The short answer
Formaldehyde is a strong-smelling gas used in building products and resins. High or long exposure is linked to myeloid leukemia and, less consistently, to a rare cancer of the upper throat. Pressed-wood products and poor ventilation raise indoor levels. Ventilation and low-emission products help.
Formaldehyde is classified as a known human carcinogen by IARC and the National Toxicology Program.
People are mainly exposed by breathing the gas released indoors by pressed-wood products, or at certain jobs.
It is most strongly linked to myeloid leukemia. A link to nasopharyngeal cancer has been reported, but findings are inconsistent.
A carcinogen classification describes hazard — whether something can cause cancer — not your personal risk at a given exposure.
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Worried about fumes from new furniture, or about formaldehyde at work? This page explains what the chemical is, where it shows up, and what is known about its link to cancer.
The simple version
Formaldehyde is a colorless gas with a sharp smell. It is used to make many household products and building materials. Breathing in higher amounts over time is linked to certain cancers. The link is clearest in people with heavy workplace exposure.
What formaldehyde is
Formaldehyde is a widely used industrial chemical. It turns up in pressed-wood products such as plywood and particleboard. Industrial workers, lab technicians, and mortuary workers can have higher exposure.
How people are exposed
Everyday and workplace sources include:
- Breathing gas released from new pressed-wood furniture, cabinets, and flooring.
- Working in industry, in a lab, or in a mortuary.
- Cigarette smoke and some fuel-burning appliances.
The cancer connection
NCI says formaldehyde is most strongly linked to myeloid leukemia. It has also been linked to cancer of the nasopharynx, the upper part of the throat behind the nose, but findings there are inconsistent. One large NCI study of more than 25,000 workers showed a higher risk of death from leukemia, especially myeloid leukemia, among workers exposed to formaldehyde.
NCI says the International Agency for Research on Cancer (IARC) and the National Toxicology Program, a US federal program, classify formaldehyde as a known human carcinogen.
Hazard is not the same as risk
A known-carcinogen listing is a statement about hazard. It says formaldehyde can cause cancer under some conditions. It does not say what your own risk is. That depends on how much you breathe in, for how long, and on other things about you. An embalmer who works with it daily and a person with a new bookcase share the same hazard and face very different risks.
How to lower your exposure
- Ventilate well, especially around new furniture, cabinets, or flooring.
- Choose exterior-grade pressed-wood products. EPA says they give off less. Since March 2019, composite wood products sold in the US must be labeled TSCA Title VI compliant.
- EPA also recommends moderate temperature and controlled humidity indoors.
- Cigarette smoke is a source of formaldehyde, so avoid smoking indoors.
No single chemical decides your cancer risk. For the wider picture, see our overview of cancer prevention and our page on what raises cancer risk.
The bottom line
Formaldehyde is a known human carcinogen. The useful response is practical. Find out where it gets into your air, and cut that down where you can. A carcinogen label is not a reason to lie awake.
Sources
Common questions
Does formaldehyde cause cancer?
Yes. Formaldehyde is classified as a known human carcinogen, which means there is strong evidence it can cause cancer in people. How much any one person's risk rises depends on how much they are exposed to and for how long.
How are people exposed to formaldehyde?
Most exposure happens by breathing the gas released indoors by pressed-wood products, or at certain jobs.
Which cancers are linked to formaldehyde?
NCI says the strongest link is with myeloid leukemia. A link to nasopharyngeal cancer has also been reported, but findings are inconsistent.
How can I reduce my exposure to formaldehyde?
The main steps are ventilating your home and choosing low-emission wood products.
Does a carcinogen label mean I will get cancer?
No. A classification is about hazard — whether formaldehyde can cause cancer under some conditions — not a prediction that any one exposed person will develop cancer. Your actual risk depends on the amount and length of exposure and other factors.
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Last updated: 2026-10-16Next planned review: 2028-07-05
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Cancer Explained does not originate medical claims. Every page restates guidance already published by the National Cancer Institute, the CDC, the USPSTF and the FDA, in plain language, with the source cited so you can check the original yourself. AI does the translating and organizing; automated checks test claims, citations, clarity and safety before anything publishes, and this is translation and navigation, not clinical judgment. Nothing here is personal medical advice, and no page can account for your particular situation.
Editorial status: Source checked — This page was written with AI assistance and then compared with the sources listed on it, looking for statements those sources do not back up. That check is not a sentence-by-sentence record and can miss errors. It is not a medical review, and it does not confirm the page is complete or right for your situation.
Human medical review: not completed. Pages here are not signed off by a clinician before they publish. That is not an oversight we are quietly working around: we restate published guidance and cite it, so the authority belongs to the source rather than to us, and every page names where its claims come from — you can verify us instead of trusting us. Where a volunteer clinician has reviewed a page, their name and credentials appear on it; where no name appears, no clinician has checked it. We are glad to have reviewers and are recruiting them, and we do not hold pages back waiting for one. Use this site to understand your situation and to ask better questions of the people treating you.
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