Superfund Information Systems: Site Profile

Superfund Site:



On this page:

About the Superfund Redevelopment Initiative

This nationally coordinated effort provides EPA and its partners with a process to return Superfund sites to productive use. Learn more at Superfund Redevelopment Initiative.

Top of Page

Redevelopment at the Site

The 60-acre Midway Landfill Superfund site is located in King County, Washington, between U.S. Interstate 5 (I-5) and U.S. Highway 99. The former gravel quarry operated as a municipal solid waste landfill from 1966 to 1983. Local officials created Midway Landfill primarily to accept demolition materials, wood waste and other slowly decomposing materials. However, operators also put other industrial wastes in the landfill. In 1983, the operators covered the landfill with silt and fine sands. In 1985, investigations identified combustible gas in structures around the landfill and contaminated groundwater beyond the landfill boundary. EPA added the site to the Superfund program's National Priorities List (NPL) in 1986. In 1992, the City of Seattle constructed a final cap over the site, refined landfill gas control, and installed a stormwater and drainage control system. These measures continue to function as planned. The Washington Department of Transportation is using a portion of the site located in a right of way for an I-5 road-widening project. The other portion of the site remains a closed landfill and is unused open space.

Top of Page

Economic Activity at the Site

As of December 2018, EPA did not have economic data related to on-site businesses, or economic data were not applicable due to site use. View information about redevelopment economics at Superfund sites.

Top of Page