The above descriptions are intended to help explain the complexity of the radiological conditions encountered in early surveys and later in the detailed efforts of the actual cleanup. But the story doesn't end here; post-test action contributed further to the heterogeneous mix of radionuclides and soil found on someislands. Post-Test Actions. Details of post-test activities are not available for all tests, but records reviewed for some tests present enough information to construct a hypothesis of the usual pattern of activity. Readings of the level of radioactivity following a test would be obtained with instruments in a low flying helicopter. When the level had fallen low enough for protected personnel to enter the area, recovery teams would go in to take additional readings, to evaluate scientific experiments and to recover specimens from the test area. In some cases, it was necessary to grade the roads to reduce exposure to re-entry crews. Following the Quince test on Yvonne, the contaminated soil was hurriedly pushed aside by bulldozer so preparations for the Fig test could start immediately. Documentation of this soil movement is better than for most of the tests. The following account of post-test actions illustrates the extreme case of soil disturbance. The Erie event on Yvonne produced heavy contamination. The behavior of the device was such that much debris remained in the GZ area. Also, Erie was heavily instrumented to evaluate weapons effects on missile structures and materials. Six arrays of test specimens were arranged west of the tower at 45° from horizontal and below the tower such that the specimens would impact west of ground zero. Specimens were recovered as far as 450 feet from GZ and generally from northwest through southwest and at depths of up to five feet. It is reported that earth was excavated up to six to eight feet deep and that 100,000 cubie yards of earth were moved in the recovery operations. The recovery procedure involved making 6-inch cuts with a "carry-all" and spreading the earth in 2-ineh layers. The earth was removed from the impact area and spread in a pile about 300 feet long and three swaths wide northwest of the GZ along the ocean side of the island. Not all specimens were recovered. The pile was later returned to the impact area and the area graded. One unsubstantiated but plausible story has been told about activities following the X-ray event on Island Janet. The story says that a Russian submarine was spotted at sea northwest of Janet in the days before and after the test. Fearing that the Russians might land a party on Janet to collect samples which could reveal useful information about the fuel used in the X-ray device, a bulldozer wassent into the area as soon as it was safe for the operator, and dirt was pushed around willy-nilly to mix the radionuclides into the soil. Other objects in the area were deliberately moved around so that test effects would not be readily discernible. This may be only a story, but the observed radiological conditions in the vicinity of the X-ray GZ would make more senseif the story were true. Caretaker Actions. Actions taken to place the proving ground in caretaker status are not well documented from the standpoint of the effect of these actions on the radiological conditions. Once photographs had been taken to document effects, and apparatus used in seientifie experiments had been retrieved, work crews dismantled the more valuable or delicate equipment and facilities and removed them to Elmer or Enewetak for storage, as long as they were not contaminated. For the most part, these actions would not complicate the radiological conditions. The notable exception was re~excavation of trenches to recover buried cables. This was not always done as is evidenced by the large amount of cabling found during the cleanup of 1977-79. 1.5 POST-TESTING PROGRAMS The last test of a nuclear device at Enewetak Atoll occurred in August 1958, but the Atoll continued to be used for various Defense Department programs from then up to the start of cleanup in May 1977. During the 1960's, Enewetak was the target and impact area for tests of Intercontinental Ballistic Missiles. Concurrently, laboratories involved in studies of marine biology continued their investigations, making Enewetak the most studied coral atoll in the world. (Helfrich, 1972.) Although these studies were not primarily concerned with radiological conditions, the basic understanding of atoll processes would be valuable in ongoing studies of radiation in the environment. In the early 1970's other programs were developed with Enewetak Atoll as the base. In the sections that follow, emphasis will be on the effects these programs had on cleanup ortheir contribution to the understanding of the complex radiological conditions encountered during cleanup. The historical sequence of events is not intended to be complete; instead, it will be limited to the background necessary to understand why and how certain conditions came about. Additional details may be obtained from sourceslisted in the bibliography. 15