'
carcinogenic
-)-
by the Federal hadiation Council.
On the assump-
tion that the induction of cancer is prorortional to radiation
exposure, an estimate of risk cin be made.
Beach and Dolphin,
of the United Kingdom atomic Energy Authority, considering ceveral sources of data, calculated that, on the average, 35 cases
of thyroid cancer may be expected per million persons exposed
to one rad of thyroid radiation.
In terms relevant to the
present testimony, i ia 285 children exposed to 100 rad thyroid
radiation may develop thyroid cancer.
By any standard, this
is an unacceptable risk
Estimates of radiation damuge are difficult, not only
because of the uncertainties of some of the assumptions, but
also because damage does not become evident for muny years
after the exposure has taken piice.
The average latent period
vetween radiation and cancer of the thyroid approximates 10
years; in some instances, the latent period may extend to
20
years.
If the thyroid radiation exposures near the Nevada
Test Site are as righ as suggested in this testimony, careful
medical follow-up of exposed populations might yield evidence
of damage by this “sme
5)
A survey of “he avatlable gamma and beta radiation
measurements of ‘ailout resulting from 31 of the total of 99
tests conducted +1 Nevacs ir. the period 1952-58 shows that
conditions which ‘inde.
the circumstances stated above) lead
to hazardous thyro.d exposures in children have occurred not
only in areas neighboring the Nevada Test Site, but also in
\