EPA ID# WAD980511778
EPA Region 10
Spokane County

5th Congressional District

Other Names: City of Spokane Indian Trails Landfill, North Landfill
Last Update: August, 2012

Hide details for Site DescriptionSite Description

The Northside Landfill is located on a 345-acre parcel of land in northwestern Spokane, Washington. The site was established as a city landfill in 1931 and was the largest refuse disposal operation in Spokane County. The site was used for open burning until the mid-1950s, when open burning was replaced with shallow excavation and fill operations. In the 1960s, the process of covering refuse-filled trenches and canyons with soil was used. In the mid-1970s, an area fill technique was started using 20-foot lifts (20 feet thick layers) on previously buried refuse. The existing landfill stopped receiving refuse in December, 1991. More recently, a new waste disposal cell, meeting all new State requirements for landfills, was constructed. This action will allow a 15-acre parcel on-site to continue operations as a small special municipal landfill in the future. It is anticipated that Northside will be used as a demolition waste and incinerator by-pass disposal site. Volatile organic compounds (VOCs) have filtered into the aquifer beneath the site. The aquifer is the sole source of drinking water for the city of Spokane. Approximately 65 residents live in the area of the groundwater plume.

Site Responsibility: This site is being addressed through federal, state, potentially responsible parties and municipal actions.

NPL Listing HistoryDates
Proposed Date:10/15/1984
Removed Date:
Withdrawal Date:
Final Date:06/10/1986
Deleted Date:

Hide details for Threats and ContaminantsThreats and Contaminants

Media Affected: Groundwater, Soil & Sludges
The RI/FS indicated that solvents were present in the groundwater downgradient of the landfill. Several nearby domestic water wells were contaminated with organic solvents including tetrachloroethylene (PCE). On-site sludge contains trichloroethylene (TCE) and PCE. Potential health risks exist for individuals who ingest or come into direct contact with contaminated groundwater or sludge.

Hide details for Cleanup ProgressCleanup Progress

Early Actions: In 1983, the city of Spokane extended municipal water service to homes that had contaminated wells and later to the entire area downgradient of the landfill. All residences within the contaminant plume area have been provided with alternate water supplies. The city is regularly monitoring on-site wells and a number of off-site wells and has determined the location and direction of the flow of the plume.

Landfill Remediation: In 1989, EPA selected a remedy for the landfill that includes the following: closure of the old landfill units as soon as possible; installation of a cap after closure to reduce infiltration and contaminant loading to groundwater; interim pumping and treatment of the groundwater to reduce the contaminant migration; groundwater monitoring; installation of a gas collection system to control landfill gas; and institutional controls to protect the landfill, cap, and monitoring wells from unauthorized access. The City of Spokane, under a CERCLA Consent Decree (CD), designed and built the remedy, completing construction in 1993. Local residents continue to use the alternate water supply (Spokane's municipal water service).

Long-Term Actions: As of 2012, EPA has completed four five-year reviews since the ROD to verify that the cleanup continues to be protective of human health and the environment. Landfill cap monitoring and maintenance have ensured the remedy's effectiveness in preventing direct contact and control of surface water infiltration. Groundwater outside the landfill boundary now meets federal drinking water standards. Controls on access, land use and well construction at and near the landfill are in place pursuant to zoning, state law regarding municipal landfills (Washington's Minimum Functional Standards), and permitting processes. The City conducts ongoing landfill operations in an area outside the capped landfill under a state permit.

In 2007, with extraction and treatment of groundwater ongoing, the groundwater compliance wells, extraction well, and off-site monitoring wells had not exceeded the groundwater cleanup levels for over two years. In 2008, however, periodic low exceedances of these levels were observed in quarterly monitoring. The ROD states that, following two years of meeting groundwater cleanup levels, groundwater extraction and treatment operations shall be suspended for a year of monitoring to evaluate whether contaminant concentrations continue to meet the cleanup levels without treatment. EPA and the Washington Department of Ecology are working with the City to assess proposals on an appropriate operating schedule for groundwater extraction and treatment.

The 2007 five-year review stated that the remedy is currently protective but recommended a detailed review of the institutional controls. The review was needed to ensure that in the future, when the City no longer operates active landfill cells, the restrictions on site uses, well drilling, and access will be continued as necessary. The review also recommends that an Explanation of Significant Differences (ESD) be published to document minor changes in the remedy, as extracted groundwater is no longer treated at a publicly owned treatment works but is aerated on site. The ESD will also clarify the ROD cleanup levels and points of compliance. The review, completed in June 2008, included a title search which found that the City had not implemented the institutional controls required under the CERCLA CD (as well as the judicial order which terminated the CD), which included deed restrictions on the landfill parcels.

In September 2009, EPA issued an Explanation of Significant Differences to document the change to onsite treatment (by aeration) of groundwater discharge and to ensure that cleanup levels and points of compliance were clear following the City's purchase of land for infiltration of surface water runoff. The City, State of Washington, and EPA signed a covenant for institutional controls under the Uniform Environmental Covenants Act, to satisfy the institutional controls requirements in the ROD. The covenant was recorded in June 2011.

The fourth Five Year Review indicates that the remedy continues to protect human health and the environment. After the groundwater cleanup levels were exceeded in 2008, subsequent monitoring showed continuous achievement of these drinking water standards. The Five Year Review recommends that the City document completion of repairs to the extraction well and landfill cover system in 2012. The City may then request approval for suspending operations of the pump and treat system for a period of confirmation monitoring.

Hide details for Regional ContactsRegional Contacts

PHONE NUMBER:206-553-1215
Information pertaining to this site is housed at the following location(s):
Spokane Public Library (Administrative Record)
906 West Main
Spokane, WA 99201

City of Spokane (Selected Documents)
Engineering Services Division
West 808 Spokane Falls Boulevard, Room 318
Spokane, WA 99201

EPA Region 10 Superfund Records Center (Administrative Record)
1200 Sixth Avenue, ECL-076
Seattle, WA 98101