At least 14 mark

At least 14 mark-designated warheads were tested, plus additional developmental designs not yet awarded a serial number. These included the Mk/TX/XW - 7, 25, 31, 34, 35, 39, 41, 43, 46/53, 47, 49, 50, and 51. This series fired the largest tests since Ivy and Castle (and never equaled since in later U.S. tests) and led to the development and deployment of the largest U.S. weapon ever fielded, the 25 Mt Mk-41 bomb; and the largest U.S. missile warhead ever fielded, the W-53 9 Mt Titan-II warhead. An air dropped bomb variant of the W-53 was the largest (and oldest) weapon in the U.S. inventory up until its retirement in early 1997. The UCRL test of the W-47 Polaris warhead prototype was a major technological breakthrough that led to high yields in small light packages characteristic of all U.S. missile warheads today.

The extensive test schedule required the use not only of both atolls (Bikini and Enewetak) but Johnston Island also. This series was the last to conduct atmospheric testing at Bikini and Enewetak atolls. Test names were taken from North American trees and shrubs.

In 1958 the arms race preceded apace, with the enormous weapons production infrastructure and both weapons labs operating at full speed. Hardtack I included 35 tests, the largest test series so far (1958 in fact saw a total of 77 U.S. tests, more than the three previous record setting years combined). Partly this burst of testing activity was due to building pressure for an imminent test moratorium, leading the weapons labs to rush as many device types to the test range as possible. A total of 35.6 megatons were shot during this series.

The lab tests centered on ICBM and SLBM missile warheads and high yield strategic bombs. The DOD conducted high altitude multi-megaton tests to study their usefulness for ABM (anti-ballistic missile) warheads, and discovered the high-altitude EMP (electromagnetic pulse) effect in the process. Effects tests of underwater explosions were also conducted.

OPERATION HARDTACK was regarded as secret at the time and no one was allowed to have any cameras on board. It is rumored that photos were taken by the US Navy, but access to these photos has been denied at this time.

In February of 1958 the Tortuga participated in "Operation Hardtack" the thermonuclear weapons test series of that year conducted at Eniwetok and Bikini Atolls in the Marshall Islands. She transported equipment and supplies from San Diego to Eniwetok and Bikini and upon arrival provided shipping for cargo and personnel between the atolls while operating between Atolls @ about 0630 in the morning we ran aground a large "Coral Reef," as a result of the grounding the Tortuga sustained serious damage to the bow area.

She limped back to the States and had an escort ship part of the way, and proceeded to Oakland and went into to Dry-dock extensive for repairs.

In 1958 the arms race proceeded at a swift pace with the enormous weapons production infrastructure and both weapons labs operating at full speed. Hardtack I included 35 tests, the largest test series so far (1958 in fact saw a total of 77 U.S. tests, more than the three previous record setting years combined). Partly this burst of testing activity was due to building pressure for an imminent test moratorium, leading the weapons labs to rush as many device types to the test range as possible. A total of 35.6 megatons were shot during this series.

USS BOXER (CVS-21) FEB 58-AUG 58
USS COMSTOCK (LSD-19) DEC 57- APR 58
*USS TORTUGA (LSD-26) FEB 58-APR 58
USS BELLE GROVE (LSD-2 ) APR-58-AUG 58
USS MONTICELLO (LSD-35) APR 58-AUG 58
T-LST 618 SEP 57-DEC 58
T-LST 664 SEP 57-OCT 58
USS RENVILLE (APA-227) APR 58-MAY 58
USS MAGOFFIN (APA-199) MAY 58-JUN 58
USS NAVARRO (APA-915) JUL 58-AUG 58
USS FLOYD B. PARKS (DD-884) MAR 58-MAY 58
USS JOHN R. CRAIG (DD-885) MAR 58-MAY 58
USS ORLECK (DD-886) MAR 58-MAY 58
USS PERKINS (DDR-877) MAR 58-MAY 58
USS MANSFIELD (DD-798) MAY 58-AUG 58
USS COLLETT (DD-730) MAY 58-AUG
USS DEHAVEN (DD-727) }MAY 58-AUG 58
USS BENNER (DDR-807) MAY 58-AUG 58
USS EPPERSON (DDE-719) AUG 58-AUG 58
USS CHANTICLEER (ASR-7) APR 58-MAY 58
USS GRASP (ARS--24) MAR 58-JUN 58
USS BOLSTER (ARS-38) MAR 58-JUN 58
USS MOCTOBI (ATF-105) FEB 58-JUN 58
USS ARIKARA (ATF-98) MAR 58-AUG 58
USS TAKELMA (ATF-113) MAR 58-AUG 58
USS MUNENSEE (ATF-107) MAR 58-JUN 58
USS CHOWANOC (ATF-100) MAR 58-JUN 58
USS CREE (ATF-84) APR 58-AUG 58
USS HOOPER ISLAND (ARG-17) APR 58-JUN 58
USS CACAPON (AO-52) MAR 58-AUG 58
USS LANSING (DER-388 ) MAY 58-AUG 58
USS JOYCE ( DER-317 ) MAY 58-JUN 58
USS SILVERSTEIN (DE-534) SEP 58-SEP 58
USS REHOBOTH ( AGS-50) APR 58-JUN 58
USS LAWRENCE CTY (LST-887) MAY 58-JUN 58
USNS AINSWORTH (T-AP-181) APR 58-JUL 58
USS BONITA (SSK-3 ) APR 58-JUN 58
USS KARIN ( AF-33 ) MAR 58-AUG 58
USS MERAPI ( AF-38 ) MAR 58-AUG 58
USS COGSWELL (DD-651) JUL 58-AUG 58
USS SAFEGUARD (ARS-25) JUL 58-AUG 58
USS HITCHITI (ATF-103) JUL 58-AUG 58
USS TILLAMOOK (ATF-102) JUL 58-AUG 58

Stationed aboard the USS Tortuga-26 during Operation Hardtack

Date: Fri, 24 Jul 1998
Subject: Hardtack

I served aboard the Tortuga from 1956 to late 1959 and was on board the Tortuga "Feb. 58-Apr.58" as shown in the list of ships involved in operation Hardtack.

To the best of my knowledge we were not involved in any detonations.

We transported a lot of equipment in our well deck and it was always covered with large tarps. When we would inquire about it, we were told that it was "top secret."

In 1958, you did not question anything; you just carried out your orders and kept your mouth shut.

We did have liberty call on Eniwetok or Bikini and played baseball and swam in the water. We were instructed "not" to eat the coconuts.

It is kind of ironic, because I was just talking to one of my former shipmates on the telephone yesterday about this operation. We did not remember what it was called, but were curious about all the secrecy.

Charles R. Westbrook
Evansville, IN.

Stationed aboard the USS Tortuga-26 during Operation Hardtack
Subject: Atomic veteran (Operation Hardtack)
Date: Thu, 6 Aug 1998

I'm 59 years old until January 1999. I was involved in operation Hardtack in 1958 aboard the USS Tortuga LSD. I was an electrician third class and worked mainly on the switchboard.

Some of my shipmates were Bob Ward, Bill? Baker and Doug Marshall. After forty years my memory on the subject isn't much. I remember we had a beer party on Japan before the exercise. I remember wearing film badges to detect radiation during the operation.

The ship was fitted with a wash down system for contamination from the nuclear test. After the exercise and partly way to port we ran aground on a coral reef. This put a hole in the bow big enough to run a truck through. The force in which we hit the reef was such that it knocked everyone out of their bunks. Damage control patched the ship and due to it having so many ballast tanks we did not sink. We hotfooted it to San Francisco at 12 knots for repairs. This is about all I remember.

I'm adding an attachment. It's a copy of the parchment certificate I received for being a part of the exercise.

Sincerely,

James Oneyear

Date: Tue, 13 Mar 2001
Subject: Military Service in Eniwetok (Operation Hardtack 1-1958)

I served on the USS Tortuga (LSD26) during operation Hardtack. We left the area prior to the nuclear blasts, however I recall signs posted on the atoll advising, "Don't eat the coconuts. Radioactive”. Also I recall all the native islanders were relocated. But we did our service on the atoll. I married my first wife in 1965. My first son was stillborn; my daughter has a cleft lip/palate. I, to this day wonder if my service in Eniwetok had something to do with that. Second marriage, two sons seem normal.

George Tower

Operation Hardtack

HARDTACK was the designation given to the atmospheric nuclear weapon test conducted by the United States in the Pacific Ocean and in Nevada in 1958. Operation HARDTACK I was a series of 35 tests, all but two of which were detonated at Enewetak and Biking atolls in the Marshall Islands, the Atomic Energy Commission's (AEC) "Enewetok Proving Ground" (EPG). The other two were detonations at 42 and 76 km above Johnston Island, which lies about 700 miles (1,296 km) west-southwest of the Hawaiian Islands.

A joint military conducted the tests and civilian organization designated Joint Task Force 7 (JTF 7. JTF 7 was a military organization in form but was made up of military personnel, Federal civilian employees, and contractors of the Department of Defense (DOD) and the AEC. The commander of this force was the appointed representative of the AEC and reported also to the Joint Chiefs of Staff (JCS) and the Commander in Chief Pacific (CINCPAC)

During HARDTACK the United States fired as many nuclear devices (35) as had been fired in all prior Pacific Ocean tests. Not only was the total number of shots in HARDTACK large but also the variety of types was great; land - and water - surface events, underwater detonations and balloon - and rocket - born high-altitude tests were conducted. The following page of this fact sheet lists the names, dates, and locations of the shots.

In a sense, HARDTACK was divided into three parts. The first was aimed at the development of nuclear weapons continuing the type of testing that had taken place at Enewetak and Bikini during the early and mld-1950s. In these tests, the AEC weapon development laboratories (Los Alamos Scientific Laboratory and the University of California Radiation Laboratory) detonated their experimental devices with the DOD providing support and conducting experimental that did not interfere with the AEC Activities.

The second part sponsored by DOD, consisted of the underwater test shots, WAHOO and UMBRELLA, the first in the open ocean and the second within the lagoon at Enewetak. The purpose of these tests was to improve the understanding of the effects of underwater explosions on Navy ships and material. These tests could be considered as the continuation of BAKER test of the CROSSROADS series at Bikini in 1946 and the WIGWAM test 500 miles (927) km) off the U.S. West Coast in 1955.

* Formerly Eniwetok. The spelling of Marshall Island place names has changed in recent years in order to more accurately render the sounds of the Marshall Island names using English spelling.

The third part. Also sponsored by DOD, addressed a military problem that was newer: nuclear weapons in air and ballistic missile defense. The HARDTACK tests directed toward this problem consisted of three high-altitude shots, two of which (TEAK and ORANGE) were rocket borne and were conducted at Johnston Island. The third of these high-altitude tests YUCCA was carried aloft by a balloon over the ocean between Enewetak and Bikini. These high-altitude tests used device placement techniques and data-recording operations that were new to nuclear weapons testing.

Central to the test series was the experimental program. This program and its requirements dictated the form of the test organization and the detail of personnel participation. HARDTACK's experiments program incorporated two aspects. The first of which was the development of the weapons themselves, and the second involved the measurement of the explosive and radiation effects. Unlike earlier nuclear test series, the HARDTACK test operations supporting each aspect were in large part separate.

These two aspects can serve as a rough measure of differentiation of interest between the major participants: the AEC interest in weapon development and the DOD interest in the military application of the effects of the explosions. The several parts of the weapon development and effects studies each had particular features that led to the possibility of radiation exposure.

For Operation HARDTACK, CJTF 7 was directed to "assume overall responsibility for the radiological safety of Task Force personnel and of populated lslands." To carry out this responsibility the JTF 7 Operation Plan further directed that a Fallout plotting Center be set up and that the capability be established to keep the task force and CINCPAC informed of the fallout situation at all times, including the announcement of safe reentry times. Fallout stations were to be set up and technical assistance given to personnel in the Trust Territory of the Pacific Islands. Monitors and couriers were to be provided for radioactive sample centers.

In addition, the Operation Plan specified that task group commanders establish radiation safety (radsafe) units within the task groups with adequate special clothing and radlac instrumentation. Task groups were also to provide a roster of their personnel for film badge preparation.

The radsafe program for Operation HARDTACK was divided into two parts: onsite and offsite. Onsite radsafe activities were conducted by the various task groups, with the scientific task group given the responsibility for all radsafe functions associated with diagnostic experimental programs and for dosimeter and other technical services to the entire task force. The operation of the offsite program and the coordination of the onsite activities were conducted by the Radsafe Office of HQ JTF 7.

A maximum permissible exposure MPE) for personnel was set at 3.75 roentgens (R) (gamma only) per consecutive 13 - week period with a maximum of 5 R for the operation.

Exceptions were made for emergency and other tactical situations. The operation was defined as the period from 15 days before the first ready date to 15 days after the last shot. A special MPE of 10 R was authorized for crewmembers of air - sampling aircraft. In the event of operational error or emergency, an additional exposure of 10 R would be accepted. Any exposure in excess of 20 R total would be considered as on overexposure for aircrew samplers.

The limit of 3.75 R per 13-week period was slightly greater than the National Council on Radiation Protection and Measurements and the International Commission on Radiation Protection limit of 3 R per 13 - week period In effect at that time. The limit of 5 R for the Operation is equivalent to the exposure currently permitted per year by Federal guidelines for radiation workers. Appropriate remarks were to be included in the medical records of personnel who exceeded the 3.75 and 5 R limits. Military personnel were to be advised that they should not be exposed to further radiation until sufficient time elapsed to bring their average radiation exposure down to 0.3 R/week. Civilian personnel in this category were to be informed that limitations on further radiation exposure were to be determined by the laboratory or agency having administrative jurisdiction over such personnel.

A film badge program provided an exposure - indicating device to all JTF 7 personnel to maintain complete exposure information on everyone entering the EPG during the operation. The commander of the scientific task group assigned overall badging responsibility to a special task unit. Beginning 1 April 1958, film badges were issued to all individuals upon their arrival at the EPG with instructions that the badge be worn at all times and turned in on recall, upon exit from any contaminated area, or upon departure from the EPG.

The table on the following page documents the numbers and percent of task force personnel who received exposures in various categories. These data are based on the latest data available and may be added to as research is completed. Of the some 19.600 individuals badged at HARDTACK, 99 percent had exposures that did not exceed the current Federal guidelines of 5 R per year. The highest recorded exposure for the series was 12.41 R. The overall joint task force mean exposure was 0.87 R.

During the conduct of the series only one incident occurred of an exposure of a large group of JTF 7 personnel to significantly elevated radiation levels. This happened on 14 May when the base islands (Enewetak and Parry) at Enewetak Atoll received fallout from a test shot that had been detonated at Bikini two days before. This fallout episode, which lasted about 60 hours, could have contributed as much as 1.2 to 1.5 R total dose to personnel on Enewetak Atoll depending upon the island on which they lived and their work activities, however. since nearly all personnel wore film badges, this fallout exposure is reflected in the film badge doses.

There was one known incident of offsite fallout. Two Japanese research vessels operating outside the danger area set up around the EPG detected an increase in radiation after shot POPLAR. An investigation by the JTF 7 Staff Surgeon revealed that this exposure was small amounting to; at most 0.085 R for the crew, and even this figure did not reflect the decontamination procedures that were used to lower the contamination.