1.4 THE TESTING PERIOD 1.4.1 Nuclear Tests After World War IIL, field testing of nuclear devices first occurred at Bikini Atoll during Operation Crossroads in 1946. Tests Able and Baker were conducted there in June and July of that year. In July 1947, the Atomie Energy Commission announced that it was "establishing proving grounds in the Pacific for routine experiments and tests of atomic weapons." Operation Sandstone was conducted during April and May 1948, at Enewetak Atoll. This series of tects consisted of three devices detonated atop 200-foot steel towers, one each on islands Janet, Sally, and Yvonne. Figure 1-3 shows where each of the 43 tests was conducted during the entire test period from 1948 through 1958. Table 1-3 summarizes relevant data on all tests conducted at Enewetak. The next series of tests was conducted in Operation Greenhouse during April and May 1951, when four more devices were placed on steel towers and detonated. Island Janet was selected for two of the tests, while Ruby and Yvonne were each sites for one test. Tests Mike and King were conducted during Operation Ivy in the fall of 1952. Mike was the first thermonuclear device tested by the United States. Island Flora (Elugelab) was selected for the test; a crater in the reef about one mile across and 180 feet deep now marks the spot where Flora used to be. Operation Castle involved only Test Nectar at Enewetak in May of 1954, but five other large-yield tests were conducted at Bikini, including Test Bravo, rated at 15 million tons of TNT and the most powerful device detonated by the United States to that time. In terms of the number of tests conducted, the pace of activity was significantly increased two years later during Operation Redwing when 1] devices were detonated at Enewetak and 6 more at Bikini. Redwing was the last series to utilize a steel tower for device placement. Towers were constructed on four islands with two on Sally, two on Yvonne, and one each on Ruby and Pearl. Surface tests were conducted on Yvonne, where the Lacrosse Crater now is, and on Irene where the Seminole Crater was produced. Testing of nuclear weapons and other devices by the United States, Russia, and Great Britain had, by 1956, produced worldwide fear of the hazard created by radioactive fallout. participation in discussions with the other nuclear powers in Geneva, Following U.S. Switzerland, President Eisenhower announced in August 1958, that the U.S. would negotiate with any other country suspension of nuclear weapon tests. The offer was accepted by the USSR and a moratorium on testing was set at 3] October 1958. The United States had anticipated the possibility of a halt to testing, so had assembled a large array of devices to be tested before the start of the moratorium. Operation Hardtack, Phase I, conducted in the Pacific from April through August 1958, included 22 tests at Enewetak, 10 at Bikini, 2 in the Johnston Atoll area, and one at 86,000 ft. over the sea between Enewetak and Bikini. In addition, three tests were conducted in the South Atlantic during August and September in Operation Argus. Operation Hardtack, Phase IL took place at the Nevada Test Site in September and October 1958, with the detonation of 18 nuclear devices, By the time the test moratorium became effective, the U.S. had conducted 43 tests at Enewetak, 22 of them in 1958. The Enewetak tests of 1958 included 16 devices detonated on barges, 7 in the lagoon southwest of Janet, 8 in the lagoon west or southwest of Yvonne, and 1 on the reef southwest of Alice. Two underwater tests were conducted to the southwest of Enewetak Island, one in the lagoon north of Glenn, and one in the ocean south of James. Surface tests included Cactus, which formed the Cactus Crater on the north end of Yvonne; Koa, which formed a very large crater where Gene used to be; and Quince and Fig in the north central part of Yvonne. The Quince and Fig tests were responsible for spreading unburned plutonium fuel over a large area of Yvonne. No additional tests were conducted at Enewetak or Bikini. 10