First of all, let’s define carcinogen. A carcinogen is any substance that has proven to cause cancer in living tissue. Radon is widely classified as cancerous by several authorities on public health. Some of these organizations include the U.S. Department of Health and Human Services, the EPA, the Centers for Disease Control, the World Health Organization and the National Academy of Sciences.

The greatest risk comes from long-term exposure. Miners became one of the researchers’ favorite test subjects because they were exposed to radon for extended periods of time. Researchers learned that extended exposure to radon levels over 4 pCi/L in a home may pose a similar risk. Thankfully, homes are easily tested and protected from radon.