Statistically you are more likely to die from radon exposure than a drunk driver. There’s a link between radon as a sole contributor and 21,000 US deaths per year. Radon is the 2nd leading cause of lung cancer deaths and 7th leading cause of total cancer deaths.
Open sump pits and other holes in the foundation can increase overall radon levels. Especially in the winter when the surrounding ground is frozen.
Radon is the 2nd leading cause of lung cancer in the United States. And the EPA recommends testing for radon in your home every two years.