The National Priorities List (NPL) is a list maintained by the United States Environmental Protection Agency (EPA) that identifies sites contaminated with hazardous substances. It is part of the Superfund program, which aims to clean up these polluted locations to protect public health and the environment. Sites on the NPL are prioritized based on the level of risk they pose to human health and the environment. Being placed on the NPL allows for federal funding and resources to be allocated for cleanup efforts. The list is updated regularly, and sites can be added or removed based on ongoing assessments and cleanup progress. The NPL plays a crucial role in addressing environmental hazards across the country.