Carcinogens in Tobacco Products

Tobacco smoke

Cigarettes, cigars, and pipe tobacco are made from dried tobacco leaves. Other substances are added for flavor and to make smoking more pleasant. The smoke from these products is a complex mixture of chemicals produced by the burning of tobacco and its additives.

Tobacco smoke is made up of more than 7,000 chemicals, including over 70 known to cause cancer (carcinogens). Some of the chemicals found in tobacco smoke include:

  • Nicotine (the addictive drug that produces the effect people are looking for and one of the harshest chemicals in tobacco smoke)
  • Cyanide
  • Benzene
  • Formaldehyde
  • Methanol (wood alcohol)
  • Acetylene (the fuel used in welding torches)
  • Ammonia
  • The poison gases carbon monoxide and nitrogen oxide
  • Vinyl chloride
  • Ethylene oxide
  • Arsenic
  • Chromium
  • Cadmium
  • Nitrosamines
  • Polynuclear aromatic hydrocarbons

Many of these substances cause cancer. Some cause heart and lung diseases, too. All of these products can be deadly.

Radioactive materials in tobacco smoke

Radioactive materials are in the tobacco leaves used to make cigarettes and cigars; the amount depends on the soil the plants were grown in and fertilizers used. But this means that the smoke from burning these leaves has small amounts of radioactive material, too, which smokers take into their lungs as they inhale. These radioactive particles build up in the lungs, and over time can mean a big dose of radiation. This may be another key factor in smokers getting lung cancer.

How is cigar smoke different?

Cigar smoke has higher concentrations of some toxic and carcinogenic compounds than cigarette smoke.

Because of the aging process used to make cigars, cigar tobacco has a high concentration of nitrogen compounds (nitrates and nitrites).

When the fermented cigar tobacco is smoked, these compounds give off several tobacco-specific nitrosamines (TSNAs), some of the most potent cancer-causing substances known.

Also, because the cigar wrapper is less porous, the tobacco doesn’t burn as completely. The result is a higher concentration of nitrogen oxides, ammonia, carbon monoxide, and tar – all very harmful substances.

Smokeless tobacco products

The snuff and chewing tobacco products most widely used in the United States have very high levels of tobacco-specific nitrosamines (TSNAs). There are other cancer-causing agents in smokeless tobacco, too, such as benzo[a]pyrene and other polycyclic aromatic carcinogens. These carcinogens are absorbed through the mouth and may be why several types of cancer are linked to use of smokeless tobacco.

Swedish snus has fewer TSNAs that are known to cause cancer. But there are other carcinogens in snus besides TSNAs.

Which is riskier? Smokeless tobacco or cigarette smoking?

Smokeless tobacco products are less lethal than cigarettes. On average, they kill fewer people than cigarettes. But smokeless tobacco hurts and kills people all the same. Even though they are marketed as a less harmful alternative to smoking, smokeless products can be deadly. And they have not been proven to help smokers quit.

Smokers who delay quitting by using smokeless products between cigarettes greatly increase their risk of lung cancer. They also set themselves up for new health problems caused by smokeless tobacco.

Electronic cigarettes

E-cigarettes and other electronic nicotine delivery systems (ENDS) are often used as substitutes for cigarettes or other tobacco products.

Marketers of e-cigarettes and other ENDS claim the ingredients are safe. But the aerosols these products produce contain addictive nicotine, flavorings, and a variety of chemicals, some known to be toxic or cause cancer. Because these products aren’t regulated, the amounts of nicotine and other substances in them can vary widely. Research hasn’t yet established the level of potential risk from these unregulated and non-standardized products.

The FDA has not approved ENDS as quitting aids. No company making ENDS has yet been willing to subject these products to the FDA’s rigorous testing of proposed quit-smoking devices and medicines.

The long-term health effects of these devices are being studied.

The American Cancer Society medical and editorial content team
Our team is made up of doctors and master’s-prepared nurses with deep knowledge of cancer care as well as journalists, editors, and translators with extensive experience in medical writing.

Baker F, Ainsworth SR, Dye JT, et al. Health risks associated with cigar smoking. JAMA. 2000;284(6):735-740.

Karagueuzian HS, White C, Sayre J, Norman A. Cigarette smoke radioactivity and lung cancer risk. Nicotine Tob Res. 2012;14(1):79-90.

Piano MR, Benowitz NL, Fitzgerald GA, et al. Impact of smokeless tobacco products on cardiovascular disease: implications for policy, prevention, and treatment: a policy statement from the American Heart Association. Circulation. 2010;122(15):1520-1544.

Shousha HA, Ahmad F. Natural radioactivity contents in tobacco and radiation dose induced from smoking. Radiat Prot Dosimetry. 2012;150(1):91-95.

U.S. Food and Drug Administration. Harmful and Potentially Harmful Constituents in Tobacco Products and Tobacco Smoke: Established List. March 2012. Accessed at on November 5, 2015.

US Department of Health and Human Services. The Health Consequences of Involuntary Exposure to Tobacco Smoke: A Report of the Surgeon General. 2006. Accessed at on November 5, 2015.

US Department of Health & Human Services. The Health Consequences of Smoking---50 Years of Progress: A Report of the Surgeon General. 2014. Accessed at on November 5, 2015.

US Department of Health and Human Services. Preventing Tobacco Use Among Youth and Young Adults: A Report of the Surgeon General. 2012. Accessed at on November 5, 2015.


Last Medical Review: November 12, 2015 Last Revised: November 12, 2015

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