Ionizing radiation from nuclear plants and explosions can damage human health by breaking chemical bonds and causing cancer. The effects depend on exposure time, with initial symptoms being nausea and fatigue and higher exposures potentially causing organ damage, loss of consciousness, and death. Two types of radiation produced by nuclear reactions - cesium-137 and iodine-131 - are especially dangerous as they can accumulate in food and water and irradiate the body from inside over long periods of time due to their long half-lives. Exposure levels over 500,000 microsieverts can make people sick within hours or weeks depending on dose.

1. Possible health effects of nuclear crisis July 18 - July 24 Article #1