cases to produce evidence of injury; hence, a higher threshold for
cancer production than that for minimal damage from an acute dose.
Skin cancer production shows little radiation time-intensity dependence
and, like the genetic effect to be discussed later, the incidence is
probably a linear function of total dose.
The measures which may be taken to prevent beta burns of
sufficient severity to reduce the efficiency of military or civilian
populations are quite simple and effective.
The cornified layer of
skin covered with loose fitting clothing provides the minimm protection necessary to prevent serious injury to the living layers of the
skin.
Brennan and his co-workers have reported the following thick-
nesses for standard items of Army apparel:
Item
Mgm/ m=
Undershirt
Shorts
17
12
Trousers
77
Shirt
Field Jacket
2
186
O"
x
0.6
Ao
From beta range considerations, it can be shown that the above
items of clothing can effectively protect against beta energies from
O.1 mev to 0.6 mev.
The protection afforded by ordinary clothing is
easily augmented by wearing gloves and by frequent washing with soap
and water when working in an area of fall-out or suspected contamination.
The Genetic Problem.
In considering the genetic problem due
to local fall-out, the probability must be considered that "local" may
involve an entire nation such as the United States in the event of an
atomic war.
For surface bursts, approximately 50% of the fall-out
radiation has been accounted for locally.
The radiation risk at early
times after fall-out has begun is greater than at later times due to
the decay characteristics of fission products.
These two facts ind-
cate that potentially at least the genetic problem due to total fallout may be primarily determined by the effects brought about in
89