Department of Health and Human Services

Centers for Disease Control and Prevention

National Institute for Occupational Safety and Health

Evaluation Report for SEC-00245

Ames Laboratory 1971 - 1989

Thomas Tomes

Health Physicist

Division of Compensation Analysis and Support

Advisory Board on Radiation and Worker Health, 120th meeting

Albuquerque, NM

December 13, 2017
Department of Health and Human Services

Centers for Disease Control and Prevention

National Institute for Occupational Safety and Health

Ames Laboratory Site

 Ames Laboratory is Located on the campus of Iowa State 

University in Ames, Iowa

 An EEOICPA-covered facility from August 13, 1942 to 

present

 Various research in materials science and theory

 Developed methods and produced uranium and thorium 

metals metals during the 1940s and early 1950s
Department of Health and Human Services

Centers for Disease Control and Prevention

National Institute for Occupational Safety and Health

Background

 SC&A provided a review of the Ames Laboratory site 

profile to the Board in August 2013

 Among the Findings were comments that the site 

profile did not have a sufficient basis for estimating 

intakes for certain operations

 After additional data capture efforts and research 

NIOSH determined there is insufficient information 

to fully reconstruct internal dose prior to 1990
Department of Health and Human Services

Centers for Disease Control and Prevention

National Institute for Occupational Safety and Health

Background, cont.

 NIOSH initiated an 83.14 SEC petition for the 1971 

through 1989 period due to the inability to fully 

reconstruct internal doses

 NIOSH presumes available monitoring data and 

information in the site profile is sufficient for 

external dose reconstructions during the period
Department of Health and Human Services

Centers for Disease Control and Prevention

National Institute for Occupational Safety and Health

Previous SEC classes for Ames

Petition NIOSH recommended SEC class

SEC-00038 

All covered employees in five identified buildings from January 1, 1942 through 

December 31, 1954

- insufficient internal dose monitoring for thorium

- insufficient external dose monitoring (pre-1953)

SEC-00075

Various maintenance workers performing remediation and renovations in 

Wilhelm Hall from January 1, 1955 – December 31, 1970

- insufficient internal dose monitoring for thorium

SEC-00166 All covered employees from January 1, 1955 – December 31, 1960

- insufficient internal dose data for research work in Spedding Hall

SEC-00185 All covered employees from August 13, 1942 – December 31, 1970

- redefined previous classes to include all covered employees in all areas
Department of Health and Human Services

Centers for Disease Control and Prevention

National Institute for Occupational Safety and Health

NIOSH Proposed Class for SEC-00245

 All employees of the Department of Energy, its 

predecessor agencies, and their contractors and 

subcontractors who worked in any area at the Ames 

Laboratory in Ames, Iowa, during the period from 

January 1, 1971 through December 31, 1989

 Basis: insufficient monitoring data and information 

to reconstruct internal dose
Department of Health and Human Services

Centers for Disease Control and Prevention

National Institute for Occupational Safety and Health

Claims Affected by SEC-00245

 123 total claims for workers with employment in 

1971 through 1989

 16 claims have tritium bioassay data; some of those 

have a few bioassay data for other radionuclides

 21 claims have external dosimetry data
Department of Health and Human Services

Centers for Disease Control and Prevention

National Institute for Occupational Safety and Health

Ames Laboratory Operations

 Operations with potential radiation exposure:

• Research and Development with various 

radionuclides

• Ames Laboratory Research Reactor (1961 – 1982)

• Remediation
Department of Health and Human Services

Centers for Disease Control and Prevention

National Institute for Occupational Safety and Health

Research and Development

 Conducted 1942 to present

 Laboratory scale research with uranium, thorium, 

plutonium, rare earth elements, fission products, and 

various other radionuclides

 Used various equipment and devices to study 

materials and develop methods of production
Department of Health and Human Services

Centers for Disease Control and Prevention

National Institute for Occupational Safety and Health

Research and Development, cont.

 Performed developmental work to develop and test 

metals production methods on a larger than laboratory 

scale basis

 Produced batches of metal, including uranium and 

thorium, of up to 25 pounds

 Utilized laboratories for producing the pure metals

 Metals were cut and machined in a machine shop in the 

Metals Development Building
Department of Health and Human Services

Centers for Disease Control and Prevention

National Institute for Occupational Safety and Health

Ames Laboratory Research Reactor

 A 5 megawatt heavy water reactor located about one 

mile from the Iowa State main campus

 Operated from 1965 through 1977

 Decommissioning work was completed in 1981
Department of Health and Human Services

Centers for Disease Control and Prevention

National Institute for Occupational Safety and Health

Remediation Work

 Wilhelm Hall thorium decontamination projects in 

the 1970s and 1980s and beyond

 Miscellaneous remediation work in the 1980s:

• Gillman Hall stairwells

• Blockhouse demolished 

• Thorium-contaminated soils and debris excavated 

and shipped off-site
Department of Health and Human Services

Centers for Disease Control and Prevention

National Institute for Occupational Safety and Health

Radiological Monitoring Data

 Some environmental air samples from 1980-1982

 A few air samples from 1986 (6) and 1988 (3) are 

available from Wilhelm Hall and Spedding Hall

 A few air samples are available from the Alpha Operations 

Facility in the 1980s
Department of Health and Human Services

Centers for Disease Control and Prevention

National Institute for Occupational Safety and Health

Radiological Monitoring Data, cont.

 Loose contamination survey data in R&D facilities

• Significant amount of data starting in 1983

• Insufficient amount of data to characterize 

conditions during developmental work and 

decontamination work
Department of Health and Human Services

Centers for Disease Control and Prevention

National Institute for Occupational Safety and Health

Internal Dose Feasibility

 Ames Laboratory Research Reactor

• Tritium bioassay results are available for some 

claimants that can be used to estimate tritium 

dose

• Insufficient data to estimate intakes from other 

radionuclides
Department of Health and Human Services

Centers for Disease Control and Prevention

National Institute for Occupational Safety and Health

Internal Dose Feasibility, cont.

 Research and Development

• Various radionuclides were used including 

uranium, thorium, plutonium, fission products, 

rare earths, and other radionuclides

• Insufficient data to estimate intakes from the 

various radionuclides from Ames R&D work
Department of Health and Human Services

Centers for Disease Control and Prevention

National Institute for Occupational Safety and Health

Internal Dose Feasibility, cont.

 Remediation Work

• Primarily thorium and uranium contamination in 

various areas from the production era

• Insufficient monitoring data during remediation 

to estimate intakes with sufficient accuracy
Department of Health and Human Services

Centers for Disease Control and Prevention

National Institute for Occupational Safety and Health

Summary of SEC-00245

 There are insufficient monitoring data or source term 

and process information to reconstruct internal 

radiation doses from January 1, 1971 through 

December 31, 1989