Experts say radiation is all around us -- from the rays of the sun to the granite beneath our feet.
A large percentage of our exposure to radiation comes from nature. And then there are the optional doses.
"The vast majority of man made radiation is self-elected from things we choose to have done like X-Rays and Cat Scans," said Charlie Zender, a UC Irvine professor.
Professor Zender says the average person is exposed to four millisieverts of radiation each year. How much is that? It's the equivalent of about ten Mammograms, or two Cat Scans.
By contrast, nuclear power workers can receive 12 times the radiation others receive.
Still, Zender said even those who work inside places like San Onofre would have to double their exposure to be at an increased risk of cancer.
Edison says it has seen no sign of increased radiation from a tubing leak that was detected in one of the San Onofre reactors earlier this week.
"We have sensors all over the plant and none of them detected anything," said Gil Alexander, Edison spokesman.
Zender suspected that if any radiation was released, it was less than a chest X-Ray, which he said is among the lowest measurable radiation sources people regularly encounter.
But radiation can come to us in unexpected ways. Zenger said potassium in our bones and carbon in our flesh also emit radiation.
In fact, Zenger said, sleeping next to someone adds the equivalent of eating one banana each day, neither of which are considered harmful.