Initial Response to NIOSH Response 

Paper for ORAUT-RPRT-0092, Savannah 

River Site, 1991–2007

Bob Barton, CHP

Ron Buchanan, PhD, CHP

Joe Fitzgerald, MS, MPH

Advisory Board on Radiation and Worker Health, Savannah 

River Site Work Group

March 22, 2023
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SRS status: SEC-00103 review

 July 12, 2021: Board recommendation of SEC class for 

subcontractors, 1972–1990 (Oct. 12, 2021: Federal Register

designation date).

 April 22, 2022: SC&A issued “Focused Review of ORAUTRPRT-0092, Revision 00, and Remaining Petition SEC-00103 

Evaluation Report Period: 1991–2007.” 

 Nov. 22, 2022 (SC&A receipt: Jan. 5, 2023): NIOSH issued 

response to SC&A’s focused review.
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Designated SEC, 1972–1990

 ABRWH recommendation letter, July 12, 2021:

– “All construction trade employees of Department of Energy 

subcontractors [excluding employees of the following prime contractors 

who worked at the Savannah River Site in Aiken, South Carolina, 

during the specified time periods: E. I. du Pont de Nemours and 

Company, October 1, 1972, through March 31, 1989; and 

Westinghouse Savannah River Company [WSRC], April 1, 1989 

through December 31, 1990], who worked at the Savannah River Site 

from October 1, 1972 through December 31, 1990, for a number of 

work days aggregating at least 250 work days, occurring either solely 

under this employment or in combination with work days within the 

parameters established for one or more other classes of employees 

included in the Special Exposure Cohort.”
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ABRWH SEC basis (1972–1990)

 ABRWH recommendation letter, July 12, 2021:

– “Subcontractor construction trades workers [CTWs] conducted a broad 

range of work activities . . . . They may have worked in highcontamination and high-airborne radioactivity areas and may have 

been utilized for short-term high-exposure work tasks.”

– “Subcontractor [CTWs] may have been ‘transient’ and not have worked 

for long periods at SRS and also may have been intermittently tasked 

with nonroutine radiological jobs under work permits, and thus were not 

likely enrolled in the routine (including termination) bioassay monitoring 

program.”
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ABRWH SEC finding (1972–1990)

 ABRWH recommendation letter, July 12, 2021:

– “The Board finds there to be insufficient information, including a 

lack of job-specific radio-bioassay monitoring data for 

subcontractor construction trades workers, and assurance of 

workplace monitoring and source term data, to enable NIOSH to 

estimate with sufficient accuracy all potential internal doses from 

radionuclides associated with fuel handling, reactor operations, fuel 

reprocessing, and/or research activities, to which the proposed class 

may have been exposed during the time period in question.” 

(emphasis added)
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When did information become “sufficient” to 

enable DR with sufficient accuracy?

 Remaining SEC period for subcontractor CTWs: 1991–2007

 In its 2022 focused review, SC&A examined the following 

information for sufficiency based on prior SEC designation:

– WSRC Radiological Work Permit (RWP) and job-specific bioassay 

policies, procedures, and practices, and their implementation (trending 

numbers, percentages)

– Assurance of workplace monitoring (data completeness: degree to 

which job-specific bioassays submitted)

– Representativeness of scope and “matching” of radionuclides in RPRT0092 sampling
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Conclusion 1: Sampling premise is not sufficiently 

grounded in historical SRS practices

SC&A 2022 review

 Measured against the review criteria 

used by SC&A’s review of RPRT0092, the sampling premise is not 

sufficiently grounded in actual WSRC 

policies, procedures, and practices 

within the time period 1991–1998.

NIOSH 2022 response

 Transition between SRS operating 

contractors led to increasing RWP 

job-specific bioassays, due to 

reliance on procedures vs. RWP 

forms. Use of RWP forms with 

bioassay checklists lagged behind 

procedure-based bioassay 

collections in early 1990s; no 

evidence of RWP or bioassay 

inadequacy.

 Absence of bioassay requirements 

on RWPs “irrelevant.” (emphasis 

added)
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Conclusion 1: SC&A 2023 initial response

 RWPs not implemented by WSRC procedure until late 1992.

 “Demonstrable implementation” of RWP/job-specific bioassay 

requirements not apparent in workplace until 1994–1995. 

 RWP requirements for bioassay only evaluative marker for jobspecific bioassay performance, in face of SRS history of 

nonconformance with its own RWP and job-specific bioassay 

procedures.
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Conclusion 2: Results for direct and effective 

monitoring may be overstated

SC&A 2022 review

 NIOSH did not address all the 

radionuclides listed in the 

RWPs when determining data 

completeness for job-specific 

bioassay monitoring.

 Therefore, the percentage of 

matching results for direct and 

effective monitoring appear to 

be overstated in the RPRT- 0092 summary in section 6.3.

NIOSH 2022 response

 NIOSH agrees that they did not 

address all radionuclides but 

has updated those tallies in this 

response.

 NIOSH contends that their 

conclusion has not changed: 

A co-exposure model can still 

be constructed.
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Conclusion 2: SC&A 2023 initial response

 NIOSH’s 2022 response provides a summary analysis of their 

updated tallies and weighted point estimates (table 5). 

 The values in table 5 are very similar to SC&A’s values in 

tables 3 and 4 of SC&A’s 2022 review.
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Conclusion 3: Generalized matching is not 

sufficient

SC&A 2022 review

 SC&A found during the 1991–1998 

period that plutonium coworker matches 

were nearly 96% on the same RWPs, 

but inclusion of additional criteria 

(e.g., the same date, time, and craft) 

decreases this percentage significantly 

(down to 45%).

NIOSH 2022 response

 While not documented in RPRT-0092, 

the criteria used for a coworker match 

was a subCTW on the same RWP, same 

date, and same time. Additionally, a 

laborer could not be used as a coworker 

for another craft. 

 In summary, coworkers used for effective 

monitoring matching need only have the 

same or higher exposure potential than 

the unmonitored worker. SC&A’s criteria 

of same RWP, same date, same time, 

and same craft are far too restrictive and 

do not need to be considered when 

creating a co-exposure model.
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Conclusion 3: SC&A 2023 response

 SC&A’s 2019 review of RPRT-0092 found instances of the 

same date and/or same time criteria not met. 

 NIOSH quality assurance review may have corrected that 

condition.

 To use a coworker’s data from another craft for effective 

monitoring matching would require that it be apparent that the 

coworker’s craft had the potential to have the same or higher 

exposure potential than the unmonitored worker. 
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Conclusion 4: RWP-specified, job-specific 

bioassay data are incomplete

SC&A 2022 review

 RWP-required, job-specific bioassay data 

should be assumed to be substantially 

incomplete for purposes of demonstrating 

monitoring data completeness and 

representativeness for use in a co-exposure 

model until the end of 1996.

 A 100% resampling of all workers on job- specific bioassays was performed for 1997; 

enhanced accountability and tracking of job- specific bioassays were implemented in 

1998.

NIOSH 2022 response

 NIOSH disagrees that SRS self-assessments 

in response to regulatory issues in 1998 

indicate monitoring data incompleteness from 

a statistical standpoint or that finding 

bioassay program inadequacy is relevant to 

constructing a bounding co-exposure model. 

 If the Track database samples prescribed by 

the site internal dosimetrist when a suspected 

intake occurred are part of NIOSH’s co- exposure database, this is evidence that a 

bounding co-exposure model could be 

constructed, despite the SC&A conclusion 

that “RWP-specified, job-specific bioassay 

data are incomplete.”
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Conclusion 4: SC&A 2023 response

 If it can be demonstrated that bioassay data from “the most highlyexposed workers” are fully captured in the Track database, beginning 

sometime in 1991, that would be useful.

 However, “special” bioassays are typically for cause, to follow up 

suspected intakes via field indicators, and would not be necessarily 

representative for missed intakes. 

 Also, WSRC 1999 self-assessment found deficiencies in how personnel 

were identified for special bioassays (SRDB 167677, p. 22). 

 The only firm verification of job-specific bioassay completeness was 

performed in 1997 (79% incomplete).

 For 1991–1996, SC&A applies available fractional markers to gauge RWP 

and job-specific bioassay implementation and sees this as the best 

measure of program implementation.
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Conclusion 5: Feasibility of co-exposure model 

needs balance

SC&A 2022 review

 Feasibility of co-exposure model 

needs to balance RWP 

implementation with 

completeness of coworker data.

NIOSH 2022 response

 Accepts SC&A’s position that if 

SC&A conclusions 1–4 are 

addressed, then SC&A “would 

consider NIOSH’s conclusion 

valid . . . to support development 

of a co-exposure model.”
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Conclusion 5: SC&A 2023 response

 Conclusion 5 also included the following:

– “A conclusion about the feasibility of a co-exposure model for workers lacking 

bioassay results for nonroutine work may be reached by balancing the 

programmatic limitations of the RWPs and job-specific bioassays with the 

availability of suitable coworker bioassay data (as given in RPRT-0092).”

 SC&A believes a co-exposure model for subcontractor CTWs 

cannot be shown to be feasible unless and until data 

completeness and representativeness are demonstrated by both 

RWP-related bioassay performance and SRS procedural 

implementation.

 The lack of both figured in the designated SEC for 1972–1990. 
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Possible SEC cutoff dates for sufficiency of jobspecific bioassay data and program assurance

 1991: NIOSH finds field procedures changed to require notifications for 

suspected intakes; “Track” system cited by LaBone 

– RWP-specified bioassay = 0%, direct monitoring (DM) = 91%, 

effective monitoring (EM) = 96%

 1992: RWPs required by WSRC procedure, includes job-specific bioassays

 1994: SC&A finds listing of required bioassays on RWPs exceeds 60%; required 

listing of target radionuclides 

– RWP = 63%, DM = 73%, EM = 90%

 1996: Last year for which job-specific bioassays not verified as complete by 

WSRC (responding to 1997 self-assessment)

– RWP = 85%, DM = 75%, EM = 83%

 While the trend lines for DM and EM metrics are uneven, the upward trend for 

inclusion of bioassay requirements in RWPs is apparent and steady
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SC&A review continues

 SC&A seeks further corroboration of LaBone interview statements (NIOSH 2022, 

p. 15) about 5Q1.1-506 interpretation, “special” monitoring programs, and Track 

database, to verify inclusion of “most-highly exposed workers” in bioassay 

dataset “at some point in 1991.”

 Based on SEC designation for prior years (1972–1990), SC&A’s position 

remains that acceptable co-exposure models for subcontractor CTWs can be 

developed for post-1990 when both: 

1. RWP-required, job-specific bioassay data are shown to be sufficiently complete and 

representative for subcontractor CTWs.

2. Evidence of program adequacy is available to show WSRC assured required bioassays 

were performed and submitted.

 SC&A conclusion 5 acknowledges that an SEC cutoff date for “sufficiency of 

information” to support co-exposure model development needs to balance the 

two above considerations upon which the existing SEC designation is based for 

1972–1990.