MONTHLY STATUS AND PROGRESS REPORT Division of Biology and Medicine MONTH OF APRIL, 1952 Weapons Test Activities Fall-out Studies az: Dust and fall-out measurements are being made at and near the Nevada Teat Site within the 10 to 50 mile radius from ground zero for three of the tower detonations of the Tumbler-Snapper series. ‘The monitoring teams include 20 civilian personnel and 12 enlisted men from the Armed Forces. The objectives of the program are: 1. To measure the radioactivity per cubic meter in air for 2 hours following a detonation. 2. To determine approximate size distribution of particles in the air, 3. To chart the pattern of fall-out within this area by the use of gummed paper at approximately 100 collecting points. 4. To obtain an outline and measurement of radioactivity of particularly hot areas by means of survey teams, Greenhouse Report (a Analysis of the results of the biomedical experiments conducted in connection with Operation "Greenhouse" has been completed. Some of the important results may be muamarized as follows: 1. It appears that there is a relatively complete analogy between the injury produced by single doses of whole body radiation in animals and man——whether the source of radiation be a nuclear weapon or high voltage Keraysa used in laboratory experiments. DO ARCHIVES