NPL Site Narrative for Midway Landfill
Federal Register Notice: June 10, 1986
Conditions at proposal (October 15, 1984): Midway Landfill covers 60 acres in Kent, King County, Washington. From January 1966 to October 1983, this landfill, which is on privately owned land, was operated by the City of Seattle. It was the repository of nonputrescible wastes and some industrial sludges from the Seattle area. The landfill is unlined and is in an old gravel quarry.
Data collected by the Seattle-King County Health Department and the State from on-site monitoring wells indicate that an aquifer is contaminated with lead, toluene, xylene, arsenic, and other compounds. More than 10,000 draw their drinking water from the aquifer within 3 miles of the site.
The City of Seattle is preparing a plan for closing the landfill in accordance with all solid waste disposal requirements of the Resource Conservation and Recovery Act. The plan calls for drilling several monitoring wells to define the direction of ground water flow relative to several major municipal wells nearby. Soil samples will also be taken.
Status (June 10, 1986): The City of Seattle has installed the new monitoring wells. Anomalies found during the drilling indicate a need for some additional wells.
Under a cooperative agreement with EPA, the Washington Department of Ecology is reviewing the city's work. The State is directing a remedial investigation/feasibility study to determine the type and extent of contamination at the site and identify alternatives for remedial action.
Combustible gas has been found in the soils under residential and commercial areas adjacent to the site, requiring temporary relocation of 11 families. In January 1986, the city began operating a gas extraction system on-site in an effort to control off-site migration of methane. The city and State are developing an additional off-site extraction well system to remove methane trapped in the ground off-site. A special gas sampling program was initiated to deal with the gas problem.
For more information about the hazardous substances identified in this narrative summary, including general information regarding the effects of exposure to these substances on human health, please see the Agency for Toxic Substances and Disease Registry (ATSDR) ToxFAQs. ATSDR ToxFAQs can be found on the Internet at ATSDR - ToxFAQs (http://www.atsdr.cdc.gov/toxfaqs/index.asp) or by telephone at 1-888-42-ATSDR or 1-888-422-8737.