February 1, 2018

DISCLAIMER; This is a working document provided by the Centers for Disease Control and Prevention (CDC) technical support contractor, SC&A, for use in 

discussions with the National Institute for Occupational Safety and Health (NIOSH) and the Advisory Board on Radiation and Worker Health (ABRWH), including its 

Working Groups or Subcommittees. Documents produced by SC&A, such as memorandum, white paper, draft or working documents are not final NIOSH or ABRWH 

products or positions, unless specifically marked as such. This document prepared by SC&A represents its preliminary evaluation on technical issues. 

NOTICE: This document has been reviewed to identify and redact any information that is protected by the Privacy Act 5 USC §552a and has been cleared for 

distribution. 

WELDON SPRING PLANT SITE PROFILE FINDINGS MATRIX

TBD 

Finding 

No.

Finding Resolution by 

NIOSH/SC&A/WG Status

1 Lack of Personnel Contamination and Egress Monitoring 

The Weldon Spring (WS) site technical basis documents (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 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.

This issue will be 

addressed on a caseby-case basis 

according to DCASTIB-0013.

After discussion 

during the May 9, 

2011, WS Work 

Group (WG) 

meeting, the finding 

was resolved and it 

was recommended 

to close this finding. 

Finding was closed 

by the WG, page 

229 of transcript.
Weldon Spring Site Profile Findings Matrix 2 SC&A – February 1, 2018

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TBD 

Finding

No.

Finding Resolution by 

NIOSH/SC&A/WG Status

2 Inadequate Information Concerning Workers Status and Exposures for 1967–1984 

The WS site TBDs do not explicitly state when U.S. Department of Energy (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 led to incidences of skin 

contamination, inhalation, and ingestion of radioactive materials (including uranium and 

thorium, as well as radionuclides contained in the raffinate concentrates and its scale/soil that 

had been resuspension) that were not monitored 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.

This issue will be 

addressed on a caseby-case basis if cases 

come up; so far no 

claims for this period.

After discussion 

during the May 9, 

2011, WS WG 

meeting, the finding 

was resolved and it 

was recommended 

to close this finding. 

Finding was closed 

by the WG, page 

226 of transcript.

3 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.

The potential exposure 

to other radionuclides 

of concern has been 

addressed in other 

findings for WS. 

Therefore, this issue 

has been addressed.

SC&A recommends 

that this finding be 

closed.

Closed by WS WG 

2/1/2018.
Weldon Spring Site Profile Findings Matrix 3 SC&A – February 1, 2018

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TBD

Finding 

No.

Finding Resolution by

NIOSH/SC&A/WG Status

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 Special Exposure Cohort (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.

The WS TBDs have 

been revised to 

include RU and 

associated 

radionuclides with the 

correct dates of usage 

at WS.

SC&A sent email of 

September 20, 

2017, to WS WG 

that this finding has 

been resolved. 

SC&A recommends 

that this finding be 

closed.

Closed by WS WG 

2/1/2018.
Weldon Spring Site Profile Findings Matrix 4 SC&A – February 1, 2018

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TBD 

Finding 

No.

Finding Resolution by 

NIOSH/SC&A/WG Status

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 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 an 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.

This issue was 

discussed at the 

9/13/2011 WS WG 

meeting. NIOSH 

provided information 

and clarification. 

SC&A agreed that the 

issue was resolved 

(page 136 of 

transcript).

SC&A recommends 

that this finding be 

closed.

Closed by WS WG 

2/1/2018.
Weldon Spring Site Profile Findings Matrix 5 SC&A – February 1, 2018

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TBD 

Finding 

No.

Finding Resolution by 

NIOSH/SC&A/WG Status

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 

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.

Resolution to this 

issue was discussed at 

the 1/25/2011 WS WG 

meeting (transcript 

pages 250–258) and is 

addressed by 

recommendations and 

guidelines in OTIB0079 and OTIB-0006. 

Later revision to TBD3 provides 

clarification of the 

issue.

SC&A recommends 

that this finding be 

closed.

Closed by WS WG 

2/1/2018.

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. 

ORAUT-OTIB-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.

Resolution to this 

issue was discussed at 

the 1/25/2011 WS WG 

meeting (transcript 

pages 250–258) and is 

addressed by 

recommendations and 

guidelines in OTIB0079 and OTIB-0006. 

Later revision to TBD3 provides 

clarification of the 

issue.

SC&A recommends 

that this finding be 

closed.

Closed by WS WG 

2/1/2018.
Weldon Spring Site Profile Findings Matrix 6 SC&A – February 1, 2018

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TBD 

Finding

No.

Finding Resolution by 

NIOSH/SC&A/WG Status

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-OTIB-0006 (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.

Resolution to this 

issue was discussed at 

the 1/25/2011 WS WG 

meeting (transcript 

pages 250–258) and is 

addressed by 

recommendations and 

guidelines in OTIB0079 and OTIB-0006. 

Later revision to TBD3 provides 

clarification of the 

issue.

SC&A recommends 

that this finding be 

closed.

Closed by WS WG 

2/1/2018.

9 Use of ICRP-34 Instead of ICRP-74 

TBD-3 (ORAUT 2005c) utilizes International Commission on Radiological Protection (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.

Resolution to this 

issue was discussed at 

the 1/25/2011 WS WG 

meeting (transcript 

pages 250–258) and is 

addressed by 

recommendations and 

guidelines in OTIB0079 and OTIB-0006. 

Later revision to TBD3 provides 

clarification of the 

issue. 

SC&A recommends 

that this finding be 

closed.

Closed by WS WG 

2/1/2018.
Weldon Spring Site Profile Findings Matrix 7 SC&A – February 1, 2018

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TBD

Finding 

No.

Finding Resolution by 

NIOSH/SC&A/WG Status

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 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. 

TBD-4, Rev. 01, of 

5/17/2013 added data 

for assigning 

environmental intakes 

with accompanying 

text for dose 

reconstruction (DR)

(summary of additions 

on page 2 of Rev. 01). 

This issue has been 

resolved.

SC&A recommends 

that this finding be 

closed.

Closed by WS WG 

2/1/2018.

11 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.

TBD-4, Rev, 01, of 

5/17/2013 added data 

for assigning 

environmental intakes 

with accompanying 

text for DR (summary 

of additions on page 2 

of Rev. 01). This issue 

has been resolved.

SC&A recommends 

that this finding be 

closed.

Closed by WS WG 

2/1/2018.
Weldon Spring Site Profile Findings Matrix 8 SC&A – February 1, 2018

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TBD 

Finding 

No.

Finding Resolution by 

NIOSH/SC&A/WG Status

12 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. 

TBD-4, Rev. 01, of 

5/17/2013 added data 

for assigning 

environmental intakes 

with accompanying 

text for DR (summary 

of additions on page 2 

of Rev. 01). This issue 

has been resolved.

SC&A recommends 

that this finding be 

closed.

Closed by WS WG 

2/1/2018.

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.

TBD-4, Rev. 01, of 

5/17/2013 added data 

for assigning 

environmental intakes 

with accompanying 

text for DR (summary 

of additions on page 2 

of Rev 01). This issue 

has been resolved.

SC&A recommends 

that this finding be 

closed.

Closed by WS WG 

2/1/2018.

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, Ra226 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 

(ORAUT 2005e, page 14).

Revised TBD-4, Rev.

01, of 5/17/2013 

added tables and data 

on pages 19–22 to 

resolve this issue.

SC&A recommends 

that this finding be 

closed.

Closed by WS WG 

2/1/2018.
Weldon Spring Site Profile Findings Matrix 9 SC&A – February 1, 2018

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TBD 

Finding 

No.

Finding Resolution by

NIOSH/SC&A/WG Status

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.

Revised TBD-4, Rev.

01, of 5/17/2013, page 

10, added information 

that corrected this 

issue.

SC&A recommends 

that this finding be 

closed.

Closed by WS WG 

2/1/2018.

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 2,000 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.

TBD-4, Rev. 1, of 

5/17/2013, Section 4.3 

uses WS data instead 

of Fernald data. This 

issue has been 

resolved.

SC&A recommends 

that this finding be 

closed.

Closed by WS WG 

2/1/2018.

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 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.

This issue was 

discussed at the 

9/13/2011 WS WG 

meeting. NIOSH 

provided information 

and clarification. 

SC&A agreed that this 

issue along with 

incidents was resolved 

(page 136 of 

transcript).

SC&A recommends 

that this finding be 

closed.

Closed by WS WG 

2/1/2018.
Weldon Spring Site Profile Findings Matrix 10 SC&A – February 1, 2018

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TBD

Finding

No.

Finding Resolution by 

NIOSH/SC&A/WG Status

18 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. 

TBD-5, Rev. 2, of 

5/21/2013, Section 

5.2.2 provides data to 

resolve this issue.

SC&A recommends 

that this finding be 

closed.

Closed by WS WG 

2/1/2018.

19 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 recommended 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.

This issues and the 

proposed radon model 

was discussed at 

several of the WS WG 

meeting. During the 

6/7/2012 meeting 

(transcript page 69), it 

was stated that the 

proposed radon model 

would be brought 

before the AB at the 

next meeting.

Since the previous 

WG discussions on 

this issue, NIOSH has 

revised TBD-4 to 

increase the 

equilibrium factor 

from 0.5 to 0.7. 

SC&A finds this value 

conservative and 

recommends closing 

this finding. Email to 

WG 12/6/2017. This 

response has been 

entered into the BRS 

(12/06/2017). 

2/1/2018: NIOSH will 

include 0.5 to 0.7 

factor in PER.

Closed by WS WG 

2/1/2018.
Weldon Spring Site Profile Findings Matrix 11 SC&A – February 1, 2018

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TBD 

Finding 

No.

Finding Resolution by 

NIOSH/SC&A/WG Status

20 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. 

This issue was 

discussed during the

1/25/2011 WS WG 

meeting. The most 

claimant favorable 

solubility type will be 

used. Finding closed 

(transcript page 240). 

Included in text of 

TBD-5, Rev. 02, 

page16. 

Closed.

21 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. 

This issue was 

discussed and resolved 

during the 5/9/2011 

WS WG and it was 

closed (transcript page 

185).

Closed.

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 may contain job titles, or work locations.

It was stated during 

the 1/25/2011 WS WG 

meeting that the costcenter code would not 

be used for DR. This 

issue was resolved and 

closed (transcript page 

266).

Closed.
Weldon Spring Site Profile Findings Matrix 12 SC&A – February 1, 2018

NOTICE: This document has been reviewed to identify and redact any information that is protected by the Privacy Act 5 USC §552a and has been cleared for distribution.

TBD

Finding 

No.

Finding Resolution by 

NIOSH/SC&A/WG Status

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 

in-vivo thorium measurements in 1966. On page 29, it 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.

It was stated during 

the 1/25/2011 WS WG 

meeting that these 

results would not be 

used for DR. This 

issue was resolved and 

closed (transcript page 

266).

Closed.

24 Enriched Uranium Not Sufficiently Addressed 

TBD-5 (ORAUT 2005e) discusses enriched uranium (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.

TBD-5, Rev. 03 of 

3/14/2017, uses an EU 

of 1%, which 

increases the 

concentration from 

0.783 pCi/ug to 0.973 

pCi/ug. Therefore, a 

PER is required.

As per NIOSH 

email of 10/4/2017, 

a PER will be 

issued to increase 

the intake from EU. 

2/1/2018: NIOSH is 

in process of 

issuing PER for 

specific activity 

increase.

Closed by WS WG 

2/1/2018.
Weldon Spring Site Profile Findings Matrix 13 SC&A – February 1, 2018

NOTICE: This document has been reviewed to identify and redact any information that is protected by the Privacy Act 5 USC §552a and has been cleared for distribution.

TBD 

Finding 

No.

Finding Resolution by 

NIOSH/SC&A/WG Status

25 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. 

Revised TBD-6, Rev.

01, of 2/6/2013 added 

Section 6.3.11, page 

30, that discuss 

geometry factors and 

references DCAS0013.

SC&A email of 

6/13/2017 to WS 

WG that issue has 

been resolved and 

recommended that 

finding be closed.

Closed by WS WG 

2/1/2018.

26 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

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. 

In NIOSH’s 11/9/2011 

reply to WS Site 

Profile/SEC issues this 

is explained in detail 

on page 17, followed 

by revised text in 

TBD-6, Section 6.3.7, 

page 28 of Rev. 01 of 

2/6/2013. This issue 

has been resolved.

SC&A recommends 

that this finding be 

closed. 

Closed by WS WG 

2/1/2018.

27 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.

TBD-6, Rev. 01 of 

2/6/2013 revised Table 

6-7 and added Table 

6-8 to resolve the 

issue.

SC&A recommends 

that this finding be 

closed.

Closed by WS WG 

2/1/2018.
Weldon Spring Site Profile Findings Matrix 14 SC&A – February 1, 2018

NOTICE: This document has been reviewed to identify and redact any information that is protected by the Privacy Act 5 USC §552a and has been cleared for distribution.

TBD

Finding 

No.

Finding Resolution by

NIOSH/SC&A/WG Status

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.

This issue was 

discussed during the 

9/13/2011 WS WG 

meeting (transcript 

95–134) and SC&A 

evaluated results and 

sent email to WG 

9/20/2011 that the 

issue had been 

resolved and could be 

closed.

SC&A recommends

that this finding be 

closed.

Closed by WS WG 

2/1/2018.