European Code Against Cancer - Which are the most important chemical substances in the environment that may cause cancer, and which cancers do they cause?

Some of the most important chemical substances in our environment in the countries of the European Union are pollutants contaminating the outdoor and indoor air, including all forms of asbestos, benzene, diesel engine exhaust and polycyclic aromatic hydrocarbons (PAHs); water and food contaminants such as arsenic and inorganic arsenic compounds; and persistent organic pollutants (POPs), such as dioxins. Air pollution has recently been classified by the International Agency for Research on Cancer (IARC) as a mixture of multiple pollutants that may cause cancer.

There are a number of cancer types for which there is sufficient evidence that they are caused by chemical substances found in the environment. Cancers of the lung, urinary bladder, and skin, as well as mesothelioma (cancer of the cells of the mesothelium, the protective lining that covers the chest, the abdomen, and the space around your heart), leukaemias, and lymphomas, are the most important types (Figure 1).

Figure 1: Main cancer sites related to chemical substances in the environment.

The International Agency for Research on Cancer (IARC) continuously assesses the potential of chemicals and other substances to cause cancer in humans. Such assessments, by IARC or by other international or national authorities, are usually the first step in cancer prevention and enable decision-makers to institute measures to reduce or eliminate human exposure to known – or sometimes also suspected – cancer-causing substances.

Other relevant environmental exposures are second-hand smoke (or involuntary, “passive” smoking), radon, and ultraviolet (UV) radiation from the sun.