Office of Compensation Analysis and 

Support

Program Evaluation Report 

Document Number: 

 OCAS-PER-001 

Effective Date: 

 09/08/2003 

Revision No. 0 

Misinterpreted dosimetry records resulting in an underestimate of 

Page 1 of 4 missed dose in SRS dose reconstructions

Page 1 of 4

 

Approval: Signature on File Date: 9/09/2003 J.W. Neton, Associate Director for Science 

Supersedes: 

 None 

RECORD OF ISSUE/REVISIONS

ISSUE 

AUTHORIZATION 

DATE

EFFECTIVE 

DATE

REV. 

NO.

DESCRIPTION

09/08/2003 09/08/2003 0 

New document to evaluate the programmatic 

effect of the misinterpreted dosimetry records 

resulting in an underestimate of the missed dose 

for Savannah River Site (SRS) Dose 

Reconstructions 

1.0 Description

On September 4, 2003, an error in the interpretation of incomplete Savannah River Site 

dosimetry records between 1973 and 1988 was identified in the course of dose reconstruction review. 

Until this date, data gaps (missing dosimetry badge cycle information) were interpreted to indicate that 

the energy employee was not monitored for radiation exposure. NIOSH has since learned through 

conversations with site dosimetry personnel, 1

 that a missing dosimeter badge cycle on the “SLHP3” 

form could indicate 1) the energy employee was not monitored, 2) the energy employee was monitored 

and the result was below the limit of detection. In addition, the absence of an entire year from the 

SLHP3 form could result from 1) the data for that year was below the limit of detection, 2) the worker 

was not monitored for radiation exposure during that year (i.e., did not enter a radiological control area), 

or 3) a combination of both unmonitored and below the limit of detection for a given year. The result of 

this misinterpretation is that the missed dose was not added between the years 1973-1988 when no 
information was provided on the SLHP3 form,

was added to the dose reconstruction.

During these years, only the onsite ambient dose

2.0 Evaluation

2. 1 Dose Evaluation

During August 2003, the ORAU team recognized that the SRS Technical Basis Document2

(ORAUT -TKBS-0003 Rev 0) contained a significant overestimate of the onsite ambient dose

between 1974 and 1998. Since this error resulted in an overestimate of the energy employee's

onsite ambient dose (claimant favorable), no formal Program Evaluation Report (PER) was

written. These values were corrected and noted in the revision of ORAUT - TKBS-0003 Rev 013

approved on August 21, 2003.

The dose reconstructions effected .by the misinterpretation of the dosimetry records were

conducted under Rev 002 of the SRS Technical Basis Document and cover similar years of

exposure. Table 1 provides a comparison of the difference in onsite ambient dose between Rev

002 and Rev 013 of the SRS Technical Basis Documents and the associated missed dose

(LOD/2) for the corresponding year.

Table 1 Comparison of the overestimated missed dose in Rev 00 with the missed dose due to

misinterDretation of the dosl!!1etry records. All values are In cS~~

Ambient Onsite

Rev. 002

Overestimate

(Rev 002 - R~)-

Ambient Onsite

-Year Rev. 013

1973

1974

~

..!!Z!-

1977

1978

1979

-.1!!9..

1981

1982

1983

1984

1985

1986

1987

1988 ~

Totals

Missed Dose

0.090

0.090

0.090

0.090

0.090

0.090

0.090

0.090

0.090

0.090

0.090

0.030

0.030

0.030

0.030

0.030

1.140

~

~

0.210

~

0.240 -

~

0.161

~

~

0.178

0.166

0.156

0.584

0.146

~

0.209 -

3.143

0.099

~

0.085

0.068

0.090

0.061

0.065

0.044

0.074

0.065

0.069

0.093

0.114

0.059

0.053 -,--

-0.050

1.178

0.000

0.121

0.125

0.110

0.150

0.105

0.096

0.056

0.151

0.113

0.097

0.063

0.470

0.087

0.062

0.159 --

1.966

Overestimate -

Missed Dose

-0.090

0.031

0.035

O.O~O

O.Q!Q

0.015

0,006

-0.034

0.06~

0.023

0,007

0.033

0.440

0,057

0.032

0.129

0.826
Table 1 indicates that on an annual basis the overestimate of the onsite ambient dose usually

(88%) exceeded the median missed dose (LOD/2). If an energy employee worked the entire

time period, his estimated dose would be overestimated by approximately 0.8 cSv, however, it

should be noted that approximately 0.4 cSv (50%) is the result of one year (1985).

2.2 Probability of Causation (PC) Evaluation

Since missed dose reconstructed in accordance with NIOSH's External Dose Reconstruction

Implementation Guideline4 (OCAS-IG-001) is not a single value but an uncertainty distribution

with the upper 95th percentile calculated using the Limit of Detection (LOD) and since this

portion of the uncertainty distribution exceeded the onsite ambient dose overestimate 70% of

the time, a comparison of the probability of causation over the time period was conducted. In

the dose reconstructions completed under Rev 002 of the SRS Technical Basis Document, a

constant was used for the onsite ambient dose.

Table 2 provides a comparison of the probability of causation (PC) for a 60 year old male first

exposed at age 30 using the overestimated difference in onsite ambient dose between Rev 002

and Rev 013 as a constant and comparing the PC calculated using the missed dose uncertainty

distribution. The cancers listed comprised the top ten cancer models (N85%) of the SRS claims

currently in review or approved and forwarded to the Department of Labor as of September 4,

2003.

This table indicates that the PC at the 99th percentile was slightly greater for the onsite ambient

dose compared to the missed dose. Even though the upper portion of the missed dose

uncertainty distribution exceeded the differential in the onsite ambient dose, the resultant

probability of causation would still be overestimated (Claimant favorable).

In summary the two errors (overestimate of onsite ambient dose and underestimate from missed

dose) effectively offset each other with a slight bias in a claimant favorable direction (i.e. higher
PC value). Thus the programmatic effect this misinterpretation has on previous dose

reconstructions and dose reconstructions currently undergoing review has been determined to

be insignificant.

Resolution I Corrective Action

The immediate resolution was to start interpreting the records correctly and guidance was set

forth in OCAS- TIB-00065 issued on September 8, 2003. This Technical Information Bulletin

(TIB) provides specific guidance on the interpretation of the SLHP3 form.

Since the onsite ambient doses were overestimated and the difference offset the underestimated

missed dose resulting in a more claimant favorable probability of causation, the misinterpretation

of the dosimetry records has negligible impact on the current program. No further evaluation is

necessary and dose reconstructions conducted using the SRS Technical Basis Document Rev

002 that have this misinterpretation can be approved by the OCAS reviewer providing there are

no other substantial errors in the dose reconstruction methodology.

Summary

While the underestimated missed dose resulted in a non-claimant favorable estimate of missed

dose, the overestimated onsite ambient dose offset this underestimate. As a result, no further

evaluation is necessary since the offset still resulted in a slight claimant favorable bias in the

dose estimate and resulting probability of causation.

References

1 Savannah River Site (2003), Telephone Conversation between Russ Morgan (SRS Dosimetry

Records) and Tim Taulbee NIOSH, September 4, 2003.

2. ORAU Team, Technical Basis Document for the Savannah River Site To Be Used for

EEOICPA Dose Reconstructions, ORAUT -TKBS-OO03 Rev 00, (2003).

3. ORAU Team, Technical Basis Document for the Savannah River Site To Be Used for

EEOICPA Dose Reconstructions, ORAUT - TKBS-OOO3 Rev 01, (2003).

4, NIOSH, External Dose Reconstruction Implementation Guideline,OCAS-IG-001 Rev 01,

National Institute for Occupational Safety and Health, Office of Compensation Analysis and

Support, Cincinnati, Ohio (2002).

5. NIOSH, OCAS- TIB-OOOS, Interpretation of External Dosimetry Records at the Savannah River

Site (2003).