The short answer
Asbestos is a natural fiber once used in building materials. Breathing in its fibers can cause mesothelioma and cancers of the lung, larynx and ovary, often decades later. Do not disturb material that may contain asbestos, and use trained professionals to test for and remove it.
Asbestos is classified as a known human carcinogen (IARC Group 1).
People are exposed by breathing in fibers from disturbed or damaged asbestos-containing material, most often at work.
NCI, citing IARC, says asbestos causes mesothelioma and cancers of the lung, larynx, and ovary.
A carcinogen classification describes hazard — whether something can cause cancer — not your personal risk at a given exposure.
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This page is for anyone who lives or works around older buildings and wants to understand asbestos. It explains what asbestos is, how people are exposed, and its link to cancer.
The simple version
Asbestos is a group of natural minerals made of tiny fibers. Those fibers can get into the air. If people breathe them in, they can cause cancer. NCI says symptoms can take 10 to 40 years or more to appear. OSHA says there is no safe level of asbestos exposure for any type of asbestos fiber.
What asbestos is
NCI describes asbestos as six minerals that occur naturally in the environment as bundles of fibers. They resist heat and chemicals. EPA notes that chrysotile asbestos, the only form still imported to the US, appears in products such as brake blocks and sheet gaskets. Asbestos can still be found in older buildings and equipment.
How people are exposed
Common ways people come into contact with it:
- Breathing in fibers released from asbestos-containing material that is disturbed or damaged.
- Working in shipbuilding, asbestos mining, insulation, construction, demolition, or automotive brake repair. NCI lists these among the jobs with the highest exposure.
- Living with someone who worked with asbestos. NCI says family members of heavily exposed workers face an increased risk of mesothelioma, through contaminated clothing and personal items.
The cancer connection
Asbestos is best known for causing mesothelioma. NCI, citing IARC, says asbestos also causes cancers of the lung, larynx (voice box), and ovary. NCI also says people who smoke and are exposed to asbestos have a lung cancer risk greater than the two individual risks added together.
The International Agency for Research on Cancer (IARC), part of the World Health Organization, weighs the evidence on what causes cancer. It places asbestos in Group 1, carcinogenic to humans. That is the strongest evidence category.
Hazard is not the same as risk
Two words get mixed up here: hazard and risk. Listing asbestos as a carcinogen is a statement about hazard. It means the material can cause cancer under some conditions. It says nothing about your own risk. That depends on how much you breathed in, for how long, and other things about you. Two agents in the same group can carry very different real-world risks. The label answers "can it cause cancer?" It does not answer "how likely is that for me?"
How to lower your exposure
- Do not disturb, sand, or drill material that may hold asbestos in an older home.
- If you think material contains asbestos, use trained, licensed professionals to test for it and remove it. Ask your state or local health or environmental agency who is licensed where you live.
- Follow workplace safety rules and use the protective equipment your employer provides if you work around it.
- If you smoke, ask your care team for help quitting. Smoking and asbestos together raise lung cancer risk more than the two risks added together.
Are you looking at your overall cancer risk? Small, steady steps add up. To see where asbestos sits among all the things that affect cancer risk, read our overview of cancer prevention and what raises cancer risk.
The bottom line
Asbestos is a known human carcinogen (IARC Group 1). The most useful thing you can do is learn where exposure comes from. Then take sensible steps to cut it. Do not lose sleep over a single label. Put your energy into the biggest risks you can control.
Common questions
Does asbestos cause cancer?
Yes. Asbestos 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 asbestos?
By breathing in fibers released from disturbed or damaged asbestos-containing material. NCI lists jobs with the highest exposure, such as shipbuilding, insulation work, construction, demolition and brake repair. Family members of heavily exposed workers can be exposed through clothing and personal items.
Which cancers are linked to asbestos?
NCI, citing IARC, says asbestos causes mesothelioma and cancers of the lung, larynx, and ovary.
How can I reduce my exposure to asbestos?
Do not disturb material that may contain asbestos, and use trained, licensed professionals for testing and removal. Follow workplace safety rules if you work around it.
Does a carcinogen label mean I will get cancer?
No. A classification is about hazard — whether asbestos 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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