Potassium Iodide (KI) Use in San Luis Obispo County

Should a nuclear power plant emergency occur that involves a release of radiation, government officials may direct evacuation or shelter in place as a protective action. The ingestion of KI tablets may also be directed as a supplemental protective measure.

KI is not an “anti-radiation” pill. It is only a supplemental protective measure, secondary to evacuation or sheltering in place. KI protects the thyroid gland against exposure to radioactive iodine in the unlikely event of a radiological release from a nuclear power plant. If ingested in an appropriate and timely dosage, KI may block the uptake of radioactive iodine by the thyroid gland. However, KI does not protect other parts of the body from exposure to radioactive material that may be released during an emergency. 

A free two day supply of potassium iodide (KI) is available for residents who live or work within a Protective Action Zone (PAZ). Participation in the pre-distribution program is voluntary. A KI voucher is available in the annual Emergency Planning Calendar. KI can also be ordered from several commercial manufacturers by telephone, mail, or via the internet.

KI will not be available at Monitoring, Decontamination and Reception Centers. You must pick it up in advance of an emergency at one of the pre-distribution locations.

KI should only be ingested after specific instruction by a state or local public health official.

How Much Potassium Iodide (KI) to Ingest

One Tablet = 65 milligrams of KI

Adults 18 years or older

Two Tablets

Pregnant or nursing women

Two Tablets

Adolescents 12 – 18 years old

1 – 2 Tablets*

Children 3 – 12 years old

One Tablet

Children 1 month – 3 years old

Half Tablet

Infants, birth to 1 month

Quarter Tablet

* Adolescents approaching adult size (equal to or greater than 150 pounds) should receive the full adult dose.


If You Need KI for Your Home or Workplace:

County of San Luis Obispo Public Health Department Locations:

  • Grover Beach: 286 South 16th Street
  • San Luis Obispo: 2191 Johnson Avenue

More information regarding pre-distribution and a downloadable voucher can be found at the San Luis Obispo Public Health Department website.


Potassium Iodide Expiration

It is important to check your KI supply from time to time and ensure it is within its expiration date.  If your KI is expired, please pick up a new box at one of the locations above.