The Church Rock Mill site is a a former uranium ore processing mill and tailings disposal area operated by United Nuclear Corporation that was placed on the National Priroties List (NPL) by the U.S. Environmental Protection Agency on 9 September 1983. The NPL is the list of national priorities among the known releases or threatened releases of hazardous substances, pollutants, or contaminants throughout the United States and its territories.

The NPL is part of the Superfund program, the common name for the United States environmental policy officially known as the Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA), enacted by the United States Congress on December 11, 1980 in response to the Love Canal and Times Beach disasters. The Superfund law was created to protect people, families, communities and others from heavily contaminated toxic waste sites that have been abandoned.