In general, the American Cancer Society does not determine if something causes cancer (that is, if it is a carcinogen). Instead, we rely on the determinations of other respected agencies, such as the International Agency for Research on Cancer (IARC) and the US National Toxicology Program (NTP).
The lists below are from IARC and NTP, and more information on each of these known and probable human carcinogens can be found on their websites.