ORAU TEAM

Dose Reconstruction

Project for NIOSH

Oak Ridge Associated Universities I Dade Moeller I MJW Technical Services

Page 1 of 10

DOE Review Release 08/26/2009

Document Title:

External Coworker Dosimetry Data for Area IV of 

the Santa Susana Field Laboratory, the Canoga 

Avenue Facility (Vanowen Building, and the De 

Soto Avenue Facility (sometimes referred to as 

Energy Technology Engineering Center [ETEC] or 

Atomics International)

Document Number: ORAUT-OTIB-0077

Revision: 00

Effective Date: 08/03/2009

Type of Document OTIB

Supersedes: None

Subject Expert(s): Matthew H. Smith

Site Expert(s): N/A

Approval: Signature on File Approval Date: 06/29/2009

Matthew H. Smith, Document Owner

Concurrence: Signature on File Concurrence Date: 06/30/2009

John M. Byrne, Objective 1 Manager

Concurrence: Keith A. McCartney Signature on File for Concurrence Date: 07/21/2009

Edward F. Maher, Objective 3 Manager

Concurrence: Signature on File Concurrence Date: 07/13/2009

Kate Kimpan, Project Director

Approval: Signature on File Approval Date: 08/03/2009

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-0077 Revision No. 00 Effective Date: 08/03/2009 Page 2 of 10

PUBLICATION RECORD

EFFECTIVE 

DATE

REVISION

NUMBER DESCRIPTION

08/03/2009 00 New technical information bulletin to provide external coworker data 

for Santa Susana workers. Incorporates formal internal and NIOSH 

review comment. Training required: As determined by the Objective 

Manager. Initiated by Matthew H. Smith.
Document No. ORAUT-OTIB-0077 Revision No. 00 Effective Date: 08/03/2009 Page 3 of 10

TABLE OF CONTENTS

SECTION TITLE

1.0 Purpose ...................................................................................................................................

PAGE

4

2.0 Background..............................................................................................................................4

3.0 General Approach....................................................................................................................4

4.0 Applications and Limitations.....................................................................................................5

5.0 Coworker Data Development ...................................................................................................5

5.1 Dosimetry Data.............................................................................................................5

5.2 Adjustment for Missed Dose.........................................................................................5

6.0 Coworker Annual Dose Summaries .........................................................................................6

7.0 Attributions and Annotations ....................................................................................................7

References ........................................................................................................................................10

LIST OF TABLES

TABLE TITLE

1 Missed external doses .............................................................................................................

PAGE

6

2 Annual external coworker doses modified to account for missed dose..................................... 8

3 Annual external coworker doses modified in accordance with ORAUT-OTIB-0052 .................. 9
Document No. ORAUT-OTIB-0077 Revision No. 00 Effective Date: 08/03/2009 Page 4 of 10

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.

PURPOSE

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)].

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

based on site coworker data to workers who were employed at Area IV and associated sites and for 

whom there are no or limited monitoring data. For convenience, this TIB refers to these workers as 

Santa Susana Field Laboratory (SSFL) workers regardless of employment location and employer.

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 2008).

2.0

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 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 2008), 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.

3.0

As described in ORAUT-OTIB-0020 (ORAUT 2008), 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
Document No. ORAUT-OTIB-0077 Revision No. 00 Effective Date: 08/03/2009 Page 5 of 10

4.0

Some SSFL 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 information for 

external coworker dosimetry data for all relevant sites.

APPLICATIONS AND LIMITATIONS

The data in this TIB address penetrating gamma and neutron radiation. 

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 2006a) and 

ORAUT-TKBS-0038-4, Area IV of the Santa Susana Field Laboratory, the Canoga Avenue Facility 

(Vanowen Building), the Downey Facility, and the De Soto Avenue Facility (sometimes referred to as 

Energy Technology Engineering Center [ETEC] or Atomics International) – Occupational 

Environmental Dose (ORAUT 2007a).

5.0

5.1 DOSIMETRY DATA

COWORKER DATA DEVELOPMENT

The SSFL data was manually entered into a database for an epidemiological study of workers at 

Rocketdyne (Atomics International) covering the period 1948 to 1999. Exposure information was 

compiled from the following sources: Rocketdyne radiation safety folders, NRC - REIRS, DOEREMS, Landauer dosimetry, Individual facilities, the U.S. Army, and the U.S. Air Force. 6,675 

workers were monitored for radiation exposure and of those 5,801 were included in the study. 350

workers who were employed for less than 6 months and 524 workers with insufficient identifying 

information were excluded from the study (Boice 2006). Also note that these data include results from 

workers who had duties at the Canoga, DeSoto, and Downey sites. The number of datapoints used 

for each year is shown in Tables 2 and 3. 

The SSFL database contains dosimetry data for penetrating dose, which is a combination of gamma 

and fast neutron dose. Because it was difficult to separate statistically significant neutron dose from 

the penetrating dose, and because shallow dose data is not available in the database described 

above, the neutron dose component (which represented less than 5% of the total data points 

available) was left embedded with gamma dose, resulting in penetrating dose values that are 

favorable to claimants. An analysis of average neutron dose revealed that the average value for any 

individual year was bounded by the 95th percentile values for penetrating dose given in this OTIB. 

5.2 ADJUSTMENT FOR MISSED DOSE

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

missed doses are to be 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 of less than one-half the applicable minimum detection 

limits are to be 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 
Document No. ORAUT-OTIB-0077 Revision No. 00 Effective Date: 08/03/2009 Page 6 of 10

deviation, respectively, for each year of analysis. Table 1 lists the maximum annual missed dose by 

monitoring period.

Table 1. Missed external doses (rem).

Monitoring 

period

Penetrating 

LOD

Exchange 

frequency

Maximum potential annual 

missed penetrating dose

1948–1962 0.04 Weekly 2.08

1963–1979 0.04 Monthly 0.480

1980–present 0.01 Quarterly 0.040

6.0

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

summaries were developed for use in the evaluation of external penetrating 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. 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 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 penetrating 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 2 lists the results of the coworker analysis. These percentile doses should be used for 

SSFL workers for whom there are no or limited monitoring data using the methodologies in 

Sections 5.0 and 6.0 of ORAUT-OTIB-0020 (ORAUT 2008). 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 3 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. 
Document No. ORAUT-OTIB-0077 Revision No. 00 Effective Date: 08/03/2009 Page 7 of 10

The data from Tables 2 and 3 should be used with the appropriate dose conversion factors and sitespecific correction factors as discussed in the external section of the site profile Atomics International 

– Occupational External Dose (ORAUT 2006b).

7.0

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

section of this document.

ATTRIBUTIONS AND ANNOTATIONS
Document No. ORAUT-OTIB-0077 Revision No. 00 Effective Date: 08/03/2009 Page 8 of 10

 Table 2. Annual external coworker doses modified to account for 

missed dose (mrem).

Year

Penetrating

95th percentile

Penetrating

50th percentile

Number of 

Datapoints

1948 6,335 1,070 46

1949 4,261 1,140 74

1950 3,190 1,835 118

1951 3,124 1,084 224

1952 1,849 1,118 276

1953 2,037 1,125 298

1954 2,480 1,062 369

1955 3,269 1,057 435

1956 2,211 1,073 374

1957 1,890 1,077 621

1958 3,116 1,032 797

1959 2,523 1,035 1031

1960 2,775 1,065 1412

1961 2,229 1,080 1447

1962 2,544 1,440 1983

1963 970 270 2063

1964 1,710 280 1905

1965 1,875 360 1554

1966 1,286 240 1023

1967 860 230 938

1968 886 225 813

1969 848 240 744

1970 1,938 240 717

1971 718 240 615

1972 807 240 504

1973 640 230 519

1974 670 240 522

1975 676 240 609

1976 850 230 717

1977 1,015 235 748

1978 1,038 240 843

1979 823 240 827

1980 290 35 811

1981 293 35 847

1982 847 35 864

1983 1,325 25 781

1984 445 25 701

1985 915 20 639

1986 338 20 639

1987 318 20 572

1988 218 20 588

1989 794 20 584

1990 422 20 502

1991 573 20 437

1992 100 20 914

1993 75 20 928

1994 55 20 926

1995 45 20 891

1996 54 20 883

1997 95 20 891

1998 35 20 896

1999 28 20 889
Document No. ORAUT-OTIB-0077 Revision No. 00 Effective Date: 08/03/2009 Page 9 of 10

 Table 3. Annual external coworker doses modified in accordance with ORAUT-OTIB0052 (mrem) (ORAUT 2007b).

Year

Penetrating

95th percentile

Penetrating

50th percentile

Number of 

Datapoints

1948 8,461 1,090 46

1949 5,557 1,188 74

1950 4,057 2,161 118

1951 3,965 1,109 224

1952 2,181 1,157 276

1953 2,444 1,167 298

1954 3,064 1,079 369

1955 4,169 1,072 435

1956 2,687 1,094 374

1957 2,238 1,100 621

1958 3,954 1,037 797

1959 3,124 1,041 1031

1960 3,477 1,083 1412

1961 2,712 1,104 1447

1962 3,153 1,608 1983

1963 1,270 290 2063

1964 2,306 304 1905

1965 2,537 416 1554

1966 1,712 248 1023

1967 1,116 234 938

1968 1,152 227 813

1969 1,099 248 744

1970 2,625 240 717

1971 917 248 615

1972 1,042 240 504

1973 808 234 519

1974 849 240 522

1975 858 240 609

1976 1,102 234 717

1977 1,332 241 748

1978 1,365 248 843

1979 1,064 248 827

1980 400 43 811

1981 404 43 847

1982 1,180 43 864

1983 1,849 29 781

1984 617 29 701

1985 1,275 20 639

1986 467 20 639

1987 440 20 572

1988 299 20 588

1989 1,105 20 584

1990 585 20 502

1991 796 20 437

1992 135 20 914

1993 99 20 928

1994 71 20 926

1995 57 20 891

1996 70 20 883

1997 127 20 891

1998 43 20 896

1999 33 20 889
Document No. ORAUT-OTIB-0077 Revision No. 00 Effective Date: 08/03/2009 Page 10 of 10

REFERENCES

Boice, J. D., 2006, Mortality Among Radiation Workers at Rocketdyne (Atomics International), 1948-

1999, Radiation Research Vol. 166, pp. 98-115 (2006). [SRDB Ref ID: 39396]

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), 2006a, Occupational Onsite Ambient Dose 

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

June 28.

ORAUT (Oak Ridge Associated Universities Team), 2006b, Atomics International – Occupational 

External Dose, ORAUT-TKBS-0038-6, Rev. 01, Oak Ridge, Tennessee, November 16.

ORAUT (Oak Ridge Associated Universities Team), 2007a, Area IV of the Santa Susana Field 

Laboratory, the Canoga Avenue Facility (Vanowen Building), the Downey Facility, and the 

De Soto Avenue Facility (sometimes referred to as Energy Technology Engineering Center 

[ETEC] or Atomics International – Occupational Environmental Dose, ORAUT-TKBS-0038-4, 

Rev. 01, Oak Ridge, Tennessee, March 8.

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.

ORAUT (Oak Ridge Associated Universities Team), 2008, Use of Coworker Dosimetry Data for 

External Dose Assignment, ORAUT-OTIB-0020, Rev. 02, Oak Ridge Tennessee, December 4.