Radon causes cancer when the radon decay product is inhaled and becomes deeply lodged in the lungs. These particles radiate and can penetrate bronchial cells, mucous membranes, and other lung tissues.
The carcinogenesis process is believed to begin from the ionizing radiation energy affecting the bronchial cells. Radon-related lung cancers are generally seen in the upper airways, but radon increases the frequency of all types of lung cancer, including: Adenocarcinoma, Small Cell Carcinoma, and Squamous Cell Carcinoma.
Lung cancer resulting from breathing in radon decay products is the only known risk associated with radon. Smoking tobacco multiplies the risk of radon-induced lung cancer by an average of 10 times.
According to the Minnesota Department of Health, every 25 minutes, a person in the U.S. dies from radon-related lung cancer. It is the leading environmental cause of cancer deaths and the leading cause of lung cancer among non-smokers.