Skip to main content

Arizona Army National Guard Camp Navajo | Site History

1942: Camp Navajo was established and was originally known as the Navajo Army Depot. The facility operated as a reserve supply depot for the receipt, shipping, storage, surveillance, minor maintenance and demilitarization of ammunition/explosives and assigned commodities. The OB/OD area was formerly used for demilitarization and land disposal of obsolete and unserviceable conventional ammunition, explosives, and limited chemical warfare agents.

1979: Improper disposal occurred in the OB/OD area at sites including the trinitrotoluene (TNT) washout lagoons and the former White Phosphorus Detonation and burn area (a.k.a. Chemical Canyon). Four landfills containing ordnance and visible unexploded ordnance (UXO) are located in the OB/OD area. Environmental studies of the facility began.

1982: Operational control of the base was transferred under an intra-State support agreement from the Secretary of the Army to the AZ Air National Guard (ARNG). After the transfer, the missions for the National Guard were training, continuing depot activities and facilities maintenance.

1993: Operational control was transferred under the Base Realignment and Closure Act of 1988 (BRAC 1) to the AZ ARNG, and the name was changed to Camp Navajo. The installation continues as a major training site, and also performs a depot-level storage service for the Department of Defense (DoD), other government, and civilian entities. As a condition of transfer, the Army maintained responsibility for cleanup activities at the facility.

1994: The Army’s demilitarization activities in the OB/OD Area were regulated under HTRCRA interim status. Demilitarization activities ceased in September 1994 in connection with the closure of Camp Navajo under BRAC 1. A closure plan was submitted to ADEQ, which was determined to be insufficient.

Contamination at the facility did not qualify the site for inclusion on the U.S. Environmental Protection Agency's (EPA) NPL. However, the facility is subject to all state and federal laws and is being cleaned up to federal standards as part of the DoD’s IRP.

1995 - 2002: Between 1995 and 2001, the Army environmental center conducted a closure plan investigation to collect sufficient data to support an appropriate closure plan. In 1998, the Army environmental center submitted an investigation report, but ADEQ asked for additional sampling and site cleanup. Between 1998 and 2001, very little progress was made on further investigation of the OB/OD area because of Army funding. In February 2001, a preliminary geophysical report was submitted to ADEQ that revealed potential UXO in the OB/OD area was worse than that previously suspected.

2002: In February, a SAG was formed to assist the NGB with stakeholder concerns. The SAG consisted of members from agencies such as the U.S. Fish and Wildlife Service, ADEQ, the Arizona Game and Fish Department, the U.S. Forest Service, the AZ ARNG, as well as three community members. Remedial activities in the OB/OD area included: repair and replacement of the fence around the OB/OD area, conducting an airborne ordnance detection survey, posting warning signs around the OB/OD area in English and Spanish, conducting an archive search report, performing detonation pit sampling, consulting with the U.S. Fish and Wildlife Service, conducting a biological survey, updating the community relations plan, and distributing a hunting advisory flyer.

Camp Navajo is home of several threatened and endangered species, including the bald eagle, northern goshawk, ferruginous hawk, osprey, peregrine falcon, the Mexican spotted owl and the Arizona toad. Other inhabitants include the pronghorn and elk. A protected activity center and critical habitat for the Mexican spotted owl is located in the south-eastern portion of the OB/OD Area. Due to the weather in the Bellemont area, the field season would normally last from May thru November. Because the Mexican spotted owl’s mating season is from March 1st to August 31st, conservation measures are implemented in consultation with the U.S. Fish and Wildlife Service.

2003: During a soil and surface water sampling event in January, submunitions were encountered in the historical OB/OD Area. In response to this finding, the area was closed and access was prohibited.

The NGB obtained approval of a Department of Army waiver, which allowed access back into the area for environmental cleanup activities. The NGB prepared the following documents for ADEQ’s review: 1) background and Remediation Metal Standards technical memorandum, 2) an archive search report, 3) the draft-final report Airborne Geophysical Survey for unexploded ordnance, 4) the community relations plan, and 5) the final draft summary letter report of the Open Detonation Pit Sampling event.

During the summer, the NGB completed a surface sweep of the ground in the former White Phosphorus open detonation and burn area (aka Chemical Canyon, NAAD 03) which allowed for a remedial investigation (RI) and feasibility study (FS) to be performed Items retrieved were detonated in a contained detonation chamber and wastes were properly disposed. A geophysical survey was performed after the sweep was completed. The geophysical survey was used to determine areas that may have been used for open burning or detonation of white phosphorus rounds.

2004: In July, the NGB began a two-year surface water and groundwater investigation in the OB/OD area. Perchlorate was analyzed in this investigation, and with the exception of surface water in the open detonation pits, the results were non-detect for contaminants of concern. In October, the NGB began a soil investigation in the NAAD 02 (aka Open Detonation Pits) area. Both surface and subsurface samples were collected and reported in the RI report. In October, the NGB began investigations at four of the open burn areas (NAADs 05, 06, 08B, and 09D) that were operated under RCRA interim status. The investigation consisted of surface and subsurface soil sampling, and additional trenching in NAAD 08B to investigate numerous historical trenches.

2005: The removal action for the landfill began in January and was completed in September. During the open burn area’s Phase I sampling in April, NAADs 05 and 06 had contaminant levels above regulatory levels which, led to a Phase II vertical extent investigation in October.

In June, ADEQ met with the NGB to discuss investigation activities in NAADs 01, 04, 07, 08A, 09A, 10, and E76. These sites were not operated under the RCRA interim status permit and are being investigated under a performance-based contract. ADEQ received the work plan and field work began in October.

2006: NGB continued investigations at NAADs 01, 02, 04, 05, and E76, and also conducted interim removal actions to remove lead, arsenic, and TNT-impacted soil. Investigation and removal action reports, including human health and ecological risk assessments, were prepared for numerous sites within the OB/OD area.

2007: Field activities for summer and fall included soil screening at NAAD 02 and NAAD 09C for soils being transported off site for disposal, screening of soils at NAAD 09C for backfilling into the NAAD 02 area, surface Munitions of Explosive Concern (MEC) clearance activities in NAAD 01 and NAAD 02, and continued inspections and sampling of the OB/OD area. An annual site visit by ADEQ occurred which included a quality assurance, quality control inspection of field activities in the OB/OD area.

Several reports were submitted for the OB/OD area including a revised master work plan, a revised surface MEC removal site-specific work plan, the 2006 OB/OD surface and groundwater annual monitoring report, the NAAD 02 site-specific RI report, the NAAD 02/03 characterization report, the final NAAD 05 Human Health and Ecological Risk assessment, the draft NAAD 06 Human Health and Ecological Risk assessment, the NAAD 09C Removal Action report, the Construction Completion report and Risk Screening Evaluation for NAAD 01, the final NAAD 20 characterization report, and quarterly MEC inventory and accountability reports.

ADEQ also reviewed the LTM groundwater monitoring report for NAADs 11B, 14D, 14G, 40 and 43. ADEQ recommended the continuing monitoring of perchlorate in the wells. Camp Navajo continued to conduct groundwater monitoring and reporting at all LTM sites.

2008: No field activities were conducted. The NGB and ADEQ focused on submitting and approving reports and preparing for field activities beginning in spring 2009 and post-closure beginning in fall 2009.

2009: Twenty vadose zone monitor wells were installed in the OB/OD area around NAAD 02 to prepare the site for post-closure under RCRA. Final MEC remediation activities continued until September. After that the site began the transfer to the ADEQ Hazardous Waste Permits Unit to undergo RCRA post-closure. Remediation activities for the summer included surface sweeps and MEC removal near NAAD 02, the screening and backfilling of stockpiled soil into NAAD 02, and the submission of several decision documents to complete the closure.

2010: All remaining field activities including screening and sampling of stockpiled soil, backfilling the NAAD 02 pits, on-site detonation of all MEC, and collecting all scrap Munitions Debris (MD) for off-site recycling were completed in the summer. The munitions response work area (MRWA) 02 MEC EE/CA was approved in the winter. ADEQ and the NGB began a series of meetings to prepare the site to undergo RCRA post-closure.

Vadose zone monitoring (OB/OD area around NAAD 02), year 1 results, were reported during September. Additional monitoring (Year 2 monitoring) was recommended as part of the initial transition toward RCRA post-closure oversight.

2011: Vadose zone monitoring (OB/OD area around NAAD 02), year two results, were reported. NGB explored funding sources to continue transition steps toward RCRA post-closure oversight.

2012: Budget limitations resulted in delayed actions during the year. Anticipated activities were re-scheduled to occur in the future. ADEQ and the NGB initiated transition steps toward RCRA post-closure oversight. NGB’s post-closure permit application remained in initial discussion between NGB and ADEQ’s Hazardous Waste Permits Unit.

2013: Budget limitations resulted in delayed actions during the year. Anticipated activities were re-scheduled to occur in the near future. Additional vadose zone monitoring in the OB/OD area of NAAD 02 region is planned by NGB. ADEQ will review a NGB-developed NAAD 02 risk assessment and an NGB-developed NAAD 02 decision document after appropriate data has been collected. The NGB continued the initial transition steps toward RCRA post-closure oversight. NGB’s post-closure permit application discussion continues between NGB and ADEQ’s Hazardous Waste Permits Unit.