Answer to Question #4999 Submitted to "Ask the Experts"

This is a good question which provides me with the opportunity to address two important and often misunderstood concepts which you can convey to your students: (1) the difference between exposure to radiation and contamination and (2) limitations of stable iodine (in the form of potassium iodide or KI) as a countermeasure.

For communicating the subtle but important distinction between exposure to radiation and contamination, you may find a fact sheet from the Centers for Disease Control and Prevention (CDC).

Regarding KI or stable iodine, as you know, it only protects the thyroid gland when there is an intake of radioactive iodine. There are no pharmaceutical alternatives for individuals who are sensitive to iodine. However, there are practical alternatives which are likely to be more effective than taking KI alone. If there is a likelihood for release of airborne contamination as a result of a nuclear power plant incident, the primary protective action measures recommended to the public are evacuation or in-place sheltering (as advised by public health authorities). Use of potassium iodide is considered only a supplemental measure. See the Federal Emergency Management Agency Policy on Use of Potassium Iodide (KI).

The Food and Drug Administration (FDA) clearly states that persons with known sensitivity to iodine should avoid KI. These individuals, as well as neonates and pregnant and lactating women (in whom repeat administration of KI raises particular safety issues), should be given priority with regard to the other protective measures (i.e., sheltering, evacuation, and control of the food supply).

To read more about potassium iodide use and its limitations, you can visit these two HPS pages:

Is Potassium Iodide a "Magic Bullet" for Radiation Exposure?

HPS fact sheet on KI

Armin Ansari, PhD, CHP