Enewetak Atoll

Enewetak Atoll is a vast coral atoll located in the Pacific Ocean.

It consists of 40 islands that form a ring around a deep central lagoon. The atoll is part of the Ralik Chain within the Marshall Islands. It sits west of Bikini Atoll and is the second-westernmost atoll in its chain. As of 2021, the atoll is home to 296 people. These residents form a legislative district of the Marshall Islands. The land is very low, with a mean elevation of only 2 meters above sea level.

The physical structure of the atoll has a deep geological history. It formed on top of a large seamount, which is an underwater mountain. This seamount was created during the late Cretaceous period. The mountain is composed of basalt, a type of volcanic rock. Today, the seamount sits mostly below sea level. This is not due to erosion of the rock. Instead, the entire region has undergone a process called subsidence. This means the seafloor and the mountain have slowly sunk over time.

Human history on the atoll began around 1,000 B.C. Austronesian islanders were the first people to settle the islands. European contact began in 1529 with the Spanish explorer Álvaro de Saavedra Cerón. He named the islands "Los Jardines," or The Gardens. In 1794, British sailors called the area "Brown's Range." This name later led the Japanese to call it Brown Atoll. The islands were part of a German colony starting in 1885. In 1914, the Imperial Japanese Navy captured the atoll during World War I.

World War II brought intense conflict to the atoll. In November 1942, the Japanese built an airfield on Engebi Island. They used it to refuel planes traveling between Truk and eastern islands. In early 1944, the Japanese assigned the 1st Amphibious Brigade to defend the atoll. This brigade included about 2,586 men. However, they could not finish their fortifications before the American attack in February 1944.

The Americans captured the atoll during a five-day operation. Much of the fighting occurred on Engebi Islet and Parry Island. Following the battle, the United States established Naval Base Eniwetok. The lagoon became a massive anchorage for ships. During July 1944, the daily average of ships in the lagoon reached 488.

After the war, the United States used the atoll for nuclear weapons testing. This occurred between 1948 and 1958 as part of the Pacific Proving Grounds. A total of 43 nuclear tests were conducted there. One major event was the Ivy Mike test in late 1952. This was the first hydrogen bomb test. The explosion was so powerful that it vaporized the islet of Elugelab. The test even created two new chemical elements: Fermium and Einsteinium. During this era, the U.S. government often evacuated local residents from their homes.

To manage radioactive waste, the military began a massive cleanup project. Between 1977 and 1980, they worked to decontaminate the islands. They mixed more than 61,000 cubic meters of contaminated soil and debris with Portland cement. This mixture was buried in a large crater on Runit Island. This crater was created by the "Cactus" nuclear test in 1958.

To cover the waste, engineers built the Runit Dome. This structure is made of 358 concrete panels, each 1.2 meters thick. The entire cleanup project cost $239 million. There are modern concerns that rising sea levels could breach the dome.

Today, Enewetak Atoll is part of the independent nation of the Marshall Islands. The relationship between the U.S. and the Marshall Islands is guided by a formal agreement. This includes the Compact of Free Association, ratified in 1986. A special fund was created to help people harmed by nuclear testing. A Marshall Islands Nuclear Claims Tribunal was also established to manage these claims. The atoll remains a place of significant scientific and historical importance. Experts project much of the atoll may be fit for habitation by 2026 or 2027.