ORAU TEAM

Dose Reconstruction

Project for NIOSH

Oak Ridge Associated Universities I Dade Moeller & Associates I MJW Corporation

Page 1 of 12

Document Title:

External Coworker Dosimetry Data for the Sandia 

National Laboratory in Albuquerque, New Mexico

Document Number: ORAUT-OTIB-0072

Revision: 00

Effective Date: 09/26/2008

Type of Document OTIB

Supersedes: None

Subject Expert(s): Matthew H. Smith, Keith A. McCartney

Site Expert(s): N/A

Approval: Signature on File Approval Date: 08/20/2008

Matthew H. Smith, Document Owner

Concurrence: Richard Merrill Signature on File for Concurrence Date: 07/31/2008

John M. Byrne, Task 3 Manager

Concurrence: Signature on File Concurrence Date: 07/31/2008

Edward F. Maher, Task 5 Manager

Concurrence: Signature on File Concurrence Date: 08/19/2008

Kate Kimpan, Project Director

Approval: Signature on File Approval Date: 09/26/2008

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-0072 Revision No. 00 Effective Date: 09/26/2008 Page 2 of 12

PUBLICATION RECORD

EFFECTIVE 

DATE

REVISION 

NUMBER DESCRIPTION

09/26/2008 00 Approved new technical information bulletin to provide information to 

allow ORAU Team dose reconstructors to assign doses at the 

Sandia National Laboratory in Albuquerque, New Mexico to certain 

workers who have no or limited monitoring data, based on site 

coworker data. No changes occurred as a result of formal internal 

and NIOSH review. Training required: As determined by the Task 

Manager. Initiated by Matthew H. Smith. 

Trademark Information

Microsoft, Access, and Excel are registered trademarks of Microsoft Corporation in the United States 

and/or other countries.
Document No. ORAUT-OTIB-0072 Revision No. 00 Effective Date: 09/26/2008 Page 3 of 12

TABLE OF CONTENTS

SECTION TITLE

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

PAGE

4

1.0 Introduction ..............................................................................................................................5

2.0 Purpose ...................................................................................................................................5

3.0 Background..............................................................................................................................5

4.0 General Approach....................................................................................................................6

5.0 Applications and Limitations.....................................................................................................6

6.0 Coworker Data Development ...................................................................................................6

6.1 Adjustment for Missed Dose.........................................................................................7

6.2 Special Considerations.................................................................................................8

7.0 Coworker Annual Dose Summaries .........................................................................................8

8.0 Attributions and Annotations .................................................................................................. 11

References ........................................................................................................................................12

LIST OF TABLES

TABLE TITLE

6-1 Distribution of SNL SRDB dosimetry records by year...............................................................

PAGE

7

6-2 SNL dosimetry components .....................................................................................................7

6-1 Missed external doses based on ORAUT-TKBS-0037 ............................................................. 8

7-1 Annual SNL external coworker doses modified to account for missed dose ........................... 10

7-2 Annual SNL external coworker doses modified in accordance with 

ORAUT-OTIB-0052................................................................................................................10
Document No. ORAUT-OTIB-0072 Revision No. 00 Effective Date: 09/26/2008 Page 4 of 12

ACRONYMS AND ABBREVIATIONS

DOE U.S. Department of Energy

EEOICPA Energy Employees Occupational Illness Compensation Program Act of 2000

IREP Interactive RadioEpidemiological Program

LOD limit of detection

mrem millirem

NIOSH National Institute for Occupational Safety and Health

ORAU Oak Ridge Associated Universities

SNL Sandia National Laboratories

SRDB Site Research Database

SSN Social Security Number

TIB technical information bulletin

TLD thermoluminescent dosimeter

U.S.C. United States Code

§ section or sections
Document No. ORAUT-OTIB-0072 Revision No. 00 Effective Date: 09/26/2008 Page 5 of 12

1.0

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 

historic 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.

INTRODUCTION

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 [EEOICPA; 42 U.S.C. § 7384l(5) and (12)].

2.0

The purpose of this TIB is to provide information to allow dose reconstructors to assign doses based 

on site coworker data to Sandia National Laboratory in Albuquerque, New Mexico (SNL) workers who 

have no or limited monitoring data. In addition, the data in this TIB should be used to assign dose for 

gaps in the dosimetry record. The data are to be used in conjunction with ORAUT-OTIB-0020, Use of 

Coworker Dosimetry Data for External Dose Assignment (ORAUT 2005).

PURPOSE

3.0

The Oak Ridge Associated Universities (ORAU) Team is conducting a series of coworker data studies 

to permit dose reconstructors to complete certain cases for which external or internal monitoring data 

are unavailable or incomplete. Cases that do not have complete monitoring data could fall into one of 

several categories:

BACKGROUND

• 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.

• The worker might have been monitored, but the data are not available to the dose 

reconstructor.

• Partial information is available, but it is insufficient to facilitate a dose reconstruction.

As described in ORAUT-OTIB-0020 (ORAUT 2005), some cases without complete monitoring data 

can be processed based on assumptions and methodologies that do not involve coworker data. For 

example, many cases in the first category can be processed by the assignment of ambient external 

and internal doses based on information in the relevant site technical basis documents.

As described in ORAUT-TKBS-0037, Site Profile for Sandia National Laboratories (ORAUT 2007a), 

operations at the laboratory (separate from Los Alamos) began in 1949. SNL used a variety of film 

dosimeters between 1949 and 1971. A two-chip thermoluminescent dosimeter (TLD) was used 

starting in 1971 and a multichip TLD was implemented in 1974. Exchange frequencies varied from 

quarterly to biweekly dependent on job duties. There does not appear to have been any significant 

administrative practice that would have jeopardized the integrity of the dose of record.
Document No. ORAUT-OTIB-0072 Revision No. 00 Effective Date: 09/26/2008 Page 6 of 12

4.0

As described in ORAUT-OTIB-0020 (ORAUT 2005), the general approach to the development of 

coworker data for cases without external monitoring data is to assign either 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.

GENERAL APPROACH

5.0

Some SNL 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.

APPLICATIONS AND LIMITATIONS

The data in this TIB address penetrating gamma radiation and nonpenetrating electron and/or lowenergy photon radiation. Neutron data are not presented separately; methods for determining neutron 

dose are discussed in Section 7.0. 

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

6.0

Since an electronic database was not available from SNL, a Microsoft® Access® database that 

contains the raw dosimetry data was created by combining individual Excel® spreadsheets into one 

dataset. The individual Excel® spreadsheets were created by transcribing dosimetry information from 

documents that were captured and recorded in the Site Research Database (SRDB). Hard-copy 

dosimetry records were available for the periods from 1959 to 1986 and from 1992 to 1994. 

COWORKER DATA DEVELOPMENT

The original dataset contained 254,873 records, which was culled to 236,902 records, which reduced 

the total number of records available for analysis by approximately 7% (see yearly distribution of 

records in Table 6-1). Dosimetry records that were removed from the original dataset were 

unremarkable (i.e., excluding these values should not affect the overall results). Records were 

removed from the original dataset for the following reasons:

• Illegible dates;

• Dose reported was cumulative and could not be binned into a single year;

• Dose record was of poor quality and could not be read accurately;

• The badge return date precedes the issue date; or

• The wear period was greater than 400 days. 

An assumption was made that the dose could be assigned to a single year if the wear period (i.e., the 

number of days between the date the badge was issued and the date the badge was returned) was 

less than 400 days.

The annual data for each worker were prorated to account for partial years of employment based on 

an analysis of the length of monitored employment that was associated with the data (see Section 6.2 

for further discussion of special considerations). The data were prorated so coworker doses that 
Document No. ORAUT-OTIB-0072 Revision No. 00 Effective Date: 09/26/2008 Page 7 of 12

Table 6-1. Distribution of SNL SRDB dosimetry records by year.

Year

# of 

Records Year

# of 

Records Year

# of 

Records

1949 1 1965 338 1981 21,199

1950 0 1966 265 1982 22,023

1951 0 1967 465 1983 23,453

1952 0 1968 318 1984 18,963

1953 0 1969 282 1985 21,999

1954 0 1970 496 1986 25,606

1955 0 1971 794 1987 0

1956 0 1972 1,477 1988 0

1957 6 1973 1,879 1989 0

1958 0 1974 1,465 1990 0

1959 72 1975 1,799 1991 4

1960 1,533 1976 2,358 1992 6,183

1961 1,055 1977 20,239 1993 1,514

1962 1,704 1978 20,299 1994 71

1963 1,122 1979 18,217

1964 493 1980 19,210

represent a full year of monitored employment could be derived; this permits the dose reconstructor to 

assign appropriate doses based on specific employment dates and job descriptions. 

The dosimetry components that were developed from the data and available in the Access® database 

are shown in Table 6-2. Gamma was used as the primary value to represent deep dose. In the 

absence of a gamma value, the body dose, minus any neutron dose, was used if available. The 

shallow dose (i.e., open-window dose) was calculated as a precursor for the nonpenenetrating dose 

calculation. The skin dose was used for the shallow dose. In the absence of skin dose, the 

calculated deep dose was added to the nonpenetrating (NPR) dose. This step was necessary 

because some records listed a skin dose while others had only a NPR dose. The nonpenetrating

dose was calculated by subtracting the deep dose from the shallow dose.

Table 6-2. SNL dosimetry components.

Dose 

component Comment

Body Photon penetrating dose + neutron

Skin Penetrating + nonpenetrating dose

Extremity ~9,700 records in the database but extremity dose was not evaluated

Eye Few records in database: ~400 records with 100 mrem or more dose

Gamma Photon penetrating dose

Neutron Few records in database: ~300 records with 100 mrem or more dose

NPR Nonpenetrating dose

6.1 ADJUSTMENT FOR MISSED DOSE

According to OCAS-IG-001, External Dose Reconstruction Implementation Guideline (NIOSH 2007), 

missed doses are assigned for reported zero readings for each monitoring cycle to account for the 

possibility that doses were received but either not recorded by the dosimeter or not reported by the 

site. In addition, reported dose values less than one-half the applicable minimum detection limits are 

assigned as missed dose. Annual maximum potential missed doses are calculated by multiplying the 

number of zero or unrecorded badge readings by the reported dosimeter limit of detection (LOD) and 

summing the results. These values are used as the 95th percentile of a lognormal distribution to 

calculate the probability of causation, which is determined by the U.S. Department of Labor. Thus, in 

the Interactive RadioEpidemiological Program (IREP), Parameter 1 input is equal to the calculated 
Document No. ORAUT-OTIB-0072 Revision No. 00 Effective Date: 09/26/2008 Page 8 of 12

maximum annual missed doses multiplied by 0.5, and the Parameter 2 input is equal to 1.52. These 

values represent the geometric mean and geometric standard deviation, respectively, for each year of 

analysis.

The assignment of maximum potential missed doses for monitored workers is particularly significant 

for SNL workers from 1949 to 1971, when they could have been monitored biweekly. Table 6-3 lists 

the maximum annual missed dose by monitoring period based on information in ORAUT-TKBS-0037 

(ORAUT 2007a).

Table 6-3. Missed external doses (rem) based on ORAUT-TKBS-0037 (ORAUT 2007a).

Monitoring 

period

Penetrating 

LOD

(rem)

Nonpenetrating 

LOD

(rem)

Exchange 

frequencya

Maximum 

potential annual 

missed 

penetrating dose

(rem)

Maximum potential 

annual missed 

nonpenetrating 

dose

(rem)

1949–1958 0.04 Not measured Biweekly 1.04 Not applicable

1950–1971 0.04 0.04 Biweekly 1.04 1.04

1972–1990 0.02 0.038 Monthly 0.24 0.456

1990–1994 0.01 0.035 Monthly 0.12 0.42

1995–present 0.005 0.005 Monthly 0.06 0.06

a. Based on maximum potential exchange frequency in ORAUT-TKBS-0037 (ORAUT 2007a)

6.2 SPECIAL CONSIDERATIONS

Analysis of Data: 1959–1976

All dose records were treated the same and were prorated to 365 days. The data were very 

consistent with 98% of the records exhibiting a wear period of 300 days or greater.

Analysis of Data: 1977–1994

An identifier was created for each record which consists of Social Security Number (SSN), last name, 

and first name.

• This identifier was created so that all badges that were issued to an individual could be 

grouped together to report dose per year per individual.

• The combination of SSN, last name, and first name was chosen as the identifier because not 

all records had all fields but missing fields were generally consistent within a year for an 

individual, which yielded reliable segregation. 

During this period the number of badges that were issued to an individual and the wear periods varied 

greatly. The number of badges varied from 1 to 222, and the “DaysPerBadge” [(Total time a badge 

was issued) ÷ (number of badges issued in a year)] varied from 1 to 366. Averages were 3.4 and 

80.6, respectively. In cases where the “DaysPerBadge” was ≤5, it was assumed that the employee 

did not need to be monitored routinely and was monitored appropriately for all entries into a radiation 

area. These doses were not

7.0

prorated. Only records with a “DaysPerBadge” value >5 were prorated 

to 365 days.

Based on the described information and approaches, SNL coworker annual external dosimetry 

summaries were developed for use in the evaluation of external penetrating and nonpenetrating dose 

COWORKER ANNUAL DOSE SUMMARIES 
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for certain workers who were potentially exposed to workplace radiation but for whom there is no or 

limited monitoring data from DOE. These summaries were developed using the following steps:

Step 1. As described in Section 6.0, the reported penetrating dose was modified for each worker to 

account for partial years of employment. This permits the dose reconstructor to assign an 

appropriate prorated dose to account for partial years of employment or potential exposure.

Step 2. One-half of the maximum potential annual missed doses listed in Table 6-3 were added to 

the reported annual doses from Step 1 (with the exception of reported positive doses, in 

which case the maximum missed dose was reduced by the dose that corresponded to one 

badge exchange because it is not possible that all individual badge results were zero if a 

positive annual dose was reported).

Step 3. The 50th- and 95th-percentile annual coworker gamma doses were derived from the doses 

from Step 2 by ranking the data into cumulative probability curves and extracting the 

50th- and 95th-percentile doses for each year.

Step 4. Table 7-1 lists the results of the coworker analysis. These percentile doses should be used 

for SNL workers with no or limited monitoring data through the use of the methodologies in 

Section 7.0 of ORAUT-OTIB-0020 (ORAUT 2005). In general, the 50th-percentile dose can 

be used as a best estimate of a worker’s dose when professional judgment indicates that the 

worker was probably exposed to intermittent low levels of external radiation. The 

50th-percentile dose should generally not be used for workers who were routinely exposed. 

For routinely exposed workers (i.e., workers who were expected to have been monitored and 

routinely exposed), the 95th-percentile dose should be applied. However, other options are 

available through the guidance in ORAUT-OTIB-0020. For instance, for cases in which 

routine monitoring data exist and coworker dose is used to supplement missing quarters or 

years, the percentile dose should be the one that is consistent with the recorded doses 

unless there is reason to believe that the worker’s job or location in that year differed 

significantly from the job or location during the years dose was recorded. For workers who 

are unlikely to have been exposed, external onsite ambient dose should be used rather than 

coworker doses. 

Step 5. Table 7-2 lists penetrating dose values (as described in the steps above) that have been 

adjusted using the guidance in Section 8.0 of ORAUT-OTIB-0052, Parameters to Consider 

When Processing Claims for Construction Trade Workers (ORAUT 2007b). This guidance is 

applicable for construction trade workers who meet the criteria in Section 3.0 of that TIB. 

Because the TIB does not provide an adjustment factor for nonpenetrating dose, this dose 

component is not shown in this table.

Step 6. If needed, neutron dose (for the period before the implementation of TLD dosimetry in 1971) 

should be calculated using the neutron-to-photon ratios in Table 6-9 of ORAUT-TKBS-0037 

(ORAUT 2007a). These values would be applied to the penetrating dose values in Table 7-1 

below.
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Table 7-1. Annual SNL external coworker doses modified to account

for missed dose (rem).

Year

Penetrating

95th percentile

Penetrating

50th percentile

Nonpenetrating

95th percentile

Nonpenetrating

50th percentile

1959 1.316 0.540 0.560 0.520

1960 0.740 0.520 0.520 0.520

1961 0.830 0.560 0.994 0.600

1962 1.031 0.590 0.796 0.540

1963 0.780 0.550 0.720 0.540

1964 1.432 0.580 0.950 0.540

1965 2.126 0.580 1.120 0.540

1966 2.027 0.600 1.828 0.645

1967 1.414 0.571 1.547 0.561

1968 2.170 0.610 1.701 0.655

1969 2.115 0.610 1.348 0.560

1970 1.603 0.580 1.875 0.570

1971 1.112 0.570 0.610 0.520

1972 0.628 0.160 0.368 0.228

1973 0.458 0.150 0.309 0.228

1974 0.440 0.140 0.289 0.228

1975 0.380 0.150 0.344 0.228

1976 0.320 0.140 0.259 0.228

1977 0.279 0.120 0.279 0.228

1978 0.229 0.120 0.259 0.228

1979 0.191 0.120 0.269 0.228

1980 0.190 0.120 0.257 0.228

1981 0.136 0.120 0.219 0.228

1982 0.150 0.120 0.229 0.228

1983 0.160 0.120 0.229 0.228

1984 0.130 0.120 0.219 0.228

1985 0.151 0.120 0.222 0.228

1986 0.154 0.120 0.228 0.228

1992 0.070 0.060 0.210 0.210

1993 0.157 0.065 0.228 0.210

1994 0.159 0.067 0.231 0.210

Table 7-2. Annual SNL external coworker doses modified in accordance with

ORAUT-OTIB-0052 (rem) (ORAUT 2007b).

Year

Penetrating

95th percentile

Penetrating

50th percentile Year

Penetrating

95th percentile

Penetrating

50th percentile

1959 1.642 0.556 1975 0.488 0.166

1960 0.836 0.520 1976 0.404 0.152

1961 0.962 0.584 1977 0.347 0.120

1962 1.243 0.626 1978 0.277 0.120

1963 0.892 0.570 1979 0.224 0.120

1964 1.805 0.612 1980 0.222 0.120

1965 2.776 0.612 1981 0.146 0.120

1966 2.638 0.640 1982 0.166 0.120

1967 1.780 0.599 1983 0.180 0.120

1968 2.837 0.654 1984 0.138 0.120

1969 2.761 0.654 1985 0.167 0.120

1970 2.044 0.612 1986 0.172 0.120

1971 1.357 0.598 1992 0.076 0.060

1972 0.835 0.180 1993 0.198 0.069

1973 0.598 0.166 1994 0.201 0.072

1974 0.572 0.152
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8.0

All information requiring identification was addressed via references integrated into the reference 

section of this document.

ATTRIBUTIONS AND ANNOTATIONS
Document No. ORAUT-OTIB-0072 Revision No. 00 Effective Date: 09/26/2008 Page 12 of 12

REFERENCES

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, Use of Coworker Dosimetry Data for 

External Dose Assignment, ORAUT-OTIB-0020, Rev. 01, Oak Ridge Tennessee, October 7.

ORAUT (Oak Ridge Associated Universities Team), 2006, Occupational On-Site Ambient Dose 

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

June 28.

ORAUT (Oak Ridge Associated Universities Team), 2007a, Site Profile for Sandia National 

Laboratories in Albuquerque, New Mexico and the Tonopah Test Range, Nevada, ORAUTTKBS-0037, Rev. 00, Oak Ridge, Tennessee, June 22.

ORAUT (Oak Ridge Associated Universities Team), 2007b, Parameters to Consider When 

Processing Claims for Construction Trade Workers, ORAUT-OTIB-0052, Rev. 00 PC-1, Oak 

Ridge, Tennessee, January 16.