The administration ofPotassium Iodide (KI)is a specific protective measure used to protect the thyroid gland fromRadioactive Iodine (I-131), which is a significant byproduct of aNuclear Power Plant (NPP) releaseor a nuclear reactor accident. When a reactor core is compromised, I-131 can be released into the atmosphere. If inhaled or ingested (through contaminated milk or food), the thyroid gland rapidly absorbs it, significantly increasing the risk of thyroid cancer, especially in children.

KI works by saturating the thyroid with stable, non-radioactive iodine. Once the gland is "full," it cannot absorb any more iodine, including the radioactive variety, which is then safely excreted by the body. However, KIonlyprotects the thyroid andonlyagainst radioactive iodine. It provides no protection against other radionuclides likeCesium-137(Option B) or the wide array of isotopes found in a thermonuclear explosion (Option A). In a thermonuclear blast, while I-131 is present, the immediate threats from blast, heat, and other isotopes are so overwhelming that KI administration is secondary to "Shelter-in-Place" or evacuation.

According to theNRC (Nuclear Regulatory Commission)andCDCguidelines included in theCEDPmaterials, KI is distributed to residents living within the 10-mileEmergency Planning Zone (EPZ)of nuclear power plants. It is most effective when taken shortly before or immediately after exposure. Emergency managers must emphasize to the public that KI is not a "radiation pill" that protects the whole body; it is a thyroid-specific countermeasure. This distinction is vital for public health communication to prevent a false sense of security among residents who might think taking KI makes them immune to the effects of a "dirty bomb" or a medical facility leak where I-131 may not even be present.