An analysis of more than 700 counties across the U.S. has uncovered a connection between childhood leukemia and exposure to radon gas, even at levels below federal guidelines for mitigation.
The research, led by researchers at Oregon State University, suggests that radon may pose broader health risks than previously understood, particularly for children.
Radon is a naturally occurring radioactive gas produced from the decay of uranium found in rocks and soils. While generally harmless outdoors, radon can accumulate indoors, becoming a significant health hazard.
It has long been recognized as a leading cause of lung cancer, responsible for between 3 and 14 percent of all lung cancers, according to the World Health Organization. However, it had not been linked to other forms of cancer—until now.
The 18-year statistical modeling study, published in Science of the Total Environment, analyzed data from 727 counties in 14 states, including Washington, California, and New York.
Researchers found a notable link between childhood leukemia and radon exposure, with elevated risks detected even at concentrations lower than the Environmental Protection Agency's (EPA) recommended threshold of 148 becquerels per cubic meter.
Becquerels are a standard unit of radioactivity, corresponding to the number of radioactive decays per second.
"This is the largest study of its kind in the U.S.," the study's lead author and assistant professor at Oregon State University's College of Health, Matthew Bozigar, said in a statement. "More robust research is necessary to confirm these findings on an individual level and inform decision-making about health risks from radon in this country and globally."
Leukemia, the most common cancer in children, affects the blood and bone marrow. Approximately 3,000 new cases of childhood leukemia are diagnosed annually in the U.S., according to the National Institutes of Health (NIH).
The disease's annual incidence rate stands at 4.8 cases per 100,000 children, with boys being more likely than girls to receive a diagnosis. However, the study found that radon exposure increased the likelihood of leukemia in both sexes.
Childhood leukemia has few known risk factors, and environmental influences remain poorly understood. Bozigar and his team are calling for further studies to explore whether radon directly causes childhood leukemia, though their current research only identifies statistical associations.
"Studies that can better determine whether radon exposure causes childhood leukemia are needed," Bozigar said.
Radon gas is odorless, tasteless, and colorless, making it difficult to detect without special equipment. Measured with passive detectors, it can be mitigated through ventilation in basements and crawl spaces.
The EPA warns that no level of radon is completely safe, advising mitigation when concentrations exceed the 148-becquerel threshold. The research considered levels as low as half that amount.
However, Bozigar doesn't think the guidelines should be changed just yet.
"Because our study adds evidence in the U.S. and adds to a relatively larger body of research in Europe on radon and non-lung cancers that increasingly link radon to childhood leukemia, my suggestion to the EPA is to incentivize research on the potentially wide health effects of radon gas decay," he told Newsweek.
"I think additional evidence, particularly in the U.S., will inform the EPA in its decision-making going forward."
A spokesperson for the EPA told Newsweek the agency is "analyzing this study report, as well as other emerging research, as it continues to promote radon testing in homes, schools, and other buildings, mitigation of elevated radon levels, and the construction of new homes and schools to be radon-resistant."
They added, "At this time, the agency has no plans to lower its recommended indoor radon action level of 4pCi/L."
Bozigar, who grew up in Portland—an area known for high radon levels—was personally motivated to study the gas after observing a seemingly high rate of cancer among young people in his community.
"As an epidemiologist, I started considering possible environmental causes and connected with awesome collaborators who provided important data and other resources to enable innovative new analyses," he said.
"We are working on many different radon studies, and we are continuing to find harmful effects not limited to the lungs in adults. We will have more to share in the coming months and years as our studies are published."
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Reference
Bozigar, M., Konstantinoudis, G., Zilli Vieira, C. L., Li, L., Alwadi, Y., Jones, R. R., & Koutrakis, P. (2024). Domestic radon exposure and childhood cancer risk by site and sex in 727 counties in the United States, 2001–2018. Science of The Total Environment, 954. https://doi.org/10.1016/j.scitotenv.2024.176288
Update 10/01/24 12:37 p.m. ET: This article was updated with comment from Matthew Bozigar and an EPA spokesperson.
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