Which of the following is NOT a way radon may enter a house?

• A. Cracks in foundation
• B. Open crawl spaces
• C. Open attic vents
• D. Open openings around pipes

Answer: (C)

Radon enters homes primarily through openings that connect the indoor space to the soil surrounding the foundation. Cracks in the foundation and openings around pipes provide direct routes for soil gas to seep indoors, and open crawl spaces create a direct path from the ground into the living areas. An attic vent, however, sits high above the living spaces and is designed to vent the attic to the outdoors rather than serve as a conduit from soil into the home. Because radon originates in the soil and tends to move into lower parts of a building, attic vents do not represent a typical entry point.