WORCESTER, Mass. - A new report shows high levels of cancer-causing radon gas were detected in nearly 22% of Massachusetts homes.

Radon is a naturally occurring radioactive gas emitted from the ground. It is odorless, tasteless and colorless and can enter a home through cracks in floors, basement walls or foundations.

The American Lung Association's report said it's responsible for an estimated 21,000 lung cancer deaths every year and is the leading cause of lung cancer in people who have never smoked.

"Unless we're measuring for that you'll have no idea and unfortunately we also see no short term symptoms of radon” said Dan Fitzgerald of the American Lung Association. “But we can see over a long exposure with that increase levels that's where we're unfortunately seeing people develop lung cancer from the exposure to radon."

The American Lung Association has both short- and long-term radon tests people can buy on their sites. Depending on the results, you can decide the next steps, which could include installing a radon mitigation system.