What are the most important categories of organ damage caused by toxic chemicals? From animal experiments, case reports and epidemiological studies, we now have fairly complete information about the potential adverse effects of these agents. Contact dermatitis is the most common agent-induced occupational disease. Hematotoxins cause anemia. Hepatoxins cause liver injury. Carcinogens are classified as known, probable or possible by the International Agency for Research on Cancer (IARC).