ATOMIC ABCs

Behind the low-rolling smoke of battle in Korea looms the most terrifying of all war clouds: the topless mushroom of the atomic bomb. Will the Russians make an atom-bomb attack on the U.S.? If it comes, what is the defense? Is there any defense? Last week the Atomic Energy Commission and the Department of Defense issued a 456-page volume, The Effects of Atomic Weapons* which gives the first official answers to some of these questions. In it are the ABCs of atomic disaster which every civil-defense planner--and every dweller in a target area--should know: what an atomic attack would mean, and what to do about it.

WHAT THE BOMB DOES

Although an atomic bomb/- is thousands of times more powerful than an ordinary bomb, there are limits to its power and destructiveness. Those limits depend not only on the size of the bomb, but also on how and where the bomb is exploded -- and how well the defense is organized to meet it.

What happens when the bomb goes off?

Atomic bombs might be exploded in the air over U.S. cities, under water, or at ground level. Though the effects are different in each case, the principle is the same. At the instant a bomb explodes overhead, fission turns it into a rapidly growing "ball of fire," which dims for an imperceptible instant, then grows to a diameter of 900 feet at a temperature of 7,000DEG C. (see diagram). Around the fire ball forms a shock wave -- a shell of air compressed so tightly that it glows white-hot.

The shock wave rushes out like a solid steel wall. At some points it is joined by a reflected wave. The two combine to apply redoubled pressure (called the "Mach front"). Behind the shock wave comes a great wind, at a speed of 800 m.p.h. A mile from "ground zero" (the point directly under the burst), the speed of the wind drops to 200 m.p.h.; 1 1/2 miles away, to 100 m.p.h. Behind the wind comes a partial vacuum, which acts like another wind coming from the opposite direction. Three miles away, the shock wave, wind and vacuum begin to peter out.

Much of the bomb's energy is released as radiation-- heat and light, which shoot out from the fire ball a fraction of a second after the explosion. Five miles away, the light glares as brightly as 100 suns; up to half a mile the heat waves sear everything directly in their path. Then, too, comes the flood of gamma rays (nuclear X rays). Trapped at first within the fire ball, these deadly rays burst forth a fraction of a second after the bomb explodes.

What will the bomb do?

A bomb exploded 2,000 feet above the ground would do the greatest damage. Virtually everything within a radius of half a mile by ground zero will be destroyed or irreparably damaged by the blast, the heat, or by fires started by the heat. Within the next mile, countless fires will be started by the heat radiation. As many fires will be started by broken gas lines, electrical short circuits. Broken water lines will make fire-fighting almost impossible.

Up to the half-mile radius, the gamma rays will be powerful enough, even after penetrating brick or concrete walls two feet thick, to kill or gravely injure people well protected from heat and blast. Beyond the half-mile radius, the rays' deadly power will decrease, gradually at first, then sharply; two miles from the explosion they will be virtually harmless.

A bomb exploded at ground level would expend much of its energy in digging a crater. Thus the destruction, although more devastating around the detonation point, would be limited to a smaller area than in the case of an air burst. A bomb exploded under water would also lose some of its blast effect, but would throw up an immense column of radioactive water, to contaminate everything on which it fell.

What will happen if a bomb hits a city?

That depends on the city: what kind of buildings it has, how thickly it is built up, whether it is built on a plain, in a valley, or on hills (which shield the areas behind them). With this AEC information as a guide, New York State's Civil Defense Commission, headed by General Lucius D. Clay, last week made an estimate for New York City:

Within three-quarters of a mile of the burst, "substantial destruction of all except modern, reinforced concrete and heavy steel-frame buildings; up to 1 1/2 miles, complete destruction of most old-style brick and frame buildings, and serious damage to modern buildings. Slight damage (plaster and glass) up to eight miles away. For at least two miles from the burst, streets blocked by rubble, and power, light and water lines knocked out.

A burst at ground level, or near it, might result if a bomb dropped from the air failed to detonate at the most effective height. Then everything covered by the bomb's ball of fire (900 feet across) would be fused or vaporized. Outward from the center would be circles of death and damage exactly like those of an air burst, but smaller. Radioactive dust, from pulverized buildings, would be an added menace for those in the path of the wind. The central crater (as at Alamogordo) would be a no man's land for months, perhaps indefinitely, because of lingering radioactivity in fused steel and stone.

A bomb smuggled in aboard ship might be set to explode under water at about the same time as one dropped from the air. Its shock wave traveling through the water would crush the hulls of ships in port. A million tons of radioactive water thrown into the air would smash nearby piers and warehouses, splash on others farther away, making them unapproachable for weeks or months. A wind-borne mist laden with deadly radioactive particles would threaten survivors to leeward.

How will U.S. buildings stand up?

Not much better than the Japanese ones. Because of quake-proof construction, many Japanese buildings in Hiroshima and Nagasaki were even stronger than most modern U.S. buildings. U.S. houses have a slight edge over Japan's "paper houses." Houses 7,500 feet away from the burst might survive (compared with a safety limit of 8,500 feet at Nagasaki).

What will the atomic bomb do to people?

The great majority (85% or more) of those in a half-mile radius from the burst will die. Most of these will be killed instantly by blast, heat or falling masonry. Others will get a fatal dose of radiation.

Up to three-quarters of a mile away, 50% of the people exposed may die from gamma radiation, some in a few minutes, some not until weeks later. Of those within a mile and a quarter, many will die or be horribly burned by heat radiation. Within a mile and a half, flying glass, falling masonry and fires will cause many more deaths.

How many casualties?

The probable toll would be much like that at Hiroshima (70,000 killed, 70,000 injured). Within 3,000 feet of the burst, 80% died. At 4,500 feet the mortality rate was down to 50%, at 6,500 it was 15%. Some U.S. cities in business hours have 150,000 to 250,000 people in the four-fifths of a square mile covered by the half-mile radius. An air burst over them would kill many more than died at Hiroshima.

What will the aftereffects be?

After a high (2,000-ft.) air burst, lingering radioactivity will not be serious. Rescue workers will be able to enter the ground-zero area a few minutes after the blast, with only the simplest precautions.

The delayed effects of radiation received in the human body an instant after the blast are more serious, and may cause lingering death. However, no more than 15% (perhaps as few as 5%) of the casualties at Hiroshima are now known to have been caused by radiation sickness. Most survivors of radiation sickness recover completely. Stories of widespread, permanent sterility are now known to be groundless. Shortly after exposure, pregnant women are likely to miscarry, and children conceived in this period may be monsters. But after two or three months, the danger of such aftereffects wears off.

What are the likeliest U.S. targets?

Aside from military installations, they are the great cities with massed industry such as New York, Chicago, Philadelphia, Pittsburgh, Detroit, Los Angeles. Washington is another obvious target. Small cities (below 100,000 pop.) are unlikely targets unless they house a plant making critical war supplies (bomb-sights, roller bearings, "peanut" tubes for proximity fuses).

Prime industrial targets : oil stores and refineries, chemical plants, railways and docks, dams and power plants.

Can atomic bombs destroy the world?

As far as AEC knows, no. AEC has calculated that to make the world uninhabitable by making its surface radioactive would take 755,000 Hiroshima-type bombs -- and nobody has anywhere near that many, or is likely to.

WHAT TO DO

Real atomic defense is a long-range job on a national scale. It would take years and cost billions to disperse industries, put key plants underground, build huge, deep shelters for city dwellers. But local civil defense units can do plenty now. Civil defense headquarters and many of the police and fire-fighting forces should be scattered around the edges of a likely target area, not huddled in the middle. Emergency first-aid squads should be spotted everywhere. They will need an ocean of blood, plasma and plasma substitutes for transfusions. They will need a mountain of bandages to dress burns and other injuries. Buildings such as schools should be set aside as emergency hospitals. There must be plans for evacuating, sheltering and feeding the myriad homeless.

Effective shelters can be built inside most buildings, or below ground level, with foot-thick reinforced concrete. Outside shelters should be at least partly buried, and well away from buildings which might catch fire. Doors are not needed on shelters, but two entrances are necessary, each with a turn or baffle to stop the bomb's direct heat rays and much of its radiation. For a few cities, subways offer ready-made shelters.

What should I do when the bomb bursts?

If the air-raid warning system gives you time, get off the street and into a shelter. If no shelter is near, get away from windows and inflammable material (especially your car with its tank of incendiary gasoline), and drop to the ground. If you are in a tall building, go to the middle of the floor or, better still, to the ground floor or basement. If you are at home, go to the basement.

Suppose there is no warning?

For those directly under an air burst there may be no warning; there is nothing they can do, anyhow. But if the bomb bursts a mile or more away, it gives its own warning: the 100-sun glare of the fire ball. Then, says AEC, don't look--duck. If you are in the open, drop to the ground and curl up so as to cover your arms and hands, face and neck as much as possible. Even paper or cloth will cut down flash burns; stepping into a shadow may reduce heat radiation below the danger point.

If you are in the street, and there is a doorway, corner or tree within a step or two, take shelter there. Turn your back to the light and hug the building, to avoid falling masonry or flying glass.

At home, anyone seeing the warning flash should drop to the floor, with his back to the window, or crawl behind or under a table or desk.

What about the "death rays"?

Most of the radioactive contamination from an air burst will be in the central area; few can escape. But heavy rain, strong wind, or an underwater burst may spread radioactive matter to areas with many survivors. They should get out of their clothes as soon as possible and wash themselves with soap, or better, the "soapless" detergents now in most U.S. kitchens.* Lacking water or soap, vigorous rubbing of the skin with uncontaminated paper or cloth will help.

Will it be safe to eat the food in a bombed area?

Only if it is in tight containers--preferably cans.

How long does the danger last?

Gamma radiation travels with the speed of light and is gone instantly. Heat radiation lasts as long as three seconds (which may be time enough to duck into a doorway or sprint a couple of steps around a corner). The blast or shock wave races a mile in five seconds. After an air burst, stay where you are for at least a minute, and watch out for falling debris. After an underwater burst, the danger from radioactive mist may last for several hours.

Preparations and precautions such as these, says AEC, may mean the difference between life & death for tens of thousands.

*From the Superintendent of Documents, $1.25; in trade editions (Rhinehart, distributing for Combat Forces Press, and McGraw Hill), $3.

/-Of the fission type used to date, as distinct from the fusion or hydrogen bomb, which has not yet been made.

*A New York City concern called Atomlab this week demonstrated "Radiacwash," a solution for washing radioactivity away. Where water and a strong detergent had failed to decontaminate a beaker in several scrubbings, it was claimed that "Radiacwash" got rid of 95% of the radioactivity in a half-minute scrub.

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