Radioactivity in the United States from Japanese Nuclear Plants

No, there is no need for concern. The information we have now tells us that no harmful levels¹ of radioactivity will arrive in the United States from the failed Japanese nuclear power plants. Radioactive plumes² that are being generated are dissipating with time as they cross the vastness of the Pacific Ocean.

In spite of this reassurance, thousands of people are purchasing potassium iodide (KI), a substance that blocks radioactive iodine (which may be in the plumes and is a potential cause of cancer) from accumulating in the thyroid gland. Medical experts state that there is no need for that in the United States. In fact, use of KI could have an adverse medical effect on people with specific allergies and other ailments.

The U.S. Environmental Protection Agency (EPA) is working with its federal partners to place additional monitors (like air-sampling equipment) in parts of the United States and in the U.S. Pacific territories. The EPA states that it has made this decision "out of an abundance of caution"³ and it is expected that the monitors will show no harmful levels of radiation reaching the United States from Japan.

For more information on the Japanese nuclear reactors, see our Fukushima section on our Health Physics Society Website.

For more information on radiation, see Radiation Answers.

Radioactivity (or radioactive material) comes from the nuclear fuel in the plants. We call the radioactive compounds that are being released fission products. They include a number of radioactive noble gases, radioactive isotopes of iodine, and radioactive isotopes of other elements such as cesium.

Some of these materials emit radiation (gamma and beta rays) and, if in the surrounding air or deposited on the ground or other surface, can irradiate our bodies from the outside (externally).

In addition, if these materials are taken into the body by breathing or in food they have the potential of exposing body cells internally.

Geiger counters and other radiation-detection instruments are sensitive enough to detect radiation if you have as few as 50 to several hundred radioactive atoms on your skin. We know from detector readings that some of the evacuated residents and plant workers had some radioactive contamination on their clothing, but we do not yet have validated data on the level of radiation exposure to the individuals wearing the clothing.

Yes, from many sources. Our bodies contain some naturally radioactive potassium; our environment contains some naturally occurring radioactivity like uranium, radium, and radon; and there are consumer products containing radioactive materials, including smoke detectors, antique pottery called Fiesta ware, and some lantern mantles (typically used in lanterns when camping). If you want more information on radioactivity in consumer products, take a look at http://hps.org/publicinformation/ate/faqs/consumerproducts.html.