A substance that can cause or contribute to cancer.
A carcinogen is an agent with the capacity to cause cancer in humans. Carcinogens may be natural, such as aflatoxin, which is produced by a fungus and sometimes found on stored grains, or manmade, such as asbestos or tobacco smoke. Carcinogens work by interacting with a cell's DNA and inducing genetic mutations.
Carcinogen has been defined 25 different ways in documents like IAQ Building Education and Assessment Model, A Guide to The Globally Harmonized System of Classification and Labeling of Chemicals, Glossary, FRTR Glossary, and 7 more.