State Report Shows Unsafe Radon Levels in Encino

Radon—a naturally occurring radioactive gas that has been linked to lung cancer—is seeping into homes throughout Encino, according to a report from the California Department of Health Services.

The annual report of radon tests taken in communities around the state shows unsafe levels throughout Encino and surrounding communities, including Studio City, Sherman Oaks, Canoga Park, Tarzana, Chatsworth, West Hills and Woodland Hills.

In Encino, a total of 491 tests have been conducted for radon, 82 of which exceeded the levels considered healthy by the U.S. Centers for Disease Control.

"It's not good and, yeah, people may be frightened to find out that there are high levels like that in their neighborhood," said the state health department's spokesman Ken August. "But maybe it will encourage people to get their homes tested."

Radiation from radon is measured in picocuries per liter. The federal Environmental Protection Agency recommends that homeowners whose residences test at two picocuries per liter (2pCi/L) or higher should take precautions to vent their homes and dissipate the radon levels. The California health department  advises such action for homes with levels of 4pCi/L or higher.

In the 91316 ZIP code, 62 out of 209 tests found concentrations of radon that exceeded levels considered healthy by the CDC. That's 30 percent—making 91316 a high radon potential area, according to the state health department report. In 91436, 20 of the 282 tests showed unsafe radon levels. That's about 7 percent—making 91436 a low radon potential area. 

Flaws in the System

Organizing the data by ZIP code is a convenient way for the public to understand how a community may be affected. But the organization of the report also has its weaknesses.

"The concern is that geology, including radon, does not follow ZIP code boundaries, so people could become complacent," said Matt Conens of the California health department. "That is why it is so important for each person to test his/her own home."

For instance, there could be only one house in a neighborhood with high radon levels. It all depends on how tight a home's floor is to the ground and if there is an active source of the gas directly underneath it.

"Radon in this area most likely comes from materials eroded from the hills that run along the southern edge of the San Fernando Valley. These hills contain marine sedimentary rocks that contain higher than background levels of naturally occurring uranium, which produces radon as a result of radioactive decay," said Conens.  "Sherman Oaks and Encino have [higher] radon potential [while] areas that are located farther away from the hills moving north into the Valley, such as Valley Village and North Hollywood, have very low radon potential."

The challenge of managing invisible environmental hazards has not made Encino less desirable to residents. "This is nothing new," said Encino Neighborhood Council member Glenn Bailey when asked to respond to the findings. 

Bailey acknowledged that his neighbors and fellow council members, while not happy about the challenges presented by the nearby hills, are aware that they must be cautious and monitor the situation.

The Danger

Radon can damage cells lining the lungs. It is the second-leading cause of lung cancer in the United States behind cigarette smoking. So a smoker living in a house with high radon levels faces a significantly higher cancer risk.

"In general, heavy radon exposure to smokers is like being in a uranium mine," said Dr. Thomas Mack, a professor of preventive medicine and pathology at USC.  "Your increase in risk [of cancer] is like 2,800 percent.  Smoking really affects it."

The estimated annual number of lung cancer deaths in the United States attributable to radon is about 21,000, according to the EPA.

What can you do?

"You need to ventilate," Michael Cantor of 20-20 Advanced Properties & Mold Inspections said. "If you are in a slab home, bore holes to the soil and pipe it ... through the concrete and up through the roof, and up there will be installed a fan that goes continuously. It can be solar powered, but must always be going."

Do-it-yourself radon test kits can be ordered online from the California Department of Public Health.  The tests start at $5. Professional assistance ranges from about $200 to $250.  If high radon levels are found, simple solutions include just keeping the home ventilated by opening windows or caulking basement floor cracks. Winter months are a good time to test because radon is at its highest concentration— when houses tend to be closed up more to stay warm.

Radon mitigation measures can range from about $2,500 to $5,000. 

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--Mike Szymanski and Julie Walmsley contributed to this report