Atomic Bombing: How to Protect Yourself


Nearly a quarter of an inch of wood must be shaved away to remove contamination.
8. DECONTAMINATION

At Bikini they tried first to wash away the radioactivity. Fire hoses flushed the battered wrecks of ships with sea water. Steel superstructures frothed with soapsuds. Squads of sailors -- led by monitors of the radiological safety section -- sweated hours and then days holystoning the wooden decks of battleships and cruisers. Back and forth with sandstone bricks, rubbing until the decks gleamed white in the sun. The sailors could see no poison on those decks. But each time they finished rubbing, the Geiger man would shake his head, and the work would start again.

Then a scientist took a small block of the wood into the laboratory. He found that nearly a quarter of an inch had to be shaved away with a plane -- the entire top surface of the deck skinned off -- before the Geiger counters would be quiet.

Weeks after the "Baker" test, the underwater blast, a sailor was working on a rusting, twisted landing craft on the atoll beach. One hand slipped while he was hauling at a steel cable, and a small cut appeared between thumb and forefinger. Taken to sick bay on the radiological ship, the white-faced seaman waited while delicate tests were made on the open tissues of the wound. If contamination by the invisible poison of atomic fission were found, his arm would have to come off at the shoulder. High amputation was a hard-and-fast rule in the Manhattan District project for such cases. This cut was little more than a scratch -- but the cable had been checked and found to be still radioactive.


The ships of the target fleet swung at anchor, silent and deserted.
The cut was free of contamination, luckily. The sailor went his way with merely a small bandage on his hand. But the incident went down in the terrifying record written by Atomic Bomb No. 5 -- the first to be exploded under water, not high in the air, and the first to leave man faced squarely with the silent specter of radiological poisoning. In the underwater burst, radioactivity touched the target ships and remained. It patrolled the decks with an invisible barrier which men could cross, but only for a given length of time; then the men had to leave. The ships of the target fleet swung at anchor, silent and deserted. No one knew quite what to do with them.

Radiation dosage is measured in terms of the roentgen or "r" named for Wilhelm Roentgen, the German physicist who discovered X-rays in 1895. It is usually accepted that a dose of 400 r of radiation received over the entire body in a few minutes is a "median lethal dose" -- that is, it would be fatal to about 50 percent of human beings who received it. In radioactivity left behind after an atomic bomb explosion, however, or deposited in radiological attack, the problem of radiation is quite different from a "one-shot" dose. While a human being would have only a 50-50 chance of survival if he received 400 r of radiation all at once, the same amount of radiation spread over a period of a month would be far less dangerous.

Residual radiation from an atomic blast must be measured not only in terms of how strong it is at any one time-the dosage rate -- but also the total amount of radiation received over a given length of time. In 1936 the U.S. Committee on X-rays and Radium Protection set the figure of 0.1 r per day as the maximum dose a human could receive over the whole body, day after day, without suffering permanent harm. To give an even greater margin of safety, the Atomic Energy Commission later lowered this maximum allowable dose to 0.3 r per week for workers in U.S. atomic plants and laboratories. This was the figure used in handling the ships at Bikini after the Crossroads tests.


The Independence was towed back to San Francisco.
The U.S.S. Independence, a small aircraft carrier, received such a large dose of radiation from the "Baker" blast that it would have killed any crew members who might have been on the hangar deck. Two weeks after the blast the radioactivity of the ship had dropped to about 3 r per day. That meant decontamination squads could go aboard for short periods of time -- perhaps 20 minutes a day for any one man. A long year later, the Independence having meantime been towed back to San Francisco, the average dosage rate was down to 0.3 r per day -- still seven times the limit for full-time occupancy.

No decontamination was attempted on the Independence. The carrier was too battered ever to be used as a fighting ship again. But on other ships new knowledge of decontamination began to be accumulated, through the long, arduous process of trial and error. Some of the ships were decontaminated and put back into use, while the Independence lay at her moorings in San Francisco, still "hot" with radiation.

METHODS OF DECONTAMINATION

There are three courses open when an object is radioactive, whether it be a ship, a building or a heap of waste from a nuclear reactor: 1. bury it deep in the ground or jettison it at sea; 2. isolate it until the radiation level drops below the danger limit; or 3. decontaminate it.


Three courses are open when an object is radioactive.
Decontamination means, to a large degree, stripping away the radioactive surface, cleaning it either by chemical means or physical means. There are exceptions to this, of course: When a radioactive solution has soaked into a porous surface such as rope, cloth, unpainted wood, brick or stucco; when neutrons have set up radioactivity deep within the object; or when a reservoir of drinking water is contaminated.

If chemicals are to be used to clean a "hot" surface, the nature of the radioactive materials must be known. When uranium 235 fissions, as in an atomic bomb, nearly 200 radioactive products, isotopes of some 34 different elements, may be present. The chemistry of identifying these poisons is an intricate business. It is further complicated by the fact that a chemical reaction will not eliminate the radiation. It will merely turn the contaminating agent into a new form which can be flushed away. Something has to be done with the drainwater, after that.

But much was learned at Bikini about chemical decontamination. Compounds based on certain organic acids, such as ordinary citric acid, were found to be important agents for general decontamination. Detergents, the new synthetic soaps, were very useful. Even stronger alkalis were used in removing entire contaminated layers of paint. Acid solutions helped dissolve rust and scale.

Blasting with wet sand or high-pressure steam containing a detergent was used to good effect at Bikini and later. The wide range of physical decontamination methods included vacuum cleaning and light brushing to remove lightly held material, and use of a blowtorch to burn away entire coatings of paint. Adhesive coatings of various types were tried. These could be stripped away carrying radioactive materials with them. Special plastic paints which could be easily removed in case of contamination have even been considered by scientists as a means of minimizing the residual radioactivity after an atomic poisoning.

REDUCING CONTAMINATION AT HOME


Acids, detergents, and alkalis will remove contamination.
There are a number of things you can and should do in your own home after an atomic bombing, to reduce danger of radioactive contamination.

Your clothing will normally prevent radioactive residue from the bomb from reaching your skin. If there is any chance that your clothing is "hot," take off the outer layer and bury it. Do this before going into a building, such as your own home, for there may be no contamination inside the house until you unwittingly carry it indoors.


If there is any chance that your clothing is "hot" take off the outer layer and bury it.
Radioactive substances which come in contact with the skin may be more dangerous than a detecting instrument held an inch away would show. You should carefully cleanse any exposed parts of your body. Vigorous scrubbing with soap and water will accomplish a remarkable amount of decontamination. Pay particular attention to the hair, nails, skin folds and areas surrounding body openings. Be careful not to rub so hard that you break the skin, however. If soap and water does not remove the radioactivity, as shown on an instrument, a dilute solution of sodium bicarbonate may be used. This is particularly useful for rinsing mucous membranes, such as the mouth and nasal passages.

In a dire emergency, any clean uncontaminated material at hand, such as grass, paper, straw, leaves or sand, will remove radioactivity from the skin if rubbed on vigorously. These might be used, for example, if you were covered with water or soil thrown into the air by an atomic explosion. Again, do not tear the skin or force loosened material into wounds, body openings or skin folds.


Vigorous scrubbing with soap and water will accomplish a remarkable amount of decontamination.

For cleaning household objects, almost any method would be helpful. Cleaning and scouring compounds, grease removers, detergents, paint cleaners, dry cleaning liquids, gasoline, etc., will help to remove radioactive particles from surfaces. Be careful not to spread or rub in the radioactive materials, however. The cloths you use should be buried rather than burned, for radioactivity would be carried off in smoke.

DECONTAMINATION OF LARGE AREAS

While you are doing these things, the decontamination of vital areas of your city would begin. Crews would flush the streets with water, perhaps with the aid of detergents. Brushing or vacuum sweeping of outdoor areas might even be tried first, if feasible. Remember that there is no known way to neutralize radioactivity. Decontamination only transfers it from one place to another. Proper disposal of the "hot" material must be provided, carrying or flushing it to a place where it will not constitute a hazard.


Scrubbing the sidewalks and flushing the streets would be helpful.
One of the first steps in complete decontamination would be removal of the industrial film of grease and dirt which usually covers exposed surfaces, especially in cities. Radioactivity seems to attach itself strongly to such a film. Ordinary soap and water, detergents or live steam are among possible ways the film may be removed. In this initial work, decontamination crews would seem like men from Mars. They would have to wear protective clothing, such as rubber suits, boots and gloves. If spray or dust is involved, goggles and respiration masks must be worn. Sandblasting and strong chemicals would be used to remove the entire top surface from the outsides of important buildings. Other structures, where decontamination might be too costly, or the radioactivity too high, would have to be dismantled, carried away and buried.

In soil, the radioactivity would be held in the uppermost few inches. The top surface of parks and lawns in a contaminated city would thus have to be either removed or covered with at least a foot of fresh earth. This could perhaps be done by turning the soil over, so that lower uncontaminated layers covered the part that was "hot." Deep plowing of exposed lawns and vacant lots would begin, after the areas had been thoroughly wetted down to prevent radioactive dust from escaping into the air.


Deep plowing of exposed lawns and vacant lots would begin.
Badly contaminated clothing, rugs, curtains and upholstered furniture would have to be buried or burned in incinerators especially designed to prevent the escape of radioactive smoke. Lightly contaminated articles can be dry cleaned.

CONTAMINATION OF FOOD AND WATER

Gamma rays have no harmful effects upon food. Properly covered food should undergo little or no contamination, unless it has been within very close range of an atomic burst, where neutrons would make everything radioactive. Unless this is the case, canned goods and foodstuffs in airtight, dust-proof wrappings should be safe. But unprotected food, whether it be in the home, the store or still growing in fields, will have to be destroyed if once contaminated. There is no known way to salvage it.


City filtration plants would remove radioactivity.
Water supplies are not easily contaminated. Natural dilution, absorption into the ground, and decay of the radioactivity would quickly make the water fit for use again. City filtration plants would remove radioactive materials in the course of normal purification of the water. In addition, water from moderately deep wells, even under contaminated soil, would be safe to drink unless there is surface drainage into the well.

Water may be distilled and made perfectly safe. But it should be emphasized that boiling of contaminated water would do no good at all. Boiling is useless against radioactivity.

The most effective means of decontamination is to let the radioactivity die away by itself. This decay is rapid at first, slowing only when the more dangerous -- the really "hot" materials -- have spent their energy. In any future atomic bomb attack, the hazards of contamination will be secondary to the chaos wrought by blast and heat. And radioactivity, like measles or mumps, is a community danger which can be met and handled safely.