Map of North Carolina illustrating areas with high radon readings.
Map of North Carolina illustrating areas with high radon readings in 2017. Map courtesy NC DHHS

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By Catherine Clabby

It’s winter, so public health advocates once again are urging North Carolinians to test their homes for radon contamination.

There is good reason to listen up.

Unlike some states, North Carolina does not require builders to use construction techniques known to shield homes from radon, a known cause of lung cancer. So people dwelling in new and older untested structures remain at risk here.


Radon gas can seep into a home through: cracks or gaps in floors, construction joints, cracks in walls, gaps around pipes, cavities in walls, contaminated well water. Source: EPA

Invisible, odorless and cancer-causing, radon gas has been found in homes, even schools, across this state, with structures in western and some central counties at particular risk due to the geology beneath them.

“You can have radon in any home. The only way to know for sure is to test,” said Catherine Rosfjord, a branch manager in the Radiation Protection Section of the North Carolina Department of Health and Human Services.

County and state health programs, as well as NC State Extension, take pains, especially in winter when people are indoors, to warn about this stealth risk and urge people to avoid fly-by-night help if they do detect the gas in their homes.

In January, county health departments began handing out free radon testing kits obtained from the state.

Guilford County health workers, when funding was available, have gone door to door. They’ve also tutored families with newborns about radon, offering them free kits and educational material about ways to protect a family.

Educators always stress that if a neighbor tapes a free test kit to a wall or fan blade and turns up no evidence of gas, that doesn’t mean everyone nearby is safe, said Paula Cox, an environmental health manager in Guilford.

“The Piedmont is really interesting because there are pockets where you can have high levels of radon and just down the road it’s fine,” Cox said.

Invisible risk

There is no preventing the production of radon gas but there are steps that shield structures and the people who dwell in them.

Radon gas occurs naturally, produced when uranium breaks down in rocks underground. North Carolina, particularly the Piedmont and Blue Ridge Mountain regions, sits atop gneiss, schist and granite, rock types with higher than average concentrations of uranium.

The EPA in 2003 estimated that radon causes about 21,000 lung cancer deaths per year. Below are the numbers of deaths attributed to other causes by the National Center for Injury Prevention and Control Report and National Safety Council Reports at that time. Source: EPA

Among non-smokers, radon is the leading cause of lung cancer in the United States. The EPA has estimated that radon exposure contributes to about 21,000 deaths each year.

Radon gas is dangerous because it decays into damaging, radioactive particles that can get trapped in people’s lungs. If concentration of the gas reaches above 4 pCi/L, steps should be taken to reduce the concentration, the EPA says. (A pCi is a measure of the rate of radioactive decay. One pCi is one trillionth of a Curie, 0.037 disintegrations per second.)

The North Carolina Radiation Protection office reviewed radon tests taken in 23,448 classrooms in 94 counties in the 1990s. The review indicated that approximately 11 percent of the classrooms tested had radon concentrations greater than 4 pCi/L.

Unregulated in NC

As of 2015, nine states required that new construction in at least some cases be made radon-resistant, according to the National Conference of State Legislatures. In 23 states, either state or local (county or municipal) rules require the same. Twenty five states require that radon inspectors and people hired to eliminate radon contamination be licensed.

Before selling a property, a North Carolina homeowner must disclose if radon has been detected at levels exceeding government safety standards at an address. But otherwise, state law doesn’t require government intervention in preventing or reducing radon exposure, Rosfjord said.

“There had been some effort to regulate the radon industry in terms of the people who test homes and mitigate [install protective piping] in homes. But we discovered we don’t have authority to regulate naturally occurring radiation,” Rosfjord said.

Health advocates here brief people on how to best proceed if testing with a low-cost kit like those handed out by counties turns up signs of trouble.

Unable to recommend any single company or person, the NC Radon Program urges people to seek out organizations that award radon testing certificates to find trained testers. If contamination is confirmed, and passive piping systems or piping with a fan to move the gas is required, the state program suggests hiring people certified for that work, too.

People who can’t afford the roughly $1,200 the protective construction work can cost are eligible for financial help in this state, either through subsidies or low-cost loans.

Click on the image to go to an interactive map of how radon levels have tested. Map courtesy NC DHHS

Rosfjord said her colleagues have been working in recent years to recruit the medical community to help them spread the word of health risks from radon.

One sign of success is the commitment to promoting radon testing and protection in homes, schools, workplaces and community buildings in the most recent North Carolina Comprehensive Cancer Control Plan, she said.

“On the health aspect we’re doing well,” she said. “Some other states are more active in creating building codes and getting schools tested.”

Catherine Clabby

Catherine Clabby (senior environmental reporter) is a writer and editor. A former senior editor at American Scientist magazine, Clabby won multiple awards reporting on science, medicine and higher education...