General Information About Carcinogens

Here you can learn how potential carcinogens are tested and classified, find lists of known and possible carcinogens, and learn about cancer clusters.

Cancer Clusters

More than 1,000 suspected cancer clusters are reported to state health departments each year. But just what is a cancer cluster?

Known and Probable Human Carcinogens

This page provides lists of substances and exposures that are known or suspected to cause cancer. To help put these lists into context, some related information is included on how different agencies and groups test and classify possible carcinogens.