I grew up in the northeast, Connecticut, where radon is a big issue. Bedrock is close to the surface and most homes have basements, providing exposure to this gas prevalent in decaying granite. Tahoe has a similar situation where decaying granite does give off radon. Although most homes here don;t have basements, radon can still build in poorly ventilated crawl spaces. I know of a couple of instances in Incline Village where radon tests came back showing higher readings, and the problems were remediated. Ventilation is the key, and it is important to test if you have any concerns, since exposure is dangerous especially over the long term.