Formaldehyde and Cancer: Questions and Answers 

Key Points

• Formaldehyde is a colorless, flammable, strong-smelling gas that is used 

to manufacture building materials and produce many household products 

(see Question 1). 

• Formaldehyde sources in the home include pressed wood products, 

cigarette smoke, and fuel-burning appliances (see Question 2). 

• When exposed to formaldehyde, some individuals may experience 

various short-term health effects (see Question 3). 

• Formaldehyde has been classified as a human carcinogen (cancer-causing 

substance) by the International Agency for Research on Cancer and as a 

probable human carcinogen by the U.S. Environmental Protection 

Agency (see Question 4). 

• Research studies of workers exposed to formaldehyde have suggested an 

association between formaldehyde exposure and cancers of the nasal 

sinuses, nasopharynx, and brain, and possibly leukemia (see Question 5). 

1. What is formaldehyde? 

Formaldehyde is a colorless, flammable, strong-smelling gas. It is an important industrial 

chemical used to manufacture building materials and to produce many household 

products. It is used in pressed wood products such as particleboard, plywood, and 

fiberboard, glues and adhesives, permanent press fabrics, paper product coatings, and 

certain insulation materials. In addition, formaldehyde is commonly used as an industrial 

fungicide, germicide, and disinfectant, and as a preservative in mortuaries and medical 

laboratories.

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2. How is the general population exposed to formaldehyde?

According to a 1997 report by the U.S. Consumer Product Safety Commission, 

formaldehyde is normally present in both indoor and outdoor air at low levels, usually 

less than 0.03 parts of formaldehyde per million parts of air (ppm). Materials containing 

formaldehyde can release formaldehyde gas or vapor into the air. Formaldehyde can also 

be released by burning wood, kerosene, natural gas, or cigarettes; through automobile 

emissions; or from natural processes. 

During the 1970s, urea-formaldehyde foam insulation (UFFI) was used in many homes. 

However, few homes are now insulated with UFFI. Homes in which UFFI was installed 

many years ago are not likely to have high formaldehyde levels now. Pressed wood 

products containing formaldehyde resins are often a significant source of formaldehyde 

in homes. Other potential indoor sources of formaldehyde include cigarette smoke and 

the use of unvented, fuel-burning appliances such as gas stoves, wood-burning stoves, 

and kerosene heaters. 

Industrial workers who produce formaldehyde or formaldehyde-containing products, 

laboratory technicians, health care professionals, and mortuary employees may be 

exposed to higher levels of formaldehyde than the general public. Exposure occurs 

primarily by inhaling formaldehyde gas or vapor from the air or by absorbing liquids 

containing formaldehyde through the skin. 

3. What are the short-term health effects of formaldehyde exposure? 

When formaldehyde is present in the air at levels exceeding 0.1 ppm, some individuals 

may experience health effects such as watery eyes; burning sensations of the eyes, nose, 

and throat; coughing; wheezing; nausea; and skin irritation. Some people are very 

sensitive to formaldehyde, while others have no reaction to the same level of exposure. 

4. Can formaldehyde cause cancer? 

Although the short-term health effects of formaldehyde exposure are well known, less is 

known about its potential long-term health effects. In 1980, laboratory studies showed 

that exposure to formaldehyde could cause nasal cancer in rats. This finding raised the 

question of whether formaldehyde exposure could also cause cancer in humans. In 1987, 

the U.S. Environmental Protection Agency (EPA) classified formaldehyde as a probable 

human carcinogen under conditions of unusually high or prolonged exposure (1). Since 

that time, some studies of industrial workers have suggested that formaldehyde exposure 

is associated with nasal cancer and nasopharyngeal cancer, and possibly with leukemia. 

In 1995, the International Agency for Research on Cancer (IARC) concluded that 

formaldehyde is a probable human carcinogen. However, in a reevaluation of existing 

data in June 2004, the IARC reclassified formaldehyde as a known human 

carcinogen (2). 
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5. What have scientists learned about the relationship between formaldehyde and 

cancer? 

Since 1980, the National Cancer Institute (NCI) has conducted studies to determine 

whether there is an association between occupational exposure to formaldehyde and an 

increase in the risk of cancer. The results of this research have provided the EPA and the 

Occupational Safety and Health Administration (OSHA) with information to evaluate the 

potential health effects of workplace exposure to formaldehyde. 

Long-term effects of formaldehyde have been evaluated in epidemiological studies 

(studies that attempt to uncover the patterns and causes of disease in groups of people). 

One type of study, called a cohort study, looks at populations that have different 

exposures to a particular factor, such as formaldehyde. A cohort is a group of people 

who are followed over time to see whether a disease develops. Another kind of study, a 

case-control study, begins with people diagnosed as having a disease (cases) and 

compares them to people without the disease (controls). 

Several NCI studies have found that anatomists and embalmers, professions with 

potential exposure to formaldehyde, are at an increased risk for leukemia and brain 

cancer compared with the general population. In 2003, a number of cohort studies were 

completed among workers exposed to formaldehyde. One study, conducted by the NCI, 

analyzed 25,619 workers in formaldehyde industries and estimated each worker’s 

exposure to formaldehyde while at work (3). The analysis found an increased risk of 

death due to leukemia, particularly myeloid leukemia, among the workers exposed to 

formaldehyde. This risk was associated with increasing peak and average levels of 

exposure and the duration of exposure, but not cumulative exposure. Another study of 

14,014 textile workers performed by the National Institute for Occupational Safety and 

Health (NIOSH) also found an association between the duration of exposure to 

formaldehyde and leukemia deaths. However, an additional cohort study of 11,039 

British industry workers found no association between cumulative formaldehyde 

exposure and leukemia deaths. 

Formaldehyde undergoes rapid chemical changes immediately after absorption. 

Therefore, some scientists think effects of formaldehyde at sites other than the upper 

respiratory tract are unlikely. However, some laboratory studies suggest that 

formaldehyde may affect the lymphatic and blood systems. Based on both the 

epidemiologic data from cohort studies and the experimental data from laboratory 

research, NCI investigators have concluded that exposure to formaldehyde may cause 

leukemia, particularly myeloid leukemia, in humans. However, inconsistent results from 

other studies suggest that further research is needed before definite conclusions are 

drawn. 

Several case-control studies and cohort studies, including analysis of the large NCI 

cohort, have reported an association between formaldehyde exposure and nasopharyngeal 

cancer, although others have not. Data from extended follow-up of the NCI study found 

that the excess of nasopharyngeal cancer observed in the earlier report persisted (4). 
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Earlier analysis of the NCI cohort found increased lung cancer deaths among industrial 

workers compared with the general U.S. population. However, the rate of lung cancer 

deaths did not increase with higher levels of formaldehyde exposure. This observation 

led the researchers to conclude that factors other than formaldehyde exposure might have 

caused the increased deaths. New data on lung cancer from the extended follow-up did 

not find any relationship between formaldehyde exposure and lung cancer mortality. 

6. What has been done to protect workers from formaldehyde? 

In 1987, OSHA passed a law that reduced the amount of formaldehyde to which workers 

can be exposed over an 8-hour work day from 3 ppm to 1 ppm. In May 1992, the law 

was amended, and the formaldehyde exposure limit was further reduced to 0.75 ppm. 

7. How can people limit formaldehyde exposure in their homes? 

The EPA recommends the use of “exterior-grade” pressed wood products to limit 

formaldehyde exposure in the home. Before purchasing pressed wood products, 

including building materials, cabinetry, and furniture, buyers should ask about the 

formaldehyde content of these products. Formaldehyde levels in homes can also be 

reduced by ensuring adequate ventilation, moderate temperatures, and reduced humidity 

levels through the use of air conditioners and dehumidifiers. 

8. Where can people find more information about formaldehyde? 

The following organizations can provide additional resources that readers may find 

helpful: 

The U.S. Consumer Product Safety Commission (CPSC) has information about 

household products that contain formaldehyde. The CPSC can be contacted at: 

 

Address: U.S. Consumer Product Safety Commission 

4330 East-West Highway 

Bethesda, MD 20814–4408 

Telephone: 1–800–638–CPSC (1–800–638–2772) 

TTY: 1–800–638–8270 

E-mail: info@cpsc.gov 

Web site: http://www.cpsc.gov 

The U.S. Food and Drug Administration (FDA) maintains information about cosmetics 

and drugs that contain formaldehyde. The FDA can be contacted at: 

Address: U.S. Food and Drug Administration 

 5600 Fishers Lane 

Rockville, MD 20857–0001 

Telephone: 1–888–INFO–FDA (1–888–463–6332) 

Web site: http://www.fda.gov 
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The Occupational Safety and Health Administration (OSHA) has information about 

occupational exposure limits for formaldehyde. OSHA can be contacted at: 

Address: U.S. Department of Labor 

Occupational Safety and Health Administration 

 200 Constitution Avenue 

 Washington, DC 20210 

Telephone: 1–800–321–OSHA (1–800–321–6742)

Web site: http://www.osha.gov 

Selected References 

1. U.S. Environmental Protection Agency, Office of Air and Radiation. Report to Congress 

on Indoor Air Quality, Volume II: Assessment and Control of Indoor Air Pollution, 1989. 

2. International Agency for Research on Cancer (June 2004). IARC Classifies 

Formaldehyde as Carcinogenic to Humans. Retrieved June 30, 2004, from: 

http://www.iarc.fr/ENG/Press_Releases/archives/pr153a.html. 

3. Hauptmann M, Lubin JH, Stewart PA, Hayes RB, Blair A. Mortality from 

lymphohematopoietic malignancies among workers in formaldehyde industries. Journal 

of the National Cancer Institute 2003; 95(21): 1615–1623. 

4. Hauptmann M, Lubin JH, Stewart PA, Hayes RB, Blair A. Mortality from solid cancers 

among workers in formaldehyde industries. American Journal of Epidemiology 2004; 

159(12): 1117–1130. 

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Related Resources

Publications (available at http://www.cancer.gov/publications) 

• Cancer and the Environment: What You Need To Know, What You Can Do

• What You Need To Know AboutTM Cancer

National Cancer Institute (NCI) Resources

Cancer Information Service (toll-free)

 Telephone: 1–800–4–CANCER (1–800–422–6237) 

 TTY: 1–800–332–8615 
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Online 

NCI’s Web site: http://www.cancer.gov 

LiveHelp, NCI’s live online assistance: 

https://cissecure.nci.nih.gov/livehelp/welcome.asp

This fact sheet was reviewed on 7/30/04