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

February 26, 2008 

Mr. David Staudt 

Center for Disease Control and Prevention 

Acquisition and Assistance Field Branch 

Post Office Box 18070 

626 Cochrans Mill Road – B-140 

Pittsburgh, PA 15236-0295 

Re: Contract No. 200-2004-03805, Task Order 1: Document No. SC&A-TR-TASK1-0026, 

Draft Review of Battelle-TBD-6001, Site Profiles for Atomic Weapons Employers That 

Worked Uranium And Thorium Metals, Revision FO Dated December 13, 2006 

Dear Mr. Staudt: 

In accordance with Contract No. 200-2004-03805, Task Order 1, SC&A is pleased to submit the 

Draft Document No. SC&A-TR-TASK1-0026, Draft Review of Battelle-TBD-6001, Site Profiles 

for Atomic Weapons Employers That Worked Uranium And Thorium Metals, Revision FO Dated 

December 13, 2006. This document has been reviewed for Privacy Act information, edited 

accordingly, and is cleared for unrestricted distribution. 

 If you have any comments or questions, please contact me at 732-530-0104. 

Sincerely, 

John Mauro, PhD, CHP 

Project Manager 

cc: P. Ziemer, PhD, Board Chairperson D. Sundin, NIOSH 

Advisory Board Members A. Makhijani, PhD, SC&A 

L. Wade, PhD, NIOSH H. Behling, PhD, MHP, SC&A 

C. Branche, 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 

C. Ellison, NIOSH T. Bell, Saliant 

L. Shields, NIOSH Project File (ANIOS/001/26) 

 
Draft 

ADVISORY BOARD ON 

RADIATION AND WORKER HEALTH 

National Institute for Occupational Safety and Health 

Draft Review of Battelle-TBD-6001, 

Site Profiles for Atomic Weapons Employers 

That Worked Uranium And Thorium Metals, 

Revision FO Dated December 13, 2006 

Contract No. 200-2004-03805 

Task Order No. 1 

SCA-TR-TASK1-0026

Prepared by 

S. Cohen & Associates 

1608 Spring Hill Road 

Suite 400 

Vienna, Virginia 22182 

Saliant, Inc. 

5579 Catholic Church Road 

Jefferson, Maryland 21755

February 2008 

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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Document No. 

SCA-TR-TASK1-0026 

Effective Date: 

Draft — February 26, 2008 

S. COHEN & ASSOCIATES: 

Technical Support for the Advisory Board on

Radiation & Worker Health Review of 

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

Draft Review of Battelle-TBD-6001, 

Site Profiles for Atomic Weapons Employers That 

Worked Uranium And Thorium Metals, 

Revision FO Dated December 13, 2006

Page 2 of 52 

Task Manager: 

________________________ Date: ___________ 

William Thurber 

Project Manager: 

________________________ Date: ___________ 

John Mauro, PhD, CHP 

Supersedes: 

N/A 
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TABLE OF CONTENTS 

Acronyms and Abbreviations ..........................................................................................................5 

Executive Summary.........................................................................................................................6 

Review of Battelle-TBD-6001, Discussion of Findings..................................................................8 

1.0 Purpose and Scope (Section 1.0) .........................................................................................9 

2.0 Introduction (Section 2.0) ....................................................................................................9 

3.0 Uranium Dosimetry (Section 3.0)......................................................................................12 

3.1 Source Terms for External Doses (Section 3.4).....................................................13 

3.2 Internal Dosimetry (Section 3.5)............................................................................13 

4.0 Process Description (Section 4.0).....................................................................................16 

5.0 Occupational Medical Dose (Section 5.0) .........................................................................19 

6.0 Occupational Environmental Dose (Section 6.0)...............................................................19 

6.1 Environmental External Radiation (Section 6.1)...................................................20 

6.2 Environmental Internal Dose due to Inhalation and Ingestion of Radioactive 

Material (Section 6.2) ............................................................................................21 

6.3 During Operations (Section 6.2.1).........................................................................21 

7.0 Occupational External Dose (Section 7.0).........................................................................22 

7.1 Submersion in Contaminated Air (Section 7.1.1)..................................................22 

7.2 Exposure from Contaminated Surfaces (Section 7.1.2).........................................22 

7.3 Process Specific Dose Rates (Section 7.2) ............................................................23 

7.4 Drum Doses (Section 7.3)......................................................................................24 

7.5 Summary of External Doses Received by Workers During Operations 

(Section 7.4)...........................................................................................................24 

8.0 Occupational Internal Dose (Section 8).............................................................................25 

8.1 Process Specific Uranium Air Sampling Data (Section 8.2) .................................25 

8.2 Resuspension during Periods with No Uranium Operations (Section 8.3)............36 

8.3 Time-Dependent Air Concentration Data (Section 8.4) ........................................36 

8.4 Summary (Section 8.5) ..........................................................................................40 

9.0 Minor Comments and Typographical Errors .....................................................................42 

10.0 References..........................................................................................................................44 

Appendix A: Tables 12 and 13 from ORAUT 2005.....................................................................46 
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LIST OF TABLES 

Table 1. Air Sampling Results from Digestion Operations ................................................ 10 

Table 2. ICRP Default Dose Conversion Factors (Sv/Bq inhaled for adult workers) ........ 14 

Table 3. Comparison of MCW Plants 4 and 6 Average Exposure and Range Values 

with those Reported in C&H 1960........................................................................ 29 

Table 4. Comparison of Lognormal Distribution Parameters for MCW Plants 4 and 6 

with TBD-6001 Lognormal Parameters................................................................ 29 

Table 5. Comparison of Estimated Average Exposure from 1942 to 1958 with C&H 

1948 to 1956 Average Exposure........................................................................... 30 

Table 6. Comparison of Estimated Average Exposure from 1942 to 1958 with 

C&H 1948 to 1956 Average Exposure ................................................................. 31 

Table 7. Comparison of Year-Specific Correction Factors from TBD-6001 Table 

8.28 with Correction Factors Derived from 1948 to 1956 Trend Line................. 40 

LIST OF FIGURES 

Figure 1. Flow Diagram for Uranium Refining from Ore or Concentrates ......................... 11 

Figure 2. Comparison of C&H Tabulated Lower End of Range with 

Mallinckrodt Plants 4 and 6 Lower End of Range................................................ 32 

Figure 3. Comparison of C&H Tabulated Upper End of Range with 

Mallinckrodt Plants 4 and 6 Upper End of Range ................................................ 32 

Figure 4. Comparison of C&H Tabulated Average Exposure with 

Mallinckrodt Plants 4 and 6 Average Exposure ................................................... 33 

Figure 5. Comparison of TBD-6001 Lognormal Median with Mallinckrodt Plants 4 

and 6 Lognormal Median...................................................................................... 33 

Figure 6. Comparison of TBD-6001 Lognormal GSD with 

Mallinckrodt Plants 4 and 6 Lognormal GSD ...................................................... 34 

Figure 7. Comparison of TBD-6001 Lognormal 95th Percentile with 

Mallinckrodt Plants 4 and 6 Lognormal 95th Percentile ....................................... 34 

Figure 8. Comparison of Estimated Average Exposure (dpm/m3) from 1942 to 1958 

with C&H 1948 to 1956 Average Exposure (dpm/m3)......................................... 35 

Figure 9. Comparison of Estimated Average Exposure (dpm/m3) from 1942 to 1958 

with C&H 1948 to 1956 Average Exposure (dpm/m3

)......................................... 35 

Figure 10. TBD-6001 Table 8.27 Mean Air Concentrations from 1948 to 1956, with 

Extrapolation to Earlier and Later Years and Regression Trend Line (n=9, 

R2

=0.78)................................................................................................................ 38 

Figure 11. Comparison of TBD-6001 Table 8.28 Year-Specific Correction Factors 

with Factors Derived from 1948 to 1956 Trend Line........................................... 39 
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ACRONYMS AND ABBREVIATIONS 

AEC Atomic Energy Commission 

Advisory Board Advisory Board on Radiation and Worker Health 

AMAD Activity Median Aerodynamic Diameter 

AWE Atomic Weapons Employer 

BZ Breathing Zone 

DCF Dose Conversion Factor 

dpm Disintegrations per minute 

DWA Daily Weighted Average 

EU Enriched Uranium 

FMPC Fernald 

GA General Area 

GSD Geometric Standard Deviation 

IMBA Integrated Modules for Bioassay Analysis 

MCW Mallinckrodt Chemical Company 

NIOSH National Institute for Occupational Safety and Health 

PL Preferred Level 

RU Recycled Uranium 

SX Solvent Extraction 

TBD Technical Basis Document 

TIB Technical Information Bulletin 

UF4 Uranium Tetrafluoride 

UF6 Uranium Hexafluoride 

WLM Working Level Month 
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EXECUTIVE SUMMARY 

In accordance with direction provided by the Advisory Board on Radiation and Worker Health 

(Advisory Board) during the Advisory Board conference call held on November 27, 2007, this 

report presents a review of Technical Basis Document-6001, Site Profiles for Atomic Weapons 

Employers that Refined Uranium and Thorium (Battelle-TBD-6001, Revision F0, December 13, 

2006), referred to here as TBD-6001. TBD-6001 provides a generic dose reconstruction 

exposure matrix specifically for workers at Atomic Weapons Employer (AWE) facilities that 

performed uranium refining operations and have no or limited site-specific external dosimetry, 

bioassay, or air-sampling data upon which to base site-specific/realistic dose reconstructions. A 

companion document to TBD-6001 is TBD-6000 (Site Profiles for Atomic Weapons Employers 

that Worked Uranium and Thorium Metals [Battelle-TBD-6000, Revision F0, December 13, 

2006]), which provides an exposure matrix for workers at AWE facilities that performed 

uranium metal-working operations. SC&A’s draft review of TBD-6000 was delivered to the 

National Institute for Occupational Safety and Health (NIOSH) and the Advisory Board on 

September 14, 2007 (SC&A 2007). As will be discussed subsequently, some of the issues raised 

in our review of TBD-6000 are equally relevant to our review of TBD-6001. 

From our review of TBD-6001, we have developed the impression that this document was 

hastily prepared. The document contains numerous typographical errors and other editing issues 

that make the logic used in developing the dose rates difficult to follow and may hamper the use 

of the document by dose reconstructors. The construction of the primary dose summary tables is 

confusing, and little effort is made to lead the reader through the methodology used in 

developing these summary tables. The sources of numerous pieces of technical data are not 

referenced. We have provided a listing of some of these editorial issues separate from our 

technical findings. 

The following technical findings are discussed in subsequent sections of this report. 

Finding 1: It is not possible to judge whether the basic approach to developing inhalation doses 

in TBD-6001 is claimant favorable, based on the information presented in that document. 

However, based on analyses presented in this review, it appears that the average inhalation doses 

used in TBD-6001 are not claimant favorable, particularly for the period prior to 1948. 

Finding 2: TBD-6001 oversimplifies the process descriptions from Christofano and Harris 

(1960) and, as a result, may have missed or understated significant pathways for external and 

internal exposure. 

Finding 3: The approach used in TBD-6001 to calculate the contribution to external exposure of 

contaminated dust settled on workplace surfaces is not appropriate. SC&A addressed the same 

issue in its review of TBD-6000 (SC&A 2007, Item 5). 

Finding 4: Summary Tables 7.1 and 7.3 in Section 7 of TBD-6001 that address external 

exposures require additional elaboration to understand the sources of the contained data and how 

the data were derived. 
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Finding 5: The approach taken by NIOSH to develop year-specific correction factors to 

inhalation doses does not appear to be claimant favorable. Doses in the early years may be 

understated. 

Finding 6: NIOSH did not consider radon exposures in developing inhalation exposure rates. 

Since pitchblende ore contains significant quantities of Ra-226 and its progeny, this omission 

significantly understates inhalation exposure rates for workers involved with operations at the 

front end (ore processing) of the refining process. 
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REVIEW OF BATTELLE-TBD-6001, DISCUSSION OF FINDINGS 

During the conference call of the Advisory Board on Radiation and Worker Health (Advisory 

Board) held on November 27, 2007, the Board directed SC&A to perform a review of Technical 

Basis Document (TBD) 6001, Site Profiles for Atomic Weapons Employers that Refined 

Uranium and Thorium Metals (Battelle-TBD-6001, Revision F0, December 13, 2006). This 

report presents our review of TBD-6001. SC&A was not directed to review the appendices to 

TBD-6001 as part of this review. 

An overarching issue that must be considered is the basic approach to reconstructing doses 

adopted in TBD-6001. The fundamental question that must be asked is this: Is the sampling 

data in Christofano and Harris 1960, which is the basic source document used to develop the 

exposure matrix in TBD-6001, adequate to characterize worker exposures over the period 1948–

1956 for which data are provided, and can the exposures be extended back in time to 1942? 

Christofano and Harris note that 60 surveys were made at 7 plants over a 9-year period. This is 

less than one survey per plant per year on average. Each survey establishes the conditions in the 

plant over a brief survey period of a few days’ duration. This survey is then assumed to be 

representative of the conditions for the balance of the year or for longer time periods in some 

locations. Operations, particularly in the early days of the Manhattan Project, could hardly be 

described as steady state. There was continuing pressure on production staffs to maximize 

output from plants originally designed for short-term operation, and process excursions were 

common. We believe that the NIOSH report needs to provide a carefully reasoned basis for 

accepting this fundamental premise, namely, that relatively short-term surveys performed in a 

given year in a given facility are representative of the entire year’s operation and protective of 

the claimant’s interests. 

Regarding such additional justification, we also note that the authors of the Harshaw TBD 

concluded the following: 

It has been determined that it is not feasible to perform dose reconstructions from 

August 14, 1942 through November 30, 1949 due to lack of internal dosimetry 

data for the radionuclides associated with uranium operations at Harshaw

(ORAUT 2007, p. 23). 

If such a conclusion is appropriate for Harshaw, why would it not be equally appropriate for the 

generic workers covered by TBD-6001? TBD-6001 includes no internal dosimetry data, and 

relies solely on air sampling to estimate internal exposures. 

The discussion that follows is organized according to the major sections that comprise 

TBD-6001 and uses the same section numbering scheme (in parentheses). We consider this a 

focused review, because we did not attempt to assess each and every guideline or look-up table. 

Rather, we limited our review to those analyses, guidelines, and look-up tables that we judged to 

be potentially important to the dose reconstruction process. In some cases, the TBD discusses 

different aspects of a given exposure pathway, such as external dosimetry, in separate chapters. 

As a result, there is some redundancy in presenting the results of the review. Those sections of 

TBD-6001 for which we have no comments are not listed in the discussions that follow. 
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1.0 PURPOSE AND SCOPE (SECTION 1.0) 

NIOSH states in this section that the report provides the technical basis for reconstructing doses 

for AWE sites that refined uranium under government contract during the period 1942–1958; 

however, no basis is provided for selecting 1942–1958 as the relevant time period. We also note 

that NIOSH refers elsewhere to 1944 as start date (page 4, second paragraph). 

2.0 INTRODUCTION (SECTION 2.0) 

Section 2.0 of TBD-6001 is a brief introduction to the NIOSH report noting that, in the early 

days of the Atomic Energy Commission (AEC) program, no one organization had the capability 

of performing all the steps necessary to process uranium ores and produce uranium metal billets 

or uranium hexafluoride (UF6) needed to manufacture fuel for the production reactors. The 

authors of TBD-6001 state that they relied heavily on a journal article by Christofano and Harris 

(1960)1 to develop the exposure matrix. Christofano and Harris, who worked for the AEC 

Health and Safety Laboratory, accumulated more than 20,000 air-sampling measurements in 60 

surveys at 7 AEC plants over the period 1948 through 1956 (C&H 1960, p. 77/441). They also 

provide some information on external exposures. The uranium refining operations were 

conducted at Middlesex, Mallinckrodt (MCW), Fernald (FMPC), Harshaw, Linde, Electromet, 

and Vitro. By 1955, uranium refining was consolidated into two parallel integrated processing 

plants— MCW and Fernald (with the exception of uranium hexafluoride production, which was 

moved from Harshaw to Oak Ridge). NIOSH has prepared individual TBDs for MCW, FMPC, 

Linde, and Harshaw (ORAUT 2004, 2005, 2006, and 2007). 

C&H present tabular summaries of air-sampling measurements for the various unit operations 

involved in uranium refining, including ore sampling, digestion, denitration, oxide conversion, 

UF4 production, uranium metal production, uranium metal recasting, UF6 conversion, scrap 

recycling, and drum handling, but not for solvent extraction.2 For each unit operation (except 

solvent extraction), the tabular summaries provide minimum, maximum, and average air 

concentrations (dpm/m3) from breathing zone (BZ) measurements associated with various 

worker activities required by each of the unit operations and from general area (GA) samples. 

The tables also provide an “average daily exposure.” As an example, Table 3 from C&H 1960, 

included here as Table 1, summarizes the air sampling results for the digestion operation.3 In the 

digestion operation, pitchblende ore or ore concentrates are dissolved in nitric acid, and the 

uranyl nitrate solution is separated from the gangue by filtration. If the uranium-bearing solution 

resulted from processing of pitchblende ore, it was further processed to remove radium. A 

simplified flow diagram for all the uranium refining operations is included as Figure 1. 

 1

 Since Christofano and Harris (1960) is frequently referenced throughout this review, we have chosen to 

use the abbreviation C&H or C&H 1960 for simplicity and readability of our review. 2

 Although solvent extraction was discussed, no tabular data summary was provided. 

3

 C&H refer to the summary values in Table 3 as “average daily exposure.” In other tables in C&H 1960, 

terms such as “DWA” (Tables 5 and 10), “average weighted exposure” (Table 4), “daily average exposure” 

(Table 2) and “weighted average exposure” (Tables 6 and 8), “weighted average” (Table 9), “average exposure” 

(Table 11), and “daily weighted average” (Table 1) are used. We presume these terms are synonymous (and, 

apparently, they are assumed to be synonymous in TBD-6001), but we are not sure. 
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Table 1. Air Sampling Results from Digestion Operations 

(Source: C&H 1960, Table 3) 

Pitchblende Ore (dpm/m3) Concentrates (dpm/m3) Sample Location Range Average Range Average 

BZ reaming ore chute 350–8,000 1,000 

BZ drum dumping – uncontrolled 2,500 1,000–6,000 2,400 

BZ drum dumping – ventilated 0–220 90 

BZ drum dumping – remote 6–44 30 

BZ lidding and delidding drums 600–1,700 1,200 

GA digest area 6 – 330 150 0–75 30 

GA ore room 90–2,600 1,000 

Average daily exposure 7–350 110 17–100 40 
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Figure 1. Flow Diagram for Uranium Refining from Ore or Concentrates 

(Based on C&H 1960, Figure 3) 

Pitchblende Ore Concentrate 

Nitric Acid 

Gangue

Hydrogen 

F2 Anhydrous HF 

Mg Chips 

MgF2

 Sampling 

 Digestion 

Radium Removal 

Solvent Extraction 

Denitrification 

Oxide Reduction 

UF4 Conversion 

UF6 Conversion U Metal Production 

U Recasting 

Nitric Acid 

Recovery 

H2SO4

BaCO3

RaSO4

BaSO4 Cake

Solvent to Recovery 

Raffinate to Disposal 

(Th-234 & Pa-234x)
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No discussion is provided in C&H 1960 as to how the range and the average of the “Average 

Daily Exposures” reported in their tabular summaries were obtained, and the paper includes no 

references that would assist the researcher in understanding how these quantities are derived. 

Presumably, the data are some type of long-term average from 1948 to 1956 of time-weighted 

daily averages of surveys taken for various operations from the seven plants. Unfortunately, 

there is no transparency as to how the average of the average daily exposures is derived. 

For example, NIOSH uses the average airborne concentration value of 110 dpm/m3

 from Table 3 

of C&H 1960 to establish a median exposure level of 49 dpm/m3 (Table 8.3) and a median daily 

inhalation rate for a digester operator in summary Table 8.29 of 145 pCi/calendar day based on a 

40-hour work week. In our opinion, the method used to derive this exposure rate is as follows 

(although the NIOSH document does not make clear the calculational approach): 

I (pCi/day) = 49 dis/min-m3 × 1 min/60 sec × 1 Bq/dps × 27 pCi/Bq × 1.2 m3/hr × 8 hr/day × 

250 work days/365 calendar days = 145 pCi/calendar day. 

However, the larger problem is that there is no insight into how the core value of 110 dpm/m3

was derived originally. Without additional insight into the averaging processes used by C&H, 

one cannot make any assertions as to whether or not the approach used in TBD-6001 for this 

inhalation value is reasonable and/or claimant favorable. This issue is further discussed under 

Section 8.1 of this report. 

This lack of transparency as to how C&H manipulated their survey data is also apparent in 

Figure 16 of their paper. Figure 16 is a plot of weighted exposures (dpm/m3) by year. The plot 

contains 137 data points (17 in 1948, 9 in 1949, etc.). C&H provide no information as to how 

their survey information was composited to obtain the 137 annual data points. The information 

in Figure 16 was used in TBD-6001 to develop year-specific correction factors (see TDB-6001, 

Table 8.28). During dose reconstruction, these correction factors are to be used as multipliers of 

the inhalation intake rates in Table 8.29, depending on the years during which a claimant was 

employed. Since it is not known how the C&H survey data were composited to obtain annual 

weighted exposures, it is not possible to judge whether or not the approach used is claimant 

favorable. 

It should also be noted that C&H 1960 covers the period 1948–1956, while the relevant period 

for dose reconstruction using TBD-6001 is 1942–1958. The ramifications of this will be 

discussed subsequently in Section 8.3 of this report. 

3.0 URANIUM DOSIMETRY (SECTION 3.0) 

Section 3 of TBD-6001 presents a generic description of the characteristics of uranium and its 

emissions, and a general discussion of the types of external and internal exposures that are 

associated with uranium refining operations; it also treats dose conversion factors (DCFs). Most 

of the information in Section 3 (i.e., Sections 3.1, 3.2 and 3.3) of TBD-6001 is the same as the 

information included in Section 3 of TBD-6000, which was previously reviewed by SC&A 

(SC&A 2007). In its review of TBD-6000, SC&A found the fundamental descriptions of the 
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isotopic composition of various forms of uranium to be correct. The same conclusion applies to 

TBD-6001. 

3.1 Source Terms for External Doses (Section 3.4) 

SC&A provided an extensive critique of the information in Section 3.4.2 of TBD-6000 (SC&A 

2007, Section 3.1, Surface Contamination). The same comments are relevant to Section 3.4.2 of 

TBD-6001. In particular, SC&A questioned the use of a model for developing surface 

contamination based on settling of 5 micron (AMAD) particles with a terminal settling velocity 

of 0.00075 m/sec onto external surfaces. 

 

3.2 Internal Dosimetry (Section 3.5) 

The only sources of internal exposure considered in TBD-6001 are the various isotopes of 

uranium and the uranium progeny that exist 100 days after ore processing. The report does not 

explicitly address exposures to Th-230, Ra-226, or Rn-222 and its progeny. These radionuclides 

could be important for workers that handled ore. For example, consider an air sample collected 

in an ore processing area, and it is determined that the sample contains x dpm/m3

 after allowing 

the short-lived radon progeny to decay away. This sample is likely to contain equal activities of 

all isotopes that comprise the natural uranium decay series, except radon and its short-lived 

progeny. By assuming that all the detected alpha emissions are U-234, when in fact the sample 

likely contains equal amounts of U-234, U-238, Th-230, and Ra-226, is it possible that the 

derived doses to specific organs might be significantly underestimated? Table 2 presents the 

default ICRP 50-year committed dose equivalent (Sv/Bq inhaled) to key organs for these 

radionuclides (ICRP 1968). 
Effective Date: 

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Table 2. ICRP Default Dose Conversion Factors (Sv/Bq inhaled for adult workers) 

 U-238 U-234 Th-230 Th-230 Ra-226 

 Type F Type M Type S Type S Type M Type S Type M 

 

Time after intake 50 years 50 years 50 years 50 years 50 years 50 years 50 years 

 

Adrenals 3.00E-07 1.20E-07 1.50E-08 8.70E-09 1.60E-06 1.50E-07 3.00E-08 

Bladder Wall 3.00E-07 1.20E-07 1.50E-08 8.70E-09 1.60E-06 1.50E-07 2.90E-08 

Bone Surface 8.70E-06 3.50E-06 4.60E-07 2.70E-07 1.50E-03 1.40E-04 9.00E-06 

Brain 3.00E-07 1.20E-07 1.40E-08 8.70E-09 1.60E-06 1.50E-07 2.90E-08 

Breast 3.00E-07 1.20E-07 1.50E-08 8.70E-09 1.60E-06 1.50E-07 2.90E-08 

Oesophagus 3.00E-07 1.20E-07 1.50E-08 8.70E-09 1.60E-06 1.50E-07 2.90E-08 

St Wall 3.00E-07 1.20E-07 1.50E-08 9.20E-09 1.60E-06 1.50E-07 2.90E-08 

SI Wall 3.00E-07 1.20E-07 1.60E-08 1.00E-08 1.60E-06 1.50E-07 3.00E-08 

ULI Wall 3.00E-07 1.30E-07 2.10E-08 1.70E-08 1.60E-06 1.50E-07 4.10E-08 

LLI Wall 3.00E-07 1.30E-07 3.30E-08 3.20E-08 1.70E-06 1.70E-07 8.00E-08 

Colon 3.00E-07 1.30E-07 2.60E-08 2.30E-08 1.60E-06 1.60E-07 5.70E-08 

Kidneys 3.10E-06 1.30E-06 1.70E-07 1.00E-07 2.20E-05 2.10E-06 4.30E-08 

Liver 1.20E-06 4.80E-07 6.20E-08 3.70E-08 1.90E-05 1.80E-06 1.30E-07 

Muscle 3.00E-07 1.20E-07 1.50E-08 8.70E-09 1.60E-06 1.50E-07 2.90E-08 

Ovaries 3.00E-07 1.20E-07 1.50E-08 8.70E-09 1.20E-05 1.10E-06 2.90E-08 

Pancreas 3.00E-07 1.20E-07 1.50E-08 8.70E-09 1.60E-06 1.50E-07 2.90E-08 

Red Marrow 9.10E-07 3.70E-07 4.90E-08 2.80E-08 5.20E-05 4.90E-06 6.40E-07 

ET Airways 3.00E-07 5.20E-06 3.10E-05 7.50E-05 1.40E-05 7.40E-05 1.30E-05 

Lungs 3.10E-07 2.20E-05 6.70E-05 4.10E-05 1.70E-05 4.00E-05 1.70E-05 

Skin 3.00E-07 1.20E-07 1.50E-08 8.70E-09 1.60E-06 1.50E-07 2.90E-08 

Spleen 3.00E-07 1.20E-07 1.50E-08 8.70E-09 1.60E-06 1.50E-07 3.90E-08 

Testes 3.00E-07 1.20E-07 1.50E-08 8.70E-09 1.20E-05 1.10E-06 2.90E-08 

Thymus 3.00E-07 1.20E-07 1.50E-08 8.70E-09 1.60E-06 1.50E-07 2.90E-08 

Thyroid 3.00E-07 1.20E-07 1.50E-08 8.70E-09 1.60E-06 1.50E-07 2.90E-08 

Uterus 3.00E-07 1.20E-07 1.40E-08 8.70E-09 1.60E-06 1.50E-07 2.90E-08 

Remainder 3.30E-07 1.40E-07 3.10E-08 3.80E-05 1.90E-06 2.00E-07 3.50E-08 

Effective dose 5.00E-07 2.90E-06 8.00E-06 6.80E-06 2.80E-05 7.20E-06 2.20E-06 

As may be noted, for Th-230 and Ra-226, the limiting DCFs for several organs are greater than 

or comparable to that for U-234. Hence, ignoring the fact that some of the alpha activity 

observed in an air sample might be Th-230 or Ra-226 could result in a substantial underestimate 

of the dose to certain organs. TBD-6001 should address possible exposures to Th-230 and Ra226 for workers handling ore. 

The report also does not address exposures to enriched uranium (EU) or recycled uranium (RU). 

In light of this, Section 1 of the report, titled “Purpose and Scope,” should make it clear that this 

document should only be used for workers involved in the processing of uranium ores and 

concentrates, and that it does not provide direction regarding exposures to workers who might 

have handled EU, RU, or ores containing Th-232. 

With respect to the possible importance of exposure to radon and its progeny, it is important to 

recognize that an air particulate sample will not capture radon. In addition, it is likely that the 
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short-lived progeny that are captured in an air sample will be allowed to decay before alpha 

counting. In order to assess the possible significance of ignoring radon and its short-lived 

progeny in TBD-6001, we reviewed a number of source documents, including NYOO 1949, 

ORAUT 2005, and ORAUT 2007. It is reported on page 8 of NYOO 1949 that radon levels 

exceeding 1 × 10-10 Ci/L were experienced by workers loading and unloading freight cars. That 

document further notes that at the Middlesex plant, “For a period of several years employees 

engaged in this operation [loading and unloading freight cars] were exposed to levels of radon 

which ranged from 200 to 250 times the ‘maximum permissible exposure’ of 10-10 c per liter” 

(NYOO 1949, p. 14). C&H 1960 states that radon concentrations in ore cars were as high as 10-7

to 10-8 Ci/L. 

 

A table of radon exposures at MCW Plant 6, where ore storage and handling, digestion solvent 

extraction, and denitration operations were conducted, is presented on page 71 of ORAUT 2005. 

The table, which covers the period 1946–1957, includes radon exposure rates for a variety of job 

descriptions. The exposure for a production operator is stated to have been 0.138 WLM per 

month worked, based on an equilibrium factor of 0.25. Based on a breathing rate of 9.6 m3/day, 

this translates to an exposure of 5.3 × 105

 pCi/day. 

As may be noted in Table 8.29 in TBD-6001, uranium intake rates are provided for a broad range 

of operations, job titles, and years of AEC operations. The table does not address radon. For 

example, the recommended uranium inhalation rate for an ore digestion operator is 1.45 × 

102 pCi/d. This corresponds to a 50-year dose commitment of about 4 mrem per day of exposure 

(145 pCi/day × 6.8E-06 Sv/Bq [U-234 eff. dose] × 1 Bq/27 pCi × 1E05 mrem/Sv). Assuming 

the whole-body dose equivalent associated with exposure to radon and its progeny is about 

200 mrem/yr per pCi/L of radon,4 the daily whole-body dose equivalent associated with a radon 

intake rate of 5.3 x105 pCi/work day is about 10 mrem/work day (5.3E05 pCi/day × 1 day/9.6 m3

× 1 m3

/1000L × 200 mrem/yr per pCi/L × 1 yr/8760 hr × 8 hr/work day). Clearly, failure to 

consider radon exposure could result in underestimating inhalation exposures for workers 

involved in ore handling and processing, and residue handling and processing. This may involve 

not only workers directly involved in those operations, but also nearby workers performing other 

operations. TBD-6001 should address the issue of radon exposures, or at least caution the dose 

reconstructor that radon exposures are not included in the TBD. 

A review of the exposure matrix prepared by NIOSH in support of dose reconstruction of 

workers at the Harshaw Chemical Company (ORAUT 2007) reveals that consideration was 

given to radon exposures, RU, EU, radium, thorium, special isotopic separations, and incidents. 

Since TBD-6001 is designed as a generic protocol for uranium processing facilities, some 

mention of these isotopes is warranted. 

 4

 Tables 2.4 and 2.1 of NCRP Report No. 93 (NCRP 1987) indicate that the typical radon exposure to 

people in the U.S. of about 1 pCi/L (this includes a collective average for both indoor and outdoor exposure) is 

associated with a whole-body dose equivalent of about 200 mrem/yr (including progeny). Hence, using this as a 

rule of thumb, exposure to radon plus progeny is associated with an effective whole-body dose of about 0.5 mrem 

per full day of exposure per pCi/L of radon in partial equilibrium with its progeny. 
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4.0 PROCESS DESCRIPTION (SECTION 4.0) 

This section of TBD-6001 divides uranium refining into nine unit operations, as follows (see also 

Figure 1): 

• Ore digestion 

• Solvent extraction 

• Boildown and denitration to produce UO3

• Oxide conversion to produce UO2

• Conversion of UO2 to UF4 by hydrofluorination 

• Reduction of UF4 to uranium metal in a magnesium thermite bomb 

• Recasting of uranium metal into billets for further fabrication 

• Conversion of UF4 to UF6 by fluorination 

• Scrap recovery 

Descriptions of the various worker activities are drawn by NIOSH from simplified process 

descriptions in C&H 1960. We have concerns that this heavy reliance on process descriptions in 

C&H 1960 may result in understating some worker exposures. Examples are provided here. 

Ore Handling 

On page 15, Section 4.1 of TBD-6001, NIOSH defines the first refining step as “ore digestion.” 

However, C&H (1960) indicate that an ore sampling step preceded ore digestion. Sampling 

involved opening welded drums, drying, crushing, screening, and other handling operations. Per 

Table 1 of C&H 1960, the daily weighted average for manual sampling of pitchblende ores was 

800 dpm/m3

, and 140 dpm/m3 for automatic sampling. Cleaning ore drums resulted in BZ 

exposures averaging 30,000 dpm/m3. 

In addition, in Table 33 of ORAUT 2005, NIOSH notes that external exposures related to ore 

handling in Plant 6 of MCW ranged from 7 to 200 mR/hr, based on measurements made in 1947 

and 1948. C&H also commented on external exposures experienced by sampling plant operators 

handling pitchblende ores. These authors note that exposures in areas where drums of highgrade ore were stored were 10 to 100 mR/hr at 10 feet (C&H 1960, p. 77/441). High external 

exposures could also be experienced by truck drivers moving drums of ore between locations. 

Depending on the details of the plant layout, workers in other operations might also be affected 

by stored drums. The authors of TBD-6001 should explain why ore sampling exposures were 

not included in that document. 

Digestion 

The authors of TBD-6001 note in Section 4.1 (page 15, second paragraph) that removal of 

radium from the digester liquor by co-precipitation with barium sulfate produced drums of waste 

with high gamma radiation. C&H (1960, p. 81/445) indicate that exposures of 100 to 300 mR/hr 

were measured at the surface of a 55-gallon drum of radium cake, and exposures of 50 to 

100 mR/hr were measured at a distance of 10 ft from a stack of radium cake drums. 
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The process used for radium removal at MCW is described somewhat differently in ORAUT 

2005 (Section 4.1). At MCW, sulfuric acid was added to the uranyl nitrate solution from the 

digester to precipitate out radium sulfate (called K-65 residue) that was then removed via a 

string-discharge rotary vacuum filter. Residual sulfate from the uranium-bearing solution was 

then removed by the addition of barium carbonate that precipitated barium sulfate. The barium 

sulfate was separated by centrifugation. According to Table 32 of ORAUT 2005, exposures 

from an array of 95 drums containing K-65 residue ranged from 95 mR/hr at 1 foot to 9.4 mR/hr 

at 30 feet. Additionally, both types of residues (K-65 and barium sulfate cake) were reworked 

for uranium recovery by MCW—an additional source of exposure (SC&A 2005, Finding 7, 

p. 25). 

Drums of K-65 residue produced at locations such as MCW were often stored at Middlesex. 

Thus, workers at Middlesex received external exposures from both radium-bearing pitchblende 

ores and K-65 residues. For the 3-month period from November 1948 through January 1949, the 

average beta/gamma exposure (65% gamma) was 330 mrep/week, but 10 employees had 

exposures exceeding 50 R, and the highest exposure for the period was 110 R (NYOO 1949, 

p. 13). Workers involved in ore digestion could experience comparable external exposures. 

Workers at MCW were exposed to 100 g/month of radium in ores and residues (NYOO 1949, 

p. 19). 

Measurements of external exposure of workers around ore digestion tanks at MCW Plant 6 were 

frequently above tolerance (100 mR/8 hr or 12.4 mR/hr) (ORAUT 2005, Table 33). However, 

the authors of TBD-6001 assume an exposure to penetrating radiation of 6.1 mR/hr (Table 7.1) 

for a digestion worker, based on proximity to a single drum of pitchblende concentrate. 

Based on this type of information, NIOSH should re-examine the basis for estimating external 

exposures at the front end of the ore refining process. 

Solvent Extraction 

 

In the solvent extraction process (Section 4.2, p. 16), the authors of TBD-6001 note that, after the 

uranium is stripped from the aqueous phase, the aqueous raffinate contains nitrates of all 

undesirable metals, including Th-234 and Pa-234m. According to C&H (1960), this raffinate 

may be concentrated and calcined to recover nitric acid with the residue stored in drums at the 

plant or discarded directly to lagoons. It is likely that the concentrated raffinate would be a 

strong source of beta emitters. It is not apparent that this exposure source was considered in 

TBD-6001. Table 7.1 lists no non-penetrating exposure to the hands for solvent extraction 

operators. 

C&H 1960 (p. 80) notes that overhead process piping in operating areas had an internal coating 

that caused an exposure of about 300 mrem/week. Based on a 48-hr work week, this source 

would contribute an additional 6 mrem/hr, presumably in the ore digestion and solvent extraction 

(SX) areas. It is not apparent that this external radiation source was considered in developing 

Table 7.1. 
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Oxide Reduction 

The oxide reduction process is outlined in Section 4.4. As noted there and in C&H 1960, the 

orange oxide (UO3) produced in the denitration step was a coarse, lumpy material requiring size 

reduction prior to conversion to UO2. To accomplish this, operators dumped material from 

drums into a mill, where a fine powder was produced. In all likelihood, this was a very dusty 

operation, but C&H 1960 does not provide air-sampling data for this operation. However, airsampling data for milling at MCW include weighted average concentrations of 12,600 dpm/m3

and 46,200 dpm/m3 for measurements made in 1948 (ORAUT 2005, Table 13). In Section 8.2.4 

(pp. 40–41), NIOSH discusses internal exposures from the oxide reduction operations. The 

oxide reduction operations assume average weighted exposures or daily weighted averages 

(DWAs) of 20,000, 700, and 140 dpm/m3

 for tray furnace, multiple hearth, and horizontal reactor 

operations, respectively (TBD-6001, Table 8.9). While it is possible that dust exposure from the 

milling operations would be captured by the statistical distribution of DWAs for tray furnace 

operations, the same cannot be said for using multiple hearth and horizontal reactor DWAs to 

capture dust exposures from the milling operations. 

Hydrofluorination 

The hydrofluorination process is described in Section 4.5. The hydrofluorination of UO2 to 

green salt at Harshaw produced about 2,000 grams per day of residue containing 2.5 curies of 

Th-234 and Pa-234m. This resulted in whole-body beta radiation exposures of about 1 R/week 

for as long as 3 years (NYOO 1949, p. 58). The exposure of 1 R/week (200 mR/day) can be 

compared with the exposure to a hydrofluorination operator with a median non-penetrating 

radiation exposure to the body (other than hands) of 122 mrem/day (or a 95th percentile exposure 

of 1,722 mrem/day), based on a 40-hr work week (TBD-6001, Table 7.3). It thus appears that 

the approach in TBD-6001 adequately captures the exposure effects of Th-234 and Pa-234m in 

green salt residues for the Harshaw plant through early 1949. 

Uranium Recasting 

In reviewing this section, we used a general rule of thumb that the external beta/gamma exposure 

rate at contact with pure uranium metal is about 200 mR/hr, and the penetrating exposure rate at 

1 foot from the surface of a large piece of pure natural uranium metal is about 2 mR/hr. We 

obtained these values from previous MCNP calculations performed by SC&A. In addition, the 

rule of thumb for contact exposure rate is consistent with the values in Table 3.4 of TBD-6001. 

Recasting of uranium metal into billets is described in Section 4.7. Recasting is done in vacuum 

furnaces and, during the melting process, Th-234 and Pa-234m (which are in approximate 

equilibrium with the U-238) volatilize and are condensed on the cooler surfaces of the furnaces. 

Workers involved in furnace charging, discharging, cleaning, and maintenance were subject to 

high levels of beta radiation (NYOO 1949, p. 12). NIOSH has selected a value 665 mrem/hr for 

non-penetrating radiation (to body parts other than skin) for a recasting furnace tender (TBD6001, Table 7.1). This value was reportedly taken from ORAUT 2005 (Table 33, p. 234), which 

lists the beta exposure for “recasting, furnace tending” as 665 mrep/wk (not per hour). Other 

exposures reported in Table 33 for recasting workers in Plant 4 at MCW include the following: 
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• Recasting, top furnace tending – 1,220 mrep/wk 

• Recasting, bottom furnace tending – 800 mrep/wk 

 

Apparently, the value of 665 mrem/hr is a typo. This typo also appears to be present in Table 7.1 

of the TBD. 

NIOSH used a value of 665 mR/hr (Table 7.1, p. 29) for exposure of the uranium recasting 

furnace tender to penetrating radiation, citing the same reference as for non-penetrating radiation 

discussed above (i.e., ORAUT 2005, Table 33, p. 234). A careful re-examination of this value 

and whether the temporal basis is hours or weeks is particularly important, since the use of 

665 mR/hr results in the highest exposure from materials handling for any operator listed in 

Table 7.3 (i.e., 816 mR/day for a 40-hour work week). A dose reconstructor faced with the need 

to select a value for exposure to penetrating radiation for a worker with no clear cut job 

description might chose this maximum value as claimant favorable. While such a selection 

would indeed be claimant favorable, it appears to be erroneously high. 

 

Fluorination 

The fluorination process is outlined in Section 4.8. Air concentrations for fluorination (UF6) 

production are presented in Table 8.21 of TBD-6001. The maximum value of the DWA entries 

in this table is 7,300 dpm/m3 (for hex loaders). Both hydrofluorination and fluorination 

operations were conducted at the Harshaw Chemical Co. It is noted in Table 8 of NYOO 1949 

that average daily exposures measured at Harshaw exceeded 8,750 dpm/m3 (125 PL × 

70 dpm/m3 per PL)5 in 34% of the measurements. Based on Figure 11 of NYOO 1949, it can be 

presumed that this included worker(s) with exposure(s) of 9,800 dpm/m3 (140 PL), worker(s) 

with exposure(s) of 13,160 dpm/m3

 (188 PL), worker(s) with an exposure(s) of 15,120 dpm/m3

(216 PL), and worker(s) with exposure(s) of 26,180 dpm/m3 (374 PL). The 24 workers with the 

highest exposure (26,180 dpm/m3

) were hex area loaders. Thus, it does not appear that the data 

used by NIOSH adequately capture the range of exposures for operators working in the 

production of UF6. 

 

5.0 OCCUPATIONAL MEDICAL DOSE (SECTION 5.0) 

The approach to occupational medical dose is the same as provided in TBD-6000 (Battelle 

2006). This approach had been previously reviewed by SC&A and found to be scientifically 

sound and claimant favorable (SC&A 2007). 

6.0 OCCUPATIONAL ENVIRONMENTAL DOSE (SECTION 6.0) 

This section of TBD-6001 discusses occupational exposures to workers away from the main 

operating areas. 

 5

 PL is the preferred level for alpha-emitting dust averaged over an 8-hr work day. At that time the PL was 

70 dpm/m3

. 
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6.1 Environmental External Radiation (Section 6.1) 

As described in Section 6.1.1 (page 23, second paragraph), NIOSH assumes that the ambient 

dust level is 7 dpm/m3 for non-operational work areas while the plant is operating, and that 

uranium particles with a 5-μm AMAD fall from this dust for a full year at a terminal settling 

velocity of 7.5E-04 m/s to floors in the workplace. This surface contamination then remains 

with no cleanup. The same general methodology is used in Section 7.1.2 to calculate 

occupational exposures, except that work place air concentrations are used rather than the default 

value of 7 dpm/m3 for non-operational areas. Some of our concerns with the approach used to 

develop surface contamination levels were presented previously in our review of TBD-6000 

(SC&A 2007, Item 5). 

While the assumption of a 5-μm AMAD is often used for calculating inhalation doses, it is of 

questionable relevance when calculating surface contamination levels. In Section 4.1 of TBD6001 (page 15, third paragraph), NIOSH states the following: 

The uranium ore was a powder, often 20 mesh (Christofano and Harris (1960)). 

Twenty mesh powder has a diameter of 840 μm (Lide 1995, pp. 15–37). If 840 μm 

is assumed to be the upper 99%ile of the aerosol particle size distribution, the 

equations of ICRP-66 (ICRP 1994) would imply that the actual AMAD of the 

aerosol is about 54 μm. 

Alternatively, if one assumes that the geometric standard deviation (GSD) for the particle size 

distribution is 5, as suggested in Section 2.1.2.5 of Strom (2007), then the median particle size 

for the distribution would be about 20 μm. From Figure 5-80 of Perry and Green (1984), the 

terminal settling velocity for a 20-μm particle with a density of 10 g/cc is 0.12 m/sec. This 

would cause the deposition factor used in TBD-6001 to calculate surface contamination to be 

low by more than 2 orders of magnitude. 

In its review of TBD-6000, SC&A raised some concerns about the use of an air concentration of 

7 dpm/m3

 for non-operational areas of a plant (SC&A 2007, Section 5). We further note here 

that exposures to workers in non-operational areas may be higher than that. For example, the 

following weighted average values have been reported (ORAUT 2005, Table 20): 

• Dispensary: Nurse/Medic/Other (personnel) – 1.5 to 175 dpm/m3

• Office: MCW – Clerk/Maintenance/Messenger/Porter/Expediter – 15 to 50 dpm/m3

• Office: MCW – Other, AEC-all AEC except Engineer – 0 to 50 dpm/m3 

Any use of a default air concentration for non-operational areas should provide some guidance as 

to what should be considered “non-operational areas of the plant.” Use of a value of 7 dpm/m3 

would not be appropriate for the types of locations cited above. 

 
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6.2 Environmental Internal Dose due to Inhalation and Ingestion of Radioactive 

Material (Section 6.2) 

In its review of TBD-6000, SC&A questioned the general approach to calculating ingestion 

exposures (SC&A 2007, Finding 7). SC&A noted the following: 

Internal doses associated with the inadvertent ingestion of uranium are derived in 

the TBD using models and assumptions that have been discussed with NIOSH in 

the past as part of the review of numerous site profiles and exposure matrices. 

Based on these discussions, it is our understanding that NIOSH would agree that 

the basic methodology described in the TBD is deficient and should be revised 

when the revised methodology is developed. 

 

Assuming that the revised methodology is developed, the following discussion would become 

irrelevant. NIOSH states the following in Section 6.2 (pp. 23–24): 

At several DOE facilities, radioactive emissions from plant stacks have been 

known to significantly increase the ‘background’ radiation levels on the plant 

site. The estimate of 7 dpm/m3 used in Section 6.1.1 can be assumed for the 

contamination level. Ingestion intakes were found using the equation I IMBA = 

3.062 ×10−5 Ah as discussed in Section 8.5.3. 

In this equation, IIMBA is the IMBA chronic intake in pCi/d, A is the air concentration (pCi/m3), 

and h is the number of working hours in a year. If the measured air concentration has units of 

dpm/m3, then one must divide the constant in the above equation by 2.22 (dpm/pCi). 

However, according to Section 8.5.3, the daily ingestion rate is given by the equation IIMBA = 

3.373 × 10-5 Ah, and the incidental hand-to-mouth ingestion rate is given by the equation IIMBA = 

3.425 × 10-5 Ah, and the total ingestion rate by the equation IIMBA = 6.798 × 10-5 Ah. In spite of 

what the text in Section 6.2 says, the equation IIMBA = 6.798 × 10-5 Ah apparently was used to 

calculate the inhalation doses in Table 6.2. The direction provided in TBD-6001 appears 

contradictory and should be corrected. 

6.3 During Operations (Section 6.2.1) 

Further confusion as to the intent of Section 6.2 is created by the second paragraph in 

Section 6.2.1, where NIOSH states the following: 

An estimate of the intake from the inhalation pathway can be estimated assuming 

an airborne contamination level, a breathing rate, and daily exposure period. 

The estimate of 1 dpm/m3

 can be assumed for the contamination level. A 

breathing rate of 9.6 m3

/d includes an exposure period of 8 hours per day. A 

conversion factor of 2.22 dpm/pCi must also be employed, to give a daily intake of 

4.4 pCi/d of uranium. 
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Why is a contamination level of 1 dpm/m3

 used when the reader had previously been advised 

that the contamination level was 7 dpm/m3 and 7 dpm/m3 was used to develop Table 6.2? 

Additionally, the cited intake 4.4 pCi/d is for one 8-hr working day, while the exposures in 

Table 6.2 are adjusted for calendar days. This paragraph seems to be irrelevant. 

7.0 OCCUPATIONAL EXTERNAL DOSE (SECTION 7.0) 

Section 7.0 of TBD-6001 presents guidance in the form of default exposure rates for 

reconstructing external doses to workers from several exposure pathways, including submersion 

in contaminated air, standing on contaminated surfaces, and standing in the vicinity of, or 

handling drums containing uranium product produced during, uranium refining operations. The 

default exposure rates are provided in three tables, Tables 7.1, 7.2, and 7.3, all of which were 

compiled based on film badge data and process knowledge taken from actual uranium 

processing facilities, and also external dosimetry computer codes. In developing these tables, the 

data cited in C&H 1960 and ORAUT 2005 were used. The dose rates are cited in the TBD as 

representative of “typical” conditions in the workplace at uranium refining facilities. 

7.1 Submersion in Contaminated Air (Section 7.1.1) 

The external exposure submersion dose rates provided in Table 7.3 are apparently based on a 

combination of assumed airborne dust loading (dpm/m3

) of alpha emitters and the DCFs in Table 

3.9 of the TBD. Some explanation is needed regarding the airborne dust loadings employed and 

the rationale for their use. In Section 7.2 of the TBD, reference is made to C&H 1960 as the 

source of the airborne dust loading data. However, it is not apparent what data was specifically 

used and where that data came from. The TBD appears to be rushed, making it difficult to 

review. For example, for ore handling operations, was any consideration given to the 

contribution of Ra-226 and other gamma emitters, other than uranium (and its short-lived 

progeny), in developing the recommended exposure rates to submersion? 

7.2 Exposure from Contaminated Surfaces (Section 7.1.2) 

We do not understand the following discussion in Section 7.1.2: “The floor contamination level 

is then estimated as Floor Concentration (dpm/m2

) = Air Concentration (dpm/m3) × 

2.37E4 meters. This method calculates the surface contamination over 1 m2, and the dose factors 

in Table 6.1 should be used.” The reference to Table 6.1 is inappropriate. Table 6.1 provides 

doses for environmental exposure, based on an air concentration of 7 dpm/m3

 for workers in 

areas away from the main operations area. 

In addition, we have concerns regarding the methods used to derive the buildup of contamination 

on surfaces using the deposition velocity approach. This issue is discussed extensively in our 

review of TBD-6000, and is not repeated here. 

Another concern is external exposures to deposited radioactivity in ore handling areas. In ore 

handling areas, it would appear that consideration needs to be given to the radionuclides that 

comprise the entire uranium decay series, not just separated uranium. In addition, surface 

contamination in ore handling areas may have come about from spills. As a result, the 
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deposition velocity approach may underestimate the external doses from surface contamination 

in areas where surface contamination was dominated by spills. 

7.3 Process Specific Dose Rates (Section 7.2) 

Table 7.1 presents external exposure rates (mR/hr and mrem/hr) by major step in the uranium 

refining operation, and by tasks associated with each step. The number of work hours per day 

for each task in each refining step is provided, along with the external dose rate to penetrating 

and non-penetrating radiation. Non-penetrating exposure rates are provided for hands and also 

for other organs. Table 7.2 presents generic external exposure rates as a function of distance 

from different size drums and for drums containing recently separated uranium and drums 

containing pitchblende ore. Based on the information provided in Tables 7.1 and 7.2, Table 7.3 

presents the recommended weekly median dose rate and its GSD for each uranium refinery 

operation, each job title, each external exposure pathway, and each exposure geometry. Table 

7.3 is the most important table, because it is intended to be used by dose reconstructors to derive 

external exposures. 

Table 7.1 appears to have a number of typos, and it is difficult to understand what the various 

values in the table mean and how they were derived. On first inspection, column 2 titled 

“duration (h/d)” would seem to provide the typical number of hours per day a worker employed 

in a given refinery operation was involved in a given task. For example, for “Ore Digestion” 

operations, column 2 seems to indicate that a typical worker involved in this job category spent 

6 hours per day at 45 inches from a drum of high grade pitchblende ore, 2 hours per day at 

6 inches from a drum of high grade pitchblende ore, and 2 hours per day in direct contact with a 

drum of high grade pitchblende ore. This results in total of 10 hours of exposure per day. 

However, for the “Boildown and Denitration” step, there are 4 tasks that add up to 15 hours per 

work day. This does not seem reasonable, unless the worker is multitasking. If so, the TBD 

should provide some explanation in this regard. 

The source for the data in the Ore Digestion section of Table 7.1 is ORAUT 2005 (Table A-33), 

where the units for these particular measurements are mR/hr, not mrem/hr. Presumably, NIOSH 

has assumed that exposures in mR/hr are equivalent to skin doses in mrem/hr, which is 

reasonable. Nevertheless, NIOSH should provide a listing and discussion of the assumptions 

used in developing Table 7.1. 

In the same section of Table 7.1, the “Non-penetrating (other)” dose is listed as 100 mrem/hr. 

However, in Section 3.3.1 (p. 7), the authors state that the non-penetrating dose to the skin other 

than hands and arms is 20.8 mrem/hr, and the exposure duration is 50% of the work day. While 

the dose rate in Table 7.1 is claimant favorable, the differences between the two sections should 

be reconciled. Similarly, Table 7.1 lists the non-penetrating exposure to the hands as 

66 mrem/hr, while Section 3.3.1 quotes a value of 233 mrad/hr. Again, the differences between 

Section 3.3.1 and Table 7.1 should be explained. Why include the information in Section 3.3.1 if 

it is not used? Furthermore, it is not apparent why, in Table 7.1, the contact dose to the hands 

from non-penetrating radiation should be less than the non-penetrating dose to other parts of the 

body. Based on the methodology proposed in Section 3.3.1, the non-penetrating dose to other 

parts of the body can be assumed to be 10 times the photon dose at 1 foot. Applying this model 
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to the source data used in constructing the Ore Digestion section of Table 7.1 would result in a 

dose of about 30 mrem/hr. This value appears to be more consistent with a non-penetrating dose 

to the hands of 66 mrem/hr. 

In Table 7.1 (p. 28) under “Boildown and Denitration” penetrating radiation (mR/hr), the table 

lists the exposure from a 55-gallon drum with 100-day progeny at a distance of 100 cm as 

3.10 mR/hr, citing Table 7.2 as the reference. Similarly, the table lists the exposure at 1 cm as 

0.28 mR/hr. Referring to Table 7.2, one sees that the exposure at 100 cm is 0.3 mR/hr, and 

4.5 mR/hr at 1 cm. A non-penetrating dose based on exposure to a 55-gallon drum at 30 cm is 

quoted as 4.5 mrem/hr. This is actually the exposure (in mR/h) at 1 cm per Table 7.2. We do 

not know whether these are typographical errors or systematic errors that were propagated into 

the Table 7.3 calculations. 

In Table 7.1 (p. 29) under “Fluorination” penetrating radiation (mR/hr), NIOSH quotes a value 

of 0.28, based on exposure to ore. The relevance of using ore as a surrogate for the exposure 

source in fluorination operations is not apparent. C&H 1960 (p. 92/456) notes that workers 

involved in the fluorination of UF4 received doses of 4 to 12 R per month (or up to 70 mR/hr) 

over extended periods, based on personal film badge monitoring. This suggests that exposures of 

this class of workers to penetrating radiation may be understated significantly. 

7.4 Drum Doses (Section 7.3) 

Table 7.2 of the TBD presents external exposure rates (mR/hr) as a function of distance from 

various size drums. The exposure rates appear to be reasonable. 

7.5 Summary of External Doses Received by Workers During Operations (Section 7.4) 

Table 7.3 in the TBD is a large summary table where external doses from five sources are 

presented for work weeks of varying length for various unit operations. No explanation is 

provided as to how the median and GSD values in Table 7.3 are derived. Consider again the Ore 

Digestion operator. According to Table 7.3, this worker receives a daily external exposure from 

contaminated surfaces of 0.206 mR/day based on a 40-hr work week. It should be noted that 

exposures in Table 7.3 are adjusted for annual calendar days, rather than work days. From 

Section 7.1.2, the deposition factor is 2.37E4 m, and from Table 3.10, the conversion factor for 

surface contamination is 4.49E-09 mR/d per dpm/m2

. One also needs the air concentration 

(dpm/m3

) to calculate the daily exposures. Section 7 is silent on what air concentrations to use, 

but we presume that they are the dust concentrations subsequently presented in Section 8 of 

TBD-6001. According to Table 8.3, the median air concentration for the Ore Digestion operator 

(handling pitchblende ore) is 49 dpm/m3

. From this information, one can calculate that daily 

exposure is 5.21E-03 mR/day (2.37E04 m × 49 dpm/m3 × 4.49E-09 mR/day per dpm/m2). Since 

this exposure is based on a working day and, for a 40-hr work week, there are 250 work days per 

365 calendar days, the exposure adjusted to calendar days would be 3.57E-03 mR/calendar-day. 

This is lower than the value of 0.206 reported in Table 7.3 by about a factor of 60. We 

considered the possibility that NIOSH had used 95th percentile values rather than median values 

for the air concentrations. Using a GSD of 4.949 from Table 8.3, one would estimate the 95th
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percentile air concentration to be 678 dpm/m3 (49x 4.9391.645). We do not understand the basis 

for this discrepancy. 

Given that the objective of the TBD is to provide a default method for reconstructing doses that 

are claimant favorable to all workers, the 95th percentile values would seem to be more 

appropriate than the median values of the full distribution. We also recognize that using the 

upper 95th percentile values for the same worker week after week might be overly conservative. 

However, such an approach might not be overly conservative if the nature of a given worker’s 

job placed him or her at a high end location week after week. These issues need to be discussed 

in the TBD, with appropriate guidance provided to the dose reconstructor on how to use the 

information in the TBD. 

Finally, very little information is provided in the TBD as to how the relative exposures to the 

various classes of workers (Job Titles) in Table 7.3 were developed. This is presumably covered 

later in Section 8, but should be cross-referenced here. 

8.0 OCCUPATIONAL INTERNAL DOSE (SECTION 8) 

In the introductory material for Section 8 (page 38), the authors state the following: 

For each process, there is a table of internal dosimetry parameters – particle size 

and solubility information. The tabulated values are for reference only, the ICRP 

(1994) default values are to be used for all internal dose calculations (see 

Section 3.5). 

The meaning here is not clear. Where are the tabulated internal dosimetry parameters that are for 

reference only and not to be used? 

8.1 Process Specific Uranium Air Sampling Data (Section 8.2) 

This section of TBD-6001 reviews the process-specific, airborne uranium exposure summary 

data reported in C&H 1960. The range and average reported by C&H are used to estimate 

lognormal distributions for use in dose reconstruction for the job categories reported in the C&H 

1960 exposure tables. Tables are included for each of seven unit operations involved in uranium 

refining—digestion, denitration, oxide reduction, hydrofluorination, metal reduction, metal 

recasting, and UF6 fluorination. Tables 8.2, 8.6, 8.9, 8.12, 8.15, 8.18, and 8.21 in Section 8.2 of 

TBD-6001 repeat the process-specific airborne uranium exposure summary data for the seven 

operations reported in C&H 1960 Tables 3, 4, 5, 6, 8, 9, and 10, respectively. (The ore sampling 

stage is not included in the TBD-6001 tables, but was included in C&H 1960 Tables 1 and 2.) 

In Tables 8.3, 8.7, 8.10, 8.13, 8.16, 8.19, and 8.22 of Section 8.2 of TBD-6001, the median and 

GSD of 114 lognormal distributions are reported for various tasks within the C&H unit 

operations. The lognormal distributions are estimated from the set of summary statistics reported 

in C&H 1960—the mean and range—using the method reported in Section 2.1.22 of TIB-5000 

(Strom 2007). (The procedures advised in TIB-5000 were not part of this review. It should be 

noted that in several of the TBD-6001 lognormal tables, the reported GSD is less than 1, 
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although the GSD for a lognormal distribution must be greater than 1. Hence, there appears to 

be an error here that needs to be corrected.) 

Breathing zone (BZ), General Area (GA), and time-weighted daily average (DWA) exposures 

are included in all these sets of tables. Although lognormal distributions are fitted to all three 

types of measurements in TBD-6001, only the DWA measurements are used to develop the 

uranium dust intake rates reported in Section 8.5 of TBD-6001. 

The C&H data are the underlying source of information for the lognormal distributions and 

exposure estimates presented in TBD-6001. The data presented in TBD-6001 faithfully 

reproduce the values in the original C&H tables. However, only anecdotal information is 

provided in the 1960 C&H journal article on the details of data processing, and no references are 

provided for the sources of the original data. Details of the sampling plan for selecting plants 

and workers for monitoring, the sample sizes at various facilities, the details of the weighting 

procedures, or the representativeness of the data as a whole are not provided. These 

shortcomings are inadequately addressed in TBD-6001. One goal of this review of Section 8.2 is 

to validate the C&H data to the degree possible. A second goal is to review the use of these data 

in TBD-6001 in estimating the lognormal distributions that are the basis for reconstruction of 

inhalation intakes. 

Validation of C&H 1960 Exposure Data 

The most complete set of occupational exposures available for validating the C&H study are the 

MCW airborne exposure data reported in ORAUT 2005. Tables 12 and 13 of ORAUT 2005 

contain detailed data that were available for the C&H study, which also included information 

from other sites. Tables 12 (Plant 4) and 13 (Plant 6) from ORAUT 2005 are included in this 

review as Appendix A for inspection. 

At first glance, the fact that Figure 16 in the C&H report covers exactly the same span of years as 

the data contained in Tables 12 and 13 of ORAUT 2005 supports the hypothesis that the MCW 

data are a very important component of the data available to the C&H study. Figure A-1 

contains a scatter plot of the MCW Plant 6 exposures contained in Table 13 of ORAUT 2005, 

and provides a comparison of the 95th percentile from Table 13 to the yearly 95th percentile 

estimates reported in Table 8.27 of TBD-6001. The close agreement in the 95th percentiles and 

the fact that the TBD-6001 95th percentile exceeds the MCW 95th percentile support the premise 

that the C&H data set contained the MCW data plus additional observations from other facilities. 

In order to assess the representativeness of the C&H 1960 data and the TDB-6001 exposure 

estimates, SC&A analyzed the combined MCW data for Plants 4 and 6. Our goal was to validate 

the summary statistics for the job categories reported in C&H 1960 (and repeated in TBD-6001) 

and the lognormal distributions reported in TDB-6001 using only the MCW data. Due to the 

large number of lognormal distributions presented in the seven tables in Section 8.2 of 

TBD-6001, only the distributions for the DWA exposures were validated in this review. We 

selected one C&H job sub-category, generally the earliest in time, within each job (i.e., unit 

operations) category, and only the MCW data for the appropriate years were included in the 

comparison. 
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Table 3 contains the results of our analysis. The range and average reported in each C&H table 

are shown with the corresponding MCW Plants 4 and 6 statistics. The Plants 4 and 6 values are 

also expressed as a percentage of the corresponding C&H table entry, with 100% indicating 

equality of the two values. The results for the lower end of the range (minimums) are plotted in 

Figure 2 and results for the upper end of the range (maximums) are plotted in Figure 3. In 

Figure 2, the minimums at Plants 4 and 6 are smaller than those reported in C&H 1960. 

Examination of Table 3 shows that in all but one case, the minimum of the MCW data for 

Plants 4 and 6 is smaller (<100%). Although the two data sets appear to have a close 

correspondence when the upper end of exposures are viewed on this log scale, examination of 

Table 3 shows that in all cases, the MCW data for Plants 4 and 6 exhibit larger maximums 

(>100%). In two cases, ore sampling and ore digestion, the Plants 4 and 6 exposures exceed the 

C&H upper end of range by factors of 4 to 7. This is an unexpected result, since the larger C&H 

data set would be expected to have a lower minimum exposure than the included MCW data set. 

The larger maximums and smaller minimums from the Plants 4 and 6 data indicate that the 

ranges reported by C&H are narrower than the MCW Plants 4 and 6 exposures would suggest. 

However, as seen in Figure 4 and Table 3, the average exposures reported in C&H and the 

Plants 4 and 6 data show no clear pattern of differences. The Plants 4 and 6 data are significantly 

higher for one operation (ore digestion), and about the same as C&H in the others. 

The mean and standard deviation of the logarithms of the MCW exposure data were also 

calculated for the selected job subcategories in C&H Tables 3, 4, 5, 6, 8, and 9. The data in the 

last six tables were used to estimate the lognormal distributions found in TBD-6001 Tables 8.3, 

8.7, 8.10, 8.13, 8.16, and 8.19, respectively. Note that the ore sampling stage (C&H Tables 1 

and 2) is not addressed in the Section 8.2 tables in TBD-6001. The lognormal distribution was 

used to estimate the median, GSD, and 95th percentiles for each category. The TBD-6001 

lognormal median, GSD, and 95th percentiles are compared with the corresponding statistics 

derived from the Plants 4 and 6 data in Table 4. The medians are compared in a bar chart in 

Figure 5. The medians show no clear pattern of differences. However, for denitration, oxide 

reduction, and hydrofluorination, the TBD-6001 medians are higher than the Plants 4 and 6 

medians by factors of 3 to 9. This unusual discrepancy may be connected to other anomalies 

discussed below. 

The GSDs of the Plants 4 and 6 data are compared with the GSDs reported in the TBD-6001 

tables in Figure 6. Note that the lognormal distributions presented in TDB-6001 have GSDs that 

often are significantly lower than those for the MCW exposures. In particular, the TBD-6001 

estimates of the GSD for denitration and oxide reduction in Plants 4 and 6 are more than a factor 

of 6 higher than the TBD-6001 estimates. These large differences occur in two of the three 

categories with high estimates for the median. This discrepancy may indicate a systemic 

problem in the application of methods prescribed in Section 2.1.22 of Strom 2007 for estimating 

lognormal distributions from the minimum, average, and maximum. These job categories also 

have high values in C&H 1960 for the lower end of the range, when compared to the MCW data. 

This may be another possible explanation for the large differences in the GSD estimates. In this 

case, overestimation of the lower end of the range of exposures is not necessarily claimant 

favorable, because this may lead to underestimation of the GSD. 
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The estimated 95th percentiles of exposure are compared in the chart in Figure 7. Four of the 

lognormal distributions derived from the MCW exposures have 95th percentiles that are higher 

than those presented in TDB-6001. As shown in Table 4, the 95th percentiles for digestion, 

denitration, oxide reduction, and recasting at MCW are higher than those in TDB-6001 by 

factors of 2 to 5. Anomalies of this magnitude raise questions concerning the weighting 

procedures in general, and the relative weight assigned to the MCW data in the C&H study. 

Use of C&H 1948 to 1956 Averages 

Although TBD-6001 addresses exposures over the entire period from 1942 to 1958, the C&H 

data cover only the period from 1948 to 1956. Hence, the mean exposures reported by C&H are 

averages over the years 1948 to 1956 only. To address exposures to workers in the pre-1948 

time period, TBD-6001 assumes that the 1948 exposures are applicable to the earlier years. 

However, the average exposures reported by C&H do not give any weight to exposures in the 

years before 1948, and exposures in 1948 are among the highest exposures reported by C&H. A 

more appropriate time-weighted mean exposure would account for each year from 1942 to 1958. 

To see the effect of the missing years, new averages were calculated here by extrapolating the 

1948–1956 data to the years 1942–1947 and 1957–1958. Claimant-favorable estimates of 

exposures in the years 1942–1947 were constructed for each job category by assigning either the 

upper end of the C&H range or the 95th percentile of the estimated lognormal distributions in 

TDB-6001 to each year before 1948. For the years 1957 and 1958, the average exposure was 

used. 

Table 5 shows a comparison of the average exposures over the entire 1942–1958 period with the 

C&H average exposure when the 95th percentile is used as a claimant-favorable estimate of 

exposures in the years before 1948. The ratio of the 1942–1958 average to the C&H 1948–1956 

average is also shown in the table. A graph of the ratios is shown in Figure 8. As expected, the 

ratios for the 10 job categories, which only apply to years after 1949, are equal to 1, since these 

categories are not affected by assumptions regarding the early years. However, the job 

categories that existed in 1948 have ratios as high as a factor of 3.5, indicating that the 1948–

1956 averages reported in C&H are not claimant favorable if used for the entire 1942–1958 time 

period without adjustment to account for exposures in the earlier years. Over all categories, the 

1942–1958 average exceeds the C&H 1948–1956 average by a factor of 1.63. 

Table 6 shows a similar comparison of the average exposures over the two time periods when the 

upper end of the C&H range is used as a claimant-favorable estimate for exposures in the years 

before 1948. The categories that were most affected by giving weight to the early years using 

the 95th percentile show smaller ratios, in general, when the upper end of the range is used, 

because the 95th percentiles of the TBD-6001 lognormals often exceed the upper end of the C&H 

range. When using the upper end of the C&H exposures, the ratios range up to a factor of 

approximately 2.5. Over all categories, the 1942–1958 average exceeds the C&H 1948–1956 

average by a factor of 1.68. A graph of the ratios in Table 6 is shown in Figure 9. 

Clearly, use of the average uranium dust exposure data from C&H 1960 is not claimant favorable 

to those workers whose exposures began prior to 1948. 
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Table 3. Comparison of MCW Plants 4 and 6 Average Exposure and Range Values with those Rep

C&H Lower End of Range Average Upper 

Table 

No. Unit Operation Sub-category C&H Plants 4 & 6 % of C&H C&H Plants 4 & 6 % of C&H C&H P

(dpm/m3) (dpm/m3) (dpm/m3) (dpm/m3) (dpm/m3) 

1 Ore Sampling Manual 140 3 2.1% 800 762 177% 3,000 3 Digestion Ore 7 6 86% 110 249 443% 350 4 Denitration Up to 1949 4,200 46 1.1% 15,000 8,230 64% 32,000 5 Oxide Reduction Tray Furnace 9,800 686 7.0% 20,000 12,168 44% 32,000 6 Hydrofluorination UO2 Loaders 260 35 13% 3,300 2,031 97% 8,900 

8 Reduction to Metal Bomb Preparation 300 35 12% 875 694 122% 2,300 9 Metal Recasting Recasting Furnace 110 189 172% 1,100 2,414 216% 4,100 

Table 4. Comparison of Lognormal Distribution Parameters for MCW Plants 4 and 6 with TBD-

Parameters 

 Median GSD 

TBD-6001 TBD-6001 Plants 4 & 6 % of TDB-6001 TBD-6001 Plants 4 & 6 % of TDB-6001 TBD-6001 

Table No. Unit Operation Sub-category (dpm/m3) (dpm/m3) (dpm/m3) 

-- Ore Sampling Manual -- 101 -- -- 6.6 -- -- 

8.3 Digestion Ore 49.0 109 223% 4.9 3.9 80% 678 8.7 Denitration Up to 1949 11,593 1,264 11% 1.7 10.9 651% 27,055 

8.10 Oxide Reduction Tray Furnace 17,709 6,125 35% 1.3 8.6 675% 26,443 8.13 Hydrofluorination UO2 Loaders 1,334 500 37% 6.1 5.0 81% 26,243 

8.16 Reduction to Metal Bomb Preparation 240 301 125% 5.0 3.4 68% 3,388 

8.19 Metal Recasting Recasting Furnace 672 1,145 170% 2.7 7.8 292% 3,407 
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Table 5. Comparison of Estimated Average Exposure from 1942 to 1958 with C&H 

1948 to 1956 Average Exposure 

(Assumes 95th Percentile Estimate for Years 1942 to 1947) 

 Ratio of 

 C&H Averages 

 Average Average 1942–1958/ 

Job Category 1942–1958 1948–1956 1948–1956 

 (dpm/m3

) (dpm/m3) 

Ore Sampling-Manual 1,576 800 1.97

Ore Sampling-Automatic 158 140 1.13

Sampling-Concentrate 158 140 1.13

Digestion-Ore 310 110 2.82

Digestion-Concentrate 61 40 1.53

Denitration-Up to 1949 24,041 15,000 1.60

Denitration-After 1949 130 130 1.00

Oxide Reduction-Tray Furnace 25,522 20,000 1.28

Oxide Reduction-Multiple Hearth 700 700 1.00

Oxide Reduction-Horizontal Reactor 140 140 1.00

Hydrofluorination-UO2 Loaders 11,398 3,300 3.45

Hydrofluorination-Furnace Operator 1,228 500 2.46

Hydrofluorination-UF4 Packagers 2,762 1,300 2.12

Reduction to Metal-Bomb Preparation up to 1951 2,383 875 2.72

Reduction to Metal-Reduction Operations up to 1951 814 300 2.71

Reduction to Metal-Bomb Preparation after 1951 30 30 1.00

Reduction to Metal-Reduction Operations after 1951 11 11 1.00

Metal Recasting-Crucible Loading up to 1951 64 51 1.25

Metal Recasting-Recasting Furnace up to 1951 2,484 1,100 2.26

Metal Recasting-Crucible Burnout up to 1951 139 50 2.77

Metal Recasting-Billet Cleaning up to 1951 79 47 1.69

Metal Recasting-Crucible Assembly up to 1951 732 360 2.03

Metal Recasting-Crucible Loading after 1951 36 36 1.00

Metal Recasting-Recasting Furnace after 1951 47 47 1.00

Metal Recasting-Crucible Burnout after 1951 70 70 1.00

Metal Recasting-Billet Cleaning after 1951 28 28 1.00

Metal Recasting-Crucible Assembly after 1951 55 55 1.00

UF6 Fluorination-Hex Loaders 3,012 2,600 1.16

UF6 Fluorination-Fluorination Operators 2,130 1,100 1.94

UF6 Fluorination-Still Operators 511 350 1.46

UF6 Fluorination-Central Loaders 635 550 1.16

 

All Categories 2,627 1,612 1.63
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Table 6. Comparison of Estimated Average Exposure from 1942 to 1958 with 

C&H 1948 to 1956 Average Exposure 

(Assumes Upper End of Range Estimate for Years 1942 to 1947) 

 Ratio of 

 C&H Averages 

 Average Average 1942–1958/ 

Job Category 1942–1958 1948–1956 1948–1956 

 (dpm/m3

) (dpm/m3) 

Ore Sampling-Manual 1,576 800 1.97

Ore Sampling-Automatic 158 140 1.13

Sampling-Concentrate 158 140 1.13

Digestion-Ore 195 110 1.77

Digestion-Concentrate 61 40 1.53

Denitration-Up to 1949 27,750 15,000 1.85

Denitration-After 1949 130 130 1.00

Oxide Reduction-Tray Furnace 30,286 20,000 1.51

Oxide Reduction-Multiple Hearth 700 700 1.00

Oxide Reduction-Horizontal Reactor 140 140 1.00

Hydrofluorination-UO2 Loaders 5,276 3,300 1.60

Hydrofluorination-Furnace Operator 747 500 1.49

Hydrofluorination-UF4 Packagers 2,394 1,300 1.84

Reduction to Metal-Bomb Preparation up to 1951 1,730 875 1.98

Reduction to Metal-Reduction Operations up to 1951 702 300 2.34

Reduction to Metal-Bomb Preparation after 1951 30 30 1.00

Reduction to Metal-Reduction Operations after 1951 11 11 1.00

Metal Recasting-Crucible Loading up to 1951 67 51 1.31

Metal Recasting-Recasting Furnace up to 1951 2,900 1,100 2.64

Metal Recasting-Crucible Burnout up to 1951 80 50 1.60

Metal Recasting-Billet Cleaning up to 1951 67 47 1.42

Metal Recasting-Crucible Assembly up to 1951 468 360 1.30

Metal Recasting-Crucible Loading after 1951 36 36 1.00

Metal Recasting-Recasting Furnace after 1951 47 47 1.00

Metal Recasting-Crucible Burnout after 1951 70 70 1.00

Metal Recasting-Billet Cleaning after 1951 28 28 1.00

Metal Recasting-Crucible Assembly after 1951 55 55 1.00

UF6 Fluorination-Hex Loaders 4,259 2,600 1.64

UF6 Fluorination-Fluorination Operators 2,688 1,100 2.44

UF6 Fluorination-Still Operators 548 350 1.56

UF6 Fluorination-Central Loaders 744 550 1.35

 

All Categories 2,713 1,612 1.68
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Lower End of Range

1

10

100

1,000

10,000

Ore Sampling

Digestion

Denitration

Oxide Reduction

Hydrofluorination

Reduction to Metal

Metal Recasting

Concentration (dpm/m3)

C&H Plants 4 & 6

Figure 2. Comparison of C&H Tabulated Lower End of Range with 

Mallinckrodt Plants 4 and 6 Lower End of Range 

Upper End of Range

10

100

1,000

10,000

100,000

Ore Sampling

Digestion

Denitration

Oxide Reduction

Hydrofluorination

Reduction to Metal

Metal Recasting

Concentration (dpm/m3)

C&H Plants 4 & 6

Figure 3. Comparison of C&H Tabulated Upper End of Range with 

Mallinckrodt Plants 4 and 6 Upper End of Range 
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Average Exposure

10

100

1,000

10,000

100,000

Ore Sampling

Digestion

Denitration

Oxide Reduction

Hydrofluorination

Reduction to Metal

Metal Recasting

Concentration (dpm/m3)

C&H Plants 4 & 6

Figure 4. Comparison of C&H Tabulated Average Exposure with 

Mallinckrodt Plants 4 and 6 Average Exposure 

Lognormal Median

10

100

1,000

10,000

100,000

Digestion

Denitration

Oxide Reduction

Hydrofluorination

Reduction to Metal

Metal Recasting

Concentration (dpm/m3)

TBD-6001 Plants 4 & 6

Figure 5. Comparison of TBD-6001 Lognormal Median with Mallinckrodt Plants 4 

and 6 Lognormal Median 
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Geometric Standard Deviation (GSD)

0

2

4

6

8

10

12

14

Digestion

Denitration

Oxide Reduction

Hydrofluorination

Reduction to Metal

Metal Recasting

GSD Value

TBD-6001 Plants 4 & 6

Figure 6. Comparison of TBD-6001 Lognormal GSD with 

Mallinckrodt Plants 4 and 6 Lognormal GSD 

95th Percentile of Lognormal

10

100

1,000

10,000

100,000

Digestion

Denitration

Oxide Reduction

Hydrofluorination

Reduction to Metal

Metal Recasting

Concentration (dpm/m3)

TBD-6001 Plants 4 & 6

Figure 7. Comparison of TBD-6001 Lognormal 95th Percentile with 

Mallinckrodt Plants 4 and 6 Lognormal 95th Percentile 
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Average Concentration(1942-1958) / C&H Average Concentration(1948-1956)

2.0

1.1

1.1

2.8

1.5

1.6

1.0

1.3

1.0

1.0

3.5

2.5

2.1

2.7

2.7

1.0

1.0

1.2

2.3

2.8

1.7

2.0

1.0

1.0

1.0

1.0

1.0

1.2

1.9

1.5

1.2

1.6

0.5 1.0 1.5 2.0 2.5 3.0 3.5

Ore Sampling-Manual

Ore Sampling-Automatic

Sampling-Concentrate

Digestion-Ore

Digestion-Concentrate

Denitration-Up to 1949

Denitration-After 1949

Oxide Reduction-Tray Furnace

Oxide Reduction-Multiple Hearth

Oxide Reduction-Horizontal Reactor

Hydrofluorination-UO2 Loaders

Hydrofluorination-Furnace Operator Hydrofluorination-UF4 Packagers

Reduction to Metal-Bomb Preparation up to 1951

Reduction to Metal-Reduction Operations up to 1951 Reduction to Metal-Bomb Preparation after 1951

Reduction to Metal-Reduction Operations after 1951

Metal Recasting-Crucible Loading up to 1951

Metal Recasting-Recasting Furnace up to 1951

Metal Recasting-Crucible Burnout up to 1951

Metal Recasting-Billet Cleaning up to 1951 Metal Recasting-Crucible Assembly up to 1951

Metal Recasting-Crucible Loading after 1951

Metal Recasting-Recasting Furnace after 1951

Metal Recasting-Crucible Burnout after 1951

Metal Recasting-Billet Cleaning after 1951

Metal Recasting-Crucible Assembly after 1951

UF6 Fluorination-Hex Loaders

UF6 Fluorination-Fluorination Operators

UF6 Fluorination-Still Operators

UF6 Fluorination-Central Loaders

All Categories

Figure 8. Comparison of Estimated Average Exposure (dpm/m3) from 1942 to 1958 

with C&H 1948 to 1956 Average Exposure (dpm/m3

) 

(Assumes 95th Percentile Estimate for Years 1942 to 1947) 

Average Concentration(1942-1958) / C&H Average Concentration(1948-1956)

2.0

1.1

1.1

1.8

1.5

1.9

1.0

1.5

1.0

1.0

1.6

1.5

1.8

2.0

2.3

1.0

1.0

1.3

2.6

1.6

1.4

1.3

1.0

1.0

1.0

1.0

1.0

1.6

2.4

1.6

1.4

1.7

0.5 1.0 1.5 2.0 2.5 3.0 3.5

Ore Sampling-Manual

Ore Sampling-Automatic

Sampling-Concentrate

Digestion-Ore

Digestion-Concentrate

Denitration-Up to 1949

Denitration-After 1949

Oxide Reduction-Tray Furnace

Oxide Reduction-Multiple Hearth

Oxide Reduction-Horizontal Reactor

Hydrofluorination-UO2 Loaders

Hydrofluorination-Furnace Operator Hydrofluorination-UF4 Packagers

Reduction to Metal-Bomb Preparation up to 1951

Reduction to Metal-Reduction Operations up to 1951 Reduction to Metal-Bomb Preparation after 1951

Reduction to Metal-Reduction Operations after 1951

Metal Recasting-Crucible Loading up to 1951

Metal Recasting-Recasting Furnace up to 1951

Metal Recasting-Crucible Burnout up to 1951

Metal Recasting-Billet Cleaning up to 1951 Metal Recasting-Crucible Assembly up to 1951

Metal Recasting-Crucible Loading after 1951

Metal Recasting-Recasting Furnace after 1951

Metal Recasting-Crucible Burnout after 1951

Metal Recasting-Billet Cleaning after 1951

Metal Recasting-Crucible Assembly after 1951

UF6 Fluorination-Hex Loaders

UF6 Fluorination-Fluorination Operators

UF6 Fluorination-Still Operators

UF6 Fluorination-Central Loaders

All Categories

Figure 9. Comparison of Estimated Average Exposure (dpm/m3) from 1942 to 1958 

with C&H 1948 to 1956 Average Exposure (dpm/m3) 

(Assumes Upper End of Range Estimate for Years 1942 to 1947) 
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8.2 Resuspension during Periods with No Uranium Operations (Section 8.3) 

Resuspension of radioactive dust during periods of non-operation is discussed in Section 8.3 

(p. 48). This same material is duplicated under the same title in Section 8.5.2 (p. 58). The 

methodology presented relies on a prior analysis of uranium metal-working operations. The 

methodology assumes that particles with a 5-μm AMAD in a dust cloud containing 

7,000 dpm/m3

 settle at a terminal velocity of 7.5E-04 m/s. Settling occurs during 20 hours of 

daily operation for a 1-year period. The calculated surface contamination is 3.44E07 pCi/m2

. 

(About 202 work days per year are implicit in this contamination level, i.e., 7,000dpm/m3 × 

7.5E-04 m/s × 1/2.22 pCi/dpm × 3.6E03 sec/hr × 20 hr/day × 202 day/yr = 3.44E07 pCi/m2). 

However, in Section 3.4.2, exposures from contaminated surfaces are based on continuous 

deposition for 365 days. We do not understand why calculations in Section 8.4.2 are not done on 

the same basis as those in 3.4.2. 

We have already described elsewhere in this review (see Section 6.1.1) and in SC&A 2007 our 

concerns with using terminal velocity for 5-μm AMAD particles to estimate surface 

contamination levels. TBD-6001 (Section 8.3) assumes a resuspension factor 1 × 10-6/m. SC&A 

had previously questioned the use of this parameter value in SC&A 2007, indicating that a higher 

value would be consistent with available information. In addition, review of the average 

exposure data in C&H 1960 suggests that the use of 7,000 dpm/m3 as the air concentration 

estimate may be low for certain unit operations. Average values of daily weighted exposures for 

denitration operations up to 1949 were 15,000 dpm/m3 (C&H 1960, Table 4), and 

20,000 dpm/m3 for oxide reduction in trays (C&H 1960, Table 5). These are average values for 

all surveys for those operations over the relevant time periods. On the other hand, an air 

concentration of 7,000 dpm/m3 is probably claimant favorable for the other unit operations 

considered in TBD-6001. 

8.3 Time-Dependent Air Concentration Data (Section 8.4) 

NIOSH states that the relevant evaluation period for TBD-6001 is 1942 through 1958; however, 

the C&H 1960 report covers only the period 1948 through 1956. To address this difference in 

time periods, it is assumed in Table 8.28 (p. 53) that the year-specific correction factor of 6.89 be 

used for the years prior to 1948, and the year-specific correction factor of 0.0792 be used after 

1956. Use of the 6.89 factor does not appear to be claimant favorable for the period 1942 

through 1947. As shown in Figure 16 of C&H 1960, reproduced as Figure 1 in TBD-6001, there 

was a rapid decline (greater than an order of magnitude) in the weighted dust exposures over the 

period 1948–1950, as process improvements were implemented. This suggests that dust levels 

prior to 1948 could be substantially higher than implied by the year-specific correction factor. 

For example, NIOSH estimates a mean air concentration of 7,398 dpm/m3

 for 1948 (see 

Table 8.27). Values of daily weighted average exposures reported at MCW for the period 1946–

1948 include the following: 

• TA unloader (operator) – 13,000 dpm/m3 (ORAUT 2005, Table 19) 

• Furnace operator – 24,780 dpm/m3

 (ORAUT 2005, Table 20) 

• LF-9/brown/UO2/packager/unloader – 38,990 dpm/m3

 (ORAUT 2005, Table 20) 

• Miller (UO3QM-2) – 12,600 dpm/m3

 (ORAUT 2005, Table 20) 
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• Ore room operator – 13,720 dpm/m3

 (ORAUT 2005, Table 20) 

These values are significantly higher than the mean value of 7,398 dpm/m3 calculated by NIOSH 

for 1948. 

Given the fact that correction factors proposed by NIOSH for the period prior to 1948 may lead 

to understated inhalation exposures, SC&A developed an alternative methodology to calculate 

year-specific correction factors. This alternative methodology is presented below. 

Alternative Methodology to Calculate Year-Specific Correction Factors 

The mean exposure concentrations in each year from 1948 to 1956 (derived by digitizing 

Figure 16 in C&H 1960) are presented in Table 8.27 of TBD-6001. Figure 2 of TBD-6001 

shows a plot of the mean concentrations using a logarithmic scale. A similar plot is shown here 

in Figure 10, where the mean concentrations are plotted by year from 1948 to 1956. Due to the 

wide range of mean values, the natural logarithms of the mean concentrations are plotted on the 

vertical axis. The horizontal dashed lines extending from each end of the plot represent the 

NIOSH extrapolation of the 1948 and 1956 values to the earlier and later time periods, 

respectively. The least squares trend line which best fits the data is also shown in the figure. 

The trend line has a relatively high R2

 of 0.78 and a significantly negative trend coefficient of 

-.51. (The t-statistic for the slope of the trend line is -5.02. A t-statistic that is lower than -2.3 

indicates that the trend coefficient is significantly negative.). Given the relatively good fit of the 

trend line, it is not unreasonable to use the trend line for estimating the dose to workers exposed 

during time periods before 1948 and after 1956. 

Table 8.28 of TBD-6001 presents a table of ratios (correction factors) prescribed for adjusting 

claimant exposures to airborne uranium in individual years 1942–1958. The ratios are derived 

from the 1948 to 1956 mean concentrations shown in Figure 10. The tabulated correction factor 

for 1948 is prescribed by NIOSH for use in the years from 1942 to 1947, and the tabulated 

correction factor for 1956 is prescribed for use in the years 1957 and 1958. Figure 11 shows a 

comparison of the TBD-6001 Table 8.28 correction factors with factors derived from the trend 

line in Figure 10. Both sets of ratios are scaled, so that a worker who is employed during the 

entire period from 1948 to 1956 would have an unchanged total dose using these ratios (i.e., the 

average correction factor over these years is equal to 1). For those workers who did not work for 

the entire period or those who worked in the years before 1948 and after 1956, these ratios are 

used to adjust their dose estimates in the years they worked. As shown in Figure 11, the 

TDB-6001 correction factors based on backward extrapolation of the 1948 value are not as 

claimant favorable as the factors derived from trend line extrapolation to the earlier years. 

The TDB-6001 mean concentrations and the trend line estimates of the mean concentration 

plotted in Figure 10 are detailed in Table 7. The exposure correction factors derived from each 

set of mean concentrations are also shown in the table. The correction factors derived from the 

trend line exceed the factors derived in TBD-6001 by the horizontal extrapolation method by as 

much as a factor of 10 in the earlier years. The correction factors derived from the trend line also 

appear to be more claimant favorable in the years with data (1948–1956). The sole exception is 

1948, when the trend line falls appreciably below the data. This is an important exception, 
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because the highest recorded doses (from C&H 1960) occur in this year. For this year, the databased correction factor in TBD-6001 should be retained in order to remain claimant favorable. 

In the period from 1957 to 1958, the trend line leads to less claimant favorable correction factors 

than horizontal extrapolation. The TBD-6001, Table 8.28 factors also should be retained in these 

years to be claimant favorable. 

 Natural Logarithm of Mean Concentration fromTable 8-27

 with Linear Trend Line (dpm/m3)

y = -0.5111x + 1003.2

R2

 = 0.7827

2

3

4

5

6

7

8

9

10

11

1942 1943 1944 1945 1946 1947 1948 1949 1950 1951 1952 1953 1954 1955 1956 1957 1958

x= Year

y=Ln[ Mean Concentration ]

Table 8.27 Mean Concentration Table 8.27 Extrapolated 1948 to 1956 Trend Line

Figure 10. TBD-6001 Table 8.27 Mean Air Concentrations from 1948 to 1956, with 

Extrapolation to Earlier and Later Years and Regression Trend Line (n=9, R2

=0.78) 
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Comparison of Ratios for Extrapolating Exposures in 1948 to 1956 to 

Earlier and Later Years 

0.01

0.1

1

10

100

1942 1943 1944 1945 1946 1947 1948 1949 1950 1951 1952 1953 1954 1955 1956 1957 1958

Year

Ratio to 1948-56 Mean

Table 8.28 Ratios Trend Line Ratios

Figure 11. Comparison of TBD-6001 Table 8.28 Year-Specific Correction Factors with 

Factors Derived from 1948 to 1956 Trend Line 
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Table 7. Comparison of Year-Specific Correction Factors from TBD-6001 Table 8.28 

with Correction Factors Derived from 1948 to 1956 Trend Line 

 Mean Concentration Correction Factor 

 (dpm/m3

) Ratio to 1948–1956 Average 

 TBD-6001 Trend TBD-6001 Trend Percent 

Year (Table 8.27) Line (Table 8.28) Line Difference 

1942 43,388 6.89 78.10 1034% 

1943 26,026 6.89 46.85 580% 

1944 15,611 6.89 28.10 308% 

1945 9,364 6.89 16.86 145% 

1946 5,617 6.89 10.11 47% 

1947 3,369 6.89 6.07 -12% 

1948 7,398 2,021 6.89 3.64 -47% 

1949 964 1,212 0.897 2.18 143% 

1950 349 727 0.325 1.31 303% 

1951 521 436 0.485 0.785 62% 

1952 124 262 0.1154 0.471 308% 

1953 71 157 0.0661 0.283 327% 

1954 94 94.1 0.0875 0.169 94% 

1955 63 56.5 0.0586 0.102 73% 

1956 85 33.9 0.0791 0.061 -23% 

1957 20.3 0.0791 0.037 -54% 

1958 12.2 0.0791 0.022 -72% 

 

Mean (1948–1956) 1,074 556 1.00 1.00 0% 

8.4 Summary (Section 8.5) 

In TBD-6000, NIOSH provided the following guidance with regard to uranium air-sampling 

data: 

For the air sampling data presented in this section, data are presented for 

individual worker positions, as listed in the Harris and Kingsley (1959) tables. 

When a claimant’s job category is known, the air sampling data for the 

corresponding job category can be used for the dose reconstruction. Where the 

claimant’s job category is unknown or does not correspond to a listed category, 

the maximum air sampling data should be used (Battelle 2006, pp. 43–44). 

In its review of TBD-6000, SC&A commended NIOSH on providing this guidance (SC&A 

2007). We did not find similar guidance in TBD-6001 and believe it should be provided there as 

well. We believe that this is particularly important since, as early as 1949, health physicists 

judged that it would be impossible to estimate dust exposures based on job descriptions, because 

the men were transferred from one department to another and no records were made of the 

transfers (NYOO 1949, p. 53). 

Table 8.29 (p. 54) provides intake rates for uranium dust from various operations. It may be 

noted in the table that an ore digestion operator working a 40-hr week would have a median 
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inhalation exposure of 145 pCi/day. We presume that this value is calculated per Section 8.5.1as 

follows: 

I IMBA = 3.288×10−3 Ah, 

where 

IIMBA is the IMBA chronic intake in pCi/d, 

A is the air concentration (pCi/m3

) and 

h is the number of working hours in a year. 

If the measured air concentration has units of dpm/m3

, then divide the constant by 

2.22 (dpm/pCi). 

For a 40-hr work week, h is 2,000 hours and A from Table 8.3 is 49 dpm/m3. (IIMBA = 3.288 × 

10-3 × 2,000 × 49/2.22 = 145 pCi/d.) This is the median average daily exposure for an operator 

handling pitchblende ore. Choice of an operator handling ore rather than concentrates is 

claimant favorable, since the comparable number for handling concentrates is 41 dpm/m3. The 

median average exposure in Table 8.3 is derived from data in Table 8.2, which were taken 

directly from Table 3 of C&H (1960). C&H 1960 refers to the summary values in Table 3 as 

“average daily exposure.” In other tables in C&H 1960, terms such as “DWA” (Tables 5 and 

10), “average weighted exposure” (Table 4), “daily average exposure” (Table 2), “weighted 

average exposure” (Tables 6 and 8), “weighted average” (Table 9), “average exposure” 

(Table 11), and “daily weighted average” (Table 1) are used. We presume these terms are 

synonymous (and, apparently, they are assumed to be synonymous in TBD-6001), but we are not 

sure. NIOSH should clarify this. 
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9.0 MINOR COMMENTS AND TYPOGRAPHICAL ERRORS 

Page viii. In ICRP documents, AMAD is defined as “activity median aerodynamic diameter.” 

See also pages 11 and 27. 

Page 3, line 2. Why is Th refining mentioned when it is not discussed in the TBD? 

Page 3, Section 3.1, third paragraph. Typo: pitchblende (sp.). 

Page 4, third paragraph. The document indicates that uranium recycling occurred “after 1953.” 

According to DOE 2003, Hanford supplied recycled U to ORGDP in 1952. 

Page 6, Section 3.3, first bullet. Typo: “photons” duplicated. 

Page 7, third paragraph. Is there a basis for assuming that the workers’ hands are in contact with 

uranium 50% of the day? The assumption is probably claimant favorable, but if there is support 

for the assumption, it should be provided. 

Page 8, Section 3.3.2. The meaning and intent of the sentence “A quick check....” is not 

obvious. 

Page 8, Section 3.3.3. This section references ORAUT-OTIB-0004 Revision 3 as the source of 

the statement that natural uranium photon energies range from 30 to 250 keV. ORAUT-OTIB0004 iterates the same range, but provides no indication as to the source of the values. 

Page 8, Table 3.5. Typo: We believe that the reference should read “DOE-STD-1136-2004.” 

Page 9. Table 3.7. “and doses” should be eliminated from the table title. It only presents dose 

rates. 

 

Page 10, Section 3.4, last line. Typo: We believe that this should be Sections 3.4 not 3.3. 

Page 10, Section 3.4.1. This section deals only with Exposure from Submersion. Exposure from 

Contaminated Surfaces is discussed in Section 3.4.2. The authors should discuss why different 

photon energy distributions are used in Sections 3.4.1 and 3.4.2. 

Page 11, Table 3.9. The source of the data for this table is not apparent. 

Page 12, Section 3.4.3. The source of the data in Table 3.11 is not apparent. 

Page 15, Section 4.1, first sentence. “Hot” uranium ore should be defined, as should the phrase 

“concentrate (without processing).” Concentrate generally implies a product resulting from a 

processing operation. Presumably “hot’ ore is high-grade pitchblende containing 20% to 50% 

U3O8. 
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Page 18. Section 4.10. What is “purified uranium ore?” This is not common terminology. The 

referenced figure seems irrelevant; it shows a rail car modified to handle shipment of hot ore. 

Typo: Ore is singular. 

Page 18, Section 4.10. The authors state that, “The dose rates due to neutrons from spontaneous 

fission are about 0.09% of the photon dose rates.” What is the source of this information? 

Page 18, first line. Typo: Eisenbud (sp.). 

Page 23, Table 6.1. External exposures from submersion are presented here in units of 

mrem/day, while comparable exposures in Table 7.3 are presented in units of mR/day. It would 

facilitate comparison of environmental and occupational doses if the units were consistent. 

Page 26, Section 7.1.2. The table citation should be Table 3.10, not Table 3.9. 

Page 29, Table 7.1. Table entries for hydrofluorination list Tables 1.3 and 5.6 as references. 

There are no such tables in TBD-6001. 

Page 31, Section 7.4. The text notes that “skin” pathways are at a skin depth of 0.07 mg/cm2, 

while page 7, second paragraph, states that skin doses are based on 7 mg/cm2. 

 

Page 32, Table 7.3. It would be helpful if the abbreviations in the “Geometry” column were 

defined in a table footnote. 

Page 40, Section 8.2.4, third sentence. The term “Method 3” is not used elsewhere in 

TBD-6001. For connectivity with Tables 8.9 and 8.10, use “horizontal reactor operations” 

instead. 

Page 47, Table 8.24. Presumably the heading for the last two columns should be “calciner,” not 

“trays.” 

Page 53, Table 8.28. Christofano and Harris reference is confusing. The figure in question is 

Figure 16 in C&H and Figure 1 in TBD-6001. The same comment applies to Footnote 2 on 

page 54. 

Page 54, Table 8.29. The terminology “three work week durations” is confusing.
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10.0 REFERENCES 

Battelle 2006. Site Profiles for Atomic Weapons Employers that Worked Thorium and Uranium 

Metals. Battelle-TBD-2006. PNWD-3758, Rev. 0. 

Christofano E. and W.B. Harris. 1960. The Industrial Hygiene of Uranium Refining. Env Health 

1(5):74-96. 

DOE (U.S. Department of Energy) 2003. Recycled Uranium: United States Production, 

Enrichment,and Utilization. DOE/SO-0003. Available on the web at: 

http://www.ssa.doe.gov/sp70/documents/Recycled%20Uranium%20May%202003.pdf . 

Harris, W.B., and I. Kingsley, 1959. The Industrial Hygiene of Uranium Fabrication, Table 5, 

Archives of Industrial Health, Volume 19, reprint, American Medical Association, New York, 

New York. May. [SRDB Ref. ID: 15779]

ICRP (International Commission on Radiation Protection) 1994. Human Respiratory Tract 

Model for Radiological Protection. Publication 66. Ann. ICRP 24(3-1). Oxford: Pergamon 

Press. 

ICRP (International Commission on Radiation Protection) 1968. “ICRP Database of Dose 

Coefficients: Workers and Members of the Public.” V. 2.01. DOCAL Task Group Committee 2 

of the International Commission on Radiation Protection. October 1998. 

Lide, D.R., 1995. CRC Handbook of Chemistry and Physics, 75th edition. CRC Press, Boca 

Raton, Florida. 

NCRP (National Council on Radiation Protection and Measurements) 1987. Ionizing Radiation 

Exposure of the Population of the United States. NCRP Report No. 93. 

NYOO 1949. Health Hazards in NYOO Facilities Producing and Processing Uranium. (A 

Status Report – April 1, 1949), New York Operations Office, U.S. Atomic Energy Commission. 

ORAUT (Oak Ridge Associated Universities Team) 2004. Technical Basis Document for 

Fernald Environmental Management Project. ORAUT-TKBS-0017, Revision 01. ORAU 

Team. Cincinnati, Ohio. 

ORAUT (Oak Ridge Associated Universities Team) 2005. Basis for development of an exposure 

matrix for the Mallinckrodt Chemical Company St. Lewis downtown site and the St. Lewis 

airport site, St. Louis, Missouri, period of operation: 1942–1958. ORAUT-TKBS-0005, 

Revision 01. ORAU Team. Cincinnati, Ohio. 

ORAUT (Oak Ridge Associated Universities Team) 2006. An Exposure Matrix for Linde 

Ceramics Plant (Including Tonawanda Laboratory). QRAUT-TKBS-0025, Rev. 00 PC-1. 

ORAU Team. Cincinnati, Ohio. 
Effective Date: 

February 26, 2008 

Revision No. 

0 - Draft 

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45 of 52 

NOTICE: This report has been reviewed for Privacy Act information and has been cleared for distribution. 

However, this report is pre-decisional and has not been reviewed by the Advisory Board on Radiation and Worker 

Health for factual accuracy or applicability within the requirements of 42 CFR 82.

ORAUT (Oak Ridge Associated Universities Team) 2007. An Exposure Matrix for Harshaw 

Chemical Company, Cleveland Ohio. ORAUT-TKBS-0022, Rev. 00. ORAU Team. 

Cincinnati, Ohio. 

 

Perry, Robert H. and Don W. Green 1984. Perry’s Chemical Enginees’ Handbook, Sixth 

Edition. McGraw-Hill Inc., New York NY. 

SC&A 2005. Review of NIOSH Site Profile for Mallinckrodt Chemical Company, St. Louis 

Downtown Site, St. Louis, MO. SCA-TR-Task1-0002, SC&A, Inc., Vienna, Virginia. January 

31, 2005. 

 

SC&A 2007. Draft Review of Technical Basis Document 6000, SC&A, Inc., Vienna, Virginia. 

September 12, 2007. 

Strom, Daniel F. 2007. Default Assumptions and Methods for Atomic Weapons Employer Dose 

Reconstructions. Battelle-TIB-5000, Rev. 00, Effective date: April 2, 2007. 
Effective Date: 

February 26, 2008 

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APPENDIX A: TABLES 12 AND 13 FROM ORAUT 2005 

Basis for Development of an Exposure Matrix for the 

Mallinckrodt Chemical Company St. Louis Downtown Site and 

the St. Louis Airport Site, St. Louis, Missouri, Period of 

Operation: 1942–1958 
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Table 12. Plant 4 Measured Daily Weighted Average Exposure Concentrations 

Occupation Weighted Average Concentration, Alpha dpm/m3

May-56 Nov-53 Mar-53 Jun-50 Oct-49 Sep-48 May-48 AEC 1949b AEC 1951a 

Magnesium operator 35 70 

Lime blender 35 70 

Slag man 70 105 210 140 

Cage man (handler) 190 3640 189 2940 

Derby unloader 175 245 1,260 280 

Bomb topper 210 280 2,310 840 

Charge firing 140 350 980 910 

Derby chipper 140 350 910 1,890 

Jolter 70 140 490 3,500 

Bomb charger 210 490 3,010 3,640 

Green lead man 70 140 

Cleanup man 140 140 

Furnace tender 70 70 350 560 

Furnace box puller 35 140 560 630 

TA-7 Pilot Plant 980 175 

Brown loader 280 350 2,240 3,360 

Green packer 245 210 1,750 3,990 7,210 

Green miller and mixer 70 140 980 4,690 

Green unloader 210 490 1,540 13,020 

Plant superintendent 7.3 

Technical supervisor 6.6 

Engineers 7.3 9.8 14 

Chief chemist 5.9 

Vacuum fusion chemist 39 

Vacuum fusion technician 59 

Microscopist 18.4 

Chemist 10 

Chemical technician 10 4.6 7 

Foreman 22.5 6.7 12 35 70 175 

Shift foremen 12.4 56 98 175 

Lead operator 25 8.2 19 119 63 --- 

Dingot/bomb, slag grinding oper 85 33 64 X X X X 

Furnace and saw man 17.5 X X X X 

Casting furnace operator 10.8 110 480 5110 

Furnace operator (UF4-derby?) 91 70 570 

HF operator 91 70 570 

UO3 & Brown packer 217 322 2,730 4200 2,730 

Green packing operator 196 315 7,210 4,000; 13,000 

Asst green packing operator 112 133 2,800 

Residue 27.4 

Ceramic 14.8 

Vertical lathe 28.5 

Forge press lead operator 22 

Forge press salt bath man 21.5 

Forge press manipulator (oper) 22.6 
Effective Date: 

February 26, 2008 

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Table 12. Plant 4 Measured Daily Weighted Average Exposure Concentrations 

Occupation Weighted Average Concentration, Alpha dpm/m3

May-56 Nov-53 Mar-53 Jun-50 Oct-49 Sep-48 May-48 AEC 1949b AEC 1951a 

Forge press operator 21.9 

Clerk 5 42 

Guard 7.1 28 

Porter 40 2.7 5.8 56 

Area mechanic --- 22 15 84 112 350 350 

Data from the surveys of 6/50, 10/49, 9/48, and 5/48 is from AEC 1950c; data from the surveys of 3/53 and 11/53 is from 

AEC1954b; and data from the survey of 5/56 is from AEC 1956a. Other data are from the references given in the column 

headings.
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Table 13. Plant 6 Measured Daily Weighted Average Exposure Concentrations 

Occupation Weighted Average Concentration, Alpha dpm/m3

 May-56 May-54 Oct-53 Jan-53 Jan-52 Aug-50 1949 Oct–Nov 1948 May-48 

Digest area lead operator 6 60 36 62 140 84 686 280 

Digest operator 7.3 37 41 52 370 77 399 490 

U-Con man #1 7.3 

U-Con man #2 14 

Feinc operator 6.2 96 38 110 175 154 980 840 

Barium operator 38 130 144 126 280 

Feed operator 40.8 23 100 150 110 126 910 476 

C-3 wash filter operator 79 32 48 120 116 497 476 

C-3 adjustments operator 22 420 120 497 476 

C-3 centrifuge operator 42 630 52 140 567 476 

Ore Room operator 140 170 370 392 350 13,720 4970 

Extraction area lead operator 34 5.4 4 

Ether House operator 11 40 46 

Ether House lead operator 66 154 

Sump recovery operator 8.5 100 76 126 273 364 

Raffinate operator 216 11 8 170 68 154 273 364 

QM-2 (Orange) packager 268 1,961 120 130 130 

Furnace operator 12 33 55 96 150 1,400 5320 24500 

Furnace room sampler 3150 

Reduction area (furn room) lead oper’r 22 25 28 69 54 147 686 

LF-9 (Brown) packager 364 11270 39200 

Nitric acid recovery operator 20 9.6 19 44 35 99 46 364 

Pot Room operator 234 113 45 190 100 336 770 7,770 32200 

Metal dissolver #1 204 

Metal dissolver #2 21 

MGX operator 29 68 52 94 

Utility operator 88 129 94 97 

Miller (Mill Room) X X 12,600 46200 

Pilot Plant group leader 7.5 6.9 3.1 105 91 245 

Pilot Plant lead operator 7.7 8.8 6.1 77 116 105 91 245 

Pilot Plant technician 1,940 9.2 6 77 116 105 91 245 

Production superintendent 7.7 8.8 56 25 

Experimental continuous furnace 8,540 X X X 

Asst. production superintendent 18 21 26 

General/Asst foreman 14 18 30 50 

Foreman 17 21 29 58 161 

Technical supervisor 18 21 25 33 52 161 

Production Office clerk 9.1 12 18 17 27 161 

Production Office secretary 3.4 3.4 27 

Shift foreman 19 25 27 81 96 161 

Cloth & Training Grp Lead Operator 23 25 2520 

Cloth operator 18 19 92 245 665 

Trainers 231 2,520 

Decontamination man 17 22 19 60 99 

Decontamination man 3.5 2.7 2.8 29 

Receiving clerk 5.2 19 4.5 10 99 28 
Effective Date: 

February 26, 2008 

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Table 13. Plant 6 Measured Daily Weighted Average Exposure Concentrations 

Occupation Weighted Average Concentration, Alpha dpm/m3

 May-56 May-54 Oct-53 Jan-53 Jan-52 Aug-50 1949 Oct–Nov 1948 May-48 

Cleanup man 22 

Production Research Lab personnel 3.7 2 5 13 30 12 30 245 

Ledoux Lab asst technician (raffinate) 15.2 8.1 39 

Ledoux Lab technician (raffinate) 12.9 8.1 39 140 420 91 189 

Ledoux Lab technician (K-65) 21 7.5 27 440 1,900 1,400 2,100 

Ledoux Lab technician (MgF2) 21 7.5 27 

Shotgun Lab analyst 24.1 10 27 23 25 239 24 (239) 

Laboratory personnel 42 2.9 30 23 21 

 MCW Laboratory west section 21 30 245 

 MCW Laboratory east section 13 30 245 

Powder sample technician 56.5 217? 448 

Metal room sampler 420 

Outside sampling man 22.5 

Sample Room supervisor 41 245 448 

Laboratory Office personnel 42 2 5.6 

Truck operator 16 19 20 63 75 

Truck operator 20 19 20 63 75 

Warehouse foreman & Asst Foreman 4.2 2.9 6.2 17 70 161 

Warehouse man -- K-65 sampler 350 270 230 84 189 196 

Warehouse man 5.8 10 20 38 46 84 189 196 

Boiler House operator 9.3 7.3 7.5 8.9 2 36 44 

Laundry operator 6.2 19 11 19 4.5 13 

Porter 3.9 17 14 39 

General cleanup 39 

Change room 48 

Lunch room 5.6 

Clothes issue man 18 19 9.4 92 

Chief guard 1.7 14 16 14 1.8 

Security Office 6.3 

Guard 10 13 15 22 1.8 32 

Health Office - personnel (office) 1.6 6.7 15 14 0 11 

Health Office - personnel 8.1 11 15 14 0 7 14 

Health Office personnel 

(plant monitor/health surveyor) 10 15 15 14 0 46 

Health Office person’l (plant monitor) 15 16 15 14 0 

Medic 1.3 3.5 6.3 

Nurse 3.5 6.3 42 99 

Dispensary & Safety 56 56 175 

Instrument Shop technician 12 33 17 40 60 51 252 

Instrument Shop machinist 5.5 44 17 27 60 51 252 

Maintenance/mechanical supervisor 140 13 10 42 38 50 

Maintenance Office clerk 6.5 12 7.7 39 

Area mechanic 24 29 28 

Ore & Furnace Room AM 189 

Digest & feed AM 133 

Raffinate and C-3 AM 161 

Ether & NA House AM 77 

Welders, pipefitters, etc. 98 128 
Effective Date: 

February 26, 2008 

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Table 13. Plant 6 Measured Daily Weighted Average Exposure Concentrations 

Occupation Weighted Average Concentration, Alpha dpm/m3

 May-56 May-54 Oct-53 Jan-53 Jan-52 Aug-50 1949 Oct–Nov 1948 May-48 

Carpenters 66 

Stock Room (Storeroom) foreman 3.7 14 22 13 33 21 

Stock Room clerk 2.6 9 34 15 33 21 

AEC Office personnel 2.2 1.8 6.7 0 Non-det 7.7 33 

AEC Engineer 19 9.9 31 7 

MCW Office personnel 1.5 2 2.9 0.7 0 7 50 

MCW engineer 4.2 4.5 5.4 10 7 15 

MCW Office messenger 15 14 15 40 

MCW Office maintenance 7.5 12 20 10 

MCW Office construction expeditor 9.6 29 

Overall average weighted exposure 41 24 25 56 63 

Notes: The first set of 1948 data (Oct–Nov 1948) is from MCW (MCW 1949d (repeated in AEC 1949b and MCW 1950s), the 

second set (May 1948). The 1949 and 1950 data are from MCW (MCW 1950q) and AEC(AEC 1953); the May 1952, January 

1953, and the October 1953 sets of survey data are from AEC (AEC 1954c); the May 1954 survey data are from AEC (AEC 

1954d); and the May 1956 survey data are from AEC (AEC 1956b). For some occupations (mostly office types), the May 1948 

concentration was the average in the work area, not a DWE, so that the level shown would be higher than what the worker 

actually experienced. 

Exposure Concentrations for Individual Occupations at Plant 6 

with 95th Percentile (Source: TKBS-0005,Table 13)

1

10

100

1,000

10,000

100,000

1946 1947 1949 1950 1952 1953 1954 1956 1957

Concentration (dpm/m3)

DWA Concentration 95th %tile (Table 13) 95th %tile (TBD-6001,Table 27)

Figure A-1. ORAUT 2005 Table 13 DWA Air Concentrations for Job Categories in 

Plant 6 from 1948 to 1956 

The 95th Percentile from Table 13 is compared with 95th Percentile from TBD-6001 Table 8.27. 
Effective Date: 

February 26, 2008 

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Appendix A References: 

AEC (Atomic Energy Commission) 1949b. Health Hazards in NYOO Facilities Producing and 

Processing Uranium. Report by the New York Operations Office Medical Division.18 April 

1949. 

AEC (Atomic Energy Commission) 1950c. Mallinckrodt Chemical Works Plant 4 Occupational 

Exposure to Radioactive Dust. Mallinckrodt-3; 26 July 1950. 

AEC (Atomic Energy Commission) 1953. Mallinckrodt Chemical Works Plant 6 – Ore Room 

Addition – Occupational Exposure to Airborne Contamination. 22 May 1953. 

AEC (Atomic Energy Commission) 1954a. Mallinckrodt Chemical Works Plant 4 Occupational 

Exposure to Airborne Contamination. [HASL-]MCW-17; 11 February 1954. 

AEC (Atomic Energy Commission) 1954b. Mallinckrodt Chemical Works Plant 6 Occupational 

Exposure to Airborne Contamination. [HASL-]MCW-15; January 1954. 

Document No. ORAUT-TKBS-0005 Revision No. 02 Effective Date: 06/14/2007 Page 131 of 

222 

AEC (Atomic Energy Commission) 1954c. Mallinckrodt Chemical Works Plant 6 Occupational 

Exposure to Airborne Contaminants. HASL-MCW-19; 13 August 1954. 

AEC (Atomic Energy Commission) 1954d. Mallinckrodt Chemical Works Plant 6E 

Occupational Exposure to Airborne Contamination. [HASL-]MCW-18; February 1954. 

AEC (Atomic Energy Commission) 1956a. Mallinckrodt Chemical Works Plant 4 Occupational 

Exposure to Airborne Contamination. HASL-MCW-26; 24 September 1956. 

AEC (Atomic Energy Commission) 1956b. Mallinckrodt Chemical Works Plant 6 Occupational 

Exposure to Airborne Contamination. HASL-MCW-27; 12 October 1956. 

MCW (Mallinckrodt Chemical Works) 1949d. Dust Study of Plant Six, October-November 

1948. Memo and report to H. E. Thayer from K. J. Caplan; 21 April 1949. 

MCW (Mallinckrodt Chemical Works) 1950q. No subject. Letter to M. Eisenbud of AEC from 

K. J. Caplan of Mallinckrodt. 4 October 1950. 

MCW (Mallinckrodt Chemical Works) 1950s. Plant Six Dust Study, August 1950. Report; 21 

August 1950.