riverbank army ammunition plant


The 173-acre Riverbank Army Ammunition Plant site has been used to manufacture materials, including cartridge cases, grenades, and projectiles, since 1951. The site comprises the 145-acre main facility and four unlined industrial waste treatment ponds in the flood plain of the Stanislaus River, located approximately 1 1/2 miles north of the main facility. In 1942, the Aluminum Company of America built the site plant as an aluminum reduction facility to supply the military. The plant closed in 1944 and reopened in 1951, with Norris Industries, Inc. as the operating contractor. The plant was identified for closure under the 2005 Base Realignment and Closure round. As of 2010, the U.S. Army is negotiating property transfer conditions with the City of Riverbank. As a result of industrial activities, the site has generated corrosive wastes, solvents, and wastewater containing heavy metals. Chromium and cyanide have been released onto the property and have subsequently leached into the groundwater, and over the years the contaminant plumes have migrated beyond the installation boundary. In addition, a variety of waste and debris were burned or disposed of on the ground surface and in trenches in a landfill area at the facility. Studies also have determined that sediments in the waste treatment ponds contain elevated levels of zinc. Overflows from the ponds have dumped into the Stanislaus River, and the river has occasionally overflowed into the ponds during periods of flooding. Approximately 13,700 people obtain drinking water from public and private wells within 3 miles of the site, and at least 3,500 acres of nut and fruit orchards are irrigated partially by groundwater. The Stanislaus River is used for irrigation and recreational activities.

Hazardous Ranking Score

64 / 100

A score of 28.5 or higher qualifies a site for the Superfund National Priority List.

Regional Contact

Region 9
Phone: (415) 947-4251

Contact Region



Site Inspection
Preliminary Assessment
Final Listing On NPL

Contaminants & Health Effects

      Endocrine Disrupter
      Reproductive Toxin
      Persistent, bioaccumulative and toxic


        African American
        American Indian and Alaska Native
        Native Hawaiian


        People living
        within a 1 mile radius


        Average Income


        Occupied homes

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