Asbestos is a carcinogen. The roof of this house is made of asbestos.

Frozen benzene. Benzene is a carcinogen

Aspergillus flavus, a kind of mould, produces Aflatoxin B1, which is a carcinogen.

Carcinogens are substances that cause cancer. Sometimes radiation or radionuclide are also considered carcinogens. A common example of a carcinogen is tobacco smoke. Carcinogens come from both natural and man-made substances.