ORAU TEAM

Dose Reconstruction

Project for NIOSH

Oak Ridge Associated Universities I Dade Moeller I MJW Technical Services

Page 1 of 35

DOE Review Release 05/03/2013

Document Title:

Coworker External Dosimetry Data for the 

Y-12 National Security Complex

Document Number: ORAUT-OTIB-0064

Revision: 02

Effective Date: 04/29/2013

Type of Document: OTIB

Supersedes: Revision 01

ORAUT-OTIB-0047, Revision 

00

Subject Expert(s): George D. Kerr, Janice P. Watkins, and Keith A. McCartney 

Approval: Signature on File Approval Date: 04/22/2013

Matthew H. Smith, Document Owner

Concurrence: Signature on File Concurrence Date: 04/22/2013

John M. Byrne, Objective 1 Manager

Concurrence: Signature on File Concurrence Date: 04/22/2013

Edward F. Maher, Objective 3 Manager

Concurrence: Vickie S. Short Signature on File for Concurrence Date: 04/23/2013

Kate Kimpan, Project Director

Approval: Signature on File Approval Date: 04/29/2013

James W. Neton, Associate Director for Science

New Total Rewrite Revision Page Change

FOR DOCUMENTS MARKED AS A TOTAL REWRITE, REVISION, OR PAGE CHANGE, REPLACE THE PRIOR 

REVISION AND DISCARD / DESTROY ALL COPIES OF THE PRIOR REVISION.
Document No. ORAUT-OTIB-0064 Revision No. 02 Effective Date: 04/29/2013 Page 2 of 35

PUBLICATION RECORD

EFFECTIVE 

DATE

REVISION 

NUMBER DESCRIPTION

08/03/2009 00 Approved new technical information bulletin that provides 

background information on the Y-12 coworker external dosimetry 

data and includes tables with annual values that may be used in the 

process of assigning doses for unmonitored years of employment. 

Incorporates formal internal and NIOSH review comments. Training 

required: As determined by the Objective Manager. Initiated by 

Janice P. Watkins.

12/18/2009 01 Revision to modify Sections 4.0 and 5.0 to be consistent with current 

practices of applying coworker data. Table 7-1c and references to 

Tables 7-1a, 7-1b, and 7-1c were added in Section 7.0. Table 7-1c 

includes the 95th- and 50th-percentile annual doses derived from 

Table 7-1a. Adds details for Table 7-1c in Section 7.0. In Section 

7.0, Table 7-2 was updated to include 1947 to 1949. Incorporates 

formal and NIOSH review comments. Updated Attributions and 

Annotations. Updated references. No sections were deleted. 

Training required: As determined by the Objective Manager. 

Initiated by Keith A. McCartney and Janice P. Watkins.

04/29/2013 02 Revision initiated to update Section 6.1 and add update of previous 

ORAUT-OTIB-0047, Rev 00 as Attachment A. No sections were 

deleted. No changes occurred as a result of formal internal review. 

Incorporates formal NIOSH review comments. Constitutes a total 

rewrite of the document. Training required: As determined by the 

Objective Manager. Initiated by George D. Kerr and Janice P. 

Watkins.
Document No. ORAUT-OTIB-0064 Revision No. 02 Effective Date: 04/29/2013 Page 3 of 35

TABLE OF CONTENTS

SECTION TITLE PAGE

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

1.0 Introduction .................................................................................................................................7

2.0 Purpose and Scope ....................................................................................................................7

3.0 Background.................................................................................................................................7

4.0 General Approach.......................................................................................................................8

5.0 Applications and Limitations .......................................................................................................8

6.0 Coworker Data Development......................................................................................................8

6.1 Adjustment for Missed Dose .........................................................................................10

6.2 Other Considerations ....................................................................................................13

7.0 Coworker Annual Dose Summaries..........................................................................................13

8.0 Attributions and Annotations .....................................................................................................17

References ...........................................................................................................................................19

ATTACHMENT A, EXTERNAL RADIATION MONITORING AT THE Y-12 FACILITY 

DURING THE 1948–1949 PERIOD .......................................................................23

LIST OF TABLES

TABLE TITLE PAGE

6-1 Comparisons of distributions of annual gamma doses and annual skin doses in 1962..............9

6-2 Exchange frequencies for film badge dosimeters as a function of time....................................12

6-3 MDLs and assigned MDL doses for film used to measure gamma and beta doses.................12

6-4 Potential missed dose from external radiation exposure during the film badge 

dosimetry program....................................................................................................................12

7-1a Parameters for lognormal prediction density, 1947 to 1951 .....................................................13

7-1b Annual coworker external doses for 1952 to 1979 with gamma and beta doses 

adjusted for missed dose by the method in ORAUT-OTIB-0020 ..............................................15

7-1c Annual coworker external doses for 1947 to 1951 based on combined quarterly results 

from Table 7-1a.........................................................................................................................16

7-2 Annual coworker external doses with gamma and beta doses modified for construction 

trade workers in accordance with ORAUT-OTIB-0052 .............................................................17

A-1 Number of total and non-NR weekly records by month from Y-12 external monitoring 

file for 1948 and 1949 ...............................................................................................................27

A-2 Number of PIC weekly records from Y-12 monthly external monitoring file for 1948 and 

1949 and number of these records equal to zero .....................................................................28

A-3 Number of sensitive film–open window (R2) weekly records from Y-12 monthly external 

monitoring file for 1948 and 1949 and number of these records equal to zero and to 30 

mrem.........................................................................................................................................28
Document No. ORAUT-OTIB-0064 Revision No. 02 Effective Date: 04/29/2013 Page 4 of 35

A-4 Number of sensitive film–cadmium shielded weekly records from Y-12 monthly external 

monitoring file for 1948 and 1949 and number of these records equal to zero and to 30 

mrem.........................................................................................................................................29

A-5 Number of insensitive film–cadmium shielded weekly records from Y-12 monthly 

external monitoring file for 1948 and 1949 and number of these records equal to zero 

and to 30 mrem.........................................................................................................................29

A-6 Means of weekly recorded doses in the quarter from Y-12 external monitoring file, 1948 

and 1949...................................................................................................................................33

A-7 Comparison of mean weekly doses from Table A-6 scaled up to a full quarter and 

mean quarterly dose estimates from regression approach.......................................................33

A-8 Comparison of mean weekly doses from Table A-6 with an adjustment for doses 

assigned when below MDL and mean quarterly dose estimates from regression 

approach...................................................................................................................................34

LIST OF FIGURES

FIGURE TITLE PAGE

6-1 Comparison of cumulative skin doses in rem from UCNC (1957) and the CER 

database for 65 foundry workers, 1952 to 1956 .......................................................................10

6-2 Percentage of null penetrating and nonpenetrating doses among the recorded quarterly 

doses, 1950 to 1964 .................................................................................................................11

6-3 Percentage of null penetrating and nonpenetrating doses among the recorded quarterly 

doses, 1965 to 1979 .................................................................................................................11

A-1 Sums of Y-12 weekly recorded doses by month and year for 1948 and 1949 .........................30

A-2 Statistics for Y-12 weekly R1 doses by month and year...........................................................30

A-3 Statistics for Y-12 weekly R2 doses by month and year...........................................................31

A-4 Statistics for Y-12 weekly R3 doses by month and year...........................................................31

A-5 Statistics for Y-12 weekly R4 doses by month and year...........................................................32
Document No. ORAUT-OTIB-0064 Revision No. 02 Effective Date: 04/29/2013 Page 5 of 35

ACRONYMS AND ABBREVIATIONS

CER Center for Epidemiologic Research

DOE U.S. Department of Energy

E(dose) Expected value of dose in the statistical sense; i.e., the mean dose on the original 

scale

EU enriched uranium

GM geometric mean

GSD geometric standard deviation

HP health physics

hr hour

ID identifier

keV kiloelectron-volt (1,000 electron-volts)

LANL Los Alamos National Laboratory

MDL minimum detectable level

MeV megaelectron-volt, 1 million electron-volts

mm millimeter

mR milliroentgen, a unit of radiation exposure

mrem millirem

NIOSH National Institute for Occupational Safety and Health

NR no reading/no response

ORAU Oak Ridge Associated Universities

PIC pocket ionization chamber

R1 PIC reading

R2 sensitive film reading under open window of film badge

R3 sensitive film reading under 1-mm-thick cadmium shield of film badge

R4 insensitive film reading under 1-mm-thick cadmium shield of film badge

SRDB Ref ID Site Research Database Reference Identification (number)

SSN Social Security Number

TEC Tennessee Eastman Corporation

TBD technical basis document

TIB technical information bulletin

TLD thermoluminescent dosimeter

UCC Union Carbide Corporation

U.S.C. United States Code

wk week
Document No. ORAUT-OTIB-0064 Revision No. 02 Effective Date: 04/29/2013 Page 6 of 35

Y-12 Y-12 Plant, now the Y-12 National Security Complex

yr year

§ section or sections
Document No. ORAUT-OTIB-0064 Revision No. 02 Effective Date: 04/29/2013 Page 7 of 35

1.0 INTRODUCTION

Technical information bulletins (TIBs) are not official determinations made by the National Institute for 

Occupational Safety and Health (NIOSH) but are rather general working documents that provide 

historical background information and guidance to assist in the preparation of dose reconstructions at 

particular sites or categories of sites. They will be revised in the event additional relevant information 

is obtained about the affected site(s). TIBs may be used to assist NIOSH staff in the completion of 

individual dose reconstructions.

In this document, the word “facility” is used as a general term for an area, building, or group of 

buildings that served a specific purpose at a site. It does not necessarily connote an “atomic weapons 

employer facility” or a “Department of Energy (DOE) facility” as defined in the Energy Employees 

Occupational Illness Compensation Program Act of 2000 [42 U.S.C. § 7384l(5) and (12)].

2.0 PURPOSE AND SCOPE

The purpose of this TIB is to provide information that will enable Oak Ridge Associated Universities 

(ORAU) Team dose reconstructors to assign doses based on site coworker data to workers at the 

Y-12 Plant who have limited or no monitoring data. The data in this TIB are to be used in conjunction 

with ORAUT-OTIB-0020, Use of Coworker Dosimetry Data for External Dose Assignment (ORAUT 

2011a). This TIB is for use in reconstructions for the period from January 1947 to December 1979.

The purpose of Attachment A is to verify that the coworker data in Table 7-1a provide conservative 

but realistic estimates of the radiation doses to Y-12 workers who were not routinely monitored for 

exposure to external fields of gamma radiation and beta particles prior to 1952. This attachment 

analyzes the limited data available for Y-12 workers who were monitored for exposure to external 

radiation during 1948 and 1949.

Attributions and annotations within the text of this report are indicated by bracketed callouts and used 

to identify the source, justification, or clarification of the associated information. The attributions and 

annotations are presented in Section 8.0.

3.0 BACKGROUND

The ORAU Team is conducting a series of coworker data studies to permit dose reconstructors to 

complete cases for which external and/or internal monitoring data are unavailable or incomplete. 

Such cases can fall into one of several categories, as follows:

• The worker was unmonitored and, even by today’s standards, did not need to be monitored 

(e.g., a nonradiological worker).

• The worker was unmonitored but by today’s standards would have been monitored.

• It is possible that the worker was monitored, but if so the data are not available.

• There is some information available for the worker, but it is insufficient to permit a dose 

reconstruction.

The Union Carbide Corporation Nuclear Division assumed the management of the Y-12 Plant in May 

1947, and the Plant mission changed from the electromagnetic enrichment of uranium using calutrons 

to the processing and fabrication of uranium and other nuclear materials (ORAUT 2007). The first 

experience with the machining of uranium metal at the Y-12 Plant was in December 1947 in a shop in 

Building 9766 (Emlet 1952). In the spring of 1948, steps were taken for the transfer of certain weapon 
Document No. ORAUT-OTIB-0064 Revision No. 02 Effective Date: 04/29/2013 Page 8 of 35

fabrication functions from Los Alamos to Y-12 Plant facilities, which were established in Building 9212 

where chemical processing of uranium had long occurred. At that time, the responsibility for the study 

and monitoring of the uranium machining operations was transferred from a Special Hazards Group to 

a Health Physics (HP) Department in the Medical Division (Emlet 1952).

The HP Department started a film badge dosimetry program in 1948 to monitor external radiation 

exposures to Y-12 workers in the Assay Laboratories, Radiographic Shop, Spectrographic Shop, and 

Machine Shops, which handled uranium metals (Struxness 1948a). The external monitoring data for 

1948 and 1949 are not readily available by Social Security Number (SSN), and have not been 

supplied by Y-12 in response to requests under EEOICPA (Souleyrette 2003). Attachment A contains 

information about the external monitoring data for 1948 and 1949 that are available from previous 

epidemiological studies by the ORAU Center for Epidemiologic Research (CER). These CER data 

have been placed on the secure data server at the ORAU Cincinnati Operations Office for use in dose 

reconstructions for workers at the Y-12 facility. In addition, the data on the server have been linked to 

each worker’s badge identification number and SSN (see Attachment A).

An extensive documentation of the worker radiological programs beginning in the 1950s is provided in 

the Recycled Uranium Mass Balance Project for the Y-12 National Security Complex Site Report

(BWXT Y-12 2000). The film badge dosimetry program was expanded in 1950 to include all Y-12 

personnel who worked with (1) depleted uranium metal, (2) discrete sources of gamma rays or beta 

particles, (3) X-rays, and (4) materials that were contaminated with fission products (McLendon 1960). 

This external radiation dosimetry policy of monitoring only the Y-12 workers who were involved with 

those four types of radioactive materials (about 10% to 20% of all workers) was continued until 1961 

(ORAUT 2013). In 1961, a new policy was instituted that required all Y-12 workers to be monitored 

for external radiation exposure with film dosimeters, which were integrated into the worker’s 

identification badges and contained components for both routine and accident-related dosimetry. The 

use of film dosimeters ended in 1979 when they were largely replaced by thermoluminescent 

dosimeters (TLDs) (McLendon et al. 1980; West 1993). The data in this TIB address penetrating 

gamma radiation and nonpenetrating electron and low-energy photon radiation.

4.0 GENERAL APPROACH

As described in ORAUT (2011a), the general approach to the application of coworker data to cases 

without external monitoring data is to assign either the 50th- or 95th-percentile doses with the intent 

that the assigned doses represent, but do not underestimate, the doses that would have been 

assigned had the worker been monitored.

5.0 APPLICATIONS AND LIMITATIONS

Some Y-12 workers could have worked at one or more other major sites in the DOE complex during 

their employment histories. Therefore, the data in this TIB must be used with caution to ensure that, 

for likely noncompensable cases, unmonitored external doses from multiple site employments have 

been overestimated. This typically requires the availability of the recorded doses or TIBs for external 

coworker dosimetry data for all relevant sites.

External onsite ambient dose should be applied as specified in the latest revision of ORAUT-PROC0060, Occupational Onsite Ambient Dose Reconstruction for DOE Sites (ORAUT 2006).

6.0 COWORKER DATA DEVELOPMENT

From 1978 through the early 1990s, the Y-12 site delivered electronic files of worker data to the 

ORAU CER as a resource for the Health and Mortality Studies for DOE and its predecessor agencies 

(Watkins et al. 1993). Files that were received on magnetic tapes contained records for more than 
Document No. ORAUT-OTIB-0064 Revision No. 02 Effective Date: 04/29/2013 Page 9 of 35

17,000 Y-12 workers. The records included doses from gamma, beta, and neutron exposures as well 

as other relevant information. Due to changes over time in recordkeeping practices and procedures 

at Y-12, the files were in several similar but not identical formats. CER transferred all the data from 

tape to disk and later constructed a carefully linked relational database with a standardized file format. 

Since 2002, the data have resided in a Structured Query Language database. The data that were 

used in this work consist of more than 425,000 records for 1950 through 1979. All records contain the 

data elements from original Y-12 files, which included first, middle, and last names; plant badge 

number; SSN; year; quarter; quarterly summations of dose readings for different monitoring periods 

(i.e., weekly, monthly, or quarterly); and other work history and demographic data. The quarterly 

summations give results in millirem for all beta, gamma, and neutron doses. Although each record 

has a flag to note an error condition, this flag is null for years before 1980 and so is not relevant for 

the film badge period. The external radiation doses that are being provided to NIOSH are effectively 

the same as those in the CER database.

The validity of the CER database was confirmed by a number of comparisons with summaries of film 

badge dose data in Y-12 internal correspondence and Y-12 HP progress reports [1]. The progress 

reports were produced with varying frequency (monthly, quarterly, and semiannually) and have been 

retrieved from as early as September 1947 (Murray 1947). Examples of such comparisons are 

provided in Table 6-1 and Figure 6-1. The left-hand portion of Table 6-1 lists the distribution of annual 

gamma doses and annual skin doses (i.e., annual gamma dose plus annual beta dose) to Y-12 

workers during 1962 from a progress report for the fourth quarter of 1962 (UCNC 1963a). The righthand portion of Table 6-1 lists the same annual dose distributions from the CER database. The two 

sets of annual dose distributions in Table 6-1 are in excellent agreement. The second example, 

shown in Figure 6-1, is from internal correspondence on the radiation doses to Y-12 foundry workers 

(UCNC 1957). The open circles in Figure 6-1 represent a comparison of cumulative skin doses to 65 

Y-12 foundry workers over the 5-year period from 1952 to 1956 from UCNC (1957) and those derived 

from sums of 194 person-years of recorded skin dose data over the same period and for the same 65 

Y-12 foundry workers. The two sets of cumulative skin doses have high correlation as Figure 6-1 

shows. The Pearson correlation coefficient, which assumes a bivariate normal distribution, is 0.841 

(Pearson 1896), and the nonparametric Spearman (rank) correlation coefficient is 0.975 (Spearman 

1904). Overall, the CER database was found to be acceptable for dose reconstruction purposes and 

for the development of coworker doses at the Y-12 Plant for 1952 to 1979.

Table 6-1. Comparisons of distributions of annual gamma doses and annual skin 

doses (gamma plus beta radiation) in 1962.

HP progress report (UCNC 1963a) CER database

Dose range 

(mrem)

Number of workers Dose range 

(mrem)

Number of workers

Gamma Skin dose Gamma Skin dose

<1,000 5,787 5,108 0–1,000 5,771 4,990

2,000 6 324 1,001–2,000 20 403

3,000 1 173 2,001–3,000 2 197

4,000 0 91 3,001–4,000 1 98

5,000 0 40 4,001–5,000 0 43

6,000 0 25 5,001–6,000 0 28

7,000 0 15 6,001–7,000 0 16

8,000 0 9 7,001–8,000 0 10

9,000 0 6 8,001–9,000 0 6

10,000 0 2 9,001–10,000 0 2

11,000 0 0 10,001–11,000 0 1

12,000 0 1 11,001–12,000 0 0

>12,000 0 0 >12,000 0 0

Total 5,794 5,794 Total 5,794 5,794
Document No. ORAUT-OTIB-0064 Revision No. 02 Effective Date: 04/29/2013 Page 10 of 35

6.1 ADJUSTMENT FOR MISSED DOSE

OCAS-IG-001, External Dose Reconstruction Implementation Guideline (NIOSH 2007), states that 

missed doses are to be assigned for null dosimeter readings to account for the possibility that doses 

Figure 6-1. Comparison of cumulative skin doses in 

rem (Srem) from UCNC (1957) and the CER 

database for 65 foundry workers, 1952 to 1956.

were received but either not recorded by the film badge dosimeter or not reported by the site. These 

missed doses are calculated by multiplying the minimum detectable level (MDL) of the dosimeters by 

the number of null badge readings and summing the results; these values are used as the 95thpercentile values of a lognormal distribution for calculating probability of causation for a specific 

cancer.

The assignment of missed doses for monitored workers is particularly significant for Y-12 workers, as 

Figures 6-2 and 6-3 show, because historically there was a high percentage of null dosimeter results 

for this site. The large number of null results in the monitoring data is largely due to the weekly 

exchange of film badge dosimeters for monitored workers in the early 1950s and to the monitoring of 

the entire Y-12 workforce with film badge dosimeters staring in 1961. Because Y-12 workers with null 

monitoring data should be assigned missed dose, including those workers who probably had no 

potential for exposure to external radiation during their employment, the assignment of doses to Y-12 

workers with no monitoring data based on coworker data must also account for the assignment of 

missed dose [2].

The magnitude of missed dose depended on both the exchange frequency and the MDL of the film 

badge dosimeters in use during the time of interest. Table 6-2 provides information of the exchange 

frequencies of the film badge dosimeters from 1948 through 1979, and Table 6-3 gives the MDLs 

along with the assigned MDL dose during the corresponding periods. It is important to note that the 

MDL and the assigned MDL dose to workers changed significantly with time. As noted, the dates in 

Table 6-2 and 6-3 are approximate because the changes did not occur for all Y-12 employees at the 

same time. During 1950 and 1951 the beta and gamma doses were recorded as zero if they were 
Document No. ORAUT-OTIB-0064 Revision No. 02 Effective Date: 04/29/2013 Page 11 of 35

less than the MDL of 30 mrem (see Table 6-3). As a result, there was only one positive gamma dose 

of 65 mrem among the 268 recorded doses for 148 monitored workers in 1950; no positive gamma 

doses were recorded for the 184 monitored workers in 1951. There were also no beta doses 

recorded for these monitored workers in either 1950 or 1951 (see Figure 6-2).

Figure 6-2. Percentage of null penetrating (gamma) and nonpenetrating 

(beta) doses among the recorded quarterly doses, 1950 to 1964.

Figure 6-3. Percentage of null penetrating (gamma) and nonpenetrating 

(beta) doses among the recorded quarterly doses, 1965 to 1979.
Document No. ORAUT-OTIB-0064 Revision No. 02 Effective Date: 04/29/2013 Page 12 of 35

The data in Tables 6-2 and 6-3 were used in the development of the data in Table 6-4, which lists the 

maximum annual missed gamma and beta doses by period. Although some workers might have been 

on a film dosimeter exchange cycle that was less or more frequent than the typical cycle (ORAUT 

2009a), the great majority of Y-12 workers were on the schedule in Table 6-2. Therefore, the values 

in Table 6-4 are appropriate for the adjustment of reported coworker doses to account for missed 

dose.

Table 6-2. Exchange frequencies for film badge dosimeters 

as a function of time.

a

Periodb Exchange frequency

May 1948–September 1958 Weekly

October 1958–December 1960 Monthly

January 1961–December 1979 Quarterly

a. Attachment A, West (1993), McLendon (1958), and Reavis (1958).

b. Dates are approximate because changes did not occur for all employees 

at the same time.

Table 6-3. MDLs and assigned MDL doses (mrem) for film 

used to measure gamma and beta doses.

a

Periodb MDL Assigned dose

May 1948–December 1949 30 30c

January 1950–December 1951 30 0

January 1952–September 1952 50 50c

October 1952–December 1952 43 43c

January 1953–June 1954 50 50c

July 1954–December 1954 30 30c

January 1955–December 1957 30 15d

January 1958–October 1979 30 Not applicablee

a. Attachment A; West (1993).

b. Dates are approximate because the changes did not occur for all 

employees at the same time.

c. Assigned to gamma dose for those workers with a high potential for 

exposure to gamma rays or to beta dose for those workers with a 

high potential for exposure to beta particles (or soft X-rays) if 

shielded and open-window film readings were less than the MDL.

d. Assigned to beta dose if shielded and open-window film readings 

were less than the MDL.

e. The actual shielded and open-window film readings were used to 

calculate the gamma and beta doses even when the film readings 

were less than the MDL.

Table 6-4. Potential missed dose (mrem) from external radiation exposure during the film 

badge dosimetry program.

Period

Gamma 

MDL

Beta 

MDL

Exchange 

frequency

Maximum annual missed dose 

Gamma (mrem) Beta (mrem)

May 1948–Dec 1949 30 30 Weekly 1,560 1,560

Jan 1950–Dec 1951 30 30 Weekly 1,560 1,560

Jan 1952–Sep 1952 50 50 Weekly 2,600 2,600

Oct 1952–Dec 1952 43 43 Weekly 2,236 2,236

Jan 1953–Jun 1954 50 50 Weekly 2,600 2,600

Jul 1954–Sep 1958 30 30 Weekly 1,560 1,560

Oct 1958–Dec 1960 30 30 Monthly 360 360

Jan 1961–Dec 1979 30 30 Quarterly 120 120
Document No. ORAUT-OTIB-0064 Revision No. 02 Effective Date: 04/29/2013 Page 13 of 35

6.2 OTHER CONSIDERATIONS

Certain aspects of the external dosimetry practices at the Y-12 Plant that are documented in the 

external radiation technical basis document (TBD) for the Y-12 site (ORAUT 2009a) were considered 

in the analysis of the site data. These include:

• In some cases, values less than the dosimeter MDL were reported by the site. A lower 

detection limit of approximately 10 mrem was possible if an experienced technician evaluated 

the exposed film with special care (Morgan 1961). Therefore, values as low as 10 to 20 mrem 

were reported even though the MDL was considered to be 30 mrem or more.

• Before 1961, dosimeter use was not expressly required for all workers. Badges were typically 

provided only to people who entered a radiation area, and the badges were worn based on an 

honor system rather than on a strict requirement. A review of worker data indicates that most 

workers did wear the badges when they were provided.

As Section 7.0 describes, the approach for the development of coworker dose summaries was 

favorable to claimants, and this approach should account for any underestimates of doses to radiation 

workers at the Y-12 site based on these considerations.

7.0 COWORKER ANNUAL DOSE SUMMARIES

Based on the information and approaches described above, Y-12 coworker annual external dosimetry 

summaries were developed for use in the evaluation of external dose for workers who were potentially 

exposed to workplace radiation but for whom DOE could not provide monitoring data. These 

summaries were developed as follows:

Table 7-1a

Table 7-1a provides quarterly data for beta and gamma doses from the third quarter of 1947 through 

the fourth quarter 1951 based on subgroup regression analysis (ORAUT 2007, 2013). Percentile 

values in Table 7-1c are derived from these data.

Table 7-1a. Parameters for lognormal prediction density, 1947 to 1951.

Year Qtr μ σ GM (mrem) GSD

E(dose) 

(mrem)

Gamma dosea

1947 3 5.2684 1.1710 194.1093 3.2254 385.3264

4 5.2380 1.1710 188.3017 3.2251 373.7602

1948 1 5.2077 1.1709 182.6679 3.2248 362.5419

2 5.1773 1.1708 177.2026 3.2245 351.6610

3 5.1469 1.1707 171.9009 3.2243 341.1072

4 5.1165 1.1706 166.7578 3.2240 330.8709

1949 1 5.0862 1.1706 161.7685 3.2238 320.9423

2 5.0558 1.1705 156.9285 3.2235 311.3123

3 5.0254 1.1704 152.2334 3.2233 301.9717

4 4.9950 1.1703 147.6787 3.2230 292.9120

1950 1 4.9647 1.1703 143.2603 3.2228 284.1247

2 4.9343 1.1702 138.9740 3.2226 275.6015

3 4.9039 1.1701 134.8161 3.2224 267.3344

4 4.8735 1.1701 130.7825 3.2222 259.3159

1951 1 4.8432 1.1700 126.8696 3.2220 251.5383

2 4.8128 1.1699 123.0738 3.2217 243.9945

3 4.7824 1.1699 119.3915 3.2216 236.6773
Document No. ORAUT-OTIB-0064 Revision No. 02 Effective Date: 04/29/2013 Page 14 of 35

Year Qtr μ σ GM (mrem) GSD

E(dose) 

(mrem)

4 4.7520 1.1698 115.8194 3.2214 229.5801

Beta doseb

1947 3 6.8231 1.3687 918.82 3.9304 2,344.4

4 6.8075 1.3687 904.61 3.9304 2,308.2

1948 1 6.7917 1.3687 890.41 3.9304 2,272.0

2 6.7756 1.3687 876.20 3.9304 2,235.7

3 6.7593 1.3687 862.00 3.9304 2,199.5

4 6.7426 1.3687 847.79 3.9304 2,163.2

1949 1 6.7257 1.3687 833.59 3.9304 2,127.0

2 6.7085 1.3687 819.38 3.9304 2,090.7

3 6.6911 1.3687 805.17 3.9304 2,054.5

4 6.6733 1.3687 790.97 3.9304 2,018.2

1950 1 6.6551 1.3687 776.76 3.9304 1,982.0

2 6.6367 1.3687 762.56 3.9304 1,945.7

3 6.6179 1.3687 748.35 3.9304 1,909.5

4 6.5987 1.3687 734.15 3.9304 1,873.2

1951 1 6.5792 1.3687 719.94 3.9304 1,837.0

2 6.5592 1.3687 705.73 3.9304 1,800.7

3 6.5389 1.3687 691.53 3.9304 1,764.5

4 6.5181 1.3687 677.32 3.9304 1,728.2

a. From ORAUT-OTIB-0044 (ORAUT 2013).

b. From ORAUT-OTIB-0046 (ORAUT 2007).

Table 7-1b

1. The gamma and beta doses available from CER (see Section 6.0) were converted to annual 

data by summing the reported quarterly data for 1952 to 1979. Consistent with the guidelines 

in ORAUT-OTIB-0020 (ORAUT 2011a), gamma and beta doses for individuals with fewer than 

4 quarters of data for a particular year were converted to annual doses by extrapolation: One 

quarterly result was multiplied by 4; the sum of two quarterly results was multiplied by 2; and 

the sum of 3 quarterly results was multiplied by 1.333.

2. For the gamma doses, one-half of the year’s maximum possible annual missed dose was 

added to each annual dose from Step 1 using the MDLs and badge exchange frequencies in 

Tables 6-2 and 6-3. The added amount for a quarter was the MDL/2 multiplied by the badge 

exchange frequency. If a reported quarterly dose was positive, the badge exchange frequency 

was reduced by 1 because it is not possible that all individual badge results were zero if a 

positive annual dose was reported. Note that this is not the procedure in OCAS-IG-001 

(NIOSH 2007, Section 2.1.2.3), which applies to situations in which the number of zero 

measurements cannot be determined, as occurs for Y-12 doses before 1961.

3. The 50th- and 95th-percentile annual gamma and beta dose values were derived from the 

gamma and beta doses in Step 2 by ranking the data and extracting percentiles for each year.

4. The results in Table 7-1b are presented for both gamma and beta doses. The gamma dose 

percentiles should be used for selected Y-12 workers with limited or no monitoring data using 

the methods in Section 7.0 of ORAUT-OTIB-0020 (ORAUT 2011a). The percentiles for beta 

doses should be applied only to Y-12 workers who were employed in areas with beta dose 

potential.
Document No. ORAUT-OTIB-0064 Revision No. 02 Effective Date: 04/29/2013 Page 15 of 35

Table 7-1b. Annual coworker external doses (mrem) for 1952 to 1979 with 

gamma and beta doses adjusted for missed dose by the method in 

ORAUT-OTIB-0020 (ORAUT 2011a).

Year

Gamma dose Beta dose Number of 

monitored 

workers

95th 

percentile

50th 

percentile

95th 

percentile

50th 

percentile

1952 3,453 2,419 5,623 1,300 497

1953 4,216 1,300 7,429 2,475 386

1954 3,608 1,300 11,843 3,039 681

1955 2,572 780 11,482 3,241 623

1956 1,810 961 8,404 2,541 729

1957 1,556 934 7,777 2,384 795

1958 1,797 1,065 4,470 1,745 995

1959 1,173 448 3,928 875 1,265

1960 1,124 423 5,093 894 1,335

1961 491 155 2,322 91 5,869

1962 519 171 2,257 101 5,793

1963 360 58 1,464 82 5,789

1964 397 72 1,578 97 5,592

1965 382 110 1,083 70 5,138

1966 478 87 1,185 118 4,730

1967 372 71 1,014 81 5,016

1968 271 141 897 48 5,580

1969 364 127 624 52 6,319

1970 366 122 863 53 7,122

1971 325 110 469 47 7,055

1972 208 57 586 48 6,880

1973 198 53 510 60 6,503

1974 366 93 614 60 5,836

1975 171 54 613 60 5,282

1976 179 58 410 89 5,062

1977 158 52 350 57 5,360

1978 219 86 385 57 5,573

1979 156 60 571 71 5,964

Table 7-1c

1. The quarterly gamma and beta doses in Table 7-1a were combined into annual dose 

distributions using Monte Carlo techniques. Dose for 1947 was doubled to normalize the data 

to one full year of exposure.

2. Missed dose was not added to the resultant annual dose distributions from Step 1 above. The 

original analysis in ORAUT-OTIB-0044 (ORAUT 2013) includes an analysis of missed dose. 

Therefore, additional missed dose was not added to the quarterly dose distributions.

3. The 50th- and 95th-percentile annual gamma and beta dose values were derived from the 

resultant lognormal distributions from Step 1.

4. The results in Table 7-1c are presented for both gamma and beta doses. The gamma dose 

percentiles should be used for selected Y-12 workers with limited or no monitoring data using 

the methods in Section 7.0 of ORAUT-OTIB-0020 (ORAUT 2011a). The percentiles for beta 

doses should be applied only to Y-12 workers who were employed in areas with beta dose 

potential.
Document No. ORAUT-OTIB-0064 Revision No. 02 Effective Date: 04/29/2013 Page 16 of 35

Table 7-1c. Annual coworker external doses (mrem) for 

1947 to 1951 based on combined quarterly results from 

Table 7-1a.

Year

Gamma dose Beta dose

95th 

percentile

50th 

percentile

95th 

percentile

50th 

percentile

1947 4,427 1,005 29,514 5,180

1948 3,345 1,089 23,471 6,222

1949 2,981 962 22,343 5,830

1950 2,592 851 20,713 5,487

1951 2,373 762 18,861 4,975

5. Beta dose 95th-percentile values for 1947 to 1951 might need adjustment for dose 

reconstruction. These values are above or in close proximity to the yearly radiological 

protection guidelines for that era, 25 rem for 1947 and 1948 and 15 rem for 1949 to 1951 

(ORAUT 2007). There were no reported beta doses above these yearly radiation protection 

guidelines for 1947 to 1951 (Attachment A, ORAUT 2007).

Doses to organs that are affected only by gamma radiation (e.g., organs other than the skin, breast, 

and testes) should be calculated based only on the gamma dose columns in Table 7-1b and 7-1c in 

combination with the appropriate organ dose conversion factors (NIOSH 2007). Doses to the skin, 

breast, and testes (or any other cancer location that could be affected by beta radiation) should be 

determined based on both the gamma and beta columns. Gamma doses should be assigned as 

photons with energy ranges consistent with information in the external dosimetry TBD for the Y-12 site 

(ORAUT 2009a), and beta doses should be assigned as electrons with energy greater than 15 keV (or 

photons less than 30 keV if appropriate) with corrections to account for clothing attenuation or other 

relevant considerations (ORAUT 2005). Work with depleted uranium has been responsible for the 

majority of the beta (or nonpenetrating) doses at the Y-12 facility (UCNC 1963a,b; Henderson 1991; 

Ashley et al. 1995; ORAUT 2007).

As footnoted in Table 6-3 and demonstrated in the example in Section 6.2, significant amounts of 

missed dose were already added to the recorded dose of Y-12 workers in the late 1940s and early 

1950s. With the addition of more missed dose to these workers’ recorded doses as outlined above, 

the amount of missed dose that was added to some of these workers’ recorded doses from January 

1952 to September 1952 and from January 1953 to June 1954 could be as large as 75 mrem/wk, or 

3.9 rem/yr. Therefore, the Y-12 coworker doses in this report are expected to be favorable to 

claimants for the period before the start of the monthly and quarterly exchange of the film badge 

dosimeters in the late 1950s and early 1960s (see Table 6-2).

Table 7-2 contains the 50th- and 95th-percentile values of the gamma dose for construction trade 

workers who meet the criteria in Section 3.0 of ORAUT-OTIB-0052 (ORAUT 2011b). These 

percentile values, which are based on the annual values in Tables 7-1b and 7-1c, were calculated 

using the guidance in Section 8.0 of ORAUT-OTIB-0052 and should not be used for workers who do 

not meet the specified criteria.
Document No. ORAUT-OTIB-0064 Revision No. 02 Effective Date: 04/29/2013 Page 17 of 35

Table 7-2. Annual coworker external doses (mrem) with gamma 

and beta doses modified for construction trade workers in 

accordance with ORAUT-OTIB-0052 (ORAUT 2011b).

Year

Gamma dose Beta dose

95th 

percentile

50th 

percentile

95th 

percentile

50th 

percentile

1947 6,198 1,407 29,514 5,180

1948 4,684 1,525 23,471 6,222

1949 4,174 1,347 22,343 5,830

1950 3,629 1,191 20,713 5,487

1951 3,322 1,067 18,861 4,975

1952 4,324 2,877 5,623 1,300

1953 5,392 1,300 7,429 2,475

1954 4,542 1,300 11,843 3,039

1955 3,294 780 11,482 3,241

1956 2,227 1,039 8,404 2,541

1957 1,873 1,002 7,777 2,384

1958 2,210 1,185 4,470 1,745

1959 1,576 561 3,928 875

1960 1,508 526 5,093 894

1961 669 199 2,322 91

1962 708 221 2,257 101

1963 486 63 1,464 82

1964 538 83 1,578 97

1965 517 136 1,083 70

1966 651 104 1,185 118

1967 503 81 1,014 81

1968 362 179 897 48

1969 492 160 624 52

1970 494 153 863 53

1971 437 136 469 47

1972 273 62 586 48

1973 259 56 510 60

1974 494 112 614 60

1975 221 58 613 60

1976 233 63 410 89

1977 203 55 350 57

1978 289 102 385 57

1979 200 60 571 71

8.0 ATTRIBUTIONS AND ANNOTATIONS

Where appropriate in this document, bracketed callouts have been inserted to indicate information, 

conclusions, and recommendations provided to assist in the process of worker dose reconstruction. 

These callouts are listed here in the Attributions and Annotations section, with information to identify 

the source and justification for each associated item. Conventional References, which are provided in

the next section of this document, link data, quotations, and other information to documents available 

for review on the Project’s Site Research Database (SRDB).

[1] Tankersley, William G. Oak Ridge Associated Universities. Industrial Hygienist. March 2007.

Comparisons were made between the CER database and original plant documents in relation 

to total number of workers monitored by year and department, cumulative annual doses for 

individuals and groups, magnitude of particularly outstanding results, specific years of 

monitoring for individuals, count of doses within or exceeding regulatory limits, average annual 
Document No. ORAUT-OTIB-0064 Revision No. 02 Effective Date: 04/29/2013 Page 18 of 35

exposures for multiple years, count of monitoring results within dose ranges, and others. 

Results of the comparisons provided strong evidence of the reliability and completeness of the 

CER database. Specific documents that contained the data with which comparisons were 

carried out included the following:

• Y-12 Plant Health Physics Progress Report for Period July 1, 1951 to December 31, 

1951 (Ballenger 1952);

• Y-12 Plant Quarterly Health Physics Report, Third Quarter CY 1962 (UCNC 1963b);

• Y-12 Plant Quarterly Health Physics Report, Fourth Quarter CY 1962 (UCNC 1963a); 

and

• “Cumulative External Radiation Exposures” (McLendon 1957).

[2] Watkins, Janice P. Oak Ridge Associated Universities. Biostatistician. March 2007.

The External Dose Reconstruction Implementation Guideline (NIOSH 2007) mandates the 

assignment of missed dose for periods of employment when badge readings were zero 

regardless of whether the worker’s tasks involved potential for external radiation exposure. To 

maintain consistency, doses based on coworker data for unmonitored periods of employment 

should also be augmented to account for possible missed dose.
Document No. ORAUT-OTIB-0064 Revision No. 02 Effective Date: 04/29/2013 Page 19 of 35

REFERENCES

Ashley, J. C., J. E. Turner, M. L. Souleyrette, R. S. Bogard, and K. L. McMahan, 1995, A Technical 

Study of TLD Beta Calibration Factor for Exposure to Depleted Uranium, Y/DQ-59, Y-12 Plant, 

Oak Ridge, Tennessee, June. [SRDB Ref ID: 16474]

Auxier, J. A., 1967, “Special Methods in Radiation Dosimetry,” pp. 215–241, Principles of Radiation 

Protection, K. Z. Morgan and J. E. Turner, editors, John Wiley & Sons, New York, New York.

Ballenger, H. F., editor, 1952, Y-12 Plant Health Physics Progress Report, July 1, 1951 to December 

31, 1951, Y-858, Union Carbide Nuclear Company, Y-12 Plant, Oak Ridge, Tennessee, March 

15. [SRDB Ref ID: 13055]

BWXT Y-12, 2000, Recycled Uranium Mass Balance Project Y-12 National Security Complex Site 

Report, Y/LB-16,036, Rev. 1, Y-12 National Security Complex, Oak Ridge, Tennessee, 

December. [SRDB Ref ID: 16500]

Craft, H. R., J. C. Ledbetter, and J. C. Hart, 1953, Personnel Monitoring Operating Techniques, 

ORNL-1411, Carbide and Carbon Chemicals Company, Oak Ridge National Laboratory, Oak 

Ridge, Tennessee, January 21. [SRDB Ref ID: 8576]

DOE (U.S. Department of Energy), 2004, Guide of Good Practices for Occupational Radiological 

Protection at Uranium Facilities, DOE-STD-1136-2004, Washington, D.C., December. [SRDB 

Ref ID: 18881]

Dupree, E. A., J. P. Watkins, J. N. Ingle, P. W. Wallace, C. M. West, and W. G. Tankersley, 1994, 

“Uranium Dust Exposure and Lung Cancer Risk in Four Uranium Processing Operations,” 

Epidemiology, volume 6, number 4, pp. 370–375. [SRDB Ref ID: 79538]

Emlet, L. B., 1952, “Contamination Control: Appendix A – Health Physics Aspects,” letter to R. C. 

Armstrong (U.S. Atomic Energy Commission, Oak Ridge Operations), Carbide and Carbon 

Chemicals Company, Oak Ridge, Tennessee, July 21. [SRDB Ref ID: 20122]

Handloser, J. S., 1959, Health Physics Instrumentation, Pergamon Press, New York, New York.

Hart, J. C., 1966, A Progress Report Dealing with the Derivation of Dose Data from ORNL Personnel 

Exposure Records Applicable to the Mancuso Study, ORNL-CF-66-1-84, Oak Ridge National 

Laboratory, Oak Ridge, Tennessee, January 14. [SRDB Ref ID: 862]

Henderson, M. D., 1991, Evaluation of Radiation Exposure in Metal Preparation Depleted Uranium 

Process Areas, Y/DQ-5/R1, Martin Marietta Energy Systems, Y-12 Plant, Oak Ridge, 

Tennessee, May. [SRDB Ref ID: 8538]

McLendon, J. D., 1957, “Cumulative External Radiation Exposures,” memorandum to J. S. Reece et 

al., Union Carbide Nuclear Company, Oak Ridge, Tennessee, July 1. [SRDB Ref ID: 23622]

McLendon, J. D., 1958 , “Change in Y-12 Film Badge Program,” memorandum to E. W. Bailey et al., 

Union Carbide Nuclear Company, Oak Ridge, Tennessee, March 31. [SRDB Ref ID: 20093]

McLendon, J. D., 1960, “Personnel Radiation Exposure Data,” memorandum to G. W. Flack, Union 

Carbide Nuclear Company, Y-12 Plant, Oak Ridge, Tennessee, August 25. [SRDB Ref ID: 

3694]
Document No. ORAUT-OTIB-0064 Revision No. 02 Effective Date: 04/29/2013 Page 20 of 35

McLendon, J. D., R. G. Affel, A. G. Bailey, K. A. Davis, and E. D. Gupton, 1980, External Radiation 

Monitoring of Union Carbide Nuclear Division Personnel, Y/DD-268, Union Carbide 

Corporation, Y-12 Plant, Oak Ridge, Tennessee, March 23. [SRDB Ref ID: 8589]

Morgan, K. Z., 1961, “Dosimetry Requirements for Protection from Ionizing Radiation,” Selected 

Topics in Radiation Dosimetry, Proceedings of the Symposium on Selected Topics in 

Radiation Dosimetry, Sponsored by and Held in Vienna 7-11 June 1960, International Atomic 

Energy Agency, Vienna, Austria, pp. 3–23. [SRDB Ref ID: 8345]

Murray, R., 1947, Y-12 Plant Health Physics Progress Report, September 1-30, 1947, Y-40, Union 

Carbide and Carbon Chemicals Corporation, Y-12 Plant, Oak Ridge, Tennessee, October 16. 

[SRDB Ref ID: 8602, p. 495]

Murray, R., 1948, Health Physics Progress Report, January 1-31, 1948, Y-120, Carbide and Carbon 

Chemicals Company, Y-12 Plant, Oak Ridge, Tennessee, February 16. [SRDB Ref ID: 8602, 

p. 476]

NBS (National Bureau of Standards), 1962, Physical Aspects of Irradiation, Recommendations of the 

International Commission on Radiological Units and Measurements, Handbook 85, U.S. 

Government Printing Office, Washington, D.C.

NIOSH (National Institute for Occupational Safety and Health), 2007, External Dose Reconstruction 

Implementation Guideline, OCAS-IG-001, Rev. 3, Office of Compensation Analysis and 

Support, Cincinnati, Ohio, November 21.

ORAUT (Oak Ridge Associated Universities Team), 2005, Interpretation of Dosimetry Data for 

Assignment of Shallow Dose, ORAUT-OTIB-0017, Rev. 01, Oak Ridge, Tennessee, October 

11.

ORAUT (Oak Ridge Associated Universities Team), 2006, Occupational Onsite Ambient Dose 

Reconstruction for DOE Sites, ORAUT-PROC-0060, Rev. 01, Oak Ridge, Tennessee, June 

28.

ORAUT (Oak Ridge Associated Universities Team), 2007, Historical Evaluation of the Film Badge 

Program at the Y-12 Plant in Oak Ridge, Tennessee: Part 3 – Beta Radiation, ORAUT-OTIB0046, Rev. 00, Oak Ridge Associated Universities, Oak Ridge, Tennessee, June 22.

ORAUT (Oak Ridge Associated Universities Team), 2009a, Y-12 National Security Complex –

Occupational External Dosimetry, ORAUT-TBKS-0014-6, Rev. 02, Oak Ridge, Tennessee, 

December 18.

ORAUT (Oak Ridge Associated Universities Team), 2009b, Historical Evaluation of the Film Badge 

Program at the Y-12 Plant in Oak Ridge, Tennessee: Part 2 – Neutron Radiation, ORAUTOTIB-0045, Rev. 01, Oak Ridge Associated Universities, Oak Ridge, Tennessee, 

November 30.

ORAUT (Oak Ridge Associated Universities Team), 2011a, Use of Coworker Dosimetry Data for 

External Dose Assignment, ORAUT-OTIB-0020, Rev. 03, Oak Ridge, Tennessee, November 

14.

ORAUT (Oak Ridge Associated Universities Team), 2011b, Parameters to Consider When 

Processing Claims for Construction Trade Workers, ORAUT-OTIB-0052, Rev. 01, Oak Ridge, 

Tennessee, February 17.
Document No. ORAUT-OTIB-0064 Revision No. 02 Effective Date: 04/29/2013 Page 21 of 35

ORAUT (Oak Ridge Associated Universities Team), 2013, Historical Evaluation of the Film Badge 

Dosimetry Program at the Y-12 Facility in Oak Ridge, Tennessee: Part 1 – Gamma Radiation, 

ORAUT-OTIB-0044, Rev. 01, Oak Ridge, Tennessee, April 29.

Ostrouchov, G., E. L. Frome, and G. D. Kerr, 2000, Dose Estimation from Daily and Weekly 

Dosimetry Data, ORNL/TM-1999/282, UT-Battelle, Oak Ridge National Laboratory, Oak Ridge, 

Tennessee, May. [SRDB Ref ID: 24174]

Parrish, B. R., 1979, Analysis of External Personnel Monitoring Devices and Data for Oak Ridge 

Epidemiological Study, Master’s Thesis, School of Public Health, University of North Carolina, 

Chapel Hill, North Carolina. [SRDB Ref ID: 8579]

Patterson, C. M. Jr., C. M. West, and J. D. McLendon, 1957, The Y-12 Health Physics Program, Y1186 Deleted Revision, Union Carbide Nuclear Company, Y-12 Plant, Oak Ridge, Tennessee, 

December 27. [SRDB Ref ID: 14022]

Pearson, K., 1896, “Mathematical Contributions to the Theory of Evolution; III. Regression, Heredity 

and Panmixia,” Philosophical Transactions of the Royal Society of London, Series A, 

Containing Papers of a Mathematical or Physical Character, volume 187, pp. 253–318.

Price, W. J., 1958, Nuclear Radiation Detection, McGraw-Hill Book Company, New York, New York.

Reavis, J. P., 1958, “Frequency of Film Badge Analysis,” memorandum to C. M. West, Union Carbide 

Nuclear Company, Oak Ridge, Tennessee, October 8. [SRDB Ref ID: 20094]

Souleyrette, M. L., 2003, Y-12 National Security Complex, Summary of Historical Monitoring 

Techniques Provided to NIOSH for EEOICPA Data Requests, Rev. 0, BWXT Y-12, Y-12 

National Security Complex, Oak Ridge, Tennessee, February 18. [SRDB Ref ID: 8586]

Spearman, C. E., 1904, “General Intelligence, Objectively Determined and Measured,” American 

Journal of Psychology, volume 15, number 2, pp. 201–293.

Struxness, E. G., 1948a, Health Physics - Industrial Hygiene Progress Report, May 1, - 31, 1948, Y181/1R, Carbide and Carbon Chemicals Corporation, Y-12 Plant, Oak Ridge, Tennessee, 

June 16. [SRDB Ref ID: 8602, p. 456]

Struxness, E. G., 1948b, Health Physics - Industrial Hygiene Progress Report, September 1 - 30, 

1948, Y-259, Carbide and Carbon Chemicals Corporation, Y-12 Plant, Oak Ridge, Tennessee, 

October 8. [SRDB Ref ID: 8602, p. 400]

Struxness, E. G., 1948c, Health Physics - Industrial Hygiene Progress Report, November 1 - 30, 

1948, Y-300/1R, Carbide and Carbon Chemicals Corporation, Y-12 Plant, Oak Ridge, 

Tennessee, December 15. [SRDB Ref ID: 8602, p. 376]

Struxness, E. G., 1949, Health Physics - Industrial Hygiene Progress Report, December 1 - 31, 1948, 

Y-318/1R, Carbide and Carbon Chemicals Corporation, Y-12 Plant, Oak Ridge, Tennessee, 

January 11. [SRDB Ref ID: 8602 p. 364]

Tankersley, W. G., 1982, “Pre-1950 Y-12 Radiation Records,” memorandum to S. A. Fry, Oak Ridge 

Associated Universities, Oak Ridge, Tennessee, July 22. [SRDB Ref ID: 24019]
Document No. ORAUT-OTIB-0064 Revision No. 02 Effective Date: 04/29/2013 Page 22 of 35

Thornton, W. T., D. M. Davis, and E. D. Gupton, 1961, The ORNL Badge Dosimeter and Its Personnel 

Monitoring Applications, ORNL-3126, Union Carbide Corporation, Oak Ridge National 

Laboratory, Oak Ridge, Tennessee. [SRDB Ref ID: 8573]

UCNC (Union Carbide Nuclear Company), 1957, “December Health Physics Report – Mechanics 

Operation Division,” Y-B94-8 (Excerpt), letter to J. M. Case, Oak Ridge, Tennessee, January 

24. [SRDB Ref ID: 23626]

UCNC (Union Carbide Nuclear Company), 1963a, Y-12 Plant Quarterly Health Physics Report, Fourth 

Quarter CY 1962, Y-KB-26, Y-12 Plant, Oak Ridge, Tennessee, March 20. [SRDB Ref ID: 

23618]

UCNC (Union Carbide Nuclear Company), 1963b, Y-12 Plant Quarterly Health Physics Report, Third 

Quarter CY 1962, Y-KB-24, Y-12 Plant, Oak Ridge, Tennessee, February 7. [SRDB Ref ID: 

23167]

Watkins, J. P., J. L. Reagan, D. L. Cragle, E. L. Frome, C. M. West, D .J. Crawford-Brown, and W. G. 

Tankersley, 1993, Data Collection, Validation, and Description for the Oak Ridge Nuclear 

Facilities Mortality Study, ORISE 93/J-42, Oak Ridge Institute for Science and Education, Oak 

Ridge, Tennessee, October. [SRDB Ref ID: 10133]

Watkins, J. P., D. L. Cragle, E. L. Frome, J. L. Reagan, C. M. West, D. J. Crawford-Brown, and W. G. 

Tankersley, 1997, “Collection, Validation, and Treatment of Data for a Mortality Study of 

Nuclear Industry Workers,” Applied Occupational and Environmental Hygiene, volume 12, 

number 3, pp. 195–205. [SRDB Ref ID: 91045]

West, C. M., 1980, “Names of Persons Having Dosimetry Information in the 1947-1950 Period in the 

Y-12 Record Center,” memorandum to H. B. McBride, Jr., Union Carbide Corporation, Oak 

Ridge Gaseous Diffusion Plant, Oak Ridge, Tennessee, October 16. [SRDB Ref ID: 24018]

West, H. [C. M.], 1993, “Brief History of the Y-12 External Monitoring Program,” memorandum to D. 

Cragle, Oak Ridge Institute for Science and Education, Oak Ridge, Tennessee, June 7. 

[SRDB Ref ID: 8532]

Whyte, G. N., 1959, Principles of Radiation Dosimetry, John Wiley & Sons, New York, New York.

Wilcox, W. J. Jr., 2001, An Overview of the History of Y-12, 1942 - 1992, American Museum of 

Science and Energy, Oak Ridge, Tennessee, August. [SRDB Ref ID: 9609]

Williams, W. J., 1948, “Fabrication of Weapon Components,” memorandum to J. C. Franklin, U.S. 

Atomic Energy Commission, Oak Ridge Directed Operations, Washington, D.C., January 15. 

[SRDB Ref ID: 46691]

Wilson, R. H., J. J. Fix, W. V. Baumgartner, and L. L. Nichols, 1990, Description and Evaluation of the 

Hanford Personnel Dosimeter Program from 1944 to 1989, PNL-7447, Battelle Memorial 

Institute, Pacific Northwest Laboratory, Richland, Washington, September. [SRDB Ref ID: 

4793]
Document No. ORAUT-OTIB-0064 Revision No. 02 Effective Date: 04/29/2013 Page 23 of 35

SECTION TITLE PAGE

A.1 Purpose.....................................................................................................................................24

A.2 Background...............................................................................................................................24

A.3 External Radiation Monitoring Devices .....................................................................................25

A.3.1 Pocket Ionization Chambers .........................................................................................25

A.3.2 Film Badge Dosimeters.................................................................................................25

A.4 Y-12 External Dose Database ..................................................................................................26

A.5 Evaluation of 1948–1949 External Dose Data..........................................................................27

A.6 Comparison with Regression Approach Estimates for 1948–1949 Quarterly Doses................32

A.7 Discussion.................................................................................................................................34

TABLE TITLE PAGE

A-1 Number of total and non-NR weekly records by month from Y-12 external monitoring 

file for 1948 and 1949 ...............................................................................................................27

A-2 Number of pocket ionization chamber weekly records from Y-12 monthly external 

monitoring file for 1948 and 1949 and number of these records equal to zero.........................28

A-3 Number of sensitive film–open window (R2) weekly records from Y-12 monthly external 

monitoring file for 1948 and 1949 and number of these records equal to zero and to 30 

mrem.........................................................................................................................................28

A-4 Number of sensitive film–cadmium shielded weekly records from Y-12 monthly external 

monitoring file for 1948 and 1949 and number of these records equal to zero and to 30

mrem.........................................................................................................................................29

A-5 Number of insensitive film–cadmium shielded weekly records from Y-12 monthly 

external monitoring file for 1948 and 1949 and number of these records equal to zero 

and to 30 mrem.........................................................................................................................29

A-6 Means of weekly recorded doses in the quarter from Y-12 external monitoring file, 1948 

and 1949...................................................................................................................................33

A-7 Comparison of mean weekly doses from Table 6-1 scaled up to a full quarter and mean 

quarterly dose estimates from regression approach.................................................................33

A-8 Comparison of mean weekly doses from Table 6-1 with an adjustment for doses 

assigned when below MDL and mean quarterly dose estimates from regression 

approach...................................................................................................................................34

ATTACHMENT A

EXTERNAL RADIATION MONITORING AT THE Y-12 FACILITY DURING THE 1948–1949 PERIOD

Page 1 of 13
Document No. ORAUT-OTIB-0064 Revision No. 02 Effective Date: 04/29/2013 Page 24 of 35

FIGURE TITLE PAGE

A-1 Sums of Y-12 weekly recorded doses by month and year for 1948 and 1949 .........................30

A-2 Statistics for Y-12 weekly R1 doses by month and year...........................................................30

A-3 Statistics for Y-12 weekly R2 doses by month and year...........................................................31

A-4 Statistics for Y-12 weekly R3 doses by month and year...........................................................31

A-5 Statistics for Y-12 weekly R4 doses by month and year...........................................................32

A.1 PURPOSE

The purpose of this Attachment is to discuss and summarize the 1948–1949 external monitoring data 

that are now available for use in the NIOSH Dose Reconstruction Project for workers at facilities 

operated by the DOE and its predecessor agencies (NIOSH 2007). The 1948–1949 external 

monitoring data were made available to the ORAU Team, along with other data for use in 

epidemiological studies of workers at the Y-12 Plant and other DOE sites in Oak Ridge, Tennessee 

(Watkins et al. 1993, 1997). These 1948–1949 data have been placed on a secure data server at the 

ORAU Cincinnati Operations Center for use in dose reconstructions for workers at the Y-12 facility.

A.2 BACKGROUND

The Y-12 Plant, now the Y-12 National Security Complex, was conceived in the fall of 1942 by 

engineers of the Manhattan Engineer District of the U.S. Army Corps of Engineers, and construction 

of the first building was completed in 1943 (Wilcox 2001; ORAUT 2009b). The Tennessee Eastman 

Corporation (TEC) operated Y-12 from 1943 to May 1947. During this period, operations primarily 

involved the use of the electromagnetic separation process to enrich uranium; the enriched product 

was shipped to Los Alamos National Laboratory (LANL) for use in the construction of nuclear 

weapons. Until the latter part of 1945, Y-12 converted UO3 to UCl4, which was enriched by the 

electromagnetic separation process using two calutron stages (“alpha” and “beta”). In the latter part 

of 1945, Y-12 discontinued the use of the alpha stage and began receiving UF6 from the Oak Ridge 

Gaseous Diffusion Plant, also called the K-25 Plant. The UF6 from K-25 was converted into UCl4, 

enriched using the beta calutrons, converted to UF4, and shipped to LANL. In these early days, TEC 

relied entirely on facility monitoring to measure and control occupational external and internal 

radiation exposures to workers. The nature of the work at the Y-12 facility in these early years 

primarily resulted in occupational internal exposure from uranium dust particles, which was a greater 

potential hazard than occupational external exposure (Dupree et al. 1994).

In May 1947, management of Y-12 was assigned to the Union Carbide Corporation (UCC) and the 

emphasis at Y-12 was directed from the enrichment of uranium to the fabrication of parts for nuclear 

weapons (Williams 1948; ORAUT 2009b). Numerous changes have occurred over the years in the 

fabrication procedures, but the general procedures have remained essentially the same. Enriched 

uranium (EU) typically was received at Y-12 in the form of UF6, converted to UF4, reduced to a metal, 

and fabricated into weapon parts. These fabrication processes involved casting, rolling, forming, and 

machining the EU metal and recycling the EU salvage. In addition to facility monitoring to measure 

and control radiation exposure to workers, an external dosimetry program was started in 1948 to 

monitor individual personnel working in the Assay Laboratories, Radiographic Shop, Spectrographic 

Shop, and the “Metal” Machine Shops. Other groups of workers were added in July 1948, January 

1949, and July 1949. The occupational external monitoring since 1950 has been reviewed in ORAUT 

(2009b) and other ORAUT reports (ORAUT 2007, 2013).

ATTACHMENT A

EXTERNAL RADIATION MONITORING AT THE Y-12 FACILITY DURING THE 1948–1949 PERIOD

Page 2 of 13
Document No. ORAUT-OTIB-0064 Revision No. 02 Effective Date: 04/29/2013 Page 25 of 35

A.3 EXTERNAL RADIATION MONITORING DEVICES

Doses to the whole body from external radiation exposure at the Y-12 facility during 1948 and 1949 

were measured using Victoreen pocket ionization chambers (PICs) exchanged on a daily basis and 

film badge dosimeters exchanged on a weekly basis (Souleyrette 2003; ORAUT 2009b). The MDLs 

for these dose measurements during this period were approximately 5 mrem for the PICs and 30 

mrem for the sensitive film of the film badge dosimeters.

A.3.1 Pocket Ionization Chambers

The Victoreen PICs were condenser-type ionization chambers that were used with a separate charger 

and charge reader (Price 1958; Handloser 1959). The PICs were charged to a known voltage by 

inserting them into the charger, which connected an internal power supply across the chambers. The 

charge reader, a string electrometer, indicated the charge. The PICs were the size of fountain pens 

and had clips similar to those on fountain pens so they could be carried securely in the pocket of a 

shirt or coverall. Exposure to ionizing radiation discharged the chamber, and the decrease in voltage 

provided a measurement of a worker’s radiation exposure. The PICs were calibrated using integrated 

exposures of 100, 200, and 300 mR from a radium source (Struxness 1948a).

Properly operating PICs were not bothered by charge leakage over a period of a few days, but their 

use was generally restricted to 1 day (Price 1958; Handloser 1959). At Y-12 and most other DOE 

sites, it was general practice to provide each worker with two PICs, and the lower exposure reading 

was the significant reading because a malfunction of a PIC resulted in a charge decrease, indicating a 

higher exposure. Malfunctions of PICs were usually due to either charge leakage across the 

insulators or mechanical shock such as being dropped on the floor.

The energy response of the PICs, like film, was not flat but peaked at low X-ray energies (Price 1958; 

Handloser 1959). At photon energies of approximately 0.3 to 1.2 MeV, the energy response was 

linear, but it was about 1.4 times the linear response at an energy of approximately 0.1 MeV. Below 

0.1 MeV, the response dropped rapidly because the photons underwent significant attenuation in the 

walls of the PICs. The readings were much less than the actual doses at energies below about 

40 keV. The walls of the PICs were thin enough to allow some response to beta particles with 

energies of approximately 1 MeV or more.

A.3.2 Film Badge Dosimeters

The film badge dosimeter used at Y-12 was the same badge used at the Oak Ridge National 

Laboratory in 1949 (ORAUT 2009b) and described by Thornton, Davis, and Gupton (1961). This was 

a U.S. Atomic Energy Commission Catalog Number PF-1B film badge manufactured by the A. M. 

Sample Machine Company in Knoxville, Tennessee (Patterson et al. 1957; ORAUT 2009b). The 

photographic film in the badge was encased in a protective cover of stainless steel with a clip for 

attachment to the pocket or collar of a shirt or coverall (Handloser 1959). One portion of the film 

(shielded window) was covered by a 1-mm-thick cadmium filter to determine the penetrating wholebody dose from photons (gamma rays and high-energy X-rays); the uncovered portion of the film 

(open window) was used to determine the skin dose from low-energy X-rays and beta particles 

(Handloser 1959).

The film badge dosimeters used at Y-12 from 1948 to 1963 contained DuPont type 552 film packets 

(Souleyrette 2003). These packets contained two film emulsions: (1) a so-called sensitive 502 

ATTACHMENT A

EXTERNAL RADIATION MONITORING AT THE Y-12 FACILITY DURING THE 1948–1949 PERIOD

Page 3 of 13
Document No. ORAUT-OTIB-0064 Revision No. 02 Effective Date: 04/29/2013 Page 26 of 35

emulsion with an effective dose range of approximately 30 mrem to 10 rem, and (2) a so-called 

insensitive 510 emulsion with an effective dose range of approximately 500 mrem to 20 rem (Craft, 

Ledbetter, and Hart 1953; Thornton, Davis, and Gupton 1961; Parrish 1979). Film badge dosimeters 

typically exhibited about the same sensitivity to beta and gamma radiation; that is, a 1-rem dose of 

beta particles yielded about the same response in the film as 1 rem of gamma rays (Auxier 1967). 

Thus, the MDLs of the film badge dosimeters were approximately the same for beta particles and 

gamma rays (ORAUT 2009b).

The DuPont 552 film packets were calibrated using X-rays, beta particles from a natural uranium slab, 

and gamma rays from a radium source (Struxness 1949). The gamma-ray calibrations used 

integrated exposures of 100, 250, 500, 750, and 1,000 mrem from the radium source (Struxness 

1948a). The film badges were calibrated for beta particles by placing the film badge face down on the 

slab of natural uranium (Struxness 1949). The dose rate to skin from the beta particles at the surface 

of the natural uranium slab was taken to be 270 mR/hr (Murray 1948). The currently accepted value 

for the dose rate to skin from beta particles at the surface of a natural uranium slab is approximately 

235 mrem/hr (DOE 2004). If one makes the common assumption that 1 mR/hr is approximately equal 

to 1 mrem/hr (Whyte 1959; NBS 1962), the beta-particle calibrations during the 1948–1949 period 

provide conservative estimates of a Y-12 worker’s exposure to beta particles during that period.

A.4 Y-12 EXTERNAL DOSE DATABASE

External monitoring records for 1950 to 1988 were provided by the Y-12 staff from 1978 through the 

early 1990s for use in epidemiologic studies by the Center for Epidemiologic Research of the Oak 

Ridge Associated Universities (Watkins et al. 1993, 1997). These records contained gamma, beta, 

and neutron monitoring records for individuals, summarized by quarters. For some time, it was 

assumed that no external monitoring records were available before 1950. After considerable 

investigation, including interviews with knowledgeable Y-12 staff members, it was discovered that a 

limited set of external monitoring data did exist for 1948 and 1949 (West 1980). Further investigation 

resulted in the retrieval of a single electronic file with 11,492 weekly monitoring records. Each record 

in the file included film badge identification (ID), date of weekly readings, four dose fields, and 

descriptive comments. The four dose fields consisted of the PIC dose reading and three photographic 

film dose readings. The PIC doses were the sum of the daily readings for the week and are referred 

to as R1. Doses from film badge readings of sensitive film with open window, sensitive film with 

shielding, and insensitive film with shielding are referred to as R2, R3, and R4, respectively.

Efforts were made to link the film badge ID in the Y-12 external monitoring file for 1948 and 1949 with 

Y-12 worker names and departments in the ORAU Team DOE facility database. A total of 229 

distinct individuals were identified among the 11,492 records in the dataset. Each film badge ID in the 

Y-12 external monitoring file for 1948 and 1949 had 26, 52, 78, or 104 records, corroborating that 

monitoring results were recorded on a weekly basis during this period. As listed in Table A-1, there 

were 3,599 and 7,893 weekly records for 1948 and 1949, respectively. Based on four weekly 

monitoring records during some months and five weekly monitoring records during other months, the 

data in Table A-1 indicate that the total number of monitored Y-12 workers was approximately 26 

during the first half of 1948, 107 during the second half of 1948, 141 during the first half of 1949, and 

168 during the second half of 1949.

Although each record in the dataset had a value for all four dose fields (R1, R2, R3, and R4), many of 

the results were recorded as NR (no reading or no response). In fact, 7,876 or 69% of the 11,492 

total records reported NR in each of the four dose fields. Therefore, only 3,616 of the records 

ATTACHMENT A

EXTERNAL RADIATION MONITORING AT THE Y-12 FACILITY DURING THE 1948–1949 PERIOD

Page 4 of 13
Document No. ORAUT-OTIB-0064 Revision No. 02 Effective Date: 04/29/2013 Page 27 of 35

Table A-1. Number of total and non-NR weekly 

records by month from Y-12 external monitoring file 

for 1948 and 1949.

Month

1948

Total records/

non-NR recordsa

1949

Total records/

non-NR recordsa

January 130/0 564/165

February 104/0 564/150

March 104/0 564/162

April 130/41 705/186

May 104/77 564/148

June 104/60 564/186

July 535/162 840/272

August 428/146 672/255

September 428/144 840/271

October 535/201 672/203

November 428/164 672/200

December 569/208 672/215

Total 3,599/1,203 7,893/2,413

a. At least one of the R1, R2, R3, or R4 values in the record 

was not NR (i.e., at least one of the R1, R2, R3, or R4 

contained a number that represented a dose).

supplied information on occupational external doses. The information provided by these 3,616 

records is summarized in the next section.

A.5 EVALUATION OF 1948–1949 EXTERNAL DOSE DATA

Results in this section are based on all weekly records occurring in a month, although an individual 

worker could have provided multiple weekly records each month. Tables A-2 to A-5 present by month 

and year the number of non-null records and the number of these records equal to zero for R1, R2, 

R3, and R4, respectively. In addition, the number of these records with a dose of 30 mrem is listed for 

R2, R3, and R4. From January through March 1948, all dose field readings were blank. During the 

second half of 1948 and all of 1949, nearly all recorded doses for R2, R3, and R4 were set to 

30 mrem. In 1949, R3 and R4 were generally not recorded because there were only 60 and 61 

recorded doses, respectively, compared with 1,744 R2 doses, 99.5% of which equaled 30 mrem. 

Therefore, R2, R3, and R4 provided very few specific radiation doses, and 30 mrem was used as an 

upper bound on the actual dose received during the weekly monitoring period for film badges.

Figure A-1 shows the sum of all weekly records by month for R1 to R4. In 1948, the monthly dose 

sums were nearly identical for R2, R3, and R4, with the exception of a slightly lower R4 dose in July. 

The monthly sums for the PIC readings starting in July 1948 were generally about one-third as large 

as film badge sums for R2, R3, and R4. In 1949, the monthly PIC sums were about one-third or less 

of the R2 sums, with the exception of the period from March through June, when the R2 sums dipped 

much lower. Sums for R3 and R4 in 1949 were at or near zero except for January.

Figures A-2 to A-5 show descriptive statistics by month and year for R1 to R4, respectively, based on 

all weekly recorded doses excluding the NRs. The 75th percentile for R1 was near 30 mrem for the 

entire period from April 1948 through December 1949, indicating that approximately three-fourths of 

the PIC weekly readings each month had a value of 30 mrem or less. However, maximum R1 

ATTACHMENT A

EXTERNAL RADIATION MONITORING AT THE Y-12 FACILITY DURING THE 1948–1949 PERIOD

Page 5 of 13
Document No. ORAUT-OTIB-0064 Revision No. 02 Effective Date: 04/29/2013 Page 28 of 35

Table A-2. Number of PIC (R1) weekly records from Y-12 

monthly external monitoring file for 1948 and 1949 and number 

of these records equal to zero.

Month

1948 1949

N N = 0 N N = 0

January 0 127 35

February 0 123 23

March 0 119 23

April 3 1 138 14

May 54 23 97 9

June 46 11 94 14

July 115 33 104 19

August 111 27 97 25

September 118 43 118 30

October 147 44 86 23

November 111 42 80 20

December 136 50 81 27

Total R1 841 274 (32.6%) 1,264 262 (20.7%)

Table A-3. Number of sensitive film–open window (R2) weekly records from Y-12 monthly external 

monitoring file for 1948 and 1949 and number of these records equal to zero and to 30 mrem.

Month

1948 1949

N N = 0 N = 30 N N = 0 N = 30

January 0 98 0 94

February 0 93 0 90

March 0 100 0 99

April 40 14 0 102 0 102

May 76 29 0 101 0 101

June 60 7 5 139 0 139

July 142 0 124 232 0 232

August 140 0 140 196 0 196

September 137 0 136 200 0 200

October 200 0 200 158 0 158

November 161 0 161 156 0 156

December 200 0 200 169 0 169

Total R2 1,156 50 (4.3%) 966 (83.6%) 1,744 0 (0%) 1,736 (99.5%)

readings were generally above 60 mrem after October 1948. Beginning in July 1948, the R2 values of 

the 25th percentile, median, and 75th percentile were all 30 mrem, suggesting that a dose of 30 mrem 

was likely to be assigned if a weekly badge reading during the month fell below the MDL. For R3 from 

July 1948 through March 1949, it appears that a dose of 30 mrem was assigned if a weekly badge 

reading was below the MDL, and beginning in April 1949 the weekly badge reading was listed as NR 

if the reading was below the MDL. For R4 it appears that 30 mrem was assigned based on the MDL 

of R2 and R3 during the same period. Several very high maximum doses were recorded for R2, 

including 760 mrem in July 1948 and 2,500 mrem in both January and February 1949 (see 

Figure A-3). With the exception of one R3 dose of 640 mrem in July 1948, R3 and R4 have weekly 

doses of only 30 mrem from July 1948 through March 1949 and then no additional dose records 

except one R4 dose of 30 mrem in November (see Figures A-4 and A-5). Figure A-5 shows that 

30 mrem was the maximum recorded dose for R4 throughout 1948 and 1949.

ATTACHMENT A

EXTERNAL RADIATION MONITORING AT THE Y-12 FACILITY DURING THE 1948–1949 PERIOD

Page 6 of 13
Document No. ORAUT-OTIB-0064 Revision No. 02 Effective Date: 04/29/2013 Page 29 of 35

Table A-4. Number of sensitive film–cadmium shielded (R3) weekly records 

from Y-12 monthly external monitoring file for 1948 and 1949 and number of 

these records equal to zero and to 30 mrem.

Month

1948 1949

N N = 0 N = 30 N N = 0 N = 30

January 0 56 0 56

February 0 3 0 3

March 0 1 0 1

April 40 14 0 0

May 76 29 0 0

June 60 7 5 0

July 142 0 124 0

August 140 0 140 0

September 137 0 137 0

October 200 0 200 0

November 161 0 161 0

December 200 0 200 0

Total R3 1,156 50 (4.3%) 966 (83.6%) 60 0 (0%) 60 (100%)

Table A-5. Number of insensitive film–cadmium shielded (R4) weekly records 

from Y-12 monthly external monitoring file for 1948 and 1949 and number of 

these records equal to zero and to 30 mrem.

Month

1948 1949

N N = 0 N = 30 N N = 0 N = 30

January 0 0 0 56 0 56

February 0 0 0 3 0 3

March 0 0 0 1 0 1

April 40 19 0 0

May 76 35 0 0

June 60 8 0 0

July 142 0 142 0

August 139 0 139 0

September 143 0 143 0

October 200 0 200 0

November 161 0 161 1 1

December 200 0 200 0

Total R4 1,161 62 (5.3%) 985 (84.8%) 61 0 (0%) 61 (100%)

The two very high weekly R2 doses in Figure A-3 in January and February 1949, which occurred in 

one worker, suggest a large skin dose that might not have been detected by the PICs. These two 

high R2 doses do not appear to be due to beta particles because the ratio of R2 to R3 of 

approximately 100:1 is much larger than the expected beta-to-gamma dose ratio from exposure to 

uranium. These two high readings are more likely the result of exposure to very-low-energy photons 

leaking from an X-ray spectrograph or other devices, a problem that was noted in early Health 

Physics reports (Struxness 1948b,c). The R2 readings from the 502 sensitive film under the open 

window of a film badge show a response to photons with energies less than 0.1 MeV that is as much 

as 15 to 20 times greater than the response to photons of higher energies (Handloser 1959; Thornton, 

Davis, and Gupton 1961). However, PICs have trouble detecting photons with energies less than 

0.1 MeV because they are heavily attenuated in the wall materials of the PICs, as discussed in 

ATTACHMENT A

EXTERNAL RADIATION MONITORING AT THE Y-12 FACILITY DURING THE 1948–1949 PERIOD

Page 7 of 13
Document No. ORAUT-OTIB-0064 Revision No. 02 Effective Date: 04/29/2013 Page 30 of 35

1 2 3 4 5 6 7 8 9 10 11 12

Month

0

2000

4000

6000

8000

0

2000

4000

6000

8000

1949

1948

 

R1

R2

R3

R4

Figure A-1. Sums of Y-12 weekly recorded doses (mrem) by month and year 

for 1948 and 1949.

1 2 3 4 5 6 7 8 9 10 11 12

Month

0

30

60

90

120

0

30

60

90

120

1949

1948

Maximum

75th percentile

Median

Mean

25th percentile

y ( )

Figure A-2. Statistics for Y-12 weekly R1 doses (mrem) by month and year

(NRs excluded).

ATTACHMENT A

EXTERNAL RADIATION MONITORING AT THE Y-12 FACILITY DURING THE 1948–1949 PERIOD

Page 8 of 13
Document No. ORAUT-OTIB-0064 Revision No. 02 Effective Date: 04/29/2013 Page 31 of 35

1 2 3 4 5 6 7 8 9 10 11 12

Month

0

100

200

300

0

100

200

300

1949

1948

Maximum

75th percentile

Median

Mean

25th percentile

Monthly statistics for R2 doses in mrem (NRs excluded)

Jan. and Feb. 1949 maximums truncated 

from 2500 to 300 for graphing

July 1948 max truncated 

from 760 to 300 for graphing

Figure A-3. Statistics for Y-12 weekly R2 doses (mrem) by month and year

(NRs excluded).

1 2 3 4 5 6 7 8 9 10 11 12

Month

0

30

60

90

0

30

60

90

1949

1948

Maximum

75th percentile

Median

Mean

25th percentile

y ( )

July 1948 maximum truncated 

from 640 to 100 for graphing.

Figure A-4. Statistics for Y-12 weekly R3 doses (mrem) by month and year

(NRs excluded).

ATTACHMENT A

EXTERNAL RADIATION MONITORING AT THE Y-12 FACILITY DURING THE 1948–1949 PERIOD

Page 9 of 13
Document No. ORAUT-OTIB-0064 Revision No. 02 Effective Date: 04/29/2013 Page 32 of 35

1 2 3 4 5 6 7 8 9 10 11 12

Month

0

10

20

30

0

10

20

30

1949

1948

Maximum

75th percentile

Median

Mean

25th percentile

 

Figure A-5. Statistics for Y-12 weekly R4 doses (mrem) by month and year

(NRs excluded).

Section 3.1. The high R2 reading for another worker in July 1948 appears to be an artifact because: 

(1) the R2 and R3 readings for the skin and whole-body doses are nearly equal (see Figures A-3 and 

A-4), and (2) the high R3 reading of 640 mrem for the whole-body dose is not observed in the R1 or 

R4 readings for the worker (see Figures A-2 and A-5).

A.6 COMPARISON WITH REGRESSION APPROACH ESTIMATES FOR 1948–1949 

QUARTERLY DOSES

In this section the means of the weekly R1, R2, R3, and R4 doses from the Y-12 external monitoring 

file for 1948 and 1949 are calculated and then scaled to full quarter values to be compared with 

corresponding mean quarterly doses that were estimated using the regression approach for gamma 

and beta doses discussed in ORAUT (2013) and ORAUT (2007) respectively. The purpose of this 

comparison is to examine whether the regression approach provides realistic estimates that are 

favorable to claimants for dose reconstruction purposes. The mean dose was selected as the most 

appropriate comparison statistic from the regression approach because it is calculated using both the 

log of the geometrical mean μ and the log of the geometrical standard deviation σ. Specifically, for a 

given quarter the mean dose on the original scale (arithmetic mean) from regression is calculated as 

follows:

2 E dose ( ) exp( 0.5 ) = + μ σ (A-1)

The weekly mean doses for R1, R2, R3, and R4 were calculated directly with all NRs deleted before 

calculation to ensure that results were not lowered, and are listed in Table A-6. It is important to note 

that each dose entry in the Y-12 external monitoring file for 1948 and 1949 represents the dose per 

ATTACHMENT A

EXTERNAL RADIATION MONITORING AT THE Y-12 FACILITY DURING THE 1948–1949 PERIOD

Page 10 of 13
Document No. ORAUT-OTIB-0064 Revision No. 02 Effective Date: 04/29/2013 Page 33 of 35

week in the specified quarter and not the dose per quarter. In order to make a valid comparison with 

the regression results, weekly means must be scaled up to represent the dose over an entire quarter. 

Table A-7 lists the average weekly dose from Table A-6 multiplied by 12.5 weeks per quarter, 

assuming 50 working weeks and 2 vacation weeks per year. R3, the sensitive film reading under the 

1-mm-thick cadmium shield of film badge, can be compared to the regression approach quarterly 

gamma dose estimates, E(gamma dose), in the next to last column of the Table A-7. For R2, the 

sensitive film reading under the open window of the film badge, comparison can be made to 

E(beta dose) from the regression approach, which is the last column of the table.

Table A-6. Means of weekly recorded doses in the quarter from 

Y-12 external monitoring file, 1948 and 1949.

Year Quarter

Means of weekly doses in each quarter

E(R1) E(R2) E(R3) E(R4)

1948 1 ----- ---- ---- ----

2 12.03 7.98 7.53 5.65

3 11.09 32.58 31.86 30.00

4 12.20 30.00 30.00 30.00

1949 1 17.29 59.85 30.00 30.00

2 20.12 30.00 ---- ----

3 15.49 30.00 ---- ----

4 13.10 30.00 ---- 30.00

Table A-7. Comparison of mean weekly doses from Table A-6 scaled up to a full 

quarter and mean quarterly dose estimates from regression approach.

Year Quarter

Weekly means scaled to full quarter E(gamma 

dose)a

E(beta 

dose)b E(R1) E(R2) E(R3) E(R4)

1948 1 ----- ---- ---- ---- 362.54 2,272.0

2 150.36 99.75 94.13 70.63 351.66 2,235.7

3 138.63 407.25 398.25 375.00 341.11 2,199.5

4 152.50 375.00 375.00 375.00 330.87 2,163.2

Total 441.49 882.00 867.38 820.63 1,386.18 8,870.4

1949 1 216.13 748.13 375.00 375.00 320.94 2,127.0

2 251.50 375.00 ---- ---- 311.31 2,090.7

3 193.63 375.00 ---- ---- 301.97 2,054.5

4 163.75 375.00 ---- 375.00 292.91 2,018.2

Total 825.01 1873.13 375.00 750.00 1,227.14 8,290.4

a. See Table 7-1a in this document and Table 7-1 in ORAUT (2013) for gamma dose arithmetic 

means from regression approach to E(R3).

b. See ORAUT (2007, Table 9-2) for beta dose arithmetic means from regression approach to 

E(R2).

When the weekly doses are scaled up to a full quarter as listed in Table A-7, most of the 

quarterly means based on the monitoring data for 1948 and 1949 in column E(R3) tend to 

slightly surpass the gamma dose estimates based on the regression approach. However, 

the vast majority of the R3 dose records in the Y-12 external monitoring file for 1948 and 

1949 had a recorded value of 30 mrem (see Table A-4), which was probably assigned to a 

worker when the film badge reading was below the MDL, and represented a bounding dose 

to the worker for that week. In early 1948, a zero was entered instead to indicate a film 

badge reading of less than the MDL (see Table A-4). It is clear that the quarterly regression 

approach estimates are reasonable estimates of the gamma doses received by workers in 

these 2 years. In contrast, the quarterly beta dose comparisons of E(R2) to the regression 

ATTACHMENT A

EXTERNAL RADIATION MONITORING AT THE Y-12 FACILITY DURING THE 1948–1949 PERIOD

Page 11 of 13
Document No. ORAUT-OTIB-0064 Revision No. 02 Effective Date: 04/29/2013 Page 34 of 35

approach reveal that backwards extrapolation of beta doses provides ultraconservative dose 

estimates for workers in 1948 and 1949. The source of this discrepancy for beta doses is 

that in 1948 and 1949 machining at Y-12 mainly involved EU, which was reflected in R2 

doses that differed little from R3 doses. It was not until 1950 that the monitoring program 

was expanded and included workers with exposure to natural and depleted uranium because 

machining process began to involve less highly enriched uranium (ORAUT 2007). The 

regression approach was based on beta doses for 1956 to 1965 when machining processes 

mainly involved natural and depleted uranium. Figure 4-1 of ORAUT (2007) illustrates the 

increasing dose rate of beta particles as the percent of enrichment of uranium declines.

To assess the possible impact of the dose entries listed as “less than the MDL,” the dose records for 

R2, R3, and R4 with values of zero or 30 mrem were changed to half of the MDL or 15 mrem, as 

recommended by NIOSH (2007). Table A-8 lists the recalculated means scaled up to a full quarter. 

There were a few dose entries that had non-zero values that were less than the MDL. It is likely that 

these represent film readings with a detection limit that was deemed more accurate than the typical 

MDL of 30 mrem (Morgan 1961). These values were not adjusted in the analysis in Table A-8, though 

it is clear that adjusting these values by half would further reduce the mean quarterly doses derived 

from the Y-12 external monitoring file for 1948 and 1949.

Table A-8. Comparison of mean weekly doses from Table A-6 with an adjustment 

for doses assigned when below MDL and mean quarterly dose estimates from 

regression approach.

Year Quarter

Y-12 dose files for 1948–1949a E(gamma

dose)b

E(beta 

dose)c E(R1) E(R2) E(R3) E(R4)

1948 1 ----- ---- ---- ---- 362.54 2272.0

2 150.74 147.73 143.11 136.72 351.66 2235.7

3 142.81 228.22 218.38 187.50 341.11 2199.5

4 157.92 187.50 178.50 187.50 330.87 2163.2

Total 457.46 563.45 548.99 511.72 1386.18 8870.4

1949 1 222.98 565.72 187.50 187.50 320.94 2127.0

2 250.00 187.50 ---- ---- 311.31 2090.7

3 196.22 187.50 ---- ---- 301.97 2054.5

4 167.38 187.50 ---- 187.50 292.91 2018.2

Total 836.59 1128.22 187.50 375.00 1227.14 8290.4

a. Doses below MDL, listed as 0 or 30 mrem, were set to 15 mrem (half the R2 and R3 MDL) as 

recommended in NIOSH (2007).

b. See Table 7-1a in this document and Table 7-1 in ORAUT (2013) for gamma dose arithmetic 

mean from regression approach to E(R3).

c. See ORAUT (2007, Table 9-2) for beta dose arithmetic mean from regression approach to 

E(R2).

Table A-8 indicates that when dose entries of 0 or 30 mrem are adjusted to half of the MDL, the 

resulting mean doses in column E(R3) all fall below the comparable quarterly results from the 

regression approach, E(gamma dose). This comparison provides further evidence that the quarterly 

gamma doses from the regression approach are valid estimates of worker dose during this period. 

Quarterly beta doses from the regression approach are again ultraconservative, reflecting the 

difference in sources of beta dose exposure in 1948 and 1949 than in later years.

A.7 DISCUSSION

The Y-12 external monitoring data for 1948 and 1949 have been reviewed in this report and appear to 

be useful in a variety of ways for dose reconstructions of Y-12 workers. In an earlier study, for 

ATTACHMENT A

EXTERNAL RADIATION MONITORING AT THE Y-12 FACILITY DURING THE 1948–1949 PERIOD

Page 12 of 13
Document No. ORAUT-OTIB-0064 Revision No. 02 Effective Date: 04/29/2013 Page 35 of 35

example, gamma-ray dose data for Y-12 workers from 1950 to 1979 were reviewed, and a method 

was developed for estimating gamma-ray dose starting with the UCC management change in the third 

quarter of 1947 (ORAUT 2013). During the 1948–1949 period, PICs and film badge dosimeters were 

used at Y-12 (Souleyrette 2003; ORAUT 2009a), and the PICs appear to provide the doses of record. 

This is consistent with practices at other DOE facilities such as the Oak Ridge National Laboratory 

and Hanford Site (Ostrouchov, Frome, and Kerr 2000). Initially, PICs were considered the primary 

device for monitoring worker exposures, and film badge dosimeters were considered a valuable 

adjunct (Hart 1966). Eventually, the film badge dosimeters were considered as providing the dose of 

record, and the PICs became the day-to-day means of monitoring worker exposures (Wilson et al. 

1990). The switch from PICs to film badge dosimeters to provide the doses of record occurred in 

1950 at Y-12 (ORAUT 2013).

Pre-1950 film badge data have been considered questionable because of frequently changed 

procedures and a perceived general lack of monitoring quality control during this period (Tankersley 

1982). For example, for R2, R3, and R4 in the Y-12 data, it appears that from April through June 

1948, 0 was assigned to below-MDL weekly readings while 30 mrem was assigned to such readings 

for the remainder of 1948 and for 1949 (see Tables A-2 to A-4). In addition, the very large doses 

observed in the R2 and R3 film badge responses were sometimes absent in the PIC data (see 

Figures A-2 to A-4). The PIC data were obtained with devices that were very simple to use; they 

should have provided reliable data about whole-body doses from gamma rays and high-energy beta 

particles during the 1948–1949 period. Several R2 readings suggest high exposures to the skin from 

very low-energy photons that might not have been detected by the PICs (see Figure A-3).

Gamma doses have been the focus of this TIB because of the possible link between these doses and 

most of the cancers relevant to dose reconstruction. This investigation of the Y-12 external 

monitoring data for 1948 and 1949 has clearly demonstrated that backwards extrapolation from the 

regression approach provides a reasonable method that is favorable to claimants for use in the 

reconstruction of potential whole-body doses from photon exposures to workers at the Y-12 facility 

during the late 1940s and early 1950s. Although gamma doses were the major interest, beta doses 

were also investigated. It was found that backwards extrapolation from 1956 to 1965 beta doses to 

the 1948 to 1949 period furnishes ultraconservative doses because of the continuing shift from mainly 

highly enriched uranium before 1950 to principally natural and depleted uranium by 1960.

ATTACHMENT A

EXTERNAL RADIATION MONITORING AT THE Y-12 FACILITY DURING THE 1948–1949 PERIOD

Page 13 of 13