30 March 1955
Dr. Willard F. Libby
Department of Chemistry
University of Chicago
Chicago 37, Illinois
I see that you and I have been put in the position of apparently being on opposite sides in an argument, in the article in
U.S. News and World Report of 25 March 1955.
You are quoted as saying "The world is radioactive. It always has been and always will be. Its natural radioactivities evidently
are not dangerous and we can conclude from this fact that contamination from atomic bombs, small in magnitude or even of the
same order of magnitude as these natural radiations, is not likely to be at all dangerous."
Perhaps it is not justified to say that the natural radiations evidently are not dangerous. In his paper on the genetic effects
of high energy radiation of human populations Professor A. H. Sturtevant, who is one of the most able and experienced geneticists
in the world, writes that "In particular, there is evidence that irradiation does increase the incidence of leukemia and other
malignant growths." Some biologists, at any rate, think that at least some kinds of cancer are produced by somatic mutations
induced by naturally radioactive potassium, carbon, and perhaps other elements, as well as by cosmic rays. If this is so,
there is little doubt that artificial radioactive substances introduced into the body would also produce these malignancies.
Herman Muller in his 1950 article in The American Scientist, Kurt Stern in Science of 31 December 1954, and Sturtevant all
point out that these radiations without doubt produce harmful mutations. In general these mutations are recessive, so that
their most seriously harmful effects do not show up in the first generation.
Do you have an argument to show that there is no danger that these effects are occurring?
I note that U.S. News and World Report states that radiation exposure to each individual from all tests to date averages no
greater than that produced by one chest x-ray. The point here is that everybody in the world receives this exposure, whereas
only a few people are given chest x-rays. Moreover, the geneticists are disturbed about chest x-rays Sturtevant says "In
general, the conclusion seems warranted that the
medical 'use of x-rays is dangerous, and should be applied with caution and with full realization of the genetic hazards involved."
I shall be interested to read what you feel about my remarks in this letter.
Ava Helen and I are safely back in Pasadena, after some great experiences during our trip around the world.
With best regards, I am