Rocky Flats Plant 

SEC-00192

David Kotelchuck, 

RFP WG, Chairperson

Advisory Board on Radiation and Worker 

Health

March 23, 2017

Naperville, Illinois
Working Group: Rocky Flats Plant 

 David Kotelchuck (Chairperson)

 Bill Field 

 Wanda I. Munn

 Phillip Schofield
Petition Overview 

• August 23, 2011: NIOSH received an 

83.13 petition for period of 4/1/1952 

to 12/31/1989 covering tritium 

exposures. 

• Feb. 9, 2012: Petition qualified for 

evaluation (SEC-00192) and petition 

period extended to 12/31/2005. 
Petition Overview -contd.

• October 17, 2013: Board extended 

existing SEC-0030 (up to 1966) to cover 

all employees with at least 250 

workdays between April 1, 1952 and 

Dec. 31, 1983.

• Board then voted to extend 

investigations for SEC-00192 from 

12/31/83 to 12/31/2005 in order to:
Petition Overview -contd.

1. Evaluate the use and exposure potential for 

Mg- Th alloy at Rocky Flats

2. Continue to evaluate 1984-1988 period for 

Neptunium exposure potential

3. Resolve open questions with SC&A and the 

work group concerning tritium

4. Examine implications of Data Falsification 

issues

5. Examine exposures at the Critical Mass Lab
1. Mg-Th Alloy

• Issue raised in 2007 under SEC-0030. 

Allegedly alloy shipped to RFP for use in 

plates to bullet-proof military trucks (2-4% Th

typical).

• As part of SEC-00192 examination, NIOSH in 

2013 carried out another review of the Site 

Research Database (SRDB) for an RFP/Mg-Th

link, but found no corroborating evidence for 

such a link.
Mg-Th Alloy-contd.

• However workers at Dow-Madison plant 

reported shipping Mg-Th plates to RFP. 

Dow-Madison worked with plates between 

1962 and 1975.

• NIOSH asserted in its report that workers 

there were apparently not aware of other 

Dow facilities in Denver area, and may have 

delivered Mg-Th to these instead.

• Again no corroborating RFP links found.
Mg-Th Alloy-contd.

• On 5/31/13 NIOSH was informed that an RFP 

worker (anonymous) reported that Mg-Th was 

used at the plant.

• NIOSH further reviewed RFP databases but still 

could not find corroborating documentation.

• NIOSH concluded that there was “no 

corroborating evidence” for the use of Mg-Th at 

the RFP site.

• Additionally NIOSH observed: If Mg-Th alloy was 

sent to the RFP, this took place between 1962 

and 1975, during the covered SEC period. 
Mg-Th Alloy-contd.

However SC&A had a different perspective:

• The workers interviewed both by NIOSH 

and SC&A provided a high level of “clarity 

and detail”. They specifically named 5 

different Mg-Th alloy specifications, only 

two of which were searched for.

• Rather than “confusion”, “it is just as 

‘possible’ that the worker had it right all 

along.”

• SC&A conclusion: “the receipt and use of 

Mg-Th alloy material at RFP remains 

inconclusive”.
Mg-Th Alloy-contd.

Faced with this difference, the RFP Working Group 

needed to decide on the path forward on this issue. In 

this regard,

• SC&A noted that 400 boxes of RFP records sit at 

LANL according to DOE and would have to be handsearched. Estimated search time: 2 years.

• Also in the SC&A report re lack of Mg-Th records, a 

DOE project mgr noted that 2%–4% thorium in MgTh alloy at RF may not have been considered to be a 

reportable quantity.
Mg-Th Alloy-contd.

On 3/17/15 the WG decided not to ask NIOSH or 

SC&A to pursue this issue further and to close this 

issue. Our reasons:

1. The failure of the intensive, years-long searches 

for documentation at the plant and agency 

levels. 

2. Consideration of current limitations on NIOSH 

resources of staff time and funding.

NOTE: The vast majority of cancers during yrs. of 

possible Mg-Th use are compensable under the 

existing SEC. (Only those with non-compensable 

cancers, not in SEC, might be negatively affected.)
Mg-Th Alloy-contd.

On 2/6/17 co-petitioners released the transcript 

(via FOIA) of a 2013 interview with an RFP worker 

who reported use of plates btw 1984 and 1989 

that he believed might have been Mg-Th (“It’s 

hard to say.”). Co-petitioners asked that the 

interview to be re-opened.

At its 2/9/17 meeting, WG with input from NIOSH 

and SC&A decided that the transcript had 

previously been evaluated in the context of all the 

information gathered and did not warrant further 

reconsideration or elaboration. 

Thus this issue remains CLOSED.
2. Neptunium-237

• A NIOSH search concluded that Np237 was used at RFP after the 1983 

SEC date, perhaps until 1988:

• “..evidence points to a series of 

discrete tasks performed from 1962 

through 1983, involving a few gms. 

to a few hundred gms”, usually at 

request of other DOE facilities. Max: 

300 gms in 1966.
Neptunium-237-contd.

• The only processing operation in 

the post-1983 period involving 

Neptunium was the PlutoniumNeptunium Separation and 

Residue recovery operation from 

late 1985 to the end of 1987. 

• This was a glove box operation 

involving 5 operators and one 

engineer.
Neptunium-237-contd.

• With a Pu:Np mass ratio of 6.4 and 

the far greater specific activity of 

Pu, Np operations and later waste 

clean-up were monitored via Pu air 

sampling, contamination surveys 

and bioassays (urine & body 

counts), which were consistently 

implemented in the post-1983 

period.
Neptunium-237-contd.

• SC&A studies independently confirmed the 

results of the NIOSH White Paper.

• CONCLUSION: Only one processing operation 

in the post-1983 period involved neptunium, 

and the co-presence of neptunium with 

plutonium enabled radiological monitoring to 

account for any neptunium exposure 

component in a claimant-favorable manner. 

CLOSED. 
3. Tritium Exposure 

• Was the original basis for accepting SEC-00192.

• Internal doses are the main health concern from 

from tritium (H3).

• Prior to the 1970’s the RFP radiological program 

did very little monitoring for tritium because 

they believed there was a limited tritium 

exposure potential. However a 1973 incident 

revealed that returned triggers (pits) containers 

could emit 500-2000 Ci of tritium.
Tritium Exposure-contd.

As a result a series of changes were implemented, 

including:

• Increased numbers of H3 bubblers and swipe samples

• Air sampling upon opening incoming containers of 

used pits

• Urine samples for 250 workers thought to be the 

most affected, followed two years later by sampling 

only among those in job-specific categories because 

the earlier results showed no excess exposure levels

• 10% of urine samples for Pu were tested for tritium

RESULT: Greatly reduced levels of H3 exposure by the 

1980’s. 
Tritium Exposure-contd.

• Since virtually all RFP workers before 1983 are 

covered by SEC-0030, the crucial issue for 

NIOSH/ORAU, SC&A and the RFP WG was 

whether the post-1983 tritium exposure control 

program was adequate and individual H3 

exposures appropriately assessed.

• After extensive group discussion about the 

placement of bubblers, their efficacy and H3 

sampling procedures, the WG agreed that the 

exposure control program after 1983 was 

adequate to protect workers exposed to H3.
Tritium Exposure-contd.

• Partial dose reconstructions for workers before 1973 will be 

assessed as chronic doses based on measurements just after the 

1974 H3 incident (37.5 mr/yr), which are believed to be claimant- friendly over-estimates.

• Exposure measurements taken in 1975 and thereafter were 

consistently found to be less than 1 mr/yr, due to the control 

measures enacted after 1973 and the short lifetime of H3 (12.3 

yrs). 

The WG agreed that H3 exposure at RFP does not add 

materially to the radiation exposure burden of plant 

workers post-1983 and thus of itself does not 

constitute a basis for an SEC category beyond 1983. 

CLOSED.
4. Data Falsification Issues

An FBI raid was conducted at RFP in 1989 concerning alleged 

data falsification, improper bioassay processing and 

document destruction. Also in 1989 a related DOE study was 

conducted. However the FBI did not release the redacted 

interview transcripts requested by NIOSH until 2015. 

1. NIOSH and SC&A interviewed a number of RFP 

employees, including one who reported being 

ordered to destroy records. NIOSH reported no 

loss in “essential records” which would interfere 

with radiation dose reconstruction, nor did it find 

evidence of relevant data falsification. SC&A 

concurred. 
Data Falsification Issues-contd.

2. Another interviewee made statements 

about the inadequacy of fume hoods, stack 

samples and improper handling and/or 

preparation of environmental samples. 

“From a radiological perspective, NIOSH 

finds no scientific basis for concluding that 

the issues raised regarding environmental 

samples would compromise radiological 

count results” (emphasis added).
Data Falsification Issues-contd.

3. Another interviewee raised the issue of 

dosimetry technicians writing down dose 

rate information in pencil, which might 

allow others later to direct changes in these 

data. This might impact results recorded for 

field survey instruments, but the primary 

sources of dose reconstruction data are 

personnel dosimeters and bioassays, 

assessed in labs.
Data Falsification Issues-contd.

4. SC&A reviewed eight documents mentioned 

in the NIOSH White Paper. It concluded “the 

documents were concerned with other 

aspects of RFP operations or environmental 

issues, rather than data falsification, record 

destruction, or bioassay data, that would 

potentially impact the ability to perform 

adequate dose reconstructions.”
Data Falsification Issues-contd.

• Based on its interviews, analyses and 

evaluation of the 2015 FBI report, NIOSH 

concluded that “there exists a sufficient 

quantity of individual external monitoring 

data to support the assessment of RFP 

personnel external doses.” SC&A agreed with 

this conclusion. 
Data Falsification Issues-contd.

• In addition to its basic support of the 

conclusions of the NIOSH White Paper, SC&A 

expressed concern that data used to generate 

radionuclide intakes might be impacted by 

the environmental sampling/data issues that 

surfaced after both the 1989 FBI raid and the 

1989 DOE investigation.

• The RFP WG having read the associated White 

Papers and heard the presentations agreed 

with the NIOSH conclusions and referred the 

env./occ. linkage issue to the Subcommittee 

on Procedures Review.
Data Falsification Issues-contd.

• Claimant representatives wrote a detailed response 

(9/18/15) to the NIOSH White Paper: “NIOSH combines all of 

the issues raised by the petitioners and their relationship to 

Building 123. Each of the issues raised are separate 

concerns. Some concerns may be related to Building 123 but 

not all of the issues are. Therefore, each of the issues needs 

to be addressed on an individual basis. It is the petitioners’ 

position that the problems associated with each individual 

concerns (sic) is sufficient for NIOSH to determine they 

cannot reconstruct dose with sufficient accuracy.” 

• Their response itemized six different areas of concern. On 

11/30/15 NIOSH responded to each of these. For example:
Data Falsification Issues-contd

Records Destruction: 

• 1. Petitioner concern: Relatively low nr of 

urine samples (10,468 in 1984) “equates to 

less than two samples per employee” that 

year. 

• NIOSH: “incorrectly assumes that every 

worker employed at RFP in 1984 had a 

potential for internal exposure”. Petitioner 

metric “not appropriate”. 
Data Falsification Issues-contd

• Records Destruction (cont’d):

• 2. Petitioner concern: “No fecal samples 

listed for years 1980 through 1988 – eight full 

years.” Nr of fecal samples for pre-1988 “very 

important”.

• NIOSH: Fecal samples “not necessary to 

bound inhalation intakes”. Urine analyses can 

also be used. However “more than 1000 fecal 

sample results” available for 1980-1988.
Data Falsification Issues-contd

• “Based on its review of the rebuttal 

document from the petitioners, NIOSH’s 

concludes that no new information has been 

presented that impacts its ability to bound, 

or reconstruct with sufficient accuracy, the 

dose for the class evaluated in the SEC-00192 

RFP.” The RFP WG concurs with this 

conclusion. CLOSED.
5. Critical Mass Lab

Operations in the Critical Mass Lab (CML) took 

various assemblies and radioactive materials to 

criticality levels. In addition to emissions from the 

criticality studies, the NIOSH White Paper issued 

6/9/15 noted: “Radioactive materials at the CML 

included the nuclear fuels and sealed radioactive 

sources used in criticality experiments. Fission and 

activation products generated in the fuels, building 

materials and fixtures as a result of the nuclear 

criticality experiments conducted there are an 

additional source of radiological exposure.” 
Critical Mass Lab-contd.

This White Paper concluded: External radiation 

exposure to CML personnel from criticality expts. is accounted for by Rocky Flats’ personnel 

dosimetry program, which assigned radiation 

dosimeters to all CML workers. This program also 

included periodic bioassays (urinalysis and body 

counts) that focused primarily on identifying 

uranium and plutonium intakes. Also NIOSH found 

“no significant personnel dose” to CML workers 

from mixed fission & activation products over the 

lifetime of the lab. 

SC&A agreed and the WG accepted this Paper. 
Critical Mass Lab-contd.

• However on the 7/14/15 RF WG conference 

call, the last surviving of 3 senior scientists at 

CML (1964-1986) joined the discussion and 

expressed strong disagreement with the 

conclusions of the NIOSH White Paper. He 

requested a personal interview at a later 

time, which was agreed to and conducted on 

10/13/15.
Critical Mass Lab-contd.

• During the interview this CML scientist argued 

that no one could bound the neutron flux in the 

lab’s near criticality experiments. He disputed 

NIOSH’s ability to calculate upper bounds on the 

neutron flux via reactors’ energy output during 

the criticality experiments.

• He also asserted that radiation levels at CML 

were not properly documented, and 

• That the RFP personnel dosimetry program only 

performed lung counts, not full body counts on 

the lab’s 30-35 employees, and conducted 

urinalyses irregularly.
Critical Mass Lab-contd.

• In addition to exposures to its full-time 

employees, this CML scientist reported that 

during the 1980’s typically 100-200 non-CML RF 

employees entered the lab annually to observe 

ongoing experiments.

• At the conclusion of this discussion, NIOSH staff 

agreed to review existing data, extend its search 

and issue an updated White Paper on CML. 

Included in this effort was a (time consuming) 

capture of CML data from Los Alamos National 

Lab (LANL).
Critical Mass Lab-contd.

A Reassessment White Paper was issued on 

11/28/16. 

• NIOSH found that CML staff had on five 

occasions satisfactorily assessed thermal power 

and neutron flux, and the power in all cases was 

less than the 10 mW estimated in its 7/14/15 

NIOSH White Paper.

• Routinely collected data was found for external 

exposures monitored via personnel badges and 

daily radiation surveys at control points. 

Potentially contaminated surfaces were checked 

regularly for alpha radiation via tissue smears . 
Critical Mass Lab-contd.

• Internal exposures resulting from inhalation and 

ingestion of airborne dusts and resuspension from 

contaminated surfaces were assessed via bioassays 

(with enough data to reasonably estimate internal 

exposures).

• Thus after reassessment NIOSH again concluded that

“no significant personnel dose to Rocky Flats workers 

or contractors resulted from the generation of fission 

or activation products in the uranyl nitrate fuel or 

resuspended contamination from fuel spills as a result 

of criticality experiments conducted at CML over its 

lifetime.” CLOSED.
Additional Issue: Cobalt-60 Exposure

• In Spring 2015 claimants raised new concerns about 

radiation exposure from the 600 Ci Cobalt-60 source 

at RFP, and presented information from DOE (via 

FOIA) as well as employee testimony alleging lack of 

proper exposure protection during removal of this 

source from RFP.

• A NIOSH White Paper on sealed sources was issued 

on 7/8/15. At the 10/28/15 RFP WG meeting, NIOSH 

reported that proper, standard radiation 

measurements were made during Co-60 use and 

removal, and only background levels of 

contamination were found. CLOSED.
Issues Resolution: RFP SEC-00192

 At its 10/17/13 meeting the Board charged the RF WG to 

investigate the following issues for a possible SEC beyond 

12/31/83 to:

1. Evaluate the use and exposure potential for Mg-Th alloy at Rocky Flats – CLOSED 

2. Continue to evaluate 1984-1988 period for 

Neptunium exposure potential – CLOSED 

3. Resolve open questions with SC&A and the work group concerning tritium – CLOSED 

4. Examine implications of Data Falsification issues – CLOSED, 

with referral to Proc. Review SC to examine any possible env. impact on dose reconstruction calculations

5. Examine exposures at the Critical Mass Lab – CLOSED, and

WG examined exposures during Co-60 use & removal - CLOSED 
Recommendation RFP SEC-00192

• For the period January 1, 1984 – December 

31, 2005, the RFP Working Group finds that 

radiation dose estimates can be adequately 

reconstructed for individual claimants, and 

recommends that this class not be added.
Questions?