DISCLAIMER; This is a working document provided by the Centers for Disease Control and Prevention (CDC) 

technical support contractor, SC&A, for use in discussions with the National Institute for Occupational Safety and 

Health (NIOSH) and the Advisory Board on Radiation and Worker Health (ABRWH), including its Working Groups 

or Subcommittees. Documents produced by SC&A, such as memorandum, white paper, draft or working documents 

are not final NIOSH or ABRWH products or positions, unless specifically marked as such. This document prepared 

by SC&A represents its preliminary evaluation on technical issues.

NOTICE: This document has been reviewed to identify and redact any information that is protected by the 

Privacy Act 5 USC §552a and has been cleared for distribution. 

MEMORANDUM

TO: Savannah River Site Work Group 

FROM: SC&A, Inc.

DATE: January 31, 2018 

SUBJECT: SC&A’s ORAUT-OTIB-0075 Findings of 2010 and 2017 

Introduction and Background

The documents relevant to this discussion are:

• ORAUT-OTIB-0075, Revision 00, Use of Claimant Datasets for Coworker Modeling, 

May 25, 2009 (NIOSH 2009; hereafter “OTIB-0075, Revision 00”) 

• ORAUT-OTIB-0075, Revision 01, Use of Claimant Datasets for Coworker Modeling, 

June 17, 2016 (NIOSH 2016a; hereafter “OTIB-0075, Revision 01”) 

• ORAUT-OTIB-0081, Revision 03, Internal Coworker Dosimetry Data for the Savannah 

River Site, November 22, 2016 (NIOSH 2016b; hereafter “OTIB-0081”) 

• SC&A 2010 report, SC&A-200-2009-28555, Revision 0, Review of ORAUT-OTIB-0075: 

Use of Claimant Datasets for Coworker Modeling for Construction Workers at Savannah 

River Site, January 13, 2010 (SC&A 2010) 

• SC&A 2017 report, SCA-TR-2017-PR011, Revision 0, SC&A’s Evaluation of ORAUTOTIB-0075, Revision 01, “Use of Claimant Datasets for Coworker Modeling,”

October 9, 2017 (SC&A 2017) 

SC&A reviewed OTIB-0075, Revision 00 (NIOSH 2009), in 2010 (SC&A 2010). SC&A’s 

report provided an overall review of OTIB-0075, Revision 00, and further expanded on 

Section 7.0 of OTIB-0075 concerning the Savannah River Site (SRS) data. In that expanded 

analysis, SC&A pointed out the need to look at possible stratification of coworker intake data 

according to radionuclide, work area, and craft for construction trade workers (CTWs) and 

non-CTWs.

After the National Institute for Occupational Safety and Health (NIOSH) issued OTIB-0075, 

Revision 01 (NIOSH 2016a), SC&A provided a report (SC&A 2017) that evaluated the revised 

OTIB-0075 to determine if the original findings identified in SC&A’s 2010 report were resolved. 

The following is a summary of the current status of SC&A’s review of OTIB-0075, Revisions 00 

and 01, and the related findings. 
Memo – SC&A’s ORAUT-OTIB-0075 Findings 2 SC&A – January 31, 2018 

NOTICE: This document has been reviewed to identify and redact any information that is protected by the 

Privacy Act 5 USC §552a and has been cleared for distribution. 

Status of Evaluation of ORAUT-OTIB-0075 

Evaluation of ORAUT-OTIB-0075, Revision 00 

In OTIB-0075, Revision 00 (NIOSH 2009), NIOSH compared the intake values in the site’s 

complete dataset to the intake values in the NIOSH OCAS Claimant Tracking System (NOCTS) 

to illustrate that the NOCTS dataset represents a sample of the complete dataset for use in a 

coworker intake model. The datasets for the following sites were analyzed: 

• Y-12: Uranium urine bioassays, 1950–1988 

• Mound Laboratory: Plutonium urine bioassay, 1960–1990 

• SRS: Tritium dose, 1991–2000 

In its 2010 analysis of OTIB-0075, Revision 00, SC&A: 

• Agreed with the results for Y-12 uranium data results. 

• Disagreed with the plutonium data results. 

• Agreed with the SRS tritium data results, with the caution that the results only apply to 

tritium for that period and could not be extrapolated to other radionuclides and time 

periods without supporting evidence. 

Evaluation of ORAUT-OTIB-0075, Revision 01 

NIOSH added more entries into the datasets in OTIB-0075, Revision 01 (NIOSH 2016a). SC&A 

analyzed the new data and issued a report in 2017 (SC&A 2017), which can be summarized as 

follows (the finding numbers are the same in both the 2010 and the 2017 SC&A reviews): 

• Finding 1: At the Y-12 Plant, the complete (all-worker) and claimant datasets for 

uranium in urine from 1950 to 1988 show no significant difference at the annual level of 

aggregation. This finding confirms the conclusions reached in OTIB-0075 for uranium at 

the Y-12 Plant. 

This was a statement that SC&A concurs with NIOSH’s results. Therefore, this presently 

would be considered an observation instead of a finding. SC&A recommends that this 

item be closed. 

• Finding 2: At the Mound Laboratory, the complete (all-worker) and claimant datasets 

for plutonium in urine from 1960 to 1990 show significant differences at the annual level 

of aggregation. This finding raises questions concerning the conclusions reached in 

OTIB-0075 for plutonium at the Mound Laboratory.

SC&A found that the new NOCTS dataset for plutonium intakes at Mound Laboratory 

statistically represented the intakes in the complete dataset. This resolved Finding 2 of 

SC&A (2010). SC&A recommends closure of Finding 2. 
Memo – SC&A’s ORAUT-OTIB-0075 Findings 3 SC&A – January 31, 2018 

NOTICE: This document has been reviewed to identify and redact any information that is protected by the 

Privacy Act 5 USC §552a and has been cleared for distribution. 

• Finding 3: At SRS, the complete (all-worker) and claimant datasets for annual tritium 

doses from 1991 to 2001 show no significant difference at the annual level of 

aggregation, but the sample size is very small and the regression results were dominated 

by a single year with high exposure, 1991. If this year is omitted, the complete and 

claimant datasets for annual tritium doses period from 1992 through 2001 again show no 

significant difference at the annual level of aggregation.

This was a statement that SC&A concurred with NIOSH’s results but cautioned that they

cannot be extrapolated to other radionuclides and time periods. Therefore, this presently 

would be considered an observation instead of a finding. SC&A recommends that this

item be closed.

• Finding 6: At Y-12, only 37% of all claimants (3 out of 8) have data in the “complete” 

Y-12 uranium urine bioassay coworker database for 1950 to 1988. This subset of 731 

claimants with uranium bioassay data had a total of approximately 70,000 bioassays. 

OTIB-0075, Revision 00, page 10, footnote 7, states that out of 1971 claimants, 731 

claimants had bioassay records in the complete dataset, which is 37%. 

OTIB-0075, Revision 01, page 8, states that a total of 1,585 claimants submitted 119,044 

uranium urine samples. However, there was no indication in the text or footnotes of how 

many total claimants there were. Therefore, with the present information, SC&A could 

not determine the fraction of the number of claimants who were monitored (i.e., had 

bioassay records in the complete dataset) compared to the total number of claimants in 

the dataset to determine if Finding 6 has been resolved by the new data. At this point, the 

item could be consider an observation instead of a finding because it requests 

clarification or additional information. Therefore, this item remains open. 

• Findings 4, 5, 7, 8, 9, 10, 11, 12, and 13: In 2010, SC&A performed example analyses of 

NOCTS data that led to these findings (SC&A 2010), which indicate that there could be 

stratification of coworker data by radionuclide, work area, or job type within the CTW 

and non-CTW groups, and between the two groups. Finding 7 was related to the Y-12 

dataset, and Finding 8 was related to the Mound Laboratory dataset; the remaining 

Findings 4, 5, 9, 10, 11, 12, and 13 were all related to the SRS dataset. In OTIB-0075, 

Revision 01, NIOSH (2016a) illustrated that NOCTS datasets statistically represent

complete datasets for certain radionuclides, for some sites, during specific time periods, 

but did not address possible radionuclide, work area, or job type stratification in the 

coworker data.

Suggested Path Forward 

SC&A suggests the following course of action: 

• Findings 1 and 3 can be closed because they only stated that SC&A concurred with the 

results, which would be considered observations by today’s criteria. 
Memo – SC&A’s ORAUT-OTIB-0075 Findings 4 SC&A – January 31, 2018 

NOTICE: This document has been reviewed to identify and redact any information that is protected by the 

Privacy Act 5 USC §552a and has been cleared for distribution. 

• Finding 2 can be closed because it has been resolved by the addition data for Mound 

Laboratory. 

• Finding 6 is a request for additional information concerning the total number of claimants 

in the dataset. SC&A will review this information when it becomes available, and if there 

is not a finding, this item could become a resolved observation. 

• Findings 7 and 8 (for Y-12 and Mound Laboratory, respectively) can be closed because 

they are not applicable to OTIB-0075, Revisions 00 and 01. The original purpose of 

OTIB-0075 did not include addressing stratification or site-specific issues. In SC&A’s 

original 2010 report, SC&A was using these as illustrative examples.

• Findings 4, 5, 9, 10, 11, 12, and 13 concerning SRS dataset stratification can be 

considered, as needed and if applicable, in the resolution of SRS dose reconstruction 

issues. These finding would be removed from consideration concerning OTIB-0075, 

Revisions 00 and 01, because the findings are more applicable to current SRS issues than 

to OTIB-0075. 

Clarification Concerning ORAUT-OTIB-0081, Internal Coworker Dosimetry Data for the 

Savannah River Site

One of the current issues for dose reconstruction at SRS is the question of subcontractor CTW 

intakes versus prime contractor CTW intakes. This issue was not addressed in OTIB-0081, 

Revision 03 (NIOSH 2016b), which was mentioned in the SRS Work Group meeting of 

November 14, 2017. In OTIB-0081, NIOSH addressed the stratification of SRS intakes between 

CTWs and non-CTWs for:

• Americium-241 intake, solubility Type M, for the period 1964–1989 

• Tritium dose for the period 1954–1990 

• Thorium-232 intake, solubility Types M and S, for the period 1972–1989 

OTIB-0081, Revision 03, pages 34 and 35, provides summary tables of the recommended 

intakes, or doses, for unmonitored workers. 

As can be seen from the list above, OTIB-0081 does not address work areas or job types, nor 

does it address all the major potential SRS radionuclides or time periods needed for dose 

reconstruction. 

Summary

SC&A recommends that (1) Findings 1, 2, 3, 7, and 8 be closed, (2) Finding 6 be resolved with 

clarification or additional data, and (3) the data generated by SC&A in deriving Findings 4, 5, 9, 

10, 11, 12, and 13 be used as needed, and appropriate, to address intake issues at SRS.
Memo – SC&A’s ORAUT-OTIB-0075 Findings 5 SC&A – January 31, 2018 

NOTICE: This document has been reviewed to identify and redact any information that is protected by the 

Privacy Act 5 USC §552a and has been cleared for distribution. 

References

NIOSH 2009. Use of Claimant Datasets for Coworker Modeling, ORAUT-OTIB-0075, 

Revision 00, National Institute for Occupational Safety and Health, Cincinnati, Ohio. May 25, 

2009. 

NIOSH 2016a. Use of Claimant Datasets for Coworker Modeling, ORAUT-OTIB-0075, 

Revision 01, National Institute for Occupational Safety and Health, Cincinnati, Ohio. June 17, 

2016. 

NIOSH 2016b. Internal Coworker Dosimetry Data for the Savannah River Site, ORAUT-OTIB0081, Revision 03, National Institute for Occupational Safety and Health, Cincinnati, Ohio.

November 22, 2016. 

SC&A 2010. Review of ORAUT-OTIB-0075: Use of Claimant Datasets for Coworker Modeling 

for Construction Workers at Savannah River Site, SC&A-200-2009-28555, Revision 0, SC&A, 

Inc., Vienna, Virginia, and Saliant, Inc., Jefferson, Maryland. January 13, 2010. 

SC&A 2017. SC&A’s Evaluation of ORAUT-OTIB-0075, Revision 01, “Use of Claimant 

Datasets for Coworker Modeling,” SCA-TR-2017-PR011, Revision 0, SC&A, Inc., Vienna, 

Virginia, and Saliant, Inc., Jefferson, Maryland. October 9, 2017.