The National Priorities List (NPL) is the priority list of hazardous waste sites in the United States eligible for long-term remedial investigation and remedial action (cleanup) financed under the federal Superfund program. Environmental Protection Agency (EPA) regulations outline a formal process for assessing hazardous waste sites and placing them on the NPL. The NPL is intended primarily to guide EPA in determining which sites are so contaminated as to warrant further investigation and significant cleanup. As of 2022, 1333 sites are on the list, and 43 sites have been proposed for listing. 448 sites have been deleted from the list. Process for listing The Comprehensive Environmental Response, Compensation, and Liability Act of 1980 (CERCLA), also known as "Superfund", requires that the criteria provided by the Hazard Ranking System (HRS) be used to make a list of national priorities of the known releases or threatened releases of hazardous substances, pollutants, or contaminants in the United States. This list is Appendix B of the National Contingency Plan, known as the "National Priorities List." Hazardous waste sites become eligible for CERCLA/Superfund cleanup when EPA receives a report of a potentially hazardous waste site from an individual, state government, or responsible federal agency. EPA will first enter the potentially contaminated facility into a database known as the Comprehensive Environmental Response, Compensation, and Liability Information System (CERCLIS). Then, either EPA or the state in which the potentially contaminated facility is located will conduct a preliminary assessment, which decides if the facility poses a threat to human health and/or the environment. If the preliminary assessment shows the possibility of contamination, EPA (or the state under agreement with EPA) will conduct a more detailed site inspection. EPA then uses the HRS to review any available data on the site to determine whether its environmental or health risks are enough to qualify the facility for a Superfund NPL cleanup. Generally, facilities with overall scores of 28.50 and greater on the HRS are eligible for the NPL. Another way facilities can be included in the NPL is if a state or territory designates one top-priority site within its jurisdiction, regardless of the site's HRS score. The last way a site can be included in the NPL is if it meets the following three requirements: The Agency for Toxic Substances and Disease Registry has issued a health advisory that recommends removing people from the facility. EPA determines that the site