~ae
incidence is small, approximately 2 per 10¢ persons at risk per year per
rad, at least from approximately the second to the fifteenth year follow.
ing exposure (the total number of leukemias following exposure to radiation, from all sources, is only approximately 225 cases to date),
Below
dose levels of approximately 100 r equivalent, the available data are
inadequate for prediction for other than the single acute dose, i.e., it
is not known if a dose-rate dependency exists,
It is not known if the risk
continues beyond approximately the first fifteen years from exposure, although there is evidence that large dose radiation of sizeable portions
of the marrow may be leukemogenic,
There are no adequate grounds for assun-
ing that the highly localized radiation from internal emitters such as Sr98
and radium are leukemogenic.
It is not possible te determine whether a
threshold dose for the induction of leukemia exists.
from exposure to radiation is discussed,
The potential hazard
It is emphasized that the search
for leukemogenic radiation factors, indeed for all harmful environmental
factors, must be on a broad base and not focused upon radiation in general
or the by-products of nuclear weapon-testing particularly.