Which of the following is true about radon gas?

Radon gas is an odorless and colorless gas that is produced naturally from the decay of uranium in the soil, rock, and water. Because it is both invisible and has no scent, individuals exposed to radon may not be aware of its presence unless they conduct testing. Radon is known to pose serious health risks, as long-term exposure to high levels can lead to lung cancer. This is supported by studies indicating that radon is the second leading cause of lung cancer after smoking. Thus, recognizing the hazardous nature of radon, especially in enclosed spaces like homes, is crucial for health safety.

In contrast, the other statements are inaccurate because radon does not have a noticeable smell, is not easily identifiable without testing, and low levels may not be considered completely harmless since even minor amounts can contribute to long-term exposure risks. Understanding the true nature of radon is vital for real estate professionals and homeowners alike, highlighting the importance of radon testing in certain areas.