(Originally published July 25, 2015 on https://athf3.wordpress.com/)
If you’re caught in the plume of fallout from a “nuclear event” (reactor meltdown or nuclear bomb), taking a potassium iodide pill is one of the few things you can do to protect yourself from fallout. It’s only partial protection, and you should still do everything possible to to get away from the fallout, but it will go a long way toward preventing thyroid cancer.
Radioactive iodine (Iodine-131 is the specific radioactive isotope.) is one of the major products of a high-energy nuclear event. It forms about 3 percent (by weight) of the breakdown products of uranium and plutonium. When you breathe the fallout, iodine-131 is readily absorbed into your bloodsteram. Your thyroid gland then pulls iodine out of your bloodstream and holds onto it. Thus the thyroid gland will get a concentrated dose of beta and gamma radiation.
If the thyroid and the bloodstream were to be saturated with the non-radioactive isotope, iodine-127, then not so much of the radioactive isotope will be absorbed in the first place. What is absorbed is much less likely to be held by the thyroid gland. Along with the excess non-radioactive iodine, the radioactive variety will be excreted fairly quickly. Potassium iodide is the same chemical added to table salt to make it “iodized.” The protective pill has a larger quantity for a daily dose.
Taking a potassium iodide pill will not protect you at all from uranium, plutonium, strontium, cesium or any other radioactive elements in the fallout. With or without potassium iodide pills, you still need to get away from the fallout. But if you are in the plume, it is better to have the pills on hand than not to have them.
Because there is a very real possibility of a reactor core meltdown, the Nuclear Regulatory commission requires free potassium iodide tablets to be “available” to people living within ten miles of a commercial nuclear reactor. This applies to people living that close to DTE Energy’s Fermi 2 installation.
The way pills are “available” is that they are “stockpiled” at local pharmacies. Residents can go to a local pharmacy and get a pill (good for 24 hours of coverage) for every member of the household. About 95% of eligible residents have not done so. Accordingly, about 95% of residents, in case of that meltdown, are even more screwed than the 5% who have the pills on hand. After the meltdown, it will with few exceptions be far too late to run down to the local pharmacy in the chaos and panic of an emergency evacuation.