A collection of just-in-case info.

My understanding is: in the unlikely event of a nuclear event, there will be fallout that may spread wide distances (e.g., from Ukraine to USA). In the fallout could be radioactive iodine. Your thyroid collects and stores iodine. You don't want your thyroid to collect and store the radioactive iodine, so by taking these tablets in such an emergency, your thyroid won't need to store the radioactive iodine and doing this will help prevent thyroid cancer.

You should only take KI tablets when told to by government officials as there are dangerous side effects. I'm keeping some on hand in case of an emergency, and when CDC or FDA recommends taking KI, and if there isn't enough available from other sources, so that I can take it within the 3-4 hours recommended after exposure.

• https://www.nrc.gov/about-nrc/emerg-preparedness/about-emerg-preparedness/potassium-iodide-use.html
  “In the event of a radiological emergency, if taken properly, KI may reduce how much radioactive iodine the thyroid gland is able to absorb, potentially reducing an increase in the risk of developing thyroid cancer.”
• https://www.cdc.gov/nceh/radiation/emergencies/ki.htm  – lots of good info here
  “KI (potassium iodide) blocks radioactive iodine from entering the thyroid. When a person takes KI, the stable iodine in the medicine gets absorbed by the thyroid. Because KI contains so much stable iodine, the thyroid gland becomes “full” and cannot absorb any more iodine—either stable or radioactive—for the next 24 hours.”
• https://www.fda.gov/drugs/bioterrorism-and-drug-preparedness/frequently-asked-questions-potassium-iodide-ki  – has link to info for doctors and dosage info
  “KI works best if used within 3-4 hours of exposure.”
  “When administered in the recommended dose, KI is effective in reducing the risk of thyroid cancer in individuals or populations at risk for inhalation or ingestion of radioiodines. KI floods the thyroid with non-radioactive iodine and prevents the uptake of the radioactive molecules, which are subsequently excreted in the urine.”