November 10, 2006 

Mr. David Staudt 

Centers for Disease Control and Prevention 

Acquisition and Assistance Field Branch 

Post Office Box 18070 

626 Cochrans Mill Road – B-140 

Pittsburgh, PA 15236-0295 

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

for the Fernald Environmental Management Project (Feed Materials Production 

Center), SCA-TR-TASK1-0010 

Dear Mr. Staudt: 

SC&A is pleased to summit to NIOSH and the Advisory Board draft report SCA-TR-TASK1-0010, 

Review of the NIOSH Site Profile for the Fernald Environmental Management Project 

(Feed Materials Production Center). This site profile review covers the six volumes of the Fernald 

TBD; ORAUT-TKBS-0017-1 though ORAUT-TKBS-0017-6. 

This review was carried over from FY 2006. With this report, all of the tasks assigned to SC&A in 

FY 2006 are now complete. 

We look forward to discussing this draft report with the Working Group, NIOSH, and the full 

Advisory Board at any time that the Board takes up matters related to Fernald. Please let me 

know if you have any questions. 

Project Manager 

cc: P. Ziemer, PhD, Board Chairperson A. Makhijani, PhD, SC&A 

Advisory Board Members H. Behling, SC&A 

L. Wade, PhD, NIOSH M. Thorne, SC&A 

L. Elliott, NIOSH H. Chmelynski, SC&A 

J. Neton, PhD, NIOSH J. Fitzgerald, Saliant 

S. Hinnefeld, NIOSH J. Lipsztein, SC&A 

L. Homoki-Titus, NIOSH K. Robertson-DeMers, CHP, Saliant 

A. Brand, NIOSH S. Ostrow, PhD, SC&A 

J. Broehm, NIOSH K. Behling, SC&A 

L. Shields, NIOSH T. Bell, Saliant 

Project File (ANIOS/001/10) 

Sincerely, 

John Mauro, PhD, CHP 

1608 SPRING HILL ROAD, SUITE 400 • VIENNA, VIRGINIA • 22182 • 703.893.6600 • FAX 703.821.8236 
 

ADVISORY BOARD ON 

RADIATION AND WORKER HEALTH 

National Institute of Occupational Safety and Health 

Review of the NIOSH Site Profile for the Fernald Environmental Management Project 

(Feed Materials Production Center) 

Contract No. 200-2004-03805 

Task Order No. 1 

SCA-TR-TASK1-0010
 

Prepared by 

S. Cohen & Associates 

1608 Spring Hill Road, Suite 400 

Vienna, Virginia 22182 

Saliant, Inc.
 

5579 Catholic Church Road 

Jefferson, Maryland 21755
 

November 2006 

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. 
 

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S. COHEN & ASSOCIATES: Document No. 

SCA-TR-TASK1-0010 

Technical Support for the Advisory Board on 

Radiation & Worker Health Review of 

Effective Date: 

Draft – November 10, 2006 

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

REVIEW OF THE NIOSH SITE PROFILE 

FOR THE FERNALD ENVIRONMENTAL 

MANAGEMENT PROJECT (FEED 

MATERIALS PRODUCTION CENTER) 

Page 2 of 169 

Task Manager: 

________________________ Date: ___________ 

Arjun Makhijani, PhD 

Supersedes: 

N/A 

Project Manager: 

________________________ Date: ___________ 

John Mauro, PhD, CHP 
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TABLE OF CONTENTS 

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

1.0 Executive Summary ...........................................................................................................10 

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

1.2 Summary of Findings.............................................................................................11 

1.2.1 Highlights...................................................................................................11 

1.2.2 List of Findings..........................................................................................12 

1.3 Opportunities for Improvement .............................................................................14 

2.0 Scope and Introduction ......................................................................................................17 

2.1 Review Scope.........................................................................................................17 

2.2 Review Approach...................................................................................................19 

2.3 Report Organization ...............................................................................................19 

3.0 Assessment Criteria and Methods......................................................................................21 

3.1 Objectives ..............................................................................................................21 

3.1.1 Objective 1: Completeness of Data Sources .............................................21 

3.1.2 Objective 2: Technical Accuracy..............................................................21 

3.1.3 Objective 3: Adequacy of Data.................................................................22 

3.1.4 Objective 4: Consistency among Site Profiles..........................................22 

3.1.5 Objective 5: Regulatory Compliance........................................................22 

4.0 Site Profile Strengths .........................................................................................................26 

4.1 Introduction to the TBD.........................................................................................26 

4.2 Site Description......................................................................................................26 

4.3 Air Concentrations relating to K-65 Material........................................................26 

4.4 Neutron Dose Estimation .......................................................................................26 

4.5 AP Geometry .........................................................................................................26 

5.0 Findings..............................................................................................................................27 

5.1 Issue 1: Thorium-232 Exposure ............................................................................28 

5.1.1 Thorium Processing Facilities and Periods................................................28 

5.1.2 Thorium Air Concentration Data ...............................................................33 

5.1.3 Thorium Fugitive Emissions ......................................................................41 

5.1.4 Exposures from Thorium Redrumming .....................................................42 

5.1.5 Exposures due to Thorium Fires................................................................44 

5.1.6 TBD Procedure for Estimating Thorium Intakes .......................................44 

5.2 Issue 2: High-Grade Ore Processing Waste Steams .............................................47 

5.2.1 Raffinate Intake Estimation Method ..........................................................47 

5.2.2 TBD Guidelines for Estimating Raffinate Exposure .................................49 

5.3 Issue 3: Estimation of Doses from Recycled Uraniuim ........................................50 

5.3.1 Recycled Uranium Trace Contaminant Data .............................................50 

5.3.2 Recycled Uranium Trace Contaminant Radionuclide List ........................53 

5.3.3 TBD Guideline for Recycled Uranium Dose Estimation ..........................54 

5.4 Issue 4: Internal Doses due to Uranium ................................................................55 

5.4.1 Enrichment of Uranium Processed at Fernald ...........................................55 
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5.4.2 Doses to Unmonitored Female Employees................................................57 

5.4.3 Periodic Extremely High Uranium Dust Concentrations...........................58 

5.5 Issue 5: Ingestion dose..........................................................................................60 

5.5.1 Ingestion Doses and the TBD ....................................................................60 

5.6 Issue 6: External Dose ..........................................................................................61 

5.6.1 External Dose Reconstruction Protocols ...................................................61 

5.6.2 Estimation of Extremity Doses ..................................................................61 

5.6.3 Beta Dose to the Rest of the Body .............................................................65 

5.6.4 Geometry of Exposure ...............................................................................68 

5.6.5 Correction Factors during Initial Period of TLD Use ................................68 

5.6.6 Female Employees – External Dose ..........................................................70 

5.7 Issue 7: Occupational Environmental Dose: Internal – Non-radon.....................71 

5.7.1 Uranium Emissions Source Term ..............................................................71 

5.7.2 Modeling Environmental Dose ..................................................................72 

5.7.3 Exposures from Diffuse Emissions............................................................75 

5.8 Issue 8: Radon.......................................................................................................76 

5.8.1 Environmental Radon Dose Modeling.......................................................79 

5.8.2 Radon Dose from Pitchblende Ore Storage ...............................................80 

5.9 Issue 9: Occupational Environmental Dose – External ........................................80 

5.9.1 Outdoor Diffuse Emissions and External Environmental Dose ................81 

5.9.2 External Environmental Dose near the K-65 Silos ....................................81 

5.9.3 Occupational Radon Exposure...................................................................81 

5.10 Issue 10: Occupational Medical Dose...................................................................82 

5.10.1 Possible Use of Photofluorography ...........................................................82 

5.10.2 X-ray Retake Rate......................................................................................82 

5.10.3 X-ray Collimation ......................................................................................83 

5.10.4 Occupational Lumbar Spine X-rays...........................................................84 

6.0 Observations ......................................................................................................................85 

6.1.1 Internal Inconsistencies in the TBD...........................................................85 

6.1.2 Intakes and Plant Production Capacity Utilization ....................................86 

6.1.3 Bioassay Frequency and Incidents.............................................................87 

6.1.4 Uranium Isotopic Ratios ............................................................................87 

6.1.5 Frequency of Events in Thorium Overpacking Operations .......................88 

6.1.6 MDLs for Beta Extremity Monitoring .......................................................88 

6.1.7 X-ray Unit Survey Data .............................................................................88 

6.1.8 Miscellaneous Observations ......................................................................89 

7.0 Overall Adequacy of the Site Profile as a Basis for Dose Reconstruction ........................91 

7.1 The Five Objectives ...............................................................................................91 

7.1.1 Objective 1: Completeness of Data Sources .............................................91 

7.1.2 Objective 2: Technical Accuracy..............................................................92 

7.1.3 Objective 3: Adequacy of Data.................................................................92 

7.1.4 Objective 4: Consistency among Site Profiles..........................................93 

7.1.5 Objective 5: Regulatory Compliance........................................................94 

8.0 References..........................................................................................................................95 
 

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Attachment 1: SC&A Questions on the Fernald TBD sent to NIOSH .......................................100 

Attachment 2: Answers to SC&A Questions on Fernald Site Profile ........................................108 

Attachment 3: Summary of the Conference Call of August 18, 2006, on the Fernald Site 

Profile Regarding SC&A Questions Sent to NIOSH.......................................................121 

Attachment 4: Site Expert Interviews .........................................................................................139 

LIST OF TABLES 

Table 1: Plant 6 Air Dust Data, 1960 to 1962............................................................................29 

Table 2: Thorium Air Concentration Data: Fernald, 1950s and Early 1960s ...........................36 

Table 3: Thorium Dust Concentrations: 1966 and 1977...........................................................37 

Table 4: Thorium Dust Levels for Certain Operations: Fernald and Ames ..............................38 

Table 5: External Dose Rates and Surface Contamination, Thorium Metal Casting:
 

Ames vs. Fernald .........................................................................................................39 

Table 6: Lindsay Light and Chemical Company and Simonds Saw 

Thorium Air Dust Data ................................................................................................40 

Table 7: 50-Year Organ Dose Conversion Factors for U-234 and Th-232 – Inhalation ...........40 

Table 8: Comparison of Total Fernald RU Contamination, TBD, Vol. 5 vs. DOE 2003 ..........52 

Table 9: Some Examples of Corrections to Measured TLD Dose .............................................69 

Table 10. Correction Factors for Hp(10) Dose in Various TBDs ................................................94 
 

 

 

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ACRONYMS AND ABBREVIATIONS 

Advisory Board Advisory Board on Radiation and Worker Health 

AEC Atomic Energy Commission 

Al Aluminum 

Anti-Cs Anti-contamination Clothing 

AP Anterioposterior 

AWE Atomic Weapons Employer 

BZ Breathing Zone 

CDC Centers for Disease Control and Prevention 

CFR Code of Federal Regulations 

Ci Curie 

DCF Dose Conversion Factor 

DF Decontamination Factor 

DL Decision Level 

DOE Department of Energy 

DOELAP Department of Energy Laboratory Accreditation Program 

dpm Disintegrations per minute 

DU Depleted Uranium 

DWA Daily Weighted Average 

EEOICPA Energy Employees Occupational Illness Compensation Program Act 

EPA Environmental Protection Agency 

ES&H Environmental Safety and Health 

EU Enriched Uranium 

FEMP Fernald Environmental Management Project 

FMPC Feed Materials Production Center 

FY Fiscal Year 

GA General Area 

GAO Government Accountability Office 

GE General Electric 

GI Gastrointestinal 

H&S Health and Safety 

HASL Health and Safety Laboratory 
 

 

 

 

 

 

 

 

 

 

 

K-65 

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HF Hydrofluoric 

HP Health Physics or Health Physicist 

HVL	 Half-Value Layer 

ICRP International Commission on Radiological Protection 

IH&R Industrial Hygiene and Radiation Department 

IIF	 Incident Investigation Form 

IMBA Integrated Modules for Bioassay Analysis 

INEL Idaho National Engineering Laboratory 

IREP Interactive RadioEpidemiological Program 

Pitchblende Uranium Ore from Congo containing high concentrations of 

Ra-226 

LOD Limit of Detection 

MAC Maximum Allowable Concentration 

MDL Minimum Detectable Level or Minimum Dose Limit 

MIVRML Mobile In-Vivo Radiation Monitoring Laboratory – ORNL Y-12 

MCW Mallinckrodt Chemical Works 

MeV Mega-electron Volts 

MPLB Maximum Permissible Lung Burden 

mrem millirem 

mrep millirep 

mr milliroentgen 

MTU Metric tons uranium 

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 

NLO National Lead of Ohio 

NTS Nevada Test Site 

NU Natural Uranium 

NuSal Neutral Salt 

OCAS Office of Compensation Analysis and Support 

ORAU Oak Ridge Associated Universities 

OU3	 Operable Unit 3 
 

 

 

 

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PAS Personal Air Sampler 

pCi Picocurie 

PCM Personnel Contamination Monitors 

ppb Parts per billion 

PFG Photofluorography 

Piketon Portsmouth Gaseous Diffusion Plant 

POC Probability of Causation 

POOS Plutonium Out of Specifications 

PPE Personal Protective Equipment 

RAC Radiological Assessments Corporation 

RCS Radon Control System 

RCT Radiological Control Technician 

rem Roentgen equivalent man 

REMS Radiation Exposure Monitoring System 

RMI Reactive Metals, Inc. 

RTR Real Time Radiography 

RTS Radon Treatment System 

RU Recycled Uranium 

RWP Radiation Work Permit 

SC&A S. Cohen and Associates 

SEC Special Exposure Cohort 

SRPD Self Reading Pocket Dosimeters 

SRS Savannah River Site 

STC Strong tight container 

TBD Technical Basis Document 

ThF4 Thorium tetrafluoride 

ThO2 Thorium dioxide 

TIB Technical Information Bulletin 

TLD Thermoluminescent Dosimeter 

TRU Transuranics 

TTA Transfer Tank Area 

U Uranium 
 

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U3O8 Black Oxide 

UAP Uranyl ammonium phosphate 

UF4 Green Salt or uranium tetrafluoride 

UF6 Uranium hexafluoride 

UNH Uranyl Nitrate Hexahydrate 

UO3 Orange Oxide 

WL Working Level 

WLM Working Level Month 
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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 Fernald Environmental Management Project (ORAUTTKBS-0017), which was published in six volumes numbered ORAUT-TKBS-0017-1 through 

ORAUT-TKBS-0017-6, inclusive, referred to in this report as the Fernald Technical Basis 

Document (TBD), Volumes 1 through 6, or the Fernald Site Profile, Volumes 1 though 6. This 

review covers all six volumes of the Fernald TBD. It includes a review of related Fernald 

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 at Fernald (Attachment 4). 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 Fernald 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 Fernald TBD, except for Volume 4, for which Rev. 01, 

published in February 2006, was reviewed. The five Rev. 00 volumes were published between 

February 11, 2004, and May 28, 2004. Rev. 01 of Volume 4 relating to environmental dose was 

published on February 7, 2006. They represent the most recent published version of the Fernald 

TBD on NIOSH’s web site as of May 7, 2006. 

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 SC&A 2004: 

(1) Completeness of Data Sources 

(2) Technical Accuracy 

(3) Adequacy of Data 

(4) Consistency among Site Profiles 

(5) Regulatory Compliance 

1.1 SUMMARY OF STRENGTHS 

(1) Volume 1 of the TBD gives a very helpful overview of operations at Fernald without 

going into technical detail. Volume 2 provides a useful description of Fernald on a plantby-plant basis, and within that by processes and activities, followed by radiation sources. 

It is helpful and takes the reader through site operations in a coherent manner. 
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Furthermore, it is useful to group waste management facilities, activities, and processes, 

and discuss them after the presentation of operational aspects of the site. The summary 

of Fernald Environmental Management Project (FEMP) radioactive materials and 

characteristics is properly placed at the end of the document. 

(2) The recommendations with respect to neutron dose reconstruction have been well 

documented, and make a number of claimant-favorable assumptions. 

(3) Available (sparse) data for radioactive dust concentrations (non-radon) during the loading 

of the K-65 Silo 1 have been used in a claimant-favorable way in the suggested dose 

reconstruction procedure; however, there are other aspects of K-65 raffinate dose 

estimation procedure that are not claimant favorable (see Findings 7 and 8). 

(4) The use of the anterioposterior (AP) geometry for all working conditions and radiation 

fields is claimant favorable and is a positive part of the document. 

1.2 SUMMARY OF FINDINGS 

1.2.1 Highlights 

There are some points worth highlighting broadly from the 33 findings below and the analyses 

pertaining to them in Section 5 and Section 7 of this report. 

•	 The thorium data in the TBD are particularly incomplete in regard to what is available 

and, as they stand, inadequate for dose reconstruction. The approach to dose 

reconstruction for thorium in the TBD is not well founded in the available data and not 

claimant favorable. NIOSH has stated that it has additional data that it will incorporate 

into a revision of the TBD. 

•	 The recycled uranium (RU) data are internally inconsistent and also inconsistent with 

some available DOE documentation. They are incomplete and do not appear to be 

claimant favorable for many workers and periods, though they are likely to be claimant 

favorable for many others. The problem in regard to adequacy of RU data is even more 

difficult for RU raffinate streams, in which the trace radionuclides, notably plutonium239, thorium-230, and neptunium-237, became concentrated. 

•	 The TBD does not address the extremely high uranium dust concentrations that were 

associated with certain jobs, locations, incidents, and time periods. The adequacy of 

uranium bioassay data in terms of the frequency of bioassay needs to be assessed in this 

context. 

•	 Workers who may have worked with raffinates may be missed by the protocol specified 

in Vol. 5 of the TBD. The guidelines for determining which workers were exposed to 

raffinate dusts are too restrictive and place far too great a reliance on completeness of 

records for job assignments, or in the alternative, place the burden of proof on the 

claimant. They have not been adequately justified by measurements and are not claimant 

favorable. There is no dose reconstruction protocol specified relative to the raffinate 
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streams in Plant 2/3; this may be especially important for employees exposed to raffinate 

streams from high-grade ore processing, including pitchblende processing. 

•	 Shallow external doses, including dose to the fingers and hands, appear to be 

underestimated. Correction factors to recorded dose for the differing locations of the 

organ and badge relative to the source need to be developed for certain jobs and practices. 

•	 The characterization of radon sources is not complete and occupational radon dose 

estimation is not claimant favorable. 

•	 There is documentation indicating that the source term for uranium used for occupational 

environmental dose has significant deficiencies and that a higher source term should be 

used. The main source of occupational environmental dose may be from diffuse uranium 

and thorium emissions in production areas; this has not been evaluated. 

1.2.2 List of Findings 

Finding 1: The list of facilities in which thorium-232 was processed, the time periods of 

thorium processing, and the thorium production data shown in the TBD have significant gaps. 

Entire periods of processing and plants in which the work was done have been missed. These 

gaps may affect the feasibility of dose reconstruction for workers for certain time periods and in 

certain plants. 

Finding 2: Air concentration data for thorium in the TBD are sparse and incomplete, though 

considerably more data are available on the NIOSH Site Research database. The TBD contains 

no thorium-232 bioassay or in-vivo data. 

Finding 3: Thorium intakes due to fugitive emissions and resuspension in production areas may 

have been significant for some locations and periods. The TBD does not address the issue of 

fugitive emissions in production areas. Furthermore, the TBD does not provide a method to 

estimate resuspension intakes in the pre-1986 period and for those workers without lapel air 

sampling in the post-1986 period. 

Finding 4: The guidance in the TBD regarding exposures from redrumming thorium is not well 

founded and is not claimant favorable. 

Finding 5: The TBD has not evaluated exposures due to thorium fires. The TBD has also not 

evaluated other thorium incidents or failures of industrial hygiene. 

Finding 6: The approach suggested for estimating thorium intakes does not reflect the history of 

production or the available thorium air concentration data. It is likely to result in significant 

underestimates of internal dose from thorium. 

Finding 7: The TBD does not specify a method for estimating doses in the raffinate streams, 

which are uranium-poor, from ore processing in Plant 2/3. These doses may be very difficult to 

calculate, especially for high-grade ores, notably pitchblende ore from Congo. 
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Finding 8: Workers who may have worked with raffinates may be missed by the protocol 

specified in Vol. 5 of the TBD. The guidelines for determining which workers were exposed to 

raffinate dusts are too restrictive and place far too great a reliance on completeness of records for 

job assignments, or in the alternative, place the burden of proof on the claimant. They have not 

been adequately justified by measurements and are not claimant favorable. 

Finding 9: The data on trace contaminants in RU in the Fernald TBD are incomplete and appear 

to be incorrect. Different official documents have very different values for various aspects of 

RU data, including production and contamination. The contradictions have not been sorted out 

in the TBD. 

Finding 10: The radionuclide list for RU in the TBD is incomplete. Furthermore, the 

concentrations of trace radionuclides in the raffinates, which are much higher than those in the 

feed material, are not adequately discussed. 

Finding 11: The suggested approach for RU dose estimation in the TBD is claimant favorable 

for many RU workers, but not claimant favorable for others and for some periods; it is not based 

on an evaluation of the available data. 

Finding 12: The TBD notes that uranium batches with enrichment greater than 2% were 

processed at Fernald. NIOSH’s assumption of 2% enriched uranium is claimant favorable most 

of the time, but not for periods and batches when uranium of higher enrichments was processed. 

Finding 13: Female employees were not monitored for long periods at Fernald, even though at 

least some of them were at some risk of internal intakes of radionuclides. 

Finding 14: The TBD does not address the extremely high uranium dust concentrations, which 

were present at Fernald under a variety of circumstances, and their effect on dose reconstruction. 

Particle size and solubility assumptions for workers who experienced chip fires should be 

examined. 

Finding 15: Ingestion doses are not considered in the TBD. 

Finding 16: Protocols for reconstructing shallow external dose during the operations at FEMP 

need to be further developed. 

Finding 17: Extremity doses appear to be underestimated. 

Finding 18: Beta dose to the rest of the body would also be underestimated, based on the TBD 

guidance. 

Finding 19: The TBD does not analyze the special problems associated with geometry of the 

source relative to the exposed organ and dosimeter in thorium handling and production. 

Finding 20: Correction factors used during an initial period of use of thermoluminescent 

dosimeters (TLDs) at Fernald are not scientifically appropriate. 
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Finding 21: The method for estimating external dose to unmonitored female employees is 

incomplete and its claimant favorability has not been appropriately demonstrated. 

Finding 22: The source term for atmospheric uranium emissions from Fernald is significantly 

underestimated. 

Finding 23: The TBD has not adequately considered various aspects of internal environmental 

dose, including the applicability of the Gaussian model, episodic releases, and particle size. 

Finding 24: Diffuse emissions of uranium and thorium may have produced significant internal 

exposures for some personnel 

Finding 25: NIOSH’s modeling of radon dose is not claimant favorable and does not take actual 

working conditions into account. 

Finding 26: NIOSH has not considered a major source of radon dose—the storage source of 

pitchblende ore onsite near Plant 1. 

Finding 27: The TBD does not consider outdoor diffuse emissions in production areas as a 

source of external environmental dose. 

Finding 28: External environmental dose for workers near the K-65 silos needs to be better 

evaluated. 

Finding 29: Occupational internal exposure to radon is estimated based on just two radon data 

points from 1953. This is an inadequate basis to reconstruct occupational radon dose. 

Finding 30: The possible use of photofluorography (PFG) at Fernald in the early years was 

ruled out in the TBD without adequate documentation. This is contrary to NIOSH general 

guidance and is not claimant favorable. 

Finding 31: The assumption that there was a 15% retake rate for x-rays is not adequately 

documented or analyzed. 

Finding 32: The assumption that there was collimation is not technically justifiable based on the 

evidence provided in the TBD and is not claimant favorable. 

Finding 33: NIOSH has prematurely concluded that lumbar spine x-rays for laborers and 

construction workers were not conditions of employment. Based on the evidence provided, this 

assumption is not sufficiently documented and is not claimant favorable. 

1.3 OPPORTUNITIES FOR IMPROVEMENT 

SC&A suggests that NIOSH evaluate the following suggestions for incorporation into the revised 

TBD: 
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(1) Various internal inconsistencies and problems of a factual nature in the TBD identified in 

this review should be corrected. 

(2)	 All aspects of the estimation of internal thorium-232 dose need to be reconsidered based 

on a more complete compilation and analysis of the data. Ingestion doses particularly 

need to be taken into account for thorium dose estimates that are developed only from air 

concentration data. A model for estimating thorium resuspension doses is also needed. 

(3)	 Clearer criteria for who worked with raffinate waste streams should be developed to 

ensure that internal dose estimates are scientifically defensible and claimant favorable. 

The radionuclide ratios to be used for dose reconstruction for raffinate workers also need 

amendment, including dropping the lead-210 term. 

(4)	 NIOSH should verify whether its use of ORAUT-OTIB-0002 results in a larger dose than 

intakes from the raffinate waste streams or K-65 waste handling. 

(5)	 NIOSH should undertake a more complete review of RU data and apply them in a 

manner that ensures that workers who handled the process streams with higher 

concentrations receive claimant-favorable treatment. Particular attention to the intakes 

associated with raffinate streams during RU processing is needed. 

(6)	 The use of uranium bioassay as the primary source of data for uranium internal dose 

reconstruction is appropriate; however, NIOSH should ensure that its assumptions about 

particle size during events like chip fires are claimant favorable. NIOSH should also 

check to see if bioassay frequency was sufficient to capture some very high episodic air 

concentrations, such as those arising from maintenance or repair work. More complete 

data are needed to determine which batches of uranium processed at Fernald had 

enrichments greater than 2%. 

(7)	 Specific guidance for internal and external dose reconstruction for female employees 

should be developed, especially since they were not monitored at all during 1951–1960 

and 1969–1978. 

(8)	 A claimant-favorable approach to estimating beta doses to the extremities and to the rest 

of the body needs to be developed. 

(9)	 An investigation into the external dose of record in employee files for the period between 

January 1983 and October 1985 is needed, due to inappropriate correction factors that 

were applied to TLD measurements. 

(10) A more complete and thorough approach to environmental dose estimation is needed, 

including consideration of source terms, episodic releases, diffuse emissions in 

production areas, and use of models suitable for considering exposures near buildings. 

(11) An approach to estimating radon dose that takes more complete account of working 

conditions and locations should be developed, including consideration of workers near 

Plant 1 and Plant 2/3, and near the K-65 silos. 

(12) NIOSH should attempt to better characterize occupational radon exposures to workers 

who handled K-65 waste. 
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(13) If further research that NIOSH is conducting into occupational medical dose does not 

lead to positive evidence that PFG was not used, dose reconstruction guidance for 

Fernald should specify an assumption of PFG use from 1951 to 1958. 

(14) The assumption that there was collimation in the medical x-ray units from inception of 

use should be discarded unless new evidence is developed in this regard. 

(15) 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. 
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2.0 SCOPE AND INTRODUCTION 

2.1 REVIEW SCOPE 

Under the Energy Employees Occupational Illness Compensation Program Act of 2000 

(EEOICPA) 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 Feed Materials Production Center (FMPC), whose name 

was changed during the decommissioning phase to the Fernald Environmental Management 

Project (FEMP), and which is commonly known as Fernald or the Fernald Plant: 

•	 ORAUT-TKBS-0017-1, Technical Basis Document for the Fernald Environmental 

Remediation Project – Introduction, Vol. 1, Rev. 00 (Fernald TBD, 2004a) 

•	 ORAUT-TKBS-0017-2, Technical Basis Document for the Fernald Environmental 

Remediation Project – Site Description, Vol. 2, Rev. 00 (Fernald TBD, 2004b) 

•	 ORAUT-TKBS-0017-3, Technical Basis Document for the Fernald Environmental 

Remediation Project – Occupational Medical Dose, Vol. 3, Rev. 00 (Fernald TBD, 

2004a) 

•	 ORAUT-TKBS-0017-4, Technical Basis Document for the Fernald Environmental 

Remediation Project – Occupational Environmental Dose, Vol. 4, Rev. 01 (Fernald TBD, 

2006) 

•	 ORAUT-TKBS-0017-5, Technical Basis Document for the Fernald Environmental 

Remediation Project – Occupational Internal Dose, Vol. 5, Rev. 00 (Fernald TBD, 

2004d) 

•	 ORAUT-TKBS-0017-6, Technical Basis Document for the Fernald Environmental 

Remediation Project – Occupational External Dosimetry, Vol. 6, Rev. 00 (Fernald TBD, 

2004e) 

These documents are referred to in this review as Fernald TBD Vols. 1 through 6. There were no 

technical information bulletins (TIBs) specific to Fernald that had been published as of the end 

of July 2006. SC&A also reviewed a variety of literature, including that on the NIOSH Site 

Research database, GAO report, historical documents (including those available from the worker 

and offsite litigation at Fernald), and Congressional Hearings. SC&A, in support of the 
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Advisory Board, has critically evaluated the Fernald 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 

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 SC&A 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 Fernald 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, the purpose of site profiles is to 

provide 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 (POC) 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 review of Fernald has some precedent in prior SC&A reviews of NIOSH TBDs, as well as 

the process of comment resolution regarding those TBDs initiated by the Advisory Board. This 

is especially true regarding certain aspects of Fernald dose reconstruction, such as that relating to 
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thorium exposures (Mallinckrodt and Y-12), K-65 silo materials (Mallinckrodt), recycled 

uranium (RU) (various TBDs), ingestion, resuspension, and clothing contamination. 

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 Fernald personnel and environmental 

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

interviews were conducted with current and former Fernald workers. 

All review comments apply to the versions of the Fernald TBD cited above, since they are the 

most recent published versions. 

In May 2006, 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 in 

August. They are reproduced in Attachment 2. A conference call was held with NIOSH and 

contractor personnel. 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. The site 

experts included current and former staff from radiation control, operations, environmental 

monitoring, maintenance, security, and other support organizations. Attachment 4 provides an 

integrated summary of the interviews conducted by SC&A. These interviews were conducted 

during the course of the Fernald Site Profile Review. 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 

Fernald 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. 

While none of the interviews were classified, they were submitted to the DOE along with the 

summary in Attachment 4 for declassification review as a precautionary measure. 

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 Methods 

(4) Site Profile Strengths 

(5) Findings 

(6) Observations 

(7) Overall Adequacy of the Site Profile as a Basis for Dose Reconstruction 
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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 Fernald 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. 
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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 Fernald Site Profile; however, 

items identified in this report may be applied to other facilities, especially facilities with similar 

source terms and exposure conditions. Similarly, we have drawn on prior SC&A reviews and 

scientific discussions with the Working Group of the Advisory Board and NIOSH and its 

contractors relating to similar issues at other sites. 

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 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 Fernald 

site and some of the records that were part of the Fernald Special Exposure Cohort (SEC) 

Petition. SC&A also reviewed some Fernald claimant files in order to examine how the data and 

the TBD were being applied in practice and coordinated parts of this review with Task 4 of this 

project, under which SC&A is auditing individual dose reconstructions. 

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 Fernald. 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. 
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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 Fernald TBD volumes 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. 

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 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 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 uncertainty for reasons of process 

efficiency, as long as this limited effort produces a POC of greater than or equal to 50%. 
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Category 2: A second category of dose reconstruction defined by Federal guidance 

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.] 

Fernald TBD Vol. 1, ORAUT-TKBS-0017-1, Technical Basis Document for the Fernald 

Environmental Management Project – 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 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 for identifying site-specific practices, parameter values, 
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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. 

Fernald TBD Vol. 2, ORAUT-TKBS-0017-2, Technical Basis Document for the Fernald 

Environmental Management Project – Site Description, is a very important document, because it 

provides a description of the facilities and processes, including historical information that serves 

as the underpinning for the specific dose estimation volumes of the Fernald TBD. It also 

provides air concentration and other data relating to the Fernald site. 

Fernald TBD Vol. 3, ORAUT-TKBS-0017-3, Technical Basis Document for the Fernald 

Environmental Management Project – Occupational Medical Dose, provides a set of procedures 

for reconstructing the radiation exposures of workers from medical radiographic procedures that 

were required of employees at the Fernald site. 

Fernald TBD Vol. 4, ORAUT-TKBS-0017-4, Technical Basis Document for the Fernald 

Environmental Management Project – Occupational Environmental Dose, provides background 

information and guidance to dose reconstructors for reconstructing the doses to workers who 

may have been exposed to routine and episodic airborne emissions from the facilities when they 

were outdoors at the site. It also includes an evaluation of dose from radon, emitted from the K65 silos, and its radioactive decay products. 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. 

Fernald TBD Vol. 5, ORAUT-TKBS-0017-5, Technical Basis Document for the Fernald 

Environmental Management Project – Occupational Internal Dose, 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. Some attention is also paid to intakes via 

wounds. 

Fernald TBD Vol. 6, ORAUT-TKBS-0017-6, Technical Basis Document for the Fernald 

Environmental Management Project – Occupational External Dose, 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 used for 

applying correction factors to the measured dose. 
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It is important to note that SC&A’s review of the Fernald 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. 
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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 Fernald TBD. These strengths are listed below. 

4.1 INTRODUCTION TO THE TBD 

Volume 1 of the TBD gives a very helpful overview of operations at Fernald without going into 

technical detail. 

4.2 SITE DESCRIPTION 

As a general point, the organization of the description on a plant-by-plant basis, and within that, 

by processes and activities, followed by radiation sources, is very helpful and takes the reader 

through site operations in a coherent manner. Furthermore, it is useful to group waste 

management facilities, activities, and processes, and discuss them after the presentation of 

operational aspects of the site. The summary of FEMP radioactive materials and characteristics 

is properly placed at the end of the document. 

4.3 AIR CONCENTRATIONS RELATING TO K-65 MATERIAL 

While the data for radioactive dust concentrations (non-radon) during the loading of the K-65 

Silo 1 are sparse, they have been used in a claimant-favorable manner in the suggested dose 

reconstruction procedure. However, there are other aspects of K-65 raffinate dose estimation 

procedures that are not claimant favorable (see Findings 7 and 8). 

4.4 NEUTRON DOSE ESTIMATION 

The TBD recommendations with respect to neutron dose reconstruction have been well 

documented, and make a number of claimant-favorable assumptions. The neutron-to-photon 

dose ratio and the neutron-spectrum assumptions are claimant favorable, and the summary of 

reasonable but claimant-favorable assumptions for missed neutron dose is also a positive part of 

the document. 

4.5 AP GEOMETRY 

The use of the AP geometry for all working conditions and radiation fields is claimant favorable 

and is a positive part of the document. 
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5.0 FINDINGS 

SC&A has developed a list of key issues regarding the Fernald 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 may be 

applicable to other Department of Energy (DOE) and Atomic Weapons Employer (AWE) sites, 

and should be considered in the preparation and revision of other site profiles. This would more 

likely be the case for sites where (1) uranium was processed into metal, (2) uranium ores were 

refined into U3O8 (black oxide), (3) residues from uranium ore processing were handled and 

stored, (4) thorium was processed in various chemical forms or as metal, and (5) scrap materials 

processing. 

NIOSH/ORAU are making or planning various revisions to the Fernald TBD in response to the 

questions that SC&A sent NIOSH (Attachment 1). (NIOSH/ORAU’s responses to those 

questions are in Attachment 2.) The revisions that NIOSH is planning to the TBDs were 

discussed during a conference call between NIOSH, ORAU, and SC&A on August 18, 2006 

(Attachment 3). The list below summarizes the action items that NIOSH/ORAU are pursuing. 

SC&A has nonetheless presented its review of these items, so that NIOSH may have the details 

of their review that SC&A has already completed. The list below and the review in this chapter 

may make the process of revising the TBD and addressing outstanding issues more efficient in 

terms of time and resources. 

NIOSH/ORAU are pursuing the following items as part of their revision of the Fernald TBD: 

(1) NIOSH/ORAU will create a flowsheet for the processing of high-grade ores at Fernald 

(residues were stored in Silo 2) and try to benchmark that with Mallinckrodt Chemical 

Works (MCW). 

(2) Volume 2 of the TBD will be made consistent with Vols. 4 and 5 in regard to in-plant 

thorium-232 concentrations. The suggestion in Vol. 2 that in-plant concentrations are 

quantitatively related to emissions will be removed. It will also make Vol. 2 and Vol. 5 

consistent by removing the implication in Vol. 2 that a decontamination factor for the use 

of respirators is to be used in dose reconstruction. No use of respirators will be assumed 

in dose reconstruction, as explained in Vol. 5 of the TBD. 

(3) NIOSH/ORAU will send staff to the Fernald records center, look at some of the archived 

records, including medical x-ray films, and try to resolve some outstanding questions, 

including whether PFG was used, whether the black line at the bottom of the films was 

due to collimation, and whether work-related lumbar spine x-rays were done. 

(4) NIOSH will clarify where it got its assumption about a 15% retake rate for x-rays. 

(5) NIOSH will review its use of the Boback et al. (1987) and Dolan and Hill (1988) source 

terms for releases of uranium to the atmosphere. NIOSH will also reassess thorium-232 

releases. As part of this, NIOSH/ORAU will also consider the reports of the Radiological 

Assessments Corporation (RAC) prepared for the Centers for Disease Control and 

Prevention (CDC) during the 1990s. 
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(6) NIOSH/ORAU are re-evaluating their approach to thorium-232 dose reconstruction and 

will post additional documents that they have found on thorium on the NIOSH Site 

Research database. 

(7) NIOSH/ORAU will review the issue of correction factors to film badge and TLD 

readings, including those discussed in Volume 4 of the Westinghouse 1986 transition 

report, to ensure that inappropriate correction factors were not used for doses that are in 

worker records. 

(8) NIOSH/ORAU will assess the issue of geometry of source relative to organ and film 

badges/TLDs and estimate correction factors as needed. In particular, a correction factor 

will be developed for workers who sat astride ingots to stamp identification numbers on 

them. 

A general comment should be made regarding the internal and external dose monitoring at 

Fernald, which will provide some perspective on the findings. Routine bioassay monitoring for 

uranium was done throughout the program for production workers. These data are available for 

individual dose reconstruction. Workers were issued film badges from the onset of production 

operations and these data should also be useful in dose reconstruction. Some issues relating to 

the adequacy or completeness of these data are explored in these findings, along with other 

issues. 

5.1 ISSUE 1: THORIUM-232 EXPOSURE 

5.1.1 Thorium Processing Facilities and Periods 

Finding 1: The list of facilities in which thorium-232 was processed, the time periods of 

thorium processing, and the thorium production data shown in the TBD have significant 

gaps. Entire periods of processing and plants in which the work was done have been 

missed. These gaps may affect the feasibility of dose reconstruction for workers during 

certain periods and in certain plants. 

The TBD considers thorium-232 work to have been done mainly in the Pilot Plant and Plant 9. It 

also acknowledges work in Plant 8 and, for a short period, of production in Plant 4. The TBD 

does not mention Plant 6 in connection with thorium production; however, the documentation 

clearly shows that thorium was processed in Plant 6 at least from 1960 to 1962. 

Table 1 shows Plant 6 thorium air dust data from documents that are on the NIOSH Site 

Research database Furthermore, it is clear that production continued into 1963. The dust survey 

report from which the data in Table 1 are derived was written in March 1963. Despite the 

extremely dusty conditions in some operations (notably raking cold residue into the furnace at 

1,260 Maximum Allowable Concentration (MAC)), production was continuing at the time the 

report was written. The report recommended that “this furnace should be shut down 

immediately after processing the thorium now on site. J. Carvitti estimates that this should be 

completed by approximately July 1, 1963” (Starkey 1963). 
 

 

 

 

 

 

 

 

 

 

 

 

 

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Table 1: Plant 6 Air Dust Data, 1960 to 1962 

Location Sample 

Year 

Type of 

Sample 

Air 

conc, 

xMAC 

Comments 

Raking excessive cold residue into furnace 1962 BZ 1,260 Recommended for shut down 

July 1, 1963 for clean up 

Unplugging furnace discharge line 1962 BZ 417 

Unplugging furnace discharge line 1961 BZ 4.0 Same location as 1962 

Unplugging furnace discharge line 1960 BZ 4.0 Same location as 1962 

Loading Th metal into 5-gal can from 55-gal 

drums 1962 BZ 69 

Raking drum residue into Rotex sifter 1962 BZ 27 

Raking drum residue into Rotex sifter 1961 BZ 31 Same location as 1962 

Raking drum residue into Rotex sifter 1960 BZ 33 Same location as 1962 

Changing drum at product canning station 1962 BZ 19 

Changing drum at product canning station 1961 BZ 4.0 Same location as 1962 

Changing drum at product canning station 1960 BZ 4.0 Same location as 1962 

Charging furnace with pieces of metal 

Charging furnace with pieces of metal 

Charging furnace with pieces of metal 

1962 

1961 

1960 

BZ 

BZ 

BZ 

7 

3.0 

3.0 

Same location as 1962 

Same location as 1962 

Source: Starkey 1963 

Note: 1 MAC = 70 dpm/m3
 

A Fernald history of thorium residue processing indicates that burning of residues began in 

Plant 6 in 1959, when a furnace there was modified to burn residues accumulated from metal 

production during 1955 and 1956 in Plant 9. There were 80 tons of residues (Mead 1972, p. 86). 

Hence, there is documentary evidence for thorium residue burning from sometime in 1959 until 

at least mid-1963. (It is unclear whether thorium operations took place in Plant 6 after that date.) 

A 1954 evaluation of dust levels at various plants involved in chemical and metallurgical work 

with thorium provided recommendations for the steps to be taken at Fernald in order to make 

Plant 6 “suitable for thorium rolling” (Klevin 1954, p. 19). 

Neither Table 5-13 nor Table 5-14 in Vol. 5 of the TBD, which show production data by plant, 

chemical form, and time period, have any thorium production listed for 1960, 1961, 1962, or 

1963. The Site Description (Vol. 2 of the TBD) also does not mention Plant 6 as a thorium 

production location. Finally, one of the main references that NOISH used in compiling the 

thorium production data (Dolan and Hill 1988) also does not list Plant 6 as a production location 

for thorium: 

Thorium was processed at the FMPC throughout much of the thirty-five year 

history of the site. The demand for various thorium materials fluctuated greatly 

and the FMPC developed or modified processes to meet these varying 

requirements. During different periods, thorium was processed through 

Plants 2/3, 4, 8, 9, and the Pilot Plant. [Dolan and Hill 1988, p. 57] 

Thorium tetrafluoride was produced in a “short” campaign in Plant 4, but production data are not 

available: 
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In 1954, Plant 4 was used for a short campaign to produce dry ThF4 from the 

ThO2 dried and calcined in Plant 9 in hydrofluorination Bank 7. The ThF4 was 

returned to Plant 9 and used to produce thorium metal. This was a shortduration process due to mechanical difficulties in Bank 7. Production quantities 

are not available for ThF4 production in Plant 4. [TBD, Vol. 2 p. 24] 

While the TBD does not provide a reference for these statements, it appears that they are based 

on Dolan and Hill (1988, p. 61). However, Dolan and Hill are not as definite that production did 

not occur at other times: 

Production quantities are not available for ThF4 in Plant 4. Because of the 

problems encountered, it is believed that this process was only operated for a 

short period and hence the potential for emissions was very slight. [Dolan and 

Hill 1988, p. 61] [Emphasis added.] 

Since thorium residues, including metal residues, were processed in a furnace in Plant 6 between 

1960 and 1963 (inclusive), the question arises as to where the thorium processing was done to 

produce the metal in this period. Neither the TBD nor Dolan and Hill provide any production 

data for these years. It is plausible that chemical processing of thorium, including production of 

thorium tetrafluoride and reduction of the tetrafluoride to metal, occurred at Fernald during 1960 

to 1963 (possibly only the first half of 1963). It may also have occurred in the late 1950s and in 

other periods. 

Dolan and Hill (1988) concluded that thorium production in the Pilot Plant started in 1964. 

Vol. 2 of the TBD indicates that thorium tetrafluoride was produced in the Pilot Plant and then 

reduced to metal in the 1969–1971 period. Reduction of ThF4 to metal occurred in Plant 9. 

Dolan and Hill (p. 59) also state that “[t]horium metal was produced in Plant 9 from 1954 

through 1955.” Machining was also done in Plant 9 during this period (p. 59). 

It is possible that these facilities were used in the 1960–1963 period for ThF4 production and 

reduction; however, this needs to be more carefully investigated. In that case, it is also possible 

that Plant 2/3 may have been used to produce the thorium nitrate feedstock that was the starting 

point of the ThF4 production process. 

SC&A has not located any positive documentation that Plant 5, where the UF4 reduction to metal 

was done, was also used for ThF4 reduction. However, a 1954 evaluation (Klevin 1954) of 

thorium health hazards recommends that consideration should be given to the use of the “‘F’ 

machine in charging thorium bombs since these have proved to be effective in controlling 

airborne contamination and are operationally satisfactory at both MCW and FMPC Plant 5” 

(p. 11). It appears that at least at the time of the evaluation (March 1954), such a machine was 

not available in Plant 9, where the ThF4 reduction was being carried out. Hence, it is possible 

that the charging of the bombs may have been done at Plant 5 for some time until a suitable 

machine was procured for Plant 9. It may also have been used in the later 1960–1963 period. 
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SC&A stresses that it is making the above statements about possible work in Plant 4 and Plant 5 

(or additional undocumented work in Plant 9 and/or the Pilot Plant) as pointers for research into 

thorium production history, rather than as conclusions. Thorium data are likely to be one of the 

most critical parts of dose reconstruction for Fernald claimants who worked there from 1954 

onwards. As NIOSH and ORAU acknowledged in the August 18, 2006, conference call, the 

TBD does not reflect a considerable amount of documentation that is available or becoming 

available (see Section 8.1.1). 

The TBD lists Plant 2/3 as a location for thorium processing: 

In 1968, Plant 2/3 was used to process thorium as a thorium production test for a 

short duration. Few details are available regarding this process. Thorium 

nitrate crystals were produced in a denitration pot in Plant 2/3. Interviews with 

long-time employees indicated that this was a short-term operation; probably one 

pot of crystals was produced. Other records discuss the production of thorium 

oxide in Plant 2/3 by a process of denitration, redigestion, and drying. [TBD, 

Vol. 2, p. 20] 

No plant-specific data enabling dose reconstruction are provided. Production data shown in 

Table 6 of Dolan and Hill do not contain any data for Plant 2/3 thorium production amounts or 

time periods (Dolan and Hill 1988, p. 20). Since Plant 2/3 was the refinery where uranium ores 

were processed, it may be presumed that thorium ores were also processed there. This has 

considerable significance for worker exposure. The TBD does mention the processing of 

thorium ores at Fernald, but lists them as being processed in the Pilot Plant as part of the thorium 

processing there between 1964 and 1980 (TBD, Vol. 2, p. 11); however, records show that 

thorium production at Fernald went back to 1954. This raises the question whether thorium 

processing took place in Plant 2/3 in connection with early thorium-related processes in Plant 9 

and Plant 4. The information in Dolan and Hill on thorium was partly based on interviews, but 

NIOSH was unable to provide any interview records to SC&A. 

According to the TBD, much of the thorium data was destroyed in the 1970s: 

Much of the thorium production data has been lost, and the plant and bioassay 

monitoring data recovered to date has been sparse. A comprehensive effort to 

reconstruct the effluent of uranium and thorium from the Fernald plants in 1988 

discovered that a large number of records and files were destroyed in the early 

1970s during declassification efforts (Dolan and Hill 1988). Reviews of AEC 

records in Oak Ridge and Atlanta failed to uncover additional details. [TBD, 

Vol. 5, p. 18] 

There are other problems with the production data as well. For instance, Vol. 2 of the TBD 

states that thoria gel production for 1964 and 1965 was estimated based on a linear extrapolation 

of the quantity produced in 1966 through 1970: 

Production records also indicate that 492 metric tons of thorium as thoria gel 

were produced from 1966 to 1970. Production for 1964 and 1965 was estimated 
 

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based on a linear extrapolation of the quantity produced in 1966 through 1970. 

The estimated total production from this process is 686 metric tons assuming 

linear production from 1964 to 1970. (TBD Vol. 2, p. 11). 

No justification for this assumption is provided in the TBD. Furthermore, the data shown in 

Table 5-13 of the TBD (Vol. 5, p. 20) show that NIOSH assumed that only thoria gel was 

produced in 1964 and 1965, even though there was other processing and at least one other 

chemical form (thorium oxalate) produced in the Pilot Plant in the 1966 to 1970 period. If the 

average of the total production in the Pilot Plant were extrapolated backwards, the estimated 

production of thorium in the Pilot Plant in 1964 and 1965 would be 238 metric tons in each year, 

or about 2.4 times the amount estimated by NIOSH (98 metric tons in each year). No 

explanation is provided for the more limited extrapolation. 

Furthermore, if thoria gel was produced in 1964 and 1965, one would expect purified thorium 

nitrate solution also to have been produced. However, the text only discusses production from 

1966 onward. Was there any such production in 1964 and 1965? In fact, though Table 5-14 

shows that thorium nitrate was produced in the Pilot Plant, it is not explicitly mentioned in 

Table 5-13 where production estimates are provided. In this same context, it is confusing that 

some items of production have quantitative estimates (but without references) in Vol. 2 of the 

TBD, but there is no counterpart tabulation in Volume 5 on internal dose reconstruction. For 

instance, thorium nitrate production is not shown in Table 5-13 of Volume 5; however, Volume 

2 gives a rather precise value of 790.4 metric tons for the 1966–1973 period for the Pilot Plant 

(p. 11). 

Finally, a 1988 thorium records search document (Bonfer 1988) also indicates that the TBD 

compilation of production at Fernald is incomplete. The starting date for thorium production of 

1954 appears to be correct according to Bonfer 1988, which provides a date of January 26, 1954, 

with metal production operations starting on February 15, 1954—all in Plant 9. Bonfer 1988 

also mentions “extraction studies” being started in the laboratory in April 1954. These studies 

continued well into 1955. Furthermore, while Tables 5-13 and 5-14 show Plant 9 production 

only in 1954 and 1955, there is clear evidence that Plant 9 production covered a longer time 

span. For instance, Bonfer states the following: 

The final Plant 9 process of manufacturing massive thorium metal continues into 

1956. [Bonfer 1988, p. 2] 

Similarly, while Tables 5-13 and 5-14 show Pilot Plant production only beginning in 1964, 

Bonfer 1988 states the following: 

A project was initiated during July 1956 in the Pilot Plant to demonstrate the 

sylvania reduction process for calcium reduction of thorium oxide to thorium 

metal powder. [Bonfer 1988, p. 2] 

Attachment III in Bonfer 1988 is a catalog of orders for a variety of forms of thorium. It 

includes orders that were filled in 1957, 1958, and 1959—years that are not discussed for 

thorium production in the TBD. In this context, it is noteworthy that while the TBD does not 
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mention thorium metal production in Plant 9 in 1956, the history of residue recovery does. The 

quantity of production must have been significant, because the residues from 1955 and 1956 

amounted to 80 tons (Mead 1972, p. 86). Finally, Attachment II in Bonfer (1988) also shows 

three orders in 1985, but it is not clear whether these orders were filled with material that had 

already been produced prior to that time or whether there was post-1979 production at Fernald. 

The TBD does not discuss these orders or cite Bonfer (1988). 

In conclusion, it is very likely that production estimates in the TBD are significant 

underestimates. It is clear that Tables 5-13 and 5-14 (TBD, Vol. 5, p. 20) do not capture a large 

amount of the processing that was done, even from readily available documentation. The 

locations and time periods of processing are also significantly incomplete. A thorough revision 

of the TBD is necessary to establish when the workers were at risk of exposure due to 

production, and in which plants they were at risk. 

During the conference call of August 18, 2006, NOISH stated that it was in the process of 

recovering considerable additional thorium data (see Attachment 3); however, that data was not 

available in time for this review. SC&A did not come across information on the extent and 

nature of the additional data and documents, and therefore cannot comment on whether they 

would be adequate to plug the large gaps in the data and the uncertainties that have arisen as a 

result of the destruction of records. The evidence discussed above indicates that a large number 

of workers were exposed to thorium at various times during the 1954 to 1980 period as a direct 

result of production work. This includes Plant 2/3, Plant 4, Plant 6, Plant 8, Plant 9, the Pilot 

Plant, and the laboratory. 

In addition, the residue recovery history notes that the 80 tons of residues discussed above 

(“turnings, grinder sludge, sawdust, and miscellaneous solids”) were stored on pads at Plant 9 

and Plant 1 (Mead 1972, p. 86). Fires occurred on these pads during the periods the residues 

were stored there (see Finding 4). The TBD notes that Canadian ores containing thorium were 

received at Fernald beginning in 1956 and then in large amounts by June 1957 in the context of 

discussing Plant 1 (TBD, Vol. 2, p. 15), yet Plant 1 is not discussed in terms of thorium 

exposure. Finally, as noted above, it is possible that some ThF4 reduction occurred in Plant 5, 

but SC&A has not found any direct evidence of this. 

5.1.2 Thorium Air Concentration Data 

Finding 2: Air concentration data for thorium in the TBD are sparse and incomplete, 

though considerably more data are available on the NIOSH Site Research database. The 

TBD contains no thorium-232 bioassay or in-vivo data. 

According to the TBD, there were some in-vivo thorium data and one file with thorium urine 

data (beta count): 

The only discovered record of thorium exposure has been in vivo lung count data 

sheets in a few claimant records and a single claimant record which indicates 

thorium urine results, counted for beta and at essentially no detectable results, 

from before 1986. [TBD Vol. 5, p. 22] 
 

 

 

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Furthermore, on the same page, it is stated that there is some evidence of urinalyses for thorium 

in claimant files as early as 1955. This suggests more than a single claimant record, but these 

data are not presented in the TBD. The reason cited is as follows: 

The thorium results are questionable because of the lack of information for 

readily interpreting them (e.g., there is no information regarding the in vitro 

separation method or counting procedure/equipment, nor is there information 

regarding the assumptions made to derive the in vivo results). [TBD, Vol. 5, 

p. 22] 

However, the analytical techniques from the period of measurements are surely known. It may 

therefore be possible to interpret these data. Setting them aside without further analysis in favor 

of the intake estimation procedure chosen (see below) appears to be questionable.1 

SC&A acknowledges the difficulty in interpreting in-vitro and in-vivo bioassay data in terms of 

thorium intake and dose. To correctly interpret in-vivo monitoring data, we need to make 

assumptions on the equilibrium between thorium and thorium daughters, and on the absorption 

rates from lung to blood of the daughters in relation to Th-232. If monitoring were done 

measuring Pb-212 or Tl-204, which probably was the case in the 1960s and 1970s, the 

interpretation of results will require assumptions about Rn-220. Thus, it is not simple. 

Urinalysis results are not simple to interpret, either. The limits of detection until recently were 

so high that only very high exposures would be detected. Even today, thorium bioassay is very 

difficult to interpret, because of influence from the diet and very low excretion rate in urine. 

Given that the use of air sampling data can also be problematic,2 all available data should be 

analyzed together to have a better estimate of the worker’s exposure. 

The TBD states that thorium workers were monitored by lapel sampling of the breathing zone 

after 1986; however, it does not provide any of this post-1986 thorium sampling data. There is 

no analysis in the TBD of the completeness in regard to coverage of (1) workers who worked in 

maintenance, surveillance, repackaging and other post-production operations involving 

thorium-232 or during decommissioning of the thorium storage areas, and (2) workers that may 

have been affected by resuspension of thorium dust. 

The TBD contains some thorium air concentration data, but these are sparse and do not reflect 

the extent of data available regarding the plants for which data exist on the NIOSH Site Research 

database or the time periods for which data exist. For instance, the air concentration data for 

Plant 6 for the 1960–1962 period are not mentioned in the TBD. Table 2-1a (TBD Vol. 2, p. 12) 

shows very limited air concentrations for a single year (1968) for the Pilot Plant for just a few 

operations. The air concentrations range from about 0.3 MAC to about 5.7 MAC. Similar data 

are presented for uranium for the same year in the same table. 

1

 As noted above, NIOSH/ORAU have found a large amount of thorium-232-related data. SC&A’s 

comments here apply to the TBD in its state at the end of August 2006 and the documents available until that time. 2

 According to ICRP 2002, “the use of static [air] samplers does not ensure a representative measurement 

of exposure of the worker, especially in workplaces where the aerosol release points are discrete and distributed.” 

ICRP 2002, Annex B, Section B.5, p. 150. Even personal air samplers may also give misleading and inconsistent 

results in case of high specific activity radionuclides due to the low volume of air that is sampled (ICRP 2002, 

Annex B, Section B.6). 
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These data in Table 2-1a are used to estimate uranium intakes for 1968 and for other years by 

assuming that intakes were proportional to production (Table 2-1b). The uranium intakes in turn 

are used to estimate thorium intakes by multiplying the uranium intakes by the ratio of estimated 

air emissions of thorium to uranium (Table 2-1c, TBD Vol. 2, p. 14). 

This thorium intake estimation procedure contradicts the procedure in the internal dose volume 

of the TBD (discussed below). Moreover, it contains several layers of scientifically dubious or 

incorrect assumptions. For instance, intakes inside a plant are not necessarily related to air 

emissions. In fact, if ventilation is poor, low stack emissions may correspond to high intakes, 

making for an anti-correlation of intakes with air emissions. Furthermore, the air uranium and 

thorium emission estimates themselves are suspect (see below). Finally, individual worker 

intakes cannot be assumed to be proportional to production. They cannot be assumed to be 

proportional to capacity utilization, unless it can be shown that the machines were idle for part of 

the day (or other time period). Dust levels depend on working conditions. Small amounts of 

production can still lead to very high individual exposures. Overall production or capacity 

utilization is arguably related to population exposure, but other conditions, including ventilation 

and industrial hygiene measures, must be assumed to be the same even in that case. The intake 

estimation procedures in Tables 2-1b and Table 2-1c should be deleted from the TBD. 

Available evidence indicates that Fernald had significant levels of thorium air contamination 

from the start of thorium operations in 1954 to the end in 1979. Plant 6 air concentrations were 

especially high, up to and including 1962. Since changes were not made until July 1963 at the 

earliest (Starkey 1963), the high air dust problems likely continued at least until then in Plant 6. 

All available data from Fernald indicates that the air concentrations of thorium were very high in 

the early period, defined here as 1954 through at least 1962. 

Table 2 shows early air concentration data in reverse chronological order. 

Data that appear to relate to Plant 9 for 1955 indicate that several workers experienced average 

air concentrations of about 100 MAC, with the most exposed workers experiencing an average of 

several times that. Data for the following year for the same plant indicate a decline to between 

1 MAC and 71 MAC. 

Data from Plant 6 from the early 1960s show very high air concentrations from a few times 

MAC to 1,260 MAC, with a possibly rising trend of air contamination in 1962 compared with 

the previous years. Just 1 hour of exposure in a year to the operation with the highest air 

concentration would exceed the annual exposure of 1,050 MAC-hours recommended in the TBD 

(Vol. 5). 
 

 

 

 

 

 

 

 

 

 

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Table 2: Thorium Air Concentration Data: Fernald, 1950s and Early 1960s 

Operation Plant Year Type of air 

sample 

Air conc. 

xMAC 

Raking excessive cold residue into furnace 6 1962 BZ 1260 

Unplugging furnace discharge line 6 1962 BZ 417 

Unplugging furnace discharge line 6 1961 BZ 4.0 

Unplugging furnace discharge line 6 1960 BZ 4.0 

Loading Th metal into 5-gal can from 55-gal drums 6 1962 BZ 69 

Raking drum residue into Rotex sifter 6 1962 BZ 27 

Raking drum residue into Rotex sifter 6 1961 BZ 31 

Raking drum residue into Rotex sifter 6 1960 BZ 33 

Changing drum at product canning station 6 1962 BZ 19 

Changing drum at product canning station 6 1961 BZ 4.0 

Changing drum at product canning station 6 1960 BZ 4.0 

Charging furnace with pieces of metal 6 1962 BZ 7 

Charging furnace with pieces of metal 6 1961 BZ 3.0 

Charging furnace with pieces of metal 6 1960 BZ 3.0 

Thorium production various steps (Note 2) 9? 1955 ? 106 

Thorium production various steps (Note 2) 9? 1955 ? 353 

Thorium production various steps (Note 2) 9? 1955 ? 3,531 

Thorium production various steps 9? 1956? ? 1 

Thorium production various steps 9? 1956? ? 4 

Thorium production various steps 9? 1956? ? 71 

Thorium production (various steps?) 9? 1955 ? 500 

Thorium production (various steps?) 9? 1955 ? 600 

Cutting thorium derbies by hacksaw 9 1954 ? 36 

Sources: Starkey 1963; Harris 1956; and Karl [Illegible] 1955. 

Note 1: BZ = breathing zone; GA = general air 

Note 2: 106 MAC was the average for several workers; 353 MAC was the highest average; 3,531 MAC was the 

highest measurement. 

These data indicate the following: 

•	 Thorium dust levels were high and often very high during the 1950s and early 1960s. 

•	 Dust levels did not diminish with time in this period. In fact, there are instances where 

dust levels increased. 

The documents from which these data are drawn also show that production continued despite 

measurements of dust levels far in excess of the maximum allowable air concentration. We have 

already cited the example of production in Plant 6, which was allowed to continue during the 

first half of the year (at least), despite measurements in December 1962 of dust levels between 4 

and 1,260 MAC in various operations. In regard to the latter, the March 1963 memorandum 

states the following: 

Although the Thorium Furnace and Rotex sifter have ventilation, it is completely 

inadequate....The rabbeling arms in the top hearths of the furnace have been 
 

 

 

 

 

 

 

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removed, thus the excessive cold residue on the edge of the hearths is raked into 

the furnace by hand (this operation is 1260 x MAC). 

As was discussed in a meeting in your office this morning, this furnace should be 

shut down immediately after processing the thorium now on site. J. Carvitti 

estimates this should be completed by approximately July 1, 1963. [Starkey 1963] 

As another example, a telegram in December 1955 noted dust levels of 500 to 600 MAC, but 

suggested that thorium oxide production should “continue at three four zero zero [3,400] pounds 

per day” during that month. Then a shutdown of six weeks for improvement of conditions was 

proposed, after which production was to increase to 4,000 pounds per day (Karl [Illegible] 1955). 

Table 3 shows some later air concentration data for thorium. 

Table 3: Thorium Dust Concentrations: 1966 and 1977 

Work Location Plant Date Type of 

sample 

Air 

Conc. x 

MAC 

Pilot Plant data sheets (Note 1) Pilot Plant 1977 0.7 

Pilot Plant data sheets (Note 1) Pilot Plant 1977 5.0 

Dumping ThF4 into reverter dumping station 8 1966 BZ 29 

Scooping recycle ThO2 into reverter dumping station 8 1966 BZ 48 

Changing drums at reverter drumming station 8 1966 BZ 21 

Th reverter drum dumping station area 8 1966 GA 2.7 

Th reverter drumming station areas 8 1966 GA 1.9 

Th reverter level 8 1966 GA 1.8 

Source: Fernald Thorium datasheets from the NIOSH Site Research Database for 1977 data and Ross 1966. 

Note 1: 0.7 MAC is the empirical lognormal mean calculated from datasheets and 5.0 MAC is the 95th percentile 

value for the same data set. 

While the highest levels of dust in the set of samples shown in Table 3 are much lower than that 

in the earlier period (Table 2), the later levels are often above the allowable limit in 1966. A 

more extensive set of samples for the Pilot Plant indicate a mean dust level of about 0.7 MAC for 

1977 and a 95th percentile value of about 5 MAC (based on an empirical lognormal distribution). 

This is still rather high. We note here that the samples for 1968 for the Pilot Plant cited by 

NIOSH in Table 2-1a (discussed above) are between 0.3 MAC and 5.7 MAC. While these data 

indicate that the Pilot Plant thorium air dust levels may have been about the same for an 

extended period, such a conclusion cannot be reliably made because the data available are far too 

sparse and, in any case, are only for one of the plants where thorium was processed. 

Specifically, data from Plant 8 for 1966 show much higher concentrations than those cited by 

NIOSH for the Pilot Plant in 1968. Breathing zone concentrations were 21 to 48 MAC; even the 

general air in the area was 1.8 MAC. This indicates that uranium workers who were present in 

the Plant may have been exposed to significant amounts of thorium. 

SC&A has not located any air concentration data for Plant 4 that are labeled as such, even for 

1954, when some ThF4 production was done there. However, there are 1954 data for metal 

working—production of ingots at Fernald. The dust conditions in thorium metal working at 
 

 

 

 

 

 

 

 

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Fernald in that year were compared unfavorably in a general way to those at Ames. It is unclear 

if the Fernald dust data represent Plant 4 or Plant 9. Table 4 shows the Fernald and Ames data. 

Table 4: Thorium Dust Levels for Certain Operations: Fernald and Ames 

FMPC Year MAC 

Charging crucible, top furnace 1954 7.6 

Disassembly Th ingot 1954 4.9 

Placing top and bottom crucibles in mold section 1954 7.6 

General air at face of furnace while operator works 1954 0.7 

Operator inside furnace cleaning 1954 3.8 

Maintenance man loosens material in broken crucible (outside) 1954 156 

Same operation as above except with vent hood 1954 5.0 

Ames 

Insertion of dezinced billets into crucible 1952 6.6 

Removing graphite pots containing dezinced billets 1952 3.1 

Cleaning furnace parts brick insulation 1952 3.6 

Source: Klevin 1954, p. 13 

1 MAC = 70 dpm/m3 

While the operations shown were not the same, the evaluation made an unfavorable comparison 

of Fernald thorium dust with that at Ames: 

It should be understood that at Ames, ventilation was effectively employed to 

control these operations which at FMPC showed high dust dispersion. 

[Klevin 1954, p. 13] 

External dose data for the same operations at Fernald were also considerably higher, with jobrelated gamma dose rates being about 2 to 20 times higher [1 to 10.5 mr/hour at Ames and, 20 to 

24 mr/hour at Fernald]. The data are shown in Table 5. 

The higher external dose levels at Fernald were explained as follows: 

Note: FMPC did not use derbies but old Th metal scrap, therefore higher 

intensities encountered. [Klevin 1954, p. 14, underlining in the original.] 

Dust numbers from a 1952 Ames survey, as well as the external dose numbers, indicate that the 

Ames data are from March 1952 (Klevin 1952). That survey showed job-related daily weighted 

averages (DWAs) to range from very low (near zero) to over 44 MAC. The average DWA was 

about 7.6 MAC (530 dpm/m3

) for all thorium workers. 
 

 

 

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Table 5: External Dose Rates and Surface Contamination, Thorium Metal Casting: 

Ames vs. Fernald 

Alpha Gamma, Ames d/min/100 Beta, mrep/hr. 2 mr/hr.

cm

Average dezinced billet 

Top No data Off scale 10.5 

Bottom No data 3.5 9.5 

Middle No data 2.5 5.0 

Average cast billet 

Top No data 6.0 7.0 

Bottom No data 1.0 5 

Middle No data 1.0 4 

Average cast billet (20 hours old) 

Top No data 1.0 3.5 

Bottom No data 4.0 4.0 

Middle No data 3.0 1.0 

FMPC [Fernald] 

New billet freshly assembled from mold 

Top 1,000,000 12 24 

Bottom 106 10 20 

Middle 106 13 24 

Source: Klevin 1954, p. 14. 

As SC&A has pointed out before (Mallinckrodt reviews), the use of DWAs is not a claimantfavorable approach, especially as each operation has very few measurements associated with it 

(typically 1 to 3). They may be used for minimum dose estimation purposes, however. The 

higher thorium dust levels at Fernald compared to Ames, at least for some operations indicated 

by the above data, need to be taken into account in evaluating the adequacy of the data, given 

that both Ames and Fernald data are limited, and in selecting the values for thorium intake 

estimation. 

Klevin (1954) also provides data from other sites, including Lindsay, where thorium ore was 

processed, and for Simonds Saw and Steel, where thorium metal was rolled. Those data are 

shown in Table 6. 

It is clear from the above data that thorium production at all stages involved very high air dust 

levels at several plants. Even on a daily weighted average, air dust levels were many times the 

MAC. General air concentrations also exceeded MAC. At Fernald, very high dust levels 

continued well into the 1960s. Finally, data for the 1970s appear to be very sparse. It is 

interesting to note that even some wet area dust levels were found in the surveys to be above the 

MAC of 70 dpm/m3 . This is an indication that all thorium production operations should be 

considered high dust operations, unless reliable measurements are available to the contrary. 

Furthermore, in view of the high dust levels, areas in the proximity of production operations 

would also be likely to experience considerable thorium dust. 
 

 

 

 

 

 

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Table 6: Lindsay Light and Chemical Company and Simonds Saw
 

Thorium Air Dust Data 

Lindsay data MAC 

Charging and milling ore 8.0 

Rotary dryer operation 12 

Pot area (loading ore into sulfuric acid) 114 

Pot area (loading ore into sulfuric acid) 44 

Pot area (loading ore into sulfuric acid) 186 

Pot area (loading ore into sulfuric acid) 29 

Average for pot area (loading ore into sulfuric acid) 93 

Simonds data (1952?) 

Rolling Th daily weighted average 15 

Average General air during rolling 12 

Passing billets through rolls (roughing average) 67 

Passing billets through rolls (finishing average) 193 

Source: Klevin, 1954. 

It is important to note in this context that even 1 MAC exposure to thorium for certain organs 

yields a committed dose much higher than exposure to uranium, the main material processed and 

produced at Fernald for certain organs. (At the time, 1 MAC for thorium and uranium was 

defined as being the same number—70 dpm/m3 until 1970 and 100 dpm/m3 thereafter.) SC&A 

has pointed out the critical importance of this fact for dose reconstruction in other reports (see 

SC&A 2006, for instance). We reproduce Table 4 from SC&A 2006 for convenience (Table 7). 

Table 7: 50-Year Organ Dose Conversion Factors for U-234 and Th-232 – Inhalation 

(in sieverts per becquerel and ratios) 

Organ U-234 Type 

M, Sv/Bq 

U-234 Type 

S, Sv/Bq 

Th-232 Type 

S, Sv/Bq 

Ratio Th S/U 

M 

Ratio Th S/ U 

S 

Bone Surface 3.90E-06 5.03E-07 2.86E-04 7.33E+01 5.69E+02 

Breast 1.37E-07 1.63E-08 8.29E-07 6.05E+00 5.09E+01 

Liver 5.34E-07 6.93E-08 5.05E-06 9.46E+00 7.29E+01 

Red Marrow 4.03E-07 5.21E-08 1.00E-05 2.48E+01 1.92E+02 

Testes 1.37E-07 1.63E-08 2.62E-06 1.91E+01 1.61E+02 

Source: Federal Guidance Report 13, U.S. EPA, published on CD in 2002. 

Reproduction of Table 4, SC&A 2006. 

Note: DCFs are based on AMAD = 1 μm
 

Table 7 shows that a 1-MAC level of air contamination with Type S thorium-232 is equivalent to 

569 MAC of Type S uranium-234 for bone surface dose. Thus even ~0.1% Th-232 dust in the 

air (in terms of dpm/m3

) mixed in with uranium can make a significant contribution to bone 

surface dose. The dose conversion factors (DCFs) show that a few tenths of 1% can make a 

significant contribution to dose to the testes and red bone marrow. When assessed against these 

facts, the TBD is particularly deficient in regard to its attention to thorium air concentration data. 

As noted, NIOSH has stated that it is revising the TBD and incorporating more thorium data. 
 

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5.1.3 Thorium Fugitive Emissions 

Finding 3: Thorium intakes due to fugitive emissions and resuspension in production areas 

may have been significant in some locations and during some periods. The TBD does not 

address the issue of fugitive emissions in production areas. Furthermore, the TBD does not 

provide a method to estimate resuspension intakes in the pre-1986 period and for those 

without lapel air sampling in the post-1986 period. 

There is clear evidence of significant problems with fugitive emissions of thorium from 

production areas. These problems were not confined to early production. A 1970 memorandum 

on “Thorium Metal Production Housekeeping” is worth quoting at length in this regard: 

1.	 Probably the worst housekeeping problem in the facility is the Ball Mill. 

This equipment leaks excessively at practically every joint. All horizontal 

surfaces have a thick covering of dust. In operation, this dust becomes 

airborne and adds to the dust coming from the leaks. Since the ventilation 

is inadequate and there is no proper enclosure, a bucket was placed under 

the largest leak to help contain the spilled dust. This is not adequate. It is 

recommended that Engineering Division be requested to inspect the Ball 

Mill and associated equipment and recommend methods of improving both 

the dust problem and the housekeeping problem. 

2.	 During the operation of removing the calcined ThF4 and CaF2 from the 

retorts, the stack of trays is left standing on a skid near the south annex 

door. The door is left open to aid in cooling the trays. The wind coming 

through the door blows the loose powder from the trays and spreads it 

generously through the annex. Removing the trays from the support 

requires heavy effort and this dislodges more powder to be spread by the 

wind. It is recommended that this stack of trays be put inside the 

enclosure used for grinding, weighing, and blending their contents. 

[Ross 1970] 

It is unclear how long the problem of high fugitive dust existed prior to the 1970 memorandum, 

or for how long afterwards it persisted, but the document indicates that the levels of thorium dust 

were high both indoors and outdoors, and that industrial hygiene measures were poor. 

Moreover, the same memorandum makes it clear that significant residual contamination from the 

poorly controlled processes was present in many locations. They included the following: 

...the drying oven area, the bottom of the blending enclosure, the saws and the 

saw area, the entrance to the furnace room when used to remove dezinced derbies 

from their holders, the top deck of the furnace room, the ThF4 enclosure and the 

area surrounding it, and others. [Ross 1970] 

These circumstances indicate that both thorium production workers as well as those who did not 

directly work with thorium may have experienced significant thorium intakes due to faulty 

equipment, lack of adequate ventilation, and poor location of the equipment. Maintenance 
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workers who repaired the equipment may also have had large exposures due to resuspension of 

dust from the heavily contaminated surfaces. In view of the high DCFs of thorium relative to 

uranium for several organs, it is essential that dose reconstructors have explicit guidance on how 

these doses are to be estimated. 

Resuspension of thorium would also be an issue in the post-1986 period. The TBD does not 

document the protocols for Th-232 lapel sampling in this period. Given the conditions described 

above, the exposure potential for those who were not provided with such monitoring should be 

evaluated. The resuspension model suggested by SC&A as part of the evaluation of Bethlehem 

Steel might be considered in this context (SC&A 2005e). 

5.1.4 Exposures from Thorium Redrumming 

Finding 4: The guidance in the TBD regarding exposures from redrumming thorium is not 

well founded and is not claimant favorable. 

There were extensive thorium redrumming, packaging, and shipping operations in the 1980– 

1986 period. Such operations were also carried out during the period of thorium processing. For 

instance, a 1965 “Request for Engineering Services” began as follows: 

The thorium residue drums are disintegrating. Mr. Costa started redrumming 

these residues but was stopped by the IH&R Department due to high dust levels of 

contamination arising from dust generated by the redrumming operation. Prior 

to the IH&R shutdown of the redrumming operation, the sump cake had been 

redrummed in 900 drums and 100 drums of floor sweepings had been redrummed. 

...About 30% of the drums are so corroded that they cannot be lifted off their 

pallets without falling apart. This is the fourth time this material has been 

redrummed. There are approximately 2000 drums of this material. [DeFazio 

1965, emphasis added] 

The inference from the engineering request for ventilation system design is that the prior 

redrumming operations were carried out at least three times without such ventilation and that half 

the job in question (redrumming of 1,000 out of 2,000 drums) was also similarly carried out 

without ventilation. SC&A has not found air dust data relating to the redrumming operations 

referred to in DeFazio 1965. 

The TBD has only a brief discussion of doses arising from thorium storage operations 

(Section 2.3.2.1, TBD Vol. 2, pp. 50–51). This section does not discuss redrumming operations 

in the pre-1990 period at all. It considers corrosion only as one of four possible “Events” that 

could lead to airborne thorium contamination (“Fork impact,” “Fork drop,” “Physical 

degradation,” and “Miscellaneous”). Only 0.69 grams of thorium are assumed to be released 

during an event involving “Physical degradation,” and only 42 such events are assumed to take 

place each year (Table 2-22, p. 51, TBD, Vol. 2). The number of drum puncture events is very 

small compared to the 30% rate of greatly degraded drums in the 1965 assessment quoted above. 
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It is possible that many of them were included in the “miscellaneous” events category. However, 

in that case, the estimate of the amount released is even smaller—0.162 grams per event. 

NIOSH’s thorium intake estimates are based on estimated “dispersible thorium” per drum and a 

fraction of the dispersible thorium that would become airborne. Dispersible thorium per drum 

was estimated at between 683 grams and 79.1 kilograms (TBD Vol. 2, Table 2-21, p. 51). No 

references were provided for any of the data and no analysis was provided for the estimates of 

fractional airborne thorium that was applied to each event. No references were provided about 

event frequency. The context of the estimates indicates that they apply to the period of 

decontamination in the 1990s: 

During the 1990s, drums of thorium stored in various plant locations, 

including those in Building 65 and 67, were overpacked and transferred to 

Buildings 64 and 78 for interim storage and eventual offsite shipment. 

Structurally unsound drums were placed inside larger containers by overpacking. 

The overpacked and structurally sound drums were transferred to Buildings 64 

and 78 and subsequently placed in strong tight containers (STCs) suitable for 

offsite shipment. [TBD, Vol. 2, p. 50] 

Given that the TBD states that workers wore lapel samplers in the post-1986 period and that this 

would be the basis for thorium intake, it is unclear why Tables 2-21 and 2-22 were included at 

all, since they seem to apply to the 1990s. They do not apply to the earlier period of 

redrumming, when the rate of totally deteriorated drums was estimated at 30%. Moreover, the 

estimated dust concentration is only 1.97 10-5 g/m3

 (TBD Vol. 2, p. 51), which is only about 

0.07 MAC of Th-232 or 0.14 MAC when Th-228 is also taken into account. This is very likely 

to be far lower than the air concentrations in the redrumming of thorium in the 1960s and in 

other periods. This conclusion is based on the record that thorium and uranium were treated 

more or less on a par in those periods, with the same maximum allowable concentration, and a 

small fraction of 1 MAC would have been regarded as satisfactory. It is unlikely that an 

Engineering Request, such as the one from 1965 quoted above, would have been made if an 

operation were at 0.14 MAC. The very low estimate of airborne thorium appears to be in 

conflict with the evidence from the redrumming operation. It is unlikely to be correct for the 

period of production; it should also be re-evaluated for badly deteriorated drums even for the 

1990s, using lapel-sampling data that should be available. 

A 1968 memorandum identified drumming and dumping as the being responsible for the “most” 

serious air dust problems: 

As you well know, most of our air dust at FMPC over the years have resulted 

from drumming and dumping dry materials. Any time that we can eliminate 

either of these operations our air dust problems become greatly reduced. 

[Starkey 1968] 

The guidance for thorium exposure during redrumming needs to be re-evaluated and a new 

model developed. 
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5.1.5 Exposures due to Thorium Fires 

Finding 5: The TBD has not evaluated exposures due to thorium fires. The TBD has also 

not evaluated other thorium incidents or failures of industrial hygiene. 

There were a number of thorium fires in the 1950s at Fernald, including prolonged ones. A 

number of problems resulted from these fires. A proposed 1959 project to address the problem 

stated the following: 

During the past four years there have been 30 known fires with these materials 

[thorium residues], some of which burned for several days. Clean up after these 

fires is a difficult job. In one case, the fire burned through a concrete storage 

pad. Storage of the drums on soil resulted in a worse situation, when a fire 

contaminated a considerable area, and much stone and dirt had to be removed. 

As long as these residues are in the unoxidized state, the hazard and expensive 

housekeeping problems will exist. Corrosion from prolonged storage of the 

drums has resulted in oil leaks, and redrumming and clean up problems. 

Attempts to redrum these materials have resulted in violent reactions exposing 

personnel to possible serious injury. [NLO 1959, pp. 1–2] 

The TBD does not contain any discussion of these fires and related thorium incidents. The 

assessment quoted above states that there were “violent reactions,” but provides no dosimetric 

information. The modest discussion of redrumming in the TBD gives no hint of these serious 

problems in the production era, and how NIOSH proposes to reconstruct doses due to these 

incidents and to the various types of clean-up operations that followed. 

5.1.6 TBD Procedure for Estimating Thorium Intakes 

Finding 6: The approach suggested for estimating thorium intakes does not reflect the 

history of production or the available thorium air concentration data. It is likely to result 

in significant underestimates of internal dose from thorium. 

The TBD has the following formula for annual thorium exposure (Vol. 5, p. 23): 

• 100 hours of work at 10 MAC 

• 500 hours of work at 0.1 MAC 

This amounts to an annual intake corresponding to 1,050-MAC hours. The basis for this 

approach is described as follows in the TBD: 

In vivo counting was performed on the workers in the more likely exposed groups 

at least once each year. There is some evidence of urine analyses for thorium in 

claimant files as early as 1955, but to date no information has been found 

regarding how to interpret it. Although urinalysis can offer some information 

regarding thorium intake, it is not the preferred bioassay technique, since the 

material is predominantly insoluble. Fecal sampling and in vivo analyses are the 
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preferred default. This is a difficult default to derive with any degree of technical 

basis because: 

1- There was primarily gross alpha and some gross beta air monitoring during 

thorium operations for the purpose of controlling worker exposures to below 

MAC levels. A few in vitro analyses for thorium were discovered primarily in 

claimant file records; only a few in vivo analyses were found. The thorium results 

are questionable because of the lack of information for readily interpreting them 

(e.g., there is no information regarding the in vitro separation method or counting 

procedure/equipment, nor is there information regarding the assumptions made to 

derive the in vivo results). 

2- It is known that respiratory protection (both preventative and following MAClevel air sample results) was provided and would have resulted in at least a factor 

of 10 protection when used properly. However it is also known that workers were 

exposed to >MAC levels without respiratory protection. Considering this 

information, standard respiratory protection factors cannot be assumed. 

3- Limited operation times and smaller volumes and mass (which also would 

presuppose a more effective ventilation confinement) reduced the exposure 

potential, all of which would result in an assumption for limited periods of higherlevel contamination. 

4- The MAC of 100 dpm m-3 (4.5 × 10-11 

μCi cm-3) is 20 to 100 times larger than 

the current derived air concentrations for 232Th. [TBD, Vol. 5, pp. 22–23] 

On this basis, the TBD states that the “recommended” approach is “claimant favorable” (Vol. 5, 

p. 23). These arguments are not compatible with the available data. Historical air concentrations 

of thorium were far higher than the then-prevailing maximum allowable air concentration for 

much if not most of the period of thorium production, and for many operations and locations. 

Historical daily weighted averages were also often above the then-prevailing MAC. It is unclear 

why the current standard is cited at all in the context of historical thorium intakes. It is not 

relevant to them. 

Thorium production was undoubtedly much smaller than uranium at Fernald; nonetheless, it was 

an industrial-scale operation and thousands of tons were produced there. As already noted, 

individual worker exposure is not connected to the level of production or capacity utilization, 

unless a plant is shut down for some of the time, in which case only resuspension doses are 

operative. 

We know that Plant 9 and the Pilot Plant specialized in thorium work during some periods. 

There is, therefore, no basis to restrict exposure time to a small fraction of the year for workers 

engaged solely or mainly on thorium production, as suggested by the dose reconstruction 

procedure in the TBD. Moreover, production data in the TBD are incomplete. 

Furthermore, the memorandum regarding drying of thorium in doorways and leaky equipment 

quoted above shows that high dust levels likely prevailed for considerable periods, even when 
 

 

 

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actual processing was not going on. The highly degraded condition of the thorium drums caused 

high dust levels during redrumming operations, and several of these were carried out over time. 

Even general air samples indicate thorium dust levels of ~ 1 to several MAC. For instance, the 

empirical lognormal average of five 1954 general air samples in Plant 9 production areas general 

air came was about 3 MAC (Plant 9 Survey 1954).3 

NIOSH’s conclusion that its approach is claimant favorable is partly based on its statement that it 

would assume that respirators were not used. However, this is not necessarily claimant 

favorable, since there is documentation that respirators were often not used even in the dustiest 

periods. This is acknowledged in the TBD. It is also implicit in the recommendation that 

respirators be worn in high dust thorium production areas. For instance a 1960 memorandum 

from K.N. Ross to J.E. Carvitti states the following: 

The attached evaluation shows that most of the operations performed in the 

thorium oxidation area are greater than the MAC.... It is recommended that an 

air dust survey of these operations be made to determine why the high dust air 

levels are not controlled. In addition, the results show that the dust levels on the 

sifting operation (not approved by the Fume & Dust Control Committee) are 

grossly inadequate and need correction. 

A dust type respirator should be worn while performing these operations until a 

new air dust evaluation shows the air dust levels to be less than the MAC. [Ross 

1960] 

NIOSH’s assumption that respirators were not used is moderately claimant favorable for the 

population of workers, but in view of the widespread non-use of respirators, it is not clear that 

that conclusion can be extended to individual workers. 

From the data cited above, one can conclude that some fraction of the thorium workers at 

Fernald were exposed to levels of several MAC, 50 MAC, or even 500 MAC as average 

exposures, with peaks of exposure running as high as 1,000 MAC to 3,500 MAC (see data tables 

above). The highest measurement of 1,260 MAC in Plant 6, for instance, attributed to manual 

raking of thorium residue into the Plant 6 furnace in 1962 (see Finding 1 above), would produce 

an intake in a single hour that would be greater than NIOSH annual estimated intake of 

1,050 MAC-hours. 

SC&A has not come across Type Super S thorium in the literature but it is possible that a highly 

insoluble form of thorium could be created during fires or machining. This possibility should be 

investigated. As noted above, thorium residues (including metal residues) were burned in the 

Plant 6 furnace. There were fires in thorium drums. Site expert interviews indicated that highfired thorium was present at Fernald (Attachment 4). The presence of high-fired (highly 

insoluble or Type Super S) thorium—that is thorium that is significantly more insoluble than the 

Type S currently defined in the literature—could make a significant impact on the thorium dose 

estimation for some organs. 

3

 The arithmetic average was about 22 MAC, due to one high sample. 
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Finally, there is also evidence of thorium fumes. A Plant 9 Health & Safety Division datasheet 

from 1954 describes the process as follows: 

Cutting thorium derbies in half by hacksaw. The operation is done dry and 

releases a considerable amount of fume in the area. Saw operator was without 

any type of respirator. [HSD 1954] 

The dust sample taken was a general air sample by the hacksaw and measured 2,544 dpm/m3

 or 

about 36 MAC. Therefore, it is important to consider inhalation for fumes for metal cutting 

processes. 

In summary, the method for intake estimation suggested by NIOSH is not adequately supported 

by the data or by scientific analysis, and may not be claimant favorable. The data in the TBD are 

incomplete and inadequate to make estimates of thorium intakes from 1954 to 1986. A 

resuspension model is needed for all periods, including the post-1986 period. The completeness 

and adequacy of lapel sampling data remains to be demonstrated for workers monitored for 

thorium in the post-1986 period. 

5.2 ISSUE 2: HIGH-GRADE ORE PROCESSING WASTE STEAMS 

5.2.1 Raffinate Intake Estimation Method 

Finding 7: The TBD does not specify a method for estimating doses in the raffinate 

streams, which are uranium-poor, from ore processing in Plant 2/3. These doses may be 

very difficult to calculate, especially for high-grade ores, notably pitchblende ore from 

Congo. 

Fernald processed high-grade ores, including pitchblende, which was processed during the 1953 

to 1955 period (TBD Vol. 5, p. 7). These ores, being very rich in uranium (up to two-thirds 

uranium oxide content), therefore also have high concentrations of Ra-226 and Th-230, which 

are decay products of U-238 generally present at levels close to equilibrium with U-238. 

Similarly, they have relatively high concentrations of protactinium-231 and actinium-227 (and its 

decay products, thorium-227 and radium-223), all of which are in the decay chain of 

uranium-235. Processing of high-grade ores gives rise to waste streams that are high in the 

decay products of U-238 and U-235, but relatively low in uranium, which is part of the product 

stream. 

Essentially no personnel monitoring for the decay products of U-238 and U-235 was done in the 

period of production when ores were handled at Fernald. The TBD cites some air concentration 

data for Plant 2/3 (Vol. 2, pp. 21–22), but these are in production areas, not waste stream areas. 

Unlike production areas, where uranium bioassay data can provide at least a starting point for 

internal dose reconstruction, such data are not very useful in determining dose of decay products. 

Uranium is a minor constituent of the waste streams in terms of its fraction of the total 

radioactivity per gram of material. This is accentuated by the fact that the DCFs for most organs 

of the trace constituents are much larger than they are for any of the isotopes of uranium present 

in natural uranium. 
 

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The TBD has data on the isotopic composition of the waste streams as present in an aggregated 

form in the K-65 Silos, also called Silo 1 and Silo 2. These data can be used to estimate doses in 

the absence of personnel monitoring data, provided sufficient air concentration data are 

available. However, no such data are cited for the processing waste streams in Plant 2/3.4 The 

TBD cites the decay products that are the radionuclides of concern for Building 3E, where 

raffinates were processed. However, there are no data that would be useful for estimating doses 

due to these radionuclides in the TBD. 

The problem of estimation of doses for production workers who worked at the filter presses and 

other locations where the waste streams were handled was dealt with by SC&A at length during 

consideration and review of the MCW SEC Petition (1949–1957 period). NIOSH also 

considered it in detail as part of that same process. The analyses and reviews can be found in 

SC&A 2005a and SC&A 2005c. The dose reconstruction procedures suggested by NIOSH as 

well as illustrative examples are in the attachments to SC&A 2005c. A review of those 

procedures can also be found in SC&A 2005c. 

While some of the analysis in the MCW-related reports is specific to that site, given that residues 

sent to storage were brought back to the site and reprocessed for uranium extraction, the primary 

discussion relating to pitchblende waste streams applies here and will not be repeated. Suffice it 

to say that uranium bioassay data provide an uncertain basis for estimating internal dose, due to 

the trace constituents in pitchblende processing waste streams. For such data to be used at all, 

knowledge is needed of the fraction of uranium relative to the other radionuclides at various 

points in the waste stream. Furthermore, these data need to be rather reliable, because the dose 

depends greatly on accurate (or upper-bound) knowledge of the ratio of trace radionuclide 

activity to uranium activity. No relevant data specific to Fernald are provided in the TBD, and 

SC&A has not come across any in the course of this review. 

One alternative approach that NIOSH suggested in the context of Mallinckrodt was to use radon 

breath data. Such a dataset was available for a subset of Mallinckrodt workers. The Fernald 

TBD mentions that “a series of radon breath samples” were located in the context of a discussion 

of the composition of the K-65 silos (TBD Vol. 5, p. 26); however, the data are not provided, nor 

is it clear whether any of the workers who processed the waste streams in Plant 2/3 were covered 

by the sampling program. 

As it stands, the TBD has no procedure in place and no data on which to base one for estimating 

doses to workers involved with ore processing waste streams.5

 It is to be noted in this context 

that one of the statements made by SC&A in the Mallinckrodt context was that using the general 

approach for estimating maximum plausible doses using ORAUT-OTIB-0002 may result in 

doses smaller than the ones actually experienced by some workers. 

A check of some completed dose reconstructions for Fernald using a maximizing method where 

the claim was denied revealed that NIOSH frequently uses the approach of assigning 

4

 There are some air concentration data for the period when Silo 1 was loaded with the K-65 residues 

brought to Fernald from Mallinckrodt Chemical Works. The citation and use of these data has been cited here as 

one of the strengths of the TBD (see Section 4). 5

 This includes all workers, including maintenance workers and roving trades employees. 
 

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hypothetical 12 or 28 radionuclide intakes based on OTIB-0002, as it did in the case of 

Mallinckrodt. The DCFs for some organs for thorium-230 and protactinium-231 (and in some 

cases Ac-227) are orders of magnitude greater than those for U-234 or U-238. Although 

thorium-230 and some other radionuclides of concern here are part of the hypothetical 12 and 28 

intake lists, it is not clear that the assumptions in OTIB-0002 are claimant favorable for the more 

highly exposed workers at Fernald, such as those exposed to certain raffinate and residue 

materials or to high levels of thorium-232 dust. Hence, NIOSH should verify that the doses 

using OTIB-0002 (meant only for efficiency purposes in cases that are likely to be denied) are 

actually higher for organs such as bone surface than would be the case were the intakes estimated 

from Fernald raffinate operations (including K-65 silo related work). 

5.2.2 TBD Guidelines for Estimating Raffinate Exposure 

Finding 8: Workers who may have worked with raffinates may be missed by the protocol 

specified in Vol. 5 of the TBD. The guidelines for determining which workers were exposed 

to raffinate dusts are too restrictive and place far too great a reliance on completeness of 

records for job assignments, or in the alternative, place the burden of proof on the 

claimant. They have not been adequately justified by measurements and are not claimant 

favorable. 

It is argued that internal exposure to K-65 raffinate dust would have been associated with 

external exposures of several hundred mrem per week: 

Calculations of internal intakes resulting from exposures to the raffinate dusts 

generated during dumping operations should be used only for claimants for whom 

a work history on this specific project can be established. An examination of 

external penetrating radiation dose for workers who were known to have worked 

with and handled these drums of raffinate wastes show significant (several 

100 mrem per week) penetrating dose accumulation. Therefore a criteria to 

determine and/or verify that a worker had indeed been exposed to internal intake 

from raffinate dusts would be a record of penetrating external dose, i.e., no 

detectable dose would clearly indicate little direct contact or work with the 

barrels of waste. [TBD Vol. 5, p. 27] 

However, exposure to dust could have occurred at some distance from the drums and would have 

been strongly dependent on the ventilation conditions, whereas the external dose rate would have 

fallen off substantially with distance. Although it is agreed that no detectable dose would 

indicate little direct work with the barrels of waste, how should the dose reconstructor address 

workers with modest levels of external exposure, say 50 mrem per week, in terms of their 

potential exposure to dust? 

The protocol for assigning internal dose only to those workers whose records show that they 

worked with the waste and whose records show that they worked with raffinates appears far too 

restrictive, based on the evidence provided. NIOSH should establish that “several 100 mrem” 

per week is an appropriate criterion for these workers. The prevailing maximum dose limit from 

the mid-1950s onward would have been routinely exceeded at any dose averaging over 250 
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mrem per week (assuming 1 week off every quarter). This seems implausible on the face of it. 

The criterion appears to be exclusionary. It needs to be better quantified—“several 100 mrem” is 

far too vague—and justified based on worker external dose records. Furthermore, NIOSH needs 

to demonstrate that available DOE records have the kind of detail concerning job assignment 

information that would enable a dose reconstructor to make a determination of work with 

raffinates in a claimant-favorable way. 

A set of criteria that is clear, technically well-founded, and claimant favorable is needed to 

determine who worked with various raffinate streams and, in particular, who may have been 

exposed to high Ra-226 and Th-230 raffinates. 

The time of the operation—10 weeks maximum per year, with an upper limit for individual work 

of 6 weeks—is not well justified, given the importance of the topic. To say that the work “could 

have been limited to a period of 10 weeks per year” seems a rather weak basis for limiting 

exposure time. NIOSH should provide the data on which these times are based, so that the 

technical reasoning is more transparent and justifiable. 

Furthermore, external exposure guidance for determining who worked with raffinate dusts is 

only applicable (if suitable criteria can be developed) to waste streams containing high 

concentrations of Ra-226. It does not adequately address the waste streams arising from RU 

processing. 

Finally, the guidance for the mix of radionuclides to be used needs clarification on two points. 

The TBD refers to Table 5-16 for the choice of the mix of radionuclides to be used in assigning 

the 1.3 microcurie estimated intake per year (Vol. 5, p. 25 and p. 27). First, this reference is 

ambiguous, because it does not specify whether the data for Silo 1 or Silo 2 should be used. 

Second, the guidance should make it explicit that the intake of beta emitters in Table 5-16 would 

be in addition to 1.3 microcuries per year, which was developed based on alpha dust data. This 

is indicated in the present text, but is not explicit. 

5.3 ISSUE 3: ESTIMATION OF DOSES FROM RECYCLED URANIUIM 

5.3.1 Recycled Uranium Trace Contaminant Data 

Finding 9: The data on trace contaminants in RU in the Fernald TBD are incomplete and 

appear to be incorrect. Different official documents have very different values for various 

aspects of RU data, including production and contamination. The contradictions have not 

been sorted out in the TBD. 

The TBD cites considerable data on the contamination of RU with trace amounts of 

plutonium-239, neptunium-237, and technetium-99. However, these data are incomplete. The 

representation of maximum trace contamination is at variance with other official documents and 

appears to be incorrect. 

Table 5-9 of the TBD (Vol. 5, pp.15–16) provides data on plutonium-239, neptunium-237, and 

technetium-99 contamination of various source of RU received at Fernald. The data are given in 
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parts per billion of the trace contaminant in uranium, written as “ppb U,” which we will 

abbreviate here simply as ppb. The highest value of Pu-239 contamination, associated with 

uranium trioxide from tower ash from Paducah is given as 412.177 ppb (TBD, Vol. 5, Table 5-9 

and p. 17). Several values of Pu-239 contamination are between 10 and 100 ppb, and the rest are 

below 10 ppb, which was the specification limit for Pu-239 contamination at Fernald. 

However, other documents are at variance with the maximum value of 412.177 ppb. For 

instance, a 1985 compilation of RU feed materials above 3 ppb U received at Fernald, prepared 

by National Lead of Ohio (NLO), gives the highest total plutonium contamination in “ash” for 

1980 as 1,122.553 ppb (Spenceley 1985, Attachment D). Plutonium isotopes other than Pu-239 

would not contribute significantly to the ppb values; hence, it is safe to interpret the “Total 

plutonium ppb” in Spenceley 1985 as approximately equivalent to a Pu-239 ppb value. This 

reference does not provide details of other radionuclides. 

It is quite possible that both sources are incorrect. The TBD appears to be based on a DOE 

report on RU (DOE 2000). This DOE report states that the total uranium receipts at Fernald 

amounted to 362,581.8 metric tons (DOE 2000, p. ES-2). This appears to be inconsistent with 

materials accounting reports from Fernald. For instance, the cumulative receipts until the end of 

FY 1986 were stated by Westinghouse to be 606,931.9 metric tons (Bogar 1986, Table V). This 

materials account is consistent with others produced during the period of production and 

submitted to the AEC and the DOE. Hence, it is likely that the DOE 2000, which is the basis for 

the data on RU, is incorrect even for the basic value relating to uranium receipts at Fernald. 

We note here that the TBD also appears to have an incorrect value for uranium production at 

Fernald. Volume 1 of the TBD estimates the shipments of uranium metal at 170,000 metric tons 

and intermediate products at 35,000 metric tons. The materials account cited above provides a 

value of 594,699 metric tons cumulative shipments to the end of FY 1986. Furthermore, the 

total shipments of 205,000 metric tons in Volume 1 of the TBD are less than the estimate of 

246,683 metric tons of RU alone that the TBD states were received at Fernald (TBD Vol. 5, 

p. 13). The total amount of RU of 246,683 metric tons in DOE 2000 appears rather large. In 

contrast, the amount estimated in Spenceley 1985 is only 7,183.6 metric tons, cumulative 

through 1985. This is almost 30 times less than the value in DOE 2000. Finally, Volume 6 of 

the TBD contains an entirely different number for RU compared to Vol. 5. Citing a DOE 2003 

report on RU, it states that the receipts of RU at Fernald amounted to 17,966 metric tons. This 

matter is further discussed in Chapter 7. 

Since the last mentioned report (DOE 2003) was prepared in order to correct “some 

inconsistencies between quantities of RU shipped and the quantities received” (DOE 2003, p. v) 

in the DOE 2000 report, it is surprising that NIOSH did not employ the corrected report. The 

figures from this report are shown in Vol. 6 of the TBD (Table 6-2, p. 8); they indicate an overall 

average Pu contamination of the RU received at Fernald of 4.14 ppb. This is greater than all the 

average contamination values for enriched, natural, and depleted RU shown in Table 5-10, Vol. 5 

of the TBD (3.5 ppb, <0.1 ppb and <0.1 ppb, respectively), where the basis for the RU dose 

reconstruction is developed. Volume 5 of the TBD gives the overall average Pu contamination 

of RU as 0.9 ppb, which is only about 22% of the value in DOE 2003. 
 

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The overall average values for Np-237 and Tc-99 in Table 5-10 are also at variance with DOE 

2003 (Table A-9, p. 60, which is reproduced as Table 6-2 in Vol. 6 of the TBD). The 

concentrations of Np-237 and Tc-99 calculated from the DOE 2003 data are 319 ppb and 

7510 ppb, respectively, compared to 104 ppb and 1,346 ppb given in Vol. 5 of the TBD. 

Another contradiction emerges from the comparison of the values in Volume 5 of the TBD and 

DOE 2003. Since the overall value for RU receipts given in Volume 5 of the TBD is so much 

larger than that in DOE 2003 (246,683.1 metric tons versus 17,966 metric tons), the total 

contaminant content of RU estimated in Volume 5 of the TBD is much larger than that in DOE 

2003. Table 8 shows the comparison. 

Table 8: Comparison of Total Fernald RU Contamination, TBD, Vol. 5 vs. DOE 2003 

Total Pu, grams Total Np-237, grams Total Tc-99, grams 

TBD Vol. 5, Table 5-10 217.7 25,742.1 331,998.1 

DOE 2003, Table A-9 74.3 5,735 135,000 

Ratio, TBD/DOE 2003 2.93 4.49 2.46 

Volume 5 of the TBD is not only in contradiction to Vol. 6 of the TBD, but it is also at variance 

with what DOE claims is a more definitive DOE report on RU (DOE 2003), since that report was 

designed to correct earlier problems. SC&A has not done a review of the underlying data that 

led to the correction, since that would involve a major effort to review RU data across the 

complex. It is unclear at the present time how reliable the various figures for plutonium, 

neptunium, and technetium contamination (both as totals and in terms of concentrations) might 

be. 

An evaluation by Bechtel of RU shipped to Fernald from Paducah provides yet another set of 

values for RU contamination for a specific batch that do not match the values in Volume 5 of the 

TBD. This document provides a range of values of Pu-239 in “Feed Plant Ash” shipped to 

Fernald in 1980 from Paducah as 37 to 3,118 ppb (Bechtel 2000, Table 4-2.2, p. 51). The 

various containers of Feed Plant Ash were not mixed at Paducah, because the reported values 

were “calculated from results of 16 hoppers analyzed by FMPC” (Bechtel 2000, footnote to 

Table 4.2-2, p. 51). Hence workers handling and measuring the hoppers would have been 

exposed to concentrations of trace radionuclides during some time periods when the 

concentrations were far higher than the largest value reported in the TBD, especially if they 

worked with raffinate streams. Finally, the same table in Bechtel 2000 notes that data for 

plutonium contamination are not available for “Filter Cake” shipped to Fernald. Three other 

items have only blanks in the column for plutonium contamination. The higher trace 

contamination levels may adversely affect some workers, who were mainly in contact with them 

due to their work assignments or periods of employment. For others, long-term exposure to RU 

may mean that the values suggested by NIOSH are claimant favorable (see below). 

In summary, the contradictions and conflicting values in the RU data need to be investigated, 

before a reliable set of values for RU amounts and contamination can be established. 
 

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5.3.2 Recycled Uranium Trace Contaminant Radionuclide List 

Finding 10: The radionuclide list for RU in the TBD is incomplete. Furthermore, the 

concentrations of trace radionuclides in the raffinates, which are much higher than those in 

the feed material, are not adequately discussed. 

The TBD focuses on Pu-239, Np-237, and Tc-99 in its evaluation of RU. Other radionuclides, 

such as americium-241 and thorium isotopes (228, 230, and 232) are mentioned, but no data are 

provided (see Section 5.2.2, Vol. 5, pp. 13–18). The omission of thorium isotopes, and in 

particular thorium-230, may be of considerable significance. Furthermore, when RU is 

processed for its uranium content, the raffinates tend to accumulate the plutonium and other trace 

contaminants, including thorium-230. The raffinate stream contains little uranium. Hence the 

problem of dose reconstruction for workers who handled the raffinates is analogous to that of the 

workers who handled the waste streams from pitchblende ore processing. This problem was 

recognized at Fernald at least by the mid-1980s. For instance, a 1988 evaluation stated the 

following: 

The uranium feed would contain the trace of TRU impurity that was typical of 

recycle uranium. A portion of the TRU impurities would end up in the uranium 

product and a portion in the byproducts. The vast majority of uranium goes into 

the uranium product, but a small amount does end up in the byproduct. The end 

result is that the ratio of TRU to U is slightly lower in the product than it was in 

the feed, but that ratio is much higher in the byproduct than it was in the feed. 

[Hinnefeld 1988, emphasis added]. 

This problem of concentration of trace radionuclides in the raffinate stream is also recognized in 

the TBD, which cited an expert evaluation done in 1989 (Bassett 1989). In the case of 

magnesium fluoride feed, a note to Table 5-9 in the TBD states the following: 

Though the results in the table are all reported in ppb U, this measure is 

meaningless in subgroups in which there is very little uranium, such as 

subgroup 8, in which the MgF2 did accumulate some isotopes, but was low in 

uranium by design. [Vol. 5, TBD, p. 15] 

Despite the fact that the TBD states that trace contaminant values are “meaningless” when there 

is very little uranium present, the quantitative discussion in the TBD of RU dose estimation is 

focused primarily on the trace contaminant values of uranium feed material, rather than raffinates 

or magnesium fluoride. 

Thorium-230 has also been recognized as a specific problem in this regard. For instance, the 

DOE-commissioned evaluation of radiation doses due to trace contaminants in RU for the 

Paducah plant indicates that thorium-230 doses were among the highest in some circumstances. 

In that case, the maximum bone surface dose estimated for “ash receivers” was estimated as 

110 rem, about the same as that for Pu-239 and much higher than Np-237 (PACE/University of 

Utah 2000, Tables 7.10 and 7.11, pp. 76–77). As with the processing of ores, thorium-230 will 

tend to concentrate in the raffinate stream as well, exacerbating the problem. 
 

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A complete evaluation should also consider thorium-232, uranium-232, and uranium-236 as 

potential contaminants of RU. Specifically, U-232 is created as a neutron activation (decay) 

product of protactinium-231, and the DOE recommends that it be taken into consideration in RU 

assessments. This is both an internal and external dose issue, because U-232 decays into 

thorium-228 with a 70-year half-life. According to DOE-STD-1136-2004, the Guide of Good 

Practices for Occupational Radiological Protection in Uranium Facilities, U-232 presents the 

greatest external dose hazard in RU: 

The isotope in recycled uranium presenting the greatest potential radiological 

hazard from external sources is 232U. 232U is a daughter product of neutron 

activation of 231Pa. The health hazards of 232U are primarily due to the rapid 

buildup of gamma activity of its decay products, particularly from 228Th. The 

gamma activity buildup is both time and process-dependent. [DOE 2004, 

p. 2-15]. 

Given that the highest values of trace contamination with plutonium received at Fernald could be 

in the thousands of ppb, Table 5-9, which gives the values for plutonium in the various RU 

streams at Fernald, is incomplete and inadequate. The highest value of Pu-239 in this table, 

412.177 ppb, corresponds to feed material (ash) from Paducah. There is no discussion in the 

TBD of the specific batches of RU and the waste streams arising from them. Such an analysis is 

necessary for individual internal dose reconstruction for at least some groups of Fernald workers. 

5.3.3 TBD Guideline for Recycled Uranium Dose Estimation 

Finding 11: The suggested approach for RU dose estimation in the TBD is claimant 

favorable for many RU workers, but is not claimant favorable for others and for some 

periods; it is not based on an evaluation of the available data. 

The TBD proposes to use 100 ppb of Pu-239, 3,500 ppb of Np-237, and 9,000 ppb of Tc-99 as 

the trace contaminant concentrations to be added to uranium dose (TBD Vol. 5, p. 17). The 

basic approach is to use uranium bioassay data and add the doses from the assumed trace 

contaminant concentration. There are a number of problems with this approach. No personnel 

monitoring data are available for the pre-1986 period; bioassay and in-vivo data exist for the 

post-1986 period. Of those data, the in-vivo data are not of much use, since the detection limits 

for plutonium are very high. These issues are discussed in the RU section of the TBD 

(Section 5.2.2). 

First, a one-size-fits-all method of estimating doses due to trace contaminants in RU is not 

appropriate. Over the decades, shipments of RU appear to have varied in Pu-239 content from 

well below the specification limit of 10 ppb to orders of magnitude larger than that (possibly to 

several thousand ppb). Concentrations of Np-237 would tend to be 1 to 2 orders of magnitude 

larger. Hence, the suggested values would be very claimant favorable for some workers 

handling RU, while they may not be favorable for others. 

Second, the list of radionuclides in RU needs to include all important contributors to dose and 

not just intake. Very small proportions of Th-230, or Pu-239, or Np-237 can become the main 

contributors to dose for certain organs (bone surface dose for instance), because their DCFs are 
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orders of magnitude higher than the corresponding ones for uranium. Hence, it is important to 

know the trace contaminant concentrations with some precision. Alternatively, a value that can 

be demonstrated to be scientifically sound and claimant favorable may be used. This must be 

on the basis of a comprehensive evaluation of the data, which has not been done in the TBD. 

Third, the raffinate streams are not considered adequately in the TBD, which notes that these are 

known to concentrate the trace contaminants in RU. In the absence of more detailed data on 

trace contaminants in waste streams, uranium bioassay cannot be reliably used to reconstruct 

doses for RU raffinate workers. 

Other workers in some specific jobs not involving raffinate streams may have been exposed to 

TRU concentrations at much higher levels relative to uranium than those handling feed material. 

For instance, workers manually cleaned out crucibles in which uranium tetrafluoride was 

reduced to metal, according to SC&A site expert interviews: 

Chemical Operators had a wide variety of responsibilities. Some of the high 

exposure jobs included manning the dumping stations, cleaning equipment (i.e., 

dust collectors, reduction pots, crucibles, furnaces, reaction vessels, etc.), 

inventorying the rabbit hutches, and decontaminating areas when needed. 

Graphite molds were cleaned with a broom handle and steel wool. After the 

removal of the MgF2 from the uranium, individuals would stick their heads down 

as far as they could to clean the slag out of the pot. During this operation there 

was no respiratory protection worn. [from Attachment 4 of this report] 

[Emphasis added.] 

Uranium bioassay data would not be adequate to estimate trace contaminant doses in such cases 

without a very specific knowledge of the contaminant ratios for that particular operation. The 

TBD acknowledges as much in the note to Table 5-9 and provides one value of nearly 100 ppb 

plutonium-239 in magnesium fluoride slag. However, it provides no analysis to show that the 

recommended values for trace contaminants would be consistently claimant favorable for such 

workers or for others who worked with RU waste streams. 

Finally, the TBD correctly notes that dose reconstructors should assume the most claimantfavorable solubility type for RU contaminants (TBD Vol. 5, p. 17). It should be noted that these 

contaminants will often occur as traces in a uranium compound matrix. Thus, the full range of 

solubility classes for uranium should be considered; i.e., plutonium should be considered to be 

potentially in Class F form in this context, even though only Class M and Class S would 

normally be considered for compounds of plutonium. 

5.4 ISSUE 4: INTERNAL DOSES DUE TO URANIUM 

5.4.1 Enrichment of Uranium Processed at Fernald 

Finding 12: The TBD notes that uranium batches with enrichment greater than 2% were 

processed at Fernald. NIOSH’s assumption of 2% enriched uranium is claimant favorable 
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most of the time, but not for periods and batches when uranium of higher enrichments was 

processed. 

Uranium urinalysis at Fernald was done using the fluorometric method, which yields results in 

mass of total uranium per liter (TBD Vol. 5, Table 5-9, p. 30). This method is, therefore, unable 

to provide data on the enrichment of the uranium that was inhaled. 

Natural uranium, depleted uranium, and uranium enriched up to 10% were processed at Fernald. 

The TBD states that enriched uranium processing began in 1964, and adopts the following 

recommendation for default values for uranium dose reconstruction: 

In the absence of specific enrichment information, and considering the above 

available data related to processing experience of uranium enrichments at 

FEMP, the default assumption for time periods after 1964 is 2% enrichment for 

bioassay data in milligram quantities of uranium. Prior to 1964 natural uranium 

should be assumed. [TBD Vol. 5, p. 10] 

An assumption about uranium enrichment is necessary to derive the intake in terms of 

radioactivity from bioassay data. In so far as depleted and natural uranium and uranium of any 

enrichment less than 2% was processed after 1964, this default assumption is claimant favorable. 

However, there are two areas where it is not. 

First, Fernald materials accounts show that some enrichment uranium was processed there from 

1953 onward, though it was in relatively small quantities until 1958, when over 500 metric tons 

were processed (Bogar 1986). The TBD appears to be incorrect, both about the starting date of 

enriched uranium processing and about the amounts. In regard to the latter, the TBD states the 

following: 

Of the total quantity of uranium received and processed at FEMP <25% was 

enriched above normal (60,181 MTU of the total 246,683 MTU). Approximately 

95% (208 gms of the total 218 gms) of the Pu-239 which was received at the Site 

came in the enriched uranium receipts. (DOE 2000) [TBD Vol. 5, p. 10] 

This statement appears to confuse enriched uranium that came to Fernald as RU with all enriched 

uranium. DOE 2000, the report cited in the TBD paragraph quoted above, gives the total 

production at Fernald as 363,582 metric tons (rounded), of which 246,683 metric tons are stated 

to be RU (DOE 2000, p. ES-2). As previously discussed, the production figures in DOE 2000 

appear to be incorrect—at least they do not match the detailed materials accounting data 

submitted annually by Fernald management (both NLO and Westinghouse) to the DOE. For 

instance, Bogar 1986, which was the account up to and including FY 1986, gives the cumulative 

enriched uranium shipments up to that date of 126,317 metric tons (rounded), or just over double 

the amount cited in the TBD. The materials accounting data from 1986 show that enriched 

uranium was about 21% of the total shipment amount of 594,699 metric tons of all types of 

uranium (Bogar 1986). 
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Lack of knowledge of the enrichment may prevent accurate or claimant-favorable dose 

reconstruction in the case of incidents. For instance, the TBD suggests using an enrichment of 

2% for the February 14, 1966, incident, even though the enrichment was unknown. It does not 

provide any evidence that it was not more than 2%. It is difficult to see how such a dose 

reconstruction for this incident could be regarded as resolving the uncertainty in favor of the 

claimant. 

Finally, the TBD acknowledges that uranium enrichments up to 5% or even 10% were processed 

at Fernald, starting in 1965: 

In 1965, the FEMP became the official receiving station for uranium compounds 

of up to 5% 235U furnished by licensees. With the startup of enriched uranium 

operations in the refinery in 1966, more than 1,500 safe mass batches of up to 

10% 235U feed materials were prepared for drum digestion. This recycled 

uranium was known to contain traces of 237Np, 238Pu, and 239Pu. [TBD Vol. 2, 

p. 15] 

The difficulties arising from a lack of claimant favorability in the choice of an enrichment value 

that is too low for some workers and periods would be compounded in the case of recycled 

enriched uranium. This is because the uranium intake value is the basis for estimating the 

intakes of trace radionuclides. Hence, an underestimate of uranium radioactivity by a factor of 2 

would lead to a corresponding underestimate of trace radionuclide intakes. Given that the latter 

may be the most significant parts of internal dose in some situations, a modest underestimate for 

uranium could result in a large problem in the overall final result of internal dose. 

In summary, the following problems need to be corrected before a choice of enrichments can be 

considered claimant favorable: 

•	 The TBD needs to be revised to show the correct periods of enriched uranium processing. 

•	 The amounts of enriched uranium processed need to be corrected, presuming the annual 

materials accounts reports filed by the contractor were correct. 

•	 The dates and amounts of uranium over 2% enrichment need to be established, so that an 

appropriate adjustment can be made for workers in those years (and Plants, if needed). 

5.4.2 Doses to Unmonitored Female Employees 

Finding 13: Female employees were not monitored for long periods at Fernald even though 

they were at some risk of internal intakes of radionuclides. 

Vol. 5 of the TBD does not discuss whether female employees were provided with bioassay 

monitoring. However, Vol. 6 of the TBD notes that there was no external dose monitored for 

female employees from 1951–1960 and again from 1969–1978. For instance, women who 

worked in the laundry or as laboratory technicians were at some risk of exposure. However, 

there are no data in the TBD as to when women worked there. NIOSH should also establish that 

there were women that were not assigned production work during periods that they were not 
 

 

 

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monitored. There is a photograph of a female employee taking a sample from an ingot in a 

production area that dates from the 1980s (del Tredici 1987, Plate 18). While this is from an era 

when women were monitored, according to the TBD, it is not far from the time (1978) when 

none were. A closer look at the frequency of bioassay monitoring for women employees in 

production work is also warranted. 

Furthermore, the above discussion on fugitive emissions for thorium indicates a work 

environment that had considerable ground-level radioactive dust from production, at least during 

some periods of operation. Female employees and other unmonitored workers may have inhaled 

such fugitive dust, which would also not be captured in the environmental dose (see Section 5.7). 

The TBD needs to take explicit account of the various categories of work done by female 

employees in order to develop a suitable model for internal intake estimation. SC&A has not 

been able to address the feasibility of development of such a model, because there is no overall 

database where bioassay data and in-vivo counts have been collected. 

5.4.3 Periodic Extremely High Uranium Dust Concentrations 

Finding 14: The TBD does not address the extremely high uranium dust concentrations, 

which were present at Fernald under a variety of circumstances, and their effect on dose 

reconstruction. Particle size and solubility assumptions for workers who experienced chip 

fires should be examined. 

There is ample documentation of very high dust levels at Fernald at least in the initial two 

decades in several of its plants and a variety of operations. Some of the documents are provided 

in the Fernald SEC Petition (2005) and will not be cited here.6

 Some of the highest dust levels 

occurred during periodic maintenance or repair operations. For instance, the recovery of parts of 

a broken main screw in a Plant 4 reactor (where UF4 was made) in 1967 produced dust levels as 

high as 171,770 dpm/m3; the averages for the various operations that were needed for the repair 

work ranged from 40 dpm/m3

 (12 feet from the reactor where “no work [was] being done”) to 

over 45,000 dmp/m3 (“[r]aking loose oxide into catch pan, vacuuming talc & shoveling oxide 

into drums”). No overall average is provided. (Jones and Keim 1967). 

A periodic maintenance operation in Plant 5, cleaning out uranium oxide under a conveyor, 

produced an average of 359 MAC (about 25,100 dpm/m3) over the 5-hour operation. This meant 

that almost an entire working-year’s intake (at 1 MAC) would be accumulated in that single 

operation (assuming a 2,000-hour work year). Some workers who did the most hazardous jobs 

likely accumulated higher intakes. The average dust level faced by the “[o]perator cleaning out 

under [the] burnout conveyor” was 18,000 MAC. This was reported as a significant 

improvement over the prior year, when the same operation averaged 97,000 MAC, which would 

give an annual intake at 1 MAC in just about one-and-a-quarter minutes of exposure. (Klein 

1960). 

6

 The law firm of Waite, Schneider, Bayless, and Chesley in Cincinnati, which represented Fernald workers 

in a class action lawsuit in the 1990s, has a large archive of documents regarding working conditions at Fernald. 

The Fernald SEC Petition (2005) has evidently drawn on this archive. This archive contains both air dust data and 

individual worker bioassay data. It may be useful in validating whether the bioassay data are sufficient to provide a 

claimant-favorable dose reconstruction for internal dose. 
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Some routine operations, like grinding and machining of uranium metal in Plant 6, produced dust 

levels in the hundreds to thousands of times MAC in 1952. High dust levels in routine 

operations often triggered investigations and ventilation improvements, however. The same 

operations showed lower dust levels in 1953, but still in the range of 39 MAC to 154 MAC 

(Heatherton 1953). These 1953 levels apparently persisted through most of the year and possibly 

beyond, since Fernald was not “scheduled to do any further checking at this time [November 

1953] in the machining section unless it is believed absolutely necessary.” (Heatherton 1953a) 

NIOSH has informed SC&A that there are ample uranium bioassay data for Fernald. These data 

have not been compiled for the site, so SC&A is unable to make a judgment of the sufficiency of 

the available data for claimant-favorable dose reconstruction, notably in the context of certain 

conditions prevailing at Fernald, such as the very high episodic dust levels discussed above. 

Furthermore, an assumption of a mid-point intake in such a case may be more claimant favorable 

than assuming a chronic intake (Puncher et al. (in press); Strom 2003). NIOSH should explicitly 

investigate the choices for claimant-favorable assumptions in case of episodic high intakes when 

the date of intake is unknown. If urinalysis was not done following such high episodic intakes, 

much of the uranium could be excreted prior to the next routine sampling. Frequency of 

sampling and sampling after work in unusually dusty conditions are, therefore, an important 

consideration in the use of bioassay data. 

The TBD does not provide guidance to the dose reconstructor on the problem of factoring in high 

episodic intakes (as distinct say from large daily variations in exposure that are typical of a job). 

If the time of an acute intake is unknown, the most claimant favorable approach is to consider an 

acute intake on the day following the last monitoring result. This should be specified as part of 

the dose reconstruction procedure for infrequent, high acute intakes. The issue of whether the 

DOE files of the claimants contain sufficient data to determine whether such intakes also need to 

be assessed. 

Furthermore, uranium monitoring at Fernald was done mainly for its heavy metal toxicity to the 

kidney (TBD, Vol. 5, p. 12). The MDL for uranium using fluorophotometry was high—14μg/L. 

With such a high MDL, rather high exposures from Type S uranium would not have been 

detected. In addition, urine samples were submitted after at least a 2-day work break (TBD 

Vol. 5, p. 28); this allows elimination of uranium to be cleared rapidly via the GI tract, a 

procedure that makes the detection of uranium contamination even more difficult. Finally, when 

using bioassay data, Type S solubility may be more claimant favorable than Type M for nonmetabolic organs. The dose reconstruction procedure for using the available bioassay data 

should consider these factors carefully. Some examples will illustrate these points. 

Consider the following description of a uranium fire in 1956: 

Specifically, a drum of fines located under the chip crusher ignited. By the time 

the burning drum was removed from the building (approximately 2 to 3 minutes 

later), the machining bay air was heavily laden with smoke and fume. Personnel 

did not evacuate immediately but remained in the area 7 to 8 minutes after the 

fire started. No one was observed wearing a respirator until several minutes later 

and then only a few. When evacuation was made it was for a very short duration, 
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perhaps 18 minutes, and when re-entry was made the room air was still visibly 

contaminated. [Stefanac 1956] 

This fire may have created submicron-size fumes. The TBD acknowledges frequent uranium 

metal fires (Vol. 5, p. 9), but provides no guidance on the particle size distribution to be used for 

chip fires. If they are considered among the principal sources of exposure for certain workers 

due to the frequency of fires, then the issue of exposure to fumes could have considerable 

significance for them. 

Similarly, the question of exposure to high-fired uranium needs explicit guidance in the TBD. 

The TBD acknowledges the presence of high-fired uranium as one of the chemical forms present 

at Fernald (TBD Vol. 5, p. 11), but provides no guidance regarding the dose reconstruction 

procedure or model to be followed. 

The issues of extremely high episodic exposures in certain jobs (such as those noted above), 

particle size (notably as a result of fires), the presence of high-fired uranium together could make 

a substantial difference in the dose reconstruction protocol, especially routine sampling was 

infrequent for workers with high potential for episodic intakes and sampling was not done after 

such intakes. The TBD does not provide guidance for dose reconstructors to address these 

problems. 

Finally, the availability of a significant amount of air dust data from various parts of Fernald 

could enable NIOSH to partly validate its approach to estimating uranium intakes from bioassay 

data. 

5.5 ISSUE 5: INGESTION DOSE 

5.5.1 Ingestion Doses and the TBD 

Finding 15: Ingestion doses are not considered in the TBD. 

NIOSH proposes to use bioassay data for estimating internal doses due to uranium. Urinalysis 

data would capture the inhalation as well as ingestion pathways. However, the TBD proposes to 

use air concentration data for thorium dose reconstruction (see above). Whenever air 

concentration (rather than bioassay) data are used, it is also important to consider ingestion dose 

separately, since this is an additional pathway that is not captured by inhalation assumptions. 

Fernald had heavy air dust loads, including from thorium-232 production. Therefore, ingestion 

doses from thorium-232 need to be explicitly considered, unless sufficient personal monitoring 

data are also found for thorium. 

The dust at Fernald would be expected to be a mixture of uranium and thorium, with the former 

predominating. An approach for considering mixtures was suggested by SC&A as part of its 

review of the Bethlehem Steel Site Profile (SC&A 2005e, p. 21). NIOSH may want to consider 

a similar approach for estimating thorium-232 ingestion intakes for Fernald. 
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5.6 ISSUE 6: EXTERNAL DOSE 

5.6.1 External Dose Reconstruction Protocols 

As a prefatory remark to external dose findings, SC&A notes that Findings #16 through #20 are 

largely concerned with skin/shallow dose. The findings are made as technical arguments, but 

their impacts on potential claims may be modest. For example, while skin dose to the palm of 

the hand is likely to be underestimated, there may be few, if any, claims of skin cancer located in 

that area. However, since the procedure in the TBD is not adequate for estimating such doses, in 

case there are any claims, SC&A concluded that a technical review of the matter was necessary 

as part of this TBD review. 

Finding 16: Protocols for reconstructing shallow external dose during the operations at 

FEMP need to be further developed. 

The deep dose Hp(10) evaluation was made within the uncertainties of the dosimetric systems 

available at the time, and a large underestimation of Hp(10) appears to be unlikely. The TBD 

argues that the correction factor for the loss of low-energy photons in the shielded filter proposed 

in the TBD could be under 10% (Vol. 6, p. 13). It suggests a factor of 10% should be used to 

correct for this lost dose (Vol. 6, p. 23). Any uncertainty or underestimation resulting from this 

factor is likely to be small when compared to the Hp(0.07) lost dose. 

The evaluation of the shallow dose Hp(0.07) for the calculation of the POC for skin cancer 

should take into consideration the substantial missed skin dose due to beta-gamma emitters that 

were not registered by thorax or wrist extremity dosimetry. 

The reconstruction of the beta dose to other shallow organs (gonads, breast) for the evaluation of 

the POC for cancer formation should also take into consideration the geometry of exposure. 

There is considerable potential for missed dose due to high-energy beta emitters that arises due 

to the location of the source relative to the organ that would not be adequately registered in 

Fernald thorax or wrist dosimetry. 

5.6.2 Estimation of Extremity Doses 

Finding 17: Extremity doses appear to be underestimated. 

From the nature of the work at Fernald, the hands and forearms of the workers received the 

highest external doses. The TBD details the dosimetry performed to estimate these extremity 

doses; however, the calculation procedures given in the TBD will substantially underestimate the 

extremity dose. 

For Fernald work with open sources, beta radiation was the highest contributor to extremity dose. 

Information is given in the TBD on measured beta dose rates at the surface of uranium metal 

ingots—around 240 millirem per hour. All open sources of uranium and thorium products 

showed high beta dose rates. Where uranium and thorium decay products accumulated in a part 

of the process, the beta dose rates were considerably higher. The TBD acknowledges this fact 

(Vol. 6, p. 14), but provides no guidance to the dose reconstructor on this point. 
 

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The higher dose rates in areas and job types where the beta-emitting daughters of U-238 are 

concentrated could be a considerable problem in dose reconstruction. The DOE’s Guide of Good 

Practices for Occupational Radiological Protection at Uranium Facilities, DOE-STD-1136­

2004, makes the following observations on this point: 

Processes that separate and sometimes concentrate beta-emitting uranium 

daughters are not uncommon in DOE uranium facilities. Surface beta dose rates 

on the order of 1 to 20 rad per hour have been observed in such circumstances. 

Exposure control is complicated by the fact that considerable contact work takes 

place in facilities that process uranium metal. Beta particles are shielded by 

rubber gloves or other protective devices or are usually absorbed within the dead 

layer of skin. The actual beta dose to live tissue would depend on the energy of 

the beta particles and the thickness and types of intervening shielding. [DOE 

2004, p. 6-7] 

In view of the above information, it is safe to say that some areas of Fernald were likely to have 

contact shallow dose rates between 4 and 80 times the contact dose rates for massive uranium 

ingots where the decay products have not been concentrated. The TBD identifies these as 

follows: 

The forms of radiation encountered at FEMP varied from plant to plant with 

Plants 5 and 9 exhibiting the highest potential workplace dose rates. These plants 

were involved with metal reduction, casting, and rolling, and these processes 

generated the separation and migration of daughter products 234Th and 234Pa 

(UX-1 and UX-2). As stated above, 234Pa contributes approximately 95% of the 

total beta dose rate; therefore, any location in the process where this material 

accumulated resulted in the potential for higher exposure rates. Other areas of 

potential high radiation exposure included areas where daughter products 

contaminated other materials (i.e., crucibles, saws, and rolling mills), or where 

large quantities of the parent material were present. [TBD Vol. 6, p. 15] 

External beta radiation is important at Fernald, especially in areas where there would be direct 

contact with concentrated decay products of uranium, Th-234 and Pa-234m, with the latter being 

the main source. Completeness of extremity monitoring or estimation methods that can derive 

extremity doses in claimant-favorable ways are, therefore, very important. SC&A’s review of 

the TBD, as well as some claimant files, indicates that there are a number of ways in which the 

extremity doses would be underestimated if the guidance in the TBD were followed. 

Completeness of Extremity Monitoring 

No finger monitoring was conducted at Fernald. Wrist monitoring was conducted for some 

workers, but did not cover all workers. A review of the DOE records in the files of about 

15 claimants working during various periods from 1952 onwards into the 1980s did not reveal a 

single case of wrist badge data in the claimants’ DOE files. The job types included chemical 

operator, laborer, pipefitter, machinist, carpenter’s helper, electrician, degreaser, supervisor, and 

millwright. The shallow wrist doses recorded for these workers per year or over their work 

period ranged from a few rem up to 60 rem, with many well over 10 rem. Wrist monitoring 
 

 

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appears to have begun around 1970. SC&A could find no wrist badge data on the NIOSH Site 

Research database prior to that time. No such data were found in a very limited search of the 

DOE files in claimant records. 

The TBD does not discuss the problem of missed extremity doses. This is a significant gap, 

because it is clear from the available data that in certain areas, the exposure potential for 

extremity doses was high. For instance, the compilation of beta plus gamma wrist badge results 

for October 1972 shows a range of wrist badge readings between 535 and 6,700 millirem for the 

month.7

 The data for November indicate most wrist doses in the several hundred-millirem 

range.8 At these rates, wrist doses could reach hundreds of rem over the course of decades-long 

employment. The hand and finger doses would be even higher. 

The TBD needs to discuss how the problem of gaps in the data that appear to be substantial will 

be filled to estimate wrist dose. 

We now turn to the problem of connecting wrist dose with finger or hand dose. 

Finger-to-Wrist Dose Ratios 

The TBD mentions that finger-to-wrist ratios (correction factors) of 2.06 had been used at 

Fernald after 1988, and that a correction factor of 3 might have been used previously (Vol. 6, 

p. 10). It then goes on to say that as the fingers are shielded behind gloves (shielding factor of 

20%), and the extremity dosimeter was not, the values of Hp(0.07) would overestimate the dose 

to the fingers, and therefore are claimant favorable. However, the following requirements for 

beta dosimetry are necessary before such an assumption can be made: 

•	 There must be no material between the beta emitter and the detector (film emulsion or 

TLD). 

•	 The distance between the beta emitter and the finger, and the beta emitter and the detector 

has to be very similar in order for the measured dose to correspond to the real dose to the 

extremity. 

•	 The angle of incidence of the beta radiation to the detector has to be close to normal 

(90o

). This applies to film dosimeters and also to calcium sulfate TLDs, which are 

usually formed into thin cylindrical or square wafers. The plastic shielding on the side of 

the dosimeter will also absorb most if not all the beta particles. 

•	 The wrist dosimeter must always be worn on the palm side of the hand. If it were worn 

on the back of the hand, no beta dose would be registered. 

When all these factors are taken together, the following conclusions can be drawn: 

7

 The document has no title, but is a compilation of datasheets. It is numbered 1713 on the NIOSH Site 

Research database with the title “Wrist and Film Badge Data (October 1972),” and has 6 pages. The data referred to 

are on page 1 of the file, with the notation that the badges were worn between September 12 and October 10, 1972. 8

 NIOSH Site Research database document number 1704: “Wrist and Film Badge Data (November 1972).” 
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•	 Case A: When holding a beta source in the gloved hand, essentially no dose will be 

recorded on the wrist dosimeter. It is not possible to estimate a correction factor. 

•	 Case B: When cleaning or polishing a beta source (such as a uranium metal bar) with a 

gloved hand, the wrist dosimeter will be close to the surface. The dose recorded will 

provide a reasonable estimate of the real dose to the fingers. The correction factor would 

be close to one. 

•	 Case C: For other geometries, the correction factor will be between one and such a large 

number that the use of a correction factor is inappropriate. 

The correction factor lies between 1 for case B and some high number for case A. In the latter 

case, the correction factor is not meaningfully defined, since the recorded dose on the wrist 

dosimeter will be very low or zero. Such considerations make the use of correction factors for 

hand and finger doses unreliable and impractical. A better and more consistent way of 

approaching the problem would be to estimate the finger and hand doses on a case-by-case basis 

in case of skin cancer of the hand. For workers that operated or performed maintenance on 

equipment with high concentrations of decay products of U-238 or Th-232, the annual beta dose 

to the skin of the hand could be as high as a few hundred rem. For other workers, handling 

metallic U products, the dose to the skin of the hand could be estimated as follows: 

240 mrem/hour × 2000 hours per year × the fraction of time the uranium was handled 

A similar approach can be developed for thorium-232. 

It can be seen from the above that an analysis of exposure geometry of the problem during the 

actual work performed is essential to the determination of a scientifically reasonable and 

claimant-favorable extremity dose. 

Contaminated Gloves or Non-Issuance of Gloves 

A second factor that can lead to an order-of-magnitude underestimation of the extremity dose is 

the question of glove contamination. The TBD refers to the problem of contaminated gloves 

only in the context of potential for exposure to Tc-99 beta dose (TBD Vol. 6, p. 9). However, 

even in this context, it does not provide guidance as to how the problem is to be addressed. In 

other contexts, the TBD only cites gloves as an element of clothing that provides a 20% 

shielding factor for beta radiation (TBD Vol. 6, p. 10). 

From the FEMP document on the decontamination of gloves (Wunder 1955), a sample of the 

gloves was monitored, and around 35% of the gloves measured showed a beta-gamma dose rate 

above 20 mrep/h, where 20 mrep/h was the maximum dose rate of the dose rate meter. As the 

gloves were not intended for contamination control, it may be assumed that the dose rate inside 

was the same as that outside. Some gloves continued to show above 20 mrep/h even after 

decontamination, which was estimated to have removed around 90% of the radionuclides. Using 

a conversion factor of 1 mrep = 1 mrem, this dose rate is equivalent to 20 mrem/h. Assuming 

that the workers would use the gloves around 2000 hours/year gives an annual dose rate to the 

fingers and palm of the hand for the users of these gloves at around 40 rem. Even if one 
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considers actual time of wearing gloves to be 1,000 hours, the annual missed dose to the hand 

and fingers would be 20 rem. The maximum doses in a few cases would be much higher. 

An interesting detail in the Fernald documentation was the proposed burning of used gloves for 

uranium recovery. This indicates generalized glove and workplace contamination. The beta 

radiation (the predominant part) on the gloves would not be detected by the wrist dosimeter. 

This would imply that for the workers who used gloves, the skin of the hand received an 

undetected dose, which can be considered around 20 to 60 rem/year, with a possible maximum 

being much higher. This dose should be considered as “background” and added to the beta dose 

to the hand received from the routine work with the uranium and thorium compounds. 

There is also some evidence, provided as a statement in the Fernald SEC petition, that the 

clothing issue record of an employee who routinely handled uranium metal for testing shows that 

he was never issued gloves (Fernald SEC Petition, Part 1, p. 19). 

The above discussion has been in the context of shallow extremity doses from uranium-238 

decay products. Similar considerations apply to external dose from Th-232 decay products and 

the process streams that concentrate Ra-228 and its decay product, Ac-228, with which it can be 

expected to be in equilibrium (due to the short half-life of 6.15 hours of Ac-228). In the case of 

Th-232, there is the additional problem of geometry of deep exposure when thorium-bearing 

materials were handled due to the higher contact gamma dose in this case (see below). 

5.6.3 Beta Dose to the Rest of the Body 

Finding 18: Beta dose to the rest of the body would also be underestimated, based on the 

TBD guidance. 

It appears from the supporting documentation of Fernald that the workers passed much of the 

working day with a substantial coverage of radioactive dust. Various documents provide some 

examples: 

•	 Dust samples from the chip furnace area showed contamination ranging from 0 to 

92,984 dpm/m3

, with averages at particular work locations ranging from 22 to 25,676 

dpm/m3 (0.3 to 366 MAC) (Heatherton 1953). Workers in such areas would likely have a 

heavy coating of dust. 

•	 In 1953, a worker was observed having “[h]is body covered with black dust, and the 

worker volunteered that this material was black oxide, U3O8, which he had encountered 

in cleaning the Bag House” (Durkin 1953). 

•	 A 1954 letter from W.B. Harris of the Health and Safety Laboratory noted “a general 

disregard on the part of the operators of the toxicity of the material. This is evidenced 

by...dust on desk tops, hood tops, and so forth; careless and sloppy handling of 

equipment containing uranium powders....spillage on the floors of small heaps of 

uranium salts” (Harris 1954). 

•	 Dust continued to be a problem into the 1980s. As discussed below, many TLDs were so 

coated with dust that an attempt to correct the external dose for this resulted in large 
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correction factors, often in excess of 50%, and sometimes in excess of 100% (yielding 

negative radiation doses). 

The work in the dusty conditions is, of course, a very important input for internal dose 

calculations. However, dusty work conditions also mean that the worker was almost 

continuously externally irradiated with beta-gamma emitters. This contamination would have 

contributed to the Hp(0.07) dose to the skin without being registered on the thorax or extremity 

dosimeters. This irradiation condition is not mentioned and quantified in the occupational 

external dose TBD. 

This generalized contamination led to beta doses to the rest of the body, which would not 

necessarily have been recorded by the thorax or wrist dosimeters. However, the TBD 

acknowledges the potential for significant beta dose to the skin: 

After reviewing the tables in this TBD it is possible to determine that the 

preponderance of the radiation consists of beta particles, and while this form of 

radiation can deliver substantial doses to bare skin in proximity it does not 

penetrate deeply into the body. The dose rate from the photon component 

associated with the radioactive decay of uranium is “minor compared to the beta 

dose rate” (Alvarez et al. 1984). In addition, protective measures such as 

distance, shielding, clothing, gloves, etc., reduce beta dose rates appreciably 

without excessive bulk by approximately 20%. [TBD Vol. 6, p. 10] 

This appears to imply the following: 

(1) The recorded values of Hp(0.07) as measured by the dosimeter located on the thorax are 

claimant-favorable 

(2) Only the beta dose to the skin should be considered. The beta dose to other body organs, 

notably the breast and the gonads, need not be considered 

Neither of these considerations is correct or claimant favorable. As to point (1) above, the 

Hp(0.07) dose recorded on the thorax dosimeter will be a small fraction of that actually delivered 

to the skin. Data on Hp(0.07) dose obtained from the thorax dosimeter in the following cases 

may be difficult to interpret in the following cases, if it can be done at all: 

(a) Dose due to directly handling uranium, as in the ORAUT-OCAS-001 example (OCAS001, p. 46), or directly handling other beta/gamma emitters 

(b) Dose due to a hot particle 

(c) Dose to the legs and hands while standing, sitting, or kneeling on all fours on a 

contaminated surface (in this case, the dosimeter being more or less perpendicular to the 

contaminated surface) 

(d) Dose when standing facing a uniformly contaminated surface if the distance of the 

dosimeter from the contaminated surface is significantly higher than around 50 cm. 
 

 

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There are some geometries where the dose of record would be useful; for instance, working in a 

confined contaminated space such as a pipe, vessel or duct, or lying face down on a 

contaminated surface. In these cases, the beta dose to the thorax dosimeter approximates the 

dose to the skin, if the beta energy spectrum is similar to the beta calibration spectrum. This 

presumes that the front of the thorax dosimeter was facing the contaminated surface. 

Evaluating the irradiation geometries above suggests that, unless the employee spent most of his 

day doing maintenance work in confined spaces or supervising a contaminated control panel, the 

Hp(0.07) dose to his or her thorax dosimeter due to beta radiation may have little relation to the 

real beta skin dose. 

The suggestion in the TBD (Vol. 6, p. 17) that the recorded external doses are claimant favorable 

over a wide range of angular variation of the incident radiation is generally not correct for the 

following reasons (apart from the geometry of the source relative to the organ exposed, discussed 

above): 

•	 The Hp(10) response for horizontal rotation goes down as the irradiation angle increases. 

There is a modest reduction of the response for the TLD dosimeter. However, this 

problem is much more serous for film dosimeters. 

•	 The dose recorded by TLD and film dosimeters goes down very quickly as a function of 

angle. It will fall to almost zero for side-on irradiations. This angular dependence is not 

at all claimant favorable, and will lead to considerable underestimation of Hp(0.07) dose. 

Considering organs other than the skin, the maximum beta energy emitted by some radionuclides 

(notably Pa-234m with Emax = 2.29 MeV) is high enough to cause a dose to the gonads, breast, or 

lens of the eye. Hence, an assessment of shallow dose is not only important for skin cancer 

cases, but also for other near-surface organs. SC&A has previously suggested that the thyroid 

also be considered as a candidate for shallow dose assessment (SC&A 2005a, p. 14). 

It is clear from the same arguments used above that the use of Hp(0.07) as measured with the 

thorax dosimeter to estimate the beta dose to the gonads or to the eye lens is appropriate only in 

some geometries. For all other geometries (for example, sitting on a uranium metal ingot), the 

Hp(0.07) dose recorded on the thorax dosimeter does not represent the real dose to the gonads. It 

is to be noted that sitting on ingots to stamp ID numbers was a practice followed at Fernald 

sufficiently frequently for an employee to allow himself to be photographed that way.9 Other 

examples of the problem of geometry, such as sitting on derbies, are provided in the Site Expert 

Interview Summary (Attachment 4). 

As a final note, the unreliability of the thorax dosimeter for beta dose and the lack of egress 

monitoring until the late 1980s would make it more difficult to reconstruct skin dose for 

personnel such as security guards, who would enter the site for a variety of reasons, such as 

escorting visitors. 

9

 Photograph by Robert del Tredici, taken in 1987. The photographs at Fernald, some of which were 

published in del Tredici 1987, were taken with the permission of management. NIOSH has agreed to evaluate the 

geometry issues connected with this example. See Attachment 3. 
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For the case of a claimant with cancer of the breast, gonads, or thyroid, a specific investigation 

should be made to estimate the relevant organ dose due to beta radiation. 

5.6.4 Geometry of Exposure 

Finding 19: The TBD does not analyze the special problems associated with geometry of 

the source relative to the exposed organ and dosimeter in thorium handling and 

production. 

In the case of Th-232, the problem of shallow and deep dose geometry is even more complex. 

Unlike uranium, both gamma and beta dose are significant for Th-232. Special exposure 

geometries, such as handling thorium metal, shoveling thorium chips into a furnace or 

withdrawing ash from a furnace, and handling drums containing thorium have considerable 

implications for interpretation of deep dose. A 1955 survey done at Fernald found the following: 

An attempt was made to compare the radiation from thorium with that of [sic] 

uranium, in which the surface dose is known. These measurements indicate that a 

gamma radiation level from thorium is approximately 10–20 times that from 

uranium, while the beta radiation from thorium is approximately 25% of that 

from uranium. Assuming a surface dose of 5 mr/hr gamma and 240 mreps/hr 

beta from uranium metal, I think we can say that the contact dose from thorium is 

in the neighborhood of 50–100 mr/hr gamma and 75 mreps/hr beta. [Heatherton 

1955] 

These estimates of contact dose from thorium would be considerably increased in the process 

streams, where the decay products of thorium were concentrated. In the case of thorium, the 

external dose problem extends into deep dose. The geometry of exposure and the relationship of 

hand dose, wrist dose, and the dose recorded on the main badge worn at the chest or lapel level 

becomes critical to a sound dose evaluation. The TBD contains no evaluation of this problem. 

5.6.5 Correction Factors during Initial Period of TLD Use 

Finding 20: Correction factors used during an initial period of use of TLDs at Fernald are 

not scientifically appropriate. 

Table 6-3 (Vol. 6, p. 9) states that the use of TLDs at Fernald began in 1985. However, the 

Westinghouse transition report on Environment Safety and Health indicates that film badges 

were used “prior to 1983” and that “the multi-element Panasonic badges were first used” in 1983 

(Westinghouse 1986, p. 14 and p. 16.) It appears therefore that TLDs began to be used at 

Fernald in 1983. 

In its response to SC&A questions, NIOSH/ORAU stated that the initial use of the TLD was 

experimental, and that these doses were not entered into worker dose records: 

The TLD model in question was one under development and was not the 

dosimeter of record. The TLD model that was finally put into service in 1985 was 

the first to be DOELAP certified. [Attachment 2] 
 

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SC&A cannot determine when the TLD measurements were first used as the dose of record. 

However, the Westinghouse transition report indicates that they had been in use for sometime by 

October 1985, and that until that date, correction factors were being used to adjust the dose to 

account for the dust deposited on the dosimeters: 

After an interval of one to several days, each tray of badges is surveyed for 

contamination. A beta-gamma survey instrument is used to screen the badges as 

they lay flat in the trays. If the badge reads more than 200 counts per minute on 

contact, it is taken out of the tray and deconned with alcohol and paper wipes. 

Badges which can be successfully deconned to below 200 c/m are returned to 

service. A record is kept of all badges found to be contaminated in excess of this 

200 c/m limit.... 

According to Bioassay Department personnel, about 100 badges per month are 

found to be contaminated above the 200 c/m limit. Most of these contaminated 

badges come from workers in Plants 5 and 4. Up until about 1 month ago 

(October 1985) an attempt was made to correct individual dosimeter results for 

contributions from contamination on the badge. A correction factor (derived 

from a study using 90 contaminated badges) was applied as a function of the level 

of contamination observed. Documentation of this correction is seen in 

Attachment 3. Any corrections which led to more than a 50% reduction [in dose] 

were brought to the attention of the Health Physics Department for their 

evaluation and approval. [Westinghouse 1986, p. 15] 

This indicates the routine use of TLDs, though the starting date of such use cannot be 

definitively determined. If the Westinghouse transition document is correct in stating that the 

use of film badges only occurred “[p]rior to 1983,” then it is likely that the TLDs began to be 

used routinely in 1983. It is possible that their use began later. This is a matter of some 

importance, since the correction factors were evidently incorrect. Their use actually sometimes 

resulted in negative radiation doses. Table 9 shows some examples of TLD measurements, 

corrections, and corrected result from the attachment mentioned in the above quote. 

Table 9: Some Examples of Corrections to Measured TLD Dose 

Correction Correction Uncorrected Corrected Badge # Gross 1

 Net 

mrem % mrem mrem 

A 2,000 1,900 532 65 821 289 

B 500 400 112 14 802 690 

C 1,200 1,100 308 41 759 451 

D 2200 2100 588 86 687 99 

E 700 600 168 114 147 -21 

F 1000 900 252 663 38 -214 

Source: Westinghouse 1986, Attachment 3. Badge numbers have been replaced by letters. 1

 - Survey meter reading. 
 

 

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The use of a formula to generate correction factors that resulted in negative radiation doses was 

obviously faulty;10 the practice was apparently discontinued in October 1985. It is unclear when 

it began. Hence, even if the dust had deposited very close to the time of submission of the 

badge, the number of days would be half the period. Thus, the correction would be too large in 

this case. The reverse was also possible, of course, in case most of the dust settled on the badge 

early in the wear period. 

It is unclear what was actually entered into the dose records when large percentage corrections 

were referred to the Health Physics Department. Moreover, the use of this correction factor was 

also inappropriate for those badges with less than a 50% correction factor. 

In the conference call of August 18, 2006, NIOSH/ORAU stated that they would investigate the 

issue. SC&A believes that the integrity of the external dose record from 1983 to October 1985 is 

open to question until this issue is resolved. 

As a final point, SC&A notes that the high dust levels on many TLDs are indicative of 

inadequate industrial hygiene conditions even in the 1980s. This fact reinforces the discussion in 

Finding 18 above regarding the potential at Fernald for significant unrecorded beta dose to the 

skin in areas other than the hands and fingers. 

5.6.6 Female Employees – External Dose 

Finding 21: The method for estimating external dose to unmonitored female employees is 

incomplete and its claimant favorability has not been appropriately demonstrated. 

The TBD states that the approach it describes for unmonitored employees, including women in 

the times they were not monitored, should only be applied to non-compensable cases. The 

guidance is to assign an external dose of 500 mrem/year. NIOSH states that this dose “is several 

times above the mean doses observed for monitored workers” and that, therefore, this value is 

claimant favorable (TBD Vol. 6, Table 6-14, p. 24). The TBD does not specify how the mean 

dose for monitored workers was estimated, since no database for such monitored workers has 

been compiled. Furthermore, it is not clear that the mean dose for all periods is a relevant figure 

to use for unmonitored female employees, because the lack of monitoring was in specific periods 

(1951 to 1960 and 1969 to 1978). The validity and claimant favorability of the suggested 

approach, especially for the early period, needs to be established by estimating the distribution of 

monitored worker dose in those periods. 

The problem of extremity doses for female employees who handled clothes contaminated with 

uranium-238, thorium-232, and some of the radionuclides in their decay chains is not addressed. 

This could be particularly important for beta exposures. No procedures for estimating such 

exposures are specified in the TBD. 

Finally, the TBD provides no guidance as to the procedure to be used for estimating doses to 

female employees or men who were not monitored in cases that may be compensable. There is 

10 A part of the problem was that the number of days that the dust was assumed to be on the badge was 

always taken as the days worn divided by 2. 
 

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explicit guidance that the 500 mrem per year is to be applied only to cases that are likely to be 

non-compensable: 

For unmonitored workers, 500 mrem per year will be assigned as an upper bound 

limit. This is several times above the mean doses observed for monitored 

workers. Since this dose is considered an overestimate, this upper bound will 

only be used in cases that will likely result in a Probability of Causation (PC) less 

than 50%. The applicable years this dose may be assigned are shown in Table 

6-14. [TBD Vol. 6, p. 24] 

NIOSH should specify a procedure for estimating doses for cases where best estimate doses are 

to be done. Furthermore, SC&A notes that Table 6-14 does not contain any entry for the period 

1969–1978; presumably this was an oversight and 500 mrem was intended, based on the 

discussion in the text. 

5.7	 ISSUE 7: OCCUPATIONAL ENVIRONMENTAL DOSE: INTERNAL – 

NON-RADON 

The fundamental approach used in the TBD for reconstructing environmental internal exposures 

of workers for 1951 to 1988 was to use published information regarding the annual atmospheric 

release rate of uranium, thorium, radon, and radon progeny from various point and area sources 

on the site, along with the application of standard Gaussian dispersion models, to reconstruct the 

airborne radionuclide concentrations at potential receptor locations onsite. Given these derived 

airborne concentrations, internal exposures were derived using conventional ICRP 

methodologies. The following presents a review of the methods used in the TBD to derive the 

source terms, followed by a review of the methods used to derive the atmospheric dispersion 

factors between the sources of the releases and the receptor locations, followed by the methods 

used to derive inhalation doses at receptor locations. 

5.7.1	 Uranium Emissions Source Term 

Finding 22: The source term for atmospheric uranium emissions from Fernald is 

significantly underestimated. 

The site profile refers to Boback et al. (1987) as updated by Dolan and Hill (1988)11

 and RAC 

(1995) as the bases for the estimated annual atmospheric releases. The Boback et al. report, as 

updated in 1988, was used for the uranium and thorium source terms, while the RAC report was 

used for radon emissions. SC&A notes that there was yet another update of this report that was 

done in 1989 that NIOSH did not use, even though it was part of the same series of 

contractor/DOE documents (Clark et al. 1989). 

11 The TBD erroneously refers to this publication as Dolan and Dolan 1988 (TBD Vol. 4, p. 9). The 

reference list for this publication should also be corrected from “Dolan, L.C. and C.A. Dolan...” to “Dolan, L.C. and 

C.A. Hill...” 
 

 

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According to Boback et al. (1987) as updated by Dolan and Hill (1988), the total uranium 

emissions for the time period 1951–1988 were 175,130 kg.12

 However, this source term, and the 

annual emissions estimates that comprise it, were incomplete and based in part on incorrect 

assumptions. The RAC (1995) study estimated uranium emissions to be about 310,000 kg (50th 

percentile) with a 90% confidence interval from 270,000 kg to 360,000 kg (RAC 1995, p. xii). 

The RAC estimates based on stack and scrubber data are in good agreement with soil data as 

shown in Appendix C (RAC 1998). 

A review of Boback et al. (1987) and Dolan and Hill reveals (1988) reveals a number of 

deficiencies, such as an assumption of manufacturer-specified efficiency for Plant 8 scrubbers 

and underestimation of unmonitored discharges. The problems with the official estimates in 

Boback et al. (1987) and Dolan and Hill (1988) are well documented and should be evaluated by 

NIOSH.13 In view of the fact that the CDC commissioned a study to review the Fernald source 

term and estimate offsite radiation doses, and that the best estimate in this study is about 75% 

larger than the estimate cited in Dolan and Hill (1988), it is surprising that NIOSH did not review 

the NLO and Westinghouse source terms more critically. 

The RAC study did not have estimates of thorium emissions. However, in view of the 

documented problems with the DOE and contractor estimates with the uranium source term, 

NIOSH should subject the Dolan and Hill (1988) thorium source term to a similar critical 

analysis. For instance, the thorium source term lists only Plants 8, 9, and the Pilot Plant as being 

sources (TBD Vol. 4, Table 4-3, p. 12); however, we know that Plants 4 and 6 were also sources. 

The emissions estimates need to reflect the full production history of thorium at Fernald; they 

also need to carefully consider issues such as baghouse and scrubber efficiencies in various 

periods. 

5.7.2 Modeling Environmental Dose 

Finding 23: The TBD has not adequately considered various aspects of internal 

environmental dose, including the applicability of the Gaussian model, episodic releases, 

and particle size. 

Episodic Releases 

Boback et al. (1987) states that the results of continuous stack sampling of each of the buildings 

were reported as monthly values, and then were summed to produce annual source terms. In 

view of the fact that releases were highly variable, the TBD would benefit from a discussion of 

variability in the source terms in order to address the issue of the effect of episodic releases on 

the dose reconstruction. For example, page 14 of the Boback report refers to an episodic release 

of 1,195 kg of UF6 on February 14, 1966. 

Data compiled by Weldon Adams in 1985 indicate that more than one-third of the then-estimated 

source term was attributable to relatively short-term releases (Adams 1985). Furthermore, data 

12 Clark et al. 1989 give an estimate of just over 179,000 kilograms, which is about four metric tons larger 

than the estimate in the TBD. 13 See RAC 1995 and Makhijani and Franke 1989. 
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for the early years are missing or incomplete. Some of these releases may have occurred over 

extended periods of days or weeks, in which case they may be modeled as continuous releases; 

but others may have been more truly episodic in the sense that they occurred in periods shorter 

than a day. Furthermore, the episodic nature of the releases needs to be assessed in the context 

of the RAC source term. 

Given that the episodic releases in at least some of the early years were likely to have been large, 

it is possible that significant environmental dose may have been received by unmonitored 

individuals in unfavorable weather conditions that would not be adequately captured by annual 

average dose. If a large portion of the emissions in a year came from a few short-term releases, 

then the environmental dose from episodic releases may dominate the intake for many workers. 

Details of timing and magnitude of the episodic releases, notably in the early years, may be 

important in developing a claimant-favorable approach to unmonitored environmental internal 

dose. 

The Gaussian Model 

For the purpose of deriving the environmental doses to workers outdoors on site, NIOSH divided 

the site into a grid consisting of 11 locations (see Figure 4-2 on page 14 of the TBD). Each point 

and area source is assigned a location within one of the 11 grid locations, and average annual 

atmospheric dispersion factors were derived for each receptor location within each of the 11 grid 

locations. Hence, the product of the average annual source term for a given plant (expressed in 

Ci/sec) with the average annual atmospheric dispersion factor (i.e., X/Q, expressed in sec/m3

) 

yields the average annual airborne radionuclide concentration (Ci/m3

) at any of the 11 grid 

locations due to atmospheric releases from any of the emission sources. 

In principle, this approach is conceptually valid. However, the report is silent regarding episodic 

releases, which would not be well represented by average annual Gaussian modeling. The 

application of average annual atmospheric dispersion factors could result in gross overestimates 

or gross underestimates of the doses associated with episodic releases. If the episodic releases 

were numerous and random, then the use of average annual dispersion factors is appropriate. 

The TBD would benefit from a discussion of this possible issue. 

The equation used to derive average annual atmospheric dispersion factors includes a term for 

elevated releases. Again, in theory, this is appropriate under some circumstances. However, as 

indicated in the TBD (Vol. 4, p. 17), a release height of 10 meters is used as input to the equation 

used to model elevated releases, resulting in near field (<500 meters between the source and 

receptor) atmospheric dispersion factors for elevated releases that range from about 2-fold lower 

to 9 orders of magnitude lower than ground-level atmospheric dispersion factors (see Table 4-6 

on page 18 of the TBD), depending on the distance between the source term and the receptor. 

The problem is, when the release heights are relatively low, as compared to the height of the 

buildings and structures in the vicinity of the releases, building wake effects negate the benefit of 

the elevated releases. Under these conditions, which appear to be the case for many locations at 

the site, ground-level atmospheric dispersion factors should be employed. The implications are 

that, for the close-in locations delineated in Table 4-7 on page 18 of the TBD, the atmospheric 
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dispersion factors may be significantly underestimated, resulting in significantly underestimated 

doses to workers at those locations. 

The TBD (Vol. 4, p. 17) states that atmospheric dispersion factors (X/Q values) were derived 

assuming a wind speed of 3.2 m/sec and stability Class F. Once the X/Q values were derived for 

a given distance between the release point and receptor (using the sigma y and sigma z values in 

Figures 4-3 and 4-4 of the TBD), an adjustment factor is applied to account for the frequency the 

wind blows toward a given receptor from a given source. This is a very crude method for 

deriving X/Q values. In one respect, it could be considered conservative, because stability 

Class F is assumed; however, this conservatism is offset by the use of an elevated release. By 

using stability Class F, the plume is assumed to have minimal vertical and lateral spread as it 

moves downwind. As a result, when the plume touches down to the ground (at about 500 meters 

downwind from an elevated source), the concentration of radionuclides in the plume is likely to 

be overestimated, because typical average annual meteorological conditions are not represented 

by stability Class F (i.e., one would expect that average annual conditions would reflect greater 

dispersion than those associated with stability Class F). However, before the plume touches the 

ground downwind, the ground-level radionuclide concentrations will be essentially zero (see the 

differences in the X/Q values between 100 meters and 500 meters in Table 4-6 of the TBD). 

Hence, for much or most of the site and for many or most workers, the approach chosen will 

likely result in significant underestimates of intakes. 

Tables 1 and 2 of the Boback et al. (1987) report provide stack heights and roof heights, 

respectively. It appears that the heights of the buildings are comparable to the stack heights. 

The implication is that these releases should be treated as ground-level releases for the purpose 

of atmospheric dispersion modeling, because, as a general rule, credit for elevated releases is 

only appropriate if the stack is 2.5 times higher than the nearby buildings, in which case building 

wake effects become unimportant. 

The entire approach used to derive X/Q values in the TBD could be substantially improved by 

simply using annual joint frequency data, which couples wind speed, direction, and stability 

class. This modification and the assumption of ground-level releases for deriving X/Q values 

will likely increase the doses to receptors within about 500 meters of a source, and reduce the 

doses to receptors greater than about 500 meters from a source. 

Enrichment of Emissions 

The annual emissions would tend to reflect the weighted average of the enrichment of uranium 

processed in that year. The specific activity of uranium of the enrichments handled at Fernald 

varies by more than an order of magnitude between depleted uranium and 10% enriched 

uranium. Shipment and receipts data on normal, enriched, and depleted uranium are available by 

year (e.g., Bogar 1986). These could be used to roughly assess the enrichment of emissions for 

any particular year. This does solve the problem of what enrichment to use for the enriched 

uranium production stream. However, that is an issue with broader implications for internal dose 

reconstruction, as discussed above. The research needed to more accurately assess internal dose 

in a claimant-favorable way in regard to the enrichment of the uranium being processed can also 
 

 

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be used to improve the environmental dose. SC&A notes that the question of enrichment may be 

more important for occupational internal dose than for environmental dose. 

Other Radionuclides in Emissions 

Boback et al. (1987, p. 17) discusses the sampling and analyses that were performed in 1985 to 

determine the radionuclide-to-uranium ratios in stack emissions for other radionuclides. The 

statement is made that “no information is available that would permit ratio adjustments for 

materials processed in earlier years.” This raises the question of the reliability of the ratios used 

in the TBD for the early years. That report indicates that, beginning in 1956, uranium 

concentrates from Canada were processed that contained Ra-226 (p. 19). The report states that 

the ratio of Ra-226 to U ranged from 0.037 to 10.3 μCiRa/kgU, and that, for the purpose of 

estimating Ra-226 emissions, the average ratio of 1 μCiRa/kgU was used. Pitchblende was also 

processed at Fernald from 1953 to 1955 (TBD Vol. 2, p. 54). 

The TBD does not discuss how the environmental dose from the decay products of uranium, 

notably Ra-226 and Th-230, will be estimated. NIOSH should establish a range of ratios for 

Ra-226 and Th-230 to uranium for Plant 2/3 operations, as well as any other ore-handling 

operations. Given that the Ra-226 and Th-230 content of the ores processed at Fernald varied, it 

will be important to establish a period-specific distribution of ratios of these radionuclides to 

uranium. For each period, NIOSH may wish to consider using the 95th percent confidence level 

on the mean14 of the distribution of ratios in order to provide a reasonable upper bound on the 

average ratio. It is probably not necessary to use the 95th percentile value of the full distribution 

of the ratios, since there does not appear to be any reason to believe that an individual could have 

repeatedly experienced the 95th percentile ratios. However, if it turns out that, during a given 

time period or at a given facility, the ratios were consistently at the high end of the distribution, 

then a high-end ratio may be appropriate. Some discussion and guidance regarding this 

possibility should be provided in the TBD. 

Similar comments apply to Th-232 decay products. 

5.7.3 Exposures from Diffuse Emissions 

Finding 24: Diffuse emissions of uranium and thorium may have produced significant 

internal exposures for some personnel. 

The TBD has partly addressed the diffuse emissions from the waste pits caused by wind erosion, 

but has not addressed more important sources of diffuse emissions at Fernald. As has been 

discussed, the working environment at Fernald was often very dusty. Some of the dust in the 

workplace was vented through windows or doors. There is evidence included in the TBD of 

14 It should be emphasized that the 95th percentile of the mean is a very different parameter than the 95th 

percentile of the distribution. The former should be used when the mean is the proper parameter for use in a dose 

reconstruction, but a level of assurance is needed that the mean is not underestimated. The latter is used when it is 

possible that a worker or group of workers consistently may have experienced the high end of a distribution of 

values because of uncertainties regarding where they worked and the type of work they performed, and, as a result, 

it is plausible that they in fact experienced chronic exposures to the high end of the distribution. 
 

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very high dust concentrations outdoors. For instance, the TBD documents average outdoor air 

concentrations for 1956 and 1957 from about 31 MAC to more than 130 MAC. These high dust 

concentrations were in the following work areas (TBD, Vol. 2, Table 2-14a, p. 40): 

• “Outside Williams Mill” (General Air, 44.3 MAC) 

• “Breaking Salt at outside mill” (Breathing Zone, 30.8 MAC) 

• “Shoveling onto conveyor at outside mill” (Breathing Zone, 137.80 MAC) 

• “Changing drums at outside mill” (Breathing Zone, 122.90 MAC) 

Given that these are averages over 2 years, the episodic air concentrations outdoors can be 

expected to be much higher. The environmental exposures of any unmonitored personnel 

coming in the vicinity of such high air concentrations for even modest periods of time (a few 

hours per week), even if one takes the general air sample average, may greatly exceed the 

environmental dose from stack releases. This is even more likely to be the case for the model of 

internal environmental exposures suggested. We note here that exposure to 30 MAC, even for a 

few hours, would easily result in a greater intake than any claimant-favorable model for intake 

from the diffuse emissions suggested in the TBD. Hence it is critical that evidence for diffuse 

emissions from production operations, as well as from handling and redrumming operations, be 

compiled. 

As noted already, there is evidence for large outdoor diffuse emissions of thorium, but SC&A 

has not come across quantitative data characterizing them. This is an important gap in the 

estimation of environmental exposures that NIOSH should try to plug. 

The use of a Gaussian plume model for diffuse emissions would be, of course, entirely 

inappropriate. Such exposures will have to be assessed from direct evidence of outdoor air 

concentrations in working areas during various periods of time. Air monitoring stations at the 

periphery will not be able to provide adequate data for this purpose. 

5.8 ISSUE 8: RADON 

There are two major estimates of radon emissions available that could be used as the source term 

for radon emissions from the K-65 silos (also called Silos 1 and 2). These are silos where waste 

with high radium content was stored, including waste from MCW in St. Louis, as well as waste 

generated from high-grade ore processing at Fernald. The first was estimated by Boback et al. 

(1987), which was 60 curies per year. The second was from the RAC 1995 report, which was 

part of a series of reports on Fernald commissioned by the CDC. 

Boback et al. (1987) employs conventional steady-state diffusion transport equations as codified 

into the computer code UDAD. That code was developed for use in modeling radon emanations 

from uranium mill tailings; it was applied to the silos by incorporating into the calculations 

information regarding the radiological and physical characteristics of the K-65 residues and the 

barriers to the radon emissions from the silos. The results of the Boback calculations are as 

follows: 
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(1) Radon flux from open tank = 2E5 pCi/m2-sec 

(2) Radon flux from a tank covered with 4 inches of concrete = 2400 pCi/m2-sec 

Measurements made directly above the tanks with 4 inches of concrete yielded results ranging 

from 13 to 2.8E7 pCi/m2

-sec. The Boback report states that the high values are at locations 

above areas of the dome with cracks in the concrete. However, the fact that measurements from 

these cracks are much higher than the radon flux estimated from an open tank by the model 

would leave the use of the Boback et al. estimate open to question. NIOSH chose to use the 

RAC 1995 estimate; SC&A concurs with this choice. 

The RAC report estimates the radon emissions from the silos from 1951 through 1988 to have 

been 170,000 Ci (about 4,500 curies per year), with a range of 110,000 to 230,000 Ci (5% to 

95% confidence interval) (RAC 1995, p. xii). Figure 4-1 of the TBD presents the radon releases 

from the K-65 silos. The peak of the releases was about 6,000 curies per year from 1959–1979. 

RAC 1995 acknowledges the considerable uncertainty associated with estimating radon 

emissions from the silos due to uncertainty in the diffusion coefficients. As a result, RAC 

employed a variety of models and modeling assumptions, along with Monte Carlo techniques, in 

order to characterize and quantify the magnitude of the uncertainty. Notwithstanding this 

acknowledgment by NIOSH, the TBD used the average annual emission rates to model the 

airborne radionuclide concentration, including radon, for the purpose of dose reconstruction. It 

would seem that this is not a claimant-favorable assumption. It may be more appropriate to use 

the 95th percentile values of the mean. However, since the differences between the median and 

95th percentile values are less than a factor of 2, the potential for a significant underestimate of 

the radon source term seems to be relatively small, and perhaps accounted for by the 

conservatism inherent in using a progeny equilibrium fraction of 0.7; i.e., the TBD cites evidence 

that radon progeny only achieved a 1% to 27% equilibrium, but assumed 70% equilibrium. This 

is a reasonably conservative assumption that will tend to place an upper bound on inhalation 

exposures to radon progeny, given the validity of the radon source term and atmospheric 

dispersion factors. 

Given the derived radon concentrations, exposure to radon progeny, in working level months 

(WLMs), assumes 70% equilibrium and 100 pCi corresponds to 1 WL. This is a correct 

conversion (see page 20 of the TBD). In the background information, the concept Working 

Level is defined as follows: 

...working level (WL) was introduced by Holaday et al. (1957) as a convenient 

one-parameter measure of the concentration of radon progeny in uranium mine 

air that can be employed as a measure of exposure. They define 1 WL to be any 

combination of Po-218, Pb-214, Bi-214, and Po-214 (the short-lived progeny of 

radon) in 1 liter of air under ambient temperature and pressure that results in the 

ultimate emission of 1.3e5 MeV of alpha particle energy. This is about the total 

amount of energy released over a long period of time by the short-lived daughters 

in equilibrium with 100 pCi of radon. [Schleien et al. 1998] 
 

 

 

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The TBD (Vol. 4, p. 20) indicates that exposure in WLM for thoron progeny is based on an 

equilibrium fraction of 0.1 and the assumption that 7.47 pCi of thoron corresponds to 1 WL. The 

implication is that the total alpha energy emission from the complete decay of 7.47 pCi of each 

of the short-lived progeny of thoron corresponds to 1.3E5 MeV. An independent check confirms 

that 7.47 pCi of thoron corresponds to 1.3E5 MeV of short-lived progeny. The basis for the 

assumed equilibrium fraction of 0.1 should be provided. 

Check on Radon Dose 

This section presents a hand calculation to check on a radon and progeny exposure calculation in 

the TBD. As indicated in Figure 4-1 (page 12) of the TBD, the highest median radon emission 

rate was about 6000 Ci/yr from 1958 through 1979. According to Figure 4-2 on page 14 of the 

TBD, the silos were located in grid number EA-6, and workers worked in that area about 

250 meters from the silos (see Table 4-7 on page 18). In addition, according to Table 4-8 on 

page 19, the wind blew 19% of the time from the silos toward workers at EA-6. Using 

Figures 4-3 and 4-4, the σy and σz values for stability Class F at 250 meters are about 10 m and 3 

m, respectively. For radon progeny, equation 4-3 (page 15) of the TBD is used to derive the X/Q 

value, as follows: 

X/Q = 1/(2πσyσzu) exp[-1/2(y2/σ y

 2 + H2

/σ z

 2)] 

Where: 

σy = 10 m
 

σz = 4 m
 

u = 3.2 m/s 

H = 10 m
 

X/Q = 5e-5 sec/m3 for particulates 

X/Q = 1e-4 sec/m3 for gases (radon) 

These values are in agreement with the value listed in Table 4-6 on page 18 of the TBD.15 

These are the atmospheric dispersion factors for particulate and radon emissions 250 meters 

downwind from the silos, assuming a 10-meter release height, and the wind was blowing 100% 

of the time toward the receptors at a wind speed of 3.2 m/s under stability class F. Applying a 

correction factor for wind direction of 19%, the X/Q is 9.5E-6 sec/m3

 and 1.9E-5 sec/m3 for 

radon progeny and radon, respectively. 

The radon concentration would be as follows: 

CRn = 6000 Ci/yr × 1012 pCi/Ci × 1.09E-4 sec/m3 × 0.19/3.15E7 sec/yr = 3,944 pCi/ m3
 

≈ 3.9 pCi/liter 

15 The atmospheric dispersion factors for gases are twice those for particulates due to reflection. When a 

plume containing gases, such as radon, touches down to the ground, gases “reflect” off the ground and remain 

airborne. However, when a plume containing particles touches down, the particles deposit onto the ground; hence, 

the two-fold difference in atmospheric dispersion factors for gases versus particulates. 
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This value is consistent with the values reported in Table 4-9a of the TBD. When expressed in 

terms of exposure to radon progeny with an equilibrium of 0.7, this amounts to about 0.027 WL, 

or about 0.32 WLM per year exposure. The TBD’s estimate for a similar situation and the same 

assumptions is slightly lower at 0.27 WLM per year. 

5.8.1 Environmental Radon Dose Modeling 

Finding 25: NIOSH’s modeling of radon dose is not claimant favorable and does not take 

actual working conditions into account. 

There are several ways in which the NIOSH estimates of radon dose are likely to be 

underestimated, and, hence, not claimant favorable. 

While the check on NIOSH’s calculations above yields values consistent with those in the TBD, 

SC&A is not in accordance with the NIOSH assumption that dose and dispersion coefficients 

should be calculated at a distance of 250 meters, with a release height assumption of 10 meters. 

NIOSH should use an assumption of ground-level exposures, for which the X/Q values and the 

associated exposure estimates would be 25-fold higher. Another important observation is that, at 

closer locations, the difference between the ground level and elevated X/Q values are even 

greater. For example, the closest distance analyzed in Table 4-7 is 150 meters. For this distance, 

and a ground-level release, the radon dose would be more than 4 orders of magnitude greater 

than that obtained using the NIOSH assumptions. Hence, the individuals located close to the 

silos, even if only a small part of the time, could have experienced exposures much larger than 

those reported in the TBD. 

Site expert interviews indicate that workers were in close proximity to the silos under many 

circumstances (Attachment 4); for instance, they took breaks next to the silos. There were 

attempts to control environmental radon dose, but these appear to have been instituted in the 

1990s. SC&A site expert interviews indicated the following: 

The Communication Center received real-time radon concentration data. If this 

exceeded a trigger point (100 pCi/Liter), security made an announcement asking 

individuals to stay indoors. A technician was dispatched to the area to verify the 

conditions. These announcements didn’t typically occur during the work day. 

This was a more current practice and did not occur in the 1950s, 1960s, 1970s, 

and 1980s. 

Workers also had assignments relating to the silos. In these circumstances, there were attempts 

to control the dose, but the quantification of dose in some cases appears to be difficult. For 

instance, SC&A’s interviews indicated the following: 

When individuals had to take samples or enter the silos, a glove bag was used to 

control exposure. The manhole on the top of the silo is opened and the sample is 

taken through the in and out port. There were attempts to measure radon in the 

glove bags, but these were not successful. 
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In summary, the NIOSH source term for radon appears to be claimant favorable, though there 

will remain considerable uncertainties about the actual emissions history. However, the 

modeling of the radon dose is not claimant favorable. 

5.8.2 Radon Dose from Pitchblende Ore Storage 

Finding 26: NIOSH has not considered a major source of radon dose—the storage source 

of pitchblende ore on site, near Plant 1. 

A University of Cincinnati study concluded that there was another major source of radon at 

Fernald—the Q-11 silos near Plant 1 where pitchblende ore was stored from 1952 to 1958 

(Pinney and Hornung 2006). Since this source was much closer to working areas than the K-65 

silos, it was likely a large source of exposure during the time that Q-11 ores were stored there. 

The TBD has not considered this issue. 

Pinney and Hornung (2006) also estimated the annual exposure per year due to the K-65 silos 

alone. Their estimate of mean exposure is about 1 WLM from the late 1950s to the end of the 

1970s. This is almost 4 times the estimate based on NIOSH’s assumptions. Their maximum 

estimate is about 2 WLM for most of this period, but with a peak of almost 2.5 WLM in the late 

1950s and early 1960s. Their estimates are based on assessing cumulative radon exposure from 

tracks in window glass calibrated by C-39 plastic film taped to the glass for 3 weeks. 

5.9 ISSUE 9: OCCUPATIONAL ENVIRONMENTAL DOSE – EXTERNAL 

The primary source of external environmental radiation exposures was direct radiation from 

Ra-226 and its progeny in the K-65 silos. According to the TBD, prior to 1975, the radiation 

fields were monitored with hand-held survey meters, and after 1975, external radiation exposures 

were monitored with TLDs and aerial surveys. Other contributing sources of ambient external 

radiation addressed in the TBD include the waste pits and the production facilities. 

Equation 4-5 of the TBD (Vol. 4, p. 46) presents the method used to estimate the external 

radiation dose rates at each of the 11 grid locations. The basic approach is to use the actual 

measured dose rates at the locations where measurements were made, and then derive the dose 

rates at the grid locations based on adjustments that take into consideration the distance from the 

source and the distance to the grid location using the inverse square law. One concern with this 

approach is that it only applies to point sources. For sources whose dimensions are large relative 

to the distance to the measurement location and/or the grid location, this approach could either 

significantly underestimate or overestimate the exposure rates at the grid locations. The TBD 

would benefit from a discussion of this issue. This approach, however, is not unreasonable for 

time periods when extensive survey data are available; i.e., the post-1976 period. 
 

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5.9.1 Outdoor Diffuse Emissions and External Environmental Dose 

Finding 27: The TBD does not consider outdoor diffuse emissions in production areas as a 

source of external environmental dose. 

Given the documentation regarding high diffuse emissions and high uranium and thorium 

concentrations outdoors (discussed above), it is possible that the external environmental dose, 

other than that from the K-65 silos, may have derived mainly from deposition of uranium and 

thorium dust on workers. For thorium dust, this could involve considerable deep dose as well as 

shallow dose, while for uranium it would mean mainly the latter. NIOSH should evaluate the 

extent of the problem, which may have been significant in some outdoor production areas. 

5.9.2 External Environmental Dose near the K-65 Silos 

Finding 28: External environmental dose for workers near the K-65 silos needs to be 

better evaluated. 

The TBD is silent on how external doses to workers from the silos were derived for persons that 

may have spent time in the area of Fernald containing the silos (i.e., EA-6). This is of particular 

concern for the early years before additional shielding was provided for the silos. It is also of 

concern for those unmonitored workers who may have taken breaks near the silos. For instance, 

it may especially affect female employees during the years when they were not monitored. 

5.9.3 Occupational Radon Exposure 

Finding 29: Occupational internal exposure to radon is estimated based on just two radon 

data points from 1953. This is an inadequate basis to reconstruct occupational radon dose. 

Volume 5 of the TBD describes the procedure for estimating radon dose to those workers who 

opened the K-65 waste drums and loaded Silos 1 and 2: 

From a single radon sample data sheet on which the analyses of two samples 

were recorded on 10/29/53, the higher of the two samples indicated a result of 

230 pCi/L radon gas, which verifies the logical assumption that radon gas was 

released as the drum lids were removed. In addition to the default particulate 

intake (determined as previously stated), a conservative/bounding analysis of 

possible radon plus daughter product exposures can be derived: 

• Assume 230 pCi/L (2.3 WL) with 100% daughter product equilibrium for 

1304 hrs. (163 day x 8 hr/day)/74 months of the dumping operations = 17.6 

average hours/month exposure. Then 2.3 WL 17.6/167(the fraction of a full 

working month) x 12 months = 2.9 WLM exposure per year. 

It is not clear why a measurement of 230 pCi/L would verify that it was associated with the 

opening of the drum. It is also not clear why that would be assumed to be the highest exposure 

to radon. Choosing the higher of only two samples is a rather weak basis for parameter value 
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assignment. NIOSH should better justify its assignment of radon dose to these workers or 

develop a procedure for estimating a demonstrably claimant-favorable value. 

5.10 ISSUE 10: OCCUPATIONAL MEDICAL DOSE 

5.10.1 Possible Use of Photofluorography 

Finding 30: The possible use of PFG at Fernald in the early years was ruled out in the 

TBD without adequate documentation. This is contrary to NIOSH general guidance and is 

not claimant favorable. 

The TBD states (Vol. 3, Section 3.2) that no PFG equipment was ever used at FEMP. This 

conclusion is attributed to communications with Ms. Betty Smith and Ms. Diane Jacobowski. 

Ms. Jacobowski’s statement is included as part of the Luther Brown 2002 transmittal, which is 

referenced in the TBD (Brown 2002). However, she worked from the mid-1980s onwards, and 

her opinion may therefore not be reliable for procedures relating to the 1950s. Ms. Smith was 

the only person interviewed who worked there during the period when PFG may have been used, 

but NIOSH could provide no documentation on statements by Ms. Smith. This was affirmed by 

NIOSH/ORAU during the August 18, 2006, conference call: 

ORAUT/NIOSH: There are no formal records of those conversations. They were 

just documented in the TBD and that is all there is. [Attachment 3] 

Even so, the statement by Ms. Jacobowski indicates no records on x-rays were found prior to 

1961. NIOSH should further verify that PFG units were not in use at FEMP during the period of 

1951–1958. If no positive evidence can be found that x-rays were the method used, the PFG 

should be assumed for this period. This is in accordance with the general guidance on medical 

x-rays provided in Revision 3 of ORAUT-OTIB-0006 (Kathren and Shockley 2005, pp. 20–21). 

5.10.2 X-ray Retake Rate 

Finding 31: The assumption that there was a 15% retake rate for x-rays is not adequately 

documented or analyzed. 

The TBD (Vol. 3, Section 3.2) states that a review of claimant files showed that 15% of the 

claimants reported that retakes occurred. Further review of the TBD shows that there is no 

documented attempts to establish retake rates for x-ray units in use at Fernald. During the 

conference call, NIOSH/ORAU referred to ORAUT-OTIB-0006 guidance on retake rates. That 

document states the following: 

The incidence of defective films necessitating retakes is not known, but it is likely 

to have been very small and certainly no more than a few percent and probably 

much less. [Kathren and Shockley 2005, p. 14] 

Retakes can occur either because the technician is not satisfied with the quality of the picture or 

as a result of a request by a physician. Furthermore, as SC&A noted in the conference call with 
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NIOSH ORAU, it is rare that retakes end up in the medical record. NIOSH should re-evaluate 

the potential contribution to dose that is attributable to retakes resulting from improper 

techniques or poor performance of processing equipment. 

5.10.3 X-ray Collimation 

Finding 32: The assumption that there was collimation is not technically justifiable based 

on the evidence provided in the TBD and is not claimant favorable. 

The TBD (Vol. 3, Section 3.1.4) concludes that, based upon a survey of selected radiographs 

from 1952–1980, it was determined that collimation was always used from the inception of x-ray 

use at the site. This conclusion is based upon the observation of a dark line at the bottom of the 

selected radiographs: 

...the current FEMP records manager, Mr. Brian Devir, who (as a request of the 

TBD investigation) selectively examined radiographs from chest X-rays taken 

from 1952 to 1980. He confirmed that a clearly distinct darkened area existed at 

the lower edge of each radiograph, which is specifically indicative of the use of 

collimation. Also noted was that all of the radiographs examined from the years 

1952 to 1980 exhibited the same unexposed area at the edges. A well-collimated 

beam would have left a small, unexposed area or penumbra effect at the edges 

of the radiograph, while a poorly collimated beam would have produced a 

radiograph that was exposed over the entire area. Based on the discussions with 

Mr. Devir and the correlated evaluation of the radiograph files, it is possible to 

reach the conclusion that the X-ray beams used at FEMP were collimated from 

the beginning of the medical X-ray processes at the site, and should be treated as 

such when estimating the contribution of an individual due to medical X-ray 

exposure. [TBD, Vol. 3, p. 9, emphasis added] 

Collimators are made of very dense materials (e.g., lead, etc.), and their use should appear as a 

lightened or unexposed area on the film. Also, any evidence of collimation should occur on all 

sides of the film, not just the bottom. Mr. Devir noted both of these facts in his communication 

with NIOSH (see bolded text above). Therefore, it is unclear why NIOSH concluded from this 

communication that “the darkened area at the lower edge of each radiograph” was evidence of 

collimation throughout the period in question. NIOSH should re-evaluate its conclusion. It does 

not appear to be based on the cited evidence and is not claimant favorable, in that it would 

underestimate doses relative to an assumption of no collimation. 
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5.10.4 Occupational Lumbar Spine X-rays 

Finding 33: NIOSH has prematurely concluded that lumbar spine x-rays for laborers and 

construction workers were not conditions of employment. Based on the evidence provided, 

this assumption is not sufficiently documented and is not claimant favorable. 

The TBD acknowledges that Fernald construction workers and laborers received lumbar spine 

x-rays (Vol. 3, p. 11), but NIOSH has ruled out the possibility that lumbar spine x-rays were 

used as a condition of employment at Fernald: 

It also was noted in reviewing claimant files that lumbar spine X-rays were taken 

primarily for construction worker and laborers. In a telephone communication 

with Mr. Louis C. Bogar, the former Vice President of ES&H for FEMP, on 

October 28, 2003, he clearly stated that lumbar spine X-rays and any X-rays 

other than chest were not taken as occupational or pre-employment requirements. 

A contemporaneous interview is not a sufficient basis to rule out the possibility that the lumbar 

spine x-rays were taken as a condition of employment. Such x-rays could easily have been a 

condition of employment in the 1950s and 1960s. Fernald, after all, was a site where heavy labor 

was involved for many workers, including construction workers and laborers. The TBD 

provides no evidence from claimant files or other sources that the lumbar spine x-rays that were 

done were as a result of injuries or medical conditions unrelated to employment. Unless there is 

definitive evidence that lumbar spine x-rays were unrelated to employment or were the result of 

injuries, their presence should be assumed to be a condition of employment for construction 

workers, laborers, and any others who may have received them. 
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6.0 OBSERVATIONS 

6.1.1 Internal Inconsistencies in the TBD 

Observation 1: The TBD has not been checked for internal consistency and there are 

internal contradictions in it; some of the basic facts in it are incorrect. 

Several examples of inconsistencies and factual problems have been discussed in the findings 

above. For instance, the estimate of production of 205,000 metric tons is less than the figure 

provided for RU receipts of over 246,000 metric tons. One of these numbers is wrong. There 

are two quite different estimates of RU receipts, one more that 200,000 metric tons less than the 

other. 

Another important inconsistency relates to the decontamination factor due to the use of 

respirators. Volume 2 of the TBD provides intake estimates in certain jobs with the use of 

respirators. Volume 5 of the TBD provides guidelines that do not assume the use of respirators. 

Furthermore, SC&A notes that in Table 2-1a and subsequent tables, decontamination factors are 

cited, but this is done without reference to actual respirator efficiencies or the adequacy of any 

program of fit tests. This is not relevant to dose reconstruction if the decontamination factors are 

not used, but it would be helpful if the citation of specific performance characteristics that relate 

to intake could be accompanied by a reference. 

A third example of incorrect statements relates to thorium air concentrations: 

The same air sampling procedures were followed for thorium processing as for 

uranium processing. Some records have been recovered that indicate that basic 

air activity levels were recorded in fractional MAC (70 dpm m-3 prior to 1970 and 

100 dpm m-3 thereafter) for thorium processing. The thorium air sampling results 

are similar to the uranium air sample results. [TBD Vol. 5, p. 21] 

As has been discussed in Chapter 5, there is a great deal of evidence of high thorium air 

concentrations at Fernald. 

As a final example, the production estimates in the TBD are not only internally inconsistent, they 

appear to be at variance with the materials accounting documents generated during the 

production phase of Fernald. 

SC&A discussed this issue of inconsistencies and factual problems with NIOSH/ORAU during 

the August 18, 2006, conference call. NIOSH and ORAU are cognizant of the problem and will 

correct them when a new revision of the TBD is published. It is currently under revision. 
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6.1.2 Intakes and Plant Production Capacity Utilization 

Observation 2: Individual intakes should not be linked to plant production capacity 

utilization. 

The TBD suggests that air concentrations of radioactivity for periods for which there are no data 

can be derived by reference to production capacity utilization: 

The measured airborne radioactivity concentrations are adjusted for other years 

than the year in which the measurements are made, in accordance with the 

percentage of process system throughput capacity in one shift. In absence of 

specific throughput information, Appendix 2A is used as the default model for 

FEMP production rates for the derivation of the adjustment factors. [Vol. 2, 

Table 2-3b footnote] 

The same concept is applied in Table 2-1b. A similar concept is applied to estimating in-plant 

thorium concentrations, except here, atmospheric emission ratios are used. In Table 2-1c 

(Vol. 2, p. 14), in-plant thorium concentrations were obtained by multiplying the uranium 

concentration estimates for a particular year by the thorium/uranium emission ratio. 

Air concentrations experienced by an individual worker would not be expected to vary with the 

throughput or capacity utilization, but rather with the working conditions, equipment, ventilation, 

and other industrial hygiene measures prevalent while the work is being done. It is quite 

possible for low throughput rates to have high workplace contamination and vice versa. There is 

no necessary relationship or even a tendency for throughput or capacity utilization to be related 

to air concentration. Similarly, in-plant air concentrations cannot be assumed to scale with 

emissions, as much depends on the details of the air flow patterns within the plant, the size 

distribution of the aerosol, the positions of the ventilation extraction ducts, and the degree of 

filtration imposed on the extraction. Such assumptions should not be used as a basis for intake 

estimation. The only factor related to production that can be usefully taken into account, if all 

other factors are known to be the same, is if plants were completely idle for entire shifts or 

longer. Note that this is not necessarily the same as partial capacity utilization. For instance, 

partial capacity utilization could still mean that some lathes or drills or reduction furnaces may 

be operating each day and the entire plant operated with fewer workers, creating similar 

exposure conditions to full capacity utilization, but for fewer workers. Hence, the time of 

exposure may be reduced only if there are data showing that there was no work during certain 

periods, all other things, such as industrial hygiene measures, being equal. 
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6.1.3 Bioassay Frequency and Incidents 

Observation 3: NIOSH dose reconstruction procedures should ensure that the bioassay 

samples were frequent enough to capture incidents such as chip fires, or that the plant 

procedures themselves as carried out in practice ensured that samples would be taken after 

fires or blowouts. 

Chip fires were common at Fernald. Sometimes these incidents could involve intense exposure 

to fumes, as occurred during in 1956: 

Specifically, a drum of fines located under the chip crusher ignited. By the time 

the burning drum was removed from the building (approximately 2 to 3 minutes 

later), the machining bay air was heavily laden with smoke and fume. Personnel 

did not evacuate immediately but remained in the area 7 to 8 minutes after the 

fire started. No one was observed wearing a respirator until several minutes later 

and then only a few. When evacuation was made it was for a very short duration, 

perhaps 18 minutes, and when re-entry was made the room air was still visibly 

contaminated. [Stefanac 1956] 

There was considerable contamination even after visible dust had cleared. The incident was 

analyzed to try to set procedures for such chip fires, which were frequent (refer to interviews), 

perhaps even daily in some periods. TBD does not provide any procedure to check for bioassay 

frequency, as well as who was monitored using such data on incidents and air contamination as a 

check. 

6.1.4 Uranium Isotopic Ratios 

Observation 4: The uranium isotopic ratios in some of the data in the TBD are incorrect. 

The isotopes present in uranium (U-238, U-235, and U-234) appear in certain ratios that are 

characteristic of the enrichment of the uranium. This implies certain mass ratios, which are also 

characteristic of the enrichment level. The ratios of U-238 to U-235 and U-238 to U-234 must 

be consistent with each other for a given enrichment of the sample. Some values in the TBD are 

incorrect, because they represent ratios that cannot arise in practice or are inconsistent. 

For instance, the Waste Pit 2 uranium isotopic composition is incorrect. The U-238/U-234 ratio 

suggests slightly depleted uranium (close to natural uranium), but the mass ratio of U-235/U-238 

suggests about 7% enriched uranium. Furthermore, U-235 is almost 20% of the radioactivity. 

This is impossible, since U-235 never represents more than 5% of the radioactivity at any 

enrichment of uranium. (At higher enrichments, U-234 dominates the specific activity. For DU, 

it is U-238.) 

The same problem is present in the data for Waste Pit 6 (TBD Vol. 2, p. 65) where the 

U-234/U238 ratio suggests depleted uranium, but the U-235/U238 ratio suggests enriched 

uranium. SC&A has not tried to check all such basic problems, but it is important that isotopic 

compositions be physically plausible and consistent. NIOSH should examine whether there are 

errors in the underlying data as well. 
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6.1.5 Frequency of Events in Thorium Overpacking Operations 

Observation 5: The number of “events” listed for thorium overpacking operations is very 

high, but the TBD provides no detail on the nature of most of the events, the data on which 

the estimates of event frequency and intakes were based, or how the intake estimates were 

derived. 

Table 2-22 (Vol. 2, p. 51) gives the expected number of events during thorium overpacking 

operations. It lists three specific types of events—fork impact, fork drop, physical degradation 

of the drums—and miscellaneous. For the first three, the annual event frequencies are given as 

17, 17, and 42, respectively. For miscellaneous, the event frequency is given as 1,358 per year, 

or almost 4 every day (assuming 365-day operation). The nature of these events is not specified; 

the method of estimating emissions is also not specified. This is an inordinately large frequency 

of events, whose implications for dose reconstruction need to be explored in greater detail. 

6.1.6 MDLs for Beta Extremity Monitoring 

Observation 6: The MDLs for beta extremity dosimeters should be provided for missed 

dose estimation. 

The values for the MDLs for the extremity beta dosimeters should be provided. The exchange 

frequency of the extremity dosimeters is also required to calculate the missed extremity dose. 

6.1.7 X-ray Unit Survey Data 

Observation 7: NIOSH should review the calculated data for the Bennet x-ray unit and the 

Keleket unit survey to determine if the dose estimates in Table 3-13 are appropriate. 

The TBD states that the earliest recorded survey of x-ray equipment (Keleket) occurred in 

November 1961. Review of available historical memos suggests the purpose of this survey was 

to ascertain exposures to film badges, if badges were inadvertently worn during annual chest xrays given to workers. Difficulties encountered included not being able to operate the x-ray unit 

in the full diagnostic range, and the Victoreen R-meters were not being read on the same day as 

exposures. Consequently, many assumptions were applied as being derived from NCRP 

guidelines, such as the half-value layer (HVL) of 2.5 mm Al. It appears the intent of the survey 

was to determine any undue contribution of “Grenz” radiation to skin dose, as measured on the 

film badge. NIOSH should re-evaluate the assumptions being applied; this could lead to 

substantial changes in Table 3-13 (Organ Dose Estimates to FEMP Chest Radiographs from 

1951–1977) of the TBD. 

The TBD does not detail or provide substantial evidence that equipment survey data reported for 

the period March 1977 to February 1988, as evidenced in Tables 3-10 and 3-14, are related to an 

actual survey of the output of the Bennett 300 unit, which was put into service in March 1977. 

During the August 18 conference call, NIOSH/ORAU clarified that the data for this unit are 

calculated from a Hanford unit. SC&A has requested a copy of the survey of that unit. 
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6.1.8 Miscellaneous Observations 

•	 In Table 5-6 (Vol. 5, p. 12), it is unclear why the radiation exposure limit for the 2% 

enriched soluble form is more than an order of magnitude lower than the limit for the 

natural form, whereas for the insoluble form, the limits for the natural and 2% enriched 

forms are identical at 3.0E-10. The basis of these figures should be clarified. 

•	 Table 5-8 (Vol. 5, p. 15) reports derived air concentrations from 1989; however, the table 

lists results in terms of inhalation Type S, which was not introduced by the ICRP until 

1994. A clear statement of how the original results were derived and how they 

subsequently have been interpreted would be helpful. This is of importance, as Type S 

does not correspond exactly in biokinetics to the Class Y that was formerly used. 

•	 In Figure 5.1 (Vol. 5, p. 19), should ‘Th-23’ at the top of the figure read ‘Th-228’? 

•	 In Table 5-14 (Vol. 5, p. 20), the entries for oxalate are associated with the chemical 

formula for nitrate. 

•	 On page 28, it is misleading to state that urine samples were provided after a 2-day break 

to allow elimination of uranium cleared rapidly via the GI tract. Urinalysis only 

evaluates uranium that has been taken up and subsequently excreted. What a 2-day 

interval does is ensure that the early kinetics of uptake and retention, which can be very 

variable, do not unduly influence the results obtained. 

•	 At the end of Section 5.3.4 on page 31 (Vol. 5), it is stated that uranium results that are 

within a factor of 10 of the Decision Level (DL) should be adjusted for full dose 

reconstructions. What does ‘adjusted’ mean in this context? Furthermore, it seems 

inequitable to assign a DL for Fernald at 5 times that for INEL (0.8 vs. 0.16 

micrograms/L). 

•	 As lung counting began in 1968, why does Table 5-24 (Vol. 5) show only data from 1974 

onward? In the paragraph following that table, it appears that the reference to percent 

body burden should be to percent lung burden? 

•	 On page 36, it is noted that no system performance characteristics of the Mobile In Vivo 

Radiation Monitoring Laboratory (MIVRML) have been found to date. As this was the 

Y-12 instrument, these characteristics should be in the various papers published by 

Cofield. Only one journal and one ‘grey literature’ publication are cited in the reference 

list. A more thorough search is indicated. 

•	 In Vol. 2 on page 24 in the second line of Section 2.2.4.2, ‘UF6’ should read ‘UF4.’ 

•	 Table 5-5, Vol. 5, does not contain any rating for Plant 6, where machining of U was 

done. This should be rated as high. 

•	 In Vol. 5 in Table 5-6, the heading of the second column (“mg intake = approx. 0.337 mg 

kidney – toxicity limit”) needs explanation and a better connection to the values listed in 

the column. 

•	 The energy given on page 6 of the TBD (Vol. 6) should be written as 0.300 ± 0.005 MeV. 
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•	 On page 7 of the TBD (Vol. 6), the text “Figures 6-1 and 6-2” should be changed to 

“Figures 6-3 and 6-4.” 

•	 On page 24 of the TBD (Vol. 6) the calculation of the total missed photon dose should be 

400 + 30 × 3 × 0.5 = 445 mrem and not 449 mrem as given. 

•	 Page 15 of Vol. 4 refers twice to a RAC 1988 report that does not exist. The document 

RAC 1998 that is in the reference list does not contain the information about particle 

sizes in Appendix E 

•	 In Table 6-7, Vol. 6, the values of Hp(10) and Hp(0.07) for Sr-90/Y-90 have been 

interchanged. It is probable that this also happened to these values for the other 

DOELAP energies. The table shows the “angular response,” not the “annular response.” 

Furthermore, the 9 values between the energies of M30 ± 60 V and M150± 40 H are 

given twice in the table. 
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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 

evaluating 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 the five measures of adequacy; (1) completeness of data sources, 

(2) technical accuracy, (3) adequacy of data, (4) consistency among site profiles, and 

(4) regulatory compliance. Each of these is discussed below. 

7.1.1 Objective 1: Completeness of Data Sources 

The TBD is incomplete in a number of ways. Possibly the most notable of these for the purposes 

of dose reconstruction is the incompleteness of the thorium-232 production and air concentration 

data. Therefore, the research into thorium production done by NIOSH is incomplete and 

inadequate. Much documentation indicating high dust levels of thorium was missed. Production 

periods were also missed. The thorium data in the TBD are insufficient to arrive at defensible 

estimates of thorium exposure. 

The section on “Cited References” in Volume 5 of the TBD (internal dose) does not contain any 

citations of 1950s documents for any material, including uranium. There is a section called 

“Other References,” which are presumably not cited. There are only three documents with 1950s 

dates in that section, and none of them contain thorium data. Volume 2 of the TBD, Site 

Description, where thorium is also discussed, contains no references to documents from the 

1950s. 

The temporal coverage of the data sources is also incomplete. The section on “Cited 

References” in Volume 5 of the TBD does not contain a single citation for any document from 

the 1950s for any material, including uranium. This is strange, in view of the rich documentation 

available for that period. There is a section called “Other References,” which are presumably not 

cited. There are only three documents with 1950s dates there, but none involve thorium data. 

Volume 2 of the TBD, Site Description, where thorium is also discussed, contains no references 

to documents from the 1950s. 

Recycled uranium data are incomplete and also internally inconsistent. The characterization of 

fugitive emissions is also incomplete in essential respects. As a result, some of the most 
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important sources, and possibly the most important sources, of environmental exposure have 

been missed. Original x-ray records are available. These were not checked to determine 

whether PFG was used at Fernald in the early years. Finally, the documentation of the 

interviews that were used in the TBD is also incomplete or unavailable. 

NIOSH/ORAU stated during the August 18, 2006, conference call that this was an early TBD, 

which may account for the gaps. At present, there is considerable data on NIOSH’s Site 

Research database. There is also a large archive with legal counsel who participated in the 

various Fernald-related legal proceedings. It is to be noted that some of the exhibits from 

Fernald litigation are on the NIOSH Site Research database (e.g., HSD 1954), though they are 

not cited in the TBD. These and other sources can be tapped for revising the TBD. (NIOSH has 

stated that the TBD is currently being revised.) 

7.1.2 Objective 2: Technical Accuracy 

The TBD has a number of problems with the lack of internal consistency between one volume 

and the next. There are numerous important errors in the TBD in regard to isotopic ratios of 

waste, including material that could become resuspended and inhaled. 

The model adopted for estimating environmental dose is, by and large, not appropriate for 

workers outdoors but close to buildings. Since important sources of environmental exposure, 

such as fugitive emissions in production areas, have been missed, the accuracy of the resulting 

dose reconstruction is open to question. 

Apart from chronic exposure to uranium or exposure to frequent incidents, the internal exposure 

approaches in the TBD are unlikely to result in accurate dose reconstruction results. 

The protocol for assessing finger and hand doses is inadequate. Furthermore, there are no 

correction factors for situations where workers sat astride ingots to stamp numbers on them or 

just sat on ingots at other times. A more accurate approach needs to be developed for external 

beta dose to areas other than the extremities. Finally, the issue of what data were entered into 

worker dose records in the 1983 to October 1985 period needs to be settled, since inappropriate 

correction factors were applied to TLDs during some or all of this period. 

7.1.3 Objective 3: Adequacy of Data 

The data in the TBD appear inadequate for best-estimate and bounding dose reconstruction for a 

number of situations and worker groups. Areas of particular concern include the following: 

•	 Thorium dose reconstruction 

•	 Workers exposed to raffinates, including RU-related raffinates 

•	 Workers exposed to RU 

•	 Maximum dose reconstructions for which ORAUT-OTIB-0002 is now used to provide an 

upper limit for dose 
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•	 Situations where chip fires or the machining of metal (thorium or uranium) may produce 

fumes with very small particle size 

•	 Radon exposure in the environs of Plant 2/3, and of workers who received K-65 waste 

and loaded Silos 1 and 2 

•	 Environmental dose for unmonitored workers, including women, who were not 

monitored even for external dose during 1951 to 1960 and 1969 to 1978 

NIOSH has stated that it is revising the TBD and that more data have become available, 

especially for thorium. These data have not been published (as of the end of September 2006) 

and SC&A has not reviewed them. 

If the correction factors for uranium dust that were used in the initial TLD period were actually 

entered into the dose records of workers, there would be a problem of external dose 

reconstruction during this period (1983 to October 1985). It is unclear whether this was done 

and what values were entered into worker dose records when negative doses resulted from the 

application of correction factors. 

The extent of the data available to estimate extremity doses is unclear. There was no use of 

finger badges at Fernald. The TBD guidelines suggest reliance on wrist badge records, but these 

data appear to be rather limited and may not cover the entire period of Fernald operation. 

Data on episodic releases for the early years appear to be limited. 

7.1.4 Objective 4: Consistency among Site Profiles 

The overall approach of using bioassay data, when available, for internal dose reconstruction is 

consistent with the approach in other site profiles, and with 42 CFR 82. The approach suggested 

for environmental dose reconstruction at Fernald is about the same as that for several other sites. 

The TBD proposes to use estimates of stack emissions to estimate dose to unmonitored workers. 

The procedure, which raises concerns at other, larger sites, such as the Savannah River Site, is 

even more problematic at Fernald, given the much smaller site and the many buildings on it. 

Fugitive emissions may be more important at Fernald for unmonitored workers than at very large 

sites like Hanford, Savannah River Site, or INEL. 

The approach suggested for exposure to raffinates in terms of the radionuclide lists and 

concentrations is much more defensible than the one in the MCW TBD. The use of the 

radionuclide ratios from the K-65 Silo sampling provides a sound basis for estimating intake. 

Also, the criteria for deciding which workers were actually exposed appear to be specific to 

Fernald. The screening level of “several 100 mrem” external exposure per week is rather high 

and has not been justified by comparison with other sites that handled similar materials, 

including MCW, which was the source of much of the K-65 material. 

The Fernald external TBD (Vol. 6) recognizes that a correction factor is necessary to compensate 

for the loss of information due to the low-energy photons being absorbed in the shielded filter: 
 

 

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It is estimated that a correction equal to 10% of the <250 keV values given in 

Table 6-8 be added to the Hp(10) dose due to the contribution of these low energy 

photons to penetrating dose but are absorbed in the thick filter. [TBD Vol. 6, 

p. 23] 

For comparison, the correction factor for the Nevada Test Site (NTS) is larger—25%—for the 

period 1961 to 1966. Until 1966, only gamma dose was measured. In that year, a multi-element 

dosimeter that measured shallow dose was introduced [ORAUT-TKBS-0008-6, p. 40]. 

Table 10 below compares the procedures proposed in different TBDs for different DOE sites that 

compensate for the absorption of low-energy photons in the shielded filter of the film dosimeters. 

Table 10. Correction Factors for Hp(10) Dose in Various TBDs 

Parameter FEMP NTS (1961-1966) INEEL SRS 

Compensation for loss of information Multiply the Multiply the No compensation Add the open 

of Hp(10) dose due to low-energy E < 250 keV Hp(10) by 1.25 window dose 

photons due to use of only the values by 1.1 for 30< E 250 to Hp(10) 

shielded filter to measure the Hp(10). and add to the KeV 

Hp(10) 

The differing correction factors in Table 10 are not consistently linked to the energy spectrum of 

the photons present; hence it is difficult to determine whether the approach is similar across sites 

and consistently claimant favorable. 

7.1.5 Objective 5: Regulatory Compliance 

NIOSH needs to verify that its use of ORAUT-OTIB-0002 actually represents worst-case 

assumptions relative to some conditions at Fernald, such as work with K-65 residues and other 

raffinate streams. This is important for demonstrating that its use of the efficiency procedure for 

some groups of Fernald workers conforms to 42 CFR 82. 
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8.0 REFERENCES 

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Adams W.J. 1985. Letter to Vincent Fayne, Oak Ridge Operations, DOE from NLO, Cincinnati, 

March 21, 1985 

Alvarez, J. L., S. H. Daniel, L. O. Johnson, D. E. Martz, and B. L. Rich, 1984. Radiation 

Characterization and Radiological Equipment Evaluation at the Feed Materials Production 

Center, correspondence, HS-84-033, EG&G Idaho Inc. for National Lead of Ohio, Inc, Fernald, 

Ohio, 1984. 

Bassett, A.C., W.A. Goldsmith, J.M. Googin, J.G. Crawford, and K.F. Eckerman, 1989. Health 

and Safety Provisions for Recycle Uranium Processing at the FMPC, March 7, 1989. 

Bechtel Jacobs 2000. Recycled Uranium Mass balance project Paducah Gaseous Diffusion 

Plant Site Report, BJC-PGDP-167, Final Draft, Bechtel Jacobs, June 14, 2000. 

Boback, M. W., T. A. Dugan, D. A. Flaming, R. B. Grant, and R. W. Keys, 1987. History of 

FEMP Radionuclide Discharges, FEMP-2082, Feed Materials Production Center, Fernald, Ohio, 

1987. 

Bogar 1986. L.C. Bogar to J.A. Reafsnyder, Over-all Accountability Analysis Report, Plant 

Startup through September 30, 1086, Westinghouse, December 12, 1986. Document in the 

litigation files of Waite, Schneider, Bayless, and Chesley, Cincinnati, Ohio. 

Bonfer, D.C. 1988. Thorium - A Search of Available Records at the FMPC, Westinghouse, 

November 15, 1988. 

Brown, Luther 2002. Transmittal of the FEMP X-ray Protocols Report, Fluor Fernald, Inc., May 

7, 2002. 

Clark, T.R., L. Eiikan, C.A. Hill, and B.L. Speicher, 1989. History of FMPC Radionuclide 

Emissions: Revised Estimates of Uranium and Thorium Air Emissions from 1951 to 1987, 

Addendum to FMPC-2082, Special UC-702, Westinghouse Materials Company of Ohio, 

Cincinnati, Ohio. March 1989. 

DeFazio 1965. P.G. DeFazio to S.F. Audia, Ventilation for Redrumming of Thorium Residues, 

Request for Emergency Service. National Lead of Ohio, November 17, 1965. 

del Tredici, Robert 1987. At Work in the Fields of the Bomb, Harper and Row, New York. 

DOE (U.S. Department of Energy) 2000. DOE Ohio Field Office Recycled Uranium Project 

Report, 2000. 
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DOE (U.S. Department of Energy) 2003. Recycled Uranium: United States Production 

Enricihment and Utilization, DOE/SO-0003, May 2003. 

DOE (U.S. Department of Energy) 2004. Guide to Good Practices for Occupational 

Radiological Protection in Uranium Facilities, DOE-STD-1136-2004, December 2004. 

Dolan, L.C. and C. A. Hill 1988. History of FEMP Radionuclide Discharges, Addendum to 

FEMP-2082, Special UC-11, Westinghouse Materials Company of Ohio, December 1988. 

Durkin 1953. Dr. Quigley to Charles Dees, “Industrial Case Study,” National Lead of Ohio, 

October 12, 1953. 

EPA (U.S. Environmental Protection Agency) 1999. Cancer Risk Coefficients for 

Environmental Exposure to Radionuclides, Federal Guidance Report No. 13. 

Fernald SEC Petition 2005. SEC Petition on Fernald to the Office of Compensation and 

Analysis, 2005. 

Fernald TBD 2004a. Technical Basis Document for the Fernald Environmental Management 

Project – Introduction, ORAUT-TKBS-0017-1, Vol. 1, Rev. 00, National Institute for 

Occupational Safety and Health (Kuykendall), March 17, 2004. 

Fernald TBD 2004b. Technical Basis Document for the Fernald Environmental Management 

Project – Site Description, ORAUT-TKBS-0017-2, Vol. 2, Rev. 00, National Institute for 

Occupational Safety and Health (Kuykendall), May 20, 2004. 

Fernald TBD 2004c. Technical Basis Document for the Fernald Environmental Management 

Project – Occupational Medical Dose, ORAUT-TKBS-0017-3, Vol. 3, Rev. 00, National 

Institute for Occupational Safety and Health (Kuykendall), February 11, 2004. 

Fernald TBD 2004d. Technical Basis Document for the Fernald Environmental Management 

Project – Occupational Internal Dose, ORAUT-TKBS-0017-5, Vol. 5, Rev. 00, National 

Institute for Occupational Safety and Health (Kuykendall), May 28, 2004. 

Fernald TBD 2004e. Technical Basis Document for the Fernald Environmental Management 

Project – Occupational External Dose, ORAUT-TKBS-0017-6, Vol. 6, Rev. 00, National 

Institute for Occupational Safety and Health (Kuykendall), April 20, 2004. 

Fernald TBD 2006. Technical Basis Document for the Fernald Environmental Management 

Project – Occupational Environmental Dose, ORAUT-TKBS-0017-4, Vol. 4, Rev. 01, National 

Institute for Occupational Safety and Health (Chew), February 7, 2006. 

Harris 1954. W.B. Harris to C.L. Karl, “Routine Inspection Visit to FMPC – January 1954,” 

January 27, 1954. 

Harris 1956. W.B. Harris to Merril Eisenbud, “Thorium at Fernald,” April 17, 1956. 
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Heatherton 1953. R.C. Heatherton to the Files, “Chip Furnace,” National Lead Company of 

Ohio, July 21, 1953. 

Heatherton 1953a. R.C. Heatherton to J.W. Durkin, M.D., “Occupational Histories Relating to 

Urinary Excretion Levels,” November 11, 1953. 

Heatherton 1955. R.C. Heatherton to J.A. Quigley, M.D., “Radiation from Thorium Materials,” 

National Lead Company of Ohio, April 19, 1955. 

Hinnefeld, S.L. 1988. POOS History and Risk Assessment, Westinghouse, September 19, 1988. 

Holaday, D.A., D.E. Rushing, R.D. Coleman, P.F. Woolrich, H.L. Kusnets, and W.F. Bale, 

1957. Control of Radon and Daughters in Uranium Mines and calculations of Biological 

Effects, U.S. Public Health Service Publication No. 494. U.S. Government Printing Office; 

Washingtom, DC; 1957. 

HSD (Health and Safety Division) 1954. Plant 9 air dust sample datasheet, National Lead of 

Ohio, August 5, 1954 (Marked as Plaintiffs Exhibit 766, NIOSH Site Research database number 

2783). 

ICRP (International Commission on Radiological Protection) 1982. Protection of the Worker in 

Diagnostic Radiology, Annals of the ICRP, ICRP Publication 34, Oxford, England, 1982. 

ICRP (International Commission on Radiological Protection) 2002, Supporting Guidance 3: 

Guide for the Practical Application of the ICRP Human Respiratory Tract Model, ICRP, Vol. 

32, No. 1-2, Oxford, England, 2002. 

Jones and Keim 1967. D.G. Jones and R.E. Keim to K.N. Ross, “Air Dust Evaluation of Pulling 

a Plant 4 Screw,” July 7, 1967. 

Klein 1960. F.J. Klein to R.H. Starkey, Cleaning Under Burnout Oxide Conveyor – Plant 5,” 

December 7, 1960. 

Karl [Illegible] 1955. Karl [Illegible] to [Illegible], Telegram on dust conditions and thorium 

production at National Lead, December 1955. Document Number 2808 on the NIOSH Site 

Research database. 

Kathren, R. and Shockley, V. E., 2005, Technical Information Bulletin: Dose Reconstruction 

from Occupationally Related Diagnostic X-ray Procedures, ORAUT-OTIB-0006, Rev. 03, Oak 

Ridge Associated Universities, Oak Ridge, Tennessee. December 21, 2005. 

Klevin, P.H. 1952. Ames Research Laboratory: Occupational Exposure to Thorium and 

Beryllium, July 14, 1952. 

Klevin 1954. P.B. Klevin to W.B. Harris, Health Hazards in Thorium Processing, March 5, 

1954. 
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Makhijani and Franke 1989 Addendum to the Report “Release Estimates of Radioactive and 

Non-Radioactive Materials from the Feed Materials Production Center 1951-1985, Institute for 

Energy and Environmental Research, Takoma Park, Maryland, May 1989. 

Mead 1972 J.C. Mead, History of FMPC Residue Recovery Operations, National Lead 

Company of Ohio, August 25, 1972. 

NLO (National Lead of Ohio) 1959. Sludge Furnace Alterations for Oxidation of Thorium 

Residues – Plant 6, Proposal Number CP-59-79, October 20, 1959. 

ORAUT-OCAS-001, 2002. External Dose Reconstruction Implementation Guideline, Rev. 1, 

Department of Health and Human Services, August 2002. 

ORAUT-OTIB-0002. Technical Information Bulletin – Maximum Internal Dose Estimates for 

Certain DOE Complex Claims, ORAUT-OTIB-0002, July 5, 2004. 

PACE/University of Utah 2000 Paper and Allied Chemical Workers and the Univesity of 

Utah, Exposure Assessment Project at the Paducah Gaseous Diffusion Plant, Department of 

Energy, December 2000. 

Pinney and Hornung Susan M. Pinney and Richard horning, Methods for Radon Exposure 

Estimates for Fernald Workers, University of Cincinnati, 2006; slide presentation of the study. 

Plant 9 Survey 1954 Plant 9 Survey, no author, August 16, 1954. (Marked as Plaintiffs Exhibit 

769, NIOSH Site Research Database document number 2794). 

Puncher M, J.W. Marsh, and A. Birchall, (in press). Obtaining an Unbiased Estimate of Intake 

in Routine Monitoring when the Time of Intake is Unknown. Radiat. Prot. Dosim. 

RAC, 1995, The Fernald Dosimetry Reconstruction Project, Tasks 2 and 3 Radionuclide Source 

Terms and Uncertainties, RAC Report No. CDC-5. (Radiological Assessments Corporation), 

Neeses, South Carolina, 1995. 

RAC 1998 RAC (Radiological Assessments Corporation), The Fernald Dosimetry 

Reconstruction Project, Tasks 6: Radiation Doses and Risk to residents from FMPC Operations 

from 1951-1988, Volume II Appendices, RAC Report No. 1-CDC-Fernald-1998 Final, Volume 

II, Neeses, South Carolina, 1998. 

Ross 1960. K.N. Ross to J.E. Carvitti, “Air Dust Evaluation of Thorium Furnace Operations,” 

November 14, 1960. 

Ross 1966. K.N. Ross to R.H. Starkey, “Air Dust Evaluation of Reverter – Plant 8,” February 

28, 1966 

Ross 1970. K.N. Ross to J.E. Beckelheimer, “Thorium Metal Production Housekeeping,” June 

8, 1970. 
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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. 

SC&A 2005e First Supplemental Review of the Bethlehem Steel, Site Profile, ORAUT-TKBS0001, Draft Rev. 2, September 2005. 

SC&A 2006 SC&A Draft Review of the Special Exposure Cohort (SEC) Petition Evaluation 

Report for Y-12, Dated April 7, 2006, April 19, 2006. 

Schleien, Bernard, Lester A. Slaback, Jr., and Brian Kent Birky, Eds. 1988. Handbook of 

Health Physics and Radiological Health, Third Edition. Williams & Wilkins, A Waverly 

Company, 1998. 

Spenceley, R.M. 1985. Joint Task Force on Recycle Material Processing, April 29, 1985, with 

Attachments. NIOSH Site Research database document number 4301. 

Starkey 1963. R. H. Starkey to C. R. Chapman, “Air Dust Re-Evaluation of the Thorium 

Furnace – Plant 6,” National Lead Company of Ohio, March 26, 1963. 

Starkey 1968. R. H. Starkey to C. R. Chapman, “Problems Associated with Thorium Processing 

– Plant 8,” National Lead Company of Ohio, October 1, 1968. 

Stefanac 1956 A.J. Stefanac to C.E. Schumman, “Uranium Fire in Machining Area, Plant 6,” 

December 6, 1956. 

Strom, D.J. 2003. Eliminating bias in routine bioassay when there is an unknown time of intake. 

Radiat. Prot. Dosim. 105(1-4), pp. 339-340, 2003. 

Westinghouse 1986 Feed Materials Production Center Final Phase-In Report: Environment, 

Safety & Health, Volume 4 of 15, Westinghouse Materials Company of Ohio, January 17, 1986. 

Wunder 1955 G.W. Wunder to C.L. Karl, “Decontamination of Gloves,” National Lead, 1955 

(no date on the letter, but it is mid-1955). 
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ATTACHMENT 1: SC&A QUESTIONS ON THE FERNALD TBD SENT 

TO NIOSH 

QUESTIONS FOR NIOSH REGARDING THE TECHNICAL BASIS DOCUMENT FOR 

THE FERNALD ENVIRONMENTAL MANAGEMENT PROJECT 

(FEED MATERIALS PRODUCTION CENTER) 

A. GENERAL QUESTIONS AND QUESTIONS RELATING TO VOLUMES 1 AND 2 

OF THE TBD 

1.	 Could NIOSH provide SC&A with the notes of its interviews with site experts? 

2.	 NIOSH states that there were a “relatively small number of production workers” at 

Fernald (TBD, Vol. 1, p. 8). What is the documentary basis for this statement? In the 

same paragraph, the TBD states that “it seems likely that few workers routinely 

exceeded established exposure limits.” What is the documentary basis for this 

statement? 

3.	 The TBD provides cumulative production figures of nearly 170,000 metric tons of 

uranium metal and 35,000 metric tons of intermediate products (Vol. 1, p. 5). Please 

provide the reference(s) for these figures. 

4.	 Was the ore processing flowsheet similar to that used at Mallinckrodt with the various 

stages of filtering and concentration of Ra-226, Th-230, Pa-231 and Ac-227? 

5.	 Would the ratios of radionuclides in the K-65 Silo 1 or Silo 2 be applicable to specific 

waste streams, or do they represent mixtures of actual waste streams that were all 

discharged into the silos? The question relates only to Fernald waste streams and not 

the Mallinckrodt materials in the silos. 

6.	 What is the scientific justification for using the ratio of Th-232 to U atmospheric 

emissions to determine in-Plant thorium contamination? 

B. QUESTIONS RELATING TO MEDICAL DOSE (VOL. 3) 

1.	 On page 11 of Vol. 3, NIOSH cites a number of telephone communications on the basis 

of which the possible use of PFG at Fernald was ruled out. Could NIOSH provide 

SC&A with the records of these communications? 

2.	 The TBD does not detail the evidence that equipment survey data reported for the 

period March 1977 to February 1988, as shown in Tables 3-10 and 3-14, are related to 

an actual survey of the output of the Bennett 300 unit, which was put into service in 

March 1977. Could NIOSH clarify whether the data are from an actual survey? 

3.	 Section 3.1.4 of the TBD concludes that, based upon a survey of selected radiographs 

from 1952–1980, it was determined that collimation was always used from the 
 

 

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inception of x-ray use at the site. This conclusion is based upon the observation of a 

dark line at the bottom of the selected radiographs. Since collimators are made of very 

dense materials (e.g., lead, etc.), their use should appear as a lightened or unexposed 

area on the film. Also, any evidence of collimation should occur on all sides of the 

film, not just the bottom. Did NIOSH examine other explanations for the black line at 

the bottom of the radiographs? 

4.	 Are doses from x-rays taken after workplace accidents going to be included in dose 

reconstructions? 

5.	 The TBD in Section 3.2 states that a review of claimant files showed that 15% of the 

claimants reported that retakes occurred. Could NIOSH provide SC&A with the data 

compilation used to determine the retake rate? 

C. QUESTIONS RELATING TO ENVIRONMENTAL DOSE (VOL. 4) 

1.	 Why did the TBD use the source term developed by Boback 1987 and the 1988 

supplement for uranium, rather than the source term developed for the Radiological 

Assessments Corporation by the CDC, which is much higher (about 310,000 kilograms 

compared to about 175,000 kilograms used by NIOSH)? Did NIOSH take into account 

the consideration that the RAC source term has been shown to be in accordance with 

soil data in Appendix C (RAC, 1998)?16 

2.	 Why did the TBD use the thorium source term from Boback 1987 and the 1988 

supplement rather than the RAC 1995 source term?
 

3.	 Table 4-4 lists annual airborne thorium emissions at Plants 8 and 9 and the Pilot Plant. 

This estimate is claimed to be conservative because of the assumptions used for 

scrubber and dust collector efficiency. What were the values of efficiency used? Did 

the procedure take into account documentation indicating that scrubber efficiency, 

notably in Plant 8, was sometimes far below the manufacturer-specified range? 

4.	 According to a tabulation by NLO,17

 a significant fraction of the uranium releases from 

Fernald were of an episodic or accidental nature, influencing the environmental doses. 

How is NIOSH going to account for episodic releases in estimating environmental 

internal dose for individual dose reconstructions? 

5.	 Tables 4-2 and 4-3 (TBD, Vol. 4) summarize annual fugitive uranium and thorium 

emissions. Please provide methodological details as to how the numbers were derived. 

6.	 Could information be provided that demonstrates that the trace radionuclide-to-uranium 

ratios observed in 1985 apply to the earlier years? Specifically, what about the 

16 RAC (Radiological Assessments Corporation), 1998, The Fernald Dosimetry Reconstruction Project, 

Task 6 Radiation Doses and Risk to Residents from FMPC Operations from 1951-1988, RAC Report No. 1-CDCFernald-1998-FINAL Vols. I and II. 17 Adams W.J. (1985), letter to Vincent Fayne, Oak Ridge Operations, Cincinnati, March 21, 1985. 
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radionuclide ratios for (a) ore processing, including pitchblende processing, and 

(b) waste stream handling, processing, and dumping? 

7.	 In developing the radionuclide-to-uranium ratios, the TBD used average observed 

values. Has NIOSH considered using the 95th percent confidence level of the mean, as 

opposed to the true mean, as a more claimant-favorable strategy? 

8.	 Are there time periods when a given facility may have experienced radionuclide-touranium ratios that were chronically at the high end of the distributions? 

9.	 Given that Tables 1 and 2 of the Boback report cited in the TBD reveal that the release 

heights were comparable to the heights of the nearby buildings, what is the basis for 

taking credit for an elevated release of 10 m when deriving atmospheric dispersion 

factors? How were building wake effects taken into consideration? 

10.	 For the purpose of deriving the radon and radon progeny releases from the silos, the 

TBD used the median values derived in the RAC 1995 report. Wouldn’t this approach 

be considered claimant-neutral as opposed to claimant-favorable? 

11.	 Page 17 of the TBD states that atmospheric dispersion factors (X/Q values) were 

derived assuming a wind speed of 3.2 m/sec and stability class F. Once the X/Q values 

were derived for a given distance between the release point and receptor (using the σy 

and sigma σz values in Figures 4-3 and 4-4 of the TBD), an adjustment factor is applied 

to account for the frequency the wind blows toward a given receptor from a given 

source. Why didn’t NIOSH employ the conventional joint frequency approach to 

deriving average annual atmospheric dispersion factors? Furthermore, the selected 

wind speed of 3.2 m/s does not appear to be claimant favorable. Please provide a 

justification as to why NIOSH is using this value for wind speed. 

12.	 Table 4-8 contains the estimated distances for receptors from contributing emission 

sources. For EA-6, the distance from the K-65 silos is given as 250 m, even though the 

geographic center of EA-6 appears to be at a distance of about 100 m. The distance 

from the K-65 silos to EA-9 is given as 2,000 m, even though the most distant point in 

EA-9 appears to be about 1,500 m away from the K-65 silos. The distance to Plant 7 to 

EA-3 and EA-8 is 250 m in both cases, even though Plant 7 is located inside EA-7. 

Please explain the basis for the assumptions. 

13.	 The TBD states on page 16 that the respirable fraction (<10 μm) of uranium particles 

was determined to be 65% on the basis of RAC (1995), Table E-1. It appears that for 

this calculation, the simple arithmetic average of data from 15 dust collector stacks was 

used. Table E-1 does not provide data on particle sizes from scrubber emissions (Plant 

2/3 and Plant 8). Table E-8 of RAC (1995) indicates that the composite of U3O8 

releases indicate that more than 75% of the emissions in the outlet had a particle size of 

less than 10μm. Please explain how the fraction of 65% respirable particles is 

representative for the total of all uranium emissions. 
 

 

 

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14. Has NIOSH considered the contribution to the internal dose associated with the 

resuspension and inhalation of deposited Pb-210? 

15.	 Has NIOSH attempted to compare the pre-1989 derived atmospheric dispersion factors 

with the actual empirically determined atmospheric dispersion factors obtained using 

the actual monitored emissions and airborne radionuclide concentrations at monitored 

locations? 

16.	 The footnote to Table 4-7 on page 19 suggests that the dispersion coefficients were 

multiplied by a factor of 0.5 for U and Th particulate aerosols, presumably to account 

for plume depletion, as explained in the paragraph below equation 4-3 on page 17. For 

most distances, plume depletion will be less than 50%. Please explain how it can be 

claimant favorable to apply a uniform plume depletion factor of 50% for all releases of 

particulates. 

17.	 Equation 4-5 on page 35 of the TBD presents the method used to estimate the external 

radiation dose rates at each of the 11 grid locations. The basic approach was to use the 

actual measured dose rate at the locations where measurements were made, and then 

derive the dose rate at the grid locations, based on adjustments that take into 

consideration the distance from the source and the distance to the grid location using 

the inverse square law. One concern with this approach is that it only applies to point 

sources. Has NIOSH evaluated the degree to which this approach works for sources 

whose dimensions are large relative to the distance to the measurement location and/or 

the grid location? 

18.	 For the purpose of deriving the external environmental exposure pre-1976, when there 

were no measurements, the doses were derived by comparing the uranium throughput 

in those years with the years for which there were external environmental dose 

measurements. What is the relevance of uranium production to external environmental 

dose in outdoor areas? Why did NIOSH not use uranium emissions instead, for 

instance? Were uranium isotopes the main external environmental dose problem 

throughout the Fernald site? Has NIOSH evaluated the degree to which the controlling 

factors remained unchanged over the years? 

19.	 The TBD does not discuss the methods used to derive pre-1976 external environmental 

doses from the silos. How does NIOSH plan to reconstruct these doses? 

20.	 How does NIOSH propose to reconstruct doses for the K-65 workers involved in 

handling Mallinckrodt K-65 residues, including the unloading of these residues and 

their loading into Silo 1? 

D. QUESTIONS RELATING TO INTERNAL DOSE (VOL. 5) 

1.	 What is the reference for the decontamination factor of 50 used for some Th-232 

production activities? 
 

 

 

 

 

 

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2.	 Table 2-1a assumes respirator-based decontamination by a factor of 50 for some 

operations (Vol. 2, pp. 12–13). But in Vol. 5, “at least a factor of 10” is given for 

decontamination, and it is said that respirator use was not consistent and a 

decontamination factor cannot be assumed (Vol. 5. pp. 22–23). Is a decontamination 

factor being assumed for uranium when air concentrations are used for intake 

estimation? If so, for which jobs and periods? And what is the value being used? 

3.	 Has NIOSH taken into account the dose reconstruction implications of the finding that 

respirators were judged at one point (1953) to be the “epitome of filth?”18 

Specifically, if respirators were stored in places or were worn so that they were 

susceptible to contamination on the inside, the intake could possibly be even higher 

than for those who did not wear respirators. Has NIOSH done interviews regarding 

jobs and periods during which respirators were worn and on the condition of the 

respirators? If so, SC&A requests the records of these interviews. Has NIOSH 

determined whether a central service (recommended in the memo quoted in the 

footnote) was implemented, and if so, when? 

4.	 On page 11 (TBD, Vol. 2), it is not clear why thoria gel production for 1964 and 1965 

was estimated based on a linear extrapolation of the quantity produced in 1966 through 

1970. Can some justification for this assumption be provided? 

5.	 Could NIOSH provide the flowchart of thorium processing? Was it similar to the 

Ames Laboratory flowchart? 

6.	 How has NIOSH taken into account localized high concentrations of uranium dust in 

areas such as dust collector baghouses? 

7.	 Is NIOSH developing an internal dose co-worker model? If so, what periods would this 

apply to, and what data are being used? 

8.	 Has NIOSH compiled internal dose data into a database? If so, could it be made 

accessible on the Advisory Board’s section of the O Drive? 

9.	 How is NIOSH going to reconstruct internal dose prior to 1953, since there do not 

appear to be data before 1953, as implied by the sentence, “A urinalysis program was 

administered at FEMP starting in 1953 or possibly before” (p. 30 of Vol. 5). The table 

on the same page states that there are uranium bioassay data for 1952. Are there data 

for 1952? 

18 Dr. Quigley to Charles Dees, “Industrial Case Study,” October 12, 1953, p. 3, on which Dr. J. W. Durkin 

appears to be quoted. The full quote, which has the name of one person (perhaps two) deleted from the document is 

as follows: “The other problem that became apparent in this situation is the poor care being given to the dust 

respirators. The ones observed by [blank] and myself near the Chip Burner were the epitome of filth. Apart from 

this, it would have been a perfect fomite [?] for the transfer of respiratory infection between employees. This simply 

corroborates the reiteration of [blank] that something should be done about the respirator situation – either the men 

must take better care of them, or central service must be provided.” An earlier part of the document notes that “there 

were two Dust-Foe respirators hanging on hooks” in the “shack-type office in the [Chip Burner] area.” 
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10.	 Since no bioassay data for thorium are available prior to 1990 – that is for the entire 

production period – how is NIOSH going to validate the dose estimates for 

thorium-232, as well as for its decay products, notably radium-224? 

11.	 Since much of the thorium data is lost and many documents have apparently been 

destroyed (p. 18, Vol. 5), and since there are hardly any bioassay data or other data 

specific to thorium in the workplace, how is NIOSH going to ensure that the dose 

reconstructions are claimant favorable? How is NIOSH going to ensure that all plants 

where thorium was processed are included in its list? Could NIOSH provide all the 

interviews on which its analysis of thorium production and related issues is based? 

12.	 Given that thorium-232 DCFs are orders of magnitude larger than uranium for some 

organs, how is NIOSH going to address doses to uranium workers in the plants listed 

for thorium production (Plants 8 and 9, the Pilot Plant, and possibly Plant 4) (a) during 

thorium production periods, and (b) due to resuspension of thorium dust during nonthorium production periods? 

13.	 Could NIOSH provide the records that have been recovered in relation to thorium 

described at the bottom of page 21, Vol. 5? 

14.	 On page 22, Vol. 5, NIOSH states that “Therefore, the three Plants mentioned [Plants 8 

and 9, and the Pilot Plant] should be considered the primary processing sites, although 

there is some evidence that a few isolated thorium operations occurred in other 

locations.” There seems to be no guidance for dose reconstruction at these other 

locations (such as Plant 4), and how the periods or workers who were exposed would 

be determined. How is NIOSH addressing the issue of thorium work in Plants other 

than Plant 8, Plant 9, and the Pilot Plant? 

15.	 On page 22, NIOSH states that it is using BZ samples from lapel samplers to 

conservatively estimate thorium exposures. How is NIOSH taking into account the 

Y-12 study indicating that this is not a reliable way to make intake estimates, and that 

BZ-estimated intakes could be significant underestimates when compared with bioassay 

estimated intakes? 

16.	 Since enrichments of uranium-235 up to 20% were processed at Fernald, how does 

NIOSH justify the use of 2% enrichment as the default value after 1964? Given the 

large difference in specific activities and the fact that the fluorometric method was used 

for determining uranium content of urine, this would appear to be an assumption that 

would not be claimant favorable for some groups of workers at some times. Would it 

be possible to use a range of enrichments with a suitable distribution (or distributions 

for different time periods) instead? 

17.	 In Table 5-11, RU contaminant concentrations are given for plutonium-239, 

neptunium-237 and technetium-99. Although plutonium-239 is likely to have 

dominated the plutonium component of the contamination in mass terms, 

plutonium-238 could have been more important in activity terms. Has NIOSH given 
 

 

 

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consideration to the possibility of specifying a default mass concentration for 

plutonium, together with a default partitioning between plutonium-238, plutonium-239, 

and plutonium-240, to allow intakes of activity by radionuclide to be assigned? 

18.	 In Table 5-16, is there any explanation why Pb-210 and Po-210 activity concentrations 

in Silo 1 measured in 1993 are substantially less than would be expected based on the 

secular equilibrium concentrations that would be supported by the Ra-226 present? It is 

noted that this effect is much less marked in Silo 2. 

19.	 How can the Rn-222 concentration of 2.3 WL given on page 27 of Volume 5 be 

justified as claimant favorable when it is based on the higher of only two samples from 

a single radon sample data sheet? 

E. QUESTIONS RELATING TO EXTERNAL DOSE (VOL. 6) 

1.	 Is NIOSH developing an external dose co-worker model? If so, what periods would 

this apply to and what data are being used? 

2.	 Page 23 of the external dose volume mentions the use of co-worker data for missed 

doses? What criteria are being used to choose the co-workers for the missed doses? 

3.	 Page 23 also mentions lost dosimeter results. What proportion of the data has been 

lost? 

4.	 Has NIOSH compiled external dose data into a database? If so, could it be made 

accessible on the Advisory Board’s section of the O Drive? 

5.	 The TBD discusses adjustments to dosimeter readings. In regard to radioactive dust 

settling on the dosimeter, the TBD states that dosimeters were in plastic bags “at times” 

(p. 11, Vol. 6).19

 However, Volume 4 of the set of transition reports in the handover 

from NLO to Westinghouse discusses the application of adjustment factors to TLDs for 

a period between 1983 and October 1985. The use of this correction factor sometimes 

resulted in negative radiation dose estimates. The correction factors resulted in changes 

(according to the calculations shown in the datasheets) of 6% to 663%. In the examples 

given in the report, the largest magnitude correction of 1,652 millirem was applied to a 

dose of 1,291 millirem, resulting in a net negative estimated dose equal to -361 mrem.20 

The practice was used from 1983 (when TLDs were introduced) to October 1985, when 

its regular use was discontinued. However, it appears to have been continued in an 

19 “An additional radiological concern at several locations at FEMP occurred when workers were subjected 

to high levels of radioactive material-bearing dust. This widespread source of contamination was a concern for 

personal dosimeters, so at times the dosimeters were enclosed in plastic bags for protection against dust 

contamination. The manner in which these contaminated dosimeters were handled was not identified; however, this 

should not be an issue in dose reconstruction because the dosimeters were calibrated in plastic bags and no 

adjustments were made to the dosimeter results for either Hs(0.07) or Hp(10).” (TBD, Vol. 6, p. 11) 20 Feed Materials Production Center, Final Phase-in Report, Vol. 4 of 15, Environment, Safety and Health, 

Westinghouse Company of Ohio, January 17, 1986. See Attachment 3 for the datasheets. 
 

 

 

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ad hoc fashion after that date.21 While doses with high percentage corrections (more 

than 50%, therefore including negative dose estimates) were not automatically entered 

into the dose record, it is unclear what exactly was done. The TBD does not discuss 

this problem, although it indicates some difficulties in the initial period of TLD testing 

due to a problem in the algorithm, notably for shallow dose (p. 12, Vol. 6). Has 

NIOSH investigated this problem and how the resultant doses might be interpreted? 

Since the TBD acknowledges that plastic bags were used only “at times,” has NIOSH 

investigated the periods when this was not the practice? Were correction factors 

applied during such periods? Does NIOSH have documentation indicating the periods 

when dosimeters were in plastic bags? Section 6.5 on adjustments to dose does not 

discuss the use of the correction factors described above. How is NIOSH going to take 

them into account? 

6.	 Vol. 6 of the TBD discusses correction factors for geometry. Has NIOSH taken 

adequate account of some jobs where the badge readings were unlikely to have any 

systematic relationship to the organ dose? One such job, stamping numbers on ingots, 

was photographed by Robert del Tredici in 1987. The photograph shows the worker 

sitting astride an ingot stamping an ID number on its flat face; it can be provided upon 

request. His film badge is dangling from his coverall pocket parallel to the face of the 

ingot. His body shields the radiation from behind. The use of wrist badges is evident. 

The angular response correction factors (Table 6-7) do not address this problem. 

7.	 On page 22 of Vol. 6, NIOSH states that “Corrections to the FEMP-reported dose are 

required, due to uncertainties in the recorded data and lack of significant data, 

especially prior to 1980.” How much pre-1980 data is missing? What happened to the 

individual external dose records for the pre-1980 period that caused a significant 

amount of data to be missing? 

21 Ibid. p. 15. 
 

 

 

 

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ATTACHMENT 2: ANSWERS TO SC&A QUESTIONS ON 

FERNALD SITE PROFILE 

FINAL ORAUT DRAFT 

08/16/2006 

A. GENERAL QUESTIONS AND QUESTIONS RELATING TO VOLUMES 1 AND 2 OF THE 

TBD 

1. Could NIOSH provide SC&A with the notes of its interviews with site experts? 

The Site Profile development team only interviewed four former Fernald workers. Unfortunately, 

there were no comments from interviewees that related directly to issues or assumptions in the 

TBDs, so documentation of these interviews was not retained. 

2. NIOSH states that there were a “relatively small number of production workers” at Fernald (TBD, 

Vol. 1, p. 8). What is the documentary basis for this statement? In the same paragraph, the TBD 

states that “it seems likely that few workers routinely exceeded established exposure limits.” What is 

the documentary basis for this statement? 

ASI (Advanced Sciences Inc.) prepared a document (date unknown) for Westinghouse Materials 

Company of Ohio (Fernald, Ohio) which states that there were almost 2900 employees, some of 

whom were production workers. This is relatively small when compared to other AEC sites such 

as Hanford and SRP. 

The basis for stating that it seems likely that few workers routinely exceeded established exposure 

limits is the many letters and notes [Dugan (1981) and Noyes (1968)], as well as lists of 

individual exposure results in the early production years. 

3. The TBD provides cumulative production figures of nearly 170,000 metric tons of uranium metal and 

35,000 metric tons of intermediate products (Vol. 1, p. 5). Please provide the reference(s) for these 

figures. 

The original figures were calculated and extrapolated from available data. Other data was 

received from mass balance reports. The site descriptions and other TDB sections will be revised 

to reflect updated information, which will include references for the information. 

4. Was the ore processing flowsheet similar to that used at Mallinckrodt with the various stages of 

filtering and concentration of Ra-226, Th-230, Pa-231 and Ac-227? 

The two facilities' flow sheets have not been reviewed together. We currently understand that 

there were similarities with the Mallinckrodt Destrehan process, but the process adopted at 

Fernald would have included modifications and upgrades. 

5. Would the ratios of radionuclides in the K-65 Silo 1 or Silo 2 be applicable to specific waste streams, 

or do they represent mixtures of actual waste streams that were all discharged into the silos? The 

question relates only to Fernald waste streams and not the Mallinckrodt materials in the silos. 
 

 

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The isotopic ratios were determined in the early 90s by taking core sample of the accumulated 

sludge. Thus the analyses represent results of mixtures of actual waste streams that were 

discharged to the silos, including the Mallinckrodt waste. 

6. What is the scientific justification for using the ratio of Th-232 to U atmospheric emissions to 

determine in-Plant thorium contamination? 

The footnote to Table 2-1c indicates that the basis for the ratios would be found in Appendix 2B, 

but it appears that there is a typographical error somewhere. We will either provide the basis for 

these numbers or delete them, as they are superseded by information in the internal dose TBD. 

B. QUESTIONS RELATING TO MEDICAL DOSE (VOL. 3) 

1. On page 11 of Vol. 3, NIOSH cites a number of telephone communications on the basis of which the 

possible use of PFG at Fernald was ruled out. Could NIOSH provide SC&A with the records of these 

communications? 

No other information regarding telephone conversations beyond that included in the TBD, is 

available. 

2. The TBD does not detail the evidence that equipment survey data reported for the period March 1977 

to February 1988, as shown in Tables 3-10 and 3-14, are related to an actual survey of the output of 

the Bennett 300 unit, which was put into service in March 1977. Could NIOSH clarify whether the 

data are from an actual survey? 

It appears the data for the Bennett unit were calculated, not measured. The exposure data 

reported in a memo dated February 24, 1977, presumably associated with the Bennett X-ray 

machine, were not measurement data. Instead they represented calculations of exposure for 

various projections based on the nominal technique (including tube potential and mAs) in use at 

Fernald at that time and nominal dose factors extracted from a graph on page 159 of the 

Radiological Health Handbook. The dose factors, in units of mR per mAs, were selected to match 

the tube potential and Source to Skin Distance for the projection of interest. The footnote below 

Table 3-10 which refers to the “the measured data from 02/77” [emphasis added] is an error, 

and will be changed in the next revision. 

3. Section 3.1.4 of the TBD concludes that, based upon a survey of selected radiographs from 1952– 

1980, it was determined that collimation was always used from the inception of x-ray use at the site. 

This conclusion is based upon the observation of a dark line at the bottom of the selected radiographs. 

Since collimators are made of very dense materials (e.g., lead, etc.), their use should appear as a 

lightened or unexposed area on the film. Also, any evidence of collimation should occur on all sides 

of the film, not just the bottom. Did NIOSH examine other explanations for the black line at the 

bottom of the radiographs? 

No other information is available other than that presented. The fact that evidence of visible 

collimation is not seen on all edges of the film does not mean that collimation is not applied. 

Preparing to expose a radiograph includes an attempt to “cut the four corners” and precisely 

align the film and x-ray beam boundary. See SRDB Ref ID 22720 for a documented 

communication with a Brookhaven National Laboratory X-ray technician who used that 

technique. However, the ORAUT will attempt to look at actual radiographs from Fernald again 

to resolve the question about the "black line". 
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4. Are doses from x-rays taken after workplace accidents going to be included in dose reconstructions? 

In accordance with 42CFR 81 and 82, only medical exposures that were performed for medical 

screening and required as a condition of employment are included in the occupational medical 

dose. Diagnostic and therapeutic procedures not required for medical screening are not 

included.” X-rays taken after workplace accidents are diagnostic and so are not included in dose 

reconstruction. 

5. The TBD in Section 3.2 states that a review of claimant files showed that 15% of the claimants 

reported that retakes occurred. Could NIOSH provide SC&A with the data compilation used to 

determine the retake rate? 

No other information regarding X-ray retake rate, beyond that included in the TBD, is available. 

C. QUESTIONS RELATING TO ENVIRONMENTAL DOSE (VOL. 4) 

1. Why did the TBD use the source term developed by Boback 1987 and the 1988 supplement for 

uranium, rather than the source term developed for the Radiological Assessments Corporation by the 

CDC, which is much higher (about 310,000 kg compared to about 175,000 kg used by NIOSH)? Did 

NIOSH take into account the consideration that the RAC source term has been shown to be in 

accordance with soil data in Appendix C (RAC, 1998)? 

The original revision of the Fernald Occupational Environmental Dosimetry Technical Basis 

Document (OEDTBD) used the Boback data to estimate exposure to site releases because it was 

believed that its use would be sufficiently conservative and the resulting exposures would 

represent exposure estimates that would be favorable to the claimant. Use of the release data 

compiled by RAC (1995) would simply add to the existing conservative estimate. 

2. Why did the TBD use the Th source term from Boback 1987 and the 1988 supplement rather than the 

RAC 1995 source term? 

See response to C.1 above. 

3. Table 4-4 lists annual airborne Th emissions at Plant 8 and 9 and the Pilot Plant. This estimate is 

claimed to be conservative because of the assumptions used for scrubber and dust collector efficiency. 

What were the values of efficiency used? Did the procedure take into account documentation 

indicating that scrubber efficiency, notable in Plant 8, was sometimes far below the manufacturerspecified range? 

For the Th emission calculations, the efficiency assumed for the scrubber was 85% and the 

efficiency assumed for the dust collector was 95% (Dolan and Hill 1988), and although Dolan 

and Hill were aware that efficiencies varied, they thought their chosen values compared 

reasonably to the NRC’s 95% estimate for a venturi-type scrubber and the typical rating of 99%+ 

for dust collectors, as well as made allowances for “operational upset.” 

The RAC 1995 document provides a description of the scrubber efficiencies at both Plants 2/3 

and 8 that differs from the Dolan and Hill (1988) assumptions. Updates to the TBD are 

warranted based on the differences in the efficiency estimates. 
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4. According to a tabulation by NLO, a significant fraction of the U releases from Fernald were of an 

episodic or accidental nature, influencing the environmental doses. How is NIOSH going to account 

for episodic releases in estimating environmental internal dose for individual dose reconstructions? 

Episodic (and operational) stack releases are included as annual integrated emissions within the 

tables in the TBD. Over extended periods of time, these integrated emissions provide means of 

estimating internal exposures for individuals who were not monitored and who would not have 

required monitoring because of their low potential for exposure during their employment. In 

accordance with program guidance given in ORAUT-PROC-0031, the derived maximum sitewide annual median intakes via inhalation and ingestion will be used to estimate doses for these 

unmonitored individuals when other dose-estimating information is not available. 

5. Tables 4-2 and 4-3 (TBD, Vol. 4) summarize annual fugitive U and Th emissions. Please provide 

methodological details as to how the numbers were derived. 

For fugitive emissions, EPA guidelines were used to calculate emissions from the waste storage 

and production areas. Reference: Method for Estimating Fugitive Particulate Emissions From 

Hazardous Waste Sites. U. S. Environmental Protection Agency, Cincinnati, Ohio, August 1987. 

EP/600/2-87/066 PB87-232203. 

6. Could information be provided that demonstrates that the trace radionuclide-to-U ratios observed in 

1985 apply to the earlier years? Specifically, what about the radionuclide ratios for (a) ore processing, 

including pitchblende processing, and (b) waste stream handling, processing, and dumping? 

Yes. The values represent the earlier years. These values are also given within the Fernald 

Internal Dosimetry Technical Basis Document. 

7. In developing the radionuclide-to-U ratios, the TBD used average observed values. Has NIOSH 

considered using the 95th percent confidence level of the mean, as opposed to the true mean, as a 

more claimant –favorable strategy? 

Use of the mean values is reasonable for estimates of exposures to unmonitored workers, unless 

there is additional information that indicates that other values should be used. The mean ratios 

are to be applied to the maximum annual median uranium values, so they would tend to be 

favorable to claimants. 

8. Are there time periods when a given facility may have experienced radionuclide-to-U ratios that were 

chronically at the high end of the distributions? 

Ratios of uranium to other radioactive contaminants varied among plants and even among areas 

within plants due to operational conditions and/or chemical processes being conducted. It would 

be expected that the non-uranium radionuclide to uranium ratios would be much larger in plants 

1, 2/3, and 4; but becoming more weighted to uranium after initial reduction of UF4 into metal 

within the Plant 5 “A” area. 

9. Given that Tables 1 and 2 of the Boback report cited in the TBD reveal that the release heights were 

comparable to the heights of the nearby buildings, what is the basis for taking credit for an elevated 

release of 10 m when deriving atmospheric dispersion factors? How were building wake effects 

taken into consideration? 
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Many of the stack heights given in Table 1 indicate that they are only a few feet above the roof 

peak heights provided in Table 2 of Boback et al (1987), however the previous calculations need 

to be reviewed and consideration will be given to issues including stack heights and effective 

stack heights. No building wake effects were taken into account in estimating downwind 

concentrations from Fernald releases. 

10. For the purpose of deriving the Rn and Rn progeny releases from the silos, the TBD used the median 

values derived in the RAC 1995 report. Wouldn’t this approach be considered claimant-neutral as 

opposed to claimant-favorable? 

Best estimates (neither giving favor to the claimant, but not denying the benefit of doubt) are the 

preferred method of dose reconstruction. Regarding releases of Rn and associated progeny, a 

recent University of Cincinnati study has become available and the values in the TBD will be 

reconsidered in light of the new information. 

11. Page 17 of the TBD states that atmospheric dispersion factors (Χ/Q values) were derived assuming a 

wind speed of 3.2 m/sec and stability class F. Once the Χ/Q values were derived for a given distance 

between the release point and receptor (using the σy and σz values in Figures 4-3 and 4-4 of the TBD), 

an adjustment factor is applied to account for the frequency the wind blows toward a given receptor 

from a given source. Why didn’t NIOSH employ the conventional joint frequency approach to 

deriving average annual atmospheric dispersion factors? Furthermore, the selected wind speed of 3.2 

m/s does not appear to be claimant favorable. Please provide a justification as to why NIOSH is 

using this value for wind speed. 

The wind speed of 3.2 m/s is from the environmental report and the choice of stability class “F” 

came from the Safety Analysis report for the thorium overpack operation. 

12. Table 4-8 contains the estimated distances for receptors from contributing emission sources. For 

EA-6, the distance from the K-65 silos is given as 250 m, even though the geographic center of EA-6 

appears to be at a distance of about 100 m. The distance from the K-65 silos to EA-9 is given as 

2,000 m, even though the most distant point in EA-9 appears to be about 1,500 m away from the K-65 

silos. The distance to Plant 7 to EA-3 and EA-8 is 250 m in both cases, even though Plant 7 is 

located inside EA-7. Please explain the basis for the assumptions. 

The estimated downwind distances will be reviewed and revised or justified as necessary. 

13. The TBD states on page 16 that the respirable fraction (<10 μm) of U particles was determined to be 

65% on the basis of RAC (1995), Table E-1. It appears that for this calculation, the simple arithmetic 

average of data from 15 dust collector stacks was used. Table E-1 does not provide data on particle 

sizes from scrubber emissions (Plant 2/3 and Plant 8). Table E-8 of RAC (1995) indicates that the 

composite of U3O8 releases indicate that more than 75% of the emissions in the outlet had a particle 

size of less than 10 μm. Please explain how the fraction of 65% respirable particles is representative 

for the total of all U emissions. 

Upon review, we believe that the higher fraction of respirable particles should be considered in 

determining the total respirable uranium particulate from at least Plants 2/3 and 8. The TBD 

will be revised accordingly. 

14. Has NIOSH considered the contribution to the internal dose associated with the resuspension and 

inhalation of deposited Pb-210? 
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No, at this time NIOSH has not considered emissions of Pb-210 separately from the emissions of 

radon, because it is likely that assumed Rn intakes and the associated assumed equilibrium ratio 

of progeny are sufficiently large to account for intakes and associated doses from Pb-210 

environmental releases. 

15. Has NIOSH attempted to compare the pre-1989 derived atmospheric dispersion factors with the 

actual empirically determined atmospheric dispersion factors obtained using the actual monitored 

emissions and airborne radionuclide concentrations at monitored locations? 

The atmospheric dispersion factors have not been compared, but since the TBD was originally 

written, additional data have been received and comparisons are now possible. 

16. The footnote to Table 4-7 on page 19 suggests that the dispersion coefficients were multiplied by a 

factor of 0.5 for U and Th particulate aerosols, presumably to account for plume depletion, as 

explained in the paragraph below equation 4-3 on page 17. For most distance, plume depletion will 

be less than 50%. Please explain how it can be claimant favorable to apply a uniform plume 

depletion factor of 50% for all releases of particulates. 

Although the Pasquill-Gifford Equation used for gases in Equation 4-2 should be divided by two 

for application to particulate, and thus results in Equation 4-3, the footnote to Table 4-7 appears 

to indicate that it’s possible the numbers were divided in half again. The calculations will be 

checked and the numbers in Table 4-7 of the TBD will be updated if needed to reflect the 

appropriate values.. 

17. Equation 4-5 on page 35 of the TBD presents the method used to estimate the external radiation dose 

rates at each of the 11 grid locations. The basic approach was to use the actual measured dose rates at 

each of the locations where measurements were made, and then derive the dose rate at the grid 

locations, based on adjustments that take into consideration the distance from the source and the 

distance to the grid location using the inverse square law. One concern with this approach is that it 

only applies to point sources. Has NIOSH evaluated the degree to which this approach works for 

sources whose dimensions are large relative to the distance to the measurement location and/or the 

grid location? 

For most locations the distances compared to the source sizes are sufficiently large that a point 

source methodology is reasonable. For the few sources that might not be best approximated as 

point sources (e.g., the pits), the results are sufficiently close to actual measured results using 

these equations that the method appears reasonable. 

18. The purpose of deriving the external environmental exposure pre-1976, when there were no 

measurements, the doses were derived by comparing the U throughput in those years with the years 

for which there were external environmental dose measurements. What is the relevance of U 

production to external environmental dose in outdoor areas? Why did NIOSH not use U emissions 

instead, for instance? Were U isotopes the main external environmental dose problem throughout the 

Fernald site? Has NIOSH evaluated the degree to which the controlling factors remained unchanged 

over the years? 

The environmental occupational exposures were ratioed to the U production rates. The primary 

environmental external exposure would have been due to the radium-bearing material (Ra-226) 

in the K-65 silos and the thorium (Th-232) stored within several warehouses on the Fernald site. 

Uranium’s short-lived progeny, Pa-234m, contributes to the non-penetrating dose. This exposure 
 

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would have represented a baseline external exposure and would have incrementally increased 

based upon the throughput of uranium being processed within the process area. 

19. The TBD does not discuss the methods used to derive pre-1976 external environmental doses from 

the silos. How does NIOSH plan to reconstruct these doses? 

The method for extrapolating doses back to the pre-1976 periods is described in the TBD 

beginning with the last paragraph on p. 35. The method includes the dose from the silos, 

although the silo dose rates are not specifically called out in Table B-1 for pre-1976 periods. 

This is easiest to see by comparing the 1971–1975 and 1976 values in Table B-1, because the 

production rates were the same during these periods. 

20. How does NIOSH propose to reconstruct doses for the K-65 workers involved in handling 

Mallinckrodt K-65 residues, including the unloading of these residues and their loading into Silo 1? 

This is not considered environmental exposure that would be used to address unmonitored 

worker doses, rather it is part of the exposure in a radiologically controlled workplace and so is 

covered in Section 5.2.4 of the Fernald Internal Dosimetry Technical Basis Document. 

D. QUESTIONS RELATING TO INTERNAL DOSE (VOL. 5) 

1. What is the reference for the decontamination factor of 50 used for some Th-232 production 

activities? 

A review of this TBD resulted in no locating of a decontamination factor of 50 in the document. 

Please clarify this question. 

2. Table 2-1a assumes respirator-based decontamination by a factor of 50 for some operations (Vol. 2, 

pp. 12–13). But in Vol. 5, “at least a factor of 10” is given for decontamination, and it is said that 

respirator use was not consistent and a decontamination factor cannot be assumed (Vol. 5. pp. 22–23). 

Is a decontamination factor being assumed for uranium when air concentrations are used for intake 

estimation? If so, for which jobs and periods? And what is the value being used? 

To date, we are unaware of respiratory protection factors being used for Fernald dose 

reconstructions, and currently have no plans to apply these factors. (It’s conceivable that in the 

future on a case by case basis, where there are no bioassay that can be used to estimate intakes 

and it can be shown that the worker was included in a respirator fit test program and was 

wearing a respirator that such factors might be applied). Table 2-1a applies (inappropriately) a 

respiratory protection factor only to some operations or locations. The last column in Table 2-1a 

and its associated footnote b., and other similar columns and footnotes in the Site Description 

TBD tables (e.g., 2-2b) will be deleted. 
 

 

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3. Has NIOSH taken into account the dose reconstruction implications of the finding that respirators 

were judged at one point (1953) to be the “epitome of filth?”22

 Specifically, if respirators were stored 

in places or were worn so that they were susceptible to contamination on the inside, the intake could 

possibly be even higher than for those who did not wear respirators. Has NIOSH done interviews 

regarding jobs and periods during which respirators were worn and on the condition of the 

respirators? If so, SC&A requests the records of these interviews. Has NIOSH determined whether a 

central service (recommended in the memo quoted in the footnote) was implemented, and if so, 

when? 

The TBD recommends that no credit be taken for respirator usage despite a documented program 

for respiratory supply and maintenance. Intakes derived from urinalysis results, which are likely 

to be available for those who handled respirators, would account for intakes that occurred 

directly from respirators. Ingestion intakes will be added for thorium operational intakes, which 

currently are based on intakes calculated from air concentrations. CATIs include some 

information regarding respirator usage, but other specific interviews regarding respirators, their 

care and their usage have not been assembled, and would unlikely affect exposure assumptions. 

4. On page 11 (TBD, Vol. 2), it is not clear why thoria gel production for 1964 and 1965 was estimated 

based on a linear extrapolation of the quantity produced in 1966 through 1970. Can some 

justification for this assumption be provided? 

This question belongs in the section for Vol. 2 – the Site Description. Air monitoring and/or 

effluent release calculations are used to derive internal intakes and so this assumption does not 

affect dose reconstruction. 

5. Could NIOSH provide the flowchart of thorium processing? Was it similar to the Ames Laboratory 

flowchart? 

Simplified flow sheets are included in the Dolan and Hill (1988 report) report. We are not 

familiar with the mentioned Ames Laboratory flowcharts. Is a more complete reference to these 

documents available, so we can review them? 

6. How has NIOSH taken into account localized high concentrations of uranium dust in areas such as 

dust collector baghouses? 

Internal dose reconstruction is performed using uranium bioassay data, even if the intake 

occurred as a result of working in the high dust levels in the dust collector baghouses. 

7. Is NIOSH developing an internal dose co-worker model? If so, what periods would this apply to, and 

what data are being used? 

So far, there has not been a need to develop a FEMP coworker model for internal dose. 

22 Dr. Quigley to Charles Dees, “Industrial Case Study,” October 12, 1953, p. 3, on which Dr. J. W. Durkin 

appears to be quoted. The full quote, which has the name of one person (perhaps two) deleted from the document is 

as follows: “The other problem that became apparent in this situation is the poor care being given to the dust 

respirators. The ones observed by [blank] and myself near the Chip Burner were the epitome of filth. Apart from 

this, it would have been a perfect fomite [?] for the transfer of respiratory infection between employees. This simply 

corroborates the reiteration of [blank] that something should be done about the respirator situation – either the men 

must take better care of them, or central service must be provided.” An earlier part of the document notes that “there 

were two Dust-Foe respirators hanging on hooks” in the “shack-type office in the [Chip Burner] area.” 
 

 

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8. Has NIOSH compiled internal dose data into a database? If so, could it be made accessible on the 

Advisory Board’s section of the O Drive? 

At this point a NIOSH internal dose database is not available. There is a CEDR database, and if 

the Board Members have filed the appropriate paperwork for viewing CEDR data, access could 

be made available via the O drive). 

9. How is NIOSH going to reconstruct internal dose prior to 1953, since there do not appear to be data 

before 1953, as implied by the sentence, “A urinalysis program was administered at FEMP starting in 

1953 or possibly before” (p. 30 of Vol. 5). The table on the same page states that there are uranium 

bioassay data for 1952. Are there data for 1952? 

FEMP started to process radiological materials at the Pilot Plant in October 1951.The available 

data are adequate to estimate intakes from the beginning of radiological operations. In a quick 

review of the CEDR database for Fernald and some Fernald claims with employment prior to 

1953, some uranium urinalysis results from 1952 were observed. 

10. Since no bioassay data for thorium are available prior to 1990 – that is for the entire production 

period – how is NIOSH going to validate the dose estimates for thorium-232, as well as for its decay 

products, notably radium-224? 

Dose estimates are based on an understanding of the process, some air sampling measurements 

and default maximum credible intakes, derived from maximum air sample data. If a more 

comprehensive air monitoring database becomes available, its use will be considered. The 

concern is not clear about Ra-224, the alpha-emitting, short-lived progeny of Th-228, whose dose 

appears to be adequately accounted for in the assumption that the alpha activity measured in air 

only comes from the larger dose contributors Th-232 and Th-228. 

11. Since much of the thorium data is lost and many documents have apparently been destroyed (p. 18, 

Vol. 5), and since there are hardly any bioassay data or other data specific to thorium in the 

workplace, how is NIOSH going to ensure that the dose reconstructions are claimant favorable? How 

is NIOSH going to ensure that all plants where thorium was processed are included in its list? Could 

NIOSH provide all the interviews on which its analysis of thorium production and related issues is 

based? 

The TBD referred to interviews performed by Dolan and Hill (1988) and that reference is 

available in the Site Research Database. The dose reconstruction for thorium exposures includes 

a default assumption that is claimant favorable to the extreme and should address any credible 

exposure. The TBD recognizes that a few scattered operations with thorium were conducted in 

plant 4. Any suggestion in the interviews that a claimant could have been involved with thorium 

operations will have the conservative defaults applied. However, the documented data for the 

few operations outside the pilot plant, Plant 8 and 9 are few and some additional information 

search may clarify how to address this question. 

12. Given that thorium-232 DCFs are orders of magnitude larger than uranium for some organs, how is 

NIOSH going to address doses to uranium workers in the plants listed for thorium production (Plants 

8 and 9, the Pilot Plant, and possibly Plant 4) (a) during thorium production periods, and (b) due to 

resuspension of thorium dust during nonthorium production periods? 

The question of addressing possible residual thorium contamination from discontinued thorium 

operations is under consideration. 
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13. Could NIOSH provide the records that have been recovered in relation to thorium described at the 

bottom of page 21, Vol. 5? 

The thorium air sampling records that have been recovered can be found in the SRDB and can be 

provided. 

14. On page 22, Vol. 5, NIOSH states that “Therefore, the three Plants mentioned [Plants 8 and 9, and the 

Pilot Plant] should be considered the primary processing sites, although there is some evidence that a 

few isolated thorium operations occurred in other locations.” There seems to be no guidance for dose 

reconstruction at these other locations (such as Plant 4), and how the periods or workers who were 

exposed would be determined. How is NIOSH addressing the issue of thorium work in Plants other 

than Plant 8, Plant 9, and the Pilot Plant? 

Perhaps a clarification should be emphasized that dose reconstructions for claims that include 

evidence of thorium exposure should include thorium internal dose based on the default values in 

the TBD. This question will receive additional consideration. 

15. On page 22, NIOSH states that it is using BZ samples from lapel samplers to conservatively estimate 

thorium exposures. How is NIOSH taking into account the Y-12 study indicating that this is not a 

reliable way to make intake estimates, and that BZ-estimated intakes could be significant 

underestimates when compared with bioassay estimated intakes? 

The TBD statement on page 22 describes the current (modern) methods of controlling and 

assigning internal intakes – conservatively. If the questioner’s Y-12 reference is the Y-12 

Uranium Exposure Study (Eckerman and Kerr 1999 [Ref ID 11600]), it is clear that the intake 

estimation method proposed in the TBD is reasonable; in the Y-12 study the ratios of air 

concentration to bioassay derived intakes range from 0.11 to 1.38 with an average of 0.49 in 

Table 11 of the Y-12 study, indicating that if bioassay is the gold standard, Y-12 intakes derived 

from bioassay might be low in some cases by up to a factor of 9. However, the intakes in the Y-12 

study were reduced to account for respiratory protection factors ranging from 1 (no respirator) 

to 50, but typically in the 25 to 50 range. For FEMP claims there is no proposal to apply a 

respiratory protection factor to the FEMP BZA derived intakes. In addition, currently the more 

claimant-favorable missed intakes from bioassay rather than air concentration derived intakes 

have been used to estimate FEMP doses. Assigning intakes based upon breathing zone air 

sampling data collected in current day programs with appropriate collection and measurement 

techniques is recognized as a reasonable way to estimate intakes. 

16. Since enrichments of uranium-235 up to 20% were processed at Fernald, how does NIOSH justify the 

use of 2% enrichment as the default value after 1964? Given the large difference in specific activities 

and the fact that the fluorometric method was used for determining uranium content of urine, this 

would appear to be an assumption that would not be claimant favorable for some groups of workers at 

some times. Would it be possible to use a range of enrichments with a suitable distribution (or 

distributions for different time periods) instead? 

The amount of U of enrichments above 2% at FEMP was trivial (a few 55 gal drums compared to 

MTU). Also the exposures to these enrichments were less due to increased value, small amounts, 

need for additional criticality controls, etc. 

17. In Table 5-11, RU contaminant concentrations are given for plutonium-239, neptunium-237 and 

technetium-99. Although plutonium-239 is likely to have dominated the plutonium component of the 

contamination in mass terms, plutonium-238 could have been more important in activity terms. Has 
 

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NIOSH given consideration to the possibility of specifying a default mass concentration for 

plutonium, together with a default partitioning between plutonium-238, plutonium-239, and 

plutonium-240, to allow intakes of activity by radionuclide to be assigned? 

The Pu-238 was not a significant internal dose factor, as a result of processing primarily DU and 

low LEU. The method used to account for the dose from recycle uranium contaminants tends to 

be claimant favorable and uses the larger mass ratios to estimate intakes and it is likely that this 

worst-case method is sufficiently bounding to account for a small fraction of the higher specific 

activity Pu-238 in the mixture. 

18. In Table 5-16, is there any explanation why Pb-210 and Po-210 activity concentrations in Silo 1 

measured in 1993 are substantially less than would be expected based on the secular equilibrium 

concentrations that would be supported by the Ra-226 present? It is noted that this effect is much less 

marked in Silo 2. 

There are a number of possible explanations for the less-than-equilibrium ratios, but the most 

likely one is that at some point during the ore processing much of the Pb-210 (21 year half-life) 

was separated from the Ra-226. Much (if not all) of the K-65 residue in Silo 1 came from 

Mallinckrodt’s Destrehan facility, and some of the residues had been reprocessed in 1949 to 

extract additional uranium, which could have removed more lead. Silo 2 contained K-65 from 

Fernald beginning in 1952 and from Mallinckrodt in 1953 to 1956, when Mallinckrodt was no 

longer processing pitchblende. One would guess that there was less emphasis in “getting the 

lead out” by the time Silo 2 came into use (or perhaps there was more emphasis in controlling 

lead waste or releases to the environment). It is not clear how this would affect dose 

reconstruction, because it seems reasonable to use the measured ratios. 

19. How can the Rn-222 concentration of 2.3 WL given on page 27 of Volume 5 be justified as claimant 

favorable when it is based on the higher of only two samples from a single radon sample data sheet? 

Based on reviews of radon concentrations at sites that processed African as well as domestic ore 

and handled or stored its residues, such as Mallinckrodt and Linde Ceramics, the value of 2.3 WL 

appears favorable to the claimant. More information on radon at Fernald has become available 

and will be reviewed and incorporated into the site profile as necessary. 

E. QUESTIONS RELATING TO EXTERNAL DOSE (VOL. 6) 

1. Is NIOSH developing an external dose co-worker model? If so, what periods would this apply to and 

what data is being used? 

No external dose “co-worker model” is currently under development. 

2. Page 23 of the external dose volume mentions the use of co-worker data for missed doses? What 

criteria are being used to choose the co-workers for the missed doses? 

The term “co-worker” as used in the TBD referred to someone who worked “side-by side” or did 

exactly the same job as the worker who either lost his dosimeter or whose dosimeter results were 

lost or was not monitored for some unknown reason for that exchange period. It was not 

intended to imply anything other than that. 

3. Page 23 also mentions lost dosimeter results. What proportion of the data has been lost? 
 

 

 

 

 

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Dosimeter results have not been tabulated to estimate the proportion(s) of unavailable (because 

of dosimeter loss, record unavailability, etc.) results. The current sense is that the proportions 

are not likely to be large. 

4. Has NIOSH compiled external dose data into a database? If so, could it be made accessible on the 

Advisory Board’s section of the O Drive? 

Fernald external dose results were not compiled by ORAUT. To our knowledge the only 

databases that may be available are DOE’s REMS database and ORAU’s CEDR database. If the 

Board Members have filed the appropriate paperwork for viewing CEDR data, access could be 

made available via the O drive. Summary data from REMS are in the Site Research Database. 

5. The TBD discusses adjustments to dosimeter readings. In regard to radioactive dust settling on the 

dosimeter, the TBD states that dosimeters were in plastic bags “at times” (p. 11, Vol. 6).23 However, 

Volume 4 of the set of transition reports in the handover from NLO to Westinghouse discusses the 

application of adjustment factors to TLDs for a period between 1983 and October 1985. The use of 

this correction factor sometimes resulted in negative radiation dose estimates. The correction factors 

resulted in changes (according to the calculations shown in the datasheets) of 6% to 663%. In the 

examples given in the report, the largest magnitude correction of 1,652 millirem was applied to a dose 

of 1,291 millirem, resulting in a net negative estimated dose equal to -361 mrem. 24 The practice was 

used from 1983 (when TLDs were introduced) to October 1985, when its regular use was 

discontinued. However, it appears to have been continued in an ad hoc fashion after that date.25 

While doses with high percentage corrections (more than 50%, therefore including negative dose 

estimates) were not automatically entered into the dose record, it is unclear what exactly was done. 

The TBD does not discuss this problem, although it indicates some difficulties in the initial period of 

TLD testing due to a problem in the algorithm, notably for shallow dose (p. 12, Vol. 6). Has NIOSH 

investigated this problem and how the resultant doses might be interpreted? Since the TBD 

acknowledges that plastic bags were used only “at times,” has NIOSH investigated the periods when 

this was not the practice? Were correction factors applied during such periods? Does NIOSH have 

documentation indicating the periods when dosimeters were in plastic bags? Section 6.5 on 

adjustments to dose does not discuss the use of the correction factors described above. How is 

NIOSH going to take them into account? 

The dose of record during the period in question, 1983–1985, was from the same film dosimeter 

in use from 1954–1985 and not from the bagged TLDs (see Table 6-12, pg.22). The TLD model in 

question was one under development and was not the dosimeter of record. The TLD model that 

was finally put into service in 1985 was the first to be DOELAP certified. As for correction 

factors, none were needed because plastic bags did not cover the dosimeter of record prior to the 

1985 service date and no data was found that indicated the use of plastic bags after this date. 

However in discussions with ex-Fernald employees involved with the dosimetry program the use 

of plastic bags did occur and the same calibration practices prevailed. 

23 “An additional radiological concern at several locations at FEMP occurred when workers were subjected 

to high levels of radioactive material-bearing dust. This widespread source of contamination was a concern for 

personal dosimeters, so at times the dosimeters were enclosed in plastic bags for protection against dust 

contamination. The manner in which these contaminated dosimeters were handled was not identified; however, this 

should not be an issue in dose reconstruction because the dosimeters were calibrated in plastic bags and no 

adjustments were made to the dosimeter results for either Hs(0.07) or Hp(10).” (TBD, Vol. 6, p. 11) 24 Feed Materials Production Center, Final Phase-in Report, Vol. 4 of 15, Environment, Safety and Health, 

Westinghouse Company of Ohio, January 17, 1986. See Attachment 3 for the datasheets. 25 Ibid. p. 15. 
 

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6. Vol. 6 of the TBD discusses correction factors for geometry. Has NIOSH taken adequate account of 

some jobs where the badge readings were unlikely to have any systematic relationship to the organ 

dose? One such job, stamping numbers on ingots, was photographed by Robert del Tredici in 1987. 

The photograph shows the worker sitting astride an ingot stamping an ID number on its flat face; it 

can be provided upon request. His film badge is dangling from his coverall pocket parallel to the face 

of the ingot. His body shields the radiation from behind. The use of wrist badges is evident. The 

angular response correction factors (Table 6-7) do not address this problem. 

The stated situation, while against all company rules, regulations and procedures, happened 

frequently. Instructions were given describing how dosimeters were to be worn so that they 

would measure the highest exposure to the body. The time spent in conducting this activity, e.g. 

stamping an ID number on an ingot, is a very small fraction of the individual’s total working time 

and therefore of the individuals total exposure. Any individual claim involving a situation as 

depicted by the photo will be evaluated on a case-by-case basis. No generic correction factor is 

available or thought necessary for this particular situation. 

7. On page 22 of Vol. 6, NIOSH states that “Corrections to the FEMP-reported dose are required, due to 

uncertainties in the recorded data and lack of significant data, especially prior to 1980.” How much 

pre-1980 data is missing? What happened to the individual external dose records for the pre-1980 

period that caused a significant amount of data to be missing? 

The “lack of significant data” referred to the information provided thereafter in the TBD 

regarding external dosimeter response-related details, and was not meant to imply that individual 

external dose records were missing. The corrections to pre-1985 data are due to the responses of 

the dosimeters and their inability to measure the contribution to the total dose from those photon 

radiations of less than several hundred keV and in particular the L-x-rays of both U and Th. The 

standard error for film dosimeters of this period and for these low energies is estimated to be+/- 

30%, a value given in several TBD’s, (Y-12, Hanford, IAAP). Since a portion of the total doses 

lie in these lower energy ranges, a correction is suggested in order to maintain a “favorable to 

claimants” position. 
 

 

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ATTACHMENT 3: SUMMARY OF THE CONFERENCE CALL OF 

AUGUST 18, 2006, ON THE FERNALD SITE PROFILE REGARDING 

SC&A QUESTIONS SENT TO NIOSH 

For NIOSH and ORAUT: Mark Rolfes, Mel Chew, Cindy Bloom, Bryce Rich, Liz Brackett, 

Bob Morris, Elyse Thomas, Tom LaBone, Jack Fix, Karen Kent, Mutty Sharfi, Kenny Fleming 

For SC&A: John Mauro, Harry Pettengill, Arjun Makhijani 

These notes are a complement to the written answers provided by NIOSH to SC&A, which are 

reproduced in Attachment 2. Those answers are not repeated here, unless necessary to provide 

context for the notes of the discussion. The questions submitted by SC&A to NIOSH are shown 

in Attachment 1. Only those questions on which there was substantive discussion beyond the 

written replies provided by NIOSH are summarized here. NIOSH written responses reproduced 

here from Attachment 2 are indented and italicized. Furthermore, a full list of NIOSH actions to 

revise the TBD has been extracted from the Attachments in this review and provided in the text 

of the review in Section 5.0. The conversational style is retained to provide a flavor of the nature 

of the technical exchanges. This summary is not verbatim. 

A. GENERAL QUESTIONS AND QUESTIONS RELATING TO VOLUMES 1 AND 2 

OF THE TBD 

1. Could NIOSH provide SC&A with the notes of its interviews with site experts? 

The Site Profile development team only interviewed four former Fernald workers. 

Unfortunately, there were no comments from interviewees that related directly to issues 

or assumptions in the TBDs, so documentation of these interviews was not retained. 

SC&A: Are there any e-mail exchanges of the interviews? 

ORAUT/NIOSH: There were e-mails, but the interviews were casual in nature. They focused 

on thorium. They were done in the context of preparation of the Dolan report (1988). We do not 

have any thing more than the reference to the interviews in the Dolan report, nor do we know if 

those interviews were documented. 

SC&A: Did the interviews play a role in the thorium section, and if so, could NIOSH ask Dolan 

whether the documentation is available? 

ORAUT/NIOSH: Yes, the interviews did play a role. Much more documentation is becoming 

available on thorium. When we did the TBD, information on thorium was limited, but we have 

received and are expecting more thorium information, which will be considered and incorporated 

in a revision of the TBD. 

SC&A: Are you revising the TBD, and what is the schedule – is it within the next 30 days? 
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ORAUT/NIOSH: We are going through the bi-annual TBD review and revising it. We are 

behind schedule. We are not going to publish the revised TBD in the next month. We could 

respond to your TBD review as part of the revision. 

SC&A: Are the new documents, especially regarding thorium, on the O Drive? 

ORAUT/NIOSH: We are placing the documents on the Site Research database. Reference 

numbers will be sequential, so you can find the latest documents easily. 

ORAUT/NIOSH action: Place thorium documents on the Site Research database as they become 

available. NIOSH will also prepare a brief summary of where ORAUT/NIOSH is in the TBD 

revision process as soon as possible, so it can be reflected in the SC&A TBD review. SC&A 

will make a list of the major revisions that are now planned or being produced. 

2. How many workers were there at Fernald? 

ORAUT/NIOSH: The TBD reflects at specified times the size of the workforce and SC&A was 

considering the total number of workers over time. Both are smaller than at some large DOE 

sites, hence the use of the term “relatively small.” 

SC&A: Yes, that seems right; we agree. 

3. Regarding cumulative production. 

SC&A: The production numbers in the TBD seem low. There are shipment and receipt data that 

indicate production of uranium (all types) of around half a million metric tons. 

ORAUT/NIOSH research was centered on some material balance reports and the recycle 

uranium work. The mass balance mainly for RU is in OTIB-53 in final review. 

SC&A action: Arjun will send data and/or references to Mark Rolfes. 

4. Are the uranium ore processing flowsheets similar to that developed by NIOSH for 

Mallinckrodt showing the various stages of filtering and concentrations of Ra-226, Th-230, 

Pa-231 and Ac-227? 

ORAUT/NIOSH: The Fernald flow sheet was similar to Mallinckrodt, but would have 

incorporated better designs. There were some differences. There is a text that talks about the 

differences. 

ORAUT/NIOSH action: Look at flowsheet for Fernald and compare to Mallinckrodt. At 

Fernald, the waste that went into Silo 2 is the main concern, since that was the waste from 

processing of relatively high-grade ores at Fernald. The first step would be to create the Fernald 

flowsheet and try to benchmark that with MCW. 
 

 

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5. Would the ratios of radionuclides in the K-65 Silo 1 or Silo 2 be applicable to specific waste 

streams, or do they represent mixtures of actual waste streams that were all discharged into 

the silos? The question relates only to Fernald waste streams and not the Mallinckrodt 

materials in the silos. 

ORAUT/NIOSH: Comprehensive radionuclide-specific analyses for Silo 2, like those reported 

in the 1990s, have not been located at this time. 

6. What is the scientific justification for using the ratio of Th-232 to U atmospheric emissions 

to determine in-plant thorium contamination? 

ORAUT/NIOSH: Those ratios are not being used in dose reconstruction. The internal dosimetry 

part of the TBD specifies how thorium doses are estimated. The uranium-to-thorium ratio was 

used as a sanity check. The TBD is being revised to reflect the extensive data on thorium that is 

becoming available, including more results from thorium air samples and thorium lung count 

data. 

SC&A: The assumptions in the Site Description are not the same as those in the environmental 

and internal dose sections of the TBD. This is confusing. 

ORAUT/NIOSH: Vol. 2 was developed early on. It will be made consistent with Volumes 4 

and 5, the environmental and internal dose sections. 

SC&A: This would be useful and clear up this confusion by making the needed changes. 

B. QUESTIONS RELATING TO MEDICAL DOSE (VOL. 3) 

1. This question was about records of telephone communications as the basis for which the 

possible use of a PFG unit at Fernald was ruled out. 

No other information regarding telephone conversations beyond that included in the TBD 

is available. 

SC&A: Are we to take the response to mean that no record of these conversations is available? 

Specifically, we are looking for documented information as to why the use of a PFG unit is ruled 

out. The only person who worked in the period of interest and who was interviewed was Nurse 

Smith, so validating that conversation is central to this issue. Relying on people who joined in 

the 1980s may not be viewed as reliable for determining whether there were PFG units in use in 

the 1950s. 

ORAUT/NIOSH: There are no formal records of those conversations. They were just 

documented in the TBD and that is all there is. 

SC&A: Who helped determine and therefore rule out PFG use as concluded in the TBD? 
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Mel Chew: I helped with this. I don’t remember the specific conversation about the PFG unit. 

It came up, but I just don’t recall it. 

SC&A: If you look at the [NIOSH] guidelines, especially OTIB-0006, there is an appreciation 

of the need to consider the use of PFG units as a fast and efficient screening tool for the high 

employee volume being hired at new DOE facilities built during the 1940s and 1950s. PFG was 

in common use at most DOE facilities in the 1950s, so you should not default to x-rays as 

opposed to PFG units without validation. 

SC&A: In my review of the TBD medical section, I don’t recollect any discussion of film size. 

If you find smaller than 14” by 17” film, that is usually a dead giveaway that there was use of a 

PFG unit. I don’t recall that there was anything stated about the size of the x-ray film in the 

TBD. 

SC&A: Also of concern is whether there is any indication that x-rays of employees may have 

been taken offsite or outside the Fernald medical clinic. 

ORAUT/NIOSH: We have no reason to think that that was the case. How would we look at 

that? 

SC&A: If you look a number of x-ray films, you can see if you have different levels of 

definition (contrast, etc.), film sizes, and such. Specifically, any PFG film will be smaller in 

size. So you can infer whether they were made in one location or more, and whether a PFG unit 

was used. 

NIOSH/ORAUT action: Elyse will go to the Fernald records center, look at the some of 

archived records, including films, and try to resolve some of these questions. 

SC&A: If there are the actual films to review and not just the medical interpretation, it will be 

easy to check if PFG was used. 

2. Were data for Bennett unit calculated or measured? 

ORAUT/NIOSH: The data were calculated. There were also data from Hanford. The calculated 

values were higher than the measured Hanford values, so this appears to be claimant favorable. 

SC&A: We suspected that early survey information [Tables 3-10 and 3-14] was calculated. In 

our records search, we were unable to find an actual survey attributable to the Bennett unit. I 

understand that has been done. How about the Keleket unit? Have you looked at that again? 

They assumed a half-value layer of 2.5 mm of Al. 

ORAUT/NIOSH: We’re not yet ready to answer the question about the Keleket unit. Can you 

clarify the question you want answered? 

SC&A: The TBD states that the Keleket unit was surveyed in 1961 and the results of that survey 

help to validate the dose calculations for that unit. Our review shows the purpose of the survey 
 

 

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was to establish whether unwarranted external doses resulted from workers inadvertently 

wearing their dosimeter during annual x-ray exams. There were problems also with the unit not 

operating in the full diagnostic range and the use of 2.5 mm of Al as added filtration, which 

appears to be assumed rather than measured. Can NIOSH demonstrate with actual survey data 

that the HVL of Keleket was empirically measured and output was later measured in the full 

diagnostic range of the unit? 

Follow-up post-discussion question from Harry for NIOSH: “Can NIOSH provide SC&A with a 

copy of the actual Bennett unit survey that clearly identifies the date and unit number?” 

3. Did NIOSH examine other explanations for the black line at the bottom of the radiographs, 

other than assuming that collimation was always used at Fernald from the earliest days? 

SC&A: This assumption is not defensible without an actual examination of the film by a 

technician to determine the reason for the black line at the bottom of the film. Such a single line 

at the bottom of the film alone is unlikely to be due to collimation. 

ORAUT/NIOSH action: NIOSH will review this issue again, and look at the actual films in the 

record center during a forthcoming visit and will report back to SC&A its findings. 

Supplementary post-discussion question from Harry for NIOSH: NIOSH, in Section 3.1.4 of the 

TBD, concludes that from 1952–1980, collimations were always utilized. Can NIOSH show by 

actual documentation that the Keleket and Bennett units had collimators installed, and do any 

studies exist to show they were routinely checked for alignment error or leakage of the 

collimators? 

4. Are doses from x-rays taken after workplace accidents going to be included in dose 

reconstructions? 

In accordance with 42 CFR 81 and 82, only medical exposures that were performed for 

medical screening and required as a condition of employment are included in the 

occupational medical dose. Diagnostic and therapeutic procedures not required for 

medical screening are not included.” X-rays taken after workplace accidents are 

diagnostic and so are not included in dose reconstruction. 

SC&A: The rationale for this question was not so much intended to cover whether a person was 

rolled in for x-ray because he had a workplace injury. Perhaps a clarification is in order. The 

question should state: Were some of the prescribed and often repetitive screening x-rays, which 

occurred outside the routine physical exam schedule also considered as a “condition of 

employment?” So far it has not been stated in the TBD that they were. 

ORAUT/NIOSH: Pelvic and lumbar spine exams were also required [in the DOE complex] and 

those would be covered. They were typically given on an annual basis or more often for periods 

in the 1940s and in the 1950s. However, we asked about these x-rays for Fernald and were told 

that they did not do them there. 
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SC&A: My understanding is this resulted from a conversation you had with a manager in 2003. 

So the question remains whether there is documentation to establish whether screening exams of 

all types were included if they occurred. Is there a basis for knowing what happened in the 

1950s? 

Elyse: Usually what we tried to do was to determine whether x-rays were screening or not, 

whether they were performed on a large number of people who were asymptomatic, or, for 

instance, for tuberculosis screening. The clue usually is in the data submitted by the DOE site. 

If you see an exam just on a few people, then it is likely that this was not a screening. But if 

there were a large number of lumbar spines, for instance, then there is a good chance that was a 

screening method. Sometimes we have the [x-ray] records, but not the protocol for taking the xrays. For Fernald, we may have seen lumbar spines in just one of the claimant files. But I am 

not sure of that right now. For an individual dose reconstruction, they count up the number of xrays in the file and decide whether the file is complete. If it seems that there were routine annual 

x-rays, then they assign that, even if records for some years are missing. We usually have a list 

of x-rays taken for the individual employee. Some sites use forms that make it clear if an exam 

was for screening. But at most sites, at least in the early years, this was not clear. 

SC&A: Was there a numerical criterion for how many people had to be x-rayed before one 

would conclude that it was screening that would be considered as a condition of employment? 

ORAUT/NOISH: No. You get a feel for it as you go through the claimant cases; there is no 

hard and fast rule. 

SC&A: Fernald was a uranium metal foundry from its earliest days. So it seems reasonable that 

it would have been important to establish whether new workers had a pre-existing back injury. 

Can NIOSH further validate that routine screening exams for respirator users, asbestosis 

workers, food handlers, etc., were included in medical dose estimates, even when they occurred 

at different times than when routine physical exams occurred? 

ORAUT/NIOSH action: Elyse will look for evidence of lumbar spine x-rays and other screening 

exams that might have been a requirement for employment, and if it appears that these exams 

were performed at Fernald, she will look for the period of applicability. She will also look for 

information to address the Fernald PFG issue. 

5. The TBD states that a review of claimant files showed that 15% of the claimants reported 

that retakes occurred. Could NIOSH provide SC&A with the data compilation used to 

determine the retake rate? 

No other information regarding X-ray retake rate, beyond that included in the TBD, is 

available. 

SC&A: But what is the 15% rate based on? Was it a default value? 
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ORAUT/NIOSH: As best as I recall, it came from Ron Kathren, and was taken from OTIB– 

0006. We don’t know whether it was a default value. If it was, then we will correct the 

language and say so. 

SC&A: Retakes happen if the technicians decide they have a poor picture, or they may be 

ordered by the doctor to do it again, if he wants more detailed information. One is a retake and 

the other is really a new exam. Actual retakes hardly ever end up in the medical record. As 

such, it is very hard to estimate retakes unless you do a facility-specific study. Overall, an 

assumed 15% retake rate for Fernald—given the equipment and timeframe—might be borderline 

or low. 

ORAUT/NIOSH: A 30% uncertainty is applied to the organ dose. It is from OTIB-0006 and 

presumably includes consideration of retakes. 

SC&A: The 30% uncertainty does not have to do with retakes and does not include them, as the 

30% uncertainty only covers systematic or measurement error. The retake rates would vary a lot. 

The reason it stood out to us was that the TBD indicated the 15% came from a “review of 

claimant files.” 

ORAUT/NIOSH action: Is it a Fernald statement or a generic statement? Clarify where the 

assumption of a 15% retake rate comes from. 

C. QUESTIONS RELATING TO ENVIRONMENTAL DOSE (VOL. 4) 

1. Why did the TBD use the source term developed by Fernald and not by the Radiological 

Assessments Corporation by the CDC, which is much higher (about 310,000 kg compared to 

about 175,000 kg used by NIOSH)? 

The original revision of the Fernald Occupational Environmental Dosimetry Technical 

Basis Document (OEDTBD) used the Boback data to estimate exposure to site releases 

because it was believed that its use would be sufficiently conservative and the resulting 

exposures would represent exposure estimates that would be favorable to the claimant. 

Use of the release data compiled by RAC (1995) would simply add to the existing 

conservative estimate. 

SC&A: The RAC source term is not a conservative one; it is their median estimate. The Fernald 

1987 and 1988 source terms were flawed, for instance, because they did not take into account 

that scrubber efficiencies in Plant 8 were very low sometimes; far below the lowest 

manufacturer-specified efficiency of 70%. CDC spent $6 million on the RAC study, whose 

source term is more scientifically sound than the Dolan and Hill source terms. 

ORAUT/NIOSH: We felt that the values documented in the Boback report were conservative 

and claimant favorable. We can change it. It would be claimant favorable to use a higher RAC 

number. 
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SC&A: The use of RAC is not about what is claimant favorable. We believe that the RAC 

source term is much more technically defensible, and it specifies uncertainties. Note that the 5th 

percentile value of the RAC source term is about the same as the upper bound of the 

Westinghouse source term. So there are non-trivial differences here. 

ORAUT/NIOSH action: NIOSH will look at this issue again. 

2. Why did the TBD use the Th source term from Boback 1987 and the 1988 supplement, rather 

than the RAC 1995 source term? 

See response to C.1 above. 

SC&A: This question was in error. The RAC study does not have a thorium source term. 

ORAUT/NIOSH: The RAC Report indicates in Table L-13 relative concentrations of Th to U 

based upon liquid waste discharges. The Boback report also provides airborne Th release data. 

Both information sources will be assessed, and the TBD revised as necessary. 

3. Table 4-4 on thorium emissions may not be conservative as stated in the TBD, for instance, 

due to low scrubber efficiency. 

The RAC 1995 document provides a description of the scrubber efficiencies at both 

Plants 2/3 and 8 that differs from the Dolan and Hill (1988) assumptions. Updates to the 

TBD are warranted based on the differences in the efficiency estimates. 

ORAUT/NIOSH action: Both the RAC and Boback Reports provide information sources 

concerning airborne thorium emissions that will be assessed and the TBD revised as necessary. 

4. According to a tabulation by NLO, a significant fraction of the U releases from Fernald were 

of an episodic or accidental nature, influencing the environmental doses. How is NIOSH 

going to account for episodic releases in estimating environmental internal dose for 

individual dose reconstructions? 

Episodic (and operational) stack releases are included as annual integrated emissions 

within the tables in the TBD. Over extended periods of time, these integrated emissions 

provide means of estimating internal exposures for individuals who were not monitored 

and who would not have required monitoring because of their low potential for exposure 

during their employment. In accordance with program guidance given in ORAUTPROC-0031, the derived maximum site-wide annual median intakes via inhalation and 

ingestion will be used to estimate doses for these unmonitored individuals when other 

dose-estimating information is not available. 

SC&A: There are really three issues in regard to estimating internal environmental doses that 

could affect the use of the annual average Gaussian plume model; episodic releases, ground level 

vs. elevated releases, and building wake effects. The NIOSH approach is claimant favorable for 
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using stability Class F, but it is not for the other assumptions. For example, the building wake 

problem is important onsite for the radon emissions from the silos. 

ORAUT/NIOSH: We did not have a lot of data when the TBD was prepared, so this was one of 

the approaches to use. If there were a large number of episodic releases, then they can be treated 

in an annual average release model. 

SC&A: We agree with that. NIOSH has drawn upon the work of RAC, which was for offsite 

dose estimation for onsite purposes. This is not appropriate. This is a problem we have found 

across the board. 

ORAUT: Are you suggesting another model? 

SC&A: You used puff advection at Hanford. There should be some guideline as to when an 

annual average Gaussian approach can be used and when the more complex approaches should 

be used. If releases are frequent and random, then you can use annual average, but for large 

releases every few months, you want to use puff advection. It could make a lot of difference in 

that case. 

(This discussion also covers questions 9, 11, 12, and 15, which are omitted from this summary.) 

SC&A action item: SC&A will communicate some preliminary work to NIOSH, and at the same 

time, finish its site profile review. 

5. How were fugitive U and Th emissions calculated? 

For fugitive emissions, EPA guidelines were used to calculate emissions from the waste 

storage and production areas. Reference: Method for Estimating Fugitive Particulate 

Emissions from Hazardous Waste Sites. U. S. Environmental Protection Agency, 

Cincinnati, Ohio, August 1987. EP/600/2-87/066 PB87-232203. 

SC&A: This generic estimate does not seem appropriate. There are Fernald data from the 1950s 

or earlier where fugitive emissions were estimated. The fugitive emissions from some practices 

appear to have been substantial. For example, there were leaks in outdoor equipment, dust 

escaping from doors and windows opened during blowouts, and dust being blown about from 

keeping thorium trays in doorways. These data should be used. Also the EPA equations give 

very low values for dust loadings compared to empirical values for dust loadings. The EPA 

approach gives 1 to 2 micrograms per cubic meter; empirical data show that this is low by 2 or 3 

orders of magnitude. 

Mel Chew: We should review this as a generic approach. This was an early approach, and it 

should be reviewed generically. Is that what you are asking? 

SC&A: SC&A will look at the dust loading, but it may not be the most important environmental 

source term. The other items we’ve mentioned above may be more important. 
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SC&A action: Arjun will try to dig up documents on fugitive emissions and send them to 

NIOSH for use in revising the site profile. 

7. In developing the radionuclide-to-U ratios, the TBD used average observed values. Has 

NIOSH considered using the 95th percent confidence level of the mean, as opposed to the 

true mean, as a more claimant-favorable strategy? 

ORAUT/NIOSH: Remember that environmental doses are for unmonitored workers. For other 

workers, the approach is specified in Vol. 5 of the TBD. Coverage of Fernald workers in terms 

of monitoring for both external and internal dose was quite thorough. NIOSH experience with 

claims shows that this was the case. 

10. For the purpose of deriving the Rn and Rn progeny releases from the silos, the TBD used the 

median values derived in the RAC 1995 report. Wouldn’t this approach be considered 

claimant-neutral, as opposed to claimant-favorable? 

Best estimates (neither giving favor to the claimant, but not denying the benefit of doubt) 

are the preferred method of dose reconstruction. Regarding releases of Rn and 

associated progeny, a recent University of Cincinnati study has become available and the 

values in the TBD will be reconsidered in light of the new information. 

ORAUT/NIOSH: Again, the environmental dose TBD is for unmonitored workers. A separate 

protocol is used for monitored workers, as specified in Vol. 5. For these workers, the dose 

assignment is higher. We are re-evaluating all this in light of new information. Specifically, 

NIOSH has new information from the University of Cincinnati. 

14. How about resuspension of Pb-210 that has built up in the soil from deposition? 

ORAUT/NIOSH: This will be minor, since lead-210 has a long half-life relative to radon. The 

radon blows offsite to a large extent, and most of the lead-210 build-up will be there. Also, the 

lead-210 component of resuspension dose would be much smaller than the other components like 

uranium, due to high environmental releases. 

SC&A: But there is a disequilibrium for lead-210 in the silos, indicating that there is a deficit, 

which must be somewhere. 

ORAUT/NIOSH: We don’t expect to see lead-210 in equilibrium, because the K-65 residues 

were reprocessed at Mallinckrodt in 1949 before being shipped to Fernald. The lead-210 may 

have been stripped at Mallinckrodt in the barium sulfate process. 

SC&A: In that case, it would be perhaps two half-lives of lead-210, and that may be part of the 

explanation for the Silo 1 measurements. 

SC&A action: SC&A will do a sample calculation of Pb-210 deposition to estimate build-up and 

see if this is an issue. 
 

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17. What about the validity of the inverse square law for external radiation for areal sources? 

For most locations the distances compared to the source sizes are sufficiently large that a 

point source methodology is reasonable. For the few sources that might not be best 

approximated as point sources (e.g., the pits), the results are sufficiently close to actual 

measured results using these equations that the method appears reasonable. 

SC&A: What measurements were used? 

ORAUT/NIOSH: The external dose values were from aerial survey data. 

SC&A: This appears appropriate. 

18. For pre-1976 period, there are no external dose environmental data. Why did NIOSH use 

production rather than emissions as the key variable for estimates? 

SC&A: The external dose factors are not mainly production-dependent, since we know that 

emissions per unit of production emissions were bigger in the 1950s than later on. Hence, 

production should not be used to back-extrapolate any dose parameter. 

ORAUT/NIOSH: This is unmonitored for workers. 

SC&A: Why not scale it according to emissions? SC&A indicated they will revisit this issue 

and see if they still have a question. 

20. How does NIOSH propose to reconstruct doses for the K-65 workers involved in handling 

Mallinckrodt K-65 residues, including the unloading of these residues and their loading into 

Silo 1? 

ORAUT/NIOSH: This is really an internal dose issue and is addressed in Section 5.2.4 of the 

Internal Dose TBD, which includes information for allocating intakes from associate 

radionuclides. This question is not an environmental dose issue. 

D. QUESTIONS RELATING TO INTERNAL DOSE (VOL. 5) 

1. What is the reference for the decontamination factor of 50 used for some Th-232 production 

activities? 

A review of this TBD resulted in no locating of a decontamination factor of 50 in the 

document. Please clarify this question. 

SC&A: There are many references to such a decontamination factor in Vol. 2, for instance in the 

footnotes to Tables 2-1a, 2-2a, 2-3a, etc.—about 10 instances in all. 
 

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ORAUT/NIOSH: This is actually a respirator protection factor used in Vol. 2 and is not being 

used in dose reconstruction. We will fix Vol. 2, so it is compatible with Vol. 5. Fernald was an 

early TBD and needs revision. This also clears up question 2 in this section. 

2. Vol. 2 and Vol. 5 are not consistent in regard to respirator decontamination factors. Explain. 

See answer to question 1 in this section. Assuming no respirator was used takes care of question 

3 as well. 

7. Is NIOSH developing an internal dose co-worker model? If so, what periods would this 

apply to, and what data are being used? 

So far, there has not been a need to develop a FEMP coworker model for internal dose. 

ORAUT/NIOSH: The reason that a co-worker model is not needed is that essentially everyone 

was monitored. 

8. Has NIOSH compiled internal dose data into a database? 

At this point a NIOSH internal dose database is not available. There is a CEDR 

database, and if the Board Members have filed the appropriate paperwork for viewing 

CEDR data, access could be made available via the O drive). 

ORAUT/NIOSH: At the time of TBD, the data was in two archives. Now data are available. 

Bioassay data are the primary data, and there is really no need to go back and do this, since 

everyone essentially was monitored. 

9. How will internal doses before 1953 be calculated, given that there might be no bioassay 

data? 

ORAUT/NIOSH: Don’t know how many claims include only exposures in late 1951 through 

1952, but for claims that include later bioassay, chronic intakes can start on the day of 

employment. There are also some 1952 bioassay records. 

10. How will pre-1990 thorium doses be estimated? And how about radium-224? 

ORAUT/NIOSH: Ra-224 dose is small relative to the other radionuclides. 

SC&A: We agree regarding Ra-224. But the TBD is not on the mark regarding thorium. The 

suggested method would be an underestimate, at least for the early years. Also, processing was 

done in more plants than indicated in the TBD. 

ORAUT/NIOSH: We are getting more information. We have been able to get lung counting 

data for thorium. There are thorium chest counts from the late 1960s and early 1970s. The data 

are being developed, but they do not have them at this point; the DOE has them. Thorium chest 

counts were done on everyone who had uranium counts. They reported only thorium-232 and 
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thorium-228. [Thorium-230 was not included.] The current default assumption typically results 

in a determination that a chest count would be positive, but the claims processed to date indicate 

that the default assumption typically results in an overestimate of intake. There is a box of 

records for everyone who was monitored at Fernald. 

SC&A: How do you know if the people who worked on thorium in the 1950s and 1960s were 

monitored? You have to be careful to back-extrapolate both, because it may not be the same 

people who were exposed. We did not see that maximum air concentration data were cited or 

used in the TBD. Rather, there is the 1050-MAC recommendation for thorium intake that seems 

rather arbitrary. 

ORAUT/NIOSH: We believe it is claimant favorable, but we are re-evaluating the thorium 

exposures. Thorium records will continue to be added to the Site Research database as they 

become available. 

11. What is NIOSH doing to ensure that all periods and plants where thorium was processed are 

covered, since much of the thorium data is lost and many documents have apparently been 

destroyed (Vol. 5, p. 18)? 

SC&A: There are data showing it was processed in Plant 6, for instance. 

ORAUT/NIOSH: We are looking at where it was processed again. 

12. Question about thorium resuspension doses to uranium workers during thorium production 

and after it. 

The question of addressing possible residual thorium contamination from discontinued 

thorium operations is under consideration. 

SC&A: How about thorium exposure in the 1980s? 

ORAUT/NIOSH: We are looking at residual contamination in general. This is a program-level 

issue, for which we are trying to develop generic approaches for these estimates. There may also 

be data available to address this. 

SC&A: Since the residual contamination was a mixture of uranium and thorium contamination, 

the model suggested for Bethlehem Steel may be useful. 

SC&A action: Arjun will send Bethlehem Steel reference to Mark Rolfes for Cindy. 

13. Could NIOSH provide the records that have been recovered in relation to thorium described 

at the bottom of page 21, Vol. 5? 

The thorium air sampling records that have been recovered can be found in the SRDB 

and can be provided. 
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ORAUT/NIOSH: NIOSH is uploading newly found documents as they go along. 

15. On page 22, NIOSH states that it is using BZ samples from lapel samplers to conservatively 

estimate thorium exposures. How is NIOSH taking into account the Y-12 study indicating 

that this is not a reliable way to make intake estimates, and that BZ-estimated intakes could 

be significant underestimates when compared with bioassay estimated intakes? 

The TBD statement on page 22 describes the current (modern) methods of controlling 

and assigning internal intakes – conservatively. If the questioner’s Y-12 reference is the 

Y-12 Uranium Exposure Study (Eckerman and Kerr 1999 [Ref ID 11600]), it is clear that 

the intake estimation method proposed in the TBD is reasonable; in the Y-12 study the 

ratios of air concentration to bioassay derived intakes range from 0.11 to 1.38 with an 

average of 0.49 in Table 11 of the Y-12 study, indicating that if bioassay is the gold 

standard, Y-12 intakes derived from bioassay [sic, the original response is miswritten 

and the word “bioassay” should be replaced with ”air concentration.”] might be low in 

some cases by up to a factor of 9. However, the intakes in the Y-12 study were reduced to 

account for respiratory protection factors ranging from 1 (no respirator) to 50, but 

typically in the 25 to 50 range. For FEMP claims there is no proposal to apply a 

respiratory protection factor to the FEMP BZA derived intakes. In addition, currently 

the more claimant favorable missed intakes from bioassay rather than air concentration 

derived intakes have been used to estimate FEMP doses. Assigning intakes based upon 

breathing zone air sampling data collected in current day programs with appropriate 

collection and measurement techniques is recognized as a reasonable way to estimate 

intakes. 

SC&A: The Eckerman and Kerr study indicates the reverse. Air concentration-derived intakes 

were lower by up to a factor of 9. 

ORAUT/NIOSH: That is because a respiratory protection factor for inhalation intakes was used. 

Without that, the air intakes are higher. 

SC&A action: Revisit the Eckerman and Kerr study. 

ORAUT/NIOSH: Post-discussion, it was noted that the ORAUT response erroneously referred 

to bioassay when air concentration was meant. A correction has now been added in square 

brackets within the response. 

16. Since enrichments of uranium-235 up to 20% were processed at Fernald, how does NIOSH 

justify the use of 2% enrichment as the default value after 1964? 

The amount of U of enrichments above 2% at FEMP was trivial (a few 55 gal drums 

compared to MTU). Also the exposures to these enrichments were less due to increased 

value, small amounts, need for additional criticality controls, etc. 

SC&A: Some quantitative justification of “trivial” would be useful. It would provide some 

assurance that this is not a problem assumption for some workers. It would be desirable to 
 

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document and give some quantitative expression to the term “trivial.” We are surprised that 

there is not a careful materials account for uranium enriched to more than 2%, given that other 

sites seem to track even natural thorium down to kilogram quantities. 

ORAUT/NIOSH: We are sure that it was small. It was not a requirement to do materials 

accounts for uranium enriched to less than 20%. Other sites did materials accounts for lower 

enrichments and thorium for their own purposes. It was not headquarters telling them to do it. 

18. In Table 5-16, is there any explanation why Pb-210 and Po-210 activity concentrations in 

Silo 1 measured in 1993 are substantially less than would be expected based on the secular 

equilibrium concentrations that would be supported by the Ra-226 present? It is noted that 

this effect is much less marked in Silo 2. 

There are a number of possible explanations for the less-than-equilibrium ratios, but the 

most likely one is that at some point during the ore processing much of the Pb-210 (21 

year half-life) was separated from the Ra-226. Much (if not all) of the K-65 residue in 

Silo 1 came from Mallinckrodt’s Destrehan facility, and some of the residues had been 

reprocessed in 1949 to extract additional uranium, which could have removed more lead. 

Silo 2 contained K-65 from Fernald beginning in 1952 and from Mallinckrodt in 1953 to 

1956, when Mallinckrodt was no longer processing pitchblende. One would guess that 

there was less emphasis in “getting the lead out” by the time Silo 2 came into use (or 

perhaps there was more emphasis in controlling lead waste or releases to the 

environment). It is not clear how this would affect dose reconstruction, because it seems 

reasonable to use the measured ratios. 

NIOSH provided SC&A with a reference where measurements of radon in the head space of the 

K-65 silos are published. Waste management proceedings WM-4383, Eger, Jacob Engineering, 

Langner, Grand Junction Field office. 

If there is good agreement between head space concentration of radon as estimated by RAC and 

Langner measurements in the Fernald head space, that would settle this issue. 

SC&A action: Check this publication to see if there an issue here (in terms of a discrepancy 

between measured and calculated radon concentrations). 

19. Rn-222 intake assumption of 2.3 WL is the higher of only two samples from a single radon 

sample data sheet. 

ORAUT/NIOSH: Data from other sites show 2.3 WL is claimant favorable. And there are more 

data available now that are being analyzed. 

SC&A: A comparative table for Fernald compared to other sites would be useful. 
 

 

 

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E. QUESTIONS RELATING TO EXTERNAL DOSE (VOL. 6) 

3. Page 23 also mentions lost dosimeter results. What proportion of the data has been lost? 

Dosimeter results have not been tabulated to estimate the proportion(s) of unavailable 

(because of dosimeter loss, record unavailability, etc.) results. The current sense is that 

the proportions are not likely to be large. 

SC&A: Is there some notion of what “not likely to be large” means? 

NIOSH: The individual dose records are pretty complete. The missing or lost data would be 

well under 5% based on experience. There is no real gap here. 

4. Has NIOSH compiled external dose data into a database? If so, could it be made accessible 

on the Advisory Board’s section of the O Drive? 

ORAUT/NIOSH: No action is planned. NIOSH will confirm with the Board. 

5. The TBD discusses adjustments to dosimeter readings. In regard to radioactive dust settling 

on the dosimeter, the TBD states that dosimeters were in plastic bags “at times” (p. 11, 

Vol. 6).26

 However, Volume 4 of the set of transition reports in the handover from NLO to 

Westinghouse discusses the application of adjustment factors to TLDs for a period between 

1983 and October 1985. The use of this correction factor sometimes resulted in negative 

radiation dose estimates. The correction factors resulted in changes (according to the 

calculations shown in the datasheets) of 6% to 663%. In the examples given in the report, 

the largest magnitude correction of 1,652 millirem was applied to a dose of 1,291 millirem, 

resulting in a net negative estimated dose equal to -361 mrem.27 The practice was used from 

1983 (when TLDs were introduced) to October 1985, when its regular use was discontinued. 

However, it appears to have been continued in an ad hoc fashion after that date.28 While 

doses with high percentage corrections (more than 50%, therefore including negative dose 

estimates) were not automatically entered into the dose record, it is unclear what exactly was 

done. The TBD does not discuss this problem, although it indicates some difficulties in the 

initial period of TLD testing due to a problem in the algorithm, notably for shallow dose 

(p. 12, Vol. 6). Has NIOSH investigated this problem and how the resultant doses might be 

interpreted? Since the TBD acknowledges that plastic bags were used only “at times,” has 

NIOSH investigated the periods when this was not the practice? Were correction factors 

applied during such periods? Does NIOSH have documentation indicating the periods when 

26 “An additional radiological concern at several locations at FEMP occurred when workers were subjected 

to high levels of radioactive material-bearing dust. This widespread source of contamination was a concern for 

personal dosimeters, so at times the dosimeters were enclosed in plastic bags for protection against dust 

contamination. The manner in which these contaminated dosimeters were handled was not identified; however, this 

should not be an issue in dose reconstruction because the dosimeters were calibrated in plastic bags and no 

adjustments were made to the dosimeter results for either Hs(0.07) or Hp(10).” (TBD, Vol. 6, p. 11) 27 Feed Materials Production Center, Final Phase-in Report, Vol. 4 of 15, Environment, Safety and Health, 

Westinghouse Company of Ohio, January 17, 1986. See Attachment 3 for the datasheets. 28 Ibid. p. 15. 
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dosimeters were in plastic bags? Section 6.5 on adjustments to dose does not discuss the use 

of the correction factors described above. How is NIOSH going to take them into account? 

The dose of record during the period in question, 1983–1985, was from the same film 

dosimeter in use from 1954–1985 and not from the bagged TLDs (see Table 6-12, pg.22). 

The TLD model in question was one under development and was not the dosimeter of 

record. The TLD model that was finally put into service in 1985 was the first to be 

DOELAP certified. As for correction factors, none were needed because plastic bags did 

not cover the dosimeter of record prior to the 1985 service date and no data was found 

that indicated the use of plastic bags after this date. However in discussions with exFernald employees involved with the dosimetry program the use of plastic bags did occur 

and the same calibration practices prevailed. 

SC&A: We cannot accept this statement at face value. The datasheet reproduced in the 

Westinghouse transition report has badge numbers on it and implies that it is part of the workers’ 

records. Some cross-walking of the data in the transition report with individual dose records is 

essential before it can be assumed that none of these calculated doses were in worker dose 

records. 

SC&A action: Arjun will find Ref. 5 and send it to Mark, since it is not on the NIOSH database. 

ORAUT/NIOSH action: ORAUT/NIOSH will review this issue. 

6. Question of organ dose versus dose recorded on the badge due to location of the source 

relative to badge and organ. Example of a worker sitting on an ingot to stamp an ID number 

on it shown in a photograph taken by Robert del Tredici in 1987. 

The stated situation, while against all company rules, regulations and procedures, 

happened frequently. Instructions were given describing how dosimeters were to be 

worn so that they would measure the highest exposure to the body. The time spent in 

conducting this activity, e.g., stamping an ID number on an ingot, is a very small fraction 

of the individual’s total working time and therefore of the individual’s total exposure. 

Any individual claim involving a situation as depicted by the photo will be evaluated on a 

case-by-case basis. No generic correction factor is available or thought necessary for 

this particular situation. 

SC&A: Given the huge number of ingots made, it seems unlikely that it was a “very small 

fraction of the time.” Furthermore, if you look at the fact that the badge is perpendicular to the 

floor and more or less to the source, the dose to the gonads is likely to be far greater than the 

recorded dose, even when some shielding is taken into account. Hence, even if the amount of 

time is small, the dose to the gonads is likely to be much greater than that recorded on the badge. 

ORAUT/NIOSH: This issue may be addressed adequately in OCAS-TIB-013. 

SC&A: A modeling of this problem using the ATTILA model that NIOSH used for 

Mallinckrodt would be useful and should be done for this job. 
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SC&A Action: Send the Mallinckrodt review reference to Mark. 

ORAUT/NIOSH action: ORAUT/NIOSH will assess the geometry issue. 

7. On page 22 of Vol. 6, NIOSH states that “Corrections to the FEMP-reported dose are 

required, due to uncertainties in the recorded data and lack of significant data, especially 

prior to 1980.” How much pre-1980 data is missing? What happened to the individual 

external dose records for the pre-1980 period that caused a significant amount of data to be 

missing? 

ORAUT/NIOSH: This is not about individual missing data, but about dosimeter response data, 

for which a correction is suggested. 

SC&A: We seem to have misinterpreted the TBD statement as missing individual data. 
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ATTACHMENT 4: SITE EXPERT INTERVIEWS 

Interviews were conducted with 48 former Fernald Environmental Management Project (FEMP), 

Department of Energy Ohio Field Office oversight personnel, and other individuals having 

knowledge of site operations. Years represented by those interviewed range from 1952-present. 

The interviews were conducted by Ed Sensintaffer and Kathryn Robertson-DeMers, members of 

the SC&A Fernald review team. The purpose of these interviews was to receive first-hand 

accounts of past radiological control and personnel monitoring practices at Fernald, and better 

understand how operations were conducted. Interviews were held in person from February 13– 

17, 2006. Interviewees were selected to represent a reasonable cross-section of production areas 

and job categories. Interviewees were originally obtained with the assistance of the DOE, the 

labor union, National Institute for Occupational Safety and Health (NIOSH) worker outreach 

meeting minutes, worker outreach groups and retiree organizations, and former health physics 

staff. 

Workers were briefed on the purpose of the interviews and the FEMP Site Profile. They were 

asked to provide their names, in case there were follow-up questions. Participants were 

reminded that they would be provided the opportunity to review the interview summaries prior to 

inclusion into this report. Interviewees were told that there were aspects of operations that were 

classified and that this information could not be divulged. To ensure classified information has 

not been included in the interview notes, the notes were reviewed by a classification officer prior 

to release. 

Former and current FEMP employees, and subcontractors interviewed worked in various 

operations throughout the site. Some of the facilities associated with their work included the 

Pilot Plant, Plant 2/3, Plant 4, Plant 5, Plant 7, Plant 8, Plant 9, the pit area, and the silos. Some 

individuals had access to all areas of the plant. The job categories represented included the 

following: 

• Bioassay Laboratory Manager 

• Carpenter 

• Chemical Operator 

• Construction Maintenance 

• Construction Laborer 

• Electrician 

• Health and Safety Division Management 

• Health Physicist 

• Heavy Equipment Operator 

• Inspector 

• Laborer 

• Laundry 

• Machinist 

• Millwright 

• Pipefitter 

• Production 
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• Radiation Monitor/Radiological Control Technician 

• Radiological Engineer 

• Security 

• Shipping and Receiving 

• Staff Engineer Environmental Monitoring 

• Transportation 

• Welder 

The information the workers provided to SC&A has been invaluable in providing a working 

knowledge of the site operations and the safety program. All interviews have been documented 

and summarized below. This is not a verbatim discussion, but a summary of information from 

multiple interviews with many individuals. The information provided by the interviewees was 

based entirely on their personal experience with Fernald. It is recognized that site expert and 

former Fernald workers’ recollections and statements may need to be further substantiated, 

however, they stand as critical operational feedback and reality reference checks. These 

interview summaries are provided in that context. FEMP site expert input is similarly reflected 

in our discussion. With the preceding qualifications in mind, this summary has contributed to 

our findings and observations. 

General Information 

The plant was divided into what was referred to as the Metal Area and the Chemical Area. The 

movement of the work force was dependent on the job responsibilities. There were individuals 

who worked throughout the site, as well as individuals who were assigned to a particular plant. 

At first, maintenance was assigned to cover a particular area. There was a maintenance pool 

located in Building 12. Eventually, maintenance personnel were used throughout the site. 

Transportation was deployed throughout the site. Chemical Operators tended to stay in an area, 

although they could bid on jobs in other areas to get reassigned to another plant. Operationspecific workers were more prone to stay in a single plant in the early years of operations. 

Females were not originally allowed to work in the production areas, because Fernald did not 

have a fertile-female policy. In 1978 or 1979, a woman started work with the Transportation 

Department. In 1984, another woman went to work in waste treatment. The number of women 

in production areas increased through the 1980s. When a woman became aware of being 

pregnant, she advised Medical and was then sent to work on the “clean site.” 

Workers from Fernald were sent to other sites on occasion. For example, a contingent of six 

Fernald workers was sent to the Niagara Falls site to retrieve thorium. The thorium drums were 

not suitable for shipment, so the material had to be repacked (about 150–200 drums of material). 

Workers involved noticed differences between the RadCon program at FEMP and that at Niagara 

Falls, with Niagara Falls having the safer program. In addition, Fernald workers were sent to an 

area near the South Carolina and Georgia border to drum thorium packed material and ship it to 

Fernald. Two groups of six workers were sent to the area for about 3 weeks. There was a 

collaborative effort between Reactive Metals, Inc. (RMI), in Ashtabula, Ohio, and Fernald for a 

period of time. RMI extruded uranium metal billets for Fernald. Security personnel were sent to 

other DOE sites for training. 
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There was an abundant amount of overtime for employees that wished to work it. It was 

determined in accordance with company policy of the time. When an individual accepted 

overtime, he was required to work an additional 8 hours. Overtime was not broken into 

increments smaller than 8 hours for the hourly workers. During Uranyl Nitrate Hexahydrate 

(UNH) operations, work continued 12 hours per day during the week and 8 hours per day on 

Saturday and Sunday. The guidelines adopted by the union in the mid-1980s allowed an 

individual to work 2 shifts back to back and up to 84 hours in a week. The company violated 

this guideline at times. Prior to the 1980s, average overtime ranged from 15–25 hours per week. 

There was a slowdown in overtime during the 1980s; however, it picked up again during the 

cleanup, especially at the silos project. The salaried workers interviewed did not report working 

much overtime. 

Operations personnel were under pressure to meet specific quotas. For example, site experts 

indicated that in the production area, they were required to make 100 derbies per shift. Once an 

individual met his quota, the individual could work at a more relaxed pace. 

Security 

National Lead Company of Ohio, Inc. (NLO), maintained tight security control during the 

production years. When NLO ran Fernald, Security worked under the prime contractor in 

support of the Atomic Energy Commission and later the Department of Energy. During the 

production years at Fernald, Security had a great deal of authority. In general, the rule was 

“Don’t Ask” related to processes and types of radioactive material, especially during the years of 

tight security. 

When Fernald first started, there was a fence around each of the individual plants. Employees 

were required to have authorization to enter a particular plant. In 1961, there was a fence added 

and the area around the laboratory building became a controlled area. Access was allowed only 

to those individuals with a need to know. This was about the same time Fernald started to 

receive recycled uranium. Entrance could only be gained through a manned gate guarded by 

Security between the Pilot Plant and the Laboratory. The Chemical Warehouse and all 

production buildings had a 2-person rule. This stopped being enforced during the accelerated 

cleanup. 

There were walking tours within the security fences, and driving tours of the perimeter. The 

guard would go to the guardhouse and pick up the clock key. For the east clock run, they were 

required to visit the garage (warehouse), Plant 4, Plant 6, Plant 9, the warehouse near Plant 9, the 

maintenance building, the service building, and finally the Administrative Building. Many of the 

plants had multiple Detex clocks that had to be punched. The west clock run covered the 

remainder of the Fernald site. During these tours, they were looking for evidence of access to 

unauthorized areas. Dust deposited on their uniforms as they completed their tours. Guards 

spent up to 5 days in the production areas per week. The off-shift worked the production area. 

Security personnel were responsible for providing escorts for visitors and construction 

employees. The escortee had to be within sight of the Security Guard at all times. As an escort, 

they could go to any of the areas onsite. At times, escorting would be their only assignment for a 

week. When the plant first started, there was a requirement for two guards to escort personnel. 
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There were times during escorting when there were respirators used by production personnel; 

however, security was not required to wear it. They were not provided with escape respirators. 

Security was involved in escorting trucks with incoming and outgoing materials. The truck was 

escorted onto the site to the building receiving the material. Security was required to verify the 

seals on the trucks as they came on and went off the Fernald site. They also verified that the 

paperwork was appropriate. There were a few incidents where the Bill of Lading did not match 

the material shipped. At times when transport vehicles were onsite, checking the vehicle was a 

part of their tour. Trucks delivering material came from all over the country. For shipments 

arriving by train, Security was required to meet the train at the gate, inspect the train cars, and 

ride the train onto the plant site. Security was not responsible for inventorying the material 

shipped to and from the site. In 1989, production was shut down and the emphasis at the site 

turned to remediation. Security no longer had to escort material onsite. 

Security would report to the Security Building to obtain their assignment for the day. They then 

went to the locker room and changed into their uniform. Dosimeters were stored at the Security 

Building. They were required to wear their uniforms in the production area during their tours. 

They did not change into coveralls like other employees. The dosimeter was the only difference 

in their dress between the clean area and the production area. When they went into the 

production area, they wore a uniform plus a dosimeter. These same uniforms were also worn 

into clean areas of the plant. Whereas other plant staff had two pairs of shoes (one for the hot 

side and one for the cold side), security used a single pair of shoes for all areas of the site. They 

were not provided with shoe covers. Employees had a single locker to store their uniform in. 

When they were on duty, this is where they stored their personal clothing. 

Security logbooks containing job assignments, information on material escorted, and information 

on events were maintained. Reports were issued for security infractions providing the details of 

the occurrence. These reports were maintained in a log by the lieutenant or sergeant. 

All classified material had to be locked in a safe over night. If Security found a classified 

document not properly stored, Security Headquarters was notified and the document was 

confiscated. There were a lot of occurrences at first until the employees learned the 

consequences. Individuals were required to clean out their records on an annual basis. 

Classified documents that were no longer needed were put through a shredder. Confidential 

records and above were burned. Numbered classified documents had to be sent to Central 

Records when no longer needed. Once the stringent security controls on the site were lifted, 

there were only limited amounts of material destroyed. 

Production Process 

Belgium and African ore were received at Fernald starting in the 1950s. Production was 

responsible for receiving the raw material, which was transported in via railcar or truck. The 

material shipped by the railcars primarily came in drums. The cars were unloaded and empty 

containers were reloaded onto the cars. Some of the cars came in loaded with lime and decolite. 

The Pilot Plant was used for numerous evaluations and experimental tests. Evaluations included 

areas such as refinery operations, hexafluoride reduction, derby pickling, and ingot casting. This 
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plant also housed equipment used for other purposes. This plant was used to produce derbies 

prior to Plant 5 being constructed. Derbies were produced by reducing UF4 green salt with finely 

granulated magnesium metal. Most green salt was produced by the refining process versus by 

UF6 reduction. The UF6 reduction process occurred at Fernald until it was taken over by other 

DOE sites. It involved vaporization of solid UF6 to produce gaseous UF6, and reduction of UF6 

to UF4. Thorium production activities started in the Pilot Plant in 1964 and continued until 1980. 

Ore was conveyed to Plant 2/3. This plant was responsible for conversion of uranium material to 

uranium trioxide, UO3, or orange oxide. Material was dissolved in nitric acid to produce UNH. 

UNH was purified and separated from impurities (i.e., raffinate). The UNH was stored for 

further processing. The solution was boiled down to a concentrate and under went 

denitrification, converting the material to orange oxide. The orange oxide was removed with a 

manual suction process known as gulping. The operators did not like to participate in gulping, 

because it involved heavy labor, work in elevated temperatures, and exposure to fumes. They 

reported that respirators were not commonly used during this process. Scraps and residues 

created by the process included metal oxides and radium-bearing sludge. 

The orange oxide was transported to Plant 4 using mobile hoppers. At times, Fernald received 

orange oxide from offsite. UO3 was converted to uranium tetrafluoride, UF4, or green salt by 

reduction and hydrofluorination. The green salt came out in a hopper and was packaged in 100– 

250 lb cans to be sent to Plant 5. The processes used in Plant 4 involved very high temperatures. 

Plant 5 reduced UF4 to high purity derbies through a process called reduction. Green salt was 

blended with magnesium metal granules and the charge put into a magnesium fluoride-lined 

reactor vessel (the charge was also referred to as a bomb). The lining process was referred to as 

“jolting.” The bomb was capped and the lid was bolted on. It was then placed in a Rockwell 

Furnace and heated to 1400° for approximately 1.5 hours. The bomb remained in the furnace 

until it had fired. The operators could observe this on a watt meter. The material was allowed to 

cool. The contents of the bomb were dumped out, and the derby was separated from the MgF2 

and byproducts using manual and mechanical processes. The MgF2 would have to be chipped 

off the derby with chisels and hammers, or cleaned with wire brushes. The slag was fed into 

chutes and recycled. Once separated, the derby was weighed, labeled, and stored on skids until 

needed. The derbies and scrap metal were melted in crucibles and cast into ingots for shipment 

to Plant 6. 

Difficulties the operators encountered in the Plant 5 process included frequent blow-outs, where 

a hole would develop in the lid or bottom of the bomb during the firing. The blow-outs resulted 

in evacuation of the area and sometimes occurred as often as two to three times per shift. Also, 

during the removal of the derbies, the slag chutes would become plugged. To unplug these 

chutes, operations would have to use jackhammers and/or manually remove the material. 

Plant 6 was responsible for the production of slugs from ingots. The uranium ingots were passed 

through a blooming mill to produce billets and sheared. The billets were reduced to the final rod 

dimensions, depending on where the rod was to be used. Some of the machines used in this area 

included shears, straighteners, automatic screw machines, centerless grinders, lathes, J-L 

machines, chaffers, cross machines, and rapid boring machines. Initially, the J-L machine was 

the only self-contained machine in the foundry area. The cast uranium ingots were treated in a 
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neutral salt (NuSal) bath to harden the material. The NuSal bath contained potassium carbonate 

and lithium carbonate, and were heated to approximately 1300° F. The metal was pickled, and 

machining chips and tailings compressed into briquettes. If not adequately covered with water 

and solvents, the chips and sometimes chunks of uranium would catch on fire. The product was 

then sent to the Inspection Department, where it was inspected for pits, seams, dimensions, and 

handling defects. Ultrasound testing was used to check for flaws under the surface. If the slug 

was good, it was packaged for shipment. These machines required a lot of preventive 

maintenance internal to the units. 

Plant 7 operated from 1954–1956 and was shut down in 1956. The plant was responsible for 

converting UF6 into UF4, which was used at Plant 5. There was a high demand for uranium 

metal during this period. The UF6 was provided to Fernald by the gaseous diffusion plant at 

Paducah. This process supplemented the production of UF4. Other Fernald plants were modified 

to increase production of UF4, so Plant 7 was no longer needed. After shutdown, the area was 

used to store enriched uranium and as a maintenance shop. 

Plant 8 received the bomb reduction liner material from Plant 5 in hoppers. It was emptied at an 

unloading station and moved to a surge hopper through a jaw crusher. The material was fed into 

an oxidation furnace where the metallic uranium was converted to black oxide (U3O8). The 

material was further ground and fed into digestion tanks, where it was dissolved in hydrochloric 

acid. The undissolved solids were filtered out and sent to the scrap dump. The uranium filtrate 

was sent to a precipitation tank, where it was converted to uranyl ammonium phosphate (UAP). 

The UAP was dried and sent to the refinery. The recovery process was eventually changed to 

produce ammonium di-uranate. 

Plant 9 produced derbies, ingots, slugs, and washers of various enrichments. With the exception 

of the washer production, the operations were similar to those in Plant 5 and Plant 6. The plant 

also had a process for chemically decladding unirradiated fabricated fuel elements. In about 

1955, Plant 9 was involved in making thorium metal. The thorium started as crystals and created 

high quality thorium oxide. This was shipped to Hanford and Bettis. The west side of Plant 9 

was considered the thorium or chemical processing area. The east side was where the machining 

operations took place. There was a large incinerator outside to the southwest used to burn chips 

and tailings. 

The raffinate was sent to the Hot Raffinate Building, where it went through a process to separate 

the Ra-226 and uranium. Hot barium sulfate was used as a precipitate. Portions containing 

radium and uranium were drummed and sent out. Some of the filter cake slurry was pumped out 

to Silos 1 and 2. 

Remediation/Waste 

The U.S. government obtained ore from the Belgium Congo for use at Fernald. The ore 

belonged to Belgium, who had planned to extract radium and precious metals from the waste 

stream. An agreement was eventually made between the Belgium and U.S. governments for 

Fernald to take on the responsibility for the waste. 
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Operable Unit 3 (OU3) was the Environmental Protection Agency’s designation for the former 

production area at Fernald. Chips and paint were the primary samples collected from OU3 

structures for characterization. The general approach to sampling remedial action sites is to 

survey and find the highest amount of activity. The sample was taken from this area. The 

raffinate stream was characterized in the mid-1980s. Analyses included evaluation of 

transuranics. The raffinate was pumped from the process area into Pit 5 for disposal. These 

waste pits were also characterized. 

The site maintained six engineered pits. Pits 1–3 were really one pit. Materials were either 

pumped to the pits or transported by truck out to the pits and dumped in. All sorts of material, 

including slurries, solid waste, depleted uranium, etc., were added to the pits. During the 

remediation of the pits, derbies, ingots, graphite molds, and other radioactive materials were 

found. The uranium chips would periodically catch on fire. 

Remediation of the pits involved pulling the water off, removing the contents to a predetermined 

depth, and performing soil sample analysis. If the soil samples did not meet the cleanup criteria, 

additional digging was required. During remediation, there were general assumptions made 

about what each pit contained. Pits 1–4 and Pit 6 contained U-238, debris, small pieces of metal, 

crucibles, cold traps, drums, building material, bags of asbestos, and other garbage from the 

production areas. Some of the radioactive material found in the pits was in pure form. Pit 5 

contained raffinates. There was a Burn Pit at Fernald, which was used to burn just about 

anything. Residue still remained in the pit until it was remediated. A berm was built from the 

west side of Pit 3 to the Burn Pit, but the berms were not well defined. 

The Clear Well Pit was used to decant water from the waste pits and other areas of the site. It 

was essentially used as a settling pond. This pit contained any radionuclide found onsite. Water 

was processed out and eventually released. During remediation, 30 feet of sludge was found in 

this pit. On the east side of the site, radium ash that had settled out from the Sewage Treatment 

Center was found. 

There were areas of the site that were expected to be clean that were found contaminated during 

remediation. For example, during excavation in the former Administration area of the site, air 

sample results showed up 850,000 times the permissible limit. There was a holdup of 

radioactive material in the piping and ductwork, including thorium in the process piping at the 

Pilot Plant, black oxide in ducts at Plant 5, radioactive material in the duct work in the 

Administrative Building, radioactive material in the ventilation ducts and the dishwasher vent 

stack in the cafeteria area, and dried UNH in pipe alley. 

The Plant 1 Storage Pads, located outside, held about 125,000–180,000 drums in 1989. The 

outdoor environment would sometimes cause the drums to rot. At times, the bottom would fall 

out of the drums. Many drums required overpacking. Other plants also had storage areas. 

Construction Trades 

Several of the construction trade personnel were temporarily assigned by their company to 

Fernald. Many of them left and returned several times. They provided construction and 

demolition support for the Fernald contract, as defined under the Davis-Bacon Agreement. 
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Maintenance and similar support services were provided by onsite employees. The construction 

trades were involved in activities site wide. Some of the construction trade jobs included the 

following: 

(1)	 Removal and installation of asbestos and insulation from buildings 

(2)	 Construction of railroad tracks to support K-65-related work 

(3)	 Building demolition, including removal of hoods, flooring, walls, dust collectors, 

ductwork, tanks, furnaces, etc. (Plant 1, Plant 2/3, Plant 5, Plant 6, Plant 8, the 

Administration Building, the Production Laboratory, etc.) 

(4)	 Transfer Tank Area (TTA) Remediation 

(5)	 Pouring concrete 

(6)	 Removal of brick and piping in pipe alley 

(7)	 Equipment setup and take down (e.g., scaffolding) 

(8)	 Removal of the Old Tank Farms 

(9)	 Building the airlock for the thorium overpacking project 

(10) Soil remediation throughout the site, including remediation of Silos 1 and 2 

(11) Waste pit drudging and other related work 

(12) Labor support 

(13) Installation or renovation of areas within production buildings 

(14) Installation of the Bentonite on the silos 

Construction trades workers moved from site to site as work became available. Some of the 

other DOE and Atomic Weapons Employers facilities that site experts worked at included 

Portsmouth Gaseous Diffusion Plant (Piketon), the Mound Plant, and the General Electric 

Evendale Plant. As subcontractors moved around the complex, they noticed the differences in 

radiological control implementation at the various sites. For example, Piketon implemented 

Personnel Contamination Monitors (PCMs) prior to Fernald. 

Tools used at the facility were surveyed by Fire and Safety and sometimes confiscated, due to 

contamination. This was especially true of wood-handled tools. 
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Radiological Hazards 

The radiological hazards associated with the plants are summarized below. 

Plant or Building Concerns for Field Radiological Control 

Plant 1 (Ore Assay and Milling) All uranium isotopes, Ra-226, beryllium 

Pilot Plant (Ore Silos) Th-230-contaminated material, enriched uranium, 

handled Paducah material 

Pilot Plant Annex U-238 

Plant 2/3 Uranium ore, Ra-226, and Th-230 in the raffinate stream 

East End Plant 2/3 U-238 

Plant 4 Natural uranium, depleted uranium, and enriched 

uranium, UF4 

Plant 5 (Metals Production Plant) NU and DU, beryllium 

Plant 6 Uranium and thorium-contaminated material and furnaces 

Plant 8 (Recycle Plant) Uranium (all isotopes) and Th-230 

Plant 9 (Special Projects Plant) EU metal, thorium metal, beryllium 

Building 54A U-238, depleted uranium 

Building 13A U-238, U-235, Th-230, Th-232, trace contaminants of 

Pu-238, Pu-239, Pu-241 

Building 64 Thorium storage 

Building 65 Thorium storage 

Building 61 (Quonset Hut 2) ThO2 

Quonset Hut 1 (Q-1) Thorium storage after overpack 

Building 67 Thorium storage 

Building 68 Thorium storage 

Building 69 Decontamination Facility - Uranium, Th-230 

Silo 1 Rn, Th-230, Ra-226 (full list is on EDESK) 

Silo 3 Th-230 + D, Ra-226 + D 

Pits including Burn Pit and U-238, derbies, small pieces of metal 

Clean Well 

Pit 5 Raffinates; Th-230 

Fernald had real-time radiography devices. There was a Co-60 source kept in a vault in the south 

warehouse of the Pilot Plant. This system was complete with interlocks. In the 1980s, additional 

soil had to be dumped and distributed around a portion of the building to increase shielding. The 

source had been in place long before this was done. There were also Phillips Constant Potential 

X-ray Units used for drum inspections. These units were used in an interlocked area. The 

integrity of welds was routinely checked with dyes or by visual inspection. When x-rays of 

welds were required, the objects were sent to the drum inspection booth in the Plant 1 Chemical 

Warehouse. 

Red drums and black drums were stored separately. In the warehouse, small cylinders of 

material were stored on a wooden pallet. These cylinders were red and were spaced 

appropriately to prevent a criticality. Security personnel remember seeing Fissile Material signs 

associated with this material. 
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Chemical Operators had a wide variety of responsibilities. Some of the high-exposure jobs 

included manning the dumping stations, cleaning equipment (i.e., dust collectors, reduction pots, 

crucibles, furnaces, reaction vessels, etc.), inventorying the rabbit hutches, and decontaminating 

areas when needed. Graphite molds were cleaned with a broom handle and steel wool. After the 

removal of the MgF2 from the uranium, individuals would stick their heads down as far as they 

could to clean the slag out of the pot. During this operation, there was no respiratory protection 

worn. These job responsibilities provided opportunities for exposure to high concentrations of 

radioactive material. A Chemical Laborer performed the same type of jobs, and was in training 

to become a Chemical Operator. 

There were both building-specific maintenance crews and a general maintenance pool. The 

general maintenance pool could be sent anywhere on the Fernald site. Although an individual 

may be assigned to a particular plant, he may be assigned to another plant during overtime. 

There were shop areas near the production buildings and a central shop area for handling 

maintenance on equipment. There were areas in the plants accessed by maintenance that were 

not routinely occupied (e.g., tanks, entry into pots). Contamination was present in these areas. 

Tools in the production area were generally contaminated. Some maintenance workers had “hotside tools” and “cold-side tools.” Maintenance personnel also had tool boxes, which they took 

from area to area. When they started to monitor tools in these tool boxes, they were found to be 

contaminated. 

Laborers stamped the cores, shipped materials on conveyors, packaged products, and loaded 

transport vehicles. They had to strap the material down, bringing them in close proximity to 

uranium. Supervisors, clerks, and administrative support personnel had offices in the production 

area. The ventilation system in production buildings was recirculated air, potentially exposing 

those in the administrative areas of the building. The offices tended to be dusty. A clerk was 

responsible for tracking the uranium as it was received and shipped. 

Transportation Labor was responsible for a wide range of duties, including unloading rail cars, 

hauling waste to the disposal pits, transporting material (e.g., samples, orange oxide, green salt, 

uranium metal, molds, drums, etc.) between plants with fork trucks and tow motors, and loading 

and banding offsite shipments of ingots, slugs, and derbies. When using the Tow Motor, the 

drums were not always secured adequately, so the drums would fall off and break open. This 

was a fairly routine occurrence. When transporting red drums, a Radiological Control 

Technician (RCT) had to accompany the Tow Motor operator. 

Uranium Characteristic 

Enriched uranium, depleted uranium, and natural uranium were all handled. The maximum 

allowed enrichment at the site was <20% U-235. Small quantities of enriched uranium (>1%) 

were stored in red drums. This material was used as a sweetener to increase the enrichment in 

the product. Standard production was 0.95% and 1.25% for Hanford. Special production orders 

for higher enrichments were made for other facilities, as requested and approved by DOE. The 

feed uranium compounds sent to Fernald were not chemically pure. Fernald products, however, 

were of excellent purity in order to meet strict requirements of the managers of the AEC 
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production reactors at various sites throughout the U.S. The product was evaluated by the 

collection of samples from the process stream. 

Fernald also received materials from the Savannah River Site (SRS), Hanford, Paducah Gaseous 

Diffusion Plant (Paducah), and Y-12 Plant in various forms. Fernald was responsible for taking 

the intermediate product and creating a final product. Cores returned from SRS came back 

containing crystallized material. Fernald became the repository for surplus uranium. They 

stored cladded uranium carbide and uranium alloys. 

The chemical forms of uranium handled at Fernald included uranium ore, UO3 (orange oxide), 

U3O8 (black oxide), UF6 (uranium hexafluoride), UF4 (green salt), diuranates (e.g., calcium or 

ammonium diuranate), UNH, UO2 (brown oxide), and uranium metal. The oxides were 

extremely insoluble. 

The Fernald site did not process U-233 or have it in pure form in any production processes. It 

was present in trace amounts in some of the uranium or thorium feeds. If present in thorium 

feeds, the concentration of U-233 could have increased in extraction liquids reused in the Pilot 

Plant. Material Accountablity kept track of the quantity of U-233 onsite. 

Recycled uranium introduced fission products and transuranics to the site. Fernald was not 

authorized and not set up to process plutonium materials. Trace amounts of plutonium (<10 ppb) 

were found in recycled uranium processed at the site, especially green salt. The Fernald process 

was not designed to handle plutonium. Engineering controls were based on uranium hazards and 

dust. There was plutonium embedded in the uranium that went airborne. The T-hopper 

operation filtration created a situation where there was a plutonium buildup. Plutonium Out of 

Specifications (POOS) was received and stored at Fernald for a period of time. NLO, Inc., did 

not attempt to maintain accountability for this material. Analyses for plutonium were made only 

on special occasions when the specific receipts of recycle material warranted such analyses. 

Thorium 

Thorium was associated with the Pilot Plant, Plant 9, the storage warehouses (Buildings 64 and 

65), Building 61, and some raffinate streams. Plant 9 was referred to as the Thorium Plant from 

the initiation of its operations. If this accurately described the operations in the plant, thorium 

work was probably here from the beginning of operations. Building 61 (Quonset Hut 2) was a 

storage area for ThO2 sintering and machining slugs. Fernald became the Thorium Repository 

and had the largest inventory of thorium in the United States at one time. 

Chemical forms of thorium handled at Fernald included ThO2 (light oxide), ThF4 crystals and 

solution, Th(OH)2 (sol gel); ThC2O4 (oxalate), thorium nitrate tetrahydrate, and thorium metal. 

There was high-fired thorium oxide created in the processes. Thorium gel was shipped in via 

railroad and pumped to the Pilot Plant when thorium operations were underway. 

Most of the stored thorium was located in Building 64 in white drums with blue rings. Site 

experts indicated the drums had noble gas labels on the outside. These drums eventually 

deteriorated and white powder, similar to soap powder, was seeping out of a subset of these 

drums. An over-packing campaign was initiated in the early 1990s to place the disintegrating 
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drums into burial boxes. The drums were dropped into a burial box and a lid bolted on the box. 

Cleanup of the loose thorium powder was also done. This campaign involved over 5600 drums. 

The thorium redrumming project involved remote handling of material with the use of fork lifts 

to put lids on the overpack containers. The Co-60 vault was also used for thorium storage. 

Radon 

There were roughly 4,000 grams of radium placed in the silos. This equates to 4,000 Ci, plus a 

similar amount of each of the daughters. This was the largest concentration of radium in the 

country. The majority of this radium was included in the K-65 residue; however, it is distributed 

throughout the silos. 

Health and Safety (H&S) was aware of the radon and thoron issues from very early on. Radon 

measurements were initiated for the dumping of drums in the 1950s, although the measurements 

were not routinely collected until much later. Radon monitoring started with the development of 

electronic radon monitoring devices. Eberline radon instruments (WLM-2s) with scintillation 

tubes were used at Fernald field radon measurements. If there was an inversion, this would 

cause issues because of the increase in ambient radon present. Later, E-perms and eventually 

Track-Etch detectors were placed around the silos for radon monitoring. 

Individual radon monitoring was done on a job-specific basis and not on a routine basis during 

the time Westinghouse was the contractor. Time-motion studies were done in the 1990s 

corresponding to Radon Measurements. The working level (WL) unit was implemented in the 

later years at Fernald. 

When individuals had to take samples or enter the silos, a glove bag was used to control 

exposure. The manhole on the top of the silo is opened and the sample is taken through the in 

and out port. There were attempts to measure radon in the glove bags, but these were not 

successful. 

The Communication Center received real-time radon concentration data. If this exceeded a 

trigger point (100 pCi/Liter), Security made an announcement asking individuals to stay indoors. 

A technician was dispatched to the area to verify the conditions. These announcements didn’t 

typically occur during the workday. This was a more current practice and did not occur in the 

1950s, 1960s, 1970s, and 1980s. 

The Radon Treatment System (RTS) was engineered to lower the radon levels in and around the 

silos. The system was composed of a large charcoal bed, PVC piping, and a fan. The idea was 

to blow the radon back into the silos. Significant gamma dose rates were measured at the 

charcoal filter of this system. Shielding was used to minimize exposure to the daughters. 

A Radon Control System (RCS) was put online during the remediation of Silos 1 and 2. The 

function of the system was collection of radon gas to reduce exposures. The systems in the 

mixer rooms of the treatment facility would become plugged, and they had to be unplugged. It 

was difficult to tell where the collection line was plugged, because there was no sensing 

equipment on the mixer line. The sensors available on the system would indicate everything was 

okay if at least one line was clear. Entry into this area resulted in exposures to radon gas. 
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Radon cups were placed on the fence line to monitor radon concentration. This began around 

1987 or 1988. The track-etch cups were changed out quarterly, and above background annual 

averages were noted at several locations near the K-65 Silos. 

There were two aerial surveys done at Fernald by EG&G. There was detectable gamma shine 

from the silos. Prior to 1986, the cloud of radon drifting from the silo area could be identified. 

General Radiological Control 

When Fernald began operation, the Health and Safety Division (H&S) included the Medical 

Department, the Industrial Hygiene and Radiation Department (IH&R), and the Fire Protection 

and Safety Department. Later, the Bioassay Laboratory Department was added. The first 

manager of the NLO H&S department was Dr. Joseph Quigley. He was working with the AEC, 

and was asked by the AEC to take the job as division manager and set up the health and safety 

functions at the new plant. The bioassay laboratory was also a part of the H&S Division. In 

1958, the site formed a Criticality Safety Department that was added to the H&S Division. The 

Fernald budget was based on the tons of material produced by the site. Although the budget was 

as high as 50 million dollars, limited funds were dedicated to safety. 

The current Radiological Control Organization consists of a field group matrixed to the projects 

and a central Radiological Control group that handles the programmatic implementation of the 

program. The field was matrixed to the project starting in about 1996. 

With the implementation of DOE Order 5480.11, the Radiological Control Program became 

more formalized and the Radiological Organization became centralized. When Westinghouse 

arrived, there was more communication with the workers and the public in relation to operations 

and safety hazards. The Radiological Control Program was generally improved. Following their 

release, Fernald implemented the DOE Radiological Control Manual and 10 CFR 835. 

Training primarily consisted of safety meetings held once a month during the NLO era. Workers 

reported that the meetings did not always focus on safety issues. With the change of contractors 

to Westinghouse, the first formal radiological worker training was implemented. There were two 

levels of Radiation Workers (Rad Workers) when the formalized training program was 

implemented; Rad Worker I and Rad Worker II. Rad Worker I was for workers who had a 

potential for exposure <2% Derived Air Concentration for U-238. These individuals were 

exempt from bioassay. Rad Worker II-qualified individuals had the potential to exceed this level 

and were required to participate in the bioassay program. 

Operating procedures contained safety requirements. The procedural requirements were 

determined by production (process steps) and H&S (safety requirements). 

During the NLO time period, there were less than 10 H&S technicians onsite. Initially the 

technicians served the entire plant. As more technicians were hired, they were assigned to 

particular areas. The early technicians were responsible for environmental monitoring, industrial 

hygiene, radiological control, and fire and safety. There was a shortage of technicians, making it 

difficult to cover both routine work and incident response. In the 1980s, the site started hiring 

more RCTs. Both project-specific support groups and a site-wide routines group were initiated. 
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When Westinghouse took over the Fernald site, they brought in more RCTs. All RCTs became 

subcontractors in February 2005, providing full coverage for all radiological areas. The increase 

in technician staff occurred in the 1990s after production had shut down and the site’s mission 

changed to environmental cleanup. 

Posting 

Historically, contamination areas were designated as Zone 1, Zone 2, or Zone 3 prior to the 

current posting requirements. Zone 1 had the least amount of contamination, while Zone 3 had 

the most contamination. There were additions and changes to postings starting in about the mid1980s. Workers started noticing an extensive increase in postings. The high-radiation areas 

included RTR, Building 65, the area around the dosimeter calibration source, parts of the RCS, 

parts of the TTA, and historically the silo domes. These locations were posted as a High 

Contamination Area, an Airborne Radiation Area, and a High Radiation Area. High-radiation 

logs are maintained. 

Engineering and Administrative Controls 

The principal engineering control for dust was to use dust collectors or scrubbers to ventilate an 

operation, and to remove dust before discharging the air out a plant stack. Dust of all sizes was 

collected; the efficiency for collecting large particles was greater than the efficiency for 

collecting smaller particles. A great deal of information about actual dust size in stack effluents 

is available in Fernald records. 

Dust collectors were changed when there was a change in the differential pressure or an 

indication that they were plugged. The bag house contained several bags with a blow ring 

connected to a vacuum hose. The material passing from the dust collector went into a hopper 

and then into a drum. Originally, the bags for the dust collectors were made of wool. Teflon 

eventually replaced wool. This was not very effective, and the seams had to be caulked so they 

would not leak as much. To replace the bags, the blow ring was removed and the 100-lbs bag 

was dropped in. During the replacement of the bags, the Chemical Operators would clean the 

hoppers. For this job, the individual would wear an extra pair of coveralls, but prior to about 

1978, they were not using respiratory protection. 

Portable shielding was used in the Rockwell Furnace area of the reduction process starting in 

about the 1960s. Heavy rubber mats were also used to reduce external exposure starting in about 

the 1960s. Additional shielding was added to the process area in the early 1980s, due to a rampup of production at this time. 

Several materials were tested as dust collectors to see which would hold up to collection of 

particulates best. Virgin wool was determined to work most efficiently. The particles deposited 

in the bags had sharp edges and would damage the bags over time. With significant damage, the 

dust bags would rupture and material was released from the stack. A lot of the released material 

deposited on the roof or the ground near the plant. There were two methods to identify reduced 

efficiency in the dust collectors. First, there was a differential pressure gauge, which was 

monitored by operations. When the differential pressure was outside acceptable limits, the dust 
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collector was changed. Second, there was stack monitoring with an audible alarm to alert 

personnel to releases. 

Prior to the addition of Bentonite to the silos, a layer of bentonite 2–4 ft thick was added on top 

of Silo material in about 1991 to prevent radon from escaping through cracks. Prior to this, there 

were dose rates above 100 mrem/hour. Personnel would burn out when working in the silo 

areas. After the Bentonite was added, the dose rates dropped to approximately 10 mrem/hour. 

There were some concerns that the material would lose its effectiveness as the bentonite dried 

over time. 

Starting with the arrival of Westinghouse, there were concerns about overexposure. They 

implemented a system where an employee was allowed to work a set amount of time per week 

on a particular job. The time limits were determined from dose rate measurements taken by a 

Radiation Monitor. When working on two jobs, the time limit for the second job may have to be 

reduced due to exposure received on the first job. For example, if an individual worked on a job 

where he received 50% of his allotted exposure, and the second job allowed him to work 

20 hours per week, he would have to reduce his time to 10 hours per week. It was the 

employee’s responsibility to keep track of the time limits. There were some individuals who 

didn’t know how to recalculate time limits as they went on to other jobs. Supervisors kept a 

daily log of work tickets each day. Although they collected the information, there was no formal 

review of this data. The time restrictions were assigned by job tasks. There was no policing of 

the time limits set for particular jobs. If an individual was not done with a job, he may keep 

working until it was completed. Time limits ranged from minutes to days per week on a 

particular job. 

Radiation Work Permits 

There were job-specific permits prepared by the IH&R Technicians. If it was felt a job was high 

risk (e.g., changing out dust bags), a technician would perform a survey and determine time 

limits for the particular job. These time limits were based on skin dose exposure most of the 

time. The original permits did not specify protective clothing or bioassay requirements. 

Respiratory Protection was specified for each task. 

Westinghouse initiated the modern version of the Radiological Work Permit (RWP). RWPs 

were implemented with the issuance of DOE 5480.11. Technicians prepared RWPs on a daily 

basis. Once per week, the RWPs were rewritten. Supervisors approved the RWPs. The older 

RWPs were similar to a fire permit. Requirements were based on process knowledge. Areas 

within the plants required RWPs; however, there was no RWP for general access. In about 

December of 1992, Work Planning and Radiological Compliance took over the responsibility for 

RWP preparation. Procedures for RWPs outlined the requirements for RWP issuance. Sign-in 

sheets were adopted in later years. 
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Field Instruments 

Portable survey instruments that have been used at FEMP include the following: 

• Ludlum Model 3 with beta/gamma pancake probes 

• Ludlum Model 12 with ZnS 

• Ludlum Model 2221 with ZnS in Scalar mode 

• Eberline RO-20 Ion Chambers 

• Bicron Micro-Rem Meters 

• AP2 Radon Discriminator – PIP’s detector by SAIC 

• HP-210 Frisker Probe 

• Portable Working Level Instrument 

For the Silos Project, the release criteria were set at 20 dpm/100 cm2 alpha. Smears were 

counted on a Ludlum 2221 Desktop Scaler for 5 minutes. The minimum detectable activity for 

this count is 8 dpm. In the calculation of activity, an area correction factor is applied. 

Prior to the early to mid-1980s, there was no particular survey frequency. Routine surveys were 

first adopted for administrative areas and break rooms. Neutron surveys were started in 4B, due 

to a request from a DOE Facility Representative. In 1995–1996, a study proved that there was 

no neutron hazard at the plant. There were criticality specifications implemented to prevent 

criticality accidents, and criticality safety alarms were present at Fernald. 

Air Monitoring 

Richard Heatherton was working for Health and Safety Laboratory (HASL) when he was asked 

to take the position of Manager of the Industrial Hygiene Department at the same time that Dr. 

Quigley was asked to become the H&S Division Director. Other HASL employees were sent, on 

loan, to Fernald, and they did much of the initial air monitoring as new operations were tested in 

the Pilot Plant or brought online. Dust studies of the various plants and jobs within those plants 

were conducted in the 1950s and 1960s, including Breathing Zone (BZ) and General Area (GA) 

sampling. Breathing zone air samples were taken based on the methodology implemented at 

HASL. This is not the same type of sampling as the current day Personal Air Sampler. 

Radiological Control concentrated their studies primarily on the Chemical Operations, because 

they were believed to have the highest potential for exposure. Generally, three samples were 

taken per task. The early method for collecting breathing zone samples consisted of holding an 

air sample pump with a 1” diameter filter paper as close to the nose of the worker as possible. 

Later, tubing was used draped over the shoulder and positioned at the lapel. The technician 

would follow the individual around with a stop watch to capture the exposure from each task. 

This included walking to the cafeteria. These types of annual air studies were discontinued in 

about 1968. Formal reports of these dust studies were issued. There was no routine air sampling 

in the 1950s throughout the facility. 

After the reduction in force in the 1970s, air sampling decreased. In 1989, Extensive Air 

Monitoring Plans were developed. Air sampling increased again in the 1980s, and was 

extensively used in the 1990s during the remediation of the site. About 1,000 BZ air samples 

were processed per month. The primary method for detection of isotopes other than uranium 
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was BZ air sampling. The air sampling was used instead of bioassay sampling. One hundred 

percent of the thorium workers wore BZ air samplers. Derived Air Concentration-hour tracking 

was implemented at Fernald with the extensive use of BZ monitoring in the 1990s. Air samples 

underwent a gross alpha/beta count, and if they were elevated, alpha spectroscopy was 

performed to identify the radionuclide of concern. There was a Personnel Air Sampling Card 

(Form 602-10-25) used to record internal exposure. 

In 1994, Field Radiological Control attempted to do a 12-hour, 24-hour, and 7-day decay count 

on air filters. An extrapolation was done on the initial counts to determine if there were issues. 

The filters would then be decayed up to 14 days and counted again. The counting responsibility 

was centralized, and air samples were forwarded to the Centralized Air Sample Counting group. 

Prior to this, samples were counted in the area and then results were forwarded to the Central 

group. 

The air monitoring program was required to support the internal dosimetry program. The 

internal dosimetry program requires 25% personnel air sampling use. This is described in the 

site Internal Dosimetry Technical Basis Document. 

Contamination Control 

Contamination control in the production areas was poor. At Fernald, it was common to see green 

salt, yellow cake, and black oxide on the floor in the production areas or on the plant road. Even 

though the floor was scrubbed once per shift, it was difficult to clean out the nooks and crannies. 

Releases and spills from equipment occurred routinely. Spills were commonly cleaned up with 

brooms. Operations in Fernald plants created a great deal of dust in the area. The production 

area was divided into a “hot side” and a “cold side.” There were administrative offices in the 

production areas. 

When individuals came to work, they came through the turnstiles, went to the locker room and 

put on company-issued coveralls and cloth caps, and went to work. At lunch time, employees 

showered and put on clean clothes. Workers had one pair of shoes that were to be worn in the 

production area, and another pair to be used in the clean areas. Contaminated shoes were worn 

into the clean areas (blue areas) of the site. After the work day was over, workers were just 

required to shower and change clothes before leaving the production areas. Prior to 

Westinghouse, there were no Radiation Monitors or monitoring machines around to determine if 

an individual had picked up contamination. Visitors were provided with smocks and shoe covers 

when entering the production areas. In later years, Personal Protective Equipment (PPE) ranged 

from none up to Level A protection. The Level A suits were wiped down and reused. PPE 

requirements were consistent for workers in the same immediate area by plan, but not necessarily 

enforced. 

The company cut the sleeves off the coveralls at one point, leaving their arms bare. Radiological 

Control found out about this practice and was not pleased. The company could not retrieve the 

sleeves to have them sewn back on. All these coveralls had to be disposed of and new coveralls 

procured. 
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The contamination monitoring improved when Westinghouse took over the site. Hand and foot 

monitors were introduced in some areas in the late 1980s/early 1990s. These units were not 

available in all areas. Fernald implemented hand and foot monitors around 1987. Hand and foot 

monitors were on the clean side of the change room. Personnel Contamination Monitors (PCMs) 

were put into service about 18 months later. PCMs were stationed at the doors in the locker 

room. PCMs were on the dirty side of the shower (process area to the service building). The 

alarm set points were based on the uranium contamination limits on the dirty side. The PCM 

count times were calculated based on the background radiation, and were determined 

automatically by the instrument. This made sure the count time was long enough to detect the 

prescribed alarm limit. There were daily occurrences of external contamination from radon with 

the initiation of egress monitoring. This was especially true when thermal inversions occurred. 

The individual was recounted after the radon was allowed to decay. They now use Passivated 

Implanted Planar Silicon detectors with energy discrimination set >5 MeV for monitoring. 

Laundry collected coveralls twice a day. The coveralls were often contaminated with orange 

oxide, green salt, black oxide, and yellow cake, exposing these workers to radioactive material. 

These individuals were not required to use respiratory protection. Site experts recollect that 

there was no airborne monitoring in the laundry area. 

Respiratory protection was optional in most cases, and use was intermittent. Initially, half-mask 

respirators were used. Respirators and/or filters were used more than once. Maintenance, 

operations, and others would wear their respirators around the neck. Frequently there was visible 

dust (e.g., green salt) on the respirator. Some individuals put Chem Wipes in the face piece of 

the respirator until the respirator was needed. When they were ready to use the respirator, they 

removed the Chem Wipes and donned the respirator. Other individuals just blew their 

respirators out prior to putting them on. Respirators were carried around in pouches or stored in 

lockers. It was also common in the early days to hang respirators on the machinery in case they 

were needed. Respiratory protection was not supplied to all areas. Prior to the implementation 

of a formal respiratory protection program, some individuals had respirators with a poor fit. 

It was common to use respiratory protection to reduce chemical exposure potential. For 

example, during the removal of radioactive asbestos in the laboratory, an airline respirator was 

used. Initially, the subcontractors had to supply their own respirators. Other respirators used 

included full-face respirators (starting in the late 1980s) and Positive Air Purifying Respirators. 

Initially, there was a multiple-use policy for respirators. It was not uncommon to wear a 

respirator around the neck in production areas, so it could be slipped on as needed for a particular 

job. Personnel would simply rinse the respirators out. Respirator surveys were not implemented 

at the time. In 1989, a single-use policy was adopted for respiratory protection use. 

In general, respirators were required during dusty conditions, such as drum dumping and certain 

maintenance activities (e.g., dust bag changes). It was up to the supervisors to enforce the 

wearing of respirators. In the case of the thorium overpacking, personnel wore a full-face 

respirator, a single set of Anti-Contamination clothing (Anti-Cs), and pencils. No respiratory 

protection was used during the reduction, gulping, cleaning of graphite molds, and machining. 

Machinists were not required to use respiratory protection, and were prone to exceeding 

monitoring action levels. Site experts noted that with the same operations where a respirator was 
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not used before, respirators were all of the sudden required. The change seemed to correspond to 

the arrival of Westinghouse. 

Historically, workers were instructed not to eat in the process areas. Some individuals 

disregarded these instructions and ate there anyway. This was identified by the RCTs as a big 

issue in the early years. Personnel were allowed to drink water in the area. In fact, there were 

multiple drinking fountains available. Personnel would chew tobacco or gum in the area. 

Smoking was allowed in the smoking areas set up in the production areas during NLO 

management. Employees were supposed to shower before lunch and change into their personal 

clothing. There was no requirement to shower prior to breaks. As a result, contamination was 

brought into the break rooms. Facility drinking water came from a deep aquifer of the 

groundwater. Both the shallow aquifer and the final drinking water were tested for 

contamination. Eating, drinking, and smoking were not allowed in contamination areas, highcontamination areas, radiation areas, and high-radiation areas after implementation of formal 

Radiological Control Requirements (e.g., 10 CFR 835). 

Truck drivers delivered brickets to the West Coast from Fernald. They would also retrieve 

empty containers on their way back to Fernald. There was a team of two drivers in the truck. 

Dose rate measurements were not routinely made in the cab area. Drivers were not directed to 

wear their dosimeters during transportation. The truck had Radioactive Material placards. 

External Dosimetry 

Initially, all personnel were assigned a dosimeter. The security and dosimetry badge were 

separate at the beginning of operations. In approximately 1960, the badges were merged, and 

everyone on site was monitored. At this time, the badge contained high-dose film, low-dose 

film, sulfur, and foils. Late in the 1980s, they started separating the dosimeter and security 

badge. During the period of time when the security credential was merged with the dosimeter, 

all personnel were monitored for external exposure. When the dosimeter and security credential 

were separated, all individuals entering the process area were required to wear a dosimeter. 

Dosimeters were required for the process areas; however, they were not required for the blue 

areas. With the implementation of 10 CFR 835, anyone who entered a posted area was assigned 

a dosimeter. If the area was 50 microrem per hour or greater, an area was posted with an insert 

indicating that a TLD was required. 

Dosimeters were taken home during some time periods and stored onsite for other periods. 

During the 1950s, the security badge was turned into security as an individual went through the 

turnstile. The employee received an identification card, which he/she would exchange in the 

morning for their security badge. There were about 8–10 Security Guards at the turnstiles at the 

time. The storage onsite corresponded to the period of time when dosimeters and the security 

credential were separate. At one time, badges were left in a rack at the guard post for a period of 

time. The dosimeter and security credential were retrieved when an individual came into work. 

Individuals were told to wear their dosimeter between the waist and neck. Dosimetry was worn 

on the outside of the garment. With the implementation of Anti-C’s, employees were instructed 

to wear their dosimeter inside of the Anti-C’s, where skin exposure was not a concern. RadCon 

did not police the use of dosimeters. Individuals would be questioned about not having the 

security badge, including the era where the dosimeters were combined with the employee badge. 
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Fernald was responsible for monitoring subcontractors onsite. Dosimeters (initially visitor 

badges) were assigned by the Security Department, but not all individuals were monitored. 

Badges could be assigned to more than one person for the monitoring period. Badges were read, 

but unless there was a positive reading, the dose was not tied to a particular individual. If the 

badge received measurable dose, an investigation into who wore the badge and where they 

worked was completed. Later, subcontractors entering radiological areas were assigned 

individual dosimeters. Years ago, subcontractors were treated differently than regular 

employees, and they believe this affected their radiation monitoring. 

The use of extremity dosimetry was fairly common with those who handled material. For 

example, uranium machinists were originally assigned wrist dosimeters, and later ring 

dosimeters. The site switched from the use of wrist dosimeters to ring dosimeters, which became 

standard issue for some jobs. When RWPs were implemented, the need for extremity dosimetry 

was specified in the RWP. Non-uniform exposure badges were not used, to the recollection of 

the site experts. Dose from surface contamination was calculated with Varskin in more recent 

years. There was no personnel neutron monitoring at Fernald. 

According to some site experts, there was non-uniform exposure to personnel in Plant 6 at the 

rolling mill area where the ingots were rolled out. There have been no issues with partial body 

exposure since 1994. Multiple badges were rarely used. The routine dosimeter was moved to 

the area of the body between the neck and the knee, where the highest dose rates were. 

Self Reading Pocket Dosimeters (SRPDs) were used in some areas, such as the thorium area. 

The field maintained an SRPD Issue Log. The initial and return readings (i.e., reading in and 

reading out) were recorded in the log. An investigation resulted if there were unusual results 

with SRPDs. The readings themselves are maintained with the field records. There were 

specific jobs, such as the roof repair on Plant 1, where individuals were instructed to wear 

SRPDs on other portions of their body (e.g., lower extremity). A comparison between the 

SRPDs and the primary dosimeter demonstrated that the results were generally within 30% of 

one another. Timekeeping was used to control individual external exposure for a particular job. 

There was an issue with contamination of badges. Green salt, orange oxide, and other materials 

would settle on the badge. In general, workers were told just to wipe the uranium off their 

badge. Badges were wrapped for a period of time to prevent contamination. Badges used in 

calibration were treated the same way. Baggies were used in cases where wet work was 

conducted. The dosimeter was surveyed by technicians during the badge exchange to make sure 

the badges were uncontaminated and could be sent to the processing laboratory. 

Dosimeter investigations date back to the 1950s. In cases where the dosimeter was lost, 

damaged, or showed suspicious results, an investigation was conducted. A temporary badge was 

assigned in the interim. An investigation form was provided to the individual’s supervisor to 

collect information on the exposure period, such as job task involvement. The average dose for 

each particular task was determined and the sum of doses from all tasks was determined. The 

technicians had a field procedure for assigning these doses. There is a code in the electronic 

system where doses were assigned based on this process. If the original badge were found, this 

information would be reflected in the dosimetry evaluation. Later, co-worker doses were used to 

assign dose for lost or damaged dosimeters. If the dosimeter was returned after it was lost, the 
 

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dosimeter was read; however, the co-worker dose was the dose of record. This was to account 

for the possibility that the dosimeter was not worn during a part of the monitoring period. If the 

investigation indicated a zero dose should be assigned, this was the dose of record. Investigation 

results were placed in the dosimetry file. 

There were dozens of investigations conducted on high skin doses. Individuals were asked what 

they had been doing and who they worked with for the given period of time. There was also an 

evaluation of the glow curve to determine whether an anomaly had occurred during the reading 

process. It was very clear from evaluation of the glow curve if reader difficulties had occurred. 

A hard copy of the glow curve was included in the employee file. 

Fernald contracted with the University of Michigan to irradiate badges with pure irradiation 

sources using low-energy betas and high-energy betas. They thought the two sources would also 

be representative of intermediate energy betas. At the time, they were using two elements to 

determine the beta dose at the site. An algorithm was developed and put into use at Fernald. 

They later discovered issues with the algorithm and hired the Idaho National Engineering and 

Environmental Laboratory (now INEL) to develop a revised algorithm for them. Upon 

completion, this algorithm replaced the previous algorithm. 

There was an overestimation of beta doses using the 802 TLD badges in the mid-1980s. 

Initially, this exposure was believed to be caused by contamination of the ledge in the holder 

adjacent to the E1 chip. As a result of collection of contamination on the badge holder, E1 

would be irradiated more than E2. This theory was discounted as the problem once the error in 

the algorithm was discovered. 

Historically, the Bioassay Laboratory Department was responsible for testing new dosimetry 

systems and processing dosimeters. Fernald was the first DOE site to receive accreditation under 

Department of Energy Laboratory Accreditation Program (DOELAP). Studies on angular 

dependence are documented in the DOELAP package created by Fernald. There are no negative 

dosimetry results in the dose of record. 

Fernald implemented an extensive area dosimetry program in the late 1980s/early 1990s. There 

was a wide distribution of these badges throughout the buildings. Area badges were changed on 

the same frequency as personnel dosimeters. 

Annual Radiation Reports were provided to the workers starting in the 1990s. The annual dose 

from the annual reports dropped for some workers in about 1996. The reason for this drop was 

not explained to the workers. [SC&A verified the drop in dose between annual reports.] There 

was no change in dose calculation methodology that would have resulted in a drop in cumulative 

exposure. 

Internal Dosimetry 

Individuals who were thought to have potential for internal exposure (e.g., work in airborne 

radioactivity areas) were monitored for internal exposure. There was a graded approach to the 

frequency of bioassay collection (i.e., monthly, bimonthly, or quarterly), based on the particular 

job title. Bioassay samples were also submitted upon hire and at termination. Radiation workers 
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submitted bioassay samples from the beginning of production. An individual was considered a 

radiation worker if they received 100 mrem or more of internal and external dose in a year. In 

general, Fernald erred on the conservative side and monitored individuals who did not need to be 

monitored. Notification cards were sent out when it was time to leave a urine sample. If they 

were not cooperative, they could be excluded from radiological areas. 

Fernald used the fluorometric technique originally developed by HASL to determine total 

uranium in urine. To obtain an isotopic analysis, samples were sent to an offsite laboratory. The 

best detection level achieved for fluorimetry was 0.005 mg/L. When the bioassay laboratory was 

moved outside the service building in the production area, the decision level was 0.015 mg/L. A 

trigger point of 0.05 mg/L was implemented for uranium bioassay. Kinetic Phosphorimetry 

Analysis was implemented in 1993 and Inductively Coupled Plasma/ Mass Spectroscopy in 

2002. The method for recording a “less than detection level” bioassay value was era-dependent. 

Zeros were recorded in the 1950s and 1960s, due to the limitations of the data processing 

equipment. Later, bioassay results were recorded as less than the detection limit. 

A neutron activation method, using the nuclear reactor at Wright Patterson Air Force Base, was 

eventually developed by NLO personnel for the determination of thorium in urine. However, 

there was no way to correlate the urine concentration with body burden. This problem went 

away when the mobile in-vivo counter became available in 1968. There was some breath thoron 

analysis utilizing the method developed by HASL. This was not a routine monitoring method, 

and there were no positive results. 

The first in-vivo counts were conducted in 1968 with the Y-12 Mobile in-vivo counter. The invivo counter visited Fernald twice per year. A permanent in-vivo counter was put into service 

around 1987. The focus of the in-vivo program was to measure the Maximum Permissible Lung 

Burden (MPLB). In-vivo counting was the bioassay method of choice for insoluble uranium and 

thorium. Counters were capable of detecting uptakes in the most exposed workers. Over the 

period of operation, there was only a single individual restricted for an extended period of time 

as a result of a high in-vivo count. There were situations where individuals were sent offsite 

(e.g., Hanford, Argonne National Laboratory) for follow-up counts. 

In-vivo counts were conducted after the employee’s weekend. The delay in counting was done 

to reduce the possibility of surface contamination on the individual. There was a tendency for 

protein-binding of the radioactive material to the body hair, especially in men. An additional 

reason for performing counts after the employee’s weekend was to allow particles deposited in 

the trachea to work their way up the respiratory system by cilia transport, and be swallowed. 

Radioactive material in the trachea would create erroneous results when trying to determine the 

activity in the lungs. There was no delay in the collection of urine samples. Dose was calculated 

in accordance with internal dosimetry procedures of the time, with any detectable amount on an 

in-vivo count. If the individual reached 75%–80 % of the MPLB, they were pulled off the job 

and special counts were completed. 

Other types of bioassay data collected at Fernald included chemical, thorium, radium, and later 

plutonium. Breath analysis was used to try to detect radon in breath. Although this data was 

collected, there was little faith in the results. These results may be documented in the weekly 

progress reports. There were two cases where in-vivo counting equipment detected positive 
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plutonium burdens. These individuals were sent to Chicago and Richland for in-vivo counts, 

which confirmed the uptake of plutonium. 

Studies on radon concentrations at Fernald were conducted in the 1999/2000 time frame. Radon 

Breath Analysis studies were conducted by NIOSH. Individuals were required to be off work for 

some period of time prior to participating. The results from this study indicated that Cincinnati 

had the 10th highest radon backgrounds in the nation. Pulmonary function tests were completed 

as a part of the study. There were a significant number of individuals taking the test that had 

circulatory or pulmonary health problems. 

With a suspected intake, individuals were requested to leave special bioassay samples, which 

could include urine and/or fecal samples. One sample was collected at the end of the shift and 

the other was collected the next morning. Follow-up bioassay samples were requested when an 

individual had a positive urine sample. Historically, trigger levels were used as a basis for 

requiring special bioassay samples. If anything off-normal occurred, employees were directed to 

leave a sample at the end of their shift and the beginning of the next shift. Codes associated with 

specific bioassay samples in the record indicate why the bioassay sample was taken (e.g., 

routine, special, etc.). After the implementation of DOE Order 5480.11, special bioassays were 

requested in the case of an incident or when a urine sample had a uranium concentration greater 

then 0.05 mg/liter. Any employee could initiate an Incident Investigation Form (IIF) if they felt 

they were exposed. They simply had to document the reason why they felt a Special Bioassay 

sample was warranted. The employee left a sample at the end of their shift and a second sample 

at the beginning of the next shift. In the early days, incident reports and urinalysis results were 

put into the medical record. 

Fecal sampling was used primarily as a special bioassay technique or for particular jobs. There 

was no routine sampling program in the early years. Baseline fecal samples were collected for 

workers involved in thorium work. Subsequent fecal sampling was incident-based. After the 

initial bioassay sample, air sampling and in-vivo counting were used as the primary means of 

bioassay for thorium. A background study using approximately 500 fecal samples was 

conducted in the mid-1980s to determine the background level of thorium in feces. 

Thorium workers were on a routine program to receive an annual in-vivo count. If there was an 

incident or a suspected intake, a special bioassay sample was taken. The emphasis for 

determining potential intake was based on BZ air sampling. After the thorium overpacking job, 

thorium-contaminated material was still handled. For example, work with the silo remediation 

potentially exposed personnel to thorium. Once the in-vivo counter was shutdown in 2002 or 

2003, the capability for thorium monitoring went away. There was also no program for sending 

individuals to other sites for routine in-vivo counting. 

The silos were built in the shape of a hemisphere. Silos 1 and 2 were surrounded by dirt, while 

Silo 3 was not. Silo 4 never held radioactive material. Each silo had a manhole to allow for 

continued monitoring and collection of samples. Most of the time, the silos were left alone. 

There was a sump between Silos 1 and 2 for collection of run-off material. No special routine 

monitoring requirements were implemented for work at the silos during production. During the 

remediation of the silos, Fernald implemented a more specialized bioassay for silo workers. 
 

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Subcontractors were not thought to be Radiation Workers and may not have had bioassays prior 

to 1986. Starting in the late-1980s, subcontractors were monitored based on the same criteria as 

permanent employees. Eventually, urine bioassay was collected bimonthly. Routine bioassay 

samples were followed with special bioassay samples when there was a positive result. Baseline 

thorium samples (fecal) were collected from individuals working in thorium areas. If an 

exposure was confirmed, an individual was moved to the “clean area” temporarily. 

Subcontractors were given an in-vivo count once per year or when ending work at the site. They 

were told if the count was positive or negative, but further explanations were not provided. 

Subcontractors did not participate in radon monitoring; however, there were times they were 

right on top of the source term. It was a challenge to get subcontractors to submit samples prior 

to them leaving. In later years, Fernald was required to send subcontractor dose reports to the 

employer (e.g., Wise, Rust Engineering, etc.) A good source of this information is the RadCon 

letter log. 

Technology shortfalls identified in the personnel-monitoring program were limited to the 

existence of extremely insoluble material. 

A field hearing was conducted with Senator Glenn as chair in about 1985. There was some 

concern raised over the background of the Y-12 in-vivo counter. During a congressional 

hearing, an independent Health Hygienist was asked to review the early body counts and explain 

the results. The reviewer could not understand the data. Former health physics staff indicated 

that the background of the in-vivo counter was well characterized, as quality control checks, 

including backgrounds, were completed on a regular basis and documented in logbooks. 

Environmental Monitoring 

The Environmental program involved air sampling, water sampling, soil sampling, biota 

sampling, and radon monitoring. Early in Fernald operations, gum papers were distributed to 

collect uranium fallout, and subsequently analyzed by the Bioassay Laboratory. This included 

an offsite-monitoring program. Radon monitoring was implemented in the 1980s. 

Environmental air monitoring stations were originally located in the four corners of the 100 acre 

production area. Stations were moved in the 1970s from the four corners of the production area 

out to the site boundary. Some of the stations at the production area boundary were kept in 

operation after the boundary fence-line stations were added. Offsite stations were added later. 

Air samples were collected and analyzed weekly. The number of air sampling stations increased 

over time, especially when the EPA became actively involved in reviewing the releases offsite. 

When the existence of trace materials in recycled uranium became an issue, the site shipped 

composite samples from each monitoring station to Oak Ridge National Laboratory to be 

analyzed for plutonium and neptunium. The results, published in the annual environmental 

report, indicated there was no issue with release of these radionuclides. 

From 1956–1969, microscopic techniques were used to collect particle size information. Particle 

size studies of the uranium processes were conducted in the 1980s. The particle size results from 

this study were consistent with the default value of 1.0 micron assumed by the site for 

environmental dose calculations. National Emission Standard for Hazardous Air Pollutants 
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made particle size determination a requirement for environmental monitoring. A report was 

issued on the elimination of nonrespirable particles in the 1960s or 1970s. 

The stack monitoring program was developed and initiated by the H&S Division to show the 

Production Division that uranium was present in some stack discharges, and that routine dust 

collector inspections by Production were needed. Thorium releases from the Fernald facility 

were also monitored and are documented in an historical emissions report published around 

1986. An accident involving a dust collector in Plant 9 occurred. Prior to the accident, there was 

little stack monitoring. After the accident, monitors were installed on the stacks on all 

production buildings. The original stack monitors were designed in-house. Strip charts recorded 

the releases from the stack to the environment. 

Large releases of material were the result of malfunctioning equipment or accidents. Releases 

were not deliberately made to the environment, although releases did occur. Fernald was 

investigated several times as a result of releases of dust to the environment. Uranium inventory 

was under tight control by the Material Accountability personnel at the site. 

There was an atmospheric release of UNH from Plant 2/3 over a period of weeks in the 

late-1980s/early 1990s due to a scrubber failure. There was detectable activity at air monitoring 

stations, which is documented in the Annual Site Environmental Report for that year. The 

release resulted in a shutdown of the refinery after the air sampling results were communicated 

to the Fernald management team. There was a shift in DOE policy on release to the 

environment. DOE did not effectively inform Fernald of this change. 

A release of uranium hexafluoride occurred at an operation in the Pilot Plant on February 14, 

1966. The Pilot Plant released approximately of 3,800 lbs of UF6, carrying it from the Pilot 

Plant, over the administration building and main laboratory, over the parking lot, and into the 

cow pasture. The site was not well prepared for this type of emergency at the time. This release 

was referred to as the Cutter release, and is formally documented. There was a large amount of 

bioassay samples collected around this time. 

Routine sampling of rivers, sumps, wells, etc., was performed. Fernald developed an Advanced 

Wastewater Treatment System to pump and treat water from the aquifer. Once it is treated, the 

water is released to the Great Miami River or injected back into the aquifer. The extraction wells 

were supposed to be free of contamination, although the wells were periodically found to be 

contaminated. There were indicators of contamination in the groundwater. The rain would fall 

on contaminated soil and migrate offsite, creating a plume. The source of groundwater 

contaminated was water that found its way to Paddy Run Creek through a sand lens and 

eventually down to the aquifer. 

Prior to construction of the Fernald plant, soil samples were made for engineering purposes, and 

groundwater flow rates were determined to evaluate water supply and quantity. In the 

remediation era, soil samples were conducted under the process buildings. During remediation, 

individuals were exposed to the contaminated soil after buildings were demolished. During soil 

remediation at Fernald, there were areas where the contamination went deeper into the soil than 

anticipated. 
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During the Shaw Project, soil was located into railcars and shipped to Envirocare. If the 

maximum acceptable concentration was not met, uranium metal would be thrown into the railcar 

as well. Site experts were uncertain whether Envirocare was aware of this practice. 

Until at least 1991, a Reuter-Stokes High Pressure Ionization Chamber was used for 

environmental radiation measurements. In addition, micro-R surveys were conducted. Since 

these measurements were easier to take, more Micro-R measurements were taken at each 

location. These measurements were taken to compare them with the Reuter-Stokes data. There 

was usually good agreement. In about 1991, environmental TLDs were also implemented to 

measure radiation levels in the environment. 

Once the radioactive material was placed in the silos, there wasn’t much of an issue with 

exposure to personnel. The silos were left alone, except that the grass around the silos had to be 

mowed, because there was a snake issue. This exposed individuals to radon from the silos. 

Individuals also found contaminated animals in the site buildings. 

Both episodic and routine releases are documented in the environmental report. There is a 

separate chapter addressing episodic releases. The most important episodic releases from an 

occupational standpoint were those that occurred inside the buildings, rather than to the 

environment. There have been no calculations of environmental dose to onsite workers to the 

knowledge of site experts. 

Dr. Quigley met with a representative of the Ohio Department of Health, and they agreed on 

limits for uranium, alpha and beta radioactivity, and fluoride in the Greater Miami River. There 

was also an agreement on how periodic reports would be made to the Ohio Department of 

Health. The local AEC office followed the lead of the Oak Ridge and Washington AEC offices 

in their dealings with local and state governmental agencies. If there was compliance with a 

state or local request, it was usually identified by the local AEC office in written documents as a 

matter of “comity.” The State of Ohio and Fernald periodically did split sampling (e.g., milk 

from cows grazing on Fernald property). Eventually, the state established a few offsite radonmonitoring locations. They also monitored air pollution parameters throughout the county and 

region, and did let Fernald co-locate some background radon monitors at one of their stations 

near the University of Cincinnati for a period of time. There were cooperative studies with 

Hamilton County. The county established its own radon monitoring locations. Fernald and the 

county shared data. 

Incidents 

The Communications Center was notified when there was a safety incident or unusual event. 

The Communications Center would, in turn, send emergency responders if there was a fire or if 

individuals were injured. During an incident, Security guarded the area. There were incidents 

(major and minor) almost on a weekly basis. 

There were IIRs that a worker could fill out if an anomaly had occurred. These were selfinitiating reports, with which workers could request special bioassay when they suspected an 

uptake. The technicians could also issue an IIR if they felt there was a possible intake. There 

were no formal trigger levels for special bioassay. The IIRs were filed in the employees 
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dosimetry file. Samples associated with incidents were analyzed and, if they were positive, there 

may have been a further investigation. The results of the investigation were communicated to 

the worker. If an incident resulted in the assignment of dose, a formal report was issued. If an 

injury occurred, a description of the injury and the treatment were documented in the medical 

file. If Fire and Safety responded, they also issued a report. Industrial Hygiene incidents were 

documented in letters to the division director. Other sources of incident information include 

urinalysis records, in-vivo counting records, and various ancillary records. 

Significant incidents had to be reported to the DOE or its predecessor within 24 hours of 

occurrence. The DOE would do an investigation of the incident. Corrective actions were 

determined during the investigation. The site also had internal reports, which succinctly 

described the incidents. Lessons learned were also developed throughout the complex and 

shared with other sites. Although Fernald per se did not maintain a database of these incidents, 

they were input into a database by DOE. 

Uranium fires occurred in Plants 5, 6, and 9 on a daily basis. When shavings or derbies would 

catch on fire, personnel would try to extinguish it by placing a shovel full of MgF2 over it, or by 

using fire or garden hoses to cool the drums. Type D Fire Extinguishers were added later. If the 

material continued to burn, a forklift driver would move the drums of burning shavings to a safer 

area. At times, the derbies continued to burn even after fire extinguishing efforts. At this point, 

they had to let the material burn. At times, derbies would catch on fire during the off hours. 

When the day shift came in, they found a pile of black oxide rather than a derby. During 

welding operations in Plant 8, a fire occurred in the northwest corner. 

Other incidents or unusual occurrences mentioned by site experts include the following: 

•	 On January 20, 1992, there was a fire at the Boiler Plant. Offsite emergency personnel 

were called in to assist with the situation. These individuals had to be escorted by 

Security. 

•	 Plant 4 shut down for 30 days, due to a spill involving plutonium in the late 1970s or 

early 1980s. 

•	 In Plant 9, there was an incident where a furnace kiln blew up. There were two fatalities 

as a result. 

•	 When operations cleaned the scales with a vacuum, there were occasions where the 

vacuum would blow up. 

•	 There were routine Rockwell furnace blowouts during the reduction process. Material 

would come out both the top and the bottom of the reaction vessel. Evacuation alarms 

would sound to alert workers in the surrounding area. Forklift personnel would remove 

the material immediately from the area and individuals went back to work. 

•	 There was an incident with the early radon treatment system, where they over-pressurized 

the silo, resulting in a radon release to the environment. 
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• There was a spill of orange oxide outside the north side of Plant 2/3 by the tank farm. 

There was a glove bag failure in Plant 9 in 1984. Workers called management when they noted 

that there was a release occurring at about 5:25 pm. The official report indicates that the release 

began at 6:00 pm. During the course of the investigation, witnesses of the release were not 

interviewed. The formal report indicates that 4 lbs of uranium were released to the atmosphere. 

Witnesses believe this was an underestimation. Several hundred pounds of black oxide fell out 

of the bottom of the silo High Efficiency Particulate Air filter, creating a large black mushroom 

that settled over the South Plant 9 cement pad. An investigation of excessive uranium emissions 

from Plant 9 was conducted by the Oak Ridge Operations Office. 

In 1985, during the night shift, an individual reportedly committed suicide in Plant 6 by 

immersing himself in a salt bath. There were no night shift operations at the time. The bath was 

covered with a metal top to keep the heat losses down. He was able to move the cover enough so 

that he could slide into the bath. Operations noted a blip in the salt bath temperature. On the 

surface of the salt bath was the outline of a person. The furnace was removed from operation 

and the contents of the bath were emptied after some cooling. They let the material solidify and 

crystallize in drums. When the bath had been emptied, they found remnants of metal. This 

incident resulted in a formal investigation by the local Sheriff’s Department. 

Poor Radiological Control Practices 

Radiation Safety rules were not always followed (e.g., not wearing respiratory protection). 

RadCon had to correct individuals through supervision when they were not adhering to the safety 

requirements. They were not allowed to redirect workers themselves. This changed as the 

Radiological Control Program improved. Some of the poor practices observed by site experts 

included the following: 

•	 Individuals sometimes turned the sensitivity of the alarms down, so the alarms would 

readily go off. 

•	 There was a situation where the electrical system was rewired, which affected the 

ventilation system in the area. 

•	 Badges were overexposed intentionally; however, these could be distinguished from 

others by the high doses, contamination of the dosimeter, and the darkened clear edges on 

the film. 

•	 Personnel would commonly sit on stacks of rods, derbies, or ingots. Originally they did 

not use rubber mats. Eventually they directed employees to put down a rubber mat 

before sitting on product. 

•	 Workers took breaks next to the silos on the hill. 

When unauthorized practices were observed (e.g., failure to wear appropriate PPE) in later years, 

the technicians were directed to issue a Radiation Deficiency Report or an Event Discovery 

Report. Depending on the severity of the event, disciplinary action could occur. 
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Miscellaneous 

Individuals were strongly encouraged to sign a form allowing the DOE to take samples postmortem for analysis. “You signed the form or you did not work,” was the reported attitude 

conveyed at the site. In 1981, a monetary incentive was offered to sign up for the registry. This 

was not effective with the workers. In 1984, workers were asked to authorize the use of their 

bodies upon hire for evaluation by the uranium registry. The authorization was not clearly 

explained, and individuals and their families did not realize the government could take the 

bodies. Some families would guard the bodies at the corners office to ensure the body or its 

organs did not disappear. For a period of time in the 1960s, there was a shortage of bodies for 

evaluation. 

When the Health Energy Radiation Branch of NIOSH was conducting a feasibility study on 

whether they could obtain data for an epidemiologic study, they concluded that the necessary 

information was not available. There was an absence or gaps in work history, exposure, and 

medical data at the time, limiting their ability to conduct accurate and comprehensive studies of 

remediation studies. 

The union questioned the integrity of the data at Fernald. Dr. Lynn Wise, a member of John 

Glenn’s staff specializing in environmental issues, visited Fernald with two assistants. On live 

television, the union presented Dr. Wise with supporting documentation that records had been 

altered. Examples of records provided were job orders, where stay times had been altered. This 

was one of the reasons NLO was fired. The situation is documented in congressional reports. 

The outcome was that some documents were determined to be altered. 

Following a congressional hearing in the mid-1980s, there was a change in the film badge 

program. Workers also question the discrepancies in dose results between themselves and 

collocated co-workers. 

Workers were told by supervisors that “the only way uranium could hurt you was if it fell on 

your head.” 

Medical 

Medical exam frequencies have changed over time at Fernald. Many site experts remembered 

receiving an annual physical at one time. During medical exams, individuals submitted urine 

and blood samples for medical evaluation. Routine bioassay samples were collected at the time 

of the annual physical. Each individual was seen by a doctor. Initially, subcontractors were not 

provided with medical exams and x-rays. Later, medical x-rays were provided every other year. 

According to some site experts, NLO lost some of the worker medical records in the 1970s. 

Limited information was known regarding the x-ray units. Medical x-ray units were surveyed by 

the RCTs in the past. The Food and Drug Administration has also done inspections. 

Audits and Assessments 

The New York Operations Office Health and Safety Representative conducted annual 

assessments of the Radiological Control program for the first few years. These audits were 
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ad hoc at first, but became more formal by the end of the 1950s. Fernald fell under the 

jurisdiction of the Oak Ridge Operations Office, who conducted semi-annual to annual audits of 

all safety program areas. During the mid-1980s, the site had one audit after another. The 

Defense Nuclear Facility Safety Board completed a Program Review Audit at this time. Oak 

Ridge Operations office and DOE headquarters also performed audits of the overall safety 

program. Eventually, the Ohio Field Office became responsible for conducting assessments of 

Fernald. Audits included evaluations of Environmental Monitoring, Industrial Hygiene and 

Radiation, Fire Protection and Safety, and Criticality Safety. 

Other Hazards 

Radiological hazards were not the only health hazards individuals encountered at Fernald. In 

addition to radioactive material, beryllium, mercury, asbestos, and lead were also used on the 

site. Some of the chemicals used in the processes included ammonia, nitric and hydrofluoric 

acids, degreasers, solvents, magnesium fluoride, etc. There were pounds of Be handled at the 

Pilot Plant. Beryllium was used as a coating for the ingot mold and crucibles, similar to a 

nonstick coating on a frying pan. Asbestos was reported as prevalent in many of the plants. 

There were releases of hydrogen fluoride into the work area and environment. When opening a 

system, it was not uncommon to get sprayed with hydrofluoric or nitric acid. Workers were 

exposed to nitric acid and hydrofluoric acid fumes, and sometimes overcome by these fumes. 

Acid burns were not uncommon, and some workers eventually developed chemical dermatitis. 

Plant 6, Plant 7, and Building 13 had issues with bird droppings, causing a health hazard. 

At Plant 2/3, they would release rust-colored material to the environment. Transportation 

personnel were asked not to park the trucks in the general area of Plant 2/3, especially at the 

truck dock. Plant 9 also released nitric acid to the environment. Releases also occurred from the 

Pilot Plant, the Tank Farms, and Plant 4. Workers indicated that the material would burn their 

lungs and sometimes their skin. 

Hoppers had seals that would breach, releasing hydrofluoric acid and product. This was 

particularly a problem when the product got low. Alarms for this type of release were not 

consistent, and at times did not work or did not sound. If the workers visually saw the clouds, 

they would exit the area. There was no guidance given for re-entry. If they were able to breath, 

individuals would re-enter the building. 

A beryllium surveillance program exists; however, it is not inclusive of all individuals potentially 

exposed to beryllium at Fernald. There have been positively diagnosed cases of Berylliosis in 

Fernald workers. Some bioassay sampling was completed prior to and after lead jobs. 

There were also industrial safety hazards at Fernald during both the production and remediation 

era. For example, there were problems a couple of times during remediation with vehicles 

(dozers and trucks) falling into the pits. 

Technical Basis Document Comments 

Several comments were made by site experts concerning the NIOSH Fernald TBD. 
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•	 The NIOSH TBD is based on urine, air monitoring, and dosimeter results. These values 

may not be representative of the exposure conditions. 

•	 NIOSH/ORAU has been provided with Plant-by-Plant process information. 

•	 Tables of projected exposures to employees in the NIOSH TBD include a 

Decontamination Factor (DF) for many operations, based on use of a respirator. There is 

no indication of when the DF is applied. Workers, particularly those working prior to the 

mid-1980s, indicate that respirators were rarely used. Consequently, the potential 

exposures in the TBD may be underestimated. 

NIOSH held a worker outreach meeting in November 2003. The TBD was completed March 

2004.