DNA 6002F z:a 7Jj--: 10 ~· =- SHOT HOOD A Test of the PLUMBBOB Series 5 July 1957 United States Atmospheric Nuclear Weapons Tests Nuclear Test Personnel Review llll 1 4 1981 Prepared by the Defense Nuclear Agency as Executive Agency for the Department of Defense Destroy this report when it is no longerneeded. Do not return to sender. PLEASE NOTIFY THE DEFENSE NUCLEAR AGENCY, ATTN: STTI, WASHINGTON, D.C. 20305, IF YOUR ADDRESS IS INCORRECT, IF YOU WISH TO BE DELETED FROM THE DISTRIBUTION LIST, OR IF THE ADDRESSEE IS NO LONGER EMPLOYED BY YOUR ORGANIZATION. 0 N"' UNCLASSI FlED SECURITY CLASSIFICATION OF THIS PAGE (When Data Entered) READ INSTRUCTIONS REPORT DOCUMENTATION PAGE BEFORE COMPLETING FORM 1. REPORT NUMBER 3. RECIPIENT'S CATALOG NUMBER _r GOVT ACCESSION NO DNA 6002F 4. TITLE (and Subtitle) 5. TYPE OF REPORT & PERIOD COVERED SHOT HOOD Final Report A TEST OF THE PLUMBBOB SERIES 6. PERFORMING ORG. REPORT NUMBER JRB 2-816-03-423-00 7. AUTHOR(s) B. CONTRACT OR GRANT NUMBER(eJ Carl Maag, Martha Wilkinson, James Striegel, Burt Collins (Tech. Reps.) DNA 001-79-C-0473 :9. PERFORMING ORGANIZATION NAME AND ADDRESS 10. PROGRAM ELEMENT, PROJECT, TASK AREA 8: WORK UNIT NUMBERS JRB Associates, Inc. 8400 Westpark Drive Subtask U99QAXMK506-08 Mclean, Virqinia 22102 11. CONTROLLING OFFICE NAME AND ADDRESS 12. REPORT DATE Director 27 February 1981Defense Nuclear Agency 13. NUMBER OF PAGES Washington, D.C. 20305 114 14. MONITORING AGENCY NAME 8: ADORESS(If different from Control/Inti Office) 1S. SECURITY CLASS. (of this report) UNCLASSIFIED 1Sa. DECLASSI FICATIONIDOWNGRADING SCHEDULE N/A 16. DISTRIBUTION STATEMENT (of this Report) Approved for public release; distribution unlimited. 17•. DISTRIBUTION STATEMENT (of the abstract entered In Block 20, If different from Report) 18. SUPPLEMENTARY NOTES For sale by the National Technical Information Service, Springfield, VA 22161 This work sponsored by the Defense Nuclear Agency under RDT&E RMSS Code 8350079464 U99QAXMK50608 H2590D. 19. KEY WORDS (Continue on reverse side If necessary and Identify by block number) HOOD Nevada Test Site PLUMB BOB AFSWP Ionizing Radiation AFSWC Exercise Desert Rock Nuclear Weapons Tests Nevada Test Organization Atmospneric Nuclear Tests 20. ABSTRACT (C"mrtfaue ""'rever.. slditl if ~aary ami ldenllfy by block number) This report describes the activities of DoD personnel, both military and civilian, in Shot HOOD, the 6th nuclear test in the PLUMBBOB atmospheric weapons testing series. The test was conducted on 5 July 1957 and involved participants from Exercise Desert Rock VII and VIII, AFSWP, AFSWC, and AEC test groups. This volume also describes the radiological safety criteria and procedures in effect at Shot HOOD. FORM 1~ EDITION OF ' NOV 65 IS OBSOLETE DD \JAN 73 ..,~ UNCLASSIFIED SECURITY CLASSIFICATION OF THIS PAGE (When Data Entered) UNCLASSIFIED SECURITY CLASSIFICATION OF THIS PAGE(When Data Entered) 18. SUPPLEMENTARY NOTES (Cont.) ~ f The Defense Nuclear Agency Action Officer, Major H. L. Reese, under whom this work was done, wishes to acknowledge the research and editing contribution of numerous reviewers in the Military Services and other organizations in addition to those writers listed in block 7. UNCLASSIFIED SECURITY CLASSIFICATION OF THIS PAGE(When Data Entered) PREFACE Between 1945 and 1962, the United States Atomic Energy Commission (AEC) conducted approximately 235 atmospheric nuclear weapons tests at sites in the southwestern U.S. and in the Pacific and Atlantic Oceans. In all, an estimated 220,000 Department of Defense (DOD) participants, both military and civilian, were present at the tests. Approximately 90,000 of these participants were present at the nuclear weapons tests conducted at the Nevada Test Site (NTS)* north of Las Vegas, Nevada. In 1977, 15 years after the last above-ground weapons test, the Center for Disease Control, U.S. Department of Health, Education, and Welfare (now the Center for Disease Control, U.S. Department of Health and Human Services), noted a possible leukemia cluster among a small group of soldiers present at Shot SMOKY, the 15th test of Operation PLUMBBOB, the series of nuclear weapons tests conducted in 1957. Following that initial report by the Center for Disease Control, the Veterans Administration received a number of claims for medical benefits from former military personnel who believe their health may have been affected by their participation in the nuclear weapons tests. In late 1977, DOD began a study to provide data to both the Center for Disease Control and the Veterans Administration on potential exposures to ionizing radiation among its military and civilian participants in the atmospheric nuclear weapons tests 15 to 30 years earlier. The DOD study was organized as the Nuclear Test Personnel Review: • To identify and locate DOD personnel who had taken part in the atmospheric nuclear weapons tests *Formerly called Nevada Proving Ground, the name of the test range was changed to the Nevada Test Site following the completion of Operation TEAPOT in 1955. 1 • To determine the extent of the participants' exposure to ionizing radiation • To provide public disclosure of information concerning participation by DOD personnel in the atmospheric nuclear weapons tests. This report on Shot HOOD is based on the historical record of military and technical documents associated with each of the nuclear weapons test events. The reports of the Nuclear Test Personnel Review provide a public record of the activities and associated potential for radiation exposure of DOD personnel, for use in ongoing public health research and policy analysis. Many of the documents pertaining specifically to DOD involvement during Shot HOOD were found in the Defense Nuclear Agency Technical Library, the National Archives, the Department of Energy Nevada Operations Office, and the Los Alamos Scientific Laboratory (LASL). The most significant sources of information used in the development of this report include: • Final Report of Operations for Exercise Desert Rock VII and VIII • Operational Order Seven for Exercise Desert Rock VII and VIII • Operational Summary for the Armed Forces Special Weapons Project (AFSWP) • Air Mission Summary Report for Shot HOOD • AFSWC Final Report of the 4950th Test Group (Nuclear) • AFSWC Operation Plan 1-57 • Onsite Radiological Safety Report prepared for the NTO by REECo • Report of the Test Manager 2 • Report of the Test Director • Personal Interviews. Frequently, the surviving historical documentation of activities conducted at Shot HOOD addresses test specifications and technical information, rather than the personnel data critical to the study undertaken by the Defense Nuclear Agency. Moreover, instances have arisen in which available historical documentation has revealed inconsistencies in vital factual data, such as the number of DOD participants in a certain project at a given shot or their locations and assignments at a given time. These incon sistencies in data usually occur between two or more documents, but occasionally appear within the same document. Efforts have been made to resolve these data inconsistencies wherever possible, or to otherwise bring them to the attention of the reader. ORGANIZATION AND CONTENT OF THE PLUMBBOB SERIES REPORTS This volume details participation by DOD personnel in Shot HOOD, the sixth detonation of the Operation PLUMBBOB nuclear weapons testing series. Seven other publications address DOD activities during the PLUMBBOB Series: • Series Volume: Operation PLUMBBOB Atmospheric Nuclear Weapons Tests, 1957 • Multi-shot Volume: Shots BOLTZMANN to WILSON, the First Four Tests of the PLUMBBOB Series • Shot Volume: Shot PRISCILLA, a Test of the PLUMBBOB Series • Multi-shot Volume: Shots DIABLO to FRANKLIN PRIME, the Mid-series PLUMBBOB Tests • Shot Volume: Shot SMOKY, a Test of the PLUMBBOB Series • Shot Volume: Shot GALILEO, a Test of the PLUMBBOB Series 3 • Multi-shot Volume: Shots WHEELER to MORGAN, the Final PLUMBBOB Tests. The volumes addressing the test events of Operation PLUMBBOB have been designed for use with one another and have been organized to avoid repetition of information between volumes. The Series volume contains information which applies to those dimensions of Operation PLUMBBOB which transcend specific events, such as historical background, organizational relationships, and radi ation-safety procedures. In addition. the Series volume contains a bibliography of works consulted in the preparation of all five Operation PLUMBBOB reports. The single-shot volumes describe DOD participation in Shots PRISCILLA, SMOKY, and GALILEO. These volumes have been bound separately because they included substantial numbers of Desert Rock participants. Each multi-shot volume combines shot-specific descriptions for several nuclear events, each involving smaller numbers of DOD personnel. The shot and multi-shot volumes contain bibliographies only of the sources referenced in each text. Descriptions of activities concerning any particular shot in the PLUMBBOB Series, whether the shot is addressed in a single-shot volume or in a multi-shot volume, should be supplemented by the general organizational, and radiation-safety information contained in the PLUMBBOB Series volume. One other important source of information relevant to this report includes the ''Reference Manual: Background Materials for the CONUS Volumes,'' which summarizes information on the physical processes and characteristics of a nuclear detonation, radiation physics, radiation health concepts, exposure criteria, and measurement techniques, as well as listing acronyms and a glossary of terms used in the Nuclear Test Personnel Review reports addressing test events in the continental U.S. 4 Chapter 1 of this volume describes the physical setting of the HOOD detonation and introduces the Desert Rock maneuvers and those Nevada Test Organization (NTO) diagnostic and scientific activities in which DOD personnel participated. Chapter 2 describes the Exercise Desert Rock VII and VIII military projects conducted at Shot HOOD, while chapter 3 describes various training activities, scientific experiments, and support missions conducted at HOOD by the NTO in which DOD personnel took part. These chapters provide information about the number of DOD people involved in specific projects fielded at Shot HOOD, the time spent by project personnel in the test area, and their positions relative to the point of detonation and areas of radioactivity before, during, and after the test. Chapter 4 of this volume describes the radiological environment and safety procedures pertinent to Shot HOOD, including isointensity contour maps illustrating the radiological contamination around ground zero following the detonation, and available shot-specific exposure data for individuals. Details of the overall radiological protection program at Operation PLUMBBOB are provided in the Series volume. 5 TABLE OF CONTENTS _Chapter PREFACE. . . . . . . . . . . . . . . . . . . . . LIST OF ILLUSTRATIONS . . • • • • • • • • • • . . . LIST OF TABLES • • • • • . • • • • • • . . . LIST OF ABBREVIATIONS AND ACRONYMS . . . SHOT HOOD SYNOPSIS . . . 1 INTRODUCTION 1.1 Setting and Char~cteristics of the HOOD Detonation .••••••••• 1.2 Department of Defense Scientific, Operational Training, and Support Activities at Shot HOOD ..•.•• 1.3 Exercise Desert Rock Activities at Shot HOOD. . • . • • . . . • • • • . . 2 EXERCISE DESERT ROCK VII AND VIII OPERATIONSAT SHOT HOOD 2.1 Troop Observer Indoctrination Projectsat Shot HOOD • • • • • • . • • • • . • . . • 2.2 Troop Test Project at Shot HOOD. . . . . . • . . 2.3 Radiological Training Project at Shot HOOD ..... 2.4 Technical Service Projects at Shot HOOD. . • .. 3 NEVADA TEST ORGANIZATION OPERATIONS AT SHOT HOOD 3.1 Field Command Weapons Effects Test GroupProjects at Shot HOOD •.•..•...•....•. 3.2 Department of Defense Participation inLASL and UCRL Test Group Projects at Shot HOOD ••• 3.3 Department of Defense Participation inCivil Effects Test Group Projects at Shot HOOD • 3.4 Department of Defense Operational Tr~ining Projects at Shot HOOD •..•..•.. 3.5 Air Force Special Weapons Center Activities at Shot HOOD. . . •. 3.5.1 Cloud Sampling .•.•••.. 3.5.2 Courier Missions .•••... 3.5.3 Cloud Tracking ••• 3.5.4 Cloud Penetration •.•••• 6 Page 1 7 8 9 10 11 12 15 19 22 24264445 48 48 64 65 67 69 7071 7272 TABLE OF CONTENTS (Continued) Chapter 3.5.5 Security Sweep Missions • . . . . . 72 3.5.6 Terrain Survey Missions • 73 4 RADIATION PROTECTION AT SHOT HOOD 74 4.1 Film-badge Readings for Participants in Project 52.1, Marine Brigade Exercise, at Shot HOOD •• 74 4.2 Nevada Test Organization Radiation Protection Activities at Shot HOOD ••• 79 REFERENCES 88 LIST OF ILLUSTRATIONS Figure 1-1 Location of Shot HOOD in the Nevada Test Site, in Relation to Other Shots in the PLUMBBOB Series • 13 1-2 View of Shot HOOD Detonation. 16 2-1 Desert Rock Project 52.1, Troop Movement Plan 25 2-2 Marines Return to Camp Desert Rock after Shot DIABLO Failed to Detonate Because of Electrical Problems ••• 33 2-3 Aerial View of Trenches to be Occupied by Fourth Marine Corps Atomic Exercise Brigade During Shot HOOD • 36 2-4 Before the HOOD Detonation, Observers Covered Their Eyes and Turned Away from the Shot Site as a Loudspeaker Announced the Countdown • • • . • 38 2-5 The Marine Corps Ontos Vehicle is Shown with the Shot HOOD Cloud in the Background • 40 2-6 Marine Corps Helicopters Landing to Recover Men and Supplies After the Detonation of HOOD • • • • . • • . . 41 2-7 Marines Boarding Helicopter After Shot HOOD • • 42 4-1 Distribution of Total Film Badge Readings, Project 52.1, Shot HOOD • . • • • . • • • • • • • • • • • • • • . . • 76 7' LIST OF ILLUSTRATIONS (Continued) 4-2 Distribution of Total Film Badge Readings, Project 52.1, Participants with Three Film Badges (Monitors) ••••• 78 4-3 Initial Survey for Shot HOOD, 5 July 1957, Mid-time 0536 • • • • • • • • . • • • • • 81 4-4 Resurvey for Shot HOOD, 5 July 1957, Mid-time 1052. 82 4-5 Resurvey for Shot HOOD, 6 July 1957, Mid-time 0613. 4-6 Resurvey for Shot HOOD, 7 July 1957, Mid-time 0818. 84 4-7 Resurvey for Shot HOOD, 8 July 1957, Mid-time 0658. 85 LIST OF TABLES Table 2-1 Exercise Desert Rock VII and VIII Projects, Shot HOOD • • • • • • • • • • • • • • • • • 23 3-1 Field Command Weapons Effects Test Group Projects, Shot HOOD • • • • • . • • • • • • • • • • • • • • 49 3-2 LASL, UCRL, and CETG Projects with DOD Personnel Involvement, Shot HOOD. . . . . . . . . . . . . . . 65 3-3 DOD Operational Training Projects, Shot HOOD. . . . 67 3-4 AFSWC Air Mission Support, Shot HOOD. . . . . . . . 70 8 The following AEC AFB AFSWC AFSWP BJY CETG DOD FCDA LASL NTO NTS REECo R/h UCR.L USAF UTM LIST OF ABBREVIATIONS AND ACRONYMS abbreviations and acronyms are used in this volume: Atomic Energy Commission Air Force Base Air Force Special Weapons Center Armed Forces Special Weapons Project Buster-Jangle "Y" Civil Effects Test Group Department of Defense Federal Civil Defense Administration Los Alamos Scientific Laboratory Nevada Test Organization Nevada Test Site Reynolds Electrical and Engineering Company Roentgen-per-hour University of California Radiation Laboratory United States Air Force Universal Transverse Mercator 9 SHOT HOOD SYNOPSIS AEC Objective: DOD Objective: Weather at Shot Time: Radiation Exposure History: AEC Participants: DOD Participants: To evaluate the nuclear yield and the blast, thermal and radiation phenomena produced by AEC TEST SERIES: PLUMBBOB DOD EXERCISES: Desert Rock VII and VIII DATE/TIME: 0440 Hours, 5 July 1057 YIELD: 74 KT HEIGHT OF BURST: 1,500 feet (balloon shot) this nuclear device. (1) To assess the effects of nuclear detonations on civilian populations and to evaluate Civil Defense emergency preparedness plans. (2) To evaluate the utility of the device for military applications, and to investigate additional specifications for further nuclear weapons development. Temperature was 21°C; relative humidity at 19 percent, pressure at 76 millibar. The wind was calm at surface level. At 35,000 feet, the wind was from the southwest about 20 knots and at the top of the cloud at about 30 knots. Heavy onsite fallout, greater than 0.1 R/h, was confined to a circular area 2,000 meters from ground zero. Light to moderate fallout, between 0.01 and 0.1 R/h also covered a roughly circular region, extending 2,500 meters from ground zero. Test Manager's Organization, LASL, UCRL Exercise Desert Rock Troops, AFSWC, AFSWP, Federal Civil Defense Administration. 10 CHAPTER 1 INTRODUCTION Shot HOOD was a test of a 74-kiloton nuclear device con ducted at 0440 hours Pacific Daylight Time on 5 July 1957 at the Nevada Test Site (NTS), the U.S. Atomic Energy Commission conti nental nuclear test area, located northwest of Las Vegas. HOOD was the sixth nuclear test of Operation PLUMBBOB, a series of 24 nuclear weapons tests and six safety experiments performed in Nevada between 24 April and 7 October 1957. The HOOD nuclear device was sponsored, designed, and built for the Atomic Energy Commission (AEC) by the University of California Radiation Laboratory (UCRL). The primary objective of the HOOD event was to evaluate the nuclear yield and the blast, thermal, and radiation phenomena produced by this nuclear device. To fulfill this objective, UCRL and the Los Alamos Scientific Laboratory (LASL) fielded scientific and diagnostic experiments to study the characteristics of the detonation. Other scientific experiments were performed by the Armed Forces Special Weapons Project (AFSWP) of the Department of Defense to determine the effects of the detonation on military equipment, materiel, structures, and ordnance. A number of other activities related to the conditions and phenomena produced by a nuclear detonation were also conducted during the HOOD event. These included the Desert Rock exercises, operational training projects, and Federal Civil Defense Administration (FCDA) projects. As part of Exercise Desert Rock VII and VIII, the armed services fielded six projects to evaluate military equipment and tactics. In one project, the Marine Corps conducted a troop maneuver in the test area immediately after the detonation. This 11 about 2,100 to 2,200 Marines, included maneuver, which involved helicopter airlifts of assault troops, tactical air support, and air resupply. This operation was the largest single military activity in the PLUMBBOB Series. In addition to the six Desert Rock projects, the Department of Defense also conducted four operational training projects at HOOD. The Federal Civil Defense Administration conducted another ten projects to assess the effects of nuclear detonations on civilian populations and to evaluate Civil Defense emergency preparedness plans. Department of Defense participation in these projects was limited. Altogether, the various activities at Shot HOOD were grouped into 51 projects. As described in subsequent sections of this chapter, DOD personnel were involved in 34 of these projects. 1.1 SETTING AND CHARACTERISTICS OF THE HOOD DETONATION The nuclear device tested at Shot HOOD was suspended from a balloon 1,500 feet above Area 9 at UTM coordinates 852100, * a location in the northeastern part of Yucca Flat. Figure 1-1 shows the location of the HOOD detonation in relation to other shots in the PLUMBBOB Series. Shot HOOD was originally scheduled for 27 June 1957. When Shot DIABLO, which was planned for 25 June 1957, was delayed by technical difficulties, HOOD was rescheduled for 3 July 1957. Additional difficulties forced a further delay in the HOOD detonation to 5 July. *Universal Transverse Mercator (UTM) coordinates are used in this report. The first three digits refer to a point on an east-west axis, and the second three refer to a point on a north-south axis. The point so designated is the southwest corner of an area 100 meters square. 12 r --------,---, ~ I 1 I RAINIER ~ I I I I® p---,I SMOKY I L 12 ___ .- _ _ ~..J,.....,...--~~--- JOHN DIABLO WHITNEY SHASTA KEPLER -------1.-.....® ----+--® ---------+1---® :'f-. ---_______...___® ® 10 ~---=--4 \ tO\ ,~~-~,----' 9-,--_l_ .......,I ® I \ LASSEN WILSON / HOOD OWENS WHEELER CHARLESTON MORGAN BOLTZMANN GALlLEO __________...______,® I~ /STOKES \DOPPLER FRANKLIN PRIME LA PLACE / N.EWTON ~ FRANKLIN ~'-----~ FIZEAU I I I I I ~~:a___1_!J P I \.JI I I I L6____ _ I ------1 I II I I PRISCILLA a;-I Frenchman I lake / 5 I ---· ___ ] Camp Mercury 0 10 ~!i. Camp De.ert I Rock _-) Kilometers Figure 1-1: LOCATION OF SHOT HOOD IN THE NEVADA TEST SITE, IN RELATION TO OTHER SHOTS IN THE PLUMBBOB SERIES 13 At 2230 hours on 4 July 1957, Project 52.1 participants in the Marine Brigade Exercise moved to the HOOD observation trenches, 5,000 meters* from ground zero. These troops includedmembers of the First Marine Division of the Fourth Marine CorpsProvisional Atomic Exercise Brigade. The Third Light SupportCompany and Desert Rock transport units, which had trucked theMarines to the trench areas, retired to the parking area near theControl Point at Yucca Pass. Other transportation units were situated at the vehicle assembly area near the Marine command post. Three helicopter squadrons of Marine Air Group 36 and elements of Company G of the Second Battalion, Fifth Marines, were located at Loading Zone Number One at Yucca Pass. The airand ground elements of Marine Air Group 15, which was to provideair cover for Project 52.1, operated from the Marine CorpsAuxiliary Air Station at Mojave, California. An additional 312 military observers were situated either inthe main trenches with the Marines of Project 52.1, or in theobserver area located approximately ten kilometers southeast ofground zero. Diagnostic instruments and project equipment placedearlier by test group personnel were arranged around the HOODshot area. In the air, aircraft positioned themselves for thedetonation. The HOOD device was detonated at 0440 hours Pacific Daylight Time on 5 July 1957. At the time of the detonation, the wind wascalm at surface level. At 35,000 feet, + the wind blew from thesouthwest at 25 knots and at 43 knots at 50,000 feet. The top of *Throughout this report, surface distances are given in metric units. The metric conversion factors include: 1 meter = 3.28 feet; 1 meter= 1.09 yards; and 1 mile= 1.61 kilometers. Altitudes and other vertical distances are given in feet. +Altitudes are measured from mean sea level, unless otherwisenoted. 14 the cloud reached an altitude of 48,000 feet (20).* Figure 1-2 shows the HOOD detonation. Shot HOOD yielded 74 kilotons of explosive energy. The residual radiation consisted primarily of neutron-induced activity around g~ound zero. Offsite fallout from HOOD was minor and occurred in an area north-northeast of the NTS (20). After the detonation, Project 52.1 personnel began a coor dinated air-ground maneuver against attack objectives. Marine fighters from the Marine Corps Auxiliary Air Station at Mojave, California, provided air support. This exercise was completed by 1100, at which time the Marines viewed the equipment display area and then returned to Camp Desert Rock. When the Test Manager declared that conditions were safe, subject to radiological exposure criteria, test group participants began recovering scientific and technical instruments from the area around ground zero. Meanwhile, AFSWC pilots conducted cloud-sampling and cloud-tracking missions. 1.2 DEPARTMENT OF DEFENSE SCIENTIFIC, OPERATIONAL TRAINING, AND SUPPORT ACTIVITIES AT SHOT HOOD The Nevada Test Organization (NTO) was established for planning, coordinating, and conducting atmospheric nuclear weapons tests during Oper!ition PLUMBBOB. All activities of the NTO were under the overall control of an AEC-appointed Test Manager, assisted by the Test Director. The NTO was comprised of personnel from the Atomic Energy Commission, the Department of Defense, and the Federal Civil Defense Administration, and included representatives from the AFSWP Weapons Effects Test Group (WBTG), *All sources cited in the text are listed alphabetically and numbered in the Reference List, appended to this volume. The number given in the citation in the text is the number of the source document in the Reference List. 15 2 0 ..... <( 2 0 ..... w c c 0 0 :I: ..... 0 :I: rJ) u.. 0 3: w > N I ..... Q) ... :l C'l u.. the LASL Test Group, the UCRL Test Group, and the FCDA Civil Effects Test Group (CETG). These test groups conducted 41 military effects and diagnostic projects at Shot HOOD. More than half of these projects included DOD participation. Four other projects were performed by Air Force and Marine personnel as part of the DOD operational training program. Personnel from DOD agencies and all four armed services participated in the experiments conducted by the four test groups, whose activities were coordinated by the Test Director. The largest such DOD involvement was in the 18 military effects projects of the Weapons Effects Test Group. DOD personnel also assisted in eight of the projects conducted by the other test groups, but DOD participation in these eight projects was limited. Participants in the scientific and diagnostic experiments placed data-collection instruments around the point of detonation in the days and weeks preceding the scheduled event. After the detonation, when the Test Manager had determined that the radiological environment in the test area would permit limited access, participants recovered instruments and equipment. About 250 people took part in the projects conducted by the WETG, and less than 15 assisted in those conducted by LASL, UCRL, and CETG. The operational training projects, which involved about 14 Air Force personnel and 19 Marines, were designed to test service tactics and equipment and to train military personnel in the effects of a nuclear detonation. Three of these projects required aircrews to fly their aircraft in the vicinity of the Nevada Test Site at the time of the detonation to observe or photograph the fireball and the rise of the resulting nuclear cloud. The fourth project evaluated the accuracy of bomb damage assessment equipment inside an aircraft. These projects, like those of the test groups, were approved and coordinated by the Test Director. 17 In addition to those people involved in experiments ~nd tr~ining, staff and support personnel, including Air Force Special Weapons Center (AFSWC) personnel flying special missions for the Test Manager, provided necessary services to other participants at the test site. A total of about 500 DOD people were involved in these activities. One important support function during Shot HOOD was provided by the Air Force Special Weapons Center (AFSWC), based at Kirtland Air Force Base (AFB), New Mexico. This group, which included about 200 air and ground personnel, provided air support to the Test Manager and to three test group projects. During Operation PLUMBBOB, AFSWC was comprised of units from the 4950th Test Group (Nuclear), including the 4926th Test Squadron (Sampling) ann the 4935th Air Base Squadron. Support was also provided by the 4900th Air Base Group. A total of 493 airmen and 23 officers of the 4950th were stationed at Indian Springs AFB (17). These units operated from Indian Springs Air Force Base, 38 kilometers southeast of the NTS. Support was also provided by the 4900th Air Base Group at Kirtland AFB. For HOOD, AFSWC performed several missions, including aircraft control, security sweeps, cloud-sampling, cloud-tracking and penetration, a radio relay, terrain surveys, and courier services. To minimize exposure to ionizing radiation, radiation protection procedures were established by the Nevada Test Organization. Participants were to receive no more then three roentgens of whole-body gamma radiation for any 13-week period and five roentgens of whole-body gamma radiation annually. To ensure these criteria were followed, access to contaminated areas was rigidly controlled, and project personnel recovering test instruments from highly contaminated areas were accompanied by radiological safety monitors. The monitors, who continuously checked the radiation intensity in the recovery area, had the authority to order a halt to recovery operations if intensities were too 18 great or the length of time in the area were too long. Project personnel were issued film badges to wear at all times when in the test area. These film badges were collected, developed, and evaluated at regular intervals. Any individuRl whose accumulated exposure exceeded or would be expected to exceed the established limits was barred from further participation in project activities in the test area. Although not implemented during PLUMBBOB, emergency evacuation procedures were prepared for all test events (46). With one exception, the radiation protection procedures for the Air Force Special Weapons Center aircrew and ground-crew personnel were the same as those established for the NTO. As the single exception, the Test Manager authorized cloud sampler pilots to receive up to a total of 7.5 roentgens of gamma radiation annually. Complete decontamination, including showers and changes of clothing, was required of all aircrew members following each project mission, regardless of the exposure received on the flight. Aircraft were either decontaminated by washing or were isolated until radiation intensities had decayed to predetermined levels. This report on Shot HOOD documents the activities of these DOD personnel before, during, and after the detonation on 5 July 1957. These descriptions focus on the potential for exposure to ionizing radiation during the performance of assigned duties. 1.3 EXERCISE DESERT ROCK ACTIVITIES AT SHOT HOOD Over 3,000 DOD personnel participated in the eight projects at Shot HOOD of Exercise Desert Rock VII and VIII, the Army testing and training program conducted during Operation PLUMBBOB. These projects included two troop observer and indoctrination projects, one troop test, two radiological training projects, and three technical service projects. 19 The largest group of participants was the 2,100 Marines of the Fourth Marine Corps Provisional Atomic Exercise Brigade who performed the Marine Brigade Exercise. This project tested a task force assault on an objective in the vicinity of a nuclear detonation. Another 970 individuals took part in the other seven Exercise Desert Rock projects. These projects involved exposing military equipment to a detonation to evaluate the damage sustained, and testing military equipment and techniques for detecting nuclear bursts and fallout, and training military personnel. In addition to the Desert Rock exercise troops, about 2,000 support troops from various Army units maintained and operated Camp Desert Rock, providing transportation, communications, engineering, administrative, and security services. Of these Desert Rock Stlpport troops, some worked in the forward area of the Nevada Test Site to construct observer positions, lay communication lines, provide transportation and security, and assist in preparing for the Desert Rock projects. Soldiers from the 50th Chemical Platoon served as radiation-safety monitors for Desert Rock project personnel during nuclear test events. Radiation protection procedures at Exercise Desert Rock, as well as those of the Nevada Test Organization, are detailed in the PLUMBBOB Series volume. The procedures were designed to minimize potential exposure to ionizing radiation while allowing participants to accomplish their project objectives. Camp Desert Rock support personnel and exercise participants were limited to no more than five roentgens of whole-body gamma radiation during any six-month period. The radiation protection procedures of Exercise Desert Rock included provisions for (28): • Maintaining minimum safe distances from n11clear detonations 20 • Enforcing protective procedures for personnel observing the detonation • Controlling access to contaminated areas • Monitoring individuals working in contaminated areas • Film-badging Desert Rock personnel and monitoring the cumulative exposure of Desert Rock personnel • Decontaminating all equipment and personnel leaving the test area after the detonation. Members of the Fourth Marine Corps Provisional Atomic Exercise Brigade witnessed the detonation from trenches 4,570 meters southwest of ground zero. Heavy onsite fallout, greater than 0.1 R/h, was confined to a circular area 2,000 meters from ground zero. Light to moderate fallout, between 0.01 and 0.1 R/h also covered a roughly circular region, extending 2,500 meters from ground zero. Marines traveled as close to ground zero as the 5.0 R/h area, probably about 1,000 meters from ground zero. They remained in that area about ten minutes. This report documents the activities of the Desert Rock troops and other DOD personnel who participated in Shot HOOD. The activities of Desert Rock and NTO support personnel are detailed in the PLUMBBOB Series volume. 21 CHAPTER 2 EXERCISE DESERT ROCK VII AND VIII OPERATIONS AT SHOT HOOD Department of Defense personnel participated in six Exercise Desert Rock VII and VIII projects at Shot HOOD. The principalconcern throughout this chapter is with the Desert Rock activities that may have exposed participants to ionizing radiation before, during, and after the detonation. In all, about 3,000 individuals took part in the Desert Rock exercises atHOOD. Of these, approximately 2,100 to 2,200 participated in asingle project, the Marine Brigade Exercise. This chapter focuses on the troops assigned to Exercise Desert Rock VII and VIII to participate in HOOD. These individuals took part in one of four programs: the Troop Observer Indoctrination Program, the Troop Test Program, the Radiological Training Program, or the Technical Service Program. The Troop Observer Indoctrination Program was designed to train armed services personnel in the effects of a nuclear detonation.The Troop Test Program was designed to test military tactics anddoctrine, and to train command staff personnel in planning andconducting combat operations under the conditions anticipated fora nuclear battlefield. The Radiological Training Programprovided practice in the application of radiological protectionprocedures under conditions similar to those anticipated for anuclear battlefield. The Technical Service Program tested the effects of nuclear weapons on ordnance materiel, fortifications, structures, and equipment, as well as testing techniques for detecting nuclear detonations. Table 2-1 displays the Desert Rock programs and their subordinate projects conducted at Shot HOOD, and includes the numberof DOD personnel who took part in each. 22 Table 2-1: EXERCISE DESERT ROCK VII AND VIII PROJECTS, SHOT HOOD Program Type Project Troop Observer 50.2 Indoctrination 53.3 Troop Test 52.1 Radiological Training 53.4 Technical Service 50.3 50.7 50.8 Title Troop Observers Aircrew Observers Marine Brigade Exercise Radiological Defense Training Sixth Army Chemical, Biological, and Radiological Defense Training Evaluation of Medium Range Detonation-detection and Cloud Tracking Systems Test of Ordnance Material Detection of Atomic Burst and Radioactive Fallout Estimated Number of DOD Personnel 312 5 2,1002,200 36 24 25 10 557 Participants Army; Navy; United Kingdom Military Personnel Air Force Fourth Marine Corps Provisional Atomic Exercise Brigade Radiological Defense School, Lowery AFB, Denver, Colorado Sixth Army Army Signal Research and Development Laboratories Ballistic Research Laboratories; Continental Army Command; Detroit Arsenal Army Artillery and Guided Missile School; Chemical Corps; Air Defense Board; Artillery Board; Air Weather Service 23 2.1 TROOP OBSERVER INDOCTRINATION PROJECTS AT SHOT HOOD Two troop observer indoctrination projects were conducted at Shot HOOD: Project 50.2, Troop Observers and Project 51.3, Aircrew Observers. Project 50.2 engaged 312 observers: 308 from the Army, one from the Navy, two from the military of the United Kingdom, and one civilian whose agency is unknown (28). Project 53.3 included five people from the Air Force. The observers arrived at Camp Desert Rock about three days before the scheduled detonation of Shot HOOD. Two days before the shot, the observers received an eight-hour preshot orientation course. In the morning of the day before the shot, the observers were briefed on observation procedures and, that afternoon, were escorted on a tour of the NTS (28). On shot-day, the observers viewed the detonation either from the main trenches where the Marines of Project 52.1 were situated, or from an observer area located 10 kilometers southwest of ground zero (28). From one to three hours after the detonation, they inspected the equipment in the Project 52.1 display area, located between 240 meters and 2,170 meters from ground zero. Figure 2-1 indicates the locations of the observer and the equipment display areas. Available documentation is unclear as to whether Project 52.2, the Marine observer project, also occurred at Shot HOOD. The Army's Final Report of Operations states that Project 52.2 took place at HOOD. The same report, however, does not list Project 52.2 in its table of participants of Exercise Desert Rock events. The HOOD Operation Order also does not mention Project 52.2 (24). Film-badge data from Project 52.1 does list 44 Marine observers at Shot HOOD, and these men, most of whom were officers, may have actually participated in Project 52.1. 24 Marine Equipment Display Area Landing N Zone Pink 0GZ Objective AL~ Loading Zone . ~-U-·-. Two \' Landmg Zone Bl~e\ -·.:::j ( \ ,Q v-·-·-·-· Trench~ Objective sv Command =~~a Observer Area , ' Area Vehicled Assembly \i Area tl tl tl Parking Area Loading Zone One (Yucca Pass) To Camps Desert Rock and Mercury Legend: Helicopter Approach Helicopter Troop Lift Kilometers 0 5 Figure 2-1: DESERT ROCK PROJECT 52.1, TROOP MOVEMENT PLAN 25 The Army's Final Report of Operations lists the particip~tion of 299 Camp Desert Rock support troops at Shot HOOD (28). The manner of their involvement is unknown, although they probably observed the shot from News Nob, near the Control Point. 2.2 TROOP TEST PROJ8CT AT SHOT HOOD The only troop test conducted at Shot HOOD was Project 52.1, the Marine Brigade Exercise. The largest exercise ever performed at the NTS, this project engaged 2,100 to 2,200 members of the Fourth Marine Corps Provisional Atomic Exercise Brigade. Because the Marine Corps After Action Summary Report for Project 52.1 cannot be found, this estimate was derived by a series of calculations. In order to determine the participating units, Marine Corps researchers studied shots with similar activities, such as that of the Third Marine Corps Provisional ~tomic Exercise Brigade at Shot BEE, Operation TEAPOT. This study yielded a list of those units that probably took part in the Marine Brigade Exercise at HOOD. A search through the unit diaries for thes2 units revealed that they had been present at the shot. In addition, those diaries indicated the men who had been temporarily assigned to Camp Desert Rock to take part in HOOD. The unit diaries were cross-checked against muster rolls for the units and against the listing of individuals who had been issued film badges for the time period encompassing the July 5 detonation of Shot HOOD (25). Researchers concluded that, in addition to the participating Marines, about 300 members of the Camp Desert Rock support units, most of whom were drivers from Transportation Corps units which convoyed the Marines to and from the forward area, were onsite with the project participants. The principal participating units were from the First Marine Division, Camp Pendleton, California, and the Third Marine Air Wing from the Marine Corps Air Station, Santa Ana, California. 26 The table on the next page gives the subunits of the Fourth Marine Corps Provisional Atomic Exercise Brigade, which participated in Project 52.1 at the Nevada Test Site. Little documentation exists for Project 52.1 at Shot HOOD. An extensive search of the following offices and repositories yielded limited information on project activities: • Commandant of the Marine Corps, Washington, D.C. • Marine Corps Historical Center, Washington, D.C. • Operations Section, Camp Lejeune, North Carolina • Operations Section, Camp Pendleton, California • Defense Documentation Center, Alexandria, Virginia • Defense Nuclear Agency Technical Library, Alexandria, Virginia • Federal Records Center, Laguna, California • Federal Records Center, Mechanicsburg, Pennsylvania • Federal Records Center, San Bruno, California • Marine Nuclear Test Personnel Review, Washington, D.C. • Fleet Marine Force Pacific, Honolulu, Hawaii • Fleet Marine Force Atlantic, Norfolk, Virginia • Navy War College, Newport, Rhode Island • Federal Records Center, East Point, Georgia • Technical Information Library, Department of Energy, Oak Ridge, Tennessee • National Personnel Records Center, St. Louis, ~issouri • Chief of Naval Operations, Washington, D.C. • Federal Records Center, Kansas City, ~issouri. 27 Participating Unit First Marine Division Headquarters Company, Headquarters Battalion Support Company, 1st Pioneer Battalion Company A, 3rd Amphibian Tractor Battalion Company A, 1st Anti-tank Battalion 1st Hospital Company, 1st Medical Battalion Company B, 1st Motor Transport Division Company C, 3rd Amphibian Tractor Battalion Company D, 1st Medical Battalion Company E, 2nd Battalion, 5th Marine Regiment Company F, 2nd Battalion, 5th Marine Regiment Company G, 2nd Battalion, 5th Marine Regiment Company H, 2nd Battalion, 5th Marine Regiment Headquarters and Service Company, 2nd Battalion, 5th Marine Regiment Headquarters and Service Company, 1st Service Regiment, 1st Marine Division 1st Light Support Company, 1st Service Battalion, 1st Marine Division 3rd Light Support Company, 1st Service Battalion, 1st Marine Division 3rd Amphibian Truck Company, 3rd Amphibian Tractor Battalion, 1st Marine Division Third Marine Aircraft Wing Headquarters and Headquarters Squadron 33, Marine Aircraft Group 33 Headquarters and Maintenance Squadron 36, Marine Light Helicopter Transport Group 36 Marine Light Helicopter Transport Squadron 361, Marine Light Helicopter Transport Group 36 Marine Light Helicopter Transport Squadron 362, Marine Light Helicopter Transport Group 36 Marine Light Helicopter Transport Squadron 363, Marine Light Helicopter Transport Group 36 Marine Air Base Squadron 36, Marine Light Helicopter Transport Group 36 Marine Air Support Squadron 3, Marine Wing Headquarters Group Marine Attack Squadron 223, Marine Aircraft Group 15 Marine Observation Squadron 6, Marine Light Helicopter Transport Group 36 28 The Archives of the Commandant of the M~rine Corps, located at Marine Corps Headquarters in Washington, D.C., and the History and Museums Division, located at the Marine Corps Historical Center in the Washington Navy Yard, produced most of the information used to describe Project 52.1. Records with substantial information on Marine Corps activities at Desert Rock were stored in the classified archives of Fleet Marine Force Pacific, which was a superior authority of the Fourth Marine Corps Provisional Atomic Exercise Brigade. These records were destroyed in 1960, when the Fleet Marine Force Pacific disbanded its San Francisco records repository (4ti). Through document movement orders found at Marine Corps Head quarters, other potentially relevant documents were traced to the Federal Records Centers in Mechanicsburg, Pennsylvania, and Laguna, California. These repositories could only verify that the documents had been destroyed. Telephone interviews were conducted with members of the Operations Sections of Camp Pendleton, the home base of the Fourth Marine Corps Provisional Atomic Exercise Brigade, and of Camp Lejeune, the point of origin of several Marine Corps units that participated in Project 52.1. These interviews uncovered little additional documentation. The most important missing document for Project 52.1 at Shot HOOD is the Marine Corps After Action Summary Report. The Marine Corps Equipment Officer at Shot HOOD recalls in the weeks after HOOD drafting sections of an after action summary. However, the Commander of the Fourth Marine Corps Provisional Atomic Exercise Brigade does not recall receiving a completed report (33). Available Army after action reports on Shot HOOD include only cursory descriptions of Marine activities. One document that has been located for Project 52.1 is the project schedule of events, which was probably an annex to the 29 Marine Corps Operation Plan for Shot HOOD. This planning docu ment presents one of the few available detailed descriptions of Project 52.1 at HOOD. Normally such a document would be used to corroborate events described in an after action report. The unavailability of such an after action report has necessitated the use of the schedule of events in describing Project 52.1. Interviews with HOOD participants are used to verify the events listed in the schedule of events. Most of the other records available on Project 52.1 at Shot HOOD are operation orders, which also describe planned activi ties. However, without the Marine Corps after action report, there is little possibility of verifying whether these planned activities were in fact conducted and how their performance varied from the plans. This problem was also resolved in part by the use of interviews with project participants. Despite the uncertainties in personal recollection over 23 years that such an approach may generate, this is the only way to verify Marine Corps activities planned for Shot HOOD. Project 52.1 had five objectives (28): • To train command and staff personnel in planningand implementing operations necessitated bynuclear fires • To formulate new tactics and techniques relative to nuclear fires • To acquaint personnel with the effects of nuclear weapons • To test and evaluate U.S. military doctrine concerning nuclear warfare • To familiarize personnel with passive defense measures against the effects of nuclear weapons. Project 52.1 participation was planned so that some of the troops took part in a command post exercise, and others in a troop maneuver. The command post exercise was to start at noon 30 on the day before the shot and conclude no later than one hour before the detonation. Participants in the command post exercise would then join the rest of the Marines in observation trenches and await the detonation. Following the detonation, command post exercise personnel were to be transported to an equipment display area to view the effects of the nuclear detonation on Marine equipment and uniforms. The troop maneuver was a postshot exercise that involved the coordination of.an air-ground assault by a reinforced Marine battalion against a military objective. For safety reasons, the objective was located far from ground zero. Most Marine participants were to witness the shot from observation trenches in the forward area. Elements of one company, however, would observe the detonation from Loading Zone One with the helicopter squadrons. After the detonation, the helicopters were to transport these troops from Loading Zone One, as well as three companies and one artillery battery and the remainder of the first company from positions near the observation trenches, to landing zones near the attack objective. A ground assault on the objective, supported by artillery and tactical aircraft, would follow the airlift. In the meantime, a fourth company would march toward ground zero until it reached the radiological safety limit. That company would then return to the observation trenches, board helicopters for the airlift, and join the ground attack on the objective. A fifth company would be transported by vehicles to the attack objectives. After the ground assault was completed, all five Marine companies would be transported to the equipment display area to view the effects of the detonation. ' Originally, Project 52.1 was scheduled to take place during Shot DIABLO, on 27 June 1957, and the Fourth Marine Corps Provisional Atomic Exercise Brigade arrived at Camp Desert Rock on 19 and 20 June 1957. After orientation, a full rehearsal of the troop maneuvers planned for 27 June was held on 20-21 June in the 31 DIABLO exercise area. On 24 June, 311 officers and enlisted men from the Fourth Marine Corps Provisional Atomic Exercise Brigade observed Shot PRISCILLA (28). On 26 June, DIABLO was rescheduled for 28 June. The Marines began their command post exercise at 1200 hours on 27 June and completed it at 0300 on 2H June. The command post exercise personnel were then transported to the trenches to observe DIABLO with the rest of the Fourth Marine Corps Provi sional Atomic Exercise Brigade. At 0430 on 28 June, DIABLO failed to detonate because of electrical problems, and the Marines returned to Camp Desert Rock, as shown in figure 2-2. Shot DIABLO was eventually rescheduled for 12 July 1957. Because this delay would prolong the Marines' stay at Camp Desert Rock, it was decided to have the Fourth Marine Corps Provisonal Atomic Exercise Brigade perf6rm their troop test at Shot HOOD, scheduled for 3 July. Because of weather problems, HOOD was postponed and rescheduled for 0440 on 5 July. Several exercise facilities were modified to accommodate the high yield anticipated for Shot HOOD. The observation trenches for HOOD had to be quickly enlarged, since original plans for the shot did not call for the Fourth Marine Provisional Brigade to use them. The new trenches were 1.7 meters deep, and were located about 5,000 meters southwest of the HOOD ground zero (28). In addition, the DIABLO equipment displ~y was moved to the HOOD ground zero area. ~ources differ as to the location of the Marine equipment display area. An Exercise Desert Rock operation map (24) places it northeast of ground zero, as shown in figure 2-1. The total distances from ground zero to the end of the display area would then be about 4,230 meters. This placement would have situated 32 w w Figure 2-2: MARINES RETURN TO CAMP DESERT ROCK AFTER SHOT DIABLO FAILED TO DETONATE BECAUSE OF ELECTRICAL PROBLEMS the rear part of the display area in the foothills of the mountains northeast of HOOD shot-area. The Marine Brigade Equipment Officer who assembled the display questions this placement. In an interview, he recalled the display being entirely in flat terrain. Hilly terrain, he indicated, would have deflected the blast and would have had an adverse effect on the data the Marine Corps hoped to obtain from exposing equipment to Shot HOOD (35). He suggested that the display area was actually north-northwest of the HOOD ground zero, where the terrain is flat. The equipment display was designed to illustrate the effect of a nuclear detonation on Marine equipment and personnel.* The planned display area was probably 90 meters wide and extended to about 5,000 meters from ground zero, as shown in figure 2-1. The equipment, placed from 240 to 2,170 meters from ground zero, consisted of 69 pieces ranging from trucks and rocket launchers to telephones and radios . Four groups of four mannequins each were placed in various stances at distances ranging from about 3,800 meters to 5,000 meters from the shot-area (26). According to the Operation Order, the troop maneuver portion of Project 52.1 began at 2230 on 4 July. Because the command post exercise had been performed at DIABLO, it was not repeated at HOOD. The command post exercise participants were trucked with the maneuver troops to the trenches to observe Shot HOOD. Except for elements of G Company, the maneuver troops of the Second Battalion, Fifth Marines, left Camp Desert Rock in a fiveunit march column commanded by the Motor Transport Officer of Exercise Desert Rock (9; 13; 44). The first march column reached the trenches at 2353 on 4 July, and the last arrived at *The description of the display area is of the planned DIABLO display scaled to the HOOD shot conditions. 34 0045 on 5 July (24, Annex G). The trench area occupied by the Marines is shown in figure 2-3. The convoy vehicles r.etired to the parking area southeast of the command post on Mercury Highway, arriving 0133, awaited the HOOD there by and detonation. The remainder of G Company were trucked to Loading Zone One at Yucca Pass (27). Three helicopter squadrons, each consisting of eight helicopters of the Marine Air Group 36, left Camp Desert Rock at 2230 hours on 4 July for the trench area and they arrived at Loading Zone One, near the Yucca Pass airstrip, at about 2345 hours to aw~it the detonation (6). Because it is unlikely that the helicopters would have flown at night, they probably left Camp Desert Rock before sunset and arrived at Loading Zone One approximately ten minutes later. This assumption has been corroborated by Marine helicopter pilots (13; 38). According to the Project 52.1 schedule of events, personnel were in their assigned trenches at least 30 minutes before the detonation. The Marines were apparently positioned at H-hour as follows (27): • Second Battalion, Fifth Marines, less the attached units, and the Headquarters Battalion in the trenches • Detachments of the First Motor Transport Battalion, the Third Amtrac Battalion, and the First Anti-tank Battalion at the vehicle assembly area southeast of the command post exercise area • The Third Light Support Company and Desert Rock transport unit at the parking area on Mercury Highway • Marine Helicopter Squadrons 361, 362, and 363 of M~rine Air Group 36, Tnird Marine Air Wing, and G Company at Loading Zone One at Yucca Pass. The Location of Marine Observation Squadron 6 of the Marine Air Group 36 and the Marine Wing Headquarters Group has not been documented, but it can be assumed they were with the rest of the Third Marine Air Wing at Loading Zone One. 35 w 0' Figure 2-3: AERIAL VIEW OF TRENCHES TO BE OCCUPIED BY FOURTH MARINE CORPS ATOMIC EXERCISE BRIGADE DURING SHOT HOOD As a loudspeaker announced the countdown, observers covered their eyes and turned away from the detonation, as shown in figure 2-4. ~t 0440, Shot HOOD was detonated. The thermal discharge of the device ignited many brush fires and the blast wave caused some of the observation trenches to collapse. In the mining communities north of the NTS, windows shattered and buildings shook. The light from the detonation was seen in San Francisco, and the blast was felt in Los Angeles. Fifteen minutes after the detonation (0455), the maneuver troops left their trenches. With the exception of E Company, the Second Battalion, Fifth Marines, marched westward to Loading Zone Number Two, shown in figure 2-1, to wait for the helicopter airlift. In the meantime, Company E, led by its commanding officer and executive officer, formed two columns and marched northeast toward ground zero. Company E was preceded and accompanied by radiological safety monitors who measured the levels of radioactivity encountered. When Company E approached the 5 R/h* safety limit, they stopped and spent five to ten minutes in the area. They then marched back to Loading Zone Two near the observation trenches, arriving there at 0700 hours. The distance of the 5 R/h safety limit from ground zero has b een estimated at 360 meters by both participants (34) and an Army document (28). This estimate is questionable, however, because both radiological safety surveys and calculations of the unit rate of advance would place the 5 R/h line about 1,000 meters from ground zero (39) . At 0525, while Company E was on its march, parts of the Third Amtrac Battalion, preceded by Ontos vehicles of the First Anti-tank Battalion, left the vehicle assembly area and traveled to Loading Zone Number Two, where they picked up Company H and *Roentgens-per-hour. 37 w 00 ) ' ... Figure 2-4: BEFORE THE HOOD DETONATION, OBSERVERS COVERED THEIR EYES AND TURNED AWAY FROM THE SHOT SITE AS A LOUDSPEAKER ANNOUNCED THE COUNTDOWN transported them to Objective ALF4. Figure 2-5 shows one of the Ontos anti-tank vehicles. By 0700, Company H had attained its attack position and was conducting a ground assault against Objective ALFA, shown in figure 2-1 (27). Because dust obscured t he loading zone ne~r the trenches, the helicopters were unable to leave Yucca Pass until 85 minutes after the detonation at 0605. At 0615, the helicopters landed at Loading Zone Number Two, as shown in figure 2-6, and began the airlift of Companies H+S and F. Figure 2-7 shows Marines boarding one of the helicopters. Elements of Company G boarded at Loading Zone One and were transported directly to the landing zone. Company E joined the airlift when it returned from its march toward ground zero at 0700 (27; 34). The helicopters carried Company G to Landing Zone Blue, depicted in figure 2-1. Companies H+S, F, and E, and E Battery were flown to Landing Zone Pink, also shown in figure 2-1 . The airlift from Loading Zone Two to the two landing zones, Blue and Pink, was completed by 0821 ( 27). The helicopters were of the HRS-3 and the HUS types. Each had a crew of three: two pil ots and a crew chief. In addition , each carried five to s e ven Marines for this mission (13; 30; 38 ; 44). Since a round-trip required about 11 minutes, the airlift should have been comple ted in about two hours and six ~inutes, or at 0821. During the airlift, air support was provided by 24 F9F aircraft of Marine Attack Squadron 223, Marine Air Group 15 from the Marine Corps Air Station at ~ojave, California. The first of these aircraft, each flown by one pilot, arrived at the NTS at 0510. The aircraft provided close air support to the attack. The fighters, flying in groups of four, shuttled between Mojave and the NTS for approximately seven hours (3) and returned 39 Figure 2-5: THE MARINE CORPS ONTOS VEHICLE IS SHOWN WITH THE SHOT HOOD CLOUD IN THE BACKGROUND 40 .p ,_. Figure 2-6: MARINE CORPS HELICOPTERS LANDING "U> RECOVER MEN AND SUPPLIES AFTER THE DETONATION OF HOOD 0 0 0 :t 1 0 :t en a: w t