RADIATION SAFETY

Where does radiation come from?
Radiation occurs every day naturally or in man-made forms.  We are exposed to radiation from natural sources all the time. The average person in the U.S. receives an effective dose of about 3 millisievert (mSv) per year from naturally occurring radioactive materials and cosmic radiation from outer space. These natural "background" doses vary throughout the country.  In 1992, the average dose received by nuclear power workers in the United States was 300 millirem (mrem) whole body equivalents in addition to their background dose.

People living in the plateaus of Colorado or New Mexico receive about 1.5 mSv more per year than those living near sea level. The added dose from cosmic rays during a coast-to-coast round trip flight in a commercial airplane is about 0.03 mSv. Altitude plays a big role, but the largest source of background radiation comes from radon gas in our homes (about 2 mSv per year). Like other sources of background radiation, exposure to radon varies widely from one part of the country to another. (Source)