Mortality among workers at the Los Alamos National Laboratory, 1943–2017

Abstract

Background

During World War II (WWII), the Manhattan Engineering District established a secret laboratory in the mountains of northern New Mexico. The mission was to design, construct and test the first atomic weapon, nicknamed ‘The Gadget’ that was detonated at the TRINITY site in Alamogordo, NM. After WWII, nuclear weapons research continued, and the laboratory became the Los Alamos National Laboratory (LANL).

Materials and methods

The mortality experience of 26,328 workers first employed between 1943 and 1980 at LANL was determined through 2017. Included were 6157 contract workers employed by the ZIA Company. Organ dose estimates for each worker considered all sources of exposure, notably photons, neutrons, tritium, ²³⁸Pu and ²³⁹Pu. Vital status determination included searches within the National Death Index, Social Security Administration and New Mexico State Mortality Files. Standardized Mortality Ratios (SMR) and Cox regression models were used in the analyses.

Results

Most workers (55%) were hired before 1960, 38% had a college degree, 25% were female, 81% white, 13% Hispanic and 60% had died. Vital status was complete, with only 0.1% lost to follow-up. The mean dose to the lung for the 17,053 workers monitored for radiation was 28.6 weighted-mGy (maximum 16.8 weighted-Gy) assuming a Dose Weighting Factor of 20 for alpha particle dose to lung. The Excess Relative Risk (ERR) at 100 weighted-mGy was 0.01 (95%CI −0.02, 0.03; n = 839) for lung cancer. The ERR at 100 mGy was −0.43 (95%CI −1.11, 0.24; n = 160) for leukemia other than chronic lymphocytic leukemia (CLL), −0.06 (95%CI −0.16, 0.04; n = 3043) for ischemic heart disease (IHD), and 0.29 (95%CI 0.02, 0.55; n = 106) for esophageal cancer. Among the 6499 workers with measurable intakes of plutonium, an increase in bone cancer (SMR 2.44; 95%CI 0.98, 5.03; n = 7) was related to dose. The SMR for berylliosis was significantly high, based on 4 deaths. SMRs for Hispanic workers were significantly high for cancers of the stomach and liver, cirrhosis of the liver, nonmalignant kidney disease and diabetes, but the excesses were not related to radiation dose.

Conclusions

There was little evidence that radiation increased the risk of lung cancer or leukemia. Esophageal cancer was associated with radiation, and plutonium intakes were linked to an increase of bone cancer. IHD was not associated with radiation dose. More precise evaluations will await the pooled analysis of workers with similar exposures such as at Rocky Flats, Savannah River and Hanford.

Keywords:

• Million Person Study
• Los Alamos National Laboratory
• plutonium
• radiation epidemiology
• dosimetry

Acknowledgments

We are indebted to the many individuals who were instrumental in providing support and assistance throughout the conduct of the study of LANL workers employed 1943–1980. Greg Wilkinson (University of Texas, retired) provided advice and the unpublished manuscript by Warren Galke regarding a follow-up of the Zia workers who were included in our investigation. Drs. Luis Bertelli, John Klumpp and other colleagues at LANL were instrumental in providing updated plutonium bioassay urine results that we could incorporate into the dose reconstruction for individual workers. The Department of Energy Office of Environmental Health and Safety (Drs. Pat Worthington, Bonnie Richter and Joey Zhou) provided essential support for accessing DOE occupational records, including autopsy material from the USTUR. Drs. Sergei Tolmachev, Maia Avtandilashvili and Martin Šefl (USTUR) provided helpful insights into the organ doses received from plutonium among LANL workers as well as biological data on autopsy materials which helped validate the biokinetic models used. Dr. Mary Shepherd at the New Mexico State Health Department facilitated our independent linkages for vital status death determination. Linda Walsh (University of Zurich) provided helpful guidance on Poisson regression risk modeling and estimation. Laurie Wiggs (LANL, retired) provided important early guidance with regard to our follow-up of her previous studies. Ray Guilmette (formerly at Lovelace and LANL) provided critical early guidance with regard to the plutonium bioassay program at LANL. We are further indebted to Craig Yoder and Chris Passmore (Landauer, Inc.) for facilitating record linkage of career doses, Derek Hagemeyer (ORAU) for facilitating the career dose linkages for the REIRS and REMS data registries, and the U.S. Army Dosimetry Center (William S. Harris, Jr., CHP), the U.S. Air Force Radiation Dosimetry Laboratory (Ms. Linda Wilson), and the Naval Dosimetry Center (CAPT Thad Sharp and LCDR Nakima McCormack) for facilitating linkages with their respective military dosimetry files. The findings and conclusions in this paper are those of the authors. Its publication does not necessarily represent the official positions of or implied endorsement by the National Council on Radiation Protection and Measurements, Oak Ridge Associated Universities, Vanderbilt University Medical Center, 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 Los Alamos National Laboratory, a component of the Million Person Study, was financially supported in part by grants from the U.S. Department of Energy [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 [DE-AU0000042, 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, 80NSSC19M0161]. 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 is past President of the National Council on Radiation Protection and Measurements and Professor of Medicine at Vanderbilt University. He is an international authority on radiation effects and 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, Inc., where she directs observational research studies in the areas of pharmacoepidemiology, nutritional epidemiology, and occupational epidemiology as well as leads large data management projects and statistical analyses. She is also 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 20 years, providing analytic support as well as coauthoring numerous publications.

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. He has published on methodological topics, including geocoding and comprehensive radiation exposure assessment, and is currently developing methods to determining socioeconomic status based on residential history.

Ashley P. Golden

Ashley P. Golden is a senior biostatistician and Director of ORISE Health Studies at Oak Ridge Associated Universities where 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 8 years.

Sara C. Howard

Sara C. Howard is a research associate at Oak Ridge Associated Universities. She has a masters 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. He has over 20 years programming experience working with epidemiologists and statisticians and has been working with the Million Person Study for over seven years. He is a member of the Project Management Institute and has been a certified Project Management Professional (PMP) for over 8 years.

Elizabeth Dupree Ellis

Elizabeth Dupree Ellis is a senior occupational epidemiologist and Associate Director of ORISE Health Studies at Oak Ridge Associated Universities. She has been studying the health effects of chronic low dose ionizing radiation on the Department of Energy nuclear workers for over 40 years and has been a collaborator on the MPS for over 10 years. She is a member of an International Commission of Radiation Protection Task Group reviewing the health effects of alpha emitters. She is also active in protection of human participants in research serving on several Institutional Review Boards.

Michael B. Bellamy

Michael B. Bellamy is a nuclear engineer and health physics researcher at the Oak Ridge National Laboratory in the United States. He has served for over 10 years at the Center for Radiation Protection Knowledge specializing in Monte Carlo radiation transport research and internal dosimetry modeling. He is currently focused on internal dose reconstruction for the NCRP Million Person Epidemiology study with the end goal of deciphering the relationship between health effects and chronic radiation exposure to U.S. radiation workers. Dr. Bellamy’s research supports several federal entities including the Centers for Disease Control and Prevention, the U.S. Department of Energy, the U.S. Nuclear Regulatory Commission and the U.S. Environmental Protection Agency.

Lawrence T. Dauer

Lawrence T. Dauer is 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.

Caleigh Samuels

Caleigh Samuels is an assistant staff member in the Center for Radiation Protection Knowledge at Oak Ridge National Laboratory. She received her BS in physics from Radford University, her MS in medical physics from Georgia Institute of Technology in 2018 and is currently working toward her PhD in nuclear engineering. Her research focuses on developing and enhancing biokinetic models used in radiation protection and dose reconstruction and application of advanced Monte Carlo techniques in dosimetric modeling. She collaborates on the Million Person Study and is currently focusing on organ dose reconstructions following plutonium intakes at the Rocky Flats nuclear facility.

Keith F. Eckerman

Keith F. Eckerman retired in 2013 from Oak Ridge National Laboratory and is an emeritus member of the National Council on Radiation Protection (NCRP) and Committee 2 of the International Commission on Radiological Protection (ICRP). He has over 40 years’ experience in radiation protection having worked at Argonne National Laboratory, the Nuclear Regulatory Commission, and Oak Ridge National Laboratory. He served on ICRP Committee 2 for over 20 years and chaired their task group on dose calculations.

Richard W. Leggett

Richard W. Leggett is a research scientist in the Environmental Sciences Division at Oak Ridge National Laboratory (ORNL). His main research interest is in physiological systems modeling, with primary applications to the biokinetics and dosimetry of radionuclides and radiation risk analysis. He is a member of Committee 2 of the International Commission on Radiological Protection (ICRP) and the ICRP Task Group on Internal Dosimetry (INDOS). His physiological systems models of the human circulation, skeleton, and gastrointestinal transfer and his systemic biokinetic models for many elements are used by the ICRP as dosimetry and bioassay models. He is the author of ICRP Publication 70, Basic Anatomical and Physiological Data for Use in Radiological Protection: The Skeleton, and coauthor of several other ICRP reports.