CONFIDENTIAL.
(c) Although the proportion of deaths from fallout increases slightly with the cep
ee
of the attack, the deaths from fallout alone are a very small proportion of the deaths from
the attack as a whole. This finding is borne out also in App C of this report.
It should be emphasized that. the figures cited here assume no evacuees from urban
targets, but are based on the relatively sparse rural and small town populations residing in
the area.
TABLE 9
Dearus FROM FaLLout aS Funcrion or Arrack
Sizz, CEP, anp Season
Deaths, thous
Bombs
CEP
4000 m
CEP
8000 m
CEP
12,000 m
Summer
2
4
7
73
220
262
2
4
7
12
490
470
Winter
78
200
261
72
103
246
76
138
282
22
245
323
Additional from blast and thermal effects, any season
2
4
7
2361
3001
3401
1742
2074
3438
510
1056
1214
FALLOUT AND EVACUATION
It is now possible to estimate the numberof additional deaths from fallout that can
be expected as a function of 1- or 3-hr evacuation radiating outward from thecity.
Figure 27 indicates that for a 4000-m cep attack 12 percent of Washington’s population would be killed by a single weapon whenthe civil defense tactic was 1-hr evacuation,
and 9 percent when the tactic was 3-hr evacuation.
Figures 30, 32, and 33 show actual
Gz for a 4000-m cer summerattack of one, two, and four bombs on the Washington target.
Using Fig. 10 as a guide to the new population concentrations created by 1-hr evacuation,
it is apparent that approximately 33 percent of the city’s population who were notkilled
by blast and thermaleffects would be exposed to a dose of 500 r. Allowing an attenuation
factor of 0.5 for shelter equivalent to an automobile or shed-type building, and applying
a mortality coefficient of 0.05 for the corrected dose of 250 r, a new estimate of at least
14 percent instead of 12 percent is appropriate when 1-hr evacuation is the civil defense
tactic.
The disadvantages of evacuation becomestriking when the number of bombsincreases.
Figure 33 indicates that for two bombs per target approximately the same percentage of
the evacuating population would be exposed to 500 r as for one bomb,resulting in a revised
estimate — 51 percent mortalities instead of the 22 percent computed whenfallout was not
considered. With four 10-Mt ground bursts, as indicated in Fig. 30, all but perhaps 15
percent of the population of Washington is destroyed by either blast or thermal effects or
lethal degrees of radiation.
ORO-—R-17 (App B)
45