Contaminants must be identified and their potential threat assessed, sites must be characterized and investigated, and media must be treated or removed to address contamination. EPA uses a wide variety of technologies in these activities to ensure contaminants are either removed from the site or are treated so they no longer pose a threat to human health and the environment. Information on these technologies and methodologies for cleaning up contaminated sites has been provided here for technical staff, regulators, site owners, and researchers.