To the Editor of the New York Times:

I have read with interest the letter from Drs. J. Laurence Kulu,

Wallace S. Rroecker,  and Arthur R.  Schulert  in your issue of 2 May 1.958.

In this letter they say that my statement that carbon 14 represents "a far

more serious long-term menace than all other radioactive by-products of

                                                                _ -
     **
an atomic explosion" is incorrect, and

                 . .
[ that car'bon 14 will contribute only a
               F

minor fraction of the radiation produced by strontium PO and cesium 137.

et%en the cumulative w dose to the entire population over

the total lives of all isotopes is considered, the radiation from the

                                           .         .
carbon 14 produced by bomb tests V is found to be La+

considerably larger than the amount attributed by the ARC to other isotopes,

and the number of defective children that can be predicted to be pro-

duced by the radiation from carbon 14 is far greater than the number

predicted for the other isotopes.

In his 1956 paper on radioactive fallout Dr. W. F. Libby pointed

out that neutrons released in the explosions of nuclear weapons in air

react with nitrogen nuclei to make carbon 14; he said that "mrtunately


-2-

safe

this radioactivity is essentially/because of its long lifetime and the

enormous amount of diluting carbon dioxide in the atmosphere."  Perhaps

because of a feeling of reassurance engendered by this 4 statement and

others by Dr. Libby I did not make any calculations of the genetic and

somatic effects of the carbon 14 produced in the testing of nuclear

weapons until last month.

Dr. Libby gave additional

including m a

statement &k&x about the amount of carbon 14 generated per megaton,

with fusion and fission weighed as they had actually occurred; this

amount is 7.4 kilograms, about 7 times the amount that he had reported

in 1956 for a pure fission weapon.  He stated that a considerable part

of the carbon 14 (which I estimate as two-thirds) falls back as calcium

of which the biosphere

is a part.  At the present time the concentration of carbon 14 in the


                                      to

atmosphere has been increased by the bomb tests 3q a value 10 percent

greater than its former value.  As carbon dioxide dissolves in the ocean,

I shall calculate the effect of carbon 14 on the basis of the following
     74 -4          ,L.o
assumptions: +3&z&~M       of bomb testing A 30 megatons per year;


3

one-third of the generated carbon 14 is released to the atmosphere; there is

moderately rapid equilibrium with a large reservoir, including the ocean,

with normal content 74,000 kilograms of carbon 14; the mean life of carbon

14 is 8070 years'  e effect of a single gonad exposure of 0.1 roentgen

of a world population equal to that at present is to cause ultimately a

total of 380,000 seriously defective children (gross physical or mental
                  d

defect, stillbirth, childhood death) plus 700,000 embryonic neonatal
                               4

deaths, as @.XTQE estimated by Professor James F. Crow, a member of the

National Academy of Sciences-National Research Council Committee on Genetic

Rffects of Atomic Radiation, in his testimony before the Congressional

Subcommittee on Radiation on 4 June 1957; the population of the world,

over

which has increased by/l billion during the last 100 years will
                          3    continue

will have an average value during the next 10,000 or

20,000 years such that there will be five times as many children born as

al amount of carbon 14 in the human body produces a

gonad exposure of 0.0015 roentgen per year., as stated in 1956 hy Dr. LibbQ

  A straightforward calculation based on the above assumptions leads

directly to the conclusion that 1 year of testing at the standard rate


4

of 30 megatons per year (wz&axxam two 15-megaton bombs, similar to the

one detonated by the United States on 1 March 1954) will ultimately be
          ?3O,@W
responsible for the birth of m seriously defective children and

also for k@,OOO embryonic and neonatal deaths.

For comparison, we need to have a value of the amount of radiation

produced by the other isotopes.  fepig The calculation of the effect of

other isotopes is most readily made by the steady-state method.  In the

NAS-NRC report of 4 June 1956 it is said that if weapons testing were

continued at the rate of the preceding five years it is estimated that

a total 30-year gonad dose of about one-tenth of a roentgen would be

produced, or, since the accuracy involved is probably not better than a

factor of 5, a dose between 0.02 roentgen and 0.50 roentgen. The value

in 30 years

0.1 roentgen/has been reported as recently as 73kkxxxxx this year., 1958,

in the 23rd Semi-annual Report of the Atomic Energy Commission.  It cor-

respnds to 0.0033 roentgen per year , and accordingly to the production

of 13,000 seriously defective children plus 23,000 embryonic and neonatal

as the


5

carbon 14W per year of testing , and accordingly the statement is justi-

                                 genetic

fied that carbon 14 is a far more serious long-term/menace than the other

products of atomic explosions.

Although the Atomic Energy Commission has not released any statement

about this matter, it seems to me not unlikely that the world-wide fallout

corresponds more closely to the upper l&nit given by the NAS-NRC committee,
             tw+L 0

0.5 roentgen in 30 years, than to the ~W&~FS value I\ If the upper limit is

number of embryonic and neo

These numbers

are still far less than those estimated for +kh carbon 14,@Wm+. On

the other hand, it must be pointed out that if the world population

remain{ /
    constant the effect of carbon 14 would be only about equal to

that of the other isotopes , assuming that the other isotopes irradiate the

gonads in amount 0.5 roentgen in 30 years, rather than the usually quoted

value 0.1 roentgen in 30 years.

The somatic effects of the bomb tests are more difficult to discuss,

because they involve more assumptions about the nature of the interaction


6

because xz&xxU scientists

are not in such overwhelming agreement as they are about the genetic ef-

fects.  I shall content myself with the statement that it is likely

                       in the long run,
that the somatic effects of carbon 16 are/roughly equal to those of the

other isotopes, including strontium 90.

!Ihe bomb tests carried upl+canit including 1958
      c      3        t
                 loyIc

off as a bad year) can be estimated to correspond roughly to  30-megaton

????? o  Accordingly we may say that the predicted effect of the carbon

         these

14 released in UGZ bomb tests will be to produce about 1 million seriously

defective children and about 2 million embryonic and neonatal deaths,

and that the predicted effects of the other

will be v

As other

fraction of the

people have pointed out, these numbers represent a minute
                A

total number of seriously defective children

&%&S&J and of embryonic and neonatal deaths


7

E
     I feel that

each

human being is important, and that it is well worth while

to calculate the numbers of individual human beings who will be caused

to suffer or to die because of the bcmb tests, rather than to talk about

"negligible effect / ,lr "undetectable increase, tr llextremely m&L1 fraction."

Linus Pauling

Pasadena, California