Radon — an odorless, colorless gas that seeps from uranium in the soil — accounts for more than half of the ionizing radiation most people encounter in their lives. When inhaled, this radioactive gas can set the stage for lung cancer.
Much as researchers use atomic blasts to estimate the risks of CT scans and X-rays, they use cancer rates of uranium miners to calculate the toll from radon. Although nobody’s basement has as much radon as a uranium mine, it’s estimated that 20,000 Americans die of lung cancer from radon exposure each year, says R. William Field, a professor of occupational and environmental health at the University of Iowa in Iowa City. By comparison, smoking is thought to cause more than 130,000 lung cancer deaths each year.