Pacific Southwest, Region 9: Superfund
Serving Arizona, California, Hawaii, Nevada, the Pacific Islands, and Tribal Nations
Phoenix-Goodyear Airport Area
EPA #: AZD980695902
Congressional District: 04
Other Names: Phoenix-Goodyear Airport Area Litchfield Airport Industrial Area Phoenix-Litchfield Airport Area
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Description and History
NPL Listing History
NPL Status: Final
Proposed Date: 12/30/82
Final Date: 09/08/83
The Phoenix-Goodyear Airport (PGA) Superfund site is geographically situated approximately 17 miles due west of Phoenix, in the western part of the Salt River Valley in Central Arizona. During EPA’s Remedial Investigation of the site, two distinct contaminant source areas were identified: one centered under the Unidynamics Phoenix Incorporated (UPI) facility north of Yuma Road and the other associated with Goodyear Aerospace/Loral Facility adjacent to the Litchfield Airport (presently known as the Phoenix-Goodyear Airport). Thus, the PGA National Priorities List (NPL, commonly called Superfund) Site now consists of two distinct areas: 1) the former UPI facility, referred to as PGA-North, and 2) the former Goodyear Aerospace/Loral facility, referred to as PGA-South. PGA–North is bisected by US interstate 10 and PGA–South is bounded on the southern side by Highway 85. The two study areas cover a total of 35 square miles.
Except for the airport, which is owned by the city of Phoenix, the PGA Site lies almost entirely within the city of Goodyear, Arizona. The City of Avondale occupies about 2 square miles along the eastern border of the site. Current land uses on and near the site include agriculture, residential, and commercial development. Land use trends predict a future increase in residential and commercial development with a corresponding decrease in agricultural usage. The general area within a radius of about 5 miles has a combined population of about 75,000 people including residential development west of the airport.
Site History: PGA-South: The United States Navy established the Litchfield Naval Air Facility (NAF) in Goodyear, Arizona in 1943 as an Auxiliary Acceptance Unit. The Unit accepted modified aircraft for the Navy from the Goodyear Aircraft plant located adjacent to the airport.
From 1946-1968, the airport’s primary purpose was the preservation and activation of military aircraft. The preservation of aircraft involved treating the engines to repel dust, rust, and moisture and then spraying the aircraft with a protective latex coating that contained a ketone solvent. Stripping off the protective coating required the removal of the latex with a solvent and returning the parts to working order. This process was repeated every six months and the effluent [waste material discharged into the environment] from the process entered drains which discharged directly into the main airport drainage ditch. Up to as many as 2,000 aircraft per year were preserved at the Litchfield NAF. In addition to the preserving and stripping chemicals which were discharged into the drainage channel, it is assumed that other liquid substances generated as a part of routine aircraft maintenance were also discharged. A sample taken of the drainage channel discharge on April 20, 1951 had the following physical characteristics: “...30% dark colored, oily, floating liquid, approximately 5% granular settleable solids and the balance was fairly clear, chrome colored liquid...From the color of the oil free sample, there is no doubt some chromate present.” (Letter dated May 24, 1951 from Process Engineers Inc. To Public Works Office, 11th Naval District, San Diego, CA).
In 1952, the Navy upgraded its on-site domestic sewage treatment tank to accommodate secondary treatment, and industrial wastewater from the drainage ditch was diverted to the plant for treatment using a gravity flotation process. Oil and other floatables were skimmed off the top and spread over the airport grounds as weed control. Solvents, such as trichloroethylene (TCE), which are heavier than water, would not be removed in such a gravity separation tank, would remain in the wastewater, and be subsequently discharged back into the drainage channel.
In 1968, the Navy transferred ownership of the property to the City of Phoenix, and the airport became the Phoenix-Litchfield Municipal Airport. Goodyear Aerospace Corporation, Arizona Division (GAC) began operations in 1942, at which time it was owned by the United States Government and operated by Goodyear Aircraft Corporation. The plant was closed from 1946-1949, when it was reopened under Goodyear Aircraft Corporation. During the 1940s, aircraft from the Naval Air Facility were brought into the hangars of the plant for machining of parts and parts installation. This included cleaning engines with solvents prior to maintenance work.
More recently, major operations at the facility have included the manufacture of electronics equipment, transparent products such as windshields, structural equipment such as the MX missile transporter, and aluminum shelters. The major waste streams generated at Goodyear Aerospace have been: solvents (trichloroethylene, trichloroethane, acetone, etc.); chromate sludge from chrome plating operations; acids (sulfuric, hydrochloric, chromic, acetic, and hydrofluoric); process waste waters (cooling waters, boiler blowdowns, etc.); and domestic sewage. Three on-site sludge ponds were used for waste disposal.
Site History: PGA-North: Unidynamics Phoenix, Inc. was established in 1963 as a research, development, and manufacturing plant for defense and aerospace equipment. Typical products included: separation and recovery systems (safing, arming, and fusing devices), destruct systems (pyrotechnic devices), and munitions. The primary operations at the plant included manufacturing rocket propellant, processing and blending powder, assembling ordinance, machining, testing explosives, ballistics and related functions. Contaminants of concern from operations on-site include perchlorate (the primary chemical ingredient of solid rocket propellant) and VOCs such as TCE which were associated with waste disposal at the UPI facility. Eleven dry wells and two unlined oxidation ponds were used at the facility for direct on-site disposal of most wastes up until 1980. Prior to 1978, all waste solvents were disposed of on-site in four dry wells outside and to the west of the manufacturing facility. The two oxidation ponds were used for on-site disposal of washing and cooling water with traces of process chemicals, oils, and powder. Wastes generated by the facility have included: trichloroethylene, toluene, acetone, methanol, cobalt nitrate, ammonium carbonate, perchloric acid, and fuel oil.
Contaminants and Risks
- Soil and Sludges
- Environmentally Sensitive Area
In 1981, the Arizona Department of Health Services (ADHS) discovered that groundwater in the PGA area was contaminated with solvents and chromium. Additional sampling of wells in 1982 and 1983 by ADHS and EPA revealed 18 wells contaminated with trichloroethylene (TCE). Six of these wells exceeded ADHS’ drinking water action level of 5.0 parts per billion (ppb). Three of these well were used for drinking water. As a result, the EPA added PGA (originally listed as the “Litchfield Airport Area Superfund Site”) to the National Priorities List (NPL) on September 8, 1983 (see Federal Register, Vol. 48, No. 175, p. 40671).
In 1984, EPA began a Remedial Investigation of the then Litchfield Airport Area to characterize the site, investigate the extent of the contamination, and identify the potential sources. Drinking water supplies, industrial water supplies, and irrigation water come solely from groundwater that is pumped from the alluvial deposits of the western Salt River Valley underlying the entire area.
Contaminants of Concern found in the groundwater at the PGA site include: TCE; chromium; perchloroethylene (PCE); 1,1-Dichloroethylene (1,1 DCE); chloroform; and carbon tetrachloride. Contaminated groundwater is actively being treated and is not being used as drinking water; therefore it poses no current risk to residents in the surrounding area. Several organic and inorganic compounds were also found in the soils at the site which exceeded AHDS health-based cleanup levels, including: chromium; cadmium; aluminum; copper; TCE; and PCE. In addition, concentrations of methyl ethyl ketone (MEK) and acetone were detected as high as 659 mg/kg and 888 mg/kg, respectively, in the northern area of the site. Carbon tetrachloride, benzene, TCE, and PCE also exceeded the AHDS guidelines in air samples. Current levels of contamination in air and soil on the site do not pose a risk to construction workers, commercial/industrial workers, or trespassers.
Most of the contaminants identified at PGA can be classified as organic compounds. Several of these compounds (e.g. carbon tetrachloride, chloroform, 1,1,1-trichloroethane, PCE, and TCE) may produce liver injury at high doses. Carbon tetrachloride and chloroform have more serious effects on the liver than TCE and PCE. Carbon tetrachloride, chloroform, PCE, and TCE have been classified by the EPA as probable human carcinogens via ingestion. Exposures to these compounds at high doses through inhalation may result in central nervous system depression, including anesthesia. Other effects may include irritation of the mucous membranes of the nose and throat and irritation to the eyes.
Inorganic compounds, including metals, were also found at the PGA site. Some of the inorganic compounds detected at the site, such as chromium, are much more toxic than others. Chromium has been identified in some water samples taken from the site in both the trivalent and hexavalent states. Chromium compounds in the trivalent (+3) state are of a low order of toxicity. Hexavalent chromium may cause liver and kidney damage, internal bleeding, and respiratory disorders and has been designated as a human carcinogen. At PGA-South, chromium in the groundwater is approximately 80% hexavalent and 20% trivalent.
There is no current health risk at the site because contaminated groundwater is not being used as a drinking water source. Also, there is no current health risk from exposure to soil or soil vapor as levels of contaminants are low in these media.
Environmental Risks: Within the PGA site, there are no unique habitats nor any threatened or endangered species. Native vegetation is sparse. However, located immediately south of the site, the lower Gila River represents the most important riparian habitat in southwestern Arizona. Species that inhabit or migrate through the area include four federally listed or endangered species. These are: the Brown Pelican (Pelecanus occidentalis), the Yuma Clapper Rail (Rallus longirostris yumanensis), the Peregrine Falcon (Falco peregrinus), and the Bald Eagle (Haliaeetus leucocephalus). The PGA area, particularly near the Gila River, supports viable hunting populations of mourning dove, Gambel’s quail, and various waterfowl. The area is especially popular for dove hunting and is known to support one of the largest breeding dove colonies in the Southwest.
In August 2014, a burrowing owl survey was conducted at PGAS prior to installing additional remedy pipeline. A total of eight active burrows were discovered and pipeline was moved accordingly to prevent impacts to owls.
Who is Involved
This site is being addressed primarily through potentially responsible parties' actions with federal and state oversight.
Investigation and Cleanup Activities
The Record of Decision (ROD) for the final remedy at the PGA site was signed by the EPA Regional Administrator on September 26, 1989. To date, five 'Explanation of Significant Differences' (ESDs) have been executed to modify or clarify the final remedy. Two Consent Decrees prescribing tasks to complete the remedy at the southern portion of the Site were signed by EPA and the Goodyear Tire & Rubber Co. in May 1988 and May 1991. A Consent Decree for 15 tasks designed to complete the remedy at the northern portion of the Site was signed by EPA and Crane Co. in June of 2006. EPA proposed an improvement to the remedy for the northern portion of the site in February 2014. Work with in-situ treatment of contamination in the Main Dry Wells Source Area began in 2015 and is ongoing.
Initial Actions: In the southern portion of the site, the former chromium sludge drying bed has been cleaned up by using on-site solidification technology. Construction of the remedy was completed in early 1993. Solidifying the sludge bed has prevented migration of chromium into the groundwater and chromium dust particles into the air.
For the southern part of the site, the remedy consists of extraction and treatment of contaminated Subunit A groundwater and Subunit B/C groundwater, and soil vapor extraction for contaminated soils. The Subunit A groundwater remedial action requires a pump and treat system using air stripping to remove volatile organic compounds (VOCs) from the groundwater. The Subunit B/C groundwater remedial action requires two separate pump and treat systems using liquid granular activated carbon to remove VOCs from the groundwater. With respect to VOC soil contamination at the southern portion of the PGA site, the ROD selected a soil vapor extraction (SVE) system with emission controls. ESD #3 added two additional technologies. Air sparging is used in conjunction with the SVE system to enhance cleanup of the Subunit A groundwater. This results in an estimated cost savings of approximately $900 per pound of VOCs removed. Advanced Affinity Chromatography uses a treated resin to remove chromium from the Subunit A groundwater at a well with elevated levels of chromium.
The remedial action selected for the northern half (PGAN) of the site is similar to that chosen for the south (PGAS) and includes a Subunit A groundwater remedy, a Subunit C groundwater remedy, and a soil remedy. The groundwater remedy consists of a network of fifteen groundwater extraction wells (11 in Subunit A, 1 in Subunit B, 3 in Subunit C) and fifteen groundwater injection wells designed to contain the plume and restore the contaminated aquifer. The extracted water is treated at five ground water treatment facilities. One of the five facilities uses air stripping to remove VOCs and the treated water is either re-injected into Subunit A at the former Unidynamics facility or used for irrigation. The other four facilities utilize Liquid-phase Granulated Activated Carbon (GAC) to remove the VOCs and the treated water is either re-injected, discharged to the Roosevelt Irrigation District (RID) canal for use as irrigation water, utilized in construction to suppress dust or is delivered to one of the local golf courses for turf irrigation. In 2008, two additional systems were added for treatment of groundwater in the Northeast Section of the plume. This water is being used for irrigation, or being re-injected back into the aquifer. In 2011, an additional treatment system was added for treatment of groundwater in the Northwest Section of the plume and that water is being re-injected back into the aquifer.
The soil remedy consists of a SVE system with air emission controls in the source area at Unidynamics. The ROD identifies the source area, or “target area,” as that area where VOCs were detected in soil samples and the area where soil gas samples exhibited VOCs greater than 1 microgram per liter. The ROD provides that this area may be expanded or reduced, as necessary, to include removal of 99 percent of the contaminants. In addition, the ROD states that excavation and treatment may be required to remove residual contamination where soil vapor extraction is not effective. The SVE treatment system for the PGA-North area was in operation from 1994-October 1998 on a periodic basis. In October 1998, the SVE system was turned off to evaluate the need for continued soil vapor extraction at PGA North. The SVE system was restarted in 2004 and has removed more than 2100 pounds of TCE through June 2016.
Following issuance of a final ROD in 1989, EPA, the state of Arizona, and Goodyear Tire signed a consent decree for remediation of PGA-South in 1991. Goodyear Tire, as the leading potentially responsible party (PRP), has complied with all required cleanup actions including: (1) cleanup of metal contaminated soils, (2) cleanup of VOC contaminated soils, and (3) cleanup of contaminated groundwater in both upper and lower portions of the aquifer. Action (1) is complete and actions (2) and (3) are in the Operations and maintenance (O&M) phase. Soil Vapor Extraction has been very successful for the cleanup of VOC contaminated soils and has removed approximately 2,524 pounds of VOCs. Goodyear Tire asked EPA and the State of Arizona to approve the closure of the third and final SVE remedy in 2003. This became the first successful total closeout of VOC contaminated soil cleanup at an Arizona Superfund site. In 2014 - 2016, optimization of the groundwater treatment system at PGAS is underway.
Approximately 4,000 cubic yards of chromium contaminated soils have been removed to date.
With 3 groundwater remediation systems operating, EPA has been a high level of success in containing the TCE plume to prevent off-property migration. Approximately 2.2 billion gallons have been pumped from the contaminated aquifer, removing 3,300 pounds of VOCs. To date, an estimated 75% of the total VOC mass in the groundwater has been removed. In addition, the treatment system has removed approximately 2.8 pounds of chromium from the Subunit A groundwater.
Crane Co. is conducting the cleanup activities at PGA-North under the authority of a Consent Decree which was signed in June 2006. The on-site groundwater treatment facility and soil vapor extraction system have removed over 57,000 pounds of TCE from the soil (10,000) and groundwater (47,000) on site. The new treatment facilities, which Crane Co. voluntarily constructed at the northeastern and northwestern extents of the plume, are now removing approximately 1,500 pounds more of TCE per year.
EPA recognizes the importance of protecting water resources, especially in the Southwest, and has evaluated seven alternatives for speeding up the current remedy in PGA-North in the Focused Feasibility Study, completed in 2013. EPA signed a Record of Decision Amendment in September 2014 to treat Source Area at PGA-North.
Cleanup Results to Date
While construction has been completed at PGA-South, the construction completion date for PGA-North is planned for September 2020.
Potentially Responsible Parties
Potentially responsible parties (PRPs) refers to companies that are potentially responsible for generating, transporting, or disposing of the hazardous waste found at the site.
The PRP for PGA-North is Crane Co., and the PRP for PGA-South is Goodyear Tire and Rubber Co.
Documents and Reports
Public Meetings: Community Advisory Group (CAG) meetings are held quarterly. Contact Carlin Hafiz, EPA, below, for meeting dates and schedules.
Public Information Repositories
The public information repositories for the site are at the following locations:
UPDATED LOCATION 2014!
Goodyear Branch Library
14455 West Van Buren Road, Ste C-101
Goodyear, AZ 85338
EPA Site Manager
Mail Code SFD
75 Hawthorne Street
San Francisco, CA 94105
EPA Community Involvement Coordinator
Mail Code SFD
75 Hawthorne Street
San Francisco, CA 94105
EPA Public Information Center
1110 W Washington St
Phoenix, AZ 85007
100 First Stamford Place
Stamford, CT 06902
Citzens Advisory Group (CAG) Co-Chair
Citzens Advisory Group (CAG) Member
After Hours (Emergency Response)