Draft 

ADVISORY BOARD ON 

RADIATION AND WORKER HEALTH 

National Institute for Occupational Safety and Health 

Review of the NIOSH Site Profile for the Weldon Spring Site 

in Weldon Spring, Missouri 

Contract No. 200-2009-28555 

Task Order No. 1 

SCA-TR-TASK1-0028

Prepared by 

S. Cohen & Associates 

1608 Spring Hill Road, Suite 400 

Vienna, Virginia 22182 

Saliant, Inc. 

5579 Catholic Church Road 

Jefferson, Maryland 21755

February 2009 

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 predecisional 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-TR-TASK1-0028 

Effective Date: 

Draft – February 10, 2009 

S. Cohen & Associates: 

Technical Support for the Advisory Board on 

Radiation & Worker Health Review of 

NIOSH Dose Reconstruction Program Revision No. 

0 – Draft 

REVIEW OF THE NIOSH SITE PROFILE 

FOR THE WELDON SPRING SITE IN 

WELDON SPRING, MISSOURI 

Page 1 of 61 

Task Manager: 

________________________ Date: ___________ 

Joseph Fitzgerald 

Project Manager: 

________________________ Date: ___________ 

John Mauro 

Supersedes: 

N/A 
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TABLE OF CONTENTS 

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

1.0 Executive Summary.............................................................................................................7 

1.1 Summary of Primary Findings...............................................................................10 

1.1.1 Findings Common to Several TBDs..........................................................10 

1.1.2 Findings Specific to a TBD........................................................................11 

1.2 Summary of Strengths............................................................................................14 

1.3 Opportunities for Improvement .............................................................................15 

1.3.1 Observations – General..............................................................................15 

1.3.2 Observations – Occupational Medical Dose..............................................15 

1.3.3 Observations – Environmental Dose .........................................................15 

1.3.4 Observations – Internal Dose.....................................................................16 

1.3.5 Observations – External Dose....................................................................17 

2.0 Scope and Introduction ......................................................................................................18 

2.1 Review Scope.........................................................................................................18 

2.2 Asseessment Criteria and Methods........................................................................19 

2.2.1 Objective 1: Completeness of Data Sources.............................................20 

2.2.2 Objective 2: Technical Accuracy..............................................................20 

2.2.3 Objective 3: Adequacy of Data.................................................................20 

2.2.4 Objective 4: Consistency among Site Profiles..........................................20 

2.2.5 Objective 5: Regulatory Compliance........................................................20 

2.3 Dose Reconstruction under EEIOCPA ..................................................................21 

2.4 Report Organization...............................................................................................23 

3.0 Vertical Issues....................................................................................................................24 

3.1 Common Issues......................................................................................................24 

3.1.1 Primary Findings........................................................................................24 

3.1.2 Secondary Findings....................................................................................27 

3.2 Specific Issues........................................................................................................29 

3.2.1 Occupational Medical Dose ORAUT-TKBS-0028-3................................29 

3.2.2 Occupational Environmental Dose ORAUT-TKBS-0028-4 .....................31 

3.2.3 Internal Dose ORAUT-TKBS-0028-5.......................................................37 

3.2.4 External Dose ORAUT-TKBS-0028-6......................................................45 

4.0 Overall Adequacy of the Site Profile as a Basis for Dose Reconstruction ........................50 

4.1 Satisfying the Five Objectives...............................................................................50 

4.1.1 Objective 1: Completeness of Data Sources.............................................50 

4.1.2 Objective 2: Technical Accuracy..............................................................51 

4.1.3 Objective 3: Adequacy of Data.................................................................52 

4.1.4 Objective 4: Consistency among Site Profiles..........................................54 

4.1.5 Objective 5: Regulatory Compliance........................................................54 

4.2 Usability of Site Profile for Intended Purposes .....................................................54 
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4.2.1 Fernald Site Data Applied to Weldon Spring Workers .............................54 

4.2.2 Incomplete/Incorrect Information..............................................................54 

4.2.3 Incomplete Dose Reconstruction Recommendations................................55 

4.2.4 Lack of Defined Monitoring and X-ray Exam Criteria .............................55 

4.3 Unresolved Policy or Generic Technical Issues....................................................55 

5.0 References..........................................................................................................................56 

Attachment 1: NIOSH Technical Documents Considered During the Review Process...............59 

Attachment 2: Site Expert Interview Summary............................................................................61 
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ACRONYMS AND ABBREVIATIONS 

Advisory Board Advisory Board on Radiation and Worker Health 

AEC Atomic Energy Commission 

CATI Computer Assisted Telephone Interview 

CER Center for Epidemiological Research 

CFR Code of Federal Regulations 

Ci Curies 

DOE Department of Energy 

DR Dose Reconstruction or Dose Reconstructor 

dpm Disintegrations per Minute 

DU Depleted Uranium 

EEOICPA Energy Employees Occupational Illness Compensation Program Act of 2000 

EU Enriched Uranium 

GSD Geometric Standard Deviation 

keV Kilo electron Volt 

LAT Lateral 

LOD Limit of Detection 

MCW Mallinckrodt Chemical Works 

MCWND Mallinckrodt Chemical Works Nuclear Division 

MCWUD Mallinckrodt Chemical Works Uranium Division 

MDA Minimum Detectable Activity 

NIOSH National Institute for Occupational Safety and Health 

n/p Neutron-to-Photon Ratio 

NTA Eastman Kodak Nuclear Track Film Type A 

OCAS Office of Compensation Analysis and Support 

ORAUT Oak Ridge Associated Universities Team 

OTIB ORAU Technical Information Bulletin 

OW Open window 

PFG Photofluorography 

RU Recycled Uranium 

SC&A S. Cohen and Associates 

SEC Special Exposure Cohort 

SW Shielded window 

TBD Technical Basis Document 

TIB NIOSH Technical Information Bulletin 

U3O8, Triuranium Octoxide (called yellow cake) 

UF4 Uranium Tetrafluoride (called green salt) 
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UO2 Uranium Dioxide

UO3 Uranium Trioxide 

WS Weldon Spring 

WSCP Weldon Spring Chemical Plant 

WSRP Weldon Spring Raffinate Pit(s) 

WSQ Weldon Spring Quarry 
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1.0 EXECUTIVE SUMMARY 

This report provides the results of a review conducted by S. Cohen and Associates (SC&A) of 

the site profile for the Weldon Spring Plant, Weldon Spring, Missouri, developed by the National 

Institute for Occupational Safety and Health (NIOSH). This review was conducted during the 

period from January 2008–September 2008, in support of the Advisory Board on Radiation and 

Worker Health (Advisory Board) in the latter’s statutory responsibility under the Energy 

Employees Occupational Illness Compensation Program Act of 2000 (EEOICPA) to conduct 

such reviews and advise the Secretary of Health and Human Services on the “completeness and 

adequacy” of the EEOICPA program. 

The site profile for the Weldon Spring (WS) site consists of six documents created in 2005: 

• ORAUT-TKBS-0028-1 (Little and Meyer), Revision 0, June 28, 2005, and 

Revision 00 PC-1, June 30, 2008 

• ORAUT-TKBS-0028-2 (Little and Boyer), Revision 00, June 24 2005 

• ORAUT-TKBS-0028-3 (Lopez and Furman), Revision 00, June 24 2005 

• ORAUT-TKBS-0028-4 (Boyer and Little), Revision 00, June 28 2005 

• ORAUT-TKBS-0028-5 (Johnson and Falk), Revision 00, June 28 2005 

• ORAUT-TKBS-0028-6 (Langsted and Little), Revision 00, June 24 2005 

The Technical Basis Document (TBD) ORAUT-TKBS-0028-1, Weldon Spring Plant –

Introduction, was reissued with some minor changes on June 30, 2008; however, the changes in 

that document did not have an impact on this review. In this review, unless specified otherwise, 

the term “WS site” will be used to refer to the Weldon Spring site in general, to include the WS 

Chemical Plant (WSCP), the WS Raffinate Pits (WSRP), the WS Quarry (WSQ), and any 

surrounding areas encompassing the Mallinckrodt Chemical Works (MCW)/Department of 

Energy (DOE) operations. 

The WS site was constructed in the mid-1950s by the Mallinckrodt Chemical Works Nuclear 

Division (MCWND) to process uranium ore and other uranium materials for the Atomic Energy 

Commission (AEC). It was located on a 205-acre section of the Department of the Army’s 

17,232-acre Ordnance Works. According to TBD-2 (ORAUT 2005b), the WSCP was operated 

for AEC by the Uranium Division of MCW from 1957 to 1966. The WSCP processed materials 

from June 1957 to December 1966. Shutdown procedures were completed in 1967. It is 

estimated that there were approximately 600 employees at the site during peak production, of 

which about 300 would have handled uranium-containing materials. Four types of nuclear 

material were processed in the DOE-owned WSCP; natural uranium, depleted uranium (DU), 

slightly enriched uranium (EU) [some of these materials contained recycled uranium (RU)], and 

natural thorium. 

The WSCP sampled the incoming uranium-bearing ore for uranium content (usually contained in 

metal drums with approximately 70% uranium content), processed some of the ore, and shipped 

some of the ore to other facilities for processing. The chemical processing consisted of changing 
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the incoming material (mainly U3O8, called yellow cake) to UO3, UO2, and UF4 (green salt). The 

green salt was then converted to uranium metal ingots through a process of heating magnesium 

and the green salt in a steel “bomb” shell in a furnace. The uranium metal was then extruded 

into rods of various shapes and sizes for machining, cutting, descaling, cleaning, etc., for 

shipment to other facilities for further processing for use in nuclear reactors. Additionally, some 

of the uranium processed at the WSCP contained RU during 1961–1966 and EU at <1% 

enrichment during 1963–1966, with some DU used as a substitute for natural uranium, mainly at 

the pilot plant to study process flow. The WSCP also processed natural thorium at various times 

throughout its period of operations. 

The AEC turned over control of the WSCP to the Department of Defense (DOD) in 1967, when 

the U.S. Army was to convert some of the buildings for the production of Herbicide Orange. 

This project was cancelled in early 1969 and no production of the herbicide took place at the 

WSCP. Following this activity, no major work took place during the period 1969–1984. 

In 1985, assessment and monitoring began in preparation for remediation of the WS site for both 

chemical hazards and radiological hazards from the ordnance and uranium operations under the 

auspices of the Weldon Spring Site Remedial Action Project. The clean-up effort was essentially 

completed by 2002 with the removal or disposal of all buildings, foundations, pits, quarry, and 

related material. Some of this material was shipped offsite, but the majority of it was entombed 

in an above-ground disposal cell located on the original WSCP site. The WS site is currently 

under a monitoring and surveillance program. 

Scope and Approach 

SC&A reviewed the WS site profile documents for the following attributes, in accordance with 

TASK 1 - Site Profile Reviews, Subtask 1 - Site Profile Review Procedures (NIOSH 2004): 

• Completeness of Data Sources 

• Technical Accuracy 

• Adequacy of Data 

• Consistency among Site Profiles 

• Regulatory Compliance 

In preparation for this report, SC&A reviewed the six WS site TBDs in detail, along with many 

WS site-related documents located at the WS site Interpretive Center, at the various DOE/federal 

record centers, and on the O-Drive. SC&A also conducted onsite interviews with former WS 

site workers. From these reviews, SC&A developed a number of issues regarding the WS site 

profile. These issues were identified, consolidated, and grouped into findings. Findings that 

have the potential to significantly impact the results of at least some dose reconstructions are 

listed as Primary Findings, and those that are important, but may have less impact on the results 

of dose reconstruction, are listed as Secondary Findings. Additionally, items that could 

potentially lead to incorrect dose assignments because of errors, lack of clarity, inconsistencies, 

omissions, etc., in the TBDs are listed as Observations. 
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In this section, a brief summary of the issues are presented, followed by a summary of the 

primary findings. (Primary Findings, along with Secondary Findings, are further detailed in 

Section 3 of this report). SC&A then provides a discussion of the strengths of the TBDs, 

followed by recommendations for improvement at the end of this section, which are listed as 

Observations. 

Summary of Issues 

SC&A found that detailed documentation of radiation hazards, surveys, and potential exposures 

were not readily available or do not exist for the WS site, especially for the operational period of 

1957–1966 or the maintenance period of 1967–1984. Therefore, the underlying problem with 

the TBDs for the WS site is that they rely on recent WS site data (1985–2002), recent and some 

previous era environmental data, and very limited operational-period onsite data. Because of the 

limited WS site data and documentation, NIOSH also relied heavily on the Fernald site data and 

extrapolated it to the WS site TBDs. Unfortunately, the data/assumptions used for the Fernald 

site TBD are frequently estimates, instead of the results of measurements or documented 

information. Additionally, relatively recent data for the Fernald site was sometimes extrapolated 

to earlier time periods when sufficient data did not exist. The SC&A review of the Fernald site 

profile (SC&A 2006) points out the shortcoming of using these assumptions/data at the Fernald 

site. Understandably, SC&A has reservations concerning applying these questionable 

concepts/data from the Fernald site to the WS site profile. 

During the operational period, the WS site had a basic uranium bioassay and beta/photon 

badging program in place, and a limited site-parameter environmental monitoring program. 

However, the lack of routine personnel/egress contamination monitoring, consistent and 

documented badging policy (with geometry correction factors), comprehensive bioassay program 

that encompassed all the major radioisotopes brought on site, and an onsite environmental 

monitoring program for unmonitored workers leads to gaps in some of the information and data. 

NIOSH attempted to fill in some of these gaps with extrapolated operating conditions and data 

from other DOE sites. SC&A found some of these recommended methods to be uncertain, not 

sufficiently supported, or in some cases, potentially not claimant favorable. Additionally, a site 

profile should evaluate the accuracy, adequacy, and representativeness of the workers’ recorded 

internal and external dose data. SC&A could not find that NIOSH had performed a sufficient 

analysis of this type. 

The majority of material handled at the WS site was natural uranium. In addition, some RU, EU, 

and DU were also handled at the WS site, along with natural thorium. NIOSH acknowledges 

this in the WS site TBDs and makes some provisions for it, but concludes in general that because 

uranium is the most prevalent, it will dominate dose reconstruction. However, it cannot be 

assumed that because the majority of the material handled was natural uranium, then the other 

radionuclides are of a minor issue. Some workers involved in specific processes that handled 

these other radionuclides (and workers in the vicinity) had the potential of receiving substantial 

doses from these other radionuclides. 
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1.1 SUMMARY OF PRIMARY FINDINGS 

1.1.1 Findings Common to Several TBDs 

In reviewing the six site profile documents for the WS site, SC&A found several issues that were 

common to more than one of the documents. The following is a brief summary of the primary 

findings that reflect these issues. 

Lack of Personnel Contamination and Egress Monitoring 

The WS site TBDs do not mention the lack of monitoring equipment and procedures to check 

workers for contamination in the work places and upon leaving the controlled areas. During 

recent worker interviews, SC&A did not find that the workers recalled any regular egress 

monitoring, either between the operations areas to the non-operations areas (cafeteria, 

administration offices, labs, maintenance facilities, sidewalks, storage yards, grounds, etc.), or 

when leaving the plant site (guard shack, parking lots). Workers were apparently allowed to 

leave the controlled areas and the WS site without confirmation that they were not contaminated. 

This could have spread contamination to non-controlled 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. 

 

Inadequate Information Concerning Workers Status/Exposures for 1967–1984 

The WS site TBDs do not explicitly state when DOE employees and/or DOE contractors were no 

longer at the WS site after it stopped operations in December of 1966. It has not been 

determined if DOE employees and/or contractors were present or involved during 1967–1969 

when the U.S. Army was attempting to decontaminate and renovate buildings located at the 

WSCP; during the 1970–1984 monitoring and maintenance period; or during 1983–1984 when 

there were efforts to remediate leaks at the WSRP. If DOE contract personnel were present at 

the WS site soon after the shutdown in December 1966, they could have been exposed to 

numerous radionuclides during decommissioning, clean out, and revamping the facility for a 

completely different use. This could have lead 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 and/or recorded or grossly underestimated. 

If DOE employees and/or contractors were present at any of DOE’s WS facilities during the 

period 1967–1984, the TBDs need to be revised to include this period of dose evaluation for the 

site. Therefore, the issue of legal ownership of the property (and liability) as a function of time 

needs to be determined through federal/state/local records to determine if the TBDs should be 

revised to include additional time periods. 
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1.1.2.1

Individual Exposures versus Average Exposures 

The TBDs rely heavily on the fact that mostly natural uranium (>97%) was processed at the 

WSCP; therefore, the contributions from other forms of uranium (DU, EU, or RU) and other 

radionuclides (thorium, radium, etc.) are small compared to natural uranium. Whereas the most 

likely exposures (internal and external) may have been from natural uranium, this does not 

negate the fact that individuals or certain groups of workers may have been exposed to materials 

that contained greater concentrations of other forms of uranium and radionuclides, especially in 

or near plant locations dedicated to the other forms of radioactive material processing and in 

areas around discharge streams, waste, and raffinate pits. 

Assuming that natural uranium predominates as the source of a worker’s dose could lead to an 

underestimate of the worker’s correct dose if the worker was exposed to radioactive materials 

other than natural uranium. 

1.1.2 Findings Specific to a TBD 

SC&A reviewed the six TBDs for the WS site and has identified a number of issues that may 

impact the outcome of dose reconstruction for the WS site workers. The following is a brief 

summary of the primary findings that reflect these issues pertinent to each TBD. 

Occupational Environmental Dose ORAUT-TKBS-0028-4 

Lack of Atmospheric Monitoring Data for Operational Period 

There is no substantial site-wide atmospheric monitoring data available for the operational period 

to assure an accurate and integrated onsite environmental dose assessment. The TBD recognizes 

this lack and relied upon the use of dose estimates for the public derived from its reviews of the 

Fernald plant data to estimate the onsite environmental dose for the WSCP workers. This is 

problematic, in that raw emissions data from Fernald is not easily converted to environmental 

dose for the WS site workers when several emission points of varying geographic locations have 

to be considered, as well as the lack of knowledge that could place workers at specific locations 

during exposure events. SC&A believes that the limited environmental data presented in the 

TBD and the lack of environmental surveys of onsite locations over time does not support the 

supposition and/or conclusion of negligible dose to onsite personnel. 

Insufficient Data for Unmonitored Workers’ Internal Environmental Dose 

The TBD used one series of measurements (decontaminating 5-ton hoppers) and site parameter 

measurements to determine contributing intakes to non-bioassayed workers during 1957–1967. 

The hopper dust monitoring experiment consisted of measurements performed on one day under 

one particular condition, and the parameter measurements contributed very little (<1%) to the 

final results. This limited (in space, operations, and time) airborne/intake data is not sufficient to 

construct an adequate intake dose database for unmonitored workers at the WS complex, 

especially considering that a sizable fraction of the work force was not bioassayed on a routine 

basis during this period. 
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1.1.2.2

Lack of Validation for Maximum Environmental Dose 

The TBD fails to validate the adequacy of estimating the maximum environmental dose due to 

source terms at differing locations at the Weldon Spring Plant. In the current TBD, NIOSH has 

offered that existing air monitoring data do not distinguish the source of emissions; therefore, to 

some measure, it only allows evaluation of cumulative emissions and dose. The estimation of 

dose methodology currently being applied by NIOSH does not reasonably address maximum 

dose to workers who are not routinely monitored across the site, which could have been 50% of 

the site workers. 

SC&A believes that the lack of air monitoring stations in general and the overall lack of stations 

within a particular geographic location at the WSCP (of known higher releases of uranium and 

thorium) does not readily enable one to accurately estimate environmental dose using only the 

very limited existing air monitoring data. 

Internal Dose ORAUT-TKBS-0028-5 

Incomplete Assessment of Uranium Decay Products 

The TBD recommendations for dose estimate from decay products of U-238 are incomplete, and 

not always claimant favorable. The dose from inhaled Th-234 is not included along with the 

dose from inhaled U-238 in the dose calculations. What is included is the dose from Th-234 that 

builds up inside the body after an intake of U-238 takes place. Additionally, the dose 

contribution due to Pa-234m from the decay of Th-234 in the body also needs to be included in 

the internal dose calculations. While it is true that the Pa-234m outside the body only 

contributes to the external dose, the Pa-234m originating inside the body from Th-234 decay 

must be included in the internal dose calculations. 

Incomplete Assessment of Radon Exposure

The TBD describes the potential radionuclide exposure in the different buildings of the WSCP. 

Radon is listed as a source of exposure inside buildings 101, 103, 105, 403 and 407. However, 

the recommended approach used in the TBD to estimate radon doses is based on environmental 

radon concentrations for the areas within 100 meters of the assumed release point, which is the 

acid recovery plant stack. Using this approach requires that several assumptions be made, which 

results in large uncertainties in the dose estimates for workers located in indoor workplaces. For 

example, documentation shows that indoor radon concentrations averaged four times that of 

outside radon concentrations. 

Therefore, the approach recommend in TBD-5 is not always claimant favorable. NIOSH should 

propose a more reliable and claimant-favorable approach to the assess radon exposure for WSCP 

workers. 
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1.1.2.3

Different Solubility Classes Listed for the Same Element 

The TBD provides a list of solubility classes for uranium and thorium compounds in some of the 

buildings at the WSCP; however, the TBD lists different solubility classes for the same element. 

Because there were no means of separating isotopes of a given element at the WSCP, the 

chemical properties were the same for all uranium isotopes, as well as for all thorium isotopes. 

According to ICRP Publication 78 (ICRP 1997) the biokinetic behavior is the same for U-234, 

U-235, and U-238. The same applies for thorium Th-232 and Th-228. 

In view of the operations that took place at the WSCP, the TBD should provide 

justification/clarification concerning the use of different classes of solubility for the same 

element at the WS site. 

Missed Dose and Coworker Data Not Adequately Addressed 

The TBD does not address potentially missed internal doses, which should be part of a TBD for 

internal dose. The limits of detection (LODs) were generally high in the earlier years, which 

could result in significant missed doses. For the dose reconstructor to assign missed dose, the 

TBD needs to provide some information concerning the minimum detectable activity (MDA) for 

given bioassay techniques for the important radionuclides of concern at the WS site as a function 

of time. Additionally, the TBD provides some coworker internal dose information, but does not 

provide sufficient instructions for its use or the details of the data, such as the percent of workers 

bioassayed or the representativeness of the data (especially important at the WS site, because not 

all workers were bioassayed and none continuously). Also, most internal dose TBDs provide a 

summary section in the main text or as an appendix with recommendations and procedural steps 

for using coworker data. 

External Dose ORAUT-TKBS-0028-6 

Shallow and Extremity Doses Not Sufficiently Characterized 

The TBD briefly addresses dosimeter quantities, open window (OW), shielded window (SW), 

etc., and compares beta dose from NU, EU, and DU for shallow doses; additionally, electron 

dose is listed as >15 keV. But the TBD does not address geometry factors, total shallow dose, or 

extremity monitoring during the operational period. A geometry factor is needed for adequate 

dose assessment, because a film badge does not register the same dose as the worker’s 

tissue/organ is receiving from the betas and low-energy photons when handling, machining, 

scooping, etc., uranium containing materials. No WS site documents have been located that 

sufficiently address the change in film badge response as a function of radionuclide exposure, 

especially to low-energy photons and changes in beta energies. Additionally, there is no 

indication that routine extremity monitoring was performed at WS during the operational period. 

Badging Policy Not Consistent 

The TBD does not provide sufficient and/or consistent information concerning the badging 

policies at the WS site. This raises the question of what badging criteria were actually used in 
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Health for factual accuracy or applicability within the requirements of 42 CFR 82. 

practice and if workers not considered at the time to be exposed to radiation were potentially 

exposed but not monitored because of being in a pre-defined category. The lack of a consistent 

and documented badging policy may negatively impact dose reconstruction, because the dose 

reconstructor could assign an unbadged worker only external environmental dose when the 

worker should have been assigned coworker external dose. Additionally, badging policies could 

impact the validity of the coworker dose database. 

Lack of Sufficient Coworker Data Development for External Dose 

The TBD provides annual average gamma and beta exposures. However, the TBD does not 

provide any information concerning the details of this information, such as the number of data 

points for each entry, the percent of workers badged, the range of readings, if background was 

subtracted, if zeroes or outliers were included, if a threshold dose was used, etc. The data 

presented is a good start in creating a coworker database; however, in order to determine its 

validity and representativeness, there needs to be additional work performed on the data, as 

mentioned above. Plus, for internal coworker data, some guidance for use of the data in a 

summary form would be appropriate. 

1.2 SUMMARY OF STRENGTHS 

The WS site TBDs were written in six volumes, which assist the reader in accessing and 

analyzing the information in an orderly fashion. The TBDs addressed the different time periods 

(operational, shutdown, maintenance, and remediation) relevant to the WS site in a consistent 

manner. TBD-2 (ORAUT 2005b) provided a sufficient description of the site’s history from its 

origin in 1941 as an ordnance plant to its final state containing the above-ground disposal cell. 

References were well documented and editorial errors were kept to a minimum. (See 

Section 1.3, entitled Observations, for some of the errors that were located during this review.) 

The various authors were fairly consistent in the information they presented across the six TBDs, 

and made reasonable attempts to locate substitute data when it was missing for the WS site. This 

data was sometimes extrapolated from later WS site data, the Fernald site TBDs, or generic DOE 

documents, and these methods may be appropriate in some situations. However, because of the 

frequent lack of WS site-specific data/information, SC&A has concerns with using this approach. 

These concerns are expressed as findings in this report. 

NIOSH analyzed some of the environmental, internal (in-vitro bioassays), and external (gamma 

and beta) dose data and provided summary tables of this information in the appropriate TBDs. 

Some of this data will be helpful for use by the dose reconstructor for cases where there are gaps 

in the workers’ dose records, or for workers who were unmonitored. SC&A has reviewed this 

information and included their evaluation in the findings of this report. 

With the information available at the time of the writing of the first version of the WS site 

profile, the TBDs were reasonably well written. However, SC&A suggest that the TBD be 

revised with any new information NIOSH has acquired since 2005 and address SC&A’s 

concerns expressed in this report. 
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1.3 OPPORTUNITIES FOR IMPROVEMENT 

SC&A has identified some areas where changes in the TBDs would be beneficial to the claimant 

by preventing possible mistakes during dose reconstruction or clarifying items to make them less 

ambiguous. These are listed as Observations in this section. 

1.3.1 Observations – General 

Observation – Lack of Coverage of Offsite Activities 

Apparently, some work was performed by offsite contractors for the WS site, which consisted of 

inspection of uranium metal samples by cutting of the material and then irradiation using highenergy betatrons. This procedure could induce fission in uranium and create fission products 

that could emit radiation not normally encountered in a uranium facility, and expose nearby WS 

workers and transporters who may not have normally been badged; and it could have created 

inhalable radioactive material for which bioassays were not performed. This subject should be 

investigated and addressed in the appropriate TBDs. 

1.3.2 Observations – Occupational Medical Dose 

Equation 3-1, Dom = SnDi, is provided on page 6 of TBD-3 (ORAUT 2005c) and the individual 

terms in the equation are defined, except for the term “S.” This may have been meant to be the 

Greek symbol sigma “Σ” for summing, instead of an “S.” 

1.3.3 Observations – Environmental Dose 

Observation #1 – Application of Environmental Doses 

Section 4.1.2 of TBD-4 (ORAUT 2005d, page 6) states the following: 

The term occupational environmental dose refers to the radiation dose received in 

the course of work duties outside plant buildings, but on the WSCP site. This 

TBD considers internal and external exposures to radionuclides in the outdoor 

environment separately in calculating this dose. Dose reconstructors can use 

estimated occupational environmental dose to develop a reliable individual dose 

when a worker was not monitored adequately. 

However, this statement should be qualified to apply only to workers that were not routinely 

exposed and would not be considered a radiation worker by today’s standards. If the worker 

would be considered a radiation worker by today’s standard, then the dose reconstruction should 

be based on coworker dose data, not environmental dose data. 

Observation #2 – Special Uranium Curie 

The equation for the special uranium curie is correct on page 31 of TBD-5 (ORAUT 2005e), and 

on page 14 of TBD-4 (ORAUT 2005d), where it is stated that “The original data are reported in 
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units of special uranium microcuries, defined as the sum of 3.7 × 104 dps from 238U, 3.7 × 

104 dps from 234U, and 9 × 102 dps from 235U.” However, it goes on to state, “Converting to 

units of Bq, the special uranium μCi is multiplied by 3.7 ×104

 Bq/μCi and by a factor of 2.024 

to report total uranium activity” (emphasis added). The factor of 3.7 × 104

 Bq/μCi is correct, but 

the factor of 2.024 should be omitted, because the special uranium μCi already includes the 

2.024 factor [which consist of the sum of (3.7 × 104

 dps from 238U, 3.7 × 104 dps from 234U, and 

9 × 102 dps from 235U)/( 3.7 × 104 dps from 238U) = 2.024]. 

Observation #3 – Corrections to Text of TBD-4 

• The equation on page 5 should read, “WL Working Level = 1.3 × 105

 MeV of alpha 

energy in 1 liter of air;” not “105 MeV.” 

• The equation on page 5 should read, “WLM Working Level Month = Exposure from 

1 WL of radon daughters for 170 working hours;” not “...or radon...”

1.3.4 Observations – Internal Dose 

Observation #1 – Years of Thorium Use 

Table 5-2 (ORAUT 2005e, page 10) lists the starting date for potential Th-232 exposure as 1963, 

1965, and 1966 depending on the building. This should be verified, as it would seem that WS 

would have processed thorium fairly uniformly throughout the different buildings, at least on a 

yearly basis. 

Observation #2 – Changes in Text of TBD-5 

• The second paragraph on page 12 appears to be out of place in this location; it may be 

more applicable to the contents of page 9. 

• The last paragraph on page 12 contains an incorrect table and document reference; it 

should read, “Table 2-7 in ORAU (2005b) gives the annual (fiscal year) mass receipts of 

each of these feed materials;” not “Table 2-4 in ORAU (2005a)...” 

• The second paragraph on page 36 states that “Under these assumptions, the claimantfavorable assumption results in an annual exposure of 735 MAC-hr (in comparison to 

1,050 MAC-hr for Fernald)...” when actually it is 1,050 MAC-hr for the WS site, based 

on the definition of the MAC for the WS facility. Considering that the MAC for the WS 

facility was set at 70 dpm/m3

 compared to 100 dpm/m3 for the Fernald facility, it would 

be equivalent to 735 MAC-hr as defined for the Fernald facility. 
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1.3.5 Observations – External Dose 

Observation #1 – Changes in Text of TBD-6 

• Table 6-6, page 15, contains “?” where the gamma symbol should be, which causes some 

confusion while reading the contents of the table. 

• In Table 6-6, page 15, under the Report column, the text in the first and second row both 

refer to “Figures A-1 – A-6;” however, they describe different contents. Apparently, 

each one of them should refer to only a few of the Figures, not all six of them. 

Observation #2 – Missing Data in TBD-6 

• Table 6-2 (Summary of historical recorded dose practices) on page 12 is not complete, in 

that it does not contain any information (has blank spaces) for the time periods other than 

1958–1966. No Dosimeter measured quantities or Compliance dose quantities are 

provided for 1957, or the periods when EU and RU (Plant operations period Special case 

for enriched uranium) were processed, or 1967–1984 (Maintenance period), or for 

Landauer. This information is important during dose reconstruction to correctly interpret 

the recorded data and to determine if adequate data exist to assign accurate doses, 

especially for beta doses, which were prevalent at the WS site. 

• For the period 1957–1969, Table 6-14 (page 25) provides data for potentially missed 

gamma dose during 1957–1958 and 1959–1969; however, Table 6-16 only provides beta 

missed dose data for 1957–1966 (does not include 1967, 1968, and 1969). 
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2.0 SCOPE AND INTRODUCTION 

The review of the Weldon Spring (WS) site, in Weldon Spring, Missouri, was conducted during 

January – September 2008 by a team of SC&A health physicists and technical personnel. 

Almost all the records for the site have been declassified at this time. However, one member of 

the SC&A team held a “Q” clearance that permitted unencumbered access for this review, as 

needed. 

Some SC&A team members also participated in the MCW downtown St. Louis, Missouri 

(Destrahan Street), site profile review and were involved in the Special Exposure Cohort (SEC) 

petition for that site. Because the downtown site was a precursor for the WS site, experience 

gained at the first site was useful for the WS site profile review. 

SC&A understands that site profiles are living documents, which are revised, refined, and 

supplemented with NIOSH technical information bulletins (TIBs) as required to help dose 

reconstructors. Site profiles are not intended to be prescriptive or necessarily complete in terms 

of addressing every possible issue that may be relevant to a given dose reconstruction. However, 

future revisions in the WS site TBDs would serve to mitigate some of the gaps and issues raised 

in this report. 

2.1 REVIEW SCOPE 

Under the EEOICPA and federal regulations defined in Title 42, Part 82, Methods for Radiation 

Dose Reconstruction Under the Energy Employees Occupational Illness Compensation 

Program, of the Code of Federal Regulations (42 CFR Part 82), the Advisory Board is mandated 

to conduct an independent review of the methods and procedures used by NIOSH and its 

contractors for dose reconstruction. As a contractor to the Advisory Board, SC&A has been 

charged under Task 1 to support this effort by independently evaluating a select number of site 

profiles that correspond to specific facilities at which energy employees worked and were 

exposed to ionizing radiation. 

This report provides a review of the six site profile documents (ORAUT-TKBS-0028-1 through 

ORAUT-TKBS-0028-6) for the WS site in Weldon Spring, Missouri. The TBD ORAUT-TKBS0028-1, Weldon Spring Plant – Introduction, was re-issued with some minor changes on June 30, 

2008; however, the changes in that document did not impact this review. To date, these 

documents have not been supplemented by site-specific TIBs, but there are several generic TIBs 

that provide additional guidance to the dose reconstructor. 

Implementation guidance is also provided by so-called “workbooks,” which have been 

developed by NIOSH for selected sites to provide more definitive direction to the dose 

reconstructors on how to interpret and apply TBDs, as well as other available information. To 

date, no WS site-specific workbooks have been developed. 

SC&A, in support of the Advisory Board, has critically evaluated the WS site TBDs for the 

following: 
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• Determine the completeness of the information gathered by NIOSH in behalf of the site 

profile, with a view to assessing its adequacy and accuracy in supporting individual dose 

reconstructions

• Assess the technical merit of the data/information

• Assess NIOSH’s use of the data in dose reconstructions

SC&A’s review of this site profile document focuses on the quality and completeness of the data 

that characterized the facility and its operations, and the use of these data in dose reconstruction. 

The review was conducted in accordance with Standard Operating Procedure for Performing 

Site Profile Reviews (SC&A 2004) which was approved by the Advisory Board. 

The review is directed at “sampling” the site profile analyses and data for validation purposes. 

The review does not provide a rigorous quality control process, whereby actual analyses and 

calculations are duplicated or verified. The scope and depth of the review are focused on aspects 

or parameters of the site profile that would be particularly influential in deriving dose 

reconstructions, bridging uncertainties, or correcting technical inaccuracies. 

The WS site TBDs serve as site-specific guidance documents used in support of dose 

reconstructions. These site profiles provide the health physicist who conducts dose 

reconstructions on behalf of NIOSH with consistent general information and specifications to 

support their individual dose reconstructions. This report was prepared by SC&A to provide the 

Advisory Board with an evaluation of whether and how the TBDs can support dose 

reconstruction decisions. The criteria for evaluation include whether the TBDs provide a basis 

for scientifically supportable dose reconstruction in a manner that is adequate, complete, 

efficient, and claimant favorable. Specifically, this review was conducted using the criterion of 

whether dose reconstructions based on the TBDs would provide for robust compensation 

decisions. 

The basic principle of dose reconstruction is to characterize the radiation environments to which 

workers were exposed and determine the level of exposure the worker received in that 

environment through time. The hierarchy of data used for developing dose reconstruction 

methodologies is dosimeter readings and bioassay data, coworker data and workplace monitoring 

data, and process description information or source term data. 

2.2 ASSEESSMENT CRITERIA AND METHODS 

SC&A is charged with evaluating the approach set forth in the site profiles that is used in the 

individual dose reconstruction process. These documents are reviewed for their completeness, 

technical accuracy, adequacy of data, consistency with other site profiles, and compliance with 

the stated objectives, as defined in SC&A Standard Operating Procedure for Performing Site 

Profile Reviews (SC&A 2004). This review is specific to the WS site profile, and supporting 

TIBs; however, items identified in this report may be applied to other facilities, especially 

facilities with similar source terms and exposure conditions. The review identifies a number of 

issues and discusses the degree to which the site profile fulfills the review objectives delineated 

in SC&A’s site profile review procedure. 
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2.2.1 Objective 1: Completeness of Data Sources 

SC&A reviewed the site profile with respect to Objective 1, which requires SC&A to identify 

principal sources of data and information that are applicable to the development of the site 

profile. The two elements examined under this objective are (1) determining if the site profile 

made use of available data considered relevant and significant to the dose reconstruction, and 

(2) investigating whether other relevant/significant sources are available, but were not used in the 

development of the site profile. 

2.2.2 Objective 2: Technical Accuracy 

Objective 2 requires SC&A to perform a critical assessment of the methods used in the site 

profile to develop technically defensible guidance or instructions, including evaluating field 

characterization data, source term data, technical reports, standards and guidance documents, and 

literature related to processes that occurred at the WS site. The goal of this objective is to 

analyze the data according to sound scientific principles, and then evaluate this information in 

the context of dose reconstruction. 

2.2.3 Objective 3: Adequacy of Data 

Objective 3 requires SC&A to determine whether the data and guidance presented in the site 

profile are sufficiently detailed and complete to conduct dose reconstruction, and whether a 

defensible approach has been developed in the absence of data. In addition, this objective 

requires SC&A to assess the credibility of the data used for dose reconstruction. The adequacy 

of the data identifies gaps in the facility data that may influence the outcome of the dose 

reconstruction process. For example, if a site did not monitor all workers exposed to neutrons 

who should have been monitored, this would be considered a gap, and therefore an inadequacy in 

the data. An important consideration in this aspect of our review of the site profile is the 

scientific validity and claimant favorability of the data, methods, and assumptions employed in 

the site profile to fill in data gaps. 

2.2.4 Objective 4: Consistency among Site Profiles 

Objective 4 requires SC&A to identify common elements within site profiles completed or 

reviewed to date, as appropriate. In order to accomplish this objective, the WS site TBDs were 

compared to other TBDs previously reviewed. This assessment was conducted to identify areas 

of inconsistencies and determine the potential significance of any inconsistencies with regard to 

the dose reconstruction process. 

2.2.5 Objective 5: Regulatory Compliance 

Objective 5 requires SC&A to evaluate the degree to which the site profile complies with stated 

policy and directives contained in 42 CFR Part 82. In addition, SC&A evaluated the TBDs for 

adherence to general quality assurance policies and procedures utilized for the performance of 

dose reconstructions. 
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2.3 DOSE RECONSTRUCTION UNDER EEIOCPA 

In order to place the above objectives into the proper context as they pertain to the site profile, it 

is important to briefly review key elements of the dose reconstruction process, as specified in 

42 CFR Part 82. Federal regulations specify that a dose reconstruction can be broadly placed 

into one of three discrete categories. These three categories differ greatly in terms of their 

dependence on and the completeness of available dose data, as well as on the 

accuracy/uncertainty of data. 

Category 1: Least challenged by any deficiencies in available dose/monitoring data are dose 

reconstructions for which even a partial assessment [r minimized dose(s)] corresponds to a 

probability of causation (POC) value in excess of 50%, assuring compensability to the claimant. 

In some cases, such partial/incomplete dose reconstructions with a POC greater than 50% may 

involve only a limited amount of external or internal data. In extreme cases, even a total absence 

of a positive measurement may suffice for an assigned organ dose (based on the LOD) that 

results in a POC greater than 50%. For this reason, dose reconstructions in this category may 

only be marginally affected by incomplete/missing data or uncertainty of the measurements. In 

fact, regulatory guidelines recommend the use of a partial/incomplete dose reconstruction, the 

minimization of dose, and the exclusion of uncertainty for reasons of process efficiency, as long 

as this limited effort produces a POC equal to or greater than 50%. 

Category 2: A second category of dose reconstruction defined by federal guidance recommends 

the use of “worst-case” assumptions. The purpose of worst-case assumptions in dose 

reconstruction is to derive maximal or highly improbable dose assignments. For example, a 

worst-case assumption may place a worker at a given work location 24 hours per day and 

365 days per year. The use of such maximized (or upper bound) values, however, is limited to 

those instances where the resultant maximized doses yield POC values below 50%, which are 

not compensated. For this second category, the dose reconstructor needs only to ensure that all 

potential internal and external exposure pathways have been considered, and that the approach is 

scientifically supportable. 

The obvious benefit of worst-case assumptions and the use of maximized doses in dose 

reconstruction is efficiency. Efficiency is achieved by the fact that maximized doses avoid the 

need for precise data and eliminates consideration for the uncertainty of the dose. Lastly, the use 

of bounding values in dose reconstruction minimizes any controversy regarding the decision not 

to compensate a claim. 

Although simplistic in design, the TBD must, at a minimum, provide information and data that 

clearly identify (1) all potential radionuclides, (2) all potential modes of exposure, and (3) upper 

limits for each contaminant and mode of exposure to satisfy this type of a dose reconstruction. 

Thus, for external exposures, maximum dose rates must be identified in time and space that 

correspond to a worker’s employment period, work locations, and job assignment. Similarly, in 

order to maximize internal exposures, highest air concentrations and surface contaminations 

must be identified. 
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Category 3: The most complex and challenging dose reconstructions consist of claims where 

the case cannot be dealt with in one of the two categories above. For instance, when a minimum 

dose estimate does not result in compensation, a next step is required to make a more complete 

estimate. Or when a worst-case dose estimate that has assumptions that may be physically 

implausible results in a POC greater than 50%, a more refined analysis is required. A more 

refined estimate may be required either to deny or to compensate. In such dose reconstructions, 

which may be represented as a “reasonable” or “best-case” estimate, NIOSH has committed to 

resolve uncertainties in favor of the claimant. According to 42 CFR 82, NIOSH interprets 

“reasonable estimates” of radiation dose to mean the following: 

... estimates calculated using a substantial basis of fact and the application of 

science-based, logical assumptions to supplement or interpret the factual basis. 

Claimants will in no case be harmed by any level of uncertainty involved in 

their claims, since assumptions applied by NIOSH will consistently give the 

benefit of the doubt to claimants. (Emphasis added.) 

SC&A’s draft report and preliminary findings will subsequently undergo a multi-step resolution 

process. Prior to and during the resolution process, the draft report is reviewed by the DOE 

Office of Health, Safety, and Security, to confirm that no classified documents or information 

have been incorporated into the report. Resolution includes a transparent review and discussion 

of draft findings with members of the Advisory Board Working Group, petitioners, claimants, 

and interested members of the public. This resolution process is intended to ensure that each 

finding is evaluated on its technical basis in a fair and impartial basis. A final report will then be 

issued to the full Advisory Board for deliberation and a final recommendation. 

All review comments apply to Rev. 00 of the WS site TBDs, which are the most recently 

published versions. SC&A is aware of some minor revisions made to TBD-1 (ORAUT 2005a) 

in June 2008; however, this revised edition was not yet available on the Center for Disease 

Control (CDC) website at the time of the writing of this report. SC&A does not anticipate that 

these minor revisions will impact this review. 

Site expert interviews were conducted with former WS site workers to help SC&A obtain a 

comprehensive understanding of the radiation protection program, site operations, and historic 

exposure experience. 

Attachment 2 provides summaries of the interviews conducted by SC&A during the course of 

this review. The interviewees included a good cross-section of former WS site workers, 

including production, maintenance, safety, office, and radiological safety personnel that worked 

at the WS site at some point during the production period of 1957–1966. The interviews were 

conducted at the Weldon Spring Site Interpretive Center located at 7295 Highway 94 South, St. 

Charles, Missouri, and also with a former WS site worker in the St. Louis, Missouri, area. A 

telephone interview was conducted with a medical doctor closely associated with the WS site 

and its former workers. The interviews were conducted by Ron Buchanan (SC&A/Saliant Inc.) 

and Kathy Robertson-DeMers (SC&A/Saliant Inc.), from April 28–30, 2008, and on 

September 8, 2008. 
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Because of the singularity of purpose, limited operating period, and relatively small size of the 

WS site (as opposed to other DOE sites or national laboratories), SC&A did not submit a list of 

questions to NIOSH as part of its evaluation of the WS site TBDs. SC&A believed that the 

resources and time that would have been involved in submitting questions and obtaining 

responses could be more effectively spent in performing document research and other tasks for 

this site profile review. 

2.4 REPORT ORGANIZATION 

In accordance with directions provided by the Advisory Board and with site profile review 

procedures prepared by SC&A and approved by the Advisory Board, this report is organized into 

the following sections: 

(1) Executive Summary 

(2) Scope and Introduction 

(3) Vertical Issues 

(4) Overall Adequacy of the Site Profile as a Basis for Dose Reconstruction. 

Based on the issues raised, SC&A prepared a summary list of findings, which are provided in the 

Executive Summary. Issues are designated as Primary Findings if SC&A believes that they 

represent deficiencies in the TBD that need to be corrected and which have the potential to have 

a substantial impact on at least some dose reconstructions. Issues can also be designated as 

Secondary Findings or Observations if they simply raise questions, which, if addressed, would 

further improve the TBDs and may possibly reveal deficiencies that will need to be addressed in 

future revisions of the TBDs. Detailed analyses of the primary and secondary findings are 

provided in Section 3 of this report. 
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3.0 VERTICAL ISSUES 

SC&A developed the issues for the six WS site profile documents using the five objectives 

defined in SC&A’s review procedures (SC&A 2004). Some issues were related to more than 

one TBD and are covered under Section 3.1, Common Issues, and some are related to a specific 

TBD and are covered under Section 3.2, Specific Issues. The issues were identified, 

consolidated, and grouped into findings. Findings that could substantially impact the results of 

dose reconstruction for some workers are listed as Primary Findings, and those that are 

important, but may have less impact on the results of dose reconstruction, are listed as Secondary 

Findings. SC&A has also identified some areas where changes in the TBDs would be beneficial 

to the claimant by preventing possible mistakes during dose reconstruction, or where 

clarification of items would make them less ambiguous. These were listed as Observations. 

3.1 COMMON ISSUES 

In reviewing the six WS site TBDs, SC&A found several issues that were common to more than 

one of the documents. Therefore, to eliminate repetition, SC&A has consolidated these issues. 

The following are five areas that SC&A has identified where the present TBDs lacks sufficient 

information/data that may impact NIOSH’s ability to perform claimant-favorable dose 

reconstructions. 

 

3.1.1 Primary Findings 

Finding #1: Lack of Personnel Contamination and Egress Monitoring 

The WS site TBDs do not mention 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 

WS site during the operating period of 1957–1966. 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 2005e, page 11). During recent worker interviews, SC&A did 

not find that the workers recalled any regular egress monitoring, either between the operations 

areas to the non-operations 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 

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 1965b, 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 WS site. Contamination was apparently commonplace inside the process 

areas as evident by a statement in MCW Uranium Division (MCWUD) Summary of Health 

Protection Practices (MCW 1965b, 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 WS site document (Burr 1960): 
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His shoes and his gloves were especially loaded with green salt. The packing was 

done by foot...He had a respirator around his 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 WS site document (MCW 1959b). A little scale, cuttings, or dust from these operations 

would quickly contaminate the work area. 

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. 

Workers were apparently allowed to leave the controlled areas and the WS site 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. Because workers only periodically submitted urine samples, as 

described in TBD-5 (ORAUT 2005e), some of these individual internal exposures could have 

been missed. Additionally, personnel badges worn during working hours would not have picked 

up this offsite external dose on the workers. 

 

Finding #2: Inadequate Information Concerning Workers Status/Exposures for 1967–1984 

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

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

TBD-2 (ORAUT 2005b, page 22), it is indicated that no AEC contractors were present until 

August 1975 (this is reiterated on page 30 of TBD-2); however, Section 6.13.2, page 12 of 

TBD-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 WS site 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, during the 1970–1984 monitoring and maintenance period, or 

during 1983–1984 when there were efforts to remediate leaks at the WS Raffinate pit. 
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Sections 4.2.2.2 and 4.2.32 of TBD-4 (ORAUT 2005d); Sections 5.3.2, 5.4.2, 5.5.2, 5.5.3, and 

5.6.2 of TBD-5 (ORAUT 2005e); and Sections 6.1.3.2 and 6.1.3.3 of TBD-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 WS site during 1967–1984. If 

DOE contract personnel were present at the WS site soon after the shutdown in December 1966, 

they could have been exposed to numerous radionuclides during decommissioning, clean out, 

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 

WS site was no longer in place. Plant operating protocol would not have been in 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 lead 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. 

It should be determined if there were DOE or DOE contractor shutdown personnel, 

decontamination and decommissioning workers, or clean-up crews during the years immediately 

following the 1966 closure, and if there were guards and security staff during the period 1967–

1984. If DOE employees and DOE contractors were present at any of DOE’s WS facilities 

during the period 1967–1984, the TBDs need to be revised to include this period of dose 

evaluation for the site. Therefore, the issue of legal ownership of the property (and liability) as a 

function of time needs to be determine through federal/state/local records to determine if the 

TBDs should be revised to include additional periods. 

Finding #3: Individual Exposures versus Average Exposures 

In a number of places (ORAUT 2005d, page 11–12, and ORAUT 2005f, page 23), the TBDs rely 

on the fact that mostly natural uranium (>97%) was processed at the WS Chemical Plant; 

therefore, the contributions from other forms of uranium ( DU, EU, or RU) and other 

radionuclides (thorium, radium, etc.) are small compared to natural uranium. Whereas the most 

likely exposures (internal and external) may have been from natural uranium, this does not 

negate the fact that individuals or certain groups of workers may have been exposed to materials 

that contained greater concentrations of other forms of uranium and radionuclides, especially in 

or near plant locations dedicated to the other forms of radioactive material processing and in 

discharge streams, waste, and raffinate pits. 

Calculating the dose from the radioisotopes that produce 95% or 99% of the dose, as was done in 

TBD-4 (ORAUT 2005d, pages 11–12), to arrive at the conclusion that natural uranium over-rode 

all the other radionuclides is not claimant favorable to some workers monitored for only natural 

uranium who may have received a significant fraction of their internal and/or external doses 

(either chronic or acute) from other radionuclides. Additionally, non-bioassayed and unbadged 
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workers located near, but not in, a process area may have received unrecorded environmental 

internal and external doses from sources other than natural uranium. 

Likewise, it may not be claimant favorable to assume that all the beta doses were received from 

natural uranium (as in ORAUT 2005f, page 23), based solely on the fact that 97% of the material 

processed was natural uranium. Some workers may have received beta doses from other 

radioisotopes if they were involved in EU, RU, thorium, and other mission-specific projects or 

processes. 

Assuming that natural uranium predominates as the source of a worker’s dose could lead to an 

underestimate of the worker’s correct dose if the worker was exposed to radioactive materials 

other than natural uranium. 

3.1.2 Secondary Findings 

Finding #4: Recycled Uranium Not Adequately Recognized in the TBDs 

Recycled uranium (RU) and its associated radionuclides are one of the major concerns of former 

WS site workers. During onsite worker interviews, in Computer Assisted Telephone Interview 

(CATI) reports, and in potential SEC issues, the radionuclides from RU (plutonium, neptunium, 

U-236, and fission products, such as Tc-99) are listed as foremost concerns and among the items 

that the workers believe the government did not know, or was not fully disclosing the health 

hazards of. Therefore, RU should be clearly identified in the TBDs and included in the materials 

handled at the WS site, such as in the bullet points on page 6 of TBD-1 (ORAUT 2005a) and in 

Section 2.2.2.2 of TBD-2 (ORAUT 2005b, page 10), with equal importance compared to other 

materials. TBDs 1, 3, and 6 make no mention of RU; TBD-2 contains one paragraph on page 23, 

and TBD-5 (ORAUT 2005e) has a short section concerning RU on page 15 and mentions it on 

page 35, along with enriched (1%) uranium for 1963–1967. Of the six TBDs, the environmental 

dose TBD-4 (ORAUT 2005d) contains the most material concerning RU. On pages 10–12 of 

TBD-4, the assumption is made that because the amounts of RU handled at the WS site were a 

small fraction of the total uranium materials handled, then there is no need to consider RU and its 

associated contaminants to be potentially significant contributors to onsite environmental dose. 

This may be true on average or for chronic offsite environmental doses, but this assumption does 

not consider the fact that some workers or certain groups of workers may have received a 

substantial portion of their inhalation dose from RU and its associated contaminants for a 

significant amount of time near an RU-handling process. Although TBD-4 (ORAUT 2005d) did 

mention RU, it did not address the issue of RU for unmonitored workers environmental dose in 

sufficient detail. 

Not only are the details of the RU at the WS site important, but also the source of the RU is 

important, because RU from different DOE facilities contained different concentrations of 

radionuclides (DOE 1985). Therefore, the associated radiation hazards (internal and external) to 

WS workers would depend on the source of the RU. Defaulting to the Fernald site concerning 

RU issues [as recommended in WS TBD-5 (ORAUT 2005e, page 15)] may not be technically 

sound, especially in areas where data for Fernald is uncertain. SC&A’s review of the Fernald 

site profile (SC&A 2006) is summarized as follows: 
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The recycled uranium (RU) data are internally inconsistent and also inconsistent 

with some available DOE documentation. They are incomplete and do not 

appear to be claimant favorable for many workers and periods, though they are 

likely to be claimant favorable for many others. The problem in regard to 

adequacy of RU data is even more difficult for RU raffinate streams, in which the 

trace radionuclides, notably plutonium-239, thorium-230, and neptunium-237, 

became concentrated. 

Therefore, basing the WS site dose reconstruction recommendations on the Fernald site profile 

may lead to claimant-unfavorable assumptions and underestimated doses assigned to some 

workers. 

The statement on page 35 of TBD-5 (ORAUT 2005e) consists of the following: 

If specific information is not available in the worker’s file, the DR should 

consider the following default uranium source terms: 

· Natural uranium, before 1961 

· Natural uranium, recycled, 1961 to 1962 

· Enriched (1%) uranium, recycled, 1963 to 1967. (Emphasis added.)

This recommendation is not conducive to consistency in dose reconstruction and appears to be an 

over simplification resulting from the lack of sufficient information/data or investigation of the 

RU issue. 

Although RU was a small fraction of the total uranium processed at the WS site, its contribution 

to external and internal doses, especially to the workers associated with processing it and 

exposed to it by products, could be of significance in dose reconstruction. Therefore, RU should 

play a more predominate role in the TBDs and in dose reconstruction. 

Finding #5: Lack of Accident/Incident Documentation Not Sufficiently Addressed 

The WS site TBDs do not address accidents or incidents at the WS site (or the apparent lack of 

their documentation being readily available), except for the brief mention of two accidents on 

page 27 of TBD-2 (ORAUT 2005b). Accidents and incidents that could potentially release 

material to the operations area and to unmonitored workers onsite are important at the WS site, 

because the radiological hazards may not have been fully recognized, investigated, or 

documented at the time of its occurrence. During onsite interviews with former WS site 

workers, the subject of accidents/incidents was mentioned 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 
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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 

was written up in a MCW report (MCW 1961) and the dose reconstructor evaluated the dose 

received from the accident during the dose reconstruction process. However, this may not 

always be the case. 

Accounting for accidents and incidents that have the potential to lead to radiation exposures are 

problematic at a number of DOE and DOE contractor sites. The WS site is no exception; it is 

especially prone to this problem, because uranium was treated mostly as a chemical rather than a 

radiological hazard during the plant’s operational period. Therefore, occurrences may not have 

been documented sufficiently or be readily available to the dose reconstructor to allow dose 

reconstruction by today’s standards. Although NIOSH’s WS site profile cannot correct the lack 

of documentation in the workers’ DOE files, it can provide information concerning where the 

dose reconstructor might search to locate any accident or incident files, and outline some of the 

major occurrences that the dose reconstructor should be aware of to match them to possible 

exposures for a given case. By the nature of the operations at the WS site, most doses came from 

chronic low-level exposures; however, unusual occurrences, accidents, and incidents could lead 

to acute intakes and/or contamination that greatly exceed the normal levels. 

3.2 SPECIFIC ISSUES 

SC&A reviewed the six TBDs for the WS site and has identified a number of issues that may 

impact the outcome of dose reconstruction for the WS site workers; these are listed in the 

following section as findings associated with each specific TBD. 

3.2.1 Occupational Medical Dose ORAUT-TKBS-0028-3 

Background and Introduction 

The current version of the WS site TBD for occupational medical dose (ORAUT 2005c) is a 

relatively short TBD, and contains some general information and data gathered from DOE site 

profiles and technical documents. There is very little information available concerning the WS 

site occupational medical procedures, equipment, x-ray exam frequency, etc. Some references 

are made to MCW documents associated with the Destrahan Street location. The TBD does 

present dose conversion factors (DCFs) and organ dose estimates for a number of organs/tissues 

for the periods prior to 1970 and after 1985 taken from ORAUT-OTIB-0006 (ORAUT 2005g). 

Because of the lack of WS site documentation in the occupational medical area, this TBD is by 

nature mostly a genetic document. SC&A has reviewed this TBD and has the following 

Secondary Findings pertinent to the WS site.

Finding #6: Inconsistence in Frequency of X-ray Exams 

TBD-3 (ORAUT 2005c, page 8) assumes annual x-rays for all periods, and in Section 3.1.2 

(page 7), it recommends annually from 1955 through 1966. However, in the same paragraph it 

states, “A review of pre-1970 files indicates that, approximately 30% of the time, workers 
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received two sets of chest x-rays in a period of 9 months or less (excluding x-rays for termination 

of employment);the files do not provide reasons for this.” (This would equate to an overall 

average of 1.25 x-ray exams per worker per year.) In the last paragraph of Section 3.1.2 

(page 7), it suggest an x-ray exam was conducted every 2 or 5 years for post-1985 workers. And 

in the next to the last paragraph on page 13 of the TBD, it recommends annual chest x-rays for 

1958–1964. 

While the frequency of x-ray exams are discussed in Section 3.1.2 of TBD-3 (ORAUT 2005c), 

no mention is made of the frequency of retake exams (because of technical or medical 

complications) that might add to the total number of x-ray exams performed. ORAUT-OTIB0006 (ORAUT 2005g, page 14) states, “Retakes should serve as a signal to give special 

consideration to the evaluation of technique factors, and hence the resultant dose calculations.” 

This indicates that retakes were not an uncommon event. 

TBD-3 (ORAUT 2005c) should recommend a defined set of claimant-favorable x-ray exam

schedules, so that dose reconstructions can be performed in a consistent manner. It should also 

be determined if some workers or groups of workers [such as those that wore respirators, were 

food handlers (tested for tuberculosis), etc.] may have had more frequent x-rays exams; perhaps 

this was the reason for the increase in frequency as noted in Section 3.1.2 of the TBD.

Finding #7: Photofluorography Exams Not Adequately Addressed 

TBD-3 (ORAUT 2005c) mentions photofluorography (PFG) exams on page 7. However, no 

recommendations to the dose reconstructor are made concerning this type of exam, other than 

that there had not been any indications that PFG exams were conducted at the WSCP. ORAUTOTIB-0006 (ORAUT 2005g, page 21) states, “It is reasonable to presume that at least some of 

the occupational medical diagnostic chest x-rays with the DOE and its predecessor organizations 

were accomplished by PFG and, in the absence of data to the contrary, the use of PFG should be 

assumed to ensure claimant-favorable dose reconstructions.” Table 7-6 of ORAUT-OTIB-0006 

(page 24) also indicates that DOE/AEC facilities used PFG equipment from 1953–1968, which 

would encompass the 1957–1966 operating period at WSCP. If PGF equipment was not located 

at the WSCP site, workers may have had occupational PFG exams performed at offsite locations, 

such as Barnes Hospital Labs, which serviced MCW workers in the earlier years. TBD-3 

(ORAUT 2005c) does not show evidence of investigating this subject sufficiently (such as 

checking Missouri state records, etc.) to justify discounting the possibility that some WS site 

workers received PGF exams. 

Finding #8: Lumbar Spine Exams Not Addressed 

TBD-3 (ORAUT 2005c) makes no mention of lumbar spine x-rays and states on page 7 that, 

“Therefore, the analysis for this TBD assumed annual PA and LAT chest x-ray examinations for 

all employees, and considered no other view.” This excludes both PFG and lumbar spine exams. 

Lumbar spine exams were sometimes performed for workers that performed heavy and strenuous 

work, such as laborers and construction workers, or those with back problems. ORAUT-OTIB0006 (ORAUT 2005g, page 21) states, “However, the possibility of periodic lumbar spine 

examinations, including an exit employment physical examination should not be precluded.” 

Therefore, TBD-3 should address the issue of lumbar spine exams for WS site workers. 
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Finding #9: Use of ICRP-34 Instead of ICRP-74 

TBD-3 (ORAUT 2005c) utilizes ICRP 34 (ICRP 1982) instead of ICRP 74 (ICRP 1996), which 

was used in NIOSH’s OCAS-IG-001 (NIOSH 2002) to determine absorbed dose from kerma 

values. Preliminary studies by SC&A indicate that the use of ICRP 34 may tend to 

underestimate the absorbed dose. ICRP 34 does not have 10 organs that are now in ICRP 74. 

The use of ICRP 74 is particularly important when the medical examinations included PFG chest 

x-ray exams, where doses can double or triple based on the differences between ICRP 34 and 

ICRP 74; for PA and lateral x-rays, the underestimations are not as significant. This issue 

amplifies the need to ascertain whether WS site workers received PFG exams, as outlined in the 

previous finding. 

3.2.2 Occupational Environmental Dose ORAUT-TKBS-0028-4 

Background and Introduction 

In TBD-4 (ORAUT 2005d), most of the environmental dose to WSCP workers is attributed to 

uranium and thorium. Internal dose from exposure outside the process areas is assumed to be 

due mainly to facility releases and resuspension from contaminated soils, or from waste storage 

and holding areas (WSQ and WSRP). Source terms are derived mainly from limited process 

knowledge and calculated or estimated maximum releases from stacks and vents. Because 

uranium was viewed mainly as a chemical hazard rather than a radiological hazard, little actual 

onsite environmental measurement data exist for the early years of operations, especially for 

unmonitored workers on the site premises, but outside the immediate operating areas. Most 

effluent data utilized in the TBD were derived from several annual environmental reports for the 

years 1981 to 2002, inclusive. Most releases and subsequent doses were presumed to be 

primarily from natural uranium (mostly U-238); lesser contributors to environmental dose were 

Th-232 and Th-230. Notably, the Th-232 was not monitored routinely, as it was believed to be a 

minor contributor to dose. The TBD concludes that estimates of environmental dose can be 

derived strictly from uranium air monitoring data, as it should account for resuspension of other 

radionuclides in soil. Because of the lack of environmental monitoring for unmonitored workers 

during the operational period, this TBD relies heavily on data obtained during the remedial 

period, environmental parameter measurements, and the air concentration measurements during a 

hopper cleaning event. 

The current version of TBD-4 (ORAUT 2005d) was published with significant data gaps in the 

environmental data before 1985. Therefore, the current TBD version already warrants a future 

revision due to these existing data gaps, especially because of the need for historical data during 

the operational period (1957–1967). Any revisions should include additional information 

pertinent to onsite environmental monitoring and effluent data collected, and any applicable 

information that comes from NIOSH responses to SC&A’s site profile review that have occurred 

since the publication of this TBD. 

SC&A has reviewed the TBD, as written, and has identified the following findings. 
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Primary Findings 

Finding #10: Lack of Atmospheric Monitoring Data for Operational Period 

There is no substantial site-wide atmospheric monitoring data available for the operational period 

to assure an accurate and integrated environmental dose assessment. The current TBD-4 

(ORAUT 2005d) recognizes this lack of site-wide atmospheric monitoring data. SC&A has 

previously emphasized the need for such site-wide data during crucial periods and questioned 

whether NIOSH could reasonably assess environmental dose, using only limited environmental 

data, as presented in this TBD. NIOSH has relied upon the use of dose estimates for the public, 

derived from its reviews of the Fernald plant data, to estimate the onsite environmental dose for 

the WSCP workers. This is problematic in that raw emissions data from Fernald is not easily 

converted to environmental dose for the WS site workers when several emission points of 

varying geographic locations have to be considered, as well as the lack of knowledge that could 

place workers at specific locations during exposure events. The TBD also evidences that 

effluent data before 1981 has not been identified and/or validated, and therefore, has relied solely 

on an incomplete air monitoring data point as its basis. NIOSH should therefore consider the 

need to revise the TBD or better demonstrate that use of this approach is claimant favorable. 

The TBD describes the predominant operation of the WSCP (1957–1967) as basically a limited 

uranium conversion operation to produce metal for shipment offsite. It is further argued that 

newly formed metals and other products were not prone to any long-term storage and would 

release minimal environmental contaminants. It is also concluded that only minimal releases of 

uranium occurred up to 1985 as the facility was shut down from 1967 to 1985. Although 

thorium was monitored in more recent years, the TBD emphasizes the fact that significant 

quantities of Th-232 and Th-230 were not introduced at WSCP, and accordingly present a lower 

(less than 5%) environmental dose hazard. Based upon these conclusions, NIOSH believed an 

estimated atmospheric dispersion model for WSCP was not warranted to further estimate 

environmental dose. The TBD further concludes, based solely upon limited air monitoring data 

after 1981, that environmental doses to all onsite workers would be negligible (i.e., less than 

100 mrem per year) during the monitoring and pre-restoration period (1967–1992). SC&A 

believes that the limited environmental data presented in the TBD and the lack of environmental 

surveys of onsite locations over time does not support the tacit conclusion of negligible dose to 

onsite personnel. 

Finding #11: Insufficient Data for Assigning Unmonitored Workers Internal 

Environmental Dose 

TBD-4 (ORAUT 2005d, page 14) used one serial of measurements (decontaminating 5-ton 

hoppers, August 1960) (Holt 1960) and site parameter measurements to determine contributing 

intakes (Table 4-6 of TBD-4) to non-bioassayed workers during 1957–1967. The hopper dust 

monitoring experiment was measurements performed on one day under one particular condition, 

and the parameter measurements contributed very little (<1%) to the final results. The following 

are some of the reasons that it may not be a technically sound approach to use this limited data to 

assign unmonitored workers’ internal environmental dose over a period of 11 years: 
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• There are no indications if this operation (cleaning the hopper) would have constituted a 

representative source term for all operations over the entire 11-year period. 

• There are no other WS site operational measurements to compare these result to in order 

to assess if they might be at the high, average, or low end of the air concentration range. 

• The WS facility was a relatively large complex. Air concentration in one location on a 

given day most certainly would not be representative of all locations on all days. 

• The site environmental parameter measurements had very little influence on the resulting 

average value (Table 4-5, max = 1.7E-2/4.4 Bq/m3 = 0.4%; hence, the final values for 

1957–1967 were essentially derived from the one hopper monitoring experiment). 

• Validating the results of this measurement by comparing it to the average estimated

value for Fernald (see ORAUT 2005d, page 16) is not supported, because conditions/ 

operations at the two facilities would not be sufficiently identical on a daily basis; plus 

the Fernald value was based on an estimated value, not a measured value. 

This limited (in space, operations, and time) airborne/intake data is not sufficient to construct an 

adequate intake database for unmonitored workers at the WS complex; especially considering 

that a sizable fraction of the work force was not bioassayed on a routine basis during this period. 

Finding #12: Lack of Validation for Maximum Environmental Dose 

The TBD (ORAUT 2005d) fails to validate the adequacy of estimating the maximum 

environmental dose due to source terms at differing locations at the WS site. In the current TBD, 

NIOSH has offered that existing air monitoring data do not distinguish the source of emissions; 

therefore, to some measure, it only allows evaluation of cumulative emissions and dose. The 

estimation of dose methodology currently being applied by NIOSH does not reasonably address 

maximum dose to workers who are not routinely monitored across the site. At WSCP, as many 

as 50% of the site workers were not routinely monitored. 

SC&A believes that the lack of air monitoring stations in general and the overall lack of stations 

within a particular geographic location at the WSCP (of known higher releases of uranium and 

thorium) do not readily enable one to accurately estimate environmental dose. It will be difficult 

for the dose assessor to accurately estimate environmental dose to an individual without more 

comprehensive air monitoring data, environmental surveys, and substantial knowledge of where 

workers were located during such episodic and acute releases. 

The TBD also does not attribute any significant environmental dose to pre-existing 

contamination of the environment from plant operations. Very limited environmental analyses 

of soils are used to suggest that nearly all uranium contamination is attributable to natural causes. 

The aerial radiological survey referred to in TBD-4 (ORAUT 2005d, page 25) was performed 

after the WSCP ceased operation by approximately a decade. There is no supporting evidence 

presented to indicate that the resulting exposure rate (61–88 mrem per year) resulting from this 

later measurement would have been applicable during the operational period, given the plant has 

operated for 10 years, had a reasonably high throughput (14,000 tons per year), and experienced 

numerous incidents and episodes of environmental releases. For monitored workers (nearly 
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50%) of the population prior to 1992 when restoration commenced, it is assumed that the 

dosimeters that were provided would reasonably include an environmental dose component. 

This approach tends to discount any potential dose resulting from inhaled materials that would 

not be assessed by dosimetry badges that monitored only ambient gamma radiation. Also, some 

workers were not included in sufficient routine bioassay programs to assess internal dose. For 

unmonitored workers (nearly 50% of the population), environmental dose is attributed to only 

ambient (gamma) radiation levels. Similarly, this approach does not consider internal deposition 

or variations due to spatial locations on the site or episodical releases. 

To this extent, NIOSH has recently agreed for other sites that using emissions data alone to 

estimate air concentrations may not be appropriate. There is a need for more historic 

environmental data to fill the gaps for sampling and air monitoring for a larger group of 

radionuclides, such as thorium that was disposed of in the WSQ. 

Secondary Findings 

Finding #13: The TBD Lacks Sufficient Effluent Data Prior to 1967 

The TBD (ORAUT 2005d) has relied, to the extent possible, on data derived from known source 

terms, yet the validation of that data remains in question. NIOSH/ORAUT should validate this 

data against any remaining effluent data or reports for the period of 1992 through 2002, when 

restoration took place and sufficient monitoring data exists. 

NIOSH has indicated that an obstacle to its evaluation is that effluent data back to the 1950s has 

not been found at the time this TBD was written and approved for dose assessor use. Another 

source of ongoing controversy involves the development of coworker data that could possibly be 

used in some instances to address unaccounted for doses from environmental releases. This is 

particularly important, due to the very large numbers of unmonitored workers at WSCP. 

Another significance of the lack of environmental data is the lack of any early thorium data as 

there is no basis to estimate thorium releases prior to 1967, even though thorium was first stored 

and used at WSCP as far back as 1958. Also, significant quantities of thorium in the WSQ were 

not routinely sampled until after 1985. It would be important to locate any early (1950s and 

1960s) air monitoring or soil analyses data to validate the presence or absence of these nuclides 

in the environs at WSCP. 

SC&A believes that the lack of substantial environmental data before 1967 warrants closer 

scrutiny to effectively assess all doses from environmental sources to ensure claimant 

favorability. 

Finding #14: Stated Uranium/Thorium/Radium/Lead Ratios should be used with Caution 

TBD-4 assumes that during the operations period, Th-230 was 5% of the U-238 activity, Ra-226 

was 1% of the U-238 activity, and Pb-210 was 1% of the U-238 activity (ORAUT 2005d, 

page 9). These values may have been applicable for some locations and time periods at the WS 

site; however, this may not have been true for certain locations, as acknowledged in TBD-5 
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(ORAUT 2005e, page 14). For example, a 1967 WS site document (WS 1983, page 2) lists the 

thorium/uranium (no isotopic information provided) concentrations as 63,600/27,600 = 2.3; 

much greater than the 0.05 assumed. Another example is a 1983 WS document (Eberline 1983, 

page 10), which shows that the raffinate pits contained much higher concentrations of Th-230 as 

compared to U-238. The ratios for sludge samples from the pits were as follows: 

• Pit #1: (Th-230/U-238) = 33.8 

• Pit #2: (Th-230/U-238) = 51.1 

• Pit #3: (Th-230/U-238) = 26.9 

• Pit #4: (Th-230/U-238) = 2.6 

These samples were analyzed on August 18, 1983; therefore, there was decay product in-growth 

during the period from the end of operations to the sampling date (approximately 18 years 

compared to 11 years of plant operations). However, the Th-230/U-238 ratios were so much 

greater than 0.05, that even a small in-growth, or residual thorium, would exceed the 5% level. 

Therefore, the TBD stated value for Th-230 as 5% of the U-238 concentration should be used 

with caution as it may not apply to all situations of potential exposure at the WS site during the 

operational period. 

Finding #15: Natural Thorium-232 Not Always Negligible 

TBD-4 (ORAUT 2005d, page 9) assumes that because the amounts of natural thorium handled/ 

processed at the WS site were a small fraction of the total uranium materials handled and 

processed, natural thorium is probably not a significant contributor to environmental inhalation 

doses during the operational period. This may be true on average, but this assumption does not 

consider the fact that some workers or certain groups of workers may have received a substantial 

portion of their inhalation dose from thorium and it decay products for a significant amount of 

time near a thorium handling process, or from operations that concentrated thorium, such as the 

raffinate pits. A 1983 WS document (Eberline 1983, page 10) shows that the raffinate pits 

contained significant concentrations of Th-232 as compared to U-238; approximately 20% on 

average. A 1965 WS site document (MCW 1965a) concerned with thorium operations states the 

following: 

It is observed that the pot denitration operations are of marginal adequacy. 

Procedures in use for handling the “light” thorium oxide produced visible air 

concentrations in open operating areas.... and, ...Control of this situation when 

thorium is involved is complicated further due to the unreliability of conventional 

bio-assay methods in documenting internal exposures.

This latter statement is supported by an article concerned with the problems of thorium bioassays 

even today (Stradling et al. 2004). 

Therefore, assuming that Th-232 was insignificant as compared to uranium should be used with 

caution as it may not apply to all situations of potential exposure at the WS site during the 

operational period. 
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Finding #16: Use of External Environmental Dose from Protracted Fernald Estimated 

Data 

TBD-4 (ORAUT 2005d, page 25) outlines the method used to determine the environmental 

external dose values at the WS site for the time period of 1957–1967. The external dose of 

383 mrem per 2000 hours (1 work-year) was derived from using the dose information from the 

Fernald site TBD-4 (ORAUT 2004a) and is listed in Table 4-11 of TBD-4 (ORAUT 2005d, 

page 27) for the WS site. The data from the Fernald site was not measured directly, but was 

derived from measurements post-1976 and then projected back to the pre-1976 period by scaling 

of production levels. This methodology is unreliable and may not result in appropriate external 

environment dose assignments to WS site workers for several reasons: 

• It would be questionable if the external environmental doses at the Fernald site would be 

sufficiently similar during the post-1976 period when the dose measurements were 

performed to make them applicable to most of the pre-1976 years, even at Fernald. 

• Although the Fernald and WS sites both processed uranium, their source terms and 

physical site characteristics (types/amounts of material discharged to the air/soil/water, 

the contour of the land, the soil/vegetations, the rainfalls/winds, etc.) would not be 

sufficiently compatible to allow reasonable application of the Fernald site data to the WS 

site, as was done in TBD-4. 

• The external dose value of 1675 mrem/year represents a one-size fits all locations (at 

WSCP and WSQ) for 11 years (1957–1967). This is a broad generalization that is not 

supported. 

TBD-4 (ORAUT 2005d) only lists the ore concentrate stored onsite, the raffinate pits, and the 

quarry as sources of external environmental exposure during the operational period (1957–1967). 

This omits any external radiation originating from discharges from the process buildings 

(through the stacks or out of the openings in the buildings); as direct radiation, as particulates in 

the air, or from the settling out of radioactive material on the soil/surfaces. These are source 

terms that should be included in external environmental dose considerations. 

In view of this information, it is concluded that TBD-4 does not provide sufficient data to allow 

the construction of an adequate database for assigning external environmental doses to 

unmonitored workers at the WS complex with reasonable confidence. Additionally, because a 

considerable fraction of the workers at the WS site were not monitored, this could potentially 

impact a significant number of workers. 

Finding #17: Episodic Releases 

TBD-4 (ORAUT 2005d) details some of the known episodic releases, but fails to give significant 

estimates of environmental dose for those episodes or provide consideration for unknown 

incidents. 

The TBD also notes that there is a paucity of information regarding episodic releases, resulting in 

potential environmental contamination of workers. NIOSH believes the purpose of the TBD is
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not to provide estimates of dose, but rather to offer estimates of source terms to be used by dose 

assessors to estimate the dose to the individual claimant. Effluent data used by dose assessors 

would often include quantities for both routine and episodic releases; however, NIOSH 

recognizes that significant current gaps exist in this information. 

Episodic releases detailed in the TBD are limited to two events. The most significant event was 

a spill of uranyl nitrate. Estimated doses to the immediately impacted workers were made; 

however, no dose to the nearest public member and unmonitored onsite workers are estimated. 

Because there were no apparent environmental measurements performed during or after the 

event, it is not possible to validate the level of environmental exposure from the incident. The 

other event described is the exposure of a worker to soluble uranium in a dust enclosure. This 

event was also not monitored, and reportedly no environmental samples were taken. SC&A 

believes this, as well as statements in the TBD, do not seem to support the idea that 

environmental exposures were necessarily negligible and resulted mostly from incident exposure 

to resuspended uranium compounds. To the contrary, the lack of sufficient environmental data 

would suggest the need to develop a maximum exposure scenario for numerous events. 

Although not all events were recorded, knowledge of potential releases and events at this site 

could be used to better estimate maximum exposures that are claimant favorable. 

3.2.3 Internal Dose ORAUT-TKBS-0028-5 

Background and Introduction 

TBD-5 (ORAUT 2005e) was written to provide the dose reconstructor with recommendations 

concerning internal dose reconstruction at the WS site during the operational period of 1957–

1966, the monitoring period 1975–1984, and the remediation period 1985–2001 (it does not 

include the period 1967–1974). The TBD covers the major areas of concern, such as radioactive 

material source terms, air concentrations, the assessments of intakes, and the in-vitro and in-vivo 

measurements. During the operational period, 1957–1966, the workers at WS were periodically 

monitored by urinalysis for uranium, but were not bioassayed for other radionuclides. Some 

one-time qualitative in-vivo bioassays for thorium were conducted in July 1966. Because there 

was limited onsite uranium and no thorium or radon air sampling up until 1985, the authors of 

this TBD relied heavily on the Fernald site internal dose TBD-5 (ORAU 2004b) and WS site 

environmental and remediation monitoring data, and then applied this data to the WS site during 

the operating period. Natural, enriched, depleted, and recycled uranium and natural thorium 

were included as potential internal dose contributors. SC&A reviewed the TBD according to 

Site Profile Reviews Procedures (NIOSH 2004) and has the following findings.

Primary Findings 

Finding #18: Incomplete Assessment of Uranium Decay Products 

TBD-5 (ORAUT 2005e) recommendations for dose estimates from decay products of U-238 are 

incomplete, and not always claimant favorable. For example, the following is stated on page 13 

of the TBD: 
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The materials handled at WSCP were uranium concentrates and, to some extent, 

natural thorium. The short-lived decay products of 238U, which are 234Th (24-d 

half-life) and 234mPa (1.175-min half-life), would have built into equilibrium 

before the material was handled. Thorium-234 and 234mPa emit beta particles. 

The dose from inhaled 234Th is included in the dose from 238U as it builds into 

equilibrium in the body in a relatively short period of time (less than eight 

months). The 234mPa beta is a high-energy beta and contributes to the external 

dose but, due to its short half-life, does not in itself contribute to internal dose. 

SC&A does not agree with this analysis for the following reasons. 

Inhaled Th-234

The dose from inhaled Th-234 is not included when the dose from inhaled U-238 is calculated. 

What is included is the dose from Th-234 that builds up inside the body after an intake of U-238 

takes place. Th-234, with its 24-day half-life, and Pa-234, with its 6.7 hour half-life, would be 

present along with, and in about equal concentrations as, U-238 in the yellowcake, and hence in 

the workplace air. The same analysis applies to Ra-228 and Ac-228 from natural thorium. The 

radionuclides from the uranium and thorium decay series present in the workplace needs to be 

considered as an additional source of exposure, independent of the U-238, U-235, or Th-232 

inside the body. ICRP Publication 78 (ICRP 1997) points out that if there is a mixture of 

radionuclides in the workplace, those radiologically significant ones need to be taken into 

consideration in the dose estimate (ICRP 1997, page 33): 

 

Workers may be exposed to a mixture of radionuclides and this must be taken into 

account in calculating pre-determined derived investigation levels. It will often 

be the case that only a few radionuclides in the mixture make a significant 

contribution to the committed effective dose. In principle, the radiologically 

significant radionuclides should be identified and monitoring programmes should 

be designed to assess intake and committed effective dose for these radionuclides. 

However, there may circumstances where it is easier to measure one of the other, 

less radiologically significant, radionuclides and to use this as a “tracer” for the 

mixture. This is feasible when the composition of the mixture is well-known and 

constant. A common example is the use of 241Am as a tracer for plutonium 

isotopes. 

Table 1. Dose Coefficients for the GI Organs due to Inhalation of U-238 and Th-234 

Dose coefficients for inhalation (AMAD= 5um) (Sv/Bq) 

Type M Type S 

Organs U-238 Th-234 U-238 Th-234 

Stomach Wall 5.15E-09 4.56E-10 6.55E-10 4.42E-10 

Small Intestine Wall 5.77E-09 1.07E-09 1.34E-09 1.10E-09 

Upper Large Intestine Wall 1.12E-08 6.17E-09 7.36E-09 6.49E-09 

Lower Large Intestine Wall 2.41E-08 1.75E-08 2.18E-08 1.85E-08 

Colon 1.67E-08 1.10E-08 1.36E-08 1.16E-08 
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This is the case for Th-234, which delivers significant dose in the gastrointestinal tract. Table 1 

illustrates the dose coefficients for gastrointestinal organs due to inhalation of U-238 and 

Th-234. The dose coefficients due to inhalation of Th-234 are very similar to the ones due to 

inhalation of U-238. Therefore, Th-234 inhalation needs to be considered in addition to the 

inhaled U-238 and sequent build up of Th-234 inside the body from the inhaled U-238. 

Dose from internal Pa-234m

The dose contribution due to Pa-234m from the decay of Th-234 in the body also needs to be 

included in the internal dose calculations. While it is true that the Pa-234m outside the body 

only contributes to the external dose, the Pa-234m originating inside the body from Th-234 

decay must be included in the internal dose calculations. 

Finding #19: Incomplete Assessment of Radon Exposure

Table 5-2 of TBD-5 (ORAUT 2005e) describes the potential radionuclide exposure in the 

different buildings of the WSCP. Radon is listed as a source of exposure inside Buildings 101, 

103, 105, 403 and 407. However, the recommended approach in TBD-5 (page 37) to estimate 

radon doses is based on environmental radon concentrations (calculated from source terms) for 

the areas within 100 meters of the assumed release point, the acid recovery plant stack. Using 

this approach requires that several assumptions be made, which results in large uncertainties in 

the dose estimates for workers located in indoor workplaces. 

The data from MCW St. Louis Downtown Site and the St Louis Airport Site in ORAUT-TKBS0005 (ORAUT 2005h) has shown that there is no correlation between outdoor and indoor radon 

concentration. In Table 24 of ORAUT-TKBS-0005, page 209, radon measurements for indoor 

and outdoor 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. 
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Table 2. 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. 

This shows that the approach recommended in TBD-5 is not always claimant favorable. NIOSH 

should propose a more reliable and claimant-favorable approach to assess the radon exposure for 

WSCP. 

Finding #20: Different Solubility Classes Listed for Same Element 

Table 5-6 of TBD-5 (ORAUT 2005e, page 15) provides a list of solubility classes for uranium 

and thorium compounds in some of the buildings at the WSCP. Some of this information is 

summarized below: 

Table 3. Solubility Classes for Uranium and Thorium at WSCP 

Building 103: 

U-234: D=0.20; W=0.50; Y=0.30; 

U-235: D=0.20; W=0.44; Y=0.36; 

U-238: D=0.75; W=0.25. 

Building 108:

U-234: D=0.19; W=0.20; Y=0.61;

U-235: D=0.14; W=0.47; Y=0.39; 

U-238: D=0.19; W=0.20; Y=0.61. 

Buildings 406, 408, 410, 417: 

Th-232: W=0.35; Y=0.65; 

Th-228: W=0.65; Y=0.35. 

Because there were no means of separating isotopes of a given element at the WSCP, the 

chemical properties were the same for all uranium isotopes and the chemical properties were the 
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same for all thorium isotopes. According to ICRP Publication 78 (ICRP 1997), the biokinetic 

behavior is the same for U-234, U-235 and U-238 (see Tables A.10.6, A.10.7 and A.10.8, 

page 127). The same applies for thorium Th-232 and Th-228 (see Tables A.9.8, A.9.9, and 

A.9.10, page 107). 

Although Table 5-6 of TBD-5 (ORAUT 2005e) was taken directly from the reference 

DOE/OR/21548-241 (DOE 2001), it does not appear to be applicable here. In view of the 

operations that took place at the WSCP, TBD-5 (ORAUT 2005e) should provide 

justification/clarification concerning the use of Table 5-6 and the classes of solubility that should 

be assumed in the different workplaces at the WS site. 

Finding #21: Missed Dose and Coworker Data Not Adequately Addressed 

Missed Dose

TBD-5 (ORAUT 2005e) does not address potential internal missed dose, which should be part of 

the TBD for internal dose, especially considering the complexity of the workplace conditions and 

the urinalysis techniques applied at the WS site. The urinalysis was based on a photofluorimetric 

method and reported in units of mg U/liter urine; the isotopic composition of uranium in urine 

samples was unknown. Additionally, the LOD was generally high in the earlier years, which 

could result in significant missed doses. For the dose reconstructor to assign missed dose, the 

TBD needs to provide some information concerning the MDA for given bioassay techniques for 

the important radionuclides of concern at the WS site as a function of time, and specific 

radionuclides to assume, or a claimant-favorable default radionuclide. If the MDA values are 

unknown, the worst-case scenario for a combination of MDA/radionuclide should be provided. 

Coworker Dose

If the dose reconstructor needs to apply internal coworker dose, TBD-5 (ORAUT 2005e) does 

not provide sufficient instructions for the use of Tables 5-8 through Table 5-17, especially in 

view of the problem with cost-center code listings, as described in a previous finding. Most 

internal dose TBDs provide a summary section in the main text or as an appendix with 

recommendations and procedural steps for using coworker data. 

An item of importance that applies to both missed and coworker dose data is the fact that in the 

everyday operations at the WS site, urine samples were not necessarily collected, as stated in 

some of the documents. For example, TBD-5 (ORAUT 2005e, page 17) quotes the following 

from MCW 1965b: 

The routine sampling program seeks to have one or more persons from each 

operational group in the plant sample(d) each week. When a person represents 

his group in the sample, he is asked to give samples on (1) Monday a.m., 

(2) Friday p.m., and (3) Monday a.m. The Monday sample tends to show the 

amount semi-fixed in the body, the Friday sample reflects the daily uptake. The 

sample from each person is analyzed separately and entered in his summary. 
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Each exposed person is scheduled three or more times per year, more frequently 

if there is reason to suspect increased exposure. The rotation of group 

representation tends to show the average level and variation within each plant 

area. Unexposed persons are scheduled less frequently to provide a control base. 

Additionally, a document entitled, Urinary Uranium Program, issued by MCWUD in 1960 

(MCW 1960) provides instructions for waged and salaried personnel: 

1. Wage – Wage employees working with uranium are to be sampled in a series 

of five samples twice a year. As much coverage as possible is desired for 

different types or degrees of exposure; therefore, each series of samples or 

group weeks should contain personnel from as many work areas or crafts as 

possible. Example: All the pipefitters or the Pot Room operators should not 

be scheduled in the same series. 

For the selection of these groups, the place and type of work needs to be 

known. The names and cost centers of the employees may be obtained from 

the IBM wage report. For Maintenance personnel, the information as to 

crafts may be obtained from the Maintenance Office. The shift schedules of 

the Production operators in the Sampling Plant and Refinery may be obtained 

from the Job History Sheets received by the Health Department. 

2. Wage personnel not in contact with uranium are sampled once quarterly, as 

close scheduling is not necessary; therefore, the IBM wage report will suffice 

for selection. 

3. Salary – Salaried personnel are sampled one, two or three times a year; 

therefore, all the salaried personnel are treated as one representative group. 

However, SC&A’s preliminary review of some of the WS site claimant files indicates that, while 

the urine samples were sometimes started on a Friday, they did not necessarily follow a M-F-M 

schedule, and were not generally on a rotating or routine basis. Therefore, when urinalysis data 

is used, either for individual claimants or as a basis for deriving coworker doses, it should be 

used with the caution that it is does not necessarily represent the prescribed sampling schedules 

in the MCW documents. From an initial analysis of WS site claimant files, SC&A did find that, 

while the urinalysis sampling routine was not always as prescribed, most of the claimants’ DOE 

files contained individual urinalysis results by date, as opposed to an average of a number of 

analysis results by week or quarter. 

Secondary Findings

Finding #22: Cost-Center Codes may not be Reliable for Dose Reconstruction 

The use of the cost-centers codes listed on pages 19 and 22–27 of TBD-5 (ORAUT 2005e) are 

not practical, because workers’ DOE files generally do not contain cost-center information; some 
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may contain job titles, or work locations. Additionally, TBD-2 states the following (ORAUT 

2005b, page 20): 

“Beginning in 1954 the (cost center) codes changed about once every 6 months. 

Documentation of changes was made only to the extent that was necessary to 

obtain the money for the UD (Uranium Division) operations from the government 

[Dupree 1983].” Assuming that the practice continued into the WSCP operations 

of 1956 and beyond, using cost center codes to help assess worker dose may not 

be reliable. 

Examples of more useful tables are those in TBD-6 (ORAUT 2005f, pages 17–18). 

It is difficult to analyze or compare the excretion rates for the years 1959–1966 [Tables 5-10 

through 5-17 of TBD-5 (ORAUT 2005e)], because cost-center codes changed. Using cost-center 

codes as this TBD has appears to be an ineffective way of organizing the data. Additionally, 

using cost-center codes to group the data in these tables does not allow the dose reconstructor to 

directly use the solubility information provided in Table 5-6, which is listed by area/building 

numbers. 

The internal dose assessment for WSCP is very complex, because the workers were exposed to 

different uranium compounds (or different classes of solubility), as well as natural, recycled, 

depleted, and EU, and thorium. Additionally, the measurement technique for urinalysis used at 

the WSCP was mainly photofluorimetric, which did not provide sufficient information to have a 

reliable dose assessment when there was a mixture of uranium compounds and uranium isotopes. 

Based on these facts, it would be more appropriate to have the data grouped according to work 

location or job title, such as in TBD-6 (ORAUT 2005f, pages 17–18), to avoid confusion and 

possible incorrect assignment of dose. 

Finding #23: Negative In-vivo Results Do Not Necessarily Indicate Lack of Thorium 

Uptake 

TBD-5 (ORAUT 2005e, page 28) indicates that a portable whole-body counter was set up for invivo thorium measurements in 1966. On page 29, it is states the following: 

 

The overall results showed workers involved in areas 101, 103, 301, 403, 

Maintenance, and Health and Safety, which were principal exposure positions, 

had a more frequent occurrence of ‘trace’ detections. No workers monitored 

showed a ‘positive’ designation. (Ingle 1991) 

Because the LODs for this bioassay technique were generally very high during that period, the 

results of these measurements should not be considered as indicative of a lack of internal 

exposure. Hence, measurements recorded as “negative result” should not be interpreted as the 

workers not being exposed to thorium. These in-vivo measurements were only performed once 

in July 1966; the TBD does not address the issue of workers potentially exposed to thorium in 

early periods and if the thorium and/or decay products would be sufficiently present in the 

workers’ lungs to be detected by this method. Additionally, the TBD did not provide 
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information concerning the MDA for these in-vivo measurements for use in dose reconstruction 

to address missed thorium doses, as well as recommendations for dose reconstruction for 

workers who may have been exposed to thorium, but did not have in-vivo measurements 

performed. Further analysis of these bioassay results may provide upper bounds for thorium 

intake, but most likely they would not provide definite quantitative values. 

A 1965 DOE Annual Health Protection Review of the MCWND, WS site (DOE 1965, pages 8 

and 10 of Weldon Springs Health Protection memorandum) states the following: 

2. Internal Exposure: Bio-assay procedures and action criteria have been given 

detailed consideration previously and no significant change has since 

resulted. Note is made, however, that conventional bio-assay techniques are 

not adequate for monitoring potential thorium exposures as result from 

current MCW production operations. 

E. Thorium pot denitration operations were observed to be poorly contained and 

visibly dusty. Particularly was this noted during a hand scooping transfer 

procedure which was being done outside the hood. Air movement in the 

vicinity was vigorously adverse to contamination control due to a partially 

open outside door. Air line respirators are required for this operation which, 

due to a specification requirement of the “light” oxide material, will not 

permit the use of a more desirable pneumatic transfer procedure. Air 

sampling by the Health and Safety Department indicated average time 

weighted concentrations to be slightly less than the thorium MPC; however, 

the visible dusting observed would suggest that undue confidence may have 

been placed in these data and the procedures requiring respirator use. 

This indicates that thorium operations were of concern, and perhaps not as well 

controlled/monitored as would be desired. 

Finding #24: Enriched Uranium Not Sufficiently Addressed 

TBD-5 (ORAUT 2005e) discusses EU on page 12, where it is stated, “WSCP also processed 

depleted uranium and slightly enriched (up to 1%) uranium as well as natural thorium.” And on 

page 13, where it states, “For slightly enriched uranium, it is reasonable to assume that the 

composition of 1% enriched uranium in the Technical Basis Document for the Fernald 

Environment Management Project – Occupational Internal Dosimetry (ORAU 2004a, Table 5-3) 

is applicable to slightly enriched uranium at WSCP.” In addition, it states, “Although uranium 

with enrichments of less than 1% might have been processed at WSCP, it is claimant-favorable 

to assume 1% enrichment for all slightly enriched uranium at WSCP.” These statements imply 

that if the dose reconstructor uses 1% EU with the composition as listed in the Fernald TBD [and 

reproduced in Table 5-5 of WS site TBD-5 (ORAUT 2005e)], then this is likely an overestimate 

and, therefore, claimant favorable. There are several problems with this assumption: 

• There is no documentation presented that shows that the WS site only received EU from 

Fernald. 
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• There is no supporting evidence that the EU received at the WS site was never >1%. A 

WS document (MCW 1966, page 4) states up to 1.5% enrichment. 

• If the EU was received from Fernald, there is no guarantee that it was always <1% 

enrichment. Fernald’s TBD-5 (ORAUT 2004b, page 9) states the following: 

Late in 1964 the Fernald site provided the first production of 1.95% 235U 

billets for the Hanford Site. During the following production years uranium 

was processed in a variety of enrichments ranging from depleted to as high as 

20%. The quantities of enriched material above 2% was not documented, but 

was qualitatively reported to be small and/or insignificant in total mass. The 

reported highest enrichment level processed in quantity was 2%. 

• SC&A questioned the validity of the assumption that the Fernald site handled <2% 

enrichment in their review of the Fernald site profile (SC&A 2006). 

TBD-5 (ORAUT 2005e, page 35) recommends that the dose constructor use 1% EU for the 

period 1963–1967. However, as outlined above, assuming a maximum enrichment of 1% is not 

supported by the documentation presented. 

3.2.4 External Dose ORAUT-TKBS-0028-6 

Background and Introduction 

The current version of TBD-6 (ORAUT 2005f) covers the operational period 1957–1966, and the 

remediation period 1985–2000. The TBD provides some information concerning dosimetry 

records, badge exchanges, missing entries, calibration, and workplace radiation fields as a 

function of building. Basic coworker gamma and beta dose values as a function of job 

description are provided, along with LOD/exchange tables for calculation of missed dose. As 

with the other TBDs for the WS site, this TBD draws on information/data from other DOE sites, 

such as Fernald, because of the lack of WS site documentation, especially in the area of neutron 

exposure, dosimeter response, and radiation field characterization. Overall, the TBD addresses 

external doses from gamma, neutron, and electron radiation, but SC&A has areas of concern as 

detailed in the findings listed below. 

Primary Findings 

Finding #25: Shallow and Extremity Doses Not Sufficiently Characterized 

Shallow (mainly beta) dose was briefly addressed in TBD-6 (ORAUT 2005f) on pages 12 

(dosimeter quantities, OW, SW, etc.) and on pages 20–23 (compared beta dose from NU, EU, 

and DU). Electron dose is listed as >15 keV in Table 6-10 concerning energy distribution by 

building or area. Extremity monitoring is addressed briefly for the period 1992–1994 on 

page 12. 

As described in a previous finding, there appears that there was no personal contamination or 

egress monitoring at WS during the operations period 1957–1966 to detect contamination on the 

workers after they changed clothes and left the operation areas. Additionally, there is no 
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indication that routine extremity monitoring was performed at WS during this period, or that 

geometry factors were used to correct for the position of the badge versus the radiation source. 

No WS site documents have been located that address the change in film badge response as a 

function of radionuclide exposure, especially to low-energy photons and changes in beta 

energies. Therefore, SC&A has the following areas of concern: 

• No egress monitoring – Unmonitored external and internal doses from lack of personal 

contamination and egress monitoring was previously described. The result of this lack of 

egress monitoring applies to both unmonitored and monitored workers and is especially 

important for shallow dose exposures. 

• Badge vs. exposure geometry factors – The problems associated with handling uranium 

material [contact work as stated on page 20 of TBD-6 (ORAUT 2005f)] close to the 

body/hands and having the dosimeter badge located on the chest area was not addressed 

in TBD-6 or other WS site 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 

office memo (MCW 1959) 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. A TIB needs to be developed for the WS 

site to correct for this underestimate of dose, such as OCAS-TIB-0013 (NIOSH 2005) 

was for the MCW Destrahan Street site. This is especially important for beta exposures. 

• Total shallow dose – According to page 16 of TBD-6 (ORAUT 2005f), the dosimeters at 

the WS site were calibrated using radium photon and uranium beta sources. This is 

standard practice for uranium processing facilities. However, the WS site also handled 

other radionuclides, as described in TBD-6 and other WS site documents; these included 

Th-232 and RU with their associated decay products. Some of these radionuclides have 

different beta energies than uranium. Additionally, TBD-6 does not address shallow dose 

from low-energy photons, which may have been more predominate from these 

radionuclides as compared to uranium. TBD-6 briefly discusses mixed beta-gamma 

exposures on page 11 and states that they were determined by subtraction; it is assumed 

that this means that the reading from the portion of the film behind the cadmium shield 

(called SW) was subtracted from the reading of the film without cadmium shielding 

(called OW), as indicated in Table 6-2 on page 12. This is not a valid procedure, unless 

the beta-to-gamma ratio is known and remains constant, because beta and gamma 

radiation have different darkening effects per unit dose. The response of film to gamma 

radiation is very energy-dependent because of the photoelectric effect, whereas beta 

interactions are not subject to this dependence. Shallow doses from both beta and lowenergy photons concerning calibration versus workplace radiation fields as a function of 

location and time needs further investigation and more adequately addressed in this TBD. 
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Finding #26: Badging Policy not Consistent 

TBD-6 (ORAUT 2005f) provides a reasonable amount of detail concerning the badge exchange 

cycles, such as on page 11 and elsewhere in the TBD. However, insufficient information is 

provided concerning the badging policies at the WS site. TBD-6 does not provide a consistent 

outline of what workers were badged and when. Table 6-4, page 14, states “All MCW Uranium 

Division wage (hourly) personnel are assigned permanent film badges.” (Emphasis added.) 

However, on page 14 of Section 6.2.2.4, it states, “’Office females’ were not routinely assigned 

film badges,” and on page 13, it states that female workers were not routinely monitored, 

especially in the early days. Table 6-5 of TBD-6 lists several facilities that were considered 

“non-badged areas.” However, Section 2.5.1.1 of TBD-2 (ORAUT 2005b, page 29) states that 

“According to Mason (1955) health protection program document, each employee except office 

females wears (a) combination film badge-security badge” (emphasis added). This raises the 

question of what badging criteria were actually used in practice, and if workers who were not 

considered at the time to be exposed to radiation were potentially exposed, but not monitored 

because of being in a pre-defined category. The lack of a consistent and documented badging 

policy may negatively impact dose reconstruction, because the dose reconstructor could assign 

an unbadged worker only external environmental dose, when the worker should have been 

assigned coworker external dose. Additionally, the validity of a coworker database depends on 

how well it represents a cross-section of the workers; to determine this, a knowledge of why, 

when, and where workers were badged at the WS site is necessary. 

Finding #27: Lack of Sufficient Coworker Data Development for External Dose 

Section 6.2.3 of TBD-6 (ORAUT 2005f, page 16) mentions that annual average gamma and beta 

exposures were calculated. The information for 10 categories of worker is listed in Table 6-8 

and graphically displayed in Figures 6-4 and 6-5 on pages 18 and 19. However, the TBD does 

not provide any information concerning the details/application of this information, such as the 

following: 

• The number of data points for each of the dose entries; i.e., how many readings were 

used to calculate the dose value of 110 mrem for Engineers in 1957 

• The percent of workers who were monitored 

• The range of readings within a given data point; i.e., what were the minimum and 

maximum values for Engineers for 1957 

• The 50th and 95th percentile values for each entry. 

• It should be stated whether the reading from an occupationally unexposed (background) 

film was subtracted from the doses before the average values were calculated, or if it was 

not 

• It should be stated whether zeros were include in the dose readings used to calculate the 

listed values 

• It should be stated whether these values were derived from dose values greater than some 

threshold (i.e., LOD, 1⁄2 LOD, 50 mrem, etc.) 
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• It should be stated if any unusual outliers were excluded/included in the data 

The data presented is a good start in creating a coworker database, but in order to determine its 

validity and Representativeness, there needs to be additional work performed on the data as 

outlined above. Additionally, to be useful to the dose reconstructor, there needs to be 

recommendations for use of the data, such as a summary appendix with specific dose assignment 

recommendations, numerical values, and tables, as contained in many other site profiles. 

Secondary Finding 

Finding #28: Lack of Documentation and Details for Neutron Doses 

Table 6-3 of TBD-6 (ORAUT 2005f, page 13) states, “Estimate neutron dose as 10% of the 

reported gamma dose in facilities containing UF4 and UF6.” Table 6-4 on page 14 states that 

“All MCW Uranium Division personnel who work directly with enriched uranium materials are 

assigned special neutron dosimeter badges, which are worn in conjunction with the regular film 

badges.” However, the results of this badging (presumable NTA film) were not discussed and no 

data is presented, except to mention in Section 6.2.4.2 (page 19) that no neutrons were 

anticipated or measured with the WSCP film badge. TBD-6 then switches to the use of 

Fernald’s TBD-6 (ORAU 2004c) neutron-to-photon ratio (n/p) value of 0.1, with the statement 

that the use of the Fernald analysis is appropriate and will be used in this TBD. The Fernald 

TBD-6 (ORAU 2004c, pages 18–20) describes the process of deriving the n/p value of 0.10; this 

consisted of measuring the neutron doses from UF4 (green salt) canisters in 1995 and then 

measuring the photon dose from 56 drums of UF4 in 2001. The n/p geometric mean value was 

0.10, with an upper 95th percentile of 0.23, and with a geometric standard deviation of 1.71. 

There are a number of problems with assuming that the n/p value of 0.1 from the Fernald site can 

be used at the WS site: 

• There are no indications that the “containers” used in 1995 and the “drums” used in 2001 

are the same geometry. 

• There are no indications that the UF4 in the containers used in the 1995 measurements 

and the UF4 in the drums used in the 2001 measurements are of the same radioisotope 

composition and concentrations to create similar radiation fields for measurements taken 

6 years apart. 

• There is no indication that the matrix material, which would affect the self-shielding of 

the emitted radiation, is the same in both the 1995 and the 2001 measurements. 

• There is no analysis to demonstrate that the radiation fields created by the materials in the 

containers or drums used at the Fernald site reasonably duplicate the radiation fields at 

the WS site, to include such variables as radioisotope composition, concentrations, matrix 

materials, and geometry. 

The methodology to derive the n/p value of 0.1 at Fernald is questionable, and the application of 

this n/p value to the WS site is not technically supported in the TBD. 
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Additionally, the TBD needs to provide information to assist the dose reconstructor in 

determining when to assign neutron dose to workers. Information such as job titles, where and 

when UF4 and UF6 materials were present to create potential neutron exposures, etc., would 

assist the dose reconstructor in determining when to assign neutron dose. 

SC&A has not found any neutron doses recorded or columns labeled for entry of neutron doses 

in the Center for Epidemiological Research (CER) or DOE databases for neutron doses in the 

claimant files analyzed to date. From the information contained in the TBD, it cannot be 

determined if the neutron film badges were issued or read, what the results were, and if they 

were recorded in the workers’ files. 
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4.0 OVERALL ADEQUACY OF THE SITE PROFILE AS A BASIS FOR 

DOSE RECONSTRUCTION 

The SC&A procedures call for both a “vertical” assessment of a site profile for purposes of 

evaluating specific issues of adequacy and completeness, as well as a “horizontal” assessment 

pertaining to how the profile satisfies its intended purpose and scope. This section addresses the 

latter objective in a summary manner by evaluation of (1) how, and to what extent, the site 

profile satisfies the five objectives defined by the Advisory Board for ascertaining adequacy; 

(2) the usability of the site profile for its intended purpose (i.e., to provide a generalized technical 

resource for the dose reconstructor when individual dose records are unavailable); and 

(3) generic technical or policy issues that transcend any single site profile that need to be 

addressed by the Advisory Board and NIOSH. 

4.1 SATISFYING THE FIVE OBJECTIVES 

The completeness, accuracy, and adequacy of data (to include data to be used for monitored 

workers’ individual dose reconstructions and data to be used in deriving coworker database for 

unmonitored workers) should be validated to demonstrate its usefulness. SC&A has performed 

extensive document searches and found over 300 MCW/WS site documents available on the 

O-Drive plus many other documents located at the various DOE document storage/retrieval 

centers, as well as information available at the Weldon Spring Interpretive Center, located on the 

original WSCP site. SC&A also reviewed approximately 30 of the WS site claims to assess the 

information available in the individual energy employee’s dose records and their applicability to 

dose reconstruction and coworker databases. SC&A also conducted several days of onsite 

interviews with former WS site workers to obtain information concerning working conditions 

and exposure potentials that may impact the completeness and usefulness of dose records. The 

following is a summary of SC&A’s evaluation of the present resources available (TBDs, dose 

records, site documents, etc.) to the dose reconstructor for reconstruction of dose to WS site 

workers with reasonable completeness and accuracy. 

4.1.1 Objective 1: Completeness of Data Sources 

During its review of the WS site TBDs, SC&A’s found that NIOSH did not sufficiently address 

the completeness of the dose records for the workers at the WS site for both internal and external 

doses. For example, the WS site TBDs do not explicitly state when DOE employees and/or DOE 

contractors were no longer at the WS site after it stopped operations in December of 1966. It has 

not been determined if DOE employees and/or contractors were present or involved during 

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

at the WSCP, during the 1970–1984 monitoring and maintenance period, or during 1983–1984 

when there were efforts to remediate leaks at the WSRP. If DOE contract personnel were 

present at the WS site soon after the shutdown in December 1966, they could have been exposed 

to numerous radionuclides during decommissioning, clean-out, and revamping the facility for a 

completely different use. This could have lead 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 and/or recorded, or grossly underestimated. Therefore, the present dose records may 
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not be complete if workers were exposed after the operational period and not properly 

monitored. The issue of legal ownership of the property (and liability) as a function of time 

needs to be determine through federal/state/local records to determine if there should be dose 

records available and dose reconstruction performed for any workers during the time period 

1967–1984. 

The WS TBDs do not sufficiently address accidents or incidents at the WS site, or the apparent 

lack of their documentation being readily available. Accidents and incidents that could 

potentially release material to the operational areas and to unmonitored workers onsite are 

important at WS, because the radiological hazards may not have been fully recognized, 

investigated, or documented at the time of occurrence. This could have lead to exposures that 

were not monitored and do not appear in the energy employee’s records. 

The WS TBDs do not address the issue of whether the dose records for the WS workers contain 

the complete dose records for the workers to allow for reasonable dose reconstructions without 

excessive extrapolation or use of other data. SC&A could not find that an analysis of the 

completeness of the dose records and their representativeness of the worker population has been 

performed. 

4.1.2 Objective 2: Technical Accuracy 

SC&A finds that the existing TBDs do not sufficiently address the accuracy of the dose records 

for the WS site workers. For example, the accuracy of shallow dose measurements are very 

much affected by geometry factors (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). The external dose TBD (ORAUT 2005f) did not 

address these geometry factors for the WS site, nor did it include extremity monitoring or the 

lack of it during the operational period. Total shallow dose consists of low-energy photons plus 

beta radiation; the film badge response changes (and therefore, its accuracy) when the energies 

or ratios of the photons to betas changes. The ability of the film badges used at the WS site to 

accurately record the total shallow dose was not addressed in the TBDs. The accuracy of 

neutron dose assignment (TBD-6 recommended using an n/p value of 0.1, derived from the 

Fernald site, to assign neutron dose to workers who may have been exposed to EU) was not 

verified or sufficiently substantiated in the TBD. 

The internal dose TBD (ORAUT 2005e) does not fully address the problem of radioisotopes 

other than uranium that may have been present in the workers’ intake, but not analyzed for in the 

urinalysis. According to the workers’ dose records reviewed to date, there were no analyses 

performed for any element beside uranium, except some workers had an inconclusive one-time 

thorium chest count in July 1966. These other radioisotopes were addressed in the WS site 

profile by extrapolation from other DOE sites; the accuracy of this method has not been verified. 

The WS TBDs do not address the issue of whether the dose records for the WS workers are 

sufficiently accurate to perform dose reconstructions. SC&A’s preliminary review of the WS 

site worker claim files indicate that the summary sheets and later data sheets generally agree with 

the dose values listed on the copies of the original data card, worksheets, etc. (some of the 
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originals were handwritten and some were typed). Additionally, the CER supplemental dose 

database, which accompanies some of the workers’ files, appears to contain a fairly accurate 

representation of the original data, and is listed in a consistent format. However, this was a very 

limited qualitative review of a few cases by SC&A. 

4.1.3 Objective 3: Adequacy of Data 

The lack of WS site-specific data is evident in the WS site profile TBDs because in many 

situations (environmental, internal, and external), the authors of the TBDs had to revert to use of 

genetic dose reconstruction documents (i.e., for occupational medical), other DOE site 

data/TBDs (such as Fernald), or less-than-complete WS site data (such as parameter instead of 

work area data) for the operational (1956–1966) and maintenance (1967–1984) periods at the 

WS site. As previously pointed out by SC&A, the lack of adequate and accurate radiological 

health documentation and data is the main issue concerning claimant-favorable dose 

reconstruction for former WS site workers. The three main areas where the adequacy of data is 

of concern are environmental, internal, and external doses, as outlined below. 

The TBD used one serial of measurements (decontaminating 5-ton hoppers) and site parameter 

measurements to determine contributing intakes to non-bioassayed workers during 1957–1967. 

The hopper dust monitoring experiment was measurements performed on one day under one 

particular condition, and the parameter measurements contributed very little (<1%) to the final 

results. This limited (in space, operations, and time) airborne/intake data is not sufficient to 

construct an adequate environmental intake dose database for unmonitored workers at the WS 

complex, especially considering that a sizable fraction of the work force was not bioassayed on a 

routine basis during this period. 

The TBD does not address potentially missed internal doses, which should be part of a TBD for 

internal dose. The LODs were generally high in the earlier years, which could result in 

significant missed doses. For the dose reconstructor to assign missed dose, the TBD needs to 

provide some information concerning the MDA for given bioassay techniques for the important 

radionuclides of concern at the WS site as a function of time. Additionally, the TBD provides 

some coworker internal dose information, but does not provide sufficient instructions for its use. 

Most internal dose TBDs provide a summary section in the main text, or as an appendix, with 

recommendations and procedural steps for using coworker data. To have adequate data for 

internal dose reconstruction, missed dose and coworker dose data must be considered along with 

recorded dose. 

The external TBD (ORAUT 2005f) does not provide sufficient and/or consistent information 

concerning the badging policies at the WS site in order to evaluate the adequacy of the workers’ 

dose records. Therefore, it has not been determined what badging criteria were actually used in 

practice, and if workers who were not considered at the time to be exposed to radiation were 

potentially exposed, but not monitored because of being in a pre-defined category. The lack of a 

consistent and documented badging policy may have impacted the adequacy of the dose records 

necessary for dose reconstruction. 
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TBD-6 (ORAUT 2005f) provides annual average gamma and beta exposures. However, the 

TBD does not provide any information concerning the details/application of this information, 

such as the number of data points for each entry, percent of workers badged, the range of 

readings, if background was subtracted, if zeroes or outliers were included, if a threshold dose 

was used, etc. The data presented is a good start in creating a coworker database, but in order to 

determine its validity and Representativeness, there needs to be additional work performed on 

the data, as mentioned above. Plus, as for internal coworker data, some guidance/limitations 

concerning the data in a summary form would be appropriate. 

The WS TBDs do not specifically address the issue of whether there are adequate dose records 

available for WS site workers to perform reasonable dose reconstruction for individual workers, 

or to create a technically sound coworker database for both external and internal dose for 

unmonitored, or under-monitored, workers. One of the first areas that should be evaluated when 

a site profile is being performed is to assess the adequacy, accuracy, and representativeness of 

the recorded dose database for internal and external dose reconstruction. This is especially true 

for a location such as the WS site because, by the nature of its operations, a significant portion of 

the worker population were possibly not monitored. If there were large portions of the work 

force that were not monitored, and/or there are excessive gaps or inconsistency in the recorded 

data of individual workers, then this indicates a problem for individual dose reconstruction, as 

well as difficulties in creating a reliable coworker database for unmonitored/under-monitored 

workers. If a solid recorded dose database is found, then this is an indication that there is a basis 

for technically sound dose reconstructions, subject to the verification of the accuracy of the 

monitoring methods (external badging, internal bioassay techniques, etc.). 

SC&A’s preliminary review of several of the WS site workers’ dose records indicate that for the 

workers that were monitored during a given time period, there is a reasonable amount of 

recorded external dose data during that time period. However, this was a very limited 

qualitative review of a few cases, and does not reflect if there were other periods of time when a 

given worker should have been monitored and was not, or if there were other workers that should 

have been monitored but were not. Internal dose records are more difficult to evaluate, because 

it was not a policy at the WS site to continuously bioassay any worker; only periodically perform 

a Monday-Friday-Monday (M-F-M) urinalyses for uranium by means of a grab sample (as 

opposed to a complete 24-hour voiding) of a few workers. This sampling program was meant to 

provide representative samples for each major group of workers. SC&A did find that for the 

claims reviewed, generally individual samples and analysis dates were posted, not just weekly, 

quarterly, or annual average values. However, there did not appear to be a constant M-F-M urine 

sample collection sequence, or repeatable pattern in a given worker’s bioassay data in the 

claimant records that SC&A reviewed. Additionally, there were no bioassay data for any 

radioisotope other than the element uranium (and some inconclusive thorium in-vivo counts). It 

should be emphasized that, because this was a site profile review and not an SEC evaluation 

review, SC&A only performed a very limited qualitative review of the claimants’ DOE records 

to obtain an indication of the contents of the files. 

In summary, there has been insufficient analysis of the recorded internal and external dose data 

to determine the percent of workers who were monitored annually and the representativeness of 
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that data for the worker population at the WS site through the years, and therefore, the adequacy 

of the recorded and/or coworker dose data. 

4.1.4 Objective 4: Consistency among Site Profiles 

When compared to other site profiles, SC&A’s review of the WS site profile TBDs (ORAUT 

2005a–f) did not find major inconsistencies that would significantly impact dose reconstruction 

or create claimant-unfavorable situations. In reviewing the WS site TBDs, SC&A did note that 

surrogate information/data was used more frequently than normally used in other site profiles. 

The WS site TBDs went beyond comparing the general operations and mission of the WS site 

with other sites, to actually using some of the recorded/derived data from the Fernald site. 

Additionally, the WS site TBDs did not provide summary sections concerning the 

application/limitations/instructions for use of the coworker dose data presented in the TBDs as 

most site profiles do. 

4.1.5 Objective 5: Regulatory Compliance 

No regulatory compliance issues were identified by SC&A in the WS site TBDs. 

4.2 USABILITY OF SITE PROFILE FOR INTENDED PURPOSES 

Because the purpose of a site profile is to support the dose reconstruction process, it is critical 

that the site profile assumptions, analytic approaches, and procedural directions be clear, 

accurate, complete, and auditable (i.e., sufficiently documented). The WS site TBDs generally 

provided some method of assessing worker’s internal, external, occupational medical dose, and 

environmental dose; however, SC&A has some concerns in the use of these TBDs for dose 

reconstruction. 

4.2.1 Fernald Site Data Applied to Weldon Spring Workers 

While NIOSH attempted to use WS site information and data to the extent it was available, 

NIOSH also made extensive use of Fernald site data and extrapolated it to WS site workers. The 

assumptions necessary to equate Fernald site information/data to WS site workers was not 

always sufficiently supported. Therefore, SC&A questions whether some of the data and 

recommendations in the present WS site TBDs are usable for WS site workers. 

4.2.2 Incomplete/Incorrect Information 

In several places in the WS site TBDs, complete information/data is not provided for the dose 

reconstructor. For example, the method used at the WS site to determine shallow dose is not 

sufficiently addressed, and Table 6-2 on page 12 of TBD-6 (ORAUT 2005f) is not complete. 

Additionally, cost-center codes are not reliable categories to use to assess uranium urine data as 

used in TBD-5 (ORAUT 2005e). Different solubility classes are listed for different isotopes of 

the same element in Table 5-6 of TBD-5 (ORAUT 2005e), but the WS site could have had only 

one type of solubility for all isotopes of a given element in a given process or building. SC&A 

found that TBD-5 (ORAUT 2005e) failed to include some decay components of the uranium 

decay chain, and that the assessment of radon exposure was incomplete. 
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Health for factual accuracy or applicability within the requirements of 42 CFR 82. 

4.2.3 Incomplete Dose Reconstruction Recommendations 

TBD-5 (ORAUT 2005e) provides some coworker internal dose information, but does not 

provide sufficient instructions for its use. Most internal dose TBDs provide a summary section 

in the main text or as an appendix with recommendations and procedural steps for using 

coworker data. TBD-6 (ORAUR 2005f) provides annual average gamma and beta exposures. 

However, the TBD does not provide any information concerning the details/application of this 

information, such as the number of data points for each entry, percent of workers monitored, the 

range of readings, if background was subtracted, if zeroes or outliers were included, if a 

threshold dose was used, etc. The data presented is a good start in creating a coworker database, 

but in order to determine its validity, there needs to be additional work performed on the data (as 

mentioned above), as well as determining the representativeness of the data for the entire worker 

population. In addition, some guidance/limitations concerning the use of the data in a summary 

form would be appropriate for both internal and external coworker data. 

4.2.4 Lack of Defined Monitoring and X-ray Exam Criteria 

The WS site TBDs does not inform the dose reconstructor of a documented badging/bioassay 

policy and potential x-ray exam exposures in a consistence manner. The dose reconstructor 

cannot be reasonably certain whether an unmonitored worker should have been badged and/or 

bioassayed, and therefore, assigned a coworker dose, or if an environmental dose assignment is 

more appropriate. Likewise, the frequency and types of x-ray exams are not sufficiently defined 

to allow the dose reconstructors to assign consistence occupational medical doses. 

4.3 UNRESOLVED POLICY OR GENERIC TECHNICAL ISSUES 

A number of issues identified in the WS site TBD review represent potential generic policy 

issues that transcend other individual site profiles. Issues raised in this review that are common 

to other DOE/contractor site investigations include a lack of recorded data analysis for 

adequacy/representativeness, inadequate documentation of badging policy, lack of sufficient 

environmental data for onsite unmonitored workers, insufficient knowledge/documentation of 

source terms and radiation fields, lack of geometry factors for beta and low-energy photon doses, 

and lack of adequately developed (or insufficient data for) coworker internal and external dose 

development. As with many other DOE sites, the WS site also lacks documentation concerning 

accidents, incidence, and episodic releases that would have potential radiological consequences, 

especially in the operational years. Additionally, the lack of information concerning 

occupational medical procedures, equipment, types of exams (PA/LAT, PFG, lumbar), frequency 

of exams for different job titles, etc., are prevalent for the WS site and obvious in TBD-3 

(ORAUT 2005c), as it is for many of the earlier DOE sites. A common problem that the WS site 

has with other uranium processing facilities in the early days is that uranium was mostly 

controlled using chemical toxicity levels, rather than being viewed as a radiological hazard. This 

lead to some working conditions and lack of monitoring that would not be acceptable by present 

standards. These issues are discussed in detail as findings in Section 3 of this report.
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5.0 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. 

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 (U.S. Department of Energy) 1965. Review of Mallinckrodt Chemical Works October 

1965, Oak Ridge Operations Office, Oak Ridge, Tennessee, September. Ref ID #11806. 

DOE (U.S. Department of Energy) 1985. The Report of the Joint Task Force on Uranium 

Recycle Materials Processing, Report No. DOE/OR-859, Oak Ridge Operations Office, Oak 

Ridge, Tennessee, September. Ref ID #26854 

DOE (U.S. Department of Energy) 2001. Internal Dosimetry Program Technical Basis Manual: 

Weldon Spring Site Remedial Action Project, Rev. 7, DOE/OR/21548-241, Oak Ridge 

Operations Office, Oak Ridge, Tennessee, December, 2001. Ref ID #32724.

Dupree, E.A., 1983. “Visit to MCW Corporate Headquarters,” memorandum to file, October 25, 

Oak Ridge Associated Universities, Oak Ridge, Tennessee. 

Eberline (Eberline, Inc.) 1983. Weldon Spring, E2457, Sludge Analysis, 18 August 1983. 

Ref ID #14778. 

Holt, D., 1960. MCW (Mallinckrodt Chemical Works) office letter, Decontamination of Fiveton Portable Hoppers for Shipment, August 8, 1960, Health and Safety Department, Uranium 

Division, Weldon Spring, Missouri. Ref ID 14974) 

ICRP 1982. Protection of the Patient in Diagnostic Radiology, Annals of the International 

Commission on Radiological Protection, Publication 34, Vol. 9/2, Pergamon Press, Oxford, 

England.

ICRP 1996. Conversion Coefficients for Use in Radiological Protection Against External 

Radiation, International Commission on Radiological Protection Publication 74, Pergamon 

Press, Oxford, England.

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

on Radiological Protection Publication 78. Pergamon Press, Oxford. 

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

MCW (Mallinckrodt Chemical Works) 1960. Office letter, Urinary Uranium Program, Health 

and Safety Department, Uranium Division, Weldon Spring, Missouri, January 1, 1960. Ref ID 

14964. 

MCW (Mallinckrodt Chemical Works) 1961. Summary Report: Chemical Operator Burned 

With Molten Uranium Salt Solution, Health and Safety Department, Uranium Division, Weldon 

Spring, Missouri, June 1, 1961. 

MCW (Mallinckrodt Chemical Works) 1965a. Office letter, Thorium Operations at MCW, 

Health and Safety Department, Uranium Division, Weldon Spring, Missouri, November 2, 1965. 

(Ref ID #11799). 

MCW (Mallinckrodt Chemical Works) 1965b. Summary of Health Protection Practices, Health 

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

14998. 

MCW (Mallinckrodt Chemical Works) 1983. Radioactive Wastes in Pits 1, 2, 3, & 4, Health and 

Safety Department, Uranium Division, Weldon Spring, Missouri, Revised 1965. Ref ID 14998. 

MCW (Mallinckrodt Chemical Works) 1966. Summaries of Dust Concentrations at Production 

Jobs, Health and Safety Department, Uranium Division, Weldon Spring, Missouri. Ref ID 

15000. 

NIOSH (National Institutes for Occupational Safety and Health) 2002. External Dose 

Reconstruction Implementation Guideline, OCAS-IG-001, NIOSH Office of Compensation 

Analysis and Support, Rev. 1, August, 2002.

NIOSH (National Institutes for Occupational Safety and Health) 2004. Advisory Board on Dose 

Reconstruction, Task 1 - Site Profile Reviews, Subtask 1 - Site Profile Review Procedures, May 

13, 2004. 

NIOSH (National Institutes for Occupational Safety and Health) 2005. Special External Dose 

Reconstruction Considerations for Mallinckrodt Workers, OCAS-TIB-013, Rev. 0, Office of 

Compensation Analysis and Support. October 26, 2005.

ORAUT (Oak Ridge Associated Universities Team) 2004a. Technical Basis Document for the 

Fernald Environmental Management Project – Occupational Environmental Dose, ORAUTTKBS-0017-4, Rev. 00, April 2004. 

ORAUT (Oak Ridge Associated Universities Team) 2004b. Technical Basis Document for the 

Fernald Environmental Management Project – Occupational Internal Dose, ORAUT-TKBS0017-5, Rev. 00, May 2004. 

ORAUT (Oak Ridge Associated Universities Team) 2004c. Technical Basis Document for the 

Fernald Environmental Management Project – Occupational External Dose, ORAUT-TKBS0017-6, Rev. 00, April 2004. 
Effective Date: 

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

ORAUT (Oak Ridge Associated Universities Team) 2005a. Weldon Spring Plant – Introduction, 

ORAUT-TKBS-0028-1, C. Little and R. Meyer, Rev. 00, 28 June 2005a. 

ORAUT (Oak Ridge Associated Universities Team) 2005b. Weldon Spring Plant – Site 

Description, ORAUT-TKBS-0028-2, C. Little and L. McDowell-Boyer, Rev. 00, 24 June 2005. 

ORAUT (Oak Ridge Associated Universities Team) 2005c. Weldon Spring Plant – 

Occupational Medical Dose, ORAUT-TKBS-0028-3, T. Lopez and J. Furman, Rev. 00, 24 June 

2005c. 

ORAUT (Oak Ridge Associated Universities Team) 2005d. Weldon Spring Plant – 

Occupational Environmental Dose, ORAUT-TKBS-0028-4, L. McDowell-Boyer and C. Little, 

Rev. 00, 28 June 2005. 

ORAUT (Oak Ridge Associated Universities Team) 2005e. Weldon Spring Plant – 

Occupational Internal Dose, ORAUT-TKBS-0028-5, Janet A. Johnson and Roger B. Falk, Rev. 

00, 28 June 2005. 

ORAUT (Oak Ridge Associated Universities Team) 2005f. Weldon Spring Plant – 

Occupational External Dosimetry, ORAUT-TKBS-0028-6, J. Langsted and C. Little, Rev. 00, 24 

June 2005. 

ORAUT (Oak Ridge Associated Universities), 2005g, Technical Information Bulletin: Dose 

Reconstruction from Occupationally Related Diagnostic X-ray Procedures, ORAUT-OTIB0006, Rev. 03, Oak Ridge, Tennessee. 19 April 2005. 

ORAUT (Oak Ridge Associated Universities Team) 2005h. 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, March 2005. 

ORAUT (Oak Ridge Associated Universities Team) 2008. Weldon Spring Plant – Introduction, 

ORAUT-TKBS-0028-1, C. Little and R. Meyer, Rev. 00 PC-1, 20 June 2008. 

SC&A 2006. Review of the NIOSH Site Profile for the Fernald Environmental Management 

Project (Feed Materials Production Center), SCA-TR-TASK1-0010, November 2006. 

Stradling G., Hodgson A., Fell T., Phipps A., and Etherington G. Thorium Nitrate and Dioxide: 

Exposure Limits and Assessment of Intake and Dose after Inhalation, National Radiological 

Protection Board, Oxon OX11 ORQ, NRPB-W57, May 2004. 

Weldon Spring Site, 1983, Table 2-8, Radioactive Wastes in Pits 1, 2, 3, & 4, page 26, 1317B, 

unknown author, January 21, 1983. Ref ID #14777. 
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ATTACHMENT 1: NIOSH TECHNICAL DOCUMENTS CONSIDERED 

DURING THE REVIEW PROCESS 

Technical Basis Documents 

Oak Ridge Associated Universities Team (ORAUT), Technical Basis Document for the Fernald 

Environmental Management Project – Occupational Environmental Dose, ORAUT-TKBS0017-4, Rev. 00, April 2004. 

Oak Ridge Associated Universities Team (ORAUT), Technical Basis Document for the Fernald 

Environmental Management Project – Occupational Internal Dose, ORAUT-TKBS-0017-5, 

Rev. 00, May 2004. 

Oak Ridge Associated Universities Team (ORAUT), Technical Basis Document for the Fernald 

Environmental Management Project – Occupational External Dose, ORAUT-TKBS-0017-6, 

Rev. 00, April 2004. 

Oak Ridge Associated Universities Team (ORAUT), Weldon Spring Plant – Introduction, 

ORAUT-TKBS-0028-1, C. Little and R. Meyer, Rev. 00, June 28, 2005. 

Oak Ridge Associated Universities Team (ORAUT), Weldon Spring Plant – Introduction, 

ORAUT-TKBS-0028-1, C. Little and R. Meyer, Rev. 00 PC-1, June 20, 2008. 

Oak Ridge Associated Universities Team (ORAUT), Weldon Spring Plant – Site Description, 

ORAUT-TKBS-0028-2, C. Little and L. McDowell-Boyer, Rev. 00, June 24, 2005. 

Oak Ridge Associated Universities Team (ORAUT), Weldon Spring Plant – Occupational 

Medical Dose, ORAUT-TKBS-0028-3, T. Lopez and J. Furman, Rev. 00, June 24, 2005. 

Oak Ridge Associated Universities Team (ORAUT), Weldon Spring Plant – Occupational 

Environmental Dose, ORAUT-TKBS-0028-4, L. McDowell-Boyer and C. Little, Rev. 00, June 

28, 2005. 

Oak Ridge Associated Universities Team (ORAUT), Weldon Spring Plant – Occupational 

Internal Dose, ORAUT-TKBS-0028-5, Janet A. Johnson and Roger B. Falk, Rev. 00, June 28, 

2005. 

Oak Ridge Associated Universities Team (ORAUT), Weldon Spring Plant – Occupational 

External Dosimetry, ORAUT-TKBS-0028-6, J. Langsted and C. Little, Rev. 00, June 24, 2005. 

Oak Ridge Associated Universities Team (ORAUT), 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, Rev 01, March 2005. 
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Health for factual accuracy or applicability within the requirements of 42 CFR 82. 

Technical Support Documents 

National Institutes of Occupational Safety and Health (NIOSH) Office of Compensation 

Analysis and Support, External Dose Reconstruction Implementation Guideline, OCAS-IG-001, 

Rev. 1, August 2002.

National Institutes of Occupational Safety and Health (NIOSH) - Advisory Board on Dose 

Reconstruction, Task 1 - Site Profile Reviews, Subtask 1 - Site Profile Review Procedures, 

May 13, 2004. 

National Institutes of Occupational Safety and Health (NIOSH) Office of Compensation 

Analysis and Support, Special External Dose Reconstruction Considerations for Mallinckrodt 

Workers, OCAS-TIB-013, Rev. 0, October 26, 2005.

ORAU (Oak Ridge Associated Universities), 2005, Technical Information Bulletin: Dose 

Reconstruction from Occupationally Related Diagnostic X-ray Procedures, ORAUT-OTIB0006, Rev. 03, Oak Ridge, Tennessee. April 19, 2005. 
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ATTACHMENT 2: SITE EXPERT INTERVIEW SUMMARY 

INTRODUCTION 

In accordance with its mandate under the Energy Employee Occupational Illness Compensation 

Program Act (EEOICPA), the Advisory Board on Radiation and Worker Health (Advisory 

Board) requested that SC&A review the Weldon Spring site profile (ORAUT 2005a, ORAUT 

2005b, ORAUT 2005c, ORAUT 2005d, ORAUT 2005e, and ORAUT 2005f). SC&A was 

requested by the Advisory Board to assist in these investigations. A large number of interviews 

were concerned with obtaining first-hand information regarding the nature of the day-to-day 

working environment of the various categories of personnel at the site. This report summarizes 

the results of the interviews performed to date by SC&A. 

A total of 20 interviews were conducted with former Weldon Spring workers and other site 

experts. Workers covered the time period from construction to remediation. Dr. Ron Buchanan 

and Ms. Kathryn Robertson-DeMers conducted interviews from April 28–30, 2009, in the St. 

Louis, Missouri, area. One subsequent interview was conducted in Oak Ridge, Tennessee, and 

one interview was conducted by telephone. The purpose of these interviews was to hear firsthand accounts of past radiological control and personnel monitoring practices, and to better 

understand how operations and safety programs were implemented at the site over time. 

Interviewees were identified through available site reports, public meeting transcripts, local 

advocates, other interviewees, and previous interviews conducted for the Mallinckrodt Destrehan 

Street Plant. 

Collectively, those interviewed worked at the Weldon Spring (WS) Plant from 1956–1966. 

Employees interviewed worked at the Administrative Building, the Digestion and Denitrification 

Building, the Extraction Building, the Metals Building, the Green Salt Building, the Pilot Plant, 

the Maintenance and Stores Building, the Laboratory, and the Raffinate Pits. Some individuals 

worked throughout WS and also transported materials to other Mallinckrodt Chemical Works 

(MCW) facilities, such as the Destrehan plant and the Latty Avenue facility. A number of 

interviewees transferred from the MCW Destrehan plant when WS was built. The worker 

categories represented by the interviewees include the following: 

• Administrative 

• Computer Operations 

• Construction 

• Document Control 

• Environmental Advocate 

• Environmental Restoration 

• Health and Safety (H&S) 

• Operations 

• Machine Operations 

• Maintenance and Crafts 

• Manufacturing 

• Transportation 
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SC&A explained that the interviews were being conducted on behalf of the Advisory Board as 

part of their investigations of NIOSH’s site profile. Participants were told that the interviews 

were unclassified, and that they should not disclose any classified information. Summaries from 

each interview set were prepared and provided to the interviewees for review. Not all 

participants responded to the request for review of their interview summary. As a result, the 

information in these interviews was not included in this summary. 

The information provided by the workers and site experts has been invaluable in helping SC&A to 

better understand the Weldon Spring site operations. This report is not a verbatim presentation of 

the material contained in the interview notes, nor is it a statement of SC&A findings or opinions. 

It is a consolidated summary of statements, opinions, observations, and comments that the 

interviewees communicated to SC&A. A few interviewees had extensive knowledge on not only 

Weldon Spring, but Mallinckrodt Chemical Workers. They also actively participated in the MCW 

SEC petition process and had extensive personal knowledge and comments to share related to 

previous reviews and how these reviews impact the Weldon Spring site. The sole intent of this 

summary is to communicate information acquired by SC&A during interviews to the Work Group, 

the Advisory Board, and other interested parties. 

Information provided by the interviewees was based entirely on their personal experience at WS. It 

is recognized that site experts’ and former WS workers’ recollections and statements may need to be 

further substantiated; however, they stand as critical operational feedback and reality reference 

checks. These interview summaries are provided in that context. Key issues raised by site experts 

are similarly reflected in our discussion, either directly or indirectly. Interviews from all workers 

who reviewed and approved their individual interview summaries were consolidated into a single 

summary document. The information was categorized into topical areas related to operations at the 

sites, radiological monitoring, shipping and receiving, environmental monitoring and waste 

management, radiological records, incidents and unusual occurrences, occupational medical, 

technical basis document (TBD)-related comments, and miscellaneous comments. This interview 

summary represents what was communicated to SC&A interviewers by the interviewees. Comments 

or clarifications made by SC&A are provided in brackets. Where conflicting observations and 

statements have been received, both perspectives have been retained in this summary report. 

With the preceding qualifications in mind, this summary has contributed to our understanding of 

issues raised in the site profile. 

OPERATIONS 

The Fruin-Colnon Construction Company of Utah was responsible for building the WS. 

Construction started in 1955, and operations began in 1957. The plant was hopping in 1957, 

1958, and 1959. By 1961, things were a lot quieter, with fewer people out at the plant. Many 

employees from the Destrehan plant were offered work at WS when Destrehan closed. Many 

felt that they had no option but to move or lose their jobs. WS continued operation until 

December 1966, when it shut down. The remediation process began in 1986. 

Mallinckrodt was a producer of chemicals, one of which was diethyl ether. The uranium 

separation process involved diethyl ether, so MCW became involved with the Atomic Energy 

Commission (AEC), because they made ether. 
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The MCW Uranium Division began at Destrehan and continued through WS operations. The 

plant design and practices at WS incorporated many lessons learned from experience at 

Destrehan. At one meeting, NIOSH representatives showed a diagram of the radiation history at 

Destrehan. On a graph, the average radiation level was highest at the beginning; by the time it 

was closed, the radiation level had come down a little bit, but it was still over the danger 

threshold. The WS Plant started at that level and stayed at that level, because all of the safety 

improvements carried over from Destrehan. WS did not use ether in the purification process like 

Destrehan, so WS didn’t have the danger of ether house explosions. At Destrehan, one plant was 

built right next to and/or on top of another plant. At WS, the different plants (e.g., metals plant, 

salt plant, etc.) were at least one or two blocks apart. The exposure levels at WS would be lower 

than those at Destrehan. 

By 1953, the division produced multiple metal products, including “Betatron slices” (see page 

46 of the original Mallinckrodt Exposure matrix)[ORAUT 2005], slabs, billets, ingots made 

from derbies, and dingots (direct ingots) made by an MCW patented process. Because of 

dimensional instability discovered during reactor irradiations at Hanford, MCW had to add 

zirconium, iron, and other elements as an alloyed product. The Department of Energy (DOE) 

Legacy Management outgrowth brochure indicates that the uranium ingots contained small 

amounts of thorium, as well as magnesium, manganese, etc. The dimensions, weight, and exact 

chemical composition of each of these metallic forms needs to be described in detail in order to 

assign a correct radiation dose to those handling the forms with widely varying geometries. 

The material coming into the plant generally originated from Colorado Plateau, although there 

may have been some material from other areas (i.e., Canada, Belgium Congo). The material was 

primarily uranium carbonates (grayish or brownish) that had been filtered out from the ores. 

That came into the Warehouse facility in 55-gallon drums. The drums were not labeled in terms 

of concentration. All they would say is that they came from this facility (i.e., the name of the 

mine). There was some processing at the mine to get rid of the rock, and they ended up with 

70%–80% uranium carbonate. This is what was drummed up and sent to WS. WS’s mission 

was to further concentrate the material. Primarily, the incoming product was ore, but every once 

in a while, they would get drums of some other concoction. WS also received metal cylinders 

from Hanford or some place like that. This material was dissolved and processed like any other 

material. 

The uranium ore and other material were sampled at the sampling plant to test for uranium 

content. Uranium ore concentrates were shipped by train car to WS. The ore was loaded into a 

hopper, sealed, and weighed. There would be up to 3 tons of material in the hopper. The weight 

was recorded on a form, including information about the percentage [of uranium]. 

WS had three separate processes in the production of uranium trioxide; digestion, purification by 

solvent extraction, and denitrification. At the first processing plant, the ore was fed into a 

digester, where it was treated in big vats of nitric acid. The material had to be fed into the 

digester at the correct rate; otherwise it would react with the acid and blow off the top. 

Operators had to monitor how fast material could be fed into the digester; the appropriate rate 

varied with different materials. The resulting aqueous solution was passed through an organic 

solution of diethyl ether; the two liquids were running counter-currently. In that mixing, the 

uranyl nitrate entered the diethyl ether, and the raffinate dropped out. This produced a UNH 
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[uranyl nitrate hexahydrate] aqueous solution. The resulting slurry contained UNH aqueous 

solution, nitric acid, and various impurities. The slurry was mixed with tri-butyl phosphate 

(TBP) in hexane. Raffinate was produced as a byproduct and carried most of the impurities. At 

the end of this process, you end up with yellow salt (i.e., uranium nitrate). The UNH was 

extracted and piped to denitrification pots, where uranium trioxide was made. They cooked the 

uranium slurry in pots over a flame until it was powder. The pots were unloaded with a suction 

system. This would not preclude some of the material becoming caked and individuals having to 

chip it out. This operation generated a lot of dust. 

In the hydrofluorination process, uranium powder [uranium trioxide] was run through screws and 

pipes. The yellow powder was run counter-currently through a bank of screws with anhydrous 

hydrofluoric acid. Screws were used to push the uranium powder through, converting it to 

uranium tetrafluoride [UF4, green salt]. The screws were about 20–25 feet long; they were made 

at WS by curving the metal around and welding it to another piece of metal. A pipe was used to 

move the material from one end to the other. This process was heated and pressurized to keep 

the material moving through the process. The screws were unloaded in dust-protected systems. 

This process posed significant chemical exposure hazards, especially when the tanks were 

unloaded. People wore protective suits for this work. 

In the Metal Plant, UF4 was reduced to uranium metal, and the resulting metal was finished. The 

goal was to get pure metallic uranium. Workers would take the refined green salt (UF4) and mix 

it with elemental magnesium. The mixture was put into a big steel container, about 10 feet in 

circumference at the top, about 4–5 feet in circumference at the bottom, and about 15 feet tall. 

The container was lined with magnesium fluoride and some lime for further insulation. When 

the mixture was heated up to a high enough temperature (~1,300 F) in a furnace, it underwent a 

thermite reaction. The uranium dropped out of its fluoride salt form down to pure metal dingot 

down to the bottom of the container. Remaining slag had to be chipped off the ingot. This work 

was done with a Plexiglas shield. Weldon Spring produced cylinders of highly pure uranium 

metal that were about 17 inches in length by 17–18 inches in diameter. The product weighed 

2,000 to 3,000 lbs. 

The uranium metal was taken to a lathe, where the isotopic impurities would be machined off 

from the very top surface. The surface of the cylinder was clean except for the top layer, where 

it had a pitted appearance that did not look like the rest of the cylinder. They would put it on a 

metal turn table and machine the top down to shiny metal. WS had Bullard Lathes, vertical 

lathes they used to take a 1-inch cut off of the ingot. They would take a deep cut off of it, and 

the chip would just curl off of the ingot. The six-spindle and eight-spindle lathes were enclosed, 

with coolant flowing over the uranium. Even with the coolant, it would turn red. The chip 

would curl off and it was real hot looking. Right out on the end, it would start turning red. 

There was a big well, and the chip would fall down into it and coolant would cover it up and put 

it out. The end result was a very pure ingot, which would be shipped offsite. 

Once the ingot was cleaned up to a certain level, it was put in a salt bath at a certain temperature, 

and it got red hot. They would then go into an extrusion press and were cut to a particular length 

to make rods. In later years, induction furnaces were used in lieu of a salt bath to heat the metal 
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for extrusion. This produced 7-inch diameter rods. This product would head to Hanford, 

Savannah River, or Oak Ridge. 

The end product was sent offsite for quality control analysis. 

All of the pure magnesium used in the metal process was burned up. Magnesium fluoride was a 

byproduct of the magnesium and green salt reaction. It was recovered by putting it through a 

sieve to remove the metal elements or other elements, so the magnesium could be captured for 

reuse. It was put into a grinder to break it up into a powder; then it was put into the shells and 

packed with mandrels. 

The Bullard Lathes required periodic repair of the pumps and adjustments by the operators. The 

guys that ran the Bullard Lathes wore rubber gloves. All of the coolant was contaminated. 

There would be shaving particles in the air. The layer with impurities that was cut from the ingot 

would be turned into black oxide inside the rotary kiln. 

There were ongoing experiments and testing done by manufacturing at the Pilot Plant. These 

were done on a small scale. For example, they were trying to grow seeds. General Electric 

would take this material, drop it down into a hopper and vibrate it down, and it would come into 

an electric welder and tried to make seed. There were a lot of test projects going on that only the 

people working on them knew about. These projects had special handling and were sent out for 

evaluation. Some samples were sent down to the storeroom, put into a pickup, and taken to be xrayed somewhere. The storekeepers were in charge of this. 

The raffinate generated by WS was kept onsite. Initially (i.e., ~1957–1958), the raffinate was 

pumped into drums. There were several quarries out by the WS. For a few years, those drums 

were dumped in quarries. Later, they started to collect raffinate in a stainless steel tank, adding 

lime and pumping it out into a pit for evaporation. The operators were responsible for sampling 

the raffinate and neutralizing it before pumping it out to the tank holding area for disposal. 

When a raffinate tank was full, operators would take a sample with a stainless steel cup on a 

chain. They dropped it down into the tank, collected a sample, pulled it back up, and put it into a 

sample container. The sample was taken to the laboratory and checked for pH. The lab would 

tell the operators how to neutralize it. A neutralizer was added, the material was agitated for 

maybe 20 minutes, and another sample was taken to the lab. When the laboratory determined the 

acid was neutralized, the raffinate was pumped out to a pit, and the sun was supposed to dry it 

out. At one point, they talked about recovering minerals from the dried material, but it never did 

materialize, because the raffinate didn’t dry out enough. The rain water kept it from drying out. 

Later on, they put cast iron pipes in the system. If the raffinate wasn’t neutralized enough, it 

would eat the pipes. 

Enriched uranium [~3%, according to H&S site experts] came in as a hexafluoride gas in about 

early 1958. This was a small run campaign that didn’t go on very long. When WS received 

enriched uranium, staff was required to go down to Oak Ridge for 4 months and work with a 

criticality expert. The appropriate process for handling this material at WS was determined in 

order to prevent any potential criticality problems. The only change in the Radiation Protection 

program during handling of enriched uranium was to make sure that the volumes and masses 
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were kept in check to prevent a criticality. Other than that, it was treated like normal uranium. 

Individuals were not monitored any differently. 

Recycled Uranium (RU) 

Interviewees observed that, officially, the remediation crews deny that they received recycled 

uranium (RU, material that was previously irradiated in a reactor) at WS. Interviewees 

expressed concern that the source term characterization is incomplete in this regard. They think 

MCW and WS, and even upper levels at DOE, are incorrectly denying or underestimating the 

presence of RU on site. 

DOE tracked fissionable materials, including RU, around the complex. There are several tables 

tracking the shipment of material. Documents retrieved from Oak Ridge (Recycled Uranium 

Mass Transfer Ohio field report mentioned in the site profile) and a handwritten memo from an 

unidentified participant at a symposium indicated that 74,800 metric tons of uranium containing 

small amounts of plutonium, neptunium, and americium were shipped to and from 

“Mallinckrodt” and/or “Weldon Spring” from 1962–1967. In addition, MCW records alluding to 

urine sampling for plutonium were retrieved from the Oak Ridge Associated Universities Center 

for Epidemiologic Research vaults. 

Interviewees further noted that documents from lower levels are in conflict with the higher-up 

DOE reports. Officials of the DOE Weldon Spring Site Remedial Action Project team denied 

that the site ever received RU shipments, although DOE field office reports indicate that it did. 

A statement in the WS site profile (“most of the uranium was natural”) seems to deny that RU 

was present, but the interviewees claim that 70,000–74,000 metric tons of RU can’t be so lightly 

dismissed in the site profile, like it didn’t happen. 

The interviewees made a number of points (as follows): The instruction provided in the site 

profile was based on an inaccurate definition of the amount (mass) of RU-transuranic source 

terms. There is a disconnect between saying RU is not there and coming up with assumptions 

for dose reconstruction on RU. The dose reconstruction is supposed to be claimant favorable and 

also plausible. Plausibility is required to prevent assumptions that were made, where the 

amounts of RU-transuranics were wildly under-reported (based on the RU mass transfer field 

report cited in the WS site profile). Making things up out of thin air violates the intention of the 

SEC law. 

The interviewees who raised this concern believe that every effort should be made to discover 

the relevant records at DOE. It is difficult to track exactly what went to MCW. As a practical 

matter for dose reconstruction, interviewees stated that the amount of RU source material is not 

known. Without this knowledge, the interviewees believe that they can’t apportion the dose 

reconstruction to RU. 

Maintenance 

There was a Maintenance Foreman assigned to each building, who was responsible for keeping 

that plant up and running. A small crew, perhaps a couple of mechanics, an electrician, and/or a 

pipefitter, would be assigned to a building. The assigned crew took care of routine maintenance 
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and emergencies. If a big job came up, they called the central maintenance pool for support. 

Workers from the central pool were assigned out to different buildings, making it possible for 

such individuals to work anywhere on site. There were no restrictions on where individuals 

could go at the plant. Electricians were responsible for conducting inspections of lines, 

insulators, and breakers when the plant was taken down (i.e., during the holidays). Access was 

controlled by a single guard station at the gate. 

The plant furnished general maintenance tools, which were carried around to the plant areas. 

Special tools required for the job were available at the job location. 

WS had one large maintenance building that contained a machine shop, weld shop, an electric 

shop, and an instrument machine shop. The building had a big aisle down the front end of it 

from one end to the other. On one side of the aisle was a storage area. The machining area had 

lathes and a big radial drill press; machinists could do everything on that drill press. It was 

separated from the other areas by chicken wire. 

Transportation 

Couriers intermittently went to all the buildings where people worked, delivering the mail to the 

plant population. Couriers were also responsible for transporting Oak Ridge visitors to the plant. 

There were three mail runs through the plant each day (morning, afternoon, and evening). 

Couriers also picked stuff up at the shipping dock and transported it downtown twice a day. 

Couriers also carried a lot of product out of WS, including samples or cores. The material was 

transported in a wooden crate that was marked with a yellow crayon. The crates were 

transported one at a time in an AEC pickup truck to the Destrehan. Couriers would go to the 

receiving dock, take the crate off the dock, put it in the vehicle, take it down to Destrehan, and 

unload the vehicle at the Shipping and Receiving building. The contents of the crates appeared 

to be three or four pieces of metal with hack marks on them. A couple of times, cores were 

transported for analysis. 

Offsite Contract Work 

MCW at Destrehan and WS had some offsite contract work. Two sites they contracted with 

were General Steel Industries (GSI) in Granite City, Illinois, and Dow Chemical in Madison, 

Illinois. 

GSI had two particle accelerators (Allis-Chalmers 24–25 MeV Betatrons serviced by Picker 

X-ray) to inspect large scale items. WS wanted to identify cracks in the uranium dingots. 

Subsequent research has shown that another key purpose of GSI Betatron Non-Destructive 

Testing (NDT) x-ray work was to define the thickness of the outer non-uranium crust on the top, 

bottom, and sides of the MCW direct ingots (dingots). This was part of the quality assurance of 

the production runs at WS. 

MCW–Destrehan made “Betatron slices” of uranium [ORAUT 2005, pg. 45]. They would stack 

these up and send them over to GSI. Weldon Spring also held a contract with GSI from 1953–

1966 for evaluation of uranium. Slices were shipped to GSI after 1953. The materials were sent 
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by truck or rail. When they were sent by truck, MCW drivers were to accompany the slices. 

GSI would take an x-ray film and check to see if the product was of adequate quality. This 

information was sent back to WS. 

In the case of Dow Madison, WS-MCW Uranium Division/AEC had a contract from 1957 to 

1960 to perform experimental research and development on uranium “R&D gamma extrusions” 

and rod straightening. Some of the work done at Dow Madison in Illinois is not mentioned at all 

in the site profile, and it should be. Any AEC technical reports on the results of the experimental 

gamma phase extrusion on uranium at Dow Madison should also be referenced in the WS site 

profile; they are not currently cited. It is unbelievable that only a few work orders and no 

technical reports survived. They were doing experimental extrusion work with uranium to 

obtain more details on the techniques. At that time, they didn’t know how to work very well 

with thorium. 

RADIOLOGICAL CONTROL 

The H&S department at WS initially encompassed all aspects of H&S, including Medical, the 

analytical laboratory, field monitoring, personnel monitoring, environmental sampling, and 

industrial hygiene. There was no other department or unit in this area. In the Weldon Spring 

Plant H&S group there was a manager, three individuals in analytical support (i.e., bioassay, film 

badge processing, sample analysis, instrumentation), and about four men in the field group 

responsible for sampling. Most of the staff remained consistent throughout operation, but a few 

were replaced. The H&S department worked closely with plant management and the AEC. 

They were in contact with the New York Operations Office H&S laboratory, Rochester 

University, and Oak Ridge. Their dealings with New York had to do with bioassay sampling 

rather than processes. At WS, H&S had enough time to start things up, get the lab going, find all 

of the procedures they were going to use, and staff the department. 

There were procedures and requirements for some of the operations. There was a safety 

procedure and notification system for the arrival of anhydrous HF [hydrofluoric acid] tankers; 

this procedure included routine checks to verify that the workers wore their rubber suits and air 

masks. There was probably a procedure for unloading the ore concentrate. 

MCW seemed to be more open about the operations at WS and there was a lot more emphasis on 

safety, compared to the downtown Destrehan Plant. The unions held meetings in the shop. In 

the plant, every month they would go from one facility to another to learn about what was going 

on. However, workers noted that they did not receive training on how to work with uranium. 

Workers generally lacked understanding of the radiological hazards associated with uranium; 

they did not know there was a reason to be concerned. Only personnel who had transferred 

from the St. Louis Plant had acquired some low-level experience working in uranium processing; 

the new hires at WS depended on information obtained through safety meetings covering both 

industrial (i.e., electrical) safety and chemical operations within the plant. 

Even though new processes implemented at WS showed improvement, many later created new 

problems. Then too, production output at WS far exceeded that which was produced at the St. 

Louis Plant. The workers had little knowledge that the additional output exposed them to a 
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much higher radiation dosage; some interviewees concluded that most job assignments were at 

risk due to a lack of knowledge and training. 

Plant Conditions & Contamination Control

From the start, WS primarily dealt with natural uranium. At one point in time, slightly enriched 

uranium (~3%) was handled on site. Uranium is basically an alpha emitter; there was very little 

gamma and very little beta. Without any significant gamma, uranium didn’t pose an external 

radiation hazard; the skin would stop alpha and beta from getting through. There was some 

external dose from the raffinate, which would carry other radioactive impurities from the 

incoming ore concentrates, but the primary concern for H&S was to control exposure to 

breathable particulates. This rationale was supported by the AEC National Health and Safety 

Offices. 

They were also saying at the time that in terms of radiation, there was a certain level of radiation 

the human body could tolerate. For example, the natural radiation exposure in the St. Louis area 

is different from the exposure received by people living in Denver. That difference in radiation 

has been with us throughout time. In those days, there was not a significant worry about the 

accumulation of radiation over a person’s lifetime. 

Depending on what plant a worker was in, they may be exposed to uranyl nitrate (UNO3), ore 

concentrates, uranium tetrafluoride, or uranium metal. There was potential contact with green 

salt (UF4) in the metal reduction process. In the machining process, there was some potential for 

exposure to uranium metal and oxide. In addition, exposure to oxides was possible from the 

clean-out of the magnesium fluoride to make new refracting material. Minute particles would 

come, some of which contained the radioactive contaminants they were trying to remove. 

Workers were also exposed to the byproducts of the uranium processing. 

There was mention of thorium being handled at WS. There could have been some decay 

products in the material machined from the uranium metal, and thorium was found in the 

raffinate. 

There were three major health hazards that H&S really looked for in the yellow cake operation: 

how to handle the sludge and raffinate; how to control the potential fire hazard; and how to 

control the powdery uranium nitrate salt during evaporation and drying. Significant dust control 

and protection was needed. 

In comparison to Destrehan, WS was a fairly clean plant. The amount of dust encountered in the 

work area depended on the area in which you worked. In the processes, everything in the green 

salt and yellow salt plants was closed, except for the cooking pots in the yellow salt plants. They 

had dust collection around them. There was very little chance to get escapes other than some 

kind of failure (hood system, filters, etc.). Some interviewees mentioned issues with heavy dust 

in the pot room. Workers noticed dust visible in the air in the refinery. In the refinery, dust 

would build up on the high voltage transmission lines to a point where the cross arm would get 

burned. Electricians had to clean insulators at least once per year. While weighing hoppers, 

some dust and spillage from the hoppers would fall on the scale floor. In the extrusion area, hot 
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gases came off the uranium into the air; they are visible in pictures. When they machined the 

uranium, there were shaving particles shooting through the air. 

[The green salt plant contained] three banks of furnaces. There was leakage around the drive end 

of screws (i.e., agars) used to turn the uranium to green salt. Green salt is a bluish-green color, 

and it was heavy like the regular uranium metal. Some packing leaked around the fluid bed. 

Workers would take orange oxide, run it down to the fluid bed, and convert it to brown oxide. It 

went to the other end of the screw. The hydrofluoric acid would start to turn it into green salt. A 

lot of times, when the hydraulic pressure in one screw would get too great, the screw would lock 

up. They would notice this at the panel board. If they sped it up too much with the hydraulic 

pressure to turn that screw, a lot of times it would break. If the screw broke, they would have to 

shut that bank of furnaces down. They would have to call the maintenance crew over, pull the 

screw out, bring it out over the whole plant area with a hoist, drop it onto the floor, and crack the 

wet green salt off of the screw. They salvaged what they could of the green salt. They broke it 

up and got rid of the scrap material; at one time, they dumped the contaminated scrap in the 

quarry. 

Acid fumes were a major problem in the refinery; they painted all of the metal girders with acidresistant paint. There was no buildup of material in the breaker boxes, because they were 

explosion-proof and solidly sealed, so that no spark could set off an explosion, but acid residue 

was visible when the breakers were opened. 

There were chemical vapors (i.e., hydrofluoric acid fumes) coming out of the fluorination 

process all the time. The fumes could be overwhelming. Maintenance workers had to go over 

there and take up on the packing. To pack them right, the worker cut the packing at an angle. 

They would put one opening where it would wrap around, and push that in with a flange. 

Additional packing would be on the other side on the bottom. Usually, it took about five or six 

packing strips. If they were not cut just right, the gases would come back through them. As it 

was packed, the packing would wear out on the inside. Workers would have to add packing to 

take up that space where the gases were leaking through. Once the gases got in there and start 

eating through too much, they start grinding away on the journal of the screw. As the metal of 

the screw became corroded and worn down, more leakage would occur. The leaks would get so 

bad that the maintenance man would have to go out and fix it if he could. A mask was required, 

but it didn’t seem to stop anything; sometimes the mask wouldn’t operate properly. The 

maintenance worker would take a deep breath, go in and take up on that screw as much as 

possible, and go back out again for air. 

There was a lot of residue around the process area. Up on the top floor, workers used to hoist up 

20,000 lbs of orange oxide. They had a well area that went clear to the top of the building. The 

trucks would bring the big containers in, and the plant worker would let the hook down, hook up 

the tank, and bring it up by hoist. Then they would bring it up to the different banks of furnaces. 

The orange oxide from the tank funneled down and dropped into a screw and went down to the 

fluid bed. When they opened the valve where that orange oxide came through, a lot of dust 

would be piled up from the vibration. That stuff would leak out and run out on the area where 

they set the tank. Orange oxide was all over the place. Workers used vacuums to try to keep the 

area clean. 
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There were big jolters that used to take the shells and bounce them down to pack the liner down. 

It had four bolts with 2 to 3 inch hexagon nuts that would hold them down. The studs would 

come up out of there. This thing would work itself loose. A worker would have to go down and 

tighten up on the screws to keep it from shaking. Sometimes, an attempt to tighten the bolt 

caused it to break off; the constant jolting just deteriorates the metal. 

Some jobs caused more radiation exposure than other jobs. One example was picking up a die 

out of the extrusion area. There was a large bank of hydraulic engines that pushed the uranium 

through a die. It would extrude a 2-inch rod, squeezing it out like toothpaste. The rods were 

about 15–20 feet long. As the stuff would go through the die, it would tear and scrape and form 

black oxide. The black oxide would form around the dies and stay there. 

There is some disagreement among workers regarding the extent of contamination spread and the 

potential for incidental exposure. For example, interviewees from H&S did not recall any visible 

contamination on cars in the parking lot, but some other workers reported this type of 

contamination. Some workers reported that contamination was sometimes tracked in to the 

administrative office areas, other non-radiological areas, or outside, but others disagreed. 

Some workers expressed concern that cars parked in the plant area were becoming contaminated, 

and non-production workers were exposed when they rode in these cars. Cars were parked 

between the Administrative Building and the Foundry. The whole area was dusty and gritty. 

The dust and grit came from the stacks and would settle on the cars. It was like gray sand. Some 

guys had to have their cars repainted. One individual who parked his car in the parking lot got 

into an automobile accident; when the body shop pulled the panel off his car to fix it, it was 

loaded with yellow material. The plant sometimes sold its transport cars or traded them in; some 

cars had to be buried, because they were radioactive. 

Depending on the wind, the office people at times would get a good blast of that dust and dirt. 

The ventilation system in the Administrative building brought contaminants into the building. 

Some workers noticed when they went to the cafeteria that there was yellow dust from the plant 

on some tables that were not regularly used. In addition, the plant workers were supposed to 

take a shower before they left work, but not all of them did. Any contamination on these 

workers potentially exposed other workers. 

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 off. They were not required to call a radiation monitor to take measurements. If they 

did, they would never get any production done. 

WS had a decontamination crew. A bunch of guys would run around all day long with rags, 

buckets, and sponges, decontaminating. 
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Monitoring/Surveys 

Part of “monitoring” would involve looking at each step and evaluating the needs and actual 

performance of safety systems. When the plant was starting up, H&S analyzed each phase of 

operation. They looked at chemical exposures, where the dust could come out, how to contain 

the hazards, etc. During an evaluation, H&S tried to answer the following questions: What were 

the incoming materials? What were the outgoing materials? What kinds of hazards were 

present? These analyses were documented in reports, with the department listed as the author. 

H&S also conducted analyses when there was any kind of process change (i.e., new chemical, 

new station, new piece of equipment, etc.). The analysis included air sampling and survey 

measurements, as well as evaluating engineering controls. For instance, is the dust collection 

adequate where the cook vats of uranium nitrate are dumped? Is it containing everything or not? 

The hazards identified through this process, both chemical and radiological, were monitored on a 

regular basis. H&S would monitor all phases of the plant regularly (a minimum of annually, but 

probably more like every other month). Every piece of H&S hardware associated with the 

operation would be monitored on a regular basis. 

Geiger Counters were used to take readings in the plants. Staff would go out to the metal plant 

and check the readings over there. They might check the radiation level on the drums coming in 

with the ore, or the sludge. 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. 

Air Sampling 

When H&S monitored a unit, they would use air pumps strategically located around the facility. 

During hazard evaluation studies, air samplers with filters were taken to the plants and run for a 

certain amount of time. There was no routine monitoring station in the plant that ran 24/7. 

Occasionally, H&S would monitor an operator with a breathing zone air sampler. This was not 

done very often, only in response to a concern. For example, if puffs of dust were observed at a 

particular unit, or if the air flow over the dust collector bags was too low, they would put a filter 

collection device around the operator’s neck. A pump was used to keep the air moving, so that 

any dust coming out during the monitoring time would be captured by the Millipore filter. The 

Tygon tube hung over the shoulder of the monitored person. 

There were no formal particle size studies; however, WS did studies with Millipore filters and 

other filters with different size holes. Filters were analyzed for uranium concentration. 
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Personnel Protective Equipment and Work Practice Controls 

Everybody entered the plant through the Administrative building. Many workers changed from 

their street clothes to coveralls when they came into the plant. The workers followed procedures 

for dressing out. They were constantly cautioned about not taking any of their work clothes 

home. Upon entering the plant, workers took off their street clothes and put them in their 

lockers. They went through the change room and got a whole new issue of clothes (i.e., socks, 

shoes, underwear, coveralls, hat, gloves (if needed), etc.). 

Protective clothing requirements varied, and not all workers were required to wear coveralls. 

Those that worked in the area may have coveralls, but those who went in and out of the areas did 

not. In the Refinery, they all wore supplied clothing (i.e., underwear, socks, coveralls, and 

masks). By the end of the day, coveralls were dirty. Workers didn’t always use common sense. 

For example, some workers would go to the shop with green salt on their clothes. 

The radiological clothing was laundered onsite. The laundry wasn’t located in any of the three 

operating units. The interviewees did not recall routine monitoring of the laundry, but believe 

that the waste water was probably collected. It probably went to the same place as the sludge. 

The general policy at WS was that employees were not supposed to eat or drink in the process 

areas. Workers were supposed to leave their lunch bucket in the Administrative building. The 

facility had a cafeteria where individuals ate lunch or dinner. There were also break rooms 

available where the workers would eat, drink, and/or smoke. To get to the break rooms, they 

would exit the production area. Workers were supposed to wash their hands when they went into 

a break room, but many workers did not do this. Some individuals drank coffee in their work 

area; there was no concern at the time that it might be contaminated. At the Weldon Spring 

Interpretive Center, there is a picture of individuals cutting a birthday cake on top of an ingot, 

indicating that some eating was taking place around radioactive material. There were drinking 

fountains in the break rooms and other areas of the process plants. There was a potential for 

radioactive material to be tracked into the break rooms by workers. 

Some interviewees reported showering and changing into street clothes prior to going to lunch or 

leaving for home, while others said they did not. If they were working in a dirty area and had 

contaminants on them, they would shower. When they went back to work after lunch, they 

would get a whole new set of clothes. The shower was a poor design, and if a guy didn’t want to 

shower, he could walk through the middle and not get a drop of water on him. Workers from a 

“regular job” would just put on their own clothes and boots and go to the cafeteria. Some 

workers entering and passing through areas were not required to shower when they left for the 

day or went to lunch. There were times when some workers wore their shoe covers and coveralls 

to the cafeteria. 

Gloves were used to protect the hands from chemicals and physical conditions (e.g., heat and 

cold), but they were not routinely used for radiological protection. The electricians were 

supposed to wear gloves, but some couldn’t work with gloves on. 

Depending on the atmosphere in an area, workers usually had to wear a dust mask to enter. 

There were a few different types of masks used for respiratory protection at WS. One type of 
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mask would come down over the worker’s nose, even with the chin. The actual filter fit up 

inside of this thing. It was aluminum and plastic. The plastic held these dust filters inside of 

there. A rubber fitting around the aluminum was used to push the aluminum in tight around the 

face. These masks did not seal well; no matter how hard a worker tried, they leaked. Later on, 

WS had half-face respirators with two chemical filters, similar to an Army mask. The cartridges 

were selected based on the hazard anticipated for the particular operation. These were much 

better, but some leakage still occurred. A lot of times, if they were really concerned, they used a 

full airline mask with air hooked up. These were often used for dealing with leaks in the green 

salt area because of the hydrofluoric acid; workers also wore rubber suits and cover boots in this 

environment. When they used air-line respirators, another operator or technician had to stand by 

to make sure that the air was regulated for the duration. This was especially true if the worker 

was going inside a closed area with an air-line mask. 

Respiratory protection was worn by some workers, but not all. Individuals who walked through 

production areas to get to offices observed that some workers had respirators on while others did 

not. When masks or respirators were used, they were worn more than once; workers just 

changed the filter out. They were not sent to the laundry between uses; workers simply took a 

rag and wiped them out. Those workers with respirators stored them in their lockers between 

uses. Some of the filters were like a paper filter. The workers would just throw the paper filters 

away when they were too dirty. There were never any problems getting a new filter. They 

would just throw these away. Workers kept their masks hanging around their necks as they 

worked, in case they needed it. Masks were primarily used to protect against breathing in the 

uranium dust. 

When the vacuum system went down, workers would have to get in there and scoop the uranium 

out; otherwise it would burn up in the pots. Dust would get on the outside and inside of the 

mask. When a worker got finished and pulled off the mask, he would have orange all around his 

mouth. 

Time limits may have been used to limit the time the individuals sat at the lathes, but not in the 

yellow or green salt plants. 

There were situations where employees would sit on the uranium metal. There wasn’t a place to 

sit in the plant, so the uranium offered a place to sit down for a minute or two. 

The mail was brought up to the messengers’ work area and sorted by the mail clerks. At times, 

foam containers with radioactive labels were sitting there; these usually held material from WS 

that had to be taken to the downtown site. These containers would sometimes sit on or by a desk 

where someone was working. Some of the workers looking back on this situation now think that 

MCW wasn’t taking care of them. 

Engineering Controls 

The material potentially released to the environment depended on the building. Each building 

had major dust collectors. These dust collectors were like big huge bags, and a big motor would 

suck the air through the bags. There was big vacuum system with two big metal rings and large 

bags in them. Workers would have to connect them at the top and the bottom. The exhaust 
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system on that would cause the vacuum to pick up the stuff in the plant (e.g., spilled green salt, 

black oxide, etc.) It would go up into the bags, and the rings would move up and down. This 

would shake the stuff off at the bottom. There was a hopper underneath; as the dust collected on 

the sides, it became heavy and dropped into the hopper. A building might have a couple of main 

vacuum systems. There were several bags in each system; they were several feet long and about 

18 inches in diameter. They were big enough to fit in a 55-gallon drum. They would recover the 

dust and send it back to the refinery. When the bags got clogged and the pressure would get 

high, a ring collector would start up, with air blowing from the outside of the bag to the inside, to 

knock the material down. Sometimes a bag split, and dust got all over the place; the operators, 

millwrights, and electricians would have to go clean up the mess. Major breakdowns may have 

caused releases to the environment. 

WS used hoods during sampling of drums (material coming in). There was also a hood where 

they took samples from the process system. Any place where there was a potential for contact 

would have a dust collection system. H&S was responsible for checking out the ventilation 

systems. 

Local 1 International Brotherhood of Electrical Workers quorum has attended many meetings 

regarding the safety requirements issue at Weldon Springs. They maintain that flaws in the 

equipment and full production process contributed to more radiation dosage and resulting health 

problems among the union’s workers. Design Engineering could have done a much better job, 

since MCW had previously processed uranium in the very early 1940s. 

Many of the operations at WS were hands-on versus remote operations. The guys would have 

their hands all over the 500 pounders. They were chipping it off after it came out, and they 

would take them and machine them. 

Receiving the ore concentrates and the boiling down of the uranyl nitrate were probably the most 

hazardous processes from a uranium standpoint. Unloading of the anhydrous HF tanks also 

produced very challenging field conditions. 

WS was under the jurisdiction of the Oak Ridge Operations Office. The AEC came down to do 

regular audits on some time basis. H&S staff members were not aware of any state inspectors 

reviewing the facility during operation. The state deferred this responsibility to the AEC. 

PERSONNEL MONITORING 

When Weldon Spring opened up, they needed to have a laboratory established in the H&S 

department to perform bioassays, air sample analysis, and all analyses associated with H&S. 

Film badges were processed and calibrated at this laboratory facility. The only dosimeters 

employees worked with were film badges. 

External 

The general rule for external monitoring of individuals at WS was that individuals working in the 

plant were assigned a film badge. No one was supposed to go in the plant without a film badge. 

For example, if an individual routinely went out to the plant area, even though they were 
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assigned to the Administrative area, they were supposed to wear a radiation badge. 

Management, security, and warehouse support personnel would have been assigned a radiation 

badge if they were out in the plant area. At least some supervisors/foremen told their employees 

to wear their film badge when they were out in the plant area. Some individuals reported that 

they did not wear their film badge consistently when they were out in the plant area. Some 

Administrative personnel at WS indicated that they did not wear a film badge. There are reports 

that individuals placed their badges on or in uranium to see if they would receive an elevated 

dose result. 

The frequency of routine badge exchange was monthly or quarterly. The badge was worn over 

the pocket area on the chest. Some individuals indicated that they wore the badge inside the 

pocket, while others wore it on the outside. Individuals were not allowed to take their radiation 

badges home, but were told to store then in a rack by the guard shack. Workers wearing film

badges picked up their badge when they came to work and returned it at the end of the work day. 

Personnel involved in transportation of material offsite indicated they left their badge at the 

guard shack (where they were stored) when leaving the facility with material. 

Initially, some pencil dosimeters may have been assigned, but a decision was made, with AEC 

concurrence, that these were not needed. There was no neutron monitoring at WS, even during 

the work with enriched uranium. Extremity dosimetry was not used at WS. There was not a 

routine area dosimetry program, but dosimeters were put in the area during special plant 

evaluations. 

There were times when film badges were lost, damaged, or contaminated. If the film was 

damaged or black, an investigation was done to find out what happened to the film. (For 

example: Did the worker leave it on top of a metal cylinder? Did the worker have it on during 

an x-ray?) 

WS maintained manual calibration curves for the film badges. Radium needles from the 

National Bureau of Standards were used to calibrate the film badges. The radium needles were 

kept in lead shields. The film was exposed for a specific amount of time to a known amount of 

radiation, and this information was used to calibrate the densitometer. All film badges were 

read, unless they were lost or misplaced. The film was read for gamma (rad) and beta (rep) dose. 

Beta wasn’t as much of a concern, since it can’t get through the epidermal layers of the skin. 

There was no background subtraction from film badges. 

Internal Monitoring 

The personnel in the analytical laboratory determined bioassay requirements. They primarily 

analyzed for uranium in urine, but fecal sampling may have been done on occasion under 

unusual circumstances. 

Routine bioassay sampling intervals ranged from weekly to annually. The nitrate plant, green 

salt plant, and metal plant had a regular weekly collection schedule. These were typically 

collected as spot samples. Each plant had a separate collection day; it was divided up, so the 

laboratory workload would be even. If a filter bag broke and a guy got covered with dust, they 

might run a 24-hour sample on that person after he was decontaminated. Occasionally, a worker 
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on a special job might have to submit additional samples. Even workers who had transferred 

from radiological to non-radiological areas indicated that bioassay sampling was continued for 

the duration of their employment. 

Urine samples were generally collected at work; however, there were special occasions when 

urine was collected over a weekend. Workers were provided with urine sample containers in the 

locker rooms, where the collection was done. The lab would collect the samples from there. A 

sign was posted at the container station with the bioassay collection instructions, including the 

instruction to wash hands before providing a sample. This instruction apparently was not 

consistently followed; several workers indicated that they did not recall having to shower or 

wash their hands prior to collection. 

Workers who had an incident were sent to the dispensary. For example, if a worker opened the 

dust bags and they were split, they would get material on them. If this happened, the worker 

would shower off at the plant and go to the dispensary to leave a urine sample. At the 

dispensary, the worker was checked over to see if anything had gotten into the mouth, eyes, etc. 

This would be something similar to a medical exam. These kinds of things happened 

occasionally. When there was a high reading on the radiation badge, workers recall being sent to 

the dispensary to collect urine bioassay. The only thing WS did for exposure was to take a urine 

sample. In some cases, workers were allowed to “cool off” for a period of time. For any 24-

hour samples, H&S arranged to have it taken at the dispensary. 

There were formal procedures for bioassay analysis. When samples (air filters, urine, etc.) were 

analyzed, WS used a fluorometer to determine the micrograms per volume in the sample. WS 

used some of the equipment designs from the University of Rochester laboratory. One of the 

things they designed was a multi-arm spoke wheel with platinum arms that had a little loop at the 

end. Uranium fluoresces if it gets into the right type of crystal (such as a glass substance). This 

substance would be set in the loop, it would rotate through the fluorometer, and a fluorescence 

measurement would be taken from the sample. The fluorescence unit was calibrated using 

standards; the uranium flouorescence of the sample was compared back to that of the calibration 

standard to determine the amount of uranium present. With the fluorometer, the laboratory was 

able to determine very low concentrations of uranium in urine. The method was also capable of 

determining very high concentrations in terms of personal dust samples collected from the nitrate 

cooking pot area. Natural uranium concentrations in urine were not subtracted from bioassay 

results. 

Results from bioassays were recorded in laboratory logbooks. These should be used as the 

source of bioassay results. The internal dose or permissible body burden was not routinely 

calculated. 

The analytical lab did not receive blind bioassay samples from the AEC, although the AEC may 

have come in to observe and evaluate the bioassay program. Positive bioassay results did occur 

among workers at WS. One worker indicated that even after transferring to an office job, the 

worker’s urine samples still remained positive. The AEC waited to hear from WS to report any 

problems. For example, at one time, a particular department was getting higher concentrations 

of uranium in urine than normal. A report was sent to top management stating that the 
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department was having a problem, since many of the operators were showing up with higher 

uranium in the urinalyses. In cases like this, the AEC might come down and help H&S try to fix 

the problem. 

There was a situation where a staff member disagreed with the concentration levels derived for 

safety by the AEC for uranium. An experiment was conducted where a teaspoon of uranium was 

mixed up and ingested. Follow-up evaluation of the individual’s urine was conducted over the 

next 24 hours. 

Interviewees do not recall receiving whole-body or lung counts on the portable Y-12 counter. 

Interviewees also did not recall doing Radon Breath Analysis. There were no identified 

problems with radon. 

ENVIRONMENTAL MONITORING/REMEDIATION 

There was contamination outside the immediate process facilities. H&S did monitoring of the 

environment (creeks, wells around the quarries, etc.) during operation. WS measured external 

dose in the environment with Geiger counters. For example, if H&S walked down to the creek 

and saw yellow stuff in the creek bed, they would take measurements. Uranium carbonate is 

yellow, and it had the greatest potential for release. Interviewees did not recall any significant 

spills of uranyl nitrate or green salt offsite. Environmental samples were collected and analyzed 

for uranium. 

Some monitoring of environmental air emissions was done, but they did not have any built-in air 

sampling equipment that operated regularly. 

There were occasional releases of hydrogen fluoride that would turn the trees brown. Neighbors 

would have complained about the odor and fumes from the plant offsite. When it was foggy, the 

stuff would hang into the air. 

There was a big vacuum system on the green salt plant where the off gases would come out the 

roof and exhaust. Some major breakdowns of dust collectors may have released puffs to the 

environment. There were occasional releases of nitric oxide gases. There was at least one 

occasion in which HF got loose. There was a situation at WS where the plant started losing 

water from a tank inside the area and it leaked out into the lakes in the area. 

An individual was responsible for going out in a boat on the pond and collecting samples. Some

unusual animals were collected from the ponds out in the plant. For example, some frogs with 

three eyes and too many legs were collected. 

There was an approximately 150-foot tower at WS. They recovered all the nitric acid from 

different operations and pulled it into a nitric acid recovery system. They had water going down 

on to this to control the pH. If the operator wasn’t paying attention, the acid would get much 

stronger, because there wasn’t enough water. Sometimes the tower would look like red fire was 

coming out. Sometimes a trail of damage was visible as a path across the trees. 
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The residues from the main plant (Destrehan) were dumped at Weldon Spring, resulting in 

potential exposure to K-65 material, residues of barium, aluminum, calcium, magnesium, cobalt, 

copper, beryllium, iron, manganese, arsenic, asbestos, cadmium, chromium, nickel, antimony, 

zinc, selenium, ionium, uranium oxide, and uranium dioxide. 

The quarries were down the road from the plant. Sampling was performed at the quarries, 

including checking the wells and collecting air samples. AEC at some time probably came down 

to audit WS and indicated a need for improvement. Sludge samples were probably collected and 

analyzed, but the location of these records is unknown. A good part of the solid radioactive 

waste also went into the raffinate pits. 

The interviewees did not know exactly where the drinking water supply for the plant came from. 

There were wells at the site; there was also a water plant down the road about 1.5 miles. There 

were folks that worked for MCW down at the water plant. 

The Weldon Spring Quarry site is close to and within direct sight of the St. Charles drinking 

water “well field” source. Concerns were raised by the public over contaminated drinking water 

around the site. Of particular interest was a study done by the Missouri Department of Health on 

an infant death cluster identified in the area of Weldon Spring. The investigation included 

surveillance-based cluster analysis and a case-control study for offsite personnel. 

OCCUPATIONAL MEDICAL 

The Medical Facility was located in the Administrative Building. Workers received medical 

exams either annually or every 6 months; these included a physical exam, urinalysis, and other 

medical tests. They were very thorough. Interviewees reported receiving chest x-rays as 

frequently as annually. Physicians from Barnes Hospital came to the plant once a week to 

conduct these physicals. 

INCIDENTS AND UNUSUAL OCCURRENCES 

Incidents and accidents, such as a bag failure, would be documented by the department in which 

the failure occurred. Incident reports were not generated specifically by H&S. This information 

may have been discussed in monthly or weekly reports. Historical incidents that have been 

reported publicly by former workers have varied in significance from minimal to severe. 

From the H&S perspective, staff primarily wanted to know bioassay results—how much uranium 

was in the body? H&S reported occurrences and trends to the plant management and to AEC 

when a particular group had more uranium over time than other groups. The action levels (in 

mg/liter) and guidelines were based on whatever was published by the AEC, and were not 

specific to WS. 

The big bomb ovens (electric ovens) in the Metals Plant at WS were of the same construction as 

at Destrehan. From time to time, a blowout would occur during the thermite reaction in the big 

shells. A blowout occurred when something went wrong with the shell or liner (the liner wasn’t 

thick enough, the liner had a flaw in it, or there was a misfiring of the elements). The metal, 

rather than settling at the bottom of the shell, would burn through the liner and the metal 
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container, spewing everything into the furnace. Some spilled outside the furnace, too. A 

blowout in the furnace would destroy the furnace elements, the liner, and everything else. 

Blowouts occurred often enough that they had procedures in place to prevent physical injuries 

when they did occur. At one point in time, the metal furnaces blew up so often (as frequently as 

two times per week) that the site ran out of pre-cast insulator tiles. An employee made a 

suggestion at the time to use regular fire brick rather than wait for the manufacturer to send in 

pre-formed tiles. This statement was confirmed when the Advisory Board located a record 

stating that the employee had received a $75 award for this suggestion to use fire bricks. After a 

while, they figured out that the shells were being used too often, and that is what was causing a 

weak spot in the liner and causing the metal to go through it and spill all over in the containers. 

Some interviewees indicated that blowouts were not quite as frequent at WS as at Destrehan. 

After a blowout had occurred and things cooled down, the operators had to go in with their 

regular work shoes and clean up the mess, which was a combination of uranium and all kinds of 

slag and garbage. Even after the operators cleaned the furnace up, there was still a lot of material 

in the furnace. After this initial cleanup, the electricians would go into the furnace and rewire it. 

The brick liners also had to be replaced. These explosions and the subsequent clean-up were a 

source of potential uptake of radioactive material. 

H&S would be notified when there was a blowout, and they would go out to the area. As soon as 

H&S was notified, personnel would go to the site of the accident. If it happened in the middle of 

the night, they may not get to it until the next morning. H&S staff would check out the situation, 

monitor the area, search for dust, maybe request special bioassay of the workers involved, and 

find out why it occurred. For example, was the shell recycled too many times? Was there a flaw 

in the magnesium fluoride liner? Every one of these things would have been investigated 

thoroughly. H&S would check for exposures after the incident while workers were in the 

process of or completed with cleaning it up. 

As an additional precaution, burn-outs in element-type furnaces were replaced with Vacuum

Induction Heating, only to result in a disastrous explosion, which occurred in the Recast Furnace 

on July 15, 1960. [Following is the story of this incident as written down by the worker before 

his death.]

The material being processed was uranium. 

The operator informed me the furnace was losing pressure. I purged the furnace 

down according to procedure. When this process was completed I evacuated the 

building in preparation for entering the furnace enclosure. [Another worker] reentered the building and I told him again that he had to leave. [The other 

worker] said that I should not be left there alone. 

I understood that if the furnace lid could be raised three inches, we should be ok. 

[The other worker] knelt on the platform to operate the lid control buttons while I 

stood next to him giving him the necessary hand signals to safely raise the lid. 

After we achieved a height of at least three inches, I turned to [him] and said it 
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looks like we’re ok, I took one step back to enter the furnace enclosure, and that is 

when the furnace blew. 

The lid lifted a short distance, fire shot out around the lid and then the lid 

dropped back down. The concussion hatch in the top of the furnace enclosure 

was blown over to the rotary kiln. I was blown back across the platform where I 

caught [the other worker] and laid him on the platform deck. I began 

administering first aid to [him] who appeared to have major arteries severed. 

There was so much blood that I had trouble tying the tourniquets because 

everything was so slick. I called for help and [one of my operators] approached 

the base of the platform ladder. I asked him to bring me screwdrivers or sticks to 

tighten the tourniquets. [He] returned with some screwdrivers. I was then able to 

apply sufficient pressure to control the bleeding. 

I then dialed station 500, which simultaneously contacted the guard office, 

dispensary and boiler house. I told the guard I had a man down and to send an 

ambulance to take him to St. Joseph Hospital in St. Charles due to the severity of 

his injuries. 

At this time I sent my crew to Barnes Hospital. 

After I secured the area, approximately two hours after the explosion, I agreed to 

go to Barnes Hospital and was refused admittance due to a fear of contamination. 

The treatment I received was being stuck with pins and asked whether I could feel 

it, and being asked if I was contaminated. 

After returning to the plant I was informed my work clothes had been burned and 

that [name](the head of safety) wanted to speak to me. The subsequent discussion 

was recorded. Then [name] wanted to speak to me and I told him to listen to [the 

head of safety’s] recording because I was going home. 

Upon my arrival at home I learned my family heard about the explosion through 

the media. No one at Mallinckrodt bothered to call. 

Later that day my crew and I were called and asked to attend a meeting at the 

plant at 8:00 am the following morning, which was a Saturday. The meeting 

began with tape recorders being turned on and the following statement. “We 

want you to tell us what happened up until the time of the explosion, and what you 

did after the explosion.” At this time, one of my operators, [name] stated the 

following: “Now that we’ve had an explosion you want to know what we did. But 

when [name] kept telling you that the furnace was going to blow you wouldn’t 

pay any attention to him.” The recorders were then turned off and the meeting 

adjourned. 

The family heard about the explosion on the radio. The St. Louis Globe Democrat reported the 

incident as a minor gas explosion. A witness heard the explosion and went over to the induction 

furnace where there were several individuals on the floor. The power was shut down. Nobody 
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got killed, but a lot of people got injured. The nurse that was there was using screw drivers as 

tourniquets. This process was never restored nor put back into production. 

During the machining process of the ingots, there were times when the chips would catch on fire. 

The material cut off the ingots was drummed. Occasionally, one of the drums on the truck 

would catch on fire. The ingots would catch on fire, and they were moved outside and allowed 

to burn out. When it burned itself out, they would pick up the black oxide, and that was it. The 

ingots were burning right out there in the atmosphere. This didn’t occur very often, but it did 

happen. 

At one time, they had a concrete lid on the bomb (steel container) and a batch of recorders 

monitoring the temperatures. When they came to 1,300 degrees, they would get a glitch, and 

they would drop that concrete lid down to contain an explosion in case one occurred. 

RECORDS AND DOCUMENTATION 

WS did not routinely provide workers with the results of their bioassay or film badge monitoring. 

Prior to the Advisory Board meetings concerning the Destrehan Plant, some individuals had 

difficulties getting hold of their exposure records. Workers were told that the records were lost. 

However, at one of the Advisory Board meetings, at the last minute, NIOSH came and said 

everything was solved and that they could reconstruct individual doses. They had located a 

collection of records that suddenly solved the problem. With these records was a letter from 

Mont Mason, the head of the Mallinckrodt Chemical Workers medical and records group. The 

letter said the information was very valuable, provided that it is reconstructed and correlated 

where it makes sense. The Advisory Board directed NIOSH to provide a copy of the cover letter 

to the Destrehan Plant petitioners, because they had been not aware of these documents. 

In Mont Mason’s letter, where he indicated the information was valuable and shouldn’t be lost, 

he also said it should be worked on immediately to coordinate it. Interviewees with records 

experience described the process for tracking and compiling the kinds of data that were 

recovered (e.g., punch card records). These interviewees agree that the average radiation doses 

for departments are valid, but they have concerns about using this data for reconstructing 

individual doses. Their objections are related to concerns about the ability to correlate dose data 

with specific individual workers. This concern about individuals’ records is applicable to both 

Destrehan and Weldon Spring. 

The computer group worked with punch card records, creating average radiation records for the 

different departments and keeping records on the individual workers. These punch cards were a 

part of the records that NIOSH found. Radiation and medical records were kept by various 

forms of identification. Some records were identified just by name (last name and first initial); 

in some cases, different individuals had the same last name and first initial. Some of the records 

were identified by social security number, and other records were identified by five-digit worker 

IDs. These five-digit ID numbers cannot conclusively identify an individual worker, because the 

numbers ran out over time. After the five-digit ID numbers were used up, ID numbers for people 

who left the plant were subsequently reassigned to different workers. 
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Some interviewees have had a very difficult time getting their dose records assessed. Even when 

a worker had extensive records, they encountered road blocks in terms of obtaining and 

completing appropriate forms, or ran into issues with the exchange of dose-related information 

between DOE and NIOSH. 

Some workers suspect there were issues with contaminated records, because the ventilation 

system blew the material into the Administrative Building. There were problems with 

contamination at the site. There were some unclassified documents destroyed towards the end of 

WS. They were taken out and burned onsite. There are witnesses to this activity. 

Some workers were able to obtain radiation monitoring records by requesting them from Oak 

Ridge, Tennessee. However, not all workers or survivors have received the records requested. 

In other cases, there are indications that information is left out of the files received by workers. 

At an Advisory Board meeting, the Ph.D. in charge of dose reconstruction indicated that they 

could do dose reconstruction even though there were so many records missing by using coworker 

data or other data. Workers at WS question this approach, because science should rely on 

accurate data. 

Every operation had a logbook that would contain detailed information about the process. 

Workers recorded times for various steps of the process; receipt of acid, addition of acid, etc. 

Unusual occurrences would also be recorded in the logbook. Anything the workers thought 

should be in it would be written in it. In the case of maintenance, the foreman in the area would 

write a work order. They would bring it over to the Shop Foreman, who would assign the daily 

tasks. 

When safety studies were conducted on the green salt plant, a report documenting this study 

would have been produced. It would describe when the study was done and who performed it. 

Routine monthly H&S reports would document all of the activities conducted. There were 

classified documents related to operations, and in some cases, some material in the H&S reports. 

There was a Document Control group that maintained document inventories and kept track of the 

books and technical reports in the library. Any documents forwarded to this group were tracked. 

Data completeness is a key issue that needs to be dealt with in the site profile. There is some 

information on the number of workers at the site (MCW/WS), but interviewees are not 

convinced that NIOSH has complete information on the total worker population. Without 

definitive knowledge of the population, how can they determine how well the available 

monitoring data actually represent the whole population? 

When they first started discussing MCW, NIOSH was asked to identify what percentage of 

workers had complete records of all internal and external monitoring. After about 2 years, 

NIOSH indicated they had complete records for about 20% of MCW workers (2,542 white 

males). This data was from the Comprehensive Epidemiological Data Resource dataset for the 

MCW Cohort Mortality Study (Dupree-Ellis et al. 2000), which included workers from both WS 

and MCW-Destrehan. The site profile needs to include the sex and race statistics for the MCW 

and WS work forces. It also needs to identify the percentage of the individuals in each race and 
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gender for each facility. The MCW Cohort Mortality Study (Dupree-Ellis et al. 2000) abstract 

reads as follows:

In a study of 2,514 White male workers employed between 1942 and 1966 at a US 

uranium processing plant, mortality was compared with overall US mortality, and 

the relation between external ionizing radiation and cancer was evaluated. 

Through 1993, 1,013 deaths occurred. The mean cumulative dose was 47.8 mSv. 

The standardized mortality ratio (SMR) was 0.90 for all causes of death and 1.05 

for all cancers. Many cancer sites had elevated SMRs. Among nonmalignant 

outcomes, the SMR for chronic nephritis was 1.88 (six deaths observed). An 

excess relative risk estimate of 10.5 per Sv (10 cases) was observed for kidney 

cancer; this may have resulted from chance, internal radiation, or chemical 

exposures not considered. 

Copyright 2000 by The Johns Hopkins University School of Hygiene and Public 

Health, Baltimore, Maryland, USA. All rights reserved.

POST-PRODUCTION ERA 

It is too simplistic to think of the site as a whole when doing dose reconstruction. NIOSH needs 

to consider dose reconstruction in terms of periods of time. 

The uranium production period ended in 1966, with the possibility of some work in 1967. In 

1967, the DOE turned the site over to the Army for making Agent Orange. Did the legal 

ownership transfer from the DOE to the Army? The key word here is ownership. The site 

profile refers to “transfer” that is not equivalent to “transferred ownership” or “transferred the 

deed...” Did the DOE cease to own the facility in 1967? On the federal facility database, the 

coverage excludes the years 1967–1974 (Department of Health and Human Services (HHS) 

energy.gov facilities data), resuming in 1975 and continuing for the remediation period at the 

site. However, the site profile mentions that the Army controlled the site during 1967–1984. 

These two statements need to be reconciled. The AEC/ERDA [Energy Research and 

Development Administration] owned the site. The contamination and equipment were in place 

throughout this period of time. The site profile should investigate the rationale for not covering 

1967–1974. Further re-reading of the site profile reveals an additional lack of clarity regarding 

when the site was transferred back from the Army to DOE; did this happen in 1969, in 1984, or 

at some other time? It is understood that these are DOE questions, but they deserve some 

attention. 

The definition of the covered period in the site profile is confusing. This is because the 

necessary investigative work has not been done on site deed transfers to document land and 

property transfers between AEC/ERDA/DOE, Missouri Conservation Department, Missouri 

Department of Natural Resources (Katy Trail, supervisor), and the Department of Defense 

(DOD). There should be records filed with the county, state, etc., to document the transfer of site 

control and/or ownership to various parties. There are probably piles of documents, including 

letters. What source documents track these property transfers, and where are they located? The 

St. Charles County Recorder of Deeds would probably be the best place to start looking. Yvonne 

Deyo (current Weldon Spring site manager), the Long-Term Surveillance and Maintenance 
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(LTSM) plan section on Institutional Controls, and the DOE Office of Legacy Management 

should all be consulted on this important matter of ownership. [Name], who was formerly 

associated with Weldon Spring Ordnance Work for 16 years, is another highly knowledgeable 

person who could be interviewed about these matters. Dan Brown, head of the St. Charles 

Historical Society, wrote a book titled, Small Glories. During his research, he went through 

newspaper articles related to Weldon Spring and dug out all the legal documents. This book 

describes the land transactions. 

Post-Production Exposure Concerns 

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 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 Weldon Spring site timeline posted at the 

Interpretive Center (document is online) mentions T-S-R. 

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

production buildings. His 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-SR 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 him out of the building and tell him 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 in question now has a burning sensation in his feet and a number of other symptoms. 

These symptoms are similar to those seen following high skin doses of external radiation; the 

condition is well described in the textbook, Radiation Pathology [Fajardo et al. 2001]. It appears 

likely (in a physician’s judgment) that this worker’s symptoms were due to yellow cake-induced 

radiation injury rather than to any pre-existing peripheral vascular disease. The construction 

worker told his story to the state in Jefferson City, Missouri. X-rays were taken, and an 

examination was completed. The worker requested records from this exam, but was told they 

were lost. 

The worker had worn a film badge on his chest, although the exposure source he encountered 

was on or under the floor. The worker did not recall any bioassay having been done for him, and 

he did not receive a dose report based on his film badge reading. This worker had not requested 
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his records from the DOD as of the time when the site expert was interviewed. The site expert 

stated that there should be some high level requesting by Department of Labor (DOL) for records 

collected by DOD. There is a provision in the EEOICPA (section 7384w) to subpoena records. 

The WS site expert suggested that SC&A should interview the worker, who has expressed 

willingness to talk about his Weldon Spring experience. If TSR, Inc. is still in business in 

Denver, they might be a good source of additional information. In addition, the worker 

interacted extensively over 2 years with a reporter and was featured in a series of seven articles 

on MCW-WS published by the St. Louis Post-Dispatch in February, 1989. The reporter and her 

two co-reporters might also be good candidates for interviews in regard to the WS site profile. 

The WS site expert is not aware of anyone who worked at Weldon Spring from 1967–1969 who 

has developed cancer and filed a claim. DOL could easily answer this question, but the Privacy 

Act is used to shield such information from individuals who have a real need to know. For 

example, citizens are not allowed to have a list of employees from the site. Getting this 

information from DOL should be an integral part of investigating Weldon Spring Site (WSS) 

ownership during the “Herbicide/Agent Orange DOD period” and thereafter during the entire 

period that AEC/ERDA/DOE owned WSS. 

The extent of the work that was done from 1975–1986 deserves more elaboration. There was a 

lot going on, and the monitoring program was very active during this period. Some projects 

conducted during that time presented a potential for much larger exposures. Ground water is a 

proxy for what was going on. There were levels of uranium at 12,000 pCi/liter in one well 

(Burgermeister Spring well 6303) used for offsite monitoring. 

In 1983–1984, Bechtel was the general contractor responsible for the WS quarry and raffinate 

pits. The site profile referred to this as the site monitoring period. In order to do an adequate 

job, they had to do a finer grain analysis. Raffinate Pit 4 developed a leak, and the contaminated 

sludge spilled over into the Department of Conservation land. Bechtel hired Banghart [may be 

spelled Bangart] Brothers Company (a trucking Company); their workers went down in the 

raffinate sludge. Although they had a contract with Bechtel, the trucking company 

(subcontractor to Bechtel) would not admit employment during this time. A platform with a 

shower head was built, which was very unusual. On this particular job, a crew of three to four 

guys stayed in the same area the entire time, which was unusual. They wore workman’s clothes, 

boots, and light gloves. They did not wear respirators, and they were not monitored during this 

time period. 

SITE PROFILE/DOSE RECONSTRUCTION COMMENTS 

There are a number of deficiencies in the Weldon Spring site profile: 

(1) MULTIPLE URANIUM METAL AND URANIUM METAL ALLOYS WERE 

PRODUCED AT WELDON SPRING. It has become clear that the uranium metal source 

terms at Weldon Spring and the processing done to the billets and dingots have not been 

accurately and fully characterized. Interviewees intend to transmit this information in 

more detail to the TBD-6000 work group. The dimensions, weight, and exact chemical 

composition of each of these metallic forms needs to be described in detail, in order to 
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assign a correct radiation dose to those handling the forms with widely varying 

geometries. 

(2) THE URANIUM METALLURGY EQUIPMENT TO PRODUCE THE VARIOUS 

PURE URANIUM AND URANIUM ALLOY FORMS WAS NOT ADEQUATELY 

DESCRIBED. The WS site profile mentions that alpha and gamma phase extrusion of 

uranium metal billets took place. It is not clear whether all or some of the gamma phase 

extrusion took place at the St. Charles facility. It is known that the AEC contract 

between MCW and Dow Chemical during 1957–1960 was, in part, for gamma phase 

R&D extrusion of uranium metal at Dow Chemical in Madison, Illinois. It is apparent 

from the WS profile that uranium extrusion was a cost center, implying that WS 

possessed extrusion presses. The physical characteristics (tonnage, manufacturer, year 

installed, etc.) do not appear to be described in the WS site profile. Whether or not the 

extrusion press(es) had vacuum accessories to collect the uranium dust during operation 

is very important to calculating operator radiation doses. Some such extrusion equipment 

had vacuum attachments, whereas some (e.g., Dow Madison plant) did not. Operators of 

extrusion presses that lacked vacuum accessories would receive high dust inhalation 

doses compared to operators of presses that were equipped with vacuums. 

(3) NON-DESTRUCTIVE TESTING (NDT) AND NDT TESTING EQUIPMENT USED 

AT WELDON SPRING WAS INCOMPLETELY DESCRIBED. The statement can be 

supported that any and all facilities that produced heavy metal castings, extrusions, 

welded forms, and rolled products needed to be inspected by NDT methods. Ultrasonic 

testing is only briefly described in the WS site profile. Due to the high density of 

uranium metal, gamma photon (Co-60, Ir-192) or x-ray (Betatron, flash x-ray) 

radiography would be necessary to penetrate and image it. The same would be true for 

thorium metal products. The site profile should contain a complete description of all 

equipment used to cast, roll, extrude, or machine uranium and thorium metal, because 

operators of such equipment would be exposed to residual radioactivity of the equipment 

they operated. Job descriptions and Cost Center allocations of such jobs should also be 

recorded in the appropriate site profile tables. 

(4) CONTRACT WORK WITH GSI AND DOW-MADISON ARE POORLY DESCRIBED 

AND DOCUMENTED IN THE SITE PROFILE. It is known that MCW had an AEC 

contract with General Steel Industries (GSI) to provide high energy (24–25 Mev) x-ray 

services as part of the MCW Uranium Division quality control program. However, the 

site profile section on WS NDT subcontractor work at GSI between 1957 and 1966 is 

very weak. No contract records have survived or been recovered at DOE except some 

relevant purchase orders from 1958 to 1966 (Considered Sites Database). Vital records, 

such as NDT technical reports, shipping manifests to GSI and Dow in Illinois, GSI 

Betatron shot records, and inspection reports in the form of Betatron x-ray interpretations 

have all been lost. Such information should be included in the WS site profile. 

In particular, more detail is needed regarding subsequent handling of uranium that came 

back to the site after Betatron irradiation. When heavy metals (including U-238 and 

Th-232) are exposed to a 24–25 MeV beam, there is activation and some production of 
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fission products. Some of the fission products and radioactive daughters have longer 

half-lives than 15 minutes. Worker exposures would depend on how quickly the 

Betatron-irradiated uranium was turned around and returned to WS. Weldon Spring was 

aiming for 100% purity when they cast uranium metal, but they actually achieved 97%–

99% purity. There was also experimental work going on related to alloying of uranium 

[see Leaders et al. 1953 and Weakley 1963]. 

Workers are disenchanted with the dose reconstruction and compensation program for several 

reasons: 

• Many former workers take exception to the dose reconstruction process, because they 

feel there isn’t enough data. NIOSH needs to be using factual data rather than estimates. 

They create a process based on presumptions rather than facts. In some cases, NIOSH 

used surrogate data to determine a claimant’s exposure. Some individuals continue to 

have difficulty finding records of their employment at facilities. 

• It has taken a very long time to reach the point of denial. There are people who are alive 

and probably could use the money for medical expenses, but they are not getting it, 

because it is taking so long. 

• NIOSH has given the benefit of the doubt to the company rather than the claimant. These 

individuals are low on the totem pole in terms of response to their needs. It is 

incomprehensible how you can spend $900 million to clean up a site, just in case it might 

be dangerous, and then tell the workers they have to prove they were exposed to 

something dangerous. 

• Even when a claimant gets paid, many doctors will not accept the medical card. Doctors 

say there is too much red tape in the program. 

NIOSH has not improved the dose reconstruction process through input provided by workers. 

There has been no formal response provided to some attendees at the WS worker outreach 

meeting. NIOSH could do a lot better in responding to former worker concerns. They seem to 

take the information and not do anything with it, especially not in a timely manner. 

There were four to five meetings about MCW. A major fraction of the individuals who talked 

worked at both locations [Destrehan and WS]. There were two outreach meetings held by 

NIOSH representatives. The write-up of these meetings that was released as the public record is 

very poor and incomplete. These meetings were video taped. NIOSH needs to be producing 

verbatim transcripts. 

MISCELLANEOUS COMMENTS 

• Workers were exposed to chemicals, such as nitric acid, sulfuric acid, beryllium, 

magnesium, arsenic, asbestos, chromium, ionium, and uranium. There were problems 

with workers getting burns by walking by the nitric acid because of the fallout coming 

out of the gas stacks. Workers also complained about their eyes watering in certain areas. 
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• Workers wore rubber gloves in the green salt plant, where there was danger of 

hydrofluoric acid exposure. Strong acid would produce a noticeable burning sensation, 

but weak acid could remain on the skin for up to 8 or 9 hours without the worker 

knowing it was there. One worker exposed his finger to a strong acid and when he got 

home, his finger started to tingle. He called the plant and they sent him down to the 

hospital. He suspected he had cross-contaminated his finger when he picked up the glove 

to dispose of it. There was an area about 3/8 inch were it was eaten down. Another 

worker had his fingers eaten off from acid. 

• Dust collected on the insulators and wood cross-arms of the high lines, causing the high 

voltage power lines to short out. 

• In one accident, hydrochloric acid dust hit the transformers of the metal building and 

blew up the transformer substation. 

• Solvents from the plant were recycled. 

• Interviewees reported overtime ranging from none to as much as 8 hours per day in some 

cases. The amount of overtime depended on the worker’s position and whether or not 

operations were proceeding smoothly. If there was an event, there was a higher chance 

of overtime. 

• While employees waited for their security clearances to come through, they were 

sometimes located at the Destrehan Plant. 

• At one point, an automatic attendance system was installed at WS. Badges with holes in 

them were put into a reader to record the badge number, and a key punch punched the 

badge number into IBM cards. This allowed the plant to compute the attendance for 

plant personnel. 

• Fernald and Weldon Spring were the same kind of plant. The H&S operations at WS and 

Fernald were influenced by those at the Destrehan Facility. 

• Costs and cash flow influenced the extent of monitoring and the enforcement of safety 

practices. If the plant was losing too much production, the onus was put on the employee 

to follow through with appropriate safety measures. This was why the same lax 

procedures were brought from Destrehan out to WS. 

• MCW had a private plant in Hematite, Missouri, where they processed enriched uranium. 

They had a series of pipes that processed the material. That process was prone to 

explosions and other problems. There was no collaboration between Hematite and WS. 

• Diseases observed in WS workers have included Leiomyosarcoma, colon cancer, breast 

cancer, adenocarcinoma of the bile duct, and other rare cancers. There are also 

individuals who suffer from decreased oxygen supply. 
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• Members of the WS staff visited various DOE sites (i.e., Oak Ridge National Laboratory, 

Y-12, K-25, Savannah River, and Hanford) throughout the country. One former worker 

was present at Nevada Test Site on two occasions, in the trenches (8-foot high) half a 

mile away from the atomic blasts. Individuals in this location wore a steel helmet and sat 

down on the ground. After they saw the blinding white light, they stood up on a platform 

and looked down to see the earth popping as the blast came towards them. Then they 

heard a noise. This worker was also sent to military storage sites. 

OTHER MCW FACILITIES (DESTREHAN STREET AND LATTY AVENUE) 

In the metals area at Destrehan Plant, a worker could be walking along and hit a piece of 

uranium with his shoe. The uranium would just skip on concrete and make fire. When cleaning 

ingots in the break-out area, workers wore rubber gloves; they would reach in with a covered 

shield and break it with sledge hammers. When the ingot dropped out, a lot of times a spark 

would get on top of the ingot down below on the conveyor where they hauled it away. That stuff 

would lay on that conveyor for a couple of hours or so. There was a black oxide and it would 

ignite and turn red. It would just burn away. 

At Destrehan Plant, there were a lot of times when the furnaces would blow out and fill half of 

the building. 

At the time when Destrehan was operating, the uranium metal dropped into a vessel about 8–

9 inches high and about 10 inches in diameter. It was called a derby. The derbies were sent 

elsewhere to be forged into rods. WS was set up to be a more efficient process. 

As far as the workers knew they were working on something pretty safe. They would have a 

safety meeting and they would come in at Destrehan and tell workers they had to find something 

wrong. This was more or less a joke. 

At Destrehan, they had a building called 7E. They were manufacturing plutonium, and people 

were saying it was for the H bomb. In this particular building, the contamination control was 

tighter. Tools taken into the building could not be removed. When a worker exited the area, 

they had to check their hands. If the worker got a certain reading, they had to go over and scrub 

their hands and then recheck them. 

At the Destrehan plant, they referred to “the place across the street.” If you had to go into that 

area to work on a pump, you had to dip your tools in neutralizer and put them in a barrel. They 

were hauled out to the airport to the raffinate pit. 

Bioassay monitoring and air sampling were not routine at Destrehan. 

At Destrehan, when they had raffinate, they trucked it out to Latty Avenue by the airport, and 

they dumped that stuff right there. On several occasions, the waste came out of a particular 

building where it had been dumped into something like a big swimming pool. Stuff started 

coming out of there. Coldwater Creek went right through there; when we had a big rain, that 

stuff would go down into Coldwater Creek. The material was transported from Destrehan to 

Latty Avenue in regular dump trucks. If they put any type of liner in there, it was like paper, and 
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stuff was visibly dripping out as the truck went down the road to the Latty Avenue site. They 

kept this up for a number of years. Sometimes they would go out to Latty Avenue, pick the 

material up, and bring it back to Destrehan to rerun it again. 

Latty Avenue runs into Airport Road and Banshee Road that run right across Boeing. One time, 

over on the airport side, they built Building 66 for Boeing. They transported the excavated dirt 

over to Latty Avenue and dropped it in there. Apparently, some kids made a baseball field out of 

the area, and a couple of kids were not feeling right. The stuff had dried out and the wind carried 

it off. 

There was a burial site at the St. Louis airport. They transported barrels in trucks down to the 

airport for burial. There was a dirt pile by the airport containing this waste. They have moved 

the pile to Berkley, Missouri. Prior to moving the pile, they sent crews of laborers down to dig 

up the radioactive material. Security personnel who were there on a rotational basis were 

monitored, but the laborers doing the digging were not monitored. The radiation level was very 

high. 

REFERENCES 

DuPree-Ellis, E., Watkins, J., Ingle, J.N., and Phillips, J., 2000. “MCW Cohort Mortality 

Study,” American Journal of Epidemiology, 152(1):92-95, July 1, 2000. 

Fajardo, L.F., Bethrong, M., and Anderson, R.E., 2001, Radiation Pathology, Oxford University 

Press. January 2001. 

Leaders, W.M., et al., 1953. Process Development Quarterly Report, Part II, NYO-1358, 

Mallinckrodt Chemical Workers, St. Louis, Missouri. October 15, 1953. 

[Name redacted], 2005. Statement in Support of the Advisory Board of Radiation and Worker 

Health Approving the MCW 1949–1957 Class SEC00012-2 Petition, Advisory Board on 

Radiation and Worker Health, Cedar Rapids, Iowa. April 25–27, 2005. 

ORAUT (Oak Ridge Associated Universities Team) 2005. Basis for the Development of an 

Exposure Matrix for Mallinckrodt Chemical Workers St. Louis Downtown Site and the St. Louis 

Airport Site, Missouri: Period of Operation 1942-1958, ORAUT-TKBS-0005, Rev. 01. Oak 

Ridge Associated Universities, Cincinnati, Ohio. March 10, 2005. 

Weakley, E.A., 1963. Status of Alloyed Dingot Program, January 1963, HW-73149, Hanford 

Engineering Works. January 11, 1963.