hassayampa landfill


The Hassayampa Landfill Superfund Site (Site) is geographically situated approximately forty miles west of Phoenix and approximately three miles north of Arlington, in Maricopa County, Arizona. The approximately 10-acre Superfund Site was used for disposal of hazardous wastes for an eighteen month period between 1979 and 1980. This former hazardous waste disposal area (Site) is located in the northeast section of closed sanitary landfill that was operated by Maricopa County. The entire property is seventy-seven acres, of which forty-seven acres were used for the disposal of municipal and domestic solid waste. The Site, the 10-acre hazardous waste disposal area, is part of the 47 acres used for disposal of municipal waste The Site lies within the drainage area of the ephemeral Hassayampa River, which is located half a mile east of the Site, but outside of the 100-year floodplain. The Site is located in an alluvial-filled basin, which has been influenced by the nearby river and the Arlington Mesa. A regional aquifer consisting of basin-fill deposits underlies the Site and comprises the principal source of groundwater to wells in the area. The groundwater flow direction is general to the south-southwest. Approximately 350 people draw drinking water from private wells, and 2,800 acres of farmland are irrigated by wells within three miles of the site. The nearest downgradient residential well is about 1,000 yards south of the hazardous waste area. Surrounding land use includes mostly desert (undeveloped) land with some cultivation (approximately one-sixth of the total surrounding land use). Vegetation is sparse and includes creosote and salt bushes. There are no residents living in the immediate vicinity of the Site, although there were several landfill employees who worked in the non-hazardous portion of the landfill until it was closed in 1997. Future residential land use of the landfill property is considered unlikely. There is some increase of residential development near the Site in recent years. Maricopa County began operating Hassayampa as a municipal landfill beginning in 1961. During the period of April 20, 1979 to October 28, 1980, hazardous wastes were disposed in unlined pits in a 10 acre area in the northeast section of the landfill. This disposal occurred under a manifest program operated by the Arizona Department of Health Services (ADHS) in response to an “extreme emergency” that resulted from an ADHS ban on the disposal of industrial waste at City of Phoenix landfills. When landfills along the Salt River were closed to industrial waste disposal due to flooding, industrial waste was transported and disposed of at the Hassayampa Landfill site. ADHS used a manifest system to screen and track industrial waste deliveries to the landfill during this period. Under this program, a wide range of hazardous wastes were approved by ADHS for disposal at the Hassayampa Landfill, including up to 3.28 million gallons of liquid wastes and 4,150 tons of solid wastes. Manifests were used to document the volume and type of wastes and the names of the generators and transporters. The landfill pits were subsequently covered with native soil and restored to grade at the end of the eighteen month period. Disposal to the municipal landfill ceased in June, 1997.

Hazardous Ranking Score

43 / 100

A score of 28.5 or higher qualifies a site for the Superfund National Priority List.

Regional Contact

Region 9
Phone: (415) 947-4251

Contact Region



Site Inspection
Preliminary Assessment
Final Listing On NPL

Contaminants & Health Effects

      Endocrine Disrupter
      Reproductive Toxin
      Persistent, bioaccumulative and toxic


        African American
        American Indian and Alaska Native
        Native Hawaiian


        People living
        within a 1 mile radius


        Average Income


        Occupied homes

        Potentially Responsible Parties

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