52 RADIOLOGICAL CLEANUP OF ENEWETAK ATOLL | ; Description and History: 1526-1972 53 depth of 500 feet in the ocean, the second at a depth of 150 feet in the lagoon. All other events were barge events in the lagoon, with the exception of the Oak Event which, although a barge shot. was carried out on the western reef. Construction of one of the scientific stations on Runit for the Hardtack series is shown in Figure !-52. The events conducted during Hardtack I represented slightly more than 50 percent ofall nuclear tests conducted at Enewetak. They also were the last nuclear explosions to occur on either Enewetak or Bikini. Figure |-53 shows the locationsof all test events that were detonated during nuclear testing at Enewetak Atoll.85 MORATORIUM AND TEST BAN | FIGURE 1-51. EVENT KICKAPOO SHOT TOWER, AOMON. Soviet Union, Poland, Romania, and Czechoslovakia. The final report Stated that it would be ‘‘technically feasible to set up, with certain ate ‘aiiin ) . a . iPin Vn Though international discussions had been opened on the cessation of the AEC and DOD announced ijnTae 4 at pik OPERATION HARDTACKI: APRIL-AUGUST 1958 atmospheric nuclear testing, A conference to explore methods of detection of possible violations during a potential suspension of nuclear weapons testing was held in Geneva, Switzerland, from | July through21 August 1958. The attendees included the United States, the United Kingdom, Canada, France, the on 15 i 7 September 1957 that, in the absence of a disarmament agreement, the U.S. _; an a a ne would continue testing in the Pacific with the conduct of the Hardtack J series, beginning in April 1958, Hardtack I consisted of 34 events, 22 of which were at Enewetak, two in the Johnston Atoll area, and ten at Bikini. Thefirst event of the Hardtack I series was carried by balloon to a height of 86,000 feet and detonated over the ocean about 80 miles northeast of the atoll. This event, Yucca, is not classified as an Enewetak shot since it occurred between Enewetak and Bikini. Three surface events took place ice i fi ar fi i Sia ida ee HA i in Ht WN on Runit, and these were to produce significant effects. Cactus Event , } 2 . £ bil ; Q . Li E { widespread surface and subsurface contamination of northern Runit. A fourth surface event, Koa, 137 MT, was carried out on Lidilbut, vaporizing it in the same manner that Mike had removed Elugelab. Two events, Wahoo and Umbrella, were conducted underwater, the first at a ' Oe 1 wee ee f FIGURE 1-52. EVENT HARDTACK SCIENTIFIC STATION 1310, RUNIT.