November 2017

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 – November 2017

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

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.
Weldon Spring Site Profile Findings Matrix 3 SC&A – November 2017

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

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.
Weldon Spring Site Profile Findings Matrix 4 SC&A – November 2017

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

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 TBD4, 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 

September 20, 

2017, to WS WG 

that this finding 

has been resolved. 

SC&A 

recommends that 

this finding be 

closed.
Weldon Spring Site Profile Findings Matrix 5 SC&A – November 2017

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

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.
Weldon Spring Site Profile Findings Matrix 6 SC&A – November 2017

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

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 

OTIB-0079 and 

OTIB-0006. Later 

revision to TBD-3 

provides 

clarification of the 

issue.

SC&A 

recommends that 

this finding be 

closed.
Weldon Spring Site Profile Findings Matrix 7 SC&A – November 2017

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

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 

OTIB-0079 and 

OTIB-0006. Later 

revision to TBD-3 

provides 

clarification of the 

issue.

SC&A 

recommends that 

this finding be 

closed.
Weldon Spring Site Profile Findings Matrix 8 SC&A – November 2017

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

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 

OTIB-0079 and 

OTIB-0006. Later 

revision to TBD-3 

provides 

clarification of the 

issue.

SC&A 

recommends that 

this finding be 

closed.
Weldon Spring Site Profile Findings Matrix 9 SC&A – November 2017

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

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 

OTIB-0079 and 

OTIB-0006. Later 

revision to TBD-3 

provides 

clarification of the 

issue. 

SC&A 

recommends that 

this finding be 

closed.

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.
Weldon Spring Site Profile Findings Matrix 10 SC&A – November 2017

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

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.

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.
Weldon Spring Site Profile Findings Matrix 11 SC&A – November 2017

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

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.

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 (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.
Weldon Spring Site Profile Findings Matrix 12 SC&A – November 2017

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

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.

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.
Weldon Spring Site Profile Findings Matrix 13 SC&A – November 2017

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

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.

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.
Weldon Spring Site Profile Findings Matrix 14 SC&A – November 2017

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

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.

No further action 

has been received 

for this item. 

Therefore, it is 

still open.

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.
Weldon Spring Site Profile Findings Matrix 15 SC&A – November 2017

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

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 costcenter information; some may contain job titles, or work locations.

It was stated during 

the 1/25/2011 WS 

WG meeting that the 

cost-center code 

would not be used 

for DR. This issue 

was resolved and 

closed (transcript 

page 266).

Closed.
Weldon Spring Site Profile Findings Matrix 16 SC&A – November 2017

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.
Weldon Spring Site Profile Findings Matrix 17 SC&A – November 2017

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

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 claimantfavorable 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. 

This finding is 

open.

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.
Weldon Spring Site Profile Findings Matrix 18 SC&A – November 2017

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

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. 

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.
Weldon Spring Site Profile Findings Matrix 19 SC&A – November 2017

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.