THE NATURE OF THE PROBLEMS INVOLVED IN ESTIMATING THE IMMEDIATE CASUALTIES FROM NUCLEAR EXPLOSIONS.

It w a s pointed out tha t cons ide rab le p r o g r e s s h a s been m a d e i n a s sembl ing range -yield-effects da t a f o r nuc lear detonat ions appl icable t o a v a r i e t y of b u r s t conditions and tha t tentat ive though incomple te b iomed ica l c r i t e r i a have been formula ted for a s s e s s i n g the h a z a r d s of exposure t o b l a s t a s we l l as ionizing and t h e r m a l radiat ions. so, it w a s noted tha t g r e a t c a r e m u s t be taken i f meaningful concepts a re to come f r o m a combined u s e of the phys ica l and b iomed ica l data . Even In e m p h a s i s of t h i s fact , the physical ly and biological ly or ien ted p r o b l e m areas w e r e presented and d i scussed . Also , su rv iva l da t a fo r the Hi rosh ima explosion w e r e used t o show tha t the condi t ions of exposure m o r e than any o ther f a c t o r s de t e rmined immedia t e su rv iva l and m o r e than anything e l s e w a s respons ib le fo r keeping the casua l ty f igu res as low a s they w e r e . A m a j o r d e t e r r e n t in applying the expe r i ence in Japan t o a m o r e gene ra l i zed s i tuat ion is the l ack of in format ion about the d i f f e rences between "free -field" p a r a m e t e r s and the envi ronmenta l va r i a t ions tha t w i l l ac tua l ly occur at the loca t ions of people immedia te ly following the bu r s t . The re levant p rob lems a r e complex and difficult and t h e r e h a s b e e n ne i the r widespread apprec ia t ion of the need t o "move out of the streets and into exposure loca t ions" no r with one except ion much progress in t r ans l a t ing "free-f ie ld d o s e " t o t t exposure dose" at locat ions of i n t e re s t . coopera t ive ly by pe r sonne l f r o m Oak Ridge Nat ional Labora to ry and the Atomic Bomb Casual ty Commiss ion . The except ion i s the Ichiban I P r o g r a m being c a r r i e d out A second difficulty in genera l iz ing a c r o s s the range-yield s p e c t r u m of e f f ec t s is the fac t tha t , a l l o the r things being the s a m e , the r a t io s of the m a j o r e f fec ts p a r a m e t e r s t o one another change with yield; v i z . , t h e range -yield-effects c u r v e s fo r t h e r m a l and ionizing rad ia t ion and fo r b l a s t a r e not pa ra l l e l with one another .