Draft

Advisory Board on Radiation and Worker Health

National Institute for Occupational Safety and Health

A Review of NIOSH’s Program Evaluation Report 

DCAS-PER-083, “Weldon Spring Plant TBD Revision” 

Contract No. 75D30119C04183

Document No. SCA-TR-2023-PER083, Revision 1 

Prepared by

Ron Buchanan, PhD, CHP

SC&A, Inc.

2200 Wilson Blvd., Suite 300

Arlington, VA 22201-3324

September 22, 2023 

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 report has been reviewed to identify and redact any information that is protected 

by the Privacy Act 5 U.S.C. § 552a and has been cleared for distribution.
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SC&A, Inc. technical support for the Advisory Board on Radiation and Worker Health’s 

review of NIOSH dose reconstruction program

Document title A Review of NIOSH’s Program Evaluation Report DCAS-PER-083, 

“Weldon Spring Plant TBD Revision”

Document number SCA-TR-2023-PER083

Revision number 1 (Draft)

Supersedes 0 (Draft)

Effective date September 22, 2023

Task manager Kathleen Behling [signature on file]

Project manager Bob Barton, CHP [signature on file]

Document reviewer(s) Bob Barton, CHP [signature on file]

Record of revisions

Revision number Effective date Description of revision

0 (Draft) 8/10/2023 Initial issue

1 (Draft) 9/22/2023

Revision issued to expand SC&A’s subtask 2 

evaluation of the revised Weldon Spring TBD-4 and 

TBD-5 described in section 4.
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Table of Contents

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

1 Statement of Purpose............................................................................................... 5

2 Relevant Background Information Pertaining to Facility Operations, Potential 

Source Terms, and Worker Monitoring Protocols..................................................... 6

2.1 Facility operations .............................................................................................. 6

2.2 Source terms...................................................................................................... 6

2.3 Internal monitoring ............................................................................................. 7

2.4 External and ambient monitoring........................................................................ 8

3 Subtask 1: Identify the Circumstances that Necessitated DCAS-PER-083 .............. 9

3.1 Chronology of events that necessitated PER-083.............................................. 9

3.2 SC&A’s comments ............................................................................................. 9

4 Subtask 2: Assess NIOSH’s Specific Methods for Corrective Action...................... 12

4.1 Overview of SC&A’s review of Weldon Spring site profile................................ 12

4.2 SC&A’s comments ........................................................................................... 12

5 Subtask 3: Evaluate the PER’s Stated Approach for Identifying the Number of DRs 

Requiring Reevaluation of Dose............................................................................. 13

5.1 NIOSH’s selection criteria ................................................................................ 13

5.2 SC&A’s comments ........................................................................................... 14

6 Subtask 4: Conduct Audits of a Sample Set of Reevaluated DRs Mandated by 

DCAS-PER-083...................................................................................................... 15

7 References ............................................................................................................. 16
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Abbreviations and Acronyms

ABRWH, Board Advisory Board on Radiation and Worker Health 

AEC U.S. Atomic Energy Commission

Bq becquerel

Bq/g becquerel per gram

DCAS Division of Compensation Analysis and Support 

DoD U.S. Department of Defense

DOE U.S. Department of Energy 

DOL U.S. Department of Labor 

DR dose reconstruction 

EEOICPA Energy Employees Occupational Illness Compensation Program Act 

EU enriched uranium 

IREP Interactive RadioEpidemiological Program 

Np neptunium 

NIOSH National Institute for Occupational Safety and Health

NOCTS NIOSH Claims Tracking System

ORAUT Oak Ridge Associated Universities Team

PER program evaluation report 

pCi/mg picocurie per milligram

pCi/μg picocurie per microgram 

POC probability of causation 

Pu plutonium 

Ra radium 

Rn radon 

RU recycled uranium

SEC Special Exposure Cohort 

TBD technical basis document

Tc technetium

Th thorium 

U uranium 

WSP Weldon Spring Plant 

WSRP Weldon Spring Raffinate Pits 

WSQ Weldon Spring Quarry 
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1 Statement of Purpose

To support dose reconstruction (DR), the National Institute for Occupational Safety and Health 

(NIOSH) and the Oak Ridge Associated Universities Team (ORAUT) assembled a large body of 

guidance documents, workbooks, computer codes, and tools. In recognition of the fact that all of 

these supporting elements in DR may be subject to revisions, provisions exist for evaluating the 

effect of such programmatic revisions on the outcome of previously completed DRs. Such 

revisions may be prompted by document revisions due to new information, misinterpretation of 

guidance, changes in policy, and/or programmatic improvements.

A program evaluation report (PER) provides a critical evaluation of the effects that a given issue

or programmatic change may have on previously completed DRs. This includes a qualitative and 

quantitative assessment of potential impacts. Most important in this assessment is the potential 

impact on the probability of causation (POC) of previously completed DRs with POCs less than 

50 percent.

On February 16, 2023, the Advisory Board on Radiation and Worker Health (Board) tasked 

SC&A to review DCAS-PER-083, “Weldon Spring Plant TBD Revision” (NIOSH, 2019; 

“PER-083”). In conducting a PER review, SC&A is committed to perform the following five 

subtasks, each of which is discussed in this report:

• Subtask 1: Assess NIOSH’s evaluation and characterization of the issue addressed in the 

PER and its potential impacts on DR. Our assessment intends to ensure that the issue was 

fully understood and characterized in the PER.

• Subtask 2: Assess NIOSH’s specific methods for corrective action. When the PER 

involves a technical issue that is supported by documents (e.g., white papers, technical 

information bulletins, procedures) that have not yet been subjected to a formal SC&A 

review, subtask 2 will include a review of the scientific basis and/or sources of 

information to ensure the credibility of the corrective action and its consistency with 

current/consensus science. Conversely, if such technical documentation has been 

formalized and previously subjected to a review by SC&A, subtask 2 will simply provide 

a brief summary and conclusion of this review process.

• Subtask 3: Evaluate the PER’s stated approach for identifying the universe of potentially 

affected DRs and assess the criteria by which a subset of potentially affected DRs was 

selected for reevaluation. The second step may have important implications where the 

universe of previously denied DRs is very large and, for reasons of practicality, NIOSH’s 

reevaluation is confined to a subset of DRs that, based on their scientific judgment, have 

the potential to be significantly affected by the PER. In behalf of subtask 3, SC&A will 

also evaluate the timeliness of the completion of the PER.

• Subtask 4: Conduct audits of DRs affected by the PER under review. The number of 

DRs selected for audit for a given PER will vary. (It is assumed that the Board will select 

the DRs and the total number of DR audits for each PER.)

• Subtask 5: Prepare a written report that contains the results of DR audits under 

subtask 4, along with our review conclusions.
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2 Relevant Background Information Pertaining to Facility Operations, 

Potential Source Terms, and Worker Monitoring Protocols

The following information was obtained from the most current revisions of the Weldon Spring 

technical basis documents (TBDs) to present the relevant background for this report. Older 

versions of the TBDs will be referred to as applicable in the appropriate sections for PER-083.

2.1 Facility operations

The facilities covered under the Energy Employees Occupational Illness Compensation Program 

Act (EEOICPA) are the Weldon Spring Plant (WSP), Weldon Spring Quarry (WSQ), and the 

Weldon Spring Raffinate Pits (WSRP). In this document, the term “WSP site” is used where it is 

unnecessary to distinguish between the plant, the quarry, and the raffinate pits. The WSP site was 

operated for the U.S. Atomic Energy Commission (AEC) as a feed materials plant to process 

uranium and thorium ore by the Uranium Division of Mallinckrodt Chemical Works.

There were four periods for the WSP site:

1. Site acquisition and development, 1954–1957

2. Operational, 1957–1966

3. The U.S. Department of Energy (DOE) did not control WSP during the period 1967–

1985 and WSRP and WSQ during the period 1967–1974. The U.S. Department of 

Defense (DoD) had control of those Weldon Spring facilities during these periods.

4. Remediation, 1985–2002

WSP employment is covered under EEOICPA only during the operational (1957–1966) and 

remediation (1985–2002) periods when the AEC, U.S. Energy Research and Development 

Administration, and DOE had contractors and radioactive materials at WSP. 

WSQ and WSRP employment is covered during the operational period (1957–1966), the period 

1975–1984, and the remediation period (1985–2002).

2.2 Source terms

The radionuclides of concern are those that make up 95 percent of the potential internal dose. 

According to the TBD for internal dose, ORAUT-TKBS-0028-5, revision 04 (ORAUT, 2017c; 

also “TBD-5, revision 04”), the radionuclides of concern at the WSP site for DR are the naturally 

occurring isotopes of uranium (U-234, U-235, and U-238), their decay products (primarily 

thorium (Th)-230 and radium (Ra)-226), isotopes of natural thorium (Th-228 and Th-232) and 

their decay products, and recycled uranium (RU).

2.2.1 Uranium

ORAUT-TKBS-0028-5 (ORAUT, 2017c) recommends that for the purposes of DR, the 

assumption be made that all uranium processed at the WSP site was natural uranium from 1957 

through 1962, with a specific activity of 683 picocuries per milligram (pCi/mg). After 1962, all 

uranium is assumed to be enriched to 1 percent, with a specific activity of 973 pCi/mg.
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2.2.2 Radon

The three radon isotopes that are generated during the decay of U-235, U-238, and Th-232 are

Radon (Rn)-219, Rn-222, and Rn-220, respectively. Due to the limited amount of enriched 

uranium (EU), which contains U-235, processed at the WSP site, there was no large source of 

Ra-223 and, in turn, Rn-219. The risks associated with Rn-219 were insignificant due to its 

extremely short half-life (4 seconds) and small source term. Therefore, TBD-5, revision 04

(ORAUT, 2017c), considers only the inhalation intakes for Rn-222 and Rn-220 to be potentially 

significant.

2.2.3 Natural thorium

The conservative (favorable to claimant) assumption for natural thorium (Th-232) is that the 

decay products have built up to equilibrium. Thorium in the workplace at the WSP site was 

monitored by air concentration (section 5.2.3 of TBD-5, revision 04 (ORAUT, 2017c)). Thoron 

from Th-232 was present and a portion was released during the processing and storage of 

thorium at WSP and the associated waste storage locations. The thoron, with its subsequent 

progeny, would act as a potential source of internal exposure in the thorium process buildings 

and at waste storage locations. Although not measured directly, thoron exposures were 

determined and controlled by measuring thorium concentrations.

2.2.4 Recycled uranium

It should be assumed that all of the uranium that the WSP site processed beginning in 1961 was

RU. For the periods that include RU (i.e., after 1960), RU contaminant mass concentrations are 

provided in section 5.6.1.3.3 of TBD-5, revision 04 (ORAUT, 2017c). 

2.3 Internal monitoring 

The following summarizes the internal intake monitoring at the WSP site. SC&A obtained this 

information from ORAUT-TKBS-0028-4, revision 04 (ORAUT, 2020; also “TBD-4, 

revision 04”), and ORAUT-TKBS-0028-5, revision 04 (ORAUT, 2017c).

2.3.1 Operational period, 1957–1966

Urine bioassay was the primary method of determining uranium intakes during the production 

phase. There has been no indication so far that a routine urine sampling program was 

implemented for thorium. No urine bioassay data for thorium have been found in the worker 

files. Air monitoring results were used to derive potential WSP workers intakes (TBD-5, 

revision 04, section 5.5), and environmental intakes (TBD-4, revision 04, section 4.2.3) of 

various radionuclides, including thorium and radon, for which energy employees were not 

directly monitored.

2.3.2 DoD period, 1967–1985

There did not appear to be DOE contractor personnel present at the WSP during the DoD period,

and no bioassay monitoring records have been located for this period.

The WSQ and WSRP were under DoD control during the period 1967–1974 and under DOE 

control during the period 1975–1985. However, there did not appear to be DOE contractor 
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personnel present at the WSQ or the WSRP during the DOE control period 1975–1985 period, 

and no bioassay monitoring records have been located for this period. 

2.3.3 Remediation period, 1985–2002

An extensive bioassay monitoring program was conducted from 1991 to 2001 to detect intakes 

greater than 100 millirem committed effective dose equivalent.

2.4 External and ambient monitoring

The following summarizes external monitoring methods at the WSP site. SC&A obtained this 

information from TBD-4, revision 04 (ORAUT, 2020), and ORAUT-TKBS-0028-6, revision 01 

(ORAUT, 2013c).

2.4.1 Operational period, 1957–1966

Employees who worked in radiological areas were monitored, and their exposures should be 

accounted for in their dosimetry results. Documents obtained to date do not contain monitoring 

data that describe the ambient exposure rate at the WSP site during the operational period. 

2.4.2 DoD period, 1967–1985 

There did not appear to be DOE contractor personnel present during the DoD period, and no 

external monitoring records have been located for this period. There are no records of site 

surveys being conducted until 1982, except for a 1975 aerial radiological survey. 

2.4.3 Remediation period, 1985–2002

Personnel external monitoring was provided as needed during the remediation period. Site 

external ambient exposure monitoring began in 1982. 
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3 Subtask 1: Identify the Circumstances that Necessitated 

DCAS-PER-083

3.1 Chronology of events that necessitated PER-083

3.1.1 RU beginning in 1961

The revisions in TBD-4, revision 03 (ORAUT, 2017a), and TBD-5, revision 04 (ORAUT, 

2017c), consisted of recommending that the dose reconstructor use RU intakes beginning in 

1961. This corrected some language in the previous TBDs where it was stated that RU intakes be 

assessed after 1961.

3.1.2 RU contaminant radionuclides

The revisions in TBD-4, revision 02 (ORAUT, 2017b), consisted of recommending that the dose 

reconstructor use RU contaminate intakes as provided in table 4-1 (page 19), which was an 

expanded list of radionuclides compared to the previous guidance.

The revisions in TBD-5, revision 03 (ORAUT, 2017d), recommended that the dose reconstructor 

use RU contaminate intakes as provided in table 5-23 and table 5-24 (page 46), which consisted 

of an expanded list of radionuclides compared to the previous guidance.

3.1.3 Uranium specific activity

The revisions in TBD-4, revision 02 (ORAUT, 2017b), consisted of recommending that the dose 

reconstructor use an enriched uranium specific activity of 973 pCi/mg after 1962 (page 19). 

The revisions in TBD-5, revision 03 (ORAUT, 2017d), consisted of recommending that the dose 

reconstructor use an enriched uranium specific activity of 0.973 picocurie per microgram 

(pCi/μg) after 1962 (pages 15 and 47) instead of 0.783 pCi/μg as previously recommended

(ORAUT, 2013b, p. 13).

3.1.4 DCAS-PER-083

On January 7, 2019, NIOSH issued DCAS-PER-083 (NIOSH, 2019) for the WSP site, which 

addressed changes in DR procedures using the latest revisions (as of 2019) of the Weldon Spring 

TBDs: ORAUT-TKBS-0028-4, revision 03 (ORAUT, 2017a), and ORAUT-TKBS-0028-5, 

revision 04 (ORAUT, 2017c).

3.2 SC&A’s comments

SC&A reviewed the sequence of revisions of the Weldon Spring TBDs and PER-083. SC&A 

found that PER-083 addressed the pertinent changes in TBD-4 and TBD-5 that could potentially 

result in increases in internal or external doses.

SC&A reviewed the changes in TBD-4, revision 03 (ORAUT, 2017a), and revision 02 (ORAUT, 

2017b) compared to revision 01 (ORAUT, 2013a). SC&A also reviewed the changes in TBD-5, 

revision 04 (ORAUT, 2017c), and revision 03 (ORAUT, 2017d) compared to revision 02 

(ORAUT, 2013b).

The following is a summary of the changes that have the potential to increase assigned dose.
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3.2.1 ORAUT-TKBS-0028-4: Occupational environmental dose

Revision 03 of ORAUT-TKBS-0028-4 (ORAUT, 2017a) included the following changes that 

may increase assigned occupational environmental dose:

• RU beginning in 1961: Section 4.2.2.1 of revision 03 stated that the DR should assume, 

as favorable to claimants, that all of the uranium WSP processed beginning in 1961 was 

RU (ORAUT, 2017a, p. 11). Revision 02 of TKBS-0028-4, section 4.2.2.1, had stated

that the DR should assume as favorable to claimants that all of the uranium WSP 

processed after 1961 was RU (ORAUT, 2017b, p. 11).

• RU contaminants: Section 4.2.4 of revision 03 contained table 4-1, “RU contaminant 

intakes per unit activity of uranium, Bq/Bq U” (ORAUT, 2017a, p. 19), which provided

an expanded list of RU contaminants compared to section 4.2.2.1 of revision 01 

(ORAUT, 2013a, p. 11), which only included plutonium (Pu)-239, neptunium (Np)-237, 

and technetium (Tc)-99.

• Specific activity of enriched uranium: Section 4.2.4 of revision 03 stated that after 

1962, all uranium was assumed to be enriched to 1 percent, with a specific activity of 

973 pCi/mg (ORAUT, 2017a, p. 19), whereas revision 01 (ORAUT, 2013a) did not 

contain a section on radionuclide intake derivation.

SC&A did not identify any findings or observations in this review of revision 03 of TBD-4 

(ORAUT, 2017a).

3.2.2 ORAUT-TKBS-0028-5: Occupational internal dose

Revision 04 of ORAUT-TKBS-0028-5 (ORAUT, 2017c) includes the following changes that 

may increase assigned occupational internal dose:

• RU beginning in 1961: NIOSH states in section 5.2.4 of revision 04 that the DR should 

assume that all of the uranium processed at WSP beginning in 1961 was RU and that this 

is favorable to claimants (ORAUT, 2017c, p. 18). NIOSH stated in revision 03, 

section 5.2.4, that the DR should assume that all of the uranium processed at WSP after

1961 was RU and that this is favorable to claimants (ORAUT, 2017d, p. 18).

• RU contaminants: Section 5.6.1.3.3 of revision 04 contains table 5-23, “RU contaminant 

intakes per unit activity of uranium, Bq/g U,” and table 5-24, “RU contaminant intakes 

per unit activity of uranium, Bq/Bq U” (ORAUT, 2017c, pp. 45–46), which provide an 

expanded list of RU contaminants compared to section 5.2.4 of revision 02 (ORAUT, 

2013b, p. 16) that only included Pu-239, Np-237, and Tc-99.

• Specific activity of enriched uranium: Section 5.2.1 of revision 04 states that it is 

reasonable to assume that the EU at Weldon Spring was 1 percent enriched with a 

specific activity of 0.973 pCi/μg after 1962 (ORAUT, 2017c, pp. 15 and 47), whereas 

revision 02, section 5.2.1 (ORAUT, 2013b, p. 13), stated that it is reasonable to assume 

that the slightly enriched uranium processed at Weldon Spring was 1 percent enriched 

with a specific activity of 0.783 pCi/μg.
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SC&A did not identify any findings or observations in their review of revision 04 of TBD-5 

(ORAUT, 2017c).
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4 Subtask 2: Assess NIOSH’s Specific Methods for Corrective Action

NIOSH released revision 00 of TBD-4 in June 2005 (ORAUT, 2005a), revision 01 in May 2013

(ORAUT, 2013a), revision 02 in March 2017 (ORAUT, 2017b), and revision 03 in September 

2017 (ORAUT, 2017a). NIOSH released revision 00 of TBD-5 in June 2005 (ORAUT, 2005b), 

revision 01 in March 2013 (ORAUT, 2013d), revision 02 in May 2013 (ORAUT, 2013b), 

revision 03 in March 2017 (ORAUT, 2017d), and revision 04 in August 2017 (ORAUT, 2017c).

SC&A had previously reviewed revision 00 of TBD-4 and TBD-5 in 2009 (SC&A, 2009). 

Additionally, SC&A reviewed revision 01 of TBD-4 and revisions 01 and 02 of TBD-5 in 

subtask 2 of our review of DCAS-PER-051 (SC&A, 2023). However, revision 02 and 

revision 03 of TBD-4 and revisions 03 and 04 of TBD-5 had not been reviewed by SC&A. 

Therefore, subtask 2 of PER-083 included a review of the scientific basis and/or sources of 

information to ensure the credibility of the corrective action and its consistency with 

current/consensus science as described in the following section.

The 2017 revisions to TBD-4 and TBD-5 included several changes that could cause an increase 

in calculated doses, as described in section 3 of this report. NIOSH’s corrective actions in PER083 are described in section 3.0 of PER-083 and section 5 of this report.

4.1 Overview of SC&A’s review of Weldon Spring site profile 

For PER-083, SC&A reviewed TBD-4, revisions 02 and 03 (ORAUT, 2017b, 2017a), to 

determine if it contained technically correct methodology and information and referred to 

appropriate references as needed. SC&A analyzed changes that could decrease or increase 

assigned dose; we had no findings or observations concerning TBD-4. Additionally, SC&A 

reviewed TBD-5, revisions 03 and 04 (ORAUT, 2017d, 2017c), to determine if it contained 

technically correct methodology and information and referred to appropriate references as 

needed. SC&A analyzed changes that could decrease or increase assigned dose; we had no 

findings or observations concerning TBD-5. SC&A summarized the changes that have the 

potential to increase assigned dose in sections 3.2.1 and 3.2.2 of this report for TBD-4 and 

TBD-5, respectively, and had no findings or observations concerning the TBDs or PER-083.

4.2 SC&A’s comments 

SC&A confirmed that the revisions incorporated into Weldon Spring TBD-4, revisions 02 and 

03, and TBD-5, revisions 03 and 04, were scientifically sound. Since NIOSH reevaluated all 

applicable Weldon Spring claims and reworked the appropriate claims using the revised TBDs, 

SC&A finds NIOSH’s corrective actions to be appropriate. 

SC&A has no findings associated with subtask 2.
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5 Subtask 3: Evaluate the PER’s Stated Approach for Identifying the 

Number of DRs Requiring Reevaluation of Dose

5.1 NIOSH’s selection criteria

• RU beginning in 1961: According to section 3.0 of PER-083, NIOSH reviewed all 

Weldon Spring Plant claims completed between March 2017 and September 2017 and 

found that only one had employment in 1961. NIOSH reviewed the claim and found that 

recycled uranium intakes were assigned in 1961. Therefore, no further consideration for 

this issue was necessary.

• RU contaminants and specific activity of enriched uranium: According to section 3.0

of PER-083, NIOSH reevaluated all Weldon Spring claims and reworked the applicable 

claims using the latest version of the TBDs as of 2019: ORAUT-TKBS-0028-4, 

revision 03 (ORAUT, 2017a), and ORAUT-TKBS-0028-5, revision 04 (ORAUT, 2017c).

NIOSH searched for and evaluated all claims with employment at any one of the three Weldon 

Spring facilities in the NIOSH claims tracking system (NOCTS). Additionally, a keyword search 

was conducted on DR reports for the word “Weldon.” These searches resulted in 330 unique 

claims being identified. The following is a summary of the results of NIOSH’s search.

• Three claims were identified as being completed with the current TBD.

• 126 claims were identified as having a POC greater than 50 percent.

• 51 claims had been pulled from DR (primarily due to inclusion in the Mallinckrodt 

Special Exposure Cohort (SEC)).

• Seven claims were active at NIOSH at the time of the search and would be completed 

using the current TBDs.

• Two claims were determined not to have employment at Weldon Spring. They had been 

identified because the DR report mentioned Weldon Spring but actually had no 

employment there, and the Weldon Spring TBD was not used to estimate the dose.

• One claim met the criteria for the Mallinckrodt SEC and the DR was done prior to the 

designation of that SEC class. Therefore, it was removed from evaluation under PER083.

The remaining 140 claims were to be reevaluated under this PER as follows:

• Two of the claims were returned to NIOSH for a new DR (for other reasons) before the 

evaluation occurred. A new DR for these two claims would be completed using the 

current revisions of the TBD. Therefore, the two claims were removed from further 

consideration under PER-083. 

• 138 claims were evaluated using the current revisions of the TBD and all other applicable 

procedures, with results as follows:

o 129 claims had POC values that remained below 45 percent.
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o Four claims resulted in a POC between 45 percent and 52 percent. For those 

claims, the Interactive RadioEpidemiological Program (IREP) was run 30 times at 

10,000 iterations per NIOSH procedures. The resulting POC was less than 

50 percent for all four claims. 

o Five claims resulted in a POC greater than 50 percent. 

NIOSH will provide the U.S. Department of Labor (DOL) with the list of all the claims 

evaluated under this PER. Further, NIOSH will request that DOL return the five claims that 

would now result in a POC greater than 50 percent. 

5.2 SC&A’s comments

The selection criteria used by NIOSH for previously completed DRs that required reevaluation 

under PER-083 are valid. SC&A had no findings or observations associated with subtask 3. 
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6 Subtask 4: Conduct Audits of a Sample Set of Reevaluated DRs 

Mandated by DCAS-PER-083

Previous sections of this report describe changes introduced in revisions of WSP TBDs that

could increase the dose assigned for the periods covered for the WSP site. 

For SC&A to satisfy its commitment under subtask 4, SC&A suggests that two or three DR

claims be selected for a focused review from the WSP site during the covered period. SC&A

suggest that the claims selected should attempt to include the following criteria to address some 

of the major changes in the TBDs:

1. Environmental intakes consisting of exposure to EU (1963–1966) and RU (1961–2001)

contaminates

2. Internal intakes consisting of exposure to EU (1963–1966) and RU contaminates (1961–

2002)
Effective date: 9/22/2023 Revision No. 1 (Draft) Document No.: SCA-TR-2023-PER083 Page 16 of 17

NOTICE: This report has been reviewed to identify and redact any information that is protected by the

Privacy Act 5 U.S.C. § 552a and has been cleared for distribution. 

7 References

National Institute for Occupational Safety and Health. (2019). Weldon Sprint Plant TBD revision 

(DCAS-PER-083). https://www.cdc.gov/niosh/ocas/pdfs/pers/dc-per83-508.pdf

Oak Ridge Associated Universities Team. (2005a). Weldon Spring Plant – Occupational 

environmental dose (ORAUT-TKBS-0028-4, rev. 00). 

https://www.cdc.gov/niosh/ocas/pdfs/arch/weldon4.pdf 

Oak Ridge Associated Universities Team. (2005b). Weldon Spring Plant – Occupational internal 

dose (ORAUT-TKBS-0028-5, rev. 00). https://www.cdc.gov/niosh/ocas/pdfs/arch/weldon5.pdf 

Oak Ridge Associated Universities Team. (2013a). Weldon Spring Plant – Occupational 

environmental dose (ORAUT-TKBS-0028-4, rev. 01). 

https://www.cdc.gov/niosh/ocas/pdfs/arch/weldon4-r1.pdf

Oak Ridge Associated Universities Team. (2013b). Weldon Spring Plant – Occupational internal 

dose (ORAUT-TKBS-0028-5, rev. 02). https://www.cdc.gov/niosh/ocas/pdfs/arch/weldon5-

r2.pdf

Oak Ridge Associated Universities Team. (2013c). Weldon Spring Plant – Occupational 

external dosimetry (ORAUT-TKBS-0028-6, rev. 01). 

https://www.cdc.gov/niosh/ocas/pdfs/tbd/weldon6-r1.pdf

Oak Ridge Associated Universities Team. (2013d). Weldon Spring Plant – Occupational internal 

dose (ORAUT-TKBS-0028-5, rev. 01). https://www.cdc.gov/niosh/ocas/pdfs/arch/weldon5-

r1.pdf

Oak Ridge Associated Universities Team. (2017a). Weldon Spring Plant – Occupational 

environmental dose (ORAUT-TKBS-0028-4, rev. 03).

https://www.cdc.gov/niosh/ocas/pdfs/arch/weldon4-r3.pdf

Oak Ridge Associated Universities Team. (2017b). Weldon Spring Plant – Occupational 

environmental dose (ORAUT-TKBS-0028-4, rev. 02). 

https://www.cdc.gov/niosh/ocas/pdfs/arch/weldon4-r2.pdf

Oak Ridge Associated Universities Team. (2017c). Weldon Spring Plant – Occupational internal 

dose (ORAUT-TKBS-0028-5, rev. 04). https://www.cdc.gov/niosh/ocas/pdfs/tbd/weldon5-r4.pdf

Oak Ridge Associated Universities Team. (2017d). Weldon Spring Plant – Occupational internal 

dose (ORAUT-TKBS-0028-5, rev. 03). https://www.cdc.gov/niosh/ocas/pdfs/arch/weldon5-

r3.pdf

Oak Ridge Associated Universities Team. (2020). Weldon Spring Plant – Occupational 

environmental dose (ORAUT-TKBS-0028-4, rev. 04). 

https://www.cdc.gov/niosh/ocas/pdfs/tbd/weldon4-r4-508.pdf
Effective date: 9/22/2023 Revision No. 1 (Draft) Document No.: SCA-TR-2023-PER083 Page 17 of 17

NOTICE: This report has been reviewed to identify and redact any information that is protected by the

Privacy Act 5 U.S.C. § 552a and has been cleared for distribution. 

SC&A, Inc. (2009). Review of the NIOSH site profile for the Weldon Spring Site in Weldon 

Spring, Missouri (SCA-TR-TASK1-0028, rev. 0). 

https://www.cdc.gov/niosh/ocas/pdfs/abrwh/scarpts/sca-weldonsp-r0.pdf

SC&A, Inc. (2023). A review of NIOSH’s program evaluation report DCAS-PER-051, “Weldon 

Spring Plant” (SCA-TR-2023-PER051, rev. 1).