Mono County has radon levels higher than the California average, and some homes have very high levels. Radon is a natural radioactive gas from the earth which can accumulate in buildings, and long-term exposure can cause lung cancer. Radon is tasteless, odorless and invisible, and it is considered the second leading cause of lung cancer in the United States, after cigarette smoking. The risk of lung cancer from radon exposure is greatly increased in people who smoke. 

Radon gas is formed in the earth and moves to the surface where it enters the atmosphere. Outdoors it poses no risk, but it often passes from the soil into buildings and accumulates indoors, leading to potentially unsafe levels. The gas passes through concrete and numerous other materials. It is heavier than air so it accumulates in the lower levels of buildings (like basements, crawl spaces, and ground floor areas). Radon levels often vary from house to house within the same neighborhood. That’s why the U.S. Environmental Protection Agency (EPA) recommends that everyone test their home radon levels, and take steps to lower the levels if necessary. This may be especially worthwhile in areas like the Eastern Sierra where the geology, soil, and rocks have the potential to produce unsafe indoor radon levels. 

There is no safe level of radon.  However, the EPA recommends fixing your home if radon levels are 4 picocuries per literLiter (pCi/L) or higher. Simple and inexpensive tests are available here [1] through a program supported by the State of California, and free tests are available from Mono County Public Health offices (Mammoth Civic Center/Bridgeport). Radon test kits will also soon be available in the free health vending machines at the Mammoth Library and Latin Market 2 in Chalfant. If you find your home has high levels of radon, it is generally considered best to enlist the services of a certified radon mitigation contractor. There are various ways to reduce radon to safe levels in the home, with ventilation of the home or the soil beneath the structure often the best approach. Installation of plastic barriers over the foundation are also sometimes a good option. A list of certified radon service providers can be found here [2]. Unfortunately, we are not aware of active certified radon service providers in Mono or Inyo Counties at this time. If you are a radon mitigation contractor in our area, please let us know! It is recommended that real estate inspections include radon testing, but this is not routine. Prospective buyers may request this. State law does require that sellers disclose known elevated radon levels in real estate transactions.