The Scary Facts About Formaldehyde in Cigarette Smoke

cigarette smoke and lit cigarette
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Formaldehyde is a colorless, flammable gas with a strong odor. A small amount of formaldehyde is produced in our bodies naturally, but most formaldehyde is released into the environment by the burning of fuels and household waste. Cigarette smoke and e-cigarette vapor both contain formaldehyde.

Most of us think of formaldehyde as a liquid but, in reality, we are probably thinking of the substance used to preserve biological specimens --- formalin --- a mixture of formaldehyde gas, water, and methyl alcohol.

Formaldehyde is also an industrial chemical that is present in a wide variety of applications. It's used to produce building materials (including pressed wood products), many household products, and is even a part of the manufacturing process for wrinkle-free cloth. Formaldehyde is also used in glues, adhesives, and disinfectant products.

Surprisingly, formaldehyde is also used to deactivate live viruses and toxins used in making vaccines. The process is regulated by the U.S. Food and Drug Administration.

Most Common Human Exposures

The most common way people are exposed to formaldehyde is by breathing air that is tainted with it in poorly ventilated indoor environments. Products made with formaldehyde can release this gas over time, causing the concentration to build up in enclosed areas.

A common source of formaldehyde exposure comes from cigarette smoke, which is laden with formaldehyde.

Research suggests that e-cigarette vapor also contains formaldehyde, though in quantities that are usually less than what is present in cigarette smoke. Breathing secondhand and third-hand smoke indoors is a contributing factor for formaldehyde exposure as well.

In Cigarette Smoke,

Formaldehyde is a by-product of the combustion process of cigarette smoking. Formaldehyde is generated by additives, specifically sugars, burnt with the cigarette. In general, it is the very the first puff of the cigarette (first-hand smoke) that kicks off abnormally high levels of formaldehyde, and it is inhaled to a lesser degree by people by people in the vicinity of the cigarette smoker (second-hand smoke).

Even more interestingly, recently re-discovered and newly published research from the early Nineteen Nineties conducted under rigorously controlled conditions by the Phillip Morris Tobacco Company established that the chemicals from every cigarette smoked remain in the environment --- on the walls, the carpeting, the furnishings --- for months after smoking, circulate repeatedly in the air, and even inter-react to form new toxins and carcinogens. Elevated levels of toxic smoking chemicals, including formaldehyde, remain in the air for more than 12 hours after smoking.

Formaldehyde is responsible for some of the nose, throat and eye irritation smokers experience when breathing in cigarette smoke.

In E-Cigarette Vapor

In a letter published in the January 22, 2015 issue New England Journal of Medicine, researchers suggest that a "masked" form of formaldehyde is present in the condensed liquid from e-cigarette vapor in concentrations much higher than in cigarette smoke. The scientists call it masked because it is a slightly different form of formaldehyde—one that they feel is more likely to be deposited on delicate lung tissue, once inhaled.

Formaldehyde levels in the blood deriving from e-cigarette vapor tend to register less than the same blood levels of formaldehyde tracing to cigarette smoke. The average measured blood level of formaldehyde deriving from e-cigarette vapor is approximately 1mg, but this value is dependent in part on the heat setting of the electronic cigarette device being used to administer the e-cigarette vapor and the amount inhaled.

Short-Term Health Risks

When formaldehyde is present in the air at levels exceeding 0.1 parts per million, some individuals may experience short-term health effects, including:

  • Watering of the eyes
  • Burning sensations of the eyes, nose, and throat
  • Coughing
  • Wheezing
  • Nausea
  • Skin irritation

Some people are quite sensitive to formaldehyde, while others have no reaction to the same level of exposure. People who are sensitive to formaldehyde run the risk of developing asthma from continued exposure to inhaled formaldehyde.

Long-Term Health Risks

Lab studies have shown that exposure to formaldehyde could cause nasal cancer in rats, and some studies of industrial workers have suggested that formaldehyde exposure might be associated with nasal cancer and nasopharyngeal cancer in humans.

In 1995, the International Agency for Research on Cancer (IARC) concluded that formaldehyde was a probable human carcinogen. In a reevaluation of existing data in June 2004, the IARC reclassified formaldehyde as a known human carcinogen.

Because formaldehyde rapidly changes in chemical composition once it's absorbed, scientists think inhaled formaldehyde is primarily an upper respiratory tract cancer risk. More research is needed to understand what happens when formaldehyde reaches the lungs.

Researchers also believe that formaldehyde is a significant risk factor for myeloid leukemia.

To date, science has identified more than 7,000 chemicals, including 250 poisonous and 70 carcinogenic compounds in commercially produced cigarette smoke.

If you're still smoking, start working on a plan to quit. Smoking is a dangerous habit that has serious health consequences.

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7 Sources
Verywell Mind uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
  1. American Chemistry Council. Why is Formaldehyde Used to Make Vaccines? Washington, DC: American Chemistry Council 2020

  2. National Cancer Institute. Formaldehyde and Cancer Risk. Reviewed June 10, 2011. Washington, DC: US Department of Health and Human Services, National Cancer Institute at the National Institutes of Health 2020

  3. Baker RR. The generation of formaldehyde in cigarettes--Overview and recent experiments. Food Chem Toxicol. 2006;44(11):1799-1822. doi:10.1016/j.fct.2006.05.017

  4. Whitlatch A. Schick S. Thirdhand Smoke at Philip MorrisNicotine and Tobacco Research. December 2019;21(12):1680–1688. doi:10.1093/ntr/nty153

  5. New England Journal of Medicine (Letter to the Editor). Hidden Formaldehyde in E-Cigarette Aerosols. N Engl J Med. 2015;372:392-394. doi:10.1056/NEJMc1413069

  6. Gillmana IG, Kistler KS, Stewart EW, Paolantonioa AR. Effect of variable power levels on the yield of total aerosol mass and formation of aldehydes in e-cigarette aerosols. Regulatory Toxicology and Pharmacology. March 2016;75:58-65. doi:10.1016/j.yrtph.2015.12.019

  7. World Health Organization International Agency for Research on Cancer. IARC Monographs on the Evaluation of Carcinogenic Risks to Humans. Vol. 88. Formaldehyde, 2-Butoxyethanol and 1-tert-Butoxypropan-2-ol. 2-9 June 2004. Lyon, France: World Health Organization International Agency for Research on Cancer 2006