Johnston Atoll is a remote, uninhabited coral atoll roughly 1,300 kilometers southwest of Honolulu, notable for one of the most paradoxical histories of any place on Earth. Over the course of the twentieth century, the United States used it as a military airfield, a nuclear weapons test site, a storage depot for Agent Orange, and the country’s first chemical weapons incinerator. Then, within about a year of the base closing in 2003, nearly every structure was demolished, the personnel left, and the atoll was folded into a sprawling marine national monument. Today it sits empty of people, its contaminated soils slowly weathering under seabird colonies and the watchful surveys of NOAA researchers.
A Tiny Place With an Outsized Military Past
In purely geographic terms, Johnston Atoll is not much. The atoll consists of four small land masses: Johnston Island and Sand Island, the two natural islets, plus two artificial islands called North Island (Akau) and East Island (Hikina) that the military built by dredging coral from the surrounding reef flat. At its peak, the total dry land area was only about 260 hectares, and much of that was runway, storage buildings, and industrial infrastructure. The atoll sits alone in the central Pacific, hundreds of kilometers from the nearest island group, which gave it a strategic value far out of proportion to its size. Its isolation made it ideal for the kinds of activities the military preferred to keep far from populated areas.
The U.S. military presence began in the 1930s, and Johnston quickly became a multi-purpose installation. Over the following decades it served as a naval refueling station, an airfield, a missile launch site, and a hazardous materials processing center. At its operational peak the base housed around 1,200 personnel, complete with a bowling alley, a dive club, and its own television station. The remoteness that made it strategically useful also made it ecologically unusual: Johnston Atoll supported large colonies of tropical seabirds, green sea turtles, and a surrounding reef system that, when left alone, thrived in warm, clear central Pacific waters.
Nuclear Testing and Starfish Prime
Johnston Atoll’s most dramatic chapter began in the late 1950s and early 1960s, when the U.S. conducted a series of high-altitude nuclear weapons tests from the island. The most famous of these was Starfish Prime, a 1.4-megaton thermonuclear warhead detonated roughly 400 kilometers above the atoll on July 9, 1962. The test was not designed to destroy anything on the ground. Instead, it was intended to study the effects of a nuclear explosion in near-space, and the results exceeded what most scientists expected.
The detonation created a transient diamagnetic cavity in Earth’s magnetic field and launched an electromagnetic pulse that was detected around the globe.1Journal of Geophysical Research: Space Physics. Particle‐In‐Cell Simulations of Starfish Prime The EMP knocked out streetlights in Hawaii, disrupted radio communications across the Pacific, and damaged several satellites in low Earth orbit. The blast also injected energetic particles into Earth’s radiation belts, creating an artificial belt of trapped radiation that persisted for months and degraded the electronics of additional satellites over time. Starfish Prime remains one of the defining events in the history of electromagnetic pulse research, and scientists continue to model its effects using modern simulation tools decades later.
Several other nuclear tests launched from Johnston in this period also went badly. At least three test rockets malfunctioned shortly after launch. One was deliberately destroyed at low altitude, scattering plutonium and other radioactive debris across the island and the surrounding reef. These failed tests left behind contamination that complicated the site for decades.
Agent Orange and Chemical Weapons Incineration
As if nuclear contamination were not enough, Johnston Atoll gained a second toxic legacy in the 1970s. In 1972, in response to a directive to return all remaining Agent Orange stockpiles from Southeast Asia to the continental United States for disposal, military officials instead shipped the herbicide to Johnston Atoll.2SAGE Journals (Journal of Contemporary History). Imperial Ruin and Military Waste on Johnston Atoll The rationale was largely political: no community on the U.S. mainland wanted to host thousands of barrels of a dioxin-contaminated defoliant. Johnston, with no civilian population and minimal media visibility, became the default destination.
The herbicide sat on the atoll in deteriorating storage for years. Eventually the Agent Orange stocks were incinerated at sea aboard a specially equipped ship in 1977, but this was only the beginning of Johnston’s role as a disposal site. Through the 1980s, the atoll was transformed into the home of the Johnston Atoll Chemical Agent Disposal System (JACADS), the U.S. military’s first full-scale facility for incinerating chemical munitions.3SAGE Journals (Journal of Contemporary History). Imperial Ruin and Military Waste on Johnston Atoll The plant burned thousands of tons of nerve agents and mustard gas stored in aging Cold War-era weapons. Operations at JACADS continued until 2000, processing the bulk of the American military’s Pacific-stored chemical arsenal. The facility served as a prototype for later chemical demilitarization plants built on the mainland.
The decision to concentrate so many kinds of hazardous waste on one small atoll was a product of Cold War-era thinking about remote territories. Johnston had no voting population, no congressional representation, and virtually no press coverage. It was, in a bureaucratic sense, the path of least resistance. That convenience came at an environmental cost that the military would spend years trying to address.
Reef Destruction From Dredging
The military’s physical reshaping of Johnston Atoll was as dramatic as its chemical contamination. To expand the runway and create the two artificial islands, the Army Corps of Engineers conducted massive dredging operations in the 1960s. This work directly destroyed about 440 hectares of coral reef, but the damage did not stop at the dredge lines. Over 2,800 hectares of nearby reef were also affected by sedimentation, altered water flow, and the general disruption of dredging operations.4PLOS Biology. Dredging in the Spratly Islands: Gaining Land but Losing Reefs For context, 440 hectares is roughly the size of a large urban park, and the broader affected area was about six times that.
The dredging example at Johnston has become a reference point in modern debates about military reef destruction elsewhere in the Pacific. When researchers assessed the environmental effects of Chinese dredging in the Spratly Islands, they explicitly cited the Johnston case as a precedent showing that reef impacts extend far beyond the footprint of the dredging itself.5PLOS Biology. Dredging in the Spratly Islands: Gaining Land but Losing Reefs Sediment plumes smother coral polyps, reduce light penetration, and alter the substrate that juvenile corals need to settle on. The effects can persist for years after dredging stops, especially in shallow lagoon environments where sediment does not flush out quickly.
The Sudden Closure
After the chemical weapons incineration wrapped up, there was little reason to keep the base running. Johnston Atoll went from a fully operational military installation with 1,200 personnel to complete demolition and abandonment within roughly a year after the base closure in 2003.6Academic Press (ScienceDirect). Current Status of the US Military Atolls in the Pacific: Johnston and Wake Most buildings were torn down, the runway was decommissioned, and the infrastructure that had supported a small town’s worth of people simply vanished. Both Johnston Atoll and Wake Atoll had been active U.S. military bases since the 1930s, and both carried a legacy of contaminants in the soil and ocean sediments.7Academic Press (ScienceDirect). Current Status of the US Military Atolls in the Pacific: Johnston and Wake
The speed of the departure was striking. Military base closures on the mainland typically take years of environmental review, community negotiation, and phased redevelopment. At Johnston, there was no community to negotiate with and no redevelopment plan. The buildings came down, the hazardous materials were consolidated or removed, and the personnel flew out. What remained was a flat, cleared landscape of coral rubble and concrete pads, slowly being reclaimed by vegetation and wildlife.
Johnston Atoll is now part of the Pacific Remote Islands Marine National Monument, a vast protected area encompassing several remote atolls and islands administered by the U.S. Fish and Wildlife Service. NOAA conducts periodic monitoring of the surrounding reefs and marine life as part of long-term ecosystem assessments across the Monument’s islands.8NOAA Institutional Repository. Coral Reef Ecosystem Monitoring Report for the Pacific Remote Islands Marine National Monument 2000 – 2017: Chapter 6 Johnston Atoll No one lives on the atoll. Visits are restricted to researchers and government personnel, and even those are infrequent.
Seabird Colonies and Ecological Recovery
Despite decades of military activity, Johnston Atoll has long supported significant seabird populations, and the birds have been the subject of some of the longest-running ecological studies in the tropical Pacific. A 17-year capture-mark-recapture study of brown boobies found annual adult survival of about 90%, a figure that held remarkably steady across the entire study period.9Oxford Academic. Survival of Brown Boobies (Sula Leucogaster) at Johnston Atoll: A Long-Term Study Researchers noted that this survival rate did not fluctuate with El Niño events or other ocean-wide disturbances, which is unusual for tropical seabirds whose food supply depends on ocean conditions.
The likely explanation is Johnston’s peculiar oceanographic setting. The atoll sits in a region of the central Pacific that tends to be buffered from the worst El Niño-related disruptions to sea surface temperature and productivity. While seabird colonies on islands closer to the eastern Pacific or the equator can suffer dramatic breeding failures during strong El Niño years, the waters around Johnston appear to remain relatively stable.10Oxford Academic. Survival of Brown Boobies (Sula Leucogaster) at Johnston Atoll: A Long-Term Study This makes the atoll something of a natural laboratory for studying baseline seabird biology without the complicating variable of cyclical ocean disruption.
Beyond brown boobies, Johnston supports breeding colonies of red-footed boobies, masked boobies, great frigatebirds, red-tailed tropicbirds, brown noddies, and several species of terns and shearwaters. The removal of military personnel and the cessation of nighttime lighting (which disorients nesting seabirds) has allowed some populations to expand into areas that were previously occupied by buildings and equipment. The atoll’s location on the fringe of the Hawaiian archipelago also makes it an important waypoint for migratory shorebirds moving between breeding grounds in Alaska and wintering areas farther south in the Pacific.
Yellow Crazy Ants and the Invasive Species Problem
One of the most pressing ecological threats to Johnston Atoll today has nothing to do with nuclear fallout or chemical residues. It comes from yellow crazy ants, an aggressively invasive species that arrived on the atoll during its years of heavy military shipping traffic and has since established itself across several islets. Research comparing 46 sites of varying ant abundance found that ground-nesting seabirds, particularly brown noddies, declined sharply as yellow crazy ant numbers increased.11Conservation Science and Practice. Drivers of variation in yellow crazy ant (Anoplolepis gracilipes) abundance and impacts on native fauna in an atoll ecosystem
What makes the finding especially troubling is that these impacts were observed even when ant densities were relatively low. Invasive ant species harm ground-nesting birds through several mechanisms: they swarm and attack chicks and incubating adults, they disrupt the arthropod food web that many seabird species rely on, and they displace native land crabs that play a role in nutrient cycling and seed dispersal on atoll ecosystems. The study’s authors concluded that active control or eradication of yellow crazy ants may be needed to restore healthy seabird and terrestrial crab populations at Johnston.12Conservation Science and Practice. Drivers of variation in yellow crazy ant (Anoplolepis gracilipes) abundance and impacts on native fauna in an atoll ecosystem
Eradicating invasive ants from a remote atoll presents logistical challenges that mirror the difficulties of any conservation work at Johnston. Every piece of equipment, every bait station, and every researcher has to be transported over a thousand kilometers of open ocean. There is no permanent staffing on the island, so any control program has to be designed around infrequent expeditions or autonomous delivery systems. Yellow crazy ants have proven extremely difficult to eradicate on other Pacific islands, and their ability to form supercolonies that cooperate rather than compete with each other makes localized treatment less effective than it would be for more territorial ant species.
Contamination That Stays Behind
The environmental cleanup at Johnston Atoll is an ongoing and incomplete process. When the military departed, it left behind soil contaminated with radioactive materials from the failed nuclear test launches, dioxin residues from the Agent Orange storage period, and various heavy metals and industrial chemicals from decades of base operations. Some of the most contaminated soil was consolidated and capped in place rather than removed, on the theory that shipping large volumes of radioactive or toxic material across the Pacific posed its own risks.
The ocean sediments around the atoll carry their own contamination history. Decades of industrial runoff, fuel spills, and incinerator operations left traces in the nearshore environment. The extent to which these contaminants have moved through the marine food web is still being studied, but the surrounding coral reefs, while heavily damaged by the dredging of the 1960s, have shown signs of gradual recovery in the decades since. NOAA’s monitoring efforts track coral cover, fish biomass, and water quality across the atoll as part of the broader Pacific Remote Islands Marine National Monument assessment program.13NOAA Institutional Repository. Coral Reef Ecosystem Monitoring Report for the Pacific Remote Islands Marine National Monument 2000 – 2017: Chapter 6 Johnston Atoll
The practical challenge is that Johnston Atoll’s contamination does not fit neatly into standard environmental remediation frameworks. Superfund-style cleanups assume a site will eventually be returned to some productive use, whether residential, commercial, or recreational. Johnston has no such future. No one will live there, no developer wants the land, and the cost of a full remediation to residential standards would be staggering for a place with no human occupants. The result is a kind of managed abandonment: the worst contaminants are contained, the wildlife is monitored, and the atoll is left to slowly process its toxic inheritance on its own timescale.
Cultural and Historical Layers
Before the military arrived, Johnston Atoll had a longer if less well-documented human history. NOAA researchers have compiled archival records of pre-twentieth-century connections to the atoll, including its discovery by European and American sailing vessels in the early 1800s and its occasional use by guano miners in the mid-nineteenth century.14NOAA Repository. Early Cultural and Historical Seascape of the Pacific Remote Islands Marine National Monument The guano trade was a significant economic force in the Pacific during that era, and Johnston’s phosphate-rich deposits attracted brief periods of commercial interest before the U.S. formally claimed the atoll.
Hawaiian and Polynesian navigators were likely aware of the atoll long before Western contact, though permanent settlement was never feasible given the lack of fresh water and the tiny land area. The atoll sits within the broader cultural seascape of the Hawaiian Islands, and its history is intertwined with Polynesian patterns of long-distance ocean voyaging, even if it was never a destination in the way that larger, habitable islands were. Today, the primary cultural significance of Johnston lies in its military history and the environmental questions it raises about how nations use remote territories they consider expendable.
Why Johnston Is Difficult to Visit
Unlike some protected marine areas that allow limited tourism or research visits, Johnston Atoll is effectively closed to the public. The U.S. Fish and Wildlife Service manages the atoll as part of the National Wildlife Refuge system, and access requires special permits that are rarely granted outside of government-sponsored research missions. There is no harbor capable of receiving large vessels, and the old military runway, while still physically present, is not maintained for aircraft operations.
The combination of residual contamination, the absence of infrastructure, and the extreme remoteness creates a situation where even motivated researchers struggle to work at the site. Expeditions typically rely on NOAA research vessels and are planned years in advance. Some scientific work at Johnston has shifted toward remote sensing and satellite monitoring, which can track changes in reef structure, vegetation cover, and water temperature without requiring a physical presence on the ground. But certain questions, like the status of invasive ant populations or the bioaccumulation of contaminants in resident wildlife, still require boots on the coral.
For most people, Johnston Atoll will remain an abstraction: a dot on a Pacific chart, a footnote in Cold War history, and an unusual case study in what happens when a military installation is simply switched off and returned to the ocean. The seabirds and the ants and the slowly recovering coral do not know or care about the atoll’s geopolitical history. They are working out the future of the place on their own terms, which is perhaps the most honest form of land management Johnston has ever experienced.