Nammo Defense Systems Inc. Site Environmental Remediation Project

Administrative Order on Consent

This website was established by Nammo Defense Systems (NDS) as required by an Administrative Order on Consent (Order). The Order dated February 9, 2021 is an enforceable agreement between the United States Environmental Protection Agency (EPA) and NDS that provides a framework for environmental investigation and cleanup of the land and groundwater at and around the NDS facility in northeast Mesa, Arizona. This website will serve as a public repository for information regarding the environmental cleanup project. Although the Order is between EPA and NDS, EPA is working in partnership with EPA-designated stakeholders, including the Arizona Department of Environmental Quality (ADEQ) and the Salt River Pima Maricopa Indian Community’s (SRPMIC) Environmental Protection and Natural Resources Division to oversee the environmental work at this facility.

Site History

Talley Industries Inc. operated in Mesa from 1960 until the mid-1980’s. Talley specialized in the design, development and manufacture of ammunition and energetic material solutions for defense and commercial applications. In 1984, they became Talley Defense Systems, Inc. and continued operations until 2007. Nammo Group currently owns the original company and operates under NDS. The facility in present day consists of approximately 534 acres of land owned by the State of Arizona. It is located about 20 miles east-northeast of downtown Phoenix in the northern part of Mesa in Maricopa County, Arizona (See Figure 1).

Historical Release Areas

The environmental regulatory history of the facility includes two identified historical release areas: the former Water Bore-Out (WBO); and the former Thermal Treatment Unit (TTU). The TTU is currently being managed under the Order issued by the United States Environmental Protection Agency due to concerns related to the contamination migrating onto SRPMIC’s land.

Former TTU

The former TTU site is located within the current NDS facility approximately 1.25 miles north-northeast of the intersection of East Thomas Road and North Higley Road, Mesa AZ (see Figure 1). Contaminants of concern (COC) in this area include lead, perchlorate, volatile organic compounds (VOCs) and 1,4-dioxane. NDS has initiated multiple interim cleanup measures including source area soil removal, an in-situ biological injection pilot study, and the installation of a groundwater pump and treat system. The former TTU is no longer in use and a present day photo of the site, taken on 5/26/2021, can be seen in Figure 2. NDS has also established a network of ground water monitoring wells on and around the former TTU site to monitor the COCs as well as a network of extraction wells as part of the pump and treat system.

Former WBO

The former WBO site occupies approximately 100 acres of land within the current NDS facility and is located northeast of  the intersection of Greenfield Road and the Loop 202, Mesa AZ (see Figure 1). When in operation, the WBO facility used a high-pressure water jet to remove waste material from manufactured components. Presently, NDS is working under the regulatory oversight of the Arizona Department of Environmental Quality (ADEQ) and working within a Voluntary Remediation Program (VRP) to clean the WBO site. NDS has proactively initiated a pump and treat system using two extraction wells located on the site of the former WBO, Figure 3. A fluidized bed reactor (FBR), Figure 4, is used to treat the extracted water from the two wells. After treatment, the clean water is directed to the FBR ponds, Figure 5, where it is then allowed to re-enter the environment.

Further Resources

United States Environmental Protection Agency Website

Arizona Department of Environmental Quality Website

Arizona Department of Environmental Quality Voluntary Remediation Program Website

Arizona Department of Environmental Quality RCRA Website

Last Update: 09/14/2023