2024: The United States Air Force (USAF) completed a per- and polyfluoroalkyl substances (PFAS) Site Inspection Addendum focused on off-base municipal drinking water supply well impacts from Aqueous Film Forming Foam (AFFF) Release Areas.

The perfluorooctanoic acid (PFOA) and perfluorooctane sulfonate (PFOS) remedial investigation (RI) field activities continue at identified release areas to confirm the source and delineate the impact.

2023: The fifth Five Year Review (FYR) was released. The FYR determined that all remedies are functioning as designed, continue to be protective of human health and the environment, and control exposure pathways that could result in unacceptable risks. It was also noted the protectiveness should be reevaluated based on the results of the PFAS remedial investigation in the future. The next FYR will be due in 2027.

The USAF completed a Site Inspection Addendum focused on off-base private drinking water well impacts from AFFF Release Areas.

2022: The Explanation of Significant Differences to the Record of Decision (ROD) and evaluation for site closure were completed for three Long-Term Monitoring sites: 

• RW002; Low-Level Radioactive Waste Burial Pit 
• SS042; Bulk Fuel Storage Area
• DP013; Drainage Ditch Disposal Area

An Action Memorandum detailing the Emergency Removal Actions and Time Critical Removal Actions for PFOA and PFOS impacted drinking water wells was released by the Air Force Civil Engineer Center (AFCEC) and posted for public comments in February. A temporary ion-exchange treatment system was installed for impacted Valley Utilities Water Company wells and two residences were connected to the public water system. Ongoing coordination continues with connecting the third impacted residence to the public water system.

The PFOA and PFOS RI field activities continue at identified release areas to confirm the source and delineate the impact. 

2021: Luke Air Force Base command personnel released notifications that mitigation actions were in place at known impacted water supply utilities and privately owned water wells. Water supply utilities and privately owned water wells will continue to be sampled over an expanded area out to 4 miles downgradient from Luke Air Force Base.

PFOA and PFOS RI activities continue at identified release areas to confirm the source and delineate the impact.

2020: Multiple sites were closed:  

• FT-07E; North Fire Training Area – East Side 
• SD-20; Oil/Water Separator Canal and Earth Fissure 
• SD-38; Oil/Water Separator at the Old Auto Body Shop 
• ST-18; Former Liquid Waste Storage Facility (Facility 993)

Monitoring and inspections continued, as needed, at other locations. 

A remedial action work plan for a more efficient clean up was initiated for TU-44; Waterdog Recreational Annex. 

AFCEC initiated an RI to confirm and delineate PFOA and PFOS impact. AFCEC also continued with the Expanded Site Investigation and explored the potential to sample water systems and privately owned wells out to 4 miles downgradient from Luke Air Force Base.

2019: Exploratory excavation to remove waste buried in place was performed at RW-02; Wastewater Treatment Plant Annex Landfill. 

The USAF released the AFFF Release Areas Final Site Inspection Report, Luke Air Force Base and Gila Bend Auxiliary Airfield. The 2019 Site Investigation results showed PFOA and PFOS concentrations in select soil and groundwater samples. The USAF plans additional Site Inspection.  

The 2019 results prompted AFCEC to initiate an Expanded Site Inspection focused on requesting access to privately owned wells within 1 mile downgradient of Luke Air Force Base.

2018: Groundwater monitoring and institutional control (IC) inspections continued.

2017: The fourth FYR was released. The FYR determined that all remedies are functioning as designed, continue to be protective of human health and the environment, and control exposure pathways that could result in unacceptable risks.

The fourth FYR report discusses the following 13 sites:

• DP-13; Drainage Ditch Disposal Area 
• DP-23; Old Surface Impoundment West of Facility 993 
• FT-07; North Fire Training Area – West Side 
• FT-07E; North Fire Training Area – East Side 
• LF-03; Outboard Runway Landfill 
• LF-14; Old Salvage Yard Burial Site 
• LF-25; Northwest Landfill 
• RW-02; Wastewater Treatment Plant Annex Landfill 
• SD-20; Oil/Water Separator Canal and Earth Fissure 
• SD-38; Oil/Water Separator at the Old Auto Body Shop 
• SS-42; Bulk Fuels Storage Area 
• ST-18; Former Liquid Waste Storage Facility (Facility 993)
• TU-44; Waterdog Recreational Annex

2016: Announced a Health Advisory for PFOA and PFOS. In response, the AFCEC performed a Site Investigation focused on historic AFFF storage and release areas.

2014 – 2015: Groundwater monitoring and IC inspections continued. 

Soil sampling activities were performed at sites FT-07E and ST-18 in the later part of 2014. Results were submitted to ADEQ in 2015. Site SS-42 continue to undergo annual groundwater monitoring sampling events.

2013: Groundwater monitoring and IC inspections continued. The performance-based remediation contract was awarded in September. The annual long term monitoring activities were performed. Results for the annual groundwater monitoring reports concluded that results were consistent with previous year’s annual monitoring data.

2012: The third FYR report was finalized in September. It summarized the status of the remedies implemented at ten sites identified in the Operable Unit (OU)-1 and OU-2 ROD which included soil treatment, source capping, groundwater monitoring, gamma radiation monitoring, and ICs. The third FYR report discusses the following ten sites that required a remedy, as determined from the results of the RI:

• Drainage Ditch Disposal area (DP-13)
• Eastern portion of North Fire Training area (FT-07E)
• Outboard Runway Landfill (LF-03)
• Old Salvage Yard Burial site (LF-14)
• Northwest Landfill (LF-25)
• Wastewater Treatment Annex Landfill (RW-02)
• Oil/Water Separator at Auto Body Shop (SD-38)
• Bulk Fuels Storage area (SS-42)
• Former Liquid Waste Storage Facility (Facility 993) (ST-18)
• Old Surface Impoundment West of Facility 993 (DP-23)

The assessment conducted as part of this FYR found that the remedies required at the OU-1 and OU-2 sites were implemented in accordance with the requirements of the RODs. All remedies are functioning as designed, continue to be protective of human health and the environment, and control exposure pathways that could result in unacceptable risks. 

2010 – 2011: Annual reports were reviewed by ADEQ and EPA, which included the Potential Source of Contamination (PSC) ST-18 concrete cap inspection report, the annual radiation monitoring report and the annual groundwater monitoring report. Results for the PSC ST-18 concrete cap inspection report concluded that minor repairs to the cap were required in order to maintain its integrity including sealing cracks and gaps. It was recommended that the cap be replaced in the future. Results for the annual radiation monitoring report concluded that the containment structure for the radiological material remains intact and that the surrounding soil does not appear to have been impacted by this material. Results for the annual groundwater monitoring reports for 2010 and 2011 concluded that results were consistent with previous year's annual monitoring data, with a slight increase in groundwater elevation. In 2011, the groundwater elevation of the site was approximately 240 feet below ground surface (bgs).

2009: An interim annual groundwater monitoring report summarizing the results of the annual groundwater monitoring activities was conducted at sites ST-18 and SS- 42 as part of the USAF Environmental Restoration Program (ERP). The primary objectives of the groundwater long-term monitoring (LTM) were to document the presence or absence of groundwater contamination in accordance with the OU-1 and OU-2 RODs. Groundwater level measurements and groundwater sampling was conducted in May. The results of the annual groundwater monitoring event conducted were consistent with previous years’ annual monitoring data.

The Interim Annual Gamma Radiation Monitoring report (also part of the USAF ERP) summarized the results of the annual gamma radiation monitoring activities that were performed at site RW-02. Gamma radiation measurements were collected from five existing monitor points. The measurements collected during this monitoring event remain consistent with previous years’ monitoring events. The measurements recorded from monitoring points MP-1, MP-2, MP-3, and MP-4 did not exceed the action level of twice the background readings. The measurements were comparable with the measurements collected from a background monitoring point. These results indicate that the containment structure for the buried radiological material remains intact and that the surrounding soil does not appear to have been impacted by this material.

As part of the LTM Work Plan, an annual inspection at site ST-18 included a detailed visual observation of the concrete cap. The inspection consisted of walking several transects across the concrete cap area and noting visual cracks, joints, former penetrations, and other features of interest (such as previous repairs) that may affect the integrity of the cap. The 2009 annual inspection indicated that the cap has been maintained per the ROD, is still functioning as intended, and remains an effective barrier to surface water infiltration.

2008: New groundwater monitor wells were installed in April to replace submerged wells. Long-term monitoring of 10 Installation Restoration Program (IRP) sites continued, including the fire training area, bulk fuels storage, wastewater treatment annex landfill, oil/water separator canal and former liquid waste storage facility.

2007: The second FYR was completed in June.

1997 – 2002: A final potential source of contamination inspection was completed in August 1997. Also, the U.S. Environmental Protection Agency (EPA) and ADEQ conducted a final site inspection in April 2000 and determined that the USAF constructed the remedy in accordance with the requirements in the RODs for the entire site and the remedial action work plans. EPA concurred on the final close-out report on April 26, 2001. An IC plan dated Dec. 15, 2001, was developed by the USAF, and EPA concurred on the plan on Jan. 8, 2002. In 2002, the first FYR report was completed, and EPA concurred on the review in January. The site was officially deleted from the National Priorities List (NPL) on April 22; however, there are ICs that serve to maintain the current site conditions and control the risks to human health by prohibiting residential development.

1990: The site was placed on the EPA’s NPL (a.k.a. Superfund) on August 30. The primary use of the site was to provide advanced flight training to fighter pilots. Discharges and waste disposal practices resulted in soil contamination. The site participated in the IRP, a specially funded program established by the Department of Defense (DOD) in 1978 to identify, investigate and control the migration of hazardous contaminants at military and other DOD facilities. A Federal Facilities Agreement to conduct the site cleanup plan was signed in September.

1983: In November, eight water supply wells on the base were sampled as part of IRP. Analysis indicated that two of the wells had low levels of 1,2-dichloroethane (1,2-DCA) and trans-1,2-dichloroethene (1,2-DCE). Soil near one of the wells contained 1,2-DCA. An estimated 10,400 people obtain drinking water from base and private wells within three miles of hazardous substances on the base.

1951 – 1973: The Perimeter Road Petroleum, Oil, and Lubricants (POL) Waste Application site (site No. 4) was used during approximately 1951-70. POL wastes were spread on the dirt road around the runway at the western portion of the base. The majority of the wastes consisted of contaminated JP-4 fuel, with some diesel fuel, waste engine oils, and waste solvents. Among the substances that may have been included were methyl ethyl ketone (MEK), trichloroethane (TCA), trichloroethene (TCE), toluene, cresylic acid, o-dichlorobenzene, phenolic paint strippers, acetone, and paint residues and thinners.

The POL Waste Disposal Trench site (site No. 5) was used during about 1970 – 72. POL wastes were disposed of in numerous trenches approximately 1.5 feet deep and in a shallow lagoon at the northeast corner of the site.

The South Fire Department Training Area (site No. 6) was used during 1941 – 46, and again during approximately 1951 – 63. POL wastes were poured onto old aircraft or simulated aircraft in a cleared, bermed area and then set on fire.

The North Fire Department Training Area (site No. 7) was used during approximately 1963 – 73. The disposal method was similar to site No. 6.

Thirty-two areas of the base were subject to further investigation: two fire training areas; a waste oil and fuels underground storage tank area; three waste oil disposal trench areas; three surface drainage canals receiving oily wastes; a sewage treatment plant effluent canal; the site of an abandoned Defense Reutilization and Marking Office; thirteen land disposal sites (one of which contains a radiological disposal area); an old incinerator site; a former outside transformer storage site; two leaking underground storage tank sites; an abandoned surface impoundment; an ammunition storage area; a skeet range; and the base production wells.

1941 – 1951: Industrial-type operations started in 1941 and were comparatively small until 1946. After a period of deactivation, the base resumed operations in 1951. During the 1950s, larger quantities of wastes were generated by the expanded maintenance required for the new jet aircraft assigned to the base. At the Waste Treatment Annex (site No. 2), a small quantity of low-level radioactive electron tubes, believed to be encased in concrete, was buried in a pit 12 feet deep in 1956.