The short answer
Coal tar and coal-tar pitch come from processing coal and are used in roofing, paving, and some medicines. Heavy exposure is linked to skin and lung cancers. Occupational controls and careful medical use reduce risk.
Coal tar and coal-tar pitch is classified as a known human carcinogen (IARC Group 1).
People are mainly exposed by skin contact and breathing fumes, mainly in industrial jobs.
It is most strongly linked to skin and lung 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
Coal tar is a thick, dark liquid made when coal is heated. It is used in roofing, road paving, and some skin treatments. Long, heavy exposure — mostly at work — is linked to skin and lung cancers.
What coal tar and coal-tar pitch is
Coal tar and coal-tar pitch are byproducts of turning coal into coke and gas. They contain polycyclic aromatic hydrocarbons (PAHs), which are the cancer-causing part. Coal tar is used industrially and, in low concentrations, in some medicated shampoos and ointments.
How people are exposed
Common ways people come into contact with it:
- Working in roofing, paving, aluminum production, or coal-tar production
- Skin contact and breathing fumes from hot coal-tar products
- Long-term, high-concentration use of coal-tar skin products (medical use is usually low-dose)
The cancer connection
Heavy coal-tar exposure is linked to skin cancer and lung cancer, and coal-tar pitch is linked to bladder cancer in some settings. The cancer-causing PAHs are the main concern.
The International Agency for Research on Cancer (IARC), the cancer arm of the World Health Organization, places coal tar and coal-tar pitch in Group 1, carcinogenic to humans — the strongest evidence category, meaning there is enough evidence that it can cause cancer in people. In the United States, the National Toxicology Program's Report on Carcinogens lists it as known to be a human carcinogen.
Hazard is not the same as risk
It helps to separate two ideas that are easy to mix up: hazard and risk. When an agency lists coal tar and coal-tar pitch as a carcinogen, it is making a statement about hazard — whether the substance is capable of causing cancer under some conditions. It is not, by itself, a statement about your personal risk, which depends on how much you are exposed to, for how long, and other factors. Two substances in the same group can carry very different real-world risks. The label answers "can it cause cancer?" — not "how likely is it to cause cancer for me?"
How to lower your exposure
- Use protective clothing, gloves, and respiratory protection in industrial settings
- Limit skin contact and fume exposure with hot coal-tar products
- Use medicated coal-tar products as directed, and ask your doctor if concerned
If you are looking at your overall cancer risk, small, steady steps add up. See our overview of cancer prevention and what raises cancer risk to put any single exposure in context.
The bottom line
Coal tar and coal-tar pitch is a known human carcinogen (IARC Group 1). The most important thing you can do is understand where exposure comes from and take reasonable steps to reduce it, without losing sleep over a single label. Focus your energy on the biggest, most controllable risks in your own life.
Words to know
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Common questions
▸Does coal tar and coal-tar pitch cause cancer?
Yes. Coal tar and coal-tar pitch 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 coal tar and coal-tar pitch?
Most exposure happens by skin contact and breathing fumes, mainly in industrial jobs.
▸Which cancers are linked to coal tar and coal-tar pitch?
It is most strongly linked to skin and lung cancers.
▸How can I reduce my exposure to coal tar and coal-tar pitch?
The main steps are protective equipment and limiting skin and fume contact at work.
▸Does a carcinogen label mean I will get cancer?
No. A classification is about hazard — whether coal tar and coal-tar pitch 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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