Most casualties caused by nuclear accidents or explosions are caused by thyroid radioactive iodine poisoning. Children are the most dangerous.
Potassium iodide is a thyroid blocker used to handle radiation emergencies. Taking potassium iodide before exposure can reduce the risk by 95%.
A large number of reports indicate that the use of stable iodine before or immediately after ingestion of radioactive iodine can prevent radioactive iodine from entering the thyroid, or reduce the accumulation of radioactive iodine in the thyroid. The timely use of potassium iodide can help prevent diseases such as thyroid cancer. Otherwise, exposure to radioactive iodine leaked from a nuclear accident and spreading through the air may cause this disease.
At the same time, it has been reported that by using iodide, almost all radioactive iodine (> 90%) that may be taken up by the thyroid can be blocked. In 1978, the US Food and Drug Administration (FDA) discovered that the use of potassium iodide in a radiological emergency was "safe and effective" and approved its sale as an over-the-counter drug.