Riverbank Army Ammunition Plant

Riverbank Army Ammunition Plant is a 173-acre former munitions manufacturing facility located near Modesto in Stanislaus County, California. The site was originally built in 1942 as an aluminum reduction plant before the Army converted it for ordnance work, and it produced steel cartridge cases, grenades, projectiles, and related munitions beginning in 1951. The plant supported manufacturing through the Korean and Vietnam War eras until production ceased in 1981. In 2005 the Base Realignment and Closure Commission recommended closure, and a local redevelopment authority later assumed control of much of the property. Decades of industrial operations left a legacy of environmental contamination that remains under active management.

Because of the plant's long history of metal forming, plating, and munitions production, environmental investigations have identified several substances of concern in groundwater, soils, sediments, and building materials at the site. The following contaminants have been documented through EPA and state oversight.

1. Heavy metals. Industrial operations such as metal plating and finishing generated wastes containing chromium and other heavy metals, which were discharged to unlined treatment ponds and reportedly leached into groundwater. Exposure to certain heavy metals has been associated with a range of health concerns, and the contamination here prompted long-term groundwater treatment.
2. PCBs. Large production buildings at the plant were constructed with Galbestos siding and roofing that contained high levels of polychlorinated biphenyls, and PCBs were also detected in concrete, paint, equipment, and dust across the complex. PCBs are persistent compounds, and concerns about potential exposure have been raised in connection with various long-term health effects.
3. Asbestos. The Galbestos building materials and other older construction at the facility are associated with asbestos, a fibrous mineral once widely used for insulation and fireproofing. Inhalation of asbestos fibers has been linked to serious respiratory conditions, which is why demolition and abatement work at such sites is closely regulated.
4. Solvents. Cleaning and degreasing operations typical of munitions manufacturing involved industrial solvents, which were among the wastes generated on the property. Some solvents have been associated with potential health concerns, and their presence contributed to the site's groundwater and soil investigations.

Riverbank Army Ammunition Plant was added to the EPA National Priorities List as a Superfund site on February 21, 1990. Cleanup actions have included construction of a landfill cap completed in 1995, a groundwater treatment system that began operating in 1996, and the removal and off-site disposal of thousands of tons of PCB-contaminated equipment. The site is overseen by the EPA in coordination with the California Department of Toxic Substances Control and the Army, and cleanup, monitoring, and ongoing PCB remediation continue under institutional controls that restrict certain uses of the property.

Veterans and civilian workers who served at or near Riverbank Army Ammunition Plant may wish to stay informed about the site's environmental history and ongoing remediation. Anyone with questions about possible exposure and related benefits is encouraged to speak with the U.S. Department of Veterans Affairs and a personal healthcare provider, who can offer guidance based on individual circumstances.