A report recently released by the President's Cancer Panel focuses on underestimated cancer risks related to environmental contaminants and other harmful exposures, including radon. The report, "Reducing Environmental Cancer Risk: What We Can Do Now," notes that "the cancer risk attributable to residential radon exposure has been clearly demonstrated and must be better addressed." "This report has some of the strongest worded recommendations yet in regard to radon," said R. William Field, University of Iowa professor of occupational and environmental health and epidemiology. "Radon is likely our leading environmental cause of cancer mortality in the United States. During the past 50 years, over a million people have died nationwide from radon-related lung cancer." Radon, a radioactive, invisible, odorless gas that comes from the decay of naturally occurring uranium in the earth's soil, can accumulate in enclosed areas, such as underground mines and homes. It is the second leading cause of lung cancer in the United States and the leading cause of lung cancer among people who have never smoked, according to the report. In 2008, Field testified before the President's Cancer Panel regarding environmental factors in cancer. At that meeting he discussed ever-increasing exposure to radon due to new homes being built without radon-resistant features faster than existing homes are mitigated to reduce radon. "We need to go beyond voluntary radon mitigation programs," Field said. "Mitigating existing houses for radon is two to three times more expensive than building radon-resistant homes in the first place." The panel's new recommendations include changing building codes to require radon reduction features in new construction and implementing tax deductions or other incentives to encourage radon mitigation of current housing. The panel also advises regular testing of all schools, day care centers and work places for radon levels and mitigating those found to exceed the Environmental Protection Agency's (EPA) radon action level of 4 pCi/L. For individuals, the panel recommends homeowners periodically check their homes for radon levels and for homebuyers to conduct a radon test in any home they are considering buying. The panel also encourages the EPA to consider lowering its current "action level" (the level at which remedial action is recommended) of 4 pCi/L for radon exposure, given that new radon risk data have emerged since the existing action level was set. In 2009, the World Health Organization set a new recommended radon reference level of 2.7 pCi/L for residential structures. "Radon-induced lung cancer is responsible for an estimated average of 21,000 deaths annually in the United States," Field said. "The President's Cancer Panel has thoughtfully reviewed the scientific evidence in regard to radon and many other environmental toxicants and has issued a call to action that should not be ignored." The complete President's Cancer Panel report can be viewed online here. Also available are selected presentations to the President's Cancer Panel published in "Reviews on Environmental Health," guest edited by Field see here.