Possible Radioactive Nuclear Contamination in Japan (Global news)

First and foremost we would like to express our sincere sympathy to all the people affected by the tragic earthquake on March 11, 2011 in northeastern Japan.

Camfil Farr has been working in the nuclear filtration application field for more than 50 years and over 100 out of the 432 nuclear power plants worldwide are equipped with our containment safety applications. We receive a lot of questions about the possible radioactive emissions from the Japanese nuclear power plants and would like to share our answers to the most commonly asked questions. Camfil Farr would like to point out that we have no additional information regarding the nuclear power plants in Japan apart from what we get through the media and we can therefore only talk about the issue on a general level.

As mentioned in the media, the threat is only related to Japan today. The next days will be critical and hopefully the work to cool the reactors will be successful so that the radioactivity will be limited.

If the action taken in Japan proves to be insufficient, the radioactive isotopes of greatest concern are Iodine-131 and Caesium-137. Iodine-131 has a half-life of 8 days, meaning half of it will have decayed after 8 days, and half of that in another 8 days, etc. Therefore, it is of greatest concern in the days and weeks following an accident. If a person is exposed to iodine, it will be concentrated in the thyroid. The purpose of the iodine tablets is to block the thyroid and allow the iodine to spread around the whole body and then naturally pass out of the body without giving a concentrated radiation dose to a single vital organ.

With a half-life of about 30 years, Caesium-137 will take more than a century to decay in a significant amount. It is known to cause many different types of cancer.

There are mainly two ways to get contaminated either by food or via airborne contamination. Airborne contamination is direct and difficult to avoid while food is more long term and possible to measure and avoid.

It is possible to filter both Iodine-131 and Caesium-137. Iodine exists in both particle and gas phases but mostly as a gas. It is therefore necessary to use specific activated carbon for the gas and HEPA filters for the particles. Caesium-137 is a particle and therefore HEPA filters can be used to filter it.

Camfil Farr would like to point out that normal air handling units are not designed to deal with these isotopes and just replacing filters would only protect a building from contamination to some extent.


(19) 3847-8810 sac@camfil.com

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