Review of ORAUT-RPRT-0092, 

Evaluation of Bioassay Data for 

Subcontracted Construction Trade 

Workers at the Savannah River Site 

Bob Barton, Ron Buchanan, Joe Fitzgerald, SC&A 

Advisory Board on Radiation and Worker Health Meeting 

December 11, 2019, Oakland, CA
Background

 Construction subcontracted construction trade workers (subCTWs) often 

performed nonroutine jobs involving unique radiological source terms or 

conditions, and permit-required, job-specific bioassays were important to 

verify intakes.

 SC&A’s original evaluation of subCTW job-specific bioassay data found 66–84% 

completeness; concluded that RWPs before 1999 at SRS were neither complete 

nor consistently applied with respect to job-specific bioassays (SC&A, 2017).

 Further, a 1997 WSRC self-assessment found only 21% completeness and was 

contributing basis for 1998 DOE enforcement action at SRS and DOE-wide 

moratorium on compliance actions to enable corrective actions for site 

bioassay programs.

 SRS work group requested that NIOSH conduct further evaluation of subCTW 

data completeness for 1972–1998 based on recently discovered SRS permit 

records; evaluation reported in ORAUT-RPRT-0092. 

2
NIOSH RPRT-0092 Evaluation

 RPRT-0092’s sampling goal was to “randomly select radiological workers 

from various areas at [SRS]” (NIOSH, 2018c).

 Intended to “obtain an unbiased data set to evaluate subcontractor 

[bioassay] monitoring for both co-worker applicability [did monitored and 

unmonitored subCTWs work together]...and to evaluate specific 

radionuclides of interest [i.e., appropriate source term]” (Taulbee, 2018).

 Founded on similar sampling of subCTWs performed for 773-A for 1981–

1986 but focused on “other operating areas from 1972 through 1998” 

(NIOSH, 2019a)

 Diverged from Sampling Plan for 1972–1989 by not applying statistically 

based random sampling; collected all available permit/bioassay records for 

only one facility: 773-A, SRS’s analytical laboratory.

3
SC&A Review

 SC&A reviewed NIOSH’s evaluation from three vantage points:

 Sampling premise – Were guiding assumptions upon which evaluation was 

planned and conducted borne out for the time periods in question?

 Sampling execution – Did NIOSH successfully “randomly select radiological 

workers from the various areas at [SRS], such than an evaluation of monitored 

and unmonitored workers can be conducted?”

 Coworker datasets – Did the evaluation satisfy its stated objective of 

demonstrating that “monitored [subCTWs] and unmonitored [subCTWs] 

worked side by side in the same radiological environment at the same time?”

 SC&A focused its review on two distinct SRS operational periods, 1972–

1989 under DuPont, and 1990–1998 under Westinghouse.

 SC&A sought to test central thesis of RPRT-0092: Can bioassays be linked to 

corresponding work permits so that monitored subCTWs can be compared 

with unmonitored subCTWs?

4
SC&A Findings:

1. Assumption and Basis for SubCTW Data Sampling, 

1972–1989

Finding 1: No SWPs or job plans sampled by NIOSH and reviewed by SC&A for 

1972–1990 contain any requirements or indications for job-specific bioassays, 

despite respiratory protection being required, bringing into question the 

approach taken to satisfy RPRT-0092’s first evaluation objective (determining 

fraction of subCTWs identified on RWPs of interest who were monitored for 

internal intakes).

 None of SWPs reviewed for 1972–1989 have job-specific bioassay 

requirements.

 None of job plans reviewed for 1972–1989 have any indicated job-specific 

bioassay requirements, although DPSOL procedures provided for it.

 No DuPont procedures found for job-specific bioassays tied to respirator 

use.

5
SC&A Findings: Assumptions and Basis, 1972–1989 

Finding 2. “Radionuclides of interest” assumed for sampled permits in RPRT0092 are of questionable accuracy given cited lack of adequate radiological 

source term characterization prior to 1990.

 Source terms based on (by RPRT-0092 priority): work area identified on permit, SRS 

procedures for bioassay type and frequency, and 1999 Farrell and Findley 

guidelines.

 However, radionuclides rarely identified on permits, DuPont procedures relied on 

incomplete expert and experience-based bioassay tables, and 1999 guidelines 

based on facility characterization that only existed after early 1990s.

 Some SRS facilities (e.g., 773-A and waste operations) handled wide array of 

nonroutine radionuclides.

 In 1990, DOE found SRS “radiological areas have not been sufficiently characterized 

to provide a technical basis for the assignment of bioassay sample type and 

frequencies”; cited noncompliance with DOE Order 5480.11.

6
SC&A Findings: Assumptions and Basis, 1972–1989

Finding 3. Scope of permit sampling for 1972–1990 at SRS is essentially 

limited to one facility, 773-A, falling short of achieving NIOSH’s sampling 

objective and representativeness called for in NIOSH’s coworker guidelines. 

 Goal was to “randomly select radiological workers from various areas at [SRS]” and 

perform a similar statistical evaluation of subCTWs as performed for 773-A (1981–

1986), but focused on “other operating areas from 1972 through 1998” (NIOSH, 

2018c, 2019a).

 However, lack of documentation found in various data captures precluded random 

sampling and limited review (again) to just 773-A.

 Leaves out 30+ SRS major radiological facilities, e.g., canyons, tank farms, PuFF and 

PEF, ETF, RBOF, and Uranium Target Fabrication Facility, with large worker 

populations, notable contamination histories, and spectrum of source terms.

 While NOCTS may be more representative of SRS facilities and source terms, RPRT0092 evaluation is not and precludes a conclusion regarding subCTW completeness 

on a sitewide basis.

7
SC&A Findings: Assumptions and Basis, 1972–1989

Finding 4: SRS incident-based/special bioassays were provided by workers on 

a more stringent procedural basis and should not be used to supplement the 

completeness evaluation of job-specific bioassays for 1972–1989 as a 

measure of historic data completeness.

 Acknowledging lack of job-specific bioassay data for areas other than 773-A, NIOSH 

used incident reports documenting event-based bioassays as means to supplement 

its RPRT-0092 review.

 SC&A’s review of referenced incident reports confirmed many of them involved 

“special bioassays.”

 Under DuPont procedures, special bioassays were accorded particular emphasis 

and management accountability, with detailed instructions on bioassay response, 

notifications, and recordkeeping.

 Clear difference in management and procedural accountability between how 

“special” and routine bioassays handled – former should not be used to 

supplement review of the latter, if historical data completeness is being weighed.

8
SC&A Findings: Assumptions and Basis, 1972–1989

Finding 5: The incompleteness of SRS dose records for 1972–1990 is substantiated by 

the acknowledged destruction of subcontractor records and firsthand worker 

accounts, coupled with DOE findings of missing occupational radiation dose data from 

many SRS personnel files, as well as systemic bioassay delinquencies, and wide gaps in 

NIOSH’s capture of permit documentation. 

 NIOSH acknowledges that “current and former employee interviews indicated that 

some records were destroyed in the late 1980s or early 1990s,” and “the SWPs or 

Job Plans for other areas might have been destroyed as part of that effort.”

 Same interviews indicated various kinds of records were shredded, e.g., monitoring 

records and time cards, and that significant employee records gaps exist.

 DOE 1990 Tiger Team found “many personnel files where radiation dose data are 

missing for many years” and cited DuPont policy of transferring records to the 

Federal Records Repository, for which retrieval proved problematic.

9
SC&A Observation: Assumptions and Basis, 1972–1989 

Observation 1: The back application of assumptions [from the WSRC era] 

regarding work permits, job-specific bioassays, and target radionuclides to 

conduct a completeness review for 1972–1989 is not plausible given the 

significant changes in radiological policies, procedures, and practices that 

occurred in the early 1990s.

 Notable difference in how internal exposures monitored and controlled between 

DuPont and WSRC eras at SRS (e.g., 1972–1989, 1990–1998).

 DuPont operated under DOE Order 5480.1, Chapter XI, while WSRC operated under 

DOE Order 5480.11 (issued Dec. 1988, eff. Dec. 1989).

 DOE 5480.1, Chapter XI, contained general requirements for “periodic” bioassay 

analysis, whereas DOE 5480.11 introduced explicit requirements for combining 

internal and external dose equivalent, and a 100-millirem monitoring threshold, 

coupled with formal ALARA objectives and independent DOE oversight of field 

implementation.

10
Unprecedented SRS Change: 

Critical Timeline, 1988–1990

Aug. 1988: Production suspended at SRS reactors (L, K, and P, last for safety 

issues), followed by safety reviews, facility upgrades, restart 

initiatives – procedural gaps, program insularity found

April 1989: DuPont contract ends after 38 years; Westinghouse (WSRC) 

assumes role, with Bechtel managing construction

Dec. 1989: DOE Order 5480.11 implementation required; entails key 

changes to internal dosimetry monitoring and recordkeeping

Mar. 1990: Tiger Team assessment conducted at SRS by DOE/HQ team; key 

findings re bioassay, procedures, rad records compliance

mid-1990: Implementation of WSRC Radiological Improvement Plan begins, 

including “Internal Dosimetry Technical Basis Manual” and new 

WSRC radiation protection procedures, e.g., RWPs with jobspecific bioassays

11
2. Sampling Execution and Results, 1972–1989 

SC&A Adjustments to RPRT-0092 monitoring “match” criteria:

 Remove internal monitoring that was outside of acceptable 

timeframe between job plan and internal monitoring result.

 Remove identified coworker matches that involved different job 

plans (i.e., unmonitored on job plan “A” was matched to a 

monitored coworker on job plan “B”).

 Adjust “effectively monitored” population to reflect only internal 

monitoring results used in the coworker model. (Is the monitored 

coworker result actually used in the coworker model and thus 

represents the unmonitored worker?)

12
Sampling Execution and Results, 1972–1989, Americium 

 Evaluation of job-specific americium monitoring limited to 

1973 and 1981– 1987 (i.e. no job plans requiring americium 

monitoring identified for 1972, 1974–1980 or 1988–1989).

 Evaluated internal monitoring included both urinalysis and in 

vivo samples.

 Only urinalysis data is used for coworker modeling of 

americium and is therefore relevant to identifying coworker 

matches (i.e., the “effectively monitored” population).

13
Sampling Execution and Results, 1972–1989, Americium

14
 Observation 2: During the 1972–1974 period, RPRT-0092 only evaluates 

one job plan/worker combination (Job Plan 46) for potential americium 

exposure. However, attachment D, table D-1 [of RPRT-0092] indicates at 

least one other job plan (Job Plan 47) requiring americium monitoring 

during this period. Neither of the workers were directly monitored nor had 

an appropriate coworker monitored for americium.

 Observation 3: Only 13 percent of the subcontractor-job plan 

combinations (17 total) had americium urinalysis performed that could be 

considered relevant to coworker modeling. Eleven of the 17 urinalysis data 

points represented incident-driven monitoring outside the period of 

interest and in a different area.

Sampling Execution and Results, 1972–1989, Americium 

15
SC&A Findings: 1972–1989, Americium 

 Finding 6: For the period 1980–1989, only 20 percent of the identified 

subcontractor-job plan combinations identified by NIOSH as requiring 

americium sampling had internal monitoring performed within an 

acceptable timeframe (i.e., within 2 years for chest counting).

 Finding 7: The total “effectively monitored” population for americium 

(those monitored directly or have a coworker on the same job plan with a 

urinalysis result) during the 1980–1989 period is approximately 33 percent. 

If the internal monitoring related to an incident in a different SRS location 

and time period (and not currently used in the SRS coworker model) is 

removed, the effective monitored population drops to 26.5 percent. 

16
 Finding 9 [out of sequence]: SC&A does not find that the data collected as 

part of the RPRT-0092 review support the premise that subcontractors on 

job plans that should have required internal monitoring for americium 

were either directly monitored (around 20 percent) or, alternately, 

appropriately represented in the derived coworker models for SRS (around 

13 percent).

SC&A Findings: 1972–1989, Americium 

17
Sampling Execution and Results: 

1972–1974, Fission Products 

 SC&A directly monitored total (~70%) closely matches NIOSH directly 

monitored total (~74%)

 Difference due to removal of samples greater than 2 years after the job 

plan

 All fission product monitoring identified was based on urinalysis not 

in vivo, coworker model is based on in vivo monitoring

 “Effectively monitored” population remains unchanged (70%) when not 

including coworkers matched via urinalysis

 By comparison, RPRT-0092 “Effectively Monitored” total was 94%

18
Sampling Execution and Results: 

1980–1989, Fission Products 

 SC&A monitored total (~73%) closely matches NIOSH monitored total 

(~78%)

 Difference due to removal of entries greater than 2 years after the job plan 

(23 entries) and inability to verify entry in source dosimetry file (11 entries)

 Majority of fission product monitoring identified was based on urinalysis, 

not in vivo 

 “Effectively monitored” population only marginally increases to 74% when 

not including coworkers matched via urinalysis (RPRT-0092 “effectively 

monitored” total was reported as 99%)

19
SC&A Finding: 1972–1989, Fission Products

20

Finding 8: Many of the workers (around 70–73 percent) who should have 

been monitored for fission products underwent appropriate internal sampling 

during the two periods evaluated prior to 1990 (1972–1974 and 1980–1989). 

However, very few of these monitored workers underwent in vivo counting 

for fission products. Thus, they are not included in the coworker model 

developed for SRS and are not considered representative of the unmonitored 

worker. 
SC&A’s SRS Area Analysis, 1990–1998

In view of lack of representativeness of various SRS areas for 1972–1989, 

SC&A surveyed the 1990–1998 RWP data as a function of area. SC&A found:

 The RWP data were from Areas A, E, F, H, M, and G for the period 1991–

1998.

 There was only one RWP in 1990 (which was for Area F), with no 

monitored subCTWs.

21
SC&A Findings: 

3. Coworker Datasets, 1972–1998

Finding 10: Data for 1990 are lacking. Therefore, 1990 should be included 

with the period of limited data, 1972–1989, and not bundled in with the year 

1991.

 Although there were corporate changes taking place at that time, there 

was lag time in policy implantation.

 There was only one RWP with one unmonitored subCTW listed for 1990. 

 1990 should not be bundled with 1991 and treated as part of the period 

when additional data became available. 

 The time intervals should be broken up into 1972–1990 and 1991–1998, so 

that 1990 is considered in the era with very limited data.

22
SC&A Findings: All Required vs. “at least one” 

Radionuclide

Finding 11: For both the 1972–1989 and the 1990–1998 periods, when 

considering all radionuclides requiring internal monitoring per work 

permit, as opposed to “at least one radionuclide” requiring 

monitoring, the percentage of monitored workers drops significantly.

For example:

 Directly monitored workers ranged from 47% to 77% (in comparison to 

76% to 96% in RPRT-0092).

 Effectively monitored workers ranged from 55% to 89% (in comparison to 

85% to 99% in RPRT-0092). 

 Difference is particularly noticeable in the pre-1990 era.

23
SC&A Findings: Coworker Datasets, 1972–1998

Time Period RPRT-0092 

directly 

monitored for 

at least one 

radionuclide

SC&A directly 

monitored 

for all 

radionuclides 

on work permit

RPRT-0092 

effectively 

monitored 

for at least 

one 

radionuclide

SC&A 

effectively 

monitored 

for all 

radionuclides 

on work 

permit

1972–1974 76% 47.1% 85% 55%

1975–1979 No data No data No data No data

1980–1989 90% 51% 99% 66%

1990–1998 96% 77% 97% 89%

24
SC&A Observation: Coworker Datasets, 1990–1998

Observation 4: Coworker criteria - SC&A’s analysis indicates that identified 

coworker matches may not be sufficiently representative of the subCTW 

intakes in all cases unless strict criteria are applied, such as the same craft as 

well as the same date and time of the work performed.

Analysis of RPRT-0092 data indicates:

 Unmonitored subCTW and coworker were both listed on the same RWP 

96% of the time. 

 Unmonitored subCTW and monitored coworker had the same job title 60% 

of the time when signed in on the same RWP. 

 Unmonitored subCTW and coworker performed work under a given RWP 

on the same date 77% of the time. 

25
Observation 4: Coworker Criteria (continued)

 Unmonitored subCTW and coworker both signed in on the same RWP and 

same date and worked during the same time interval 66% of the time. 

 Coworkers only met all four of the required criteria 45% of the time to 

indicate a coworker and the unmonitored subCTW were working side by 

side performing similar tasks (e.g., same RWP, same craft, same date, and 

same time) to indicate similar intake potentials. 

26
SC&A Observation: Not a Step Function in 1990

Observation 5: Bioassay data in the 1990s are not entirely free of the earlier 

data issues. The implementation of methods used to correct for the bioassay 

deficiencies seen in the 1970s and 1980s did not take place immediately with 

the change in the contracting company in 1990. It was not a step function 

that took place in 1990 (only one RWP with one subCTW listed for 1990). 

Instead, it took a number of years to identify, address, and effectively 

implement the changes.... Specific radionuclides were not generally required 

on the RWPs until the mid-1990s. 

For example:

 Required plutonium bioassays on RWPs increased from 4% in 1993 to 78% 

in 1994, and to 100% in 1995.

 Required strontium and fission products bioassays on RWPs increased from 

0% in 1993 to 72% in 1994, and to 100% in 1995.

27
Other Issues

 Time span for monitoring percentages (ORAUT-RPRT-0094): “Using a three 

year span between the time of potential exposure and the time of the 

bioassay for non-tritium radionuclides significantly increases the fraction of 

monitored sCTW.... The fraction of monitored sCTW would increase for 

each year the span between employment and bioassay was increased” 

(NIOSH, 2019b).

While useful as a dose assessment consideration, applying this adjustment 

to the subCTW completeness evaluation in RPRT-0092 is inappropriate. 

NIOSH apparently agrees:

 “NIOSH considers any plutonium, uranium or fission products result obtained 

within one year of work to represent a valid internal monitoring interval” 

(NIOSH, 2018a).

 For in vivo counting: “Gaps of greater than 2 years between results are 

considered to be unmonitored” (NIOSH, 2018b).

28
Other Issues (continued)

 Soundness of SRS internal dosimetry program. SC&A’s concerns relate to 

the completeness and representativeness of job-specific bioassay data 

sitewide at SRS for 1972–1998 as they pertain to the development of a 

coworker model that satisfies NIOSH’s guidelines.

 These concerns do not extend to the overall adequacy of the SRS routine and 

special bioassay programs, the amount of related data, or the overall SRS 

radiological control record, as reflected in historical exposure statistics. 

 However, as noted, SC&A finds that radiological procedures, practices, and 

accountability were inadequate during the DuPont era (in some cases, 

extending into the WSRC period of 1990s), which bears on the subCTW data 

completeness issue. 

29
Other Issues (continued)

 How complete is complete? NIOSH claims “degree and direction of 

potential bias generated in a coworker model by missing samples is more 

important than the number of samples that were requested but not 

provided” (NIOSH, 2018a).

 However, with DuPont era job plans, evidence of followup job-specific 

bioassays is lacking. Also, with monitoring fractions often less than 50–

60% (for example), ability to demonstrate “representative” data is 

questionable.

30
Conclusions

In RPRT-0092, NIOSH concludes that “a large percentage of subCTWs were 

monitored for potential intakes while working under a Job Plan, SWP or RWP.”

 SC&A concludes that premise of RPRT-0092 evaluation is based more on 

WSRC than DuPont era practices; no evidence of standardized permitrelated bioassays required or implemented in 1972–1990.

 SRS procedures and practices for RWP-required, job-specific bioassays, 

were not defined, codified, and implemented until late 1990 under WSRC’s 

Radiological Improvement Program.

 SubCTW monitoring percentages cited by NIOSH are based on 

questionable assumptions and adjustments, leading to unfounded claims 

of bioassay monitoring “success” rates.

 Issue of bioassay completeness not confined to subCTWs; extends to all 

CTWs subject to permit-required bioassays in 1972–1990.

31
References

Farrell, W. E., & Findley, W. M. (1999, March 10). Specification of urine 

bioassay requirements on radiological work permits [Memorandum].

National Institute for Occupational Safety and Health (NIOSH). (2018a). 

Response to SC&A’s evaluation of Savannah River Site subcontractor 

bioassay data completeness, SCA-TR-2017-SEC009-SCA [Response paper]. 

January 30, 2018. 

National Institute for Occupational Safety and Health (NIOSH). (2018b). 

Internal dose reconstruction (ORAUT-OTIB-0060, rev. 02). April 20, 2018. 

National Institute for Occupational Safety and Health (NIOSH). (2018c, 

April 13). SRS work permit sampling plan.

National Institute for Occupational Safety and Health (NIOSH). (2019a). 

Evaluation of bioassay data for subcontracted construction trade workers 

at the Savannah River Site (ORAUT-RPRT-0092, rev. 00). June 14, 2019. 

32
References (continued)

National Institute for Occupational Safety and Health (NIOSH). (2019b). 

Bioassay for subcontractor construction trade workers at the Savannah 

River Site from 1972 to 1997 (ORAUT-RPRT-0094, rev. 00). September 13, 

2019.

SC&A, Inc. (2017). Evaluation of Savannah River Site subcontractor bioassay 

data completeness (SCA-TR-2017-SEC009, rev. 0), July 13, 2017.

Taulbee, T. D. (2018, April 17). SRS work permit evaluation – Path forward 

[Email communication to B. P. Clawson, Advisory Board on Radiation and 

Worker Health]. 

U.S. Department of Energy (DOE). (1990). Tiger Team assessment of the 

Savannah River Site (DOE/EH-0133).

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