Fallout shelter A fallout shelter is an enclosed space specially designed to protect occupants from radioactive debris or fallout resulting from a nuclear explosion . Many such shelters were constructed as civil defense measures during the Cold War . During a nuclear explosion , matter vaporized in the resulting fireball is exposed to neutrons from the explosion , absorbs them , and becomes radioactive . When this material condenses in the rain , it forms dust and light sandy materials that resembles ground pumice . The fallout emits alpha and beta particle s , as well as gamma rays . Much of this highly radioactive material then falls to earth , subjecting anything within the line of sight to radiation , a significant hazard . A fallout shelter is designed to allow its occupants to minimize exposure to harmful fallout until radioactivity has decayed to a safer level . Although many shelters still exist , some even being used as museums , virtually all fallout shelters have been decommissioned since the fall of the Soviet Union in 1991 . History . During the Cold War , many countries built fallout shelters for high - ranking government officials and crucial military facilities , such as Project Greek Island and Cheyenne Mountain in the United States and Canada ' s Emergency Government Headquarters . Plans were made , however , to use existing buildings with sturdy below - ground - level basements as makeshift fallout shelters . These buildings were usually placard ed with the yellow and black trefoil sign . The National Emergency Alarm Repeater ( N . E . A . R . ) program was developed in 1956 during the Cold War to supplement the existing siren warning systems and radio broadcasts in the event of a nuclear attack . The N . E . A . R . civilian alarm device was engineered and tested but the program was not viable and went defunct about 1966 . In the U . S . in September 1961 , under the direction of Steuart L . Pittman , the federal government started the Community Fallout Shelter Program . A letter from President Kennedy advising the use of fallout shelters appeared in the September 1961 issue of " Life " magazine . In November 1961 in " Fortune " magazine , an article by Gilbert Burck appeared that outlined the plans of Nelson Rockefeller , Edward Teller , Herman Kahn , and Chet Holifield for an enormous network of concrete lined underground fallout shelters throughout the United States sufficient to shelter millions of people to serve as a refuge in case of nuclear war . American fallout shelters in the early 1960s were sometimes funded in conjunction with funding for other federal programs , such as urban renewal projects of the Federal Housing Authority , examples being Barrington Plaza , and other development projects of Los Angeles County Civil Defense and Disaster Commission er , Louis Lesser , and were designed for large numbers of citizens . Switzerland built an extensive network of fallout shelters , not only through extra hardening of government buildings such as schools , but also through a building regulation that ensured that all residential building built after 1978 contained a nuclear shelter able to withstand a blast from a 12 megaton explosion at a distance of 700 metres . In addition , the Swiss government maintains large communal shelters ( including the Sonnenberg Tunnel ) stocked with over four months of food and fuel . The reference Nuclear War Survival Skills declared that , as of 1986 , " Switzerland has the best civil defense system , one that already includes blast shelters for over 85 percent of all its citizens . " Similar projects have been undertaken in Finland , which requires all buildings with area over 600 m² to have an NBC shelter , and Norway , which requires all buildings with an area over 1000 m² to have a shelter . The former Soviet Union and other Eastern Bloc countries often designed their underground mass - transit and subway tunnels to serve as bomb and fallout shelters in the event of an attack . Interest in fallout shelters has largely dropped , as the perceived threat of global nuclear war reduced after the end of the Cold War . In Switzerland , most residential shelters are no longer stocked with the food and water required for prolonged habitation and a large number have been converted by the owners to other uses ( e . g . , wine cellar s , ski rooms , gyms ) . These shelters also provide a haven from natural disasters such as tornadoes and hurricanes , although Switzerland is rarely subject to such natural phenomena . Details of shelter construction . Shielding . A basic fallout shelter consists of shields that reduce gamma ray exposure by a factor of 1000 . The required shielding can be accomplished with 10 times the thickness of any quantity of material capable of cutting gamma ray exposure in half . Shields that reduce gamma ray intensity by 50 % ( 1 / 2 ) include 1 cm ( 0 . 4 inch ) of lead , 6 cm ( 2 . 4 inches ) of concrete , 9 cm ( 3 . 6 inches ) of packed earth or 150 m ( 500 ft ) of air . When multiple thicknesses are built , the shielding multiplies . Thus , a practical fallout shield is ten halving - thicknesses of packed earth , reducing gamma rays by approximately 1024 times ( 2 ) . Usually , an expedient purpose - built fallout shelter is a trench ; with a strong roof buried by c . 1 m ( 3 ft ) of earth . The two ends of the trench have ramps or entrances at right angles to the trench , so that gamma rays cannot enter ( they can travel only in straight lines ) . To make the overburden waterproof ( in case of rain ) , a plastic sheet may be buried a few inches below the surface and held down with rocks or bricks . Blast doors are designed to absorb the shock wave of a nuclear blast , bending and then returning to their original shape . Climate control . Dry earth is a reasonably good thermal insulator , and over several weeks of habitation , a shelter will become dangerously hot . The simplest form of effective fan to cool a shelter is a wide , heavy frame with flaps that swing in the shelter ' s doorway and can be swung from hinges on the ceiling . The flaps open in one direction and close in the other , pumping air . ( This is a Kearny Air Pump , or KAP , named after the inventor , Cresson Kearny ) Unfiltered air is safe , since the most dangerous fallout has the consistency of sand or finely ground pumice . Such large particles are not easily ingested into the soft tissues of the body , so extensive filters are not required . Any exposure to fine dust is far less hazardous than exposure to the fallout outside the shelter . Dust fine enough to pass the entrance will probably pass through the shelter . Some shelters , however , incorporate NBC - filters for additional protection . Locations . Effective public shelters can be the middle floors of some tall buildings or parking structures , or below ground level in most buildings with more than 10 floors . The thickness of the upper floors must form an effective shield , and the windows of the sheltered area must not view fallout - covered ground that is closer than 1 . 5 km ( 1 mi ) . One of Switzerland ' s solutions is to utilise road tunnels passing through the mountains ; with some of these shelters being able to protect tens of thousands . Fallout shelters are not always underground . Above ground buildings with walls and roofs dense enough to afford a meaningful protection factor can be used as a fallout shelter . Contents . A battery - powered radio may be helpful to get reports of fallout patterns and clearance . However , radio and other electronic equipment may be disabled by electromagnetic pulse . For example , even at the height of the cold war , EMP protection had been completed for only 125 of the approximately 2 , 771 radio stations in the United States Emergency Broadcast System . Also , only 110 of 3 , 000 existing Emergency Operating Centers had been protected against EMP effects . The Emergency Broadcast System has since been supplanted in the United States by the Emergency Alert System . The reference " Nuclear War Survival Skills " includes the following supplies in a list of " Minimum Pre - Crisis Preparations " : one or more shovels , a pick , a bow - saw with an extra blade , a hammer , and 4 - mil polyethylene film ( also any necessary nails , wire , etc . ) ; a homemade shelter - ventilating pump ( a KAP ) ; large containers for water ; a plastic bottle of sodium hypochlorite bleach ; one or two KFM s and the knowledge to operate them ; at least a 2 - week supply of compact , nonperishable food ; an efficient portable stove ; wooden matches in a waterproof container ; essential containers and utensils for storing , transporting , and cooking food ; a hose - vented 5 - gallon can , with heavy plastic bags for liners , for use as a toilet ; tampons ; insect screen and fly bait ; any special medications needed by family members ; Pure potassium iodide , a 2 - oz bottle , and a medicine - dropper ; A first - aid kit and a tube of antibiotic ointment ; long - burning candles ( with small wicks ) sufficient for at least 14 nights ; an oil lamp ; a flashlight and extra batteries ; and a transistor radio with extra batteries and a metal box to protect it from EMP . Inhabitants should have water on hand , 1 - 2 gallons per person per day . Water stored in bulk containers requires less space than water stored in smaller bottles . Kearny Fallout Meter . Commercially made Geiger counters are expensive and require frequent calibration . It is possible to construct an electrometer - type radiation meter called the Kearny Fallout Meter , which does not require batteries or professional calibration , from properly - scaled plans with just a coffee can or pail , gypsum board , monofilament fishing line , and aluminum foil . Plans are freely available in the public domain in the reference Nuclear War Survival Skills by Cresson Kearny . Use . Inhabitants should plan to remain sheltered for at least two weeks ( with an hour out at the end of the first week – see Swiss Civil Defense guidelines ( which was once part of Swiss Zivilschutz ) ) , then work outside for gradually increasing amounts of time , to four hours a day at three weeks . The normal work is to sweep or wash fallout into shallow trenches to decontaminate the area . They should sleep in a shelter for several months . Evacuation at three weeks is recommended by official authorities . If available , inhabitants may take potassium iodide at the rate of 130 mg / day per adult ( 65 mg / day per child ) as an additional measure to protect the thyroid gland from the uptake of dangerous radioactive iodine , a component of most fallout and reactor waste . Different types of radiation emitted by fallout . Alpha ( α ) . In the vast majority of accidents , and in all atomic bomb blasts , the threat due to beta and gamma emitters is greater than that posed by the alpha emitters in the fallout . Alpha particles are identical to a helium - 4 nucleus ( two protons and two neutrons ) , and travel at speeds in excess of 5 % of the speed of light . Alpha particles have little penetrating power ; most cannot penetrate through human skin . Avoiding direct exposure with fallout particles will prevent injury from alpha radiation . Beta ( β ) . Beta radiation consists of particles ( high - speed electrons ) given off by some fallout . Most beta particles cannot penetrate more than about 10 feet ( 3 m ) of air or about inch ( 3 mm ) of water , wood , or human body tissue ; or a sheet of aluminum foil . Avoiding direct exposure with fallout particles will prevent most injuries from beta radiation . The primary dangers associated with beta radiation are internal exposure from ingested fallout particles and beta burns from fallout particles no more than a few days old . Beta burn s can result from contact with highly radioactive particles on bare skin ; ordinary clothing separating fresh fallout particles from the skin can provide significant shielding . Gamma ( γ ) . Gamma radiation penetrates further through matter than alpha or beta radiation . Most of the design of a typical fallout shelter is intended to protect against gamma rays . Gamma rays are better absorbed by materials with high atomic numbers and high density , although neither effect is important compared to the total mass per area in the path of the gamma ray . Thus , lead is only modestly better as a gamma shield than an equal mass of another shielding material such as aluminum , concrete , water or soil . Some gamma radiation from fallout will penetrate into even the best shelters . However , the radiation dose received while inside a shelter can be significantly reduced with proper shielding . Ten halving thicknesses of a given material can reduce gamma exposure to less than of unshielded exposure . Weapons versus nuclear accident fallout . The bulk of the radioactivity in nuclear accident fallout is more long - lived than that in weapons fallout . A good table of the nuclide s , such as that provided by the Korean Atomic Energy Research Institute , includes the fission yields of the different nuclides . From this data it is possible to calculate the isotopic mixture in the fallout ( due to fission products in bomb fallout ) . Other matters and simple improvements . While a person ' s home may not be a purpose - made shelter , it could be thought of as one if measures are taken to improve the degree of fallout protection . Measures to lower the beta dose . The main threat of beta radiation exposure comes from " hot particle s " in contact with or close to the skin of a person . Also , swallowed or inhaled hot particles could cause beta burn s . As it is important to avoid bringing hot particles into the shelter , one option is to remove one ' s outer clothing , or follow other decontamination procedures , on entry . Fallout particles will cease to be radioactive enough to cause beta burns within a few days following a nuclear explosion . The danger of gamma radiation will persist for far longer than the threat of beta burns in areas with heavy fallout exposure . Measures to lower the gamma dose rate . The gamma dose rate due to the contamination brought into the shelter on the clothing of a person is likely to be small ( by wartime standards ) compared to gamma radiation that penetrates through the walls of the shelter . The following measures can be taken to reduce the amount of gamma radiation entering the shelter : Fallout shelters in popular culture . Fallout shelters feature prominently in the Robert A . Heinlein novel " Farnham ' s Freehold " ( Heinlein built a fairly extensive shelter near his home in Colorado Springs in 1963 ) , " Pulling Through " by Dean Ing , " A Canticle for Leibowitz " by Walter M . Miller and " Earth " by David Brin . The " Twilight Zone " episode " The Shelter " , from a Rod Serling script , deals with the consequences of actually using a shelter . In the " Only Fools and Horses " episode " The Russians are Coming " , Derek Trotter buys a lead fallout shelter , then decides to construct it in fear of an impending nuclear war caused by the Soviet Union ( who were still active during the episode ' s creation ) . The 1982 album " The Nightfly " by Donald Fagen features a song , ' New Frontier ' , about an early - 1960s teenager enticing his girlfriend into spending a romantic weekend with him in his family ' s backyard fallout shelter . In 1999 the film " Blast from the Past " was released . It is a romantic comedy film about a nuclear physicist , his wife , and son that enter a well - equipped , spacious fallout shelter during the 1962 Cuban Missile Crisis . They do not emerge until 35 years later , in 1997 . The film shows their reaction to contemporary society . In book 11 of the " Cirque du Freak " book series , Darren and Harkat must go into an alternate world . They then find a fallout shelter with post cards on the refrigerator from the late 1940s and realized that they had gone forward in time . The " Fallout " series of computer games depicts the remains of human civilization after an immensely destructive nuclear war ; the United States of America had built underground vaults that were advertised to protect the general population against a nuclear attack , but were , in fact , grand social experiments that did little to protect their inhabitants . " Paranoia " , a role - playing game , takes place in a form of fallout shelter , which has become ruled by an insane computer . The " Metro 2033 " book series by Russian author Dmitry Glukhovsky depicts survivors ' life in the subway systems below Moscow and Saint - Petersburg after a global nuclear holocaust . Cormac McCarthy ' s book " The Road " and the accompanying movie has its main characters finding a shelter ( bomb or fallout ) with uneaten rations . See also . Nation specific : General : Publications :