Edward Lewis and radioactive fallout: the impact of Caltech biologists on the debate over nuclear weapons testing in the 1950s and 60s

摘要

The work of Caltech biologists, particularly, Edward Lewis, on leukemia and ionizing radiation transformed the public debate over nuclear weapons testing. The United States began testing hydrogen bombs in 1952, sending radioactive fallout around the globe. Earlier more localized fallout was generated starting in 1945 from tests of atomic weapons at Nevada test sites. The Atomic Energy Commission claimed the tests would not harm human health. Geneticists knew from animal and plant experiments that radiation can cause both illness and gene mutations. They spoke out to warn the policymakers and the public. Edward Lewis used data from four independent populations exposed to radiation to demonstrate that the incidence of leukemia was linearly related to the accumulated dose of radiation. He argued that this implied that leukemia resulted from a somatic gene mutation. Since there was no evidence for the existence of a threshold for the induction of gene mutations down to doses as low as 25 r, there was unlikely to be a threshold for the induction of leukemia. This was the first serious challenge to the concept that there would be a threshold for the induction of cancer by ionizing radiation. Outspoken scientists, including Linus Pauling, used Lewis?s risk estimate to inform the public about the danger of nuclear fallout by estimating the number of leukemia deaths that would be caused by the test detonations. In May of 1957 Lewis?s analysis of the radiation-induced human leukemia data was published as a lead article in Science magazine. In June he presented it before the Joint Committee on Atomic Energy of the US Congress