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Clarksville Modification Center

(Site Profile/Docket Number 096)

Location: Clarksville, Tennessee

Also Known As: Clarksville Facility, Fort Campbell, Mason & Hanger – Clarksville Base

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

To date, there are no open/active SEC petitions from Clarksville Modification Center.

Class(es) Added to the SEC

  • All employees of the Department of Energy, its predecessor agencies, and their contractors and subcontractors who worked at the Clarksville Modification Center, Ft. Campbell, in Clarksville, Tennessee, from August 1, 1949, through December 31, 1967, for a number of work days aggregating at least 250 work days, occurring either solely under this employment, or in combination with work days within the parameters established for one or more other classes of employees included in the Special Exposure Cohort.

    Note: This class was established from Petition 202

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.

Petition 202 (Jan 1, 1949 to Dec 31, 1967)

Petition 202
Steps in Petition Process: Petition Details:
Date Received


May 24, 2012


Date Qualified for Evaluation


May 31, 2012


Summary of Information in Petition


Job Titles and/or Job Duties: Workers potentially exposed to radioactive materials while working at the Clarksville Facility

Period of Employment: January 1, 1949 to December 31, 1967

Note: The information above is what qualified for evaluation. During our evaluation of whether dose reconstructions can adequately be completed for the above job titles and period of employment, information may cause NIOSH to change some the dates or job titles/duties. Therefore, as this petition proceeds through the SEC petition process and if an SEC class is proposed, the proposed class may not exactly match the above information.

Copy of the Petition Received


Clarksville Facility Petition [305 KB (2 pages)]


Federal Register Notice Announcing that a Clarksville Modification Center SEC Petition has met the Minimum Qualifications for Review and Evaluation


June 12, 2012 [80 KB (1 page)]


SEC Petition Evaluation Report


June 1, 2012 [420 KB (36 pages)]
Revised May 31, 2012


Evaluation Report Sent to the Advisory Board


June 4, 2012


Petition Discussed by the Advisory Board


The petition was discussed by the Advisory Board on June 20, 2012, during its regular meeting.

Note: the agenda for this meeting is available on the Advisory Board and Public Meetings page.

Advisory Board Recommendation on SEC Petition


July 27, 2012 [299 KB (2 pages)]
HHS Letters to Congress Regarding the SEC Petition


August 23, 2012 [700 KB (11 pages)]
HHS Designation of Additional Members to the SEC Designation
Federal Register Notice: Designation/Determination Regarding a Class of Employees for Addition to the Special Exposure Cohort



Note: A “designation” will be published if there is a recommendation to add a class to the SEC. A “determination” will be published if there is a recommendation not to add a class to the SEC.

Effective Date for the SEC Class


September 22, 2012


Federal Register Notice: Final Effect of Designation of a Class of Employees for Addition to the Special Exposure Cohort


October 3, 2012 [81 KB (1 page)]


Letter to DOL Regarding the Addition of a New Class of Employees to the SEC


September 28, 2012 [40 KB (1 page)]

Note: this only applies if the class is added to the SEC.

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

Advisory Board and NIOSH Discussions on Clarksville Modification Center

The Clarksville Modification Center 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 have 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.

  • OCAS-PER-027 Rev-00: Program Evaluation Report: Clarksville and Medina Site Profile – ORAU TBKS-0039 [15 KB (1 page)]
    October 30, 2007

    About this Document: New document to determine which previously completed claims require evaluation for the effect of issuing a revision to the Clarksville TBD.

    Summary: Prior to November 4, 2006, there were 65 Clarksville and Medina claims completed which had a probability of causation below 50%. NIOSH will review these dose reconstructions to determine if the dose assigned in consistent or higher than the issued TBD. NIOSH will provide DOL with the list of 65 claims as well as a determination on each claim as to whether a new Dose Estimate is required. Documentation for each claim not requiring a new dose reconstruction will provide the basis for that determination.

Public Comments on Clarksville Modification Center Documents

How to Submit Comments

Comments on Clarksville Modification Center Documents can be submitted to the NIOSH Docket Officer electronically by email at 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 (096) on all comments.

Comments Received

At this time, no comments have been submitted.

Document Archive for Clarksville Modification Center