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Weldon Spring Plant

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(Site Profile/Docket Number 53)

Location: Weldon Spring, Missouri

Also known as: Mallinckrodt, Weldon Spring Chemical Co., Weldon Spring Site Remedial Action Project (WSSRAP), WSS

Special Exposure Cohort Petition Information

The Special Exposure Cohort (SEC) is a unique category of employees established by the Act (42 CFR Part 83). Claims compensated under the SEC do not have to go through the dose reconstruction process. To qualify for compensation under the SEC, a covered employee must meet specific requirements (e.g., must have at least one of 22 “specified cancers,” and have worked for a specified time period at one of the SEC sites). Classes of employees and work sites can be considered for addition to the SEC through a NIOSH petition process. More information about the Special Exposure Cohort can be found on our Frequently Asked Questions page.

Open/Active SEC Petitions

There are currently no open/active petitions from Weldon Spring Plant.

Classes Not Added to the SEC

  • All employees of the Department of Energy, Department of Energy contractors, or subcontractors who worked in any area at the Weldon Spring Plant in Weldon Spring, Missouri, during the applicable covered operational period from January 1, 1957, through December 31, 1967

    Note: This class was established from Petition 143

Petitions Qualified for Evaluation

Below is a list of the petitions that qualified for evaluation. Select a petition on the list to view the table for that particular petition.

Worker Outreach Activities

Based on a recommendation from the Advisory Board to provide workers and site experts with opportunities to participate in developing the technical documents used in dose reconstruction, NIOSH established a Worker Outreach Program.

At Worker Outreach Meetings, current and former DOE and AWE employees have opportunities to obtain information about Site Profiles, Technical Basis Documents, and Technical Information Bulletins, and to provide information for consideration and possible use in dose reconstruction. This process is valuable to ensure that the technical documents used in dose reconstruction contain correct and useful information.

Below are the Worker Outreach Activities for the Weldon Spring Plant:

Advisory Board Work Group on Weldon Spring Plant

This Work Group is responsible for reviewing the Weldon Spring Plant Site Profile, the SEC petition from Weldon Spring Plant petitioners, the NIOSH Evaluation Report of the petition, the SC&A Review of the Weldon Spring Plant Site Profile, considering issues raised by the Board’s contractor (SC&A) concerning the Site Profile and the petition Evaluation Report, and for assisting NIOSH and SC&A in the resolution of such issues. The Work Group may recommend to the Board, changes in the Site Profile as appropriate. The Work Group should strive to develop a recommendation to the Board on whether a class should be added to the SEC.

Work Group Members:

  • Richard A. Lemen, Ph.D., M.S.P.H. (Chair)

  • Paul L. Ziemer, Ph.D.

Meeting Information:

Pre-Decisional Document Policy

Please note that as part of the procedures and processes of the Advisory Board’s Work Groups, several kinds of pre-decisional documents may be developed. These pre-decisional documents, such as white papers, matrices, working drafts, etc., are distributed among Work Group members as research and background tools to facilitate discussion and deliberation. Although discussion during a public meeting may cover pre-decisional documents, these documents often are not further revised or finalized, and thus do not reflect the final determination or evaluation of the Advisory Board and its Work Groups. Additionally, some pre-decisional documents not otherwise posted on the website may contain sensitive information, which would require an interested party to obtain such documents by filing a Freedom of Information Act (FOIA) request with the CDC/ATSDR FOIA office at foiarequests@cdc.gov.

Technical Documents

If the energy employee’s personal radiation information is incomplete, NIOSH will use other sources to estimate the radiation dose. This may involve using technical documents called Site Profiles, Technical Basis Documents, and Technical Information Bulletins.

Site Profile

  • Introduction [99 KB (9 pages)]
    Revised May 24, 2013

    Revision Includes: Revision implemented according to guidance from ORAUT-PROC-0031, Rev. 04. Section 1.1: Replaced introductory text with updated template language. Added Section 1.1.1, “Purpose,” and changed heading from “Site Profile Description” to “Scope” for Section 1.1.2. Minor technical editing conducted for Section 1.2. Deleted repetitious details and results that appear in subsequent sections of the Site Profile from Sections 1.3 through 1.6. Updated the Acronyms and Abbreviations and the References sections. No sections were deleted. No changes occurred as a result of formal internal review. Incorporates formal NIOSH review comments. Constitutes a total rewrite of the document.

  • Site Description [800 KB (44 pages)]
    Revised September 12, 2017

    Revision Includes: Corrects wording in Section 2.4.1 regarding the year recycled uranium work began at the Weldon Spring Plant. Includes editorial changes. Updates references in the text and in the Reference Section. No sections were deleted. No changes were needed as a result of formal internal review. Incorporates formal NIOSH review comments.

  • Occupational Medical Dose [152 KB (12 pages)]
    Revised January 30, 2013

    Revision Includes: Incorporates historical documents captured since the first revision, to include skin doses for all areas of skin, and to address SC&A comments. Incorporates formal internal and NIOSH review comments. Constitutes a total rewrite of the document.

  • Occupational Environmental Dose [3 KB (38 pages)]
    Revised March 27, 2020

    Revision Includes: Incorporates relevant information from ORAUT-PROC-0060 Rev. 01. Rewritten such that only a best-estimate approach is used in determining the environmental doses. Radon-220 and 228Ra intakes were added for years of thorium operations from 1963 to 1966. Table added (Table 4-1) for airborne concentrations, which feed the radionuclide intake tables (Tables 4-3 and 4-4). Intakes based on averages were converted to medians of a lognormal distribution using equations in Battelle-TIB-5000, resulting in an adjustment factor of 1.828. The following years, facilities, and nuclides were adjusted by dividing by 1.828 as they were not adjusted in Rev 03: WSRP U-234: 1990–2001; WSRP Radon: 1983–2001; WSP U-234: 1985–2001; WSP Th-230: 1985–2001; WSP Radon: 1985–2001; WSQ Radon: 1983–2001. WSQ U-234 values for the years 1990, 1991, 1993–1996, and 1998–2001 were changed. Rev 03 set these values equal to 0 as the airborne concentrations were considered to be insignificant. However, the nonzero airborne U-234 concentrations were included in this revision. The airborne concentration values for 1992 and 1997 were equal to zero thus they were not changed. The RU contaminant intakes from 1988 to 2001 were changed as the uranium intakes for those years were decreased by a factor of 1.828 from converting from an arithmetic mean or average to a median of a lognormal distribution. Intakes were converted to units of activity per calendar day by dividing by an average of 365.25 days per calendar year. Maximum intakes for U and Rn added to Table 4-1. Incorporates formal internal and NIOSH review comments. Constitutes a total rewrite of the document.

  • Occupational Internal Dose [776 KB (61 pages)]
    Revised August 31, 2017

    Revision Includes: Initiated in response to SC&A comments about correction of wording to make it clear that the start year for work with recycled uranium was 1961. Affected sections are: 5.2.4, and 5.2.4.1. Includes editorial changes. References updated as appropriate. No sections were deleted. Incorporates formal internal review and formal NIOSH review comments.

  • Occupational External Dose [3 MB (45 pages)]
    Revised February 6, 2013

    Revision Includes: Removes all surrogate data except the data from MCW. Adds new material located since the last revision. Includes a correction factor to account for worker-radiation source geometry to be applied to the measured and missed photon dose for operators, material handlers and trade workers to avoid an underestimate of dose. Organs most affected by this are those in the lower torso (stomach, pancreas, ovaries, etc.). DCAS-TIB-0013 was included as a reference and used to determine this geometric correction factor of 2.1. Incorporates responses and commitments based on SC&A and Advisory Board Working Group issues. Incorporates formal internal and NIOSH review comments. Constitutes a total rewrite of the document.

Advisory Board and NIOSH Comments and Discussion Papers on Weldon Spring Plant

The Weldon Spring Plant discussion papers listed below are working documents prepared by NIOSH or its contractor for use in discussions with the Advisory Board on Radiation and Worker Health or its Working Groups or Subcommittees. Draft, preliminary, interim, and white paper documents are not final NIOSH or Advisory Board (or their technical support and review contractors) positions unless specifically marked as such. These documents represent preliminary positions taken on technical issues prepared by NIOSH or its contractor.

The discussion papers have been reviewed to identify and redact any information that is protected by the Privacy Act 5 USC §552a and has been cleared for distribution.

Program Evaluation Plans (PEPs) and Program Evaluation Reports (PERs)

NIOSH is committed to applying the best available science in dose reconstructions. In keeping with this commitment, completed cases with probabilities of causation less than 50% are reviewed as relevant new information becomes available. The results of these reviews are described in a Program Evaluation Report (PER). The PER details the effect, if any, of the new information on the completed dose reconstruction. If it appears that the new information may result in an increase in dose for a completed dose reconstruction with a probability of causation of less than 50%, NIOSH is committed to working with the Department of Labor to reopen and rework the dose reconstruction, as appropriate. A Program Evaluation Plan (PEP) describes plans for evaluating specific program details or issues.

  • DCAS-PER-092, Rev. 0: Program Evaluation Report, Weldon Spring Plant [30 KB (3 pages)]
    March 29, 2021

    About this Document: Determines the effect of issuing revision 4 to ORAUT-TKBS-0028-4 (Weldon Spring Plant TBD, section 4) on previously completed claims.

    Summary: Revision 4 of the Environmental section of the TBD was issued on 3/27/2020. All other revisions to the Environmental section or other sections of the TBD were evaluated in a previous PER (DCAS-PER-083). Therefore, this PER will evaluate only the changes made in revision 4 of the Environmental section of the TBD.

  • DCAS-PER-083: Program Evaluation Report for Revision of the Weldon Spring Plant Site Profile (ORAUT-TKBS-0028-4 and ORAUT-TBKS-0028-5) [40 KB (3 pages)]
    January 7, 2019

    Revision Includes: New document to determine the effect of revising the Weldon Spring Plant Site Profile (ORAUT-TKBS-0028-4 and ORAUT-TBKS-0028-5) on previously completed claims.

    Summary: Doses for 138 affected claims were recalculated using the current revisions of the TBD, as well as all other applicable procedures. Five claims resulted in a POC greater than 50%. NIOSH will provide the Department of Labor with the list of all the claims evaluated under this PER. Further, NIOSH will request DOL return the 5 claims that would now result in a POC greater than 50%.

  • DCAS-PER-051, Rev. 0: Weldon Spring Plant Program [92 KB (2 pages)]
    March 4, 2015

    About this Document: Determines the effect of a revision to the Weldon Spring Plant Technical Basis Document (TBD) on previously completed claims.

    Summary: Dose for 112 claims was recalculated using the current revisions of the TBD as well as any other applicable documents. The resulting Probability of Causation (POC) for 101 of the claims was below 45%. Eight of the claims resulted in a POC greater than 50%. The remaining three claims had a POC between 45% and 50%. For those 3 claims, IREP was run 30 times at 10,000 iterations per NIOSH procedures and the resulting POC was still less than 50% for the each of those claims. NIOSH will provide the Department of Labor with the list of all the claims evaluated under this PER. Further, NIOSH will request that DOL return the 8 claims that would now result in a POC greater than 50%.

Public Comments on Weldon Spring Plant Documents

How to Submit Comments

Comments on Weldon Spring Plant documents can be submitted to the NIOSH Docket Officer electronically by email at nioshdocket@cdc.gov or printed comments can be mailed to:

NIOSH Docket Office
Robert A. Taft Laboratories, MS-C34
1090 Tusculum Avenue
Cincinnati, OH 45226
Please include the Site Profile/Docket Number (53) on all comments.

Comments Received

No public comments have been received on Weldon Spring Plant Documents at this time

Document Archive for Weldon Spring Plant

  • Section 1: Introduction section

    • Page Change Revision June 30, 2008 [89 KB (11 pages)]

      Revision Includes: Approves page change revision initiated to eliminate reference to a user’s guide on page 10 in Section 1.2, which was never published due to a change in policy. Addsan Attributions and Annotations Section on page 10, updated NIOSH required language on page 5 in Section 1.1, and ORAU team references on pages 8 and 11. Now uses term, “favorable to claimant” on pages 6, 9, and 10 in Sections 1.1 and 1.2. No sections were deleted. Incorporates formal internal review comments. No changes were needed as a result of NIOSH formal review.

    • Approved June 28, 2005 [82 KB (11 pages)]

  • Section 2: Site Description section

    • Approved March 24, 2017 [1.3 MB (45 pages)]

      Revision Includes: Revision initiated to refer to Rev 02 of the Fernald internal dose technical basis document regarding recycled uranium contaminants and their mass concentrations. Includes editorial changes. No changes occurred as a result of formal internal review. Incorporates formal NIOSH review comments. Constitutes a total rewrite of the document.

    • Approved May 21, 2013 [693 KB (44 pages)]

      Revision Includes: Incorporates data that has been found since the initial draft was issued. Updates description of processed materials and throughputs. No changes occurred as a result of formal internal review. Incorporates formal NIOSH review comments. Constitutes a total rewrite of the document.

    • Approved June 24, 2005 [1.2 MB (39 pages)]

  • Section 3: Occupational Medical Dose section

  • Section 4: Occupational Environmental Dose

    • Revised September 8, 2017 [707 KB (34 pages)]

      Revision Includes: Revision initiated to incorporate SC&A comments regarding the date stated for work containing recycled uranium (from 1961 and on). Changes were made in Section 4.2.2.1. Updated references in the text and in the Reference Section. Added and deleted some acronyms and abbreviations from the listing. No sections were deleted. No changes were needed as a result of formal internal review. Incorporates formal NIOSH review comments.

    • Revised March 29, 2017 [2.8 MB (34 pages)]

      Revision Includes: Refers to ORAUT-TKBS-0017-5, Feed Materials Production Center – Occupational Internal Dose, in relation to RU contaminants and their mass concentrations. Section 4.2.4 added which includes a table of ratios of RU contaminant intake activity per unit activity uranium, Bq/Bq U. Changes table for maximum annual median intakes to include the additional RU contaminants. Includes editorial changes. Incorporates formal internal and NIOSH review comments. Constitutes a total rewrite of the document.

    • Revised May 17, 2013 [707 KB (35 pages)]

      Revision Includes: Revises the TBD as a result of completion of Advisory Board Work Group issues. Includes information in Section 4.2.2.1 about the drying of the raffinate pits and its potential for resuspension of pit radionuclide content. Includes factors for calculation of recycled uranium contaminant activity based on ppb or pCi uranium. Revises and implements according to ORAUT-PROC-0031, Rev. 02. Adds a table for maximum sitewide median intake values to comply with PROC-0031, and also adds a table of annual median intake values for the WSCP, WSRP, and WSQ. Replaces introductory text with updated template language in Section 4.1. Revised Section 4.1.1, Purpose, and Section 4.1.2, Scope. Revises Sections 4.2.1 and 4.2.2 to more specifically target the radionuclides of concern and source terms that contribute to 95% of the potential internal dose. Revises the approach to determination of annual intake of radionuclides (Section 4.2.3.1) during the operational period to optimize the use of available site-specific monitoring data. Adds a table of annual median values for occupational external dose to be used as surrogates for onsite ambient dose during the operational period. Adds Section 4.4 as a summary of environmental doses for use by dose reconstructors and provides tabulated inhalation intakes and ambient dose default values. Incorporates formal internal and NIOSH review comments. Constitutes a total rewrite of the document.

    • Approved June 28, 2005 [517 KB (35 pages)]

  • Section 5: Occupational Internal Dose

    • Revised March 14, 2017 [793 KB (61 pages)]

      Revision Includes: Responds to revision of ORAUT-TKBS-0017-5, Feed Material Production Center – Occupational Internal Dose, in relation to recycled uranium contaminants. Updates discussion of recycled uranium in Section 5.2.4 in reference to the recycled uranium contaminant mass concentrations detailed in the Fernald internal dose TBD. Adds Section 5.6.1.3.3 for RU including tables in units of Bq RU contaminant per g U and in Bq/Bq U to assist the DR in calculating the RU contaminant activities. Changes the value for the specific activity for 1% enriched uranium from 0.783 pCi/μg to 0.973 pCi/μg to match that used in the revised Fernald internal dose Technical Basis Document (Rev 02). Includes editorial changes. Incorporates formal internal and NIOSH review comments. Constitutes a total rewrite of the document.

    • Revised May 21, 2013 [642 KB (60 pages)]

      Revision Includes: Modifies the indoor radon equilibrium factor from 0.5 to 0.7 to coincide with Advisory Board meeting transcripts from September 19, 2012. This increases the radon intake value from 8.8 WLM/year to 12.4 WLM/year. Changes were made in Section 5.6.1.3 and Table 5-23. No changes occurred as a result of formal internal and NIOSH review.

    • Revised March 15, 2013 [659 KB (60 pages)]

      Revision Includes: Incorporates numerous minor corrections and edits. SRDB numbers and page numbers were added. In Section 5.2.1, the specific activity for slightly enriched (1%) uranium was adjusted to agree with the formula in DOE 2001a. Sections 5.2.2 related to uranium decay products were edited to reflect the fact that the early uranium mills may not have been effective in removing thorium and to increase the amount of Th-230 and daughters to assume in calculations. The maximum concentrations for certain decay products at the WSRP and WSQ were eliminated. A discussion was added in Section 5.2.3 on potential intakes from thoron. Site-specific ratios of Th-230 to other contaminants were developed in Section 5.6.1.1 for use during initial uranium processing. DWA concentrations for thorium dust measurements were added as Attachment A, and these values were used to create a new table of thorium intakes in Section 5.6.1.2. Thoron guidance was also added to this section. A statement was added in Section 5.6.1.1 to use Friday urine sampling data statistics to avoid underestimating intakes. The estimated annual exposure from radon was increased in Section 5.6.1.3, and Section 5.2.4 on recycled uranium was updated in response to issues raised in the Advisory Board Work Group. Thorium-232 intake rates updated to reflect an 8-hour workday normalized to a calendar for each of the years for Th-232 operations, and equations were included in the text regarding calculation of the median and 95th percentiles of the Th-232 intake rates. Incorporates formal internal and NIOSH review comments. Constitutes a total rewrite of the document.

    • Approved June 28, 2005 [506 KB (43 pages)]

  • Section 6: Occupational External Dose section