The First Alert RD1 Radon Gas Test Kit detects dangerous radon gas in your home, work, or institution. Radon is a naturally occurring gas that can cause lung cancer, and can be found in basements, drains, crawl spaces, and other areas below ground. Simple, safe, and easy to use, this radon testing kit includes everything you need for an initial screening, including lab fees (except NJ state tests). The test is listed with the EPA and takes two to four days to complete in your home. Results are available 3-5 business days after lab receipt. The radon testing kit also includes recommendations and next steps if the results are positive for radon, and is ideal for disaster preparedness. It is recommended for use only within the United States.