The bioenvironmental condition of Rongelap was unique. The fallout had made the atoll the only place in the world contaminated on a single occasion by relatively heavy deposition of radioactive debris without also being disturbed by a nuclear explosion. In 1957-1958, after the Rongelapese had been returned to a new village constructed on their atoll, Rongelap was the site of a long and thorough study of the circulation of radionuclides in the terrestrial-aquatic environment. Before the 1963 Test Ban Treaty The first break in the pattern of nuclear testing came in 1958, when the nuclear powers agreed to a 1-year test moratorium. The world’s political and emotional climates were changing. For more than 5 years, the United States, which had announced its Atoms-for-Peace Program in December 1953, had been endeavoring to place emphasis on the use of atomic energy for constructive purposes. The Atomic Energy Act of 1954, liberalizing provisions of the 1946 law, contemplated for the first time private development of nuclear power resources and established authority for international activities. In 1957 the Atomic Energy Commission initiated its Plowshare Program for the development of peaceful uses of nuclear explosives.[11] [Illustration: _Distribution of fallout radioisotopes on Rongelap Atoll as determined by a survey in 1961. Note the interrelationships of man, plants, animals and the environment._] Amid such changes there was arising, too, a wider apprehension concerning the possible effects of fallout. The United Nations in 1955 appointed a committee of scientific representatives of 15 nations to study the effects of radiation on man. In the United States the National Academy of Sciences published in 1956 the first of its summary reports on the biological effects of atomic radiation. Nuclear testing was not ended by the 1958 agreement, yet the moratorium—which was renewed annually until 1961, when the U.S.S.R. broke the agreement by initiating a new test series—was significant as an experiment in nuclear restraint. After the United States conducted a final test series near Christmas Island in 1962, new discussions of ways to halt successive rounds of nuclear test programs were held. Finally, in 1963, the Nuclear Test Ban Treaty was signed by most of the nations of the world. The treaty was, among other things, a declaration against worldwide fallout. THE ATOM IN ENVIRONMENTAL STUDIES Although his experience with radioactivity has been brief, man probably already knows more about the effects of radiation than he knows about the effects of many other contaminants that alter his environment. Even so, he knows far less than he needs to know to make certain that atomic energy is wisely managed in the future.