Several hundred years ago, scientists observed the occurrence of lung disease in European miners, and this appeared to be cancer. Further research suggested that radon gas, which is present in rocks, soil, and water, can predispose humans to the development of lung cancer. Whereas cigarette smoking poses the greatest risk for this disease, radon gas also significantly worsens its likelihood .
Those who smoke and encounter excessive levels of radon gas have an even higher risk of lung cancer than individuals who have only one of those risks. Of those who do not smoke, radon is the primary cause of lung cancer. The relationship between radon exposure and this malignancy is linear. In other words, the larger the dose of radon is to a human, the greater the predisposition for disease [1, 2].