Radon Gas Detector
Radon gas is not to be confused with the type of gas that may fuel your stove or home heating system. Gas stoves and heat rely on your utility company, which deliberately puts that sulfurous smell into your gas pipes. This smell enables you to tell if you have a gas leak, which enables you to evacuate your house (since gas leaks can cause explosions) and call the utility company immediately. Radon, on the other hand, can kill you silently. You may not even be aware of exposure until years later, when the damage finally becomes evident. It builds up over time without causing immediately noticeable symptoms.
Radon gas is a naturally occurring, odorless gas. Radon exposure can lead to lung cancer (and is the leading contributor to lung cancer deaths among nonsmokers) but the only way to tell if it's present is with a radon gas detector. Radon is present in all parts of the country, often at harmless levels, but there's no way to tell for sure without testing. Even houses near each other may have very different radon levels. If a radon gas detector finds that your house has a problem you can have a radon mitigation system installed (this usually involves a pipe that vents from your foundation to the outside with a fan, designed to pull radon into the surrounding air rather than build up in your home).
Radon gas detectors are easy to acquire and use. It's important to follow the instructions carefully. Generally, you'll have to send the radon gas detector kit back to a lab for a reading by a professional, and the results are mailed back to you. The entire process can take a few weeks, so be sure to allow for this if you are buying or selling a home.