Medina Modification Center

Special Exposure Cohort 

Petition Evaluation Report

Stuart L. Hinnefeld

Director

National Institute for Occupational Safety and Health

Division of Compensation Analysis and Support

June 2012

Santa Fe, NM
Petition Overview

 NIOSH determined it was not feasible to 

complete the dose reconstruction for an existing 

Medina claim

 May 24, 2012: Claimant was notified and 

provided with a copy of Special Exposure Cohort 

Petition Form A

 May 30, 2012: Petition (83.14) submitted to 

NIOSH

 May 31, 2012: NIOSH Evaluation Report issued 
Background

 EEOICPA covered from 1958-1966 (DOE)

 Located in San Antonio, TX, SW of Lackland AFB

 About 3,200 acres in size

 Constructed by AEC as a nuclear weapons 

storage and maintenance area

 Operated by AEC, Air Force, Sandia Corp., and 

contractor Mason and Hanger

 Sister facility to Clarksville Modification Center
Operations

 Storage operations began in 1955

 Nuclear capsule storage in underground vault 

structures (A Structures)

 Weapons assembly, modification, and 

disassembly in various structures

 AEC transferred operations to Pantex in 1965

 Decommissioning not complete until 1966 

 Workforce—ranged from ~95 workers in 1959 to 

a maximum of 669 in 1963
Sources of Available Information

 ORAU Team Site Profiles and Technical 

Information Bulletins (TIBs) and Procedures

 NIOSH Site Research Database

 Existing claimant files

 Information from Pantex Plant SEC evaluation

 Data captures
Data Capture Efforts

 DOE Opennet (OSTI data base)

 Standard data base search (DDRS, NNSA, CEDR, etc.)

 Internet search

 Nuclear Regulatory Commission (ADAMS)

 Hanford/PNNL

 DOE Legacy Management

 State of Texas

 Various DOE locations, especially Pantex

 Libraries 
NOSH/OCAS Claims Tracking System 

(information as of May 21, 2012)

 Medina claims submitted to NIOSH 46

 Claims that meet the recommended class years 46

 Dose reconstructions completed for claims 38

 that meet the class definition 

 Claims containing some internal dosimetry 0

 Claims containing some external dosimetry 16
Potential Radiation Exposures

 Internal

• Airborne uranium oxides (HEU and DU)

• Tritium gases 

• Radon

• Plutonium

 External

• Photon/beta and neutron exposures from

—Uranium

—Plutonium

—Ir-192 and Co-60 radiography sources
Personal Monitoring Data

 Internal monitoring data

• Indications are that baseline tritium analyses were 

performed; data has not been found by NIOSH

• No information on uranium or plutonium urinalysis

 External monitoring data

• Individual external and summary records for 

monitored workers from 1959-1966 available

• NTA film was added to badges in 1964, but 

discontinued shortly thereafter
Workplace and Source-Term Data

 Workplace data

• Routine air monitoring for tritium and alpha 

contamination was done 

• NIOSH has been unable to locate the data

 Source-term data

• Materials include uranium metals, uranium oxides, 

tritium, and plutonium

• Detailed source-term information is not available 

(some classification issues)
Feasibility of Dose Reconstructions

 Available internal monitoring records, process 

descriptions, and source-term data are 

inadequate to complete dose reconstructions 

with sufficient accuracy for the evaluated class 

of employees during the period from January 1, 

1958 through December 31, 1966

 The findings from this SEC evaluation are 

consistent with the SEC determinations for 

facilities with similar radiological exposures:

• Pantex Plant 

• Clarksville Modification Center, Ft. Campbell
Feasibility of Dose Reconstructions—cont. 

 External doses can be reconstructed using 

available external monitoring data and available 

dose reconstruction methods:

 Available film badge data likely from highest exposed 

worker group

 Neutron doses are assigned using neutron-to-photon 

ratios of similar operations

 Doses from X-ray examinations are assigned based on 

available methodology
Feasibility Summary

Feasibility Findings for Medina Modification Center

Source of Exposure

Dose 

Reconstruction 

Feasible

Dose Reconstruction 

NOT Feasible

Internal

X

External

 - Beta-Gamma X

 - Neutron X

 - Occupational 

Medical X-ray

X
Health Endangerment

 The evidence reviewed in this evaluation 

indicates that some workers in the class may 

have accumulated chronic radiation exposures 

through intakes of radionuclides and direct 

exposure to radioactive materials.

 Consequently, NIOSH is specifying that health 

may have been endangered for those workers 

covered by this evaluation who were employed 

for a number of work days aggregating at least 

250 work days within the parameters 

established for this class or in combination with 

work days within the parameters established for 

one or more other classes of employees in the 

SEC .
Proposed Class

All employees of the Department of Energy, its 

predecessor agencies, and DOE contractors or 

subcontractors who worked at the Medina 

Modification Center in San Antonio, Texas during the 

period from January 1, 1958 through December 31, 

1966, 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 in the Special Exposure Cohort.
Recommendation

 For the period from January 1, 1958 through 

December 31, 1966, NIOSH finds that radiation 

dose estimates cannot be reconstructed for 

compensation purposes

Class Feasibility Health Endangerment

January 1, 1958 –

December 31, 1966 No Yes