Science

In the 1960s, the U.S. ran nuclear tests and dumped radioactive waste off Johnston Atoll. After decades of being uninhabited, it became a refuge for hundreds of species

Once a hazardous Cold War nuclear site, this tiny Pacific atoll is now a flourishing sanctuary for nearly 500 species.

Eric Baker/USFWS, Pacific Islands

Update: Jul 28th, 2026 11:52 EDT

Nestled deep in the Pacific Ocean lies Johnston Atoll—a tiny patch of land with a dark past. Once the site of botched nuclear tests and ocean-dumped radioactive waste, it is now one of the most remote wildlife refuges on Earth.

Johnston Atoll is located between the Marshall Islands and Hawaii. It is an unincorporated territory of the United States. Johnston Island was used by the U.S. military from 1934 until 2000.

During the peak of the Cold War (1962), the United States decided to run a nuclear test series of 36 detonations in the Pacific, codenamed Operation Dominic. Ten rockets successfully detonated at Johnston Atoll, while four failed to launch properly and caused major radioactive contamination. Debris from these tests was dumped directly into the Pacific Ocean.

Johnston Atoll Radiological Survey (JARS) noted: “Sea-disposal of radioactive waste for control of the radiological hazard was then considered proper.”

In the 1960s, the U.S. ran nuclear tests and dumped radioactive waste off Johnston Atoll. After decades of being uninhabited, it became a refuge for hundreds of species

Radioactive Contamination at Johnston Atoll

The four rockets that failed during their launch sequence were Bluegill (June 1962), Starfish (June 1962), Bluegill Prime (July 1962), and Bluegill Double Prime (October 1962).

Bluegill

Bluegill was destroyed by the safety team after the tracking ship lost contact with it. The missile was destroyed at a high altitude roughly 22 miles south of the atoll, and no local contamination was recorded.

Starfish

The first major contamination incident came with Starfish. The launch of a Thor missile carrying a nuclear warhead was aborted a minute into its flight, and a self-destruct order blew the missile apart at an estimated altitude of 30,000 feet. Large pieces of radioactive debris fell back to the island.

In 2000, the U.S. Defense Threat Reduction Agency (DTRA) conducted the Johnston Atoll Radiological Survey (JARS), which noted: “More debris landed in the surrounding waters and on adjacent Sand Island, where residual plutonium from the test device was found. A large collection of alpha contaminated scrap was isolated during the initial cleanup… It is likely that residual plutonium, in addition to that recovered from Sand Island, fell into the waters of JA.”

Bluegill Prime

Bluegill Prime caused the most severe contamination of all the failed tests. Due to a system malfunction on the launch pad, officials destroyed the rocket before it could lift off. The resulting explosion scattered debris across the atoll.

The U.S. DTRA radiological study describes the Bluegill Prime disaster: “Plutonium material mixed with the flaming fuel drained into trench cables and was carried away in the smoke from several fires. This resulted in a deposition of alpha contamination on the launch pad complex that represented a major contamination problem. Contaminated debris was scattered throughout the wire-enclosed pad area and neighbouring areas.”

“Metal revetment buildings were highly contaminated with alpha activity... Fuel, which spilled and flowed over the compacted coral surrounding the launch mount and revetments resulted in highly contaminated areas. Prevailing winds at the time of the destruction caused general contamination of all areas downwind of the launch mount,” the DTRA study added.

Bluegill Double Prime

During this last test, the rocket was destroyed at a height of 109,000 feet after it malfunctioned 89 seconds into the flight. US Defence Department officials confirm its destruction contributed to the radioactive pollution on Johnston island.

Uninhabited Since 2004

Johnston Atoll’s military history began before World War II and continued until the island was decommissioned in 2004. At one time, over 1,200 military and contractor personnel lived on Johnston. Today, the atoll is uninhabited, except for periodic visits by U.S. Fish and Wildlife Service.

Hundreds of species living in Johnston Atoll National Wildlife Refuge

Johnston Atoll National Wildlife Refuge is home to numerous species. The low coral island is vegetated by herbs and grasses tolerant of the arid climate. The wildlife found in and around the island is rich in diversity, ranging from a wide variety of birds to marine mammals, reptiles, invertebrates, marine life, and flora.

A refuge for seabirds, Johnston Atoll National Wildlife Refuge is home to the largest red-tailed tropicbird colony in the world! Sound On: Adorable red-tailed tropicbird chick puts on its big bird voice as it practices vocalizations 🔊📹 by Stefan Kropidlowski/USFWS pic.twitter.com/urlwVHvVng
— USFWS Migratory Birds (@USFWSBirds) December 7, 2023

At least 300 species of fish have been recorded within the reefs of Johnston Atoll. Additionally, approximately 93 species of algae and 54 species of coral have been identified there. The atoll is also home to 14 species of seabirds.