In Chemicals and Cancer: Establishing Causation through Medical Toxicology, chemical toxicology expert witness Nachman Brautbar, M.D. writes:
Chemical exposure and cancer date back several thousand years. The famous occupational physician, Ramazzini, was one of the first to describe examples of occupationally-induced cancers.
In the last 20 years, benzene has been shown to be a carcinogenic agent causing leukemias, lymphomas, and other hematological cancers. Other chemicals, such as chlorinated hydrocarbons, asbestos, and hexavalent chromium, have been shown to be carcinogenic.
The observation that despite reduction in cigarette consumption, despite reduction in fatty food consumption and despite improved screening procedures, cancers of the lung, breast, and blood system is on the rise and is by and large attributed to a combination of environmental chemical factors imposed on the genetic makeup of the individual.