Formaldehyde is a strong-smelling, colorless gas used in making building materials and many household products. When dissolved in water it is called formalin, which is commonly used as an industrial disinfectant, and as a preservative in funeral homes and medical labs. Formaldehyde also occurs naturally in the environment
How are people exposed to formaldehyde?
The main exposure is by inhaling formaldehyde
- Formaldehyde is normally present at low levels (less than 0.03 parts per million) in both indoor and outdoor air.
- Most inhaled formaldehyde is broken down by the cells lining the mouth, nose, throat, and airways, so that less than a third is absorbed into the blood. The liquid form can be absorbed through the skin.
In the workplace
The US Occupational Safety and Health Administration (OSHA) has established limits for the amount of formaldehyde that workers can be exposed to at their place of work
- At present, the limit is at 0.75 ppm
- Employers must monitor formaldehyde levels and provide respirators and protective clothing as needed to limit exposure
Can formaldehyde cause cancer?
Exposure to high levels of formaldehyde in medical and occupational settings has been linked to some types of cancer in humans, but the effect of exposure to small amounts is less clear
Does formaldehyde cause any other health problems?
When formaldehyde is present in the air at levels higher than 0.1 parts per million (ppm), some people may have health effects, such as: watery eyes, burning sensations of the eyes, nose, and throat, coughing wheezing, skin irritation, and an itchy, red rash.
Studies in the lab
In rats, inhaled formaldehyde was linked to cancers of the nasal cavity and leukemia in addition to stomach tumors and no increase in any kind of tumor or cancer in another group of rats given the same amount of water containing formaldehyde.
In the home:
Use “exterior-grade” pressed-wood products to limit formaldehyde exposure in the home. These products give off less formaldehyde because they contain phenol resins, not urea resins.
- Formaldehyde levels in homes can also be reduced by not allowing smoking inside and by ensuring adequate ventilation (use your stove vent fan for example).
Studies in people
In one study, inhaling formaldehyde at levels at a concentration of 1.9 parts per million (ppm) for 40 minutes did not increase blood levels of formaldehyde
- Several epidemiology studies of people exposed to formaldehyde in the workplace have reported a link between formaldehyde exposure and cancer of the nasopharynx (the uppermost part of the throat), but this outcome has not been observed in other studies
What Expert Agencies Say
Several agencies (national and international) study different substances in the environment to determine if they can cause cancer.
- The National Toxicology Program (NTP) is formed from parts of several different US government agencies, including the National Institutes of Health (NIH), the Centers for Disease Control and Prevention (CDC), and the Food and Drug Administration (FDA). The NTP lists formaldehyde as “known to be a human carcinogen.”
- International Agency for Research on Cancer (IARC) is part of the World Health Organization (WHO). Its major goal is to identify causes of cancer. IARC has concluded that formaldehyde is “carcinogenic to humans” based on higher risks of nasopharyngeal cancer and leukemia.
