Radiation is a natural part of our environment.
The average American receives radiation exposure of about 620 millirem (mrem) annually from all sources, according to the National Council on Radiation Protection and Measurements. About 50% of that exposure comes from naturally occurring radiation from the earth, in the air and water, from outer space and in our own bodies.
Nearly 310 mrem each year comes from man-made sources, such as medical and dental X-rays and certain consumer products. For example, a chest X-ray is about 10 mrem and a CAT scan is about 1,000 mrem or more. One round-trip flight from New York City to Los Angeles provides between 2 mrem and 5 mrem.
By comparison, public exposure to radiation from the entire nuclear energy fuel cycle is 0.4 mrem per year. The average nuclear plant worker receives 160 mrem annually.
In numerous health studies over the past 60 years, the risk of health effects from exposure to low levels of radiation is small. Low level radiation exposure is defined as anything below 10,000 mrem.