Y-12

Special Exposure Cohort 

Petition Evaluation Report

LaVon B. Rutherford, CHP

Special Exposure Cohort Health Physics Team Leader

National Institute for Occupational Safety and Health

Division of Compensation Analysis and Support

August 2011

Richland, WA
Petition Overview

 NIOSH unable to complete the dose 

reconstruction for an existing Y-12 claim

 April 13, 2011: NIOSH notified the claimant and 

provided a copy of Special Exposure Cohort 

Petition Form A

 April 22, 2011: Petition (83.14) received 

 July 19, 2011: NIOSH Evaluation Report approved 
Proposed Class

All employees of the Department of Energy, its 

predecessor agencies, and DOE contractors or 

subcontractors who worked at the Y-12 facility in Oak 

Ridge, Tennessee during the period from January 1, 

1948 through December 31, 1957, 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.
Y-12 Operations (1948-1957)

 “Second Era” of operations at Y-12

 Uranium operations 

• Recycling/salvage 

• Machining and component assembly

 Lithium isotope separation 

• Li-6 from Li-7

 Thorium studies

• Co-precipitation medium for U recovery

• Isotopic Separation Program (calutrons)

• Research and development work involving thorium

• ORNL research and development support
Y-12 Operations (1948-1957)—cont.

 Waste disposal

• S-3 ponds: seepage pits

• New Hope Pond: retention basin

 ORNL work at Y-12: 

• Production of stable and radioactive isotopes for medical 

research using the Y-12 calutrons

• Plutonium isotopic separation – process design

• Operation of 86-inch cyclotron for isotope production and 

nuclear physics research 

• Critical Experiments Facility

• Van de Graff Accelerator (5 MeV)

 Weapons assembly/disassembly
Existing Y-12 SEC Classes 

 SEC-0018 (83.13) 

• 1943-1947

• Specified job titles (uranium enrichment workers)

 SEC-0098 (83.14)

• 1943-1947

• All workers 

 SEC-0028 (83.13)

• 1948-1957

• Specified areas (buildings and certain operations)

 SEC-00186 (83.14)

• 1948-1957

• All workers, all areas
SEC Class Definition Review

 November 2010: NIOSH assessment report to review SEC 

class definitions issued

 Systematic review of existing SEC class definitions based on a 

NIOSH evaluation and recommendation

 Review based on criteria of consistency, applicability, and 

whether any actions may be required by NIOSH to correct an 

existing class definition (such as possible problems with 

implementation by DOL) 

 Review specific to the criteria used in the SEC evaluation 

report to develop the class definition (e.g., feasibility time 

period, access controls, DOL implementation)
SEC Class Definition Review—cont.

 Report Findings

• Most of issues and discrepancies identified in the 

NIOSH report were associated with the evolution of 

the NIOSH process for defining a class in an SEC 

Evaluation Report 

—Early classes were closely related to the petitioner 

proposed class

—Early classes were established based on perceived 

limitations and sometimes without the review by DOL 

to ensure they could be implemented as written

• Over time, the need to expand and/or adjust the 

proposed SEC class to address DOL class 

implementation issues was recognized to ensure 

claimants were not inadvertently excluded
SEC Class Definition Review—cont. 

 SEC0028 class definition: 

Department of Energy (DOE) employees or DOE contractor or 

subcontractor employees who were monitored or should have 

been monitored for: thorium exposures while working in 

Building 9201-3, 9202, 9204-1, 9204-3, 9206, or 9212 at Y-12

for a number of work days aggregating at least 250 work days 

from January 1948 through December 1957, or in combination 

with work days within the parameters established for one or 

more classes of employees in the SEC; or radionuclide 

exposures associated with cyclotron operations in Building 

9201-2 at Y-12 for a number of work days aggregating at least 

250 work days from January 1948 through December 1957, or 

in combination with work days within the parameters 

established for one or more classes of employees in the SEC
SEC Class Definition Review—cont.

 The current SEC class is recommended to remove 

the restriction on the class definition of 

SEC-0028 using today’s criteria

• SEC-0028 class definition specifies job types and work 

location

• Available employment records do not generally 

indicate work location 

• Worker movements across the site undocumented
Feasibility of Dose Reconstruction

 Feasibility of Dose Reconstructions:

• NIOSH lacks sufficient monitoring, process, or source 

information for various Y-12 operations to estimate 

internal radiation doses to Y-12 employees for the 

period of January 1, 1948 through December 31, 

1957

• SEC-0028: infeasibility was driven by the inability to 

bound internal exposures from thorium operations 

and cyclotron operations

• NIOSH will use any internal and external individual 

personal monitoring data for partial dose 

reconstructions as appropriate
Feasibility Summary

Feasibility Findings for SEC-00186

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 .
Recommendation

 For the period January 1, 1948 – December 31, 1957, 

NIOSH finds that radiation dose estimates cannot be 

reconstructed for compensation purposes

Class Feasibility Health Endangerment

January 1, 1948 –

December 31, 1957 No Yes