CHICAGO As workers struggle to contain the fallout from the crippled nuclear plant in northeastern Japan, people as far away as Illinois are calling public health officials in a state of panic.
They are hoping to get their hands on potassium iodide pills to protect them from radiation -- despite warnings that, in the absence of a real nuclear threat, taking the medicine is riskier than doing nothing.
Sixty-six years after the first atomic bomb exploded over the city of Hiroshima, radiation spooks people everywhere. But the anxiety is largely disproportionate to the actual danger.
"People in general have an exaggerated fear of radiation. That is true in the United States, and it is probably even more so in Japan," said Jerrold Bushberg, director of health physics programs and clinical professor of radiology and radiation oncology at the University of California Davis.
Despite the Japanese government's assurances that the risk so far is minimal, residents of Tokyo have flooded out of the city and foreigners have fled the country, hoping to escape a threat they cannot see.
The fact is that everyone is exposed to small amounts of radiation every day just from living on earth or flying in an airplane. That all adds up to about 2.4 units, known as millisieverts, a year. This can vary widely, ranging from 1 to 10 millisieverts, depending on where you live.
Background radiation will cause 1 out of 100 people to die of cancer in their lifetimes, said Dr. Donald Bucklin, who spent 10 years as medical director for the Palo Verde nuclear plant in Arizona, the largest nuclear plant in the United States. Additional exposure increases this risk.
In Tokyo, 150 miles from the Fukushima Daiichi plant, people grew fearful when readings rose about 10 times above the normal reading. At that level, residents were exposed to 0.809 microsieverts per hour -- 1,000 times less than a millisievert, or about 10 times less than a chest X-ray.
"The levels of radiation experienced by the public at present should be no cause for concern," said Dr. Richard Wakeford, visiting professor of epidemiology at the Dalton Nuclear Institute at University of Manchester in Britain.
"To put radiation doses into context, many Japanese undergo CT scans for cancer screening purposes, and these scans produce radiation doses of about 10 millisieverts (10,000 microsieverts) -- much more than they are receiving from the Fukushima reactors."