caeried to these heighte, and « large number of the total particles eculd have been large enough to cvercride any tropopause trapping action that may exist. In any event, use of this method more nearly describes the BRVO results if altitudes up to 0,000 fees are considered. (6) CROSSAOLDS RI was used to obtain an appresiation of the lagoon contastnation which could be expected. This information together with other studies (Tab F) gave rise to the assumption that the phenomena would be more an operational cuisance than a hasard, It wee aseumed that ship operation could begin in the lagoon (exsept within a few miles of Ground Zero) by D plus 1 day, or at least by D plus 32 days. to be valid aseumptions. ‘These proved Work began by et least D plus 1 day on ali shots, and, emept for BRAY, re-entry to the Nill anchorages was not prohibitive on the shot day itself, No appreeiable radiation we enscuntered at the- anchorages, exsept following UNEEE, wien water intensities one foot fram the surface were ebout 20ar/br at the 0 anchorage a6 plus 10 hours. Nevertheless, the major ships were brought back’ in following thig shot for re-grouping of perecanel, following ied ali ships departed the lagoor,. eane to ENIWSTOK, the others to remain at sea cverenight, In general; it appears that the lagoon ecntaminatian ensauntered was that due primarily tofall-out and very little (except along western reefs) due to cireulation. Prinsipally, there appeared to be Littre oF no upwelling of sontamination vy eireulation, and consequently no appreciable spread of contamination by eyolie re-cirmlation of the lagoon, (See fab J for further description of ship operation in the presence of significantly ecntazined water.) swe ey 59