Aflatoxins and Environmental Toxins
Aflatoxins are cancer-causing toxins (or poisons) found in molds that contaminate maize, corn, rice, soybeans, and different nuts. These molds are more common in warmer and tropical regions, such as countries in sub-Saharan Africa and Asia where poor storage conditions may result in mold formation. The risk of liver cancer is much higher among individuals who have long-term exposure to aflatoxins and also are chronically infected with hepatitis B or C.
Exposure to chemicals such as vinyl chloride and thorium dioxide can increase the risk of a type of liver cancer called angiosarcoma (see Types of Liver Cancer). Vinyl chloride is a chemical used in making certain plastics. Thorium dioxide is a chemical that in the past was injected as part of certain x-ray tests. In the United States, thorium dioxide is no longer used, and strict regulations minimize the exposure to vinyl chloride.
Long-term exposure to drinking water that is contaminated with naturally occurring arsenic increases the risk of some types of liver cancer. This is more common in parts of East Asia, but might also occur in the United States, such as in parts of Maine, Michigan, Minnesota, South Dakota, Oklahoma, and Wisconsin.