1946 "Crossroads" Nuclear Test Report

LTC (Ret) Boley Caldwell III was a member of the U.S. Army Corps of Engineers assigned duties as a Radiological Safety Monitor during his participation at "Crossroads" (JTF-1).

He presently serves as the NAAV Medical Data Base Custodian and Crossroads Coordinator.

National Association of Atomic Veterans
Fact Sheet


In July 1946 Joint Task Force - One was assembled on order from the Joint Chiefs of Staff with almost 42,000 military and scientific personnel to conduct various tests in conjunction with the detonations of three Atomic Bombs at Bikini Atoll in the Marshall Islands. The three detonations would be the fourth, fifth and sixth Atomic bombs ever detonated. The three tests were designated by code names Able, Baker, and Charlie. Test Able was scheduled for an air drop delivery and the bomb was to be detonated at an altitude of 520 feet above the 95 assembled target ships inside Bikini Lagoon. Test Baker was to have the device suspended under water from the LSM-60 and detonated at a depth of 90 feet below the surface of the lagoon. Test Charlie was to be a deep underwater detonation outside the ring of islands comprising Bikini Atoll. Unforseen events during the Baker test eventually resulted in the cancellation of Test Charlie.

The tests during Operation Crossroads were designed to produce information not previously available from the Trinity Test or from the operational employment during Word War II at Hiroshima and Nagasaki, Japan. Basic data on Yield (TNT equivalent), Blast (overpressure), Heat (thermal intensity), and Radiation (both initial and residual effects) were to be collected in a detailed scientific manner. In addition to the weapons effects, aircraft attack techniques and naval ship design criteria were to be studied.

Test Able was conducted on 1 July 1946 utilizing the air drop delivery from a B-29. A total of five ships were sunk and 12 others sustained severe to moderate damage. Much data was never collected because the bomb missed it's designate aiming point by some 1500 yards. Residual radiation effects of Test Able were short lived and preparation for Test Baker were commenced on 3 July 1946.

The atomic device for Test Baker was detonated on the morning of 25 July 1946. Upon detonation the assembled troops and observers witnessed the rise of a column of water out of the surface of the lagoon that was nearly a mile high and a half mile in diameter. After the upsurge and displaying it's mushroom crown, the water began it's descent back to the lagoon surface and in so doing produced a giant rolling fog termed "Base Surge" which eventually engulfed the entire target ship fleet. This Base Surge contained the radiation equivalent to tons of Radium. The radiation components were fission fragments (split Uranium and Plutonium atoms) and unfissioned Plutonium. All of these components were highly radioactive with not only Gamma and Beta emitters but also with undetectable Alpha emissions

From the 25 of July until the 30 of July the Lagoon Patrol and Initial Boarding Teams were busy trying to work their way around the intense fields of radiation to beach sinking ships, retrieve test instruments and evacuate animals from the target ships for further study.

On July 31 the Navy began it's vain attempts to decontaminate the target ships in order to reboard them. Much manpower and effort was expended attempting the decontamination of a number of the target ships for the next 10 days with very little reduction of radiation intensities. Basic radiation safety precautions were ignored during this attempt to reoccupy the target fleet. On 10 August 1946 the commander of JTF-1, Vice Admiral W. H. Blandy ordered all attempts at decontamination to cease. The discovery of wide spread Plutonium contamination (an Alpha emitter) on all but 12 of the target ships was the reason for halting the decontamination efforts.

Three days later on 13 August 1946, the Task Force Commander with most of his staff departed for the United states on the USS McKinley AG-7. The remainder of August was spent towing the target ships from Bikini Lagoon to Kwajalein Atoll where the radiation levels could be reduced for the crews of support ships and a personnel decontamination barge could be put into operation. Beginning on 1 August 1946 specially assembled work parties went to work removing the live ordinance from target ships. These Ammunition Removal Teams operated well into March of 1947.

Eight of the major ships and two submarines were towed to ports in the United States for further radiation studies. Twelve of the target ships were safe enough to reman and were sailed back to the United States. The remaining sixty odd target ships were sunk at various locations around the Pacific.

On 1 November 1946 JTF-1 and Operation Crossroads was deactivated and all further operations were at the direction of the Joint Chiefs of Staff

For thirty-three years following the Operations Crossroads, nothing was done by the United States government to follow-up on the possible adverse health effects of atomic veterans. In 1978 Congress directed DOD to establish a registry of test participants for all atmospheric tests conducted by the United States from 1945 through 1962.

Almost immediately the DOD action agency for this project, the Nuclear Test Personnel Review Board of the Defense Nuclear Agency, placed all emphasis on Gamma radiation exposure. Millions were spent in studies to establish a "Reconstructed Dose Level" of all veterans. The real problem at Crossroads and at many of the other tests was the inhalation and/ or ingestion of Alph emitting particles. This internal contamination has been shown time and again to be the real cause of veteran's health problems.

In 1988 the first effective legislation for Atomic Veterans was signed into law. Public Law 100- 321 functions on the Rule of Presumption, ie, if a veteran was at any of the atmospheric tests conducted from 1945 thru 1962 and contracts one of [the presumptive] cancers, he is entitled to compensation and treatment. These veteran's widows likewise are eligible for compensation. Until the DVA discontinues the use of "Reconstructed Gammma Doses" and PL100-321 is interpreted by the DVA or expanded by Congress to include other radiogenic illnesses of Atomic Veterans, there can be little hope for an equitable solution to this problem.

LTC(Ret) Boley H. Caldwell III
Operation Crossroads Coordinator