The short answer
1,3-Butadiene is a gas used to make synthetic rubber and plastics, and is present in vehicle exhaust and tobacco smoke. Exposure is linked to leukemia. Emissions controls and avoiding smoke reduce exposure.
1,3-Butadiene is classified as a known human carcinogen (IARC Group 1).
People are mainly exposed by breathing the gas at work, or from vehicle exhaust and tobacco smoke.
It is most strongly linked to leukemia and other blood cancers.
A carcinogen classification describes hazard — whether something can cause cancer — not your personal risk at a given exposure.
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The full explanation.
The simple version
1,3-Butadiene is a gas used mainly to make synthetic rubber and plastics. It is also in car exhaust and cigarette smoke. Breathing it over time, mostly at certain jobs, is linked to leukemia.
What 1,3-butadiene is
1,3-Butadiene is a colorless gas with a gasoline-like smell. Industry uses it to make synthetic rubber products such as tires, resins, and plastics. It is also a starting point for other chemicals.
How people are exposed
Exposure happens mainly among workers who breathe contaminated air on the job.
- Work in synthetic-rubber or plastics plants, and in petroleum refining.
- Car exhaust.
- Tobacco smoke.
- Polluted air and water near chemical, plastic, or rubber plants.
The cancer connection
Studies have consistently found a link between 1,3-butadiene exposure at work and a higher rate of leukemia.
The International Agency for Research on Cancer (IARC) sits within the World Health Organization and grades the strength of cancer evidence. It places 1,3-butadiene in Group 1, carcinogenic to humans. That is the strongest evidence category. It means there is enough evidence that it can cause cancer in people. The US National Toxicology Program agrees. It lists 1,3-butadiene in its Report on Carcinogens as known to be a human carcinogen.
Hazard is not the same as risk
Hazard and risk answer different questions. Hazard asks: can this cause cancer under some conditions? Risk asks: how likely is cancer for me? The Group 1 label on 1,3-butadiene is a hazard label. Your risk depends on the amount you breathe, over how many years, and other factors. Two agents with the same label can carry very different real-world risks.
How to lower your exposure
- Follow the workplace exposure limits that OSHA sets out.
- Rely on ventilation and other controls in the industries that use it.
- Avoid tobacco smoke, including secondhand smoke.
- Cut down on time spent in heavy car exhaust where you can.
Set any one exposure against the whole picture. See our overview of cancer prevention and what raises cancer risk.
The bottom line
1,3-Butadiene is a known human carcinogen (IARC Group 1). The clear risk shows up at work, in plants that make or use it. Away from those jobs, tobacco smoke is the source you can act on. If your job involves it, workplace controls and monitoring matter more than the label itself.
Sources
Words to know
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Common questions
Does 1,3-butadiene cause cancer?
Yes. 1,3-Butadiene 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 1,3-butadiene?
Most exposure happens by breathing the gas at work, or from vehicle exhaust and tobacco smoke.
Which cancers are linked to 1,3-butadiene?
It is most strongly linked to leukemia and other blood cancers.
How can I reduce my exposure to 1,3-butadiene?
The main steps are workplace controls and avoiding tobacco smoke.
Does a carcinogen label mean I will get cancer?
No. A classification is about hazard — whether 1,3-butadiene 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: 2026-08-11Next planned review: 2028-07-05
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How this page was created
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. We do not employ clinicians and do not intend to — our work 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 checked line by line against the sources listed on it. That confirms the sources support what the page says. 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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