26 January 1962
Dear Mr. President:
I urge that you not order the resumption of atmospheric tests of nuclear weapons by
the United States.
So far the United States has carried out about twice as many test explosions of nuclear
weapons as the Soviet Union. The megatonnage of the bombs tested by the Soviet Union
is about 60 percent greater than that of the bombs tested by the United States, but
it is the number of tests, rather than the total megatonnage, that determines the
amount of information obtained. There is no doubt that the United States still has
a great lead over the Soviet Union in nuclear weapons technology.
It is not necessary for the protection of the United States and the American people
for our government to resume nuclear testing in the atmosphere.
There is general agreement among biological scientists about the biological effects
of radioactive fallout. No one can deny that the fission products produced by these
tests in the atmosphere cause genetic mutations that will lead to the birth of grossly
defective children. The number of defective children produced by these fission products
and by high-energy radiation in general cannot be accurately estimated. The estimates
made by the most reliable American geneticists, agreeing also with the estimates of
the United Nations Committee on this subject, are in the neighborhood of 1,000 grossly
defective children per megaton of fission.
Moreover, the carbon 14 produced by the neutrons released in the explosion, even in
the explosion of so-called "clean" bombs, will, according to the most reliable estimates,
produce a considerably larger number of defective children than the fission products,
provided that the human race continues to exist on earth during the lifetime of the
In addition, many scientists, although not all, think that it is highly probable that
radioactive fission products and carbon 14 damage human beings now living, as well
as those of future generations, in such a way as to cause leukemia, bone cancer, and
I have no doubt that we could destroy the Soviet Union with the bombs that we now
have, even after an initial attack, and I believe that our danger would not be at
all increased by our refraining from bomb testing for the foreseeable future. In
the meantime, our efforts toward achieving peace and disarmament would be made more
effective by our moral position and by our enhanced standing with the neutral nations
if we were to refrain from carrying out any further tests of nuclear weapons.
I urge that further testing of nuclear weapons not be ordered, and that instead an
increased effort be made to achieve a bomb-test agreement, with international controls
and inspection, and other agreements leading to the goal of general and complete disarmament
with control and inspection.