May 12, 1971

Dr. Marvin A. Schneiderman
Associate Scientific Director
for Demography (Acting)
Mational Cancer Institute
Bethesda, Maryland 20014

Dear Dr. Schneiderman,

Thank you for your comments of May 6th about ay piece in the
Washington Post, May 2. Needleas to say, it was hardly feasibie
to develop a detailed quantitative srgument in that vehicle.

Gf course I agree with you that one must calculate differential

rather than integral costs in assessing the risks of incwemesehi <<

radiation exposure, We also have to conaider many other sore
complicated interactions « is the fraction of the pepulation that
will receive the highest exposures likely to be biased towarde
higher or lowex vulnerability to radiation on account of other
genetic and environmentel factors? However, if nuclear energy is
in fact going to be kept within a 1 millirad average limit a large
part of the recent debate should evaporate, If we are going to be
concerned about 1 millirad increments there are obviously many
more cogent targets for that concern.

There still remain all the other problems of safeguard against
major catastrophies which I do not feel very competent to judge.
and, of course, besides the problem of populationsal hazarda there
must also be standards for individual exposure + we could hardly
justify involuntary riske vithout compensation, However, as I tried
to bring out with my example of the "10 millirad householder” there
are levels of risk which remain socially important although
individually inconsequential.

A great deal of wy thinking on the question can be suamarized
with the surmise that the differential cost of radiation is about
$100 per man-rad. If you think this is low by a fector of 10 it still
would not particularly alter our policy conclusions. If it under-
estimates the eee@ cost by a factor of 100, about which I would be
ekeptical, we would have to start thinking about shielding ourselves
from the natural background, altitude effects, and alike. I do not
see that the calculated differences between integral and differentiel
costa could matter anything like a factor of 10.

q
n

Cede \
Dr. Marvin A. Schneiderman ~2- 5/12/71

I would certainly agree that “unnecessary diagnostic radiation"
is the most relevant target fér our concern at the present time,
I am not sure that we have a clear picture of the individual and
social benefits of most of that radiation,of the kind that we would
need to have to label it as “unnecessary”. Certainly this needs to
be looked into very carfully, I would very strongly support stringent
regulations on that kind of radiation exposure which is un-
necessary insofar as it is a byproduct of technical stinginess
and makes no contribution whatever to the diagnostic process,
Suggested regulations requiring x-ray machines to be equipped with
field-defining devices whould have a very high prftority and would
be very easy to justify on the basis of the $100 per man-rad criterion,

Sincerely yours,

Joshua Lederberg
Professor of Genetics

IL/rr