel dose have been lost or destroyed. 

7.4.2.14 Specific Affidavit Statement 14 

SEC-00084: There was not an adequate internal dosimetry program in place from 1963 through 

1967. Full radionuclide coverage was not in place until 1967. Some tritium, plutonium, and mixed 

fission products were bioassayed prior to 1967. 

In addition to individual bioassay data, NTS internal dose reconstruction for the 1963 through 1967 

timeframe includes the use of ORAUT-OTIB-0018 and ORAUT-OTIB-0014 beginning in 1963. NTS 

routine bioassay programs, by activity, are documented in ORAUT-TKBS-0008-5 Attachment 5D.4.1. 

Workers were assigned to an activity-specific bioassay program (urine samples) based on having a 

high potential for intake. Each program was tailored to the conditions associated with the work; 

Workers may have been assigned to the bioassay program based on air monitoring, risk analysis of the 

activity, or other indications of potential internal exposure (e.g. personal contamination surveys). 

Although NIOSH does have a method to estimate internal dose for the evaluated period at NTS, it has 

identified some deficiencies in the ability to bound the dose for the period, as discussed in Section 7.2. 
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7.4.2.15 Specific Affidavit Statement 15 

SEC-00084: NIOSH erroneously reduces potential environmental doses for workers who remained 

continuously on site (lived on site), claiming without sufficient support that they spent most of their 

off-duty time indoors. This reduction should only be done if NIOSH can prove conclusively that 

workers indeed spent a large portion of their time indoors, and that they worked in building that were 

sealed, positively pressured, and/or were air conditioned, rather than in trailers, tents, or old 

buildings that relied on open windows and doors for cooling and ventilation, or that potentially 

drafted in air from the outside when the windows and doors were closed. 

While most applications of internal dose based on environmental concentrations assume a standard 

number of hours of occupational exposure, this can be adjusted, on a case-specific basis, to reflect 

more than 40 hours per week when documentation indicates the individual was living or staying onsite 

during the week. This issue is relevant to individual dose reconstruction analysis (on a case-by-case 

basis) and does not represent an SEC issue. However, although NIOSH does have a method to 

estimate environmental dose for the evaluated period at NTS, it has identified some deficiencies in the 

ability to bound occupational internal dose for the period, as discussed in Section 7.2. 

7.4.2.16 Specific Affidavit Statement 16 

SEC-00084: Moreover, it is documented that ambient monitoring using thermoluminescent dosimeters 

had failed. 

NIOSH does not rely on TLD measurements of environmental radiation conditions to determine 

ambient dose for dose reconstruction. Ambient dose, the dose due to non-occupational background 

radiation, was being measured and subtracted from the dose of record to account for strictly 

occupational dose before 1957. Ambient external dose is not assigned separately, during dose 

reconstruction, after 1957. The ambient external exposure is captured by the dosimetry badge worn 

universally at NTS. 

7.5 Other Issues Relevant to the Petition Identified During the Evaluation 

During the feasibility evaluation for SEC-00084, a number of issues were identified that needed 

further analysis and resolution. The issues and their current status include: 

 ISSUE: No external environmental measurements took place between 1968 and 1976. NIOSH 

proposes to use a maximum dose from 1967 as a surrogate. SC&A argues that extrapolating from 

1967 is inappropriate because there were no large unplanned vented tests that year. However, 

significant radionuclide deposits from vented tests from 1968 through 1970 may have caused 

external doses during that time period and several years after to be higher than doses in 1967. For 

example, of the ten large underground tests excluded from the NTS Site Profile, three of the 10 

occurred in the 1968 through 1976 time period (Baneberry, 1970; Camphor, 1971; and Diagonal 

Line, 1971.) 
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APPROACH: Unexposed control films and thermoluminescent dosimeters were processed with 

personnel dosimeters, and the readings from these control dosimeters were subtracted from the 

personnel dosimeter readings to obtain a net reading for determining worker exposure. Beginning 

on April 1, 1957, all employees entering NTS were required to wear dosimeters while inside NTS. 

Because the control dosimeters were maintained in environmentally controlled, low background 

areas (e.g., Building 111 in Mercury), exposures resulting from elevated ambient environmental 

levels due to testing activities in other areas of the site would have been recorded by the 

dosimeters and included in the individual exposure records. The assignment of ambient external 

dose will be applied consistent with ORAUT-PROC-0060, Occupational Onsite Ambient Dose 

Reconstruction for DOE Sites. 

 ISSUE: Bioassay performed every few months would not detect the presence of relatively shortlived radionuclides, such as sodium-24 and neptunium-239. Workers entering contaminated areas 

within days of a test that vented may have been exposed to a variety of short-lived radionuclides. 

The TBD does not specify a procedure for evaluating exposures to such radionuclides for 

monitored workers. 

APPROACH: Data contained in the Hicks reports confirm that neptunium-239 was not a 

significant contributor to dose at NTS. The relative importance of sodium-24 to total internal dose 

during reentry activities occurring in the first week after the event is understood; guidance to 

adjust dose due to sodium-24, as appropriate, has been documented in a draft methodology that 

will be incorporated in the revised NTS Site Profile that is currently in the revision cycle. NIOSH 

defines missed intakes as those which could have been incurred at levels less than the minimum 

detectable activity for bioassay. 

 ISSUE: Use of 1967 external dose data for 1963-1966 is not claimant-favorable. There was no 

test in 1967 with measurable offsite fallout. Relatively short-lived radionuclides, which were 

likely present in 1963-1966, would have substantially decayed away by 1967. 

APPROACH: Ambient external dose is not assigned to monitored individuals. The ambient 

external exposure is captured by the dosimetry badge worn universally at NTS. This issue is 

relevant to individual dose reconstruction analysis (on a case-by-case basis) and does not represent 

an SEC issue because the comment or issue does not speak to NIOSH’s ability to bound the dose 

(or reconstruct the dose with sufficient accuracy) for the proposed class evaluated in this report. 
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7.6 Summary of Feasibility Findings for Petition SEC-00084 

This report evaluates the feasibility for completing dose reconstructions for NTS employees from 

January 1, 1963 through December 31, 1992. NIOSH found that the available monitoring records, 

process descriptions and source term data available are insufficient to complete dose reconstructions 

for the proposed class of employees. 

Table 7-16 summarizes the results of the feasibility findings at NTS for each exposure source during 

the time period from January 1, 1963 through December 31, 1992. 

Table 7-16: Summary of Feasibility Findings for SEC-00084 

(January 1963 through December 1992) 

Source of Exposure Reconstruction Feasible Reconstruction Not Feasible 

Internal X 

 - Uranium X 

 - Plutonium X 

 - Gross Fission Products X 

External X 

 - Gamma X 

 - Beta X 

 - Neutron X 

 - Occupational Medical X-ray X 

8.0 Evaluation of Health Endangerment for Petition SEC-00084 

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

governed by both EEOICPA and 42 C.F.R. § 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 determine that there is a reasonable likelihood that such radiation doses may have endangered the 

health of members of the class. Section 83.13 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. 
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Upon review of NTS monitoring data deficiencies, NIOSH’s evaluation determined that it is not 

feasible to estimate radiation dose for members of the NIOSH-evaluated class with sufficient accuracy 

based on the sum of information available from available resources. Modification of the class 

definition regarding health endangerment and minimum required employment periods, therefore, is 

required. 

9.0 NIOSH-Proposed Class for Petition SEC-00084 

Based on its full research of the class under evaluation, NIOSH has defined a single class of 

employees for which NIOSH cannot estimate radiation doses with sufficient accuracy. The 

NIOSH-proposed class to be added to the SEC includes all employees of the Department of Energy, 

its predecessor agencies, and its contractors and subcontractors who worked at the Nevada Test Site, 

from January 1, 1963 through December 31, 1992, 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 established for one or more other classes of employees in the SEC. The class has been 

proposed for addition to the SEC because the feasibility of reconstructing doses associated with 

potential internal exposures may be directly impacted by data gaps for certain radionuclides over the 

span of operations, and the actual exposure risk associated with various exposure scenarios. 

NIOSH has established that it has access to sufficient information to: (1) estimate the maximum 

radiation dose incurred by any member of the class; or (2) estimate radiation doses more precisely 

than a maximum dose estimate for the period from January 1, 1993 forward. Information available 

from the Site Profile and additional resources is sufficient to document or estimate the maximum 

internal and external potential exposure to members of the proposed class under plausible 

circumstances during this period. 

NIOSH has carefully reviewed all material sent in by the petitioner, including the specific assertions 

stated in the petition, and has responded herein (see Section 7.4). NIOSH has also reviewed available 

technical resources and many other references, including the Site Research Database (SRDB), for 

information relevant to SEC-00084. In addition, NIOSH reviewed its NOCTS dose reconstruction 

database to identify EEOICPA-related dose reconstructions that might provide information relevant to 

the petition evaluation. 

These actions are based on existing, approved NIOSH processes used in dose reconstruction for 

claims under EEOICPA. NIOSH’s guiding principle in conducting these dose reconstructions is to 

ensure that the assumptions used are fair, consistent, and well-grounded in the best available science. 

Simultaneously, uncertainties in the science and data must be handled to the advantage, rather than to 

the detriment, of petitioners. When adequate personal dose monitoring information is not available, or 

is very limited, NIOSH may use the highest reasonably possible radiation dose, based on reliable 

science, documented experience, and relevant data to determine the feasibility of reconstructing the 

dose of an SEC petition class. NIOSH contends that it has complied with these standards of 

performance in determining that it would be feasible to reconstruct the dose for the class proposed in 

this petition. 
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10.0 References 

42 C.F.R. pt. 81, Guidelines for Determining the Probability of Causation Under the Energy 

Employees Occupational Illness Compensation Program Act of 2000; Final Rule, Federal 

Register/Vol. 67, No. 85/Thursday, p 22,296; May 2, 2002; SRDB Ref ID: 19391 

42 C.F.R. pt. 82, Methods for Radiation Dose Reconstruction Under the Energy Employees 

Occupational Illness Compensation Program Act of 2000; Final Rule; May 2, 2002; SRDB Ref ID: 

19392 

42 C.F.R. pt. 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; Final Rule; May 28, 2004; SRDB Ref ID: 22001 

42 U.S.C. §§ 7384-7385 [EEOICPA], Energy Employees Occupational Illness Compensation 

Program Act of 2000, as amended; OCAS website 

Affidavit, 2006, Affidavit from Former Foreman/Pipe-fitter/Welder, Attachment 6; January 10, 2006; 

OSA Ref ID: 102557 

Affidavit, 2007a, Affidavit from Former Laborer/Labor Foreman, Attachment 4; January 10, 2007; 

OSA Ref ID: 102555 

Affidavit, 2007b, Affidavit from Former Driller/Drill Supervisor/Project Manager of Drilling, 

Attachment 5; January 17, 2007; OSA Ref ID: 102556 

Affidavit, 2007c, Affidavit from Former Union President, Attachment 7; January 29, 2007; OSA Ref 

ID: 102558 

Affidavit, 2007d, Affidavit from Survivor, Attachment 10; January 18, 2007; OSA Ref ID: 102541 

Affidavit, 2007e, Affidavit from Former Carpenter’s Apprentice/Carpenter/Welder, Attachment 11; 

January 31, 2007; OSA Ref ID: 102542 

Affidavit, 2007f, Affidavit from Former Driller, Attachment 12; January 31, 2007; OSA Ref ID: 

102543 

Affidavit, 2007g, Affidavit from Survivor, Attachment 13; January 26, 2007; OSA Ref ID: 102544 

Affidavit, 2007h, Affidavit from Survivor, Attachment 14; January 30, 2007; OSA Ref ID: 102561 

Affidavit, 2007i, Affidavit from Former Welder, Attachment 15; January 31, 2007; OSA Ref ID: 

102792 

AIHA, 1963, Respiratory Protective Devices Manual; American Industrial Hygiene Association 

(AIHA); 1963; SRDB Ref ID: 7963 
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Allen, 1993, Technical Basis for Internal Dosimetry at the Nevada Test Site, DOE/NV/10630-64; T. 

E. Allen, E. Zervoudis, C. T. Bastian, and H. F. Kerschner, Reynolds Electrical and Engineering 

Company, Incorporated; June 30, 1993; SRDB Ref ID: 1948 

Allen, 1995, External Dosimetry Technical Basis Manual for the Nevada Test Site and Other 

Designated Locations; T. E. Allen and C. R. Schoengold; Reynolds Electrical and Engineering 

Company, Inc.; December 1995; SRDB Ref ID: 14099 

Anspaugh, 1996, Technical Basis for Dose Reconstruction, Attachment 18, Lynn Anspaugh; January 

31, 1996; OSA Ref ID: 102547

Anspaugh, 1997, Introduction to Section II and Overview of Dose Reconstruction; Lessons Learned 

from Studies in the U.S., Attachment 19, Lynn R. Anspaugh; January 1997; OSA Ref ID: 102548 

Anspaugh, 2002, Movement of Radionuclides in Terrestrial Ecosystems by Physical Processes, 

Attachment 17; Lynn Anspaugh, Steven Simon, Gordeev Konstantin, Ilya likhtarey, Reed Maxwell, 

and Sergei Shinkarev, Health Physics Vol 82, No. 5; May 2002; OSA Ref ID: 102546 

Anspaugh, 2006, The Resuspension Pathway for Nevada Test Site Workers, Rev. 03, Attachment 9, 

Lynn Anspaugh, SC&A; October 8, 2006; OSA Ref ID: 102560 

Arent, 2004, Record of Interview with [Name Redacted], Bechtel Nevada; Lori Arent and Cheryl 

Smith; August 18, 2004; SRDB Ref ID: 14054 

Bechtel Nevada, 2002, Nevada Test Site Annual Site Environmental Report for Calendar Year 2001, 

DOE/NV/11718-747; Bechtel Nevada; October 2002; SRDB Ref ID: 1810 

Bechtel Nevada, 2003, Technical Basis for Internal Dosimetry at the Nevada Test Site, Revision 5, 

TBD-E211-002; Bechtel Nevada, Inc.; April 2003; SRDB Ref ID: 7821 

Biles, 1973, AEC/LASL Respirator Protection Training Program; Martin B. Biles; February 1973; 

SRDB Ref ID: 16620 

Black, 1995, National Emission Standards for Hazardous Air Pollutants Submittal-1994, 

DOE/NV/11432-194/UC-600; Stuart C. Black, Reynolds Electrical and Engineering Co., Inc.; 

June1995; SRDB Ref ID: 8071 

Boice, 2006, A Comprehensive Dose Reconstruction Methodology for Former Rocketdyne/Atomics 

International Radiation Workers, Attachment 20, John Boice, Richard Leggett, Elizabeth Ellis, Phillip 

Wallace, Michael Mumma, Sarah Cohen, Bertrand Brill, Bandana Chadda, Bruce Boecker, Craig 

Yoder, and Keith Eckerman, Health Physics Vol. 90, No. 5; May 2006; OSA Ref ID: 102549

Boone, 1970, Progress Report, NRDB Personnel Dosimetry Program, Statistical Comparison of TLD 

and Film Dosimeter Data, Report No: 33-37; F. W. Boone and S. B. Adams; July 24, 1970; SRDB 

Ref ID: 13988 

Brown, no date, Reentry Problems Associated with Radiation from Underground Nuclear 

Detonations, RRS-63-10; B. L. Brown; no date; SRDB Ref ID: 8054 
SEC-00084 01-25-10 Rev.1 FINAL Nevada Test Site (NTS)

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DOE, 1988, Radiation Protection for Occupational Workers, DOE 5480.11; U.S. Department of 

Energy (DOE); December 21, 1988; SRDB Ref ID: 8073 

DOE, 1992, Radiological Control Manual, DOE/EH-0256T; Department of Energy; June 1992; 

SRDB Ref ID: 11515 

Dummer, 1958, Los Alamos Handbook of Radiation Monitoring, 3rd Edition; Jerome E. Dummer, Jr., 

Los Alamos Scientific Laboratory; November 1958; SRDB Ref ID: 16881 

Fauver, 1987, Survey of Radon and Radon Daughter Concentrations in Selected Rainier Mesa 

Tunnels, DOE/NV/10327-31, David N. Fauver; January 1987; SRDB Ref ID: 7851 

French, 1995, Evaluation of Protection, Bioassay, and Dose Assessment Programs for Internal 

Radiation Exposures at the Nevada Test Site Particularly as Related to Three Exposure Situations; 

Clayton S. French and Kenneth W. Skrable; September 30, 1995; SRDB Ref ID: 14050 

Geiger, 1961, Analytical Procedures of the Radiological Safety Laboratory, Nevada Test Site, RRS61-5; E. L. Geiger and E. L. Whittaker; April 1961; SRDB Ref ID: 2103 

Hendricks, 2006; Email Correspondence Regarding SC&A Findings on the NTS Site Profile, 

Attachment 8; Don Hendricks; February 23, 2006; OSA Ref ID: 102559

Hicks, 1981a, Results of Calculations of External Gamma Radiation Exposure Rates from Fallout and 

the Related Radionuclide Compositions: Operation Buster-Jangle 1951, UCRL-53152 Pt. 2, Harry G. 

Hicks; July 1981; SRDB Ref ID: 1831 

Hicks, 1981b, Results of Calculations of External Gamma Radiation Exposure Rates from Fallout and 

the Related Radionuclide Compositions: Operation Teapot 1955, UCRL-53152 Pt. 5, Harry G. Hicks; 

July 1981; SRDB Ref ID: 1838 

Hicks, 1981c, Results of Calculations of External Gamma Radiation Exposure Rates from Fallout and 

the Related Radionuclide Compositions: Operations Nougat through Bowline 1962-1968, UCRL53152 Pt. 8, Harry G. Hicks; July 1981; SRDB Ref ID: 1851 

Hicks, 1981d, Results of Calculations of External Gamma Radiation Exposure Rates from Fallout and 

the Related Radionuclide Compositions: Operation Ranger 1951, UCRL-53152 Pt. 1, Harry G. Hicks; 

July 1981; SRDB Ref ID: 1854 

IAEA, 1967, Respirators and Protective Clothing; International Atomic Energy Agency (IAEA); 

1967; SRDB Ref ID: 16559 

Kimmel, 1963, Dynamic Environmental Sampling Program, Information Bulletin #92; James D. 

Kimmel; June 12, 1963; SRDB Ref ID: 8019 

Kinnison, 1997, Environmental Data Report for the Nevada Test Site-1995, DOE/NV/11718-038; 

Robert R. Kinnison; October 1997; SRDB Ref ID: 1793 
SEC-00084 01-25-10 Rev.1 FINAL Nevada Test Site (NTS)

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LASL, 1954, Analytical Procedures of the Industrial Hygiene Group, LA-1858; Los Alamos 

Scientific Laboratory (LASL); December 1954; SRDB Ref ID: 13981 

Layton, 1993, Risk Assessment of Soil-Based Exposures to Plutonium at Experimental Sites Located 

on the Nevada Test Site and Adjoining Areas, Attachment 21; David Layton, Lynn Anspaugh, 

Kenneth Bogen, and Tore Straume; June 1993; OSA Ref ID: 102550 

Lewis, 1965, Environmental Radioactivity at the Nevada Test Site, July 1964 through June 1965, 

NVO-162-18; Gary B. Lewis, Michael A. Glora, and Isamu Aoki; December 1965; SRDB Ref ID: 

1681 

LRL, 1961, General Re-Entry Procedure for Underground Nuclear Events, CN-294; Lawrence 

Radiation Laboratory (LRL); November 9, 1961; SRDB Ref ID: 8038 

Lyons, September 1992, Operational Air Sampling Report - January 1 through June 30, 1992, 

DOE/NV/10630-42; C. L. Lyons; September 1992; SRDB Ref ID: 8575 

Lyons, November 1992, Operational Air Sampling Report - July through December 1991, 

DOE/NV/10630-37; C. L. Lyons; November 1992; SRDB Ref ID: 8583 

Marsh, 1983, Evaluation of Irritant Smoke Qualitative Fitting Test for Respirators, LA-9778-MS; 

James L. Marsh; August 1983; SRDB Ref ID: 16558 

Martell, 1964, Iodine-131 Fallout from Underground Tests, Attachment 22, E. A. Martell, Science

Vol. 143, No. 3602; January 10, 1964; OSA Ref ID: 102551 

McArthur, 1983, Radionuclide Inventory and Distribution Program: The Galileo Area, 

DOE/NV/10162-14; Richard D. McArthur and Joseph F. Kordas; December 28, 1983; SRDB Ref ID: 

7868 

McArthur, 1985, Radionuclide Inventory and Distribution Program: Report #2. Areas 2 and 4, 

DOE/NV/10162-20, Richard D. McArthur and Joseph F. Kordas; September 1985; SRDB Ref ID: 

7856 

McArthur, 1987, Radionuclide Inventory and Distribution Program: Report #3. Areas 3, 7, 8, 9, and 

10, DOE/NV/10384-15; Richard D. McArthur and S. Warren Mead; February 1987; SRDB Ref ID: 

7860 

McArthur, 1988, Radionuclide Inventory and Distribution Program: Report #4. Areas 18 and 19, 

DOE/NV/10384-22; Richard D. McArthur and S. Warren Mead; April 1988; SRDB Ref ID: 7854 

McArthur, 1989, Nevada Test Site Radionuclide Inventory and Distribution Program: Report #5. 

Areas 5, 11, 12, 15, 17, 18, 19, 25, 26, and 30, DOE/NV/10384-26; Richard D. McArthur and S. 

Warren Mead; June 1989; SRDB Ref ID: 7865 

McArthur, 1991, Radionuclides in Surface Soil at the Nevada Test Site, DOE/NV/10845-02, 

Attachment 23; Richard McArthur; August 1991; OSA Ref ID: 102552 
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McMahon, 2003, Technical Basis for Internal Dosimetry at the Nevada Test Site, TBD-E211-002; M. 

McMahon and A. G. Ogurek; April 2003; SRDB Ref ID: 7821 

Morgan, 1953, Air Contamination and Respiratory Protection in Radioisotope Work, AECU-2821; G. 

W. Morgan and C. R. Buchanan; January 19, 1953; SRDB Ref ID: 16557 

NIOSH, 2007, SEC Petition Evaluation Report for Petition SEC-00084, Nevada Test Site; Rev. 0; 

National Institute for Occupational Safety and Health (NIOSH); September 25, 2007; SRDB Ref ID: 

77699 

NRDL, 1968, Hazards to Personnel Re-entering the Nevada Test Site Following Nuclear Reactor 

Tests, NRDL-TR-68-149; Naval Radiological Defense Laboratory (NRDL); December 1968; SRDB 

Ref ID: 8033 

NTS, no date, Section 14—Dosimetry, procedure; Nevada Test Site (NTS); no date; SRDB Ref ID: 

1989 

NTS, 1968, Section 29—Personnel Dosimetry and Records, procedure; Nevada Test Site (NTS); 

1968; SRDB Ref ID: 2007 

NTS, 1978, Section L5—Personnel Dosimetry and Records, procedure; Nevada Test Site (NTS); 

1978; SRDB Ref ID: 2021 

NTS, 1993, Technical Basis for Internal Dosimetry at the Nevada Test Site, Reynolds Electrical and 

Engineering Co., Inc.; DOE/NV/10630-64; June 30, 1993; SRDB Ref ID: 1948 

NTS Bioassay Data, 2009, Electronic files containing bioassay data for the Nevada Test Site for the 

years 1955-2000; provided to NIOSH by Nevada Test Site on August 19, 2009; SRDB Ref ID: 73342 

OCAS-IG-001, External Dose Reconstruction Implementation Guideline, Rev. 02; Office of 

Compensation Analysis and Support (OCAS); August 25, 2006; SRDB Ref ID: 29929 

OCAS-IG-002, Internal Dose Reconstruction Implementation Guideline; Office of Compensation 

Analysis and Support (OCAS); August, 2002; SRDB Ref ID: 22402 

OCAS-TIB-0011, Lung Dose Conversion Factor for Thoron WLM, Rev. 02; Office of Compensation 

Analysis and Support (OCAS); January 13, 2006; SRDB Ref ID: 22409 

ORAUT-OTIB-0002, Maximum Internal Dose Estimates for Certain DOE Complex Claims, Rev. 02; 

Oak Ridge Associated Universities (ORAU); February 7, 2007; SRDB Ref ID: 29947 

ORAUT-OTIB-0006, Dose Reconstruction from Occupationally Related Diagnostic X-Ray 

Procedures, Rev. 03 PC-1; Oak Ridge Associated Universities (ORAU); December 21, 2005; SRDB 

Ref ID: 20220 

ORAUT-OTIB-0011, Tritium Calculated and Missed Dose Estimates, Rev. 00; Oak Ridge Associated 

Universities (ORAU); June 29, 2004; SRDB Ref ID: 19430 
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ORAUT-OTIB-0014, Assignment of Environmental Internal Doses for Employees Not Exposed to 

Airborne Radionuclides in the Workplace, Rev. 00; Oak Ridge Associated Universities (ORAU); June 

22, 2004; SRDB Ref ID: 19432 

ORAUT-OTIB-0017, Interpretation of Dosimetry Data for Assignment of Shallow Dose, Rev. 01; 

Oak Ridge Associated Universities (ORAU); October 11, 2005; SRDB Ref ID: 19434 

ORAUT-OTIB-0018, Internal Dose Overestimates for Facilities with Air Sampling Programs, Rev. 

01; Oak Ridge Associated Universities (ORAU); August 09, 2005; SRDB Ref ID: 19436 

ORAUT-OTIB-0049, Estimating Doses for Plutonium Strongly Retained in the Lung, Rev. 00; Oak 

Ridge Associated Universities (ORAU); February 6, 2007; SRDB Ref ID: 29975 

ORAUT-PROC-0060, Occupational Onsite Ambient Dose Reconstruction for DOE Sites, Rev. 01; 

Oak Ridge Associated Universities (ORAU); June 28, 2006; SRDB Ref ID: 29986 

ORAUT-PROC-0061, Occupational X-Ray Dose Reconstruction for DOE Sites, Rev. 01; Oak Ridge 

Associated Universities (ORAU); July 21, 2006; SRDB Ref ID: 29987

ORAUT-TKBS-0008-1, Nevada Test Site—Introduction, Rev. 00 PC-1; Oak Ridge Associated 

Universities (ORAU); July 20, 2006; SRDB Ref ID: 29994 

ORAUT-TKBS-0008-2, Nevada Test Site—Site Description, Rev. 00; Oak Ridge Associated 

Universities (ORAU); February 2, 2004; SRDB Ref ID: 19793 

ORAUT-TKBS-0008-3, Nevada Test Site—Occupational Medical Dose, Rev. 01; Oak Ridge 

Associated Universities (ORAU); June 22, 2007; SRDB Ref ID: 19794 

ORAUT-TKBS-0008-4, Nevada Test Site—Occupational Environmental Dose, Rev. 00 PC-1; Oak 

Ridge Associated Universities (ORAU); December 8, 2006; SRDB Ref ID: 29995 

ORAUT-TKBS-0008-5, Nevada Test Site—Occupational Internal Dose, Rev. 00 PC-1; Oak Ridge 

Associated Universities (ORAU); July 20, 2006; SRDB Ref ID: 29996 

ORAUT-TKBS-0008-6, Nevada Test Site—Occupational External Dose, Rev. 01; Oak Ridge 

Associated Universities (ORAU); July 30, 2007; SRDB Ref ID: 34013 

ORAUT-TKBS-0035-5, Lawrence Livermore National Laboratory—Occupational Internal Dose, 

Rev. 01 C; Oak Ridge Associated Universities (ORAU); July 9, 2007; SRDB Ref ID: not currently 

assigned 

OTA, 1989, The Containment of Underground Nuclear Explosions, OTA-ISC-414; Office of 

Technology Assessment (OTA); October 1989; SRDB Ref ID: 8029 

Personal Communication, 2005, Personal Communication with [Names Redacted]; Interviewed by 

SC&A; July 22, 2005; SRDB Ref ID: 34581 
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Personal Communication, 2007a, Personal Communication with a Security Officer; Telephone 

Interview by B. Murray and C. Miles; 1100 EDT July 16, 2007 SRDB Ref ID: 34046 

Personal Communication, 2007b, Personal Communication with a Tunnel Miner/Core Driller; 

Telephone Interview by B. Murray and C. Miles; 1430 EDT July 16, 2007 SRDB Ref ID: 34051

Personal Communication, 2007c, Personal Communication with a former records 

manager/administrative/clerical supervisor for underground tests; Telephone Interview by B. Murray 

and C. Miles; 1300 EDT July 18, 2007 SRDB Ref ID: 34049

Personal Communication, 2007d, Personal Communication with the survivor of a Nuclear Rocket 

Development Station employee; Telephone Interview by B. Murray and C. Miles; 1200 EDT July 18, 

2007 SRDB Ref ID: 34052 

Personal Communication, 2007e, Personal Communication with a construction support employee; 

Telephone Interview by B. Murray and C. Miles; 1400 EDT July 18, 2007 SRDB Ref ID: 34047

Personal Communication, 2007f, Personal Communication with two survivors; Telephone Interview 

by B. Murray and C. Miles; 1600 EDT July 18, 2007 SRDB Ref ID: 34035 

Personal Communication, 2007g, Personal Communication with a custodial employee/shaft miner; 

Telephone Interview by B. Murray and C. Miles; 1130 EDT July 19, 2007; SRDB Ref ID: 34038 

Personal Communication, 2007h, Personal Communication with a plumber/pipefitter; Telephone 

Interview by B. Murray and C. Miles; 1200 EDT July 23, 2007; SRDB Ref ID: 34034

Personal Communication, 2007i, Personal Communication with a Security Officer; Telephone 

Interview by B. Murray and C. Miles; 1330 EDT July 23, 2007; SRDB Ref ID: 34037

Personal Communication, 2007j, Personal Communication with an AEC Health Physicist; email 

correspondence to B. Murray and C. Miles; July 25, 2007; SRDB Ref ID: 34036 

Personal Communication, 2007k, Personal Communication with a Health Physicist; Telephone 

Interview by B. Murray and C. Miles; 1100 EDT July 25, 2007; SRDB Ref ID: 34039

Personal Communication, 2007l, Personal Communication with a Health Physicist; Telephone 

Interview by B. Murray and C. Miles; 1230 EDT July 25, 2007; SRDB Ref ID: 34044 

Personal Communication, 2007m, Personal Communication with a Radiological Control Technician; 

Telephone Interview by B. Murray and C. Miles; 1400 EDT August 06, 2007; SRDB Ref ID: 34064 

Personal Communication, 2007n, Personal Communication with an Operating Engineer; Telephone 

Interview by B. Murray and C. Miles; 0900 EDT August 10, 2007; SRDB Ref ID: 34065 

REECo, date unknown, Project 400 MAD Building Standard Operating Procedures; Reynolds 

Electrical & Engineering Company, Inc. (REECo); date unknown; SRDB Ref ID: 8041
SEC-00084 01-25-10 Rev.1 FINAL Nevada Test Site (NTS)

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REECo, 1958, Operation Hardtack Phase II On-Site Rad-Safe Report, OTO 58-5, Reynolds Electrical 

and Engineering Company (REECo); 1958; SRDB Ref ID: 2503

REECo, 1959, Operational Guides for Above-Ground Drill Sites into Ground Zero Areas, 

Information Bulletin #24, Reynolds Electrical and Engineering Company (REECo); November 13, 

1959; SRDB Ref ID: 7832

REECo, 1961, Standard Operating Procedures for the Radiological Safety Division; Reynolds 

Electrical and Engineering Company, Inc. (REECo); January 1961; SRDB Ref ID: 8044

REECo, 1964, Operation Storax On-Site Radiological Safety Report, NVO-162-14; Reynolds 

Electrical & Engineering Company, Inc. (REECo); September 1964; SRDB Ref ID: 16657 

REECo, 1991, Operational Dosimetry Branch Standard Operating Procedures; Reynolds Electrical 

and Engineering Co., Inc.(REECo); September 27, 1991; SRDB Ref ID: 2060

Reeves, 1962, Procedures to Limit Radiation Exposure of Miners at NTS, memorandum to A. R. 

Leudecke from James Reeves; James E. Reeves; April 20, 1962; SRDB Ref ID: 8042

Rodgers, no date, Performance Evaluation of LANL Environmental Radiological Air Monitoring 

Inlets at High Wind Velocities Associated with Resuspension, Attachment 24, John Rodgers, Piotr 

Wasiolek, Jeff Whicker, Craig Eberhart, Keith Saxton, and David Chandler; no date; OSA Ref ID: 

102553 

Rogers, 2006, Test Site Workers’ Records Dumped, Attachment 16; Keith Rogers, Las Vegas ReviewJournal (Nevada); September 25, 2006; OSA Ref ID: 102545 

Rollins, 2007, Ambient Environmental Intakes at the Nevada Test Site Based on Air Sampling and Soil 

Contamination Data, July 5, 2007, Draft, E. M. Rollins; 2007, SRDB Ref ID: not currently assigned 

SCA-TR-TASK1-0006, NIOSH Responses to SC&A Comments: Draft Review of the NIOSH Site 

Profile for the Nevada Test Site, SCA-TR-TASK1-0006, Attachment 2; December 31, 2005; OSA Ref 

ID: 102554

Scoggins, 1983, Environmental Surveillance Report for the Nevada Test Site (January 1982 through 

December 1982), DOE/NV/00410-78; Wayne A. Scoggins; June 1993; SRDB Ref ID: 1740 

Smith, 2007, Email Regarding the Verification of Dosimetry Records, email correspondence; Cheryl 

Smith; August 10-21, 2007; SRDB Ref ID: 34588 

Teasdale, 1985, Whole Body Counting Facility, Nevada Test Site; Cathryn Teasdale; November 1985; 

SRDB Ref ID: 14045 

University of California, 1965, Palanquin, Reentry and Recovery Safety Procedure; University of 

California and Lawrence Radiation Laboratory; 1965; SRDB Ref ID: 8037 
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Unknown author, 1951-1973, NTS General Information, 1951-1973, list by year of instruments, 

dosimetry, rad levels, exposure criteria, respiratory protection, and calibration information; Unknown 

author; 1951-1973; SRDB Ref ID: 2614 

Various authors, Various dates, Nevada Test Site—Review of Medical Surveillance, Summary of 

Radiation Exposure Date Analyses, Summary of Worker Demographics and Work History 

Information on Radiation Hazards, Attachment 1, various documents; Uploaded on February 6, 2007; 

OSA Ref ID: 102540 

Wilcox, 1958, Electronic Data Processing as Applied to Personnel Radiation Dosimetry, RRS-58-2; 

F. W. Wilcox and G. L. Jacks; May 21, 1958; SRDB Ref ID: 1982

Wilcox, 1960, Radiological Safety for Underground Nuclear Explosions, RRS-60-3; Floyd W. Wilcox 

and John S. Coogan; June 9, 1960; SRDB Ref ID: 8043

Wilcox, 1961, Information Bulletin #63, correspondence to Division Personnel; Floyd W. Wilcox, 

Reynolds Electrical and Engineering Company; December 1, 1961; SRDB Ref ID: 8104 

Wilcox, 1962, Operation Guides for Tunnel Area, Information Bulletin #20; Floyd W. Wilcox; July 

10, 1962; SRDB Ref ID: 8040 

Wruble, 1990, Nevada Test Site Annual Site Environmental Report-1989, Volume One, 

DOE/NV/10630-11; Donald T. Wruble and Elizabeth M. McDowell; November 1990; SRDB Ref ID: 

1763