The build-up of radioactive iodine in the thyroid gland can be reduced by taking an iodine tablet. The efficiency of this measure depends on correct timing. The tablets must therefore only be taken when instructed by the authorities.

A serious nuclear power station accident may release radioactive iodine into the atmosphere. Iodine typically builds up in the thyroid gland when it enters the body by inhalation, for example. The radiation dose absorbed by the thyroid gland may lead to thyroid cancer or hypothyroidism.

If the air is expected to contain a large amount of radioactive iodine, people are advised to take iodine tablets. Taking an iodine tablet as advised prevents the absorption of radioactive iodine by the thyroid gland. The non-radioactive potassium iodine contained in the tablet fills up the thyroid gland in such a way that it prevents the absorption of radioactive iodine into the gland.

It is especially important that children and pregnant women take iodine tablets, because the thyroid glands of children and the foetus are more sensitive to radiation than those of adults. If there are not enough tablets, the tablets are given to children and pregnant women.

Correct timing is important. The protective effect of the tablet is reduced if the tablet is taken too early or too late. Iodine tablets do not protect you against other radioactive substances.

The iodine tablet only protects the thyroid gland; it does not reduce any other types of exposure. Do not go outside to become exposed when you have already been advised to stay indoors. Taking cover indoors significantly reduces the amount of radioactive substances entering the body by inhalation, thereby also reducing the dose absorbed by the thyroid gland. Taking iodine tablets is a complementary precaution to staying indoors.

How to use the iodine tablet

• Only take the iodine tablet when advised by the authorities to make sure that the timing is right. Instructions will be given on the radio and television. Follow the dosage instructions on the package.
• It is especially important that children and pregnant women take iodine tablets.
• Only take one dose. It provides protection for approximately 24 hours. The exposure by inhalation caused by the radioactive plume is likely to only last a couple of hours. If the release recurs or lasts longer, the authorities will advise you on the radio and television to take another dose.

Do not take the iodine tablet

• if you have previously had a serious allergic reaction to iodine
• if you have or have previously had a thyroid condition
• if your thyroid gland has been removed or does not work.

How to obtain iodine tablets

You can buy iodine tablets at the pharmacy.

The Finnish authorities advise

• citizens to procure iodine tablets for their homes and holiday homes
• housing cooperatives to keep a reserve of iodine tablets for the residents
• workplaces, schools, health-care centres, day-care centres and other care facilities to obtain iodine tablets for each employee and customer.

Power companies are responsible for the procurement and distribution of iodine tablets within a five-kilometre radius of the nuclear power plant.