Draft

ADVISORY BOARD ON 

RADIATION AND WORKER HEALTH 

National Institute for Occupational Safety and Health 

SC&A RESPONSE TO REVISION 3 OF NIOSH’S “FOLLOW-UP 

EFFORTS ON SEC-00192, ROCKY FLATS PLANT TRITIUM 

ISSUES, WHITE PAPER,” DECEMBER 28, 2015

Contract No. 211-2014-58081 

SCA-TR-2016-SEC005, Revision 0 

Prepared by 

John Mauro, PhD, CHP

Joyce L. Lipsztein, PhD

Doug Farver, CHP 

Nicole Briggs

SC&A, Inc.

1608 Spring Hill Road, Suite 400 

Vienna, Virginia 22182 

Saliant, Inc.

5579 Catholic Church Road 

Jefferson, Maryland 21755 

June 2016 

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 report 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.
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SC&A, INC.: Technical Support for the Advisory Board on Radiation & 

Worker Health Review of NIOSH Dose Reconstruction Program

DOCUMENT TITLE: 

SC&A Response to Revision 3 of NIOSH’s “Follow-up Efforts on 

SEC-00192, Rocky Flats Plant Tritium Issues, White Paper,” 

December 28, 2015

DOCUMENT NUMBER/

DESCRIPTION:

SCA-TR-2016-SEC005

REVISION NO.: 0 (Draft)

SUPERSEDES: N/A

EFFECTIVE DATE: June 6, 2016

TASK MANAGER: Joseph Fitzgerald [signature on file]

PROJECT MANAGER: John Stiver, MS, CHP [signature on file]

DOCUMENT 

REVIEWER(S):

Joseph Fitzgerald

John Stiver

Record of Revisions

Revision 

Number

Effective 

Date Description of Revision

0 (Draft) 06/06/2016 Initial issue
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TABLE OF CONTENTS

Abbreviations and Acronyms ..........................................................................................................5

1.0 Introduction ..........................................................................................................................6

2.0 Comments on Revision of PART II of Appendix 1: Rocky Flats Tritium Dose 

Assignment for 1973 and the Tritiated Water Model as Shown in Attachment A ..............7

2.1 Summary of NIOSH Assumptions...........................................................................7

2.2 SC&A Review of NIOSH Assumptions ..................................................................8

3.0 Review of Issues Related to the Reconstruction of Exposures to Tritium at Rocky 

Flats Post-1973...................................................................................................................10

3.1 SC&A Issue 1 ........................................................................................................10

3.1.1 Material Provided by NIOSH that Addresses this Issue and SC&A’s 

Position on this Issue .................................................................................10

3.2 SC&A Issue 2 ........................................................................................................13

3.2.1 Material Provided by NIOSH that Addresses this Issue and SC&A’s 

Position on this Issue .................................................................................14

3.3 SC&A Issue 3 ........................................................................................................15

3.3.1 Material Provided by NIOSH that Addresses this Issue and SC&A’s 

Position on this Issue .................................................................................15

3.4 SC&A Issue 4 ........................................................................................................15

3.4.1 Material Provided by NIOSH that Addresses this Issue and SC&A’s 

Position on this Issue .................................................................................16

3.5 SC&A Issue 5 ........................................................................................................16

3.5.1 Material Provided by NIOSH that Addresses this Issue and SC&A’s 

Position on this Issue .................................................................................16

3.6 SC&A Issue 6 ........................................................................................................17

3.6.1 Material Provided by NIOSH that Addresses this Issue and SC&A’s 

Position on this Issue .................................................................................17

3.7 SC&A Issue 7 ........................................................................................................17

3.7.1 Material Provided by NIOSH that Addresses this Issue and SC&A’s 

Position on this Issue .................................................................................17

3.8 SC&A Issue 8 ........................................................................................................17

3.8.1 Material Provided by NIOSH that Addresses this Issue and SC&A’s 

Position on this Issue .................................................................................17

3.9 SC&A Issue 9 ........................................................................................................17

3.9.1 Material Provided by NIOSH that Addresses this Issue and SC&A’s 

Position on this Issue .................................................................................18

4.0 Revision of PART III of Appendix 1: Example RFP Tritium Dose Reconstruction.........18

5.0 Overall Conclusions ...........................................................................................................19
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6.0 References ..........................................................................................................................19

Appendix A: Compendium of Airborne Concentration of Tritium at Rocky Flats Based on 

Tritium Bubbler Samples ...................................................................................................22
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ABBREVIATIONS AND ACRONYMS

ABRWH

or Advisory Board Advisory Board on Radiation and Worker Health

AEC Atomic Energy Commission

Ci curie

ER evaluation report 

H hydrogen 

H-3 tritium

HTO tritiated water or tritium oxide 

ICRP International Commission on Radiation Protection

IMBA Integrated Modules for Bioassay Analysis

IREP Interactive RadioEpidemiological Program 

μCi microcurie

μCi/m3 microcurie per cubic meter

MDA minimum detectable activity

mrem millirem

mrem/d millirem per day

mrem/yr millirem per year

NCRP National Council on Radiation Protection and Measurements 

NIOSH National Institute for Occupational Safety and Health

NOCTS NIOSH OCAS Claims Tracking System

pCi/day picocurie per day 

pCi/L picocurie per liter

pCi/m3 picocurie per cubic meter 

RCG Radio Concentration Guidelines 

RFP Rocky Flats Plant

RFPAO Rocky Flats Area Office

SEC Special Exposure Cohort 

SRDB Site Research Database

yr year
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1.0 INTRODUCTION

An exchange of white papers and Work Group discussions of issues related to the reconstruction 

of exposures of workers to tritium (also referred to as “H-3”) at the Rocky Flats Plant (RFP) has 

been ongoing [see the timeline provided on page 34 of the National Institute for Occupational 

Safety and Health’s (NIOSH’s) December 28, 2015, white paper (NIOSH 2015a) cited and 

described below]. As part of these continuing investigations, in September 2014, SC&A issued 

SC&A Response to NIOSH White Paper: “Follow-up Efforts on SEC-00192 Rocky Flats Plant 

Tritium Issues,” dated May 30, 2014 (SC&A 2014). On December 28, 2015, partly in response 

to SC&A’s September 2014 white paper, NIOSH issued Follow-up Efforts on SEC-00192, Rocky 

Flats Plant Tritium Issues, White Paper, Revision 3 (NIOSH 2015a). These white papers are part 

of a series of investigations performed in support of the Special Exposure Cohort (SEC) Petition 

SEC-00192 Rocky Flats Plant Special Exposure Cohort Petition Evaluation Report presented to 

the Advisory Board on Radiation and Worker Health (“Advisory Board”) in September 2012 

(NIOSH 2013). 

The introduction of NIOSH’s December 28, 2015, white paper (hereafter referred to as “NIOSH 

2015a”) states the following as the basis for the new material compiled by NIOSH since the last 

Work Group meeting that updates, supplements, and/or confirms its position with respect to 

these matters:

As part of the initial follow-up, additional document data captures and personnel 

interviews were performed (classified and unclassified) to: (1) clarify the 

existence of tritium on site and associated personnel exposures; (2) expand the 

investigation on tritium bubbler sampling; (3) confirm the existence of shipping 

container tritium surveys; and (4) confirm the type and amount of sampling 

analysis performed in Building 123. These initial follow-up efforts were 

performed to validate the tritium bounding method for the SEC-00192 RFP ER 

(which uses information from the 1973 tritium incident as the maximum exposure 

scenario), and to provide more precise estimates of doses due to tritium.

In this latest revision, NIOSH provided additional document data captures regarding the 

existence of tritium on site and associated personnel exposures, as well as follow-up on tritium 

bubbler sampling, shipping container tritium surveys, and sampling analysis performed in 

Building 123. 

NIOSH 2015a presents NIOSH’s approach to dose reconstruction to tritium exposures in 

Appendix 1, as follows: 

• Part I, “Analysis of Rocky Flats Plant Tritium Exposures for 1959–1973,” by 

J. S. Bogard, Oak Ridge Associated Universities Team (ORAUT)

• Part II, “Rocky Flats Tritium Dose Assignment for 1973 and Later,” by E. M. Brackett, 

ORAUT; and Attachment A, “Tritiated Water Models,” by Thomas LaBone, Nancy 

Chalmers, and E. M. Brackett, ORAUT

• Part III, “Example RFP Tritium Dose Reconstruction,” by Mutty Sharfi, ORAUT
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In NIOSH 2015a, NIOSH repeats most of the information presented in Revision 2 of the paper. 

(NIOSH 2015b; July 1, 2015). At the Work Group meeting on July 14, 2015, it was agreed that 

the method used by NIOSH to assign pre-1973 chronic tritium exposures to all workers was 

acceptable to the Work Group, as a bounding approach, and that issue was closed. The most 

relevant changes presented in Revision 3 of the white paper (NIOSH 2015a) are the revised 

approaches for tritium dose assignment for 1973 and later, presented in Part II of Appendix 1 and 

its application in Part III.

As the method used by NIOSH to assign pre-1973 doses was accepted during the July 2015 

Work Group meeting, SC&A focused its reviews on NIOSH’s approach for tritium dose 

assignments at RFP for 1973 and later. 

SC&A has analyzed the RFP tritium dose assignment for 1973 in Part II of Appendix 1 of 

NIOSH 2015a, as well as Attachment A to Part II, where the model to calculate urinary excretion 

following an acute uptake of tritiated water (HTO) is described. SC&A has reviewed issues 

related to the reconstruction of exposures to tritium at RFP post-1973 (in Part II of Appendix 1). 

SC&A’s review addresses the expanded NIOSH review in NIOSH 2015a in terms of the nine 

original issues raised by SC&A in its September 2014 white paper for the post-1973 time period. 

In addition, SC&A has reviewed Part III of Appendix 1 to NIOSH 2015a, where the doses 

assigned for workers in the pre-1973, 1973, and post-1973 periods of exposure are used in an 

example for dose reconstruction. 

2.0 COMMENTS ON REVISION OF PART II OF APPENDIX 1: ROCKY

FLATS TRITIUM DOSE ASSIGNMENT FOR 1973 AND THE 

TRITIATED WATER MODEL AS SHOWN IN ATTACHMENT A 

2.1 SUMMARY OF NIOSH ASSUMPTIONS

In NIOSH 2015a, NIOSH describes a 1973 incident that prompted the site to sample a number of 

workers for tritium exposure. The incident occurred due to the processing of tritiumcontaminated material that was processed at the RFP from April 9 to April 25, 1973. Because it 

was not immediately identified as being contaminated, monitoring of potentially exposed 

individuals did not begin until late September 1973. Two-hundred-fifty people were sampled 

following the discovery; this included all employees who worked in areas in which the 

contaminated scrap was processed or who were involved in the processing of wastes from this 

scrap. The five most exposed individuals were identified [urine levels higher than 10,000 

picocuries per liter (pCi/L), the action level of the site]. 

Because the tritium contamination was associated with handling plutonium scrap material, 

NIOSH has taken the position that (1) tritium doses will be assigned to all individuals who were 

monitored for plutonium in 1973, (2) doses will be assessed on an individual basis using reported 

H-3 bioassay results and any additional information in the NIOSH OCAS Claims Tracking 

System (NOCTS) file, and (3) for those who were not monitored for H-3, dose will be assigned 

based on claimant-favorable assumptions. 
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The tritium release incident report [Site Research Database (SRDB) Ref. ID 24165] discusses the 

tritium sampling of 250 people as of October 15, 1973. There are no results or specific sample 

dates given in the report for those individuals who did not exceed the H-3 bioassay follow-up 

action level of 10,000 pCi/L. Only five individuals were found to have results exceeding the 

action level, so NIOSH’s assessment is based on the assumption that these individuals were the 

maximally exposed workers due to the incident, and that those workers who were not monitored 

would not have been exposed at those same levels. After discussions about the tritium model at 

the RFP work group meeting, NIOSH decided to adopt the use of the tritium model described in 

“Review of the ICRP Tritium and C-14 Internal Dosimetry Models and Their Implementation in 

the GENMOD-PC Code,” by R. B. Richardson and D. W. Dunford (2001), for this assessment. 

Based on this information, the following assumptions were applied: 

• H-3 was in the form of HTO. 

• The model for inorganic H-3 is as described in “Review of the ICRP Tritium and C-14 

Internal Dosimetry Models and Their Implementation in the GENMOD-PC Code,” by 

R. B. Richardson and D. W. Dunford (2001). 

• The mode of intake was injection [for modeling with Integrated Modules for Bioassay 

Analysis (IMBA)]. 

• The tritium date of intake was April 9, 1973 (first day the material was processed). 

• Urine samples were collected on October 15, 1973. 

• Sample result = 10,000 pCi/L (14,000 pCi/day urinary excretion rate), 187 days after the 

assumed intake date of April 9, 1973. 

Using this information, NIOSH estimated a total dose of 103 millirem (mrem) due to the April 

1973 incident 

2.2 SC&A REVIEW OF NIOSH ASSUMPTIONS 

SC&A reviewed the Richardson and Dunford (2001) model cited by NIOSH 2015a. The model 

is similar to the one used by the National Council on Radiation Protection and Measurements 

(NCRP) in its Report No. 161 (NCRP 2008; hereafter “NCRP 161”), but there are some 

differences. For example, though Richardson and Dunford (2001) suggested that the fraction 

excreted in urine is 0.47, the excretion fraction from body to urine in NCRP 161 is 0.55. This 

model is also similar to the International Commission on Radiation Protection (ICRP) retention 

and dosimetric model for tritiated water [ICRP Publication 78 (1997); hereafter “ICRP 78”], 

although neither the ICRP nor the NCRP models include the bladder compartment.

NIOSH modified the Richardson and Dunford (2001) model, introducing the bladder 

compartment. The ICRP and the NCRP did not consider the delay in excretion pathway due to 

the bladder. According to ICRP 78, urinary excretion should not result in a significant additional 

dose to the bladder wall, which is assumed to receive the same dose as other tissues. Richardson 

and Dunford (2001) state the following: “We can find no evidence that any tritiated or C-14 

compound model requires a urinary bladder compartment” (page 293). 
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In spite of the introduction of the urinary bladder, SC&A finds that the delay caused by 

introducing the urinary bladder will not cause a relevant difference in the interpretation of the 

urinary excretion of tritium in terms of intake and dose. 

The Richardson and Dunford model, published in 2001, was not experimentally tested for times 

as long as 187 days and thus, theoretically, should not be applied in this case. In addition, the 

same authors published a later paper (Richardson and Dunford 2003), that states: “The ICRP 

HTO model has limited use in a bioassay intake estimation, as it does not possess components 

that represent the long-term retention of tritium in the body that has been measured in bone, 

adipose tissue and other tissues and organs” (page 549). It proceeds to state that “there are no 

definite data available to evaluate tritium biokinetics, especially at long times after intake.” 

In previous discussions and white papers, SC&A suggested that NIOSH use a new draft ICRP 

(2012) model published on the ICRP website for public comment, which attempted to assign a 

long-term compartment to the tritium retention model. However, NIOSH indicated it could not 

use this model because it had not yet received formal ICRP endorsement. As an alternative, 

SC&A suggested the use of David Taylor’s model, which has three compartments, the third with 

a half-life compatible with the long-term retention in the body (Taylor 2003). This paper is cited 

in Richardson and Dunford’s 2003 paper, which, in many respects, is similar to the new draft 

ICRP model, suggested by SC&A. 

In summary, NIOSH’s proposed model assigns 103 mrem to unmonitored workers exposed or 

potentially exposed to tritium at RFP for 1973, based on a model that SC&A believes is 

appropriate for application to the long post-exposure time periods involved (i.e., 187 days). 

If the new ICRP model would have been used, as described in the consulting document posted 

for public comment on the ICRP website (ICRP 2012), or the model published by David Taylor 

(2003), the dose would be a little higher, i.e., 40 mrem to 50 mrem higher, depending on which 

dosimetric model is applied. As this dose is just assigned to one year, 1973, for non-monitored 

workers, SC&A finds that the difference in dose estimated will not be substantive and will have 

negligible influence on the Interactive RadioEpidemiological Program (IREP) probability of 

causation calculations. In addition, NIOSH used a conservative urinary excretion result, H-3 

bioassay follow-up action level of 10,000 pCi/L, instead of one-half the minimum detectable 

activity (MDA), and a maximum possible time interval between the intake and the sample 

collection date, which is claimant favorable. 

However, SC&A recommends the use of the intake date of April 9, 1973, both for the workers 

who had monitoring data higher than 10,000 pCi/L, and for the workers who had monitoring data 

less than 10,000 pCi/L, and who were all working in the location where the accident occurred at 

the time of its occurrence. The dose assigned to a person, based on urine excretion results, 

depends on the time lag between exposure and sample collection. The longer the time lag, the 

higher the dose assigned to the exposed worker. SC&A had previously agreed that urinary 

excretion rates of 10,000 pCi/L may be applied for workers who were not monitored. The 

assignment of the conservative intake date of April 9, 1973, should be the same for unmonitored 

and monitored workers, if they were present at the location of the incident. 
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3.0 REVIEW OF ISSUES RELATED TO THE RECONSTRUCTION OF 

EXPOSURES TO TRITIUM AT ROCKY FLATS POST-1973 

This section focuses on the nine issues raised by SC&A in its September 2014 white paper 

dealing with the reconstruction of exposures of Rocky Flats workers to tritium in 1974 and 1975 

(SC&A 2014); i.e., following the April 1973 incident. We have structured this section by first 

restating each of the nine issues raised by SC&A (2014) on this subject (in italics) and then 

exploring the degree to which NIOSH has satisfactorily addressed each of these issues in NIOSH 

2015a. 

3.1 SC&A ISSUE 1

Based on the review of the above SRDB folders, SC&A concurs that there do not 

appear to be any incidents post-1973 where the doses to workers could have been 

greater than the doses that might have been associated with the April 1973 

incident. In addition, there are considerable air sampling data, and a limited 

amount of bioassay data post-1973, that indicate that a plausible upper bound 

could be placed on the tritium exposures that workers might have experienced 

after the 1973 incident. However, one of our concerns is whether the locations of 

the bubblers are representative of the airborne tritium concentrations at the 

locations of the potentially exposed workers. Also, one of the conclusions on page 

20 of the May 30, 2014, white paper states that, “a co-worker study using data 

from NOCTS for 1974 and 1975 resulted in an annual dose of less than 1 mrem; 

therefore, no dose will be assigned for unmonitored tritium after 1973.” This 

conclusion is not consistent with the material provided in SRDB 8790, where the 

potential doses involved in the August 1974 incident were certainly higher than1 

mrem/yr, and it is unclear whether more than one of these incidents might have 

occurred. This observation also applies to the conclusion on page 22 of the 

NIOSH white paper that the bioassay data support a conclusion that the doses to 

workers from tritium for 1974 and 1975 were zero for everyone.1

 (SC&A 2014)

1 In preparing this report, we have determined that the doses associated with the August 1974 report were 

unlikely to have exceeded 1 mrem. Hence, this aspect of Issue 1 is retracted. 

3.1.1 Material Provided by NIOSH that Addresses this Issue and SC&A’s Position on this 

Issue

With respect to reconstructing tritium exposures in 1974 and 1975, NIOSH states the following 

on page 24 of NIOSH 2015a: 

Because tritium was not of primary concern at RFP and was present only as a 

potential contaminant on equipment, a given individual was not placed on a 

routine sampling program. Instead, a program was established whereby one-tenth 

of the urine samples collected for plutonium analysis were also analyzed for 

tritium content (SRDB 111267, letter from RFP General Manager to RFAO AEC 

Manager) as well as the collection of samples when a particular concern was 
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identified. Samples available in NOCTS for these two years indicate that analyses 

were performed throughout the year, with most individuals sampled only once. 

This section of NIOSH 2015a reiterates that the 1-in-10 bioassay program initiated in 1974 found 

no workers with tritium concentrations in urine that could be associated with an annual dose in 

excess of 1 millirem per year (mrem/yr). For this reason, NIOSH believes that no tritium dose 

should be assigned to any workers post-1973, except for workers who were explicitly monitored 

for a known acute release of tritium that occurred post-1973. 

Page 31 of NIOSH 2015a provides additional information pertinent to reconstructing post-1973 

exposures to tritium. The white paper explains that the 1-in-10 program involved bioassay 

samples from 38 individuals in 1974 and 37 individuals in 1975. Such a program would appear 

to provide compelling evidence that, other than known exposures to specific incidents, these data 

indicate that it is unlikely that workers at RFP experienced acute or chronic exposures to tritium 

post-1973 that could have resulted in exposures exceeding 1 mrem/yr. Such a conclusion must be 

viewed cautiously, because these persons were only bioassayed about once per year and, since 

tritium has an effective half-life in a body water of about 10 days, it is reasonable to ask whether 

a substantial acute intake of tritium could have been missed. 

With respect to this issue, it is possible that one or more undetected incidents occurred in 1974 

and 1975 and acute intakes occurred, but none were detected in the 75 urine samples collected 

over the 1974 and 1975 time period when the 1-in-10 program was in effect. As best as can be 

determined, the 75 urine samples were collected from workers who had the potential for 

exposure to plutonium, and that these include workers who opened containers that might have 

been contaminated with tritium. On this basis, it appears to be unlikely that one or more acute 

intakes occurred but were undetected by all 75 bioassay analyses. We would agree with this 

conclusion if the bioassay data were collected randomly among individuals involved in 

plutonium handling, including opening shipping containers and “pressure cookers,” and if the 

samples were collected in a manner that was more or less uniformly distributed in time over the 

course of the 1-in-10 tritium bioassay program. 

In order to ensure that NIOSH’s interpretation of the results of the 1-in-10 bioassay program is 

reasonable, SC&A posed two questions about the Rocky Flats tritium data sets, which we believe 

will help to confirm that NIOSH’s interpretation of the implication of the 1-in-10 program is 

reasonable. The two questions and associated discussions are as follows:

1. Were the 75 urine samples collected in 1974 and 1975 distributed randomly over the duration 

of the 1-in-10 program? 

This question goes to concerns that, if the samples were clustered in time—e.g., if they were all 

collected at the same time—the samples could have missed one or more acute intakes. In order to 

address this issue, we searched over 900 Rocky Flats tritium records in the SRDB to identify the 

dates when each urine sample was collected. In Section 5.3.5.3 of ORAUT-TKBS-0011-5, Rocky 

Flats Plant – Occupational Internal Dose, Revision 03 (ORAUT 2014), NIOSH states that an 

analysis of NOCTS data from 1974 and 1975 revealed that 38 employees in 1974 and 37 

employees in 1975 had tritium urinalysis testing as part of the 1-in-10 tritium testing protocol 

that was implemented following the April 1973 tritium release. This testing program appeared to 

have been in place from September 1974 (SRDB Ref. ID 111288) to September 1975 (SRDB 
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Ref. ID 24664). SC&A reviewed tritium bioassay-related documents for Rocky Flats on the 

SRDB, but the tritium bioassay data for 1974 and 1975 that were collected by NIOSH did not 

appear to be published in a single document. Even though the program managers did state that 

the testing was random, we could not confirm if the testing was distributed randomly during the 

1-in-10 program. SC&A did not perform a search of NOCTS to find the employees who were 

tested during this program because of the magnitude of the effort.

As a fallback position, we tried to obtain information about the frequency that urine samples 

were collected for plutonium analyses. For example, if urine samples were collected monthly for 

plutonium analysis, and the 1-in-10 urine bioassay samples came from these samples, we can 

have some level of assurance that the urine samples collected and analyzed for tritium as part of 

the 1-in-10 program were, in fact, distributed more or less randomly over 1974 and 1975. If this 

is the case, we can have increased confidence that the 1-in-10 program did not miss an acute 

exposure. Unfortunately, again, we were unable to obtain information of the frequency of the 

routine plutonium bioassay program. 

Observation 1: NIOSH should provide the results of each of the 75 bioassay measurements, 

including the dates the samples were collected and the results of the analyses.

2. Are there tritium emissions data that can be used to corroborate that no substantial releases of 

tritium occurred that might have been missed?

In order to help confirm that unusually high releases of tritium did not occur after 1973, we 

reviewed the Annual Environmental Monitoring Reports for a number of years and compared the 

reported releases to the atmosphere for a number of years (SRDB Ref. ID 8790) and also found a 

slide presentation (SRDB Ref. ID 110899) that fills in some gaps in the reported effluents, as 

shown in Tables 1 and 2. 

Table 1. SRDB Documents that Provide Tritium Releases to the Atmosphere

Year SRDB No. 8790

Reference ID

Tritium Release to 

the Atmosphere (Ci)

1974 966 10.38

1975 975 <1.5 Ci

1976 976 <1.159

1977 979 <0.528

1978 983 <0.941

1980 985 <0.842
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Table 2. Additional Information Regarding Tritium Releases to the Atmosphere

Year

Tritium Release to Atmosphere (Ci) 

(from page 9 of SRDB 110899)

1973 500 to 2000

1974 —

1975 <1.539

1976 <1.159

1977 <0.528

1978 <0.941

1979 <0.844

1980 <0.842

1981 <0.447

1982 <0.232

1983 <0.165

1984 0.148

1985 <0.155

1986 (through October) <0.197

The implications of these reported tritium releases are that the tritium release that occurred in 

August 1974—which was, in part, responsible for the relatively high atmospheric release that 

occurred in that year—does not appear to have been repeated in later years, where the tritium 

releases were quite small.

On the basis of the results of the 1-in-10 bioassay sampling program and the emissions 

monitoring program, it appears that it is unlikely that unmonitored workers in 1974 and 

subsequent years experienced tritium exposures in excess of 1 mrem/yr.

Further evidence that it is unlikely that one or more undetected large acute tritium intakes 

occurred in 1974 and 1975 and subsequent years, which could have resulted in exposures in 

excess of 1 mrem/yr, is provided by the result of the bubbler sampler data collected from 1974 

through 1991. This subject is addressed in SC&A Issues 2 and 3, which follow. 

3.2 SC&A ISSUE 2

In a related matter, Table A-2 of the NIOSH May 30, 2014, report and its 

supporting SRDB 8790 document, provide detailed air sampling data for 

Room 452 related to the August 1974 release. Our question is, were there other 

rooms where containers were opened, and if so, are there any air sampling data, 

swipe data, or effluent data that demonstrate that tritium releases did not occur at 

those locations? It appears that Item 2, under the section titled “Comment 

Reponses” beginning on page 36 of the NIOSH May 30, 2014, white paper 

provides information pertaining to this issue, but it is not clear that there is a high 

level of confidence that exposures to tritium associated with opening containers 

can be characterized and bounded. (SC&A 2014)
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3.2.1 Material Provided by NIOSH that Addresses this Issue and SC&A’s Position on this 

Issue

Material addressing bubbler data in NIOSH 2015a begins on page 4, with a summary of the 

bubbler program provided in Table 1 of that report. The NIOSH white paper presents a 

description of the bubbler sampling system from 1974 through 1991. Table A1-2 of the white 

paper provides airborne tritium concentrations for 1974. In addition, Appendix 3 (page 42) 

addresses airborne tritium monitoring from 1977 through 1981. Appendix 3 provides useful 

information on the number and location of bubblers, explaining that the bubblers were located 

where elevated levels of tritium might be expected. However, the white paper does not provide 

tritium concentrations in the air for later years [except to note that the highest airborne tritium 

concentration was 7,920 picocuries per cubic meter (pCi/m3)]. The paper would benefit by 

presenting information on the location and concentration of tritium as a function of time and 

whether the estimated airborne tritium concentrations take into consideration the efficiency of 

the bubblers. Such information would help to reassure us that there were no large undetected 

releases of tritium post-1974 that could have resulted in undetected exposures to workers in 

excess of 1 mrem per year.

NIOSH 2015a describes the data, reports, and interviews that were performed in order to 

determine if there were any substantial releases of tritium following the April 1973 incident and 

concludes that, collectively, there does not appear to be any evidence that there were tritium 

releases post-1973 that were comparable to the release that occurred in April 1973. However, the 

white paper does not review the data from the perspective that there might have been a multitude 

of relatively small tritium releases that could have resulted in post-1973 exposures in excess of 1 

mrem per year (other than the data collected for the August 1974 incident). 

In order to help validate NIOSH’s conclusion regarding post-1973 exposures, SC&A reviewed 

the bubbler data provided in the SRBD as a function of time and location in order to determine if 

any of the bubbler data revealed the presence of any unusual spikes in the airborne 

concentrations of tritium at any of the bubbler locations. We believe that this type of data can 

help to supplement the data obtained from the 1-in-10 bioassay program and the tritium 

atmospheric release data provided above. 

Appendix A presents a series of tables and excerpts that were compiled by SC&A from the 

SRDB in an attempt to determine if there were any unusually high concentrations of tritium at 

the bubbler locations from 1974 through 1981. As may be noted in Appendix A, the 1974 data 

collected from bubblers located in Room 457 of Building 777 reveal airborne tritium 

concentrations at the locations of the bubblers of about 1,000 to 5,000 pCi/m3

. As a point of 

reference, continuous exposure to 1 pCi/L of tritiated water is associated with an annual effective 

dose of 0.16 mrem/yr. Hence, continuous exposure to about 5,000 pCi/m3 of tritiated water is 

associated with an effective dose of about 1 mrem/yr, assuming the reported airborne tritium 

concentrations take bubbler efficiency into consideration. If one considers that many of the 

bubblers were located near downdraft tables or in exhaust plenums, the reported concentrations 

may overestimate the tritium concentrations at the breathing zone of workers. Hence, it is not 

unreasonable to conclude that undetected exposures in excess of 1 mrem/yr were unlikely, based 

on the bubbler data. 
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Observation 2. NIOSH should discuss whether the airborne tritium concentrations 

reported in the white paper take bubbler efficiency into consideration.

The bubbler data in Appendix A also reveal a large spike in the airborne tritium concentration of 

tritium of over 37 million pCi/m3 on August 30, 1974. The tritium concentration remained high 

for about 1 week, at which time the tritium concentrations appear to have returned to relatively 

normal levels for that time period (i.e., about 5,000 pCi/m3

). NIOSH 2015a indicates that followup bioassay data collected in response to this incident revealed doses of no greater than 0.15 

mrem. This dose would appear to be low if it is assumed that a person experienced the observed 

high airborne tritium concentrations for one or more days. However, the results of the bioassay 

program indicate that the actual exposures were less than 1 mrem. We accept this result because 

bioassay results are a much more accurate method for estimating radionuclide intake than air 

sampling data. The implication is that the high concentrations of airborne tritium observed at the 

bubbler locations were unlikely to be the concentrations experienced by workers, at least not for 

prolonged periods of time. 

Finally, the other bubbler data summarized in Appendix A for 1977 to 1981 reveal that the 

tritium concentrations did not likely exceed a level that could have been associated with 

exposures exceeding 1 mrem/yr. 

The implications of SC&A’s investigation described above for Issues 1 and 2 provide a weight 

of evidence that supports NIOSH’s conclusion that no workers experienced undetected 

exposures to tritium following the April 1973 incident that could have resulted in doses in excess 

of 1 mrem/yr. However, we encourage NIOSH to address the observations noted in this report. 

3.3 SC&A ISSUE 3

The NIOSH conclusion regarding doses post-1973 being less than 1 mrem/yr is 

likely based on the 1/10 bioassay program, but it is not apparent that the workers 

included in the bioassay program were bioassayed at a frequency that would have 

detected an incident. In addition, there are questions regarding the locations of 

the bubblers with respect to the degree to which those data are representative of 

the airborne tritium concentrations where workers might have been exposed to 

tritium. There are a substantial number of smear samples, but it is not apparent 

that the results of smear samples could be used to validate the conclusions that 

exposures to workers post-1973 were less than 1 mrem/yr. (SC&A 2014)

3.3.1 Material Provided by NIOSH that Addresses this Issue and SC&A’s Position on this 

Issue

This issue is discussed extensively as part of Issues 1 and 2 and need not be discussed here. 

3.4 SC&A ISSUE 4

Another concern we have regarding the post-1973 air sampling data is we did not 

find any reports that used two bubblers in series to confirm the efficiency of the 

bubbler for collecting tritium. We note that the efficiency of bubblers can be 

affected by humidity, the flow rate of air through the bubbler, and how long the 
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bubbler is on line before analysis. Some discussion of bubbler efficiency is 

required. (SC&A 2014)

3.4.1 Material Provided by NIOSH that Addresses this Issue and SC&A’s Position on this 

Issue

None of the NIOSH white papers address the efficiency of the bubblers. However, during the 

review of SRDB documents, SC&A found an efficiency concern identified in “Project Task 5 - 

Report - Estimating Historical Emissions from Rocky Flats 1952 – 1989” (ChemRisk 1994; 

SRDB Ref. ID 8017). According to that report, RFP has used an in-house-designed tritium 

sampler since 1973 for measurement of HTO in the exhaust ventilation. In 1978, a pilot test was 

performed where the in-house tritium sampler was modified to analyze for both HTO and 

elemental tritium. The modified sampler HTO results were significantly higher than the results 

from the in-house tritium sampler. 

The report (ChemRisk 1994) concluded: 

Tritium sampling efficiency is a source of uncertainty in the tritium emission 

estimates. Based on the limited special studies indicating a collection efficiency of 

48 ±27 percent, actual tritium emissions to the air are estimated to have ranged 

from factors of 1.3 (i.e., (0.48 + 0.27)-1 ) to 4.8 (i.e., (0.48-0.27)-1 ) times the 

reported amounts. 

Observation 3. SC&A believes the collection efficiency concern identified in SRDB Ref. ID 

8017 may apply to all the tritium exhaust samples prior to 1978. This concern should be 

investigated and resolved, and taken into consideration in the assessment of potential 

exposures of workers to tritium post-1973. 

3.5 SC&A ISSUE 5

Drawings of the bubbler are provided in SRDB 122779 and 122791, and 

handwritten notes from an interview that discusses the location of the bubblers is 

provided in SRDB 122466. With respect to bubbler location, the notes in these 

SDBRs [sic] state that, “prior to 1980, bubbler contents from exhaust plenums 

went to 123. ... In early 80’s (81 or thereabouts) they put a bubbling unit where 

components were disassembled.” The implications of these statements are that, 

prior to 1981, the bubblers may not have been placed in the optimum location for 

providing data useful for dose reconstruction. This matter requires further 

investigation and discussion. (SC&A 2014)

3.5.1 Material Provided by NIOSH that Addresses this Issue and SC&A’s Position on this 

Issue

This issue is discussed extensively as part of Issues 1, 2, and 4 and is not discussed further here.
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3.6 SC&A ISSUE 6

We would also like to hear more about the handling of metal tritides at the facility 

and the exposures associated with incidents, such as the incident that occurred in 

1977 in Room 154 where metal tritides might have been involved. (SC&A 2014)

3.6.1 Material Provided by NIOSH that Addresses this Issue and SC&A’s Position on this 

Issue

No NIOSH assessment is provided in NIOSH 2015a. 

Observation 4. This issue is not addressed in the NIOSH white paper and requires some 

discussion during the next Work Group meeting.

3.7 SC&A ISSUE 7

Table 1 of the NIOSH white paper presents a thorough summary of the reports 

addressing bubblers, but not bubbler efficiency. However, Table 1 of the white 

paper does confirm that a substantial amount of airborne tritium concentration 

data was collected following the 1973 incident that might be useful in 

reconstructing potential tritium exposures to workers post-1973 if they were 

located where workers might have been exposed to tritium. We would like to 

reiterate the need to address bubbler location. (SC&A 2014)

3.7.1 Material Provided by NIOSH that Addresses this Issue and SC&A’s Position on this 

Issue

This issue is discussed extensively as part of Issues 1 and 2 and need not be discussed here.

3.8 SC&A ISSUE 8

Page 22 of the NIOSH white paper concludes that the doses after 1975 should be 

assigned as zero for the same reasons given for 1974. We are concerned with this 

conclusion for the same reason as given above regarding 1974 exposures. 

(SC&A 2014)

3.8.1 Material Provided by NIOSH that Addresses this Issue and SC&A’s Position on this 

Issue

This issue is discussed extensively as part of Issues 1 and 2 and need not be discussed here.

3.9 SC&A ISSUE 9

Page 40 of the NIOSH May 30, 2014, white paper explains why zero dose is being 

used as a coworker tritium dose for workers in 1974 (provided in response to a 

question posed by Dr. Ziemer). For the reasons discussed previously, we believe 

the basis for assigning zero doses to workers in 1974 and also 1975 is not well 

founded because of uncertainties with respect to where the bubblers were located 
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relative to the breathing zone of the workers, and also the very limited amount of 

bioassay data collected under the 1/10 program. (SC&A 2014)

3.9.1 Material Provided by NIOSH that Addresses this Issue and SC&A’s Position on this 

Issue

This issue is discussed extensively as part of Issues 1 and 2 and need not be discussed here.

4.0 REVISION OF PART III OF APPENDIX 1: EXAMPLE RFP 

TRITIUM DOSE RECONSTRUCTION

In this example of dose reconstruction, a male employee is diagnosed with lung cancer, prostate 

cancer, basal cell carcinoma (BCC), and squamous cell carcinoma (SCC) on December 31, 2000. 

He started working on January 1, 1959 and ended his employment on December 31, 1975. 

The pre-1973 dose was assigned using the bounding estimate of 37.5 mrem/year (0.15 mrem/d 

during 250 days a year) of potential exposure prior to 1973. The worker was potentially exposed 

during 14 years to 37.5 mrem/yr or 525 mrem total dose until the end of 1972. 

For 1973, NIOSH proposed that a dose of 103 mrem should be assigned to the unmonitored 

worker. This dose was obtained using an HTO model based on the one described in Richardson 

and Dunford (2001), an intake date at April 9, 1973, and a urine sample collected on October 15, 

1973, measuring 10,000 pCi/L. This model is not appropriate for use at 187 days after exposure. 

The same authors, Richardson and Dunford, later published a paper in 2003, in which they state: 

“The ICRP HTO model has limited use in a bioassay intake estimation, as it does not possess 

components that represent the long term retention of tritium in the body that has been measured 

in bone, adipose tissue and other tissues and organs” (page 549). 

If the new draft ICRP model had been used, as described in the consulting document posted on 

the ICRP website for public comment (ICRP 2012), or David Taylor’s model (2003), which has 

a component that describes the longer retention of HTO in the body, the dose would be a little 

higher, 40 mrem to 50 mrem higher, depending on the dosimetric model applied. As this dose is 

just assigned to one year, 1973, for non-monitored workers, the difference in dose will not make 

a big difference in the probability of cancer. 

For post-1973 exposures, NIOSH concluded that the 95th percentile of the coworker study for 

1974–1975 yielded doses much less than 1 mrem for everyone. SC&A’s supports NIOSH’s 

conclusion that no workers experienced undetected exposures to tritium following the April 1973 

incident that could have resulted in doses in excess of 1 mrem/yr. Using a worst case scenario, 

for 1974 the air sample results prior to August 30 had an average of 5,343 plus or minus 4,518 

pCi/m3

 (page 19 of NIOSH 2015a). This gives a 95th percentile of about 15,000 pCi/m3, 

assuming a normal distribution, about 2.4 mrem/yr. NIOSH assumed zero doses for 1974–1975 

based on coworker urine samples and 95th percentile. SC&A concludes that the addition of a 

dose of 2.4 mrem for 1974 does not make a difference. 
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SC&A makes additional observations about the additional information and assessments provided 

in NIOSH’s follow-on report but does not disagree with the conclusion that, for both 1973 and 

beyond, NIOSH can dose reconstruct tritium doses with sufficient accuracy.

5.0 OVERALL CONCLUSIONS

For 1973 tritium exposures, SC&A concludes that, if the new ICRP model had been used, as 

described in the consulting document posted for public comment on the ICRP website, or the 

model published by David Taylor (2003), the dose would be a little higher, i.e., 40 mrem to 

50 mrem higher, depending on which dosimetric model is applied. As this dose is just assigned 

to one year, 1973, for non-monitored workers, the difference in dose estimated will not be 

substantive and will have negligible influence on the IREP probability of causation calculations.

For post-1973 tritium exposures, NIOSH concluded that the 95th percentile of the coworker 

study for 1974–1975 yielded doses much less than 1 mrem for everyone. SC&A supports 

NIOSH’s conclusion that no workers experienced undetected exposures to tritium following the 

April 1973 incident that could have resulted in doses in excess of 1 mrem/yr. Using a worst case 

scenario, for 1974 the air sample results prior to August 30 had an average of 5,343 plus or 

minus 4,518 pCi/m3 (page 19 of NIOSH 2015a). This gives a 95th percentile of about 15,000 

pCi/m3

, assuming a normal distribution, or about 2.4 mrem/yr. Although NIOSH assumed zero 

doses for 1974–1975 based on coworker urine samples and application of a 95th percentile

distribution, SC&A concludes that the conservative difference of a dose of 2.4 mrem for 1974 

falls well within the range of uncertainty, and can be considered negligible under the 

circumstances.

SC&A makes additional observations about the additional information and assessments provided 

in NIOSH’s follow-on report, but does not disagree with the conclusion that, for both 1973 and 

beyond, NIOSH can dose reconstruct tritium doses with sufficient accuracy. 

6.0 REFERENCES

ABRWH 2015. Advisory Board on Radiation and Worker Health, Rocky Flats Work Group, 

Transcript of the March 17, 2015, meeting held in Hebron, Kentucky. March 17, 2015. 

AEC (U.S. Atomic Energy Commission) n.d. Investigation of a Tritium Release Occurring in 

Building 777 on September 3–4, 1974, USACE’s Rocky Flats Plant, Golden, Colorado. n.d. 

[SRDB Ref. ID 8790]

Bogard 2013. James Bogard, Documented Communication with on Work at 

Rocky Flats. February 5, 2013. [SRDB Ref. ID 122466] 

Campbell 1986. George W. Campbell, Rocky Flats Tritium Data, Rockwell International. 

December 8, 1986. [SRDB Ref. ID 110899] 

ChemRisk 1994. Project Task 5 - Report - Estimating Historical Emissions from Rocky Flats 

1952 – 1989. March 1994. [SRDB Ref. ID 8017] 
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Dow Chemical USA 1974. Environmental Monitoring Equipment Tritium and Radioiodine 

Sampler Assembly Drawing. September 1974. [SRDB Ref. ID 111095] 

ICRP 1990. Age Dependent Doses to Members of the Public from Intake of Radionuclides – 

Part 1, International Commission on Radiation Protection, Publication 56. Ann. ICRP 20 (2). 

1990. 

ICRP 1994. Dose Coefficients for Intakes of Radionuclides by Workers, International 

Commission on Radiation Protection, Publication 68. Ann. ICRP 24 (4). 1994. 

ICRP 1997. Individual Monitoring for Internal Exposure of Workers, International Commission 

on Radiation Protection, Publication 78. Ann. ICRP 27 (3-4). 1997. 

ICRP 2012. Occupational Intakes of Radionuclides, Part II, draft report for consultation. 2012. 

Available at http://www.icrp.org/docs/Occupational_Intakes_P2_for_consultation.pdf

Lagerquist n.d. C. R. Lagerquist, Procedure for Bioassay Sampling for Body Counter and Wound 

Counter Exposure Cases. Various dates. [SRDB Ref. ID 24664] 

NCRP 2008. Management of Persons Contaminated with Radionuclides, NCRP Report No. 161. 

National Council on Radiation Protection & Measurements, Bethesda, Maryland. December 20, 

2008. 

NIOSH 2013. Rocky Flats Plant Special Exposure Cohort Petition Evaluation Report, Petition 

192, Revision 1, Division of Compensation Analysis and Support, National Institute for 

Occupational Safety and Health. September 30, 2013. 

NIOSH 2015a, Follow-up Efforts on SEC-00192, Rocky Flats Plant Tritium Issues, White Paper, 

Revision 3, National Institute for Occupational Safety and Health, Cincinnati, Ohio. December 

28, 2015. 

NIOSH 2015b. Follow-up Efforts on SEC-00192, Rocky Flats Plant Tritium Issues, White Paper, 

Revision 2, National Institute for Occupational Safety and Health, Cincinnati, Ohio. July 1, 

2015. 

ORAUT 2014. Rocky Flats Plant – Occupational Internal Dose, ORAUT-TKBS-0011-5, 

Revision 03, Oak Ridge Associated Universities Team, Cincinnati, Ohio. September 30, 2014. 

Richardson, R. B., and D. W. Dunford 2001. “Review of the ICRP Tritium and C-14 Internal 

Dosimetry Models and Their Implementation in the GENMOD-PC,” Health Physics 81(3): 289–

301. 

Richardson, R. B. and D. W. Dunford 2003. “A Biochemical-Based Model for the Dosimetry of 

Dietary Organically Bound Tritium – Part 2: Dosimetric Evaluation,” Health Physics 85(5): 

539–552. 

Rockwell International. Tritium Investigations (1973–1978). [SRDB Ref. ID 24165] 
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Rockwell International 1978. Tritium Detector Flow Diagram. June 7, 1978. [SRDB Ref. ID 

122791] 

Rockwell International 1981. Investigation Report of Tritium Release Incident January 6, 7, 

1981, Redacted, K. G. Tallman to R. E. Yoder. January 16, 1981. [SRDB Ref. ID 118366] 

Rockwell International 1982. Radiation/Contamination Surveys 1977–1981. October 15, 1982. 

[SRDB Ref. ID 111095] 

SC&A 2014. SC&A Response to NIOSH White Paper: “Follow-Up Efforts on SEC-00192 Rocky 

Flats Plant Tritium Issues,” Dated May 30, 2014, SC&A, Inc., Vienna, Virginia, and Saliant, 

Inc. Jefferson, Maryland. September 18, 2014. 

Taylor, D. M., 2003. “A Biokinetic Model for Predicting the Retention of H3 in the Human 

Body after Intakes of Tritiated Water,” Radiation Protection Dosimetry 105: 225–228. 

The Dow Chemical Company 1974. Tritium Monitoring, H. E. Bowman to W. M. Lamb. 

September 12, 1974. [SRDB Ref, ID 111267]

The Dow Chemical Company 1974. Tritium Monitoring. September 16, 1974. [SRDB Ref. ID 

112788] 
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APPENDIX A: COMPENDIUM OF AIRBORNE CONCENTRATION OF 

TRITIUM AT ROCKY FLATS BASED ON TRITIUM BUBBLER 

SAMPLES

Table A-1. 1974 Bubbler Tritium Sampling Data, Room Air Sampler – Room 452, Special 

Assembly Building 777, (Results >MDA) (SRDB Ref. ID 8790) 

Analysis 

Date 

Air 

Volume

(m3

) 

Sample 

Activity

(pCi/sample) 

Air 

Concentration

(pCi/m3) 

3-Jun 5.94 56,000 9,427.6

5-Jun 5.94 72,000 12,121.2

4-Jun 5.94 121,000 20,370.3

7-Jun 5.94 35,000 5,892.2

6-Jun 5.94 96,000 16,498.3

14-Jun 5.94 32,000 5,387.2

13-Jun 6.15 28,000 4,552.8

12-Jun 6.15 16,000 12,357.7

11-Jun 6.37 89,000 13,971.7

11-Jun 6.15 67,000 10,894.3

21-Jun 5.52 24,000 4,347.8

20-Jun 6.15 28,000 4,552.8

19-Jun 6.57 29,000 4,414.0

18-Jun 4.67 21,000 5,781.5

11-Jun 6.15 42,000 6,829.2

26-Jun 5.09 23,000 4,518.6

2-Jul 6.37 22,000 3,453.6

1-Jul 2.76 12,000 4,347.8

27-Jun 6.15 33,000 5,365.6

27-Jun 6.15 28,000 4,552.8

8-Jul 5.94 23,000 3,872.0

5-Jul 5.94 18,000 3,030.3

3-Jul 5.37 25,000 4,655.5

10-Jul 6.15 16,000 2,601.6

9-Jul 6.37 16,000 2,511.7

11-Jul 6.15 28,000 4,552.8

17-Jul 5.09 107,000 21,021.6

16-Jul 6.15 31,000 5,040.6

15-Jul 5.34 36,000 6,741.5

19-Jul 6.15 31,000 5,040.6

18-Jul 5.94 25,000 4,208.7

24-Jul 5.94 6,000 1,010.1
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Analysis 

Date 

Air 

Volume

(m3

) 

Sample 

Activity

(pCi/sample) 

Air 

Concentration

(pCi/m3) 

23-Jul 6.37 31,000 4,866.5

22-Jul 6.37 31,000 4,866.5

29-Jul 6.37 16,000 2,511.7

26-Jul 4.25 9,000 2,111.6

25-Jul 6.15 19,000 3,089.4

1-Aug 5.97 11,000 1,842.5

30-Jul 6.31 11,000 1,726.8

1-Aug 5.13 13,000 2,268.7

7-Aug 5.09 6,000 1,118.8

5-Aug 6.37 16,000 2,511.7

8-Aug 6.37 4,000 627.8

12-Aug 6.37 8,000 1,255.9

13-Aug 6.15 8,000 1,300.8

20-Aug 6.15 15,000 2,439.0

21-Aug 6.37 20,000 3,139.7

22-Aug 6.37 21,000 3,296.7

26-Aug 6.15 18,000 2,926.8

27-Aug 6.15 19,000 3,089.4

28-Aug 5.95 29,000 4,873.9

29-Aug 5.52 22,000 3,985.5

30-Aug 6.37 240,000,000 37,676,609.0

3-Sep 6.37 7.0E+06 1,098,901.1

4-Sep 6.37 54,000 8,477.2

5-Sep 5.09 26,000 5,108.0

9-Sep 5.94 18,000 3,030.3

10-Sep 6.37 20,000 3,139.7

11-Sep 5.52 16,000 2,898.5

From SRDB 8790, “Investigation of a Tritium Release 

Occurring in Building 777 on September 3–4, 1974.”

SRDB 8790 states the following (PDF page 29): 

Room Air Sampling 

Only one tritium room air sampler was installed In Building 777 at the time of the 

current tritium release problem. It is located in room 452 near the downdraft 

table entry to the Special Assembly Line. 

The applicable standard in plant Radio Concentration Guideline (RCG) Is 5 x 10 

-6 μCi/ml. Examination of daily air sample records in room 457 shows results 
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ranging from less than 1.0 x 10-3 μCi/m3, except for samples dated August 30, 

(37.7 μCi/m3) and September 3 (1.1 μCi/M3). 

The record of room air samples from June 3 to present is included as Exhibit 13. 

Room air samples are collected in a water bubbler sampler on the day shift only. 

Sampling time is from six to eight hours with sample flow rate at 2 liters/min. The 

40 hour average for the week of August 26-30 was 7.4 μCi/m3, or about 1.5 times 

the applicable RCG. 

For the week of September 3-6 (Sept 2 Labor Day) the average tritium 

concentration was approx. 2.85 x 10-1 μCI/m3 or about 6% of the RCG. 

Investigation established that the September 3 sample was collected in the same 

flask that held the August 30 sample without the flask being washed between 

samples. Thus the second sample is considered suspect because it was 

contaminated. Further, during the week of September 9, tritium contamination 

surveys conducted throughout room 452 failed to show evidence of much tritium 

contamination (less than 1.0 x 10-3 μCi per smear).

Table A-2. 1977–1981 Bubbler Tritium Sampling Data (Excluding Exhaust and Glovebox 

Samplers) (SRDB Ref. ID 111095) 

Building Location 

(Room or ID)

Analysis 

Date

Analytical 

Result 

(pCi/m3

) 

777 452 Downdraft 4/1/1977 ≤ 60

777 Rm 452 Col J-23 4/1/1977 50

777 452 Downdraft 4/4/1977 —

777 Rm 452 Col J-23 4/4/1977 —

777 452 Downdraft 4/6/1977 60

777 Rm 452 Col J-23 4/6/1977 90

777 452 Downdraft 4/11/1977 10

777 Rm 452 Col J-23 4/11/1977 20

779A Rm 154 1/3/1978 ≤ 60

777 452 Downdraft 1/4/1978 20

777 Rm 452 Col J-23 1/4/1978 ≤ 10

881 283 1/4/1978 ≤ 10

779A Rm 154 1/4/1978 ≤ 90

771 181 1/5/1978 ≤ 40

771 305 1/5/1978 ≤ 20

771 Rm 146 1/5/1978 ≤ 10

774 220 1/5/1978 ≤ 20

777 452 Downdraft 1/6/1978 30

777 Rm 452 Col J-23 1/6/1978 40

881 283 1/6/1978 20

779A Rm 154 1/6/1978 90

777 452 Downdraft 1/9/1978 ≤ 40
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Building Location 

(Room or ID)

Analysis 

Date

Analytical 

Result 

(pCi/m3

) 

777 Rm 452 Col J-23 1/9/1978 ≤ 30

779A Rm 154 1/9/1978 120

777 452 Downdraft 1/2/1979 60

777 Rm 452 Col J-23 1/2/1979 ≤ 40

777 452 Downdraft 1/3/1979 80

771 181 1/4/1979 ≤ 50

771 Rm 146 1/4/1979 ≤ 50

771 Rm 174 1/4/1979 ≤ 30

777 Rm 452 Col J-23 1/5/1979 60

779A Rm 154 1/5/1979 170

374 First Floor 1/8/1979 ≤ 80

559 102 1/8/1979 80

777 Rm 452 Col J-23 1/8/1979 ≤ 40

779A Rm 154 1/8/1979 ≤ 120

374 First Floor 1/9/1979 ≤ 50

779A Rm 154 1/2/1980 ≤ 70

779A Rm 154 1/2/1980 100

777 Rm 452 Col J-23 1/4/1980 70

779A Rm 154 1/4/1980 170

777 452 Downdraft 1/7/1980 ≤ 50

777 Rm 452 Col J-23 1/7/1980 ≤ 50

881 283 1/7/1980 ≤ 50

779A Rm 154 1/7/1980 ≤ 120

777 430 K-15 1/9/1980 120

777 452 Downdraft 1/9/1980 150

777 Rm 452 Col J-23 1/9/1980 ≤ 70

777 430 G-18 1/5/1981 80

777 452 Downdraft 1/5/1981 ≤ 70

777 Rm 452 Col J-23 1/5/1981 ≤ 80

881 283 1/5/1981 ≤ 80

779A Rm 154 1/5/1981 ≤ 170

779A Rm 154 1/5/1981 ≤ 170

779A Rm 154 1/5/1981 170

779A Rm 154 1/5/1981 ≤ 120

777 430 G-18 1/7/1981 1780

777 452 Downdraft 1/7/1981 440

777 Rm 452 Col J-23 1/7/1981 540

779A Rm 154 1/7/1981 170

777 430 G-18 1/8/1981 7920

777 430 G-18 1/9/1981 1720

777 452 Downdraft 1/9/1981 510

777 Rm 452 Col J-23 1/9/1981 640

881 283 1/9/1981 ≤ 80

779A Rm 154 1/9/1981 90

777 430 G-18 1/12/1981 180
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Building Location 

(Room or ID)

Analysis 

Date

Analytical 

Result 

(pCi/m3

) 

777 452 Downdraft 1/12/1981 ≤ 40

777 Rm 452 Col J-23 1/12/1981 ≤ 80

881 283 1/12/1981 ≤ 60

779A Rm 154 1/12/1981 ≤ 120

771 Rm 146 12/16/1981 0

771 Rm 146 12/16/1981 0

771 Rm 149 12/16/1981 0

771 Rm 174 12/16/1981 0

777 430 G-18 12/16/1981 0

777 452 Downdraft 12/16/1981 90

777 Rm 452 Col J-23 12/16/1981 90

777 Rm 465 12/16/1981 -80

771 Rm 146 12/18/1981 0

771 Rm 149 12/18/1981 60

771 Rm 174 12/18/1981 -80

777 430 G-18 12/18/1981 0

777 452 Downdraft 12/18/1981 0

777 Rm 452 Col J-23 12/18/1981 -80

777 Rm 465 12/18/1981 80

881 225 12/18/1981 0

881 Rm 15 12/18/1981 0

771 Rm 146 12/22/1981 0

771 Rm 149 12/22/1981 0

771 Rm 174 12/22/1981 0

774 Rm 441 12/22/1981 0

777 430 G-18 12/22/1981 0

777 452 Downdraft 12/22/1981 0

777 Rm 452 Col J-23 12/22/1981 0

777 Rm 465 12/22/1981 0

779A Rm 154 12/22/1981 60

771 Rm 146 12/23/1981 80

771 Rm 149 12/23/1981 0

771 Rm 174 12/23/1981 0

774 Rm 441 12/23/1981 80

777 430 G-18 12/23/1981 80

777 452 Downdraft 12/23/1981 0

777 Rm 452 Col J-23 12/23/1981 0

777 Rm 465 12/23/1981 0

881 Rm 15 12/23/1981 0

779A Rm 154 12/23/1981 90
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SRDB Ref. ID 118366 states the following: 

On January 6 and 7, 1981, a release of tritium occurred in Building 777 to 

qlovebox exhaust Plenums 205 and 206, and subsequently to the environment. 

The release occurred from tritium contaminated materials that were returned to 

the glovebox system for part verification.

SRDB 118366 also states: 

From the room air H20 bubbler sample located at Glovebox 452, data indicated 

that one, or both, cans, when received at Glovebox 45l.on January 6, 1981, were 

leaking. This sample for the time period January 5 to January7 showed a 

concentration in the room air of 1720 pCi/m3. This sample normally shows MDA 

(80 to 120 pCi/m3

).

Table A-3. Building 777 Bubbler Tritium Sampling Data – January 5 to 12, 1981 

(Excluding Exhaust and Glovebox Samplers)

Location 

(Room or ID) 

Analysis 

Date

Analytical 

Result 

(pCi/m3)

430 G-18 1/5/1981 80

452 Downdraft 1/5/1981 ≤ 70

Rm 452 Col J-23 1/5/1981 ≤ 80

430 G-18 1/7/1981 1780

452 Downdraft 1/7/1981 440

Rm 452 Col J-23 1/7/1981 540

430 G-18 1/8/1981 7920

430 G-18 1/9/1981 1720

452 Downdraft 1/9/1981 510

Rm 452 Col J-23 1/9/1981 640

430 G-18 1/12/1981 180

452 Downdraft 1/12/1981 ≤ 40

Rm 452 Col J-23 1/12/1981 ≤ 80

Source: SRDB Ref. ID 8790, Exhibit 13, pages 87–89: