Date Published: 01/23/2020 [Source]
It's known as the silent killer for a reason: Every year, radon, a naturally occurring, invisible, odorless, radioactive gas, causes an estimated 21,000 lung cancer deaths in the United States. In North Carolina, officials with the state Department of Health and Human Services estimate that 435 residents will die from radon-related lung cancer in 2020.
In an effort to make people more aware of the dangers, the state is again giving away 3,000 radon test kits as part of National Radon Action Month. The kits can be requested by visiting the Department of Health and Human Services' Radiation Protection Section.
Radon comes from natural deposits of uranium in soil, rock and water. Radon gas is usually harmlessly dispersed in outdoor air. The problems arise when homes or other structures are built on top of radon-producing geological formations. As radon gas moves up through the soil, it can be drawn into a home through differences in air pressure. The gas is sucked inside through any openings in the foundation, basement floor or crawl space.
The U.S. Environmental Protection Agency estimates that one in 15 homes in this country has excessive levels of radon. High levels of radon have been detected in homes in all 100 North Carolina counties. It is most prevalent in the Blue Ridge Mountain region and in a band of four counties in the Piedmont — Warren, Franklin, Vance and Wake, where the gas is generated in large, subterranean granite formations.
Eight counties are considered most at risk — Alleghany, Buncombe, Rockingham, Cherokee, Henderson, Mitchell, Transylvania and Watauga. Those areas sit atop gneiss, schist and granite, rock types with higher than average concentrations of uranium.
Radon, along with radium and uranium, can also be found in well water. The major concern with a contaminated well is the formation of gasses caused by showering or other household uses, such as washing dishes or doing laundry, according to the Centers for Disease Control and Prevention.
In eastern Wake County, officials estimate that private wells for one in five homes contain excessive levels of radon, uranium or radium. Radium is a solid produced when uranium decays. During the decay process, alpha particles start to be emitted, turning the radium into radon gas.
Last year, Wake County officials mailed notices to 19,000 households that may be affected and urged them to get their wells tested. Shortly afterward, Johnston County also started warning residents with private wells of the possibility of radon contamination.
Based on a National Academy of Science report, the EPA estimates that radon in drinking water causes about 168 cancer deaths per year, 89 percent from lung cancer caused by breathing radon released to the indoor air from water and 11 percent from stomach cancer caused by consuming water containing radon.
In eastern Wake County, Kane said, soil and well water contamination from radon, uranium, and, to a lesser extent, radium, pose significant health threats. He urged people to get their wells tested. Testing is free for households with incomes up to 2.5 times the federal poverty level, about $64,375 for a family of four.
Radon gas in homes is measured in picocuries per liter of air, or pCi/l. The EPA has set a health advisory for radon at 4 pCi/l. At that level or above, the agency recommends corrective measures be taken to reduce exposure.
The N.C. DHHS says a radon level in a home between 2 and 4 pCi/L is considered a moderate risk for developing cancer and over 4 pCi/L is considered high risk.