The board desires to say that it has had the fullest cooperation 

 of the task force commander, and that every opportunity has been 

 afforded it in carrying out its mission. The members of the Board 

 have had access to all data thus far accumulated and have had 

 every facility for personally inspecting the results of the test. 



Appendix 1 1 



Preliminary Statement by the Evaluation Board 



on 

 Test B 



The following preliminary statement on Test B was prepared 

 by the Joint Chiefs of Staff's Evaluation Board immediately fol- 

 lowing Test B. The statement was released by the White House 

 on August 2, 1946. 



SECTION I 



Supplement to Preliminary Report on Test "A" 

 In general, the observations on ship damage presented by this 

 board in its first report were confirmed by engineering surveys. 

 The location of the bomb burst, accurately determined from photo- 

 graphs, was such that only one ship was within 1,000 feet of the 

 surface point over which the bomb exploded. There were about 

 20 ships within half a mile, all of which were badly damaged, many 

 being put out of action and five sunk. It required up to 12 days to 

 repair all of those ships left afloat sufficiently so that they could 

 have steamed under their own power to a major base for repair. 

 It is now possible to make some estimate of the radiological in- 

 juries which crews would have suffered had they been aboard Test 

 "A" target vessels. Measurements of radiation intensity and a 

 study of animals exposed in ships show that the initial flash of 

 principal lethal radiations, which are gamma-rays and neutrons, 

 would have killed almost all personnel normally stationed aboard 

 the ships centered around the air burst and many others at greater 

 distances. Personnel protected by steel, water, or other dense ma- 

 terials would have been relatively safe in the outlying target vessels. 

 The effects of radiation exposure would not have incapacitated 

 all victims immediately, even some of the most severely affected 



195 



