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Lung Cancer and the Environment

Lung cancer is the leading cause of cancer deaths in the United States. Lung cancer forms in the tissue of the lung, usually in the cells lining the air passages. Cigarette smoking is the single most crucial risk factor for, and leading cause of, lung cancer. Exposure to radon is the second leading cause of lung cancer.

The International Agency for Research on Cancer (IARC) has identified the following substances as lung cancer-causing agents:

  • Arsenic
  • Asbestos
  • Bischloromethlyl ether
  • Chromium
  • Nickel
  • Polycyclic aromatic compounds
  • Radon
  • Vinyl chloride.

A history of certain lung diseases also increases the risk for lung cancer. Diets low in fruits and vegetables might increase the risk of lung cancer in persons who smoke.

Environmental tobacco smoke (also called secondhand smoke) is a well-established cause of lung cancer. Air pollution and diesel exhaust have also been shown to have a slight increase in lung cancer morbidity and/or mortality. However, the impact of outdoor air pollution on lung cancer needs further study.

Exposure and Risk

Cigarette smoking is the most common cause of lung cancer. It remains the leading preventable cause of death in the United States. Even for nonsmokers, exposure to environmental tobacco smoke increases the risk for lung cancer. The 2006 Surgeon General's Report says the evidence suggests that secondhand smoke exposure can cause lung cancer in lifetime nonsmokers, regardless of where the exposure occurs (e.g., home, work, restaurants). Every year, about 3,000 nonsmokers in the United States die from lung cancer caused by secondhand smoke. There is no risk-free level of secondhand smoke exposure.

Studies also indicate that exposure to certain chemicals may increase the risk for lung cancer, especially among smokers. These chemicals include:

  • arsenic,
  • chromium,
  • silica,
  • substances used or produced in foundries, and
  • substances produced by processing coal.

Radon exposure is the second leading cause of lung cancer after tobacco smoke. Radon is a naturally occurring, colorless, odorless, tasteless, radioactive gas that can be found throughout the United States. It can infiltrate homes, offices, and schools and cause high indoor radon levels. The greatest exposure likely occurs in homes where most personal time is spent.

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Not smoking is the most effective way to reduce the risk for lung cancer. Limiting exposure to environmental tobacco smoke and testing homes for radon also reduce the risk for lung cancer. Eating fresh fruits and vegetables may also decrease risk, as well as help prevent other diseases. Also, workers in high risk jobs should follow appropriate health and safety rules, like wearing protective equipment.

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Additional Information

Radon Task Force, Environmental Public Health Tracking Program

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