1942 - 1974

PGA served as the Litchfield Park Naval Air Facility since 1942.  Goodyear Tire and Rubber Company began operating Goodyear Aerospace at the airport, modifying and repairing aircraft, which were then transferred to the adjoining Navel Air Facility from 1940 to 1945. In 1946, the Naval Air Facility was placed in modified maintenance status. Its primary function became the preservation and activation of military aircraft. 

In 1968, the Navy transferred ownership of the property to the City of Phoenix. In 1974, Goodyear Aerospace discontinued using TCE at PGAS.

1981 - 1984

ADHS discovered groundwater contamination in 1981. EPA added the site to the NPL on September 8, 1983. In 1984, TEPA began a remedial investigation (RI) of the Litchfield Airport Area (presently known as the Phoenix-Goodyear Airport) to characterize the site, discover the extent of the contamination, and identify possible sources.  From this study, the site was divided at Yuma Road into a north and a south portion.

1989 - 1991

The RI/feasibility study (FS) for the site was completed in June 1989, and a comprehensive final remedy ROD was signed in September for PGAN and PGAS. A Consent Decree (CD) for the final remedy was lodged on May 7, 1991 and entered in November, with EPA, the State, Goodyear Tire and Rubber Company, and Loral Defense Systems as signatories. This document binds Goodyear Tire and Rubber Company to remediate the Subunit B/C aquifer and contaminated soils.

1992

Goodyear Tire and Rubber Company conducted a removal action of metal contaminated soils located at the sludge drying beds. The soils containing chromium and cadmium above the Health Based Guideline Levels were stabilized, thereby eliminating the risk of exposure by ingestion and inhalation and preventing further migration to groundwater.

1993

Tetrachloroethene (PCE) was detected in PGAS Subunit A groundwater wells coming from the Western Avenue PCE Water Quality Assurance Revolving Fund (WQARF) (dry cleaning) site due east and upgradient of the PGAS plume.

1994 - 1998

There are two plumes within Subunit C associated with the site, caused by conduit wells, which were promptly abandoned. Groundwater extraction and treatment of these two plumes began in 1994 using granular activated carbon. In April 1998, ADEQ approved the closure and decommissioning of the SVE system. The Vadose Zone Leaching Model was used to determine that the residual threat to the groundwater was below the maximum contaminant level. The Goodyear Tire and Rubber Company has thereby satisfied the requirements under the 1991 CD for closure of soils.

2004 - 2007

An extraction well (E-102) for the northern portion (head) of the northern Subunit C plume was installed and up and running in November 2004. The five year review (FYR) report was prepared and finalized by the EPA in September 2005. EPA identified several issues to be addressed by the Potential Responsible Party (PRP). Issues brought up during the FYR were addressed and work plans for a new extraction well (E-18) were approved in 2006. Due to age, Goodyear Tire and Rubber Company conducted maintenance on many components of the treatment systems in 2007. Groundwater monitoring and operation and maintenance (O&M) activities of the groundwater treatment systems continued.

2008

The O&M Manuals were updated and metals sampling rounds were conducted. Groundwater monitoring and O&M activities of the groundwater treatment systems continued. ADEQ and EPA met with the Goodyear Tire and Rubber Company to have groundwater wells installed to further delineate the Subunit C plume north of Yuma Road.

2009

Goodyear Tire and Rubber Company recommended pulsed pumping to overcome hydraulic stagnation and to address the residual contaminant mass in Southern Subunit C groundwater. A Work plan submitted to install two additional wells (GMW-21UC and GMW-22UC) to monitor TCE concentration in production well GAC-04 was submitted.

2010

Groundwater monitoring continued to track contamination at PGAS. Goodyear Tire and Rubber Company completed a pulsed pumping evaluation of the Southern Subunit C plume. Well rehabilitation was completed on three Subunit A wells (E-12, E-7, and NE-5) and on Subunit C wells I-201 and I-203. Two new Subunit C monitoring wells were installed in an effort to understand contamination in wells GAC-04 GMW 21C and 22C.

ADEQ and EPA completed the FYR for PGAS. A protectiveness determination of the remedy was not made in the report, but was deferred until further information is obtained. While the TCE plume at PGAS has been mostly delineated with COC concentrations in the plume being stable or decreasing over the last five years, the northwestern edge of the northern plume is not completely defined. Further information will need to be obtained by conducting a groundwater investigation of northern TCE plume in Subunit C. Several issues that affect long term protectiveness have also been identified: The source and extent of the TCE contamination in and around GAC-04 has not been determined and the continued occurrence of elevated chromium in the northern Subunit A plume has not been fully understood.

2011

EPA took over as lead Agency for PGAS in the fall (EPA was already the lead Agency for PGAN), which helped EPA initiate/manage the study of the area between the sites (ABS - the area between PGAN and PGAS). The ABS study was an action item from the FYR. ADEQ and EPA continued to meet with the Goodyear Tire and Rubber Company to have groundwater wells installed to further delineate the Subunit C plume north of Yuma Road.

2012

Several Subunit A monitoring wells were abandoned/replaced mostly due to a drop in groundwater elevation; making it difficult or impossible to acquire a proper groundwater sample which is needed to meet the needs of the Comprehensive Groundwater Monitoring Plan (CGMP). Goodyear Tire and Rubber Company conducted maintenance on many components of the Subunit A treatment systems. ADEQ and EPA continued to meet with the Goodyear Tire and Rubber Company to have groundwater wells installed to further delineate the Subunit C plume north of Yuma Road. GAC-04 Supply Well Investigation was completed and the final determination was to abandon the well. The well was abandoned in late fall.

2013

Well abandonment and well replacement activities continued for Subunit A along with enhancements/improvements on the treatment systems. An extraction well (E-07R) had a new pump installed. New Subunit C monitoring wells were drilled to further delineate the Northern Subunit C plume.

2014

Over 5,674 pounds of cumulative TCE mass has been removed from start up of the Subunit A treatment system in 1990 through the first half of 2014. In 2014 a new Subunit C extraction well and piping was completed in order to remove mass and contain the plume. Three new extraction wells are planned for 2014 for the Subunit A plume in order to better optimize the system and increase removal of contaminants.

2015

Released: Third Five Year Review Report
Continued:  Groundwater monitoring; Plume capture and containment; Plume treatment system (includes extraction, remediation, and beneficial use components)

2016

Released: Explanation of Significant Differences related to select stabilized fill not requiring institutional controls.
Expanded:  Groundwater well network (includes monitoring, extraction, and injection); Plume treatment system
Continued:  Groundwater monitoring; Plume capture and containment; Plume treatment system

2017

Released:  Vapor intrusion investigation framework
Expanded:  Groundwater well network (includes monitoring, extraction, and injection); Plume treatment system
Continued:  Groundwater monitoring; Plume capture and containment; Plume treatment system