98 EFFECTS OF IONIZING RADIATION With regard to the problem ofdoserate, there is essentially no difference in effect of a given dose delivered over a few seconds, a few minutes ora few hours. However, a dose delivered over several days or weeks will be muchlesseffective for some effects, than will the same dose delivered over a few minutes. Somedata indicate that the effect of a given total dose decreases roughly as the fourth root of the numberof days over which the dose is given; thus, a dose delivered over 16 days would be one-half as effective as the same dose delivered over one day. These relationships were worked out on animals, using the so-called “rectangular” dose schedules, e. g., doses delivered at a constant rate. There are no data available to aid in evaluating adequately the effect of a constantly changing dose rate as encountered in a fission product field. Also, the relationships were worked out using acute effects, such as 30-day mortality and it is not at all certain howclosely they apply to longer-range effects such as cancer production, shortening of life span, etc. Genetic effects apparently are dependent on total dose and showlittle or no dependence on dose rate. 6.34 The Effects of Beta Radiation From Fallout Extensive beta lesions from fallout in human beings had not been encountered previously. As described in Chapter ITI, the lesions, both clinically and histologically, were consistent with previous data on experimental human and animal beta ray burns. Several points should be made regarding the beta lesions from fallout radiations. Beta le- sions of the skin and depilation can occur in the absence of lethal doses of gammarays and can be serious. Thus steps should be taken to prevent them. And it would appearthat, with reasonable precautions they can be prevented,or at least markedly reduced in severity. Contact, of the fallout with the skin can be prevented by remaining within suitable shelter or by wearing ordinaryclothing. If exposure cannot be prevented, early and complete decontamination of the skin and hair would prevent or lessen the severity of the lesions. Particular attention should be given to the hair because of the like- lihood of activity being trapped there. If the hair is contaminated, and it cannot be cleansed promptly by washing, clipping or shaving should not be delayed. 6.35 The Effects of Internal Emitters From Fallout The fallout material can be inhaled or ingested and it will, of course, contaminate exposed food or water supplies. Thus, as with beta burns the possibility of a hazard from this source is possible. As with the beta burns, however, the problem may not be too serious and relatively simple measures will aid in minimizing exposure. The particle sizes of the fallout material probably will exceed the opti- malsize for a major inhalation hazard. From data on the Marshallese exposedto fallout, it is seen that the degree of internal hazard in the exposed persons was small. This is encouraging, since these peoplelived in a relatively primitive state where maximum probability of contamination of food and water supplies existed. If the hazard was minimum underthose conditions, it should be even less under conditions of modern American living. With all of the testing of nuclear devices in Nevada and elsewhere, the level of strontium, the most important fission product as far as internal hazard is concerned, is still only about 1/1000 of the permissible body burdenas recommended by the National Committee on Radiation Protectionin National Bureau of Standards Handbook 52, for industrial workers (9). The problem should not be neglected, however. Theeffects of internally deposited radioactive materials may not become apparent for many years and, thus, the problem in the Marshallese will not be fully evaluated for years. Every possible precaution against inhaling radioactive material, or of ingesting contaminated food and water should be taken. Gas masks that efficiently remove fission product particles from the air are available and even a wet cloth over the face is of considerable value for this purpose. Sprinkling of an area is effective in reducing the amount of dust in the air. Plain water, or soap and water will remove a large