Brn 8 ae co are 6.1 Gli Imereducticn Signifcenee of che | Masch Shot The events following the firmt shat detonsted at the Pacifr preving grounds in 1954, de erribed in thin report, served to emphaniae new problems resulting from the use of atoms weapons. These different effects, the importance of which was only vaguely appreciated , Pi om before, were brought into sharp focus by the present episode. In this chapter the medical problems associated with the use of atomic weapons o¢ nuclear reactor accidents will be discuswed. In particular, the problems asao- ciated with large wale fallout, as they were beought ont in the prevent experience and as they may pertain to the thinking and planning of civil defense, the military and industries emploving nuclear power will be discuseed. Human radiation injury resulting from exposure to fallout and other nuclear radiations will be described, as well as current thought on the diagnosis and treatment of the disease states resulting from exposure to these radiat rons. dent reported here are net necemarily typecal of potential fallow situations in the future. It in clear, hawever, that the cardinal effects te be experted from fallout radiations, aa exemplified by the events described in this report, are clearcut and can be predicted with a reasonable de- gree of awurance. In particular, this accident has emphasized the particulate nature. of the fallout material that renderedit visible in many areas. It should not be inferred that serious fallout will neces- sarily be visible under other conditions of detonation. Also, the chemical nature of the material (calcium oxide) will be encountered in only limited areas of the world. Extrapolation of the Present Findings ww More General Situstions 6.2 It must be emphasized that the large experi- 6.21 6.12 mental nuclear device, the detonation of which led to the exposure of diuaman beings to fallout radiations, was exploded clu 2 to the ground on a tropical coral atoll under peologie and geo- graphic conditions that are significantly dif- ferent from most populated areas of the world. Rach of these conditions, i.e. size of weapon, height of burst, tvpe of terrain, weather con- ditions, presence or absence of water under or near the burst will obviously influence markedly the rate aind extent of contamination by fallout, and the particle size and chemical nature of the fallout material. These factors have been discussed ins official: releases (1-4). It follows, therefore, that the events observed in the acci- Although, as stated in Chapter PIT, the chemical action of the fallout material was considered to have contributed little or none to the effects seen, the tlegree of adhesiveness of the materia) to skin and hair might be quite different with different fallout materia), and in a colder climate where sweating would be minimal. The Effects of Kiloton Weapons Blast and Thermal Effects He fore the problems of fallout associated with Inegaton Weapons are discussed in detail, the Inedieal effect. of kiloton weapons will be re- viewed brietiy for contrast. The effects of such weapons have been considered chiefly in’ the contest of the nominal or 20 KT weapon deto- nated highin the air. (5). The blast and heat effects have been treated thoroughly by Oughtersen et al. (6) and little adelitional comment in required here. Hlast and heat accounted for the vast majority of serious casualties in the Hiroshima and Nagasaki incidents. It should be pointed out, however, that in cities with more substantial dwellings than were present in “gs on to ee eee

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