32 DISTRIBUTION OF RADIOACTIVE DEBRIS WORLDWIDE EFFECTS OF ATOMIC WEAPONS a) this area. No information is available on the nearby fallout, except from verbal communications indicating that the fallout on other islands in the atoll was not abnormally high and that the islands were safe for occupa3 . § oe = 3 . ° 5 8 8 a «lo i i. | * & 3 bee4 2 g e a 5 x x x x 8 4 ¢ a s a & conn % get|e@ RSA ° 2 5 s . g x g x roe > ~ “3 , tion soon after the shot. Also, large areas of ocean and the whole area within the Iron Curtain were not sampled. Likewise, the polar regions and much of the area below the equator had no samplingstations. In fact, the ratio of the numberof stations to the area outside the continental United States was one station per approximately 4 x 10° mi’. The possibility cannot be ruled out that a large part of the activity may have fallen in a number of areas that were not sampled. Such “hot spots’’ have been observed in the United States from tests in Nevada. On the other hand, since the cloud from MIKE went through the tropo- pause into the stratosphere, and there is evidence that a large portion of the activity may condense out in particles of 0.1 » or less in diameter, it may be that such material will stay suspended in the atmosphere for long periods of time. In support of this hypothesis, it is known that large quantities of dust from the explosion of the volcano Krakatoa stayed suspended in the atmosphere for 2 or 3 years. In this case it is probable Beeeie g&)x x x x|x aElo ec ani|s “AOS RIE , that the dust particles were larger than those from an atomic explosion. IVY Fallout in the United States As mentioned above, the average fallout from tvy in the United States 3 8 3 = 8 a was 1609 d/min/ft’, or a total of 0.0606 Mc, as of January 1, 1953. This 7 es & Bi & so RRS bn o $e 8 e % 8 it is about equal to the total long-range fallout measured for the TUMBLER/ SNAPPER series (0.066 8 Mc). The range of variation in the tvy fallout on the United States was from 4900 d/min/ft’ in Fort Worth, Texas, to 4 ad Z Z Z Zz 420 for both San Francisco and Los Angeles, although measurements at BZa8 a second station in each of thesecities gave 680 and 1000, respectively. The fallout was first observed in the United States 6 days after M-day at g gfort2 represents less than 1 per cent of the total ivy fallout for the world, and . falloutmswas Atlanta, Georgia, at M plus 23 days. SPECULATIONS AS TO THE EXISTING HAZARDS The opinion of nearly everyone who has studied the problem of the