Per The Pennsylvania Department of Environmental Protection regarding radon:

Radon is an odorless, invisible, radioactive gas that can enter your home from the ground through cracks in the foundation. A known human carcinogen, radon is the second leading cause of lung cancer.

Pennsylvania has one of the most serious radon problems in the United States. Approximately 40 percent of Pennsylvania homes have radon levels above Environmental Protection Agency's action guideline of 4 picocuries per liter. 

You can search for radon test data by zip code, but hands down, the smartest thing to do is to test your home for radon, no matter where you live. Protect yourself and your loved ones: Do a home radon test.

Harrisburg Home Inspections: We Can Help:

Central PA is among the “Highest Potential” for radon in the State.  Have a Radon test done by HouseMaster Harrisburg/Lebanon.  We can do a radon inspection at the time of a Home Inspection or as a stand-alone radon service.