Exposure to radioactive emissions from radon in uranium mines has been shown to be responsible for the increased risk of lung cancer among miners. Recent concern has focused on radon exposures in homes, particularly those that have been made air-tight by efficient insulation. Radon can enter the home from soil, water, or building materials. The Environmental Protection Agency has suggested that homes with indoor radon levels above 4 picocuries per liter be subject to modifications, although others recommend consideration of remediation only at levels of 5 to 10 picocuries per liter or higher. Lowering indoor radon in this way would protect the persons at greatest risk.
Cigarette smoking is a well-established cause of a number of cancers.