7 Things That Cause Lung Cancer That Aren’t Smoking

Updated: Mar. 07, 2022

You could get lung cancer even if you've never picked up a cigarette. Here are the common things besides smoking that can cause the disease.

No smoking gun

The deadliest cancer in the United States is lung cancer: It’s responsible for about 140,000 deaths each year. Even though smoking increases the risk of the disease more than anything else, 10 to 20 percent of lung cancer cases in the United States occur in people who have never smoked. “We think that [rate] is increasing as fewer people smoke,” says Heather Wakelee, MD, a professor of medicine at Stanford University Medical Center.

In some cases, things in the environment, especially radon and secondhand smoke, can be linked to lung cancer in people who aren’t smokers. “[But] the fact is, for the majority of [people who never smoked] we don’t know why they get it,” Dr. Wakelee says. These are 7 signs of lung cancer you might be ignoring.

radon gas
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Few people appreciate the risk of radon. Every year in the US, it causes about 2,900 lung cancer deaths among people who never smoked, according to the Environmental Protection Agency (EPA). It is responsible for about another 18,000 deaths among people who smoke or used to smoke. Those cases would probably not have occurred if the smokers hadn’t also been exposed to radon—a radioactive invisible gas released from certain types of soil. It makes smoking much more dangerous (and vice versa), says Bill Field, PhD, an occupational and environmental health professor at the University of Iowa.

Radon can seep into your home and accumulate. Testing, which numerous medical and environmental groups recommend, is the only way to know your radon exposure. You can learn all about radon testing here. Fortunately, do-it-yourself testing kits are cheap ($15-$25) and it is pretty straightforward to reduce the levels if they are high (having a vent pipe system installed). “Exposures can come from your workplace, schools and other buildings where you spend a lot of time,” so you should make sure those are tested too, Dr. Field says.

Secondhand Smoke
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Secondhand smoke

Being around people who smoke exposes you to the same cancer-causing substances in cigarettes, though the dose is lower than if you were inhaling yourself, Dr. Wakelee notes. The Centers for Disease Control and Prevention estimates that secondhand smoke increases the risk of developing lung cancer by 20 to 30 percent, whereas women and men who smoke are 13 and 23 times more likely to get lung cancer, respectively.

It can be difficult to avoid secondhand smoke if you live with someone who lights up. “For [your] own health, try to have conversations with that person…and make sure the person only smokes outside,” Dr. Wakelee says. And share with these 22 tips on how to stop smoking for good.

car emissions lung cancer causes
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Air pollution

Research studies suggest that air pollution, especially fine particles such as PM2.5 produced by car exhaust, power plants, and wildfires, can drive up the risk of lung, breast, and other cancers. A lot of this research has been done in China, but high levels of pollution also occur in the United States and can increase the chance of getting lung cancer, not to mention acute health problems such as asthma, says Charles Powell, MD, a professor of medicine and system chief of the Division of Pulmonary, Critical Care and Sleep Medicine at Mt. Sinai. Dr. Powell recommends keeping an eye on the air quality near you and staying inside if it’s bad. Here are 9 scary things air pollution does to your body.

Asbestos lung cancer causes


Groups such as the American Cancer Society list asbestos as one of the things that increase your chances of getting lung cancer. But this health effect “requires long-term high-intensity exposure…and that is typically found only in individuals with occupational exposure,” Dr. Powell says. People working in construction, demolition, car repair, and the military are at the highest risk of asbestos exposure because the material has been used in buildings and brake linings. Fortunately, it is less widespread since most asbestos-containing products have been banned or restricted in the United States since 1989, reports the EPA.

COPD Ribbon


Chronic obstructive pulmonary disease or COPD, a group of lung diseases that includes chronic bronchitis and emphysema, increases the risk of getting lung cancer. Part of the reason for the link is that lung cancer and COPD share similar risk factors, such as smoking and radon or asbestos exposure. A lifetime of smoking may be the biggest contributor to COPD: People who qualify as “never smokers”—they’ve smoked fewer than 100 cigarettes in their life—only get COPD under “extreme situations”, says Stanford’s Dr. Wakelee.

However, having a history of smoking does not seem to fully explain the connection between COPD and lung cancer; the inflammation associated with COPD probably also drives up lung cancer risk, Dr. Powell says. People with COPD should try to quit smoking if they still smoke and see if they qualify for low-dose CT lung cancer screening, he adds. Here are 7 silent signs you could have COPD and not know it.

Take out health insurance for family. Stethoscope, paper heart and silhouette of family on grey background top view
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Family history

People with a family history of lung cancer are at higher risk for the disease, especially if they have a close relative who developed the cancer at a young age. There is no genetic test available—as there is for breast cancer—because scientists have yet to determine a gene that is responsible for the disease, Dr. Powell says.

He recommends those with a family history talk with their doctor about low-dose CT lung cancer screening. Although the test is only recommended for current or former smokers, they may be candidates for the test. Here are 6 smart habits that can prevent lung cancer.

vaping lung cancer causes
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Vaping is not the safer alternative to cigarette smoking people claim. Even though the dangers are becoming more apparent, vaping is still popular—even among teens: 1 in 4 high school students report vaping or using electronic cigarettes in the last 30 days, reports the National Institutes of Health. “[This] almost certainly has a very high probability of leading to an increase in the number of lung cancer deaths that will occur as these kids age,” Dr. Powell says. The CDC has been tracking an outbreak of lung disease (2,051 so far) and deaths (39) linked to vaping, and research has shown that lung disease can lead to an increase in lung cancer risk, he adds. Here are 9 urgent reasons to stop vaping right now.