by Sarah Craighead Dedmon

What’s invisible, odorless, and a leading cause of lung cancer? You guessed it — radon, a radioactive gas that seeps out of bedrock, entering buildings through basements or even slab foundations.

“Some of the highest readings I’ve gotten are homes that are on slabs,” says Alan Gardner, owner of Tri County Radon in Machiasport, which offers air and water radon testing services for homes, businesses, and schools.