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Tobacco Prevention & Control

Elimination Of Exposure To Secondhand Smoke (SHS):
The Science Behind Secondhand Smoke

Secondhand smoke contains over 4,000 and up to 8,000 toxic chemicals: about 60 are known carcinogens and can cause cancer. The  2006 U.S. Surgeon General’s report said “there is no risk-free level of exposure to secondhand smoke.”  The report further found that non-smoking sections and high-tech ventilation systems are ineffective for protecting people against the toxins found in secondhand smoke.

Secondhand smoke is a direct cause of heart disease and lung cancer; and it is a trigger for asthma, allergies, and other respiratory ailments in people who don’t smoke.

Secondhand smoke is the combination of two forms of smoke from burning tobacco products:

  • Sidestream smoke, or smoke that is emitted between the puffs of a burning cigarette, pipe, or cigar, and
  • Mainstream smoke, or the smoke that is exhaled by the smoker.

The federal Environmental Protection Agency (EPA) documented that secondhand smoke causes lung cancer in adult nonsmokers and impairs the respiratory health of children. The National Academy of Sciences, the U.S. Surgeon General, the National Cancer Institute, and the U.S. Centers for Disease Control and Prevention support these findings.

The EPA also classified secondhand smoke as a Group A carcinogen, which means there is sufficient evidence that the substance causes cancer in humans. The Group A designation has been used by the EPA for only 15 other pollutants, including asbestos, radon, and benzene. Nonsmokers absorb nicotine and other compounds just as smokers do, and the greater exposure to secondhand smoke, the greater the level of these harmful compounds in the body.

Short-Term Effects of Secondhand Smoke

In the few minutes it takes to eat a restaurant meal or take a car ride, exposure to secondhand tobacco smoke may cause nonsmokers to experience headaches and nausea, burning eyes, sinus irritation and impaired concentration.

According to the California EPA, Office of Environmental Health Hazard Assessment, regular exposure to secondhand smoke can lead to:

Cardiovascular Problems

  • Damage to cell walls in the circulatory system
  • Thickening of the blood and arteries as blood platelets begin sticking together
  • Hardening of the arteries or heart disease, increasing the chance of heart attack or stroke

Respiratory Problems

  • Increased susceptibility to and aggravation of colds, flu and other viruses
  • Increased susceptibility to pneumonia and bronchitis
  • Increased frequency of asthma attacks
  • Aggravation of allergies

Immune System Problems

  • Increased middle ear infections in children
  • HIV-positive people may develop full blown AIDS four times as quickly

Developmental Problems

  • Exposure to secondhand smoke increases the risk of Sudden Infant Death Syndrome (SIDS) in babies by a factor of four
  • Increased likelihood of low birth weight


  • Cell mutations caused by the mutagens and carcinogens in tobacco smoke
  • Increases a nonsmoker’s risk of pre-cancerous lesions in the lung
  • Increased likelihood of lung cancer—up to 3,000 deaths from lung cancer each year in the U.S. are attributed to secondhand smoke.

Smoke Free Dining is Just Good Taste

Click here to find out about smoke free restaurants in South Carolina.