§ Mr. Fortasked the Secretary of State for the Home Department how far, in the current review of civil defence plans, account is being taken of the data made available by Dr. Willard Libby, of the United States Atomic Energy Commission, as to the effects of fall-out from a hydrogen bomb over an area of 100,000 square miles.
§ Major Lloyd-GeorgeI am glad to have the opportunity of correcting misunderstandings that appear to have arisen from necessarily abbreviated summaries of Dr. Libby's remarks. The total fission182W products from bombs of the same type and power are always constant. Therefore the larger the area over which those fission products fall, the lower will be the average intensity of radiation. The full text of Dr. Libby's statement shows that he quoted the area of 100,000 square miles as a simple illustration. His calculations assumed the total contamination to be spread uniformly, which in practice could not occur.
The result of assuming a uniform spread over such an area is that the degree of contamination would be everywhere lower—and therefore much less dangerous—than if the bulk of the fallout had been concentrated in a very much smaller area, as happened in the case of the Bikini test, where the area of high concentration was of the order of 7,000 square miles. Dr. Libby's theoretical calculations are not in any way inconsistent with the figures given in the February Report of the United States Atomic Energy Commission, on which civil defence plans are being worked out as part of the general review at present in hand.