Superfund or Comprehensive Environmental Response, Compensation, and Liability Act of 1980 (CERCLA) is a United States federal law designed to clean up sites contaminated with hazardous substances and pollutants. It authorizes federal natural resource agencies, primarily the Environmental Protection Agency (EPA), states and Native American tribes to recover natural resource damages caused by hazardous substances, though most states have and most often use their own versions of CERCLA. CERCLA created the Agency for Toxic Substances and Disease Registry (ATSDR). EPA may identify parties responsible for hazardous substances releases to the environment (polluters) and either compel them to clean up the sites, or it may clean up itself using the Superfund (a trust fund) and cost recovered from polluters by referring to the U.S. Department of Justice. The key difference between the authority to address hazardous substances and pollutants or contaminants is that the cleanup of pollutants or contaminants, which are not hazardous substances cannot be compelled by unilateral administrative order.