Causes of Lung Cancer

Male patient with lung cancer coughing

There are several known causes of lung cancer, including smoking and exposure to asbestos, radon, silica and diesel exhaust. Below, Moffitt Cancer Center explores how each of these lung cancer causes contributes to the development of this disease.


Studies have repeatedly confirmed that smoking is the No. 1 cause of lung cancer, with approximately 90 percent of all lung cancers stemming from tobacco use (or secondhand exposure to someone else’s smoke). Whenever tobacco smoke (or another carcinogen) is introduced into the body, subtle damage can occur in the lung’s tissues. At first, the body may be able to repair this damage. However, as the damage accumulates, it can cause cancerous changes in the formerly healthy cells. Eventually, lung cancer can develop.

Many individual factors can play a role in whether a former smoker will develop lung cancer. For instance, smokers who consumed one pack of cigarettes per day for 20 years, or two packs a day for 10 years, etc., will have a higher risk of developing lung cancer than smokers who consumed a few individual cigarettes per day for a shorter period of time.

Does marijuana cause lung cancer?

Although it’s well known that smoking tobacco can lead to the development of lung cancer, many people question whether marijuana (commonly referred to as “pot” or “weed”) can also cause lung cancer. Researchers are still working to answer this question—while some studies have found that heavy, regular marijuana use could increase a person’s risk of developing respiratory cancers, others have not identified a connection between marijuana use and an increased risk of lung cancer.

It’s important to note that aside from a possible connection to lung cancer, smoking marijuana poses many other health concerns. For example, studies have suggested that smoking marijuana can lead to inflammation of the large airways, increased airway resistance, lung hyperinflation (which occurs when air becomes trapped within the lungs), greater vulnerability to respiratory infections and various other issues.

Does vaping cause lung cancer?

Many people also wonder whether vaping can cause lung cancer. Given the relatively recent popularization of e-cigarettes, no one yet knows what long-term effects they may cause, and researchers are still working to determine whether vaping can increase a person’s risk of developing lung cancer. With that being said, many e-cigarettes contain dangerous chemicals that have previously been associated with a higher risk of lung cancer, including formaldehyde.


Asbestos—a group of minerals forming long, thin fibers—was long used in various commercial and industrial applications because of its resistance to heat, fire and chemical damage. Unfortunately, exposure to asbestos has been shown to cause lung cancer and various other malignancies, including mesothelioma, laryngeal cancer and ovarian cancer. The U.S. Department of Health and Human Services (HHS), the U.S. Environmental Protection Agency (EPA) and the International Agency for Research on Cancer (IARC) have all classified asbestos as a known human carcinogen.


Radon is a radioactive gas that’s naturally released into the air when radium, thorium and uranium break down within soil and rocks. As radon decays, it gives off small radioactive particles, which can damage the cells lining the lungs when inhaled. Although radon is present in almost all air, it usually occurs at low levels outdoors and in well-ventilated areas, and thus doesn’t typically pose a significant risk. However, individuals who inhale higher-than-normal levels of radon have an increased risk of developing lung cancer.


Crystalline silica is a mineral that’s naturally found in sand, soil and stones, as well as in man-made materials such as bricks, concrete and mortar. The most common type of crystalline silica is quartz. When airborne silica (for example, quartz dust) is inhaled, it can penetrate deep into the lungs and lead to the development of lung cancer. Although quartz dust is most commonly inhaled in industrial settings, the general population may still be exposed to it when using commercial products containing quartz, including certain cosmetics, cleansers and art materials.

Diesel exhaust

Diesel—a type of fuel made from crude oil—is commonly used in large engines, such as those in ships, trains, trucks, buses, construction vehicles, farm equipment and generators. Many studies suggest that heavy, long-term exposure to diesel exhaust can lead to the development of lung cancer. Although many people inhale relatively small amounts of diesel exhaust when driving on highways, the individuals who are most at risk include those who are exposed to it on a daily basis at work.

Moffitt’s approach to lung cancer diagnosis and treatment

It’s important to note that not everyone who smokes or comes into contact with one of the carcinogens above will develop lung cancer. There’s still much to be learned about the way the condition develops, and at Moffitt Cancer Center, we’re proud to be leading the way in lung cancer research. We not only conduct a wide range of clinical trials and lab studies, but also use our findings to shape the way in which we treat our patients. For these efforts, we’ve been named a Lung Cancer Center of Excellence by the National Cancer Institute.

If you’d like to learn more about the causes of lung cancer or would like to schedule an appointment with a member of our lung cancer team, call 1-888-663-3488, or request an appointment. No referral is required. We’ve made it our goal to provide new patients with a remarkably fast turnaround time, so you can expect to be connected with a cancer expert as soon as possible.


American Cancer Society: Diesel Exhaust and Cancer Risk
American Cancer Society: What Do We Know About E-cigarettes?
Lung Cancer Center: Does Vaping Cause Lung Cancer?
National Cancer Institute: Asbestos Exposure and Cancer Risk
National Cancer Institute: Crystalline Silica
National Cancer Institute: Radon and Cancer
National Institute on Drug Abuse: What Are Marijuana’s Effects on Lung Health?