NYOO L621 WORLDWIDE FALLOUT FS0M OPERATION CASTLE 1. Introduction During Operation Castle, the atomic weapons tests held in the Spring of 1954 at the Eniwetok Proving Grounds, fallout monitoring vas conducted by the A.E.C. Health and Safety Laboratory (New York Operations Office) ze and the same agencies which had cooperated in earlier surveys. — The work was done in these phases: a. be. c. ' Collection of fallout samples at fixed stations comprising a worldwide network and analysis of the samples at the Health and Safety Laboratory. Similar sampling and analysis of fallout on Navy ships in the Pacific. . Assistance to the task force by the installation and naintenanee of automatic radiation and airborne dust monitors on Pacific Islands, furnishing instruments for aerial monitoring of the islands and providing technical instruction and guidance in the operation of the aerial and ground instruments. a. Investigation of the feasibility of measuring fallout over the open sea. This summary presents the results of fallout sampling at fixed stations. The vork referred to in "c" and "d" above will be reported separatei-. . The fixed station data in greater detail and an analysis of it in rele tion to meteorology will be reported by the Weather Bureau. To simplify data handling, the ship samples were assumed to represent areas into which the ocean was divided for convenience and in which tne © ships happened to be when the samples were taken. . The number ci scir: in each area varied from day to day and the number of days represenvec by samples was different for each area, For these reasons the ship data are not suitable for reporting in summary form. They are best studciei in detail as a part of the general study being made vy the Weather Bure... The ships were used in the sampling program to augment the fixed stations in case a specific question might require dense coverage in some area cf the ocean.