Skip to main content
An official website of the United States government


Formaldehyde is commonly used as a preservative.

What is formaldehyde?

Formaldehyde is a colorless, strong-smelling, flammable chemical that is produced industrially and used in building materials such as particleboard, plywood, and other pressed-wood products. In addition, it is commonly used as a fungicide, germicide, and disinfectant, and as a preservative in mortuaries and medical laboratories. Formaldehyde also occurs naturally in the environment. It is produced during the decay of plant material in the soil and during normal chemical processes in most living organisms. It is also a combustion product found in tobacco smoke.

How are people exposed to formaldehyde?

People are exposed primarily by inhaling formaldehyde gas or vapor from the air or by absorbing liquids containing formaldehyde through the skin. Workers who produce formaldehyde or products that contain formaldehyde—as well as laboratory technicians, certain health care professionals, and mortuary employees—may be exposed to higher levels of formaldehyde than people in the general population.

The general public may be exposed to formaldehyde by breathing contaminated air from sources such as pressed-wood products, tobacco smoke, and automobile tailpipe emissions. Another potential source of exposure to formaldehyde is the use of unvented fuel-burning appliances, such as gas stoves, wood-burning stoves, and kerosene heaters.

Which cancers are associated with exposure to formaldehyde?

Studies of workers exposed to high levels of formaldehyde, such as industrial workers and embalmers, have found that formaldehyde causes myeloid leukemia and rare cancers, including cancers of the paranasal sinuses, nasal cavity, and nasopharynx.

How can exposures be reduced?

The U.S. Environmental Protection Agency recommends the use of “exterior-grade” pressed-wood products to limit formaldehyde exposure in the home. Formaldehyde levels in homes and work settings can also be reduced by ensuring adequate ventilation, moderate temperatures, and reduced humidity levels through the use of air conditioners and dehumidifiers.

Selected References:

  • National Institute of Occupational Safety and Health. Formaldehyde, Workplace Safety and Health Topics. Atlanta, GA: Centers for Disease Control and Prevention. Available online. Last accessed February 14, 2019.
  • National Toxicology Program. Formaldehyde, Report on Carcinogens, Fifteenth Edition. Triangle Park, NC: National Institute of Environmental Health and Safety, 2021. Also available online. Last accessed December 5, 2022.
  • U.S. Environmental Protection Agency. Formaldehyde. Washington, DC: U.S. Environmental Protection Agency, 2013. Available online. Last accessed February 14, 2019.
  • Updated:

If you would like to reproduce some or all of this content, see Reuse of NCI Information for guidance about copyright and permissions. In the case of permitted digital reproduction, please credit the National Cancer Institute as the source and link to the original NCI product using the original product's title; e.g., “Formaldehyde was originally published by the National Cancer Institute.”