Attachment 2-D CS 471.6 (11 Feb 53) Honorable Carl T. Durham House of Representatives Dear Mr. Durham: The Secretary of the Army has asked that the Joint Committee on Atomic Energy be informed of steps being taken by the Army in connection with exposure of troops at tests of atomic weapons. I am taking the liberty to furnish this information to you for any action you may care to take to inform other Members of the Committee. I am sure that you are familiar with the safety problem posed by the employment of atomic weapons in support of ground forces. For some time now the Army has been including troops in the atomic weapons tests at Nevada with a view to acquainting large numbers of troops with the problems associated with the use of these weapons, and at the same time developing doctrine in connection with tactical employment. On the first occasion of introducing troops to atomic explosions, we stationed them approximately eight miles away from the center of the explosion and at this distance found that the troops gained limited indoctrination from the maneuver. In order to improve on this indoctrination we moved the troops at later explosion to positions as close as 7,000 yards from the center of the explosion, conservatively placing them in trenches to be very sure that no injury to the troops would result. Here again we found that he had not yet reached the point where the atomic explosion itself had any significant effect, psychological or otherwise, on the ability of the troops to maneuver after the explosion. A detailed analysis of atomic weapons effects has led us to the belief that troops in deep foxholes will be safe from a 20 kiloton explosion at points as close as 1,5000 yards from ground zero, the point on the ground directly under the center of the explosion. Based on these considerations, we have prepared doctrine for the employment of atomic weapons which would lead commanders to risk their troops at distances as close as this to the explosion of the 280cm atomic projectile, assured of the reliability of such a delivery system and the accuracy with which we know we can deliver atomic artillery fire. Honorable Carl T. Durham Accordingly, we consider it of great importance that troops, in maneuvers in connection with atomic tests in Nevada, must be placed in foxholes at distances as close as 1,500 yards from ground zero in order to confirm the doctrine we have disseminated to our field forces. To accomplish this indoctrination. we are issuing to the maneuver commander at the next series of test, discretionary authority to station a small number of well informed volunteers in foxholes in positions as close as 1,500 yards to ground zero if meteorological and other conditions at the site will permit. Recognizing that yields of these test weapons are somewhat uncertain and conditions at the test site introduce other variables, this discretionary authority will include instructions that none of these selected volunteers shall be subjected to effects in excess of 8 lbs per square inch of pressure (measured at ground level), 10 roentgens is prompt, whole body radiation, or thermal radiation in excess of one calorie per square centimeter. In addition to these limitations, one selected volunteer shall receive more than 25 roentgens during the whole series of tests. We have been assured by experts that it is highly improbable that troops will suffer any injury under these conditions. For your information, the exposure criteria for the general troop participation will be somewhat more conservative than that indicated for the selected volunteers in view of the greater difficulty of handling larger bodies of troops (see attached criteria). L.L. LEMNITZER Lieutenant General, CS Deputy Chief of Staff for Plans and Research Encl: Criteria cc: LLD CRITERIA FOR POSITIONING OF TROOPS AT ATOMIC WEAPONS TESTS 1. The exposure of personnel will be limited to the following: a. Overpressure -- five (5) pounds per square inch. b. Nuclear radiation -- six (6) roentgens at any one test, of which no more than three(3) roentgens is prompt, whole body radiation. c. Thermal radiation -- one (1) calorie per square centimeter. 2. The following criteria will be observed as a basis for positioning troops at atomic tests: a. For tower shots -- Maximum Predicted Troops In Open Troops in Yield Trenches 1 to 5 KT 4,500 yds 3,500 yds 5 to 10 6,500 3,500 10 to 15 8,000 3,500 15 to 20 9,000 3,500 20 to 25 10,000 3,500 25 to 30 11,000 3,700 30 to 35 12,000 3,800 35 to 40 12,000 4,000 b. For 280cm gun delivered missiles -- add 1,000 yards to distances given in 2a, above. c. Aircraft delivered bombs -- (1) Add 3,000 yards to distances given in paragraph 2a. above (2) Permit no selected individual closer than 6,5000 yards. d. Troops positions must be located so that a gun or aircraft delivered weapon is delivered along aline in front of and parallel to the troop position.