Are Security Scanners Safe?

Scientists still dont know whether radiation scanners are completely safe to use on humans. This is despite months of public debate between the White House, the U.S. Food and Drug Administration, and independent scientists. Full-body scanners have been installed at many U.S. airports. The machines use either low-energy, millimeter wavelength radiation, which is harmless, or X-rays, which can potentially be hazardous. X-rays can ionize atoms or molecules, which can lead to cancerous changes in cells. In April, four scientists at the University of California, San Francisco, wrote a letter to the White House warning that the government may have underestimated the dosage of ionizing radiation delivered to a person's skin from a backscatter machine by one or two orders of magnitude.