Skip to main content

Radon Health Risk


Les Smith
800-723-6642 (800-RADONGAS)

Find a radon test kit

Radon is a Class A carcinogen, which means it is known to cause cancer in humans. It is the second leading cause of lung cancer in the United States resulting in approximately 21,000 lung cancer deaths each year. Only smoking causes more lung cancers.

The problem occurs when radon and radon decay products (RDPs) are inhaled. When radon is exhaled, many RDPs are also exhaled, but some of the RDPs stay trapped in the lungs. As they undergo radioactive decay, they emit alpha energy, and the alpha particles can strike sensitive lung tissue causing physical and/or chemical damage to the DNA. When alpha particles strike and damage a lung cell, the cell will either:

  • Die, which seems like a bad thing, but new cells are generated to replace dead cells;
  • Repair itself and heal; or
  • Try to repair itself but do so incorrectly, possibly leading to the body forming cancer cells.

Not everyone who breathes radon will develop lung cancer. Your risk is determined by how much radon is in your indoor environment, how much time you spend in that environment, and whether you ever smoked. The only known health effect of radon is an increased risk of lung cancer. Exposure to elevated radon levels does not result in any warning symptoms like headaches, nausea, fatigue, or skin rashes. The only way to know whether you are being exposed to elevated radon levels is to perform a radon test.

The following national and international organizations support testing for radon and taking steps to reduce elevated radon levels to minimize the chance of getting lung cancer:

  • American Lung Association
  • American Medical Association
  • Centers for Disease Control
  • Environmental Protection Agency
  • International Commission on Radiological Protection
  • National Academy of Science
  • National Council on Radiation Protection and Measurement
  • U.S. Surgeon General
  • World Health Organization

Additional health risk information is available in the U.S. EPA's Assessment of Risks from Radon in Homes and the National Research Council's consensus report titled The Health Effects of Exposure to Indoor Radon or the report summary.