A recent release from the Agency for Toxic Substances and Disease Registry, an agency of the US Department of Health and Human Services, lists the top twenty hazardous substances to the public. Each substance's page answers what it is, what happens when it enters the environment, how the public may be exposed, how it could affect your health, and more. For example, arsenic, which was found to be the most toxic, is mainly used to preserve wood and in pesticides, while potentially causing everything from a sore throat to cancer. The twenty substances are part of a larger list of 275 from the 2001 Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA) Priority List, to which visitors can link and find additional information.