What Is Needed to Survive and Recover from a Terrorist Nuclear Explosion

Walmer E. Strope



  It may seem strange to encounter an essay on—yes—civil defense as we near the end of the first decade of the twenty-first century  Two things have come to my attention that together have motivated me to put pen to paper.

  The first thing that has impressed me is a presentation made by Mr. Kirk Paradise at the Doctors for Disaster Preparedness annual meeting in July 2008. Paradise is the emergency management coordinator for Madison County, Alabama. In his remarks, he noted that in his opinion the Department of Homeland Security had exerted great effort and much federal funds to prepare to deal with possible chemical and biological terrorist attacks. On a scale of zero to ten, he believed he would rate the nationwide readiness to deal with chemical and biological attacks to be a nine. On the other hand, the effort to prepare to deal with a terrorist nuclear attack has been negligible and he would rate the readiness as a one on the same scale.

  This judgment by one in a position to know confirms my observation that the Bush administration and the Congress have “bet the ranch” on our ability to prevent the occurrence of a terrorist nuclear explosion to the extent of neglecting any serious attempt to deal with this threat. Huge efforts have been devoted to searching truck and ship cargo containers at ports of entry. It is a mammoth task made extremely difficult by the tiny emanations that might betray a hidden nuclear device. Many years ago, Dr. Robert Oppenheimer, asked by a congressional committee if there was any device that would detect a hidden bomb, replied, “A screwdriver.”

  The second thing that influenced me was the theme of the successful presidential campaign of Barack Obama. That theme, of course, was “Change,” which could be interpreted in a variety of ways. I didn’t listen to any campaign speeches, only the sound-bites on cable news, so I could have gotten a distorted impression of his intent. But I detected an interest in volunteer activities at the local level, in organized social efforts, in perhaps a revived domestic Peace Corps. If so, civil defense in the form of preparing to survive and recover from a terrorist nuclear explosion is a mission that can elicit huge numbers of volunteers to participate. The history of civil defense is proof of this.


Chapter 1

The Shape of the Threat

What would a terrorist nuclear attack look like? Perhaps only some members of the terrorist group have a good estimate. What we do know is that the terrorist threat is wholly different from the threat that we faced during the Cold War. Back then, in the 1970s and 1980s, a nuclear exchange between the United States and the Soviet Union would have involved the detonation of thousands of multi-megaton warheads throughout the industrial nations of the northern hemisphere. Many distinguished scientists lamented that such an event would mean the end of civilization. Other scientists predicted that the thousands of mushroom clouds and smoke from burning cities would so hide the sun that the planet would freeze up in a “Nuclear Winter.” Although these predictions may be exaggerations, the concept of civil defense—survival and recovery—seemed ludicrous. 

  The terrorist nuclear threat is nothing like the above. For one thing, it most likely will consist of a single nuclear explosion, as is suggested by the title of this paper. The only ways that a terrorist group such as Al Qaeda can obtain a nuclear device is to build one surreptitiously or obtain one from a willing supplier. Building a nuclear weapon requires not only an adequate supply of fissile material but also nonnuclear parts and facilities for precision machining and the like. North Korea had all that but when they tested their bomb it did not work. The mass media has saluted North Korea as a new member of the “nuclear club” of nations possessing nuclear weapons but all we know is that North Korean weapons don’t work. Al Qaeda probably wouldn’t buy one. 

  Iran also is trying to get a nuclear weapon. “It seems hard to imagine that Iran does not already have them,” says historian Michael Ledeen. “Iranians are not stupid, and they have been at this for a minimum of twenty years in a world where almost all of the major components needed for a nuclear weapon—not to mention old nuclear weapons—are for sale.” But, so far, Iran has not found a willing supplier. We don’t know about Al Qaeda. We do know that Usama bin Laden has said that if he had several nukes he would put one in each of several US cities and attempt to detonate them simultaneously.

  The terrorist threat also is shaped by the size or yield of the nuclear explosion. Most analysts agree that the terrorist nuke will be about the size of those that ended World War II with the bombing of Hiroshima and Nagasaki—15 to 20 kilotons.  The reason for this judgment is that the Los Alamos people used the least amount of fissile material (highly-enriched uranium or plutonium) needed to form a critical mass at the moment of detonation. The amount of fissile material needed is by far the most costly component and most difficult to obtain. Actually, the amount of fissile material used in those very-first nukes was somewhat larger than the minimum needed. When the North Koreans tested their nuclear device, they expected a yield of 10 kilotons. They got virtually no fission yield as the critical mass blew apart before only a tiny portion could engage in a chain reaction.

  Another possible source of a terrorist nuclear weapon is said to be one lost when the Soviet Union dissolved. There are inadequate records for some weapons but these are not high-yield ICBMs but rather battlefield devices with yields around 10 kilotons. If there are such not under Russian control, their possible use by terrorists does not change the shape of the terrorist threat.

  An important aspect of the threat is whether the explosion would be high in the air as it was in the Hiroshima and Nagasaki attacks (an air burst) or on or close to the ground (a surface burst.) There appears to be no advantage to terrorists from attempting to deliver an air burst and several drawbacks. If the terrorist objective is to kill as many Americans as possible, the surface burst is superior, as it threatens to kill by blast, fire and fallout whereas the air burst has only blast and fire. A 10-kiloton surface burst produces a crater 280 feet wide and 65 feet deep. No survivors there, but there were several survivors at Hiroshima’s ground zero, directly under the air burst. 

  A surface burst is the natural location for a concealed terrorist nuclear device and surprise is essential to the terrorist purpose, as it was at 9/11. Lack of warning is central to the terrorist threat and it means that civil defense cannot avoid a grievous loss of life. Even so, civil defense can save most of those who would otherwise die. Do both: try to prevent and be prepared to save.

  The unavoidable deaths and injuries from an surprise attack  will occur not only in the crater and its lip but also from blast and fire out to the 10-psi blast overpressure level, which occurs about 0.4 miles from ground zero. Some people outside and unshielded may be lost out to one mile where the blast overpressure is 2 psi. But outside one mile will be thousands who can be at hazard from the radioactive fallout from a surface burst. Consider the following for a 10-kiloton fission explosion:


   Table 1.   Downwind Extent of Reference Dose-Rate for 10 KT Surface Burst


            Dose Rate                               Distance                                  Max. Width

            r/hr@1 hr                                 miles                                         miles


                1500                                       <1                                            <0.5

                 500                                          3                                             < 1

                 150                                          6                                                1

                  50                                           11                                            <2

                  15                                           25                                              5


  This table, which is adapted from Table 9.90 in The Effects of Nuclear Weapons, Revised Edition, shows some key dimensions of the long ellipses called fallout patterns. Some selected values of the unit-time reference dose rate are shown in the left column, their furthest downwind extent and widest width in the center and right columns. The distance and width in miles is for a uniform wind direction at all altitudes and a uniform wind speed of 15 miles per hour.

  When a 10-kiloton nuclear device explodes, about 20 ounces of radioactive fission products are produced as a very complex mixture of over 200 different isotopes of 36 elements. This radioactivity is swept up with large amounts of crater material into the mushroom cloud. Further mixing and cooling occurs as this material falls gradually  back to earth as fallout. At weapons tests, which is where all the available data have been obtained, the wind direction and speed are never uniform and measurements on the ground occur hours and days after the event. The 20 ounces of radioactive fission products have been being depleted since they were formed in the chain reaction. Their “decay curve” is well known and is used to adjust the measured values to a common reference time; namely, one hour after the explosion. That is the left-hand column above. The location measurements are adjusted in a similar fashion to form the dimensions of the ellipses commonly shown to represent fallout areas. 

 Note that the dimensions in Table 1 do not account for the dynamics of the event. All the dose rates are for one hour after the explosion. Where is the mushroom cloud at one hour? It is 15 miles downwind. In the table we see that the 50 r/hr reference dose rate extends 11 miles. So the fallout event is at 15 miles with a peak of less than 50 r/hr. Moreover, the fallout event is over at all distances less than 15 miles with peak dose rates greater than the one-hour reference dose rate. For example, we might assume that the maximum width occurs at half the full distance of the 50 r/hr reference dose rate, or at 6 miles or less. But fallout occurred there at about 20 minutes after burst when the dose rate was 3 times the reference dose rate or about 150 r/hr. Conversely, peak dose rates beyond 15 miles will be lower than the reference dose rate because the fallout arrives later than one hour after burst. As an example, the extent of the 15 r/hr reference dose rate is shown to be 25 miles but fallout would not arrive until nearly two hours after burst when the peak dose rate would be about 8 r/hr. 

  It will be useful to consider this fallout event in considerable detail. Clouds formed by explosions of these magnitudes (10 to 20 KT) generally rise and form at altitudes of 20,000 to 35,000 feet. This 3-mile vertical dimension typifies such clouds but the horizontal dimension usually continues to spread as the cloud is moved by the wind. There is no good evidence of the degree to which the radioactivity is collocated with the visible cloud but the violent mixing occurs early on when the cloud is like a ball and surely much of the radioactivity is on surface material that is already falling toward earth as the cloud is still rising. 

  Perhaps the fallout event is somewhat like a summer thundershower. One may be able to see it coming. There usually is a smattering of large raindrops in advance of the shower, which rains heavily for ten minutes or so before ceasing. One may be able to see it going away downwind. Or think of a cylinder 3 miles in diameter (the diameter of the cloud) extending from the cloud to the ground, within which the fallout material is descending. If there were no wind, the cloud material would fall within a circle of one and a half mile radius centered on the explosion site. With a uniform 15-mile-an-hour wind, it would require 6 minutes for the leading edge of the cylinder to move the remaining mile and a half to the 3-mile point. Fallout would begin at the 3-mile point at six minutes after the explosion and would persist until 18 minutes after the explosion, at which time the cylinder would have completed its passage of the 3-mile point leaving a deposition of fallout sufficient to measure 500 r/hr at one hour after the explosion. At 18 minutes (the cessation of fallout) a survey meter would have measured 2,000 r/hr. 

  It is useful to recognize that the unit-time reference dose rates in the left-hand column of Table 1 are also a measure of fallout deposition. The effect of radioactive decay has been removed so that the only way that 500 r/hr can be measured at 3 miles and only 50 r/hr at  11 miles is that 10 times as much radioactivity was deposited at 3 miles as was deposited at about 11 miles. One can use this correlation to further explore the lethal fallout threat by comparing the deposition process to the medical effects of fallout radiation shown in Table 2.


Table 2.  Effects of Fallout Radiation on People


            Effects                                                                        Acute Exposure (r)

            Medical Care Not Needed                                                        150


            Some Need Medical Care; Few

            If Any Deaths                                                                          250


            Most Need Medical Care; 50%

            Or More Deaths                                                                      450

 The source of the information in Table 2 is the National Council on Radiation Protection and Measurement. Acute Exposure means during a period of up to a week. Exposure over longer periods is less injurious. If lethal exposure of near certainty is meant, 600 r may be an appropriate acute exposure.

  Returning to the subject of fallout deposition, the amount producing 500 r/hr at 3 miles in Table 1 does not diminish abruptly to the amount producing 50 r/hr at 11 miles. Rather, the physics of the situation suggest that the deposition rate constantly diminishes proportionate to the amount of radioactivity remaining in the cloud. The deposit defined by r/hr at 1 hr is shown in Table 3 for every maximum distance shown in Table 1.

Table 3.  Radiation Exposures in Lethal Areas


Distance (miles)                                              1          3          6          11          25

Deposit (r/hr at 1 hr)                                    1500      500      150        50         15

Mid-Fallout (minutes after explosion)           4          12         24         44         100

Peak Dose Rate (r/hr)                                  20000     3000     450        80          8

Total Dose to 1 hour  (r)                               4800      900      140        20           -

Below the deposit line in Table 3 is shown the mid-point of the fallout arrival and cessation times for the fallout event using the cylinder model. This imaginary cylinder has a 3-mile diameter (the cloud diameter at early times). It moves downwind at 15 miles an hour, depositing fallout falling from the cloud. It takes 4 minutes for the leading edge of the cylinder to travel the mile  from the initial location to the 1-mile point as shown in Table 3. The calculations in the table are based on the midpoint of the 12-minute fallout event. After fallout cessation, people continue to be irradiated by the deposit. One can use Figures 9.16a and 9.20 of the revised edition of the Effects of Nuclear Weapons to determine this exposure. The total unprotected dose during the first hour is shown in the last line of Table 3.It can be seen that lethal doses accrue only within about 3 miles of the explosion.

  It should be noted that all the foregoing dose estimates apply strictly to the centerline of the cylindrical fallout event; that is, the fallout event is a full 12 minutes long and traverses a full 3 miles of fallout deposition. However, chords of a 3-mile circle that are ˝-mile on either side of a diameter are very nearly three miles long (2.84 miles) so a swath of fallout about a mile wide probably is appropriate to these calculations. Nearer the edges of the path, the radiations will be greatly reduced. On the other hand, exposures greatly exceeding the guidelines in Table 2, such as the 900 r at 3 miles, indicate a wide path of lethal deposits.

  What have we learned about the shape of the fallout threat from a terrorist nuclear explosion? First, the extent of lethal levels of fallout is mainly confined to areas where fallout arrives within one hour. That area might be about 5 miles long and 2 miles wide or 10 square miles.  Since the area subject to lethal blast and fire is about one square mile, there may be more than ten times as many people  subject to lethal fallout as are subject to lethal blast and fire. One can also conclude that people in the lethal fallout area must be given very good shelter or directed out of the area within a few minutes after the explosion to avoid fatalities.


Chapter 2

Proposed Basic Structure for Saving Lives

We have concluded that a single nuclear explosion of about 10-kiloton yield is the likely terrorist threat. Nonetheless, we should avoid planning a defense that would only work under these circumstances. The defense should be effective if several explosions should occur and if the explosion were twice as big. It should not assume that the target was downtown or that everyone will be home in bed. The plan should be reasonably flexible.

  At the same time, there are threat characteristics that dominate throughout. They are:

·         The fallout from a surface burst will extend well beyond the region of damage and fires in the downwind direction, threatening death and injury to large numbers of people not otherwise at hazard.

·         The lethal part of the fallout event arrives on the ground during the first hour after the explosion.

·         The lethal exposure to fallout radiation will require up to several hours to occur.

·         The lethal part of the fallout event is only a few miles wide.

·         All of the above are observable only through use of dose-rate survey instruments.

With regard to the last item, it is essential to understand that everyone in or near the fallout event is blind to the radiation without survey instruments. That is why the civil defense program of President John F. Kennedy devoted priority to obtaining a well-maintained well-calibrated measurement capability. From 1964 to 1995, such a measurement capability existed nationwide. Then, in an exuberant celebration of the end of the Cold War and with a desire to collect the “peace dividend,” the Clinton administration cancelled the funding to support maintenance and calibration. The system quickly collapsed. By 2003 only a handful of States had a marginal capability. However, there are some 36 States that are within the 10 and/or 50-mile emergency planning zone (EPZ) for nuclear power reactors.  These States are required to have radiological equipment available for use in case of an emergency at the nuclear power plant.  These States do have a maintenance and calibration capability.  Some of these States still utilize civil defense instruments; however, many of them have persuaded the utilities to provide commercial radiological instruments that are the same as those that are used by the utility. These instruments are too few and in the wrong places and in the wrong hands to be useful in a terrorist nuclear explosion. Acquiring sufficient high-range survey meters is likely to be the most expensive part of dealing with a terrorist nuclear attack.

Countermeasures. The protective actions or countermeasures that could be employed in the region of explosive effects are fire suppression, heavy rescue, light rescue and medical aid. The region within one-half mile of the explosion generally will not be traversable by wheeled vehicles and will emit radiation from materials formed by initial radiation from the explosion. In Japan, the survival rate depended upon whether a person was outdoors or inside a building and if so what type of building. At distances between 0.3 and 0.4 mile from ground zero in Hiroshima (15 KT) the average survival rate was less than 20 percent. Yet in two reinforced-concrete buildings at these distances, almost 90 percent of the nearly 800 occupants survived more than 20 days although some died later from radiation injury. Unshielded people were killed nearly a mile from the explosion while those shielded by adjacent buildings survived. These facts indicate that prompt aid to the damaged area around the terrorist explosion will save great numbers of lives. The control of fires set by the explosion also demands a speedy response.

  In the larger fallout area of the surface burst, two options are available: shelter in nearby buildings or prompt movement out of the fallout area. In general, movement out of the area is feasible if the way out is known and a vehicle is available. Persons in the lethal region of the fallout area will never be more than three miles from the nearest edge of the fallout but will know this only after fallout has occurred. Using an average vehicle speed of 30 miles per hour to account for the likelihood that the streets may not lead directly out, the vehicle would be out in 1/10 hour or six minutes. People in fallout of 500 r/hr (lethal in one hour) would get 50 r and be done with it. People sheltered in buildings having a PF (protection factor) of 10 in the same situation would get less than 50 r in the first hour but be subject to continued but lessening exposure. All must eventually be removed from the fallout area and there is no advantage in shelter stays over eight hours, so the provision of food, water, and sanitary facilities is not necessary. On the other hand, urban areas have a surplus of PF 10 or better shelter space so identifying and marking the best available would be wise. In either case, time is of the essence if lives are to be saved. Table 3 indicates that people 3 miles from the explosion downwind have only about six minutes before fallout arrival.

  Speedy operations are so important that it will be essential to have leadership that is always alert and quick to respond. It also would be desirable that this leadership be available everywhere in the urban area and be intimately knowledgeable about the buildings and streets. Fortunately, there is already in place such a leadership together with most of the needed infrastructure. It is the municipal fire service. The fire service is unique in its devotion to speedy operations. Firefighters brag about going from sound sleep to equipment rolling in less than one minute. As a consequence, other rapid-response missions, such as rescue, ambulance and paramedics, have gravitated to the fire service.

  Fire houses constitute a distributed response resource that is virtually unique. For example, consider Washington, the nation’s seat of government and a prime target for terrorists. There are 33 fire houses in the District of Columbia, one for each engine company. Additionally, sixteen truck (ladder) companies and three heavy-duty rescue squads are located in certain of these fire houses, which are spread over the District’s 69 square miles. On average, each fire house is responsible for a little over two square miles of the city. Across the Potomac River in Arlington County, Virginia, there are 10 fire houses covering 25 square miles or two and a half square miles per fire house. This density of fire houses is typical of that in most cities.

  The fire houses in the District of Columbia are not a uniform distance from each other nor are they each responsible for the same amount of territory; far from it. They are located with concern for the type of construction, its density, and the nature of the streets with respect to speed of access. Firemen assigned to a company are required to become familiar with all these characteristics and to practice access to possible fire sites. The boundaries between fire houses are determined by assigning first response generally to the company that can get there most quickly. Every square foot of the city is assigned to some company for fire service.

  The municipal police service is a first-responder organization like the fire service and has distributed leadership capability in the form of precinct stations but these are not as socially close to the surrounding neighborhood as are fire houses. Moreover, there will be a huge movement control task after a terrorist nuclear explosion with which the police department will be faced including closing off access to the fallout area and preventing crime in vacated neighborhoods. The fire service seems better for civil defense. 

CD Districts. The several-square-mile area surrounding each fire house forms a near ideal basis for organizing to deal with a terrorist nuclear attack. This area has no name in most fire services. I choose to call it a “civil defense district” or “CD district.” Thus, in Washington, there would be 33 CD districts and every square foot of the city would lie in one of these CD districts.

  That last statement requires some modification. To fully utilize all relevant resources, every facility or other entity that provides its own fire service should be a CD district. Many urban military installations have their own fire house as do most airports, refineries, some shipyards, manufacturing plants, hospitals, penal institutions and college campuses. Some of these are privately owned and others are federal or state facilities. All should be CD districts. In Washington, Bolling AFB provides a 34th fire house. Across the Potomac, Reagan National Airport, Fort Myer, and the Pentagon provide others.

   Each CD district must develop two capabilities: (1) to assign its population to the best available shelter and care for them there, and (2) to organize its emergency services into a rescue column to perform emergency operations. It is the latter capability that is emphasized in this chapter. Sheltering is discussed in Chapter 3. The basic rescue column  would consist of the fire house engine, at least one police vehicle, and an EMS (emergency medical services) ambulance van. The precise organization should conform to local capabilities and practice. Using existing routines and procedures that work in fast response situations is a wise practice. In addition to their normal equipment, rescue columns must be provided with dose-rate survey instruments or equivalent. 

  The basic operating instructions for CD districts in event of a very large explosion are to place their people in best available shelter and roll the rescue column toward the explosion. To best describe the operations, it is desirable to introduce the concept of basic operating situations (BOS). They can be summarized as shown here:



Table 4: The Basic Operating Situations




>50 r/hr




0.5-50 r/hr




<0.5 r/hr




Heavy       Moderate   No Damage

Damage     Damage



Note that horizontally are degrees of physical damage from blast and fire. Heavy damage is generally taken as the situations when debris prevents the use of wheeled vehicles. On the vertical are degrees of radiation intensity in terms of observed dose rate. The radiation equivalent of “No Damage” is “Less than 0.5 r/hr (500 mr/hr).” Below this level operations can proceed without regard to fallout radiation. The next level are situations in which the dose rate is somewhere between 0.5 r/hr and 50 r/hr. These are situations that may require dose-limited operations, especially near or at 50 r/hr. The highest level applies to dose rates above 50 r/hr and is generally regarded as a “pin down” situation if in best available shelter. Note also that BOS 3, 6 and 9 can occur only in the lethal fallout area and around the explosion itself.

  Consider again the event of a terrorist nuclear explosion somewhere in the prepared (but unwarned) city. The blast and fire area of a 10 kiloton surface burst is about two miles across with the crater in the center. (The blast area of a 20 kiloton surface burst is about two and a half miles across.) The fire houses are about a mile and a half apart on the average. This means that several fire houses should be able to report BOS (bahss) 4 or BOS 7 almost immediately. In the off chance that the explosion is next door to a fire house, that fire house will be gone as well as most of its CD district. The nearest fire houses in all directions should be more or less undamaged. Their rescue columns should report BOS 4 very quickly. Thus, rescue columns from more distant fire houses will be rolling to reinforce companies reporting BOS 4 or higher rather than eyeballing the cloud.

  Also consider the circle at 3 miles from the explosion. Four or five fire houses should be on or near this circle in various directions. Moreover, their rescue columns should be underway almost immediately, headed toward the damaged area about two miles away. One of these units will report BOS 2 or BOS 3 very quickly, thereby confirming the explosion was nuclear and giving the first indication of the downwind direction. One needs to understand the potential role of fallout shelter in the downwind lethal fallout area in order to consider the lifesaving actions available during the first hour after the explosion.


Chapter 3

Shelter Considerations in a Terrorist Nuclear Attack

  The use of fallout shelter in defense against a terrorist nuclear attack is quite different from its contemplated use during the Cold War. Back then, the threat was fallout from thousands of ICBMs with megaton-yield warheads. The fallout would take hours to fall from stratospheric heights so radioactive decay when on the ground would be much slower than that discussed in Chapter 2 and there would be no nearby fallout-free areas to which shelterees could  go. Consequently, shelter stays were likely to be for a week or more. This created a requirement for stocks of water, food, and sanitary supplies as well as concerns about ventilation of crowded shelters.

  The use of shelter in the present instance is not at all like the above. All the lethal fallout is on the ground within the first hour. Safe fallout-free areas are only a mile or two from the shelters in the lethal areas. The radiation decay at early times is rapid. As will be shown, shelter stays can be a matter of hours for most and as long as two days for a few. There is no need to stock shelter areas with anything nor is it useful to encourage people to take anything with them. The current lists of “things to take” published by the Homeland Security Department are unnecessary and possibly counterproductive. 

Fallout Protection. Protection against radiation from fallout is afforded to some degree by any urban structure. In particular, ordinary buildings have been surveyed for the amount of suitable space having various degrees of protection. That this information was gathered during the Cold War does not lessen its value for use in the war on terrorism. It resides in the National Fallout Shelter Survey (NFSS). Every big city had a copy of its part. (If that has been thrown away, check with the State EMA or the district office of the Corps of Engineers.)

  The amount of protection afforded by some point in a building is measured by its Protection Factor (PF), which is the degree by which the outside dose-rate is reduced when at that point in the building. In the NFSS, the range of PFs is subdivided into Categories as shown in the following table.

Table 5  Protection Factor Categories


                        Categories                                           Range of Protection Factors


0                                                                                                                                10 to 19

1                                                                                                                                20 to 39

2                                                                                                                                40 to 69

3                                                                                                                                70 to 99

4                                                                                                                                100 up


  It will be noted that Category 0 is a peculiar way to label the lowest protection category, as if it was added on after the others had been in use. Actually, marking and stocking PF 100 and up was the initial policy when the survey began. Pilot surveys indicated, however, that there was much Category 4+ shelter space in cities but not much in the suburbs. The policy was then changed to marking and stocking Category 2+ shelter, of which there is much more in the suburbs. Now, there is no marking and stocking program but the Department of Homeland Security has adopted the policy that Category 0+ qualifies as fallout shelter. PF 10 is the low end of Category 0.

Table 6  Total Radiation Exposures in Lethal Areas


Distance (miles)                                              1         3         6         11       25

Deposit (r/hr at 1 hr)                                     1500      500      150      50      15

Total Dose at 1 hour (r)                                  4800     900      140      20        -

Total Dose at 7 hours (r)                                7050     1650    365      95        18

Total Dose at 2 days (r)                                  8550    2150    515      145       33

  Table 6 is an extension of Table 3. The distance, deposit and “Total Dose at 1 hour” lines are identical with those in Table 3. The last two lines extend the total dose to stays of 7 hours and two days. These doses may be compared with the medical consequences shown in Table 2. It can be seen that consequences approximating 50 percent deaths extend to six miles from the explosion.  

  Consider people in PF 10 shelter throughout the event. Their exposure would be one-tenth the doses shown in Table 6. In the next-to-worst case—3 miles from the explosion—the doses would be 90 r at 1 hour, 165 r at 7 hours and 215 r at the end of two days. None of these doses is lethal although exposure until 7 hours or later would introduce a requirement for medical care. PF 10 is not good enough for the worst case, which is at the edge of the damage area. But note that Category 2 shelter (PF 40-69) would decrease these in-shelter doses to about 120 r at 1 hour, 175 r at 7 hours and 214 r at two days. These are nonlethal exposures and use of Category 4 shelter would reduce them even further.

  We have postulated CD Districts based on fire houses and their surrounds. These districts will generally have an area of two to three square miles and an average population of 25,000 persons. These people are not necessarily residents of the CD District. Those who live and work in the same square mile of a city are a minority. Nonetheless, there are residential neighborhoods as well as business centers and many CD Districts will be primarily one or the other. The fire company that is the nerve center of the district is the best source of information on the buildings in the district, their construction and equipment, and their use or occupancy.

  There are only two areas in ordinary buildings that qualify as shelter areas: basements and the hallways on middle floors in tall buildings, Table 7. drawn from Effects of Nuclear Weapons, Revised Version, gives some details. In this table, multistory buildings are those having 3 to 10 stories and high-rise buildings are those with more than 10 stories.

                                             Table 7  Protection Factors in Large Buildings

                                    Shelter Space                                                         PF Range

Sub-basements of multistory or high-rise buildings                                     1000 or more


Basements without exposed walls of multistory masonry buildings                 250 to 1000

Central areas of upper floors excluding top 3 floors of high-rise

buildings with heavy floors and exterior walls


Central areas of basements with partially exposed walls in multi-                   50 to 250

story buildings

Central areas of upper floors excluding top floor of multistory

buildings with heavy floors and exterior walls


Central areas of upper floors excluding top floor of multistory                        10 to 50

buildings with light floors and exterior walls


It is clear that there is a lot of very good fallout shelter in cities. Table 7 is not complete by any means. Subway entrances, underground garages, tunnels and pedestrian malls are some of the very good shelter areas that might be added. Of equal importance are Category 2+ shelter in row houses that are commonly residences, shops, and restaurants, including 3-story brownstones and most two-story townhouses except for those on the end. Row houses often are narrow across the front and quite deep so that a large part of the periphery is shielded by the adjoining houses. The main source of fallout radiation is fallout on the roof, so shelter is on the first floor or in the basement if such exists. Two-story houses with a full basement have Category 1 shelter in the basement. The basement of a one-story building has Category 0. Such buildings without a basement have PF 2-4 only. During the planning phase a volunteer crew in each CD district must match the day and night residents to the best available shelter where they are, using written guidance after a short training course.  

 The CD District mission phrase, “to assign . . . shelter,” is terribly constrained by the need for quick sheltering if the district should end up only two or three miles in the downwind direction from the explosion. Only one or two districts can end up in this situation but all must plan for the contingency. The best sheltering situation is for those who live or work in multistory or high-rise buildings (or are just walking by.) Those on the ground floor simply take refuge in the basement and those on upper floors leave their windowed offices and take refuge in the central hallways. Someone at the fire house or other district organization needs to make sure that the shelter capacity is adequate for the highest occupancy and to contact the building owner if some form of use agreement is needed. Signage like that already in hallways for fire safety could provide instruction but it would be better to have volunteer occupants who can alert and lead the others. Such volunteers not only can help assure proper sheltering but also organize the leave-taking out of the fallout area at the proper time. Many large buildings have a security force that provide 24/7 coverage. They should become the kernel of shelter preparedness. If there are no security personnel, the building engineer and janitor service will do. 

  The NFSS data do not include small residential buildings but census tract data can provide much useful information. Census tracts are small areas of the city for which census results are summarized. For example, Arlington County, which is the part of the District of Columbia that was given back to Virginia and is one of the smallest counties in the country, has 10 fire houses and 38 census tracts in its 25 square miles. Each proposed CD District in Arlington County would have about four census tracts although the boundaries are unlikely to be congruent. Among the tract data published, there is a table entitled, “Structural, Equipment, and Financial Characteristics of Housing Units.” The tract numbers are arrayed across the top of this table. In the body of the table are numbers of housing units, not houses, but the very first set of data are the number of housing units in structures, ranging from single-family to structures containing more than 50 units. Other data sets in the table tell one how many units are in houses with basements and how many automobiles are possessed by occupants of housing units. The fire company has a detailed knowledge of the structures in its service area but not necessarily whether the people having cars have room to take with them those having none in tracts with little fallout shelter.

  There will be areas in any large city with poor shelter against fallout. Such areas are more likely to be business occupancies rather than residential ones, like warehouses  constructed with light steel framing and sheet metal siding and on concrete slabs. The only protective action may be to drive away from the explosion in whatever vehicles are available, including delivery trucks and eighteen wheelers.

   There are many types of facilities that pose special problems either in sheltering or evacuation: schools, hospitals, nursing homes, penal institutions, waterfront piers and wharfs, mental institutions, military facilities not having their own fire service, and bus and train marshalling yards, to name a few. Solutions to many of the specialized problems inherent in these facilities can be found in natural disaster records or Cold War crisis relocation plans. For example, it has been found that bedridden patients can be transported in any van with rear doors or even pickup trucks. When these sorts of facilities are encountered by the CD district planners, the citywide planning staff should be consulted. Sheltering solutions for special facilities are best addressed on a citywide basis. 

  Sheltering should be the fundamental response to a terrorist nuclear explosion. The underlying reason is that the proportion of the urban population without a private vehicle handy for evacuation is far too high. Also, every large city is on a river or bay that limits access to bridges or tunnels so as to make fast movement away from the hazard a traffic nightmare. Since most of this attempt at flight turns out to be unnecessary once the fallout area is known, sheltering in place is less disruptive when deemed unnecessary.


Chapter 4

The Big Picture

  The significant conclusions that should be drawn from this brief tutorial are that in a terrorist nuclear explosion bad things are going to happen fast and it is most likely but not always that  taking refuge in the best available shelter is the best survival measure. It is time to look at the “big picture.”

  To begin with, forget about the Department of Homeland Security and the Federal Emergency Management Agency, even if the explosion is in Washington. The bad things will have happened before they can do whatever it is that they do in an actual emergency. The same goes for the State Emergency Management staffs. The state and federal apparatus can help the cities get ready and stay ready and they can provide support in the weeks and months afterwards but like 9/11 the bad things happen so fast that only the fire service is able to do something. 

  The appropriate place to see the big picture is the big-city emergency operating center (EOC) with which every city is equipped, courtesy of John F. Kennedy’s Cold War civil defense program. If one postulates CD districts based on fire houses, each with its mission preparations accomplished, the EOC will know that all surviving districts will be ready to execute its survival plan and that these plans mainly involve shelter-taking. 

  During the planning phase, the entire city organization will be involved through the EOC. One of the key results is that of citywide survival plans for the problem facilities mentioned in the previous chapter: schools, hospitals, nursing homes, penal institutions and the like. Representatives of the institutions or facilities are most likely to come up with workable survival plans that can be incorporated into CD district plans.

  Imagine that within the big-city EOC is a big map of the urbanized area. At the location of each fire house is a little white light that is kept lit by an always-on transmission from the fire house similar to identifier transmissions from aircraft.  If a huge explosion should take place somewhere in the urbanized area, one or more (a cluster) of lights will go out, defining the location of the explosion. The response on the ground is automatic. The rescue columns from surviving fire stations roll toward the explosion site based on eyeballing the cloud and reports of BOS 4 or higher. Everywhere in the city the population will be moving into the sheltering mode.

  Only a few minutes after the explosion the rescue columns from the fire houses nearest it will report BOS 2, confirming a nuclear explosion and giving the first clue as to the downwind direction of the fallout. By waiting this long, however, several square miles of populated area have been exposed to fallout. Moreover, it will be very difficult to gain the attention of the population with instructions meant for only those in the downwind direction. It seems better to adopt an automatic response policy to be followed in every CD district whether threatened by fallout or not. Such policy effectively saves the most lives in the lethal fallout area. It should be acceptable in the much larger region outside the fallout area. (Perhaps 90 percent of fire houses will not see fallout.)

  From the big-picture viewpoint of the EOC, these instructions put everybody having the best shelter in the sheltering mode in all surviving CD districts. Most are not going to need it but it probably is best to leave them in the sheltering mode for several hours while the EOC is concentrating on the districts in the developing fallout area. As for those in vehicles, they are heading away from the explosion, which is the only way “out” at this early stage. They should be given encouragement and guidance to avoid a 60-degree sector around the developing fallout area. Suitable staging areas, such as a NFL stadium or a university campus, well clear of the fallout area, should be given them as  destinations. All those fleeing in automobiles are those with poor sheltering options.

  As a corollary to the above, the EOC must guide the police forces in the downwind direction in sequestering the fallout area as it develops. This means securing a swath of up to 15 miles during the first hour. A number of fire houses will report BOS 2 or BOS 3. Those police units nearby can make vehicular probes to locate the edge of the fallout area where checkpoints or road blocks should be created to prevent inadvertent or unauthorized entry into the fallout area. Needless to say, every police unit must be equipped with dose-rate meters. Surface public transportation will necessarily cease across the fallout area until probes establish its width and radiological decay projects inconsequential doses.

  Ultimately, everyone must be extracted from the fallout area. Nearly everyone in the fallout area is in good or very good shelter if the proposed planning guidance has been followed. Therefore, when the move out of shelters can occur depends mainly on the prospective dose during the move. The nature of radioactive decay after fission explosions is such that for every seven-fold increase in time after the explosion the dose-rate decreases by a factor of ten.  Refer to Table 6. Note that the times at which total doses are summed are 1 hour, 7 hours, and 2 days. These are seven-fold increases in time. Dose-rates have decreased ten-fold each time. For example, at 1 mile, the worst case, the dose-rate at 1 hour is 1500 r/hr. At 7 hours, it is 150 r/hr. At two days, the dose-rate would be 15 r/hr. If one took an entire hour to get out of the fallout area, the movement dose would be less than 15 r, an inconsequential exposure. That is why shelter stays longer than two days are not necessary.

  On the other hand. the deposit (r/hr at 1 hr) at 11 miles is 50 r/hr. At 7 hours, the dose-rate would be 5 r/hr and movement doses again inconsequential. Indeed, at 6 miles where the estimated dose-rate at one hour is 150 r/hr, the seven-hour dose-rate would be 15 r/hr. One would receive 3 r or less for each twelve minutes of movement time. With the outside only two miles or so away, insignificant movement doses would be projected. Thus, evacuation of shelterees out of the fallout area might begin virtually everywhere about six or seven hours after the terrorist nuclear explosion.

   Some portion of the shelterees in a building will have arrived there by automobile. The remainder will have arrived by foot, cab or public transportation. The preferred movement method is to send all automobiles out of the fallout area with empty seats filled by shelterees who did not come by auto. If there are any autoless shelterees left after all filled autos have departed, buses can be sent in for them. One can see why it is desirable to have security staff or volunteers trained for leadership in all buildings that might be used as shelters. 

  All autos exiting the fallout area should be directed to the nearest fire house where the vehicles should be hosed down (decontaminated) whether they sat in a parking lot or in a parking garage during the fallout event. The auto drivers then should be directed to a nearby high school or middle school for processing. 

  The public school system is an important distributed infrastructure in every city. The location of school buildings is primarily oriented toward the location of housing units. The volunteer group in every CD district should be aware of all schools within the district not only for the protection of students if the explosion occurs during the school day but also for the potential use of school buildings and staff to care for the population displaced by the fallout area. Note that not all who exit the fallout area are displaced. Those whose housing unit is within the fallout area are the truly displaced. This can amount to hundreds of thousands of persons under some circumstances. The Homeland Security Department has published guidance on the processing of displaced persons, including registry and locator procedures and data bases as well as medical screening and treatment procedures that need not be repeated here. As for timing, most of the housing units in the fallout area should become safely habitable within several weeks although some areas close to the site of the explosion may be restricted for several months. A good driving rain will be very helpful and, of course, the fire service is very good at pouring water on roofs and paved areas.

  Largely missing from this big picture is any detail on the fighting of fires and treatment of the injured by rescue columns in BOS 4 and BOS 5 areas as well as the probing and securing of the fallout area by mostly police units working in BOS 2 and BOS 3 areas. These BOS numbers, while useful as a brevity code, actually define basic operating situations for which training courses can be designed that will improve the ability of first responders to work effectively and swiftly in fallout areas without becoming victims themselves, Such training must await the availability of high-range dose-rate survey meters. The micro-rem instruments in use today give an inflated feeling of threat to inconsequential exposures. All described here is what is needed to survive and recover from a terrorist nuclear explosion.