The Effects of Nuclear War

GENERAL DESCRIPTION OF EFFECTS

Direct Nuclear Radiation

Nuclear weapons inflict ionizing radiation on people, animals, and plants in two different ways. Direct radiation occurs at the time of the explosion; it can be very intense, but its range is limited. Fallout radiation is received from particles that are made radioactive by the effects of the explosion, and subsequently distributed at varying distances from the site of the blast. Fallout is discussed in a subsequent section.

For large nuclear weapons, the range of intense direct radiation is less than the range of lethal blast and thermal radiation effects. However, in the case of smaller weapons, direct radiation may be the lethal effect with the greatest range. Direct radiation did substantial damage to the residents of Hiroshima and Nagasaki.

Human response to ionizing radiation is subject to great scientific uncertainty and intense controversy. It seems likely that even small doses of radiation do some harm, To understand the effects of nuclear weapons, one must distinguish between short- and long-term effects:

• Short-Term Effects.-A dose of 600 rem within a short period of time (6 to 7 days) has a 90-percent chance of creating a fatal illness, with death occurring within a few weeks. (A rem or “roentgen-equivalent-man” is a measure of biological damage: a “rad” is a measure of radiation energy absorbed; a roentgen is a measure of radiation energy; for our purposes it may be assumed that 100 roentgens produce 100 rads and 100 rem. ) The precise shape of the curve showing the death rate as a function of radiation dose is not known in the region between 300 and 600 rem, but a dose of 450 rem within a short time is estimated to create a fatal illness in half the people exposed to it; the other half would get very sick, but would recover. A dose of 300 rem might kill about 10 percent of those exposed. A dose of 200 to 450 rem will cause a severe illness from which most people would recover; however, this illness would render people highly susceptible to other diseases or infections. A dose of so to 200 rem will cause nausea and lower resistance to other diseases, but medical treatment is not required. A dose below so rem will not cause any short-term effects that the victim will notice, but will nevertheless do long-term damage.
• Long-Term Effects.-The effects of smaller doses of radiation are long term, and measured in a statistical way. A dose of 50 rem generally produces no short-term effects; however, if a large population were exposed to so rems, somewhere between 0.4 and 2.5 percent of them would be expected to contract fatal cancer (after some years) as a result. There would also be serious genetic effects for some fraction of those exposed. Lower doses produce lower effects. There is a scientific controversy about whether any dose of radiation, however small, is really safe. Chapter V discusses the extent of the long-term effects that a nuclear attack might produce. It should be clearly understood, however, that a large nuclear war would expose the survivors, however well sheltered, to levels of radiation far greater than the U.S. Government considers safe in peacetime.

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