The U.S. has calculated that it will spend about $10 million a year over the next few years, to remove World War II era bombs and shells on Guam, as new bases for troops are constructed. The United States is in the process of transferring 8,600 marines from Okinawa to Guam. In addition, new facilities for warplanes and visiting warships are being built. All this is to be completed in the next four years.
The bomb disposal teams on Guam are still called out 4-5 times a week, 65 years after World War II ended. It's worse in Europe, where hundreds of World War II explosives are unearthed each year in Germany alone. Usually there are no casualties, as bomb disposal technicians are well trained and get lots of practice. But the fuzes that did not go off in the 1940s, are now getting old and more prone to detonation while being disabled. Detonating bombs in place is often expensive, because it means evacuating lots of people, and exposing homes and businesses to bomb damage.
Its not just aircraft bombs. Most of the explosives unearthed are smaller items like grenades, mortar shells, rockets and mines. Many bombs, artillery and mortar shells (over ten percent, for some manufacturers) did not explode when they were supposed to, but just buried themselves into the ground. These shells are still full of explosives, and often have a fuze that, while defective, is often still capable of going off if disturbed. Other munitions were left in bunkers, or elsewhere on the battlefield, and got buried and lost. Most of these lost munitions eventually get found by farmers, or anyone digging up the ground for construction. Most large cities, Europe and the Pacific, that were heavily bombed cities during World War II, still suffer from construction crews unearthing unexploded bombs.
The problem goes back farther than World War II. Unexploded munitions from the World War I (which ended in 1918), and the American Civil War (which ended in 1865), are still showing up, and some of them are still deadly. Currently, over a thousand World War II munitions are discovered each year in Europe.
Guam was heavily fought over during World War II, and the entire island is considered a "battleground" for historical purposes. Guam is about 7,000 kilometers west of Hawaii. The civilian population is 173,000 and military facilities include a major U.S. Air Force base, a port for U.S. naval forces in the central Pacific, and a base for SOCOM (Special Operations Command). The air force bases heavy bombers (B-52s and B-2s), fighters, tankers and Global Hawk UAVs. The navy has maritime patrol aircraft. The U.S. Coast Guard also has a base, as Guam is an American territory, and all residents are U.S. citizens. The army has several support facilities there. Aside from the military, the main economic activity is tourism, especially for visitors from East Asia.
Military facilities are being refurbished and expanded at great expense (over $8 billion), a project that will continue for another four years. But first, you have to get all the unexploded World War II munitions out of the way.