4° UNITED STATES ATOMIC ENERGY COMMISSION Washington 25, De Ce _ Tel. + { ST 3-8000 FOR RELEASE 2:30 P.M. (EDT), Ext. 307 FRIDAY, OCTOBER 12, 1956 . SUMMARY OF Remarks Prepared by, Dr. Willard F. Libby, Commissioner United States Atomic Energy Commission For Delivery befone the American Association for the Advancement Qf Science, Washington, D. C. Friday, October 12, 1956: & 4+ | | 4 CURRENT. RESEARCH FINDINGS ON RADIOACTIVE FALLOUT } ; } The material summarized here is to be given as a speech at the dedication of the new building of the America: Association for the Advancement of Science, radioactive fallout.l/ The subject is The remarks are an:extension of previous discussions. Account is taken of the new information which is constantly flowing in. The theory of the processes occurring during fallout is fuller than that of previous discussions. If one excepts the immediate vicinity and immediate time of tho explosion, the principal hazard is due to the ingestion of radioactive fallout. It is obviously a long time hazard. Of the many radioactive elements present in Rhe debris from a nuclear}-explosion, strontium-90 (Sr°0) pregents the most seripus hazard. The mechanism by which atomic weapon debris is disseminated is discussed. The theory :leads to three kinds of fallout; 1/ first, local. fallout, which is the i The radioactive debris which falls out of the atmosphere after a nucloar explosion is called the radioactive fallout. (mora ) d