Several national and international agencies study different substances in the environment to determine if they can cause cancer. (A substance that causes cancer or helps cancer grow is called a carcinogen.) The American Cancer Society looks to these organizations to evaluate the risks based on the available evidence.
Based on studies in people and studies done in the lab, several expert agencies have evaluated the cancer-causing potential of radon.
The International Agency for Research on Cancer (IARC) is part of the World Health Organization (WHO). One of its goals is to identify causes of cancer. Based on sufficient evidence that radon and its progeny can cause lung cancer, IARC classifies them as “carcinogenic to humans.”
The National Toxicology Program (NTP) is an interagency program of US government agencies, including the National Institutes of Health (NIH), the Centres for Disease Control and Prevention (CDC), and the Food and Drug Administration (FDA). The NTP has classified radon as “known to be a human carcinogen.”
The US Environmental Protection Agency (EPA) monitors the human health effects from exposure to various substances in the environment. The EPA lists radon as the second leading cause of lung cancer and the number one cause of lung cancer among people who don’t smoke.Radon is also thought to cause a significant number of lung cancer deaths each year among people who don’t smoke.
