Savannah River Site SEC Update 

(1991–2007)

Bob Barton, CHP

Ron Buchanan, PhD, CHP

Joe Fitzgerald, MS, MPH

Advisory Board on Radiation and Worker Health

August 16, 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) (ABRWH 2021)

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

Evaluation Report Period: 1991–2007” (SC&A 2022)

 Jan. 5, 2023: NIOSH issued response to SC&A’s focused 

review (NIOSH 2022) in January 2023 to the Board

 March 22, 2023: Work Group met via teleconference 

(ABRWH 2023)
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Designated SEC, 1972–1990

 ABRWH recommendation letter, July 12, 2021 (ABRWH 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 (ABRWH 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 (ABRWH 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 2022), 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 were 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 were not implemented by WSRC procedure until late 

1992.

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

requirements was not apparent in the workplace until 1994–

1995. 

 RWP requirements for bioassay are the only evaluative marker 

for job-specific bioassay performance, in the face of SRS’s 

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 summarizes their updated tallies and 

weighted point estimates in 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 that during the 1991–1998 

period 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 subcontractor CTW 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 RWP monitoring completeness in 

RPRT-0092 found instances of the same date and/or same 

time criteria not met. 

 NIOSH (2022) updated tallies have improved upon that 

condition.

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

monitoring matching requires that 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.

 For-cause bioassays are to follow up suspected intakes via field 

indicators and would not necessarily be representative for all missed 

intakes. 

 WSRC 1999 self-assessment found deficiencies in how personnel were 

identified for special bioassays. 

 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

 In order to establish feasibility, the 

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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Summary status of SEC issues

 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.
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Work Group path forward

 Seeks further corroboration of 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.”

 SC&A to formally reply to NIOSH 2022 response.

 SC&A to characterize the utility and feasibility of a comparison 

of available subcontractor CTW and prime CTW data.

 SC&A to evaluate captured TRACK database for applicability 

to SEC questions.
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Questions?
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References

Advisory Board on Radiation and Worker Health (ABRWH). (July 12, 2021). [Letter from H. A. 

Anderson, III, MD, Chair, to X. Becerra, Secretary, Department of Health and Human Services]. 

https://www.cdc.gov/niosh/ocas/pdfs/abrwh/secrecs/bdrecsrs-103b-508.pdf

ABRWH, Savannah River Site Work Group. (2023). Wednesday, March 22, 2023 [Transcript of 

teleconference meeting]. https://www.cdc.gov/niosh/ocas/pdfs/abrwh/2023/wgtr032223-508.pdf

National Institute for Occupational Safety and Health (NIOSH). (2022). Response to SC&A’s “Focused 

review of ORAUT-RPRT-0092, revision 00, and remaining Petition SEC-00103 evaluation report 

period: 1991–2007” [Response paper]. https://www.cdc.gov/niosh/ocas/pdfs/dps/dc-orrprt92r0-

sec103-508.pdf

SC&A, Inc. (2019). Review of ORAUT-RPRT-0092, revision 00, “Evaluation of bioassay data for 

subcontracted construction trade workers at the Savannah River Site” (SCA-TR-2019-SEC005, 

rev. 0). https://www.cdc.gov/niosh/ocas/pdfs/abrwh/scarpts/sca-srsrprt92r0-508.pdf

SC&A, Inc. (2022). Focused review of ORAUT-RPRT-0092, revision 00, and remaining Petition SEC- 00103 evaluation report period: 1991–2007 (SCA-TR-2022-SEC001, rev. 0). 

https://www.cdc.gov/niosh/ocas/pdfs/abrwh/scarpts/sca-srsorrprt92r0sec103-r0-508.pdf