Rain radiation dissipates relatively quickly over time. Most areas become safe to travel and decontaminate after three to five weeks. If you were outside when the rain hit, it is important to remove any contaminated clothing and clean or wash any exposed skin. Hand sanitizer does not provide protection against fallout.
Avoid touching your eyes, nose, and mouth if possible. Do not use disinfectant wipes on your skin. To wash away any fallout from uncovered skin or hair, take a shower or wash with soap and water. If you cannot shower or wash, use a clean, damp cloth to clean the affected areas. The Centers for Disease Control and Prevention (CDC) website provides information on the radioactive consequences of nuclear weapons tests conducted in the atmosphere around the world (global weapons tests) during the 1940s and 1950s.
A nuclear electromagnetic pulse (PEM) is the time-varying electromagnetic radiation that results from a nuclear explosion. The Comprehensive Nuclear-Test-Ban Treaty (CTBT) is a legally binding global ban on the testing of nuclear explosives. When a nuclear detonation occurs, people, plants, and animals can be exposed to fallout in a variety of ways. Even though there is still very little fallout in the environment, it is important to remember that it can be very dangerous. Based on estimates, the consequences of the more than 500 megatons of nuclear tests until 1970 will produce between 2 and 25 cases of genetic diseases per million live births in the next generation.
This web page provides information on the radioactive consequences of nuclear weapons tests in the atmosphere conducted during the 1940s and 1950s. The 1963 Test Ban Treaty prohibits the testing of nuclear weapons “or any other nuclear explosion in the atmosphere, in outer space and under water”. An example is the 1962 report of the Federal Radiation Council, entitled “Health Implications of Fallout from Nuclear Weapons Testing through 1961”. It also provides a brochure from the 1950s on the consequences and several images related to nuclear weapons testing and fallout shelters. The highest levels of outdoor fallout radiation occur immediately after its arrival and then decrease over time.
Since large doses of radiation of approximately 20 roentgen or more (see radioactivity note) are needed to produce developmental defects, these effects would likely be limited to areas of heavy local fallout in nuclear warring nations and would not become a global problem. The 1963 Limited Nuclear-Test-Ban Treaty ended atmospheric testing for the United States, Great Britain, and the Soviet Union, but two major non-signatories, France and China, continued nuclear testing at a rate of approximately 5 megatons per year.
