“Radon is the number one cause of lung cancer among non-smokers, according to EPA estimates. Overall, radon is the second leading cause of lung cancer. Radon is responsible for about 21,000 lung cancer deaths every year. About 2,900 of these deaths occur among people who have never smoked. On January 13, 2005, Dr. Richard H. Carmona, the U.S. Surgeon General, issued a national health advisory on radon.”
World Health Organization’s international radon project
see https://www.epa.gov/radon/health-risk-radon
I’m not a big fan of either the EPA or the WHO, but occasionally they get something right - the tie between radon and lung cancer is well-accepted in the scientific community, especially among cancer epidemiologists. That doesn’t mean it’s absolutely, positively, nobody-will-ever-find-anything else true, but I wouldn’t bet against it.
About 2,900 of these deaths occur among people who have never smoked.
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Look at the low number, could be random.
Again, if you do some on radon and how they arrived at the regulations and implementation, you would shake your head.
but second leading cause sounds so lethal.