National Institute for Occupational Safety and Health

Savannah River Site Subcontractor 

Monitoring Update

Timothy D. Taulbee, PhD, CHP

Research Health Scientist

Advisory Board on Radiation and Worker Health (ABRWH) Meeting

Albuquerque, New Mexico | December 13, 2017
Overview

 NIOSH / SC&A Subcontractor Analysis

 NIOSH concerns with SC&A Subcontractor Monitoring Report

– 30 / 90 day criteria

– Re-evaluation of SC&A Data

– NOCTS Subcontractor Monitoring Data

– 10 CFR 835 Internal Monitoring and SRS Monitoring Program

– Review of the 10 CFR 830 Notice of Violation (NOV)

 Status of Issues
Re-Cap NIOSH Job Plan Analysis

 Evaluated Job-Plans that required respiratory use

– 68% of subcontractors have direct monitoring data

– 92% of the subcontractors have either direct monitoring or a coworker on the same RWP was monitored

 NIOSH concluded that a Co-worker model would be sufficiently 

accurate

– Evaluated for bias and other considerations
SC&A Subcontractor Report - Overview

 SC&A full analysis of all RWPs in the 1990s found:

– 30 day post RWP (201/306) – 66% compliance rate

– 90 day post RWP (244/306) – 80% compliance rate

 When RWP specifically indicated Bioassay

– 30 day post RWP (140/197) – 71% compliance rate

– 90 day post RWP (166/197) – 84% compliance rate
NIOSH Review of SC&A Report

 Use of 30 day and 90 day criteria for bioassay

– 30 day is appropriate for tritium

• 100 mrem tritium dose still detectable after 70 days 

– Per procedure, annual monitoring was usually the requirement for 

non-tritium (actinide samples) thus SC&A excluded a significant 

number of monitored subcontractors from their analysis and 

indicated they were not monitored when in fact they were 

monitored. 

 A more fitting analysis would divide bioassay data into tritium and nontritium categories and used appropriate time interval for each category
1990s SRS Radiological Work Control and Bioassay 

Monitoring

 Worker attends Rad Worker II training

 Worker signs into RWP

 Worker checks the bioassay codes on the 

Radiological Qualifications Badge (RQB) against 

the RWP requirements for bioassay

 Worker conducts their work

– Worker leaves bioassay based on either

routine schedule or job-specific requirement 

SRDB# 167850

Bioassay Codes

Pu-02 (Plutonium 2/yr)

EU-02 (Enriched Uranium, (2/yr)

Sr-90 (Strontium-90, 1/yr)
Bioassay 

Monitoring

Box 1 SRDB# 167757

Box 2

SC&A evaluation jumps from 

Box 1 to Box 2 and checks to 

see if they have a sample 

within 30 or 90 days of sign 

in date

If a subcontractor was not 

scheduled to leave a sample 

for another 100 days there 

won’t be a sample but 

worker was monitored. A significant fraction if not majority were monitored via 

routine based on their Radiation Qualification Badge (RQB)
NIOSH Re-evaluation of SC&A Report data – Tritium

 NIOSH Re-evaluation

– 108/119 (90.8%) subcontractors on RWPs that have potential for 

tritium exposure have bioassay data

– Mean number of days between RWP and bioassay 7.5 days

– 89.2% on routine prescheduled monitoring (T-30)

– 117/119 (98%) covered by either personal data or a co-worker 

working on the same RWP had a sample
NIOSH Re-evaluation of SC&A Report data – Tritium

 Since 1973 the 95th

percentile subcontractor 

tritium dose has been 

less than 100 mrem with 

a downward trend

 Since 1980 the DuPont CTWs 95th percentile tritium dose has been less 

than 100 mrem with a downward trend. 

 Conclusion tritium monitoring of subcontractors is not a dose 

reconstruction issue at SRS. 
NIOSH Re-evaluation of SC&A Report data – Non-tritium

 NIOSH Re-evaluation found 102 subcontractors on RWPs that have 

potential for plutonium exposure

– 89/102 (87.3%) have bioassay data

– Mean number of days between RWP and bioassay 125.4 days

– 80.4% on routine prescheduled monitoring

– 100/102 (98%) covered by either personal data or a co-worker who 

signed in on the same RWP has a bioassay sample 
NIOSH Evaluation of NOCTS data

 Queried NOCTS to identify workers with Construction Trades Worker (CTW) 

job titles (412 claimants) between 1991 - 1997

 Reviewed each claim to determine whether they were subcontractor or 

prime

– Removed all WSRC CTWs (formerly DuPont Construction) that were 

electricians, millwrights, and mechanics.

– Removed WSRC crane operators (canyon) and riggers who primarily 

worked in the separations area.

 Identified 371 claimants who were subcontractor CTWs between 1991 and 

1997
Distribution – by Craft

 59% are Electricians, Pipefitters, Carpenters 

and Laborers

n=88

n=371

Same relative proportions as 

craft distribution in the 1980s 

Job Plan Analysis 

(ORAUT-RPRT-0083)
NIOSH Evaluation of NOCTS data

n=32

 339/371 (91.4%) Subcontractors have some form of internal monitoring 

(non-tritium or tritium in vitro bioassay, or in vivo bioassay) during their 

work at SRS between 1991 and 1997

 Only 32 subcontractors in NOCTS have no internal monitoring data

 Of these only 4 have external monitoring indicating radiological work 

 NIOSH believes that the monitoring data from 

the 339 monitored workers can be used to 

bound the dose to the 32 (8.6%) unmonitored 

workers
NIOSH Evaluation of NOCTS Subcontractor Data

1991 1992 1993 1994 1995 1996 1997

Total Workers 348 284 250 198 181 139 112

w/ External Monitoring 321 262 229 165 149 108 89

non-H3 Bioassay 205 193 123 83 69 56 49

H3 Bioassay 173 120 90 29 21 23 21

Whole Body Count 278 233 204 152 137 88 64

w/ Internal Monitoring 308 

(95.9%)

256 

(97.7%)

224 

(97.8%)

158 

(95.8%)

142 

(95.3%)

103 

(95.4%)

82 

(92.1%)

# External Monitoring -

No Internal Monitoring 13 6 5 7 8 5 7
Details of NOCTS Internal Monitoring Data cont.

Contractor Craft 1991 1992 1993 1994 1995 1996 1997

Const Electrician No extern No extern No extern

BSRI/Elect Electrician 1 1 1 1 1

BSRI/Paint Painter 1 1 1 H3 H3 1 H3

Const Electrician H3

BSRI/Labor Laborer 1 1 WB WB WB No extern No extern

Const Heavy Equipment No extern

Const Electrician 1

BSRI/INS Insulator WB 1 WB No extern

BSRI/Pipe Pipefitter 1 1 1 1 1 1

Const Electrician 1

BSRI/Paint Painter 1 1 WB No extern

Const Electrician H3

BSRI/SIW Welder 1 1 WB H3 1

BSRI/CMR Sheet Metal 1 1 1 1 1 1

BSRI/Labor Laborer 1 1 H3 WB 1 1 1

1 = Actinide urine bioassay, H3 = Tritium urine bioassay, WB = Whole Body Count, 

No extern = No external monitoring
Comparison of Multiple Evaluations
Issue: Incomplete Subcontractor Data for co-worker

 SC&A concludes that the bioassay dataset for CTW subcontractors, specifically, and 

CTWs, generally, is demonstrably incomplete for 1989–1998 (and likely before that 

time period) and does not satisfy the criteria set forth in NIOSH’s Draft Criteria for 

the Evaluation and Use of Coworker Datasets (NIOSH 2015).

 We respectfully disagree. 

– We believe that 90.8% and 87.3% direct monitoring for subcontractors is not 

“demonstrably incomplete” and does satisfy criteria set forth in the 

Implementation Guide. 

– NOCTS data indicates that subcontractors were monitored. Evaluation 

indicates that 91.6% of the subcontractors who are claimants 1991-1997 have 

some form of internal monitoring data (in vitro and/or in vivo). 
10 CFR 835.402(c)(1) Individual Monitoring

 (c) For the purpose of monitoring individual exposures to internal 

radiation, internal dose evaluation programs (including routine bioassay 

programs) shall be conducted for:

(1) Radiological workers who, under typical conditions, are likely to receive 

0.1 rem (0.001 Sievert) or more committed effective dose equivalent, 

and/or 5 rems (0.05 Sievert) or more committed dose equivalent to any 

organ or tissue, from all occupational radionuclide intakes in a year

10CFR835 (1997)
DOE- STD-1128-98 Section 5.3.2 Monitoring 

Requirements and Selection of Employees (for 

Bioassay Program)

 Workers who are considered likely to have intakes resulting in excess of 100-mrem CEDE are 

required to participate in a bioassay program. However, because of the extensive radiological 

control practices for plutonium facilities, including a high degree of engineered barrier 

containment, no typical plutonium worker is likely to have intakes of 100-mrem CEDE or more. 

However, this should not be used as an excuse to exclude workers from routine bioassay. 

Although no one should be considered likely to have intakes resulting in 100-mrem CEDE, 

some workers are at significantly higher risk for incurring an intake than others and should be 

on routine bioassay.

 This is the standard today 

– (original June 1998, reaffirmed May 2003, small changes Feb 2005)
Radiological Control - Defense in Depth 

 SRS used a Defense in Depth approach to Radiological control with the 

intention to prevent non-tritium intakes (SRDB# 167851)

1. Policy (zero intake policy)

2. Engineered Controls

3. Procedural Controls

4. Personnel Protective Equipment (PPE)

5. Surveillance used to verify Engineering, Procedural, and PPE

• Air Monitoring

• Facility Contamination Surveys

• Personnel Contamination Surveys

• Routine Bioassay
10 CFR 830 Notice of Violation - Follow-up Data 

Requests

 NIOSH requested information from both DOE-HQ and SRS regarding this 

violation to learn more information

– SRS provided over 1000 pages of information

– DOE-HQ provided just the final NTS report (8 pages) and indicated that they 

did not retain any other information related to this violation

 NIOSH sent a follow-up request to SRS on Sept 2017 specifically requesting 

internal assessments in 1994, 1995, 1996 and 1997 that were listed in the 

NTS report as well as other documents. 

– Due to funding issues SRS has been delayed in looking for these 

assessments. The site is currently working on locating the 

information.
DOE Notice of Violation – 10 CFR 830.120 

 10 CFR 830.120(c)(2)(i) requires that work be performed to established 

administrative controls using approved procedures.

 10 CFR 830.120(c)(1)(iii), Quality Improvement, requires that (1) processes 

to detect and prevent quality problems be established and implemented; 

(2) that items, services and processes that do not meet established 

requirements be identified, controlled and corrected according to the 

importance of the problem and the work affected; and (3) that correction 

shall include identifying the causes of problems and working to prevent 

recurrence. SRDB# 167497
DOE Notice of Violation 10 CFR 830.120(c)(2)(i)

 However, between January 1, 1996, and September 20, 1997, WSRC Facility

Evaluation Board reports identified that (1) workers were on incorrect bioassay 

programs, as identified by their RQB and consequently did not submit job-specific 

bioassay samples as required; (2) line management did not always ensure that 

new employees were placed on the correct bioassay schedule, the Bioassay 

Schedule Report was not always provided to line management for accuracy review, 

and job-specific bioassay sampling requirements were not always identified on 

RWPs; and (3) bioassay assignments were not always reviewed when personnel 

received an annual whole body count.

 This violation constitutes a Severity Level II problem.

 Civil Penalty - $37,500
DOE Notice of Violation – incorrect bioassay 

 WSRC Facility Evaluation Board reports identified that (1) workers were on 

incorrect bioassay programs, as identified by their RQB and consequently did not 

submit job-specific bioassay samples as required;

 Corrective Action

– SRS sent 4000 form letters on February 19, 1998 and mailed them to every site 

employee and subcontractor currently on a routine bioassay program asking 

them to compare the bioassay codes on their RQB and those listed in the 

letter. (ESH-HPT-98-0134) (SRDB# 167757, p. 49)

– Less than 100 discrepancies were identified (< 2.5%). 
DOE Notice of Violation 10 CFR 830.120(c)(1)(iii)

 Contrary to the above, processes to detect and prevent quality problems were not 

adequately established and implemented and corrective actions did not prevent 

recurrence in that in November 1995, DOE identified to WSRC that radiation work 

permit-prescribed bioassay sampling requirements were not effectively 

implemented in that 23 percent of workers did not submit bioassay samples as 

required. Corrective actions were implemented by WSRC. However, the corrective 

actions were not effective to prevent recurrence in that non-participation by 

radiation workers in the job-specific portion of the bioassay program continued 

through 1996 and increased to a level of non-participation of 79 percent by the 

second quarter of 1997.

 This violation constitutes a Severity Level II problem.

 Civil Penalty - $37,500 SRDB# 167497
SC&A “...chronic history of wide noncompliance...” 

 Nov 1995 to July 1997 is 26 months

 Three data points in this time period

– Nov 1995 – 77% participation

– April 1997 – 33% participation

– July 1997 – 21% participation

 This is just the Job-Specific 

component of the surveillance 

monitoring
Routine Bioassay

– Used to a check to verify effectiveness of procedural and engineered 

controls

– Trigger for-cause bioassay programs

– Requested from workers who have a reasonable potential for intakes 

but who SRS was confident did not have intakes in excess of 2% of the 

annual limit SRDB# 167851

 “WSRC further stated that the workers themselves were the last line of 

defense in the workplace indicator program which was the reason why a 

confirmatory program for workers was conducted.” (SRDB# 167497)
“Expected” 

Monitoring

This is what SRS thought 

was happening

SRDB# 167757
Actual 

Subcontractor 

Monitoring

SRDB# 167757

95%

5%

3.35%

1.65%

96.65%

95%

Limited assessment of 3200 

bioassay requirements –

33% compliance on Job 

specific bioassay

Full assessment of ????

bioassay requirements –

“about 21% compliance” on 

Job specific bioassay

1997 Total # of samples 

NOT received was 256 107 Samples

3200 Samples

3092 Samples

67%

33%
SRS Bioassay Monitoring (Routine Actinide Samples)

 Table indicates very 

good radiological 

control to prevent 

actinide intakes

 SRS internal 

dosimetrist also 

indicated that 

bioassay was final 

confirmation that 

controls were 

working. SRDB# 167851

1996 1997 1998 

(mid July)

Number of Samples

Requested 8132 9389 5251

Number of Samples 

Received

8062 

(99.1%)

9053 

(96.4%)

4864 

(92.6%)

Number Initially 

Positive

79

(0.98%)

105

(1.2%)

82

(1.7%)

Number of 

Confirmed Intakes

2

(0.025%)

2

(0.022%) 0
SRS Bioassay Monitoring (Job Specific Actinide Samples)

 Total number of samples 

requested at SRS in 1997

9389 Routine (86%)

+ 1500 Job Specific (14%)

10889 total samples

 256 workers were initially 

missed under the Job 

Specific sampling and 

required follow-up

 Follow-up indicated that 

none received an intake

1997 1998 

(mid July)

Number of Samples

Requested

1500 

(approx.)

564

Number Positive 0 0

Number of 

Confirmed Intakes 0 0

SRDB# 167851
SRS Bioassay Monitoring (Special Actinide Monitoring)

 These samples were 

taken “for cause”

 Surveillance 

(workplace indicators) 

indicated that 

something happened 

and triggered a 

concern

1996 1997 1998 

(mid July)

Number of Samples

Requested 134 249 100

Number of Samples 

Received 134 249 100

Number of 

Confirmed Intakes

9

(6.7%)

6 >100mrem

3

(1.2%)

2 >100mrem

0

SRDB# 167851
Implications for Dose Reconstruction under EEOICPA

 NIOSH respectfully disagrees with SC&A’s conclusion that this notice of 

violation would prohibit dose reconstruction of subcontractor 

construction trades workers.

– The job-specific bioassay in conjunction with the routine monitoring 

was used for surveillance to confirm adequacy of workplace 

monitoring and controls. 

– Routine or prescheduled bioassay monitoring was the primary method 

of bioassay surveillance as indicated by the large number of workers 

on routine bioassay compared to job-specific bioassay 

– The number of intakes at the site is very low (less than 0.1%) in this 

time period
Implications for Dose Reconstruction under EEOICPA

 DOE acknowledged rigorous radiological control program during 

enforcement meeting

“DOE is aware that, for all radionuclides other than tritium, the WSRC internal 

dosimetry program does not knowingly permit any worker to be exposed to 

airborne radioactive material. Further, it is noted that WSRC has implemented a 

rigorous program for the comprehensive use of field indicators during work 

activities to signal that an unexpected radiological condition may have led to 

potential occupational intakes of radioactive material by a worker.“ 

Nonetheless, DOE also appreciates that the potential exists to overlook worker 

exposures to radioactive material due to unrecognized field conditions or other 

types of personnel error. (SRDB 167497)
Implications for Dose Reconstruction under EEOICPA

 With the follow-up sampling of the 256 workers conducted by the site, 

there is no missing bioassay in 1997 regardless of the initial 67% nonparticipation rate under the “limited assessment” and 79% 

nonparticipation rate under the “full assessment”. 

– There is NO effect on the co-worker model for 1997 as all of the worker 

data has been collected and evaluated. 

– There were no intakes of radioactive material 

 The site evaluated the potential for those who may be missing samples in 

1996 and concluded that they did not have a potential for intake. (SRDB# 167497) 
Implications for Dose Reconstruction under EEOICPA

 There is no evidence that subcontractors were primarily or only monitored via jobspecific bioassay that would bias a co-worker model. 

 Even if a larger percentage of subcontractors used the job-specific bioassay 

compared to WSRC employees (CTWs or Operations), a larger fraction of 

subcontractor Construction Trades Workers (CTWs) were monitored via routine 

bioassay (Job Plan Analysis, SC&A Re-analysis, NOCTS analysis).

 Recall NOCTS data used in dose reconstructions indicates that over 90% of the 

subcontractors have some form of internal monitoring between 1991 and 1997

 The 10CFR830 violation effects both CTWs (WSRC and Subcontractor) as well as 

operations workers (WSRC)
Implications for Dose Reconstruction under EEOICPA

 Significant workplace and individual monitoring information through the 

surveillance to support that there was no internal dose that went 

undetected. 
# Actinide intakes per year

Data from SRDB# 168368
History of SRS Internal Exposures

Data from SRDB# 168368
Conclusion

 NIOSH concludes that dose reconstruction is feasible and sufficiently 

accurate through the use of a co-worker model for those that did not 

leave a bioassay sample or have any internal monitoring.

– Individual data can be used to estimate personal dose for missing data 

in previous years without needing a co-worker model. 

– For those with no internal monitoring data, NIOSH believes that the 

monitoring data from the 339 internally monitored subcontractor 

coworkers could be used to bound the dose to the 32 (8.6%) 

unmonitored subcontractor workers
Open Workgroup Issues to Resolve

1. Workers who performed work at SRS under RWP-required job-specific 

bioassays have substantially incomplete monitoring data – intakes may 

have occurred and missed for transient subcontractors.

– 1a) NIOSH Evaluate to determine if there is a subset of the SRS workforce 

(operations, WSRC Construction, Subcontractor Construction) that 

predominately uses job-specific bioassay? Potential Needs: Facility Evaluation 

Board reports (FEB). SRS is working on locating the reports requested in 

September 2017 (initial funding issues resolved in October)

– 1b) NIOSH evaluate transient subcontractors bioassay data in NOCTS and 

compare to routine subcontractors bioassay data for a potential bias. – Active 

Evaluation underway
Open Workgroup Issues to Resolve

2. RWP jobs often differed by source terms and potential exposure from 

routine work; routine monitoring data should not be used as a surrogate 

for missing RWP monitoring data.

– In abeyance 

Issue to be further discussed
Open Workgroup Issues to Resolve

3. Based on NIOSH comparisons of maximum possible 95th percentile dose 

distributions of SRS plutonium bioassay for DuPont CTWs and 

subcontractor CTWs, results indicate a number of years (in 1970s-1980s) 

where subcontractor Pu bioassays are 2-5 times higher than DuPont 

CTWs. This corresponds with interviews with subcontractor CTWs who 

indicate that they were called in for contaminated work to save the 

exposure of onsite CTWs. 

– NIOSH will provide a more comprehensive analysis of these data, 

which will include consideration of how NIOSH develops inhalation 

intake models under EEOICPA. 
DuPont CTW vs. Subcontractor CTW - Bias

 Difficulty comparing DuPont CTWs vs Subcontractor CTWs is that the 

majority of the data is below the censoring level of 0.1 dpm/day (nondetects)
DuPont CTW vs. Subcontractor CTW - Bias

 Extracted 

uncensored data 

from the Pu 

bioassay 

logbooks for 

comparison

n=99 n=25 n=116 n=74 n=72 n=83

Reporting Level
Open Workgroup Issues to Resolve

5. In terms of SRS coworker model development, NOCTS claimant dataset 

likely inadequate for dose reconstruction with sufficient accuracy for SRS 

construction workers. OTIB-0075 issues identified in 2010; stratification 

tests yet to be performed.

– Since this is primarily a co-worker issue regarding ORAUT-OTIB-0081, 

which already stratifies the workforce into Operations versus 

Construction Trades Workers (CTWs), SC&A to review/reconsider 

comment and provide feedback to the SRS Workgroup.
Open Workgroup Issues to Resolve

6. Workers in some SRS facilities were apparently unmonitored for Am-241 

due to inadequate source term characterization; other radionuclides may 

have been missed due to inadequate facility characterization process.

– SC&A to provide report to workgroup detailing concern such that the 

workgroup and NIOSH can review for potential impact on monitoring 

methods.
Open Workgroup Issues to Resolve

7. Timeframe of monitoring gap unclear before 1997, as is worker cohort 

affected by lack of job-specific bioassays.

– Due to limited assessment data in 1995 and 1997, NIOSH requested 

Facility Evaluation Board reports in 1994, 1995, 1996, and 1997 in 

September 2017. Upon receipt of these reports, NIOSH will evaluate 

the extent of this issue.