Hangar 481

Special Exposure Cohort 

Petition Evaluation Report Update

Samuel E. Glover, PhD

Research Health Scientist

National Institute for Occupational Safety and Health

Division of Compensation Analysis and Support

August 2011

Richland, WA
Hangar 481 Site History

 Located at Kirtland Air Force Base in Albuquerque, 

New Mexico

 Ross Aviation, with operations based at Hangar 481 

during the covered period, was under contractual 

agreement with DOE

• Provided air transportation of personnel and equipment as 

using government owned aircraft at government owned 

facilities associated with DOE operations at the Sandia 

National Laboratory in Albuquerque, New Mexico

 Transported equipment—included packages 

containing radioactive materials associated with 

atomic weapons programs
Petition Overview

 February 27, 2009: 83.13 petition received

 September 8, 2009: Petition qualified for 

evaluation

 December 18, 2009: Evaluation Report issued

 February 2010: Evaluation Report presented at 

Advisory Board meeting

• Delay requested by petitioner until Freedom of 

Information Act (FOIA) material could be provided
Petition Overview—cont.

 July 2010: FOIA completed (DOE and NIOSH) 

 September 23, 2010: Revised Evaluation Report 

issued (updated photo of Hangar 481)

 November 2010: Evaluation Report re-presented 

at Advisory Board meeting

 January 2011: NIOSH and petitioners tour Hangar 

481 and provided a list of follow-up questions to 

Office of Secure Transport (OST) (DOE)

 June 2011: Responses provided by OST

 August 2011: Addendum to the Evaluation Report 

issued for Hangar 481
Summary of Petitioner Concerns 

1. Raw data lacking or unavailable

• Secondary summary data used for the evaluations

2. Contract existed back to 1970

• Covered period should be extended

3. Newly available documents had not been evaluated

4. Radioactive shipments were delivered to the Hangar 

481 building and stored

• The “hot pads” were used to load explosive materials

• Reliance on an interview with one former worker as the basis 

for determination that all radioactive shipments were handled 

at the “hot pads” was criticized
Summary of Petitioner Concerns—cont. 

5. Radioactive shipments were made using the AL-R8 

container

• In 1991, found to be inadequate to shield the contents 

(shielding for alpha and beta radiations was not disputed)

6. The Evaluation Report’s ambient external methods are 

not bounding

7. One individual states that barrels were stacked at the 

hangar which may have been nuclear waste and there is 

no apparent indication of “sweeps” that were done in 

the hangar building or adjacent areas

8. One pilot left his dosimeter in his locker and had an 

abnormally high dose reading when the badge was 

processed
NIOSH Follow-up Actions

 NIOSH and ORAU were able to work with Landauer

(the holder of Eberline’s data) to obtain the 

individual results rather than rely on summary data 

from REIRS from 1990-1994

• Data were compared to REIRS data and a complete match 

was obtained except for one year (1994)

• It was determined that an error had occurred in the REIRS 

database during data entry since the lifetime cumulative 

dose was entered rather than the annual dose

—This difference explained the one year which had a higher 

reported annual dose (1994)

• Program Manager for Occupational Exposure and Worker 

Health – Center for Epidemiologic Research (OEWH-CER) 

assisted in review of the data to help determine the cause 

of the discrepancy
NIOSH Follow-up Actions

 January 2011: NIOSH and petitioners tour Hangar 

481 and provided a list of follow-up questions to 

OST (DOE)

 March 2011: NIOSH received employee data from 

Landauer (who now owns Eberline, the dosimetry

provider to Hangar 481 during the covered period)

• NIOSH has also provided copies of the original dosimetry

to DOE

 June 2011 : Responses provided by OST

 August 2011: Addendum to Evaluation Report 

issued for Hangar 481
Update on Claim Data

(as of July 26, 2011)
NIOSH/Petitioner Questionnaire

 NIOSH and the petitioner were provided a detailed tour of 

the Hangar 481 facilities in January 2011

 NIOSH, with input from the petitioner, assembled a series of 

questions following the onsite tour and submitted these 

formally to OST

 Topics addressed in the questionnaire included:

 Facility information

 Radiological activities

 External dosimetry program

 Internal dosimetry program

 The following slides summarize the responses and findings 

regarding dose reconstruction at Hangar 481
Facility Location
Building Layout
Photos Inside Hangar 481

Interior of Hangar 481 Pilot Lockers in Hangar 481
OST Response: Facility Information

 Contracted activities began around 1970 and 

remained essentially unchanged

• DOL determines the covered period to be March 1, 1989 

through February 29, 1996

• Ross Aviation operations were actually relocated from a 

different facility to Hangar 481 in April 1984

 Separate “hot pads” are shown separate from 

Hangar 481
OST Response: Facility Information—cont . 

 Drawings provided show the Hangar facility, hot 

pads, personnel lockers, and location of where 

non-destructive testing was performed

 Starting in 1985 the facility was operated 24 

hours per day, 7 days per week, with 

approximately 200 employees

• Per the OST response, administrative personnel were 

only day shift with no overtime

 After 1987, operations were two shifts per day, 5 

days per week, with staffing levels reducing to 

about 80 employees in 1996
OST Response: Radiological Activities

 OST stated that no radiological activities were 

performed in Hangar 481

• Radiological packages were handled and loaded only at 

hot pads 2 and 5

• Unmonitored personnel were not allowed to come in 

contact with the packages

• Packages predominately tritium

 Non-destructive testing of planes was conducted 

once per year for a very short duration as previously 

discussed

• OST describes strict access controls and also that they 

were done at night
OST Response: External Dosimetry

 OST stated that Ross Aviation dosimetry program 

developed and managed by Eberline and Sandia

 No area dosimetry was performed at Hangar 481

 Neutron dosimetry was never provided at 

Hangar 481

 No X-rays for medical purposes were conducted 

at Hangar 481 facilities
OST Response: Internal Dosimetry

 OST stated that no bioassay program was ever 

implemented at Hangar 481

 No Ross facilities were monitored for contamination

• There was no need to perform surveys due to lack of 

use/storage of radioactive materials at the facility

 Surveys were performed off site (on the hot pads) 

where radioactive materials were handled

 OST indicated that no radiological accidents 

occurred at Hangar 481

 OST further indicated that thoriated welding rods 

were not used or present at Ross facilities
OST Response: General Questions

 The highest exposed were monitored for 

external dose (cabin security specialists and 

pilots) who actually handled the radiological 

materials

 No radioactive containers were ever delivered to 

the flight line adjacent to Hangar 481

 All Air Force and Sandia containers controlled by 

them until loaded at hot pads

• Any other delivery would have been a security 

violation
OST Response: General Questions—cont. 

 No radiation monitoring was performed inside 

Hangar 481 or the adjacent flight line

 The circumstances and locations related to the 

pilots’ lockers and radiographic activities (done 

only during off hours) provide the only available 

explanation for elevated personnel dosimeter 

readings as described by the petitioner
Internal Exposures

 On August 7, 1997, the Transportation Safety Division 

(TSD) of DOE’s Albuquerque Operations Office issued 

the Technical Basis for Radioactive Material Intake 

Potential regarding activities performed by Ross 

Aviation at Hangar 481

 Based on: 

1. The TSD special agents tasks (i.e., no contact with 

package contents)

2. The TSD’s operational history with confirmatory surveys 

(i.e., no package breach or leakage) 

3. The use of DOT compliant shipping packages and 

programs 

 The document concluded there is no credible path for an 

intake of radioactive materials during normal operations
Dosimetry Updated Results
Summary of External Dose Feasibility

 External dose records exist for many Ross Aviation 

personnel and have the REIRS reported data been 

verified using Eberline data from 1990-1994

 Data from the 1994 REIRS report was found to be 

incorrectly entered into the database (lifetime total 

instead of annual dose) and has been corrected in 

this addendum and DOE notified

 The individual results of these records or use of the 

highest dose received by monitored personnel 

adequately bounds unmonitored worker external 

dose
Summary of External Dose 

Feasibility–cont. 

 Data from 1996 was not included in REIRS (covered 

period ends February 29, 1996)

• NIOSH will use the highest annual dose for previous years 

for this 2-month period

 NIOSH will use the highest dose received in the 

entire year previously to bound any external dose 

for all employees

 The circumstances and locations related to the 

pilots’ lockers and radiographic activities (done only 

during off hours) provide the only available 

explanation for elevated personnel dosimeter 

readings as described by the petitioner
Summary of External Dose 

Feasibility–cont. 

 There is no credible potential for neutron exposures

 Potential doses from off-hour radiographic testing 

would be included in the reported personal 

monitoring data

 Ambient environmental external doses are included 

by using the existing personnel external monitoring 

data

 X-ray examinations are not included because 

medical X-rays were not performed on-site at 

Hangar 481
Summary of Internal Dose Feasibility

 No radioactivity was stored or handled at the 

Hangar 481 facility

 Radioactive materials handled by workers at 

Hangar 481 were in sealed DOT-compliant 

containers and monitored in accordance with 

DOT regulations to verify radiation and 

contamination levels on package exteriors

• Results of available radiological surveys performed on 

the packages and in the transport aircraft support this 

premise
Summary of Internal Dose 

Feasibility—cont. 

 Based on the available information on the 

radiological program and potential for internal 

exposure sources, NIOSH concludes that internal 

radiological exposures to Ross Aviation 

employees resulting from services rendered for 

the DOE at Hangar 481 are unlikely to have 

occurred

 Sandia National Laboratory, being an adjacent 

facility, was used to provide a bounding estimate 

of the dose from ambient environmental 

internal dose during the covered period
Feasibility Summary

Feasibility Findings for SEC-00139

Source of Exposure

Dose Reconstruction 

Feasible

Dose Reconstruction 

NOT Feasible

Internal

X

External

- Beta-Gamma X

- Neutron N/A

- Occupational 

Medical X-ray

N/A