From the end of World War II until the early 1990s, the world faced a period of heightened international tension and competition called the Cold War. The United States and the non-communist world faced extraordinary circumstances, which they saw as a threat to world peace, democracy, and security:
The Federal Civil Defense Administration The federal government responded to heightened public anxiety by creating the Federal Civil Defense Administration (FCDA), later called the Office of Civil Defense, to instruct the public about how to prepare for a nuclear assault. The Eisenhower administration distributed information to educate Americans about how they could protect themselves. Survival literature was written primarily for a suburban audience, since it was assumed that cities would be targets and most urban dwellers would not survive. Officials at the FCDA stated that if people were educated and prepared for a nuclear attack, they could survive an atomic bomb and avoid the wholesale death and destruction that had occurred at Hiroshima and Nagasaki. What is a fallout shelter and how were they built? A fallout shelter is a civil defense measure intended to reduce casualties in a nuclear war. It is designed to allow those inside it to avoid exposure to harmful fallout from a nuclear blast and its likely aftermath of radiation until radioactivity has dropped to a safer level. A basic fallout shelter consists of shielding that reduces gamma-ray exposure. Since the most dangerous fallout has the consistency of sand or finely ground pumice, a successful fallout shelter need not filter fine dust from air. The fine dust both emits relatively little radiation and does not settle to the earth, where the fallout shelter exists. Concrete, bricks, earth, and sand are some of the materials that are dense or heavy enough to provide fallout protection. Concrete was the favored building material of fallout shelters, with walls at least 12 inches thick. The required shielding could be accomplished with 10 times the amount of any quantity of material capable of cutting gamma-ray effects in half. Shields that reduce gamma ray intensity by 50 percent include 0.4 inches of lead, 2.4 inches of concrete, 3.6 inches of packed dirt or 500 feet of air. When multiple thicknesses are built, the shielding multiplies. The federal government recommended that fallout shelters be placed in a basement or buried in the backyard. The idea was to get as much mass as possible between survivors, the detonation, and its after-effects. Shelter types were: expedience, personal or family, community, multipurpose, and hidden. Usually, an expedience fallout shelter was a trench with a strong roof buried under three feet of earth. The two ends of the trench had ramps or entrances at right angles to the trench so that gamma rays could not enter. To make the roof waterproof in case of rain, a plastic sheet was buried a few inches below the surface and held down with rocks or bricks. A fallout shelter built in the corner of a basement was the least expensive type, and it supposedly offered substantial protection. In many plans, concrete blocks provided the walls. An open doorway and vents near the floor provided ventilation. The shelter's entrance was constructed with a sharp turn to reduce radiation intensity. According to civil defense authorities, a concrete block basement shelter could be built as a do-it-yourself project for $150 to $200 at the time. Exactly how much protection it actually afforded was an open question. Civil Defense suggested plans for such a structure in basements, converted cisterns, or other below-ground sites. Even four feet of earth or a couple of feet of concrete would reduce the level of gamma-ray radiation that would reach the family in an underground shelter. Ventilation in the shelter was provided by a hand-cranked blower attached by a pipe to a filter mechanism on the surface. By turning the crank, the shelter would be ventilated with fresh air filtered to keep out radioactive particles. More elaborate plans suggested installing an electrical generator to provide all the comforts of home. Some custom built-in-place shelters were described as buried several feet underground somewhere in one's yard, with either tunnel access from a basement or a double-entry area through hatches in the yard. Many shelters built during the 1960s were not designed well. They might block radiation, but were not built to hold people long enough for the threat to dissipate, because they lacked air-handling and waste-disposal systems. Earth is an excellent thermal insulator, and over several weeks of habitation, a shelter temperature would rise merely by the occupants' body heat. Without good ventilation, the occupants could suffer heat exhaustion or suffocation. It was recommended that inhabitants plan to remain sheltered full time for at least two weeks following a nuclear blast, then work outside for gradually increasing amounts of time, to four hours a day at three weeks. Typical work supposedly was to sweep or wash fallout into shallow trenches to decontaminate the area. It was recommended that occupants sleep in a shelter for several months. One of the few government shelters actually built from scratch was the Los Altos, California municipal fallout shelter, constructed in 1962. The Los Altos facility was 25-by-48-feet, equipped to sleep at least 96 persons, and rested about 15 feet below the surface. It was maintained by the city of Los Altos for years. Most shelters were smaller, designed to protect the family, and placed in the back yard. During that era, the government surveyed tens of thousands of large buildings in cities, and designated some of them as shelters, stocking them with canned water and food. Depending on the amount of money that one was prepared to spend, many items of equipment and supplies were recommended. They included a battery-powered radio, lanterns, sleeping bags and cots, Geiger counter, chemical toilet and waste holding tanks/waste disposal bags, heating system and fuel tank, air circulation system or air filtering systems, or bottled air, electrical generator, firearms (to discourage intruders), and communications hardware. Recommended supplies included a variety of canned goods or foodstuffs, bottled drinking water or water storage drums, first-aid kits, reading material, recreational materials, cleaning supplies, extra clothing, and writing materials. What is nuclear fallout? Nuclear fallout is radioactive dust created when a nuclear weapon detonates. The explosion vaporizes any material within its fireball. Much of that material is exposed to neutrons from the explosion, absorbs them, and becomes radioactive. When that material condenses in the cloud, it forms dust and light sandy material that resembles ground pumice. The fallout emits gamma rays. Much of that highly radioactive material then falls to earth, subjecting anything to gamma radiation — a significant hazard. Gamma particles are responsible for the great majority of illnesses associated with nuclear explosions. Too much direct contact with gamma rays can injure or kill, and cause such subsequent health problems as cancer. Gamma particles emit most of their radiation quickly, and during the first few hours and days following an attack, they should be avoided as much as possible. Why were fallout shelters built? During the Cold War, a period of great international tension, Americans felt threatened by the possibility of a nuclear war and sought ways to survive an attack. Fallout shelters entered the American consciousness and vocabulary in 1949 when President Harry Truman made it publicly known that the Soviet Union had detonated their first atomic bomb, ushering in an era when the United States faced the fact that it had lost its nuclear autonomy. That introduced the world to the real possibility of nuclear war between the two superpowers. Long-range bombers and intercontinental ballistic missiles made that threat real. In the late 1940s and 1950s, government officials believed that most urban dwellers could escape nuclear attacks by evacuating from their cities. Confident that they would have enough warning time, most communities prepared evacuation plans. Fear of nuclear war grew throughout the 1950s with the development of the hydrogen bomb by both the United States and the Soviet Union. Early in the Atomic Age, the United States government concluded that it could not shelter every American citizen from a nuclear war. The Eisenhower administration expressed little interest in shelters until 1957, when the Gaither Report was released in the U.S. The report was the culmination of an effort to assess the relative nuclear capability and civil defense efforts of the United States and the Soviet Union. The report concluded that the United States would soon be surpassed in all categories of nuclear weaponry and that civil defense preparations in the U.S.S.R. were well ahead of American efforts. Public response to the report was an upsurge in interest about fallout shelters. By the late 1950s, officials of the Eisenhower administration believed that they had a realistic idea of how difficult it would be to survive a nuclear bomb blast, and was actively promoting the construction of fallout shelters as part of the civil defense program. Plans were drawn up. From 1958 onward, the Office of Civil Defense not only promoted home shelters but also published a collection of manuals that showed Americans how to build home shelters. During the Kennedy administration, America saw a rise in international tensions, and Kennedy's advocacy of shelters as part of the American response to two anxious standoffs with Moscow. The first was in 1961 when the Soviets built the Berlin Wall and the second was the Cuban Missile Crisis a year later. President Kennedy, believing the lives of families not directly hit in a nuclear attack could still be saved if they could take shelter, endorsed the construction of fallout shelters. In the summer of 1961, Kennedy asked Congress for more than $100 million for public fallout shelters and home-based imminent nuclear danger alarm systems. At the time of the Berlin Wall, a majority of Americans believed World War III would occur within five years. Anxiety in the United States rose after Soviet premiere Nikita Khrushchev announced that the Soviet Union would resume testing atomic weapons at once, ending a three-year moratorium. By 1962, most officials began to realize that evacuation plans were unrealistic, owing to the large number of people who would have to evacuate, and placed a greater importance on public shelters instead. American's uncertainties about the bomb quieted during the mid-1960s. As arms-control talks and a limited nuclear test ban proceeded, tensions eased. Plans for building additional public shelters were postponed. Shelters were converted into wine cellars, mushroom gardens, recreation rooms, or storage areas. The remaining public underground quarters are relics of the Cold War era.