It's that most people in the US are deficient in Iodine because of Bromine its in sooo much of our food it blocks our ability to absorb iodine. It's why most americans have messed up thyroids and why thyroid cancer is increasing rapidly. The type of iodine you take is what really matters. Not as an emergency but on a daily basis as part of a routine. From what I've read potassium iodine is the best one to take. Our diet is horrible here & for a country where most people are overweight it's ironic that the root cause is we all have vitamin deficiencies.