The highest level of radon ever recorded in Pennsylvania was found in a newly constructed house in Center Valley, the state Department of Environmental Protection said Thursday.
In October, a reading of the carcinogen showed a level of 6,176 picocuries per liter, more than 1,500 times higher than the recommended limit of 4 pCi/L set by the U.S. Environmental Protection Agency.
It's against DEP policy to release the exact location of the property, but spokeswoman Colleen Connolly confirmed it is in the same area of Upper Saucon Township where extremely high levels were found in 2014 — a discovery that prompted DEP to send 500 letters to nearby residents and hold a town hall meeting urging them to test their homes.
The most recent reading is more than double the highest level recorded in 2014, when the DEP announced a number of Center Valley homes were found to have radon levels greater than 1,000 pCi/L. At that time, the highest reading was 2,750 pCi/L.
The DEP does not have any plans to send letters or hold another town hall meeting, Connolly said Wednesday. Radon testing is not required in Pennsylvania and there are no guidelines requiring a homeowner to notify the DEP if a high reading is taken. However, many homes are tested when they are sold and owners will notify the department if an unusually high level is found, Connolly said.
Radon is a colorless, odorless, radioactive gas that occurs naturally through the breakdown of uranium in soil and rocks. It can enter a home through cracks in the foundation or other openings. Homeowners whose homes have levels higher than 4 pCi/L are urged to install a radon mitigation system.
The National Toxicology Program, comprising the National Institutes of Health, Centers for Disease Control and Prevention, and Food and Drug Administration, classifies radon as a known human carcinogen. Scientists estimate that about 20,000 lung cancer deaths yearly are related to radon. It's the leading cause of lung cancer in nonsmokers and second-leading cause in smokers.
For a typical home, a mitigation system can cost between $1,000 to $1,200, said Bill Brodhead, whose company, WPB Enterprises, has been installing radon mitigation systems in homes since 1982. Brodhead says the 6,176 pCi/L reading is the highest he's ever heard of and believes it could even be among the highest ever recorded in the country.
"There are three reasons for radon: location, location, location," Brodhead said. "It didn't happen because of how they built the house, it just happens because of where the house is built."
Because of its geology, Pennsylvania is prone to high radon levels. Radon has been detected in all 67 counties, and about 40 percent of homes in the state have levels above EPA's action level.
The area where the recent reading was taken is near the Reading Prong, a geological section of granite that historically has generated high levels of radon, DEP officials said.
Brodhead believes all new homes should be constructed with radon mitigation systems, though he says many Pennsylvania municipalities do not require them.
A mitigation system often includes installing pipes into the rock under the home. The pipes carry the gas out and vent it through the roof of the home. For homes with especially high levels, a fan is installed to facilitate the process, Brodhead explained.
When the high radon levels were discovered in Center Valley in 2014, Southern Lehigh School District officials said they had radon mitigation systems in four buildings: the high school, district office, a small ranch house that was formerly the earned income tax office, and Lower Milford Elementary school, which has since closed.
Those buildings were tested and found to meet state radon standards. School officials at the time said radon testing is done every three to five years.
Testing is the only way to know if a home, school, workplace or other structure has elevated levels of radon. An easy home test kit can be bought at hardware or home improvement stores for about $20 to $30. People may also hire a state-certified testing company.
DEP certifies all radon testers, mitigators and laboratories doing business in the state to ensure reliable results.