Draft 

ADVISORY BOARD ON 

RADIATION AND WORKER HEALTH 

National Institute for Occupational Safety and Health 

Preliminary Issues from SC&A’s Review of NIOSH’s Evaluation Report 

for the Weldon Spring Site, Weldon Spring, Missouri, 

Special Exposure Cohort Petition SEC-00143 

 

Contract No. 200-2009-28555 

SCA-SEC-2010-0015, Revision 0

Prepared by 

Ron Buchanan, PhD, CHP 

S. Cohen & Associates 

1608 Spring Hill Road, Suite 400 

Vienna, Virginia 22182 

Saliant, Inc. 

5579 Catholic Church Road 

Jefferson, Maryland 21755 

October 2010 

Disclaimer 

This document is made available in accordance with the unanimous desire of the Advisory Board 

on Radiation and Worker Health (ABRWH) to maintain all possible openness in its 

deliberations. However, the ABRWH and its contractor, SC&A, caution the reader that at the 

time of its release, this report is pre-decisional and has not been reviewed by the Board for 

factual accuracy or applicability within the requirements of 42 CFR 82. This implies that once 

reviewed by the ABRWH, the Board’s position may differ from the report’s conclusions. Thus, 

the reader should be cautioned that this report is for information only and that premature 

interpretations regarding its conclusions are unwarranted.
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Document No. 

SCA-SEC-2010-0015 

Effective Date: 

Draft –October 28, 2010 

S. COHEN & ASSOCIATES:

Technical Support for the Advisory Board on 

Radiation & Worker Health Review of 

NIOSH Dose Reconstruction Program Revision No. 

0 

Preliminary Issues from SC&A’s Review of NIOSH’s 

Evaluation Report for the Weldon Spring Site in 

Weldon Spring, Missouri, Special Exposure Cohort 

Petition SEC-00143

Page 2 of 30 

Task Manager: 

________________________ Date: ___________ 

Ron Buchanan, PhD, CHP 

Supersedes: 

0 

Project Manager: 

________________________ Date: ___________ 

John Mauro, PhD, CHP 

Reviewer: 

 Joseph Fitzgerald 

Record of Revisions 

Revision 

Number 

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0 (Draft) 10/28/2010 Initial issue 

11/15/2010 Document has been cleared for Privacy Act-protected information as written. Author’s 

name added to cover page, Task Manager’s name corrected, and reviewer added on 

page 2. 
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TABLE OF CONTENTS 

Abbreviations and Acronyms ..........................................................................................................4 

Introduction and Summary ..............................................................................................................6 

1.0 Accuracy of Records not Sufficiently Verified ...................................................................7 

1.1 Summary of Lack of Verification of Accuracy of Records.....................................7 

2.0 Lack of Personnel Contamination/Egress Monitoring.........................................................9 

2.1 Summary of Lack of Contamination/Egress Monitoring.......................................10 

3.0 Lack of Information for Workers During 1967 .................................................................11 

3.1 Summary of Lack of Workers’ Information for 1967 ...........................................12 

4.0 Inadequate Radon/Thoron Determination for Monitored and Unmonitored Workers......14 

4.1 .....................................................................................................................14 Radon

4.2 ....................................................................................................................15 Thoron

4.3 Summary of Inadequate Radon and Thoron Determination..................................16 

4.3.1 .........................................................................................................16 Radon

4.3.2 ........................................................................................................16 Thoron

5.0 Inadequate Recommendation for Assigning Recycled Uranium Dose..............................17 

5.1

..................................................................................................20 

Summary of Inadequate Recycled Uranium Dose Assignment 

Recommendations

6.0 Neutron Dosimetry Records not Available........................................................................22 

6.1 Summary of Neutron Dosimetry Records not Available.......................................22 

7.0 Quarry and Raffinate Pits Exposures Inadequately Addressed .........................................23 

7.1 Summary of Quarry and Raffinate Pits Exposure Issues.......................................23 

8.0

............................................................................................................25 

Insufficient Investigation & Documentation of Off-normal Situations and 

Accidents/Incidents

8.1 Summary of Insufficient Investigation ..................................................................25 

9.0 Geometry and Extremity Issues not Addressed.................................................................27 

9.1 Summary of Geometry and Extremity Issues........................................................27 

References......................................................................................................................................28 
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ABBREVIATIONS AND ACRONYMS 

Advisory Board Advisory Board on Radiation and Worker Health 

or ABRWH 

AEC Atomic Energy Commission 

Bq Becquerel 

BZ Breathing zone 

CER Center for Epidemiologic Research 

CFR Code of Federal Regulations 

Ci Curie 

DOE Department of Energy 

DR Dose reconstruction 

DWA Daily Weighted Average 

EE Energy Employee 

EEOICPA Energy Employees Occupational Illness Compensation Program Act of 2000 

ER Evaluation Report 

FMPC Feed Materials Production Center 

gm gram 

HPS Health Physics Society 

k kilo 

l liter 

m3 cubic meter 

MCW Mallinckrodt Chemical Works 

MCWUD MCW Uranium Division 

mrem millirem 

mrep millirep 

MT metric ton 

NIOSH National Institute for Occupational Safety and Health 

ORAUT Oak Ridge Associated Universities Team 

pCi picocurie 

ppb parts per billion 

rem Roentgen equivalent man 

rep Roentgen equivalent physical 
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NOTICE:

RF release fraction 

RU recycled uranium 

SC&A S. Cohen and Associates 

SEC Special Exposure Cohort 

SRDB Site Research Database 

TBD Technical Basis Document 

TIB Technical Information Bulletin 

TRU Transuranic 

TSR, Inc. Thompson-Stearns-Rogers 

WL working level 

WLM Working Level Month 

WS Weldon Spring 

WSCP Weldon Spring Chemical Plant 

WSP Weldon Spring Plant 

WSS Weldon Spring Site 

Y Year 
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INTRODUCTION AND SUMMARY 

At the Advisory Board on Radiation and Worker Health (Advisory Board) meeting held in 

Niagara Falls, New York, on May 19, 2010, the Advisory Board authorized SC&A to perform a 

focused review of the Weldon Spring Site (WSS) Special Exposure Cohort (SEC) Petition 

(NIOSH 2009b) and National Institute for Occupational Safety and Health (NIOSH) Evaluation 

Report (ER) (NIOSH 2010). The SEC petition requested that the time period include January 1, 

1957, through December 31, 1966. NIOSH’s ER of April 16, 2010, recommends that a time 

period of January 1, 1957, through December 31, 1967, be evaluated for SEC status. This report 

presents SC&A’s preliminary identification of potential Weldon Spring Site SEC issues with 

regard to this matter, based on a review of SEC petition #00143, NIOSH’s ER of SEC-00143, 

the Weldon Spring Site Profile, SC&A’s review report of the Weldon Spring Site Profile, worker 

interviews (SC&A 2009), and related documents. 

In reviewing these documents, SC&A found that NIOSH’s ER addressed many of the important 

issues raised in the SEC, and several related issues. Useful data were provided for consideration, 

and several methods were recommended for use in situations where data were lacking. NIOSH 

addressed the issues from several directions and recommended solutions applicable to dose 

reconstruction (DR). SC&A found that considerable research had gone into bases of the ER, and 

that it is a helpful step in the SEC process. However, to continue the SEC process, SC&A has 

identified several important areas that need further investigation. SC&A finds that for the period 

of 1957–1966 at the WSS, there is inadequate verification of the accuracy of the records and 

applicability of the air monitoring data, inadequate contamination/egress control, and inadequate 

recommendations for radon and thoron intakes to allow the feasibility of estimating, with 

plausible accuracy, the maximum radiation dose, or establishing the individual doses, for skin 

exposures and intakes to a significant number of the production and non-production workers 

using technically sound methods. Additionally, there are essentially no direct data available to 

reconstruct external or internal doses to workers for the year of 1967. SC&A also found that the 

methods recommended for assignment of doses from recycled uranium (RU), neutrons, the 

quarry/raffinate pits, exposure geometry, and off-normal situations are inadequate as well.
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1.0 ACCURACY OF RECORDS NOT SUFFICIENTLY VERIFIED 

In the Evaluation Report (ER), the National Institute for Occupational Safety and Health 

(NIOSH) presents the following information concerning the accuracy and applicability of the 

present data used for dose reconstruction (DR) purposes at the Weldon Spring Site (WSS). 

(a) Internal – NIOSH presents the availability of bioassay records on page 35 of the ER and 

a comparison of WSS hardcopy uranium urinalysis data to the Center for Epidemiologic 

Research (CER) database on page 49, and concludes that the bioassay data are accurate 

for 1957–1967. 

(b) Air data – The ER provides breathing zone (BZ) and area air sampling data sources on 

page 40 for uranium (1958–1966) and pages 41–45 for thorium (1963–1966), and 

recommends using TIB-5000 (Battelle 2007) and TIB-6000 (Battelle 2006); no specific 

intake values are provided in the ER. 

(c) External – NIOSH briefly addresses the availability of external dosimetry results on 

pages 46 and 52 of the ER, and concludes that the available external dosimetry 

monitoring data are available in sufficient quantity and quality to adequately represent 

external beta and photon dose for the Weldon Spring Plant class under evaluation for the 

period from January 1, 1957, through December 31, 1967. 

(d) Coworker – NIOSH does not discuss coworker models for the WSS in the ER or the 

technical basis documents (TBDs); however, it is stated on pages 63 and 67 of the ER 

that exposures for unmonitored workers can be bound by using the monitored workers’ 

data for both external and internal exposures. The issue of the representativeness of 

cohort bioassays for groups is not addressed, nor how this data would be used in a 

coworker model. 

1.1 SUMMARY OF LACK OF VERIFICATION OF ACCURACY OF RECORDS 

SC&A did not find that the accuracy and applicability of the data available for DR had been 

adequately verified by NIOSH. The following is a summary of the issues in each major area. 

(a) Internal – SC&A did not find that NIOSH’s comparison was sufficient to establish the 

accuracy of the internal dose of record. Comparison of hardcopies to the CER database 

does not provide sufficient evidence that the records used by the dose reconstructor are 

adequate and have accurately survived the transfer of data over the years. Hardcopies 

compared to the files that would be provided to the dose reconstructor are necessary for 

validation. The sequence of databases and the verification of accurate transfer of 

bioassay data between these databases are necessary to demonstrate that the data received 

by the dose reconstructor are traceable to the original data. 

(b) Air data – SC&A reviewed the data sources and found that they do contain periodic air 

sampling data for uranium and thorium, as stated in the ER. However, the ER does not 

provide any further evaluation of the adequacy or accuracy of this data, nor justification 
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for using Daily Weighted Average (DWA) values, or application details for DR purposes. 

The use of DWA values has brought up issues at other Department of Energy (DOE) 

sites, some of which are expanded on in the Mallinckrodt Chemical Works (MCW) 

Downtown site review (SC&A 2005). This issue is applicable to a number of Atomic 

Energy Commission (AEC)/DOE sites and should be investigated in conjunction with 

methods recommended for other sites; especially those at the MCW downtown site, 

Fernald, and the WSS. SC&A’s review of the related documents (Adam & Strom 2008, 

NIOSH 2009a, and NIOSH 2010) did not find that the Adam & Strom 2008 Health 

Physics Society (HPS) article supported the applications and assumptions in NIOSH’s 

ER (NIOSH 2010) and the Morris article (NIOSH 2009a) for the WSS. SC&A will issue 

a memo outlining these differences. 

(c) External – While the number of badges and the average gamma/beta doses are listed, 

there is no verification of external doses of record provided. Additionally, there are no 

data presented for 1967, as will be detailed in a following SEC issue. As was true for 

bioassay data, the sequence of databases and the verification of accurate transfer of 

external dose data between these databases are necessary to demonstrate that the data 

received by the dose reconstructor are traceable to the original data. 

(d) Coworker – There appears to be a large amount of both bioassay and external dose data; 

however, until the accuracy of the data can be determined (as outlined in previous issues), 

it is not applicable for the creation of an external dose or internal intake coworker 

database for unmonitored workers. Additionally, the proposed structure of the database 

and its applicability need to be addressed, including how the cohort bioassays would be 

used. 
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2.0 LACK OF PERSONNEL CONTAMINATION/EGRESS 

MONITORING 

Neither the WSS TBDs nor NIOSH’s ER mentioned the lack of monitoring equipment and 

procedures to check workers for contamination in the work places and upon leaving the 

controlled areas. SC&A could not locate any documentation to verify if such procedures and 

equipment were used at the WSS during the operating period of 1957–1966, or during 1967. At 

that time, uranium was considered to be mostly a chemical hazard and control measures were 

mainly based on chemical toxicity limits, not radiological limits [ORAUT-TKBS-0028-5, 

page 11 (ORAUT 2005e)]. During worker interviews, SC&A did not find that the workers 

recalled any established egress monitoring, either between the operations areas and the nonoperations areas (cafeteria, administration offices, labs, maintenance facilities, sidewalks, storage 

yards, grounds, etc.), or when leaving the plant site (guard shack, parking lots). Workers did 

indicate, and documents support, that they were required to change clothing when entering and 

leaving the operations areas (some workers showered, but this policy does not appear to have 

been strictly enforced); however, there is no evidence that the workers were routinely checked 

for contamination before leaving the controlled areas to ascertain that they were not 

contaminated. Documents indicate that some area monitoring (i.e., with portable survey 

instruments and swipes) and cleanups were performed to keep some surfaces below certain limits 

(MCW 1965, page 20), but there is no indication that survey instruments or hand/foot monitoring 

stations were available and routinely used to monitor workers as they left the operational areas or 

the WSS. Contamination was apparently commonplace inside the process areas, as evident by a 

statement in MCW Uranium Division (MCWUD) Summary of Health Protection Practices

(MCW 1965, page 20), which states that, “Inside the process locations, surface contamination 

measurements have little significance.” Contamination was apparently common on workers, as 

described in a 1960 WSS document (Burr 1960): 

[The EE’s] shoes and [the EE’s] gloves were especially loaded with green salt. 

The packing was done by foot...[The EE] had a respirator around [the EE’s] 

neck but was not using it... it was suspected that the ventilation was inadequate... 

the operator distributed additional green salt in the bomb by hand and visible 

clouds of dust could be seen around the shell top and in the working area.

It would not be difficult to create contamination in the work areas, considering that the beta 

exposure rates of some operations were in the 10–35 rep/hr (rep ~ rem) range, as stated in Table I 

of a WSS document (MCW 1959). A small amount of scale, cuttings, or dust from these 

operations would quickly contaminate the work area. Several quotes from interviews with 

former WSS workers (SC&A 2009, pages 71 and 72) illustrate that personnel contamination was 

common, and that there was a lack of egress monitoring: 

Contamination incidents occurred routinely. When there was a skin 

contamination incident, individuals just washed the material off. If a worker was 

contaminated with hot powder or acid, they would get a burn and have to go over 

to the dispensary to get it taken care of. The onus was put on the employee. 

Workers were not always successful at getting material in the cracks and crevices 
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off. They were not required to call a radiation monitor to take measurements. If 

they did, they would never get any production done. 

There were no routine contamination surveys of benches, floors, and other 

surfaces with smears. 

WS workers were not required to monitor themselves for radiation upon exit from 

a radiological area. When workers left the work area, to go to the break rooms 

or to lunch, to go home at night, or when they got contaminated, there was no 

station where they could monitor themselves. Their monitor was their film badge. 

Some workers used neutralizer to clean their hands when they exited the 

operations areas. 

Workers also indicated that they were allowed to smoke and drink liquids in the break rooms 

located inside the controlled areas without washing of hands, changing of clothes, or 

contamination checks. This practice could lead to undetected intakes in some individuals who 

were not monitored on a regular basis, especially those who were present in the work areas, but 

not considered as at-risk workers, such as supervisors, clerks, and security personnel. 

2.1 SUMMARY OF LACK OF CONTAMINATION/EGRESS MONITORING 

Workers were apparently allowed to leave the controlled areas and the WSS without 

confirmation that they were not contaminated. This could have spread contamination to noncontrolled areas at the site, creating chronic exposure (internal and external) to unmonitored 

workers, as well as leaving contamination on the workers that could lead to chronic beta 

exposure to the skin (especially in the folds of the skin) and internal exposure through ingestion 

and resuspension/inhalation. Personnel badges worn during working hours would not have 

picked up beta exposures from contamination on the skin that could have irradiated local skin 

areas for extended periods, especially in the folds of the skin around the ears, nose, neck, and 

arms. Additionally, because workers only periodically submitted urine samples, as described in 

ORAUT-TKBS-0028-5 (ORAUT 2005e), some of these individual internal intakes through this 

pathway could have been missed. Even with good dosimetry and records, there would be no 

records of these missed exposures for DR purposes. Contrary to the ER statement, neither the 

ER [nor ORAUT-TKBS-0028-6 (ORAUT 2005f)] specifically addressed the personnel 

contamination issue. This issue is applicable to numerous AEC/DOE sites and should be 

investigated in conjunction with methods recommended for other sites. 
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3.0 LACK OF INFORMATION FOR WORKERS DURING 1967 

It is not explicitly stated in the TBDs when DOE employees and DOE contractors were no longer 

working at the WSS after operations ceased in December of 1966. In Section 2.2.2.4 of 

ORAUT-TKBS-0028-2 (ORAUT 2005b), page 22, it is indicated that no AEC contractors were 

present until August 1975 (this is reiterated on page 30 of ORAUT-TKBS-0028-2); however, 

Section 6.13.2, page 12 of ORAUT-TKBS-0028-6 (ORAUT 2005f), states that: 

There is some anecdotal information to indicate that some former WSCP workers 

continued their employment during this period.

And 

“We do not feel such a contractor will need film badge services.” However, it is 

not clear if this statement refers to a continued presence by MCW staff.

This is referring to the 1967 to 1969 time period. 

The WSS TBDs do not state if DOE employees and contractors were present or involved during 

1967–1969, when the U.S. Army was attempting to decontaminate and renovate buildings 

located at the WS Chemical Plant. Sections 4.2.2.2 and 4.2.3.2 of ORAUT-TKBS-0028-4 

(ORAUT 2005d); Sections 5.3.2, 5.4.2, 5.5.2, 5.5.3, and 5.6.2 of ORAUT-TKBS-0028-5 

(ORAUT 2005e); and Sections 6.1.3.2 and 6.1.3.3 of ORAUT-TKBS-0028-6 (ORAUT 2005f) 

do not contain sufficient information for the dose reconstructor to be able to assess dose to 

claimants who may have worked for DOE or its contractors at the WSS during 1967. If DOE 

contract personnel were present at the WSS soon after the shutdown in December 1966, they 

could have been exposed to numerous radionuclides during decommissioning, cleaning out the 

equipment, and revamping the facility for a completely different use. Because uranium was 

viewed as a chemical rather than a radiological hazard at that time, sufficient controls and 

monitoring practices may have not have been in place. This was more likely to occur during the 

time period immediately following plant closure, because the MCW health and safety 

infrastructure at the WSS was no longer in place. Plant operating protocol would not have been 

enforced; buildings and equipment were considered surplus, and supplies/materials (including 

leftover radioactive material or contaminated material) would have been considered a nuisance 

and disposable. Working under these conditions could have created a mindset that radiological 

safety was not an issue (for both the contractor and the workers). This could have led to 

incidences of skin contamination, inhalation, and ingestion of radioactive materials (including 

uranium and thorium, as well as radionuclides contained in the raffinate concentrates and its 

scale/soil that had been resuspension) that were not monitored or recorded, or grossly 

underestimated. This potential lack of radiological control and monitoring for 1967 is illustrated 

by quotes from the WSS interviews (SC&A 2009, page 85): 

The period between 1967 and 1969 should especially be considered for dose 

reconstruction. One WS site expert has been in contact with a construction 

worker who was on site from 1967–1969. At the time, Thompson-Stearns-Rogers 

(TSR, Inc.), based in Denver, Colorado, was the prime contractor at the site. This 
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company was a merger of Stearns-Rogers (Denver) and Thompson (St. Louis). 

There were about 300 construction workers, hired out of the local labor market, 

working at the WS site during that period. 

The worker who provided information to the WS site expert worked in several 

former uranium production buildings. [The EE’s] job was to dig up the brick 

floor and replace it with a concrete floor. Part of the job involved washing down 

the area. The worker indicated that yellow cake would trickle down between the 

bricks and stay there. They had to beat the bricks up to get them out. In the 

process, they found chunks of yellow cake, which they handled with bare hands. 

The T-S-R workers put in a concrete floor with an extra layer of concrete. 

The workers digging up the bricks were dressed in regular clothes with boots. 

Initially, boots were left on site, but later, they could be taken home. In the same 

area, some people were dressed in protective gear with masks (i.e., moon suits). 

The worker thought these people were monitors; sometimes they would take [the 

EE] out of the building and tell [the EE] to stay out. The individuals in the “moon 

suits” and the employees working on the bricks were in the same area (breathing 

space). There was little communication between the workers and the monitors. 

The worker’s descriptions seemed to reflect that the operations were monitored, 

but the WS site expert did not know what company would have employed the 

monitors. 

The worker had worn a film badge on [the EE’s] chest, although the exposure 

source [the EE] encountered was on or under the floor. The worker did not recall 

any bioassay having been done for [the EE], and [the EE] did not receive a dose 

report based on [the EE’s] film badge reading. 

SC&A analyzed claims for workers that were employed at the WSS through 1967. It was found 

that some of the claimants’ DOE records listed film badge and/or bioassay results for the years 

prior to 1967, but none had any exposure records (film badge or bioassays) for 1967. NIOSH 

stated in the ER, page 50, that, “The CER database does not include any results for 1967, nor 

does NIOSH have hardcopy urinalysis data for this year.” 

3.1 SUMMARY OF LACK OF WORKERS’ INFORMATION FOR 1967 

The inclusion of the year 1967 in NIOSH’s ER extends the evaluation of the original SEC-00143 

petition for the WSS to an era unlike the production era of the original SEC petition, because the 

production facility was completely shut down during 1967. Examples have been given where 

workers were handing uranium by hand while digging up the floors to convert the building for a 

different use. There was no apparent local MCW and/or DOE administration oversight, health 

and safety organization, documentation, etc., to direct work practices, control exposures, and to 

keep records. Therefore, exposure records, bioassays, and environmental data do not appear to 

be sufficiently available for DR purposes for the year 1967. SC&A could not locate any 

monitoring data during the review of several claims that covered the 1967 period, and the ER 

does not include 1967 in any of the data provided. Neither production workers’ data nor 

environmental data from the production era (1957–1966) can be applied to the 1967 time period, 
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because the working conditions, exposure pathways, and potential intakes/external doses were 

completely different. SC&A recommends that the legal transfer date of the properties (including 

the WS plant, raffinate pits, and quarry) be determined and documented, and then the 1967 

exposures to AEC and/or AEC contractors be addressed. 
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4.0 INADEQUATE RADON/THORON DETERMINATION FOR 

MONITORED AND UNMONITORED WORKERS 

4.1 RADON 

Table 5-2 of ORAUT-TKBS-0028-5 (ORAUT 2005e) describes the potential radionuclide 

exposure in the different buildings of the WSS. Radon is listed as a source of exposure inside 

Buildings 101, 103, 105, 403 and 407. However, the recommended approach in ORAUT-TKBS0028-5 (page 37) to estimate radon doses is based on environmental radon concentrations 

calculated from uranium throughput for the areas within 100 meters of the assumed release 

point, the acid recovery plant stack [see ORAUT-TKBS-0028-4 (ORAUT 2005d), page 19 for 

details), but not from measurements. There were no radon measurements performed at the WSS 

during the operating period of 1957–1966, or during 1967, which is the period of the SEC. In 

ORAUT-TKBS-0028-4 (ORAUT 2005d), NIOSH used a 1985 reference (Meshkov 1986, page 

47 of the pdf file) that estimated the radon released by relating it to the uranium throughput per 

year. In that document, it was estimated that 5k–14.5k MT/year of uranium was processed at the 

WSS, that the yellowcake contained 70% uranium with 1% radium, that the radon was in 

equilibrium with the radium, and that all the radon escaped at the acid recovery plant. This 

resulted in a calculated release of 12–34 Ci/y of radon. 

ORAUT-TKBS-0028-4 (ORAUT 2005d), pages 17–19, then uses this 12–34 Ci/y release value, 

along with the simple dispersion model from NCRP Report 123 of 1996 (NCRP 1996), to derive 

an average concentration, adding in background radon (11 Bq/m3

), equal to 41–91 Bq/m3. 

According to page 17 of ORAUT-TKBS-0028-4 (ORAUT 2005d), the 91 Bq/m3

 concentration 

would lead to a maximum environmental outdoor dose of 0.087 WLM/y at an intake rate of 

2,400 m3

/y, using a radon daughter equilibrium factor of 0.3. 

The ER (NIOSH 2010, page 28) used a maximum concentration value of 80 Bq/m3 (which is 

91 Bq/m3

 with the background radon value of 11 Bq/m3 removed) to derive a maximum 

environmental outdoor dose of 0.076 WLM/y. On page 57 of the ER, NIOSH used a radon 

daughter equilibrium factor of 0.5 for indoor calculations and derived a value of 0.13 WLM/y 

(apparently the value of 1.3 should read 0.13 on page 57 of the ER when considering the 

surrounding contents). 

The NIOSH ER (NIOSH 2010, page 57), ORAUT-TKBS-0028-4 (ORAUT 2005d, page 20), and 

ORAUT-TKBS-0028-5 (ORAUT 2005e, page 37) recommend the use of an indoor radondaughter equilibrium factor of 0.5, compared to 0.3 used for outdoors. ORAUT-TKBS-0028-5, 

(ORAUT 2005e) page 37, states that only a small fraction was released into the room during 

processing, and that the main concentration in the indoor work areas would be from that 

drawn back into the room from the environment; hence, the indoor concentration would be 

equal to the calculated environmental concentration. Using this approach requires that several 

assumptions be made, which results in large uncertainties in an already calculated (not measured) 

value; especially for workers located in indoor workplaces. 

The data from MCW St. Louis Downtown Site in ORAUT-TKBS-0005 (ORAUT 2005g) have 

shown that there is no correlation between outdoor and indoor radon concentration. In Table 24 
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of ORAUT-TKBS-0005 (ORAUT 2005g, page 209), indoor and outdoor radon measurements 

are listed. Indoor radon measurements in the Scalehouse and outdoor radon measurements in 

Scalehouse exhaust are reproduced in Table 2 for 1948. The average values for indoor 

measurements are approximately 4 times greater than the average values for outdoor 

measurements. The same pattern is observed in the indoor and outdoor measurements presented 

in other tables in ORAUT-TKBS-0005 (ORAUT 2005g). 

Table 1. Comparison of Indoor and Outdoor Radon Measurements for the Scalehouse 

(Data from Table 24 of ORAUT-TKBS-0005) 

Measured radon concentrations for 1948 in units of 1 × 10-10 Ci/L Workplaces No. of samples Min Med/Mean Max GSD 

Indoor areas 

Scalehouse 21 0.00 4.05 33 

Scalehouse 193 0.03 2.02 32.8 

Scalehouse Sample room 6 0.22 4.10 19 

Scalehouse Sample room 68 0.03 2.84 25 

Average = 3.25 

Yards and other outdoor areas

Scalehouse intake/exhaust 3 0.12 2.06 

Scalehouse exhaust 18 0.13 3.08 

Scalehouse exhaust 1 0.93 

Scalehouse exhaust 24 0 2.2 49 

Average = 0.85 

Ratio of Indoor/Outdoor = 3.25/0.85 ~ 4. 

Although not specific to the WSS, this example shows that the assumption of equal radon 

concentrations in the indoor areas compared to the outdoor areas, as recommended in NIOSH’s 

ER and ORAUT-TKBS-0028-5 (ORAUT 2005e), is not supported by actual measurements. 

4.2 THORON 

NIOSH addressed thoron (a decay product of thorium with a 55-sec half-life) on pages 28 and 57 

of the ER and concludes the following: 

Given the specific activity of thoron in thorium feed materials, and assuming the 

feed materials were received with at least a one-year delay since processing, it is 

possible to calculate the amount of thoron in process per day (approximately 

0.3 Ci thoron) during the period of the maximum production rate. By assuming a 

conservative equilibrium factor for a plant configuration with large buildings and 

engineered ventilation (0.02), it is possible to determine the concentration of 

thoron and its daughters to achieve 1 WL [working level]. The release fraction 

(RF) can be calculated by measuring the particulate thorium in the working 

environment of the process equipment, compared to the inventory amounts in 

process. The thoron releases are expected to be less than the particulate 

materials, since the gaseous state will be more easily captured by the ventilation 
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systems. Maximizing assumptions can be applied on a case-by-case basis to 

occupancy factors, release fractions, and diffusion rates. 

4.3 SUMMARY OF INADEQUATE RADON AND THORON DETERMINATION 

4.3.1 Radon 

The outdoor environmental radon concentration was calculated, not measured, and was based on 

a non-documented point of release. Additionally, ground releases cannot be reliably modeled by 

a simple dispersion model, especially for indoor exposures. The assumption of equal radon 

concentrations in the indoor areas compared to the outdoor areas, as recommended in NIOSH’s 

ER and ORAUT-TKBS-0028-5 (ORAUT 2005e), is not supported by actual measurements 

performed at the Destrahan Street site. These are potential SEC issues for both non-production 

and production workers, unless NIOSH can propose a more reliable and claimant-favorable 

approach to assess the radon exposure, especially for indoor operations areas for the WSS. 

4.3.2 Thoron 

There were no specific measurements for thoron decay products made at the WSS. Therefore, 

NIOSH recommends a modeling method based on certain assumptions. However, this method is 

not detailed concerning the procedure to be used and how the values of the variables are tied to 

the WSS during the operational period. Additionally, there are no provisions for the intake of 

thoron decay products if thorium was stored onsite before 1963, from the raffinate pits, or from 

the disposal of thorium in the quarry, since the recommended method would only apply to 

processed thorium. NIOSH states on page 67 of the ER that there are DWA concentration air 

monitoring data from the years 1957 through 1966, and that the data (1957–1966) encompass the 

span of thorium processing at the site. However, the thorium data on page 41 of the ER only 

cover the period 1963–1966. 
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5.0 INADEQUATE RECOMMENDATION FOR ASSIGNING 

RECYCLED URANIUM DOSE 

According to the TBD, recycled uranium (RU) was contained in some of the uranium materials 

received at the WSS starting around 1961. 

 

ORAUT-TKBS-0028-5, page 15, addresses RU at the WSS as follows: 

5.2.4 Recycled Uranium 

The extent of the processing of recycled uranium at WSP is not well known 

(ORAU 2005b, Section 2.2.3) [ORAUT 2005b]. The DR should make the 

claimant-favorable assumption that all of the uranium processed at WSP after 

1961 was recycled uranium. This assumption is consistent with that in Ohio Field 

Office Recycled Uranium Recovery Report (DOE 2000b) [DOE 2000], which 

assumed that all uranium receipts at WSP after 1961 were recycled uranium in 

lieu of better information. [Emphasis added.]

Contaminant radionuclides in recycled uranium that could be dosimetrically 

significant are plutonium (assume 239Pu), neptunium (237Np), and technetium 

(

99Tc). Site-specific data for the mass fractions of these contaminants are not 

available. The DR should consider the factors in Table 5-11 of Technical Basis 

Document for the Fernald Environmental Management Project – Occupational 

Internal Dose (ORAU 2004a) [ORAUT 2004]. These factors, when multiplied by 

the assessed uranium gram-value intake, result in the activity per gram of 

uranium of the contaminants at the levels of 100 ppb 239Pu, 3,500 ppb 237Np, and 

9,000 ppb 99Tc. [Emphasis added.]

The section in Fernald that ORAUT-TKBS-0028-5 is referring to reads as follows: 

Though the long-term average RU contaminant levels in the plant are below 

10 ppb U for plutonium, there are places and materials in the plant that could 

have provided RU contaminants above these average values. Based upon the 

preceding facts and conditions, the most technically defensible and claimantfavorable approach to assure that missed internal dose from unmonitored and/or 

undetected TRU activities (that were present throughout all of the Fernald plants 

from 1961) were accounted for is to determine the uranium intake and add a ratio 

of TRU to that intake. Therefore, it would be reasonable and claimant favorable 

to add 100 ppb U for 239Pu, 3500 ppb U for 237Np, and 9,000 ppb U for 99Tc to the 

calculated uranium gram value intakes calculated by the dose reconstruction staff 

from uranium after 1961. Table 5-11 lists conversion factors for this approach: 

[Emphasis added.] 
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 Table 5-11. PPB conversion factors. 

RU 

Contaminant 

ppb U × (value) 

= pCi gm-1

ppb U × (value) 

= Bq gm-1

ppb U × (value) 

= dpm gm-1

Pu-239 62.89 2.327 139.6 

Np-237 0.714 0.0264 1.59 

Tc-99 17.15 0.6346 38.07 

The chemical forms of the RU contaminants are not known, although it is 

apparent from the chemical processes to which the materials were subjected 

during uranium processing, a variety of forms would be expected. Hence the dose 

reconstructor should assume the most claimant-favorable solubility type for the 

target organ. 

And on pages 25–26, the ER states the following: 

5.2.1.3 Recycled Uranium 

In 1999, DOE initiated the complex-wide Recycled Uranium Mass Balance 

Project, which identified the Weldon Spring Plant as a site that likely received 

recycled uranium in relatively small quantities of materials after 1961 (ORAUTTKBS-0028-2). The significance of these shipments of recycled uranium is that 

this material contained trace amounts of residual transuranic elements (including 

plutonium and neptunium), fission products (such as technetium), and reactorproduced uranium isotopes (such as uranium-236) (DOE, 2000). [Emphasis 

added.]

Contaminant radionuclides in recycled uranium that could be dosimetrically 

significant are plutonium (assume plutonium-239), neptunium (neptunium-237), 

and technetium (technetium-99). Site records do not include the level of detail 

needed for an accurate estimate of the amount of recycled material received and 

processed at the Weldon Spring Plant site. However, greater than 99% (by 

weight) of the slightly enriched uranium received at the Weldon Spring Plant site 

was from Fernald (DOE, 2000, p. 1,130). For the purpose of this evaluation, the 

uranium source term is considered to be: 

 Prior to 1961, natural uranium 

 1961–1967, recycled uranium. 

For the periods that included recycled uranium, Table 5-6 contains maximum 

values for the recycled uranium contaminants as a fraction of uranium intake 

based on material that is likely to have been received by Weldon Spring (DOE, 

2000, p. 1,140). 
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Table 5-6: Maximum Recycled Uranium Contaminant Levels 

Bounding Valuea

Contaminant 

Average 

Concentration 

(ppbU) 

Observed Range 

(ppbU) ppbU pCi/μgU pCi/pCiU 

Plutonium 2.9 0.60–15 6.3 3.9E-04 5.7E-04 

Neptunium-237 390 5–3,200 1,800 1.3E-03 1.9E-03 

Technetium-99 8,600 800–19,000 21,000 0.36 0.53 

Note: 

a

 Calculated as the 95th percentile of an unblended uranium trioxide PUREX source, assuming a lognormal distribution. 

This provides the highest values for the two subgroups of recycled uranium likely received by Weldon Spring (DOE 2000).

And on page 65 of the ER, it states the following: 

7.4.3 Recycled Uranium 

SEC-00143: The petitioner is concerned that the Weldon Spring Plant site was 

identified as a site that likely received recycled uranium in relatively small 

quantities of materials after 1961, and site records do not include the level of 

detail needed for accurate estimates of the amount of recycled material received 

and processed at Weldon Spring Plant. It is known that the plant received 

shipments from other DOE sites that processed and shipped recycled uranium, in 

fiscal years 1962 through 1967, but amounts of recycled uranium versus natural 

uranium are not known. 

 

Response: NIOSH investigated the receipts and processing of recycled uranium 

at the Weldon Spring site and acknowledges that limited quantities of recycled 

uranium were received at Weldon Spring for processing. The fact that the 

quantities of recycled uranium are unknown led DOE to assume, as a worst case, 

that all uranium received after 1962 was recycled uranium. DOE acknowledges 

that this assumption leads to the worst-case quantities of transuranic elements. 

These quantities do not represent what was actually processed, and in fact, DOE 

estimates these quantities to be significantly less (0.0 gm [grams] of plutonium239, 12.3 to 15.3 grams of neptunium-237, and 4.9 to 6.1 grams of technetium-99, 

as compared to the worst case 2.4 grams, 330 grams, and 7,200 grams of 

plutonium, neptunium, and technetium respectively). For the purpose of defining 

the ability to bound dose for the evaluated class in this report, the maximum 

quantities have been considered as the source term for this evaluation. 

[Emphasis added.] 

SC&A did not locate a DR Guide for the WSS. The DR Guide for the Fernald site, page 1, 

(ORAUT 2007) only contains the following statement concerning RU: 

a. Recycled uranium was introduced to FMPC in 1961. 

Radionuclide Scenario 1 Scenario 2 Scenario 3 

U-234 F M S 

Pu-239 M M S 

Np-237 M M M 

Tc-99 F M M 
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5.1 SUMMARY OF INADEQUATE RECYCLED URANIUM DOSE ASSIGNMENT 

RECOMMENDATIONS 

SC&A found the year that the dose reconstructor is to start assigning all RU doses from the 

uranium analysis is not consistent within the documents quoted above. If materials potentially 

containing RU started to be processed in 1961 at the WSS, then the dates should be consistently 

stated as “prior to 1961” and “1961 and after,” not “after 1961” or “after 1962.” Additionally, it 

has not been verified that the WSS did not receive RU before 1961.

SC&A found that ORAUT-TKBS-0028-5, page 15, recommends that 100 ppb Pu-239, 3,500 ppb 

Np-237, and 9,000 ppb Tc-99 be added to the intake, based on the uranium intake value. SC&A 

deciphered the contents of Fernald ORAUT-TKBS-0017-5, Table 5-11, conversion factors as 

follows: 

#pCi Pu-239 = (100 ppb-Pu/U) × (62.89 pCi-Pu/gm-U per 1ppb-Pu/U) × (#gm-U in bioassay) 

Where: 1ppb-Pu/U = (1E-9 gm-Pu/gm-U) × (6.21E-2 Ci-Pu/gm-Pu) × (1E12 pCi/Ci) 

~ 62.89 pCi-Pu/gm-U 

 6.21E-2 Ci-Pu/gm-Pu is the specific activity of Pu-239. 

This is not made very clear in ORAUT-TKBS-0028-5 (ORAUT 2005e), page 15, or ORAUTTKBS-0017-5 (ORAUT 2004), page 17, but is applicable if used correctly. The same analysis 

applies to Np-257 and Tc-99. SC&A’s review of WSS claims indicates that this method was 

correctly applied in one of the full DR best-estimate cases SC&A analyzed. However, in several 

of the DR cases, where the probability of causation was <50% and a full DR should have been 

performed and the EE worked during the 1961–1966 time period, no internal intakes from RU 

were assigned. This is technically a DR issue and not an SEC issue, but the oversight during DR 

may have resulted from lack of clarity in ORAUT-TKBS-0028-5 (ORAUT 2005e). 

Additionally, Table 5-6, page 27, of the NIOSH ER lists values not found elsewhere in the 

documents quoted above; hence, there does not appear to be a consistency between the ER and 

the TBDs. It is not obvious how the values listed in Table 5-6 of the ER were derived from DOE 

2000, why they are lower than the recommended values found in the WSS TBD, and how they 

are to be applied in the DR process. The reference provided in the ER was DOE 2000, page 

1140; however, there is no indication in the ER how the data in Table 1 on page 1140 and the 

following pages, generated the values listed in Table 5-6 of the ER. SC&A found that a 1964 

WSS document (MCW 1964) provided some qualitative analyses of alpha and gamma activities 

and energy spectra, and comparative external exposure rates of two feed materials sampled in 

1964. However, this does not provide quantitative values of Pu-239, Np-237, and Tc-99 by 

which to derive ppb-U values to compare to the Fernald values, or the values recommended in 

the ER. 

Even if the greater concentration values of 100 ppb Pu-239, 3,500 ppb Np-237, and 9,000 ppb 

Tc-99 are used, it has not been documented that these values are necessarily correct or bounding. 

SC&A reviewed the source of these concentration values, which is a document entitled, DOE 

Ohio Field Office Recycled Uranium Project Report (DOE 2000), as referenced in the ER. 
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However, this document does not provide defined sources for its recommended values of the 

radionuclide concentrations; therefore, these concentration values appear to be estimates or 

assumptions, rather than measured values. Because both the WSS TBD and the ER base the RU 

composition and throughput at the WSS on Fernald RU data, then the Fernald issues are relevant 

to the WSS issues and, as SC&A has pointed out in their review of the Fernald SEC (SC&A 

2007), there are contradictions within the Fernald TBDs, the DOE 2000 document, and the DOE 

2003 document; hence, “it is likely that the DOE 2000, which is the basis for the data on RU, is 

incorrect even for the basic value relating to uranium receipts at Fernald” (SC&A 2007, page 

35). 
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6.0 NEUTRON DOSIMETRY RECORDS NOT AVAILABLE 

NIOSH states the following on page 33 of the ER: 

... those employees that processed the slightly-enriched uranium were assigned 

special neutron dosimeter badges to be worn in conjunction with their regular 

film badge dosimeters. Neutron dose results for these Weldon Spring employees 

have not been located, plausibly because there was no measured neutron dose. 

NIOSH concludes on page 61 that it has considered the potential source of neutrons resulting 

from alpha-neutron reactions and determined that in the cases where NIOSH needs to apply 

unmonitored neutron dose for members of the class, it can apply the methods approved in 

ORAUT-OTIB-0024 (ORAUT 2005h) to support bounding the neutron dose. The applicability 

of this method will be assessed on a case-by-case basis for individual DRs. Additionally, it 

states that in the absence of measured dosimeter doses, the primary method for assigning 

potential neutron dose is in the determination of missed neutron dose, as described in the NIOSH 

document, External Dose Reconstruction Implementation Guideline (OCAS-IG-001). 

6.1 SUMMARY OF NEUTRON DOSIMETRY RECORDS NOT AVAILABLE 

In the WSS profile review (SC&A 2009), SC&A did not agree with the recommended method in 

ORAUT-TKBS-0028-6 (ORAUT 2005f) concerning using a one-time measurement at Fernald to 

assign neutron doses at the WSS. Additionally, SC&A does not find that there is sufficient 

information available for WSS workers to assign neutron doses based on the worker’s 

location/job function, and/or that assigning neutron dose based on missed dose is technically 

correct, because missed dose can only be assigned if the badge reading is available and the 

recorded reading was less than 1⁄2 the lower limits of detection. This is a situation where 

exposure could have occurred, but no recorded dose data are available. 
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7.0 QUARRY AND RAFFINATE PITS EXPOSURES 

INADEQUATELY ADDRESSED 

NIOSH states on page 28 of the ER that radon measurements in the quarry area in the late 1970s 

and early 1980s (before remediation) averaged 0.65 ± 0.41 pCi/L, indicating that the quarry was 

not a major source of radon, and that as in the case of the raffinate pits, this value would be 

limiting for the operational period. NIOSH also states the following on page 28 of the ER: 

Prior to 1963, the quarry only contained drummed thorium wastes that were 

likely submerged and not a significant source of radon. In 1963 and 1964, an 

estimated 38,000 m3 of uranium- and radium-contaminated rubble, equipment, 

and soil were placed in the quarry following demolition of the Destrehan Street 

site, with a majority of this waste not submerged, providing a potential source of 

radon exposure (Unknown, 1967; ORAUT-TKBS-0028-4). Measurements in the 

quarry area in the late 1970s and early 1980s (before remediation) averaged 0.65 

± 0.41 pCi/L, indicating that the quarry was not a major source of radon 

(Meshkov, 1986, p. 101). As in the case of the raffinate pits, this value would be 

limiting for the operational period. 

On page 56 of the ER, NIOSH states the following: 

Measurements of the activity concentrations in Raffinate Pits 1, 2, and 3 can be 

used to determine the relationship between thorium-230 and other impurities 

during the initial uranium processing in Building 101 before any separations 

occurred. The shorter-lived decay products for which no raffinate measurements 

were made (e.g., lead-210 and polonium-210) can be assumed to be present at the 

same activity as their radium-226 parent in the mill concentrate feeds. The other 

uranium streams (e.g., recycled uranium) had been previously processed and 

contained essentially no thorium. Table 7-4 gives the results of a statistical 

analysis of raffinate pit measurements. The data were taken from the 1989 Waste 

Assessment Radiological Characterization of the Weldon Spring Site Raffinate 

Pits (MK-Ferguson, 1989). 

NIOSH assumes that measurements made in later years would bound the operational years, 

because the ingrowth of decay products would be greater as time progressed. 

7.1 SUMMARY OF QUARRY AND RAFFINATE PITS EXPOSURE ISSUES 

SC&A agrees that the ingrowth of decay products would increase as a function of time. 

However, the exposure conditions were not necessarily the same during the operational phase as 

during the later years at the WSS. The quarry and raffinate pits were actively being used during 

the operational period, with radioactive materials being dumped into them, but were idle during 

the following years when the measurements of constituents, air samples, and external doses were 

performed. The difference in physical and chemical compositions and usage negates the 

extrapolation of the later measurements to the operational era without at least some minimal 

comparison measurements to validate such extrapolations. For example, how do the values 
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obtained in later years compare with those found in the Mason document of 1958 (Mason 1958)? 

While the intakes and external exposures for unmonitored workers may be bound by the data 

from monitored workers in the plant, workers exposed to the raffinate pits and quarry have no 

counterpart for dose assignment if they were not monitored for external exposures or bioassayed 

for the specific radionuclides present in these locations. 

 
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8.0 INSUFFICIENT INVESTIGATION & DOCUMENTATION OF 

OFF-NORMAL SITUATIONS AND ACCIDENTS/INCIDENTS 

NIOSH states on page 33 of the ER that the Health and Safety Division maintained annual 

logbooks of forms and memos for employees with high urinary uranium concentrations. 

Investigation reports were also included in the logs (for Action Level 2 exposures and above). 

Descriptions of the data forms in Table 5-10 of the ER are included to demonstrate Weldon 

Spring’s management of and response to high bioassay results. 

And on page 66 of the ER, NIOSH states the following: 

NIOSH has conducted a thorough investigation into documentation that gives no 

indication of significant accidents or incidents at the facility. While several 

events were identified through document searches and interviews with former 

workers, there were no indications of events that could have resulted in 

exceptionally high personnel exposures or exposures that are not already 

accounted for within the data in the available records.

8.1 SUMMARY OF INSUFFICIENT INVESTIGATION 

The issue to be addressed is not if identified high levels of exposures were investigated; 

normally these would have been investigated under the direction of the AEC. Instead, it is the 

off-normal situations and accidents/incidents that were not sufficiently identified at the time as 

radiological events. 

Off-normal Situations – An area not addressed by either the ER or the TBDs are exposure 

potentials not normally encountered in routine operations at the plant. For example, WSS 

workers transported material and spent some time at the MCW St. Louis site, the quarry where 

Destrehan Street material was dumped, and the airport site; were these workers appropriately 

monitored? Another example is the workers that transported and handled the material sent to the 

Bevatron; were they appropriately monitored? How were exposures from episodical plant 

releases accounted for? 

Accidents/Incidents – During onsite interviews with former WSS workers, the subject of 

accidents/incidents was often brought up, with the concern that MCW did not identify and 

document radiological events sufficiently, either through lack of knowledge of the radiological 

hazards or as a manner of policy at that time. SC&A’s preliminary investigation of several cases 

indicates that the accidents described by former workers were not evident or were not recorded 

sufficiently in the workers’ DOE files. For example, a serious furnace accident occurred in 

1960; however, the only mention of it in the worker’s DOE records was a couple of brief 

sentences describing the medical aspect of the worker’s complaints; no investigation into the 

radiological aspect of the accident was evident. There was no other documentation of the 

accident in the worker’s files that SC&A could locate. Another serious accident apparently 

occurred in 1961; the only reference in the worker’s DOE file was an entry in the “PERSONAL 

MONITORING SUMMARY RECORD,” which stated that “Data included in Feb. Accident 

File.” There was no other record of it in the worker’s DOE records. Fortunately, this accident 
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was written up in a MCW report and the dose reconstructor evaluated the dose received from the 

accident during the DR process. However, this may not always be the case. 
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NOTICE: This report has been reviewed for Privacy Act information and has been cleared for distribution. 

However, this report is pre-decisional and has not been reviewed by the Advisory Board on Radiation and Worker 

Health for factual accuracy or applicability within the requirements of 42 CFR 82. 

9.0 GEOMETRY AND EXTREMITY ISSUES NOT ADDRESSED 

NIOSH states in the ER (page 67) that the petitioner’s concerns of a lack of a documented 

badging policy with geometry correction factors were among several broad statements that were 

the basis for qualifying the petition. NIOSH stated that these concerns resulted in the evaluation 

of the petition for the Weldon Spring Plant, and that NIOSH’s response to these concerns were 

encompassed in the ER. However, SC&A could not find that the ER or ORAUT-TKBS-0028-6 

(ORAUT 2005f) addressed these issues. 

9.1 SUMMARY OF GEOMETRY AND EXTREMITY ISSUES 

The problems associated with handling uranium material [contact work as stated on page 20 of 

ORAUT-TKBS-0028-6 (ORAUT 2005f)] close to the body/hands and having the dosimeter 

badge located on the chest area was not addressed in the ER, ORAUT-TKBS-0028-6 (ORAUT 

2005f), or other WSS documents. A film badge does not register the same dose as the worker’s 

tissue/organs are receiving from the beta and low-energy photons when handling, machining, 

scooping, etc., uranium-containing materials. For example, a 1958 (MCW 1959) office memo 

illustrates the fact that the shielding on a lathe greatly affects the beta dose measured; i.e., 

decreases it from an average of 122 mrep/hr to 0 and Table I of that document lists non-trivial 

beta doses as high as 10,000 to 35,000 mrep/hr (mrep ~ mrem). Therefore, any material/distance 

between the beta source and the badge on the worker’s chest that is not between the beta source 

and the worker’s trunk area will cause an under-response in the recorded dose. 

Compounding the geometry issue is the fact that there does not appear to have been any 

extremity monitoring at the WSS, which, as indicated above, was needed. Contrary to the ER 

statement, neither the ER [nor ORAUT-TKBS-0028-6 (ORAUT 2005f)] addressed the geometry 

or extremity issues. This issue has been encountered at other AEC/DOE sites and should be 

investigated in conjunction with methods recommended for other sites.
Effective Date: 

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NOTICE: This report has been reviewed for Privacy Act information and has been cleared for distribution. 

However, this report is pre-decisional and has not been reviewed by the Advisory Board on Radiation and Worker 

Health for factual accuracy or applicability within the requirements of 42 CFR 82. 

REFERENCES 

42 CFR 82, 2002. Methods for Radiation Dose Reconstruction Under the Energy Employees 

Occupational Illness Compensation Program Act of 2000, Code of Federal Regulations, May 2, 

2002. 

Adams, D. and Strom, D. 2008. Uncertainty and Variability in Historical Time-Weighted 

Averaged Exposure Data, Heath Physics, Vol. 94, No. 2, p.145-160. 

Battelle 2006. Site Profiles for Atomic Weapons Employers that Refined Uranium and Thorium, 

Battelle-TBD-6001, Rev. FO; Battelle Team Dose Reconstruction Project for NIOSH; December 

13, 2006; SRDB Ref ID: 30673. 

Battelle 2007. Default Assumptions and Methods for Atomic Weapons Employer Dose 

Reconstruction, Battelle-TIB-5000, Rev. 00; Battelle Team Dose Reconstruction Project for 

NIOSH; April 2, 2007; SRDB Ref ID: 32016 

Burr, R., 1960. MCW (Mallinckrodt Chemical Works) office letter, Uranium Dust Exposure of 

Pilot Plant Operator, Health and Safety Department, Uranium Division, Weldon Spring, 

Missouri, June 13, 1960. Ref ID: 15001. 

DOE 2000. DOE Ohio Field Office Recycled Uranium Project Report, Final; Department of 

Energy (DOE); May 15, 2000; SRDB Ref ID: 3644. 

DOE 2003. Recycled Uranium: United States Production Enrichment and Utilization, 

Department of Energy (DOE); DOE/SO-0003, May 2003. 

Mason, M. 1958. Letter from M. Mason of MCW to S. Anonsen. Weldon Spring Raffinate 

Radioactivity Survey. December 9, 1958. Ref ID: 15016. 

MCW (Mallinckrodt Chemical Works) 1959. Shielded and Unshielded Average Time Required 

for Lathe Operations and Percent of Working Day To Establish Maximum Available Exposures 

At Operator’s Position, Health and Safety Department, Uranium Division, Weldon Spring, 

Missouri, (no author or date, date of 1959 taken from graph). Ref ID: 14938. 

MCW (Mallinckrodt Chemical Works) 1964. Health Physics Consideration for Recycled 

Materials. November 5, 1964. Ref ID: 11818, pdf pages 3–6. 

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and Safety Department, Uranium Division, Weldon Spring, Missouri, Revised 1965. Ref ID: 

14998. 

Meshkov, N., P. Benioff, J. Wang, and Y. Yuan, 1986. Weldon Spring Historical Dose Estimate. 

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Effective Date: 

October 28, 2010 

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0 – Draft 

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NOTICE: This report has been reviewed for Privacy Act information and has been cleared for distribution. 

However, this report is pre-decisional and has not been reviewed by the Advisory Board on Radiation and Worker 

Health for factual accuracy or applicability within the requirements of 42 CFR 82. 

MK-Ferguson, 1989. Waste Assessment Radiological Characterization of the Weldon Spring 

Site Raffinate Pits, Rev. 0, DOE/OR/21548-062; MK-Ferguson Company and Jacobs 

Engineering Group; August 1989; SRDB Ref ID: 12541. 

NCRP (National Council on Radiation Protection and Measurements) 1996. Screening Models 

for Releases of Radionuclides to Atmosphere, Surface Water and Ground, Report 123, Vol. 1, 

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NIOSH 2009a. White Paper on the Use of FMPC DWE Reports for Estimation of Chronic Daily 

Intake Rate, Rev. 02. R. Morris. National Institute for Occupational Safety and Health, Office 

of Compensation Analysis and Support, Cincinnati, Ohio. February 26, 2009.

NIOSH 2009b. SEC-00143 – Petition: All employees of the Department of Energy, Department 

of Energy contractors, or subcontractors who worked in any area at the Weldon Spring Plant in 

Weldon Spring, Missouri, during the applicable covered operational period from January 1, 

1957 through December 31, 1966. National Institute for Occupational Safety and Health, Office 

of Compensation Analysis and Support, Cincinnati, Ohio. September 11, 2009. 

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Ohio. April 16, 2010. 

OCAS-IG-001. 2006. External Dose Reconstruction Implementation Guideline, Rev. 2, 

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Support, Cincinnati, Ohio. August 25, 2006. 

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– Occupational Internal Dose, ORAUT-TKBS-0017-5, Rev. 00, Oak Ridge Associated 

Universities Team, Cincinnati, Ohio. May 2004. 

ORAUT 2005a. Weldon Spring Plant – Introduction, ORAUT-TKBS-0028-1, C. Little and R. 

Meyer, Rev. 00, Oak Ridge Associated Universities Team, Cincinnati, Ohio. June 28, 2005. 

ORAUT 2005b. Weldon Spring Plant – Site Description, ORAUT-TKBS-0028-2, C. Little and 

L. McDowell-Boyer, Rev. 00, Oak Ridge Associated Universities Team, Cincinnati, Ohio. June 

24, 2005. 

ORAUT 2005c. Weldon Spring Plant – Occupational Medical Dose, ORAUT-TKBS-0028-3, T. 

Lopez and J. Furman, Rev. 00, Oak Ridge Associated Universities Team, Cincinnati, Ohio. June 

24, 2005. 

ORAUT 2005d. Weldon Spring Plant – Occupational Environmental Dose, ORAUT-TKBS0028-4, L. McDowell-Boyer and C. Little, Rev. 00, Oak Ridge Associated Universities Team, 

Cincinnati, Ohio. June 28, 2005. 
Effective Date: 

October 28, 2010 

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0 – Draft 

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 This report has been reviewed for Privacy Act information and has been cleared for distribution. 

However, this report is pre-decisional and has not been reviewed by the Advisory Board on Radiation and Worker 

Health for factual accuracy or applicability within the requirements of 42 CFR 82. 

NOTICE:

ORAUT 2005e. Weldon Spring Plant – Occupational Internal Dose, ORAUT-TKBS-0028-5, 

Janet A. Johnson and Roger B. Falk, Rev. 00. Oak Ridge Associated Universities Team, 

Cincinnati, Ohio. June 28, 2005. 

ORAUT 2005f. Weldon Spring Plant – Occupational External Dosimetry, ORAUT-TKBS0028-6, J. Langsted and C. Little, Rev. 00. Oak Ridge Associated Universities Team, Cincinnati, 

Ohio. June 24, 2005. 

ORAUT 2005g. Basis for Development of an Exposure Matrix for the Mallinckrodt Chemical 

Company St. Louis Downtown Site and the St Louis Airport Site, St. Louis, Missouri, Period of 

Operation: 1942–1958, ORAUT-TKBS-0005, Rev. 01. Oak Ridge Associated Universities 

Team, Cincinnati, Ohio. March 2005. 

ORAUT 2005h. Estimation of Neutron Dose Rates from Alpha-Neutron Reactions in Uranium 

and Thorium Compounds, ORAUT-OTIB-0024, Rev. 00. Oak Ridge Associated Universities 

(ORAU) Team Dose Reconstruction Project for NIOSH; April 7, 2005; SRDB Ref ID: 19445. 

ORAUT 2007. Internal dose notes for FMPC cases (3/6/07). Oak Ridge Associated 

Universities Team, Cincinnati, Ohio. March 3, 2007. 

SC&A 2005. Supplemental Review of the Mallinckrodt Site Profile, Rev. 1. SCA-TR-TASK5-

0056, SC&A, Inc., McLean, Virginia, and Saliant, Inc., Jefferson, Maryland. April 18, 2005.

SC&A 2007. Review of the Feed Materials Production Center (FMPC) Special Exposure 

Cohort (SEC) Petition-00046 and the NIOSH SEC Petition Evaluation Report, Rev. 0. SCA-TRTASK5-0056, SC&A, Inc., Vienna, Virginia, and Saliant, Inc., Jefferson, Maryland. May 31, 

2007. 

SC&A 2009. Review of the NIOSH Site Profile for the Weldon Spring Site in Weldon Spring, 

Missouri, Rev. 0. SCA-TR-TASK1-0028, SC&A, Inc., Vienna, Virginia, and Saliant, Inc., 

Jefferson, Maryland. February 10, 2009. 

Unknown, 1967, Weldon Spring Raffinate Pits and Quarry Task Force Report; Unknown author; 

June 1, 1967; SRDB Ref ID: 3645, pp. 50–66.