Cancer Mortality Among Uranium Mill Workers

Our plain-English summary of Cancer Mortality Among Uranium Mill Workers, by V.E. Archer, J.K. Wagoner, F.E. Ludin JR (1973).

The study

• Authors: V.E. Archer, J.K. Wagoner, F.E. Ludin JR
• Published: Journal of Occupational Medicine, Volume 15 No.1, January 1973.
• Type of article: Journal article
• Our copy: from Johns-Manville's own medical library. The article is still under copyright, so we describe it here rather than post it.

In plain English

This study is about uranium mill workers. It does not concern asbestos. The authors followed 662 white men who were working in one of six uranium mills when the US Public Health Service examined them in 1950, 1951 and 1953. They recorded deaths through December 31, 1967, and compared them with the number expected from death rates for white men in Colorado, Utah, New Mexico and Arizona. There were 104 deaths, about the same as expected overall. The authors judged that one cause showed a meaningful excess: malignant disease of the lymphatic and blood-forming tissue other than leukemia, mostly lymphomas. This involved five men, and the authors noted the numbers were small. None of these five worked near the fusion furnaces, so the authors set aside vanadium as a cause. Drawing on animal experiments, the authors concluded that the excess may have resulted from irradiation of lymph nodes by thorium-230. They called the finding tentative and said a larger study was under way to confirm or reject it.

We wrote this plain-English summary from the full article with the help of AI, and a second AI model checked each sentence against the article. It is not the authors' wording; the abstract and the article are their own account.

What the study did and found

• Design: Mortality follow-up (cohort) study of examined workers, using person-years and comparison of observed with expected deaths
• Who was studied: 662 white men working in one of six uranium mills when examined in 1950, 1951 or 1953, followed to December 31, 1967. Expected deaths came from the white male population of Colorado, Utah, New Mexico and Arizona.
• Exposure: Work in uranium mills. Suspect ore constituents named by the authors were vanadium and long-lived members of the uranium radioactive decay series, including uranium-238, uranium-234 and thorium-230. No asbestos exposure is discussed.
• Main results:
  • From 1950 through 1967 there were 104 deaths among the mill workers, nearly the same as the number expected from area rates (about 105).
  • The authors judged that the excess of deaths from malignant diseases of the lymphatic and hematopoietic tissue other than leukemia appeared meaningful, though the numbers were small. Five men were involved.
  • A deficit of ten deaths from 'all other causes' was thought by the authors to have little meaning, because it was spread across miscellaneous causes.
  • The men who died of these lymphatic and hematopoietic malignancies had relatively short mill work. None had worked at the product end or near the fusion furnaces.
  • Urine uranium in 249 examined mill workers averaged about 8 micrograms per liter. 59 air measurements in two mills had a median of 110 micrograms per cubic meter, with values up to 5100.
  • No excess malignant disease of the liver, lungs, kidneys or bone was observed.
• The authors' conclusion: The authors concluded that, based on animal data, the excess may have resulted from irradiation of lymph nodes by thorium-230. They considered vanadium removed from suspicion and called the finding tentative.
• Limitations the authors state:
  • The numbers of deaths involved were small.
  • Thorium-230 exposure could not be quantified for the five men or the whole group; only a rough estimate was possible.
  • The finding is tentative and needs confirmation by a larger study.

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