National Institute for Occupational Safety and Health

Response to SC&A’s Evaluation of Savannah River Site 

Subcontractor Bioassay Data Completeness

Timothy D. Taulbee, PhD, CHP

Research Health Scientist

Meeting of the Savannah River Site Workgroup of the Advisory Board on 

Radiation and Worker Health (ABRWH)

November 2017
Overview

 SC&A Subcontractor Analysis

 NIOSH Findings / Response

– 30 and 90 day criteria

– Reanalysis of SC&A data using annual criteria for nontritium bioassay

 Evaluation of the Notice of Violation (NOV)

– Why 10CFR830 Procedural violation and not 10CFR835 

Radiological Control Violation?
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

• At the 30,000 ft level very similar to NIOSH’s findings

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

 When RWP specifically indicated Bioassay

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

• At the 30,000 ft level very similar to NIOSH’s findings

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

 Use of 30 day and 90 day criteria for bioassay

– 30 day is appropriate for tritium

• 100 mrem tritium dose detectable 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. 

 Finding 1: Bioassay Data should have been separated into tritium and 

non-tritium and appropriate time intervals used for evaluation
1st Misconception about Radiological Work Control 

and Monitoring at SRS

 If the worker was only required to leave a non-tritium sample once or 

twice a year such as plutonium, enriched uranium, strontium, then 

the 30 and 90 day criteria is not appropriate. 

 1990s Radiological work control 

– Worker attends radiological training (Rad Worker II)

– Worker signs into RWP

– Worker checks their Bioassay Codes on the Radiological 

Qualifications Card against the RWP requirements
Radiological Qualification Card (1994)

 Rad Worker II

 Whole Body count

 Chest Count (actinides)

 Bioassay Codes

– Pu-02 (Plutonium 2/yr)

– EU-02 (Enriched Uranium, 

(2/yr)

– Sr-90 (Strontium-90, 1/yr)

SRDB# 167850
2nd Misconception about Subcontractor Monitoring

 Job-Specific bioassay was NOT the only manner in which 

subcontractor construction trades workers were monitored. 

 A significant fraction were monitored via routine or prescheduled 

bioassay based on their Radiological Qualification Card 

– NIOSH will demonstrate this during our presentation on 

Subcontractor monitoring data in NOCTS
Actual 

Subcontractor 

Monitoring

SC&A report jumps from 

Box 1 to Box 2 and checks 

to see if they have a 

sample within 30 or 90 

days of sign in

If a subcontractor was not 

scheduled to leave a 

sample for another 100 

days there won’t be a 

sample. SRDB# 167757
NIOSH Reevaluation of SC&A Report Data for Tritium 

(1 of 2)

 SC&A did not break out tritium in their analysis

 NIOSH Reevaluation

– 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 Reevaluation of SC&A Report Data for Tritium 

(2 of 2)

 Since 1972 the 95th percentile 

subcontractor tritium dose 

has been less than 100 mrem 

with a downward trend

 Since 1980 the DuPont CTWs 

95th percentile dose has been 

less than 100 mrem again 

with a downward trend. 

 Conclusion tritium monitoring 

of subcontractors is not a 

dose reconstruction problem 

at SRS.
NIOSH Reevaluation of SC&A Report Data for Non-Tritium 

(1 of 2)

 Again misconceptions about the actual bioassay monitoring practice led 

SCA to exclude a significant number of samples from their analysis.

 Prescheduled non-tritium bioassay was generally conducted semiannual or annually (on or near birthdate).

– SC&A only identified 62 non-tritium bioassay

– Limited number primarily due to the exclusion of samples outside 

the 30 and 90 day time window.
NIOSH Reevaluation of SC&A Report Data for Non-Tritium 

(2 of 2)

 NIOSH Reevaluation 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
SC&A Concludes - Incomplete 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”.

– 90.8% monitoring of subcontractors for tritium

– 87.3% monitoring of subcontractors for non-tritium
Notice of Violation

 Excerpt from SC&A Report

In the course of its review, SC&A also established that a chronic history of 

wide noncompliance with job-specific bioassay requirements existed at 

SRS, resulting in a Departmental Notice of Violation being levied in 1998. 

(page 6)

 Implication is that there is inadequate workplace and worker monitoring 

for radiological hazards at SRS and therefor NIOSH cannot bound the dose 

with sufficient accuracy.

– Further implication is that this effects primarily subcontractors
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 working to compile the information now.
DOE Notice of Violation – 10 CFR830.120 

 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 jobspecific 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
NIOSH Evaluation and SC&A Evaluation Data
Notice of Violation – NIOSH Evaluation 

 Why was the a violation of 10CFR830.120 levied (procedural violation) and 

NOT a violation of 10CFR835 Radiological Control and Monitoring?

 If people were not being monitored properly that is a violation of 

– 10CFR835.401(a)(1) Monitoring of the Workplace 

– 10CFR835.402(c)(1) Individual Monitoring

SRDB# 167851
10CFR835.401(a,b) Monitoring of Workplace

 (a) Monitoring of individuals and areas shall be performed to:

(1) Demonstrate compliance with the regulations in this part;

(2) Document radiological conditions in the workplace;

(3) Detect changes in radiological conditions;

(4) Detect the gradual buildup of radioactive material in the workplace; 

(5) Verify the effectiveness of engineering and process controls in 

containing radioactive material and reducing radiation exposure.

 (b) Area monitoring in the workplace shall be routinely performed, as 

necessary, to identify and control potential sources of personnel exposure to 

radiation and/or radioactive material.

10CFR835 (1997)
10CFR835.402(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)
During Enforcement Conference on July 28, 1998 

 WSRC described the purpose of its bioassay sampling program

 WSRC stated it had a formal, no intake policy for radionuclides, other than 

tritium, and that along with its formalized workplace indicators program, 

including air sampling and contamination surveys, were the primary 

means of determining whether a worker required bioassay sampling 

outside of the routine bioassay program. For these cases, special bioassay 

sampling was performed.

SRDB# 167497
Radiological Control - Defense in Depth 

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

intention to prevent non-tritium intakes

– Policy (zero intake policy)

– Engineered Controls

– Procedural Controls

– Personnel Protective Equipment (PPE)

– Surveillance

SRDB# 167851
Surveillance

 Used to verify effectiveness of engineered controls, procedural controls 

and Personal Protective Equipment (PPE)

– Air Monitoring

– Facility Contamination Surveys

– Personnel Contamination Surveys

– Routine Bioassay

SRDB# 167851
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

SRDB# 167757
Actual 

Subcontractor 

Monitoring 

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 SRDB# 167757
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

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

SRDB# 167851
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 and required 

follow-up

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 

(1 of 5)

 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 

used for surveillance to confirm adequacy of workplace monitoring 

and controls. 

– Routine or prescheduled bioassay monitoring was the primary method 

of 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 

(2 of 5)

 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.“ (SRDB 167497)
Implications for Dose Reconstruction under EEOICPA 

(3 of 5)

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

there is no missing bioassay in 1997 regardless of the initial 66% 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. 

 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 

(4 of 5)

 SC&A has not demonstrated that subcontractors were primarily or only 

monitored via job-specific bioassay that would bias a co-worker model. 

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

operations workers (WSRC)

 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 as we will demonstrate in our next 

presentation on subcontractor monitoring data in NOCTS.
Implications for Dose Reconstruction under EEOICPA 

(5 of 5)

 There are NO evidence of a workplace exposure nor an indication that 

there was a missed intake of radionuclides at the Savannah River Site.

 Significant workplace and individual monitoring information through the 

surveillance including over 10,000 bioassay samples in 1997 to support 

that there was no internal dose that went undetected.

 NIOSH therefore concludes that dose reconstruction is feasible and 

sufficiently accurate through the use of a co-worker model.