December 13, 2005 

Mr. David Staudt 

Center for Disease Control and Prevention 

Acquisition and Assistance Field Branch 

Post Office Box 18070 

626 Cochrans Mill Road – B-140 

Pittsburgh, PA 15236-0295 

Re: Contract No. 200-2004-03805, Task Order 1: Draft Review of the NIOSH Site Profile for 

the Nevada Test Site 

Dear Mr. Staudt: 

S. Cohen & Associates (SC&A) is pleased to submit our draft review of the NIOSH Site Profile for the 

Nevada Test Site, consisting of our evaluation of “Rev. 00” of the six technical basis documents (TBDs) 

for introduction, site description, and occupational medical, environmental internal, and external dose, 

respectively. We understand that some or all of these TBDs are under active revision and have reflected 

that understanding with respect to findings and issues that we have identified to the extent possible. 

While this report was completed in October 2005, it was submitted to the Department of Energy on 

November 3, 2005, for the purpose of confirming that there is no classified or Unclassified Controlled 

Nuclear Information (UCNI) national security information inadvertently included. DOE returned this 

draft report with such certification in a December 1, 2005 letter. Attachments 4 and 5 of this report were 

submitted separately to DOE for review, with similar confirmations received on December 6 and 

December 13, respectively. SC&A will prepare an issue resolution matrix based on this review and 

submit it to the Board at least 1 week prior to its January 24-26 meeting. 

Sincerely, 

John Mauro, PhD, CHP 

Project Manager 

cc: P. Ziemer, PhD, Board Chairperson 

Advisory Board Members 

L. Wade, PhD, NIOSH 

L. Elliott, NIOSH 

J. Neton, PhD, NIOSH 

S. Hinnefeld, NIOSH 

Z. Homoki-Titus, NIOSH 

A. Brand, NIOSH 

H. Behling, PhD, SC&A 

J. Lipzstein, PhD, SC&A 

A. Makhijani, PhD, SC&A 

J. Fitzgerald, Saliant 

K. Robertson-DeMers, CHP, Saliant 

S. Ostrow, PhD, SC&A 

K. Behling, SC&A 

Project File (ANIOS/001/06)
 
 

Draft 

ADVISORY BOARD ON 

RADIATION AND WORKER HEALTH 

National Institute of Occupational Safety and Health 

Review of the NIOSH Site Profile for the Nevada Test Site 

Contract No. 200-2004-03805 

Task Order No. 1 

SCA-TR-TASK1-0006
 

Prepared by 

S. Cohen & Associates 

6858 Old Dominion Drive, Suite 301 

McLean, Virginia 22101 

Saliant, Inc.
 

5579 Catholic Church Road 

Jefferson, Maryland 21755
 

December 13, 2005 

Disclaimer 

This document is made available in accordance with the unanimous desire of the Advisory Board 

on Radiation and Worker Health (ABRWH) to maintain all possible openness in its 

deliberations. However, the ABRWH and its contractor, SC&A, caution the reader that at the 

time of its release, this report is pre-decisional and has not been reviewed by the Board for 

factual accuracy or applicability within the requirements of 42 CFR 82. This implies that once 

reviewed by the ABRWH, the Board’s position may differ from the report’s conclusions. Thus, 

the reader should be cautioned that this report is for information only and that premature 

interpretations regarding its conclusions are unwarranted. 
Effective Date: 

December 13, 2005 

Revision No. 

0 

Document No. 

SCA-TR-TASK1-0006 

Page No. 

2 of 158 

S. COHEN & ASSOCIATES: Document No. 

SCA-TR-TASK1-0006 

Technical Support for the Advisory Board on 

Radiation & Worker Health Review of 

Effective Date: 

Draft — December 13, 2005 

NIOSH Dose Reconstruction Program Revision No. 0 – (Draft) 

REVIEW OF THE NIOSH SITE PROFILE 

FOR THE NEVADA TEST SITE Page 2 of 158 

Task Manager: 

________________________ Date: ___________ 

Arjun Makhijani 

Supersedes: 

N/A 

Project Manager: 

________________________ Date: ___________ 

John Mauro 
Effective Date: 

December 13, 2005 

Revision No. 

0 

Document No. 

SCA-TR-TASK1-0006 

Page No. 

3 of 158 

TABLE OF CONTENTS 

Acronyms and Abbreviations ..........................................................................................................6 

1.0 Executive Summary .............................................................................................................9 

1.1 Summary of Strengths............................................................................................10 

1.2 Summary of Findings.............................................................................................10 

1.3 Opportunities for Improvement .............................................................................13 

2.0 Scope and Introduction ......................................................................................................15 

2.1 Review Scope.........................................................................................................15 

2.2 Review Approach...................................................................................................17 

2.3 Report Organization...............................................................................................18 

3.0 Assessment Criteria and Methods......................................................................................19 

3.1 Objectives ..............................................................................................................19 

3.1.1	 Objective 1: Completeness of Data Sources .............................................19 

3.1.2	 Objective 2: Technical Accuracy..............................................................19 

3.1.3	 Objective 3: Adequacy of Data.................................................................20 

3.1.4	 Objective 4: Consistency Among Site Profiles.........................................20 

3.1.5	 Objective 5: Regulatory Compliance ........................................................20 

4.0	 Site Profile Strengths .........................................................................................................24 

5.0	 Findings..............................................................................................................................25 

5.1	 Issue 1: Radionuclide Lists ...................................................................................25 

5.2	 Issue 2: Reactor Re-Entry Personnel ....................................................................26 

5.3	 Issue 3: Large Particle Doses During Nuclear Weapons Tests.............................29 

5.4	 Issue 4: Ingestion due to Oro-Nasal Breathing .....................................................30 

5.5	 Issue 5: Environmental Occupational Dose ..........................................................30 

5.5.1	 Overall Environmental Dose Finding ........................................................30 

5.5.2	 Internal Occupational Environmental Dose ...............................................31 

5.5.3	 External Occupational Environmental Dose..............................................40 

5.5.4	 Radon Dose................................................................................................44 

5.5.5	 Occupational Iodine-131 Data ...................................................................46 

5.5.6	 Soil Ingestion .............................................................................................46 

5.6	 Issue 6: Internal Dose............................................................................................57 

5.6.1	 Overview....................................................................................................57 

5.6.2	 Important Details as Regards Interpretation of Various Kinds of 

Internal Dose Data are Not Included in the NTS TBD Vol. 5...................58 

5.6.3	 Lack of Early Internal Monitoring Data ....................................................60 

5.6.4	 Assigning Only Environmental Doses to Workers Thought Not to be 

at Risk of Internal Exposure may Not Capture the Full Extent of 

Radionuclide Intake ...................................................................................63 

5.6.5	 The NTS TBD Vol. 5 has Not Adequately Explored Intake of 

Radionuclides via the Ingestion Pathway ..................................................64 

5.6.6	 The NTS TBD Vol. 5 does Not Adequately Consider the Possibility 

of Exposure to Different Enrichments of Uranium....................................65 
Effective Date: 

December 13, 2005 

Revision No. 

0 

Document No. 

SCA-TR-TASK1-0006 

Page No. 

4 of 158 

5.6.7	 Use of ORAUT-OTIB-0002 ......................................................................65 

5.6.8	 Miscellaneous Internal Dose Issues ...........................................................66 

5.7	 Issue 7: External Dose ..........................................................................................67 

5.7.1	 Overview of External Dose........................................................................67 

5.7.2	 Early Open Window Dose .........................................................................68 

5.7.3	 Data Integrity .............................................................................................68 

5.7.4	 The TBD does Not Contain Complete Instructions for Converting 

External Dosimetry Data into IREP Inputs................................................69 

5.7.5	 Extremity Dosimetry..................................................................................70 

5.7.6	 Angular Dependence of the Individual Monitors for Ground Surface 

Irradiation Geometry Needs to be Taken into Consideration ....................71 

5.7.7	 Neutron Doses............................................................................................72 

5.7.8	 Neutron Exposure During Atmospheric Testing .......................................73 

5.7.9	 Miscellaneous External Dose Issues ..........................................................74 

5.8	 Issue 8: Medical Dose...........................................................................................75 

6.0	 Observations ......................................................................................................................76 

6.1	 Environmental Dose...............................................................................................76 

6.1.1	 Verification is needed of Environmental Monitoring Data Referenced 

in the TBD..................................................................................................76 

6.2	 Internal Dose ..........................................................................................................76 

6.3	 External Dose.........................................................................................................77 

7.0	 Overall Adequacy of the Site Profile as a Basis for Dose Reconstruction ........................79 

7.1 The Five Objectives ...............................................................................................79 

7.1.1	 Objective 1: Completeness of Data Sources .............................................79 

7.1.2	 Objective 2: Technical Accuracy..............................................................84 

7.1.3	 Objective 3: Adequacy of Data.................................................................84 

7.1.4	 Objective 4: Consistency Among Site Profiles.........................................86 

7.1.5	 Objective 5: Regulatory Compliance ........................................................88 

8.0	 References..........................................................................................................................89 

Attachment 1: SC&A Questions to NIOSH..................................................................................93 

Attachment 2: ORAU Written Responses to SC&A Questions ...................................................98 

Attachment 3: Summary of Conference Call on September 9, 2005..........................................109 

Attachment 4: Master Summary of Site Expert Interviews ........................................................125 

Attachment 5: Summary of Interview with William J. Brady, Principal Health 

Physicist (Retired)............................................................................................................149 

Attachment 6: NIOSH Response to Post-September 9, 2005, Conference Call Questions........155
 

Attachment 7: NIOSH Notes on Conversations with Martha DeMarre Sent to SC&A .............157 
Effective Date: 

December 13, 2005 

Revision No. 

0 

Document No. 

SCA-TR-TASK1-0006 

Page No. 

5 of 158 

LIST OF TABLES 

Table 1: Activation Products Important for External Gamma Dose ..........................................25 

Table 2. Skin and Gastrointestinal-Tract Large Particle Beta Doses to Re-entry Workers, 

Table 6. Iodine-131 Releases from Underground and Cratering Tests that Resulted in the 

Table 7. Atmospheric Concentrations of Plutonium-239,240 (pCi m-3) for the Nevada Test 

Phoebus 1B, EP-IV Test ..............................................................................................28 

Table 3: Time-Averaged Resuspension Coefficients.................................................................38 

Table 4: Size of NTS Areas Contaminated with Plutonium-239,240 as Determined by 

Soil Inventory Data......................................................................................................47 

Table 5: Ambient Radiation Measurements at NTS Areas ........................................................48 

Detection of Offsite Radioactivity...............................................................................49 

Site ...............................................................................................................................78 

Table 8. Comparison of Photon Dosimetry ...............................................................................87 

Table 9. Comparison of Neutron Dosimetry..............................................................................87 

Table 10. Comparison of Beta Dosimetry ...................................................................................87 

LIST OF FIGURES 

Figure 1: Portions of the NTS Surveyed by the Radionuclide Inventory and Distribution 

Program........................................................................................................................50 

Figure 2: Distribution of Plutonium-239,240 on NTS as of January 1, 1990 .............................51 

Figure 3: Locations of Atmospheric and Underground Nuclear Tests, Industrial Sites, and 

Operating Radioactive Waste Management Sites on the Nevada Test Site.................52 

Figure 4: NTS Ionisation Chamber Sampling Locations at NTS, July 1966 to June 1967, 

marked 3a, 5a, 6a, 12a, 18a, 20a, 23a, 27a ..................................................................53 

Figure 5: Areas with Cesium-137 Contamination and Approximate Locations of NTS 

Ionisation Chamber Sampling Locations (hexagons) at NTS, July 1966 to June 

1967..............................................................................................................................54 

Figure 6: Offsite Dose Rates Related to Ploughshare Test SCHOONER (from area 19)...........55 

Figure 7: Correlation between Ambient External Gamma Radiation and Beta Activity in 

Air at the Nevada Test Site, July 1966 to June 1967 ...................................................57 
 

 

Effective Date: 

December 13, 2005 

Revision No. 

0 

Document No. 

SCA-TR-TASK1-0006 

Page No. 

6 of 158 

ACRONYMS AND ABBREVIATIONS 

ACL Administrative Control Limit 

Advisory Board Advisory Board on Radiation and Worker Health 

AEC Atomic Energy Commission 

AFB Air Force Base 

Anti-Cs Anti-contamination Clothing 

AP Anteroposterior 

ASER Annual Site Environmental Reports 

ATM Atmospheric 

BN Bechtel Nevada 

BREN Bare Reactor Experiment Nuclear 

CAT Computed Axial Tomography 

CDC Centers for Disease Control and Prevention 

CFR Code of Federal Regulations 

CP Control Point 

DAF Device Assembly Facility 

DNA Defense Nuclear Agency 

DOD Department of Defense 

DOE Department of Energy 

DOECAP Department of Energy Contractor Assurance Program 

DRI Desert Research Institute 

DRP Dosimetry Research Project 

DTPA Diethylenetriaminepentaacetate 

DTRA Defense Threat Reduction Agency 

DU Depleted Uranium 

EEOICPA Energy Employees Occupational Illness Compensation Program Act 

EPA Environmental Protection Agency 

GI Gastrointestinal 

GSA General Services Administration 

HEU Highly Enriched Uranium 

HP Health Physics or Health Physicist 

HRC Historical Records Center 
Effective Date: 

December 13, 2005 

Revision No. 

0 

Document No. 

SCA-TR-TASK1-0006 

Page No. 

7 of 158 

HTO Tritiated Water Vapor 

ICRP International Commission on Radiological Protection 

IH Industrial Hygiene 

IMBA Integrated Modules for Bioassay Analysis 

INEEL Idaho National Engineering and Environmental Laboratory 

IREP Interactive RadioEpidemiological Program 

LANL Los Alamos National Laboratory 

LLNL Lawrence Livermore National Laboratory 

LOD Limits of Detection 

MDA Minimum Detectable Activity 

MDD Minimum Detectable Dose 

NAS National Academy of Sciences 

NCRP National Council on Radiation Protection and Measurements 

NESHAPS National Emission Standards for Hazardous Air Pollutants 

NIOSH National Institute for Occupational Safety and Health 

NNSA National Nuclear Security Administration 

NRDL Naval Radiological Defense Laboratory 

NRDS Nuclear Rocket Development Station 

NSO Nevada Safety Operations 

NTA Nuclear Test Archive 

NTA film Neutron Track Type A Film 

NTPR Nuclear Test Personnel Review 

NTS Nevada Test Site 

NTS TBD Nevada Test Site Technical Basis Document 

NTSER Nevada Test Site Environmental Report 

OCAS Office of Compensation Analysis and Support 

ORAU Oak Ridge Associated Universities 

PFG Photofluorography 

PIC Pocket Ionization Chamber 

POC Probability of Causation 

PPE Personnel Protective Equipment 

PPG Pacific Proving Grounds 
 

 

Effective Date: 

December 13, 2005 

Revision No. 

0 

Document No. 

SCA-TR-TASK1-0006 

Page No. 

8 of 158 

RDC Radon Daughter Concentration 

REECo Reynolds Electrical Engineering Company 

REMS Radiation Exposure Monitoring System 

RIDP Radionuclide Inventory and Distribution Program 

RIF Reduction-in-force 

RSSU Radiation Safety Support Unit 

RWP Radiation Work Permit 

SAIC Science Applications International Corporation 

SC&A S. Cohen and Associates 

SFCP Spent Fuel Climax Project 

SNL Sandia National Laboratory 

SSN Social Security Number 

TBD Technical Basis Document 

TIB Technical Information Bulletin 

TLD Thermoluminescent Dosimeter 

UG Underground 

WBC Whole-Body Count 

WIPP Waste Isolation Pilot Plant 

WL Working Level 

WLM Working Level Month 
Effective Date: 

December 13, 2005 

Revision No. 

0 

Document No. 

SCA-TR-TASK1-0006 

Page No. 

9 of 158 

1.0 EXECUTIVE SUMMARY 

This report presents the S. Cohen and Associates (SC&A, Inc.) evaluation of the site profile, 

Technical Basis Document for the Nevada Test Site (ORAUT-TKBS-0008), which was 

published in six volumes numbered ORAUT-TKBS-0008-1 through ORAUT-TKBS-0008-6, 

inclusive, referred to in this report as the Nevada Test Site (NTS) technical basis document 

(TBD) Vols. 1 through 6. This review covers all six volumes of the NTS TBD. It includes a 

review of related NTS records and documented exchanges with the National Institute of 

Occupational Safety and Health (NIOSH) and Oak Ridge Associated Universities (ORAU) 

through questions sent by SC&A (Attachment 1), written answers from NIOSH and its 

contractors (Attachment 2), and a conference call with NIOSH and its contractors 

(Attachment 3). This review also includes interviews with site experts conducted by SC&A in 

Nevada (Attachment 4) and by telephone (Attachment 5). This report was prepared at the 

request of the Advisory Board on Radiation and Worker Health (Advisory Board). SC&A is the 

technical support contractor of the Advisory Board. 

The NTS TBD was evaluated for its completeness, technical accuracy, adequacy of data, 

compliance with stated objectives, and consistency with other site profiles, as stipulated in the 

SC&A Standard Operating Procedure for Performing Site Profile Reviews (SC&A 2004). As 

“living” documents, TBDs are constantly being revised as new information, experience, or issues 

arise. The results of reviews of other documents by SC&A, including reviews of other TBDs 

and of NIOSH procedures (SC&A 2005d) have been incorporated into the present report as 

appropriate. 

This report is a review of Rev. 00 of the NTS TBD. The six volumes of Rev. 00 were published 

between February 2, 2004, and September 30, 2004. They represent the most recent published 

version of the NTS TBD on NIOSH’s web site as of August 30, 2005. From the written response 

to SC&A questions, sent to SC&A on September 8, 2005 (Attachment 2), and the conference call 

of September 9, 2005, SC&A learned that NIOSH is close to completing a revision of the NTS 

TBD (Rev. 01). However, this revision has not yet been published. 

Following the introduction and a description of the criteria and methods employed to perform the 

review, the report discusses the strengths of the TBD, followed by a description of the major 

issues identified during our review. The issues were carefully reviewed with respect to the 

following five review criteria specified in the SC&A 2004: 

(1) Completeness of data sources 

(2) Technical accuracy 

(3) Adequacy of data 

(4) Consistency among site profiles 

(5) Regulatory compliance 

Several of the issues were designated as findings, because they represent deficiencies in the NTS 

TBD that need to be corrected, and which have the potential to substantially impact at least some 

dose reconstructions. Revision 00 of the NTS TBD mainly covers the period from 1963 onwards 

—that is, from the time that atmospheric testing was no longer done at NTS. However, there are 

technical comments and conclusions on the pre-1963 period in the NTS TBD. Furthermore, 
Effective Date: 

December 13, 2005 

Revision No. 

0 

Document No. 

SCA-TR-TASK1-0006 

Page No. 

10 of 158 

some of the issues are common to the pre- and post-atmospheric testing period. As a result, 

SC&A has addressed some of the technical issues relating to the atmospheric testing period, and 

has discussed its findings for this period. Except for the findings that relate specifically to 

conclusions or technical statements in the NTS TBD about the atmospheric testing period, the 

SC&A findings in regard to that period should be viewed as suggestions for incorporation into 

future revisions of the NTS TBD. 

1.1 SUMMARY OF STRENGTHS 

The following strengths were noted in the NTS TBD: 

• 	 After 1957, everyone was badged. After 1966, there was an integrated film and ID 

badge. The characteristics of the dosimeters are described in the NTS TBD. The 

approach to external dose estimation is, overall, technically sound and claimant favorable 

in those cases where data are available and sound. 

• 	 Radionuclide lists are context-specific. This is important, given the variety of 

radionuclides at NTS, and the differences in radionuclides in different NTS projects and 

environments. 

• 	 A wide variety of methods to assess internal dose were employed as the internal 

dosimetry program at the NTS matured. The TBD makes good use of these methods for 

the purpose of reconstructing internal doses to workers. 

• 	 Tritium exposures were recognized as requiring monitoring in the late 1950s. The TBD 

makes reference to and use of this data. 

1.2 SUMMARY OF FINDINGS 

Finding 1: Radionuclide lists are not complete for several aspects of the NTS operations. 

Finding 2: The NTS TBD does not provide adequate guidance for estimating doses associated 

with reactor propulsion tests, notably doses to early re-entry personnel. These doses may be 

dominated by large particles incorporating short-lived fission products. Doses to the skin, 

gonads, and gastrointestinal (GI) tract appear to be particularly important. 

Finding 3: The TBD has not adequately considered large particle doses to personnel entering 

nuclear weapons test areas within hours or days of the test. Reactor test studies indicate that skin 

and GI-tract doses to early re-entry personnel may far exceed doses estimated via the fine 

particle inhalation or deposition pathway. 

Finding 4: Ingestion of large particles due to oro-nasal breathing may increase GI-tract doses to 

workers who re-entered weapons and reactor testing areas shortly after the tests. 

Finding 5: Environmental occupational dose during weapons testing is not adequately 

addressed in the TBD. 
Effective Date: 

December 13, 2005 

Revision No. 

0 

Document No. 

SCA-TR-TASK1-0006 

Page No. 

11 of 158 

Finding 6: Resuspension intake estimates are not scientifically defensible or claimant favorable 

due to a variety of factors. The doses estimated by using the procedures specified in the TBD 

may underestimate doses by more than an order of magnitude. The following summarizes the 

various issues that need to be addressed with respect to worker doses from resuspension: 

• 	 NTS soil contamination data and the TBD’s analysis of the data to derive air 

concentrations are inadequate. As a result, resuspension doses may be significantly 

underestimated. 

• 	 Survey grid in the “affected areas” may not be adequate to detect hot spots. 

• 	 Measurements of soil inventory of radionuclides in areas thought to be relatively 

unaffected may not be adequate to identify all significant hot spots. 

• 	 The resuspension factor used in the TBD is questionable. 

• 	 The TBD method to assign resuspension doses to workers where the location is not 

known may underestimate the exposure. 

• 	 The TBD does not evaluate resuspension exposure for monitored workers. Adjustments 

to radionuclide intake may be necessary for some monitored workers. 

• 	 Some solubility assumptions for resuspended radionuclides are not scientifically 

appropriate. 

• 	 A dust loading approach may be more appropriate than using resuspension factors for 

estimating resuspension intakes. 

Finding 7: Occupational environmental dose needs to be re-examined with explicit 

consideration given to the time period of testing. The following are the issues that need to be 

examined: 

• 	 Representativeness of data for a given area needs to be further evaluated. 

• 	 Is it claimant favorable to assign 1967 data for the time period 1963 to 1966? 

• 	 Data for 1968 though 1976 are missing. The TBD has not specified an approach to 

estimating external environmental dose for these years. 

• 	 Pre-1963 period external environmental dose estimation procedure is not addressed in the 

TBD. 

• 	 External environmental dose estimation for monitored workers needs to be more 

comprehensively evaluated. 
 

Effective Date: 

December 13, 2005 

Revision No. 

0 

Document No. 

SCA-TR-TASK1-0006 

Page No. 

12 of 158 

• 	 Conclusions regarding external environmental dose for unmonitored and monitored 

workers need to be evaluated further. 

Finding 8: Radon exposure in tunnels needs to be more thoroughly evaluated and radon 

exposure in the Gravel Gerties needs to be evaluated. 

Finding 9: Accuracy of HTO (tritiated water vapor) sampling is questionable. 

Finding 10: The lack of 131I data for non-monitored workers needs to be addressed in the TBD. 

Finding 11: The soil ingestion pathway needs to be addressed in the TBD as part of the 

environmental dose estimation process. 

Finding 12: Numerous issues related to the reconstruction of internal dose need to be 

investigated, including the following: 

• 	 Important details as regards interpretation of various kinds of internal dose data are not 

included in the NTS TBD Vol. 5. 

• 	 There are no internal monitoring data until late 1955, or possibly 1956. After that time 

period, bioassay data are sparse in terms of radionuclide coverage until the 1960s. 

Further, the integrity of external dose data for some groups of workers during this time 

period is open to question. Therefore, internal dose estimation in this context is likely to 

be complex and difficult at best for this time period for most radionuclides. 

• 	 Assigning only environmental doses to workers thought not to be at risk of internal 

exposure may not capture the full extent of radionuclide intake. 

• 	 The NTS TBD Vol. 5 has not adequately explored intake of radionuclides via the 

ingestion pathway. 

• 	 The NTS TBD Vol. 5 does not adequately consider the possibility of exposure to 

different enrichments of uranium.
 

• 	 The recommendation in the NTS TBD (Vol. 5, pg. 35) that the initial evaluation of 

internal dose to non-metabolic organs be done using ORAUT-OTIB-0002 is not in 

accordance with the restrictions for the use of this guidance document. ORAUT-OTIB0002 is restricted to post-1971 workers who did not re-enter tunnels. Furthermore, any 

use of ORAUT-OTIB-0002 should be justified by examining radionuclide lists and the 

reasonableness of using a one-time intake. 

Finding 13: Protocols for reconstructing external dose during testing need to be further 

developed, and the guidance for reconstructing doses to workers subsequent to testing needs to 

explore and address a number of issues. These issues include the following: 
Effective Date: 

December 13, 2005 

Revision No. 

0 

Document No. 

SCA-TR-TASK1-0006 

Page No. 

13 of 158 

• 	 Open window dose was not recorded until 1966. As such, there is the issue of how beta 

dose is to be estimated up to that time. NIOSH has said it will address this question in 

Rev. 01. 

• 	 Data integrity questions exist for at least some job types regarding the external dose 

record due to a reported off-normal practice of the intentional non-use of individual 

dosimeters during work in radiation areas. The problems may extend to the mid-1960s or 

possibly even into the 1970s. 

• 	 The TBD does not contain complete instructions for converting external dosimetry data 

into IREP inputs. 

• 	 The NTS TBD Vol. 6 does not contain information about extremity dosimetry. 

• 	 The status of NTS bomb assembly workers and their exposure records appears to be 

unclear so far as the NIOSH set of TBDs is concerned. 

• 	 Angular dependence of the individual monitors for ground surface irradiation geometry 

needs to be taken into consideration. 

• 	 Neutron dose data are lacking until 1966 and are partial until 1979. The TBD does not 

provide a basis for estimating some neutron doses. 

• 	 The assumption that neutron exposure during atmospheric testing “was practically nonexistent” is not based on an analysis of the problem and may not be correct for some 

groups of workers. 

Finding 14: The guidance regarding the reconstruction of medical doses needs to address 

additional medical exposure scenarios, including the use of photofluorography, and additional 

uncertainties associated with routine chest x-rays. 

1.3 OPPORTUNITIES FOR IMPROVEMENT 

SC&A understands that NIOSH is preparing to publish a revised NTS TBD (see Attachments 2 

and 3). It would be desirable to evaluate the following suggestions for incorporation into the 

revised TBD: 

(1) Radionuclide lists should be more complete, especially for the period to 1967, when 

internal dose data are either lacking or not plentiful or detailed enough. 

(2) NIOSH should fully evaluate the Naval Radiological Defense Laboratory (NRDL) 

methods for estimating certain aspects of dose—those from large, hot particles—to early 

re-entry employees in the reactor propulsion test areas. The data and methods appear to 

be useful, not only for assessing reactor area doses, but also for atmospheric weapon 

tests, underground tests that vented accidentally, and possibly for post-1970 underground 

tests. 
Effective Date: 

December 13, 2005 

Revision No. 

0 

Document No. 

SCA-TR-TASK1-0006 

Page No. 

14 of 158 

(3) In addressing the lack of beta dose data prior to 1966, NIOSH should evaluate whether 

the usual approach of applying beta-gamma ratios is applicable, in view of the fact that 

the gamma dose at 1 m is determined mainly by fine particle deposition, whereas some 

doses, notably skin and GI-tract doses, appear to be dominated by large particles for 

certain groups of workers. 

(4) NIOSH should carefully evaluate the issue of external dosimetry data integrity with a 

view toward determining how widespread the problem of not wearing badges might have 

been and how long it lasted. 

(5) Guidance on some issues of technical detail, such as the effect of heat on film badges and 

thermoluminescent dosimeters (TLDs) stored in personal vehicles and organ dose 

geometry relative to recorded dosimeter dose, should be explicitly developed. 

(6) NIOSH should make a greater effort to take into account site expert information and 

investigate worker accounts. The on-site, first-hand experience of site experts enables 

them to provide original perspectives and information concerning site practices and 

exposure histories. NIOSH has incorporated a limited amount of worker input into the 

latest version of the TBD. However, NIOSH’s use of experts with vast knowledge, such 

as Barton Hacker and William Brady, has been minimal or non-existent. 

(7) NIOSH should revamp its approach to environmental doses by evaluating the dust 

loading approach. Air concentration data should be re-evaluated in the light of the Los 

Alamos study on large particle undercounting at high wind speeds discussed in this 

review. 

(8) NIOSH needs to make a much more complete review of many data sources in order to 

address the findings in Section 1.2 above. 

(9) The National Academy of Sciences (NAS) report titled, A Review of the Dose 

Reconstruction Program of the Defense Threat Reduction Agency (NAS 2003), contains 

numerous findings and recommendations pertaining to the reconstruction of doses for 

military personnel exposed at the NTS. Many of these findings and recommendations 

may also apply to the reconstruction of claimant doses under the Energy Employees 

Occupational Illness Compensation Program Act (EEOICPA) and should be considered 

in future revisions of the TBD. 

(10) The NTS TBD needs to be more compete in its coverage of periods and facilities, 

including atmospheric testing (which was largely excluded from Rev. 00 and which will 

be covered in Rev. 01), aspects of waste handling and packaging, bomb assembly (if 

required in the NTS TBD) and decommissioning, including the facilities mentioned in 

Section 2.2.31 of the TBD. 

More detailed suggestions for improvement are mentioned or discussed as part of the various 

findings in Section 5 and the discussion in Section 7 of this review. 
Effective Date: 

December 13, 2005 

Revision No. 

0 

Document No. 

SCA-TR-TASK1-0006 

Page No. 

15 of 158 

2.0 SCOPE AND INTRODUCTION 

2.1 REVIEW SCOPE 

Under the Energy Employees Occupational Illness Compensation Program Act of 2000 

(EEPOICPA) and Federal regulations defined in Title 42, Part 82, Methods for Radiation Dose 

Reconstruction Under the Energy Employees Occupational Illness Compensation Program, of 

the Code of Federal Regulations (42 CFR Part 82), the Advisory Board on Radiation and Worker 

Health (Advisory Board) is mandated to conduct an independent review of the methods and 

procedures used by the National Institute for Occupational Safety and Health (NIOSH) and its 

contractors for dose reconstruction. As a contractor to the Advisory Board, S. Cohen and 

Associates (SC&A, Inc.) has been charged under Task 1 to support the Advisory Board in this 

effort by independently evaluating a select number of site profiles that correspond to specific 

facilities at which energy employees worked and were exposed to ionizing radiation. 

This report provides a review of the following six technical basis documents (TBDs) related to 

historical occupational exposures at the Nevada Test Site (NTS): 

• 	 ORAUT-TKBS-0008-1, Technical Basis Document for the Nevada Test Site – 

Introduction (Rollins 2004a) 

• 	 ORAUT-TKBS-0008-2, Technical Basis Document for the Nevada Test Site – 

Site Description (Rollins 2004b) 

• 	 ORAUT-TKBS-0008-3, Technical Basis Document for the Nevada Test Site – 

Occupational Medical Dose (Rollins 2004c) 

• 	 ORAUT-TKBS-0008-4, Technical Basis Document for the Nevada Test Site – 

Occupational Environmental Dose (Rollins 2004d) 

• 	 ORAUT-TKBS-0008-5, Technical Basis Document for the Nevada Test Site – 

Occupational Internal Dose (Rollins 2004e) 

• 	 ORAUT-TKBS-0008-6, Technical Basis Document for the Nevada Test Site – 

Occupational External Dosimetry (Rollins 2004f) 

These documents are referred to in this review as NTS TBD Vols. 1 through 6. These six 

volumes are supplemented by technical information bulletins (TIBs), which provide additional 

guidance to the dose reconstructor. SC&A, in support of the Advisory Board, has critically 

evaluated the NTS TBDs and supplementary and supporting documents in order to: 

• 	 Determine the completeness of the information gathered by NIOSH, with a view to 

assessing its adequacy and accuracy in supporting individual dose reconstructions 

• 	 Assess the technical merit of the data/information 

• 	 Assess NIOSH’s guidelines for the use of the data in dose reconstructions 
Effective Date: 

December 13, 2005 

Revision No. 

0 

Document No. 

SCA-TR-TASK1-0006 

Page No. 

16 of 158 

SC&A’s review of the six volumes that comprise the TBD, along with its supporting 

supplemental documentation, focuses on the quality and completeness of the data that 

characterized the facility and its operations, and the adequacy of these data in dose 

reconstruction. The review was conducted in accordance with Standard Operating Procedure 

for Performing Site Profile Reviews (SC&A 2004), which was approved by the Advisory Board. 

The review is directed at “sampling” the site profile analyses and data for validation purposes. 

The review does not provide a rigorous quality control process, whereby actual analyses and 

calculations are duplicated or verified. The scope and depth of the review are focused on aspects 

or parameters of the site profile that would be particularly influential in dose reconstructions, 

bridging uncertainties, or correcting technical inaccuracies. This review does not explicitly 

address the issue of radiation exposures to cleanup workers and decommissioning workers, as 

that is not addressed in the TBDs. 

The six volumes of the NTS TBD are supposed to serve as site-specific guidance documents to 

be used in support of dose reconstructions. While dose reconstructors use other data, 

information, and guidance documents in making dose estimates, site profiles have the purpose of 

providing dose reconstructors with consistent general information and specifications to support 

their individual dose reconstructions. This report was prepared by SC&A to provide the 

Advisory Board with an evaluation of whether and how the TBDs can support the various types 

of dose reconstruction estimates that NIOSH performs—minimum for compensation only, 

maximum, with worst-case assumptions to be used for denial only, and “best-case” or 

“reasonable” dose estimates to be used for both compensation and denial, according to the 

probability of causation corresponding to the dose estimate. The criteria for evaluation include 

whether the TBDs provide a basis for scientifically supportable and claimant-favorable dose 

reconstructions that systematically resolves uncertainties in favor of the claimant as required by 

42 CFR 82, which is the regulation governing the dose reconstruction process. 

The basic principle of dose reconstruction is to characterize the radiation environments to which 

workers were exposed and determine the levels of exposure the workers received in those 

environments through time. The hierarchy of data used for developing dose reconstruction 

methodologies is dosimeter readings and bioassay data, coworker data and workplace monitoring 

data, and process description information or source term data. 

The case of the NTS is, in many ways, unique because of the hundreds of nuclear weapons tests, 

as well as safety tests with nuclear materials that were conducted there. These tests included 

both atmospheric tests (until 1963) and underground tests (from 1961 onward). In the latter 

category, there were tests that vented significant amounts of radioactivity. Safety tests with 

plutonium have left many areas contaminated. Such activities have left significant amounts of 

contamination in many parts of the site. Testing of experimental nuclear reactors for possible 

use to power rocket engines was also done at NTS. Since fission products and neutron activation 

products were created in large amounts in ways that had the potential to give rise to exposure to 

short-lived radionuclides, the assessment of exposure potential at NTS is an unusually complex 

matter. A variety of other activities, such as assembly of test weapons and management of 

wastes from other sites, add to this complexity. 
Effective Date: 

December 13, 2005 

Revision No. 

0 

Document No. 

SCA-TR-TASK1-0006 

Page No. 

17 of 158 

2.2 REVIEW APPROACH 

SC&A’s review of the TBDs and supporting documentation concentrated on determining the 

completeness of data collected by NIOSH, the adequacy of existing NTS personnel and 

environmental monitoring data, and the evaluation of key dose reconstruction assumptions. Site 

expert interviews were conducted with current and former NTS workers. Also included were 

workers who supported testing operations, but worked at either Lawrence Livermore National 

Laboratory (LLNL) or Los Alamos National Laboratory (LANL). 

All review comments apply to the Rev. 00 versions of the NTS TBD cited above, since they are 

the most recent published versions. SC&A was informed on September 9, 2005, that NIOSH is 

close to completing and publishing Rev. 01 of the NTS TBD. This revision is expected to cover 

the atmospheric testing period. Revision 00 mainly covers the period from 1963 onward. 

However, Rev. 00 has several material guidelines and conclusions about the atmospheric testing 

period, such as the conclusion that neutron doses from atmospheric testing were not important, or 

which radioisotopes were “of concern for dose” (NTS TBD Vol. 5, Table 5D-13, pg. 59). This 

SC&A review includes findings for both periods. Unless explicitly stated, the findings on the 

atmospheric testing period should not be viewed as deficiencies of Rev. 00, but as suggestions 

for consideration by dose reconstructors for this period. 

On May 6, 2005, SC&A sent questions to NIOSH as part of its evaluation of the TBD. These 

questions are reproduced in Attachment 1. ORAU sent written responses to the comments on 

September 8, 2005; they are reproduced in Attachment 2. A conference call was held with 

NIOSH and contractor personnel, including some of those preparing the TBD and dose 

reconstructors performing work on NTS individual dose reconstructions. A summary of that 

conference call is included here as Attachment 3. 

Site expert interviews were conducted to help SC&A obtain a comprehensive understanding of 

the radiation protection program, site operations, and environmental contamination. 

Attachment 4 provides summaries of the interviews conducted by SC&A by teleconference or in 

person in Las Vegas during the course of this review. The site experts included current and 

former staff from radiation control, operations, environmental monitoring, maintenance, and 

other support organizations. These interviews were conducted during the course of the NTS Site 

Profile Review. An integrated summary is provided in Attachment 4. The summary is a 

paraphrase of conversations held with a number of site experts, rather than a verbatim transcript. 

Their statements have been grouped into categories to provide a linkage with various portions of 

the NTS Site profile. References to the names of specific site experts have been omitted for 

privacy reasons. These individuals were given the opportunity to review the interview summary 

for accuracy. This is an important safeguard against missing key issues or misinterpreting some 

vital piece of information. 

SC&A also held a telephone interview with William J. Brady, who worked at the site from 1952 

to 1991, when he retired as Principal Health Physicist. A summary of that interview is 

reproduced in Attachment 5. Mr. Brady gave permission to SC&A to include his name in the 

interview summary. While none of the interviews were classified, they were submitted to the 

DOE along with the summaries in Attachments 4 and 5 for declassification review as a 

precautionary measure. 
Effective Date: 

December 13, 2005 

Revision No. 

0 

Document No. 

SCA-TR-TASK1-0006 

Page No. 

18 of 158 

2.3 REPORT ORGANIZATION 

In accordance with directions provided by the Advisory Board and with site profile review 

procedures prepared by SC&A and approved by the Advisory Board, this report is organized into 

the following sections: 

(1) Executive Summary 

(2) Scope and Introduction 

(3) Assessment Criteria and Method 

(4) Site Profile Strengths 

(5) Findings 

(6) Observations 

(7) Completeness, data adequacy, technical accuracy, and regulatory compliance, and 

comparison of the NTS TBD with other site profiles 

Based on the issues raised in each of these sections, SC&A prepared a list of findings, which are 

provided in the executive summary. Issues are designated as findings if SC&A believes that they 

represent deficiencies in the TBD that need to be corrected, and which have the potential to have 

a substantial impact on at least some dose reconstructions. These findings are not meant to be 

exhaustive, but rather issues of dosimetric significance that SC&A investigated in more detail in 

order to develop suggestions for improvement of any revisions to the NTS TBD and for use in 

dose reconstruction, as appropriate. Issues can also be designated as observations if they simply 

raise questions, which, if addressed, would further improve the TBDs and might possibly reveal 

deficiencies that would need to be addressed in future revisions of the TBDs. 
Effective Date: 

December 13, 2005 

Revision No. 

0 

Document No. 

SCA-TR-TASK1-0006 

Page No. 

19 of 158 

3.0 ASSESSMENT CRITERIA AND METHODS 

SC&A is charged with evaluating the approach set forth in the site profiles that is used in the 

individual dose reconstruction process. These documents are reviewed for their completeness, 

technical accuracy, adequacy of data, consistency with other site profiles, and compliance with 

the stated objectives, as defined in SC&A Standard Operating Procedure for Performing Site 

Profile Reviews (SC&A 2004). This review is specific to the NTS Site Profile and supporting 

TIBs; however, items identified in this report may be applied to other facilities, especially 

facilities with similar source terms and exposure conditions. The review identifies a number of 

issues, and discusses the degree to which the site profile fulfills the review objectives delineated 

in SC&A 2004. 

3.1 OBJECTIVES 

SC&A reviewed the site profile with respect to the degree to which technically sound judgments 

or assumptions are employed. In addition, the review identifies assumptions by NIOSH that give 

the benefit of the doubt to the claimant. 

3.1.1 Objective 1: Completeness of Data Sources 

SC&A reviewed the site profile with respect to Objective 1, which requires SC&A to identify 

principal sources of data and information that are applicable to the development of the site 

profile. The two elements examined under this objective include (1) determining if the site 

profile made use of available data considered relevant and significant to the dose reconstruction, 

and (2) investigating whether other relevant/significant sources are available, but were not used 

in the development of the site profile. For example, if data are available in site technical reports 

or other available site documents for particular processes, and if the TBDs have not taken into 

consideration these data where they should have, this would constitute a completeness of data 

issue. The Oak Ridge Associated Universities (ORAU) site profile document database, 

including the referenced sources in the TBDs, was evaluated to determine the relevance of the 

data collected by NIOSH to the development of the site profile. Additionally, SC&A evaluated 

records publicly available relating to the NTS site and records provided by site experts. 

3.1.2 Objective 2: Technical Accuracy 

SC&A reviewed the site profile with respect to Objective 2, which requires SC&A to perform a 

critical assessment of the methods used in the site profile to develop technically defensible 

guidance or instructions, including evaluating field characterization data, source term data, 

technical reports, standards and guidance documents, and literature related to processes that 

occurred at NTS. The goal of this objective is to first analyze the data according to sound 

scientific principles, and then to evaluate this information in the context of dose reconstruction. 

If, for example, SC&A found that the technical approach used by NIOSH was not scientifically 

sound or claimant favorable, this would constitute a technical accuracy issue. 
Effective Date: 

December 13, 2005 

Revision No. 

0 

Document No. 

SCA-TR-TASK1-0006 

Page No. 

20 of 158 

3.1.3 Objective 3: Adequacy of Data 

SC&A reviewed the site profile with respect to Objective 3, which requires SC&A to determine 

whether the data and guidance presented in the site profile are sufficiently detailed and complete 

to conduct dose reconstruction, and whether a defensible approach has been developed in the 

absence of data. In addition, this objective requires SC&A to assess the credibility of the data 

used for dose reconstruction. The adequacy of the data identifies gaps in the facility data that 

may influence the outcome of the dose reconstruction process. For example, if a site did not 

monitor all workers exposed to neutrons who should have been monitored, this would be 

considered a gap and thus an inadequacy in the data. An important consideration in this aspect 

of our review of the site profile is the scientific validity and claimant favorability of the data, 

methods, and assumptions employed in the site profile to fill in data gaps. 

3.1.4 Objective 4: Consistency Among Site Profiles 

SC&A reviewed the site profile with respect to Objective 4, which requires SC&A to identify 

common elements within site profiles completed or reviewed to date, as appropriate. In order to 

accomplish this objective, the NTS TBDs were compared to some of the other TBDs reviewed to 

date. This assessment was conducted to identify areas of inconsistencies and determine the 

potential significance of any inconsistencies with regard to the dose reconstruction process. It is 

more limited than for some of SC&A’s other reviews, because none of the other sites whose 

profiles have been reviewed so far had many of the activities at NTS. 

3.1.5 Objective 5: Regulatory Compliance 

SC&A reviewed the site profile with respect to Objective 5, which requires SC&A to evaluate 

the degree to which the site profile complies with stated policy and directives contained in 

42 CFR Part 82. In addition, SC&A evaluated the TBD for adherence to general quality 

assurance policies and procedures utilized for the performance of dose reconstructions. 

In order to place the above objectives into the proper context as they pertain to the site profile, it 

is important to briefly review key elements of the dose reconstruction process, as specified in 

42 CFR Part 82. Federal regulations specify that a dose reconstruction can be broadly placed 

into one of three discrete categories. These three categories differ greatly in terms of their 

dependence on and the completeness of available dose data, as well as on the 

accuracy/uncertainty of data. 

Category 1: Least challenged by any deficiencies in available dose/monitoring data are dose 

reconstructions for which even a partial assessment (or minimized dose(s)) corresponds to a 

probability of causation (POC) value in excess of 50%, and assures compensability to the 

claimant. Such partial/incomplete dose reconstructions with a POC greater than 50% may, in 

some cases, involve only a limited amount of external or internal data. In extreme cases, even a 

total absence of a positive measurement may suffice for an assigned organ dose (based on limits 

of detection (LOD)) that results in a POC greater than 50%. For this reason, dose 

reconstructions in behalf of this category may only be marginally affected by incomplete/missing 

data or uncertainty of the measurements. In fact, regulatory guidelines recommend the use of a 

partial/incomplete dose reconstruction, the minimization of dose, and the exclusion of 
Effective Date: 

December 13, 2005 

Revision No. 

0 

Document No. 

SCA-TR-TASK1-0006 

Page No. 

21 of 158 

uncertainty for reasons of process efficiency, as long as this limited effort produces a POC of 

greater than or equal to 50%. 

Category 2: A second category of dose reconstruction is defined by Federal guidance, which 

recommends the use of “worst-case” assumptions. The purpose of worst-case assumptions in 

dose reconstruction is to derive maximal or highly improbable dose assignments. For example, a 

worst-case assumption may place a worker at a given work location 24 hours per day and 

365 days per year. The use of such maximized (or upper bound) values, however, is limited to 

those instances where the resultant maximized doses yield POC values below 50%, which are 

not compensated. For this second category, the dose reconstructor needs only to ensure that all 

potential internal and external exposure pathways have been considered, and that the approach is 

scientifically supportable. 

The obvious benefit of worst-case assumptions and the use of maximized doses in dose 

reconstruction is efficiency. Efficiency is achieved by the fact that maximized doses avoid the 

need for precise data and eliminates consideration for the uncertainty of the dose. Lastly, the use 

of bounding values in dose reconstruction minimizes any controversy regarding the decision not 

to compensate a claim. 

Although simplistic in design, to satisfy this type of a dose reconstruction, the TBD must, at a 

minimum, provide information and data that clearly identify (1) all potential radionuclides, 

(2) all potential modes of exposure, and (3) upper limits for each contaminant and mode of 

exposure. Thus, for external exposures, maximum dose rates must be identified in time and 

space that correspond to a worker’s employment period, work locations, and job assignment. 

Similarly, in order to maximize internal exposures, highest air concentrations and surface 

contaminations must be identified. 

Category 3: The most complex and challenging dose reconstructions consist of claims where 

the case cannot be dealt with under one of the two categories above. For instance, when a 

minimum dose estimate does not result in compensation, a next step is required to make a more 

complete estimate. Or when a worst-case dose estimate that has assumptions that may be 

physically implausible results in a POC greater than 50%, a more refined analysis is required. A 

more refined estimate may be required either to deny or to compensate. In such dose 

reconstructions, which may be represented as a “reasonable” or “best-case” estimate, NIOSH has 

committed to resolve uncertainties in favor of the claimant. According to 42 CFR Part 82, 

NIOSH interprets “reasonable estimates” of radiation dose to mean the following: 

... estimates calculated using a substantial basis of fact and the application of 

science-based, logical assumptions to supplement or interpret the factual basis. 

Claimants will in no case be harmed by any level of uncertainty involved in 

their claims, since assumptions applied by NIOSH will consistently give the 

benefit of the doubt to claimants. [Emphasis added.] 

NTS TBD Vol. 1, ORAUT-TKBS-0008-1, Technical Basis Document for the Nevada Test Site – 

Introduction, explains the purpose and the scope of the site profile. It also explains the role of 

each TBD in support of the dose reconstruction process. During the course of its review, SC&A 
Effective Date: 

December 13, 2005 

Revision No. 

0 

Document No. 

SCA-TR-TASK1-0006 

Page No. 

22 of 158 

was cognizant of the fact that the site profile is not required by the EEOICPA or by 42 CFR 

Part 82, which implements the statute. Site profiles were developed by NIOSH as a resource to 

the dose reconstructors for identifying site-specific practices, parameter values, and factors that 

are relevant to dose reconstruction. Based on information provided by NIOSH personnel, SC&A 

understands that site profiles are “living” documents, which are revised, refined, and 

supplemented with TIBs, as required, to help dose reconstructors. Site profiles are not intended 

to be prescriptive nor necessarily complete in terms of addressing every possible issue that may 

be relevant to a given dose reconstruction. Hence, the introduction helps in framing the scope of 

the site profile. NIOSH has informed SC&A that Rev. 01 of the NTS TBD is close to 

completion, and that considerable additional information will be included in it. SC&A has made 

comments in this review as to areas of additional information that should be considered for 

inclusion in the revised TBD. 

NTS TBD Vol. 2, ORAUT-TKBS-0008-2, Technical Basis Document for the Nevada Test Site – 

Site Description (Rollins 2004b), is a very important document, because it provides a description 

of the facilities, underground testing, atmospheric testing, and historical information that serve as 

the underpinning for subsequent NTS TBDs. Specifically, this document describes the various 

areas of NTS and the activities that were conducted there. SC&A’s review addresses whether 

the NTS TBD includes dose reconstruction guidelines for all major activities conducted at the 

site. 

NTS TBD Vol. 3, ORAUT-TKBS-0008-3, Technical Basis Document for the Nevada Test Site – 

Occupational Medical Dose (Rollins 2004c), provides a set of procedures for reconstructing the 

radiation exposures of workers from medical radiographic procedures that were required of 

employees at the NTS site. SC&A reviewed this section for technical adequacy and consistency 

with other NIOSH procedures, and compared these with other site profiles. 

NTS TBD Vol. 4, ORAUT-TKBS-0008-4, Technical Basis Document for the Nevada Test Site – 

Occupational Environmental Dose (Rollins 2004d), provides background information and 

guidance to dose reconstructors for reconstructing the doses to unmonitored workers outside of 

the facilities at the site who may have been exposed to routine and episodic airborne emissions 

from these facilities. SC&A’s review also considers special environmental exposure situations 

in which doses may not be fully reflected in exposure records. SC&A reviewed this section from 

the perspective of the source terms and the atmospheric transport, deposition, and resuspension 

models used to derive the external and internal doses to these workers. 

NTS TBD Vol. 5, ORAUT-TKBS-0008-5, Technical Basis Document for the Nevada Test Site – 

Occupational Internal Dose (Rollins 2004e), presents background information and guidance to 

dose reconstructors for deriving occupational internal doses to workers. This section was 

reviewed with respect to background information and guidance regarding the types, mixes, and 

chemical forms of the radionuclides that may have been inhaled or ingested by the workers; the 

recommended assumptions for use in reconstructing internal doses based on whole-body counts 

and bioassay data; the methods recommended for use in the reconstruction of missed internal 

dose; and the methods recommended for characterizing uncertainty in the reconstructed internal 

doses. 
Effective Date: 

December 13, 2005 

Revision No. 

0 

Document No. 

SCA-TR-TASK1-0006 

Page No. 

23 of 158 

NTS TBD Vol. 6, ORAUT-TKBS-0008-6, Technical Basis Document for the Nevada Test Site – 

Occupational External Dose (Rollins 2004f), presents background information and guidance to 

dose reconstructors for deriving occupational external doses to workers. This section was 

reviewed with respect to background information and guidance regarding the different types of 

external radiation (i.e., gamma, beta, and neutron) and the energy distribution of this radiation to 

which the workers may have been exposed. SC&A also reviewed the recommendations for 

converting external dosimetry data to organ-specific doses, the methods recommended for use in 

the reconstruction of missed external doses, and the methods recommended for characterizing 

uncertainty in the reconstructed external doses. 

It is important to note that SC&A’s review of the NTS TBD is not exhaustive. The findings are 

oriented to in-depth consideration of selected issues that SC&A has concluded have a potentially 

significant impact on either the scientific soundness of the dose reconstruction process or the 

claimant favorability of the result of the estimation procedure. In all its reviews, SC&A uses the 

same general criteria in evaluating adequacy of data or completeness of the data search by 

NIOSH. These are large, complex documents, and SC&A used its judgment in selecting those 

issues that we believe are important with respect to dose reconstruction. 

There are three levels of review for this report. First, SC&A team members reviewed the report 

internally. Second, SC&A consultants who had not participated in the preparation of this report 

were asked to review all or portions of the report, according to their specializations. The third 

level, referred to as the expanded review cycle, will consist of a review of this draft by the 

Advisory Board and NIOSH. The first two of these have been completed prior to submittal of 

this report to the Advisory Board. 

The usual procedure, after the Advisory Board and NIOSH have had an opportunity to review 

the draft report, is a comment resolution process, for which a public record is maintained. The 

Advisory Board usually initiates this, in order to resolve as many of the issues as possible and for 

any outstanding differences to be transparent. 
Effective Date: 

December 13, 2005 

Revision No. 

0 

Document No. 

SCA-TR-TASK1-0006 

Page No. 

24 of 158 

4.0 SITE PROFILE STRENGTHS 

In developing a TBD, the assumptions used must be fair, consistent, and scientifically robust, 

and uncertainties and inadequacies in source data must be explicitly addressed. The 

development of the TBD must also consider efficiency in the process of analyzing individual 

exposure histories, so claims can be processed in a timely manner. With this perspective in 

mind, we identified a number of strengths in the NTS TBD. These strengths are listed below and 

described in the following sections: 

(1) After 1957, everyone was badged, and after 1966, there was an integrated film and ID 

badge, which ensured that everyone onsite had external dose monitoring. The integrated 

ID/film badge also made it far more difficult and less likely that employees would 

remove their badges to ensure their ability to continue to work in forward areas. 

(2) The approach to external dose estimation is, overall, technically sound and claimant 

favorable in those cases where data are available and sound. 

(3) Radionuclide lists are context-specific. This is important, given the variety of 

radionuclides at NTS, and the differences in radionuclides in different NTS projects and 

environments. 

(4) A wide variety of methods to assess internal dose were employed as the internal 

dosimetry program at the NTS matured. The TBD makes good use of these methods for 

reconstructing internal doses to workers. 

(5) Tritium exposures in the tunnel environments were recognized as requiring bioassay 

monitoring, which was started in the late 1950s. 

(6) The NTS TBD has identified site in situ and aerial survey data as useful sources from 

which to estimate internal environmental dose. However, as noted in the findings, SC&A 

has considerable reservations about the details of the use of this data. 
 

 

Effective Date: 

December 13, 2005 

Revision No. 

0 

Document No. 

SCA-TR-TASK1-0006 

Page No. 

25 of 158 

5.0 FINDINGS 

SC&A has developed a list of key issues regarding the NTS Site Profile. These issues relate to 

each of the five objectives defined in SC&A 2004. Some issues are related to a particular 

objective, whereas others cover several objectives. Many of the issues raised below are 

applicable to other DOE and Atomic Weapons Employer sites, and should be considered in the 

preparation and revision of other site profiles. 

5.1 ISSUE 1: RADIONUCLIDE LISTS 

Finding 1: Radionuclide lists are not complete for several aspects of NTS operations. 

Table 1 shows the activation products regarded as important in the study by the National 

Research Council of the NAS on nuclear testing evaluating exposures of armed forces personnel 

(NAS 1989). 

Table 1: Activation Products Important for External Gamma Dose 

Radionuclide Half-life Photon energies, principal 

emissions, KeV 

239Np 2.36 days 100, 117, 210, 228, and 278 24Na 15.0 hours 1369 and 2754 

56Mn 2.58 hours 847, 1811, and 2113 

38Cl 37.2 minutes 1642 and 2168 

28Al 2.24 minutes 1779 

46Sc 83.8 days 889 and 1121 

134Cs 2.07 years 569, 605, and 796 

60Co 5.27 years 1173 and 1332 

Notes: 1. Photon energies shown are those cited in NAS 1989. 

2.	 Very short half-life activation products are only relevant in case 

of entry into areas very soon after the test or in case of 

entrainment in fallout affecting personnel. 

Source: NAS 1989, pg. 31 

The extent to which a specific radionuclide would result in exposure would depend on the time 

of entry into the contaminated area and the nature of the test (atmospheric, underground, and 

within those two broad categories, the details of the detonation arrangements). Since the delay 

between the shot and the presence of workers at or near the ground zero of atmospheric tests or 

in tunnels or mined shafts was highly variable, the radionuclides that would be expected to play a 

significant role in exposure would vary according to the test. For instance, if entry was after a 

few hours, 28Al would not be relevant. After a few days (~1 week), the main activation products 

of importance would be 239Np, 46Sc, 134Cs, and 60Co. Note that, in this context, 134Cs is listed as 

an activation product of stable 133Cs. It is also a fission product. Of these radionuclides, the 

TBD only lists 60Co as being relevant for tunnel re-entry and mineback operations (TBD Vol. 2, 

Table 2-2). NIOSH has informed SC&A that Table 2-2 has been revised (see Attachment 2). 
Effective Date: 

December 13, 2005 

Revision No. 

0 

Document No. 

SCA-TR-TASK1-0006 

Page No. 

26 of 158 

The radionuclide lists in Section 5D-4 are also not complete. For instance, the lists in 

Table 5D-10 (NTS TBD Vol. 5, pg. 56) do not include 24Na, 46Sc, or 239Np in the 1-day or 

10-day lists. Strontium-90 is not on the 1-day list. Finally, the radionuclides listed in Table 2-8 

in NTS TBD Vol. 2, do not show time-dependence of the radionuclide list. The year for which 

the inventories were calculated should be stated, in order to account for radionuclide decay (see 

also discussion below on environmental dose). 

The list of radionuclides for atmospheric testing in Table 2-3 appears to be sound. However, the 

table starts with 10-day concentrations. Concentrations should be estimated by hour for the first 

day and by day after that, since entry into areas near ground zero often occurred shortly after the 

tests on the day of the test. Further, Table 5D-13 (NTS TBD Vol. 5, pg. 59), which is a brief 

guide to internal dose during the atmospheric testing period, does not correspond to Table 2-3 

and does not show time-dependence. This is especially important for estimating internal dose 

during the atmospheric testing period, since personal internal monitoring data are lacking for 

almost all radionuclides during this period (see discussion below on internal dose). 

The radionuclide list for the reactor testing areas is also not complete (see Finding 2 below). 

5.2 ISSUE 2: REACTOR RE-ENTRY PERSONNEL 

Finding 2: The NTS TBD does not provide adequate guidance for estimating doses associated 

with reactor propulsion tests, notably those to early re-entry personnel. These doses may be 

dominated by large particles incorporating short-lived fission products. Doses to the skin, 

gonads, and gastrointestinal tract appear to be particularly important. 

Reactor-driven rocket engines were tested at NTS from the late 1950s into the early 1970s. 

These tests were conducted in the open, releasing fission and activation products that were 

deposited near the reactor test area to areas more than forty miles downwind. Area 25 was used 

from 1959 to 1973 “for a series of open-air nuclear reactor, nuclear engine, and nuclear furnace 

tests and for the High Energy Neutron Reactions Experiment” (NTS TBD Vol. 2, pg. 31). Area 

26 was used for the development of a nuclear ramjet engine starting in 1957. 

The open-air reactor tests sent fission products into the air that were dispersed by wind and 

deposited on the ground, with the larger particles being deposited closer to the reactor test site 

and finer particles being deposited farther afield. The total and differential depositions of the 

particles of various sizes would, of course, depend on the size of the test (total energy generated), 

the duration of the test, and meteorological factors. According to the Naval Radiological 

Defense Laboratory (NRDL), it was “necessary for personnel to re-enter the test site area as soon 

as possible” after the test (NRDL 1968, pg. ii). 

NRDL 1968 is a report that was prepared in the context of a reactor test, called the Phoebus 2A, 

EP-II test. That test was to have a power output of 5,000 megawatts for 20 minutes. Given the 

large total energy output, the report used prior reactor test data to estimate expected doses for the 

purpose of deciding re-entry times and durations. Although the NTS TBD cites this report, it 

does not contain any guidance based on it for dose reconstruction purposes, or any evaluation of 

its dose-estimation-related contents. This is surprising, because the data and analysis in the 
 

 

 

 

 

Effective Date: 

December 13, 2005 

Revision No. 

0 

Document No. 

SCA-TR-TASK1-0006 

Page No. 

27 of 158 

report and in some of the referenced material appears to be invaluable not only for evaluating 

doses for reactor re-entry personnel, but probably also for (1) personnel re-entering test areas 

after atmospheric tests, (2) drill-back and tunnel re-entry workers who entered within hours or 

days after underground tests, and (3) evaluation of doses from underground tests with inadvertent 

releases of radionuclides that exposed many personnel, notably the Baneberry test. 

The projected doses in NRDL 1968 are based on actual data from prior reactor tests. The report 

discusses doses from fine as well as large particles. These incorporated mainly short-lived 

fission products. The aim of the report was to estimate doses, with re-entry time and length of 

stay as the key safety variables that needed to be decided prior to the Phoebus 2A reactor test. 

Large particles, also called “coarse particles,” were defined as “those of diameters greater than 

12μ.” The dose from these particles would be due to exposure as they fell out and due to 

resuspension, with the latter assumed to be the only mode after 20 hours (NRDL 1968, pg. 21).1 

Using a resuspension factor of 4*10-6 m

-1, NRDL 1968 found the resuspension doses to be small 

compared with the early re-entry doses (NRDL 1968, pg. 38). 

In this context, lung doses, which are due to inhalation of fine particles, were evaluated to be 

rather small. Gonad doses from fine particle deposition were not small in several circumstances. 

Doses were also estimated from large particles to the GI tract and skin, and were found to be 

large in many cases. For the gonads, the dose would be from beta particles and photons 

emanating from deposited fine particles, whereas the beta component was expected to dominate 

skin and GI-tract doses. It is noteworthy that the beta dose to the GI tract was attributed to 

inhalation of large particles: 

Inhalation may lead to introduction of particles to the deep lung where they 

reside for relatively long times or to the gastrointestinal tract where they reside 

for shorter intervals. [NRDL 1968, pg. 1] 

And, 

Doses contributed by fine particles to the gastrointestinal tract are negligible with 

respect to those contributed by coarse particles. Dose estimates in this section 

will, therefore, be based on coarse particles alone. [NRDL 1968, pg. 15] 

Inadvertent direct ingestion of soil containing radioactive particles and ingestion of contaminated 

food are not discussed in NRDL 1968. Rather, ingestion of large particles after inhalation 

(presumably either through the nose or the mouth or both) appears to have been the main 

consideration. Similarly, skin doses were estimated as being due mainly to large particle 

deposition. 

1

 The analysis in NRDL assumes that particles of 50 microns or more settle out within 2 hours, and that 

particles of 12 microns take about 20 hours to settle (NRDL 1968, pg. 16). This assumption may be valid for reactor 

tests, but may not be valid for weapons tests. In the latter case, dust particles could remain suspended in the air for 

days after the test (see Warren 1945, for instance). Stafford Warren, the test safety director, did not provide particle 

sizes, and these are not given for the post-Trinity test survey. However, he noted that there was “still a tremendous 

quantity of radioactive dust-floating in the air” on July 21, 1945, in his memo to General Groves of that date. 
 

 

 

 

 

Effective Date: 

December 13, 2005 

Revision No. 

0 

Document No. 

SCA-TR-TASK1-0006 

Page No. 

28 of 158 

Table 2 shows skin and GI-tract doses due to large particle exposure, as estimated in NRDL 

1968 for the Phoebus 1B, EP-IV reactor test. It should be noted that these doses are estimated 

using a statistical approach by combining the probability of finding a particle in the GI tract or 

on the skin (small) and the dose per particle (large). A Poisson distribution was used to combine 

the two. SC&A has not investigated the details of the calculations or the raw data that went into 

the estimates, but the approach appears reasonable within the context of the data presented in 

NRDL 1968. Specifically, SC&A has not evaluated the linear dependence of large particle dose 

on wind speed assumed in the calculations. 

Table 2. Skin and Gastrointestinal-Tract Large Particle Beta Doses to Re-entry 

Workers, Phoebus 1B, EP-IV Test 

Location, deposition density Time of entry, 

hours1 Skin β dose (rad)3 GI-tract β dose (rad)3 

CP Area, 6 particles/100 ft2 16.50 418 709 

R-MAD, 5 particles/100 ft2 3.50 1,605 1,334 

R-MAD, 120 particles/100 ft2 12.91 10,625 16,290 

R-MAD, 1.5 particles/100 ft2 23.002 83.7 154 

A&E parking lots 1 particle/150 ft2 6.50 119 133 

A&E parking lots, 30 particles/100 ft2 12.50 2,750 4,140 

Source: NRDL 1968, Table B, pg. 49. 

Note 1: Converted from data and time to hours after the reactor test, which was at 1430 hours, February 23, 1967. 

Note 2: Value at 20 hours used in NRDL 1968, since that was the maximum time for the computer program. 

Note 3: Dose estimates in NRDL are proportional to large particle areal density and wind speed. The high doses 

estimated here are, in part, due to the high wind speed of 15 mph during the reactor test. 

It is evident that these doses depend heavily on (1) weather conditions (specifically wind speed), 

(2) particle size distributions, and (3) assumptions about ingestion of large particles as a result of 

inhalation in the case of GI-tract doses and particle deposition on skin for skin doses. SC&A 

notes that NRDL 1968 considers only deposition on 22% of the skin surface and ignores beta 

dose due to particles deposited on clothing. 

The NTS TBD contains essentially no guidance on dose reconstruction for reactor re-entry 

personnel. Table 5D-20 lists only current radionuclides of concern for the Nuclear Rocket 

Development Area (Area 25). This short list is inadequate for assessment of doses for personnel 

associated with reactor testing, and especially so for early re-entry personnel. The TBD is 

substantially incomplete in this regard. SC&A suggests that NIOSH evaluate the NRDL model 

and data, and consider the issue of large particle ingestion and skin deposition. Further, since the 

GI-tract doses are due to large particle ingestion, urinary analysis for mixed fission products is 

unlikely to be a satisfactory indicator of the dose. Fecal data that are accompanied by times of 

sampling and analysis may be helpful in providing some indication of the exposures via this 

pathway. SC&A has not reviewed claimant files to examine whether adequate data exist to 

perform such an analysis. 

NRDL 1968 provides time- and distance-related dose estimates for the gonads ranging from a 

low of a few millirad to a high of 2.78 rad, assuming that personnel were not allowed into the 
 

Effective Date: 

December 13, 2005 

Revision No. 

0 

Document No. 

SCA-TR-TASK1-0006 

Page No. 

29 of 158 

areas with the highest radiation fields less than 8 hours after the test (NRDL 1968, Table E, 

pg. 52). These figures indicate that NIOSH should also examine the issue of beta-gamma gonad 

dose for reactor tests, since the cumulative dose to certain personnel may be considerable. This 

issue will be of particular importance in the years prior to 1966, when no beta doses were 

recorded. 

NIOSH should also consider the dose implications of the above methods for other near-surface 

organs, notably the breast and thyroid. Finally, the magnitude of the doses and their dependence 

on test size and conditions, indicate that NIOSH should conduct a test-by-test estimate of the 

relevant organ doses, unless estimates that bound all reactor tests are developed and can be 

reasonably applied. 

As a final point with regard to this finding, when doses are in the hundreds of rad or more, the 

harm is expected to extend beyond stochastic risks of cancer to somatic harm. NRDL 68 

discusses the Krebs dose to the skin in this context: 

Dose rates from particles of different sizes were calculated at two depths in tissue 

using the NRDL TDD model. The two selected depths are: (1) 100 μ directly 

underneath the particle, i.e., in the germinal skin layer, and (2) the Krebs’ depth. 

The Krebs’ depth is defined as being anywhere along the periphery of a circular 

field of 4 mm radius 100 μ deep in skin tissue. The center of the field is directly 

beneath the particle on the skin. Krebs has shown that acute lesions to the skin 

develop if a dose greater than 1500 rads is accumulated at the Krebs’ depth. 

[NRDL 1968, pg. 21] 

The issue of how localized large doses due to coarse hot particles are to be handled in IREP 

inputs and estimates of the probability of causation needs to be addressed at least for those 

organs for which these are relevant, namely the organs near the surface of the skin and the GI 

tract. 

5.3 ISSUE 3: LARGE PARTICLE DOSES DURING NUCLEAR WEAPONS TESTS 

Finding 3: The TBD has not adequately considered large particle doses to personnel entering 

nuclear weapon test areas within hours or days of the test. Reactor test studies indicate that 

skin and GI-tract doses to early re-entry personnel may far exceed doses estimated via the fine 

particle inhalation or deposition pathway. 

The TBD does not discuss problems analogous to the ones discussed in Finding 2 for early reentry by personnel into reactor test areas that may affect dose estimates for personnel associated 

with atmospheric and underground weapons testing. In addition to the above considerations 

regarding doses from large hot particles incorporating mainly short-lived fission products, 

airborne large particles during atmospheric testing would be expected to contain short-lived 

activation products, notably the ones listed in Table 1 above. For instance, large particles with 

significant amounts of 24Na need to be evaluated. In the case of atmospheric testing, the 

resuspension of previously deposited large particles may be of considerable importance, in 

addition to the inhalation doses due to fine particles. 
Effective Date: 

December 13, 2005 

Revision No. 

0 

Document No. 

SCA-TR-TASK1-0006 

Page No. 

30 of 158 

Large particle doses may also be of considerable importance during accidental ventings of 

underground tests, notably the Baneberry test, when many personnel were exposed to the fallout 

cloud. According to the NTS TBD, none of the 86 personnel exposed received an “exposure that 

exceeded the guideline for radiation workers” (NTS TBD Vol. 5, pg. 69). NIOSH should reevaluate shallow doses and GI-tract doses, in light of the NRDL analysis of large particle 

exposures associated with the Baneburry test, as well as other underground tests that resulted in 

accidental ventings. 

Finally, the large particle issue may also be an issue for early drillback and other re-entry by 

personnel into underground test areas. SC&A has not evaluated this issue in light of the NRDL 

analysis, but it deserves screening calculations by NIOSH to determine the relevance and scope 

of the issue. 

5.4 ISSUE 4: INGESTION DUE TO ORO-NASAL BREATHING 

Finding 4: Ingestion of large particles due to oro-nasal breathing may increase GI-tract doses 

to workers who re-entered weapons and reactor testing areas shortly after the tests. 

SC&A has so far raised oro-nasal breathing issues in relation to inhalation doses. However, in 

the case of the NTS, ingestion of large particles by mouth breathers would be expected to be 

larger than that due to inhalation of large particles alone. NIOSH should examine the 

significance of this issue in light of the above considerations. SC&A emphasizes that the issue 

here does not relate to heavy or light work as such, but to ingestion of large, non-respirable 

particles at all levels of activity that may be enhanced due to oro-nasal breathing. 

5.5 ISSUE 5: ENVIRONMENTAL OCCUPATIONAL DOSE 

5.5.1 Overall Environmental Dose Finding 

Finding 5: Environmental occupational dose during weapons testing is not adequately 

addressed in the TBD. 

SC&A’s review of occupational environmental dose involved consideration mainly of Volume 4 

of the NTS TBD, but also of the Introduction to the TBD (Vol. 1) and the Site Description 

(Vol. 2). SC&A also reviewed some of the associated documentation. 

The environmental TBD includes internal doses to unmonitored workers from onsite releases to 

the air and from resuspension of contaminated soil, external doses from ambient radiation and 

releases of noble gases, and radon exposure to tunnel workers. Atmospheric testing from 1951– 

1963 is mentioned and some data are presented in the TBD. However, the focus of the TBD is 

on underground testing. In view of the data and conclusions that are presented for the 

atmospheric testing period and the pending revision of the NTS TBD, this SC&A review covers 

that period, but largely focuses on the methodology for exposures from 1963 onward. However, 

some comments on the pre-1963 period are included for NIOSH to consider as it addresses the 

atmospheric testing period. Further, covering the early period is important for non-weapons 
Effective Date: 

December 13, 2005 

Revision No. 

0 

Document No. 

SCA-TR-TASK1-0006 

Page No. 

31 of 158 

testing related issues, notably reactor testing. While the TBD addresses environmental dose 

issues only for unmonitored workers, SC&A has noted some issues that also affected monitored 

workers who spent significant amounts of time in outdoor contaminated areas. These include 

large particle doses to workers re-entering reactor and weapons test areas, and possibly large 

particle resuspension ingestion doses. 

5.5.2 Internal Occupational Environmental Dose 

Finding 6: Resuspension intake estimates are not scientifically defensible or claimant 

favorable due to a variety of factors. The doses estimated by using the procedures specified in 

the TBD may underestimate doses by more than an order of magnitude. 

The estimation of intakes and doses from deposited radionuclides is a complex problem, fraught 

with uncertainties, especially for unmonitored workers, and to a lesser extent, for monitored 

workers. SC&A has explored several crucial factors and parameters that are discussed in the 

TBD and that go into estimation of resuspension doses for unmonitored workers. SC&A has 

also indicated lines of analysis for monitored workers in this section, which are amplified and 

discussed in more detail in the sections on internal and external dose. The following subsections 

present the various sub-elements that comprise this finding. 

5.5.2.1 NTS soil contamination data and the TBD’s analysis of the data to derive air 

concentrations are inadequate. As a result, resuspension doses may be significantly 

underestimated. 

The TBD relies on McArthur 1991 as the basic reference for soil contamination at NTS, so far as 

long-lived radionuclides are concerned. These data are summarized in Table 2-8 (TBD Vol. 2, 

pg. 45). 

The contaminated areas that are listed in Table 2-8 represent only part of the entire NTS area. 

The total of column 2 is 1,300 km2 compared to the size of the entire NTS of 3,500 km2 . 

According to Figure 1 and Table 3 (at the end of this section), the contaminated areas represent 

just 38% of the entire NTS area. Figure 2 shows that a contaminated part of a given NTS area is 

not uniformly contaminated. In contrast, it is characterized by areas with hot spots of high soil 

activity. The purpose of the radionuclide inventory reports that are the source of the TBD 

calculations was to determine an overall inventory and its distribution. McArthur 1991, where 

the inventory and distribution data are summarized, states the following: 

The objective of the RIDP [Radionuclide Inventory and Distribution Program] 

was to estimate the distribution and total inventory of the important manmade 

radionuclides of NTS origin in the surface soil of NTS. [pg. 2] 

The TBD has not made a claimant-favorable evaluation of the available inventory and 

distribution data. Specifically, the TBD has used the total estimated inventory over an entire 

area for each listed radionuclide and divided by the area to determine the surface contamination 

to be used for estimating resuspension. This approach does not take the large variability of soil 

contamination levels into account. Consider Area 10 as an example. The average concentration 
Effective Date: 

December 13, 2005 

Revision No. 

0 

Document No. 

SCA-TR-TASK1-0006 

Page No. 

32 of 158 

of 137Cs indicated in Table A-2 of McArthur 1991 is about 1,930 nCi per m2, whereas there is an 

isopleth of 10,000 nCi per m2

, or about 5 times the average, for the same radionuclide 

documented in Figure 6 (pg. 17) of the same publication. The interior area of the 10,000 nCi 

per m

2

 isopleth is rather large. Hence, it is possible and even likely that considerably higher 

concentrations would be found in the form of hot spots of significant size within that isopleth. 

SC&A has not investigated the raw data, since the published summary in McArthur 1991 is 

clearly sufficient to show that the use of average data for area contamination is not claimant 

favorable, bearing in mind that there could be reasons for claimants to be preferentially located 

in the areas of higher contamination. 

Besides issues relating to the interpretation of the available data in the TBD, there are also 

deficiencies in the underlying data for soil contamination that are the basis for estimating 

resuspension dose. These issues are distinct from the choice of resuspension factors (also 

discussed below). 

5.5.2.2 Survey grid in the “affected areas” may not be adequate to detect hot spots. 

Most of the areas designated as “affected areas” had a ground zero within them for at least one 

test. These areas were surveyed as follows: 

The basic arrangement of measurement locations was a grid of points 400 or 

500 feet apart. In the early surveys, an irregular pattern of grid points was 

measured that reflected the isopleths of exposure rates derived from the aerial 

survey results. In later surveys, complete rectangular grids were measured to 

simplify the data analysis, though the grid spacing was often increased in areas of 

relatively low concentration. [McArthur 1991, pg. 7] 

Hence, the grid, when regular, consisted of squares, each of which had an area of about 

200,000 square feet, or almost 20,000 square meters. Many surveys used a grid that was even 

more crude. For comparison, in its 1992 decommissioning guidelines (NUREG/CR-5849), the 

Nuclear Regulatory Commission suggested a grid consisting of 10 x 10 meter squares, or about 

100 m2

 each for outdoor contaminated areas defined as “affected areas” (NRC 1992, pg. 4-12). 

Such a grid is about 200 times more refined than the one used for the NTS surveys of the 

affected areas. 

SC&A recognizes, of course, that the area to be surveyed at NTS is very large, and that the 

guidance document cited above was prepared for decommissioning surveys. By the same token, 

such guidance can serve as an approximate guide to the accuracy of the data for purposes of dose 

reconstruction. The NRC recommends that surveys should provide 100% coverage of affected 

areas. The area surveyed by the in-situ measurements was likely to have been a small fraction of 

this guideline. One might expect that a high-purity germanium detector would effectively ‘see’ 

contamination in the top few centimeters out to a radius of around 50 feet, depending on the 

shielding arrangements employed. This means that an area of ~700 m2

 would have been 

surveyed, which is only about 3.5% of area of a grid square. The coverage would be lower for 

larger grid spacing. 
Effective Date: 

December 13, 2005 

Revision No. 

0 

Document No. 

SCA-TR-TASK1-0006 

Page No. 

33 of 158 

SC&A recognizes that the aerial coverage could have been better than that covered by the in-situ 

measurements. However, these surveys were carried out with a NaI detector with a relatively 

low sensitivity. This is unlikely to have picked up hot spots that might have been missed by the 

in-situ surveys. NIOSH should examine both the aerial and in-situ raw data in order to make a 

more refined assessment of the issue of hot spots. Such an assessment is needed for a dose 

reconstruction approach that is demonstrably claimant favorable. 

The use of survey data with a crude grid for dose reconstruction at NTS may be particularly 

problematic due to the possibility of unrecognized hot spots created during the atmospheric 

testing period. 

5.5.2.3 Measurements of soil inventory of radionuclides in areas thought to be relatively 

unaffected may not be adequate to identify all significant hot spots 

SC&A is in broad agreement with the process described in McArthur 1991 to identify the areas 

most likely to be contaminated: 

The portions of the NTS covered by the in situ surveys.... ... include all the GZs of 

above-ground nuclear tests, the GZs of underground nuclear tests where 

significant amounts of radioactivity reached the surface, safety-shot sites, the 

rocket test facilities in Area 25, and other places where aerial surveys showed 

elevated levels of radioactivity. For the most part, those portions of the NTS not 

covered by in situ surveys were known (from aerial surveys, ground-based 

monitoring, and the history of NTS operations) to have no contamination from 

NTS activities. [McArthur 1991, pp. 4–5] 

SC&A has therefore listed this approach as one of the strengths of the NTS TBD. However, 

SC&A has some concerns regarding the identification of all significant hot spots. Specifically, 

hot spots in areas some distance from ground zero might be expected from atmospheric testing in 

a manner that is not easily susceptible to estimation. A similar comment would apply to 

underground tests that resulted in significant venting. 

Moreover, confirmatory sampling in areas designated as unaffected does not appear to have been 

done in a manner that would be likely to detect previously unidentified hot spots. Specifically, 

“only a few measurements were made in background areas” (McArthur 1991, pg. 3). Moreover, 

in areas that had no ground zeros, which would constitute the bulk of the areas designated as 

unaffected, “measurements were made primarily along roads” (McArthur 1991, pg. 7). The 

NRC guidelines suggest that unaffected areas should be “uniformly scanned” (NRC 1992, 

pg. 4.16), and that soil sample locations should be “randomly selected.” This procedure does not 

appear to have been followed in the surveys of the unaffected areas. 

The TBD does not discuss any procedure by which the available raw data could be analyzed in 

order to ensure that the occupational environmental dose estimation procedure based on soil 

inventory and distribution estimates is scientifically reliable and consistently claimant favorable. 

In fact, the TBD does not have any analysis of those raw data at all. 
Effective Date: 

December 13, 2005 

Revision No. 

0 

Document No. 

SCA-TR-TASK1-0006 

Page No. 

34 of 158 

5.5.2.4 The resuspension factor used in the TBD is questionable 

The resuspension factor was based on the model presented by Anspaugh et al. (2002). The longterm equilibrium value of 1.3 x 10-9 m-1 was selected “because the vast majority of radionuclides 

in surface soil were deposited from atmospheric testing that stopped in 1962, and because it is 

reasonable to assume that unmonitored employees would not be likely to be exposed to freshly 

deposited radionuclides.” 

The TBD provides no analysis for the various periods of activities and classes of employees to 

validate the assumption that “unmonitored employees would not be likely to be exposed to 

freshly deposited radionuclides.” This assumption may not be correct for all periods. 

Specifically, SC&A has two concerns regarding this assumption. There was no internal dose 

monitoring until late 1955, and monitoring was scant and selective after that into the 1960s. 

Since Rad-Safe and other personnel did enter forward areas from the start of the testing program, 

the assumption that unmonitored employees were not at risk of exposure appears to be too 

expansive and needs, at least, to be narrowed to specific job types and specific periods. As 

another example, site expert interviews indicate that “laborers” were used in the initial years of 

atmospheric testing to perform certain tasks, like equipment retrieval, soon after test shots. They 

may not even have had external monitoring. For entry into contaminated areas within 100 days 

of a test shot, the TBD acknowledges that the resuspension factors could have been orders of 

magnitude higher: 

As discussed in Anspaugh (2002), the uncertainty suggested in equation 4-3 is 

plus or minus one order of magnitude. This is a large uncertainty, but it is based 

on actual measurements that suggest the very complex nature and 

unpredictability of the resuspension process. In addition, the time-dependence of 

the resuspension factor suggested by equation 4-3 covers a range of almost four 

orders of magnitude. Therefore, if an unmonitored employee was exposed to 

freshly deposited fallout, the intake values in Tables 4.2.2-2 and 4.2.2-3 could 

represent significant underestimates of the actual intake. However, because of 

the rapid decrease in the resuspension factor with time, the likelihood of exposure 

of this type for periods greater than a few days would be very small. In addition, 

a claimant-favorable factor of 10 has been applied to the resuspension factor to 

minimize the likelihood that airborne concentrations would be underestimated. In 

addition, the number of unmonitored employees likely to have been inadvertently 

exposed to fresh fallout would be small. [TBD Vol. 4, pp. 34–35] 

In fact, Anspaugh 2002 does not recommend the use of resuspension coefficients for estimating 

intakes at times long after the initial radionuclide deposition. Rather, the dust loading approach 

is preferred, unless suitable air concentration data are available: 

The resuspension-factor model has been widely used to predict the concentration 

of resuspended contaminant at times early after the initial deposition. The massloading model has generally been preferred for times long after the deposition. 

However, at times long after deposition and in situations where there is a real 

and legitimate concern about resuspension, it is always preferable to rely on 
 

Effective Date: 

December 13, 2005 

Revision No. 

0 

Document No. 

SCA-TR-TASK1-0006 

Page No. 

35 of 158 

actual measurements that are performed over long time periods. [Anspaugh 

2002, pg. 676.] 

In view of the above, reliance on Anspaugh 2002 for estimating a resuspension factor for times 

long after the deposition is inappropriate, as is the use of such a factor for long-term intake 

estimation. 

The TBD makes no attempt to describe which workers were likely to have entered within a few 

days. Further, entry for short periods of time, such as a few days within several days of the test, 

would be likely to produce doses in excess of those that would be estimated using the suggested 

resuspension factor of 1.3 x 10-9 per meter. For instance, accepting the values in Figure 4.2.2-1 

of the TBD (Vol. 4, pg. 32) as valid, entry within a month would imply a resuspension factor of 

~1 x 10-6 per meter, which is about 770 times larger than the mean value assumed in the TBD. 

Entry within a few days would imply resuspension factors thousands of times larger than those 

assumed in the TBD. 

The approach suggested for entry after long periods is not demonstrably claimant favorable. The 

TBD states that “a claimant-favorable factor of 10 has been applied to the resuspension factor to 

minimize the likelihood that airborne concentrations would be underestimated.” However, in 

view of the above and the analysis below, this does not ensure a claimant-favorable procedure in 

the absence of additional data for validating the claimant favorability of the choice. 

It is not clear that the particulate sampling data at NTS can meet the test of suitability for use in 

determining resuspension factors for the purpose of claimant-favorable dose reconstruction. 

Specifically, the measurement of respirable particulates in the 5 to 10 micron range may be 

underestimated to a considerable extent by certain types of air samplers. Extensive wind tunnel 

research by Los Alamos scientists has shown that some sampler designs have efficiencies of only 

20% to 25% for 5 to 10 micron particles at high wind speeds (12.5 m/sec or more), whereas 

others have efficiencies in the 50% to 100% range (Rodgers et al. 2000). The TBD contains no 

analysis of the underestimation of the resuspension factor and of the uncertainties in it that may 

be caused by the type of sampler that was used. 

Further, the air sampling data are area measurements. The problem of relating these area 

measurements to individual worker intake is complex and difficult. While the assumption of a 

2,000 hour per year presence in the contaminated areas may be assumed to be generally claimant 

favorable, it remains to be demonstrated that such an assumption can offset the factors that could 

contribute to significant underestimation of environmental dose at NTS. 

Finally, future revisions of the TBD should consider the comments on resuspension factors 

pertinent to the NTS presented in A Review of the Dose Reconstruction program of the Defense 

Threat Reduction Agency, prepared by the NAS. Of particular relevance to the reconstruction of 

internal dose associated with resuspension processes are comment Nos. 6 and 7 on pages 193 and 

207 of the NAS report. These comments address the importance of addressing the inhalation 

doses associated with the resuspension of aged fallout, and the finding that resuspension factors 

associated with the blast wave could be over 100-fold greater than the default resuspension 

factors of 10-5 per meter employed in the program. 
Effective Date: 

December 13, 2005 

Revision No. 

0 

Document No. 

SCA-TR-TASK1-0006 

Page No. 

36 of 158 

5.5.2.5 The TBD method to assign resuspension doses to workers where the location is not 

known may underestimate the exposure. 

In cases where the exact location is not known, the TBD recommends the use of site average 

values (NTS TBD Vol. 4, pg. 33). This may underestimate the exposure by a considerable 

amount, given the differences between locations and the differences between the average and 

maximum intakes (NTS TBD Vol. 4, Tables 4.2.2-2 and 4.2.2-3). For example, if a claimant 

was working in Area 11, but this was not properly recorded, the use of site average data for that 

site would result in a resuspension dose that is a factor of 4 lower than in the case where records 

exist. The differences between areas are even larger. The overall underestimation could be an 

order of magnitude or even much more. Since the lack of proper records should not result in a 

disadvantage for the claimant, it would be more appropriate to use the values for the area with 

the maximum inferred air concentration. If the area number is not known, the largest value 

should be used, consistent with other employee job-type data. 

5.5.2.6 The TBD does not evaluate resuspension exposure for monitored workers. 

Adjustments to radionuclide intake may be necessary for some monitored workers. 

Available evidence indicates that after 1957, entry into contaminated areas was restricted to 

workers who were monitored (Attachment 4). However several factors, discussed in more detail 

elsewhere in this review, indicate that an explicit evaluation of working conditions is necessary 

to ensure that dose estimates due to resuspended radionuclides are claimant favorable. The 

following factors need to be taken into account: 

• 	 Bioassay done every few months would not detect the presence of relatively short-lived 

radionuclides, such as 24Na and 239Np. Workers entering contaminated areas within days 

of a detonation of an atmospheric test or a test that vented may have been exposed to a 

variety of short-lived radionuclides (see Finding 3 above). The TBD does not specify a 

procedure for evaluating exposures to such radionuclides for monitored workers. 

• 	 Time of entry after the test and the specific type of test are both important in assessing 

the radionuclide list, as well as the potential for large, hot particle ingestion or shallow 

dose. The TBD does not specify procedures for best estimate doses or maximizing 

procedures in such cases. 

• 	 Resuspension of plutonium in safety test areas due to atmospheric weapon testing needs 

to be evaluated for its importance, especially to early re-entry workers. 
Effective Date: 

December 13, 2005 

Revision No. 

0 

Document No. 

SCA-TR-TASK1-0006 

Page No. 

37 of 158 

5.5.2.7 Some solubility assumptions for resuspended radionuclides are not scientifically 

appropriate 

The TBD recommends that Type S solubility be used for all radionuclides deposited in the soil, 

except for plutonium for which Type M or Type S is recommended because of dispersal of 

plutonium in safety tests. While the implication of the assumption is that particles in nuclear test 

fallout are oxides and this is correct, the other implicit assumption that oxides in fallout are all 

Type S is not correct. For instance, cesium oxide may be assumed to be Type F, since it belongs 

to the alkali metals group. The 137Cs dose conversion factor for the kidneys for Type F is about 

50% larger than that for Type S. There may also be additional considerations in the specific 

instance of 137Cs released from a high-temperature environment. Studies of this issue in 

connection with the Chernobyl accident largely confirm Type F behavior, but also indicate that 

some fraction of 137Cs may be retained for much longer—months or years. NIOSH needs to reexamine the blanket assumption that an assumption of Type S for all resuspended radionuclides 

except plutonium is scientifically reasonable and claimant favorable. 

5.5.2.8 A dust loading approach may be more appropriate than using resuspension factors 

for estimating resuspension intakes. 

Both the dust loading and resuspension factor approaches can be useful for estimating 

radionuclide concentrations in air arising from the resuspension of ground deposits. However, 

their contexts of applicability are substantially different. The resuspension factor approach is 

most applicable to recent deposits arising from atmospheric deposition. In these circumstances, 

the radionuclide is deposited heterogeneously at or close to the soil surface, and it is difficult to 

define a meaningful concentration on a mass basis appropriate to the soil particles that are 

susceptible to resuspension. In these circumstances, an empirically determined resuspension 

factor may be used. This relates the concentration in air (Bq m-3) to the areal concentration on 

the ground (Bq m-2). Thus, it has dimensions of [L]-1 and typical units of m-1 . 

The resuspension factor approach has the advantage that it relates directly to the deposit per unit 

area, so the issue of depth averaging is avoided. However, a consequence of this is that the 

resuspension factor depends on the time after deposition, due both to the development of a 

vertical soil profile and (possibly) to a change in the degree to which the deposited radionuclide 

is associated with different soil fractions. In principle, these changes should depend on factors 

such as soil type, vegetation cover, and climatic conditions. However, in practice, a single twocomponent curve is often adopted as a simplification. 

The resuspension factor approach has the other characteristic that it implicitly includes the 

effects of contributions to the air concentration from areas upwind of the point of measurement, 

i.e., it is not a local measure. This can lead to enhanced values of the resuspension factor when 

there is a strong gradient of decreasing soil deposition downwind. 

The dependence of the resuspension factor with time after deposition is well illustrated by the 

formula given in Equation 4-3 of ORAUT-TKBS-0008-4. This is: 

SF = [1*10-5exp(-0.07t) + 6*10-9exp(-0.003t) + 1*10-9]×10±1

 m-1 
 

 

 

Effective Date: 

December 13, 2005 

Revision No. 

0 

Document No. 

SCA-TR-TASK1-0006 

Page No. 

38 of 158 

where t is the time after deposition in days. 

This formulation permits a time-averaged resuspension factor to be calculated as: 

∫SFdt/∫dt 

Values of this quantity computed over the interval [0, T] are shown in the following table and 

graph for different values of T. Note that from Equation 4-3, these values are uncertain by a 

factor of 10±1 . Thus, for exposure over extended periods after deposition, a resuspension factor 

in the range 1*10-9 to 1*10-5 m-1 seems plausible. 

Table 3: Time-Averaged Resuspension Coefficients 

T (d) Time-averaged 

Value (m-1) T (d) Time-averaged 

Value (m-1) T (d) Time-averaged Value (m-1) 

1 9.67E-06 160 8.99E-07 2000 7.34E-08 

3 9.03E-06 180 7.99E-07 3000 4.93E-08 

10 7.20E-06 200 7.20E-07 4000 3.72E-08 

20 5.39E-06 250 5.77E-07 5000 3.00E-08 

30 4.19E-06 300 4.81E-07 6000 2.51E-08 

40 3.36E-06 350 4.13E-07 7000 2.17E-08 

50 2.78E-06 400 3.62E-07 8000 1.91E-08 

60 2.35E-06 450 3.22E-07 9000 1.71E-08 

70 2.03E-06 500 2.90E-07 10000 1.55E-08 

80 1.79E-06 600 2.42E-07 15000 1.07E-08 

90 1.59E-06 700 2.08E-07 20000 8.24E-09 

100 1.43E-06 800 1.82E-07 25000 6.79E-09 

120 1.20E-06 900 1.62E-07 

140 1.03E-06 1000 1.46E-07 

In the dust loading approach, the radionuclide concentration in air is calculated as the product of 

the radionuclide concentration in surface soil (expressed on a dry mass basis and averaged over 

some specified depth), the dust load in air derived from local soil (not necessarily identical to the 

total dust load in air), and an enhancement factor reflecting the degree to which the resuspended 

dust is enhanced (or depleted) in the radionuclide of interest relative to the local soil.2 The 

enhancement factor depends on the soil texture, as radionuclides tend to be preferentially 

adsorbed to the smallest soil particles, and these are preferentially resuspended. Thus, the 

enhancement factor is largest for sandy soils (as these have the smallest fraction of small 

particles) and smallest for clay soils. 

Dust loads in air are very variable, ranging from <0.1 mg m-3 up to ~100 mg m-3 during 

disturbance by mechanical action. The soil depth from which resuspension occurs is not well 

defined, but it is plausible to take it as about 1 mm. As surface soil has a dry bulk density of 

around 103

 kg m-3, the total mass of soil available for resuspension is around 1 kg m-2 . Applying 

2

 See discussion of enhancement factors provided in Algorithm for Calculating an Availability Factor for 

the Inhalation of Radioactive and Chemical Materials, EGG-2279, prepared by Envirosphere Co., New York, NY 

for the U.S. Department of Energy under Contract No. DE-ACO7-76IDO1570, February 1984. 
Effective Date: 

December 13, 2005 

Revision No. 

0 

Document No. 

SCA-TR-TASK1-0006 

Page No. 

39 of 158 

a resuspension factor in the range 1*10-9 to 1*10-5 m-1 (see above), the calculated dust load in air 

is in the range 0.001 to 10 mg m-3 . Thus, there is an overlap in the ranges calculated by the two 

methods, but the dust loading approach tends to give rather larger values. 

Since the dust loading approach is more applicable at long times when a soil profile has 

developed, is more readily related to physical processes, and typically yields higher 

concentrations of radionuclides in air (and hence is claimant favorable), it is preferred for 

assessment purposes. For instance, in a recent international study on long-term impact of 

contaminant releases from waste disposal, the French nuclear waste agency, ANDRA, noted the 

following: 

Particulate resuspension from terrestrial surfaces is caused by wind erosion of 

soil, vehicle traffic on dusty roads, industrial and agricultural activities and 

combustion of biomass for fuel or land-clearance. The effects of these processes 

are poorly understood. Even the science of wind erosion, which has been studied 

extensively, does not permit prediction of the upwardly directed flux of soil 

particles resuspended by wind action. Thus, the conventional flux dispersion 

methodology must be abandoned and resuspension and subsequent deposition of 

dust or soil onto plants and soil surfaces is generally computed using a massloading approach. This approach treats all the particulate resuspension 

processes simultaneously. [BIOPROTA 2005, pg. 6] 

In summary, SC&A recommends that, in the context of estimating environmental internal 

occupational exposures at NTS at times more than a few weeks after deposition, that NIOSH use 

a dust loading approach, with dust values chosen in an appropriately claimant-favorable manner. 

5.5.2.9 Conclusions in the TBD regarding resuspension intake estimates and their 

implications for dose estimates need to be reconsidered. 

The TBD recommends that the values in Table 4.2.2-3 be used for resuspension intakes for 

monitored workers. The values in this table are not claimant favorable and do not represent a 

full exploration of the uncertainties in intakes of radionuclides by unmonitored workers. The 

various factors that need to be considered and included in claimant-favorable ways before the 

estimates of intakes could be considered scientifically defensible and claimant favorable are as 

follows: 

• 	 The radionuclide concentrations at or near ground zero areas are likely to be much higher 

than the average for affected areas, and some workers who were involved in clean-up 

work and equipment retrieval would be more likely to go to such areas. The choice of 

values for areal radionuclide density needs to be made more claimant favorable. 

• 	 The general assumption that unmonitored workers were not at risk needs to be reexamined for some job types and time periods. 

• 	 Early entry into contaminated areas (less than 100 days after the shot) should be 

evaluated for some groups of workers, including unmonitored workers. This evaluation 
Effective Date: 

December 13, 2005 

Revision No. 

0 

Document No. 

SCA-TR-TASK1-0006 

Page No. 

40 of 158 

should include consideration of the resuspension factor as well as the radionuclide list to 

be used in assessing intake. 

• 	 The raw data from which areal radionuclide densities are estimated need to be analyzed 

to establish uncertainties created by sampling procedures that use a grid that is either too 

crude or non-representative. Such an examination may yield insights into how claimantfavorable values for areal radionuclide density can be established in light of relatively 

sparse survey data, especially in some areas. 

• 	 Activation products need to be factored in and their solubilities need to be explicitly 

considered. 

• 	 Large-particle-related doses to re-entry workers and other time-specific issues need to be 

developed in order to ensure scientifically sound and claimant-favorable dose estimates. 

• 	 There are a number of parameters involved in the estimation of mean and 95th percentile 

values for the resuspension factor that have not been taken into account. These include 

sampler underestimation of 5 to 10 micron particles at high wind speeds, the likelihood 

that in some time periods unmonitored workers did enter areas with high contamination 

soon after test shots (in the early period to 1957), and uncertainties in the time of entry of 

workers into the contaminated areas. 

• 	 The choice of Type S solubility for some radionuclides is neither scientifically defensible 

nor claimant favorable. The choice of Type F solubility of cesium oxide, for instance, is 

a reasonable one scientifically, for the most part (see above), and it results in a higher 

dose to some organs than an assumption of Type S solubility (e.g., kidneys). The more 

claimant-favorable value should be used. 

In summary, the estimates of intakes of radionuclides recommended in the TBD (Vol. 4, 

Table 4.2.2-3, pg. 33) due to resuspension could be too low by one to several orders of 

magnitude. In addition, unfavorable solubility assumptions in some cases would lower the doses 

for any given assumed intake. A considerable amount of scientific, statistical, and analytical 

work remains to be done before resuspension doses could be said to be scientifically defensible 

and claimant favorable. SC&A recommends that NIOSH use the dust loading approach for 

estimating internal intakes, since it is more scientifically defensible and claimant favorable for 

times more than a few weeks after radionuclide deposition. 

5.5.3 External Occupational Environmental Dose 

5.5.3.1 Overall Finding Regarding Occupational External Environmental Dose 

Finding 7: Occupational external ambient radiation doses need to be re-examined with 

explicit consideration given to the time period of testing. 

The TBD provides data for ambient external gamma radiation at different NTS areas that are 

listed in Table 4.3.1-2. The data covers the years 1967 to 2001. However, there are no data for 
Effective Date: 

December 13, 2005 

Revision No. 

0 

Document No. 

SCA-TR-TASK1-0006 

Page No. 

41 of 158 

the years 1968 through 1976 (inclusive). If the area is known in which a claimant has worked, 

the data listed for the area should be used in the dose reconstruction. According to the TBD, if 

the work area is not known, the maximum value should be selected. For 1963 to 1966, the 

maximum value reported for 1967 that was measured at Area 3 (318 mrem yr--1) should be 

assigned. The TBD states on page 40 that to do so is “reasonable and probably claimant 

favorable” because “it is likely that the elevated ambient radiation peaked in the early 1960s near 

the end of above-ground testing.” The TBD does not specify any approach to reconstructing the 

external environmental dose for the period 1968 to 1976. 

This finding consists of a number of sub-elements that focus on the following issues: 

• 	 Are the data in Table 4.3.1-2 representative for a particular area in question? 

• 	 Is it claimant favorable to use the Area 3 value for 1967 for the time period 1963 to 

1966? 

• 	 Can the data in the TBD be used to estimate occupational external environmental dose for 

the period prior to 1962? 

• 	 What are the issues relating to the 1968–1976 period for which there are no data in Table 

4.3.1-2? 

5.5.3.2 Representativeness of data for a given area needs to be further evaluated. 

The external gamma dose rates after the end of above-ground testing vary by area and within a 

given area. Two contributors to the external dose rate are natural background and global fallout, 

but their variability from area to area is probably small. The area-to-area variability due to NTS 

operations can be attributed to deposition from atmospheric testing, venting of underground tests, 

and other sources of radioactivity deposition (or re-deposition). Figure 3 indicates that the 

locations of the tests cover a large geographic area. In contrast to this, gamma dose rates were 

usually monitored at one location in a given area (Figure 4). Figure 5 indicates that the locations 

of the NTS ionization chambers were not in the most contaminated area. In addition, short-term 

exposures from cratering events, such as SCHOONER, were unlikely to be covered by the sparse 

network that the TBD relies on. This is illustrated by the fallout map for test SCHOONER in 

December of 1968 (Figure 6). The test was detonated in Area 19, but the closest locations with 

gamma dose rate data are Areas 12 and 18. It does not appear that the monitoring locations were 

in the fallout path. 

The variability of the external dose is large (Figure 7) and is, in part, explained by NTS tests. In 

addition, the measured external dose is strongly correlated with the beta activity in air, as shown 

in Figure 8. The variability in soil contamination has resulted in a variability of airborne 

radioactivity, and probably external gamma dose rates as well. It is, therefore, possible that a 

person who was present in a given area was exposed to higher external doses than those reported 

in the TBD on the basis of a single location. Therefore, it has not been demonstrated by ORAU 

that the sampled location is either representative or claimant favorable. 
Effective Date: 

December 13, 2005 

Revision No. 

0 

Document No. 

SCA-TR-TASK1-0006 

Page No. 

42 of 158 

5.5.3.3 It is unlikely that assigning 1967 data for the time period 1963–1966 is claimant 

favorable. 

The lack of external gamma dose data at NTS prior to 1967 is puzzling. It is unlikely that the 

reported dose for Area 3 in 1967 is claimant favorable for the following reasons: 

• 	 There were no underground tests in 1967 that resulted in measurable offsite fallout. In 

contrast to this, underground test PIN STRIPE on April 25, 1966, resulted in measurable 

offsite fallout (http://www2.nci.nih.gov/I131/intros/BK0.html). 

• 	 The dose measured for Area 3 is unlikely to have been the largest onsite dose at NTS, 

given the sparse network and the lack of representative sampling. 

• 	 Shorter-lived radionuclides like 134Cs, 141Ce, and 144Ce would have decayed substantially 

or nearly completely between 1963 and 1967, so that earlier external doses can be 

expected to be higher. 

5.5.3.4 Data for 1968 through 1976 are missing. The TBD has not specified an approach to 

estimating external environmental dose for these years. 

The NTS TBD states that no external environmental measurements were reported between 1968 

and 1976 (NTS TBD Vol. 4, pg. 35). It is proposed that maximum 1967 data be used for the 

years 1968–1976. However, it is not clear that this is claimant favorable, as claimed in the NTS 

TBD (Vol. 4, pp. 36–40). SC&A notes that there were no unplanned large venting events in 

1967, but that was not the case for the period 1968–1970. The Baneberry test in December 1970 

was the last large unplanned venting. The TBD has not specified any approach to estimating 

external environmental dose during those years. Significant deposition of radionuclides from 

ventings in the 1968–1970 period may have caused external environmental doses during that 

time, and possibly for a couple of years after that, to be higher than the measured values in 1967. 

A test-specific analysis should be carried out to develop claimant-favorable assumptions for the 

period of missing data. From the description in the introduction to Section 4.3 (pg. 35) and 

associated tables on pages 37 to 39 in Vol. 4 of the NTS TBD, it appears that NIOSH has not 

looked beyond the annual environmental reports to locate the missing data, but just filled in the 

gap as noted above. 

5.5.3.5 Pre-1963 period external environmental dose estimation procedure is not addressed 

in the TBD. 

The TBD does not discuss estimation of external environmental doses during the period of 

atmospheric testing (1951–1962). There are several issues to be considered in this context for 

unmonitored workers: 

• 	 Entry of unmonitored workers into contaminated areas, notably in the period up to and 

including 1957 

• 	 Time of entry of workers into contaminated areas 
 

Effective Date: 

December 13, 2005 

Revision No. 

0 

Document No. 

SCA-TR-TASK1-0006 

Page No. 

43 of 158 

• 	 Activation products in the soil with high external radiation potential—and the times at 

which these are important 

5.5.3.6 External environmental dose estimations for monitored workers need to be more 

comprehensively evaluated. 

The TBD does not discuss factors affecting external environmental dose for monitored workers. 

This omission rests on the implicit assumption that the dose recorded on the film badge was the 

dose experienced by the organ for which the dose reconstruction is being done, and that the data 

from the monitoring and radionuclide lists in the TBD are sufficient for splitting the recorded 

external dose into the three energy ranges that IREP requires for estimation of probability of 

causation. SC&A has several concerns about these assumptions. The following factors need to 

be addressed and correction factors developed, as necessary, so that the recorded external dose 

can be modified in a suitable way that is both scientifically defensible and claimant favorable for 

the purpose of estimating organ dose. 

• 	 The organ for which doses are being estimated relative to the position of the external 

radiation source—that is organs closer to the ground will tend to get a larger dose than 

those farther away—needs to be determined, so that an organ-specific external dose 

estimation procedure can be developed. SC&A notes that NIOSH developed correction 

factors for recorded dose for lower torso organs as part of its consideration of issues 

related to development of dose reconstruction for workers at the Mallinckrodt site in St. 

Louis (SC&A 2005b). Similar considerations apply in the case of external environmental 

dose at NTS, since the source of the radiation is located on the ground, but the film badge 

or TLD is normally worn on the pocket or collar. 

• 	 Two other correction factors for external dose are also necessary; (1) angle of incidence 

of the gamma radiation onto the film badge when it is not normal to the badge, and 

(2) the dose conversion factor. Both these factors are discussed in SC&A 2005a, SC&A 

2005c, and SC&A’s Task 3 report, SC&A 2005d. 

• 	 The time of entry into the contaminated zone is important, because the radionuclides 

present, and therefore, the photon energy spectrum that characterizes residual radiation, 

are time dependent. 

• 	 The TBD needs to investigate the possibility that workers sometimes did not wear their 

badges when the quarterly dose was near the 3-rem limit or above it, because they were 

sent to lower paying jobs or were laid off from their jobs for the rest of the quarter (see 

Section 7 below). 
Effective Date: 

December 13, 2005 

Revision No. 

0 

Document No. 

SCA-TR-TASK1-0006 

Page No. 

44 of 158 

5.5.3.7 Conclusions regarding external environmental dose for unmonitored and monitored 

workers need to be evaluated further. 

(1) The TBD has not demonstrated that the reported gamma doses are claimant favorable for 

a given area in a given year. It is unlikely that it is claimant favorable to assign 1967 data 

for the time period 1963–1966. 

(2) No method has been developed in the TBD to assess environmental external doses for the 

atmospheric testing period 1951–1962. 

(3) The factors relating to external environmental dose geometry for monitored workers have 

not been considered. 

(4) It may be very difficult to make best estimates of external environmental dose for 

unmonitored workers, given the uncertainties. A set of assumptions that would 

systematically give claimants the benefit of the doubt for the various sources of 

uncertainty remains to be developed. 

(5) There are some issues regarding external environmental dose estimation for monitored 

workers that remain to be addressed. Correction factors to resolve issues relating to 

geometry of exposure and time of entry need to be developed to demonstrate that the 

dose estimates are claimant favorable for the periods when monitored workers’ duties led 

them to spend a significant proportion of their time in outdoor contaminated areas or 

some time in such areas shortly after tests. Off-normal practices also need to be taken 

into account. 

5.5.4 Radon Dose 

Finding 8: Radon exposure in tunnels needs to be more thoroughly evaluated. 

The TBD recommends using the data in Table 4.4.1-1 for 222Rn exposures for miners and tunnel 

workers. For example, for pre-1984 exposure in the G-Tunnel, the radon daughter concentration 

(RDC) for alternating ventilation is calculated to be 0.13 WL, based on data reported by Favor 

1987. Table 3 of the referenced document contains the results of measurements that were 

actually taken in July 1984. The calculations in the TBD are based on the results of radon 

daughter grab samples, rather than on integrated samples. The comparison of the data indicates 

that in two out of three measurements, the integrated sample concentrations were a factor of 1.5 

and 1.6 larger than the grab sample (see Table 5). 

The TBD methodology for P-Tunnel and N-Tunnel measurements was to determine the average 

of the maximum values for sampled locations, whereby non-detected values are ignored. SC&A 

suggests that NIOSH should apply the same method to the G-Tunnel as well. The resulting RDC 

concentration for alternating ventilation would be 0.16 WL, or 1.92 WLM per year (based on 

170 hours of exposure per month for 12 months). 
Effective Date: 

December 13, 2005 

Revision No. 

0 

Document No. 

SCA-TR-TASK1-0006 

Page No. 

45 of 158 

Further, the above calculations are based on the assumption that the G-Tunnel ventilation was 

equivalent to the one during sampling, i.e., one of two fans turned off on alternate evenings. 

There were no records available to verify this assumption. NIOSH should investigate the issue 

of tunnel ventilation further. 

Another issue is the assignment of radon exposures in cases where the underground work 

location is not known. The TBD recommends using a level of 0.05 WL for all time periods, a 

value that actually represents the maximum level for 1984 onwards. It would be more 

appropriate and claimant favorable to assign the G-Tunnel value of 0.16 WL for exposures prior 

to 1984, if the underground work location is not known. 

The TBD does not discuss radon doses experienced by workers in the Gravel Gerties. In view of 

the possibility of significant respiratory tract radon doses, NIOSH should explicitly consider this 

issue in the NTS TBD or another appropriate TBD (depending on where the workers in these 

facilities came from). 

Finding 9: Accuracy of HTO sampling is questionable. 

The TBD summarizes HTO atmospheric concentrations in Table 4.2.1.2.1-1 on page 14. The 

efficiency of silica gel to capture water at low humidity is poor, as determined at Los Alamos. 

There, the amount of water collected in the dry season was less than a quarter of the amount 

expected from measured humidity levels (Eberhardt 1999). Since the environment at NTS is 

even drier than at Los Alamos, a correction factor needs to be developed for this loss of 

efficiency in low humidity. Ideally, the correction factor should be dependent on the season. 

However, in the context of dose reconstruction, NIOSH might consider developing a single yearround, claimant-favorable correction factor. 

The NTS site environmental reports do not appear to have corrected for this. If Los Alamos 

values are used, the reported data may have to be adjusted by a factor of ~4. Given the drier 

climate, the correction could be higher. SC&A has not done a detailed evaluation of the 

correction factor that would be suitable for the climate at NTS. SC&A notes that a suitable 

correction factor may result in HTO dose estimates of up to 8 or 10 mrem yr-1, rather than less 

than 2 mrem per year estimated in the TBD (Vol. 4, pg. 12). 

The TBD does not provide any reference or other scientific basis for the stated ratio of a factor of 

2 between the mean and 95th percentile values. As noted above, just one factor that was not 

considered, humidity, could lead to an error of a factor of 4 or more. Other uncertainties would 

be on top of this systematic measurement error. Finally, SC&A notes that there are no HTO 

measurement data before 1977. Since atmospheric tests would be expected to generate the 

largest amount of tritium, an estimation procedure for environmental dose for this period needs 

to be developed. An estimation procedure for the pre-measurement period, notably the 1963– 

1970 period when there were several important inadvertent vents of tests, needs to be developed. 

It is not clear that the reasoning in the TBD that HTO doses were low for the post-1977 period 

would apply to the first two decades of NTS operation. 
Effective Date: 

December 13, 2005 

Revision No. 

0 

Document No. 

SCA-TR-TASK1-0006 

Page No. 

46 of 158 

5.5.5 Occupational Iodine-131 Data 

Finding 10: The lack of occupational environmental 131 I data for non-monitored workers 

needs to be addressed in the TBD. 

Exposures specifically considered in the Occupational Environmental Dose TBD are applied to 

non-monitored workers (ORAUT-TKBS-0008-5, page 35). Consequently, internal 131I 

exposures of non-monitored workers are currently not accounted for in the TBD. 

From 1963 onwards there were many cratering and underground tests that resulted in the release 

of 131I. The total estimated source term is 1,065 kCi (Table 5). The dominant event was test 

PALANQUIN on April 14, 1965. These releases have resulted in exposures of non-monitored 

workers and need to be accounted for. 

5.5.6 Soil Ingestion 

Finding 11: Soil ingestion pathway needs to be addressed in the TBD. 

Given the large area of NTS, it is reasonable to assume that unmonitored outdoor workers 

inadvertently ingested contaminated soil. The occupational environmental dose portion of the 

TBD (Vol. 4) does not address the problem of dose due to ingestion of radionuclides, which 

would be in addition to the intakes due to inhalation for unmonitored workers. 

Ingestion and inhalation intakes should be addressed by running calculations for intakes by both 

routes and summing them in different proportions. Ingestion will be adventitious and is likely to 

be in amounts of no more than a few tens of milligrams of soil per day with a claimant-favorable 

guidance value of ~100 mg/day. For instance, if we assume a soil loading in air of 0.1 mg m-3 

and a breathing rate of 1.2 m3 h-1 for 8 hours, we get a soil intake rate by inhalation of around 

1 mg per day. Thus, if there is no exposure to the initial atmospheric plume, consideration of 

adventitious ingestion relative to inhalation following resuspension suggests that ingestion could 

be of greater importance than inhalation, if the bioavailability of radionuclides is comparable for 

the two routes of exposure. Set against this, for the higher actinides, the fractional GI absorption 

is likely to be <1*10-3, whereas uptake from the respiratory system to the systemic circulation is 

likely to be ~0.1. Thus, in this case, there is a ratio of 100 in bioavailability, so inhalation is 

likely to dominate ingestion. The fact that there is a crossover in dominant route depending on 

details of assumptions on amounts ingested and inhaled, and relative bioavailability, indicates 

that this issue needs to be explored in detail on a case-by-case basis for workers who spent a 

significant amount of time outdoors. 
 

 

Effective Date: 

December 13, 2005 

Revision No. 

0 

Document No. 

SCA-TR-TASK1-0006 

Page No. 

47 of 158 

Table 4: Size of NTS Areas Contaminated with Plutonium-239,240 as Determined by 

Soil Inventory Data 

Contaminated area Percentage of area NTS Area with 239,240 NTS Area size (km Pu 2

) used for inventory Number calculation (km2

) contamination 

1 70 69 99% 

2 52 51 98% 

3 83 84 100% 

4 41 41 100% 

5 246 8 3% 

6 212 84 40% 

7 52 50 96% 

8 34 36 100% 

9 52 52 100% 

10 54 52 96% 

11 67 10 15% 

12 104 100 96% 

14 67 - 0% 

15 96 91 95% 

16 73 37 51% 

17 80 81 100% 

18 231 71 31% 

19 388 380 98% 

20 259 16 6% 

22 83 - 0% 

23 13 - 0% 

25 578 2 0% 

26 57 1 1% 

27 130 - 0% 

29 161 - 0% 

30 150 1 1% 

Total 3,433 1,316 38% 
 

Effective Date: 

December 13, 2005 

Revision No. 

0 

Document No. 

SCA-TR-TASK1-0006 

Page No. 

48 of 158 

Table 5: Ambient Radiation Measurements at NTS Areas 

Area with maximum Maximum radiation Area 3 radiation Year radiation (mrem yr-1) (mrem yr-1) 

1967 3 318 318 

1968 3 285 285 

1978 10 320 200 

1979 12 191 190 

1980 20 207 199 

1981 3 218 218 

1982 10 209 188 

1983 20 206 181 

1984 7 327 162 

1985 7 347 78 

1986 7 318 150 

1987 19 246 184 

1988 19 223 207 

1989 2 217 205 

1990 20 192 187 

1991 3 194 194 

1992 19 189 173 

1993 20 213 200 

1994 15 143 62 

1995 5 212 150 

1996 5 225 151 

1997 30 170 131 

1998 7 201 137 

1999 7 191 135 

2000 7 217 161 

2001 2 299 151 

 Source: NTS TBD Vol. 4, Table 4.3.1-2, pp. 38–39. 
 

 

 

Effective Date: 

December 13, 2005 

Revision No. 

0 

Document No. 

SCA-TR-TASK1-0006 

Page No. 

49 of 158 

Table 6. Iodine-131 Releases from Underground and Cratering Tests that Resulted in 

the Detection of Offsite Radioactivity 

Test Date 131I (kCi) 

Yuba 5-Jun-63 0.000022 

Eagle 12-Dec-63 0.00228 

Oconto 12-Jan-64 0.001 

Pike 13-Mar-64 0.36 

Alva 19-Aug-64 0.000037 

Drill 5-Dec-64 0.0122 

Parrot 16-Dec-64 0.0046 

Sulky 18-Dec-64 13 

Alpaca 12-Feb-65 0.000024 

Palanquin 14-Apr-65 910 

Tee 7-May-65 0.0016 

Diluted Waters 16-Jun-65 0.0177 

Red Hot 5-Mar-66 0.2 

Fenton 23-Apr-66 N.A. 

Pin Stripe 25-Apr-66 0.2 

Double Play 15-Jun-66 0.12 

Derringer 12-Sep-66 0.00024 

Nash 19-Jan-67 0.0138 

Midi Mist 26-Jun-67 0.00026 

Umber 29-Jun-67 0.00052 

Door Mist 31-Aug-67 0.008 

Hupmobile 18-Jan-68 0.12 

Cabriolet 26-Jan-68 6 

Buggy 12-Mar-68 40 

Schooner 8-Dec-68 15 

Pod 29-Oct-69 0.000078 

Scuttle 13-Nov-69 0.000004 

Snubber 21-Apr-70 0.0055 

Mint Leaf 5-May-70 0.08 

Baneberry 18-Dec-70 80 

Diagonal Line 24-Nov-71 0.00136 

Riola 25-Sep-80 0.00058 

Glencoe 22-Mar-86 0.000000009 

Mighty Oak 10-Apr-86 0.0024 

Source: NCI 1997, Tables 2.2 and 2.3 (pp. 2.8 and 2.9) 
Effective Date: 

December 13, 2005 

Revision No. 

0 

Document No. 

SCA-TR-TASK1-0006 

Page No. 

50 of 158 

Figure 1: Portions of the NTS Surveyed by the Radionuclide Inventory and 

Distribution Program 

(Source: McArthur 1991) 
 

Effective Date: 

December 13, 2005 

Revision No. 

0 

Document No. 

SCA-TR-TASK1-0006 

Page No. 

51 of 158 

Figure 2: Distribution of Plutonium-239,240 on NTS as of January 1, 1990 

Isopleth levels are 500, 1,000, and 10,000 nCi m-2 (McArthur 1991) 
Effective Date: 

December 13, 2005 

Revision No. 

0 

Document No. 

SCA-TR-TASK1-0006 

Page No. 

52 of 158 

Figure 3: Locations of Atmospheric and Underground Nuclear Tests, Industrial Sites, 

and Operating Radioactive Waste Management Sites on the Nevada Test Site 

(Source: Hechanova and O’Neill 1998) 
Effective Date: 

December 13, 2005 

Revision No. 

0 

Document No. 

SCA-TR-TASK1-0006 

Page No. 

53 of 158 

Figure 4: NTS Ionisation Chamber Sampling Locations at NTS, July 1966 to June 

1967, marked 3a, 5a, 6a, 12a, 18a, 20a, 23a, 27a 

(Source: REECo 1968) 
Effective Date: 

December 13, 2005 

Revision No. 

0 

Document No. 

SCA-TR-TASK1-0006 

Page No. 

54 of 158 

Figure 5: Areas with Cesium-137 Contamination and Approximate Locations of NTS 

Ionisation Chamber Sampling Locations (hexagons) at NTS, July 1966 to June 1967 

(Sources: REECo 1968; McArthur 1991) 
Effective Date: 

December 13, 2005 

Revision No. 

0 

Document No. 

SCA-TR-TASK1-0006 

Page No. 

55 of 158 

Figure 6: Offsite Dose Rates Related to Ploughshare Test SCHOONER (from area 19) 

(Source: http://www2.nci.nih.gov/I131/intros/BK0.html) 
Effective Date: 

December 13, 2005 

Revision No. 

0 

Document No. 

SCA-TR-TASK1-0006 

Page No. 

56 of 158 

Ionization Chamber Measurements [mR/day] 

1.6 

1.4 

1.2 

1 

0.8 

0.6 

0.4 

0.2 

0 

300 

250 

200 

150 

100 

50 

0 

NTS Test Yiel kt [d ]

Tests 

AREA 3 

AREA 6 

AREA 12 

AREA 23 

AREA 27 

01-Jul-66 09-Oct-66 17-Jan-67 27-Apr-67 

Figure 7: Ambient External Gamma Radiation at Nevada Test Site, July 1966 to 

June 1967 

(Source: REECo 1968) 
Effective Date: 

December 13, 2005 

Revision No. 

0 

Document No. 

SCA-TR-TASK1-0006 

Page No. 

57 of 158 

1.5E-07
 

Beta activity in air [μCi m-3] 

area 3 

area 12

1.0E-07
 area 6 

area 27 

area 23 

5.0E-08 

0 50 100 150 200 250 300 350 

Ambient radiation [mrem yr-1] 

Figure 7: Correlation between Ambient External Gamma Radiation and Beta Activity 

in Air at the Nevada Test Site, July 1966 to June 1967 

(Source: REECo 1968) 

5.6 ISSUE 6: INTERNAL DOSE 

5.6.1 Overview 

Finding 12: Numerous issues related to the reconstruction of internal dose need to be 

investigated. 

In this section, a review is provided of the occupational internal dose component of the Technical 

Basis Document (TBD) for the NTS. The information reviewed is included in Volume 5 of the 

NTS TBD, ORAUT-TKBS-0008-5, Revision No. 00, September 2004 (herein referred to as NTS 

TBD Vol. 5.) 

A special characteristic of the NTS is that most of the activities are conducted in projects (often 

of short duration), and that radiological protection activities are tied to those projects (NTS TBD 

Vol. 5, pages 10 and 11). It is not clear whether this has been the case throughout the operations 

of the NTS, which is a matter to be clarified, but this seems likely to have been the case. Even if 

this has not been the case, it is clear that the potential for internal exposure and the mix of 

radionuclides to which workers could have been exposed will have differed substantially from 

project to project. Thus, for the purposes of dose reconstruction, it is fundamental that the dose 

reconstructor should begin by developing a timeline of the work history of the claimant matched 
Effective Date: 

December 13, 2005 

Revision No. 

0 

Document No. 

SCA-TR-TASK1-0006 

Page No. 

58 of 158 

to the various projects that occurred at the NTS during the period of employment of the claimant. 

Though implicit in the text, this needs to be brought out clearly as an overarching principle, as it 

applies more strongly at NTS than at some other facilities, where similar activities persisted for 

many years and provided a context in which more limited special campaigns occurred. This 

finding is divided into a series of sub-elements described in the following sections. Interspersed 

in these sub-elements are both Findings and Observations. 

An overarching suggestion that might be helpful in addressing many issues related to 

reconstructing internal doses to workers who entered contaminated area shortly following 

atmospheric tests, but had inadequate internal dosimetry, is to carefully consider the extensive 

data and dose reconstruction protocols that have been developed by the Defense Treat Reduction 

Agency for reconstructing internal doses to veterans who supported weapons testing at the NTS. 

5.6.2 Important Details as Regards Interpretation of Various Kinds of Internal Dose Data 

are Not Included in the NTS TBD Vol. 5 

The wide range of projects and radionuclides of potential relevance at the NTS meant that a wide 

variety of bioassay procedures were adopted. It appears that in the early period of site activities, 

there was an emphasis on screening (NTS TBD Vol. 5, page 10). This seems consistent with the 

view that external exposures generally dominated, and that significant internal exposures 

constituted incidents. However, such screening generally provides no more than an indication 

that significant internal contamination may have occurred. It may be appropriate to insert a 

caution to the dose reconstructor that such samples should not be interpreted quantitatively. This 

should be obvious in respect to nasal swabs, but there may be a temptation to treat initial urine 

samples as having the same status as later samples, whereas they may have been collected under 

very different circumstances (e.g., spot versus 24-hour samples) and may have been at greater 

risk of contamination (e.g., from soil or fecal material). NTS TBD Vol. 5 provides useful detail 

on the methods by which bioassay samples were analyzed, but almost nothing on how they were 

collected. Knowledge of methods of collection is fundamental to determining how such samples 

should be interpreted and the weight that should be attached to the results obtained. Although 

descriptive information is sometimes provided, e.g., ‘24-hour urine sample,’ it is very sparse. 

For example, no information is provided on when urine samples were given for different projects 

or under different potential exposure conditions (end of shift, before shift, 24-hour collection). 

Section 5.2.3 of the NTS TBD Vol. 5 (page 21) does give some information on correcting for 

urinalysis volume, but the contents of the four bottles are not specified, so the interpretation of an 

‘equivalent 24-hour sample’ is obscure. Also, the collection of both 24-hour and spot (single 

void) urine samples is identified (but not the circumstances under which samples of different 

types were taken), and a statement is included that normalization was made to total 24-hour 

excretion. However, it is not clear what basis was used for normalization. This could, for 

example, have been by volume or by creatinine content. Further to this point, there are 

confounding relationships between the volume of urine excreted and the biokinetics of 

radionuclides that should be explicitly recognized. For example, high intakes of fluids (either 

occurring routinely or encouraged if an intake of tritium was suspected) decrease the half-life of 

tritium in the body and modify the relationship between concentration in urine and amount 

excreted per day. In this case, dose calculations are most robustly undertaken by assuming that 

the tritium concentration in urine is representative of the concentration in body water. However, 
 

Effective Date: 

December 13, 2005 

Revision No. 

0 

Document No. 

SCA-TR-TASK1-0006 

Page No. 

59 of 158 

in the case of uranium, the evidence suggests that the fractional loss in urine per day is 

approximately independent of fluid intake, so the concentration in urine will vary inversely with 

the excreted volume, and correction to a standard volume is necessary if the current body burden 

is to be inferred. 

The wide variety of bioassay procedures adopted was selected to determine intakes and body 

contents of different radionuclides. Although some of the techniques were specifically directed 

to particular radionuclides (e.g., thyroid counting for radioisotopes of iodine), others were of 

wider applicability. Specifically, several different techniques, if applied to the same individual, 

would provide complementary information on intakes of a particular radionuclide. Thus, for 

example, on page 10 of the NTS TBD Vol. 5, it is recognized that urine and fecal sampling, 

together with lung and whole-body counting, are useful to detect and assess intakes of actinides. 

Although this is recognized, the NTS TBD Vol. 5 gives very little indication to the dose 

reconstructor as to how bioassay measurements either from a single technique or from multiple 

techniques should be used in dose estimation. It is tempting to restrict the TBD to providing 

factual information and to leave issues of interpretation to other documents, but this is not 

possible. A view has to be taken on how the data will be used to determine what information is 

to be included and what excluded from the summary provided in the TBD. The NTS TBD 

Vol. 5 needs to be substantially augmented to provide clear guidance on how the bioassay data 

are to be used to generate reconstructed doses to claimants. This key aspect of the work is 

scarcely addressed. 

In Table 5-1 (NTS TBD Vol. 5, page 12), Minimum Detectable Activities (MDAs) are given for 

various in-vitro sample analyses. Information is given for fecal samples for all the actinides, 

except for 244Cm. It is thought that this is an oversight. The information for 244Cm should be 

obtained and added. In Footnote “a” to this table, a reference is made to adjustments to the 

minimum detectable amount for larger sample sizes. It is not clear what adjustments were made 

or how they were justified. The text should be expanded to address these issues. 

Section 5.2.2.1 includes a very useful table (Table 5-2) on the relative abundance of various 

radioisotopes of iodine. However, it is based on calculations undertaken in the late 1950s and 

early 1960s. It should be confirmed that the nuclear data used in those calculations were fit for 

purpose, notably in terms of the half-lives used. It is unlikely that there will be significant 

revisions, but it is a Finding that here, and throughout, historical data should not be accepted at 

its face value. If possible, such calculations should not simply be reproduced, but should be 

checked and confirmed. In this case, the calculations should be straightforward. In other cases, 

the information available may not be sufficient for the calculations to be reproduced. In such 

cases, it should be explicitly stated that it has not been possible to confirm the original 

calculations. 

In some of the descriptions of early methods for source preparation (e.g., for Americium, as 

described on page 14 of the NTS TBD Vol. 5), the precipitate produced from the radiochemical 

procedure is described as being slurried onto a stainless steel plate for counting. Although the 

original documentation on the methods has not been checked, the terminology used suggests that 

a thick source of ill-defined geometry could have been produced. For alpha counting, this could 

imply substantial variations in the relationship between count rate and sample activity from 
Effective Date: 

December 13, 2005 

Revision No. 

0 

Document No. 

SCA-TR-TASK1-0006 

Page No. 

60 of 158 

sample to sample. The original procedures and results of counting of standards need to be 

examined to see whether this was the case. 

Also relationships are given between mass of an element and count rate (see Section 5.2.2.3 of 

NTS TBD Vol. 5). Such relationships can only apply to a particular mix of radioisotopes, but 

this is not specified. The fundamental quantities determined are count rates and mass 

concentrations are of little relevance in the current context. 

On page 15 of the NTS TBD Vol. 5 and elsewhere, there are references to old compliance 

criteria that imply particular biokinetic assumptions. Thus, 0.02 pCi of 239Pu in a 24-hr sample 

of urine is stated to represent less than 5% of a maximum permissible body burden of 239Pu. 

When analyzing the data, care should be taken to use the underlying observations, e.g., 

concentrations of 239Pu in urine, and not interpretations of those observations, e.g., body burden, 

as such interpretations are contingent on the biokinetic model in use at the time. It may be worth 

inserting a cautionary footnote on this point. 

It is assumed that MDA-based calculations will be performed for all radionuclides of relevance, 

as required. However, the interpretation of MDA-based calculations will be very different, 

depending on the radionuclide in question. In the case of tritium, monitoring often occurred only 

quarterly. HTO has a half-life in the body of only 10 days in temperate conditions, and 

considerably less in the desert conditions in Nevada, where fluid intakes would have been high in 

normal circumstances (and potentially further enhanced if tritium contamination was known or 

suspected). Therefore, quantification of intakes that could have occurred as much as 90 days 

before monitoring would be practically impossible, since the intake would have occurred 

between 9 and more than 20 biological half-lives earlier, depending on total fluid intake. In 

contrast, for plutonium, urine monitoring is primarily useful in estimating the accumulated body 

burden, rather than recent intakes, and daily excretion is less affected by environmental 

conditions (though the concentration in urine can be affected because of variations in the volume 

excreted). For uranium, the situation is more complex, as excretion reflects both recent intakes 

and the accumulated body burden in a way that depends on the previous pattern of intakes. 

These comments illustrate the general issue that the NTS TBD Vol. 5 is strong on the 

quantification of MDA values, but weak on how bioassay data (including both positive results 

and MDA values) are to be used in dose reconstruction. In particular, it would be useful to 

provide a comprehensive set of MDA values and explicit calculations of how the annual missing 

doses to be associated with those MDA values should be calculated. 

A routine use of MDA values for dose estimates without the analysis suggested above, and 

without explicit consideration of the issues discussed in the internal dose section, does not appear 

to be warranted. 

5.6.3 Lack of Early Internal Monitoring Data 

There are no internal monitoring data until late 1955, or possibly 1956. After that, bioassay data 

are sparse in terms of radionuclide coverage until the 1960s. Furthermore, the integrity of 

external dose data for some groups of workers in this same period is open to question. Therefore, 
Effective Date: 

December 13, 2005 

Revision No. 

0 

Document No. 

SCA-TR-TASK1-0006 

Page No. 

61 of 158 

internal dose estimation in this context is likely to be complex and difficult, at best, for this 

period for most radionuclides. 

In the early years of testing at NTS, intakes of radionuclides were thought to be unimportant 

relative to external dose. As a result, there exist important gaps in internal dosimetry data. 

Specifically, no personal internal dosimetry data of any kind exist for the period from the start of 

testing in January 1951 to late-1955 or 1956. At that time, Los Alamos began analyzing some 

NTS bioassay samples for plutonium. Selective tritium monitoring data exist from 1958 (NTS 

TBD Vol. 5, pg. 16). By 1961, NTS had a greater capability for internal monitoring, which 

included plutonium, tritium, and gross fission products (NTS TBD Vol. 5, pg. 8). However, 

fuller capability of internal monitoring was not established until 1967, when whole-body 

counting equipment was set up. 

As has been noted, the NTS TBD covers some aspects of dose reconstruction for the atmospheric 

testing period, including some radionuclide lists. However, the overall topic is to be covered in 

Rev. 01 of the NTS TBD (see NIOSH statements in Attachments 2 and 3). SC&A is making 

some preliminary observations regarding some issues regarding internal dose estimation during 

the atmospheric testing, since this is a topic that has been extensively discussed and analyzed in 

the context of dose reconstruction for atomic veterans. 

The 2003 review by the NAS National Research Council of the dose reconstruction program for 

atomic veterans being conducted by the DTRA throws some important light on the complexities 

of the scientific issues associated with internal dose estimation in the absence of bioassay or 

other personal monitoring data. Since there are no personal data that would enable estimation of 

internal dose, DTRA reconstructs internal doses using ratios of surface contamination to photon 

radiation, coupled with assumptions about resuspension and direct intake of fallout by armed 

forces personnel. 

Apart from the question of large particle beta dose discussed earlier in this review, the use of this 

indirect approach depends crucially on two factors: 

(1) The integrity of the external dose record 

(2) The ability to make scientifically defensible and claimant-favorable assumptions 

regarding intake due to resuspension in view of the varying and complicated patterns of 

fractionation of radionuclides 

The NAS review describes a variety of ways in which resuspension approaches to internal dose 

reconstruction can be made claimant favorable in the period immediately following nuclear 

atmospheric radionuclide releases from nuclear tests (NAS 2003, pp. 166–182). It also provides 

an analysis that points to significant factors that could lead to considerable underestimation of 

internal dose. Specifically radionuclides that are not photon emitters or weak photon emitters, 

like 90Sr and 239Pu, deposit in disproportionately large amounts in areas close to ground zero due 

to their lower volatility relative to radionuclides like 137Cs and 131I. The differential deposition 

(fractionation) is also highly variable from one test to another, a factor that can lead to large 

differences in deposition. Further, resuspension from effects due to the blast wave of 

radionuclides deposited in prior tests would greatly increase resuspension in a manner that needs 
Effective Date: 

December 13, 2005 

Revision No. 

0 

Document No. 

SCA-TR-TASK1-0006 

Page No. 

62 of 158 

to be taken into account. Finally, NIOSH should also review the specific issue of 137Cs to 90Sr 

ratios in fallout. Sherrill et al. (1975) concluded that “extreme values of the 137Cs/90Sr ratio in 

large and small [offsite] fallout particles [can be] expected to be observed in rain may range from 

about 0.2 to several times the production ratio.” The importance of this conclusion for onsite 

deposition and doses needs to be evaluated: 

Participants who engaged in activities in forward areas within a few hours after a 

shot almost certainly were exposed to previously deposited fallout that was 

resuspended to a large extent by the blast wave produced by the detonation. 

However, effects of a blast wave have been ignored in all dose reconstructions, so 

the upper bound of the resuspension factor probably has been underestimated by 

more than a factor of 100 in scenarios in which resuspension is assumed to be 

caused by walking or other light activities. In addition, plutonium was probably 

the most important inhalation hazard in previously deposited fallout, and, as 

noted above, concentrations of plutonium in fallout at the NTS are underestimated 

by a factor of about 3 or more because of neglect of fractionation. Furthermore, 

fallout that occurred more than a few months before a shot of concern has 

generally been ignored, but many prior shots contributed to fallout at the NTS 

toward the end of the period of aboveground testing. Therefore, unless 

concentrations of plutonium in fallout are overestimated by the NTPR [Nuclear 

Test Personnel Review] program by substantially more than a factor of 100 – 

which seems highly unlikely considering the interest in measuring plutonium in 

cloud samples – biases in other assumptions that tend to result in overestimates of 

inhalation radiation dose almost certainly are not sufficient to compensate for the 

neglect of blast-wave effects in all dose reconstructions at NTS. Furthermore... 

upper bounds of organ equivalent doses in this scenario could be substantially 

above 1 rem in some cases. [NAS 2003, pg. 213] 

These observations for armed forces personnel in forward areas during atmospheric testing 

would also apply to AEC and contractor personnel in forward areas during that period. They 

may also apply in some circumstances to personnel exposed to unplanned ventings during the 

underground testing program. 

A factor that NIOSH might take into consideration is that plutonium and several other metal 

oxides may be in a high-fired form, given the extremely high temperatures associated with 

nuclear explosions. Hence certain organ doses, such as those associated with the respiratory 

tract, may be considerably higher than would be estimated by a normally conservative 

assumption of Type S for dose estimation. The chemical evolution of high-fired metal oxides in 

the environment should also be considered as a factor in long-term environmental dose. 

Finally, while there are technical issues associated with the interpretation of the external dose 

records of armed forces personnel (NAS 1989), the essential integrity of those records in terms 

of whether badges were systematically left off due to economic and employment considerations 

(see below) has not arisen. Given that the integrity of the external dose record is open to 

question until the mid-1960s and possibly into the 1970s for some groups of workers, the 
Effective Date: 

December 13, 2005 

Revision No. 

0 

Document No. 

SCA-TR-TASK1-0006 

Page No. 

63 of 158 

applicability of the internal dose reconstruction approach used by DTRA would be doubtful 

unless a procedure is developed to compensate for the problems in the external dose dataset. 

5.6.4 Assigning Only Environmental Doses to Workers Thought Not to be at Risk of 

Internal Exposure may Not Capture the Full Extent of Radionuclide Intake 

Unlike universal external monitoring after 1966, not all workers were monitored for internal 

intake. Monitoring and radionuclide coverage were dependent on judgments that workers were 

at risk of internal exposure, even after the capability to monitor a range of radionuclides was 

established. The question therefore arises as to how internal doses should be reconstructed for 

workers that were not subject to bioassay because the contribution from internal dose was 

perceived, at the time, to be small. 

It seems from the NTS TBD Vol. 5 (page 35) that such workers will only be assigned 

environmental doses. However, if they were involved in particular projects, this may result in 

underestimation of their doses. A more acceptable approach may be to identify a comparable 

population of monitored co-workers and to assign doses based on dose reconstructions for those 

co-workers. The co-worker approach has been applied at other facilities, but is not addressed 

here. During the conference call with SC&A, NIOSH stated in the context of external dose 

estimation that co-worker dose could be assigned to unmonitored workers, but that guidance 

specific to NTS may not be on the calendar for development as yet (Attachment 3). 

However, it is noted that Section 5.5.4 of the NTS TBD Vol. 5 (page 36) comments that 

guidance for monitored workers with few or no bioassay measurements is under development. 

Once this guidance has been developed, consideration should be given to whether it can be 

adapted to apply to groups of unmonitored workers that may have had higher levels of internal 

exposure than would have been typical for unmonitored workers who were not at risk of internal 

exposure. 

SC&A notes that dose reconstructions should not be unduly influenced by contemporary 

judgments on the relative importance of external and internal exposure. Those judgments were 

conditioned by the environmental, biokinetic, and dosimetric models available at the time. It is 

important that internal dose reconstructions should be undertaken using the underlying data and 

best present-day techniques. Judgments on the relative importance of external and internal 

exposure should follow from these reconstructions, and should not be imposed a priori. It is 

clear from other site profiles, that NIOSH intends that this principle should be followed, but it is 

important to state it explicitly here, as there is the potential that dose reconstructors may rely on 

apparently authoritative statements made at the time that internal exposure was not an issue. 

Such statements have to be confirmed by quantitative calculations. 

Because of the type of operations that occurred at NTS, a wide variety of different radionuclides 

was of relevance. The specific radionuclides differed from context to context. As noted above, 

one of the strengths of the NTS TBD is that it identifies the radionuclides of interest in various 

contexts (though SC&A has also noted that some of these lists are not complete). However, it is 

a weakness that this is done on a case-by-case basis, so no overview is ever provided to the dose 

reconstructor of the radionuclides that may need to be taken into account. 
Effective Date: 

December 13, 2005 

Revision No. 

0 

Document No. 

SCA-TR-TASK1-0006 

Page No. 

64 of 158 

It would strongly facilitate auditing of dose reconstructions if a master list of all radionuclides of 

potential relevance to monitoring or of possible radiological significance was drawn up and 

displayed early in the NTS TBD Vol. 5. There is a list in NTS TBD Vol. 2 (pg. 37), but it is 

incomplete and does not indicate that time dependence could be completed and refined for this 

purpose. The dose reconstructor could then proceed by first screening that list to identify which 

radionuclides were of relevance to the particular claimant under consideration, and then 

determining what quantitative information was available on those radionuclides determined to be 

of relevance. Documentation of the screening aspect would help to ensure that a full audit trail 

was created of all qualitative and quantitative decisions made in dose reconstruction. Although 

this is an overarching issue that has relevance to all site profiles, the wide variety of 

radionuclides and contexts occurring at NTS means that this requirement has first been identified 

in this context. SC&A notes that 134Cs is omitted from the list of radionuclides of primary 

dosimetric concern at NTS TBD Vol. 5, page 10. As 137Cs is listed, this omission is surprising. 

5.6.5 The NTS TBD Vol. 5 has Not Adequately Explored Intake of Radionuclides via the 

Ingestion Pathway 

On a related point, it appears that the bioassay data are to be interpreted as if the intakes were by 

inhalation only (direct plume inhalation and resuspension). However, intakes by ingestion would 

also have occurred. For example, site experts have indicated that eating was allowed along the 

major highway that went through the test site, including right over old test sites (Attachment 4). 

The relative importance of ingestion versus inhalation can only be addressed by running 

calculations for intakes by both routes, and summing them in different proportions. Ingestion 

will be adventitious and is likely to be in amounts of no more than a few tens of milligrams of 

soil per day (see NCRP 1999). If it is assumed for illustration that the soil loading in air is 0.1 

mg m-3 and a breathing rate of 1.2 m3 h-1 for 8 hours, the soil intake rate by inhalation is around 1 

mg. Thus, if there is no exposure to the initial atmospheric plume, consideration of adventitious 

ingestion relative to inhalation following resuspension suggests that ingestion could be of greater 

importance than inhalation, if the bioavailability of radionuclides is comparable for the two 

routes of exposure. Set against this, for the higher actinides, the fractional GI absorption is likely 

to be <1*10-3, whereas uptake from the respiratory system to the systemic circulation is likely to 

be ~0.1. Thus, in this case, there is a ratio of 100 in bioavailability, so inhalation is likely to 

dominate ingestion. The fact that there is crossover in dominant route depending on details of 

assumptions on amounts ingested and inhaled, and relative bioavailability, indicates that this 

issue needs to be explored in detail on a case-by-case basis. An analysis of the importance of 

addressing both ingestion and inhalation in interpreting bioassay data needs to be included in the 

NTS TBD Vol. 5. 
Effective Date: 

December 13, 2005 

Revision No. 

0 

Document No. 

SCA-TR-TASK1-0006 

Page No. 

65 of 158 

5.6.6 The NTS TBD Vol. 5 does Not Adequately Consider the Possibility of Exposure to 

Different Enrichments of Uranium 

On page 17 of the NTS TBD Vol. 5, it is proposed that the ratio of the radioactivity of 238U to 

234U in urine can be used as an indicator of exposure to Depleted Uranium (DU) or Highly 

Enriched Uranium (HEU). The criteria given are that DU has a 238U:234U in the range of 3 to 10, 

HEU has a ratio of about 0.1 or smaller, and natural uranium has a ratio of 1 or less. However, 

the discussion does not address the possibility of workers being subject to exposure to uranium 

of different degrees of enrichment at different times. As uranium in urine reflects a mix of 

uranium that has recently entered the systemic circulation and remobilization of older deposits, 

notably in mineral bone, there are potentially large ambiguities of interpretation in this context. 

This issue needs to be discussed explicitly. 

On page 18 of the NTS TBD Vol. 5, reference is made to a survey of approximately 60 nonoccupationally exposed adults residing in the southwestern portion of Nevada who were sampled 

to determine the natural uranium background. The use of these survey data needs to be better 

explained. The implications of the text seem to be that a high percentile of the distribution from 

the non-exposed population would be used to identify occupationally exposed individuals. The 

text does not address the issue of any background subtraction to be made once the occupationally 

exposed individuals have been selected, but this may also be intended. Given the variability of 

natural background concentrations, it is realistic and claimant favorable to assume that such a 

background subtraction could be negligible in any individual case and, therefore, not to make 

any correction for background. This should be stated. As to excluding individuals, the main 

consideration is not whether the concentration could have arisen from natural exposure, but 

whether the concentration is radiologically significant if it had arisen from NTS exposure. On 

this basis, it seems more appropriate to treat the total concentration in urine as derived from 

NTS, if this was consistent with the work history of the individual. In this approach, the survey 

of non-occupationally exposed individuals would not be used to impose a lower limit on the 

uranium concentrations in urine considered for dose reconstruction. 

Incidentally, in the survey results for non-occupationally exposed, it is odd that the 99.9th 

percentile is higher for total uranium than it is for the sum of 234U and 238U. The presence of

235U cannot account for this difference. NIOSH should provide an explanation on this point. 

5.6.7 Use of ORAUT-OTIB-0002 

The recommendation in the NTS TBD (Vol. 5, pg. 35) that the initial evaluation of internal dose 

to non-metabolic organs be done using ORAUT-OTIB-0002 is not in accord with the restrictions 

for the use of this guidance document. ORAUT-OTIB-0002 is restricted to post-1971 workers 

who did not re-enter tunnels. Further, any use of ORAUT-OTIB-0002 should be justified by 

examining radionuclide lists and the reasonableness of using a one-time intake. 

ORAUT-OTIB-0002 (pg. 8) restricts the use of the intakes for NTS to the period after 1971 for 

workers who did not re-enter tunnels. By contrast, the NTS TBD suggests that ORAUT-OTIB0002 be used for a general initial screening test for maximum dose calculation for non-metabolic 

organs (Vol. 5, pg. 35), without specifying any other restrictions. At a minimum, the restrictions 
Effective Date: 

December 13, 2005 

Revision No. 

0 

Document No. 

SCA-TR-TASK1-0006 

Page No. 

66 of 158 

in ORAUT-OTIB-0002, including the one restricting it to post-1971, non-tunnel re-entry 

workers, should be made explicit in the NTS TBD, in order to prevent incorrect and inconsistent 

use of ORAUT-OTIB-0002. 

Further, it is not clear that ORAUT-OTIB-0002 can be used as a screening maximum dose 

approach, even with the explicit restriction to post-1971 workers who did not re-enter tunnels. 

For instance, the radionuclide list for reactor testing re-entry workers is likely to be larger. They 

may have been exposed repeatedly to gross fission products internally and externally (see 

above). Just the internal GI-tract dose considerations discussed in Finding 2 above would appear 

to invalidate the use of ORAUT-OTIB-0002 for these workers. SC&A suggests that any use of 

ORAUT-OTIB-0002 for post-1971 workers be accompanied by an explicit analysis showing that 

the doses would be bounding, and by a further exclusion of reactor re-entry workers. 

5.6.8 Miscellaneous Internal Dose Issues 

At the bottom of page 23 of the NTS TBD Vol. 5, it is stated that the MDA is directly 

proportional to the photon intensity (by which yield per decay is meant). This is surely incorrect. 

The MDA would be expected to scale in inverse proportion to the yield. This material should be 

checked and amended, as required. 

On page 25 of the NTS TBD Vol. 5, it is surprising that the whole-body count sensitivities listed 

in Table 5-7 were only just adequate to detect the normal 40K content of the body. This seems to 

indicate an exceptionally low sensitivity system, as 40K is generally very prominent in such 

systems. The reasons for this low sensitivity should be pursued. 

On page 29 of the NTS TBD Vol. 5, there seem to be two errors by a factor of 10 in the 

CWT-cm column of Table 5-11. 40.3 should be 4.03, and 28.0 should be 2.80. These errors 

should be corrected. 

On page 31 of the NTS TBD Vol. 5, although wound dose is not estimated, presumably the 

occurrence of a contaminated wound initiated programs of special monitoring, e.g., of urine, that 

would have provided results that could be used in dose reconstruction. This matter should be 

discussed. Also on page 31, it is pointed out that air-sampling records were considered as 

workplace-monitoring records rather than intake monitoring. It is further noted (page 32) that 

correlation between sample concentrations in given rooms and work locations and a specific 

person would be difficult. These views are endorsed, as is the conclusion that the use of airmonitoring data should be considered only as a last resort. 

On page 34 of the NTS TBD Vol. 5, where contamination external to the lung is mentioned in 

relation to chest counting, the reader may not understand that this includes internally 

incorporated radionuclides taken up in the ribs. This should be stated explicitly. 

On page 47 of the NTS TBD Vol. 5, entry 042 in Table 5D-3 is ambiguous. Which isotopes of 

californium are included? This point should be clarified. 
Effective Date: 

December 13, 2005 

Revision No. 

0 

Document No. 

SCA-TR-TASK1-0006 

Page No. 

67 of 158 

On page 50 of the NTS TBD Vol. 5, the MDA for tritium in urine changes from 5*106 pCi/L 

from 1958 to 1976, to 1*103 pCi/L from 1977 to 1987, 3*102 pCi/L from 1988 to 1999, 

1*103

 pCi/L from 2000 to 2002, and 5*103 pCi/L from 2003 to present. It is understandable that 

the MDA should have been high in the early days. However, modern techniques of analysis 

were in place well before 1977 (liquid scintillation detection was in place by 1966, see page 16), 

so it is not clear why the MDA did not come down earlier. Furthermore, it is not clear why the 

MDA has increased by more than an order of magnitude since 1999, bearing in mind that the 

value was stable from 1988 to 1999. This raises the question of whether the MDA was 

optimistically estimated over that period, and whether the true value was higher. 

Similarly, the MDA for 239Pu in urine changed from 0.9 pCi/24-hr from 1954 to 1957, to 

0.0225 pCi/24-hr from 1958 to 1960, 0.00225 pCi/24-hr from 1961 to 1976, 0.05 pCi/L from 

1977 to 1987, and 0.01 pCi/L from 1988 to 2000. The reason why the MDA sharply increased 

from 1976 to 1977 by about a factor of 30 (assuming a 24-hr sample of 1.4 L) remains 

unexplained. 

Other MDAs have not been examined at the same level of detail, but this sequence of values 

raises some interesting questions. MDA values should be carefully scrutinized for consistency, 

and the reasons for any anomalies identified and described. The review process would be 

facilitated if MDA values were converted to common units, as has been done here. 

On page 53 of the NTS TBD Vol. 5, it is noted that the MDA for 99mTc increased between 1967 

and 1993 (Table 5D-7). No reason is provided. The issues raised are similar to those outlined in 

the context of MDA values for tritium and 239Pu. 

On page 55 of the NTS TBD Vol. 5, the meaning of the central column in Table 5D-9 is obscure. 

This meaning should be clarified. 

5.7 ISSUE 7: EXTERNAL DOSE 

5.7.1 Overview of External Dose 

Finding 13: Protocols for reconstructing external dose during testing need to be further 

developed and the guidance for reconstructing doses to workers subsequent to testing needs to 

explore and address a number of issues. 

The external dose volume of the NTS TBD (Vol. 6) is, in many respects, a well-based technical 

document with detailed descriptions of dosimetry practices and dosimeters that were in use at 

various periods. The information given in the TBD is useful and important for dose 

reconstruction and, in some respects, claimant favorable. Specifically, the NTS TBD guidelines 

are more claimant favorable than the dose reconstruction guidelines specified for the Idaho 

National Laboratory (see Section 7). The following presents sub-elements of this finding and 

includes both Findings and Observations. 
Effective Date: 

December 13, 2005 

Revision No. 

0 

Document No. 

SCA-TR-TASK1-0006 

Page No. 

68 of 158 

5.7.2 Early Open Window Dose 

Open window dose was not recorded until 1966, so there is the issue of how beta dose is to be 

estimated up to that time. NIOSH has said it will address this question in Rev. 01. 

The potential for beta exposure would be expected to vary greatly from one area to the next and 

from one period to the next at NTS. For instance, the beta exposures during atmospheric testing 

would be expected to vary from one test to another, and also to be quite different from those 

during tunnel re-entry. These exposures, in turn, would be different from the reactor testing or 

waste-handling exposures. NIOSH’s development of methods to estimate beta exposures during 

the period up to 1966 will presumably take these differences into account, especially if ratios of 

beta to photon exposures are used. SC&A notes that as NIOSH develops methods to fill the data 

gap, adequate account should be taken of the problem of large particle beta dose for re-entry 

workers, and the limitations that this would impose on the beta-gamma ratio approach. 

5.7.3 Data Integrity 

Data integrity questions exist, at least for some job types regarding the external dose record, due 

to a reported off-normal practice of the intentional non-use of individual monitors during work in 

radiation areas. The problems may extend to the mid-1960s or possibly even into the 1970s. 

Potentially the most important problem identified with external dose records concerns data 

integrity in the early period. Site experts have noted that personnel working in radiation areas 

with a high potential for external dose, notably forward areas in the nuclear testing program, took 

off their badges from time to time in order to keep quarterly recorded dose below the 3 rem limit. 

The NTS radiation protection procedure established that a person who received a dose of more 

than 3 rem in a quarter was not allowed to enter a radiation area. This procedure would imply 

the possible loss of overtime pay and extra forward-area compensation. Site experts have 

independently and consistently stated that this practice did occur (Attachments 4 and 5). It is 

unclear how long this continued, but it may have gone on to some extent until well into the 

underground testing program. One possible time when the practice may have decreased is about 

1966, when the integrated film and ID badge was introduced. Since an ID badge was essential to 

demonstrate legitimate presence at NTS, the practice of taking off the film badges thereby 

became more difficult, and appears to have been essentially eliminated at this time. However, 

other site experts indicated that the problems with personnel deliberately removing their badges 

in radiological areas may have extended into the 1970s (Attachment 4). These questions about 

data integrity are reinforced by clear historical documentation about compensation and 

employment policies at NTS (see Section 7.1.1 on completeness of data, and Hacker 2004, 

pg. 90). 

Given that most of the personal dosimeters at NTS were returned with zero recorded dose, the 

resolution of the data integrity issue is crucial to the integrity of external dose estimates. Zero 

readings are normally interpreted as representing a dose below the limit of detection. This is a 

reasonable and defensible assumption only if it is established that the dosimeter was consistently 

worn in radiological areas. If, as appears possible, a significant number of workers in certain 

radiological areas did not do so, then the problem of external dose estimation may become acute, 
Effective Date: 

December 13, 2005 

Revision No. 

0 

Document No. 

SCA-TR-TASK1-0006 

Page No. 

69 of 158 

not only because the individual data would be open to question, but the co-worker data may also 

be similarly open to question. During his interview with SC&A, Mr. Brady, a senior health 

physics official, stated that he himself had put his badge between 2-inch thick lead bricks and 

also had done the same for the badge of the monitor with him. Other site expert interviews done 

by SC&A indicate that some workers put their dosimeters between rocks, which were more 

easily available and less obvious in terms of the effort to avoid the recording of doses. 

These considerations regarding data integrity need to be investigated for all forward areas. 

Besides nuclear weapon test areas (atmospheric and underground), reactor test areas would also 

likely have been affected, given the potential for significant dose due to early re-entry (see 

above). Waste-handling areas and bomb assembly facilities should also be considered. 

5.7.4 The TBD does Not Contain Complete Instructions for Converting External 

Dosimetry Data into IREP Inputs 

Due to the special and highly varied nature of the activities at NTS, there was potential for 

exposure to an exceptionally large array of radionuclides from various irradiation geometries. 

Since these radionuclides have photon emission spectra that cover all three ranges of the inputs 

required for IREP, which is used to calculate the probability of causation, it appears crucial for 

the dose reconstructor that the TBD should define the photon energy spectrum and irradiation 

geometry for each type of work or installation. However, NIOSH did not find it essential that 

this information should be in the TBD, when this question was raised in the September 9, 2005, 

conference call between NIOSH and SC&A (Attachment 3): 

SC&A inquired whether Rev. 01 would contain instructions for converting 

dosimetry data into inputs for IREP that is covered in other TBDs but which is not 

available in Rev. 00 of the NTS TBD. NIOSH responded that such information 

would be provided by dose reconstruction supervisors and that the TBD was not 

there to provide all details. 

SC&A pointed out that the details in question were essential, since their absence 

could result in inconsistent dose reconstruction. Without uniform guidance on the 

topic, different dose reconstructors would come up with different numerical 

values for the doses for the same exposure conditions. 

This ad hoc approach to providing information to dose reconstructors regarding photon spectra 

led to additional comments during the conference call that are worth noting in this context 

(Attachment 3): 

...in the present context, the important question [that SC&A was asking] was: Is 

NIOSH saying that the TBD does not provide instructions for dose reconstruction. 

NIOSH responded by stating: “That is correct.” 

SC&A understands that not all dose reconstruction data and guidelines can be included in a 

TBD. However, guidelines that are needed to prevent significant inconsistencies between dose 
 

 

Effective Date: 

December 13, 2005 

Revision No. 

0 

Document No. 

SCA-TR-TASK1-0006 

Page No. 

70 of 158 

reconstructions should be included in the TBD. In this instance, SC&A finds that due to the 

complexity of the problem and the variety of radionuclides at NTS and exposure geometries, 

basic guidelines for photon spectra and geometries associated with various jobs and locations 

should be specified in the TBD, in order to prevent inconsistencies in dose reconstruction. It is 

SC&A’s recommendation that as much explicit guidance as possible be incorporated into the 

TBDs, and that NIOSH continue to develop workbooks with detailed instruction manuals as a 

means to ensure that this guidance is implemented in a consistent manner. Based on discussions 

held at recent meetings of the Advisory Board, it appears that this approach to the preparation of 

TBDs is being implemented. 

5.7.5 Extremity Dosimetry 

The NTS TBD Vol. 6, does not contain information about extremity dosimetry. Further, the 

status of NTS bomb assembly workers and their exposure records appears to be unclear so far as 

the NIOSH set of TBDs is concerned. 

Extremity doses could be far higher than whole-body exposure under some circumstances at 

NTS, as for instance during weapon assembly or decontamination activities. Such doses could 

also have been significantly higher for workers handling waste drums, opening them, and 

performing other activities such as dewatering and repackaging wastes. Site expert interviews 

(Attachment 4) indicate that multiple badging to measure doses to various parts of the body was 

practiced in later years, but that the dose of record was from the main badge. Extremity badging 

appears to have been used from sometime in the 1970s. The TBD does not contain information 

on extremity dose monitoring or on how the dose of record might need to be supplemented for 

certain groups of workers if the results of multiple badging are not in the dose record. 

SC&A raised this issue generally during the conference call of September 9, 2005. NIOSH’s 

response was restricted to bomb assembly workers: 

NIOSH responded that it had not come across any cases for bomb assembly 

workers for whom this topic was most relevant. It is possible that this information 

is classified. Up to the present moment, NIOSH has not looked into it. 

(Attachment 3) 

In a later communication (Attachment 6), NIOSH stated that it appeared that bomb assembly had 

been done by Los Alamos and Livermore personnel, but that no reference to that has been 

located: 

Response: Bomb assembly was undoubtedly performed by a small cohort. It 

would have been done by weapons lab (LANL, LLNL, etc.) people and not by 

REECo staff. Weapons lab dosimetry people should have addressed this issue, 

and it should be in their TBDs. I have been unable to find reference to it in the 

LANL TBD on external dosimetry. I have a call in to the author of that section. 

The LLNL external dosimetry section has not yet been approved. 
Effective Date: 

December 13, 2005 

Revision No. 

0 

Document No. 

SCA-TR-TASK1-0006 

Page No. 

71 of 158 

In view of the nature of these exposures, there are undoubtedly classification 

issues that would require an adequate clearance to address. It would seem 

appropriate, therefore, to formulate a special task involving one or more 

specialists with the appropriate clearance and experience to develop an 

unclassified Complex wide guidance document on this issue. (Attachment 6) 

SC&A agrees with NIOSH that investigating this issue is of considerable importance to this 

group of workers, not only for extremity doses, but generally regarding the status of the bomb 

assembly group of workers and their dose records. 

Finally, the issue of extremity doses is far broader than bomb assembly workers. The revised 

TBD should assess the extent to which workers holding certain types of jobs, such as 

decontamination and decommissioning, or waste handling and repackaging, may have had 

extremity exposures that were significantly higher than the dose of record. The existence of 

multiple-badging for at least some groups of workers may shed light on this issue, as well as on 

the more general question of geometry of organ dose relative to the dose of record. 

5.7.6 Angular Dependence of the Individual Monitors for Ground Surface Irradiation 

Geometry Needs to be Taken into Consideration 

The NTS TBD states “the effect (of angular dependence)...is generally minimal...for angles of 

incidence ranging from about 30 to 150 degrees.” The TBD also states: “...for angles 

approaching parallelism (i.e., 0 degrees) with the plane of the film, the effect [lower response] 

can be pronounced, and can lead to significant underestimates in dose. The problem should be 

minimal for exposures at NTS, because these were typically...at angles close to normal with the 

plane of the film” (NTS TBD Vol. 6, pg. 16). 

The report “Film badge dosimetry in atmospheric nuclear tests,” NAS 1989, page 77, states, 

“The irradiation geometry for a worker standing on a contaminated field may be considered to be 

best approximated by the rotational geometry. The worker immersed in a hemi-spherical cloud 

of radionuclides may be considered to be also in the rotational geometry.” For workers that 

entered extended contaminated areas after, for example, an air test, the worker may be 

considered to be standing on a plane whose surface is uniformly contaminated. The best 

approximation to this exposure geometry is the rotation geometry. 

For individual dosimetry made for ground contamination, there will be loss of response of the 

dosimeter due to: 

(a) The angular dependence 

(b) The absorption of photons going through the worker 

(c) The fact that the dosimeter is placed higher than the main ICRP 60 organs of interest 

These losses have been partially compensated for by assuming in the TBD an AP exposure 

geometry for the irradiation. The adoption of the AP factors for this exposure case is claimant 

favorable — for photon energies above 250 keV, a positive bias of around 20% will be seen with 

respect to the rotational geometry. However, for “best case” dose estimates, NIOSH still has to 
 

Effective Date: 

December 13, 2005 

Revision No. 

0 

Document No. 

SCA-TR-TASK1-0006 

Page No. 

72 of 158 

correct the general dose conversion factors published in its procedures. This is a matter that is 

generic and being resolved on that basis in technical discussions between NIOSH, SC&A, and 

the Advisory Board. 

SC&A notes here that issues of geometry may especially affect certain job types, such as tunnel 

re-entry and drillbacks in the test areas, waste repackaging, maintenance on rocket engine test 

reactors, and so on. NIOSH, in responding to SC&A comments on this issue in the specific 

instance of the Mallinckrodt Chemical Works, developed an approach for assessing the 

correction factors that would be needed for organ dose compared to badge location on a jobspecific basis. NIOSH used the ATTILA model, as well as facility-specific job-type information 

to perform the calculations (SC&A 2005a, Attachment 4, pp. 64–70). NIOSH should perform an 

assessment of job types at NTS in various periods, as well as the situations involving external 

environmental dose, to determine which ones need correction factors to make external dose 

estimates scientifically sound and claimant favorable. Multiple-badging data, available at NTS, 

may be helpful in the implementation of this suggestion. 

5.7.7 Neutron Doses 

Neutron dose data are lacking until 1966 and are partial until 1979. The TBD does not provide a 

basis for estimating some neutron doses. 

The NTS TBD states that neutron tracking Type A film (NTA film) badges were part of the 

integrated dosimeter-ID card introduced in 1966. In Table 6-1, and elsewhere in the NTS TBD, 

NIOSH recognizes and quantifies the problem of low or no response of this type of neutron 

dosimeter to low neutron energies (the threshold is variously described as 800 keV or 500 to 

800 keV, pg. 10 and pg. 32). SC&A is in general agreement with the limitation of NTA film as 

to its lack of sensitivity to low neutron energies, and that such film is suitable only for neutron 

energies above 1 MeV (NTS TBD Vol. 6, pg. 32, see especially Figure 6-7). However, on page 

13 of the same volume, the NTS TBD claims that the integrated badge introduced in 1966 was 

capable of measuring all types of radiation, including “thermal neutrons.” This error should be 

corrected. 

The NTS TBD discussion regarding the correction factors to be used for the neutron exposure 

situations cited in Section 6.3.4.3 (Vol. 6, pp. 41–45) is generally claimant favorable and 

appropriate. 

The NTS TBD also discusses the use of neutron-to-photon ratios from the Pantex plant for the 

purpose of estimating neutron exposures for bomb assembly personnel. SC&A has found, in the 

context of its review of the TBD for the Iowa Army Ammunition Plant, that that ratio is likely to 

be claimant favorable, but also cautioned that it is preferable to use site-specific data whenever 

possible (SC&A 2005b, Finding 8, pp. 29–31). In response to a question posed by SC&A, 

NIOSH has indicated that there are considerable gaps in the information relating to who did the 

bomb assembly and where their dosimetry data might be. NIOSH indicated that LANL and 

Livermore personnel may have done the assembly, but also that those TBDs do not appear to 

have the relevant information (Attachment 6). It appears, therefore, that some archival research 
Effective Date: 

December 13, 2005 

Revision No. 

0 

Document No. 

SCA-TR-TASK1-0006 

Page No. 

73 of 158 

remains to be done to address the questions, and NIOSH has indicated that it seems appropriate 

to pursue that research (Attachment 6). SC&A concurs that this should be done. 

However, the TBD does not discuss the estimation of neutron doses in the pre-1966 period or in 

cases where low-energy neutrons might be a significant part of the dose, notably for some 

personnel involved in atmospheric testing (see below) and handling of plutonium-contaminated 

wastes, where the neutrons would be moderated by the non-nuclear waste material that 

dominates the weight and volume of low-level waste contaminated with plutonium. It is not 

clear that the Pantex neutron-to-photon ratio would be claimant favorable in this context. For all 

areas with neutron exposure potential other than the Gravel Gerties, a scientifically sound 

approach to neutron dose estimation needs to be developed. 

5.7.8 Neutron Exposure During Atmospheric Testing 

The assumption that neutron exposure during atmospheric testing “was practically non-existent” 

is not based on an analysis of the problem, and may not be correct for some groups of workers. 

Page 29 of the NTS TBD Vol. 6, states that neutron exposure from nuclear explosions “was 

practically non-existent.” There were a number of tower and air detonations at the NTS and 

prompt high-energy neutrons can travel a long way in air. It is assumed that the minimum 

distance considerations for personnel at atmospheric tests were determined based on heat and 

blast effects. It is possible that such considerations precluded neutron doses in practice. 

However, neutron dosimetry as a function of distance from atmospheric tests has been 

extensively studied and published in the open literature (Hacker 1994, pp. 92–95). NIOSH 

should analyze this literature, as well as the actual practices of the AEC and DOD during 

atmospheric testing, to evaluate whether there was a possibility of neutron exposure during some 

tests. This appears to be especially desirable in view of pressures from DOD on the AEC to 

allow for reduced distances for stationing of troops, which would also probably have meant 

reduced distances for AEC and contractor monitoring and possibly other personnel. There were 

tensions between the AEC and the DOD on this and other radiological safety issues (Hacker 

1994). 

The effect on the monitors and laborers of the DOD and AEC policies and actual practices 

during troop training exercises needs to be evaluated for each test, and especially for those tests 

where neutron doses might play a role. DOD estimates of neutron doses for its personnel 

indicate that these doses were highly variable from one test to another (NAS 2003, pg. 74). 

Furthermore, while these neutron dose estimates indicate low-neutron exposures relative to 

photon doses, NIOSH should carefully evaluate the DOD dose reconstruction practices on both 

counts before coming to the conclusion that neutron doses were “practically non-existent” during 

atmospheric testing. This is especially important, since there are no neutron dose measurements 

from the atmospheric testing period, and since the NAS review of the DOD estimates has 

concluded that neutron exposures to some armed forces personnel could be significant: 

Most test participants were not exposed to neutrons, except for observers in 

trenches at NTS tests and a few cloud sampling personnel. For most participants 

who were exposed to neutrons, the doses were very low. However, a small 
Effective Date: 

December 13, 2005 

Revision No. 

0 

Document No. 

SCA-TR-TASK1-0006 

Page No. 

74 of 158 

number of volunteer observers in trenches very close to ground zero did receive 

substantial neutron (and gamma) doses during some NTS tests (Goetz et al. 

1981). (NAS 2003, pg. 158) 

Since AEC and REECo Rad-Safe monitors responsible for test safety were in the same areas as 

armed forces personnel and generally preceded them into areas near ground zero for the purpose 

of doing surveys, it is quite possible and even likely that small groups of them also got high 

exposures. Moreover, in at least one instance, a Rad-Safe monitor was on a mission 

accompanying armed forces personnel in aircraft (Attachment 5). It appears, therefore, that the 

assumption regarding neutron doses during atmospheric testing in the TBD needs to be revisited 

and carefully analyzed in relation to actual practices for specific groups of employees. 

There are also some other issues regarding neutron exposures in other areas. Page 28 of the NTS 

TBD (Vol. 6) states: “no single individual had access to areas in which there was potential for 

neutron exposure.” This is taken to mean: “Staff worked in pairs in areas in which there was 

potential for neutron exposure.” This was probably correct for weapon assembly, but not for 

well-logging or neutron calibration facilities. Page 28 also states that “...if workers were unmonitored for neutrons...then it is highly unlikely that a neutron exposure occurred.” This is not 

consistent with page 29 of the same document: “if neutron dose information is not available for 

those involved with final assembly and arming operations, ...neutron-photon ratios may be 

used.” The TBD should adopt clearer guidelines for the dose reconstructor as to the possibility 

of neutron dose. 

5.7.9 Miscellaneous External Dose Issues 

On page 10 of the NTS TBD, it states in Table 6.1 that the bias is 1.00 for photons for these 

years. In the detailed description of the response of the film dosimeter used from 1961 to 1966 

(page 38), it is stated that the bias is 1.25 due to the loss of information of low-energy photons. 

It is suggested that the bias value in Table 6.1 be changed to 1.25. 

On page 10 of the NTS TBD, it can be seen in the Table 6-1, column “Description” for the three 

film badges, that there is no overlap in the low and high dose measurement range. For the 

DuPont 556 Packet, there is in fact a “gap” between 5 and 10 R. For instance, if the dosimeter 

were irradiated with a 6 R exposure, the low-range element would show an exposure higher than 

5 R, but the high range element would not show anything. It is suggested that the TBD should 

include a recommendation to the dose reconstructor on how to proceed in such cases. 

On page 17 of the NTS TBD, there is the term “above the uncertainty edge of the filter;” the term 

“uncertainty edge” should be better defined. 

On page 20 of the NTS TBD, in the equation Dc = CF x (Di – Do), Dc is defined as the calibration 

factor, as is CF from the text immediately above the equation. The terms Do (actual dose) and Di 

(indicated dose) are also not clear. 

On the page 25 of the NTS TBD, it is stated “at the 90% confidence level.” This should be “at 

the 95% confidence level.” 
Effective Date: 

December 13, 2005 

Revision No. 

0 

Document No. 

SCA-TR-TASK1-0006 

Page No. 

75 of 158 

On the page 26 of the NTS TBD, Table 6-4, the entry “0–150” is a typographical error. Also on 

this page, it is not correct to use the standard deviation of the background TLDs from all the 

monitored sites (as shown in Table 6.4) to calculate the LLD. The correct method is to 

determine the standard deviation of a background measurement at one site. The procedure is 

more or less as follows. Twenty monitors are prepared and left for a month in a low-background 

area. The monitors are read, and the mean and standard deviation are calculated. This standard 

deviation is then used to calculate the LLD. As the above standard deviation will likely be less 

than the 0.057 mrem/day quoted for the deep dose in Table 6-4, the approach used in the TBD is 

claimant favorable. 

On page 31 of the NTS TBD, the legend of Figure 6-6 is not correct. It should read, “Conversion 

coefficients for personal dose equivalent Hp(10,00

) per unit Dose equivalent H as a function of 

neutron energy.” 

On page 34 of the NTS TBD, Figure 6-9 could be made more informative by extending the line 

of the graph up to at least 20 MeV. Also the y-axis title is not understandable. It should be 

Tracks/cm2

 per mrem. 

On page 39 of the NTS TBD, there is a typographical error; the footnotes should be numbered 

(1) and (2). 

On page 42, the X axis title should be “MeV.” The caption of the figure should say “thickness of 

moderators.” 

5.8 ISSUE 8: MEDICAL DOSE 

Finding 14: The guidance regarding the reconstruction of medical doses needs to address 

additional medical exposure scenarios, including the use of photofluorography, and additional 

uncertainties associated with routine chest x-rays. 

The TBD does not provide any positive documentation that photofluorography was not used. In 

its response to SC&A questions on this issue (Attachment 3, Item #6), ORAU stated that, 

“[t]here is no documentation or anecdotal information that PFG was used.” NIOSH assumes that 

there was no photofluorography done at NTS. This would not be an issue in cases where it can 

be established that a worker wore a film badge or TLD during the x-ray procedure. However, 

where this was not the case, more positive evidence of the type of equipment is needed. This is 

also true of the period 1957 to 1970 where there are no data at all about the type of equipment 

that was used and for which period NIOSH guidance indicates the PFG should be assumed in the 

absence of data. 

The uncertainties in medical dose appear to be understated as a generic matter in NIOSH Site 

Profiles. SC&A has discussed this issue in detail in the review of the Rocky Flats TBD and that 

discussion is not repeated here. 
 

Effective Date: 

December 13, 2005 

Revision No. 

0 

Document No. 

SCA-TR-TASK1-0006 

Page No. 

76 of 158 

6.0 OBSERVATIONS 

6.1 ENVIRONMENTAL DOSE 

6.1.1 Verification is needed of Environmental Monitoring Data Referenced in the TBD 

A suitable reference nuclide for inhalation of outdoor air at NTS is 239/240Pu. The procedure 

outlined in the TBD suggests taking the bigger of the annual averages of environmental 

monitoring data and inferred air concentration using soil inventory data and resuspension. If the 

exact location of an employee is not known, site average values should be used. 

The TBD claims in ORAUT-TKBS-0008-4 that the concentrations in Tables 4.2.1.2.2-1 are 

“typically the average of the maximum concentration for a given area and a given year. In cases 

where maximum values were not provided, the average of the concentrations was reported.” 

Table 7 shows the results of the comparison for the years 1996, 1999, and 2000 with data in the 

Nevada Test Site Annual Site Environmental Reports cited in the TBD. Not all values that were 

entered in Tables 4.2.1.2.2-1 could be verified. In particular, no data were entered for some 

areas even though data were reported in the Environmental Report (e.g., Area 2 in CY 1996). In 

some cases, the reported value does not correspond to the average for the site (e.g., Area 4, 

CY 2000). 

SC&A has not performed a detailed check of the data entry in the TBD, but notes this 

discrepancy as an indication that the QA/QC procedures for data entry in the TBD may need to 

be improved. 

6.1.1.1 There are Gaps in the Soil Data for 239/240Pu, as well as Other Questions Regarding 

Adequacy of 239/240Pu Characterization. 

The data for average annual intakes in Table 4.2.2-2 of the TBD are based on TBD Table 2-8. 

Both tables contain no 239/240Pu inventory data for Areas 23, 25, 26. However, air monitoring 

data are available for Areas 23, 24, 25, and 26. It is not reasonable to assume that some areas 

have no 239/240Pu inventory at all. 

Further, there appear to be some discrepancies in soil inventory of some radionuclides in some 

areas. For instance, Table 2-5 lists the inventory of 239 + 240Pu in surface soil (0 to 5 cm) for 

Project 56 in Area 11 as 36.00 curies, while Table 2-8 lists the 239 + 240Pu for all of Area 11 to be 

29 curies. Moreover, since the Table 2-8 is derived from McArthur 1991, the reported inventory 

should be for the top 15 cm, which accentuates the discrepancy. As another example, Table 2-8 

does not mention Area 13, even though Area 13 is discussed in the text in the context of this 

table (NTS TBD Vol. 2, Section 2.3.13, pg. 34) while Table 2-5 lists the soil inventory of 239 + 

240Pu as 46 curies. 

6.2 INTERNAL DOSE 

The NTS TBD does not evaluate the issue of high-fired plutonium oxide, or other high-fired 

oxides of actinides such as uranium and americium, or of certain fission products like strontium 
Effective Date: 

December 13, 2005 

Revision No. 

0 

Document No. 

SCA-TR-TASK1-0006 

Page No. 

77 of 158 

and cerium isotopes. The existence of a certain proportion of high-fired oxides in fallout from 

weapons tests and rocket engine tests should be investigated. For some radionuclides, solubility 

considerations appear to be rather restricted. For instance, only Type M is listed for americium 

and cerium isotopes. NIOSH should justify the use of these solubilities in light of the specific 

conditions under which the oxides would have been created either during weapons tests or the 

reactor testing program. 

On page 19 of the NTS TBD Vol. 5, the first paragraph of Section 5.2.2.9 provides a very brief 

discussion of the deposition of various elements in human tissues. This material is valid, but 

does not provide a sufficient basis for dose reconstruction. It would be better to provide 

references here and elsewhere to the specific tools to be used in dose reconstruction, e.g., IMBA. 

Although, in general, the descriptions of analytical techniques are adequate, the description 

under Section 5.2.2.10 of the NTS TBD Vol. 5 (page 21) is not sufficient. Gamma spectrometry 

is an inadequate description. There is a need to know whether it was NaI- or HPGe-based. The 

1993 method is adequately described, but the 1961 technique is not. It seems likely that a NaI 

system was used at that date, but nothing is said about the crystal size or geometry. A history of 

the changes in equipment used from 1961 to 1993 would be helpful. This presumably could be 

synthesized from REECo (1993b) and related source documents. 

Under in-vivo counting on page 22 of the NTS TBD Vol. 5, it seems odd to have to assume that 

chest counting at the new facility used Phoswitch detectors. The facility opened in 1981, so it is 

difficult to believe that there is not a full record available of the equipment installed and used. A 

record should be identified and used to augment this account. 

On page 22 of the NTS TBD Vol. 5, it is also noted that the background subtraction for the 

whole-body and chest counting was not the standard channel-by-channel approach, but was an 

activity-based subtraction. It is not clear why this approach was used, as it seems to sacrifice 

some detail in the data. A comment on this point would be helpful. 

6.3 EXTERNAL DOSE 

In regard to external dose, the TBD should examine multiple badging and its relevance for 

estimating organ dose for groups of workers and periods when such data are not available. In 

addition, the matter of the recording practices of doses from each badge worn needs clarification. 
 

 

 

 

 

 

 

 

 

 

 

 

Effective Date: 

December 13, 2005 

Revision No. 

0 

Document No. 

SCA-TR-TASK1-0006 

Page No. 

78 of 158 

Table 7. Atmospheric Concentrations of Plutonium-239,240 (pCi m-3) for the Nevada 

Test Site 

Area Size (m2) a 

CY 1996 CY 1999 CY 2000 Inferred soil 

resuspension c TBD b) Env Rep d 

(avg of max) TBD b Env Rep e (avg of avg)b TBD b Env Rep f (avg of max) 

1 6.90E+07 7.5E-04 7.5E-04 4.8E-05 8.5E-05 8.5E-05 4.6E-04 

2 5.10E+07 3.5E-05 1.8E-05 4.3E-05 5.6E-04 

3 8.40E+07 3.0E-04 3.4E-04 1.1E-04 2.7E-04 2.8E-04 5.6E-04 

4 4.10E+07 8.1E-05 5.9E-05 5.9E-05 5.9E-05 1.0E-04 1.3E-03 

5 7.50E+06 1.6E-05 2.2E-05 8.5E-06 2.1E-05 2.1E-05 8.4E-04 

6 8.40E+07 4.6E-05 4.6E-05 2.1E-05 4.1E-04 4.1E-04 1.3E-04 

7 5.00E+07 4.5E-04 4.5E-04 1.4E-05 3.4E-05 3.4E-05 4.2E-04 

8 3.60E+07 3.9E-03 

9 5.20E+07 6.1E-04 6.1E-04 1.3E-03 2.8E-03 2.8E-03 2.2E-03 

10 5.20E+07 5.8E-05 5.8E-05 4.5E-05 1.1E-04 2.8E-03 

11 1.00E+07 1.9E-05 1.9E-05 3.5E-03 

12 1.00E+08 3.7E-06 3.7E-06 4.9E-04 

15 9.10E+07 2.4E-04 2.4E-04 1.1E-05 1.1E-05 2.6E-04 2.6E-04 8.8E-04 

16 3.70E+07 1.8E-06 1.8E-06 1.3E-04 

17 8.10E+07 2.9E-04 

18 7.10E+07 3.5E-06 3.5E-06 1.1E-05 8.9E-06 1.0E-05 1.0E-05 1.8E-03 

19 3.80E+08 4.6E-04 

20 1.60E+07 4.5E-06 4.0E-06 2.0E-05 7.3E-06 6.6E-06 6.6E-06 3.3E-03 

23 6.3E-06 6.3E-06 

25 2.30E+06 4.2E-06 4.2E-06 6.2E-06 6.2E-06 1.1E-05 1.1E-05 

26 5.20E+05 

27 2.6E-06 2.6E-06 

28 

30 7.80E+05 2.4E-02 

Average 

of data 1.6E-04 1.5E-04 2.1E-05 1.3E-04 3.6E-04 3.2E-04 2.5E-03 

Weighted 

average 

2.0E-04 1.3E-04 3.7E-04 8.9E-04 

(a) Source: TBD, Table 4.2.2-1 

(b) Source: TBD, Table 4.2.1.2.2.-1 

(c) Calculated by multiplying TBD, Table 2-8 values with resuspension factor of 1.3x10-9 m-1 

(d) Nevada Test Site Annual Site Environmental Report for Calendar Year 1996, DOE/NV11718-137, 

October 1997, page 5-29 

(e) Nevada Test Site Annual Site Environmental Report for Calendar Year 1999, DOE/NV11718-463, page 4-25 

(f) Nevada Test Site Annual Site Environmental Report for Calendar Year 2000, October 2001, 

DOE/NV11718-605, page 5-35 
 

Effective Date: 

December 13, 2005 

Revision No. 

0 

Document No. 

SCA-TR-TASK1-0006 

Page No. 

79 of 158 

7.0 OVERALL ADEQUACY OF THE SITE PROFILE AS A BASIS FOR 

DOSE RECONSTRUCTION 

The SC&A procedures call for both a “vertical” assessment of a site profile for purposes of 

evaluation specific issues of adequacy and completeness, as well as a “horizontal” assessment 

pertaining to how the profile satisfies its intended purpose and scope. This section addresses the 

latter objective in a summary manner by evaluation of (1) how, and to what extent, the site 

profile satisfies the five objectives defined by the Advisory Board for ascertaining adequacy; 

(2) the usability of the site profile for its intended purpose, i.e., to provide a generalized technical 

resource for the dose reconstructor when individual dose records are unavailable; and (3) generic 

technical or policy issues that transcend any single site profile that need to be addressed by the 

Advisory Board and NIOSH. 

7.1 THE FIVE OBJECTIVES 

The SC&A review procedures, as approved by the Advisory Board, require that each site profile 

be evaluated against five measures of adequacy: completeness of data sources, technical 

accuracy, adequacy of data, site profile consistency, and regulatory compliance. Each of these is 

discussed below. 

7.1.1 Objective 1: Completeness of Data Sources 

For the period after NTS bioassay capability was established, the NTS TBD Vol. 5 is strong on 

information on analysis techniques, but weak on sampling techniques in respect of bioassay 

materials. Also, normalization techniques were applied to results obtained from the analyses, but 

the details of those normalizations are not given. Attachment 5D provides a good account of the 

codes used in bioassay records and should allow the original records to be readily scrutinized. 

Some information on in-vivo counting procedures is given there, but this is mainly referenced to 

other documents (e.g., REECo 1993a), which have only been briefly reviewed at this time. 

In regard to external dose, the NTS TBD has carefully documented the characteristics of the 

dosimeters in use in various periods and their detection limits. The external dose volume of the 

TBD provides a solid account of the practices as they evolved and as reported in the supporting 

documentation. 

The TBD is particularly strong in regard to the technical basis of recent external and internal 

dose procedures, since it is based on guidance and evaluations that have been prepared and 

periodically updated since the 1990s. 

As is evident from the reference lists at the ends of the six volumes of the NTS TBD, NIOSH has 

made an extensive data capture effort and used a considerable amount of this literature in the 

preparation of the NTS TBD. Further, NIOSH has also been in frequent contact with site 

experts. The list of contacts was provided by NIOSH to SC&A, and is reproduced in Annex A to 

Attachment 3 of this report. NIOSH has especially been in frequent contact with the health 

physics and record keeping staff at NTS. 
Effective Date: 

December 13, 2005 

Revision No. 

0 

Document No. 

SCA-TR-TASK1-0006 

Page No. 

80 of 158 

Yet, NIOSH’s literature search and site expert contacts are incomplete in crucial ways. In regard 

to literature, NIOSH makes no mention of the official history of nuclear test radiation safety 

between 1947 and 1974, written by Barton C. Hacker, entitled Elements of Controversy: The 

Atomic Energy Commission and Radiation Safety in Nuclear Weapons Testing 1947–1974. This 

book contains nearly 200 pages of notes to the text, including a large number of references to 

primary sources on radiation safety. It also contains an excellent bibliography. While the book 

is about much more than employee radiological safety at NTS, omission of any reference to it in 

the NTS TBD is surprising. The book and associated materials could provide valuable insights 

into conditions prevailing during the tests, as well as the operational practices in regard to 

radiological safety. 

For instance, Dr. Hacker’s book makes clear that there were conflicts between personnel safety 

and the policies of compensation for employees, and that the problems emerged early. Here is 

how he describes the 1952–1953 period leading up to the Upshot-Knothole test series in 1953: 

Problems persisted, however, raising concerns in Washington about the fate of 

workers. AEC Chairman Dean, in particular, wondered just what standards and 

safeguards applied. Santa Fe Operations reported matters well under control. 

Areas reading 100 milliroentgens per hour or more were posted; work parties in 

such areas required a monitor present. Personnel film badges were read and 

recorded daily, after each shift for workers in areas regarded as contaminated. 

The accepted national standard of 0.3 roentgen per week was strictly enforced but 

integrated over a longer time. Santa Fe Operations set the limit for TumblerSnapper roll-up as 3 roentgens, gamma only, in ten weeks; the Division of 

Biology and Medicine concurred but only after changing the limit to 

3.9 roentgens per quarter. Nearing that total barred a worker from 

contaminated areas; exceeding that total meant transfer or layoff. 

[Hacker 1994, pg. 90, emphasis added] 

Since work in forward areas was paid more than work in other places, approaching the quarterly 

limit was clearly associated with a significant economic penalty for employees; the penalty for 

exceeding it could be as severe as a layoff. Hence, the compensation and employment system 

created systematic incentives for employees to compromise radiation safety in favor of pay and 

job security. Dr. Hacker’s book provides extensive references to primary documentation for the 

policies and controversies discussed in this paragraph (Hacker 1994, Note 52, pg. 327) that 

would be a very useful guide to the pressures that led to what appears to have been a significant 

compromise of the integrity of the external dose record in the early period. 

There were also tensions between weapons testing and safety, at least in the early period: 

Immediate questions about worker safety merged into larger questions about the 

wisdom of further testing in Nevada. The request from Washington for a report 

on workers also asked for an “early study of the operational future for Nevada 

Proving Ground.” ...Overseeing the study General Fields, the director of military 

application, stressed three questions: “A. What steps can be taken to minimize 

contamination both in the immediate test area and off site? B. What steps can be 
 

 

 

 

Effective Date: 

December 13, 2005 

Revision No. 

0 

Document No. 

SCA-TR-TASK1-0006 

Page No. 

81 of 158 

taken to improve documentation procedures? C. What steps can be taken to 

eliminate or minimize existing and anticipated health and public relations 

problems? [Hacker 1994, pg. 90] 

How this tension between safety and continued testing was resolved and what aspects of the 

resolution led to more safety and which ones to better public relations is a material issue that 

needs to be investigated as NIOSH prepares Rev. 01 of the NTS TBD. This is especially 

relevant since Elements of Controversy documents the “discontent” of the armed forces with 

AEC radiation exposure limits, which was the context in which the AEC relaxed its rules and 

allowed armed forces personnel to be present closer to the tests than previously allowed (Hacker 

1994, pg. 92). Rad-Safe personnel would also have been present at the same locations as the 

armed forces personnel. Rad-Safe personnel generally preceded armed forces personnel into 

areas near ground zero. Both factors would tend to increase external and internal exposure. 

Stationing personnel closer to ground zero also raises questions about the extent of neutron 

exposure during atmospheric testing that bear close examination and analysis. As discussed 

above, NIOSH’s conclusion that personnel were not exposed to neutrons during nuclear weapons 

tests is premature at best. Study and analysis of primary documentation, including possibly still 

classified documentation about the tests, may be especially useful. Specifically, the possibility 

that troops (and hence Rad-Safe personnel) were stationed closer than permitted distances 

appears to be an important item of investigation. 

SC&A recognizes that NIOSH plans to cover atmospheric testing in Rev. 01 of the NTS TBD. 

However, there are important conclusions about dose estimates and radiological testing during 

this period in Rev. 00 of the NTS TBD. As discussed above, the TBD contains a conclusion that 

neutrons were not an important source of radiation exposure during the atmospheric testing 

period. Furthermore, the Barton Hacker work extends well into the period of underground 

testing. 

One of the most important issues in regard to completeness of data sources is the lack of a 

detailed interview (and associated follow-up) with William J. Brady who worked in security and 

radiation safety at the NTS for nearly the entire period of atmospheric and underground testing, 

from January 1952 to July 1991, when he retired as Principal Health Physicist. Mr. Brady has 

also been on National Research Council committees that have investigated radiation doses to 

atomic veterans and dosimetry and dose estimation practices in that context. 

Only a very modest contact with Mr. Brady appears to have been made regarding the use of R, 

rad and rem (See Attachment 3, including Annex B to Attachment 3).3

 His vast knowledge of 

NTS rad safety programs, incidents, off-normal practices, such as putting film badges between 

two-inch thick lead bricks to prevent the recorded dose from reaching the quarterly limit, appears 

not to have been used. Exceeding the 3-rem quarterly limit would result in a worker being 

prohibited from forward areas, and thereby loss of the additional pay accorded workers in those 

3

 Mr. Brady recalled being briefly contacted by Mr. Griffith, but does not recall any substantive 

conversation on dose reconstruction or radiation safety issues. He also said that Mr. Griffith did not identify himself 

as a consultant to NIOSH or NIOSH contractors, or that the contact was part of information gathering pursuant to 

the implementation of compensation decisions pursuant to EEOICPA. SC&A has reproduced NIOSH’s entire 

summary of the interchange as Annex A to Attachment 3. 
Effective Date: 

December 13, 2005 

Revision No. 

0 

Document No. 

SCA-TR-TASK1-0006 

Page No. 

82 of 158 

areas. Mr. Brady is also very knowledgeable about the literature and is one of the few people 

knowledgeable about radiation safety and NTS going back almost all the way to the start of 

operations there. SC&A’s interview with him is summarized in Attachment 5. It is of some 

interest and relevance to note here that the official history, Elements of Controversy, relied a 

good deal on Mr. Brady’s knowledge and expertise. 

NIOSH practices in regard to the documentation and use of the site expert interviews it conducts 

also raise some questions. During the conference call with SC&A (Attachment 3), NIOSH stated 

that it does not attempt to make summaries of substantive interviews, but rather makes notes only 

on those topics that it considers significant: 

Not all points made during the exchanges were documented or summarized. 

NIOSH only documented points that it considered useful. 

... 

... 

The notes of the site-expert and retired-worker communications are scattered. It 

would take some time to pull them out. There is no organized summary of the 

interchanges. Notes of site expert interviews that were used in Volume 2 and 

Volume 4 of the TBD are immediately available. 

These practices are questionable from the point of view of completeness of use of the available 

information. The significance of some comments may emerge only as time goes on. Omitting 

substantive comments also raises questions about how the selection of the points that are 

“considered useful” is made. 

As one important example of the need for more complete documentation of interviews, the point 

that the off-normal practice that employees sometimes took off their badges in forward areas 

during the early period (which may extend well into the 1960s) emerged consistently in SC&A 

interviews with HP personnel, including those interviewed by NIOSH. The relationship of 

higher pay in those areas to the off-normal practice appears to be apparent, an inference that can 

also be made from the safety description in Elements of Controversy quoted above. Yet the NTS 

TBD does not address this problem, which is crucial to a judgment about the adequacy of 

external dose data until the mid-1960s and possibly into the 1970s. As a result, it also contains 

no analysis as to the following: 

• 	 Which groups of workers were affected by the conflict between the compensation and 

safety policies 

• 	 Whether scientifically defensible adjustments to the data are possible and, if so, what the 

procedures should be to make those adjustments 

• 	 Whether co-worker data can be reliably constructed, given the data integrity issues that 

are unresolved 

SC&A suggests that NIOSH make a careful assessment of Barton Hacker’s history and the 

sources that are cited in it insofar as they concern on-site radiation safety practices. SC&A also 
Effective Date: 

December 13, 2005 

Revision No. 

0 

Document No. 

SCA-TR-TASK1-0006 

Page No. 

83 of 158 

suggests that NIOSH should (1) interview William Brady in depth on a far greater range of 

topics than it appears to have done, and (2) follow up on suggestions regarding documentation 

not yet considered, but which may be relevant to the dose reconstruction program. 

The TBD did not rely on classified documents in its production. Interviews with Mr. Brady, as 

well as Dr. Hacker, as to the utility of the classified documentation for NTS dose reconstruction 

would provide a useful guide. Dr. Hacker, who had access to the classified record, did not find 

that it added much to the unclassified and declassified record for the purposes of historical 

analysis; however, the conclusion may well be different for dose reconstruction since source 

terms for individual tests and other classified information would appear to be relevant, especially 

for the periods when internal dose monitoring data are not available or incomplete in important 

ways, and for the period for which there are questions as to the integrity of external dose records 

for certain groups of workers. 

SC&A also notes that there are other sources that the NTS TBD has not explored that could be 

critical to dose reconstruction for several groups of workers. Among the most important of these 

sources are the reports prepared by the NRDL for estimating doses to personnel re-entering 

reactor test areas soon after the tests. NRDL 1968 was cited by NIOSH, but its dose-related 

aspects were not presented or analyzed in the NTS TBD. NRDL 1968 also contains several 

references that have more detailed data regarding hot particles and radiation doses. SC&A 

suggests intensive study of these and related sources and archives, since they are likely to contain 

data and analytical methods that would be of material value in several different aspects of dose 

reconstruction including: 

• 	 Doses to re-entry personnel 

• 	 Organ dose implications of exposure to hot particles 

• 	 Geometry considerations relevant to dose of record relative to organ dose 

• 	 Potential long-term skin, gonad, GI-tract, thyroid, and breast radiation dose due to large 

particles incorporating radionuclides that are relatively long-lived, such as 60Co, that 

could deliver large local doses 

• 	 Far-field hot particle doses 

Such archival and analytical reviews would also likely be useful for other sites, notably Hanford, 

where large hot particles may have caused doses of a kind that may be analyzed by similar 

methods. 

Finally, the NTS TBD has not made adequate use of Congressional hearings and the 2003 NAS 

National Research Council study. The latter has not been reviewed in the NTS TBD for 

relevance and importance. An assessment of such sources is needed, especially for the period of 

about the first two decades, when there are various issues of data and analysis that are complex, 

and where SC&A has greater concerns about the data and analysis in the NTS TBD. 
Effective Date: 

December 13, 2005 

Revision No. 

0 

Document No. 

SCA-TR-TASK1-0006 

Page No. 

84 of 158 

NIOSH has acknowledged the need for a more complete investigation of sources in one area: 

bomb assembly workers. It is unclear at the present time where the relevant dose information for 

these workers is located and in what TBD it should be covered (Attachment 6). 

7.1.2 Objective 2: Technical Accuracy 

The NTS TBD does not provide adequate analysis to sustain technically accurate, “best estimate” 

doses in several areas, including: 

• 	 Issues of geometry of exposure relative to badge locations and external DCFs need to be 

addressed in the specific context of the NTS TBD to ensure that estimated doses are 

scientifically defensible and claimant favorable. The SC&A review of individual dose 

reconstructions for NTS indicates that these factors may not be as important for minimum 

and maximum dose reconstruction; however, they are likely to be significant for “best 

estimate” doses. NIOSH has acknowledged that these issues need to be addressed and 

they are under discussion on a generic basis at the Advisory Board Working Group level 

as of this writing (mid-October 2005). 

• 	 The technical accuracy of internal beta doses from hot particles has not been evaluated. 

This is likely to particularly affect skin, gonad, and GI-tract doses for workers entering 

reactor and weapons testing areas. 

• 	 The technical accuracy of the environmental dose estimation procedure is questionable 

for periods long after the test. 

• 	 The NTS TBD does not set forth a procedure for making defensible or, in some cases, 

any internal or external dose estimates for re-entry into weapon and reactor test areas at 

times soon after the tests. 

• 	 The NTS TBD does not provide adequate guidance for dose reconstruction in regard to 

specific waste handling and repacking activities. 

• 	 The TBD does not provide guidance about a procedure to take into account the effect of 

heat on film badges and TLDs stored in personal vehicles. 

Accuracy of dose reconstruction will be affected by the issue relating to the integrity of external 

dose data discussed in this review. 

7.1.3 Objective 3: Adequacy of Data 

The data and analysis presented in the NTS TBD are incomplete and inadequate for the purpose 

of reconstructing doses to many classes of employees, at least into the 1960s and possibly into 

the 1970s for weapons testing and extending into the 1970s for reactor testing and possibly other 

areas as well. In reference to early re-entry employees, data that exist have not been used. It is 

unclear whether they would be adequate, since they have not been fully evaluated. 
Effective Date: 

December 13, 2005 

Revision No. 

0 

Document No. 

SCA-TR-TASK1-0006 

Page No. 

85 of 158 

External dose data, except for neutron doses, for the period after 1966 may be adequate, provided 

that the data integrity issues can be determined to be minimal after the time that the integrated 

ID-dosimeter badge was introduced. Open window doses were also recorded after that time, 

enabling beta and low-energy photon dose estimation. The caveat in this context is that the dose 

of record needs to be supplemented by multiple-badging data, as well as analysis of exposure 

geometry (noted above). 

External and internal dose data adequacy is questionable in the following specific ways: 

• 	 There are no open window external dose data prior to 1966. There is no analysis of this 

issue in the TBD. Therefore SC&A cannot arrive at any conclusions regarding whether 

the existing data, in the form of source terms, size and nature of the tests, etc., would be 

adequate to reconstruct shallow dose, which is important for skin, breast, testes, and 

thyroid cancers. 

• 	 The integrity of the external dose record up to the mid-1960s and possibly into the 1970s, 

is open to question for some groups of workers, as discussed above. It would appear 

therefore that the adequacy of that dataset at it stands currently, that is without some 

adjustments and other data sets to complement it, for dose reconstruction is open to 

question, at best. A careful analysis of the entire problem of external exposure, the extent 

and nature of off-normal practices, and working conditions during this period is needed 

before conclusions can be made about the adequacy of the entire set of available 

information for external dose reconstruction in the early period. SC&A suggests careful 

research on instances of workers taking off badges, and employment practices such as 

transferring or laying off workers who reached or approached quarterly radiation limits. 

This should include both site expert interviews and archival research. Reference to the 

archives of key experts such as Barton Hacker, William J. Brady, and Floyd Wilcox may 

be especially useful to address this crucial issue. 

• 	 Internal dose data for the early period are non-existent (to late 1955). Tritium data are 

non-existent to the late 1950s, and detailed radionuclide analytical data only began in 

1967. It is noted that French and Skrable found that the bioassay data from E-Tunnel 

workers were limited in both the quantity and quality needed for making reasonably 

accurate estimates of their intakes and doses (NTS TBD Vol. 5, page 69). Hence internal 

dose data until well into the 1960s are sparse at best. The TBD has not developed any 

procedures based on available data, such as testing source terms and short-term 

deposition of radionuclides to allow an assessment of the adequacy of the early data for 

internal dose reconstruction. Based on the conference call with NIOSH, SC&A expects 

that these issues will be addressed in Rev. 01 of the NTS TBD (see Attachment 3). 

The NTS TBD does not provide adequate data or analysis for dose reconstruction for early reentry workers in reactor test areas, notably due to exposure to large hot particles incorporating 

mixed fission products. The NTS TBD also does not provide adequate data in this regard for 

atmospheric testing, for underground tests that vented, including Baneberry, and possibly for 

underground test early re-entry employees. 
Effective Date: 

December 13, 2005 

Revision No. 

0 

Document No. 

SCA-TR-TASK1-0006 

Page No. 

86 of 158 

Data that would enable dose reconstruction for workers re-entering reactor and weapon test areas 

within hours or days after the test appear to be available, at least to some extent. These data 

affect the entire reactor testing period from the late 1950s to 1973, and are also relevant for the 

entire atmospheric testing period. In regard to the underground testing period, an evaluation of 

the adequacy of the data for reconstruction of doses in re-entry and drillback operations is 

needed with specific reference to the kinds of issues raised by the NRDL in assessing doses to 

re-entry personnel (NRDL 1968). 

7.1.4 Objective 4: Consistency Among Site Profiles 

It is important to recognize that the NTS differs substantially from other facilities in the DOE 

Complex, because it has not hosted ongoing production of materials. Rather, the NTS was, and 

is, mainly an outdoor testing and research facility. In that context, many of the considerations 

that apply to the control and monitoring of permanent buildings are not relevant. Although this 

relaxes some requirements for consistency with other site profiles, SC&A notes that there is still 

a need to ensure that information is provided to a similar level of detail in various TBDs. 

7.1.4.1 Consistency – Internal Dose 

The NTS TBD notes here, however, that NTS compares unfavorably with other sites on internal 

dose monitoring until well into the 1960s. DOE sites and even AWE sites have some internal 

bioassay data going back to the late 1940s. NTS had none until late 1955. Even after that time, 

data are limited to plutonium, until the introduction of tritium monitoring a few years later. This 

lack of internal dose data was due to the erroneous general assumption in the early years that 

only external dose was of significance in weapons testing. Despite the deficiency of the internal 

dose data well into the 1960s, the NTS TBD does not address the issue in detail. This is unlike 

some other TBDs, where considerable attention to the quantity of data, going back to the early 

1950s is often presented. 

7.1.4.2 Consistency – External Dose 

The INEEL site and the NTS site had many work activities in common. The main source of 

photons for both sites was fission and activation products. Both sites worked with prototype 

reactors. Some of the projects at INEEL involved the controlled destruction of reactors that 

resulted in similar surface contamination scenarios as seen at NTS. The external individual 

dosimetry used in the two sites followed very similar time-lines and techniques. Therefore, the 

two sites should have similar dose-reconstructor guidelines. 

This is not the case, however. Whereas the NTS guidelines are, on the whole, claimant 

favorable, the INEEL guidelines are not. Tables 8, 9, and 10 below summarize the differences 

between the guidelines for the two sites, and also include guidelines taken from the Savannah 

River Site TBD for comparison. 
 

 

 

 

 

 

 

Effective Date: 

December 13, 2005 

Revision No. 

0 

Document No. 

SCA-TR-TASK1-0006 

Page No. 

87 of 158 

Table 8. Comparison of Photon Dosimetry 

Parameter NTS INEEL SRS 

Minimum detection limit for film dosimetry – 

DuPont type 508 emulsion 

40 mrem 10 mrem 40 mrem1 

Compensation for loss of information of dose 

due to low energy (E < 100 keV) photons. This 

loss is due to the use of the lead filter only to 

measure Hp(10). 

Multiply the 

Hp(10) by 1.25 

No compensation Add the open 

window dose to 

Hp(10) 

Energy spectrum for reactor work 30 to 250 = 100% 30 to 250 = 25% 

E > 250 = 75% 

30 to 250 = 50% 

E > 250 = 50% 

Energy spectrum for fuel processing 30 to 250 = 100%2 30 to 250 = 25% 

E > 250 = 75% 

30 to 250 = 50% 

E > 250 = 50% 

Energy spectrum for waste processing 30 to 250 = 100%3 30 to 250 = 25% 

E > 250 = 75% 

30 to 250 = 50% 

E > 250 = 50% 

Energy spectrum for calibration 30 to 250 = 100%3 30 to 250 = 25% 

E > 250 = 75% 

30 to 250 = 50% 

E > 250 = 50% 

Irradiation geometry AP3 Not given Mainly AP 

1) DuPont 552 and 558 emulsions 

2) For NTS, exposure to fission and activation products 

3) Not explicitly stated in the TKBS 

Table 9. Comparison of Neutron Dosimetry 

Parameter NTS INEEL SRS 

Minimum detection limit for NTA film 

dosimetry 250 mrem 14 or 20 mrem 30 or 40 mrem 

Bias for loss of information due to NTA 

film dosimetry (low energy neutrons) 

Multiply the Hp(10) 

by 2.5 for all workers 

Multiply the Hp(10) 

by 3 for MTR workers 

only 

Use photon to 

neutron ratio 

Energy spectrum for reactor work 0.1 to 2 MeV = 100% 

E < 10 keV = 20% 

10 to 100 keV = 5% 

0.1 to 2 MeV = 50% 

2 to 20 MeV = 25% 

10 to 100 = 15% 

0.1 to 2 MeV= 85% 

Energy spectrum for processing 0.1 to 2 MeV = 100% - 0.1 to 2 MeV = 100% 

Energy spectrum for waste processing 0.1 to 2 MeV = 100% 0.1 to 2 MeV = 5% 

2 to 20 MeV = 95% -

Energy spectrum for calibration 0.1 to 2 MeV = 100% 0.1 to 2 MeV = 20% 

2 to 20 MeV = 80% 

0.1 to 2 MeV =83% 

2 to 20 MeV = 17% 

Irradiation geometry AP3 Not given Mainly AP 

Table 10. Comparison of Beta Dosimetry 

Parameter NTS INEEL SRS 

Two window film dosimeter No beta dosimetry1 Beta dosimetry with 

MDL = 10 mrem 

Beta dosimetry with 

MDL = 40 mrem 

Multi window film dosimeter Beta dosimetry with 

MDL = 40 mrem 

Beta dosimetry with 

MDL = 10 mrem 

Beta dosimetry with 

MDL = 40 mrem 

1) From NTS: “reliable beta dosimetry was not possible until the introduction of the multi-element badge.” As 

discussed in Section 5, there are no personal beta dose data until 1966. 
Effective Date: 

December 13, 2005 

Revision No. 

0 

Document No. 

SCA-TR-TASK1-0006 

Page No. 

88 of 158 

It can be seen from the above tables that, in terms of claimant favorability, the NTS external 

TBD is the most favorable, followed by the SRS TBD. The INEEL external TBD is the least 

claimant favorable. Overall, it is possible to say that, with respect to the indicated parameters, 

the NTS and SRS TBD parameters are claimant favorable, and the INEEL TBD parameters are 

not. 

External dose data integrity issues are not discussed in the TBD. This is similar to the lack of 

discussion of that issue in the Rocky Flats TBD. 

7.1.4.3 Consistency – Guidelines 

It has been SC&A’s observation that some TBDs, such as those for Hanford and Savannah 

River, and those for AWEs, in addition to providing comprehensive background information, 

provide considerable explicit guidance for dose reconstructors. It is appears that a consistent 

philosophy regarding the purpose of the TBDs needs to be defined and communicated to the 

authors of the TBDs. In this respect, the NTS TBD does not contain comparable detail, such as 

in the matter of internal dose estimation discussed above or estimation of missing beta dose to 

1966. SC&A acknowledges here that NIOSH may include more detail in the forthcoming 

revision of the TBD. 

7.1.5 Objective 5: Regulatory Compliance 

SC&A noted no issues regarding regulatory compliance in the post-1970 period (i.e., 1971 and 

after). There are a number of potential issues for the early period related to technical accuracy 

and to data adequacy. Since the NTS TBD is incomplete in several essential respects, and since 

they may be addressed in Rev. 01 of the NTS TBD, SC&A is not providing an analysis of the 

regulatory issues associated with the first two decades of NTS operation at this time. 
 

Effective Date: 

December 13, 2005 

Revision No. 

0 

Document No. 

SCA-TR-TASK1-0006 

Page No. 

89 of 158 

8.0 REFERENCES 

42 CFR Part 82, Title 42, Public Health, Part 82. Methods for Radiation Dose Reconstruction 

Under the Energy Employees Occupational Illness Compensation Program Act of 2000, Code of 

Federal Regulations, May 2, 2002. 

Anspaugh, L. R., 2002. “Movement of Radionuclides in Terrestrial Ecosystems by Physical 

Processes,” Health Physics, volume 85, number 5, pp. 669–679, Lippincott Williams and 

Williams, Hagerstown, Maryland. 

BIOPROTA 2005. Modeling the Inhalation Exposure Pathway. A report prepared within the 

international collaborative project BIOPROTA: Key Issues in Biosphere Aspects of Assessment 

of the Long-term Impact of Contaminant Releases Associated with Radioactive Waste 

Management. Main Contributors: M. Wasiolek (Task Leader), A. Agüero, A. Albrecht, 

U. Bergström, H. Grogan, G.M. Smith, M.C. Thorne, M. Willans and H. Yoshida. Published on 

behalf of the BIOPROTA Steering Committee by BNFL (Nexia Solutions Ltd), United 

Kingdom. 

Eberhardt C.F. 1999. Using Absolute Humidity and Radiochemical Analyses of Water Vapor 

Samples to Correct Underestimated Atmospheric Tritium Concentrations (June 1999): LA-UR99-1107. 

Favor, D. N., 1987. Survey of Radon and Radon Daughter Concentrations in Selected Rainier 

Mesa Tunnels, DOE/NV/10327-31, U.S. Department of Energy, Nevada Operations Office, Las 

Vegas, Nevada. 

Hacker, Baron C., 1994. Elements of Controversy: The Atomic Energy Commission and 

Radiation Safety in Nuclear Weapons Testing 1947–1974. Berkeley, California: University of 

California Press, 1994. 

A.E. Hechanova, A.E and L.J. O’Neill, 1998. Description of the Nevada Test Site and Nellis Air 

Force Range Complex Activities in Nevada, May 1998, 

http://nstg.nevada.edu/web_pubs/ntsdesc.pdf 

LANL 2002. Environmental Surveillance at Los Alamos during 2002, LA-14085-ENV, Los 

Alamos National Laboratory, Los Alamos, New Mexico, 2002. 

McArthur, Richard D., 1991. Radionuclides in Surface Soil at the Nevada Test Site, DOENV/10845-02, Desert Research Institute, University of Nevada System, Las Vegas, Nevada, 

August 1991. 

NAS 1989. Committee on Film Badge Dosimetry in Atmospheric Nuclear Tests, Film Badge 

Dosimetry in Atmospheric Nuclear Tests. Washington, DC: National Academy Press, 1989. 
Effective Date: 

December 13, 2005 

Revision No. 

0 

Document No. 

SCA-TR-TASK1-0006 

Page No. 

90 of 158 

NAS 2003. Committee to Review the Dose Reconstruction Program of the Defense Threat 

Reduction Agency, A Review of the Dose Reconstruction Program of the Defense Threat 

Reduction Agency. Washington, DC: National Academy Press. 

NCI 1997. Estimated Exposures and Thyroid Doses Received by the American People from 

Iodine-131 in Fallout Following Nevada Atmospheric Nuclear Bomb Tests, National Cancer 

Institute. 

NCRP 1999. Recommended Screening Limits for Contaminated Surface Soil and Review of 

Factors Relevant to Site-Specific Studies, National Council on Radiation Protection and 

Measurements, Publication 129, ISBN 0-929600-61-4. 

NRC 1992. J.D. Berger, Manual for Conducting Radiological Surveys in Support of License 

Termination, Draft Report for Comment, prepared by Oak Ridge Associated Universities for the 

Nuclear Regulatory Commission, Oak Ridge, Tennessee, 1992. (No final report was located). 

NRDL 1968. Hazards to Personnel Entering the Nevada Test Site Following Nuclear Reactor 

Tests, NRDL-TR-68-49, Naval Radiological Defense Laboratory, San Francisco, California, 

December 19, 1968. 

NTS 1997. Black, S.C., and Y.E. Townsend, 1997, Nevada Test Site Annual Site Environmental 

Report for Calendar Year 1996, DOE/NV11718-137, U.S. Department of Energy, Nevada 

Operations Office, Las Vegas, Nevada. 

NTS 1999. Black, S.C., and Y.E. Townsend, 2000, Nevada Test Site Annual Site Environmental 

Report for Calendar Year 1999, DOE/NV11718-463, U.S. Department of Energy, Nevada 

Operations Office, Las Vegas, Nevada. 

NTS 2001. Townsend, S.E. and R.F. Grossman, 2001, Nevada Test Site Annual Site 

Environmental Report for Calendar Year 2000, October 2001, DOE/NV11718-605, U.S. 

Department of Energy, Nevada Operations Office, Las Vegas, Nevada. 

ORAUT-OTIB-0002. Technical Information Bulletin – Maximum Internal Dose Estimates for 

Certain DOE Complex Claims, ORAUT-OTIB-0002, July 5, 2004. 

Reynolds Electrical Engineering Company (REECo) 1968. Environmental Radioactivity at the 

Nevada Test Site – July 1966 through June 1967, NVO-410-15, May 1968. 

REECo 1993a. Technical Basis for Internal Dosimetry at the Nevada Test Site, Reynolds 

Electrical Engineering Company, 1993. 

REECo 1993b. Documents for the ORAU “O Drive” entitled “NTS General Information 1953– 

1973” containing list by year of instruments, dosimetry (mostly external), rad levels, exposure 

criteria, respiratory protection, internal contamination, and calibration information. 
 

Effective Date: 

December 13, 2005 

Revision No. 

0 

Document No. 

SCA-TR-TASK1-0006 

Page No. 

91 of 158 

Rodgers, J., P. Wasiolek, J. Whicker, C. Eberhart, K. Saxton, and D. Chandler, 2000. 

Performance Evaluation of LANL Environmental Radiological Air Monitoring Inlets At High 

Wind Velocities Associated with Resuspension, Los Alamos National Laboratory, Los Alamos, 

LA-UR-00-3091, 2000. 

Rollins 2004a. NTS TBD Vol. 1, Technical Basis Document for the Nevada Test Site – 

Introduction, ORAUT-TKBS-0008-1, Subject Expert Eugene M. Rollins, National Institute for 

Occupational Safety and Health, February 4, 2004. 

Rollins 2004b. NTS TBD Vol. 2, Technical Basis Document for the Nevada Test Site – Site 

Description, ORAUT-TKBS-0008-2, Subject Expert Eugene M. Rollins, National Institute for 

Occupational Safety and Health, February 2, 2004 

Rollins 2004c. NTS TBD Vol. 3, Technical Basis Document for the Nevada Test Site – 

Occupational Medical Dose, ORAUT-TKBS-0008-3, Subject Expert Eugene M. Rollins, 

National Institute for Occupational Safety and Health, June 9, 2004 

Rollins 2004d. NTS TBD Vol. 4, Technical Basis Document for the Nevada Test Site – 

Occupational Environmental Dose, ORAUT-TKBS-0008-4, Subject Expert Eugene M. Rollins, 

National Institute for Occupational Safety and Health, April 20, 2004 

Rollins 2004e. NTS TBD Vol. 5, Technical Basis Document for the Nevada Test Site – 

Occupational Internal Dose, ORAUT-TKBS-0008-5, Subject Expert Eugene M. Rollins, 

National Institute for Occupational Safety and Health, September 30, 2004. 

Rollins 2004f. NTS TBD Vol. 6, Technical Basis Document for the Nevada Test Site – 

Occupational External Dose, ORAUT-TKBS-0008-6, Subject Expert Eugene M. Rollins, 

National Institute for Occupational Safety and Health, September 21, 2004. 

SC&A 2004. SC&A Standard Operating Procedure for Performing Site Profile Reviews, Rev. 0, 

March 18, 2004. 

SC&A 2005a. Second Supplemental Review of the Mallinckrodt Site Profile Revision 1(Effective 

Date March 10, 2005), Second Supplement to SCA-TR-TASK1-0002, July 1, 2005. 

SC&A 2005b. Review of NIOSH Site Profile for the Atomic Energy Operations at the Iowa 

Army Ammunition Plant (IAAP) Final Integrated Version, SCA-TR-TASK1-0009c, June 2005. 

SC&A 2005c. Third Supplemental Review of the Mallinckrodt Site Profile Revision 1(Effective 

Date March 10, 2005), Third Supplement to SCA-TR-TASK1-0002. August 16, 2005. 

SC&A 2005d. Review of NIOSH/ORAUT Procedures and Methods Used for Dose 

Reconstruction. SCA-TR-Task3, January 2005. 

Sherrill, R. D.; Sumerlin, N. G.; Beck, J. N., Kuroda, P. K., 1975. “Variation of the Ratio of 

Cesium-137 to Strontium-90 in the Atmosphere,” Health Physics. Vol. 28, April 1975, pp. 335– 

340. 
Effective Date: 

December 13, 2005 

Revision No. 

0 

Document No. 

SCA-TR-TASK1-0006 

Page No. 

92 of 158 

Warren 1945, Stafford L. Warren, memorandum to Gen. Groves, “Subject: Report on Test II at 

Trinity, 16 July 1945,” July 21, 1945. 
 

 

Effective Date: 

December 13, 2005 

Revision No. 

0 

Document No. 

SCA-TR-TASK1-0006 

Page No. 

93 of 158 

ATTACHMENT 1: SC&A QUESTIONS TO NIOSH 

INITIAL SC&A QUESTIONS FOR NIOSH/ORAU 

REGARDING NTS SITE PROFILE 

May 6, 2005 

General 

1) Has NIOSH done worker and site expert interviews? If so, could NIOSH provide the 

minutes and notes of these interviews to SC&A as soon as possible? 

2) The TBD seems to emphasize the underground tests that occurred at NTS, while 

spending little time on the period of atmospheric testing. Does the statement in the 

introduction (TBD Vol. 1, pg. 7) that NIOSH is researching how to estimate dose from 

volatile radionuclides cover pathways of exposure? 

3) Specifically in relation to atmospheric testing, is NIOSH considering internal dose 

pathways from activities, such as recovery of equipment, cleanup of debris, and other 

work assignments that may have occasioned entry into contaminated zones shortly after 

tests? Has NIOSH considered external and internal doses due to fallout from presence of 

workers outdoors during some atmospheric tests? Is NIOSH investigating the doses to 

health physics monitors who may have gone into the test areas for monitoring purposes 

shortly after the tests? In Vol. 2 (pg. 28), NIOSH notes that workers did re-enter test 

areas after the tests, and that this “had the potential to cause significant external and 

internal radiation exposures.” It is not clear from the context whether NIOSH is 

considering this in detail both for the atmospheric and underground testing periods. 

Would NIOSH clarify this? What is the state of the research in characterizing this 

exposure potential other than the resuspension estimation? Vol. 6 (pg. 38) on external 

dose, for instance, cites three references for external dose for re-entry personnel, but two 

refer to general articles for fission product spectra and one is a personal communication. 

Are there sit- specific data for the statements regarding the claimant-favorable approach 

to dose estimation discussed in the paragraph just above Section 6.3.4.2? 

4) What areas of NTS are associated with AEC/DOE operations alone? How has NIOSH 

segregated exposure between DOE and DOD operations, or have they assumed all 

radioactive exposure was a result of AEC/DOE activities? Specifically, has NIOSH 

investigated whether any AEC, or AEC contractor or subcontractor personnel 

participated with armed forces personnel in the exercises at NTS? 

5) Table 2-2 in the site description lists no radionuclides of concern for Areas 3 & 11, the 

Nuclear Explosive Assembly Area (Area 27), and the Device Assembly Area (Area 6). Is 

this an oversight on the part of the TBD author or is NIOSH/ORAU indicating that there 

were no radiation exposures in these areas? Are there any area or personnel exposure 

records for these areas? 
 

Effective Date: 

December 13, 2005 

Revision No. 

0 

Document No. 

SCA-TR-TASK1-0006 

Page No. 

94 of 158 

Occupational Medical Exposure 

1) Who performed diagnostic x-ray inspections at NTS? Was the State of Nevada involved 

in this? Why was NIOSH not able to determine the machine type and factors used in 

diagnostic x-rays after 1957 and even as late as 2002 (Table 3-4, Vol. 3, of the TBD)? 

By contrast, NIOSH has all the details for the machine in the 1951–1957 period in the 

same table. Is there a contemporaneous reference that NIOSH used to determine the 

characteristics of the 1951–1957 machine? Is NIOSH certain that no photofluorography 

was done at NTS during the 1950s? 

2) NIOSH states that the SSD is smaller than the SID. The SSD was set at 183 cm, which 

corresponds to the SID in other TBDs. What is the justification for this variance? 

Occupational Environmental Exposure 

1) NIOSH has indicated that REECo established an environmental surveillance program in 

1964 designed to measure radiological conditions throughout the site without regard to 

nuclear tests. Has NIOSH/ORAU identified similar environmental monitoring programs 

prior to 1964? If so, where is this documented? (pg. 8) 

2) NIOSH has concluded that “unmonitored employees would not be likely to be exposed to 

freshly deposited radionuclides” (pg. 7). What is the basis for this assumption? Is there 

documentation that unmonitored employees did not enter radiologically sensitive areas 

shortly after tests? Has NIOSH verified this assumption by site expert and worker 

interviews? 

3) Were the glass fiber filters and later Whatman filters analyzed using wet or dry chemistry 

prior to 1971? (pg. 9) 

4) What is NIOSH/ORAU’s justification that those employees who were onsite 

continuously for weeks spent their nonworking hours indoors? (pg. 36) 

5) How is a dose reconstructor to assign environmental dose prior to the earliest years 

provided in environmental summary tables? Specifically, the table does not contain any 

entries prior to 1964. Some tables start in 1966; others start even later. 

6) How were the averages in Tables 4.2.1.2.2-1 calculated? Why were no data entered for 

some areas even though data were reported in the Environmental Report (e.g. Area 2 in 

CY 1996)? 

7) The TBD concluded that the bigger of the annual averages of environmental monitoring 

data and inferred air concentration using soil inventory data and resuspension should be 

used for inhalation dose assessment. In order to compare the two approaches, did NIOSH 

review the location of the air sampling stations with respect to the location of 

contaminated areas? 
Effective Date: 

December 13, 2005 

Revision No. 

0 

Document No. 

SCA-TR-TASK1-0006 

Page No. 

95 of 158 

8) The TBD states that the spatial variability of soil data is not a relevant issue because 

“radiological control practices would have prevented unmonitored employees from being 

inadvertently exposed in the more highly contaminated areas” (pg. 35). Where is this 

practice documented? 

9) The TBD recommends the use of an average for unmonitored workers where locations 

are not known (pg. 33). While area weighting was used, an alternative would be to 

assume equal presence at all areas. Why was area weighting assumed? Was area 

weighting based on area sizes that were sampled for the inventory estimates rather than 

based on the total size of the areas? 

10) Did NIOSH review the sampling efficiency of particulate samplers at high wind 

velocities with respect to the reliability of air monitoring and resuspension factors? 

11) Did NIOSH review the accuracy of HTO sampling at low humidity levels at NTS? 

12) Did NIOSH provide an analysis of I-131 releases from NTS after 1962 since internal 

I-131 exposures of non-monitored workers are not accounted for? 

13) The TBD states that it is “reasonable and probably claimant-favorable to assign 

maximum annual environmental doses for the years 1963 through 1966 equal to the 

maximum value reported for 1967 (i.e., 318 mrem yr-1).” Given other airborne releases 

from NTS in 1962 and 1965, can NIOSH provide measurements from NTS itself that 

corroborate this claim? 

14) NIOSH did not address inadvertent ingestion of soil as a pathway. Why was this 

excluded? 

15) The TBD states on page 35 “Although there were many radiation measurements 

completed between 1951 and 1967, most of these were to characterize the effects of 

weapons tests and were therefore not appropriate for use in estimating external 

environmental dose for unmonitored employees.” Which measurements were reviewed 

and where are they referenced? 

16) The TBD states on page 36 for external dose that the claimant-favorable maximum site 

value should be used if the area in which the employee worked is not known. In case of 

resuspension doses, the area-weighted average was used if the area in which the 

employee worked is not known. Why do the procedures differ in the two cases? 

17) With respect to the occupational dose to tunnel workers for radon, there is uncertainty 

with respect to the skin dose relative to a given lung tissue dose (see e.g., G.M. Kendall 

and T.J. Smith, “Doses to organs and tissues from radon and its decay products”, J. 

Radiol. Prot. 22 (2002) 389–406). How is uncertainty accounted for? 
Effective Date: 

December 13, 2005 

Revision No. 

0 

Document No. 

SCA-TR-TASK1-0006 

Page No. 

96 of 158 

Occupational Internal Exposure 

1) NIOSH indicated in the NTS TBD that several ingestion intakes occurred during cleanup 

activities at CLEANSLATE and DOUBLE TRACK. Where are the details of these 

ingestions documented? 

2) For what years was LANL responsible for the bioassay program at NTS? Which aspects 

of the program did LANL oversee? 

3) Are the radionuclides outlined in Table 3.1.1-2 of TIB-0002 used to determine the 

internal dose for nonmetabolic cancers? Why did NIOSH/ORAU not use the area or 

facility-specific radionuclides of concern, given the variability of radioactive 

constituents? 

4) It is unclear from the TBD what values were used for particle size, length of exposure, 

and breathing rate for internal dose calculation. Where is this information found? 

5) The TBD cites a reference to the effect that internal exposure data for E-Tunnel workers 

“were limited in both the quality and quantity needed for making reasonable accurate 

estimates of the intakes and doses.” (Vol. 5, pg. 69). How is NIOSH approaching this 

problem of E-Tunnel worker internal dose estimation? 

6) NIOSH has cited examples of ingestion dose (Vol. 2, pg. 21 and Vol. 5, pg. 69), but the 

TBD contains no model for estimating ingestion exposure. Does NIOSH consider that 

internal dose monitoring was sufficient to cover ingestion as well as inhalation? How is 

NIOSH partitioning between ingestion and inhalation in going back from bioassay data to 

intakes of radionuclides? 

Occupational External Exposure 

1) What type of beta/gamma dosimeter was used before 1961? Where is this information 

documented? 

2) What type of neutron dosimeter was used before 1966? Where is this information 

documented? 

3) NIOSH/ORAU has applied the Pantex neutron-to-photon ratios for NTS assembly 

workers. What is the basis for choosing the Pantex neutron-to-photon ratio? Were the 

weapons being assembled at the two facilities identical? 

4) The TBD is unclear regarding the direction provided to the dose reconstructor on 

assignment of external dose. Explain the process to be used by the dose reconstructor to 

calculate the dose under the following conditions: 

• 	 Individual has measured photon dose 

• 	 Individual has measured beta dose 
 

 

Effective Date: 

December 13, 2005 

Revision No. 

0 

Document No. 

SCA-TR-TASK1-0006 

Page No. 

97 of 158 

• 	 Individual has measured neutron dose 

• 	 Individual has no beta/gamma monitoring data 

• 	 Individual has no neutron monitoring data 

• 	 Individual has values below the detection limit of the particular dosimeter 

Please include comments on the adjustment factors, when missed doses are assigned, and 

the IREP input parameters (i.e., default radiation type and energy, and statistical 

methodology). 

5) Has NIOSH investigated dose from contact with contaminated water in the tunnels? 

6) Was there multiple badging of workers at NTS to allow for organ dose determination? If 

so, how is NIOSH using these data for estimating doses for workers with only one badge? 

If not, has NIOSH considered the problem of exposure geometry versus badge location in 

specific areas, such as hot spots, and specific jobs, such as re-entry workers (atmospheric 

and tunnel)? This issue turned out to be significant at IAAP, for instance, where NIOSH 

estimated that external pelvic area dose was 2.5 times the value recorded on the badge. 

7) The TBD states on page 17 that “background films” were used to zero the densitometer 

prior to reading a badge. What was the variability of the background film data and the 

densitometer reading itself? Is that uncertainty reflected in the bias factors and GSD for 

film badge data? 

8) The TBD states on page 12 that data from pocket ionization chambers (PIC) be used in 

case film badge results were not available. It is claimed that because of “typical 

overresponse characteristic”, use of PIC results is claimant favorable if no film badge 

data are available. Can NIOSH provide a comparison of PIC and film badge data? 

9) The TBD indicates the detection threshold for neutron energies for NTA film to be 

“about” 0.8 MeV, for TEDs “about” 100 keV. What is the uncertainty in the detection 

threshold, and how would a different detection threshold affect the bias factors? 

10) Section 6.3.2.2 (and subsections) contain statements that in other than neutron generator 

areas, “[n]eutron doses, for the most part, were low” (pg. 28). The TBD also states that 

neutron doses for unmonitored workers can be ignored because exposures were 

“unlikely” (pg. 28). There is little or no documentation cited as the technical basis for 

these judgments. Would NIOSH provide the references that are the basis for these 

conclusions? Has NIOSH interviewed site experts and workers in this regard? 
Effective Date: 

December 13, 2005 

Revision No. 

0 

Document No. 

SCA-TR-TASK1-0006 

Page No. 

98 of 158 

ATTACHMENT 2: ORAU WRITTEN RESPONSES TO SC&A QUESTIO

RK: As a general comment, SCA seems to be especially concerned with respect to ingestion and resuspension

contamination on the skin (e.g., their comment 35). These may be of concern because of the experience o

to the Marshall Islands, where they were the experts supporting the plaintiffs in litigation there, and in calthe Marshallese who were contaminated with fallout (as from BRAVO) and who lived on the contaminatThus, resuspension may be of interest because of their concerns about skin dose considerations from resusettling back down on the skin, or from a dose from a contaminated field, which were concerns from falloIslands (cf. Bravo shot). Similarly they are concerned about ingestion of soil because the Marshall Islandcontaminated area. The reviewers may not be particularly knowledgeable about operations at NTS as com

days of testing in the Pacific. 

CS: Some of these comments are Task 5 responsibilities, not Task 3. Resolutions provided by: GR = Gene Rollins RK = Ron Kathren VS = Vern Shockley LA = Lori Arent CS = Cheryl Smith RG = Richard Griffith (Griff is due back next week, 9/12 I believe) 

# Assigned to Comment Resolution 

General Comments 

1 Lori Gene Has NIOSH done worker and site expert interviews? If so, could NIOSH provide the minutes and notes of these interviews to SC&A as soon as possible? 

LA: NTS worker and site expert interviews have been includes references to personal communications and enecessary. Formal minutes were not prepared. GR: A list of site experts and former workers that werupon request. 
Effective Date: 

December 13, 2005 

Revision No. 

0 

Document No. 

SCA-TR-TASK1-0006 

Page No. 

99 of 158 

2 Cheryl Lori 

The TBD seems to emphasize the underground tests that occurred at NTS, while spending little time on the period of atmospheric testing. Does the statement in the introduction (TBD Vol. 1, pg. 7) that NIOSH is researching how to estimate dose from volatile radionuclides cover pathways of exposure? 

LA: The original direction was to prepare the NTS TBatmospheric testing. NTS TBD, Rev. 01 provides motesting era. CS: Pathways of exposure will be evaluated for imporreconstructor guidance in the process of being develo

3a Cheryl Lori 

Specifically in relation to atmospheric testing, is NIOSH considering internal dose pathways from activities, such as recovery of equipment, cleanup of debris, and other work assignments that may have occasioned entry into contaminated zones shortly after tests? Has NIOSH considered external and internal doses due to fallout from presence of workers outdoors 

during some atmospheric tests? Is NIOSH investigating the doses to health physics monitors who may have gone into the test areas for monitoring purposes shortly after the tests? 

LA: Dose reconstructors consider post-test activities idepending on job title and area of assignment. CS: The contractor acknowledged that anyone on site 

external exposure from testing. Those who directly pmonitored as stated in the safety report specific to the monitoring was limited at NTS. It is possible to assigLANL MDA values since LANL was responsible for and performed the analyses until 1958. Co-worker dais cost effective to do so for the period before all EEs 

3b Cheryl Lori 

In Vol. 2 (pg. 28), NIOSH notes that workers did re-enter test areas after the tests, and that this “had the potential to cause significant external and internal radiation exposures.” It is not clear from the context whether NIOSH is considering this in detail both for the atmospheric and underground testing periods. Would NIOSH clarify this? 

LA: Dose reconstructors consider all testing periods iTBD, Rev. 01 provides more details for the atmospheCS: This statement applies to deep underground testinhave been reviewed to this point, anyone involved in external and possibly internal dose reports (if an intakinformation is found in the access records and in the ireports which are provided by DOE. These records arreconstruction. For atmospheric testing, the individuaspecific information on re-entry which is available to 

3c Gene 

What is the state of the research in characterizing this exposure potential other than the resuspension estimation? Vol. 6 (pg. 38) on external dose, for instance, cites three references for external dose for re-entry personnel, but two refer to general articles for fission product spectra and one is a personal communication. Are there site-specific data for the statements regarding the claimantfavorable approach to dose estimation discussed in the paragraph just above Section 6.3.4.2? 

GR: The best source of site-specific information regarradionuclides in fallout at various times after detonati

written by Harry G. Hicks of the Lawrence Livermore 1961 to 1981. These papers were reviewed in detail arequest. CS: The revision to the TBD external section includes ranges based on the radionuclides present at NTS. 

4 Lori Cheryl 

What areas of NTS are associated with AEC/DOE operations alone? How has NIOSH segregated exposure between DOE and DOD operations, or have they assumed all radioactive exposure was a result of AEC/DOE activities? Specifically, has NIOSH investigated whether any AEC, or AEC contractor or subcontractor personnel participated with armed forces personnel in the exercises at NTS? 

LA: DOD atmospheric and underground nuclear tests the laboratories (i.e., SNL, LLNL, LASL) in multiple assumed radioactive exposure was a result of AEC/DOcontractor personnel provided support (e.g., air samplCS: Any identified activity w/i the EE's confirmed emexpressly omitted is evaluated in the dose of record. 
Effective Date: 

December 13, 2005 

Revision No. 

0 

Document No. 

SCA-TR-TASK1-0006 

Page No. 

100 of 158 

Table 2-2 in the site description lists no radionuclides of concern for Areas 3 & 11, the Nuclear Explosive Assembly Area (Area 

5 Lori 27), and the Device Assembly Area (Area 6). Is this an oversight on the part of the TBD author or is NIOSH/ORAU indicating that 

there were no radiation exposures in these areas? Are there any area or personnel exposure records for these areas? 

LA: Table 2-2 has been revised to include radionuclidareas. There are personal and area exposure records f

Occupational Medical Comments 

6 Vern Ron 

Who performed diagnostic x-ray inspections at NTS? Was the State of Nevada involved in this? Why was NIOSH not able to determine the machine type and factors used in diagnostic x-rays after 1957 and even as late as 2002 (Table 3-4, Vol. 3, of the TBD)? By contrast, NIOSH has all the details for the machine in the 1951–1957 period in the same table. Is there a 

contemporaneous reference that NIOSH used to determine the characteristics of the 1951–1957 machine? Is NIOSH certain that 

no photofluorography was done at NTS during the 1950s? 

VS/RK: Diagnostic x-ray beam measurements were mindicated by the references. Documentation on the tyused subsequent to 1957 have not been located; howeinasmuch as measurement of the ESE is available. Thanecdotal information that suggests that PFG was carr

7 Vern Ron NIOSH states that the SSD is smaller than the SID. The SSD was set at 183 cm, which corresponds to the SID in other TBDs. What is the justification for this variance? 

VS/RK: The text is correct as written. Section 3.2.3 s

inches (= 183 cm) and that the SSD was “somewhat sof chest thickness later in the section, as well as in mu0006. Further, the variation in SSD is discussed in the both SID and SSD are defined in the glossary. The co

Table 3.4, which gives the Source to Skin Distance as incorrect and should be SID (Source to Image Distanc

Environmental Comments 

GR: Numerous Safety reports prior to 1964 were reviconsisted primarily of radiation readings at various di

8 Gene 

NIOSH has indicated that REECo established an environmental surveillance program in 1964 designed to measure radiological conditions throughout the site without regard to nuclear tests. Has NIOSH/ORAU identified similar environmental monitoring programs prior to 1964? If so, where is this documented? (pg. 8) 

These data did not include any onsite information that 

unaffected areas (i.e., background). To date, no basel

onsite have been identified prior to 1964. VS: The offsite environmental monitoring program at the USPHS in Las Vegas. This data on the offsite envhave been documented in their Las Vegas facility and the start of their program. REECo also conducted env
Effective Date: 

December 13, 2005 

Revision No. 

0 

Document No. 

SCA-TR-TASK1-0006 

Page No. 

101 of 158 

9 Gene Ron 

NIOSH has concluded that “unmonitored employees would not be likely to be exposed to freshly deposited radionuclides” (pg. 7). 

What is the basis for this assumption? Is there documentation that unmonitored employees did not enter radiologically sensitive areas shortly after tests? Has NIOSH verified this assumption by site expert and worker interviews? 

GR: An extensive review of the radiological safety rerevealed detailed instructions related to posting and encontaminated after detonations. These regulations reqentry controls through manned checkpoints for areas wexcess of 10 mR/hr. Entry into these areas was contrologs and all individuals entering these areas were monpocket ionization dosimeters. Upon exit from these aalso monitored for contamination. With these regulatunlikely that an unmonitored employee would be allocontamination area. With regard to documentation, it documentation would exist that proved that something 

experts have been contacted to verify that the radiologimplemented and complied with. VS/RK: Unmonitored employees -- i.e., employees w

- did not have access to radiation areas, or even to the considerations limited access to unbadged people. Acsecurity badge and a dosimeter, plus training as a rad-radiologically controlled areas. 

10 Gene Ron Were the glass fiber filters and later Whatman filters analyzed using wet or dry chemistry prior to 1971? (pg. 9) 

GR: Prior to 1971, particulate air samples were analyzby gas proportional counting. During this same perioperformed using Na(TI) detectors. All of these analydirect counting of dry filter papers. Records indicate start until 1971 when radiochemical analysis for plutoVS/RK: Standard practice was to count the filters dry chemistry especially on fiber glass filters. 

11 Gene Ron What is NIOSH/ORAU’s justification that those employees who were onsite continuously for weeks spent their nonworking hours indoors? (pg. 36) 

GR: It is well documented through interviews with wgained through the CATI interviews that NTS employthan 8 hours per shift (typical shifts were 10–12 hoursduty, it is presumed that they did not have their meals hours/day) nor did they sleep outdoors (~ 8 hours per activities leaves only a couple of hours when they cououtdoors during nonworking hours. VS/RK: Most nonwork activities -- e.g., Sleeping, eawere indoors. Other activities, softball, volleyball, etcbackground areas. These areas were monitored by arefor dose determination, if not registered on their film probably wearing. 
Effective Date: 

December 13, 2005 

Revision No. 

0 

Document No. 

SCA-TR-TASK1-0006 

Page No. 

102 of 158 

12 Gene Cheryl 

How is a dose reconstructor to assign environmental dose prior to the earliest years provided in environmental summary tables? Specifically, the table does not contain any entries prior to 1964. Some tables start in 1966; others start even later. 

GR: The assignment of environmental external dose f

during the atmospheric testing phase at the NTS has nCS: This determination will be made based on how thdosimeters were handled during this period. Dose rec1966 data back to 1963 based on project guidance. 

13 Gene 

How were the averages in Tables 4.2.1.2.2-1 calculated? Why were no data entered for some areas even though data were reported in the Environmental Report (e.g. Area 2 in CY 1996)? 

GR: These values represent arithmetic averages of the of the areas. It is agreed that data was provided for 19in the table. A review for missing data will be performto assure that all available data is included in the table

14 Gene 

The TBD concluded that the bigger of the annual averages of environmental monitoring data and inferred air concentration using soil inventory data and resuspension should be used for inhalation dose assessment. In order to compare the two approaches, did NIOSH review the location of the air sampling stations with respect to the location of contaminated areas? 

GR: As stated in the TBD, the resuspension model (Apredict atmospheric concentrations of plutonium was empirical measurements made at the NTS starting as e

consisted of comparisons of soil concentrations to meconcentrations. The relative agreement (usually withimeasured data (i.e., Tables 4.2.1.2.2-1 and 4.2.1.2.2-2(Table 4.2.2-2) verifies the applicability of the modelfavorable assumptions used with the resuspension mothat the derived intakes will exceed the intakes derivean instance where this is not the case (e.g., Area 9, 19documentation that the EE spent the majority of their outdoor environment before the higher measured valu

15 Gene 

The TBD states that the spatial variability of soil data is not a relevant issue because “radiological control practices would have 

prevented unmonitored employees from being inadvertently exposed in the more highly contaminated areas.” (pg. 35) Where is this practice documented? 

GR: Please see response to comment 9 above. VS/RK: A personnel monitor and a security badge wecontaminated areas. Entry was controlled by site secunon-badged personnel the NTS controlled area. 

16 Gene 

The TBD recommends the use of an average for unmonitored workers where locations are not known (pg. 33). While area 

weighting was used, an alternative would be to assume equal presence at all areas. Why was area weighting assumed? Was area weighting based on area sizes that were sampled for the inventory estimates rather than based on the total size of the areas? 

GR: Using the site average values is the same as assumareas. The extensive soil surveys that were conducted 1983, 1985, 1987, 1988, 1989, 1991) consisted of thomeasurements taken from many locations within the cdata were used to estimate total inventories (by Area) radionuclides. The values provided in Table 4.2.2-1 ainventory divided by the total Area size. 

17 Gene 

Did NIOSH review the sampling efficiency of particulate samplers at high wind velocities with respect to the reliability of air monitoring and resuspension factors? 

GR: No. The relative agreement of the predicted valualong with the claimant-favorable assumptions used in provide reasonable assurance that the predicted intake actual intakes. 

18 Gene Did NIOSH review the accuracy of HTO sampling at low humidity levels at NTS? GR: No. The samplers contained a catalytic converte

to tritium oxide which was then trapped in a column o
Effective Date: 

December 13, 2005 

Revision No. 

0 

Document No. 

SCA-TR-TASK1-0006 

Page No. 

103 of 158 

19 Gene Cheryl Did NIOSH provide an analysis of I-131 releases from NTS after 1962 since internal I-131 exposures of non-monitored workers are not accounted for? 

GR: There were 10 underground tests that resulted in unanticipated significant atmospheric releases after A

documented in Chapter 2 and in the limitations that prTo date, no analysis of radioiodine releases that occurperformed. CS: This will be done on an as-needed basis by the dothe infomation provided in Chapter 5. Additional dethas been included in Rev. 01 of Chapter 5. 

20 Gene 

The TBD states that it is “reasonable and probably claimantfavorable to assign maximum annual environmental doses for the years 1963 through 1966 equal to the maximum value reported for 1967 (i.e., 318 mrem yr-1).” Given other airborne releases from NTS in 1962 and 1965, can NIOSH provide measurements from NTS itself that corroborate this claim? 

The value of 318 mrem was based on the maximum aany area in 1967. As stated in the TBD, this value wameasure reported for the entire site for that year. Thewith certainty, it seemed appropriate to use this value period from 1963 through 1966 because, in reality, emlocated 100% of the time at the location of highest radcould be increased if deemed appropriate. 

21 Gene NIOSH did not address inadvertent ingestion of soil as a pathway. Why was this excluded? 

GR: Inadvertent ingestion of soil has typically not beepathway for exposure when compared to direct exposAn evaluation was performed that showed ingestion oat the NTS (i.e., 100,000 Bq/m2 over a 10 cm depth, T

accepted ingestion rate for workers of 50 mg/day (RAannual dose to any organ from any radionuclide of muyear. Doses of this magnitude are typically not includTherefore, the inclusion of annual dose resulting from deemed to be important for purposes of dose reconstru

22 Gene 

The TBD states on page 35 “Although there were many radiation measurements completed between 1951 and 1967, most of these were to characterize the effects of weapons tests and were therefore not appropriate for use in estimating external environmental dose for unmonitored employees.” Which measurements were reviewed and where are they referenced? 

GR: These data are summarized in a series of 19 Radiwere produced from 1951 through 1966. These reporradiological data for all tests conducted in a given yeaon a daily basis after each test and used to determine twhere control points were set up to control access. D“downwind” locations including many offsite locationpossible to determine with any certainty which of the have represented radiation levels essentially unaffecteRadiological Safety reports have not been cited in the them was not used. However, the citations can be add

23 Gene 

The TBD states on page 36 for external dose that the claimantfavorable maximum site value should be used if the area in which the employee worked is not known. In case of resuspension doses, the area-weighted average was used if the area in which the employee worked is not known. Why do the procedures differ in the two cases? 

GR: In each case, the recommendation favors the clairesponse to Comment 10 above, the claimant-favorabresuspension will result in intakes that are, with few ederived from the measured data. Likewise, using the rate will always result in the highest dose assignment 
Effective Date: 

December 13, 2005 

Revision No. 

0 

Document No. 

SCA-TR-TASK1-0006 

Page No. 

104 of 158 

24 Gene 

With respect to the occupational dose to tunnel workers for radon, there is uncertainty with respect to the skin dose relative to a given lung tissue dose (see e.g. GM Kendall and T J Smith, “Doses to organs and tissues from radon and its decay products”, J. Radiol. Prot. 22 (2002) 389–406). How is uncertainty accounted for? 

GR: To date, NIOSH has limited dose reconstruction the lung and ET1 and ET2 regions. Therefore, contribskin dose from exposure to radon has not been considVS/RK: Generally, workers in tunnels were provided and also work protective clothing. These workers wethe REECo RadSafe Monitors. They also wore their if airborne radioactivity was suspected continous air s

Internal Comments 

25 Lori 

NIOSH indicated in the NTS TBD that several ingestion intakes occurred during cleanup activities at CLEANSLATE and 

DOUBLE TRACK. Where are the details of these ingestions documented? 

LA: The summary report that includes the Double Tra

239Pu, June 1995) prepared by an independent investigNTS TBD (French & Scrable, 1995). The site contracof the occurrences in internal reports. 

26 Lori For what years was LANL responsible for the bioassay program at NTS? Which aspects of the program did LANL oversee? LA: LANL was responsible for the program and perfo

1955 to 1958 when the REECo radioanalytical labora

27 Cheryl 

Are the radionuclides outlined in Table 3.1.1-2 of TIB-0002 used to determine the internal dose for nonmetabolic cancers? Why did NIOSH/ORAU not use the area or facility specific radionuclides of concern, given the variability of radioactive constituents? 

CS: Several techniques have been developed for assigspecific guidance has not been developed for the atmoDose reconstructors are permitted to use ORAUT (OaUniversities Team) guidance (i.e., ORAUT-OTIB-2, OORAUT-OTIB-18 within their stated limitations) for 

28 Lori 

It is unclear from the TBD what values were used for particle size, length of exposure, and breathing rate for internal dose 

calculation. Where is this information found? 

LA/CS: The default values for particle size and breathdose reconstruction are from the Internal ImplementatThe length of exposure is determined by the Dose Recthe description of the NTS bioassay program in Chapt

29 Lori 

The TBD cites a reference to the effect that internal exposure data for E-Tunnel workers “were limited in both the quality and quantity needed for making reasonable accurate estimates of the intakes and doses.” (Vol. 5, pg. 69). How is NIOSH approaching this problem of E-Tunnel worker internal dose estimation? 

LA: The summary report that includes the E Tunnel in

June to August 1994) prepared by an independent invNTS TBD (French & Scrable, 1995). The site contracof the occurrences in internal reports. 
Effective Date: 

December 13, 2005 

Revision No. 

0 

Document No. 

SCA-TR-TASK1-0006 

Page No. 

105 of 158 

CS: For those workers where the dose reconstructor denvironmental dose can be applied, ingestion is includperforming internal dose evaluations, inhalation has b

30 Cheryl 

NIOSH has cited examples of ingestion dose (Vol. 2, pg. 21 and Vol. 5, pg. 69), but the TBD contains no model for estimating ingestion exposure. Does NIOSH consider that internal dose monitoring was sufficient to cover ingestion as well as inhalation? How is NIOSH partitioning between ingestion and inhalation in going back from bioassay data to intakes of radionuclides? 

factor and is the pathway evaluated when using IMBA#ORAUT-OTIB-0018, Internal Dose Overestimates f

Sampling Programs, Rev 01, August 9, 2005 can be aingestion/resuspension is included in this model. VS: I don't know why there is so much emphasis on inworking there, we were very careful that we did not eareas without adequate protection, full Anti-Cs and reduring high winds we did not enter these areas. Weatactivities in the flats. All testing was controlled by th

External Comments 

31 

Griff 

Ron 

Cheryl 

What type of beta/gamma dosimeter was used before 1961? Where is this information documented? 

RK: The NTS film badge was changed to a multi-elembadge used prior to 1966 is described in both the text CS: Chapter 6, Rev. 01 will include dosimetry inform

32 Griff Ron What type of neutron dosimeter was used before 1966? Where is this information documented? RK: As indicated in both text and table, neutron dosim

1966. 

33 Griff Ron 

NIOSH/ORAU has applied the Pantex neutron-to-photon ratios for NTS assembly workers. What is the basis for choosing the Pantex neutron-to-photon ratio? Were the weapons being assembled at the two facilities identical? 

RK: Given the basic design and materials involved, as reasonable to assume that the Pantex ratios are appropreports of studies of neturon and gamma doses from wCS: Pantex TBD is in draft. LA Chapter 6, Rev. 01 st

1960, if neutron dose information is not specifically awith final assembly and arming operations, photon exneutron-to-photon dose ratios can be used. The neutrderived from the experience at Pantex where weapons conducted. Analysis of dose records for each Pantex neutron dose greater than 50 mrem for the period 199mean of 0.81 and GSD of 1.51. An upper 95th-percenused for the neutron-to-photon dose ratio (ORAU 200Plant TBD). 
Effective Date: 

December 13, 2005 

Revision No. 

0 

Document No. 

SCA-TR-TASK1-0006 

Page No. 

106 of 158 

34 Cheryl 

The TBD is unclear regarding the direction provided to the dose reconstructor on assignment of external dose. Explain the process to be used by the dose reconstructor to calculate the dose under the following conditions: • Individual has measured photon dose • Individual has measured beta dose • Individual has measured neutron dose • Individual has no beta/gamma monitoring data • Individual has no neutron monitoring data • Individual has values below the detection limit of the particular 

dosimeter. Please include comments on the adjustment factors, when missed doses are assigned, and the IREP input parameters (i.e., default radiation type and energy, and statistical methodology). 

CS: General project guidance for assigning dose is fo• NIOSH, (2002) External Dose Reconstruction Imple

OCAS-IG-001, National Institute for Occupational SaCompensation Analysis and Support, Cincinnati, Ohi• ORAUT (Oak Ridge Associated Universities Team)External Dose Reconstruction, Rev 00 PC-2, Decembphoton, electron and neutron radiation types. Beta dose is evaluated consistent with • ORAUT (Oak Ridge Associated Universities Team)Technical Information Bulletin: Interpretation of Dosof Shallow Dose, Rev 00, January 19, 2005. After 4/1/57, all EEs entering the site were assigned ddosimeters were not read for the beta/electron compon

and other means of estimating beta/electron dose are b
Effective Date: 

December 13, 2005 

Revision No. 

0 

Document No. 

SCA-TR-TASK1-0006 

Page No. 

107 of 158 

34 Continued 

For an individual with no neutron bioassay, ORAUT Universities Team), ORAUT-OTIB-0023, Technical I

Assignment of Missed Neutron Doses Based on DosimMarch 7, 2005; Chapter 6, Section 6.3.2.2; and the recthe EE would be reviewed to determine the appropriaFor values below the detection limit of the particular dbe applied as missed dose. This is consistent with • NIOSH, (2002) External Dose Reconstruction ImpleOCAS-IG-001, National Institute for Occupational SaCompensation Analysis and Support, Cincinnati, Ohio • ORAUT (Oak Ridge Associated Universities Team)External Dose Reconstruction, Rev 00 PC-2, DecembUncertainty factor of 1.3 has been applied to doses as information in Section 6.3. This is consistent with the for uncertainty. Table 6-8 provides further informatioCurrently maximizing photon dose is 100% 30–250 k30–250 keV and 75% >250keV. Further discriminatiranges is included in the Rev. 1 of Chapter 6 of the TBStatistical methodology is contained in project guidanabove cited documents and additionally • ORAUT (Oak Ridge Associated Universities Team)Technical Information Bulletin: Monte Carlo MethodCalculations, Rev 00, February 14, 2005; • ORAUT (Oak Ridge Associated Universities Team)Technical Information Bulletin: Use of Coworker DoDose Assignment, Rev 00, December 29, 2004 VS: Co-worker procedures should cover this area and values that are claimant favorable. 

35 Griff Has NIOSH investigated dose from contact with contaminated water in the tunnels? CS: In 1961, there was a tritium exposure incident in 

reported in Chapter 5. 

36 Griff Ron 

Was there multiple badging of workers at NTS to allow for organ dose determination? If so, how is NIOSH using these data for 

estimating doses for workers with only one badge? If not, has NIOSH considered the problem of exposure geometry versus badge location in specific areas, such as hot spots, and specific jobs, such as re-entry workers (atmospheric and tunnel)? This issue turned out to be significant at IAAP, for instance, where NIOSH estimated that external pelvic area dose was 2.5 times the value recorded on the badge. 

RK/CS: Multiple organ badging was typically not donstandard industry practice. Organ doses can be deriveusing standard techniques. In the absence of documen

exposure geometry, the badge data should prove adeqgeometries require specific individual evaluations; hoguidance will be applied. 
Effective Date: 

December 13, 2005 

Revision No. 

0 

Document No. 

SCA-TR-TASK1-0006 

Page No. 

108 of 158 

37 Griff Ron 

The TBD states on page 17 that “background films” were used to zero the densitometer prior to reading a badge. What was the variability of the background film data and the densitometer reading itself? Is that uncertainty reflected in the bias factors and GSD for film badge data? 

RK: The practice at NTS was consistent with standard 

The variability of background data within a film lot ovariation from batch to batch is likewise small. Typicbatch was issued. Any effect of background fog on bwould have no effect on dose estimation. 

38 Griff Ron 

The TBD states on page 12 that data from pocket ionization chambers (PIC) be used in case film badge results were not available. It is claimed that because of “typical overresponse characteristic”, use of PIC results is claimant favorable if no film badge data are available. Can NIOSH provide a comparison of PIC and film badge data? 

RK: The energy dependence of the film badge was chthe Pb filter, energy response was essentially flat abovknown at the time, and published in numerous studies construction of the PICs which had a high Z wall relaPICs were notoriously energy dependent for photon e200 keV, showing a large overresponse relative to tissNuclear Radiation Detection, McGraw-Hill, 1958, pg3rd ed., pp. 89–90, App. O and LA-2679). There is nand film badge data at NTS. 

39 Griff Ron 

The TBD indicates the detection threshold for neutron energies for NTA film to be “about” 0.8 MeV, for TEDs “about” 100 keV. What is the uncertainty in the detection threshold, and how would a different detection threshold affect the bias factors? 

RK: The first sentence in this question is not understo“about” 100 keV”? Certainly a shift in the neutron encould affect the calibration (i.e., bias) factor of the NTspectrum. However, far more significant from the staneutron spectrum itself which is highly variable, the aneutrons as a function of energy, and latent image fad

40 Griff Vern 

Section 6.3.2.2 (and subsections) contain statements that in other than neutron generator areas, “[n]eutron doses, for the most part, were low” (pg. 28). The TBD also states that neutron doses for unmonitored workers can be ignored because exposures were “unlikely” (pg. 28). There is little or no documentation cited as the technical basis for these judgments. Would NIOSH provide the references that are the basis for these conclusions? Has NIOSH interviewed site experts and workers in this regard? 

CS: ORAUT-OTIB-23 provides guidance on assigninrecords reviewed to date have included limited positivneutrons. VS: NTS site experts and workers have been interviewwere in high security areas and controlled. Unmonitoaccess to these areas as they were under security's conmisunderstanding of how neutron generators were usesensitive area. There is more than 20 years of site expdeveloping these TBDs. Some of the authors worked equipment. 
 

Effective Date: 

December 13, 2005 

Revision No. 

0 

Document No. 

SCA-TR-TASK1-0006 

Page No. 

109 of 158 

ATTACHMENT 3: SUMMARY OF CONFERENCE CALL ON 

SEPTEMBER 9, 2005 

Summary of September 9, 2005, Conference Call Regarding SC&A Questions Sent to NIOSH 

on May 6, 2005. The questions sent by SC&A to NIOSH are in Attachment 1. Written ORAU 

Responses are in Attachment 2. This summary of the conference call complements the written 

responses in Attachment 2. 

Present on the September 9, 2005 call: 

NIOSH: Mark Rolfes 

ORAU and ORAU subcontractors: Judson Kenoyer, Gene Rollins, Cheryl Smith, 

SC&A: John Mauro, Hans Behling, Arjun Makhijani, John Hunt, Tom Bell 

In the following summary the term “NIOSH” refers to NIOSH, ORAU, or ORAU 

subcontractors. 

NIOSH stated that Richard Griffith, Ron Kathren, and Vern Shockley could not be on the call 

due to other commitments, but they are all valuable resources for questions in their areas of 

expertise. 

NIOSH Worker and Site Expert Interviews 

NOISH had extensive interchanges with site experts by telephone, e-mail, and numerous site 

visits. The closest communication was with Martha DeMarre, Manager, Nuclear Testing 

Archive, Coordination and Information Center. Phone communication with her and external and 

internal dosimetrists was pretty much on a daily basis during the preparation of the TBD. 

NIOSH also talked to retired workers. There are informal notes of communications as well as 

e-mails. The e-mails and notes that were used in the site profile were cited as references and are 

available. They are listed as personal communications and were documented. They are in the 

CD that was sent to the documents section to be archived. They can be retrieved and sent to 

SC&A. The referenced communications are on the O drive [which is the main NIOSH document 

database]. There is a CD of references for every chapter of the TBD. [A list of contacts made by 

NIOSH with NTS personnel is shown in Annex A to this Attachment.] 

Not all points made during the exchanges were documented or summarized. NIOSH only 

documented points that it considered useful. 

It was not clear during the call whether NIOSH had interviewed William J. Brady, who worked 

at NTS from 1952 to 1991, when he retired as Principal Health Physicist. [Post-call clarification: 

Richard Griffith, NIOSH contractor, interviewed Mr. Brady on February 27, 2004, regarding 

neutron exposure and on April 15, 2004, regarding photon exposure. A summary of the contacts 

is shown in Annex B of this Attachment.] [SC&A’s interview with Mr. Brady is in 

Attachment 5.] 
Effective Date: 

December 13, 2005 

Revision No. 

0 

Document No. 

SCA-TR-TASK1-0006 

Page No. 

110 of 158 

There were no declassification delays in the interview process. A declassification officer was 

involved in the review of the various sections of the TBD. Although she only attended one of 

our meetings for the day, she reviewed all of the TBD chapters prior to dissemination. 

The notes of the site-expert and retired-worker communications are scattered. It would take 

some time to pull them out. There is no organized summary of the interchanges. Notes of site 

expert interviews that were used in Volume 2 and Volume 4 of the TBD are immediately 

available. 

SC&A requested the notes of interviews, the notes of the interview with William Brady if it was 

done, other records interviews, and e-mails, whether or not these notes and e-mails were used in 

the preparation of the TBD, by 22 September 2005. The deadline for final completion of SC&A 

review was a few days after that. 

Status of Revision 1 of the TBD 

Through the written response provided to the questions (see Attachment 2) on September 8, 

2005, SC&A learned that NIOSH was preparing Revision 1 of the TBD. 

In response to the SC&A question about the status of Rev. 01 during the conference call, NIOSH 

stated that it is still working through the approach document for internal dose during atmospheric 

testing. The issues on this point are not resolved yet and are at the contractor level still. NIOSH 

is aware of the problem and is exploring various options for assigning internal dose during the 

atmospheric testing era. Revisions of other chapters are essentially complete and could be 

released. They have been edited and formatted. NIOSH is close to issuing revisions to all 

chapters except Chapter 1. [The person responsible for Chapter 1 could not be on the call.] 

Chapter 1 will be revised, as necessary, to reflect the content of most recent revisions of the other 

chapters of the TBD. The actual timing of the release of Rev. 01 will depend on the time 

required to resolve outstanding issues with OCAS. 

SC&A noted that its review was of Rev. 00, while NIOSH was ready to issue Rev. 01 at about 

the same time as the SC&A review of the prior document. NIOSH stated that Rev. 00 was to 

provide guidance for dose reconstruction from 1963 onward. SC&A stated that it would 

acknowledge that Rev. 01 is in the works in its introduction, and specifically note that Rev. 01 

would contain dose reconstruction information on the atmospheric testing period. SC&A noted 

that its review will contain some evaluation of issues relating to the atmospheric testing period 

that emerged as part of its overall review of NTS dose reconstruction questions. 

Contractors and Subcontractors 

SC&A noted that Mr. Brady had estimated in his interview that there were 800 subcontractors at 

NTS over the years and asked how many had been identified. 

NIOSH stated that the total of 800 included all kinds of contractors small and big, including 

those who did tasks like mixing cement [which Mr. Brady had also said in his interview – see 

Attachment 5]. For instance there was someone on site for 34 days and he had 33 badges. He is 
Effective Date: 

December 13, 2005 

Revision No. 

0 

Document No. 

SCA-TR-TASK1-0006 

Page No. 

111 of 158 

a claimant. NIOSH wanted job titles and NTS has put that list together along with a short list of 

prime contractors. Martha DeMarre has identified the main contractors. The job title and major 

contractor list is included in NTS TBD Chapter 2, Rev. 01. 

The integrated ID and film badge was introduced in 1966. There is a clear record of access to 

the site along with film badge records after that. The film was replaced by the TLD in 1987. 

Details of dosimeter history are in Table 6.1 of the TBD. 

In regard to whether doses were received by NTS personnel when they went to other sites, such 

as for the New Mexico plowshares test, NIOSH stated that the records of all workers employed 

at NTS (primarily by REECo) are complete. The issue is rather the other way, as to whether 

there is double counting of doses for people who came to NTS from Los Alamos or Livermore. 

There will be a section on this issue in Chapter 6 of Rev. 01 of the NTS TBD. SC&A noted that 

there may be a period for which the records of Sandia personnel at NTS are not complete in the 

NTS archive. This is not expected to affect NTS employees’ dose reconstruction. 

Some Atmospheric Testing Issues 

There was apparently no internal dosimetry until 1955 or 1956 when Los Alamos did some 

plutonium bioassay. NIOSH has not seen any internal data prior to this time in doing its NTS 

dose reconstructions. There does not appear to be a list of people who were monitored for 

internal dose at the time; Martha DeMarre has said that the most likely people were the people 

from Wackenhut, but there are no positive bioassay results. To date the records reviewed during 

dose reconstruction for this group (security guards) have provided no positive bioassay. SC&A 

raised questions about the quality and quantity of data – i.e., frequency of sampling, cross 

contamination, etc. Many workers were not exposed to situations with potential for intakes of 

radionuclides. Other workers went in and scraped the glassy radioactive matrices formed due to 

the tests. NIOSH proposes to assign Los Alamos minimum detectable amounts to workers in 

this period. Also for external dose, NTS TBD Table 6-1 has been expanded to include the 

specific LODs for the various operations prior to 1963. There are still outstanding issues. 

One opinion put forth by NIOSH was that external dose monitoring was not required until 1957, 

and is not complete in the period up to that time. One of the dose reconstructors stated that 

badges were provided to everyone after the April 1, 1957. There were no NTS tests from 

January 18, 1956 (Project 56, NTS Area 11), to April 24, 1957 (Project 57, Pu dispersal tests), 

conducted on the Nellis Air Force Range, which is contiguous to NTS and which used the same 

population of workers. The first NTS Test in 1957 was May 28, 1957 (NTS, Area 7, tower test, 

BOLTZMANN, Operation Plumbbob). From then on the external dose record was pretty good. 

Prior to that time there are some numbers, but they are of people involved in the test. Others like 

those at Camp 12, housekeepers who changed beds, etc., were not badged before 1957. 

SC&A raised the question of the relative exposure potential during the atmospheric testing 

period compared to the underground testing period. NIOSH stated that exposures during the 

atmospheric testing period for workers may not be higher than during the underground testing 

period because the wind carried away most material after atmospheric tests, while it remained 
Effective Date: 

December 13, 2005 

Revision No. 

0 

Document No. 

SCA-TR-TASK1-0006 

Page No. 

112 of 158 

underground after underground tests. In that light, people offsite may have received higher doses 

than onsite personnel during the atmospheric testing period. 

SC&A raised the question of determining the time of entry into ground zero after the test. 

NIOSH stated that that was a difficult question for the early period. There are operations records 

for events that could be matched with the personnel records to determine when people were 

signed in and out of the barricaded areas. There are isopleths of radiation levels in the early time 

frame, but they are not very helpful in determining dose. During the atmospheric testing period, 

Rad Safe personnel entered ahead of the marines to monitor radiation levels. Laborers and other 

crafts entering the area after an atmospheric test occurred were provided radiological support. 

SC&A noted that there are a lot of data for armed forces personnel that SAIC has and that they 

may be a useful source for dose reconstruction for civilian personnel. ORAU personnel 

responded that ORAU had approached SAIC, but that access to the data was denied, apparently 

for the reason that the data were generated for a specific client (presumably the Department of 

Defense), and therefore that it was not appropriate to share it with another client. SC&A noted 

that some records might be public and even be available on the DTRA [Defense Threat 

Reduction Agency] web site. NIOSH states that some of those records are in its archive on its 

“O drive.” 

As regards access time after underground tests, it could vary from a day to a couple of weeks. 

That is documented in the access records. For reactor tests, access was as close as they could 

access the site after shutdown of the reactor test, depending on the purpose of the test. Recently 

Task 5 [the ORAU Dose Reconstruction task] was looking for re-entry information on a specific 

reactor test. We were informed that NTS did not have the reports that might contain that 

information. The responsible site (LLNL in this case) would need to be contacted. 

Occupational Medical Exposure 

There was a general discussion of how to deal with the issue of PFG when there was no evidence 

of its use. In the case of NTS, NIOSH has found no evidence of PFG. In response to an SC&A 

question about the size of the x-ray plates, NIOSH stated that only a record of the list of x-rays 

that was done was provided. X-ray information is not included in all DOE files. When provided 

the record, in most cases only the name of the person and the type of x-ray that was done were 

given [in terms of the medical aspects, not the type of machine that was used]. 

SC&A noted that the issue of PFG in the early period (up to 1970) was a recurring theme in 

reviews. According to NIOSH’s general procedure, specified in a technical information bulletin 

(ORAUT-OTIB-0006), one of the default assumptions is an annual exposure from PFG, to be 

applied when there is no positive indication of equipment that was used. The application of this 

seems to be inconsistent. Sometimes when there is no evidence, the TBD advises use of PFG; in 

other cases it does not. In the case of NTS, there is no information on equipment even after 

1957, though NIOSH has done an extensive search of the records for this. But the TBD does not 

recommend assumption of PFGs through 1970. Rather it assumes use of x-ray film throughout. 

SC&A noted that this could make a big difference because PFG doses are ~3 rem per procedure. 

SC&A also pointed out that the dose assumptions for PFG procedures are not consistent between 
Effective Date: 

December 13, 2005 

Revision No. 

0 

Document No. 

SCA-TR-TASK1-0006 

Page No. 

113 of 158 

TBDs, which do not always use 3 rem as the default dose. NIOSH stated that the question could 

not be addressed on the call since the person who has investigated those issues, Ron Kathren, 

was not on the call. 

SC&A has looked at the issue of dose per PFG procedure and concluded that 3 rem is very 

claimant favorable for an average value. So the issue is not the average value, but the 

uncertainty. The factor of 1.3 for uncertainty is a one-sigma value and so does not represent a 

95th percentile value for the dose. SC&A recognizes that this is a generic issue, but it does affect 

specific sites and dose reconstructions and so should be taken into account. 

Occupational Environmental Exposure 

SC&A noted that the average contamination levels may not reflect working conditions for 

individuals. It seems that in-situ surveys only covered about 10% of the affected area. A review 

of the isopleths in the McArthur report indicates that area-wide average values may have 

underestimated soil concentrations, especially when testing areas were close together or tests 

were done in the same area within a short time of one another. 

NIOSH responded that the dose calculation assumed an exposure time of 2,600 hours. Since 

workers would not spend all their time in highly contaminated areas, this approach was 

appropriate since NIOSH would not be significantly underestimating the intake. Further, all 

personnel were badged after 1957. NIOSH also assumes an extra factor of ten for resuspension 

above the average value when estimating internal environmental doses. 

SC&A raised the issue of why NIOSH had chosen to use a resuspension approach, rather than a 

mass loading, for times long after the tests. NIOSH responded that the resuspension model 

overestimates dose when compared with on site measurements. 

SC&A raised two points in response to this question. First, the main reference cited in the TBD 

for the resuspension factors, Anspaugh 2002, states that the mass-loading approach is preferred 

over the resuspension model for times long after deposition, but that actual air concentration 

measurements are always preferred (Anspaugh et al. 2002, pg. 676). Also Anspaugh 2002 does 

not contain a good definition of near-field resuspension. Hence, reliance on this reference for 

resuspension factors at times long after the initial deposition did not seem appropriate. The 

mass-loading approach gives a different set of numbers. 

In regard to the intake estimates derived from resuspension being larger than air concentration 

measurements, SC&A raised the question of how valid such area air concentration measurements 

were for estimating individual resuspension dose, especially since a Los Alamos study had area 

monitoring known to underestimate 5 to 10 micron particle resuspension. Since these particles 

would dominate the radioactivity content, the use of air concentration measurements as a 

comparison point seemed to be questionable. 

NIOSH and contractor personnel on the call were not familiar with the study. SC&A said it 

would provide the reference. It is: 
Effective Date: 

December 13, 2005 

Revision No. 

0 

Document No. 

SCA-TR-TASK1-0006 

Page No. 

114 of 158 

John Rodgers, Piotr Wasiolek, Jeff Whicker, Craig Eberhart, Keith Saxton, David Chandler, 

Performance Evaluation of LANL Environmental Radiological Air Monitoring Inlets At High 

Wind Velocities Associated with Resuspension, LA-UR-00-3091, 2000. 

It is downloadable from the web at 

http://www.airquality.lanl.gov/pdf/AQReports/LA-UR-00-3091.pdf 

SC&A questioned the TBD assumption that it was “reasonable and probably claimant-favorable 

to assign maximum annual environmental doses for the years 1963 through 1966 equal to the 

maximum value reported for 1967 (i.e., 318 mrem yr-1).” This was because there were airborne 

releases in the earlier period, but no inadvertent airborne releases in 1967. Also since the TBD 

assumed that resuspension decreased significantly after the first 100 days, this back-extrapolation 

raised issues about using 1967 data for the 1963–1966 period. 

NIOSH stated that it had not come up with a better method for this than back-extrapolation. 

With regard to venting — once the venting was identified, they tried to keep people out of the 

downwind plume. 

SC&A said that the question did not refer to a plume due to venting, but to dose from deposition 

many weeks or longer after the test. Further the 318 mrem was an area monitor and not a 

personnel dose measurement. SC&A also asked whether the external area radiation 

measurements indicated a decrease proportional to t-1.2 [where t is time after the test]. 

NIOSH pointed out that 318 mrem per year was the highest ambient dose rate anywhere on NTS. 

From 1966 onward, the numbers were very stable. The idea was to use the 318 mrem per year 

after atmospheric testing had stopped, and the dose contribution was limited to ventings. 

External Dose – Photon and Beta Components 

There was a discussion of correction factors for external dose in light of the NIOSH correction 

factors estimated for Mallinckrodt. SC&A noted that the correction factor in regard to the 

relative location of the organ compared to the badge would not be as large for NTS as with the 

point-source (or close to point-source) geometry that was typical of Mallinckrodt, since NTS 

would be more akin to an infinite plane geometry. While the effect would not be more subtle at 

NTS, it needed to be estimated. Further, the angular dependence issue was important, and 

possibly, far more important at NTS, and the beta component issue may also be different. 

SC&A noted that TLDs and film are calibrated with normal incidence geometry. Angles 

different from normal will introduce an uncertainty into dose measurement, and would result in 

underestimates of dose. The degree of underestimation will depend on angular dependence of 

the film or the TLD, which would have to be calculated using a Monte Carlo or some other 

approach. For instance, exposure would be isotropic when people went into tunnels. SC&A has 

not estimated how big a difference this factor would make for NTS. SC&A also noted that a 

related aspect of the problem was the dose conversion factor issue for external dose that it has 

identified as a separate issue. 
Effective Date: 

December 13, 2005 

Revision No. 

0 

Document No. 

SCA-TR-TASK1-0006 

Page No. 

115 of 158 

NIOSH contractors stated that they would defer to NIOSH and get more information to SC&A 

after the call. This would be on the agenda for the planned October 6, 2005, meeting. 

SC&A noted that this issue has been unresolved for some time. SC&A asked what dose 

reconstructors were doing currently in regard to exposure geometry when it was not AP. What 

are the current instructions about this? Ninety or 95 percent of the information is spread out 

throughout TBD. It would be nice for it to be summarized in a table. For instance, it is not clear 

from TBD whether dose reconstruction should use AP or rotational geometry. If AP is to be 

used, this should be mentioned in the document. 

NIOSH stated that AP geometry is used as a default, along with a default energy range of 30 to 

250 KeV for photons. Hence, DCFs were not currently an issue in the minimum-maximum type 

of dose reconstructions that are currently being done. DCFs that are more than 1 (e.g., bladder) 

are used as they are; those that are less than 1 are rounded up to 1. The DCFs in OCAS guidance 

were designed to be used in best estimates, rather than maximum estimates. Only the lowhanging fruit – minimum and maximum doses – are being done. 

SC&A inquired whether Rev. 01 would contain instructions for converting dosimetry data into 

inputs for IREP that other TBDs have, but which is not now in Rev. 00 of the NTS TBD. 

NIOSH responded that that information would be provided by dose reconstruction supervisors 

and that the TBD was not there to provide all details. 

SC&A pointed out that the detail in question was essential, since its absence could result in 

inconsistent dose reconstruction. Without a uniform guidance on the topic, different dose 

reconstructors would come up with different numbers. 

NIOSH responded that the instruction is provided, but not in the TBD. SC&A inquired whether 

there was a Workbook on the topic. NIOSH responded that that was a whole different side of the 

picture apart from the TBD. 

SC&A noted that it was working with the Advisory Board in order to develop a comprehensive 

review process that included the workbooks. But in the present context, the important question 

was: Is NIOSH saying that the TBD does not provide instructions for dose reconstruction. 

NIOSH responded by stating: “That is correct.” 

SC&A noted that the TBD has included a number of claimant-favorable assumptions on external 

dose, but inquired about extremity dose monitoring and data since this was not discussed in the 

TBD. 

NIOSH responded that it had not come across any cases for bomb assembly workers for whom 

this topic was most relevant. This may be information that was classified. At present NIOSH 

has not looked into it. 

SC&A inquired whether bomb assembly was pending as a part of the TBD, in a manner similar 

to atmospheric testing. NIOSH responded that it was not pending. SC&A then asked how 
Effective Date: 

December 13, 2005 

Revision No. 

0 

Document No. 

SCA-TR-TASK1-0006 

Page No. 

116 of 158 

extremity doses for bomb assembly were being handled. NIOSH responded that Dick Griffith 

would get back to SC&A about that. 

Referring to Table 6.3 on page 25, Vol. 6 of the TBD, SC&A asked whether the conversion 

factor, millirem per mR [there is a typo in the table, it should be millirem per mR, not millirem 

per R] that starts out at 0.45 is for 30 KeV photons. Another question about this table was 

whether these values were for backscatter. NIOSH responded that this question should go to 

Dick Griffith. 

In regard to the dosimeter specifications in Table 6.1 of the TBD, SC&A noted that sometimes 

the high and low sensitive emulsions seem to leave a gap in the middle. One dosimeter read up 

to 5 R and the other started at 10R. What about the problems in the gap between the two 

emulsions, for instance, in case of the DuPont 556 package? SC&A inquired whether NIOSH 

would assume 10 R exposure if there was a reading of 5 R. 

NIOSH responded that it would not affect significant number of people, since not many got over 

5 R per dose period. 

As regards beta dose, SC&A stated that the open window dose was not recorded before 1966. 

Therefore, the issue of beta dose before that time appears to be unresolved. How was skin dose 

being defined prior to 1966? NIOSH stated that it was aware of the issue. NIOSH had come up 

with a solution for estimating that component of the dose for that period prior to 1966 and it 

would appear as an attachment to Rev. 01 of the TBD. 

SC&A raised the appropriateness of using PIC data for dose reconstruction. It was certainly 

inappropriate for beta doses and PIC would not pick up low energy gamma (less than 30 KeV 

photons. 

NIOSH states that it did not believe that PIC data are being used for NTS dose reconstruction at 

present. The use of PIC data may be considered for the time before universal badging if NIOSH 

finds any PIC results in the records provided. In most cases with the re-entry records, the 

estimated doses are contained in the dose record for the year. There may be some variation, but 

so far the two records have been consistent. 

SC&A stated that it was not aware of any way to make PIC readings claimant favorable. NIOSH 

stated that PIC data would only be used if no dosimeter data were available. 

In response to an SC&A comment that there was a wide range of information in the TBD that 

seemed hard to sift for use in dose reconstruction, NIOSH responded that there is an “approach 

document” in the dose reconstruction part of the program that specified how dose reconstruction 

was to be done for NTS. The details on this were provided in the written responses to SC&A, 

under comment 34. [See Attachment 2, Comment 34 and response to Comment 34.] The 

informal approach document is currently under development by Task 5 and is being reviewed 

internally. 
Effective Date: 

December 13, 2005 

Revision No. 

0 

Document No. 

SCA-TR-TASK1-0006 

Page No. 

117 of 158 

NIOSH stated that the approach has been very claimant favorable for use for compensable 

minimum dose estimation. 

SC&A stated that its concern was not so much about minimum and maximum dose estimates, 

because procedures appeared to be robust for them, but about best estimate doses. 

NIOSH responded that some of the guidance documents specify for which category of dose the 

particular approach was to be used. For maximum dose, a generic approach is often used, based 

on a Technical Information Bulletin. If there is something particular to the site that is not in the 

OTIB or TIB and needs to be, it will be put there. The sign off procedure for OTIBs and TIBs, 

generally, is Dick Toohey and then Jim Neton. 

SC&A stated that putting new information generated from maximum dose reconstruction at 

specific sites into OTIB or TIBs sounded like a good idea. But some things like neutron-tophoton ratios may be location specific and difficult to put into an OTIB or TIB. NIOSH agreed 

that this was a valid point and noted that Dick Griffith [not on the call] could elaborate on this 

more. 

SC&A stated that it was a general concern that there was not a good roadmap for dose 

reconstruction. Dose reconstructors need a document that helps them develop a dose and put it 

in the individual’s record. NIOSH agreed and stated that the “road map” for dose reconstruction 

will be contained in the approach document, which will be updated as necessary when guidance 

needs to be revised. 

Neutron Doses 

SC&A had several questions about the basis for neutron dose conclusions. Section 6.3.2.2 and 

subsections contain statements that in other than neutron generator areas, “[n]eutron doses, for 

the most part, were low” (TBD Vol. 6, pg. 28). The TBD also states that neutron doses for 

unmonitored workers can be ignored because exposures were “unlikely” (TBD Vol. 6, pg. 28). 

There is little or no documentation cited as the technical basis for these judgments. Would 

NIOSH provide the references that are the basis for these conclusions? Has NIOSH interviewed 

site experts and workers in this regard? After the conference call NIOSH clarified the position as 

follows: 

Current wording developed for the NTS report in this regard is as follows: 

There was a thermal neutron component in the NTS film badge packet from 1966 

through 1986 to record neutron dose. Since as every film badge packet issued on 

site had this component regardless of potential for exposure, monitoring data is 

not necessarily an indicator of exposure to thermal neutrons during routine 

activities. Most of the neutron exposure at NTS in this time frame occurred in 

Area 25 (test reactor area or NRDS). Low level exposure to neutrons in Area 12 

would only intermittently have occurred and only involved workers who directly 

handled the fissile materials used for testing. During this activity, fast neutron 

monitoring was conducted using NTA film and thermal neutrons were monitored 
 

Effective Date: 

December 13, 2005 

Revision No. 

0 

Document No. 

SCA-TR-TASK1-0006 

Page No. 

118 of 158 

using the standard NTS film badge. Since Mr. <XXX>’s responsibilities involved 

<laying conduit in preparation for the tests and subsequent recovery of 

equipment> and <he/she> was not monitored for fast neutrons, it is unlikely that 

<he/she> was involved in the placement of the fissile materials; therefore, 

neutron exposures were not considered for this dose reconstruction.4 

This is used in the report unless the EE worked at NRDS or one of the other areas 

listed in Table 6-7. 

SC&A noted that the analysis of neutron doses needed to be enlarged. Pantex data for weapon 

assembly are okay, but what about other neutrons doses? The TBD states that the neutron dose 

during atmospheric tests was not significant. But the problem of blast and distance in relation to 

neutron dose needed to be specifically analyzed and elaborated upon. Currently there is no 

analysis in the TBD for the conclusion regarding insignificant neutron doses for personnel during 

atmospheric testing. If some personnel wore dosimeters, the results would be useful. [Post 

conference call clarification from NIOSH: “To date, we have no evidence that neutron dosimeter 

measurements were performed during atmospheric testing.”] 

NIOSH stated that this was a good point and that the problem of neutron doses should be 

analyzed in more detail. NIOSH has seen cases of laborers monitored for neutron doses but that 

was from the late-sixties onwards. Currently this is an outstanding question. However, a generic 

claimant-favorable approach could be developed for use in individual dose reconstruction. 

The issue of neutron doses 1963 and 1966 has been set aside. The people involved would need 

to be identified. The people working on the reactors with neutron exposure potential would have 

been badged from the late 1970s, so Table 6.1 could be used. Records exist for neutron 

measurements in the late seventies and Table 6.1 is applicable for this time period. 

NIOSH has looked at the possibility of alpha –n reactions in the atmosphere. The estimated dose 

resulting from such reactions is less than 1 mrem per year; so it can be disregarded. 

Unmonitored Employees 

SC&A asked for the basis of NIOSH’s conclusion that “unmonitored employees would not be 

likely to be exposed to freshly deposited radionuclides.” NIOSH responded that there was a lot 

of effort into controlling entry into areas around ground zero. They had checkpoints and posting. 

Laborers entering controlled areas would be badged as well. This was not well established 

before 1956. If there were a case of a laborer who said in an interview that he went into a 

controlled area but there was no corresponding film badge data, then a co-worker dose would be 

assigned if and when co-worker data is made available. 

SC&A asked how NIOSH was assigning co-worker doses at present. Was cohort badging part of 

the records? Is there a co-worker study for NTS? 

4

 NIOSH explained that the phrases in triangular brackets would typically have to change to fit a specific 

case. 
Effective Date: 

December 13, 2005 

Revision No. 

0 

Document No. 

SCA-TR-TASK1-0006 

Page No. 

119 of 158 

NIOSH responded that it had not come across records of cohort badging so far. There is 

guidance for co-worker doses for other sites in Technical Information Bulletins 20, 21, 29, and 

31. Those are the co-worker studies that have been finished. They are on internal web site 

[“O” drive]. There is no co-worker study for NTS at this time; such a study may not even 

currently be in the timetable. 

SC&A noted that the posting limit of 10 mR per hour at a checkpoint could still result in dose 

rates of between 1 and 10 mR per hour. This would mean doses on the order of 1 rem per year, 

so that the problem of missed dose for unmonitored workers could be important. The dose rates 

at places like the guard shacks might therefore be significant. 

NIOSH responded that this could be important and that people may have been exposed to 

between 1 and 10 mR per hour. The dose rates were measured in order to put down markers. 

However, the rates shown on the isopleths are not chronic dose rates. They drop off rapidly with 

time and became insignificant. 

Tritium 

SC&A asked whether NIOSH had reviewed the accuracy of HTO sampling using silica gel at 

low humidity levels at NTS. This had been experienced as a problem at Los Alamos. The 

problem at NTS might be greater due to drier climate. NIOSH has not reviewed this issue. 

In response to an SC&A question about high tritium doses in certain periods in tunnels, like 

Tunnels E and B, NIOSH stated it was not currently aware of any E-Tunnel tritium exposure, but 

that it would ask Martha DeMarre about such an exposure. The E-Tunnel exposures in the 

Rev. 00 NTS TBD are 239Pu in 1994. NIOSH has information on the Tunnel B tritium exposure 

incident in Section 5D4.2 of the TBD and also a list of incidents in Table 5D-20 of the TBD. 

The dose data exist for this incident. There is a communication about this incident. SC&A 

requested a copy and NIOSH said that it would be provided. There are no claims for this as yet. 

NIOSH stated that it was aware that B- and E-Tunnel exposures were high but that it has not yet 

seen any claims. The list of significant events provides one guidepost. There is some response 

in regard to the E-Tunnel in the written responses to the questions [Comment 29]. A lot of the 

issues relating to incidents in 1963–1966 period have been set aside. This is a small pool of 

claimants. It would be someone that you can identify as being directly involved in the events. 

B-Tunnel exposures were in 1961 (tritium) and 1963 (iodines). E-Tunnel 239Pu exposures were 

in 1994. Prior to 1961, that was the atmospheric testing period. 

Iodine 

SC&A inquired about isotopes of iodine other than 131I. NIOSH responded that there are 

adjustments for that in Volume 5 of the TBD and that there will be more analysis of this issue in 

Rev. 01 of the TBD. 
Effective Date: 

December 13, 2005 

Revision No. 

0 

Document No. 

SCA-TR-TASK1-0006 

Page No. 

120 of 158 

Ingestion 

SC&A asked about the process of estimating ingestion doses. 

NIOSH responded that people did eat on site (“they did not go back to Mercury for lunch”), but 

that it had not asked whether people ate outdoors. There was a lunchroom underground. NIOSH 

has estimated intakes by assuming a 50 mg soil intake from the most contaminated location. The 

estimated dose is less than 1 mrem per year, so it does not seem to be a significant issue. 

SC&A noted that the NCRP 129 suggested maximum intake value was 100 mg per day. SC&A 

asked whether it was reasonable to use the average concentration of radionuclides in soil in the 

top 10 cm for fresh fallout. Another SC&A suggestion was that NIOSH should do a scoping 

calculation for ingestion dose for the GI tract. NIOSH stated that it would look into the issue. 
 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Effective Date: 

December 13, 2005 

Revision No. 

0 

Document No. 

SCA-TR-TASK1-0006 

Page No. 

121 of 158 

Annex A to Attachment 3: List of NIOSH Contacts with NTS Personnel 

Week of 

Number of 

Contacts/Requests 

with DOE POCs 

or Site Technical 

Staff 

Details 

6/13/2003 N/A • TBD Team assembled 

6/20/2003 0 

7/3/2003 0 

9/12/2003 2 

• Team meeting in Las Vegas 

• Met with Martha DeMarre and Tom Hayes (REECo RadSafe circa 1960– 

1980) on 9/9/03 in Las Vegas 

9/19/2003 4 • Completed successful team meeting and site visit to NTS 

10/2/2003 3 • Contacted Martha DeMarre (3 times) and obtained more documentation on 

incidents 

2/27/2004 1 • Contacted Jay Brady (details in separate e-mail) 

4/16/2004 4 • Contacted Jay Brady (4/15/04 via fax) 

4/23/2004 2 

4/29/2004 1 

5/7/2004 0 

5/14/2004 0 

5/21/2004 0 

5/28/2004 0 

6/4/2004 0 

6/11/2004 0 • Contacted Al Ogurek [Bechtel Nevada Health Physics Manager in the late 

1990s to 2004] on 6/11/04 regarding internal dosimetry 

6/18/2004 0 

6/25/2004 0 

7/2/2004 2 

7/9/2004 2 

7/16/2004 3 

7/22/2004 5 • Completed data capture TBD team trip to Las Vegas 

7/30/2004 0 

8/6/2004 0 • Contacted Jay Brady on 8/4/04 (details in separate e-mail) 

8/13/2004 0 

8/20/2004 0 

8/27/2004 0 

9/3/2004 0 

9/10/2004 0 

9/17/2004 0 

9/24/2004 0 

10/1/2004 0 

10/8/2004 2 

• Contacted Martha DeMarre to clarify NTS Dosimetry records for LLNL 

employees 

• Contacted Martha DeMarre to determine if NTS has specific information on 

bioassay collection days per Ed Scalsky/Liz Brackett’s request 
 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Effective Date: 

December 13, 2005 

Revision No. 

0 

Document No. 

SCA-TR-TASK1-0006 

Page No. 

122 of 158 

Annex A to Attachment 3: List of NIOSH Contacts with NTS Personnel 

Week of 

Number of 

Contacts/Requests 

with DOE POCs 

or Site Technical 

Staff 

Details 

10/15/2004 0 

10/22/2004 1 • Contacted Martha DeMarre to clarify a film badge dosimetry discrepancy and 

request documents 

10/29/2004 10 • Continued to work with Martha DeMarre to clarify film badge dosimetry 

discrepancies 

11/5/2004 8 • Continued to work with Martha DeMarre to resolve NTS data questions 

11/12/2004 5 • Contacted Martha DeMarre to resolve NTS data questions 

11/19/2004 8 

• Travelled to LLNL to obtain references and for discussions with Ike Eichhorn 

regarding NTS dosimetry practices and PLUTO operations, and Charles Meier 

regarding PLUTO operations 

• Contacted Martha DeMarre to resolve NTS data questions 

11/26/2004 3 • Contacted Martha DeMarre to resolve NTS data questions 

12/3/2004 3 

12/10/2004 3 

12/17/2004 3 

12/24/2004 3 

12/31/2004 3 

1/7/2005 8 • Contacted Martha DeMarre at NTS on PLUTO Test run dates 

1/14/2005 5 

1/21/2005 7 

• Visited LLNL discussed NRDS activities (PLUTO, etc.) with Chuck Meier 

and Jim Hadley who were formerly active in the PLUTO program 

• Contacted Martha DeMarre on dates and areas where at NTS test we 

conducted 

• Contacted Michael Terrance Moran retired LLNL on postshot drilling and 

cable gas blocking 

• Contacted Roger Staley on gas blocking 

1/27/2005 2 Contacted Martha DeMarre at NTS on PLUTO Test run dates 

2/4/2005 5 

2/11/2005 5 

2/18/2005 8 

2/25/2005 7 • Contacted Cathy Teasdale (formerly with REECo, NTS) at LLNL regarding 

the NTS Whole-Body Counter 

3/4/2005 5 

3/11/2005 5 

• Traveled to LLNL for discussions with Ike Eichorn regarding the Drillback 

and the Nuclear Rocket drafts and to meet with Gary Mansfield regarding 

uranium isotopic ratio questions 

• Contacted Cliff Penwell regarding ROVER/PLUTO 

3/18/2005 8 
 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Effective Date: 

December 13, 2005 

Revision No. 

0 

Document No. 

SCA-TR-TASK1-0006 

Page No. 

123 of 158 

Annex A to Attachment 3: List of NIOSH Contacts with NTS Personnel 

Week of 

Number of 

Contacts/Requests 

with DOE POCs 

or Site Technical 

Staff 

Details 

3/25/2005 3 

• Contacted Roger Staley LRL/LLL/LLNL & DOE retiree and Michael T. 

Moran LRL/LLL/LANL retired in 1993 to discuss Postshot Drilling for LLL 

and LASL plus other operational activities (crater re-entry and specific events 

related to neutron and gamma exposures 

4/1/2005 4 • Contacted Joanne Norton, NVOO regarding exposures from TRU waste, Area 

5. 

4/8/2005 3 

4/15/2005 3 • Contacted Ike Eichkorn at LLNL for NRDS information 

4/22/2005 5 

4/29/2005 0 

5/6/2005 0 

5/13/2005 2 • Contacted Clifford Penwell NTS REECo retired on Area 401 (NRDS) Rad 

Safe activities 

5/20/2005 4 

5/27/2005 2 • Contacted Bernie Ubank NTS REECo retired on Area 401 Rad Safe activities 

and verified that the Hotbox experiment was carried out in Area 401 

6/3/2005 4 

6/10/2005 2 

6/17/2005 0 

6/24/2005 0 

7/1/2005 3 • Contacted Larry L. White LRL September 1961 to 1966 Retired, Harry L. 

Krikham REECo Retired, and Earl C. (Bud) Forry, REECo retired 

7/8/2005 0 

7/15/2005 0 

7/22/2005 0 

7/29/2005 0 

8/5/2005 0 

8/12/2005 0 

8/19/2005 0 

8/26/2005 0 

9/2/2005 0 

9/9/2005 0 

9/16/2005 0 

TOTAL 181 
Effective Date: 

December 13, 2005 

Revision No. 

0 

Document No. 

SCA-TR-TASK1-0006 

Page No. 

124 of 158 

Annex B to Attachment 3: Summary of NIOSH Contact with William J. Brady 

Resolution of Question Regarding Quantities Used for Reporting the Measurement of 

Personal Exposures to Photons at the NTS, 1962 to 1987 

Richard V. Griffith 

Consultant 

756 Cypress Run 

Woodbridge, CA 95258 

August 4, 2004 

There had been confusion about the quantities that was used to report personal photon 

exposures for the period up to 1987 when the personal dose equivalent was formally introduced 

at the NTS. The individual monitoring calibration information indicated that calibrations had 

carried out in terms of exposure with units of roentgens. However, the records were presented in 

units of rem (Personal dose equivalent implied). 

To clarify this question, on 15 April I sent a Fax to J.W. Brady who had been in charge of 

dosimetry activities at the NTS since the early 1950s, and had served on the National Research 

Council committee that had reviewed film dosimetry at the NTS and the Veterans dose 

reconstruction efforts. In a subsequent telephone conversion, he told me that during this period, 

exposure and dose equivalent for photons had been considered equivalent since the quality factor 

for photons was one. To paraphrase, “An R is a Rad is a Rem.” Therefore, exposure is used in 

this TBD up to 1987. 
Effective Date: 

December 13, 2005 

Revision No. 

0 

Document No. 

SCA-TR-TASK1-0006 

Page No. 

125 of 158 

ATTACHMENT 4: MASTER SUMMARY OF SITE EXPERT 

INTERVIEWS 

Interviews were conducted with 15 former and current Nevada Test Site (NTS) production, 

laboratory support, environmental monitoring, medical, and health physics personnel. Personnel 

represent experience at the test site ranging from 1961 to the present. The interviews were 

conducted by Tom Bell and Kathryn Robertson-DeMers during the course of the NTS site profile 

review. The purpose of these interviews was to receive first-hand accounts of past radiological 

control and personnel monitoring practices at NTS and to better understand how operations were 

conducted. Interviewees were selected based upon their historical knowledge of both 

underground and atmospheric tests, as well as their knowledge of the relationship between NTS 

and the laboratories. Workers were briefed on the purpose of the interviews, and background on 

the Energy Employees Occupational Illness Compensation Program Act (EEOICPA) dose 

reconstruction program and site profiles, and asked to provide their names in case there were 

follow-up questions. Interviewees were offered the opportunity to comment on their particular 

interview summary to verify S. Cohen and Associates (SC&A) had accurately captured what was 

said. 

The information the workers provided to SC&A has been invaluable in providing us with a 

working knowledge of the radiation protection program, atmospheric testing, underground 

testing, tunnel re-entry, and safety tests. Below is a summary of worker input. This information 

provided is not a verbatim discussion but is a summary of information from several interviews. 

Individuals have provided this information based on their personal experience. 

General 

There were several agencies involved in testing at NTS, including the Defense Nuclear Agency 

(DNA), Lawrence Livermore National Laboratory (LLNL), Los Alamos National Laboratory 

(LANL), Sandia National Laboratory (SNL), Reynolds Electrical Engineering Company 

(REECo) the site contractor, and other supporting subcontractors. The weapons were primarily 

designed and provided by LLNL and LANL. REECo was responsible for drilling the holes and 

digging tunnels. They employed miners and drillers to perform these operations. EG&G was 

responsible for fabricating the diagnostic equipment used in testing. This equipment was placed 

in massive canisters. The weapons were shipped to the test site by the laboratories, along with 

engineers and scientists who later evaluated the results of the testing. Experimental physicists 

were responsible for evaluating the technical aspects of the event. If in fact, LLNL had a jet 

called “Amy” which was used to transport laboratory personnel back and forth to the test site. 

Laboratory personnel could be stationed at the test site for weeks, depending on the particular 

test. 

Atmospheric Testing 

A majority of the United States nuclear testing occurred at the NTS. During the late 1950s and 

early 1960s over 100 atmospheric tests were detonated for which there was no containment 

effort. These tests were conducted at Frenchman Flats and Yucca Flats. NTS areas associated 

with atmospheric testing included Areas 2, 3, 4, 5, 7, 9, and 10. Tests focused on evaluating new 
Effective Date: 

December 13, 2005 

Revision No. 

0 

Document No. 

SCA-TR-TASK1-0006 

Page No. 

126 of 158 

weapons designs. Detonation occurred by various methods, including use of numerous towers 

built for the atmospheric tests in the 1950s and early 1960s. The Nuclear Test Ban Treaty ended 

atmospheric testing at NTS in 1962. 

Laboratory Testing 

The device was constructed as a design model at the laboratories. Some of the final assembly 

work had to be coordinated with other laboratories. At times, parts would be transported to 

Nevada and assembly of the device would be completed. The design of the diagnostics canister 

was done by the responsible national laboratory and it was assembled at the site by contractors 

such as EG&G in Las Vegas. Some of the canisters were built at the EG&G facility and 

transported out to the test site. 

To install the canister, a circular hole was drilled into the ground. The canister was lowered into 

the hole. Different layers of backfill (different materials) were added. Attached to the canisters 

were the diagnostic cables used to record performance of the device. These diagnostic cables 

came up through the ground and went to trailers, which were at an adequate distance from the 

ground zero. Recording was conducted without the presence of employees in the trailers. When 

the subsidence crater occurred, the cables could be pulled away from the trailers. 

The shots were fired from a Control Point (CP) where test support staff was located. The CP 

overlooks the Yucca Flats where the tests were done. All of the pre-shot evaluations were done 

there. Containment physicists reviewed the design of the containment with the Site Director. 

There were early morning briefings on the weather conditions to discuss the stability of the 

weather. The shot were not performed during bad weather. The Site Manager gave the okay. 

The device was then detonated. The diagnostics were collected and recorded during the shot by 

the remote equipment. 

Typically personnel gained access to the area. Post-detonation, the health physics personnel 

entered the area to determine whether radiation leakage had occurred. When the all clear was 

given, scientists went into the area to retrieve the information recorded by the remote system in 

the trailer. 

There was a radionuclide characterization of the gas. At one end of the pipe was a nuclear 

device, and 400 feet away there were optical diagnostics to observe the prompt radiation in the 

pipe. In between, there were four alcoves with diagnostics to track the progress of the shot. 

Slifers were placed in the wall to monitor the propagation of the shot. They compared the 

experimental data with the calculation theory. They were looking for good agreement. During 

the “Marvel” event, they tried to collect gas samples that made it to the end of the pipe. After the 

event, the collection system was pulled up. They wanted to know whether the radiation debris 

came from the device itself. 
 

Effective Date: 

December 13, 2005 

Revision No. 

0 

Document No. 

SCA-TR-TASK1-0006 

Page No. 

127 of 158 

Defense Nuclear Agency Testing 

The DNA conducted tests with weapons of known design. Underground testing was primarily 

conducted at Rainer Mesa (i.e., Area 12 and Area 16). They were used by DNA for tunnel and 

transient radiation effects research. 

Tunnels were dug into portions of Rainer Mesa facing Yucca Flats to support DNA operations. 

The weapon was placed at one end of the tunnel and the rest of the tunnel was used to place open 

pipes for transient radiation effects studies. It is important to note that different tests may have 

been performed in the same general areas. The bomb was detonated. As gases from the 

explosion cooled, the overburden collapsed above the nuclear device. The ground had to be 

stable prior to re-entry, and the area had to be cleared for health purposes. 

Tunnel Re-entry 

Tunnel re-entries were done to evaluate the infrastructure and help to decide whether it was safe 

to go back in or not. The tunnels were well constructed and had containment doors which sealed 

and prevented gas and debris from getting into the tunnel. In almost all cases, these containment 

doors worked well. If there were leaks, these usually occurred from leaks through fissures and 

cracks in the surrounding rock, backfill, or drillbacks. During one of the first tunnel tests the 

containment systems failed, and there was a fireball that came out of the mouth of the tunnel and 

vented into Area 12. 

Radiation from gas sampling and debris was analyzed with a gas chromatograph and with 

gamma monitors to determine when it was safe to go back in. This was usually within one or 

two days, but sometimes sooner. If all seals held, they were able to go back in quickly. These 

re-entries posed the greatest potential for internal and external exposure at the site. Entry into 

tunnels had to be preplanned in order to reduce exposures. A few months after tunnel tests, 

radiation levels still were around 1 R/hr. To help to reduce personnel dose potential to radiation 

and chemicals, health physics (HP) and industrial hygiene (IH) personnel employed use of 

multiple crews and time limitations. The establishment of multiple crews meant that each crew 

only worked in the tunnels every other week. HP and IH entered the tunnels initially to 

characterize the exposure conditions. There were detectors on the wall to assist in monitoring 

levels of radiation. If individuals approached the Administrative Control Limit (ACL), they 

were told to discontinue work and exit the area. 

Radiation safety re-entry personnel went into the tunnels wearing anti-contamination clothing 

(Anti-Cs) and full-face respirators. Initial teams went into tunnels with Scott air packs. HP and 

IH considerations were determined simultaneously. 

There were some tritium exposures documented in the tunnels. The tunnels at NTS became 

closed atmospheres only when the air exhaust system was turned off and the portal was sealed. 

Otherwise, tunnels had air exchanges via the drawing of air from the area of the drift face, and 

they routinely experienced a phenomenon called “pumping” as temperatures changed over a 

24-hour period. Where there was water in the tunnels, tritium was sometimes detected. For 
Effective Date: 

December 13, 2005 

Revision No. 

0 

Document No. 

SCA-TR-TASK1-0006 

Page No. 

128 of 158 

example, B-Tunnel had tritium-contaminated water. When tritium was detected, they may have 

sealed off the tunnel and not used it for future tests, depending on the amount of tritium detected. 

In regards to internal dose, underground test safety test personnel did wear respirators upon reentry. Los Alamos National Laboratory was concerned about the dust levels and the potential for 

inhalation. LANL did a study, took nose swabs, and wrote a report on the condition hazards. 

They also did an analysis of the decontamination process. 

Under the current management of operations, workers wore double Anti-C clothing, a full 

respirator, and a personal air sampler known as the “giraffe sampler.” In the past for the same 

situation, personnel wore booties, coveralls, and gloves because nothing was moving or being 

resuspended. 

High-Yield Nuclear Test 

The Jorum Event in 1969 was a high yield test that was felt miles away in Las Vegas. To 

prepare for the test, a 12-foot diameter hole was drilled into the ground. The initial placement 

design was at 3,400 feet. Since this area was previously used as a well, the test placement was 

moved to approximately 4,000 feet underground into the ground below a water well. The area 

around ground zero was vaporized and melted rock was found at farther distances away. For 

example, a one megaton shot vaporized rock up to 20 meters in radius and melted rock as far 

away as 40 meters in radius. 

Dynamic Studies of Gas Flow 

The dynamic gas flow studies were conducted over a wide range of exotic high-energy pipe 

flows. For example, Project Plowshare’s Mock 500 piping (“Marvel” event) was used close to 

the nuclear event. The exposure potential resulted from the exposure in the area due to previous 

tests that had been done. 

Spent Fuel Climax Project 

Tunnels used for the Spent Fuel Climax Project (SFCP) were left over from the “Piledriver” 

experiment. During this project, they excavated a large area of tunnels in the granite rock. 

Tunnels that went back to the area where the explosives were set off were closed up. The 

elevator was located at the top of the surface where the excavated material was hauled out. They 

added a large room, which was used as an assembly area. The elevator was used to carry 

materials down to this room. This room should not have been affected by the explosions. For 

the SFCP, gauges and other equipment had to be installed in the wall that was near the spent fuel 

sites. Spent fuel rods from a reactor were loaded into storage areas underground in the room. 

Placed in the rock in the immediate area were the diagnostics to analyze the effects on the 

granite. Operations were done remotely. A report was issued on the setup of the SFCP. This 

work lasted approximately 5–10 years. 
Effective Date: 

December 13, 2005 

Revision No. 

0 

Document No. 

SCA-TR-TASK1-0006 

Page No. 

129 of 158 

Other Projects and Tests 

Area 11 is commonly referred to as Plutonium Valley. Mock-up devices containing weapons 

grade plutonium were tested in this area. As a result of these safety experiments, the plutonium 

did not burn up and was dispersed throughout the area. It is expected that most devices tested at 

the NTS had sufficient plutonium to fission. When dispersed, this plutonium had the potential for 

inhalation doses over relatively large areas. For some events, such as the “Small Boy” site in 

Area 5, the device yield was small enough that there was plutonium dispersed with the fission 

products produced during the detonation. In some areas, safety tests were conducted over the top 

of old atmospheric test areas. This made it difficult to assess the plutonium contamination with 

high exposure rate levels at the same location. 

At “Gnome”, the experiment was to try to use an underground test as a steam generator for 

electricity. Water was pumped into a previous test underground cavity and the water was super 

heated by a nuclear detonation producing steam. 

The “Smoky” event was conducted on August 31, 1957, in Area 8. Three safety tests were 

conducted in the vicinity of the “Smoky” site leading to plutonium dispersal. The highest level 

of 241Am and 239,240Pu identified in soil samples to date were those samples taken after these 

three safety tests. These events were conducted within eight days of one another. The number 

of personnel who may have entered these locations between each event is not known, nor is there 

information on what dosimetry and personal protective equipment (PPE) requirements were in 

place. 

Bechtel Nevada (BN) currently has a contract with other facilities to ship waste to the NTS for 

burial. For a number of years the NTS agreed to receive shipments of legacy waste from these 

facilities. LLNL began storing this legacy waste in the early 1970s. It remained stored at LLNL 

for a number of years before finally being shipped to NTS where it was also in storage for many 

years. NTS waste handlers still find liquid in some of the drums and they have to dewater them. 

NTS waste handlers also found mixed waste, (i.e., beryllium pieces) inside, which caused 

industrial hygiene problems in handling these materials. They found things in the drums that 

surprised them. The objective was to segregate the transuranic waste, repackage all the nontransuranics back into the drums, and then take the drums back for burial in Area 5. When they 

found beryllium, the drums had to be unpacked and re-packaged again, ensuring that the 

beryllium was segregated off by itself. The transuranic waste went to the Waste Isolation Pilot 

Plant (WIPP) for final disposal. They are getting close to finishing the legacy waste from LLNL. 

This should be done by the end of 2005. 

Radiological Control 

Contractor Environmental Safety and Health personnel had minimal presence during the set-up 

of a testing location. Most of their support was provided pre- and post-event. The pre-event 

support consisted of exposure rate surveys of the expected entry route and at the ground zero 

area before the event was conducted. Post-event support consisted of exposure rate surveys after 

the device was detonated and during experiment recovery. This work scope included most 

above-ground and underground events. 
Effective Date: 

December 13, 2005 

Revision No. 

0 

Document No. 

SCA-TR-TASK1-0006 

Page No. 

130 of 158 

There were a variety of radiological hazards associated with weapons testing. During the 

atmospheric testing there was prompt radiation. For underground and atmospheric testing, there 

was radioactive fallout. The fallout was disbursed by the wind. As a result of testing, the entire 

site was/is contaminated to some extent. With the 40–45 years that have passed since 

atmospheric testing, there has been radioactive decay of some radionuclides. Individuals 

working in the earlier years were exposed to more radioactive material than those that are there 

currently. 

The radionuclides of concern were generally mixed fission and activation products such as 60Co,

90Sr/Y, 106Rh-Ru, 131I, 134Cs and 137Cs. There is also 152Eu, 154Eu and 63Ni found onsite or in the 

waste stream. Plutomium-239,240, 238Pu, and 241Am were dispersed when mock-ups of different 

weapon designs were tested to determine the potential of accidental fission from storage or 

transportation accidents. Weapon’s grade plutonium was dispersed over numerous ground zero 

areas of the NTS. There were special events at the test site that involved 233U. Thorium and 

polonium were not an issue during weapons testing and post-detonation operations. The highest 

radon levels were observed in G-Tunnel which was due to the geology and less ventilated areas 

within the tunnel. Yucca Mountain has similar geology to G-Tunnel, and has some posted radon 

areas deep down. Those who read the regulations closely want to approach radon as an 

occupational dose. Strontium-90 and 137Cs are the more prominent radionuclides at NTS. 

Depleted Uranium was used in artillery round experiments done by the Department of Defense 

(DOD). 

Over the history of the NTS, numerous support camps have been established in the forward areas 

in support of the testing programs. These support camps were near above-ground and 

underground ground zeros in many instances. If an event deposited contamination on a camp or 

major roads, decontamination efforts were utilized to quickly reopen access to these roads and 

facilities. Once an area was declared “clean”, eating was allowed in these facilities and on the 

major highway that went through the test site. For most of the forward areas, all personnel wore 

dosimetry and permanent air sampling stations were used to document the success of 

decontamination efforts near active facilities. 

Most of ground zero areas were accessed by road. Many of these roads were used routinely 

between events and after the locations became inactive. Many are still used with the appropriate 

warning signs and fencing is maintained to prevent unplanned access. 

Posting and fencing of residually contaminated areas was initiated in the late 1960s and early 

1970s once the above-ground ground zero areas were on a permanent inactive status. This was 

especially true of plutonium areas. Prior to this, there was no posting or fencing of above-ground 

ground zero areas because they were used numerous times, and the fencing would have been 

destroyed by subsequent events or by post-event clean-ups to prepare the areas for the next 

event. 

Posting and fencing did limit access to areas, but these areas were not policed. Many of the sites 

and their access roads are relatively remote. It was assumed that the training and briefings 

received by personnel who entered the NTS would prevent entries into these areas without 
Effective Date: 

December 13, 2005 

Revision No. 

0 

Document No. 

SCA-TR-TASK1-0006 

Page No. 

131 of 158 

Radiological Control support. Compliance was generally good, but there were numerous 

instances where signs or fences had been knocked down or they were ignored. 

There are numerous radioactive sources onsite for various projects. Some of the sources 

formerly or currently onsite include: 

• 	 Eighty-eight one curie 137Cs sources that were placed around the underground shaft at 

“Sedan” and blown out by the detonation. LLNL found two of these sources in 1989 

performing surveys with gamma spectrometers. 

• 	 LANL receives all orphan sources like AmBe and PuBe that are sent to NTS from other 

DOE facilities for storage and that are eventually sent onto the WIPP. 

• 	 Both Areas 3 and 5 receive some waste from other facilities including sources. For 

example, the University of Hawaii sent an old 1,200 Ci Cs source to the NTS for burial in 

the spring of 2004. They had to get the source into a special shielded container that is 

now buried out in Area 5 in a trench. Area 5 is one area where waste handling people 

either currently or in the past, worked around the glove box operations during waste 

separation. 

• 	 Livermore had a 252Cf source in a water well they used for operations onsite. 

The deployment personnel, which are part of the nuclear emergency search team and the 

personnel working at the remote sensing lab at Nellis Air Force Base (AFB) and Andrews AFB, 

were the groups of people who worked with mobile sources. They use these sources to do 

response checks on their instruments and they get small doses. The dose is small, but they 

routinely get dose because of the small check sources, which are in front of them. 

Los Alamos National Laboratory (LANL) and Lawrence Livermore National Laboratories 

(LLNL) personnel currently work with the orphan source recovery program, and they handle the 

drums coming into the NTS from other DOE facilities and the placement of these drums into the 

storage bunkers in Area 6. The number of neutron sources is increasing in this area. LLNL 

people are getting 30–40 mrem/quarter. The top exposure is 60 mrem/quarter in Area 6. 

With implementation of the Radiological Control Manual, the site went to the use of Radiation 

Work Permits (RWPs). Now all work is laid out in the RWPs. There is less Radiological 

Control Technician (RCT) coverage needed as a result. Up until the implementation of the 

Radiological Control Manual, radiological safety personnel did not use RWPs. With the more 

strict regulatory emphasis, the RWPs made the process better, reduced the dose to personnel, and 

brought better procedures. 

Prior to RWPs, the health physicist had the flexibility to make local decisions. Now operations 

have to follow a prescribed process that may need to be amended but cannot be done so without 

significant effort. Work performed today is based on regulatory requirements rather than 

personal experience. 
Effective Date: 

December 13, 2005 

Revision No. 

0 

Document No. 

SCA-TR-TASK1-0006 

Page No. 

132 of 158 

Samples were taken from the puddle at the bottom of the test cavity at an appropriate time after 

detonation. These samples were like “Trinity” glass. They then punched out some of this core 

material and placed it into a bottle. The potential for dose was in the multiple R range. They 

used tongs to do the job, but sampling personnel still got dose. Chemists liked to play with the 

“Trinity” glass-like material found at the bottom of the cavity, but Radiological Control 

personnel kept their contact time to a minimum, and exposures were kept down in spite of 

potential for high dose. 

Due to the low potential for neutron exposure onsite, there is a limited inventory of neutron 

survey instruments. There are shipments received onsite which require neutron survey. For 

example, when the subcontractors come in with moisture density gauges (Trauxler gauges with 

AmBe sources in them) neutron surveys are performed. Neutron survey instruments are sent off 

periodically for calibration to a vendor that has met the DOE contractor assurance program 

(DOECAP). The vendor is periodically audited. If you have multiple DOE facilities using the 

same kind of neutron monitoring equipment to be calibrated, these multiple DOE facilities join 

together to do one group audit rather than every individual customer auditing Thermos’ neutron 

calibration process. Neutron surveys are completed in areas were neutrons are expected to be an 

issue. 

Internal doses were a problem in 1967 at the Henre Facility (High Energy Neutron Reactor 

Experiment) facility. It was necessary to change out the target for the accelerator which had a 

2000 Ci 3

H source. During this change out, a degassing process happened. Personnel went into 

the area in bubble suits, but they still got doses in the μCi/cc range. 

Current instrumentation in use at NTS includes Geiger Mueller counters with pancake probes 

and Pocket Ionization Chambers (PICs). During the days when REECo was doing operational 

calibration, the instruments were calibrated according to the specification at that time. Now 

there are calibration procedures that are approved by the Radiological Health instrumentation 

personnel. 

External Monitoring 

External dose was the dose of most importance at NTS. Internal dose was only a fraction of the 

external dose in most situations. In terms of collective rem/year, the NTS was always lower 

than any of the other DOE facilities. The site depended on film badges and later 

thermoluminescent dosimeters (TLDs) to determine external dose. 

Prior to 1956, badges were primarily issued by the First Radiation Safety Support Unit (RSSU) 

operated by the U. S. Army. During the atmospheric nuclear testing era, a film badge was issued 

to any individual or group of military personnel who were to enter a controlled area (known as a 

RADEX area.) REECo took over the Radiation Safety functions at the test site in March of 

1956. Prior to that period of time, people entering a controlled area were issued dosimetry by the 

military. From March 1956 through 1965, a person passing through the checkpoint entering the 

test site was required to wear a separate film badge and a separate security badge, both issued by 

REECo. In 1966, the film badge was combined with the security badge. In more recent times 

this design was replaced by two separate badges that are in use today. From 1957 to 1992, 
Effective Date: 

December 13, 2005 

Revision No. 

0 

Document No. 

SCA-TR-TASK1-0006 

Page No. 

133 of 158 

during the underground testing era, everyone who entered the test site was assigned a badge. 

Security guards ensured that the film badge was issued and they collected the film badge for 

processing. The contractor provided dosimeters to all individuals onsite including Atomic 

Energy Commission (AEC), DOE, LLNL, LANL personnel, and other support organizations or 

visitors to the site. The process of assigning doses to subcontractors and visitors was as thorough 

as badging for regular onsite workers. Visitors, government employees, and subcontractors were 

monitored according to the same criteria as employees. For visiting laboratory personnel, badges 

were maintained at NTS on a badge rack. In almost all cases, anyone coming through the gate 

was badged, including infants brought into Mercury to see a ball game. Therefore, there were 

children and infants monitored. In such cases or if a visitor to the NTS did not have a social 

security number (SSN), you would see a birth date for identification purposes. 

Temporary badges were issued if the person forgot to bring their badge that day. These badges 

were issued with a particular identifier for the individual and the computer would add all badge 

readings together automatically, so all dose was recorded. There were test cases run to ensure 

that such data was not neglected. Therefore, the system would accept as many dosimetry issues 

on the person as actually happened. 

Cohort badging was not a common procedure at NTS after March 1956. Since March 1956, 

NTS personnel were badged with their own badge. Although individual badging was used 

primarily by the military, the military did make more use of cohort badging. There was only one 

exception. Sometimes film badges were not used for certain tour groups where it was planned 

that they would not get off the bus or would not go into a radiological area. In such instances, 

visitors were not all badged but relied on the dosimeter of the tour guide. 

The underground nuclear test era ended in 1992. By late 1992, a new film badge policy was 

being considered and was implemented in 1994. From 1994 and later, it was no longer required 

that non-radiological workers wear film badges. This policy was not readily accepted by LLNL 

and they continued to monitor all their personnel. The statistics of doses at the test site shows 

that 99% of personnel received a zero rem dose. Zero doses for almost all workers at NTS might 

be anticipated since, unlike other DOE facilities, NTS workers were not dealing with hands-on 

processes. Instead, they received acute event exposure, if anything at all. Therefore, there were 

not the usual long-term chronic doses often seen in other DOE facilities. At the test site, there 

was no production of uranium or plutonium. Nothing was being made at the test site. Large 

exposures are the exception at the test site and are very few and far between. Any overexposure 

resulted in a large-scale investigation and a positive dose report, since they were so uncommon. 

Positive dose reports were prepared and distributed on a daily basis. The positive dose report for 

any non-NTS, laboratory, or military person was forwarded either to the military, the 

laboratories, or the individual’s parent agency. 

For visiting laboratory personnel, badges were maintained onsite in a badge rack at NTS. LLNL 

policy was to have their personnel use NTS dosimeters while working on the test site. LLNL 

personnel that came to NTS were instructed not to bring their LLNL badge. NTS made sure the 

local dosimetry results were sent to LLNL including zero readings. 
Effective Date: 

December 13, 2005 

Revision No. 

0 

Document No. 

SCA-TR-TASK1-0006 

Page No. 

134 of 158 

The supervisor was responsible for telling individuals when they were close to the ACL. PICs 

were worn in the controlled areas. If the PIC was positive, the badge was pulled for immediate 

processing. The supervisor had the latest film badge results plus any subsequent PIC results. 

These were added to evaluate whether individuals were within the limit. The dose was zeroed 

out on January 1st of each year. During the period from September to December 1961, some 

miners in the B-Tunnel did approach the administrative limit of 3 rem per quarter. A request was 

made to the AEC asking that such workers be allowed to exceed the three rem per quarter 

administrative limit, allowing them to use their full 5 rem/year allowance in that one quarter. 

AEC made the decision that such workers should not be allowed to exceed the 3 rem/quarter 

limit. 

Bechtel Nevada (BN) has developed a summary analysis of the statistics of badging individuals 

during the period of underground testing that covers the period from 1961 to 1997. These 

statistics document the decline of badging after the moratorium on underground testing became 

effective in 1992. In the 2 or 3 years prior to the end of underground nuclear testing, the Nevada 

Test Site was badging 28,000 to 29,000 people with dosimeters. In 1993, about 26,000 people 

were badged, by 1995 only about 15,000 people were badged and by 1998 it was down to 3,000 

people badged. Since then, the number of people badged has been going back up. It’s hard to 

imagine, with those kinds of quantities being monitored and the fact that the dosimeter was part 

of the security badge assembly, that there would be much of any opportunity for someone to get 

through the entry checkpoints without a dosimeter. 

Beta/Gamma 

In the external dosimetry technical basis document, a description of the program is carried 

forward through the revisions. There is information that can be useful that is in all the different 

revision levels of the technical basis documents. Information goes back to 1951 at the beginning 

of the testing at the NTS. The documents give description of the dosimeters used at various 

times over the years right on up to the present. It has some information of the general useful 

ranges of the dosimeters. It does not talk about how they kept track of dose information in dose 

records; it does talk about the dosimeter itself. The external dosimetry program is accredited on 

a 2-year basis, so the technical basis documents were/are updated at the same time. 

Film badges were usually exchanged on a monthly basis. TLDs were exchanged on a quarterly, 

semi-annual, or annual basis. The dosimeter had filters to distinguish between gamma, x-ray, 

and beta dose as they developed through time. Determination of density of the film badges was 

done by recording several areas on the film badge if it looked like the badge density was not 

uniform. Sometimes it was very evident that there was heat or aging damage. In regard to open 

window exposure, the algorithm backed out any penetrating radiation of low enough energy that 

could be confused with the actual beta exposure. There were also calculations of exposure to the 

lens of the eye. The dosimetry form included a lot of information on types of film, frequency of 

film badge changes, and problems with film in the report. 

Controls and standards were processed with each film batch during processing each day. DuPont 

film was used in film badges and in 1970 they switched to Kodak film. The response of the two 
Effective Date: 

December 13, 2005 

Revision No. 

0 

Document No. 

SCA-TR-TASK1-0006 

Page No. 

135 of 158 

types of film was different. They had to put a binary label on each Kodak film, unlike DuPont 

film which was prenumbered. 

If a zero dose was seen, historically it was recorded as zero. Doses of 30 mrem or greater were 

recorded as the dose of record. There were routinely 15 mrem badges and they would be 

recorded as zero because of the potential error in a true exposure. The minimum detectable dose 

(MDD) for current TLDs is 10 mrem for gamma and 10–15 mrem for beta. 

For the “Buster Jangle” test series, LANL did the dosimetry and recorded the dose. The MDD 

was either 50 or 60 mrem. Dose less than these values was recorded with a code indicating that 

the doses are less than values. 

Once workers were allowed to take their dosimeter home, there was a problem with unreturned 

badges. Workers would simply forget to bring dosimeters back. Badge delinquency was 

significant in laboratory personnel (LLNL and LANL) and contractor personnel. Delinquency 

was fairly high even in the early 1980s, but has improved significantly during the 1990s to the 

present. Fading, heat, and age affected the film badge. People would come in after a 6–8 month 

absence and turn in their badge. They were issued a new badge and the old one was processed. 

These film badges had to be processed separately in order to account for the aging component. 

The older they were, the harder it became to make the needed corrections. If the film in the film 

badge was over 2-years old, they just recorded a dose based on what they had done with other 

coworkers since they couldn’t get any meaningful density reading off the film. This was also a 

problem with TLDs and track-etch dosimeters. 

NTS badges were processed by NTS. At times, laboratory workers turned their laboratory 

dosimeter into NTS. These had to be returned to the appropriate laboratory for processing. 

Although laboratory personnel may have traveled with their laboratory dosimeter, they were not 

allowed to use their laboratory film badge for work onsite at NTS. 

Although all national laboratory personnel were given NTS dosimeters for use in monitoring 

their potential NTS exposures, some are known to have worn their lab dosimeters “to check on 

the NTS dosimeter program.” This practice was discouraged by both their employer and NTS 

personnel, but it is known to have happened on an infrequent basis. Thus, any NTS exposure 

would have also been recorded on their lab dosimeter. 

When dosimeters were lost or damaged, or highly exposed, a dose investigation was completed. 

Damaged film badges were evaluated by reading the film and making a notation of this damage 

on the log sheet. There were some conditions where the badge could not be read. For example, 

some guards’ badges had the plastic in their film badge warped so badly by heat that the film in 

the film badge could not be read. The final dose assignment was based on an interview with the 

person, field data, and coworker data. Because such a small population had a positive exposure 

during the year, normally the readings were zero. If the individual belonged to a group which 

did receive exposure, a more detailed analysis of the job tasks was completed. This made it 

more complicated to reconstruct a dose. If it became too difficult to come up with a hard 

number, a worst case dose was assigned. Estimated doses are flagged in the dosimetry records. 
Effective Date: 

December 13, 2005 

Revision No. 

0 

Document No. 

SCA-TR-TASK1-0006 

Page No. 

136 of 158 

Much of the time, unexpected readings on dosimeters were the result of the dosimeter being 

worn during medical x-rays. The individual having nuclear medicine tests and/or treatments, or 

the dosimeter being run through screening equipment at the airport, are examples of these kinds 

of unexpected readings. One security employee’s film badge is an example of what is known as 

a “suitcase dose.” The x-ray screening of the individual and his personal effects at the NTS 

security gates does not add any dose to their dosimeter. But when individuals leave their 

dosimeter in their luggage at the time of checking in for an aircraft flight, the dosimeter goes 

through a Computed Axial Tomography (CAT) scan and the dosimeter can get a dose of 

300 mrem or more. There is, however, a very significant signature pattern under the four 

elements of the film badges’ filters, so that it is easily recognized. An investigation was 

completed and it was verified that the badge was checked in with luggage at the airport. This 

happened several times a quarter. These occurrences are well documented in the dose record. 

Orientation of Exposure and Multiple Badging 

There were situations where partial body exposure to the skin, gonads, or lens of the eyes 

occurred. Under these conditions, multiple or extremity dosimetry was used. Originally they 

used impregnated Teflon TLD disks. They could not be reused. As a result of this, there was a 

switch to TLD chips for extremity use in 1977. TLDs gave lower detection levels as well as 

being reusable. There were a lot of advantages to making that change. When NTS evaluated the 

brand new Harshaw models, Harshaw let the site take them for several months to do studies. 

This benefited Harshaw, because they wanted field testing data on their system. 

Multiple badges on several areas of the body were sometimes used when non-uniform radiation 

fields were present. These multiple film badge locations were usually obvious. For example, 

multiple dosimeters were to be used while opening drums to remove the waste or during 

different burial purposes. Coveralls were designed to facilitate multiple dosimetry with little 

pockets on the sleeve and thigh where you can insert additional dosimeters and they stay there. 

The site had an established procedure for when extremity and multiple dosimetry was used. The 

official film badge or TLD of record was worn on the chest. They may have had TLDs taped on 

their body to see if there was any difference. More often than not, when an incident occurred 

there was no dose other than the whole body. This kind of data was all put on microfilm that is 

now in the Nuclear Testing Archive (NTA). 

There was a 125 Ci Cs source that NTS was disposing of. It had been stored down in a well and 

they were going to retrieve it from the well and send it off to burial. They did surveys as it was 

brought up. Once it was brought up high enough, they wanted to leak test the source. It was 

maintained in a water-cooled system. Because they were leaning over the well, there was an 

obvious shielding effect and parts of the body would be exposed and parts of the body would not 

be exposed. They used 3 multiple dosimeters on each of the people working on the task. There 

was no meaningful dose. The practices were coordinated well enough that the highest dose was 

about 30 mrem. With doses that small, it is hard to measure the gradients (i.e. how different is it 

on the right arm versus the top of the head versus the chest location etc.) There are not jobs at 

NTS where the dose rates are high enough to get a meaningfully different dose from one part of 

the body to another. In regard to dose on the back of the body versus the front of the body, with 

the work being done out here now, NTS hasn’t encountered that. One of the questions being 
 

Effective Date: 

December 13, 2005 

Revision No. 

0 

Document No. 

SCA-TR-TASK1-0006 

Page No. 

137 of 158 

asked for the homeland security facility that is being designed right now involves the location of 

sources in relation to people working in the facility. It will be important to know what the dose 

will be when a worker is working with one device and another source may be behind him. 

At nuclear power plants, dose rates can be variable and dosimeters are needed to determine doses 

to different parts of the body. At NTS, where the dose at the chest is 20 mrem and the head is 

30 mrem, a difference of 10 mrem does not justify doing all the extra work to quantify the 

difference, as this is within the uncertainty of the film badge reading. 

Neutron 

There are not many areas at NTS where neutron radiation is an issue. Some neutron exposure is 

associated with the reactor at Area 27, also known as Area 410, related to the Nuclear Rocket 

Development Station (NRDS) for tests like “Super Kukla.” Neutron exposure was also a 

possibility from the nuclear propulsion engines in Area 25, also known as Area 400. This 

involved such tests as “Rover”, “Kiwi”, and “Rhoades.” In Area 26, there were tests which 

resulted in some neutron exposure. In regard to neutron dose at the atmospheric tests, the only 

possible source of neutron dose would be from prompt radiation from the nuclear detonation. 

However, personnel were not permitted close enough to receive such neutron exposure. 

The Area 5 waste handling area deals with potential neutron exposure, as does the orphan source 

recovery program at LANL in Area 6. LANL is collecting sources as part of their orphan source 

recovery program. Their mission at NTS with respect to orphan sources concentrates on neutron 

emitting sources. LANL has bunkers full of neutron emitters. 

Neutron Track Type A film was used until the mid-1970s and had been used for almost a quarter 

century. It was realized that the NTA film was not capable of monitoring low energy neutrons, 

and the NTA film was not valid for accurately determining neutron dose. Neutron film was 

reported to have an energy threshold of 600 KeV. The biggest issue with neutrons was getting a 

handle on neutron energy to do an accurate job of estimating neutron dose when it was seen on 

the dosimeter. The minimum detectable dose (MDD) for NTA film was 30 mrem for neutrons. 

With the inadequacies in NTA film, NTS started to consider other options. The only technology 

which made sense was the use of the LiF-6 and LiF-7. In 1978 or 1979, the new TLD Albedo 

dosimeter, which used lithium six and lithium seven chips, was developed. This dosimeter was 

capable of monitoring much lower energies of neutron and was a better dosimeter for recording 

neutron exposure. The MDD for TLDs was from 10 – 15 mrem. 

There were no significant differences in badge response between the calibration source and what 

was actually seen in the field. The calibration process was working and any differences in 

source term were accounted for. During the switch from NTA film to TLDs, the spectrum was 

graphically represented and a calculation of the response was determined to give the true dose. 

The TLDs worked, but the NTA film did not. They did not go back to apply any correction 

factors for the NTA film. When they used NTA film, they never got a positive reading because 

they were never dealing with neutron spectrums of high enough energy to leave any tracks that 

are associated with neutron exposure. 
Effective Date: 

December 13, 2005 

Revision No. 

0 

Document No. 

SCA-TR-TASK1-0006 

Page No. 

138 of 158 

NTS used an in-house Hankins CR-39 track-etch neutron dosimeter from 1987–2001. The 

actual MDD for the dosimeter was higher than the reporting threshold, resulting in a few false 

positives. Doses were reported down to 25 mrem. Some of these doses were probably random 

variations in the natural background in the detector systems that might get reported as 

occupational dose. In a case where the MDD is lower than your reporting threshold, then there is 

a possibility of some small occupational dose that wouldn’t be recorded. In our cases it is just 

the opposite, it would have reported a few doses as occupational that were just variations in 

natural background, because the MDD was higher than the 25 mrem used as the reporting 

threshold. 

Internal Dosimetry 

NTS relied upon in-vitro bioassay and whole-body counting (WBC) to evaluate internal dose. 

The air sampling data was not typically used, but would be more conservative if it were to be 

used. There were opportunities for percutaneous, oral ingestion, and inhalation intakes when 

coming in contact with fallout and with re-entries into tunnel complexes. This was true even 

years after the test. During atmospheric testing, when troops and support personnel rushed in, 

there was a potential for internal dose and this may not have been assessed. 

There was both a routine and event-based bioassay program. Health Physics personnel at NTS 

decided who would need bioassay based on who had the likelihood of internal exposure. 

Submittal of routine bioassay samples was either quarterly or annually. In the case of tritium, 

samples were submitted within a day or two of exposure. Event-based bioassay was used if it 

was believed there had been a potential for internal dose. The site provided 1 liter bottles for 

collecting bioassay samples. Positive bioassay results from events were rare. 

Bechtel Nevada has a subcontract to do bioassay, which has been in effect since the year 2000 

when BN implemented this new subcontract. Prior to 2000, BN and REECo earlier analyzed 

bioassay samples at the Camp Mercury analytical laboratory. The onsite lab had a large capacity 

for processing samples. Outsourcing caused a loss of some on site capabilities for sample 

analysis. NTS Radiological Health is now trying to reestablish alpha and gamma spectrometry 

capabilities. There is still some onsite capability for processing environmental air samples. 

The first whole-body counter was set up at the NRDS in Area 25, which was owned by Pan Am. 

When Pan Am went defunct, the WBC was transferred to Mercury. In the mid-1960s they also 

brought in a WBC trailer and did baselines on personnel. If personnel were on a bioassay 

program, they also had a WBC each year. WBC and bioassays were usually low. 

The original whole-body counters were sodium iodide (NaI) detectors. When they became 

available, the site switched to germanium detectors. There were no technology shortfalls with 

the program as they always had the best equipment. Money was not an issue at NTS. 

Particle size analyses were not done. They just assumed that the particles were of reparable size 

and would get into the lungs. The solubility class was based on Report of Committee 2 on 

Permissible Dose for Internal Radiation, ICRP 2, followed by Limits for Intake of Radionuclides 
Effective Date: 

December 13, 2005 

Revision No. 

0 

Document No. 

SCA-TR-TASK1-0006 

Page No. 

139 of 158 

by Workers, ICRP 30. If the particles got into the alveoli, that would be a problem with internal 

dose. 

Tritium was a concern during certain operations at the site. NTS dosimetry used metabolic 

models and bioassay to develop an infinity curve for tritium uptakes assuming tritiated water. 

This resulted in an overestimate of the dose. The methodology resulted in calculated doses that 

were greater than those determined by using ICRP 2 or ICRP 30. 

The uranium study completed in 2003 involved getting samples of urine from people who had 

lived for a period of time in communities in Nevada and Utah that were within several hundreds 

of miles of the test site. A number of communities were involved in this study. Participants 

included those on city water systems as well as on wells. This study was the basis for 

determining natural background uranium level in urine. Navarro was responsible for conducting 

the study and issued a report on their findings. 

Relationship with Outside Organizations 

There is a good working relationship between NTS and the State of Nevada personnel. Nevada 

State personnel come out and take co-samples at the very same time and at the same locations 

where NTS personnel collect their samples. 

There has been a strong EPA and earlier Public Health Service (PHS) presence at the test site. As 

federal regulations evolved, National Emission Standards for Hazardous Air Pollutants 

(NESHAPS), the Safe Drinking Water Act, and the Clean Air Act (air pollutants), all became 

drivers that affected how sampling was done at the test site. There have also been “work smart” 

standards that were developed by REECo, then BN, and now by the National Nuclear Security 

Administration (NNSA). Contractual directives and agreements have also been drivers. 

Nevada Operations has also done a public outreach program in communities surrounding the test 

site to explain the residual radiation levels and possible health effect or lack of health effects in 

cases where doses are low. The “Simon” test produced fallout over the Riverside and the 

Bunkerville area, which had very small populations. They had to establish a roadblock and 

ensure cars were washed. The “Harry” test also required roadblocks as the fallout from this test 

passed over St. George, Utah. St. George, Utah, is the most controversial in terms of offsite 

fallout. After “Harry,” they had to tell the local population to stay inside. After these tests, they 

evaluated the testing conditions and meteorology in order to prevent similar occurrences. The 

Public Health Service started offsite surveys in 1953. 

Environmental Monitoring 

There are onsite monitoring stations scattered over the site, including environmental dosimeters 

and air sampling units. The air samplers pulled in 1000 m3

 of air and could see 10-17 uCi/cc of 

plutonium. It can be seen in almost any of the samples in the Plutonium Valley area, but the 

levels are usually quite low. The site performs ambient monitoring with TLDs which they 

posted and picked up quarterly. Calcium sulfate dosimeters were used in environmental 

monitoring. These were more prone to rapid fading from ambient heating, i.e., the heat would 
Effective Date: 

December 13, 2005 

Revision No. 

0 

Document No. 

SCA-TR-TASK1-0006 

Page No. 

140 of 158 

anneal the accumulated dose right out of them. The lithium fluoride dosimeter, in terms of fade, 

was not as sensitive and produced less fading characteristics from ambient heating. Although 

there are currently some effluents at the test site, they are not very common. If they are present, 

then they are closely monitored. NTS historically had both particulate and gaseous releases. 

Historically, offsite monitoring was completed by the contractor in support of operations at NTS. 

EPA and the Public Health Service also conducted and still conduct their own monitoring. Data 

has been published covering offsite air sampling results. 

NTS used NaI and germanium detectors to count samples in a well-shielded area with an 

approved method of sample analysis for analyzing samples from air, water bone, soil and 

vegetation. 

Currently, the NTS environmental monitoring program has the responsibility of characterizing 

the various areas of the test site for residuals of contamination to ensure that DOE and Nevada 

Operations Office are in compliance with DOE orders, and EPA and Nevada State regulations. 

Their review is focused on small changes in radiological levels in water, soil, biota, and NTS 

little critters that live on the test site. Trends are evaluated in residual levels in well water and 

soil to evaluate small changes in activity; where the contamination is located, and where it is 

migrating. Both measurements and calculation methods are used to do this tracking. 

A major concern of environmental monitoring programs at the test site is that contamination of 

the water aquifers might occur. These aquifers often run quite deep and can only be monitored 

by taking samples from deep wells. The NTS environmental monitoring program, however, has 

never detected contamination moving offsite in the groundwater. The NTS environmental 

monitoring program samples the springs at Ash Meadows and Beatty area, which are near the 

California-Nevada border. To date there is no evidence of test site contamination reaching this 

area, but regulations demand that DOE and Bechtel Nevada continue to monitor this area 

thoroughly for any possible change in this status. 

There was an annual requirement to monitor for 226Ra and 228Ra to make sure they were below 

the drinking water standards. There did not seem to be an issue. 

There are some hot wells on the test site that still have levels above the drinking water standard 

of 20,000 pCi/l. These wells may also contain other residual contaminates related to the testing 

era. However, those who monitor the test site know where they are and have seen little if any 

migration. More recently, environmental monitoring is no longer done on a regular basis, but is 

accomplished only once in a while to confirm that any residual test site contaminants have not 

migrated. 

There was a tritium issue in Area 5, but at very low levels. The environmental group did some 

air samples and analysis to determine airborne concentrations. Radiological Health was seeing 

tritium bioassay results on people that were indicative of E-08 or E-10 μCi/ml. Environmental 

sampling indicated a level of E-09 μCi/ml. It dovetailed very nicely with the bioassay data and 

the models for interpreting the bioassay data. 
Effective Date: 

December 13, 2005 

Revision No. 

0 

Document No. 

SCA-TR-TASK1-0006 

Page No. 

141 of 158 

Dose from soil or other material resuspension is not a problem. Plutonium Valley is an excellent 

example. When the issue of what was happening with plutonium came up at the NTS, it was 

looked at closely. What remains after testing are large particles. Radioactive material gets 

bound up in the soil. There isn’t fine dust out there to disturb and therefore no fine dust erosion. 

NTS doesn’t have sufficient rain to wash the plutonium into the soil. The plutonium stays in the 

very top layer of dirt. Even with wildland fires that occurred in Areas 20 and 30, plutonium does 

not seem to get disturbed. It is not in a form that can be resuspended quickly. Some plutonium 

was removed in cleanup activities. 

Aerial surveys are available for the test site starting in the late 1970s. The beta/gamma 

signatures are more extensive on the site; however, there are areas with beta, gamma, and alpha 

contamination. Americium is used to identify the existence of plutonium in the aerial surveys. 

These surveys have a minimum detectable level of about 50 pCi/gram. Readings seen at the test 

site can range from below detection up to tens of thousands of pCi/gram right after a detonation. 

Beta and gamma residuals around the site of atmospheric tests are still detectable today. Area 18 

has a relatively small gamma signature for example. It may not be recognized that plutonium 

contamination is the primary hazard at these sites, and some workers might have been allowed 

into these areas with proper monitoring. “Trinity” glass is still present at the major aboveground ground zeros. “Trinity” glass can be a gamma and especially a beta hazard. 

Nuclear Reactor Rocket Program in Area 25 was responsible for running a reactor above ground. 

There were numerous failures of rockets which led to dispersal of fuel fragments and metal 

debris. These reactor rocket tests did leave a gamma signature on buildings, on flat surfaces of 

concrete, and on piping. But it is mainly on flat surfaces and soil areas that gamma signatures 

can still be found. DOE’s primary goal with this area is to stabilize it and put it under legacy 

management. 

The Desert Research Institute has conducted soil sampling and in-situ measurements at the test 

site also. The data from both analyses are being compared to evaluate the coordination between 

aerial surveys and soil sampling. 

It is important to note that although access to ground zero from one test may have been limited, 

many tests were detonated in areas with almost the same coordinates. In review of the test dates 

for particular areas, it is noted that detonations could be as close as one day apart. This meant 

that set up for subsequent tests was taking place within days of the previous event. For example, 

at the T-7 site, “Baker” was set off on October 28, 1951, “Charlie” was set off on October 30, 

1951, and “Easy” was set off on November 5, 1951. In total, 30 events were conducted at this 

location from 1951 thru 1958. These tests were done in close proximity of one another. Thus, 

the potential for exposure to previous test(s)’ residual radiation or contamination was often 

possible. 

Contractor personnel would work at these sites to install experiments, build towers, or balloon 

supports before the detonation. They could be tasked to remove debris and reinstall structures 

for the next test very soon after the previous event. Radiation safety personnel were responsible 

for taking pre- and post-detonation exposure rate surveys. Limited access to these historical 
Effective Date: 

December 13, 2005 

Revision No. 

0 

Document No. 

SCA-TR-TASK1-0006 

Page No. 

142 of 158 

records show that pre-event dose rates could be several mR/hour as a result of multiple tests 

being conducted in the same area. This work posed a potential for external dose from 

contaminated soil, as well as internal dose from inhalation of resuspended soil. 

There have been animal studies evaluating internal and external dose at NTS. Data indicated that 

for atmospheric tests, for close-in fallout, that the external dose was 2 to 3 magnitudes higher 

than the internal dose. Thus for onsite doses in this era, if you controlled the external dose, you 

controlled the internal dose. 

Incidents 

In 1963, at the underground test, “Yuba”, a tunnel test was conducted and re-entry personnel did 

receive dose from the iodine exposure. The recovery was initially conducted during the day shift 

and personnel did the recovery in self-contained breathing apparatus. However, during the 

graveyard shift, radiation safety monitors found the iodine contamination by using radiation 

monitors known as “friskers.” Personnel involved received whole-body counts following the 

event. This resulted in a Type B investigation. 

In January 1956, Los Alamos did a series of one-point detonation safety tests called Project 56. 

The fourth safety test conducted for Project 56 went slightly critical and the event was 

considered a major incident. Plutonium was dispersed over the area. There are some claimants 

associated with this test. 

In Area 12, they had a fire where there was concern of potential resuspension of fallout, but there 

was no measurable resuspension. It burned out through one of the muck piles outside U12GTunnel. U12G experienced a couple of blowouts. An extensive set of measurements and 

samples were brought back for analysis and the analysis showed that there was measurable 

resuspension. Tunnel blowouts may have resulted in some internal dose. There was also a fire in 

Area 30 during 2005. It was stopped before it developed into a blowout. 

There was an accident during the change-out of a 1,000 Ci Cs calibration source in the facility in 

CP-50. The source was shielded in 30 feet of water in its operational configuration. During the 

change-out of the source, it was dropped while the crane was lowering the source into the 

shipping cask, and the outer container separated into two pieces. The source was contained 

within a stainless steel capsule within an aluminum shell around the capsule. A worker thought 

the source was in the lower container when, in fact, it had gotten up into the upper lid cap. When 

the cap came off, and the Cs source fell, the area became a high radiation area. He held the 

cesium source for 2.8 seconds and received a dose of 1200 rem to his hand and a nine rem 

whole-body dose. Blood samples were sent to Oak Ridge for cytogenetic studies. The Oak 

Ridge estimated dose of less than 13 rem agreed favorably with the NTS estimates of 9.1 rem. 

Surprisingly there was no reddening or hair loss. 

There was an outdoor process underway on the BREN (Bare Reactor Experiment Nuclear). An 

incident occurred at the time that the BREN Tower was being moved from Area 2 of the NTS to 

the NRDS. An experimental space research reactor blew up at the NRDS site and created a 

potential for high internal doses. Parts of the core spewed out all over the experimental area. 
Effective Date: 

December 13, 2005 

Revision No. 

0 

Document No. 

SCA-TR-TASK1-0006 

Page No. 

143 of 158 

Exposure in air was over 1000 R per hour. The exposure levels were monitored with a 

teledetector. Fortunately, no personnel received any appreciable dose from this event, since 

those present were behind shields when they began to search for the pieces of the core. 

Baneberry Test 

On December 18, 1970, the “Baneberry” test resulted in a large venting to the atmosphere. 

Fissures in the rocks around the vertical shaft let water and gases escape from the cavity. Gases 

went around the ground zero casing device. With previous tests, they had evacuated the Area 12 

Camp; however, they decided not to during the Baneberry Test. The thermal blast heated up the 

mountain face and the winds that were sucked up circulated back around to Area 12 Camp. 

Some 200 test site, laboratory, and maintenance personnel were involved. 

Only the HP personnel who were going to be closer to the test site were wearing Anti-Cs. They 

tried to warn the Control Point that there would be a radioactive cloud coming toward the Area 

12 Camp. Control point personnel didn’t, however, believe that there could be a cloud coming 

that way and did not sound the alarm. The Area 12 personnel were still in camp as the cloud 

passed by. It took an hour to evacuate about 200 people as soon as they realized that personnel 

were receiving a submersion dose. 

They took all the Area 12 Camp personnel to a decontamination pad where they had 

decontamination showers located. When going thru decontamination showers, the HP personnel 

found that the areas of greatest contamination were on the hair on the back of their heads, on 

their hands and their moustaches. Most contamination was the result of noble gases. They used 

rubber gloves over their hands to induce sweating and draw contamination out of the pores of 

their skin. 

Personnel were instructed to provide urine samples. Thyroid checks for 131I were performed 

soon after the accident. Personnel were then taken downtown to the University of Nevada at Las 

Vegas where they each received a whole-body count. Doses to the Area 12 Camp personnel 

ranged from zero to 700 mrem. Personnel inside trailers at the time received the lowest doses. 

Security guards surrounded the Area 12 camp to ensure personnel did not re-enter the area. 

Some of the guards and health physics staff were in the area for the entire day during and after 

the fallout cloud passed over Area 12. 

A class action suite followed this event which had the security guards and others as part of the 

class. The Department of Justice came out to help and these lawsuits went on for years. There 

was a split decision on the jury. They felt DOE was at fault, but could not prove that the 

illnesses or deaths claimed by the plaintiffs were related to the event. It was later appealed. The 

class action suit started with several hundred class action claimants, but it was later reduced to 

about 6 claimants. 

As a result of this occurrence, testing was discontinued for six months while they reviewed the 

geology and issues associated with the venting. There was approximately 6,000 curies of 

radioactive material that vented to the atmosphere. In general, the earlier tests were more 
Effective Date: 

December 13, 2005 

Revision No. 

0 

Document No. 

SCA-TR-TASK1-0006 

Page No. 

144 of 158 

problematic than later tests. As time progressed and more knowledge about testing was 

obtained, the frequency of exposure events decreased. Investigations of venting incidents helped 

perfect the containment system and prevent venting through cracks or fissures. 

Records 

There was a considerable effort to consolidate all NTS and the Pacific Proving Grounds (PPG) 

dosimetry records in what was originally called the Dosimetry Research Project (DRP), now 

known as the Nuclear Testing Archive, operated by Bechtel Nevada for the NNSA. The records 

are under the control of the U. S. Department of Energy and were sent to a GSA-leased NNSA 

responsible space in a Desert Research Institute building. In addition to site records, records 

were retrieved from LANL and various archives when it became evident that data was missing. 

Hardcopy radiation exposure records and actual film from dosimeters are available for NTS 

workers. In 1957 electronic data files were developed to store dose information. There was a 

change in databases in 1980. Although exposure histories are fairly complete, there are some 

gaps. For example, Sandia maintains records generated for the Tonopah test. Tonopah 

dosimetry, however, is not part of the NTS dosimetry database system. 

BN has rosters of all the dose records for individual NTS workers and military personnel who 

received dosimeters. BN went through the REECo Radiological Safety Field records on 

microfilm and created a database that indicates the names and the microfilm location of 

information for a particular person. This is known as the Historical Records Center (HRC) data. 

This also contains information on test individuals who may have been associated with the NTS 

tests. This system allows BN to find the data very quickly. Records for LANL, LLNL, and the 

military are available through the Nuclear Test Archive (NTA) (i.e., those from test series 

“Ranger”, “Tumbler-Snapper”, and “Upshot-Knothole”). 

These dose records are important sources for the doses to AEC and laboratory personnel as well. 

Additional information about AEC and laboratory personnel can be found in the DNA NTPR 

reports for the NTS tests. Another good source of the radionuclides at each NTS test is in the 

growth and the decay of these radionuclides found in the publications and more formal reports. 

The BN Nuclear Testing Archive has a list of all NTS incident reports. They are well 

documented and since there was no Privacy Act at that time (prior to 1974), the information 

usually made it into the press. There is also documentation in the open literature about incidents 

at the NTS. In the case of occurrence reports or significant incidents, information in incident 

reports is extremely detailed. There are photographs, blood tests, source information, and film 

badge and/or TLD data for each person involved. Incidents occurring prior to the time REECo 

took over may be at LANL or LLNL. Many reports from the laboratories are available through 

NTA. 

By 1961, the test site implemented the use of a Form AEC 190, for external dose and a Form 

AEC 191 for internal dose. A summary report of the data from these forms was submitted to the 

AEC annually. All DOE sites provided the information to DOE Headquarters and its processors. 

The internal dose form was not supplied when there were no internal exposures. The report 
Effective Date: 

December 13, 2005 

Revision No. 

0 

Document No. 

SCA-TR-TASK1-0006 

Page No. 

145 of 158 

breaks people down by company and exposure categories. Information similar to the recorded 

exposure data on the Forms AEC 190 and 191 were later used in the development of the current 

DOE Radiation Exposure Monitoring System (REMS). The DOE REMS dosimetry system 

information was published as annual dosimetry reports starting in the early 1970s. These reports 

have now all been converted electronically into the REMS electronic dosimetry system. 

Some of the doses were only available in operations logs but not in dosimetry records. 

Operations logs are located at LLNL but these operations logs have not been found. They are 

likely held in the Defense and Nuclear Technology Directorate and/or the Engineering 

Directorate. These logs might also be available through the Archive Group at LLNL. NIOSH 

should review this. Access may be a problem due to classified material and need-to-know. 

Many of these operations logs would likely require a Sigma 14 and 15 clearance for areas where 

they might be stored. 

One more gap for potential missed dose occurred in the mid-1950s. One site expert has some 

original records. Archives do not have them. These records have the actual dose people got and 

include both film badge and extremity dose. Some of these early dosimetry records are preREECo for early contractors like American Federated Services. NTS at Mercury would like to 

transfer these original records through the University of California to LLNL for permanent 

archiving. However the process has been found to be cumbersome and attempts to do this have 

not succeeded. LLNL won’t allow transfer of these records from the possession of the NTS 

Mercury site. These are original sheets that should have been sent to LLNL for the period from 

1956–1959. 

There are event reports that cover the experimental information on detonations which include 

operational air sampling. Each test has a safety report associated with it. These should be 

available through NTS or the National laboratories. These reports should contain exposure rate 

survey information for the pre-event and post-event operations conducted. There may be some 

dose information in these reports. This information may be useful to determine the dose rates 

and contamination levels at locations for those workers supporting pre-event construction 

activities and subsequent post-event clean-up and construction activities for the next event. 

Other data that is pertinent to AEC and laboratory personnel is air sampler data and cascade 

impactors data, which was useful in determining particle size. Fallout trays, sticky paper, and 

gummed film were also used for collecting particles for analysis. 

The U. S. Department of Energy, Nevada Operations Office, produces two major reports 

annually documenting environmental monitoring at the Nevada Test Site. These two annual 

reports are the Nevada Test Site Environmental Report (NTSER) and the NTS NESHAP Report. 

The requirements for annual site environmental reports (ASERs) go back to about the mid1970s. There have been many environmental studies and reports that extend back to the 

beginning of testing at the NTS. The EPA Las Vegas office (Public Health Service) and the 

Desert Research Institute (DRI) have also been involved in monitoring and publishing reports on 

the NTS. 
Effective Date: 

December 13, 2005 

Revision No. 

0 

Document No. 

SCA-TR-TASK1-0006 

Page No. 

146 of 158 

The NESHAP report sent to EPA annually is provided to document compliance with 40 CFR 61, 

Subpart H. The compliance dose limit is 10 mrem/year, with monitoring required if the expected 

dose might exceed 1 % or 0.1 mrem. Dose monitoring is performed using EPA CAP-88-PC to 

estimate offsite dose. This is a straight line Gaussian model for particles (not meant for gasses 

such as tritium). EPA is in the process of approving an updated gaseous model soon. EPA 

approved a Nevada Safety Operations (NSO) plan for boundary receptor air monitoring in place 

of offsite air monitoring for compliance. EPA, now associated with DRI, conducts oversight 

“stakeholder” air monitoring offsite with support from public volunteers at community stations 

(Community Environmental Monitoring Program). NTS environmental monitoring personnel 

work with DRI at the community locations and assist in public “outreach” meetings to answer 

question concerning NTS and its current environmental monitoring program. 

The Weapons Test (WT) 1488 report done by the University of California at Los Angeles has 

information about fallout doses over time. This includes particle size versus distance, as well as 

fractionation that occurred as you got farther away from the test. There is also environmental 

data for the Tonapah tests done offsite. 

In 1954, the AEC did a major review of NTS Test Operations and published a classified review 

of the operational future of NTS. This review described the operational future of what type of 

tests would be conducted at a continental test site. It reviewed the type of test, acceptable 

weather, and conditions that would be considered appropriate for future tests at the test site. 

There have been several periodic major reviews of the test site by the laboratories. 

Unauthorized Practices 

Early supervisors (1950s and 1960s) indicated that some personnel got concerned about 

exceeding the AEC guidelines and would sometimes not wear their badges. If workers exceeded 

the 3 rem per quarter, they were moved to another work location or reduced-in-force (RIF) if not 

needed for the rest of the quarter. Workers looked at this as an employment problem and they 

would not wear their badge when they got close to the administrative limit. There were 

numerous incidents where Radiation Control Technicians had to tell individuals to retrieve their 

dosimeter when they showed up without it. Some personnel may not have worn their badges in 

the early days of testing, since it was up to the individual to wear the badge. This ceased when 

things tightened up starting in the later 1970s. It was hard to verify whether individuals wore 

their badges because they were worn under Anti-Cs. 

There were reports of individuals purposely taking off their film badge and shielding it while in a 

contaminated area. One person was reported to have put his badge in between two lead bricks 

with a hollowed out section in the bricks and keeping it in his vehicle so there would be no 

exposure whatsoever. Even rocks in the back of the truck were reportedly used to shield the 

dosimeter and this was an easier way to do the same thing. This practice has not been reported in 

the last 40+ years. If an employee was caught doing this, he would be punished up to 

termination and it would be documented in their personnel file. 

People did not try to purposely abuse their film badges. But, if they left their film badge on the 

windshield and they later used it, radiation safety personnel were quick to detect the pattern of a 
Effective Date: 

December 13, 2005 

Revision No. 

0 

Document No. 

SCA-TR-TASK1-0006 

Page No. 

147 of 158 

heat damage and they would determine the individual’s dose based on the exposure levels 

encountered by his co-workers. 

Medical Exams and X-rays 

At one time in the 1980s and maybe early 1990s, REECo offered annual physicals to all 

employees who wanted one in addition to the “required” physicals for many employees. 

Sometime in the early 1990s, this was changed to 1–3 years (or maybe 1–5) depending on the 

employee’s age. In the past, from medical chart review, most of the physicals included hearing 

evaluation, physical evaluation, and any age-related testing (i.e., EKG, etc.), and it appears that 

lab tests and x-rays were also done. NTS requires physicals for those in positions that require 

participation in a surveillance program or have specific job requirements (e.g., respiratory 

protection, asbestos, etc.). These physicals include hearing, EKG (age-dependent), vitals, a 

physical exam, lift assessment, vision, labs, and x-rays. The testing is dependent on the specific 

job requirements. Pre-placement physicals are done only one time at the beginning of 

employment. X-rays may also be done at the opinion of the provider. Not all NTS personnel 

currently receive physicals. 

Medical exams for laboratory personnel are done by the individual groups currently. It is 

presumed that they would have the records. Current staff does not know the practices of the 

past. 

In the past, x-rays were done at the site. Currently, the services of Insight Mountain Diagnostics 

in Las Vegas are used. It is unclear whether photofluorography was conducted at the site. 

Current medical staff indicated 4” x 5” films were not used. Data on the exact make and model 

of historic x-ray equipment is not readily available. General Electric may have manufactured 

older x-ray equipment. An outside vendor is responsible for x-ray inspections. 

Based on the knowledge of the present medical staff, Diethylenetriaminepentaacetate (DTPA), 

Prussian Blue, and Potassium Iodide have not been administered to NTS staff to prevent the 

uptake of radionuclides in the body. If these procedures did occur, the information would be 

documented in the medical record. 

Miscellaneous 

Since the inception of the EEOICPA, NTS has been involved in pulling records that would be 

useful in supporting claimants. NIOSH requests claimant information and technical reports from 

the BN NTA. Requested data is compiled and provided to NIOSH for use in dose 

reconstruction. NTS has a complete list of all claimants for which they have provided 

information. 

The BN NTA has provided NIOSH with the following reports to date. 

• DNA Nuclear Test Personnel Review (NTPR) Reports 

• Test Series Radiological Safety Reports and Reactor Radiological Safety Reports 

• Annual Environmental Reports. 
Effective Date: 

December 13, 2005 

Revision No. 

0 

Document No. 

SCA-TR-TASK1-0006 

Page No. 

148 of 158 

• Laboratory & Field Procedures 

• Relevant Animal Studies 

• Historical Summaries 

• Harry Hicks Reports (in growth and decay of fission products over time) 

• HRC Collection Indices 

• NESHAP Data 

• Technical Basis Documents (internal & external) 

The first claim associated with the “Yuba” incident was recently processed and the information 

associated with the “Yuba” event and its investigation was provided to NIOSH as part of this 

individual’s response package. 

Although the BN NTA has a list of all NTS incident reports, NIOSH has not shown interest in 

incident reports compiled. If a report is needed for an individual claimant, they may request the 

report. There are also valuable Science Applications International Corporation (SAIC) 

NTPR-related reports applicable to atmospheric nuclear testing era that have not been requested. 

To determine AEC and laboratory personnel exposure, it is important to understand the 

appropriate job title. The job title of being a laborer is different in atmospheric testing than it 

was during the underground tests. The atmospheric test laborers were used in recovery and did 

receive dose in 1952, 1953, 1955, and 1957. In the underground testing program, the laborers 

were usually not used in the recovery. A job title in the tunnel test era called the “bull gang” 

and “miners”, however, could be used in tunnel recoveries. But the job title “laborer” by itself 

would usually be a person who was not involved in recoveries for the underground tests. When 

using the old NTA film, it was also important to know the individual’s job. It is often necessary 

to use other data to determine the dose. 

Family members of scientists were invited in the past to visit the Nevada Test Site. They were 

shown the “Sedan” crater, which resulted from a 100 kiloton nuclear shot. They were only able 

to stand on the platform for a limited amount of time (~10 minutes) due to the dose rates in the 

area. 
 

 

Effective Date: 

December 13, 2005 

Revision No. 

0 

Document No. 

SCA-TR-TASK1-0006 

Page No. 

149 of 158 

ATTACHMENT 5: SUMMARY OF INTERVIEW WITH WILLIAM J. 

BRADY, PRINCIPAL HEALTH PHYSICIST (RETIRED) 

A draft summary of this interview was sent to Mr. Brady for editing two times, once by fax and 

the second time by FedEx. Mr. Brady returned it with approval of content by fax the first time 

and FedEx the second time, with approval of content. He also gave his permission to publish his 

name with the interview. The interview was conducted by Arjun Makhijani of SC&A. 

Arjun Makhijani provided an overview of SC&A’s role, which was to provide technical support 

to the Advisory Board on Radiation and Worker Health regarding issues relating to EEOICPA, 

and informed Mr. Brady that this interview was part of SC&A's review of the NTS Site Profile. 

He also informed Mr. Brady that this is an unclassified interview. He asked Mr. Brady if he had 

been contacted or interviewed by NIOSH or its contractors in regard to dose reconstruction 

issues associated with the Energy Employees Occupational Illness Compensation Program Act. 

He said he had not.5 

Background 

Mr. Brady worked at NTS from January 1952 – that is almost since the beginning of AEC testing 

operations at NTS – and he retired in July 1991. He later was on three National Academy of 

Sciences committees regarding dose reconstruction, film badges in atmospheric testing, and 

evaluation of the U.S. Army TLD. He participated in 89 atmospheric tests and hundreds of 

underground nuclear tests and is very familiar with radiation safety programs at NTS since the 

time he started work there, both as a representative to the military services and to the AEC and 

contractor side. He held various positions at NTS over the years, including security operations 

officer responsible for clearing areas of personnel before each atmospheric test in 1953 and 

1955, and retired as Principal Health Physicist. Because of his extensive experience, he was 

assigned to the Defense Nuclear Agency at the request of Vice-Admiral Monroe, then-Director 

of the Defense Nuclear Agency, assisting DNA contractors in writing 40 volumes of nuclear test 

histories and providing much information on DOD participation in atmospheric testing. He 

attended all monthly and other Nuclear Test Personnel Review (NTPR) meetings, except one, 

over a period of almost 15 years. 

Mr. Brady was also involved as director of the REECo Rad Safe reactor program. He worked 

for Reynolds Electrical Engineering Company (REECo), Inc., for some 35 years at NTS and in 

Las Vegas. (REECo was bought out by EG&G Inc., and disappeared as a DOE/NV contractor.) 

Next he was director of the Rad Safe Lab. Then he was senior HP and technical advisor of the 

Department responsible for Environmental Sciences. Then he was principal HP in the Division, 

including seven departments. In all that time he also did special assignments. He said he was 

assigned to the tough ones because they needed someone who really knew what was going on. 

He helped Dr. Barton C. Hacker with the official history of the Rad-Safe Program, published as a 

government award-winning book entitled Elements of Controversy, and another, The Dragon's 

5 According to NIOSH, a consultant to its contractor, Richard Griffith, contacted Mr. Brady by fax and 

phone (Attachment 3). Mr. Brady recollects a call from a Richard Griffith but does not recall that he said he was 

with NIOSH or NIOSH contractors or any details of the conversation that referred to NTS. 
Effective Date: 

December 13, 2005 

Revision No. 

0 

Document No. 

SCA-TR-TASK1-0006 

Page No. 

150 of 158 

Tail. Dr. Hacker did two interviews with Mr. Brady for his book, Elements of Controversy. The 

interviews included discussion of health and environmental issues at NTS and offsite. 

Overview 

NTS was a very complex site and many things went on there. There are many stories to tell and 

much detail that needs to be related. Mr. Brady felt that this interview only scratched the surface. 

There are about 800 contractors and subcontractors, from large contractors to companies that 

contracted to do sheet metal work and pour the concrete. 

From 1952 onwards, the test organization and the Signal Corps were responsible for radiation 

safety in the initial years. They used Los Alamos film badges. Not everyone was film-badged. 

It was after the TEAPOT series that REECo took over the Rad Safety program and got more 

orderly. All personnel were required to have film badges from 1957 on at NTS and from 

[Operation] Redwing on in the Pacific. Mr. Brady designed the integrated ID-and film badge 

that was worn at NTS for 26 years. The film badge report was dated 1967, but the film holder 

was worn from about 1963 on. Since all workers had to have an ID, they also all had film 

badges whenever they entered the site. From 1957 on, everyone who entered the test site was 

monitored for external dose by wearing color-coded monthly film badges that security officers 

checked before entry was allowed at the main gate to NTS. 

The film badge program was sound. Bill Horn was very thorough. The members of the NAS 

committee that I was on were amazed at what Bill Horn had done from 1956. Mr. Brady 

compiled a list of dosimetry and calibration procedures during atmospheric tests for the 

committee. A copy can be made available. (Mr. Brady has one.) 

Early Days: Atmospheric Testing Program 

REECo Rad Safe personnel went toward ground zero in pickup trucks after each atmospheric 

shot was fired. They preceded the armed forces personnel, so that they could ensure that soldiers 

avoided highly contaminated areas as much as possible. The problem was that the military 

maneuver troops stayed in the contaminated areas too long. 

The Marines walked to ground zero. The Rad Safe monitors had their own pickup trucks, but 

many times they got stuck in deep sand. Laborers and people who picked up equipment, 

electricians, and contractor people, would go in too. They would stop where the road was 

impassable and walk the rest of the way, the last several hundred feet. They were pretty close to 

ground zero because they sometimes had to winch out the cable attached to the experiments. They 

may have had to cut the cable and get the equipment out any way they could (dash in, grab the 

experiment, and run out). 

The initial fireball of the tests was not the problem in terms of large radiation exposures. It was 

the shock waves after that—one, two, even three—that brought highly contaminated dust with 

them. The shock waves raised a tremendous amount of radioactive dust, as high as 100 meters. 

The contaminated dust from previous tests could hang in the air for a day or two as respirable size 

particles. That was a problem. This occurred in many atmospheric tests. 
Effective Date: 

December 13, 2005 

Revision No. 

0 

Document No. 

SCA-TR-TASK1-0006 

Page No. 

151 of 158 

For example, after a nominal (10 to 100 kT) shot, the shock-wave wind reached 180 miles an hour 

at one mile. AEC employees and their contractors who went in after the shot any time within a 

day or two were subject to the same conditions. The problem of internal dose has been neglected. 

So, the initial assumption that internal doses from the tests were not high was not correct. 

The immediate gamma exposures when personnel walked in were from sodium-24 and 

manganese-56, which are short-lived neutron-activation products, but there is also exposure from 

resuspended fission products from prior tests. The resuspension of fission products and 

unfissioned material, including plutonium and other fissionable materials, deposited from prior 

tests was created by the dust resuspended by the current test. How much was resuspended 

depended on the type of device tested. So we are talking about strontium-90 and a few other long 

half-life radionuclides. 

In the fall of 1955, there were four safety shots at NTS, called “Operation 56,” in which kilograms 

of plutonium were spread all over the place. Personnel entered the areas in 1956, mined the 

plutonium, and put it in 55-gallon drums for recovery at Oak Ridge. There was a truck accident on 

the way, which presented contamination problems. 

There was no bioassay capability at NTS and no bioassay in the early days. Los Alamos did a few 

samples for plutonium in 1956, but very few. They were finding positive results. What the results 

meant, he was not sure. The personnel were dressed in rubber suits and had supplied air; even so 

they were getting contaminated. LANL was getting positive bioassay results, but I am not sure 

whether they were contaminated or not. There was a problem of cross contamination of samples. 

Conditions varied from one test to another a great deal. It was complicated. When Floyd W. 

Wilcox, deceased in 2004, took over as Superintendent of the Rad Safe Division, he made Mr. 

Brady head of the training branch and historian in late 1956. 

Monitors had to respond to laborers and scientists alike; so they had to be special people. Mr. 

Wilcox's books and papers referring to these problems and some of Mr. Brady's papers are at the 

atomic museum in Las Vegas, and some of them speak to the early requirements for hired radiation 

monitors. 

The number of Rad Safe people in some tests was large; in others it was not. For operation 

Plumbbob, there were 130 Rad Safe people from the AEC and contractors and a similar number 

from the military. Thus, there were over 200 employees and military types involved with the Rad 

Safe program for Plumbbob. There were over 2,000 Marines on maneuvers plus other military 

personnel. The Rad Safe people went in front of the marines so they could keep the marines out of 

the really hot areas. But there were only 39 people in Rad Safe during Hardtack II and everything 

was hurried up. As one result our monitors could not say in long and get “burned out.” 

Rad Safe personnel did many different kinds of work. There were Rad Safe people on all flights 

after atmospheric tests except the flights whose mission was cloud sampling. Mr. Brady once flew 

through the cloud after an excavation shot whose mission was to seed it with condensation nuclei 

to induce rain. They did induce rain but could not eliminate the cloud fully. 
Effective Date: 

December 13, 2005 

Revision No. 

0 

Document No. 

SCA-TR-TASK1-0006 

Page No. 

152 of 158 

In regard to decontamination of the aircraft, Mr. Brady said that it was the Rad Safe monitors who 

did it at NTS and the rest of the aircraft went to Indian Spring Air Force Base, and the military 

decontaminated them there. Mr. Brady's Rad Safe people from the lab were down there at Indian 

Spring to decon the air crews. Air Force personnel used an inch-and-a-half fire hose. The engines 

would get very hot [radioactive] and they were hard to clean. They would run the engines up and 

put high pressure water through them. The engines were 50 to 100 R per hour initially. They 

would get them down to 4 to 5 R/hr. Then they would park them to let the short-lived 

radionuclides decay. 

Internal Dose: Tritium 

In the early years, the focus was mainly on external dose. There was not much internal monitoring 

until the fall of 1955, when LASL did some plutonium urine analysis. Then there were some 

plutonium bioassays. In 1958 there was some tritium monitoring. At one point there were big 

exposures of tritium. In one 1961 shot, there was a steam explosion and it blew up the E-Tunnel 

complex. There were to be multiple tests there. It was ready to go when it got contaminated. We 

did decontaminate it. In the meantime, the workers were used in B-Tunnel. E-Tunnel was 

vacuumed out. NTS Rad Safe personnel did not know where the tritium was coming from. It was 

vented to the atmosphere after we found out which shot sites the tritium was coming from and we 

drilled holes from the top of the mesa to vent the tritium from the top of the mesa. The original 

tritium sniffer instruments would go off-scale at the tunnel portals because of the radioactive noble 

gases. After the exposures in E- and B-Tunnels, Mr. Brady developed a more reliable method of 

tritium monitoring using anhydrous barium sulfate to absorb some of the water from the tunnel air 

for analysis. 

E-Tunnel was first vacuumed, and then washed down with a 60-foot 2-inch pipe. A berm was 

built and the water pumped into Haynes Lake. That is how the Haynes Lakes were formed. 

There were two Haynes Lakes, containing a lot of tritium. 

Mr. Brady said that there was tritium in B-Tunnel and that they had burned out the 

decontamination personnel in E-Tunnel. The tritium exposures in this incident were big, from 5, 

10, to 20 rem primarily to Rad Safe personnel. In the fall of 1961, 108 miners were also exposed 

in E-Tunnel and then B-Tunnel. The documentation of the doses is in the records. The NTS Rad 

Safe laboratory compiled a list of the exposed personnel every week and was having a difficult 

time. Finally AEC-Washington sent an Ivy-League type to investigate why NTS was having 

these overexposures. His name was George John Keto, an assistant to General Betz, who was 

responsible for testing at NTS. 

The venting of tritium took place in the fall of 1961 and the spring of 1962. There was other 

stuff there too. If you fire a shot—an underground shot—and it does not go well, that is worse 

than if you have a good yield. In a poor shot, you don't get the molten rock. In a good shot, you 

have the molten rock to hold the radioactivity to some extent. 
Effective Date: 

December 13, 2005 

Revision No. 

0 

Document No. 

SCA-TR-TASK1-0006 

Page No. 

153 of 158 

In one case, a candle caused an explosion in B-Tunnel. Personnel were blown back a 

considerable distance toward the black door. There were eight of them. Mr. Brady 

decontaminated them. 

The real big tritium exposures occurred in 1958 at NTS. In 1959 Eric Geiger was trying to 

reconstruct them. There were microfilmed records. Mr. Brady provided each NTPR team with 

four boxes with 44 microfilms – one for each branch of the service and one for CAN/Field 

Command, Albuquerque. 

Mr. Brady thought that any values of 355 mrem per year for tritium were very low. He said he had 

written many memos and documents that referred to tritium. Project Gnome, the first 

PLOWSHARES test, 30 miles from Carlsbad, NM, had NTS Rad Safe personnel, including Mr. 

Brady. He called the test a disaster. There were water seeps in the shaft and there was also bound 

water in the salt rumored to be as much as 6%. This bound water and the seep water flashed into 

steam, rolled along 1,100 feet of drift into the Station Room after passing through the blast door, 

proceeded up 1,200 feet of shaft, including a blowout preventer, and geysered 300 feet in the air. 

Mr. Brady said he spent two 10-day trips down there to fix it. Water was leaking into the shaft. 

There was tritium in the atmosphere. There was a huge amount of tritium. There were water seeps 

and springs at various places in the drift. Mr. Brady designed a refrigeration system, with 

anhydrous calcium sulfate which effectively trapped the tritiated water vapor. Then an AEC 

representative reversed the airflow and dumped much more tritium to the atmosphere. 

Internal Dose: Other Radionuclides 

The minters were pretty heavily exposed at NTS. Wes Wilcox used at LASL to calibrate the 

counters and check the biological half-life of 137Cs by measuring his body burden. After the 

“candle” incident, eight miners and Rad Safe personnel were heavily exposed. 

NTS did not really have a handle on the other radionuclides for internal dose until late in the 

program. Mr. Brady said he started the bioassay program when he was lab director, but it was 

never fully implemented and they did not care. Is a monitor going to tell you he got an 

overexposure? They don't get any overtime that way. In addition, you got an extra hour's pay if 

you went to a forward area. 

Eventually NTS got big analyzers, 4,000 channels, to replace the single channel analyzers and the 

new lab was built. Mr. Brady said that he designed most of the lab, and that NTS had the best 

plutonium lab in the world. There were two big bell jars with 32 positions, each of which were 

used to count the samples for up to two weeks. It was all computerized. 

The new lab became operational some time in the 1960s. 

Off-Normal Practices 

If workers got “burned out” they could not go to work in the forward areas. Monitors put film 

badges into lead boxes or between 2”-thick lead bricks – that was common. At Hardtack II, there 

were 39 people in Rad Safe. They were told, “Don’t get overexposed; we don't have anyone to 
 

 

Effective Date: 

December 13, 2005 

Revision No. 

0 

Document No. 

SCA-TR-TASK1-0006 

Page No. 

154 of 158 

replace you.” Mr. Brady said he himself told them “don't get overexposed.” Some guys would 

take two lead bricks and put them in their truck glove compartment with their film badges in 

between. The whole point was not to get overexposed in 1958. Different operations had different 

problems. For NIOSH or anyone else to estimate now as to how much people got exposed at the 

test site is kind of ridiculous because there were no general rules until 1957. Even then they put 

their film badges in lead boxes. Mr. Brady had his film badge and his accompanying monitor's 

badge in between lead bricks in one initial survey. It read 800 mR when processed. We had gone 

through a fallout area close to ground zero in excess of 50 R/h gamma. 

The jobs in the forward areas paid more and so in a funny way employees were working against 

the clock and telling people that they never got exposed. 

In response to the question as to how long the problem of hiding badges in lead boxes and the like 

went on, Mr. Brady said that it was minimized in the late 1960s. 

Mr. Brady said that there are some stories beyond description. He cited the example of a person 

at the commercial Beatty low-level radioactive waste facility who was giving away hot material. 

He gave away a hot cement mixer and everything they mixed at Beatty [using that mixer] was 

hot. Perhaps some items were sold. That was in the early 1960s; 1962, 1963, 1964. 

The guy at Beatty had been in charge of decontamination at the rocket facility (Project 400) and 

he was used to hundreds of R per hour; he did not care about internal dose things. Once a scale 

that had been used to measure 90Sr at Livermore was then discarded as waste, sent to Beatty and 

then wound up in someone's home. It was located on a lady's kitchen counter. NTS Rad Safe 

and EPA personnel had to monitor and clean up the town of Beatty, including homes, tearing up 

carpets, concrete floors, etc., and our laboratory at Mercury, NM, where “hot” samples were 

brought for processing.6 

6

 In reviewing an interview draft Mr. Brady put in a note regarding personnel who were formerly at NTS 

who then went to the company that operated the Beatty facility that have been omitted here for privacy reasons. 
 

Effective Date: 

December 13, 2005 

Revision No. 

0 

Document No. 

SCA-TR-TASK1-0006 

Page No. 

155 of 158 

ATTACHMENT 6: NIOSH RESPONSE TO POST-SEPTEMBER 9, 2005, 

CONFERENCE CALL QUESTIONS 

NIOSH sent the following responses to SC&A questions (which NIOSH also reproduced) that 

SC&A sent NIOSH as a follow-up to the conference call of September 9, 2005 (Attachment 3). 

“SC&A inquired whether bomb assembly was pending as a part of the TBD, in a manner similar 

to atmospheric testing. NIOSH responded that it was not pending. SC&A then asked how 

extremity doses for bomb assembly were being handled. NIOSH responded that Dick Griffith 

would get back to SC&A about that.” 

Status: SC&A has not received the information or heard from Mr. Griffith. 

Response: Bomb assembly was undoubtedly performed by a small cohort. It would have been 

done by weapons lab (LANL, LLNL, etc.) people and not by REECo staff. Weapons lab 

dosimetry people should have addressed this issue, and it should be in their TBDs. I have been 

unable to find reference to it in the LANL TBD on external dosimetry. I have a call in to the 

author of that section. The LLNL external dosimetry section has not yet been approved. 

In view of the nature of these exposures, there are undoubtedly classification issues that would 

require an adequate clearance to address. It would seem appropriate, therefore, to formulate a 

special task involving one or more specialists with the appropriate clearance and experience to 

develop an unclassified Complex-wide guidance document on this issue. 

“Referring to Table 6.3 on page 25, Vol. 6 of the TBD, SC&A asked whether the conversion 

factor, millirem per mR [there is a typo in the table, it should be millirem per mR, not millirem 

per R] that starts out at 0.45 is for 30 KeV photons. Another question about this table was 

whether these values were for backscatter. NIOSH responded that this question should go to 

Dick Griffith.” 

Status: SC&A has not received the information. 

Response: The table in question has been moved to Appendix A in the draft Revision. In fact, 

this table was taken directly from REECo (Reynolds Electrical and Engineering Company), 

1995b, External Dosimetry Technical Basis Manual for the Nevada Test Site and Other 

Designated Locations, Report (548)-6.4.1, Las Vegas, Nevada, December – Table 5-2, Page 39. 

There is indeed a typo. It should be rem per R, as in the original table. 

The conversion factors specified in the table are prescribed in the DOELAP standard for the 

National Institute of Standards and Technology (NIST) reference radiations: NIST Special 

Publication 250-58, NIST MEASUREMENT SERVICES: Calibration of X-ray and Gamma-Ray 

Measuring Instruments, April 2001. 

The conversion factors specify the relationship of shallow and deep dose equivalent (using a 

phantom) to exposure (free in air). These factors have been weighted for each of the reference 

radiation photon spectra. The definition of personal dose equivalent includes the effects of body 
Effective Date: 

December 13, 2005 

Revision No. 

0 

Document No. 

SCA-TR-TASK1-0006 

Page No. 

156 of 158 

interaction, scatter, absorption, etc., while exposure, of course is free-in-air. Backscatter is part 

of the dosimeter response, and varies with dosimeter design and calibration conditions 

(e.g., angle of incidence). However, the conversion factors shown in this table only provide a 

basis for converting from one dosimetric quantity to another. Dosimeter backscatter response 

comes at the time of calibration. 
 

 

Effective Date: 

December 13, 2005 

Revision No. 

0 

Document No. 

SCA-TR-TASK1-0006 

Page No. 

157 of 158 

ATTACHMENT 7: NIOSH NOTES ON CONVERSATIONS WITH 

MARTHA DEMARRE SENT TO SC&A7
 

TO: File 

FROM: Lori Arent and Cheryl Smith, NIOSH Dose Reconstruction Team, Task 3 

SUBJECT: Nevada Test Site (NTS) Technical Basis Document (TBD), Chapter 5, 

Occupational Internal Dosimetry - Record of Interview with Ms. Martha 

DeMarre, Bechtel Nevada 

DATE: August 18, 2004 

The NIOSH Dose Reconstruction Team members conducted interviews with Ms. Martha 

DeMarre, the Bechtel Nevada Coordination and Information Center Manager, during September 

2003 and July 2004. The interviews were conducted in Las Vegas to support the drafting of the 

NTS TBD Internal Dosimetry chapter. 

During the week of September 8, 2003, Ms. DeMarre provided the following information which 

was incorporated into Chapter 5 of the NTS TBD: 

• 	 The 1993 Technical Basis for Internal Dosimetry at the NTS (REECo 1993) reflects 

radiological protection practices from about 1970 through the end of nuclear weapons 

testing in 1992, and is the best available source of internal dosimetry information for the 

nuclear weapons testing era. 

• 	 Radionuclides that have resulted in recorded doses above established limits at NTS are 

3

H, 131I, 239Pu, and 241Am. 

During the week of July 5, 2004, Ms. DeMarre provided the following information, which was 

incorporated into Chapter 5 of the NTS TBD: 

• 	 Tritium monitoring started in 1958 with an MDA of 5 μCi/L used for urine samples. 

• 	 Individuals who were involved in tunnel work with job classifications of miner, mucker 

(muck machine operator), “bull gang” (underground laborer), shifter, tunnel walker, 

dinky locomotive operator and who held a Q-level clearance should be assigned tritium 

dose. No worker whose employment history is intermittent (employment intervals < 5 

months) could have obtained a Q clearance and, therefore, would not have been involved 

in tunnel re-entry or emplacement of devices during events. Having a Q-level clearance 

and working in Area 1 or 12 is an indication of the possibility of tritium exposure. All 

other workers should not be assigned tritium dose. 

7

 SC&A notes that more extensive notes on NIOSH’s contacts with NTS site experts are available on its 

database that is used by dose reconstructors (as well as the Board and SC&A). 
Effective Date: 

December 13, 2005 

Revision No. 

0 

Document No. 

SCA-TR-TASK1-0006 

Page No. 

158 of 158 

• 	 NTS collected plutonium samples for 24 hours. In effect, the collection procedure 

normalized them to 24-hour samples. Screenings for all other radionuclides were 

normalized to 24-hour samples in the bioassay records. 

• 	 For iodine air sampling, bioassay records indicate if the air samples were collected with a 

charcoal canister or a filter. 

• 	 The main concerns at the NTS were tritium, iodines, and plutonium. If iodine was 

present, it was easily identified. In the case of the YUBA test (1963), even the G-M 

survey meter detected iodine present in workers leaving the controlled area. Because 

NTS did not have a Whole-Body Counter (WBS) at this time, these individuals were sent 

to Donner Laboratory (California) for a full workup (whole body and urine). The iodine 

was easily detectable in urine and in the whole body. 

• 	 Due to security concerns, the word “tritium” was not used. The terms “ACTIVITY or 

“ACT,” “MINT,” “EVERGREEN,” and “T” were code words for tritium. “PRODUCT” 

was a code word for 239Pu. “LT” or “-” in the bioassay records means less than the 

detection limit. The code “-99” means not detected. 

• 	 NTS maintains a record set called the “dead bioassay database.” There are no codes in 

this database that include information from 1955 to 1963. In the microfiche copy of the 

bioassay data, the years are listed as two digits, (e.g., 56, 57, etc.). The main purpose of 

the dead bioassay file/microfiche is to point to the raw data (note, reel, and frame 

citations). If an individual has a “deadbio” record, the microfiche page is followed by a 

copy of the original data forms for the data cited. 

• 	 Tunnel air sampling began in 1957 in locations with the potential for airborne exposure. 

Air samplers operated continuously. Radiological Control Technicians checked and 

exchanged the filters each shift. Bioassay was done only if there was an indication of an 

effluent release (e.g., positive air sample). 

• 	 The original source of tritium in the 1961 B-Tunnel exposures was from 1958 activities. 

• 	 The REECo employees that had whole-body counts after the YUBA Event, June 5, 1963, 

were sent to Donner Laboratory for monitoring. The information was supplied back to 

REECo and the AEC at the time regarding the data and data analysis (iodine exposures). 

Nine REECo personnel received thyroid doses in excess of 30 rads during YUBA.