Cals ¢ This document consists of Copy No. 46 of 19 9 pages Series A ENCLOSURE I UNITED STATES ATOMIC ENERGY COMMISSION WASHINGTON, D, C, January 31, 1955 Admiral Robert B. Carney Chief of Naval Operations OP-00, The Pentagon Washington 25, D. C,. Dear Admiral Carney: Data have come to our attention which indicate thet radioactive debris trapped originally in the North Equatorial current .,.,.Guring Operation CASTLE may be moving via the Kuroshio Current aie“Eoward-the-islands of Japan and Formosa, a possibility which appears to have political as well as scientific significance, In order that we may fully evaluate the information now at hand, detailed monitoring of the Western Pacific must be uncertaken as soon as possible, The purpose of this letter, therefore, is twofold: (1) to inform your office of the nature of the phenomenon which seems to be occurring; (2) to request that a vessel suitable for a survey of 3 ~ 4 weeks! duration be made available and ready to depart from Guam on or about March 1, 1955 with a team of about six scientists to be assembled by the Atomic Energy Commission, The problem can be summarized as follows: 1, One of the important findings during CASTLE was that a large fraction of the radioactive debris from a thermonuclear device detonated close to the surface is deposited within 100 miles of the site of detonation. On the basis of studies we performed after detonations from Dpoth land and barges, it appears probable that more than half of the radioactive debris produced by the CASTLE series of detonations may have fallen into the Pacific in the immediate vicinity of the Marshall Islands, 2, Tne AEC delegates to a Japanese-~American Radiobiolozicel Conference held in Tokyo last Noverber returned to this country with data obtained by the Japenese scientists during the voyaze of the SHUNKOTSU MARU, a research survey vessel which collected ocean samples in the mid-Pacific during the month of May and June, The course of the SHUNKOTSU MARU is attached in Exhibit A which shows pelise-ure A oer Treas eS orp Sree by tv p= ronieiead eS _oot d= STTIE] c_ wwea OROAAS yeapersa Enclosure Ic i a we tS af n € ot” Wry 93