The biggest health risk after an accident at a nuclear plant or a nuclear attack results from exposure to radioactive iodine. Other radioisotopes are dispersed and quickly excreted, but radioiodine is concentrated and retained in the thyroid, increasing your risk of thyroid cancer. Even tiny doses, which can be carried downwind for hundreds of miles, can be harmful. Children are at greatest risk. Taking potassium iodide (KI) before or immediately after exposure saturates your thyroid gland with safe stable iodine so that the uptake of radioactive iodine is blocked. There won’t be time to get it when an incident occurs. So if you live downwind of a nuclear plant, or worry about a nuclear attack, you might want to keep some KI tablets at home. (But please note that this may not protect you from the radiation of a terrorist “dirty bomb” made of spent nuclear waste) The FDA recommends keeping a 14-day supply on hand; radioactive iodine has a half-life of eight days. Only two brands have received FDA Approval, Iosat and Thyroblock. Children should take half an adult dose. A related salt, Potasium Iodate, (KIO3) is less bitter, and may stay down better in babies.