DISCLAIMER: This is a working document provided by the Centers for Disease Control and Prevention (CDC) 

technical support contractor, SC&A for use in discussions with the National Institute for Occupational Safety and 

Health (NIOSH) and the Advisory Board on Radiation and Worker Health (ABRWH), including its Working Groups or 

Subcommittees. Documents produced by SC&A, such as memorandum, white paper, draft or working documents are 

not final NIOSH or ABRWH products or positions, unless specifically marked as such. This document prepared by 

SC&A represents its preliminary evaluation on technical issues.

NOTICE: This document has been reviewed to identify and redact any information that is protected by the 

Privacy Act 5 U.S.C. § 552a and has been cleared for distribution. 

Memorandum

To: Subcommittee for Procedure Reviews

From: SC&A, Inc.

Date: April 28, 2021

Subject: Focused Review of ORAUT-OTIB-0066, Revision 01, for Resolution of Issues

Introduction

At the February 18, 2021, meeting of the Subcommittee for Procedure Reviews (SCPR), the 

Advisory Board on Radiation and Worker Health tasked SC&A to perform a focused review of 

ORAUT-OTIB-0066, revision 01, “Calculation of Dose from Intakes of Special Tritium 

Compounds” (NIOSH, 2020; hereafter “OTIB-0066”), dated October 15, 2020. The purpose of 

this focused review was to determine if the National Institute for Occupational Safety and Health 

(NIOSH) addressed and resolved the issues raised in SC&A’s (2008) review of revision 00 of 

ORAUT-OTIB-0066 (NIOSH, 2007). 

The following documents are central to this review:

• ORAUT-OTIB-0066, revision 00, April 26, 2007 (NIOSH, 2007) 

• SCA-TR-TASK3-0010, revision 00, “Review of ORAUT-OTIB-0066, Calculation of 

Dose from Intakes of Special Tritium Compounds,” November 25, 2008 (SC&A, 2008) 

• ORAUT-OTIB-0066, revision 01 (NIOSH, 2020) 

This memorandum reports on the results of SC&A’s focused review of OTIB-0066, revision 01 

(NIOSH, 2020). 

Background

Section 2.0 of OTIB-0066 (NIOSH, 2020, p. 5) summarizes the issue that it is intended to 

address: 

Stable metal tritides (SMTs) are a class of tritium compounds that cannot be 

detected by urine bioassay as easily as tritium oxide. “Stable” is used to indicate 

that the tritium is not easily separated from the metal matrix in which it is bound. 

The material is more strongly retained in the lung, resulting in much smaller 

fractions of the intake excreted in urine. Therefore, a relatively small amount of 

tritium in a urine sample can indicate a large intake of an SMT. Ideally, 

workplace information, in the form of air monitoring, surface contamination 
SC&A, Inc.

Focused Review of OTIB-0066, page 2 April 28, 2021

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Privacy Act 5 U.S.C. § 552a and has been cleared for distribution. 

activity, and process knowledge, are used to assign potential intakes of this 

material, which is addressed in a site profile when possible.

In the absence of other available monitoring data, urinalysis can be used to 

provide a best estimate of an intake. The purpose of this TIB is to provide 

guidance on how to use urine bioassay data to calculate best estimates of the 

annual organ doses for intakes of tritium in a metal matrix. 

Evaluation of Resolution of Findings 

SC&A’s (2008) evaluation of revision 00 of OTIB-0066 had four findings. After discussions 

among the participants and per SC&A’s recommendations at the March 24, 2009, SCPR

meeting, the Subcommittee placed findings 1 and 3 in abeyance and closed findings 2 and 4. The 

status each finding is currently reflected in their Board Review System (BRS) entries. This

review discusses the two findings that are in abeyance. 

Finding 1 (listed as issue 3 in SC&A, 2008): 

The recommendation given in ORAUT-OTIB-0066 to assess dose due to intake 

of OBT [organically bound tritium] is not claimant favorable. The OTIB 

recommends the use of the methodology given in ORAUT-OTIB-0011 [NIOSH, 

2004] to calculate doses from intakes of OBT to all organs and tissues. The dose 

coefficient for OBT given in ICRP Publication 78 (ICRP 1997), which is 

1.52 × 10-7 mrem/pCi (see Table 3); the one derived applying the biokinetic 

model for OBT (ICRP, 1989; ICRP, 1993; ICRP, 1995; and ICRP, 1997) using 

the AIDE computer code, which is 1.52 × 10-7 mrem/pCi (see Table 3); and the 

one derived using the methodology given in ORAUT-OTIB-0066 ([NIOSH, 

2007]), which is also 1.52 × 10-7 mrem/pCi (see Table 2), are 1.4 times higher 

than the one obtained applying the methodology given in ORAUT-OTIB-0011 

([NIOSH, 2004]), which is 1.08 × 10-7 mrem/pCi. [SC&A, 2008, p. 16] 

NIOSH responded in its BRS entry of January 23, 2009: 

The reviewer is correct. The factor of 1.4 is correct for a Type 1 calculation on the 

urinary excretion during a chronic intake, but the adjustment is somewhat larger 

for Type 2 and Type 3 calculations. The algorithm used in ORAUT-OTIB-0011 

can be modified to provide a claimant favorable dose from intakes of pure 

organically bound tritium (OBT), i.e., it is not necessary to use IMBA [Integrated 

Modules for Bioassay Analysis] in this case. ORAUT-OTIB-0011 will be revised 

to incorporate these changes. 

The most recent NIOSH BRS entry, dated October 21, 2020, states: 

The recommendation to use the methodology given in ORAUT-OTIB-0011 to 

calculate doses from intakes of OBT to all organs and tissues has been removed in 

Rev. 01 of this document. It now specifies that IMBA must be used for such an 

assessment. 
SC&A, Inc.

Focused Review of OTIB-0066, page 3 April 28, 2021

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SC&A compared the two versions of OTIB-0066 to identify changes relevant to finding 1 and 

noted that NIOSH modified recommendation 2 (Section 5.0) and added a new Recommendation 

3, increasing the number of recommendations from five to six. The relevant recommendations in 

revision 01 of OTIB-0066 now read as follows: 

• Recommendation 2: “The method in ORAUT-OTIB-0011 . . . can be used without 

modification to calculate doses from intakes of HTO [tritiated water] to all organs and 

tissues” (NIOSH, 2020, p. 10). Revision 00 included “and OBT” after “HTO.”

• Recommendation 3: “Because the ORAUT-OTIB-0011 . . . method underestimates the 

dose from an OBT intake by about 30%, it cannot be used for assessment of OBT. IMBA 

must be used for intake assessments when based on urine bioassay and IMBA or Web 

CAD used for dose assessment” (NIOSH, 2020, p. 10). 

SC&A believes that revision 01 of OTIB-066 adequately addresses the concerns of finding 1 and 

recommends that its status be changed to closed. 

Finding 3 (listed as issue 5 in SC&A, 2008): 

OTIB-0066 does not ensure that resultant doses are based on adequate monitoring 

data. . . . 

The method of choice for personnel monitoring is particulate air monitoring; 

however, there are multiple issues with the use of these data. [SC&A, 2008, p. 18] 

NIOSH responded in its BRS entry of January 23, 2009: 

NIOSH agrees that air monitoring data are useful for evaluating intakes of stable 

metal tritides (SMT) (and most other radioactive materials). However, in the 

absence of such data, urine bioassay can be used to bound the SMT intake and 

subsequent dose to the respiratory tract and systemic organs. 

A discussion of the practical interpretation of urinalysis results following an 

intake of SMT and the technical shortfalls associated with using urine bioassay 

data might be useful to the dose reconstructors and therefore will be added to 

ORAUT-OTIB-0066. 

The most recent NIOSH BRS entry, dated October 21, 2020, states, “A paragraph was added to 

the Purpose section of Rev. 01 of this document that discusses the limitations associated with the 

use of urine sampling for quantifying SMT intakes.” 

Section 2.0, “Purpose,” of OTIB-0066, revision 01, which is quoted in full in the “Background” 

section of this memorandum, is a substantial expansion of the original section in revision 00, 

which only stated: 

The purpose of this TIB is to provide guidance on how to use urine bioassay data 

to calculate the best estimates of the annual organ doses for intakes of tritium 
SC&A, Inc.

Focused Review of OTIB-0066, page 4 April 28, 2021

NOTICE: This document has been reviewed to identify and redact any information that is protected by the 

Privacy Act 5 U.S.C. § 552a and has been cleared for distribution. 

bound to organic compounds (organically bout tritium; OBT) and tritium in a 

metal matrix (stable metal tritide; SMT). [NIOSH, 2007, p. 5] 

SC&A believes that revision 01 of OTIB-0066 adequately addresses the concerns of finding 3 

and recommends that its status be changed to closed. 

Summary and Conclusions

SC&A performed a focused review of ORAUT-OTIB-0066, revision 01 (NIOSH, 2020), to 

determine if the current revision addresses and resolves the two “in abeyance” findings (1 and 3) 

from SC&A’s (2008) review of revision 00 (NIOSH, 2007). SC&A concludes that both findings 

have been adequately addressed and resolved and recommends closure.

References

International Commission on Radiological Protection (ICRP). (1989). Age-dependent doses to 

members of the public from intake of radionuclides: Part 1 (Publication 56). Ann. ICRP, 20(2).

International Commission on Radiological Protection. (1993). Age-dependent doses to members 

of the public from intake of radionuclides: Part 2 ingestion dose coefficients (Publication 67). 

Ann. ICRP, 23(3-4). SRDB Ref. ID 176884 

International Commission on Radiological Protection. (1995). Age-dependent doses to members 

of the public from intake of radionuclides: Part 4 inhalation dose coefficients (Publication 71).

Ann ICRP, 25(3-4). SRDB Ref. ID 22729 

International Commission on Radiological Protection. (1997). Individual monitoring for internal 

exposure of workers (Publication 78). Ann. ICRP, 27(3-4). 

National Institute for Occupational Safety and Health. (2004). Technical information bulletin: 

Tritium calculated and missed dose estimates (ORAUT-OTIB-0011, rev. 00). SRDB Ref. 

ID 19430 

National Institute for Occupational Safety and Health. (2007). Calculation of dose from intakes 

of special tritium compounds (ORAUT-OTIB-0066, rev. 00). SRDB Ref. ID 31421 

National Institute for Occupational Safety and Health. (2020). Calculation of dose from intakes 

of special tritium compounds (ORAUT-OTIB-0066, rev. 01). SRDB Ref. ID 183483 

SC&A, Inc. (2008). Review of ORAUT-OTIB-0066, Calculation of dose from intakes of special 

tritium compounds (SCA-TR-TASK3-0010, rev. 0). 

https://www.cdc.gov/niosh/ocas/pdfs/abrwh/scarpts/sca-tib66-r0.pdf