Levels of Exposure


At the bottom of the graph is the exposure received (approximately 0.1 mR per year) when sleeping next to another person. This results from the presence of natural radioactive isotopes within all of us. Since everything in our environment is radioactive to some degree, we incorporate natural radioactive isotopes into ourselves. Not only does this result in some exposure to us, but to those around us as well.

When flying in a plane, we are located at higher altitudes and consequently have less protection from the atmosphere against cosmic radiation. This exposure typically results in 0.5 mR exposure per hour of flight.

The most significant power plant accident in the history of the United States occurred at Three Mile Island. This resulted in a release of radioactive materials that exposed 2.1 million people within a 50 mile radius to approximately 1.5 mR. Some members of the public complained of excess bleeding and infections as a result. The other graphs in this series will illustrate that such complaints could not occur based on the radiation doses received.

Due to the carbon-14 in the natural gas that is used for heating an cooking, there is a resulting radiation exposure of approximately 2 mR per year.

Exposure related to consumer products lead to approximately 3.5 mR per year. Some common items that can be found to be radioactive are smoke detectors, Coleman lantern mantles, and Fiesta Ware. Lantern mantles can now be purchased that do not contain significant radioactive materials. These have a gold colored top rather than the usual blue. Fiesta Ware was produced by Corning and was colored with a uranium based paint. Now a collectors item, it was removed from the market because of fears that the paint might chip and be ingested. Similarly, some green bathroom tile can be found to contain radioactive materials. To produce a deeper color, some gemstones are exposed to an intense neutron flux. This type of exposure may result in the stone becoming mildly radioactive

Although atmospheric testing of nuclear weapons has been terminated, we still receive approximately 4.5 mR every year as a result of the years of testing.