The short answer
Hexavalent chromium is a form of chromium used in plating, welding, and pigments. Breathing it at work is linked to lung and nasal cancers. Ventilation, controls, and respirators reduce exposure.
Hexavalent chromium is classified as a known human carcinogen (IARC Group 1).
People are mainly exposed by breathing mists or fumes at work, such as plating and welding.
It is most strongly linked to lung cancer.
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
Chromium is a metal that exists in different forms. One form, called hexavalent chromium or chromium-6, is used in metal plating, stainless-steel welding, and some paints. Breathing it over time is linked to lung cancer.
What hexavalent chromium is
Hexavalent chromium (chromium-6) is a highly reactive form of chromium used in electroplating, stainless-steel welding, chromate pigments, and leather tanning. It gained public attention through contaminated drinking water cases.
How people are exposed
Common ways people come into contact with it:
- Working in chrome plating, stainless-steel welding, or pigment production
- Breathing mists or fumes containing chromium-6
- Some contaminated drinking water near industrial sites
The cancer connection
Hexavalent chromium is linked to lung cancer and to cancers of the nasal cavity and sinuses in exposed workers.
The International Agency for Research on Cancer (IARC), the cancer arm of the World Health Organization, places hexavalent chromium 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 hexavalent chromium 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 local exhaust ventilation for plating and welding
- Wear respiratory protection and follow OSHA chromium-6 limits
- Support monitoring of drinking water near industrial sites
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
Hexavalent chromium 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 hexavalent chromium cause cancer?
Yes. Hexavalent chromium 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 hexavalent chromium?
Most exposure happens by breathing mists or fumes at work, such as plating and welding.
▸Which cancers are linked to hexavalent chromium?
It is most strongly linked to lung cancer.
▸How can I reduce my exposure to hexavalent chromium?
The main steps are ventilation, respiratory protection, and workplace limits.
▸Does a carcinogen label mean I will get cancer?
No. A classification is about hazard — whether hexavalent chromium 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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