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 

Fernald Environmental Management Project

Document Number: ORAUT-OTIB-0073

Revision: 00

Effective Date: 09/22/2008

Type of Document OTIB

Supersedes: None

Subject Expert(s): Keith A. McCartney

Site Expert(s): N/A

Approval: Signature on File Approval Date: 09/22/2008

Matthew H. Smith, Document Owner

Concurrence: Signature on File Concurrence Date: 09/03/2008

James P. Griffin, Deputy Project Director 

Concurrence: Signature on File Concurrence Date: 09/22/2008

Edward F. Maher, Task 5 Manager

Concurrence: Signature on File Concurrence Date: 09/09/2008

Kate Kimpan, Project Director

Approval: Signature on File Approval Date: 09/22/2008

Larry J. Elliott, Director, OCAS

 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-0073 Revision No. 00 Effective Date: 09/22/2008 Page 2 of 12

PUBLICATION RECORD

EFFECTIVE 

DATE

REVISION 

NUMBER DESCRIPTION

09/22/2008 00 Approved new technical information bulletin to provide information to 

allow ORAU Team dose reconstructors to assign doses at the 

Fernald Environmental Management Project to certain workers who 

have no or limited monitoring data, based on site coworker data. 

Incorporates formal internal review comments. No changes occurred 

as a result of NIOSH formal review. Training required: As

determined by the Task Manager. Initiated by Matthew H. Smith.
Document No. ORAUT-OTIB-0073 Revision No. 00 Effective Date: 09/22/2008 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

7.0 Coworker Annual Dose Summaries .........................................................................................7

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

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

LIST OF TABLES

TABLE TITLE

6-1 Missed external doses based on ORAUT-TKBS-0017-6 ..........................................................

PAGE

7

7-1 Annual FEMP external coworker doses modified to account for missed dose .......................... 9

7-2 Annual FEMP external coworker doses modified in accordance with ORAUT-OTIB-0052 ..... 10
Document No. ORAUT-OTIB-0073 Revision No. 00 Effective Date: 09/22/2008 Page 4 of 12

ACRONYMS AND ABBREVIATIONS

DOE U.S. Department of Energy

EEOICPA Energy Employees Occupational Illness Compensation Program Act of 2000

FEMP Fernald Environmental Management Project

IREP Interactive RadioEpidemiological Program

LOD limit of detection

mrem millirem

NIOSH National Institute for Occupational Safety and Health

ORAU Oak Ridge Associated Universities

OW open window

S shielded

TIB technical information bulletin

TLD thermoluminescent dosimeter

U.S.C. United States Code

§ section or sections
Document No. ORAUT-OTIB-0073 Revision No. 00 Effective Date: 09/22/2008 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 that are 

based on site coworker data to Fernald Environmental Management Project (FEMP) workers who 

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

gaps in dosimetry records. 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-0017-6, Technical Basis Document for the Fernald Environmental 

Management Project - Occupational External Dose (ORAUT 2004), operations at the site began in 

1951. FEMP used film dosimeters between 1951 and 1985. Use of a multichip thermoluminescent 

dosimeter (TLD) was implemented in 1985. Exchange frequencies varied from quarterly to weekly 

dependent on the era. 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-0073 Revision No. 00 Effective Date: 09/22/2008 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 FEMP 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

The FEMP HIS-20 database served as the data resource for coworker data analysis. The following 

items describe assumptions made during the analysis process:

COWORKER DATA DEVELOPMENT

• Different types of dosimeters were available in the HIS-20 database. Only records with a wear 

location of “chest” were used in the analysis.

• If a record had a blank Social Security Number, then the record was excluded.

• Deep dose and shallow dose values that were “null” were excluded and not treated as zeros. 

The fact that “null” records were not zero values was confirmed by comparison with DOE 

records from several claimants with the database.

• Dose records from 10 EEOICPA claims were compared to the database, and in all cases the 

results from HIS-20 data exactly matched the data from DOE under EEOICPA. 

• The amount of time a badge was worn by an employee is determined in a calculated field 

called “WearLength” and is equal the number of days between the End_Date and the 

Begin_Date in the database.

○ Only records with a WearLength more than zero and less than 400 days were considered 

in the analysis. Relatively few records were removed from the analysis by filtering the 

records in this way. Of 35,795 records, 35,251 met the filter criteria of a WearLength more 

than zero and less than 400 days. Only 544 records did not meet the filtering criteria.

○ If the WearLength was more than 29 days then the dose was adjusted upward to represent 

365 days of continuous wear. Dose values were used “as is” in the analysis if the 

WearLength is less than or equal to 29 days.
Document No. ORAUT-OTIB-0073 Revision No. 00 Effective Date: 09/22/2008 Page 7 of 12

• The shallow dose represents the sum of the shielded (S) and open window (OW) portions of 

the dosimeter as discussed in Section 6.4 of ORAUT-TKBS-0017-6 (ORAUT 2004).

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 values of a lognormal distribution 

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

Therefore, in the Interactive RadioEpidemiological Program (IREP), Parameter 1 is equal to the 

calculated maximum annual missed doses multiplied by 0.5, and Parameter 2 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 FEMP workers from 1952 to 1953, when they could have been monitored weekly. Table 6-1 lists 

the maximum annual missed dose by monitoring period based on information in ORAUT-TKBS0017-6 (ORAUT 2004).

Table 6-1. Missed external doses (rem) based on ORAUT-TKBS0017-6 (ORAUT 2004).

Monitoring 

period

Penetrating and 

nonpenetrating 

LOD

Exchange 

frequency

Maximum potential 

annual missed 

penetrating and 

nonpenetrating dose

1952–1953 0.04 Weekly 2.080

1954–1958 0.03 Biweekly 0.780

1959–1984 0.03 Monthly 0.360

1985–2006 0.02 Quarterly 0.080

7.0

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

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

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:

COWORKER ANNUAL DOSE SUMMARIES 

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 in Table 6-1 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.
Document No. ORAUT-OTIB-0073 Revision No. 00 Effective Date: 09/22/2008 Page 8 of 12

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

for FEMP 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 2007). 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 should be calculated using the neutron-to-photon ratios in 

Table 6-10 of ORAUT-TKBS-0017-6 (ORAUT 2004). These values would be applied to the 

penetrating dose values in Table 7-1.
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Table 7-1. Annual FEMP external coworker doses modified to account

for missed dose (rem).

Year

Penetrating

95th percentile

Penetrating

50th percentile

Shallow

95th percentile

Shallow

50th percentile

1952 1,520 1,120 4,320 1,220

1953 1,315 1,040 5,332 1,221

1954 776 390 6,291 676

1955 1,177 390 5,088 676

1956 475 390 5,175 675

1957 475 390 5,099 776

1958 576 390 5,990 1,077

1959 366 180 6,482 1,268

1960 565 180 6,565 1,465

1961 867 180 5,881 867

1962 1,168 265 7,094 1,168

1963 1,769 466 9,591 1,870

1964 1,465 365 7,565 1,265

1965 1,484 265 6,798 1,168

1966 967 299 5,520 967

1967 967 265 6,927 1,168

1968 865 180 5,265 665

1969 867 180 5,179 666

1970 967 265 5,580 666

1971 466 180 3,038 366

1972 765 265 4,765 565

1973 571 265 4,176 505

1974 767 265 4,908 566

1975 666 265 3,760 494

1976 665 265 4,435 465

1977 767 179 4,321 369

1978 967 256 5,470 466

1979 867 198 5,078 366

1980 925 265 5,150 465

1981 698 180 4,906 366

1982 808 186 5,542 366

1983 566 172 7,100 274

1984 665 183 6,320 392

1985 431 35 4,843 113

1986 531 36 4,845 51

1987 485 39 3,758 42

1988 289 40 1,509 40

1989 124 40 170 40

1990 96 40 106 40

1991 111 40 115 40

1992 80 40 84 40

1993 62 40 70 40

1994 59 40 61 40

1995 57 40 64 40

1996 57 40 65 40

1997 53 40 54 40

1998 49 40 49 40

1999 43 40 43 40

2000 54 40 54 40

2001 66 40 67 40

2002 88 40 93 40

2003 82 40 83 40

2004 87 40 88 40

2005 206 40 212 40
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Table 7-2. Annual FEMP external coworker

doses modified in accordance with ORAUTOTIB-0052 (rem) (ORAUT 2007).

Year

Penetrating

95th percentile

Penetrating

50th percentile

1952 1,720 1,160

1953 1,433 1,040

1954 937 390

1955 1,498 390

1956 515 390

1957 515 390

1958 656 390

1959 446 180

1960 725 180

1961 1,148 180

1962 1,569 305

1963 2,411 586

1964 1,985 445

1965 2,011 305

1966 1,288 353

1967 1,288 305

1968 1,145 180

1969 1,148 180

1970 1,288 305

1971 586 180

1972 1,005 305

1973 734 305

1974 1,007 305

1975 867 305

1976 865 305

1977 1,007 184

1978 1,288 293

1979 1,148 211

1980 1,229 305

1981 912 186

1982 1,065 194

1983 727 175

1984 865 190

1985 592 37

1986 732 39

1987 667 43

1988 392 40

1989 162 40

1990 122 40

1991 143 40

1992 100 40

1993 75 40

1994 71 40

1995 67 40

1996 68 40

1997 62 40

1998 57 40

1999 48 40

2000 64 40

2001 81 40

2002 112 40

2003 103 40

2004 110 40

2005 276 40
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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-0073 Revision No. 00 Effective Date: 09/22/2008 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), 2004, Technical Basis Document for the Fernald 

Environmental Management Project - Occupational External Dose, ORAUT-TKBS-0017-6, 

Rev. 00, Oak Ridge, Tennessee, April 20.

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

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

Tennessee, January 16.