janjbs,

All the responses have been on the money. However, if you don't live within a specific radius of a nuke plant, the government doesn't issue you any. I keep one in my wallet and my wife her purse. Extra in the glove compartment and BOB. The Potassium Iodide tablets used by the government is called "IOSAT" and are available from nukepills.com. They are nice because each pill is in an individual foil wrapper so they can be seperated (as opposed to those that come in a bottle). Very reasonably priced. Hope this helps.

Fox10