Contaminated sites often threaten public health or the environment and can cause economic hardship to people and communities. Contaminated sites may be associated with military, commercial or industrial activities, including oil production and storage operations, mining, and a wide variety of smaller enterprises where hazardous materials were used. In some instances, groundwater and surface waters have become so polluted that human health or the environment have been impaired or placed at risk. Some of these pollutants are known to cause increased incidences of cancer while others may contribute to health problems. Many different types of hazardous substances are found at contaminated sites in Alaska.
Sites contaminated by petroleum products are by far the most common.
Aromatic compounds also tend to be the most easily dissolved in water and are responsible for making many drinking water sources in the state unfit for human use. Diesel fuels and the heavier petroleum products, although hazardous, have a much lower content of the most harmful constituents. Other contaminated sites can have chlorinated solvents, heavy metals, synthetic organic pesticides, non-chlorinated solvents, and inorganic acids and bases. The banned chlorinated pesticide DDT has also been found at several sites. Heavy metal contamination can also pose a serious threat to public health.