In the discourse around lung cancer prevention, clinicians are well-versed in talking with their patients about smoking history. But Clifford Mitchell, MD, MPH, explains how a conversation about radon testing can be just as vital—and just as straightforward.
“Of the factors we know about lung cancer, the top two are controllable,” said Dr. Mitchell, Director of the Environmental Health Bureau at the Maryland Department of Health. “Number 1 is tobacco, and number 2 is radon.”
“We as physicians have focused a lot on developing effective cancer treatment. We’ve made progress in cancer screening with advances in medical imaging and other approaches,” said Dr. Mitchell, who served on the faculty at the Johns Hopkins Bloomberg School of Public Health before joining the state health department in 2006.
“At the same time, we’ve known about the risks of lung cancer associated with tobacco. And we’ve also known—frankly, for a long time—about the hazards of radon-related lung cancer risk.”
The very next question
While the hazards of radon aren’t a new discovery, the challenge is getting clinicians to consistently talk to patients about why it’s important to test their homes for this radioactive gas. A patient’s risk is particularly increased if they smoke and have radon in their homes, Dr. Mitchell said.
“Just as you routinely ask your patients, ‘Do you smoke? Have you ever smoked?’ the very next question you should ask is, ‘Have you tested your home for radon?’” he said.
As a colorless, odorless gas, radon is a long-term hazard that’s easily ignored. But the effects of chronic exposure can be devastating: It’s the second-leading cause of lung cancer and the No. 1 cause among people who don’t smoke, contributing to an estimated 21,000 lung cancer deaths each year in the United States alone.1
“If you don’t smoke, and there’s nobody in your household who smokes, you’ve done the most important thing that you and your family can do to prevent lung cancer,” Dr. Mitchell said. But the message he wants to drive home for patients is this: “On the other hand, we know that lung cancer occurs in people who’ve never smoked in their lives. There are many possible reasons for that, but the next most important preventable exposure—for you, your children, your grandchildren, and anyone in the household—is radon.”
Clinicians can also confidently recommend the next steps for testing. Test kits are available for $10 to $30 online, at local hardware stores, or through state and local health departments.
When to test
Socioeconomic factors are certainly in play when it comes to the public’s options for resources and housing. For example, someone purchasing a home may include radon testing as part of the inspection process, while a renter’s landlord isn’t necessarily mandated to test the property.2
Ultimately, risk level boils down to geology, Dr. Mitchell said.
“For example, here in Maryland, we have sort of three major geologic features,” he said. “We’ve got the sandy soils of the Atlantic coast and the Chesapeake. Then we’ve got the relative plateau of the Piedmont area, and then we have the Appalachians. The sandy soils of the coast tend to be relatively low in the kinds of geology that produce radon. By contrast, in the Piedmont area in the middle of the state, there is a belt of strata that produce significantly elevated levels of radon in a way that can permeate up into the soil and in through the slab of the home.”
Radon is heavier than the atmosphere, so ground-level and basement structures are closer to potential exposure areas while apartments and condos on higher floors carry minimal risk, Dr. Mitchell explained. Then there are structural features of the building itself that can make a difference in whether radon can easily permeate the home. New construction can alter the foundation slab, adding a sump pump can stir up the surrounding soil, and a crack in the slab can provide a point of entry.
“That’s one of the reasons we encourage people, no matter where they are, to test. And if they do major structural work, or if around five years’ time has passed, they should retest,” Dr. Mitchell said.
From awareness to action
Pulmonary clinicians understand the risks of tobacco and radon, particularly when discussing lung cancer cases, but in some respects, it’s more important to get people to think about radon before they have lung cancer, Dr. Mitchell said.
“It would make me very happy if pulmonologists seeing their patients with asthma or with COPD or with practically any pulmonary disease would routinely ask them about radon, because it is a cumulative risk over a very long period of time. We want to get people thinking about radon and then say, ‘You know what? Maybe I’ll just go do that test today.’”
In the course of his work with the Maryland Department of Health, Dr. Mitchell collaborates closely with local health departments and with the US Environmental Protection Agency, which has historically provided funding to individual states to help increase radon awareness. He’s found that one of the most effective outreach strategies is to have volunteers tell their stories.
“We have had people come forward who [never smoked] and they unfortunately developed lung cancer. They talked about their experiences and how they wish they had known about radon and the ability to test for it, because they discovered that they lived in an area that had high radon levels,” Dr. Mitchell said.
The Maryland Department of the Environment uses these stories to spread information to the public. For example, Jackie Nixon lived a healthy life as a person who did not smoke, exercised regularly, and had no family history of the disease; so when her doctor told her he had no idea how she contracted cancer, it was devastating. It took a home inspector to bring up the question of radon. The personal testimony of Ms. Nixon is available on the department’s YouTube page. These testimonials can help spark a conversation between clinicians and their patients, Dr. Mitchell said.
“Those volunteers have been some of our biggest advocates and our most effective spokespeople. You can’t replace the power of those stories.”
This article was adapted from the latest issue of CHEST Advocates—all about lung cancer prevention, research, inequities, and stories. Engage with other content from this issue on the CHEST website.
References
1. Health risk of radon. United States Environmental Protection Agency. Updated June 24, 2026.
2. Walsh J. Maryland landlord radon testing rules: what renters need to know. Tenant Rights USA. Published March 9, 2026.
