Potassium Iodide

Potassium Iodide (KI) is a protective, over-the counter supplement which helps to protect the thyroid gland against internal uptake of radioiodines that may be released in the unlikely event of a nuclear reactor accident.  Detailed information about KI is available by clicking Potassium Iodide (KI) Fact Sheet 11Jan13.

Not all nuclear power plant accident scenarios may result in a release of radioiodine requiring the distribution and use of KI. Nuclear power plants are designed to remove certain radioactive materials during an accident using filters and sprays. However, in ceratin types of accidents this may not always be possible.

The Nuclear Regulatory Commission (NRC) provided KI to states for use in the 10 mile plume phase emergency planning zone (EPZ) of commercial nuclear power stations.

VDH will recommend distribution and use of KI for members of the public at the Emergency Evacuation Centers (EAC) when the projected radiation dose to the thyroid gland exceeds 5 rem.

KI that will be made available to emergency workers and the public is shown below, followed by lot numbers and expiration dates:


ThyroSafe 65mg Tablets

The shelf life of ThyroSafe 65mg KI tablets, Lot #s TU404A and TU405A, (with a printed expiration date of 4/2020) has been extended to April 30, 2022.

Please refer to the letter available at this link for additional details: Virginia Potassium Iodide (KI) Extension Letter 03182020 

Other Information about KI

U.S. Nuclear Regulatory Commission’s web page on KI:


U.S. Food and Drug Administration’s (FDA) web site on radiation emergencies:


FDA Guidance: Potassium Iodide as a Thyroid Blocking Agent in Radiation Emergencies:


Centers for Disease Control and Prevention:



Office of Radiological Health | 109 Governor Street,  7th Floor | Richmond, VA  23219

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