Mortality among Tennessee Eastman Corporation (TEC) uranium processing workers, 1943–2019

Abstract

Background

There are few occupational studies of women exposed to ionizing radiation. During World War II, the Tennessee Eastman Corporation (TEC) operated an electromagnetic field separation facility of 1152 calutrons to obtain enriched uranium (²³⁵U) used for the Hiroshima atomic bomb. Thousands of women were involved in these operations.

Materials and methods

A new study was conducted of 13,951 women and 12,699 men employed at TEC between 1943 and 1947 for at least 90 days. Comprehensive dose reconstruction techniques were used to estimate lung doses from the inhalation of uranium dust based on airborne measurements. Vital status through 2018/2019 was obtained from the National Death Index, Social Security Death Index, Tennessee death records and online public record databases. Analyses included standardized mortality ratios (SMRs) and Cox proportional hazards models.

Results

Most workers were hourly (77.7%), white (95.6%), born before 1920 (58.3%), worked in dusty environments (57.0%), and had died (94.9%). Vital status was confirmed for 97.4% of the workers. Women were younger than men when first employed: mean ages 25.0 years and 33.0 years, respectively. The estimated mean absorbed dose to the lung was 32.7 mGy (max 1048 mGy) for women and 18.9 mGy (max 501 mGy) for men. The mean dose to thoracic lymph nodes (TLNs) was 127 mGy. Statistically significant SMRs were observed for lung cancer (SMR 1.25; 95% CI 1.19, 1.31; n = 1654), nonmalignant respiratory diseases (NMRDs) (1.23; 95% CI 1.19, 1.28; n = 2585), and cerebrovascular disease (CeVD) (1.13; 95% CI 1.08, 1.18; n = 1945). For lung cancer, the excess relative rate (ERR) at 100 mGy (95% CI) was 0.01 (–0.10, 0.12; n = 652) among women, and −0.15 (–0.38, 0.07; n = 1002) among men based on a preferred model for men with lung doses <300 mGy. NMRD and non-Hodgkin lymphoma were not associated with estimated absorbed dose to the lung or TLN.

Conclusions

There was little evidence that radiation increased the risk of lung cancer, suggesting that inhalation of uranium dust and the associated high-LET alpha particle exposure to lung tissue experienced over a few years is less effective in causing lung cancer than other types of exposures. There was no statistically significant difference in the lung cancer risk estimates between men and women. The elevation of certain causes of death such as CeVD is unexplained and will require additional scrutiny of workplace or lifestyle factors given that radiation is an unlikely contributor since only the lung and lymph nodes received appreciable dose.

Keywords:

• Radiation epidemiology
• uranium processing
• lung cancer
• Oak Ridge Calutron Workers
• Manhattan Project

Acknowledgements

We gratefully acknowledge the advice and discussions from Dr. Diane Cookfair for her insights into the conduct of her comprehensive case-control study of lung cancers among TEC male workers; Mr. Jack Beck for his insights into the dose reconstructions used in the Cookfair et al. (1983) studies; Dr. Lynn Sowder for discussions related to the complex algorithms used in the past to convert measurement of uranium dose into estimates of absorbed dose to lung; and Ms. Emily Sirko for extensive tracing support. The findings and conclusions in this paper are those of the authors. Its publication does not necessarily represent the official position of or imply endorsement by the National Council on Radiation Protection and Measurements, Oak Ridge National Laboratory, Oak Ridge Associated Universities, Memorial Sloan Kettering Cancer Center, Vanderbilt University, or any of the acknowledged agencies.

Disclosure statement

The authors report no conflicts of interest. The authors alone are responsible for the content and writing of the paper.

Additional information

Funding

The study of workers at the Tennessee Eastman Corporation (Y-12, 1943–1947), a component of the Million Person Study, was supported in part by grants from the U.S. Department of Energy (Grant No. DE-SC0008944 awarded to the National Council on Radiation Protection and Measurements, which included interagency support from the U.S. Nuclear Regulatory Commission, the U.S. Environmental Protection Agency, and the National Aeronautics and Space Administration; and more recent Grants No. DE-AU0000042 and DE-AU0000046); a grant from the U.S. Nuclear Regulatory Commission (NRC-HQ-60-14-G-0011); grants from the Centers for Disease Control and Prevention (5UE1EH000989, 5NUE1EH001315); and grants from the National Aeronautics and Space Administration (NNX15AU88G, 80NSSC17M0016). Contract support was received from the Naval Sea Systems Command (N00024-17-C-4322). Further, contract support was received by Oak Ridge National Laboratory from the Office of Radiation and Indoor Air, U.S. Environmental Protection Agency, under Interagency Agreement DOE No. 1824 S581-A1, under contract No. DE-AC05-00OR22725 with UT-Battelle; and contract support was received by Oak Ridge Associated Universities from the U.S. Department of Energy under contract No. DE-SC0014664.

Notes on contributors

John D. Boice

John D. Boice, Jr. is the Director of Science at the National Council on Radiation Protection and Measurements and Professor of Medicine at Vanderbilt University. He served on the Main Commission of the International Commission on Radiological Protection, and on the United Nations Scientific Committee on the Effects of Atomic Radiation. He directs the Million Person Study of Low-Dose Health Effects.

Sarah S. Cohen

Sarah S. Cohen is a Senior Managing Epidemiologist at EpidStrategies, a division of ToxStrategies, and an Adjunct Assistant Research Professor of Medicine in the Department of Medicine at Vanderbilt University School of Medicine. She has been a collaborator on the Million Person Study of Low-Dose Health Effects for nearly twenty years.

Michael T. Mumma

Michael T. Mumma is the Director of Information Technology at the International Epidemiology Institute and the International Epidemiology Field Station for Vanderbilt University Medical Center. He has over 20 years of experience in data analysis and conducting epidemiologic investigations.

Ashley P. Golden

Ashley P. Golden is a biostatistician and Director of ORISE Health Studies at Oak Ridge Associated Universities were she conducts multidisciplinary projects in occupational epidemiology, radiation exposure and dosimetry, medical surveillance, and environmental assessments. She has been a collaborator on the Million Person Study of Low-Dose Health Effects for eight years.

Sara C. Howard

Sara C. Howard is a research associate at Oak Ridge Associated Universities. She has a MS degree in epidemiology and is currently pursuing a PhD in epidemiology with a focus on chronic diseases and occupational exposure. She has been a collaborator on the Million Person Study of Low-Dose Health Effects for nearly three years.

David J. Girardi

David J. Girardi is a scientific computer programmer at Oak Ridge Associated Universities and has been working with the Million Person Study of Low-Dose Health Effects for eight years. He has been a certified Project Management Professional (PMP) for over 5 years.

Elizabeth D. Ellis

Elizabeth D. Ellis is an occupational epidemiologist in the Health Studies group at Oak Ridge Associated Universities. Dr. Ellis does research in Public Health, Occupational Health, and Epidemiology. A major project is contributing to the ‘Million Person Study’. She is also active in human subject protection in research.

Michael B. Bellamy

Michael B. Bellamy is a research scientist at the Memorial Sloan Kettering Cancer Center. Previously he was nuclear engineer and health physics researcher at the Oak Ridge National Laboratory. He served for over 10 years at the Center for Radiation Protection Knowledge specializing in Monte Carlo radiation transport research and internal dosimetry modeling. His current focus is on internal dose reconstruction for the Million Person Study of Low-Dose Health Effects.

Lawrence T. Dauer

Lawrence T. Dauer is an Attending Physicist specializing in radiation protection at Memorial Sloan Kettering Cancer Center in the Departments of Medical Physics and Radiology. He is a Council and Board member of the NCRP and served as a member of the ICRP Committee 3, Protection in Medicine.

Keith F. Eckerman

Keith F. Eckerman is a leading expert in computational and phantom dosimetry, served on ICRP Committee 2, and is an Emeritus Member of the ICRP. He has received several scientific achievement awards, including the 39th Lauriston Taylor Lecturer for the NCRP. He is currently a retired staff member of the Environmental Sciences Division of the ORNL.

Richard W. Leggett

Richard W. Leggett is a research scientist in the Environmental Sciences Division at Oak Ridge National Laboratory. His physiological systems models of the human circulation, skeleton, and gastrointestinal transfer and systemic biokinetic models for many elements are used by the International Commission on Radiological Protection as dosimetry and bioassay models.