Draft White Paper 

REVIEW OF ORAUT-OTIB-0075: USE OF CLAIMANT DATASETS FOR 

COWORKER MODELING FOR CONSTRUCTION WORKERS AT 

SAVANNAH RIVER SITE

Contract Number 200-2009-28555 

Prepared by 

S. Cohen & Associates 

1608 Spring Hill Road, Suite 400 

Vienna, Virginia 22182 

Saliant, Inc. 

5579 Catholic Church Road 

Jefferson, Maryland 21755 

January 2010 

Disclaimer 

This document is made available in accordance with the unanimous desire of the Advisory Board on 

Radiation and Worker Health (ABRWH) to maintain all possible openness in its deliberations. However, 

the ABRWH and its contractor, SC&A, caution the reader that at the time of its release, this report is predecisional and has not been reviewed by the Board for factual accuracy or applicability within the 

requirements of 42 CFR 82. This implies that once reviewed by the ABRWH, the Board’s position may 

differ from the report’s conclusions. Thus, the reader should be cautioned that this report is for 

information only and that premature interpretations regarding its conclusions are unwarranted.
SRS – Draft Review of OTIB-0075 2 SC&A – January 13, 2010 

NOTICE: This report has been reviewed for Privacy Act information and has been cleared for distribution. 

However, this report is pre-decisional and has not been reviewed by the Advisory Board on Radiation and Worker 

Health for factual accuracy or applicability within the requirements of 42 CFR 82. 

TABLE OF CONTENTS 

1.0 Introduction and Summary of Findings ...............................................................................7 

1.1 Findings with Summary of Analysis .....................................................................10 

1.1.1 Y-12 Claimants and All-Worker Uranium Data........................................10 

1.1.2 Mound Claimant and All-Worker Data .....................................................10 

1.1.3 SRS Claimant and All-Worker Data, Tritium............................................11 

1.1.4 SRS Data for Radionuclides Other than Tritium in ORAUT-OTIB0075............................................................................................................11 

1.1.5 Proposed SRS Data Aggregation for All Claimants..................................11 

1.1.6 Completeness of Y-12 Uranium Data used in ORAUT-OTIB-0075.........12 

1.1.7 Y-12 Data Aggregation in the Coworker Model .......................................12 

1.1.8 Aggregation of Mound Data ......................................................................12 

1.1.9 Findings Specific to SRS ...........................................................................13 

2.0 Review of the Study Conducted by NIOSH ......................................................................15 

2.1 Comparison of Claimant and Complete Datasets for Uranium at the Y-12 

Plant .......................................................................................................................15 

2.2 Comparison of Claimant and Complete Datasets for Plutonium at Mound 

Laboratory..............................................................................................................19 

2.3 Comparison of Claimant and Complete Datasets for Tritium at SRS ...................24 

3.0 Overview Comments on OTIB-0075.................................................................................29 

4.0 Analysis of SRS Claimant Exposures by Work Area and Job Type .................................32 

4.1 Comparison of Non-Construction Worker Exposures by Work Area...................33 

4.2 Comparison of Construction Worker and Non-Construction Worker 

Exposures...............................................................................................................40 

4.3 Comparison of Construction Worker Exposures by Area .....................................45 

5.0 Analysis of SRS Construction Worker Claimant Exposure by Craft ................................51 

6.0 Overall Conclusions...........................................................................................................55 

6.1 Conclusions Regarding ORAUT-OTIB-0075 .......................................................55 

6.2 SRS Construction Worker Coworker Model .........................................................55 

7.0 References..........................................................................................................................56 

Appendix A: Sample Size and 84th Percentiles of Non-Construction Worker Bio-samples ........57 

Appendix B: Sample Size and 84th Percentiles of Construction Worker Bio-samples ................61 

Appendix C: Sample Size and 84th Percentiles of Construction Worker Tritium Biosamples by Craft ................................................................................................................65 
SRS – Draft Review of OTIB-0075 3 SC&A – January 13, 2010 

NOTICE: This report has been reviewed for Privacy Act information and has been cleared for distribution. 

However, this report is pre-decisional and has not been reviewed by the Advisory Board on Radiation and Worker 

Health for factual accuracy or applicability within the requirements of 42 CFR 82. 

LIST OF TABLES 

Table 2-1: Summary of Regression Comparisons of Complete (All-Worker) and 

Claimant-Only Distributions for Uranium at the Y-12 Plant.................................17 

Table 2-2: Summary of Regression Comparisons of Complete (All-Worker) and 

Claimant-Only Distributions for Plutonium at Mound Laboratory .......................23 

Table 2-3: Summary of Regression Comparisons of Complete (All-Worker) and 

Claimant-Only Distributions for Tritium at SRS...................................................29 

Table 4-1: Ratio of 84th Percentile for Non-Construction Workers in Specified Work 

Areas over 84th Percentile for Non-Construction Workers in All Work 

Areas ......................................................................................................................34 

Table 4-2: Ratio of GSD for Non-Construction Workers in Specified Work Areas over 

GSD for Non-Construction Workers in All Work Areas.......................................36 

Table 4-3: Ratio of 84th Percentile for Construction Workers in Specified Work Areas 

over 84th Percentile for Non-Construction Workers in All Work Areas ...............41 

Table 4-4: Ratio of GSD for Construction Workers in Specified Work Areas over GSD 

for Non-Construction Workers in All Work Areas................................................42 

Table 4-5: Ratio of 84th Percentile for Construction Workers in Specified Work Areas 

over 84th Percentile for Construction Workers in All Work Areas........................47 

Table 4-6: Ratio of GSD for Construction Workers in Specified Work Areas over GSD 

for Construction Workers in All Work Areas........................................................47 

Table 5-1: Ratio of 84th Percentile of Tritium Samples from Construction Workers 

in Specified Craft over 84th Percentile of Tritium Samples from 

Construction Workers in All Crafts .......................................................................51 

Table 5-2: Ratio of GSD of Tritium Samples from Construction Workers in Specified 

Craft over GSD of Tritium Samples from Construction Workers in All 

Crafts......................................................................................................................52 

Table 5-3: Ratio of 84th Percentile of Tritium Samples from Construction Workers in 

Specified Crafts over 84th Percentile of Tritium Samples from 

All Non-Construction Workers..............................................................................53 

Table 5-4: Ratio of GSD of Tritium Samples from Construction Workers in Specified 

Crafts over GSD of Tritium Samples from All Non-Construction Workers.........54 
SRS – Draft Review of OTIB-0075 4 SC&A – January 13, 2010 

NOTICE: This report has been reviewed for Privacy Act information and has been cleared for distribution. 

However, this report is pre-decisional and has not been reviewed by the Advisory Board on Radiation and Worker 

Health for factual accuracy or applicability within the requirements of 42 CFR 82. 

LIST OF FIGURES 

Figure 2-1: Mean Uranium Concentrations in Urine at Y-12 for 

Claimant and Complete Datasets...........................................................................16 

Figure 2-2: Comparison of Mean Uranium Concentrations at Y-12 (1950 to 1988) ...............17 

Figure 2-3: Standard Deviation of Uranium Concentrations in Urine at Y-12 for 

Claimant and Complete Datasets...........................................................................18 

Figure 2-4: Comparison of Standard Deviation of Uranium Concentrations at Y-12 

(1950 to 1988)........................................................................................................19 

Figure 2-5: Mean Plutonium Concentrations in Urine at Mound for Claimant and 

Complete Datasets .................................................................................................21 

Figure 2-6: Comparison of Mean Plutonium Concentrations at Mound (1960 to 1990) .........22 

Figure 2-7: Standard Deviation of Plutonium Concentrations in Urine at Mound for 

Claimant and Complete Datasets...........................................................................22 

Figure 2-8: Comparison of Standard Deviation of Plutonium Concentrations at Mound 

(1960 to 1990)........................................................................................................23 

Figure 2-9: Mean Annual Tritium Dose at SRS for Claimant and Complete Datasets............25 

Figure 2-10: Comparison of Mean Annual Tritium Dose at SRS (1991 to 2001)......................26 

Figure 2-11: Standard Deviation of Annual Tritium Dose at SRS for 

Claimant and Complete Datasets...........................................................................27 

Figure 2-12: Comparison of Standard Deviation of Annual Tritium Dose at SRS 

(1991 to 2001)........................................................................................................27 

Figure 2-13: Comparison of Mean Annual Tritium Dose at SRS (1992 to 2001)......................28 

Figure 4-1: Ratio of 84th Percentile of Tritium Samples from Non-Construction 

Workers (NCW) in Specified Work Areas over 84th Percentile of Tritium 

Samples from Non-Construction Workers in All Work Areas, by Decade...........35 

Figure 4-2: Ratio of GSD of Tritium Samples from Non-Construction Workers (NCW) 

in Specified Work Areas over GSD of Tritium Samples from NonConstruction Workers in All Work Areas, by Decade ..........................................36 

Figure 4-3: Ratio of 84th Percentile of Plutonium Samples from Non-Construction 

Workers (NCW) in Specified Work Areas over 84th Percentile of Plutonium 

Samples from Non-Construction Workers in All Work Areas, by Decade...........37 

Figure 4-4: Ratio of GSD of Plutonium Samples from Non-Construction Workers 

(NCW) in Specified Work Areas over GSD of Plutonium Samples from 

Non-Construction Workers in All Work Areas, by Decade ..................................38 

Figure 4-5: Ratio of 84th Percentile of Uranium Samples from Non-Construction 

Workers (NCW) in Specified Work Areas over 84th Percentile of Uranium 

Samples from Non-Construction Workers in All Work Areas, by Decade...........39 

Figure 4-6: Ratio of GSD of Uranium Samples from Non-Construction Workers 

(NCW) in Specified Work Areas over GSD of Uranium Samples from NonConstruction Workers in All Work Areas, by Decade ..........................................39 
SRS – Draft Review of OTIB-0075 5 SC&A – January 13, 2010 

NOTICE: This report has been reviewed for Privacy Act information and has been cleared for distribution. 

However, this report is pre-decisional and has not been reviewed by the Advisory Board on Radiation and Worker 

Health for factual accuracy or applicability within the requirements of 42 CFR 82. 

Figure 4-7: Ratio of 84th Percentile of Tritium Samples from Construction Workers 

(CW) in Specified Work Areas over 84th Percentile of Tritium Samples 

from Non-Construction Workers (NCW) in All Work Areas, by Decade ............42 

Figure 4-8: Ratio of GSD of Tritium Samples from Construction Workers (CW) in 

Specified Work Areas over GSD of Tritium Samples from NonConstruction Workers (NCW) in All Work Areas, by Decade .............................43 

Figure 4-9: Ratio of 84th Percentile of Plutonium Samples from Construction Workers 

(CW) in Specified Work Areas over 84th Percentile of Plutonium Samples 

from Non-Construction Workers (NCW) in All Work Areas, by Decade ............43 

Figure 4-10: Ratio of GSD of Plutonium Samples from Construction Workers (CW) in 

Specified Work Areas over GSD of Plutonium Samples from NonConstruction Workers (NCW) in All Work Areas, by Decade .............................44 

Figure 4-11: Ratio of 84th Percentile of Uranium Samples from Construction Workers 

(CW) in Specified Work Areas over 84th Percentile of Uranium Samples 

from Non-Construction Workers (NCW) in All Work Areas, by Decade ............44 

Figure 4-12: Ratio of GSD of Uranium Samples from Construction Workers (CW) in 

Specified Work Areas over GSD of Uranium Samples from NonConstruction Workers (NCW) in All Work Areas, by Decade .............................45 

Figure 4-13: Ratio of 84th Percentile of Tritium Samples from Construction Workers 

(CW) in Specified Work Areas over 84th Percentile of Tritium Samples 

from Construction Workers in All Work Areas, by Decade..................................48 

Figure 4-14: Ratio of GSD of Tritium Samples from Construction Workers (CW) in 

Specified Work Areas over GSD of Tritium Samples from Construction 

Workers in All Work Areas, by Decade ................................................................48 

Figure 4-15: Ratio of 84th Percentile of Plutonium Samples from Construction Workers 

(CW) in Specified Work Areas over 84th Percentile of Plutonium Samples 

from Construction Workers in All Work Areas, by Decade..................................49 

Figure 4-16: Ratio of GSD of Plutonium Samples from Construction Workers (CW) in 

Specified Work Areas over GSD of Plutonium Samples from Construction 

Workers in All Work Areas, by Decade ................................................................49 

Figure 4-17: Ratio of 84th Percentile of Uranium Samples from Construction Workers 

(CW) in Specified Work Areas over 84th Percentile of Uranium Samples 

from Construction Workers in All Work Areas, by Decade..................................50 

Figure 4-18: Ratio of GSD of Uranium Samples from Construction Workers (CW) in 

Specified Work Areas over GSD of Uranium Samples from Construction 

Workers in All Work Areas, by Decade ................................................................50 

Figure 5-1: Ratio of 84th Percentile of Tritium Samples from Construction Workers in 

Specified Crafts over 84th Percentile of Tritium Samples from Construction 

Workers in All Construction Crafts, by Decade ....................................................51 

Figure 5-2: Ratio of GSD of Tritium Samples from Construction Workers in Specified 

Crafts over GSD of Tritium Samples from Construction Workers in All 

Construction Crafts, by Decade .............................................................................52 
SRS – Draft Review of OTIB-0075 6 SC&A – January 13, 2010 

 This report has been reviewed for Privacy Act information and has been cleared for distribution. 

However, this report is pre-decisional and has not been reviewed by the Advisory Board on Radiation and Worker 

Health for factual accuracy or applicability within the requirements of 42 CFR 82. 

NOTICE:

Figure 5-3: Ratio of 84th Percentile of Tritium Samples from Construction Workers in 

Specified Crafts over 84th Percentile of Tritium Samples from All NonConstruction Workers, by Decade .........................................................................53 

Figure 5-4: Ratio of GSD of Tritium Samples from Construction Workers in Specified 

Crafts over GSD of Tritium Samples from All Non-Construction Workers, 

by Decade...............................................................................................................54 
SRS – Draft Review of OTIB-0075 7 SC&A – January 13, 2010 

NOTICE: This report has been reviewed for Privacy Act information and has been cleared for distribution. 

However, this report is pre-decisional and has not been reviewed by the Advisory Board on Radiation and Worker 

Health for factual accuracy or applicability within the requirements of 42 CFR 82. 

1.0 INTRODUCTION AND SUMMARY OF FINDINGS 

The Advisory Board on Radiation and Worker Health (ABRWH) has asked SC&A to perform a 

review of the Special Exposure Cohort petition (SEC-00103) for construction workers at 

Savannah River Site (SRS) and NIOSH’s Evaluation Report (NIOSH 2008). SC&A has 

prepared a draft matrix of issues related to this SEC (SC&A 2009). The present report is a 

focused analysis that relates to issue number 16 in that matrix. This issue states that the use of 

all claimant data for building a coworker model for SRS construction workers is questionable. 

NIOSH’s statement regarding an internal dose coworker model in its Evaluation Report is as 

follows: 

The majority of SRS workers was monitored for internal intake of radionuclides 

and has internal monitoring data. This point is reflected in the NOCTS claimant 

files for which 1467 of the 1798 construction worker claim files contained 

internal monitoring data. However, the possibility exists that some workers who 

should have been monitored were not, or that the data for some workers who 

were monitored has been misplaced. As a result, NIOSH is developing a coworker model based on the claimant data in NOCTS. There are approximately 

382,000 in vitro bioassay records available for analysis in NOCTS. A separate 

study has been completed that established the principle that, under certain 

conditions, the data in NOCTS are representative of a site’s population 

generally (ORAUT-OTIB-0075). All of the SRS NOCTS data has been entered 

into a database, and the co-worker model is in preparation. In addition, 

ORAUT-OTIB-0052 indicated that construction trades workers had more 

plutonium bioassay measurements below the reporting limit compared with nonconstruction workers. ORAUT-OTIB-0052 also found that for the positive 

bioassays, the non-construction workers results were generally higher than 

construction trades workers. [NIOSH 2008, p. 39] [Emphasis added.] 

The present focused review relates to the two sentences that that we have indicated in bold. The 

NIOSH justification for this approach depends on two hypotheses that are implicitly connected 

in the above paragraph in the bolded sentences that follow each other: 

(1) Claimant data are representative of the entire worker population. 

(2) Given Item 1 above, a coworker model can be developed from SRS claimant data that 

will satisfy the requirements of 42 CFR 83 for dose reconstruction with sufficient 

accuracy for SRS construction workers during the requested SEC period from January 1, 

1950, to December 31, 2007. 

NIOSH has addressed the issue of the representativeness of claimant data for the entire worker 

population in Use of Claimant Datasets for Coworker Modeling, ORAUT-OTIB-0075, Rev. 00, 

May 5, 2009, cited hereafter as OTIB-0075. This review evaluates OTIB-0075 in the specific 

context of the SEC Petition for SRS, SEC-00103. This requires evaluating both of the 
SRS – Draft Review of OTIB-0075 8 SC&A – January 13, 2010 

NOTICE: This report has been reviewed for Privacy Act information and has been cleared for distribution. 

However, this report is pre-decisional and has not been reviewed by the Advisory Board on Radiation and Worker 

Health for factual accuracy or applicability within the requirements of 42 CFR 82. 

hypotheses that NIOSH has made above. An important consideration in the second hypothesis is 

whether it applies to all types of construction workers in the various different phases of SRS 

operation. A critical link, which NIOSH has not made explicit, also needs to be addressed. Are 

the claimant data adequate to ensure a bounding dose estimate or a dose estimate more precise 

than that (i.e., dose reconstruction with sufficient accuracy) for all members of the proposed 

class, including those who were not monitored at all, or those who were not monitored for certain 

radionuclides or in certain periods? 

It should be noted that NIOSH has not yet published the SRS coworker model based on claimant 

data that it proposes to use for SRS construction workers to demonstrate dose reconstruction with 

sufficient accuracy for all members of the proposed class. Hence, this report analyzes whether 

NIOSH’s approach appears to be equal to the task of creating a coworker model, or whether 

additional data and elements are needed so far as the two hypotheses above are concerned. 

In view of the above, this review of the study conducted by NIOSH to support their proposal 

addresses two separate but related questions: 

(1) Is a large (site-wide, but non-random) collection of available data from SRS claimants 

who were monitored in a given year representative of other large (site-wide and random) 

samples drawn from nearly complete coworker populations?

OTIB-0075 compared the lognormal parameters estimated from a large sample of 

claimants in a given year with the parameters estimated from similar-sized samples of 

data from all workers on the site in that year. Attachments C, F, and I of OTIB-0075 

contain a large number of scatter plots of the values of the lognormal distribution 

parameters obtained from the claimant dataset and from 1,000 independent samples of 

similar size drawn from the larger all-worker dataset at Y-12, Mound Laboratory, and 

SRS. According to NIOSH, 

These plots are presented to support the idea that the claimant dataset is 

basically no different than a random draw from the complete dataset (p.1, 

Attachments C, F, and I to OTIB-0075). 

While the plots demonstrate that similar parameter estimates are obtained from the 

claimant dataset and the all-worker dataset samples, there is no formal statistical test of 

this apparent similarity with an assigned level of confidence. This core finding of OTIB0075 is a statement of the law of large numbers. Given a sufficiently large sample size, 

estimates of population parameters will, on average, converge to the true values. The 

results of OTIB-0075 demonstrate that the parameter estimates are not very different. 

However, this SC&A analysis shows that this result does not confirm the adequacy of the 

proposed approach for the purpose of dose reconstruction of each individual claimant for 

the reasons presented below. 

OTIB-0075 is based on the few complete datasets that are available in electronic form for 

all coworkers at three sites; uranium urine bioassay from workers at the Y-12 Plant for 
SRS – Draft Review of OTIB-0075 9 SC&A – January 13, 2010 

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Health for factual accuracy or applicability within the requirements of 42 CFR 82. 

1950 to 1988, plutonium urine bioassay at the Mound Laboratory for 1960 to 1990, and 

tritium data at SRS for 1991 to 2001. To amass a sufficiently large dataset for their 

purpose, NIOSH found it was necessary to aggregate the available claimant data for the 

entire site at an annual level. Use of this high degree of aggregation was necessary, 

because sufficient amounts of claimant data were presumably not available to support an 

analysis with detail, for example, by work area on the site or by job type. 

Implicit in the NIOSH approach is the assumption that no further detail in the estimates is 

required for estimating missed doses of workers. This is a one-size-fits-all approach that 

ignores important differences among claimants who worked in different areas of the site 

doing different jobs. No detail by work area is provided in OTIB-0075, although a 

detailed examination by work area would be the next logical step in this type of analysis. 

It is not likely that the same conclusions would be demonstrated if the variety of work 

areas at SRS were analyzed individually. SC&A recognizes that collecting coworker 

data at this level of granularity might be difficult, because the amount of claimant data 

available in each work area in each year would be much smaller than the sample sizes 

used by NIOSH in their study of aggregated data for the entire site. Nevertheless, our 

analysis shows that such a level of granularity is needed. 

(2) Is the procedure proposed by NIOSH applicable to the SEC-00103 for the SRS 

construction worker claimants? 

Implicit in the NIOSH approach is the assumption that their proposal is applicable to all 

SRS claimants, including those in the construction crafts addressed in SEC-00103. In 

this approach, construction worker claimants with missed data in a given year would be 

assigned doses estimated from exposure data from all SRS claimants in that year, 

regardless of the occupation of the claimant. Estimates of missed doses for construction 

workers should be based on coworker data that are representative of construction 

workers. The NIOSH approach cannot be used if the claimant data are limited to 

claimants who were construction workers, due to the small number of construction 

worker claimants in each year. If NIOSH plans to use non-construction worker data for 

developing a coworker model for construction workers, they will need to demonstrate 

that the potential for internal exposure of non-construction workers is comparable or 

greater than that for all construction workers who are part of the proposed SEC class. As 

described below, the limited electronic data for non-construction workers appear to 

indicate that construction workers might have experienced higher internal exposures than 

non-construction workers in many cases. 

This critical issue, not mentioned in the proposal by NIOSH, is addressed in this review 

through a detailed analysis of claimant data for construction and non-construction 

workers by job type, work area, and time period. Note that our analysis of this issue is 

limited by the same factors that limited NIOSH; only claimant data were available for 

this analysis. A more thorough analysis would be based on the complete coworker 

dataset. The small sample sizes that result when the claimant data are used in this 

detailed fashion demonstrate the inadequacy of the proposed approach to address detailed 

analyses. The findings of our analysis of claimant data show that there are important 
SRS – Draft Review of OTIB-0075 10 SC&A – January 13, 2010 

NOTICE: This report has been reviewed for Privacy Act information and has been cleared for distribution. 

However, this report is pre-decisional and has not been reviewed by the Advisory Board on Radiation and Worker 

Health for factual accuracy or applicability within the requirements of 42 CFR 82. 

differences in exposure between construction workers and non-construction workers, and 

construction workers have different exposures than non-construction workers in many 

SRS work areas and time periods. Important differences in exposure are also evident 

when the claimant data for construction workers in each of the construction crafts are 

examined. 

This report contains a brief general review of the OTIB-0075 analysis prepared by NIOSH, and 

further analyses to address the significance of OTIB-0075 for construction workers at SRS. 

OTIB-0075 examined internal exposure data at three sites; uranium at the Y-12 Plant from 1950 

to 1988, plutonium at the Mound Laboratory from 1960 to 1990, and tritium at SRS from 1991 

to 2001. The study reports comparisons of aggregate site-wide exposure by year for all types of 

workers at these facilities. The results of the OTIB-0075 study indicate that the annual 

distributions of site-wide exposures for claimants are similar to the annual distributions derived 

from similarly sized samples of site-wide exposures for all workers within the expected degree of 

statistical variation. 

1.1 FINDINGS WITH SUMMARY OF ANALYSIS 

1.1.1 Y-12 Claimants and All-Worker Uranium Data 

This review begins with a comparison of the mean and standard deviations of the lognormal 

distributions derived for the claimant and complete (all-worker) uranium biosamples at the Y-12 

Plant (OTIB-0075, Table 4-1). The means and standard deviations of the lognormal distributions 

in each year from 1950 to 1988 were compared using a linear regression model. Conclusions 

were based on hypothesis tests (t-tests) for the value of the regression coefficients. The 

hypothesis tests confirmed similarity of the estimated claimant and all-worker means and 

standard deviations at Y-12. 

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. 

1.1.2 Mound Claimant and All-Worker Data 

A similar comparison of the means and standard deviations of the lognormal distributions for the 

claimant and complete datasets for plutonium at Mound Laboratory (OTIB-0075, Table 6-2) was 

conducted using the regression model and hypothesis tests. At Mound, the comparisons for the 

mean and standard deviation do not show good agreement between the two datasets. The 

estimated regression line indicates that the mean for the all-worker dataset is much higher than 

the mean for the claimant dataset in the years when exposures are the highest. A coworker 

model based on claimant-only data would tend to underestimate typical exposures in years when 

exposures were high. 

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 
SRS – Draft Review of OTIB-0075 11 SC&A – January 13, 2010 

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However, this report is pre-decisional and has not been reviewed by the Advisory Board on Radiation and Worker 

Health for factual accuracy or applicability within the requirements of 42 CFR 82. 

aggregation. This finding raises questions concerning the conclusions reached in OTIB-0075 

for plutonium at the Mound Laboratory. 

1.1.3 SRS Claimant and All-Worker Data, Tritium 

At SRS, there are approximately 10,000 workers in the all-worker tritium dataset and 451 

claimants. The lognormal distributions derived from the claimant and all-worker datasets for 

tritium at SRS cover only 11 years (OTIB-0075, Table 7-2). The regression results for all years 

from 1991 to 2001 are dominated by a single year with high exposure, 1991. When this year is 

omitted, the regressions shows no unduly influential data values from 1992 to 2001, and the 

complete and claimant datasets for annual tritium doses during this period show no significant 

difference at the annual level of aggregation. 

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. 

1.1.4 SRS Data for Radionuclides Other than Tritium in ORAUT-OTIB-0075 

The comparisons for the three sites above were based on the use of site-wide data for estimating 

both the claimant and all-worker exposure distributions. With respect to SRS, OTIB-0075 had 

access to data on only tritium in the later years of operations at the site after many of the 

production and processing facilities, such as nearly all production reactors, had ceased operation. 

Note that the production reactors were the facilities in which the SRS tritium was created. 

FINDING #4: At SRS, OTIB-0075 includes data only for tritium from 1991 to 2001 in 

comparing the claimant population to that of all workers. No analysis of uranium or 

plutonium exposures at SRS was possible, because the available hardcopy data have not been 

reduced to electronic form. Similarly, no analysis of uranium or fission product exposures 

regarding the validity of the central hypothesis of OTIB-0075 for SRS could be done for any 

period. No analysis of tritium exposures before 1991 was done for the same reason. 

Furthermore, the tritium conclusion cannot be back-extrapolated in time, since the production 

and work conditions relating to tritium were different in earlier periods. 

1.1.5 Proposed SRS Data Aggregation for All Claimants 

In terms of representativeness, NIOSH has provided no justification that the use of site-wide 

datasets in the construction of a coworker model for SRS is representative of individual claimant 

exposures at large sites like SRS, with its long history of different activities in the variety of 

facilities on the site. In OTIB-0075, the tritium data for all claimants were treated as if they were 

all drawn from the same distribution, without regard to area or job type, or whether nonconstruction workers who constitute the bulk of the claimants are representative of construction 
SRS – Draft Review of OTIB-0075 12 SC&A – January 13, 2010 

NOTICE: This report has been reviewed for Privacy Act information and has been cleared for distribution. 

However, this report is pre-decisional and has not been reviewed by the Advisory Board on Radiation and Worker 

Health for factual accuracy or applicability within the requirements of 42 CFR 82. 

workers in terms of tritium intakes. There is also no analysis showing that any conclusions for 

tritium are valid for other radionuclides. 

FINDING #5: Data for the entire SRS were aggregated by year for the NIOSH analysis, with 

no detail by work area or by job type. The proposed NIOSH coworker model for SRS 

construction workers includes no analysis of these details. 

1.1.6 Completeness of Y-12 Uranium Data used in ORAUT-OTIB-0075 

In terms of representativeness, NIOSH has described the all-worker dataset as “complete.” This 

term means only that NIOSH has used all the worker data that were available for the years 

covered. The dataset is not “complete” in the sense that it covers all workers. There were many 

workers at these sites who were not monitored, and many more workers who were infrequently 

monitored. OTIB-0075 (p. 10, footnote 7) states, “Out of 1,971 total claimants for Y-12, 731 

have uranium urine bioassay results in the complete dataset and 1,240 do not (presumably 

because they were not monitored).” 

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.

1.1.7 Y-12 Data Aggregation in the Coworker Model 

Despite the lack of completeness, the all-worker uranium database at Y-12 is very large and 

covers almost 40 years of operations. Of the three sites examined, Y-12 has the most extensive 

all-worker dataset. Despite the large size of the all-worker and claimant datasets that were 

available for the uranium study at Y-12, NIOSH did not provide any detailed comparisons of the 

claimant and all-worker data by job type or by area of the site in OTIB-0075. 

FINDING #7: Data for the entire Y-12 site were aggregated by year for the NIOSH analysis, 

with no detail by work area or by job type. The NIOSH approach includes no analysis of these 

details. 

1.1.8 Aggregation of Mound Data 

At Mound, the study period covers 30 years of operations, but the plutonium datasets used for 

the OTIB-0075 analysis are much smaller than at Y-12. The database contains 2,070 workers 

who submitted a total of 53,340 plutonium urine bioassay samples. The 225 claimants with 

bioassay data submitted 8,849 plutonium urine samples. Despite the relatively large size of the 

datasets available for comparison at Mound Laboratory, no details are provided by job type or by 

area of the site. 

FINDING #8: Data for the entire Mound Laboratory were aggregated by year for the NIOSH 

analysis, with no detail by work area or by job type. The NIOSH approach includes no 

attention to these details. 
SRS – Draft Review of OTIB-0075 13 SC&A – January 13, 2010 

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However, this report is pre-decisional and has not been reviewed by the Advisory Board on Radiation and Worker 

Health for factual accuracy or applicability within the requirements of 42 CFR 82. 

1.1.9 Findings Specific to SRS 

NIOSH’s Evaluation Report for SEC-00103 indicates that, according to the analysis in OTIB0075, “the data in NOCTS are representative of a site’s population,” and thus the NOCTS data 

will be used as the technical bases of the coworker model for SRS, including a coworker model 

for SRS construction workers (NIOSH 2008, pp. 70 and 72). However, the above analyses are 

not based on a comparison of construction worker claimants to non-construction worker 

claimants. In effect, OTIB-0075 does not have any analyses that would establish the validity of 

the hypothesis that all claimant data at any site, including SRS, are representative of construction 

worker data for that site for various periods and radionuclides. Furthermore, OTIB-0075 does 

not have any analysis that establishes that using all-worker or all-claimant data for particular job 

types and areas will result in a dose reconstruction that meets the requirements of sufficient 

accuracy under 42 CFR 83. The OTIB-0075 study provides only general analyses of all workers 

by year, with no differentiation by job type. In addition, the OTIB-0075 study only looked at 

tritium in the most recent years of operations at SRS. 

To address these concerns, the remainder of this review contains an analysis of SRS claimant 

exposures by work area and job type. Due to the lack of all-worker data in electronic form at 

SRS, this review could only look at claimant exposures. We must proceed under an assumption 

that the NOCTS data are representative of all workers at SRS, even though OTIB-0075 only 

performed a limited test for tritium for the 1991–2001 period. 

This review of claimant exposures addresses both non-construction worker claimants and 

construction worker claimants. The advantages of using claimant data for this portion of the 

analysis are that the job types and work areas are known for many of the claimants, and the data 

cover all decades of operation at SRS. The review examined five different sources of exposure; 

tritium, plutonium, uranium, enriched uranium, and fission products. 

This review contains three sets of analyses by area of the site: 

(1) A comparison by decade of exposures of non-construction workers by SRS work area to 

all non-construction worker data in NOCTS 

(2) A comparison by SRS work area of construction worker exposures to all nonconstruction workers in NOCTS 

(3) A comparison of construction worker exposures by SRS work area to all construction 

workers in the NOCTS database 

In the first set of analyses by work area, non-construction worker claimant exposures are 

compared by decade with aggregated exposures over all work areas. A ratio equal to the 84th

percentile for each work area divided by the 84th percentile for all work areas is used in this 

comparison. A similar ratio of the geometric standard deviations (GSD) was also calculated. 

The purpose of this comparison is to demonstrate that non-construction workers in different 

work areas have different levels of exposures. If large differences in the 84th percentile or GSD 

are found by work area, then the NIOSH coworker model, which assigns exposures estimated 
SRS – Draft Review of OTIB-0075 14 SC&A – January 13, 2010 

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from aggregate claimant data for all work areas combined, would not be claimant favorable for 

claimants in some specific work areas. 

FINDING #9: At SRS, the 84th percentile of exposures to tritium, plutonium, uranium, and 

other radionuclides for non-construction workers in specific work areas show considerable 

differences from the 84th percentile of exposures to non-construction workers site-wide. 

Similar results are observed for the corresponding ratio of the GSDs. 

The second set of analyses by area provides a comparison of construction worker exposures by 

work area of the site with non-construction worker exposures aggregated over all work areas. A 

ratio equal to the 84th percentile for construction worker claimants in each work area divided by 

the 84th percentile for data from non-construction workers in all work areas is used in this 

comparison. A similar ratio of the GSDs was also calculated. The purpose of this comparison is 

to demonstrate that the NIOSH proposal to use non-construction worker claimant data from all 

work areas for estimating missed doses to construction workers will underestimate the dose for 

some construction worker claimants and overestimate the dose to other construction worker 

claimants, in some cases by considerable amounts, for instance by a factor of two or more. If 

large differences in the 84th percentile or GSD are found, then assigning non-construction worker 

claimant data in the coworker model to construction workers, as proposed by NIOSH, would not 

be claimant favorable for some work areas and periods. 

FINDING #10: At SRS, the 84th percentile of exposures to tritium, plutonium, and other 

radionuclides for construction workers in specific work areas show considerable differences 

from the 84th percentile of exposures to all construction workers site-wide. Similar results are 

observed for the corresponding ratio of the GSDs. 

The third set of analyses by area contains comparisons of construction worker exposures by work 

area with construction worker exposures aggregated over all work areas. A ratio equal to the 84th

percentile for construction worker claimants in each work area divided by the 84th percentile for 

construction workers in all work areas is used in this comparison. A similar ratio of the GSDs 

was also calculated. The purpose of this comparison is to show that sizeable differences occur 

between work areas for construction worker claimants. It should be noted that data for 

construction worker exposure to uranium, enriched uranium, and fission products are very 

sparse, preventing the calculation of ratios in many decades. In general, the discrepancies for 

tritium and plutonium are found to be larger than those observed in the comparison for nonconstruction workers by work area, as discussed above in the first set of analyses. 

FINDING #11: At SRS, the 84th percentile of exposures to tritium and plutonium for 

construction workers in specific work areas show large differences from the 84th percentile of 

site-wide exposures to construction workers. Similar results are observed for the 

corresponding ratio of the GSDs. In many cases, there are insufficient data for construction 

workers to make a comparison for uranium, enriched uranium, and fission products. 

The review ends with two analyses of SRS construction worker claimant exposures for tritium by 

construction craft. A ratio equal to the 84th percentile for construction worker claimants in each 

craft divided by the 84th percentile for construction workers in all construction crafts is used in 
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the first analysis. A similar ratio of the GSD was also calculated. This comparison provides a 

measure of the differences in exposure among construction workers in different crafts for the 

SRS radionuclide studied by NIOSH in OTIB-0075. 

FINDING #12: At SRS, the 84th percentile of exposures to tritium for construction workers in 

specific crafts shows large differences from the 84th percentile of exposures to all construction 

workers. Similar results are observed for the corresponding ratio of the GSDs. 

In the second analysis by construction craft, a ratio equal to the 84th percentile for construction 

worker claimants in each craft divided by the 84th percentile for all non-construction workers is 

used. A similar ratio of the GSD was also calculated. This ratio measures how well site-wide 

non-construction worker data perform when estimating construction worker exposures in 

different crafts. This ratio is affected both by the differences in exposure among the construction 

crafts and the differences between construction workers and non-construction workers. Only 

tritium was examined in the comparisons by construction craft, due to lack of sufficient data for 

other nuclides. 

FINDING #13: At SRS, the 84th percentile of exposures to tritium for construction workers in 

specific crafts shows large differences from the 84th percentile of site-wide exposures for nonconstruction workers. Similar results are observed for the corresponding ratio of the GSDs. 

2.0 REVIEW OF THE STUDY CONDUCTED BY NIOSH 

To verify the representativeness of using available data from claimants in lieu of actual coworker 

data (i.e., data sorted by specific job category, location, and time period), NIOSH looked at three 

cases where essentially complete coworker datasets were available in electronic form: 

Y-12 Plant Uranium urine bioassay 1950–1988 

Mound Laboratory Plutonium urine bioassay 1960–1990 

Savannah River Site (SRS) Tritium dose 1991–2001 

2.1 COMPARISON OF CLAIMANT AND COMPLETE DATASETS FOR URANIUM 

AT THE Y-12 PLANT 

NIOSH presents a summary of the results of their study of the annual uranium in urine samples 

at the Y-12 Plant in Table 4-1 of OTIB-0075. The table contains the lognormal distribution 

parameters estimated for the claimant and complete (all-worker) datasets in each year from 1950 

to 1988. To obtain these estimates, all samples were combined into a single dataset for each 

year, with no differentiation by work area or job type. 

Figure 2-1 displays a time series plot comparing the mean uranium concentrations in urine for 

each dataset. The arithmetic mean (expected value) and standard deviation of the lognormal 

distributions were calculated from the parameter values shown in Table 4-1 of ORAUT-0075 

using the standard formulas (Battelle 2007, Table 2.2). The mean of the lognormal distribution 

is used in this review to compare the expected values of the two distributions. The expected 
values are approximately twice as high as the median concentrations shown in Figure 4-3 of 

OTIB-0075, and slightly lower than the 84th percentiles shown in Figure 4-4 of OTIB-0075. The 

claimant dataset has a lower mean in the earliest and latest years, and a higher mean in 1984. 

The outlier in 1984 is also obvious in the figure on page 18 of Appendix C to OTIB-0075. 

Examination of the regression plot in the figure on page 18 of Appendix B to OTIB-0075 shows 

that this high slope appears to overestimate the exposures in the upper tail of the distribution of 

claimant samples in this year. 

A scatter plot of the mean uranium concentrations for the claimant versus the complete datasets 

is shown in Figure 2-2. Each year appears as a single point in this figure, with the complete (allworker) annual mean plotted on the horizontal axis and the claimant annual mean plotted on the 

vertical axis. The dashed line in the figure at 45 degrees is the line of perfect equality. Data 

points falling on this line have equal values for the complete and claimant means. The solid line 

in the figure is the best-fitting regression line for the plotted data points. The estimated slope and 

y-intercept of the regression line may be compared to the ideal values of 1 and 0, respectively, 

using a hypothesis test derived from the regression statistics. The hypothesis test is based on the 

standard error of estimation of the slope and intercept. The hypothesis is rejected when the 

probability level (p-level) for the test is less than 0.05, meaning that there is less than a 5% 

chance that the intercept or slope would differ by this much or more from its target value of 0 or 

1, respectively, due to the magnitude of the error in its estimation. The results of the hypotheses 

tests are shown in the upper portion of Table 2-1. The hypotheses that the intercept is 0 and the 

slope is 1 are accepted for the mean of the uranium samples at Y-12. 

SRS – Draft Review of OTIB-0075 16 SC&A – January 13, 2010 

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Figure 2-1: Mean Uranium Concentrations in Urine at Y-12 for 

Claimant and Complete Datasets 

Mean Uranium Concentrations in Urine at Y-12 

for Claimant and Complete Datasets

0

5

10

15

20

25

30

35

40

45

1950 1960 1970 1980 1990

Uranium in Urine (dpm/day)

Complete Dataset (All Workers) Claimant Dataset
Comparison of Mean Uranium Concentrations at Y-12

(1950 to 1988)

y = 0.920x + 0.456

R2

 = 0.672

0

10

20

30

40

50

0 10 20 30 40 50

Complete Mean (dpm/day)

Claimant Mean (dpm/day)

Figure 2-2: Comparison of Mean Uranium Concentrations at Y-12 (1950 to 1988) 

Table 2-1: Summary of Regression Comparisons of Complete (All-Worker) and 

Claimant-Only Distributions for Uranium at the Y-12 Plant 

Years n 

Lognormal 

Distribution 

Parameter 

Regression 

Coefficient 

Estimated 

Coefficient

Standard 

Error of 

Estimate 

Hypothesis 

Tested 

t-statistic 

for Test 

p-level 

Pr{|X|>|t|}

Hypothesis 

Test 

Result 

1950 39 Mean Intercept 0.456 2.245 Intercept=0? 0.203 0.840 Accept 

to Slope 0.920 0.106 Slope=1? -0.757 0.454 Accept 

1988 R2 0.672 

 

Standard 

Deviation Intercept 8.822 14.697 Intercept=0? 0.600 0.552 Accept 

 Slope 0.826 0.243 Slope=1? -0.717 0.478 Accept 

 R2 0.238 

Figure 2-3 shows a time series plot comparing the standard deviation of the lognormal 

distributions in each year for each dataset. The claimant dataset also has a lower standard 

deviation in the earliest and latest years, and a higher standard deviation in the outlier year 1984. 

A scatter plot of the standard deviation of the uranium concentrations for the claimant versus the 

complete datasets is shown in Figure 2-4. The estimated value for the slope and y-intercept of 

the regression line in this figure and the standard error of each estimate for uranium at Y-12 are 

shown in the lower part of Table 2-1. The estimated slope and y-intercept of the regression line 

are compared to the ideal values of 1 and 0, respectively, using the t-test. The results of these 

SRS – Draft Review of OTIB-0075 17 SC&A – January 13, 2010 

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hypotheses tests are shown in Table 2-1. The hypotheses that the intercept is 0 and the slope is 1 

are accepted for the standard deviation of uranium samples at Y-12. The conclusion is that the 

complete (all-worker) and claimant datasets for uranium in urine at the Y-12 Plant show no 

significant statistical differences at the annual level of aggregation; samples from all work areas 

and all job types are combined. 

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. 

Complete Dataset (All Workers) Claimant Dataset

Uranium in Urine (dpm/day)

1950 1960 1970 1980 1990

250

200

150

100

50

0

Standard Deviation of Uranium Concentrations in Urine at Y-12 

for Claimant and Complete Datasets

Figure 2-3: Standard Deviation of Uranium Concentrations in Urine at Y-12 for 

Claimant and Complete Datasets 

SRS – Draft Review of OTIB-0075 18 SC&A – January 13, 2010 

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Comparison of Standard Deviation of Uranium

Concentrations at Y-12

(1950 to 1988)

y = 0.826x + 8.822

R2

 = 0.238

0

25

50

75

100

125

150

175

200

225

0 25 50 75 100 125 150 175 200 225

Complete Standard Deviation (dpm/day)

Claimant Standard Deviation (dpm/day)

Figure 2-4: Comparison of Standard Deviation of Uranium Concentrations at Y-12 

(1950 to 1988) 

2.2 COMPARISON OF CLAIMANT AND COMPLETE DATASETS FOR 

PLUTONIUM AT MOUND LABORATORY 

NIOSH presents a summary of the results of their study of the annual plutonium in urine samples 

at the Mound Laboratory in Table 6-2 of OTIB-0075. The table shows the lognormal 

distribution parameters estimated for the claimant and complete (all-worker) datasets in each 

year from 1960 to 1990. All samples were combined into a single dataset for each year, with no 

differentiation by work area or job type. Figure 2-5 shows a time series plot comparing the mean 

plutonium concentrations in urine for each dataset. The claimant dataset has a lower mean in the 

early years and a higher mean in the last 6 years. The claimant dataset underestimates the 

expected exposure of the average worker from 1960 to 1964, and overestimates exposures after 

1984. 

A scatter plot of the mean plutonium concentrations for the claimant versus the complete datasets 

is shown in Figure 2-6. The dashed line in the figure at 45 degrees is the line of perfect equality. 

At Mound, the estimated regression line lies far below the line of perfect equality, indicating that 

the mean for the complete dataset is much higher than the mean for the claimant dataset in the 

years when exposures are the highest. 

SRS – Draft Review of OTIB-0075 19 SC&A – January 13, 2010 

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Figure 2-7 shows a time series plot comparing the standard deviation of the lognormal 

distributions in each year for each dataset. The complete (all-worker) dataset has a higher 

standard deviation than the claimant dataset in many of the earlier years, but a lower standard 

deviation than the claimant dataset in the latest years. 

A scatter plot of the standard deviation of the plutonium concentrations for the claimant versus 

the complete datasets is shown in Figure 2-8. The dashed line in the figure at 45 degrees is the 

line of perfect equality. Again, the estimated regression line lies far below the line of perfect 

equality, indicating that the standard deviation for the complete dataset is higher than the mean 

for the claimant dataset in the earliest years when exposures are the highest. 

The estimated value for the slope and y-intercept of the regression lines in Figures 2-7 and 2-8 

and the standard error of each estimate for plutonium at the Mound Laboratory are shown in 

Table 2-2. The estimated slope and y-intercept of the regression line are compared to the ideal 

values of 1 and 0, respectively, using the t-test. The results of these hypotheses tests are also 

shown in Table 2-2. The hypotheses that the intercept is 0 and the slope is 1 are rejected in all 

cases. The conclusion is that the complete (all-worker) and claimant datasets for annual 

plutonium in urine concentrations at the Mound Laboratory show statistically significant 

differences at the annual level of aggregation after combining samples from all work areas and 

all job types. 

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.
Mean Plutonium Concentrations in Urine at Mound 

for Claimant and Complete Datasets

0

0.2

0.4

0.6

0.8

1

1955 1960 1965 1970 1975 1980 1985 1990 1995

Plutonium in Urine (pCi/day)

Complete Dataset (All Workers) Claimant Dataset

Figure 2-5: Mean Plutonium Concentrations in Urine at Mound for Claimant and 

Complete Datasets 

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Comparison of Mean Plutonium Concentrations at Mound

(1960 to 1990)

y = 0.533x + 0.056

R2

 = 0.730

0

0.2

0.4

0.6

0.8

1

0 0.2 0.4 0.6 0.8 1

Complete Mean (pCi/day)

Claimant Mean (pCi/day)

Figure 2-6: Comparison of Mean Plutonium Concentrations at Mound (1960 to 1990) 

Standard Deviation of Plutonium Concentrations in Urine at Mound

for Claimant and Complete Datasets

0

1

2

3

4

5

6

7

8

1955 1965 1975 1985 1995

Uranium in Urine (pCi/day)

Complete Dataset (All Workers) Claimant Dataset

Figure 2-7: Standard Deviation of Plutonium Concentrations in Urine at Mound for 

Claimant and Complete Datasets 
Comparison of Standard Deviation of Plutonium 

Concentrations at Mound (1960 to 1990)

y = 0.229x + 0.494

R2

 = 0.229

0

1

2

3

4

5

6

7

0123456

Complete Standard Deviation (pCi/day)

Claimant Standard Deviation (pCi/day)

7

Figure 2-8: Comparison of Standard Deviation of Plutonium Concentrations at Mound 

(1960 to 1990) 

Table 2-2: Summary of Regression Comparisons of Complete (All-Worker) and 

Claimant-Only Distributions for Plutonium at Mound Laboratory 

Years n 

Lognormal 

Distribution 

Parameter 

Regression 

Coefficient 

Estimated 

Coefficient

Standard 

Error of 

Estimate 

Hypothesis 

Tested 

t-statistic 

for Test 

p-level 

Pr{|X|>|t|}

Hypothesis 

Test 

Result 

1960 31 Mean Intercept 0.056 0.017 Intercept=0? 3.309 0.003 Reject 

to Slope 0.533 0.060 Slope=1? -7.754 0.000 Reject 

1990 R2 0.730 

 

Standard 

Deviation Intercept 0.494 0.146 Intercept=0? 3.378 0.002 Reject 

 Slope 0.229 0.078 Slope=1? -9.889 0.000 Reject 

 R2 0.229 

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NOTICE:
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2.3 COMPARISON OF CLAIMANT AND COMPLETE DATASETS FOR TRITIUM 

AT SRS 

The SRS analysis used tritium dose estimates for the years from 1991 to 2001, rather than tritium 

urine bioassay concentrations. The tritium doses were calculated from the tritium urine bioassay 

dataset extracted from the SRS HPRED13 database, which is considered complete for the period 

of 1990 onward. The reason presented by NIOSH for analyzing this particular all-worker dataset 

at SRS is that the data were readily available in electronic form. 

NIOSH presents a summary of the results of their study of the annual dose from tritium at SRS in 

Table 7-2 of OTIB-0075. The table shows the lognormal distributions estimated for the claimant 

and complete datasets in each year. All samples were combined into a single dataset for each 

year, with no differentiation by work area or job type. Figure 2-9 shows a time series plot 

comparing the mean annual tritium dose for each dataset. The claimant and complete (allworker) datasets are very similar in all years. 

A scatter plot of the mean annual tritium dose for the claimant versus the complete datasets at 

SRS is shown in Figure 2-10. The regression line is quite near the dashed line at 45 degrees, and 

the relatively high R2

 indicates good agreement between the two datasets during this time period. 

However, the sample size is small and nearly all values are at 3 to 4 mrem, with a single outlier 

at 6 mrem. The single outlier in 1991 almost entirely determines the slope of the regression line 

in this case. 

Figure 2-11 shows a time series plot comparing the standard deviation of the lognormal 

distributions in each year. The claimant and complete (all-worker) datasets are very similar in all 

years except 2000. A scatter plot of the standard deviation of the plutonium concentrations for 

the claimant versus the complete datasets is shown in Figure 2-12. The regression line is quite 

near the dashed line at 45 degrees, and the relatively high R2

 indicates good agreement between 

the two datasets during this time period. However, the sample size is small and nearly all values 

are at 1 to 3 mrem, with a single outlier at 6 mrem. Again, the single outlier in 1991 almost 

entirely determines the slope of the regression line. 

The estimated value for the slope and y-intercept of the regression line in Figure 2-12 and the 

standard error of estimate for the mean and standard deviation of tritium doses at SRS are shown 

in the upper portion of Table 2-3. The estimated slope and y-intercept of the regression line are 

compared to the ideal values of 1 and 0, respectively, using the t-test. The results of these 

hypotheses tests also are shown in Table 2-3. The hypotheses that the intercept is 0 and the slope 

is 1 are accepted in all cases. The conclusion is that the complete (all-worker) and claimant 

datasets for annual tritium doses at SRS show no statistically significant differences at the annual 

level of aggregation, combining samples from all work areas and all job types. However, the 

sample size at SRS is very small, and results are dominated by a single outlier year. 

A second comparison of the claimant and all-worker tritium datasets at SRS was conducted 

omitting the outlier year of 1991. Regressions for comparing the mean and the standard 

deviations in the years from 1992 to 2001 are shown in Figures 2-13 and 2-14, respectively. 
These regressions show no unduly influential data values from 1992 to 2001, and the regression 

lines fall near the line of equality. The t-test results in the lower portion of Table 2-3 indicate 

that the hypotheses of intercept equal to 0 and slope equal to 1 are accepted for mean and the 

standard deviation. 

Mean Annual Tritium Dose at SRS 

for Claimant and Complete Datasets

0

1

2

3

4

5

6

7

1990 1992 1994 1996 1998 2000 2002

Mean Annual Dose (mrem)

Complete Dataset (All Workers) Claimant Dataset

Figure 2-9: Mean Annual Tritium Dose at SRS for Claimant and Complete Datasets 

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Comparison of Mean Annual Tritium Dose at SRS

(1991 to 2001)

y = 1.152x - 0.671

R2

 = 0.858

0

1

2

3

4

5

6

7

01234567

Complete Mean (mrem)

Claimant Mean (mrem)

Figure 2-10: Comparison of Mean Annual Tritium Dose at SRS (1991 to 2001) 

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Figure 2-11: Standard Deviation of Annual Tritium Dose at SRS for 

Claimant and Complete Datasets 

Comparison of Standard Deviation of Annual Tritium 

Dose at SRS (1991 to 2001)

y = 1.078x - 0.217

R2

 = 0.854

0

1

2

3

4

5

6

7

01234567

Complete Standard Deviation (mrem)

Claimant Standard Deviation (mrem)

Standard Deviation of Annual Tritium Dose at SRS

for Claimant and Complete Datasets

0

1

2

3

4

5

6

1990 1992 1994 1996 1998 2000 2002

Mean Annual Dose (mrem)

Complete Dataset (All Workers) Claimant Dataset

Figure 2-12: Comparison of Standard Deviation of Annual Tritium Dose at SRS 

(1991 to 2001) 
Comparison of Mean Annual Tritium Dose at SRS

(1992 to 2001)

y = 0.915x + 0.217

R2

 = 0.430

2

3

4

5

2345

Complete Mean (mrem)

Claimant Mean (mrem)

Figure 2-13: Comparison of Mean Annual Tritium Dose at SRS (1992 to 2001) 

SRS – Draft Review of OTIB-0075 28 SC&A – January 13, 2010 

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Health for factual accuracy or applicability within the requirements of 42 CFR 82. 

Comparison of Standard Deviation of Annual Tritium 

Dose at SRS (1992 to 2001)

y = 0.962x + 0.037

R2

 = 0.529

1

2

3

4

1234

Complete Standard Deviation (mrem)

Claimant Standard Deviation (mrem)

Figure 2-14: Comparison of Standard Deviation of Annual Tritium Dose at SRS 

(1992 to 2001) 
SRS – Draft Review of OTIB-0075 29 SC&A – January 13, 2010 

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Table 2-3: Summary of Regression Comparisons of Complete (All-Worker) and 

Claimant-Only Distributions for Tritium at SRS 

Years n 

Lognormal 

Distribution 

Parameter 

Regression 

Coefficient 

Estimated 

Coefficient

Standard 

Error of 

Estimate

Hypothesis 

Tested 

t-statistic 

for Test 

p-level 

Pr{|X|>|t|}

Hypothesis 

Test 

Result 

1991 11 Mean Intercept -0.671 0.622 Intercept=0? -1.079 0.309 Accept 

to Slope 1.152 0.156 Slope=1? 0.973 0.356 Accept 

2001 R2 0.858 

 

 

Standard 

Deviation Intercept -0.217 0.410 Intercept=0? -0.530 0.609 Accept 

 Slope 1.078 0.149 Slope=1? 0.526 0.611 Accept 

 R2 0.854 

1992 10 Mean Intercept 0.217 1.409 Intercept=0? 0.15 0.881 Accept 

to Slope 0.915 0.372 Slope=1? -0.23 0.825 Accept 

2001 R2 0.430 

 

 

Standard 

Deviation Intercept 0.037 0.750 Intercept=0? 0.05 0.962 Accept 

 Slope 0.962 0.321 Slope=1? -0.12 0.909 Accept 

R2 0.529 

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 are 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 show no significant difference at the annual 

level of aggregation 

In the particular case of the SRS site, the OTIB-0075 study only addressed tritium exposures in 

the late years of operations at the site. Figure 2-11 shows evidence of a continuing exponential 

decline in mean annual tritium doses to all workers during this time period, indicating a residual 

nature of the tritium contamination. During essentially the whole period studied, many of the 

production and processing facilities, such as production reactors, had ceased operation. Note that 

the production reactors were the facilities in which the SRS tritium was created. 

3.0 OVERVIEW COMMENTS ON OTIB-0075 

The tritium data that were available in electronic form for the SRS site represent only a small 

fraction of the coworker exposure data that are available in hardcopy for this site. The entire 

exposure dataset at SRS includes a large amount of uranium and plutonium coworker exposure 

data that were not available in electronic form. No comparison of claimant and general worker 

exposures to uranium or transuranics is possible, because NIOSH has not yet assembled the 

complete dataset of SRS worker exposures into an electronic database. 
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At SRS, the potentially available coworker exposure database is large, but it is not available 

electronically. It is possible that the use of all the available data could support separate analyses 

of coworker exposures by quarter, work area (H Canyon versus F Canyon, etc.), and job type. 

Use of aggregated collections of claimant data in lieu of such detailed coworker data results in a 

great loss of occupational and area detail. This loss of critical information is not mentioned in 

OTIB-0075, which assumes that all claimants working at SRS in a given year are 

interchangeable, regardless of job type or work area. No consideration is given by NIOSH to the 

fact that the estimates derived using a coworker model based on all claimant data taken together 

would be not be claimant favorable for many sub-groups of claimants at the site. The study, at 

best, demonstrates that the estimates would be, on average, in the same ballpark for tritium in a 

limited period. In this case, the term “on average” means that for some groups of claimants, the 

estimates derived using this proposal will be too low, and for other groups of claimants, the 

estimates will be too high. This is not a claimant-favorable approach to dose estimation, because 

it ignores the known differences between work areas and job types that would become evident if 

the hardcopy data for all SRS workers in all years were available for analysis. 

FINDING #4: At SRS, OTIB-0075 includes data only for tritium from 1991 to 2001 in 

comparing the claimant population to that of all workers. This is a very partial and 

incomplete basis for any overall conclusion about the relationship of claimant data to allworker data. Analysis for other radionuclides, including uranium, plutonium, and fission 

products, can only be done if the available hardcopy data are reduced to electronic form. The 

same applies to tritium data prior to 1991. In all these cases, the validity of the central 

hypothesis of OTIB-0075 for SRS cannot be checked until the necessary hardcopy data are 

put into electronic form. 

FINDING #5: Data for the entire SRS in OTIB-0075 were aggregated by year for the NIOSH 

analysis, with no detail by work area or by job type. The proposal for a NIOSH coworker 

model includes no analysis of these details. 

With regard to the Y-12 Plant, NIOSH has an electronic coworker uranium urine bioassay 

dataset available for the years 1950 to 1988. This dataset was developed by the Oak Ridge 

Institute for Science and Engineering (ORISE) Center for Epidemiologic Research (CER) for use 

in epidemiology studies (Watkins et al. 1993) and has undergone detailed verification of its 

integrity.1

 A member of the complete dataset is referred to as a worker. The uranium bioassay 

database contains approximately 470,000 bioassays from over 7,500 workers. The subset of 

claimants with uranium bioassay data comprises approximately 10% of the workers and 

approximately 15% of the bioassays in the complete coworker database. 

This dataset has been named as a “complete” coworker dataset. However, in regard to the 

claimant data at this site, NIOSH states the following. 

1

 Note that the procedure used by Oak Ridge to prepare and validate a uranium exposure dataset in 

electronic form at Y-12 is precisely what will be required at SRS if the current NIOSH proposal is deemed not to be 

a claimant-favorable approach for coworker dose estimation. 
SRS – Draft Review of OTIB-0075 31 SC&A – January 13, 2010 

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Health for factual accuracy or applicability within the requirements of 42 CFR 82. 

NOTICE:

Out of 1,971 total claimants for Y-12, 731 have uranium urine bioassay results in 

the complete dataset and 1,240 do not (presumably because they were not 

monitored). 

Note that only 731 out of 1,971 claimants (37%) had data in the “complete” coworker database. 

For the claimants with data, 67,923 uranium urine samples were found in the coworker database. 

The median claimant had 46 samples over the 39-year monitoring period; a little more than 1 

assay per year. 

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.

FINDING #7: Data for the entire Y-12 site were aggregated by year for the NIOSH analysis, 

with no detail by work area or by job type. The NIOSH coworker model includes no analysis 

of these details. 

At the Mound Laboratory, the plutonium urine bioassay dataset PURECON provided “complete” 

coworker data for the years 1960 to 1990, with 225 claimants identified in the database. No 

information is provided on the fraction of all Mound claimants represented by the claimants with 

data in the complete coworker database. The database contains 2,070 workers who submitted a 

total of 53,340 plutonium urine bioassay samples. The 225 claimants with bioassay data 

submitted 8,849 plutonium urine samples. The median claimant submitted 24 samples over the 

31-year monitoring period.

At the Mound Laboratory, the complete coworker plutonium bioassay database contains 

approximately 53,000 bioassays from over 2,000 workers. The subset of 225 claimants with 

plutonium bioassay data comprises approximately 11% of the workers and approximately 17% 

of the bioassays in the complete coworker database. The fraction of all claimants who were 

found to have data in the complete database is not reported. 

FINDING #8: Data for the entire Mound Laboratory were aggregated by year for the NIOSH 

analysis, with no detail by work area or by job type. The NIOSH coworker model includes no 

attention to these details. 

None of the above analyses compares construction worker claimants to non-construction worker 

claimants. In effect, OTIB-0075 does not have any analysis that would establish the validity of 

the hypothesis that all claimant data at any site, including SRS, are representative of construction 

worker data for that site for various periods and radionuclides.
SRS – Draft Review of OTIB-0075 32 SC&A – January 13, 2010 

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Health for factual accuracy or applicability within the requirements of 42 CFR 82. 

4.0 ANALYSIS OF SRS CLAIMANT EXPOSURES BY WORK AREA 

AND JOB TYPE 

Because much of the SRS sample data have not been transferred from its paper files to an 

electronic file, NIOSH is proposing to utilize the NIOSH OCAS Claims Tracking System 

(NOCTS) as its source of coworker data. NOCTS is a database of sample results for all Energy 

Employee Occupational Illness Compensation Program Act (EEOICPA) claimants. The NOCTS 

SRS sample results are stored on the O-drive in the files “Non-CW Coworker Data.xls” and 

“CW Coworker Data Test.xls.” In this evaluation, the data from “Non-CW Coworker Data.xls” 

and “CW Coworker Data Test.xls” were used to compare the 84th percentile sample results of 

construction workers to non-construction workers for the entire SRS, as well as for specific areas 

within the SRS. Comparisons were made for tritium, plutonium, uranium, enriched uranium, and 

fission products, since those were the radionuclides with the most non-construction worker 

sample results. Specifically, we have not analyzed several other radionuclides of interest, 

including americium-241, curium-244, californium-252, and neptunium-237. There are very 

scant data in NOCTS for construction workers for these radionuclides during the main 

operational period of nuclear materials production up to and including 1988, except for just 

under a hundred samples for americium or “americium-curium,” almost all of which are for the 

1970s and 1980s, and the vast majority of them were taken from [redact]. 

 Assumptions made for this evaluation include the following: 

 Samples were determined to be unusable and not included if they (1) do not have a valid 

year, (2) do not have valid units, (3) have a zero result, or (4) contain data that would 

make it impossible to perform the calculations. 

 No calculation (n/c) was performed if there were less than 100 usable non-construction 

worker sample results available for any combination of radionuclide, time period, and 

area. Because there are fewer construction worker samples, no calculation (n/c) was 

performed if there were less than 10 usable construction worker sample results available. 

 In the O-drive files, plutonium results are reported as Pu, Pu-238/239, Pu-238, and 

Pu-239. All of these results were included in the plutonium calculations, but the Pu and 

Pu-238/239 (mostly pre-1981) results were divided by 2 to be consistent with the Pu-238 

and Pu-239 results (mostly 1981 and later). 

 All results were converted to units of μCi/L for tritium and dpm/L for the other 

radionuclides. This assumption differs from how NIOSH handles units when developing 

their coworker data, which were in units of dpm/day for other radionuclides. 

The results of this SC&A evaluation of the NOCTS data are shown in two series of tables, one 

for non-construction worker claimants and one for construction worker claimants. Due to the 

large number of tables, all summary data tables are presented in the appendices. Table A-1 in 

Appendix A contains the number of tritium sample results from SRS non-construction worker 

claimants by work area and decade from the 1950s to the 2000s. The number of samples ranges 
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from 1 to over 16,000 samples in a given year. The 84th percentile of tritium exposure in each 

work area and decade is shown in Table A-2. Tables B-1 and B-2 in Appendix B show similar 

results for construction worker claimants. The number of samples from construction worker 

claimants is much smaller, ranging from 1 to over 1,600. Note there are also fewer work areas 

with samples from construction worker claimants (7) than for non-construction worker claimants 

(13). 

Tables A-3 and A-4 in Appendix A show similar results for plutonium bioassay samples from 

non-construction worker claimants. There are fewer work areas with non-construction worker 

claimant plutonium samples. The number of samples ranges from 2 to over 1,800 samples per 

decade. Tables B-3 and B-4 in Appendix B show similar results for the construction worker 

claimants. 

Tables A-5 and A-6 show the results for non-construction worker uranium bioassay samples, 

Tables A-7 and A-8 for enriched uranium, and Tables A-9 and A-10 for fission products. 

Similar results for construction worker claimants are shown for uranium in Tables B-5 and B-6, 

for enriched uranium in Tables B-7 and B-8, and for fission products in Tables B-9 and B-10. 

4.1 COMPARISON OF NON-CONSTRUCTION WORKER EXPOSURES BY WORK 

AREA 

A summary of the 84th percentile estimates for non-construction worker claimants contained in 

the tables of Appendix A is presented in Table 4-1. This table contains the ratio of 84th

percentile for non-construction workers in the specified work area over the 84th percentile for 

non-construction workers in all work areas (first row of data in Tables A-2, A-4, A-6, A-8 and 

A-10). The five types of exposures are shown in the table. The purpose of this table is to 

demonstrate that non-construction workers in different work areas have different levels of 

exposures, and hence should not be assigned exposures estimated from claimant data for all work 

areas combined. 

Some entries in Table 4-1 are less than 1 and some are greater than 1. When the ratio is less than 

1, the estimated missed dose would be claimant favorable, higher than typical exposures in that 

work area. But when the ratio is greater than 1, the estimated missed dose would not be claimant 

favorable, lower than typical exposures in that work area. The degree to which the numbers in 

Table 4-1 differ from 1.0 is a measure of the error expected if the NIOSH proposal of using 

aggregated NOCTS claimant data were used to assign missed doses to non-construction worker 

claimants. 

In the case of tritium in the 1950s in Table 4-1, all the ratios shown exceed unity. This is due to 

the large number of workers with missing work area information in NOCTS in the 1950s, as 

shown near the bottom of Table A-1. 

 
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Table 4-1: Ratio of 84th Percentile for Non-Construction Workers in Specified Work 

Areas over 84th Percentile for Non-Construction Workers in All Work Areas 

 Work Area 1950s 1960s 1970s 1980s 1990s 2000s 

Tritium

 C-Area 5.45 1.67 1.00 1.00 0.50 n/c 

 F-Area 4.05 n/c n/c n/c n/c n/c 

 H-Area n/c 0.17 0.50 0.50 0.50 0.56 

 K-Area 1.82 1.00 1.50 1.30 1.50 n/c 

 L-Area 1.91 1.67 n/c 0.25 0.50 n/c 

 P-Area 3.64 1.33 1.00 1.00 2.00 n/c 

 R-Area 2.73 1.33 n/c n/c n/c n/c 

 Plutonium

 A-Area n/c 0.74 0.06 1.00 n/c n/c 

 F-Area 0.87 0.74 0.47 1.70 n/c n/c 

 H-Area 1.30 2.91 14.98 1.00 n/c n/c 

 Uranium

 F-Area n/c 1.44 1.00 1.00 n/c n/c 

 M-Area n/c 1.00 1.00 1.00 n/c n/c 

 Enriched Uranium

 M-Area n/c n/c 1.82 1.00 n/c n/c 

 Fission Products

 F-Area n/c 1.00 n/c 1.00 n/c n/c 

 H-Area n/c 1.00 n/c 1.00 n/c n/c 

n/c: Not calculated 

A bar plot of the tritium ratios in Table 4-1 comparing the level of non-construction worker 

exposures in specific areas to aggregate exposures of non-construction workers over all areas is 

shown in Figure 4-1. Horizontal lines are drawn at a ratio of 1. The largest deviations from 1 

are labeled with the value of the ratio. Other than in the 1950s, when there were few samples 

with identified work areas, the largest deviations from 1 occur in the 1990s, with a ratio of 2.0. 
Figure 4-1: Ratio of 84th Percentile of Tritium Samples from Non-Construction Workers 

(NCW) in Specified Work Areas over 84th Percentile of Tritium Samples from NonConstruction Workers in All Work Areas, by Decade 

Table 4-2 contains the ratio of the GSD for non-construction workers in the specified work area 

over the GSD for non-construction workers in all work areas. The GSD, calculated as the ratio 

of the 84th percentile over the 50th percentile, is always greater than or equal to 1. The GSD is a 

measure of the spread of the distribution of bioassays in the specified area, while the 50th and 

84th percentiles are measures of the level of the distribution. When the median for the work area 

is equal to the median for all work areas, the ratio of the corresponding GSDs will be the same as 

the ratio of the 84th percentiles shown in Table 4-1. 

A plot of the GSD ratios for tritium shown in Table 4-2 is presented in Figure 4-2. The 

horizontal line in each plot is drawn at a value of 1.0. The GSD of the non-construction workers 

in Areas C, F, K, L, P, and R exceeds the GSD for non-construction workers in all areas 

combined. Again, this is due to the large number of workers with missing work area information 

in NOCTS in the 1950s, as shown near the bottom of Table A-1. 

SRS – Draft Review of OTIB-0075 35 SC&A – January 13, 2010 

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Table 4-2: Ratio of GSD for Non-Construction Workers in Specified Work Areas over 

GSD for Non-Construction Workers in All Work Areas 

 Work Area 1950s 1960s 1970s 1980s 1990s 2000s 

Tritium

 C-Area 2.73 0.83 1.00 1.00 0.50 n/c 

 F-Area 2.03 n/c n/c n/c n/c n/c 

 H-Area n/c 0.17 1.00 0.50 0.50 0.56 

 K-Area 1.82 1.00 1.50 0.65 0.75 n/c 

 L-Area 1.91 0.42 n/c 0.25 0.50 n/c 

 P-Area 3.64 0.33 1.00 0.63 1.00 n/c 

 R-Area 2.73 0.67 n/c n/c n/c n/c 

 Plutonium

 A-Area n/c 0.74 0.06 1.00 n/c n/c 

 F-Area 0.87 0.74 0.47 1.70 n/c n/c 

 H-Area 1.30 2.91 14.98 1.00 n/c n/c 

 Uranium

 F-Area n/c 1.44 1.00 0.23 n/c n/c 

 M-Area n/c 1.00 4.43 1.00 n/c n/c 

 Enriched Uranium 

 M-Area n/c n/c 1.21 1.00 n/c n/c 

 Fission Products

 F-Area n/c 1.00 n/c 1.00 n/c n/c 

 H-Area n/c 1.00 n/c 1.00 n/c n/c 

n/c: Not calculated 

Figure 4-2: Ratio of GSD of Tritium Samples from Non-Construction Workers (NCW) 

in Specified Work Areas over GSD of Tritium Samples from Non-Construction Workers in 

All Work Areas, by Decade 

SRS – Draft Review of OTIB-0075 36 SC&A – January 13, 2010 

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Health for factual accuracy or applicability within the requirements of 42 CFR 82. 
A plot for the ratio of the 84th percentile of plutonium bioassays in the specified work area over 

the 84th percentile for all work areas combined is shown in Figure 4-3. Several large ratios are 

observed in the P-Area in the 1960s and 1970s. The 84th percentile of non-construction worker 

exposure in P-Area exceeded the 84th percentile of plutonium exposure for all non-construction 

worker claimants by a factor of 15 in the 1970s, and by almost a factor of 3 in the 1960s. 

Table 4-2 contains ratios of the GSD of plutonium bioassays in the specified work area over the 

GSD in all work areas. A plot of these ratios is shown in Figure 4-4. When the ratio of the 

GSDs exceeds 1, the distribution of samples from non-construction workers in the specified 

work area has a wider spread than the distribution for non-construction workers in all work areas. 

The GSD ratios in H-Area show large discrepancies in the 1960s and 1970s. 

Table 4-1 also contains ratios of the 84th percentile of uranium bioassays from non-construction 

workers in the specified work area over the 84th percentile for non-construction workers in all 

work areas combined. A plot of these ratios is shown in Figure 4-5. The ratios are all close to 1, 

indicating good agreement in the 84th percentiles. The ratio of the GSD of uranium bioassays in 

the specified work area over the GSD in all work areas is plotted in Figure 4-6. A large ratio of 

over a factor of 4 is observed for the GSD in M-Area in the 1970s. 

Figure 4-3: Ratio of 84th Percentile of Plutonium Samples from Non-Construction 

Workers (NCW) in Specified Work Areas over 84th Percentile of Plutonium Samples from 

Non-Construction Workers in All Work Areas, by Decade 

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Figure 4-4: Ratio of GSD of Plutonium Samples from Non-Construction Workers 

(NCW) in Specified Work Areas over GSD of Plutonium Samples from Non-Construction 

Workers in All Work Areas, by Decade 

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Health for factual accuracy or applicability within the requirements of 42 CFR 82. 
Figure 4-5: Ratio of 84th Percentile of Uranium Samples from Non-Construction 

Workers (NCW) in Specified Work Areas over 84th Percentile of Uranium Samples from 

Non-Construction Workers in All Work Areas, by Decade 

Figure 4-6: Ratio of GSD of Uranium Samples from Non-Construction Workers (NCW) 

in Specified Work Areas over GSD of Uranium Samples from Non-Construction Workers 

in All Work Areas, by Decade 

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However, this report is pre-decisional and has not been reviewed by the Advisory Board on Radiation and Worker 

Health for factual accuracy or applicability within the requirements of 42 CFR 82. 

FINDING #9: At SRS, the 84th percentile of exposures to tritium, plutonium, uranium, and 

other radionuclides for non-construction workers in specific work areas show considerable 

differences from the 84th percentile of exposures to non-construction workers site-wide. 

Similar results are observed for the corresponding ratio of the GSDs. 

4.2 COMPARISON OF CONSTRUCTION WORKER AND NON-CONSTRUCTION 

WORKER EXPOSURES 

A comparison of the 84th percentile estimates for non-construction worker and construction 

worker claimants in the tables of Appendices A and B, respectively, is presented in Table 4-3. 

This table shows the ratio of the 84th percentile for construction workers in the specified work 

area divided by the 84th percentile for non-construction workers in all work areas. This ratio has 

the same denominator that was used for the ratios in Table 4-1 (first row of data in Tables A-2, 

A-4, A-6, A-8, and A-10). The purpose of Table 4-3 is to show that the NIOSH proposal to use 

non-construction worker claimant data for estimating missed doses to construction workers will 

underestimate the dose for some construction worker claimants and overestimate the dose to 

other construction worker claimants, in some cases by a large amount. 

A bar plot of the tritium ratios in Table 4-3 comparing construction worker exposures in specific 

areas to aggregate exposures for non-construction worker over all areas is shown in Figure 4-7. 

Horizontal lines are drawn at a ratio of 1. The plot shows that the 84th percentile for construction 

worker claimants in specified work areas exceeds the 84th percentile for non-construction 

workers by factors of 2.5 to 5 in many work areas in the 1950s, in K-Area and P-Area in the 

1090s, and in H-Area in the 2000s. The NIOSH proposal would not be claimant favorable for 

construction worker claimants who worked in these areas. 

Table 4-4 contains the ratio of the GSD for biosamples from construction workers in the 

specified work area over the GSD for non-construction workers in all work areas. When the 

ratio of the GSDs exceeds 1, the distribution of samples from construction workers in the 

specified work area has a wider spread than the distribution for non-construction workers in all 

work areas. The GSDs differ by large factors in Areas F, K, and P in the 1950s, and in H-Area 

in the 2000s. 

A plot for the ratio of the 84th percentiles of plutonium exposure for the construction worker and 

non-construction worker claimants is shown in Figure 4-9. Large ratios are observed in F-Area 

and P-Area in the 1980s, ranging from 1.7 to 2.0. The NIOSH proposal would not be claimant 

favorable for construction worker claimants who worked in these areas. 

Table 4-4 contains the ratio of the GSD of plutonium bioassays from construction workers in the 

specified work area over the GSD for non-construction workers in all work areas. These ratios 

are plotted in Figure 4-10. Very low ratios are noted in the 1970s for Areas A, F and H. These 

low ratios are due to the relatively high mean and GSD of the plutonium samples for nonconstruction workers in H-Area in this decade, as shown in Figures 4-3 and 4-4. 

A plot for the ratio of the 84th percentile of uranium bioassays from construction workers in the 

specified work area over the 84th percentile for non-construction workers in all work areas 
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combined is shown in Figure 4-11. Several large ratios are observed in F-Area in the 1970s and 

M-Area in the 1960s. Table 4-4 shows the ratio of the GSD of uranium bioassays in the 

specified work area over the GSD in all work areas. A plot of these ratios is shown in 

Figure 4-12. Again, large ratios are observed in F-Area in the 1970s and M-Area in the 1960s. 

FINDING #10: At SRS, the 84th percentile of exposures to tritium, plutonium, and other 

radionuclides for construction workers in specific work areas show considerable differences 

from the 84th percentile of exposures to all non-construction workers site-wide. Similar results 

are observed for the corresponding ratio of the GSDs. 

Table 4-3: Ratio of 84th Percentile for Construction Workers in Specified Work Areas 

over 84th Percentile for Non-Construction Workers in All Work Areas 

 Work Area 1950s 1960s 1970s 1980s 1990s 2000s 

Tritium

 C-Area 2.73 2.00 1.00 1.00 0.25 n/c 

 F-Area 3.04 n/c n/c n/c n/c n/c 

 H-Area n/c 0.17 0.25 0.50 0.25 3.33 

 K-Area 4.55 1.00 1.00 1.50 2.50 n/c 

 L-Area 0.91 2.00 n/c 0.25 1.00 n/c 

 P-Area 5.45 2.00 1.00 1.10 3.00 n/c 

 R-Area 0.45 1.67 n/c n/c n/c n/c 

 Plutonium

 A-Area n/c 1.43 0.12 1.00 n/c n/c 

 F-Area 0.74 1.43 0.12 1.70 n/c n/c 

 H-Area 1.00 1.43 0.23 2.03 n/c n/c 

 Uranium

 F-Area n/c 1.49 3.34 1.00 n/c n/c 

 M-Area n/c 2.00 0.23 0.23 n/c n/c 

 Enriched Uranium

 M-Area n/c n/c 0.17 0.96 n/c n/c 

 Fission Products

 F-Area n/c 1.00 n/c 1.00 n/c n/c 

 H-Area n/c 1.00 n/c 1.00 n/c n/c 

n/c: Not calculated 
Table 4-4: Ratio of GSD for Construction Workers in Specified Work Areas over GSD 

for Non-Construction Workers in All Work Areas 

 Work Area 1950s 1960s 1970s 1980s 1990s 2000s 

Tritium

 C-Area 1.36 0.50 1.00 1.00 0.25 n/c 

 F-Area 3.04 n/c n/c n/c n/c n/c 

 H-Area n/c 0.17 0.50 0.50 0.25 3.33 

 K-Area 3.03 1.00 1.00 1.25 1.25 n/c 

 L-Area 0.91 0.50 n/c 0.25 0.50 n/c 

 P-Area 5.45 0.50 1.00 0.69 0.50 n/c 

 R-Area 0.45 0.83 n/c n/c n/c n/c 

 Plutonium

 A-Area n/c 0.74 0.06 0.52 n/c n/c 

 F-Area 0.35 0.74 0.06 0.87 n/c n/c 

 H-Area 0.47 0.74 0.12 1.05 n/c n/c 

 Uranium

 F-Area n/c 1.49 3.34 1.13 n/c n/c 

 M-Area n/c 2.00 1.00 0.23 n/c n/c 

 Enriched Uranium

 M-Area n/c n/c 0.17 0.96 n/c n/c 

 Fission Products

 F-Area n/c 1.00 n/c 1.00 n/c n/c 

 H-Area n/c 1.00 n/c 1.00 n/c n/c 

n/c: Not calculated 

Figure 4-7: Ratio of 84th Percentile of Tritium Samples from Construction Workers 

(CW) in Specified Work Areas over 84th Percentile of Tritium Samples from 

Non-Construction Workers (NCW) in All Work Areas, by Decade 

SRS – Draft Review of OTIB-0075 42 SC&A – January 13, 2010 

NOTICE: This report has been reviewed for Privacy Act information and has been cleared for distribution. 

However, this report is pre-decisional and has not been reviewed by the Advisory Board on Radiation and Worker 

Health for factual accuracy or applicability within the requirements of 42 CFR 82. 
Figure 4-8: Ratio of GSD of Tritium Samples from Construction Workers (CW) in 

Specified Work Areas over GSD of Tritium Samples from Non-Construction Workers 

(NCW) in All Work Areas, by Decade 

Figure 4-9: Ratio of 84th Percentile of Plutonium Samples from Construction Workers 

(CW) in Specified Work Areas over 84th Percentile of Plutonium Samples from 

Non-Construction Workers (NCW) in All Work Areas, by Decade 

SRS – Draft Review of OTIB-0075 43 SC&A – January 13, 2010 

NOTICE: This report has been reviewed for Privacy Act information and has been cleared for distribution. 

However, this report is pre-decisional and has not been reviewed by the Advisory Board on Radiation and Worker 

Health for factual accuracy or applicability within the requirements of 42 CFR 82. 
Figure 4-10: Ratio of GSD of Plutonium Samples from Construction Workers (CW) in 

Specified Work Areas over GSD of Plutonium Samples from Non-Construction Workers 

(NCW) in All Work Areas, by Decade 

Figure 4-11: Ratio of 84th Percentile of Uranium Samples from Construction Workers 

(CW) in Specified Work Areas over 84th Percentile of Uranium Samples from NonConstruction Workers (NCW) in All Work Areas, by Decade 

SRS – Draft Review of OTIB-0075 44 SC&A – January 13, 2010 

NOTICE: This report has been reviewed for Privacy Act information and has been cleared for distribution. 

However, this report is pre-decisional and has not been reviewed by the Advisory Board on Radiation and Worker 

Health for factual accuracy or applicability within the requirements of 42 CFR 82. 
Figure 4-12: Ratio of GSD of Uranium Samples from Construction Workers (CW) in 

Specified Work Areas over GSD of Uranium Samples from Non-Construction Workers 

(NCW) in All Work Areas, by Decade 

4.3 COMPARISON OF CONSTRUCTION WORKER EXPOSURES BY AREA 

Table 4-5 shows the ratio of 84th percentile for construction workers in the specified work areas 

divided by the 84th percentile for construction workers in all work areas (first row of data in 

Tables B-2, B-4, B-6, B-8 and B-10). The purpose of this table is to show that sizeable 

differences occur between work areas for construction worker claimants if site-wide claimant 

data from construction workers were used to estimate missed doses. It should be noted that data 

for construction worker exposure to uranium, enriched uranium, and fission products are sparse, 

preventing the calculation of ratios in many decades. In general, the discrepancies for tritium 

and plutonium are found to be larger than those observed in a similar comparison for nonconstruction workers in Tables 4-1 and 4-2. 

A plot of the tritium 84th percentile ratios in Table 4-5 comparing construction worker exposures 

in specific areas to aggregate exposures for construction workers over all areas is presented in 

Figure 4-13. The plot shows that the 84th percentile for construction worker claimants in 

specified work areas exceeds the 84th percentile for all construction workers in K-Area and 

P-Area in the 1950s. The NIOSH proposal would not be claimant favorable in these areas if the 

coworker model for construction workers included site-wide data from construction worker 

claimants. 

Table 4-6 contains the ratio of the GSD for tritium samples from construction workers in the 

specified work area over the GSD for construction workers in all work areas. When the ratio of 

the GSDs exceeds 1, the distribution of samples from construction workers in the specified work 

SRS – Draft Review of OTIB-0075 45 SC&A – January 13, 2010 

NOTICE: This report has been reviewed for Privacy Act information and has been cleared for distribution. 

However, this report is pre-decisional and has not been reviewed by the Advisory Board on Radiation and Worker 

Health for factual accuracy or applicability within the requirements of 42 CFR 82. 
SRS – Draft Review of OTIB-0075 46 SC&A – January 13, 2010 

NOTICE: This report has been reviewed for Privacy Act information and has been cleared for distribution. 

However, this report is pre-decisional and has not been reviewed by the Advisory Board on Radiation and Worker 

Health for factual accuracy or applicability within the requirements of 42 CFR 82. 

area has a wider spread than the distribution for construction workers in all work areas. The 

GSD ratios for tritium are shown in Figure 4-14. The GSD for construction worker claimants in 

specified work areas exceeds the 84th percentile for all construction workers in F-Area, K-Area 

and P-Area in the 1950s. 

A plot of the plutonium ratios in Table 4-5 comparing construction worker exposures in specific 

areas to aggregate exposures for construction workers over all areas is shown in Figure 4-15. 

The plot shows that the 84th percentile for construction worker claimants in specified work areas 

exceeds the 84th percentile for all construction workers in H-Area in the 1950s, 1970s, and 

1980s. 

Table 4-6 contains the ratio of the GSD of plutonium bioassays from construction workers in the 

specified work area over the GSD for construction workers in all work areas. These ratios are 

plotted in Figure 4-16. Most ratios are near 1, except for H-Area in the 1970s. 

A plot for the ratio of the 84th percentile of uranium bioassays from construction workers in the 

specified work area over the 84th percentile for construction workers in all work areas combined 

is presented in Figure 4-17. A large ratio of the 84th percentiles is observed in F-Area in the 

1980s, exceeding a factor of 4. Table 4-6 also contains the ratio of the GSD of uranium 

bioassays in the specified work area over the GSD in all work areas. The GSD ratios are 

graphed in Figure 4-18. Again, a large ratio is observed in F-Area in the 1980s, exceeding a 

factor of 5. 

FINDING #11: At SRS, the 84th percentile of exposures to tritium and plutonium for 

construction workers in specific work areas show considerable differences from the 84th

percentile of site-wide exposures to construction workers. Similar results are observed for the 

corresponding ratio of the GSDs. In many cases, there are insufficient data for construction 

workers to make a comparison for uranium, enriched uranium and fission products. 
SRS – Draft Review of OTIB-0075 47 SC&A – January 13, 2010 

NOTICE: This report has been reviewed for Privacy Act information and has been cleared for distribution. 

However, this report is pre-decisional and has not been reviewed by the Advisory Board on Radiation and Worker 

Health for factual accuracy or applicability within the requirements of 42 CFR 82. 

Table 4-5: Ratio of 84th Percentile for Construction Workers in Specified Work Areas 

over 84th Percentile for Construction Workers in All Work Areas 

 Work Area 1950s 1960s 1970s 1980s 1990s 2000s 

Tritium

 C-Area 1.76 1.20 1.00 1.00 0.13 n/c 

 F-Area 1.96 n/c n/c n/c n/c n/c 

 H-Area n/c 0.10 0.25 0.50 0.13 1.11 

 K-Area 2.94 0.60 1.00 1.50 1.25 n/c 

 L-Area 0.59 1.20 n/c 0.25 0.50 n/c 

 P-Area 3.53 1.20 1.00 1.10 1.50 n/c 

 R-Area 0.29 1.00 n/c n/c n/c n/c 

 Plutonium

 A-Area n/c 1.00 1.00 0.59 n/c n/c 

 F-Area 1.00 1.00 1.00 1.00 n/c n/c 

 H-Area 1.35 1.00 1.85 1.20 n/c n/c 

 Uranium

 F-Area n/c 0.74 1.67 4.43 n/c n/c 

 M-Area n/c 1.00 0.11 1.00 n/c n/c 

 Enriched Uranium

 M-Area n/c n/c 1.00 0.53 n/c n/c 

 Fission Products

 F-Area n/c 1.00 n/c 1.00 n/c n/c 

 H-Area n/c 1.00 n/c 1.00 n/c n/c 

n/c: Not calculated 

Table 4-6: Ratio of GSD for Construction Workers in Specified Work Areas over GSD 

for Construction Workers in All Work Areas 

 Work Area 1950s 1960s 1970s 1980s 1990s 2000s 

Tritium

 C-Area 0.88 0.60 1.00 1.00 0.25 n/c 

 F-Area 1.96 n/c n/c n/c n/c n/c 

 H-Area n/c 0.20 0.50 0.50 0.25 1.11 

 K-Area 1.96 1.20 1.00 1.25 1.25 n/c 

 L-Area 0.59 0.60 n/c 0.25 0.50 n/c 

 P-Area 3.53 0.60 1.00 0.69 0.50 n/c 

 R-Area 0.29 1.00 n/c n/c n/c n/c 

 Plutonium

 A-Area n/c 1.00 1.00 0.59 n/c n/c 

 F-Area 1.00 1.00 1.00 1.00 n/c n/c 

 H-Area 1.35 1.00 1.85 1.20 n/c n/c 

 Uranium

 F-Area n/c 0.74 0.38 5.01 n/c n/c 

 M-Area n/c 1.00 0.11 1.00 n/c n/c 

 Enriched Uranium

 M-Area n/c n/c 1.00 0.71 n/c n/c 

 Fission Products 

 F-Area n/c 1.00 n/c 1.00 n/c n/c 

 H-Area n/c 1.00 n/c 1.00 n/c n/c 

n/c: Not calculated 
Figure 4-13: Ratio of 84th Percentile of Tritium Samples from Construction Workers 

(CW) in Specified Work Areas over 84th Percentile of Tritium Samples from Construction 

Workers in All Work Areas, by Decade 

Figure 4-14: Ratio of GSD of Tritium Samples from Construction Workers (CW) in 

Specified Work Areas over GSD of Tritium Samples from Construction Workers 

in All Work Areas, by Decade 

SRS – Draft Review of OTIB-0075 48 SC&A – January 13, 2010 

NOTICE: This report has been reviewed for Privacy Act information and has been cleared for distribution. 

However, this report is pre-decisional and has not been reviewed by the Advisory Board on Radiation and Worker 

Health for factual accuracy or applicability within the requirements of 42 CFR 82. 
Figure 4-15: Ratio of 84th Percentile of Plutonium Samples from Construction Workers 

(CW) in Specified Work Areas over 84th Percentile of Plutonium Samples from 

Construction Workers in All Work Areas, by Decade 

Figure 4-16: Ratio of GSD of Plutonium Samples from Construction Workers (CW) in 

Specified Work Areas over GSD of Plutonium Samples from Construction Workers in All 

Work Areas, by Decade 

SRS – Draft Review of OTIB-0075 49 SC&A – January 13, 2010 

NOTICE: This report has been reviewed for Privacy Act information and has been cleared for distribution. 

However, this report is pre-decisional and has not been reviewed by the Advisory Board on Radiation and Worker 

Health for factual accuracy or applicability within the requirements of 42 CFR 82. 
Figure 4-17: Ratio of 84th Percentile of Uranium Samples from Construction Workers 

(CW) in Specified Work Areas over 84th Percentile of Uranium Samples from Construction 

Workers in All Work Areas, by Decade 

Figure 4-18: Ratio of GSD of Uranium Samples from Construction Workers (CW) in 

Specified Work Areas over GSD of Uranium Samples from Construction Workers 

in All Work Areas, by Decade 

SRS – Draft Review of OTIB-0075 50 SC&A – January 13, 2010 

NOTICE: This report has been reviewed for Privacy Act information and has been cleared for distribution. 

However, this report is pre-decisional and has not been reviewed by the Advisory Board on Radiation and Worker 

Health for factual accuracy or applicability within the requirements of 42 CFR 82. 
5.0 ANALYSIS OF SRS CONSTRUCTION WORKER CLAIMANT 

EXPOSURE BY CRAFT 

In addition to the variability of construction worker and non-construction workers bioassay 

samples by year and work area, the bioassay samples from construction workers also vary across 

the construction crafts. Table 5-1 shows the ratio of 84th percentile of tritium exposure for 

construction workers in the specified crafts divided by the 84th percentile for construction 

workers in all crafts. Tritium is the radionuclide examined by NIOSH for SRS in OTIB-0075. 

This ratio has the same denominator that was used in Tables 4-5 and 4-6. This ratio is a measure 

of the differences in exposure among construction workers in different crafts. Figure 5-1 shows 

a bar plot of the ratios in Table 5-1. Pipefitters have higher exposures than other crafts in all but 

the most recent decades. However, in the 1990s and 2000s, general construction workers had 

higher exposures than the pipefitters. 

Table 5-1: Ratio of 84th Percentile of Tritium Samples from Construction Workers 

in Specified Craft over 84th Percentile of Tritium Samples from 

Construction Workers in All Crafts 

Craft 1950s 1960s 1970s 1980s 1990s 2000s 

Tritium

Electrician 1.18 0.60 1.00 0.90 0.75 n/c 

Pipefitter 1.18 1.40 2.00 1.30 1.25 0.19 

Laborer 0.59 0.80 0.66 0.40 0.75 n/c 

Iron Worker 1.07 0.40 n/c n/c 0.50 n/c 

Carpenter 0.59 1.00 1.00 1.00 1.00 n/c 

Construction 0.29 1.20 0.50 0.60 1.75 1.15 

n/c: Not calculated 

Figure 5-1: Ratio of 84th Percentile of Tritium Samples from Construction Workers in 

Specified Crafts over 84th Percentile of Tritium Samples from Construction Workers in All 

Construction Crafts, by Decade 

SRS – Draft Review of OTIB-0075 51 SC&A – January 13, 2010 

NOTICE: This report has been reviewed for Privacy Act information and has been cleared for distribution. 

However, this report is pre-decisional and has not been reviewed by the Advisory Board on Radiation and Worker 

Health for factual accuracy or applicability within the requirements of 42 CFR 82. 
The ratio of the GSD for tritium samples from construction workers in the specified work area 

over the GSD for construction workers in all work areas is shown in Table 5-2. When the ratio 

of the GSDs exceeds 1, the distribution of samples from construction workers in the specified 

craft has a wider spread than the distribution for construction workers in all crafts. The plot of 

the GSD ratios in Figure 5-2 is very similar to the plot in Figure 5-1. An additional high ratio is 

observed for carpenters in the 1990s. 

Table 5-2: Ratio of GSD of Tritium Samples from Construction Workers in Specified 

Craft over GSD of Tritium Samples from Construction Workers in All Crafts 

Craft 1950s 1960s 1970s 1980s 1990s 2000s 

Tritium

Electrician 1.18 1.20 1.00 0.90 0.75 n/c 

Pipefitter 1.18 0.70 2.00 1.08 1.25 0.19 

Laborer 0.59 0.80 1.32 0.40 0.75 n/c 

Iron Worker 1.07 0.80 n/c n/c 0.50 n/c 

Carpenter 0.59 0.50 1.00 1.00 2.00 n/c 

Construction 0.29 0.60 1.00 0.60 1.75 0.57 

n/c: Not calculated 

Figure 5-2: Ratio of GSD of Tritium Samples from Construction Workers in Specified 

Crafts over GSD of Tritium Samples from Construction Workers in All Construction 

Crafts, by Decade 

FINDING #12: At SRS, the 84th percentiles of exposures to tritium for construction workers 

in specific crafts show considerable differences from the 84th percentile of exposures to all 

construction workers. Similar results are observed for the corresponding ratio of the GSDs. 

SRS – Draft Review of OTIB-0075 52 SC&A – January 13, 2010 

NOTICE: This report has been reviewed for Privacy Act information and has been cleared for distribution. 

However, this report is pre-decisional and has not been reviewed by the Advisory Board on Radiation and Worker 

Health for factual accuracy or applicability within the requirements of 42 CFR 82. 
Table 5-3 shows the ratio of 84th percentile for construction workers in the specified work area 

over the 84th percentile for non-construction workers in all work areas combined. This ratio has 

the same denominator that was used in Tables 4-3 through 4-6. This ratio measures how well 

site-wide non-construction worker data perform in estimating construction worker exposures in 

different crafts. This ratio is affected both by the differences in exposure among the construction 

crafts shown in Table 4-1 and the differences between construction workers and nonconstruction workers shown in Table 4-2. 

Figure 5-3 shows a bar plot of the differences between the 84th percentiles for each construction 

craft and the 84th percentile derived from site-wide non-construction worker data. Included in 

this plot at the left is the same ratio for all construction workers combined. Differences ranging 

from a factor of 2 to 3 are observed for most construction crafts. The NIOSH proposal would 

not be claimant favorable for construction workers in these crafts if site-wide data from nonconstruction worker claimants were used to estimate exposures for construction workers. 

Table 5-3: Ratio of 84th Percentile of Tritium Samples from Construction Workers in 

Specified Crafts over 84th Percentile of Tritium Samples from 

All Non-Construction Workers 

Craft 1950s 1960s 1970s 1980s 1990s 2000s 

Tritium

All Crafts 1.55 1.67 1.00 1.00 2.00 3.00 

Electrician 1.82 1.00 1.00 0.90 1.50 n/c 

Pipefitter 1.82 2.33 2.00 1.30 2.50 0.56 

Laborer 0.91 1.33 0.66 0.40 1.50 n/c 

Iron Worker 1.65 0.67 n/c n/c 1.00 n/c 

Carpenter 0.91 1.67 1.00 1.00 2.00 n/c 

Construction 0.45 2.00 0.50 0.60 3.50 3.44 

 n/c: Not calculated 

Figure 5-3: Ratio of 84th Percentile of Tritium Samples from Construction Workers in 

Specified Crafts over 84th Percentile of Tritium Samples from All Non-Construction 

Workers, by Decade 

SRS – Draft Review of OTIB-0075 53 SC&A – January 13, 2010 

NOTICE: This report has been reviewed for Privacy Act information and has been cleared for distribution. 

However, this report is pre-decisional and has not been reviewed by the Advisory Board on Radiation and Worker 

Health for factual accuracy or applicability within the requirements of 42 CFR 82. 
The ratio of the GSD for tritium samples from construction workers in the specified work area 

over the GSD for non-construction workers in all work areas is shown in Table 5-4. The plot of 

the GSD ratios in Figure 5-4 is very similar to Figure 5-3, but at a slightly lower level. 

Table 5-4: Ratio of GSD of Tritium Samples from Construction Workers in Specified 

Crafts over GSD of Tritium Samples from All Non-Construction Workers 

Craft 1950s 1960s 1970s 1980s 1990s 2000s 

Tritium

All Crafts 1.55 0.83 1.00 1.00 1.00 3.00 

Electrician 1.82 1.00 1.00 0.90 0.75 n/c 

Pipefitter 1.82 0.58 2.00 1.08 1.25 0.56 

Laborer 0.91 0.67 1.32 0.40 0.75 n/c 

Iron Worker 1.65 0.67 n/c n/c 0.50 n/c 

Carpenter 0.91 0.42 1.00 1.00 2.00 n/c 

Construction 0.45 0.50 1.00 0.60 1.75 1.72 

n/c: Not calculated 

Figure 5-4: Ratio of GSD of Tritium Samples from Construction Workers in Specified 

Crafts over GSD of Tritium Samples from All Non-Construction Workers, by Decade 

FINDING #13: At SRS, the 84th percentiles of exposures to tritium for construction workers 

in specific crafts show considerable differences from the 84th percentile of site-wide exposures 

for non-construction workers. Similar results are observed for the corresponding ratio of the 

GSDs. 

SRS – Draft Review of OTIB-0075 54 SC&A – January 13, 2010 

 This report has been reviewed for Privacy Act information and has been cleared for distribution. 

However, this report is pre-decisional and has not been reviewed by the Advisory Board on Radiation and Worker 

Health for factual accuracy or applicability within the requirements of 42 CFR 82. 

NOTICE:
SRS – Draft Review of OTIB-0075 55 SC&A – January 13, 2010 

NOTICE: This report has been reviewed for Privacy Act information and has been cleared for distribution. 

However, this report is pre-decisional and has not been reviewed by the Advisory Board on Radiation and Worker 

Health for factual accuracy or applicability within the requirements of 42 CFR 82. 

6.0 OVERALL CONCLUSIONS 

Our overall conclusions can be divided into two parts. The first relates to the hypothesis that 

OTIB-0075 seeks to demonstrate—that claimant data are representative of all-worker data. The 

second relates to the SRS construction worker SEC—whether the claimant database as compiled 

from NOCTS provides a satisfactory basis for a coworker model that would meet the 

requirements of dose reconstruction with sufficient accuracy. 

6.1 CONCLUSIONS REGARDING ORAUT-OTIB-0075 

We examined all three datasets in OTIB-0075. Our conclusions are as follows: 

(1) The uranium dataset for Y-12 conforms to the OTIB-0075 hypothesis of claimant data 

representativeness. 

(2) The data for Mound indicate significant differences between claimant and all-worker 

plutonium bioassay data. 

(3) The SRS tritium data cover a very narrow period from 1990 to 2001. These data show no 

significant differences 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 

from the period 1992 through 2001 again show no significant differences at the annual 

level of aggregation. 

6.2 SRS CONSTRUCTION WORKER COWORKER MODEL 

Our conclusion regarding the use of the SRS NOCTS data compiled by NIOSH for use as the 

basis for a coworker model to demonstrate the ability to reconstruct dose with sufficient accuracy 

is as follows: 

(1) A conclusion that the claimant data from the 1990s for tritium are representative of the 

claimant population can, at best, be applied to that radionuclide and that period. This 

conclusion cannot be back-extrapolated to other periods. Even within this period, there 

are differences between construction workers disaggregated by craft and nonconstruction workers. 

(2) There are considerable differences in exposures between job types and areas, even when 

data are aggregated by decade. This applies to all non-construction workers, as well as 

construction workers, when compared to others in the same group. 

(3) The data indicate that construction workers in some areas and periods had greater 

exposure potential than all non-construction workers. 

We have not analyzed certain radionuclides, like americium, neptunium-237, curium-244, and 

californium-252, since NOCTS data for construction workers are too scant for an analysis.
SRS – Draft Review of OTIB-0075 56 SC&A – January 13, 2010 

 This report has been reviewed for Privacy Act information and has been cleared for distribution. 

However, this report is pre-decisional and has not been reviewed by the Advisory Board on Radiation and Worker 

Health for factual accuracy or applicability within the requirements of 42 CFR 82. 

NOTICE:

The overall conclusion of this analysis for the SRS coworker model is that, contrary to 

NIOSH’s proposal in its Evaluation Report (NIOSH 2008), the NOCTS claimant dataset is 

inadequate for dose reconstruction with sufficient accuracy for SRS construction workers. 

A more complete compilation of the data and analyses by area, radionuclide, and job type 

are necessary to determine whether dose reconstruction with sufficient accuracy is feasible 

for SRS construction workers. 

7.0 REFERENCES 

42 CFR 83. Procedure for Designating Classes of Employees as Members of the Special 

Exposure Cohort under the Energy Employees Occupational Illness Compensation Program Act 

of 2000. On the web at http://ecfr.gpoaccess.gov/cgi/t/text/textidx?c=ecfr&tpl=/ecfrbrowse/Title42/42cfr83_main_02.tpl 

Battelle 2007. Default Assumptions and Methods for Atomic Weapons Employer Dose 

Reconstructions, Rev 0. Battelle PNWD, Battelle-TIB-5000. April 2, 2007. 

NIOSH 2008. SEC Petition Evaluation Report: Petition SEC 00103. National Institute of 

Occupational Safety and Health, November 14, 2008. 

ORAUT-OTIB-0075. Use of Claimant Datasets for Coworker Modeling, Rev. 00, Oak Ridge 

Associated Universities Team, Cincinnati, Ohio. May 5, 2009. Cited in the text as OTIB-0075 

for short. 

SC&A 2009. Issues Matrix for the Savannah River Site SEC Petition and Petition Evaluation 

Report, S. Cohen & Associates, Vienna, Virginia, September 2009. 

Watkins, J.P., J.L. Reagan, D.L. Cragle, E.L. Frome, C.M. West, D.J. Crawford-Brown, and 

W.G. Tankersley, 1993. Data Collection, Validation, and Description for the Oak Ridge 

Nuclear Facilities Mortality Study, ORISE 93/J-42, Oak Ridge Institute for Science and 

Education, Oak Ridge, Tennessee. October 1993. [SRDB Ref ID:10133]
SRS – Draft Review of OTIB-0075 57 SC&A – January 13, 2010 

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However, this report is pre-decisional and has not been reviewed by the Advisory Board on Radiation and Worker 

Health for factual accuracy or applicability within the requirements of 42 CFR 82. 

APPENDIX A: SAMPLE SIZE AND 84TH PERCENTILES OF NONCONSTRUCTION WORKER BIO-SAMPLES 
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Health for factual accuracy or applicability within the requirements of 42 CFR 82. 

Table A-1: Number of Tritium Samples from Non-Construction Workers in 

Specified Work Areas 

 Work Area 1950s 1960s 1970s 1980s 1990s 2000s 

Tritium

All Areas 19,821 53,027 50,166 46,294 17,550 1,041 

C-Area 1,611 11,505 12,113 8,141 736 [redact] 

D-Area 502 1,481 1,594 2,678 823 [redact] 

F-Area 422 124 68 24 69 [redact] 

G-Area [redact] [redact] 635 91 70 [redact] 

H-Area 517 13,592 16,302 11,063 7,524 691 

K-Area 563 5,829 8,100 9,832 5,412 25 

L-Area 967 6,072 [redact] 4,096 1,309 [redact] 

M-Area 10 12 20 10 34 [redact] 

P-Area 784 6,117 10,515 9,799 1,125 [redact] 

R-Area 1,541 5,369 [redact] [redact] [redact] [redact] 

T-Area [redact] [redact] [redact] [redact] 291 [redact] 

U-Area [redact] 568 [redact] [redact] [redact] [redact] 

CS-Area 81 998 604 [redact] [redact] [redact] 

BG - Background [redact] 118 [redact] [redact] [redact] [redact] 

None Listed 12,338 1,078 69 489 22 266 

Other 484 161 135 59 128 38 

Table A-2: 84th Percentile of Tritium Samples from Non-Construction Workers in 

Specified Work Areas (μCi/L) 

 Work Area 1950s 1960s 1970s 1980s 1990s 2000s 

Tritium

All Areas 1.1 3 2 1 0.2 0.09 

C-Area 6 5 2 1 0.1 n/c 

D-Area 2 3 3 0.8 0.3 n/c 

F-Area 4.46 0.5 n/c n/c n/c n/c 

G-Area n/c n/c 0.5 n/c n/c n/c 

H-Area 0.5 0.5 1 0.5 0.1 0.05 

K-Area 2 3 3 1.3 0.3 n/c 

L-Area 2.1 5 n/c 0.25 0.1 n/c 

M-Area n/c n/c n/c n/c n/c n/c 

P-Area 4 4 2 1 0.4 n/c 

R-Area 3 4 n/c n/c n/c n/c 

T-Area n/c n/c n/c n/c 0.05 n/c 

U-Area n/c 2 n/c n/c n/c n/c 

CS-Area n/c 0.5 0.5 n/c n/c n/c 

BG - Background n/c 0.50 n/c n/c n/c n/c 

n/c: Not calculated 
SRS – Draft Review of OTIB-0075 59 SC&A – January 13, 2010 

NOTICE: This report has been reviewed for Privacy Act information and has been cleared for distribution. 

However, this report is pre-decisional and has not been reviewed by the Advisory Board on Radiation and Worker 

Health for factual accuracy or applicability within the requirements of 42 CFR 82. 

Table A-3: Number of Plutonium Samples from Non-Construction Workers in 

Specified Work Areas 

 Work Area 1950s 1960s 1970s 1980s 1990s 2000s 

Plutonium

All Areas 2,017 4,512 5,096 3,346 3,139 334 

A-Area 174 526 619 348 46 [redact] 

F-Area 965 2,557 1,732 1,215 102 [redact] 

H-Area 683 1,104 1,825 748 88 [redact] 

K-Area [redact] [redact] 43 70 [redact] [redact] 

M-Area [redact] 41 208 60 [redact] [redact] 

 

Table A-4: 84th Percentile of Plutonium Samples from Non-Construction Workers in 

Specified Work Areas (dpm/L) 

 Work Area 1950s 1960s 1970s 1980s 1990s 2000s 

Plutonium

All Areas 0.02 0.02 0.27 0.03 0.03 0.02 

A-Area 0.01 0.02 0.02 0.03 n/c n/c 

F-Area 0.02 0.02 0.13 0.06 0.05 n/c 

H-Area 0.03 0.07 4.00 0.03 n/c n/c 

K-Area n/c n/c n/c n/c n/c n/c 

M-Area n/c n/c 0.02 n/c n/c n/c 

n/c: Not calculated 

Table A-5: Number of Uranium Samples from Non-Construction Workers in 

Specified Work Areas 

 Work Area 1950s 1960s 1970s 1980s 1990s 2000s 

Uranium

All Areas 1,533 2,679 3,030 553 31 [redact] 

A-Area 224 265 282 69 [redact] [redact] 

F-Area 585 1,936 1,855 292 [redact] [redact] 

H-Area 189 94 30 [redact] [redact] [redact] 

M-Area 435 288 599 132 22 [redact] 

Table A-6: 84th Percentile of Uranium Samples from Non-Construction Workers in 

Specified Work Areas (dpm/L) 

 Work Area 1950s 1960s 1970s 1980s 1990s 2000s 

Uranium

All Areas 0.24 0.25 1.67 1.67 n/c n/c 

A-Area 0.12 0.25 1.67 n/c n/c n/c 

F-Area 0.23 0.36 1.67 1.67 n/c n/c 

H-Area 0.20 n/c n/c n/c n/c n/c 

M-Area 0.30 0.25 1.67 1.67 n/c n/c 

n/c: Not calculated 
SRS – Draft Review of OTIB-0075 60 SC&A – January 13, 2010 

NOTICE: This report has been reviewed for Privacy Act information and has been cleared for distribution. 

However, this report is pre-decisional and has not been reviewed by the Advisory Board on Radiation and Worker 

Health for factual accuracy or applicability within the requirements of 42 CFR 82. 

Table A-7: Number of Enriched Uranium Samples from Non-Construction Workers in 

Specified Work Areas 

 Work Area 1950s 1960s 1970s 1980s 1990s 2000s 

Enriched Uranium

All Areas 18 1,170 1,639 1,244 417 [redact] 

A-Area [redact] 81 130 56 [redact] [redact] 

F-Area [redact] 352 173 54 11 [redact] 

H-Area 10 492 201 290 29 [redact] 

M-Area [redact] 216 1,003 726 32 [redact] 

Table A-8: 84th Percentile of Enriched Uranium Samples from Non-Construction 

Workers in Specified Work Areas (dpm/L) 

 Work Area 1950s 1960s 1970s 1980s 1990s 2000s 

Enriched Uranium

All Areas n/c 0.33 2.00 1.00 0.67 n/c 

A-Area n/c n/c 0.33 n/c n/c n/c 

F-Area n/c 0.33 0.50 n/c n/c n/c 

H-Area n/c 0.33 0.33 0.67 n/c n/c 

M-Area n/c 3.17 3.65 1.00 n/c n/c 

n/c: Not calculated 

Table A-9: Number of Fission Product Samples from Non-Construction Workers in 

Specified Work Areas 

 Work Area 1950s 1960s 1970s 1980s 1990s 2000s 

Fission Products

All Areas 981 1,816 147 1,137 [redact] [redact] 

A-Area 163 274 [redact] 88 [redact] [redact] 

F-Area 452 940 22 110 [redact] [redact] 

H-Area 279 458 17 126 [redact] [redact] 

M-Area [redact] 27 [redact] 13 [redact] [redact] 

Table A-10: 84th Percentile of Fission Product Samples from Non-Construction Workers 

in Specified Work Areas (dpm/L) 

 Work Area 1950s 1960s 1970s 1980s 1990s 2000s 

Fission Products

All Areas 20 33.33 740 740 n/c n/c 

A-Area 20 33.33 n/c n/c n/c n/c 

F-Area 20 33.33 n/c 740 n/c n/c 

H-Area 20 33.33 n/c 740 n/c n/c 

M-Area n/c n/c n/c n/c n/c n/c 

n/c: Not calculated 
SRS – Draft Review of OTIB-0075 61 SC&A – January 13, 2010 

NOTICE: This report has been reviewed for Privacy Act information and has been cleared for distribution. 

However, this report is pre-decisional and has not been reviewed by the Advisory Board on Radiation and Worker 

Health for factual accuracy or applicability within the requirements of 42 CFR 82. 

APPENDIX B: SAMPLE SIZE AND 84TH PERCENTILES OF 

CONSTRUCTION WORKER BIO-SAMPLES 
SRS – Draft Review of OTIB-0075 62 SC&A – January 13, 2010 

NOTICE: This report has been reviewed for Privacy Act information and has been cleared for distribution. 

However, this report is pre-decisional and has not been reviewed by the Advisory Board on Radiation and Worker 

Health for factual accuracy or applicability within the requirements of 42 CFR 82. 

Table B-1: Number of Tritium Samples from Construction Workers in 

Specified Work Areas 

 Work Area 1950s 1960s 1970s 1980s 1990s 2000s 

Tritium

All Areas 1,203 6,687 1,355 4,519 3,499 61 

C-Area 45 1,141 434 571 43 [redact] 

F-Area 71 [redact] [redact] [redact] [redact] [redact] 

H-Area [redact] 1,087 288 419 625 35 

K-Area 76 1,432 343 1,650 1,147 [redact] 

L-Area 126 1,155 [redact] 957 664 [redact] 

P-Area 97 1,219 273 859 956 [redact] 

R-Area 91 480 [redact] [redact] [redact] [redact] 

None Listed 598 70 [redact] 27 [redact] 16 

Other 93 98 [redact] 31 58 [redact] 

Table B-2: 84th Percentile of Tritium Samples from Construction Workers in 

Specified Work Areas (μCi/L) 

 Work Area 1950s 1960s 1970s 1980s 1990s 2000s 

Tritium

All Areas 1.7 5 2 1 0.4 0.27 

C-Area 3 6 2 1 0.05 n/c 

F-Area 3.34 n/c n/c n/c n/c n/c 

H-Area n/c 0.5 0.5 0.5 0.05 0.3 

K-Area 5 3 2 1.5 0.5 n/c 

L-Area 1 6 n/c 0.25 0.2 n/c 

P-Area 6 6 2 1.1 0.6 n/c 

R-Area 0.50 5 n/c n/c n/c n/c 

n/c: Not calculated 
SRS – Draft Review of OTIB-0075 63 SC&A – January 13, 2010 

NOTICE: This report has been reviewed for Privacy Act information and has been cleared for distribution. 

However, this report is pre-decisional and has not been reviewed by the Advisory Board on Radiation and Worker 

Health for factual accuracy or applicability within the requirements of 42 CFR 82. 

Table B-3: Number of Plutonium Samples from Construction Workers in 

Specified Work Areas 

 Work Area 1950s 1960s 1970s 1980s 1990s 2000s 

Plutonium

All Areas 47 201 161 398 489 44 

A-Area [redact] 17 44 13 [redact] [redact] 

F-Area 25 69 53 112 [redact] [redact] 

H-Area 11 28 27 63 [redact] [redact] 

CS-Area [redact] 46 15 38 12 [redact] 

Table B-4: 84th Percentile of Plutonium Samples from Construction Workers in 

Specified Work Areas (dpm/L) 

 Work Area 1950s 1960s 1970s 1980s 1990s 2000s 

Plutonium

All Areas 0.02 0.03 0.03 0.06 0.03 0.02 

A-Area n/c 0.03 0.03 0.03 n/c n/c 

F-Area 0.02 0.03 0.03 0.06 n/c n/c 

H-Area 0.02 0.03 0.06 0.07 n/c n/c 

CS-Area n/c 0.03 0.03 0.07 0.11 n/c 

n/c: Not calculated 

Table B-5: Number of Uranium Samples from Construction Workers in 

Specified Work Areas 

 Work Area 1950s 1960s 1970s 1980s 1990s 2000s 

Uranium

All Areas 26 39 111 61 [redact] [redact] 

A-Area [redact] [redact] [redact] [redact] [redact] [redact] 

F-Area [redact] 14 61 13 [redact] [redact] 

H-Area [redact] [redact] [redact] [redact] [redact] [redact] 

M-Area 10 21 48 44 [redact] [redact] 

Table B-6: 84th Percentile of Uranium Samples from Construction Workers in 

Specified Work Areas (dpm/L) 

 Work Area 1950s 1960s 1970s 1980s 1990s 2000s 

Uranium

All Areas 0.18 0.50 3.33 0.38 n/c n/c 

A-Area n/c n/c n/c n/c n/c n/c 

F-Area n/c 0.37 5.56 1.67 n/c n/c 

H-Area n/c n/c n/c n/c n/c n/c 

M-Area n/c 0.50 0.38 0.38 n/c n/c 

n/c: Not calculated 
SRS – Draft Review of OTIB-0075 64 SC&A – January 13, 2010 

NOTICE: This report has been reviewed for Privacy Act information and has been cleared for distribution. 

However, this report is pre-decisional and has not been reviewed by the Advisory Board on Radiation and Worker 

Health for factual accuracy or applicability within the requirements of 42 CFR 82. 

Table B-7: Number of Enriched Uranium Samples from Construction Workers in 

Specified Work Areas 

 Work Area 1950s 1960s 1970s 1980s 1990s 2000s 

Enriched Uranium

All Areas [redact] [redact] 22 49 95 [redact] 

A-Area [redact] [redact] [redact] [redact] [redact] [redact] 

F-Area [redact] [redact] [redact] [redact] [redact] [redact] 

H-Area [redact] [redact] [redact] [redact] [redact] [redact] 

M-Area [redact] [redact] 15 33 [redact] [redact] 

Table B-8: 84th Percentile of Enriched Uranium Samples from Construction Workers in 

Specified Work Areas (dpm/L) 

 Work Area 1950s 1960s 1970s 1980s 1990s 2000s 

Enriched Uranium

All Areas n/c n/c 0.33 1.80 0.67 n/c 

A-Area n/c n/c n/c n/c n/c n/c 

F-Area n/c n/c n/c n/c n/c n/c 

H-Area n/c n/c n/c n/c n/c n/c 

M-Area n/c n/c 0.33 0.96 n/c n/c 

n/c: Not calculated 

Table B-9: Number of Fission Product Samples from Construction Workers in 

Specified Work Areas 

 Work Area 1950s 1960s 1970s 1980s 1990s 2000s 

Fission Products

All Areas 19 70 17 327 [redact] [redact] 

A-Area [redact] [redact] [redact] 11 [redact] [redact] 

F-Area [redact] 35 [redact] 60 [redact] [redact] 

H-Area [redact] 19 [redact] 48 [redact] [redact] 

M-Area [redact] [redact] [redact] 10 [redact] [redact] 

Table B-10: 84th Percentile of Fission Product Samples from Construction Workers in 

Specified Work Areas (dpm/L) 

 Work Area 1950s 1960s 1970s 1980s 1990s 2000s 

Fission Products

All Areas 25.88 25.00 740 652.54 n/c n/c 

A-Area n/c n/c n/c 740 n/c n/c 

F-Area n/c 26.63 n/c 649.53 n/c n/c 

H-Area n/c 22.29 n/c 577.46 n/c n/c 

M-Area n/c n/c n/c n/c n/c n/c 

n/c: Not calculated 
SRS – Draft Review of OTIB-0075 65 SC&A – January 13, 2010 

NOTICE: This report has been reviewed for Privacy Act information and has been cleared for distribution. 

However, this report is pre-decisional and has not been reviewed by the Advisory Board on Radiation and Worker 

Health for factual accuracy or applicability within the requirements of 42 CFR 82. 

APPENDIX C: SAMPLE SIZE AND 84TH PERCENTILES OF 

CONSTRUCTION WORKER TRITIUM BIO-SAMPLES BY CRAFT 
SRS – Draft Review of OTIB-0075 66 SC&A – January 13, 2010 

 This report has been reviewed for Privacy Act information and has been cleared for distribution. 

However, this report is pre-decisional and has not been reviewed by the Advisory Board on Radiation and Worker 

Health for factual accuracy or applicability within the requirements of 42 CFR 82. 

NOTICE:

Table C-1: Number of Tritium Samples from Construction Workers in 

Specified Construction Crafts 

Craft 1950s 1960s 1970s 1980s 1990s 2000s 

Tritium

All Crafts 1,203 6,687 1,355 4,519 3,499 61 

Electrician 377 2,591 771 1,386 1,096 [redact] 

Pipefitter 266 1,645 238 1,301 1,256 34 

Laborer 90 448 24 316 268 [redact] 

Iron Worker 33 406 [redact] [redact] 137 [redact] 

Carpenter 35 523 98 647 132 [redact] 

Construction 402 1,074 215 863 610 26 

Table C-2: 84th Percentile of Tritium Samples from Construction Workers in 

Specified Construction Crafts (μCi/L) 

 Work Area 1950s 1960s 1970s 1980s 1990s 2000s 

Tritium

All Crafts 1.7 5 2 1 0.4 0.27 

Electrician 2 3 2 0.9 0.3 n/c 

Pipefitter 2 7 4 1.3 0.5 0.05 

Laborer 1 4 1.32 0.4 0.3 n/c 

Iron Worker 1.82 2 n/c n/c 0.2 n/c 

Carpenter 1 5 2 1 0.4 n/c 

Construction 0.50 6 1.00 0.60 0.70 0.31 

 n/c: Not calculated