Radon is a naturally occurring radioactive gas that you can't see, taste, or smell. Radon is the second leading cause of lung cancer in the United States resulting in approximately 20,000 deaths annually. There is no truly "safe" level of radon; however the risk decreases as the radon concentration decreases.
The only way to know if you have high levels of radon is to have your home tested. Testing is easy, inexpensive, and high levels of radon can be fixed. Princeton as a municipality ranks as a Tier 1 radon potential, see Radiation Protection Element website. This means there is a high radon potential for homes in Princeton.
Radon Test Kits - Test by Mail
Radon test kits are available through a number of New Jersey Department of Environmental Protection certified radon measurement businesses. These privately operated companies will send a test kit to your home to be run and returned for analysis. A testing fee is associated with the kit, with instructions for payment inside of the packaging. See NJDEP Certified Radon Measurement Companies list to find a service provider to assist with testing.
Businesses engaged in addressing radon in New Jersey are required to be licensed by the New Jersey Department of Environmental Protection. While Princeton does not recommend any one service provider over another, see NJDEP Certified Radon Mitigation Businesses list to confirm any company being consulted is properly certified for the work.