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NIOSH Response to SC&A Comments on 

ORAUT-RPRT-0072

Response Paper 

National Institute for Occupational Safety and Health 

January 4, 2019 

Mike Mahathy 

Oak Ridge Associated Universities Team

Reviewed by Timothy Taulbee

Division of Compensation Analysis and Support 

This is a working document prepared by NIOSH’s Division of Compensation Analysis and Support (DCAS) or its contractor for use in discussions 

with the ABRWH or its Working Groups or Subcommittees. Draft, preliminary, interim, and White Paper documents are not final NIOSH or 

ABRWH (or their technical support and review contractors) positions unless specifically marked as such. This document represents preliminary 

positions taken on technical issues prepared by NIOSH or its contractor. NOTICE: This report has been reviewed to identify and redact any 

information that is protected by the Privacy Act 5 USC §552a and has been cleared for distribution. 
Response Paper NIOSH Response to SC&A Comments on 

ORAUT-RPRT-0072

January 4, 2019

Page 2 of 6

This is a working document prepared by NIOSH’s Division of Compensation Analysis and Support (DCAS) or its contractor for use in discussions 

with the ABRWH or its Working Groups or Subcommittees. Draft, preliminary, interim, and White Paper documents are not final NIOSH or 

ABRWH (or their technical support and review contractors) positions unless specifically marked as such. This document represents preliminary 

positions taken on technical issues prepared by NIOSH or its contractor. NOTICE: This report has been reviewed to identify and redact any 

information that is protected by the Privacy Act 5 USC §552a and has been cleared for distribution. 

INTRODUCTION

In 2017, the ORAU Team issued ORAUT-RPRT-0072, Locations of Stable Metal Tritide Use at 

the Savannah River Site (ORAUT 2017a). This is an assessment of special metal tritides and 

internal dosimetric considerations at Savannah River Site (SRS) from 1972 through 1989. In 

response to ORAUT 2017, SC&A issued Memorandum: SC&A Comments on ORAUT-RPRT0072, Revision 00, “Locations of Stable Metal Tritide Use at the Savannah River Site” (SC&A 

2018). In this document, the ORAU Team responds to three specific questions raised by SC&A 

in their review of ORAUT-RPRT-0072. 

NIOSH RESPONSES TO SC&A COMMENTS

SC&A Specific Question 1: Section 2.0, Introduction, notes that the “primary objective of this 

document is to provide information on the potential sources of stable tritium compounds at SRS” 

(page 6). Assuming that stable tritium compounds are the same as special tritium compounds 

(STCs), from a terminology standpoint, it is not clear why organically bound tritium (OBTs) are 

not also addressed in some fashion in this report. As a key component of STCs, they are 

addressed in OTIB-0066 and were surveyed in detail by SRS along with SMTs in the early 1990s 

(e.g., in Howard 2000), with potential OBT exposure sources identified for mercury diffusion 

pumps and mechanical vacuum pumps, in particular. If only SMTs are being addressed in 

ORAUT-RPRT-0072, that should be clarified in this section, with some rationale provided for 

excluding OBTs.

NIOSH Response: Although NIOSH considered Howard 2000 in the development of ORAUTRPRT-0072, some materials were not included in the report’s discussion. NIOSH agrees that 

ORAUT-RPRT-0072 should have listed OBTs. Nonetheless, dosimetric considerations for 

OBTs are included in the report. Doses from OBT intakes at SRS will be derived using the 

guidance in ORAUT-OTIB-0066, Calculation of Dose from Intakes of Special Tritium 

Compounds (ORAUT 2007), and ORAUT-OTIB-0011, Tritium Calculated and Missed Dose 

Estimates (ORAUT 2004).
Response Paper NIOSH Response to SC&A Comments on 

ORAUT-RPRT-0072

January 4, 2019

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This is a working document prepared by NIOSH’s Division of Compensation Analysis and Support (DCAS) or its contractor for use in discussions 

with the ABRWH or its Working Groups or Subcommittees. Draft, preliminary, interim, and White Paper documents are not final NIOSH or 

ABRWH (or their technical support and review contractors) positions unless specifically marked as such. This document represents preliminary 

positions taken on technical issues prepared by NIOSH or its contractor. NOTICE: This report has been reviewed to identify and redact any 

information that is protected by the Privacy Act 5 USC §552a and has been cleared for distribution. 

SC&A Specific Question 2: It is not clear if ORAUT-RPRT-0072 addresses the historical use of 

lithium deutero-tritide (LiDT) at SRS. According to a 2000 survey conducted for STCs at the 

Savannah River Technology Center (Howard 2000, page 6): 

“The two bench scale development projects that were conducted in 773-A in the past had 

their tritium in the form of tritiated heavy water (DTO), lithium deutero-tritide (LiDT), 

uranium tritide, and tritiated mercury. The quantities of these materials ranged from tens of 

grams up to a few kilograms.” 

SC&A did not find lithium deutero-tritide listed in ORAUT-RPRT-0072, although lithium tritide 

is identified (are they the same SMTs?). If lithium deuteron-tritide is a distinct compound from 

the others, it should be addressed as such. 

NIOSH Response: There is no difference in the kinetics of LiH versus Lid versus LiT that 

would result in different dissolution rates among the compounds in the lung (ORAUT, 2018). 

As such, LiDT should be treated the same as LiT.

SC&A Specific Question 3: In terms of potential operational sources of STCs, no discussion is 

provided for contamination during D&D activities, which were extensive during the 1990s 

(including the closure of the older tritium facilities). Given the engineering controls in place, the 

D&D phase would have been an operational phase with some vulnerability for SMT exposure. 

NIOSH Response: Co-worker intakes from tritium published in ORAUT-RPRT-0081, Section 

4.2, cover all activities and are stratified between operations and trade workers, the latter being 

involved in D&D tasks (ORAUT 2017b). Construction trade workers (CTW) included both 

prime contractor and subcontractor workers. 

Figure 1 shows a box plot of tritium dose statistics for prime versus subcontractor CTW. Median 

doses for subcontractor CTW are lower than the median dose for prime CTW in all years. The 

95th percentile dose for prime CTW is higher than that of subcontractor CTW for all but three 

years.
Response Paper NIOSH Response to SC&A Comments on 

ORAUT-RPRT-0072

January 4, 2019

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This is a working document prepared by NIOSH’s Division of Compensation Analysis and Support (DCAS) or its contractor for use in discussions 

with the ABRWH or its Working Groups or Subcommittees. Draft, preliminary, interim, and White Paper documents are not final NIOSH or 

ABRWH (or their technical support and review contractors) positions unless specifically marked as such. This document represents preliminary 

positions taken on technical issues prepared by NIOSH or its contractor. NOTICE: This report has been reviewed to identify and redact any 

information that is protected by the Privacy Act 5 USC §552a and has been cleared for distribution. 

Figure 1. SRS Tritium Annual Doses
Response Paper NIOSH Response to SC&A Comments on 

ORAUT-RPRT-0072

January 4, 2019

Page 5 of 6

This is a working document prepared by NIOSH’s Division of Compensation Analysis and Support (DCAS) or its contractor for use in discussions 

with the ABRWH or its Working Groups or Subcommittees. Draft, preliminary, interim, and White Paper documents are not final NIOSH or 

ABRWH (or their technical support and review contractors) positions unless specifically marked as such. This document represents preliminary 

positions taken on technical issues prepared by NIOSH or its contractor. NOTICE: This report has been reviewed to identify and redact any 

information that is protected by the Privacy Act 5 USC §552a and has been cleared for distribution. 

Figure 2 shows derived 95th percentile doses plotted by year for prime CTW, subcontractor 

CTW, and non-CTW. The line for the 95th percentile dose for subcontractor CTW is always less 

than that for non-CTW, and generally for prime CTW.

Figure 2. SRS Tritium Doses, 95th Percentiles

NIOSH concludes that derived co-worker intakes for tritium are sufficiently accurate to bound 

doses from work in D&D operations for missed and unmonitored doses. 
Response Paper NIOSH Response to SC&A Comments on 

ORAUT-RPRT-0072

January 4, 2019

Page 6 of 6

This is a working document prepared by NIOSH’s Division of Compensation Analysis and Support (DCAS) or its contractor for use in discussions 

with the ABRWH or its Working Groups or Subcommittees. Draft, preliminary, interim, and White Paper documents are not final NIOSH or 

ABRWH (or their technical support and review contractors) positions unless specifically marked as such. This document represents preliminary 

positions taken on technical issues prepared by NIOSH or its contractor. NOTICE: This report has been reviewed to identify and redact any 

information that is protected by the Privacy Act 5 USC §552a and has been cleared for distribution.

REFERENCES

Howard 2000, Special Tritium Compounds in the Savannah River Technology Center, internal 

memorandum from D. W. Howard to N. D. Johnson, Westinghouse Savannah River Company, 

Savannah River Site, Aiken, S.C., August 2. [SRDB Ref. ID 94505]

ORAUT (Oak Ridge Associated Universities Team) 2004, Tritium Calculated and Missed Dose 

Estimates, ORAUT-OTIB-0011, Rev 00, June 29. [SRDB Ref ID: 19430]

ORAUT (Oak Ridge Associated Universities Team) 2007, Calculation of Dose from Intakes of 

Special Tritium Compounds, ORAUT-OTIB-0066, Rev 00, April 26. [SRDB Ref ID: 31421

ORAUT (Oak Ridge Associated Universities Team) 2017a, Locations of Stable Metal Tritide 

Use at the Savannah River Site, ORAUT-RPRT-0072, Rev 00, January 9. [SRDB Ref ID: 

165215]

ORAUT (Oak Ridge Associated Universities Team) 2017b, Appropriateness of Using 1997 

Gross Alpha Air Sampling Data as a Method of Bounding Thoron Intakes at the SRS H-Area 

Tank Farm Between 1972 and 1994, ORAUT-RPRT-0081, Rev 00, April 7. [SRDB Ref ID: 

166258]

ORAUT (Oak Ridge Associated Universities Team) 2018, internal ORAU Team email 

correspondence regarding contact with SRS staff regarding the kinetics of LiH, LiD, and LiT, 

December 18. [SRDB Ref ID: 175269]

SC&A (SC&A, Inc.) 2018, Memorandum: SC&A Comments on ORAUT-RPRT-0072, Revision 

00, “Locations of Stable Metal Tritide Use at the Savannah River Site”, August 3. [SRDB Ref 

ID: 175266]