The inactive 37.5-acre Sussex County Landfill No. 5, located in Laurel, Sussex County, Delaware, was operated by Sussex County from 1970 until 1979. The landfill accepted mixed municipal and industrial wastes and, according to a 1978 Congressional report, an unknown quantity of various volatile organic compounds (VOCs). In certain areas of the landfill, wastes were deposited in the ground below the water table, threatening groundwater.

During 1992, Sussex County conducted an investigation at the site which included the installation of several additional monitoring wells and sampling of ground water, surface water, air, soil, and sediments. This investigation confirmed that the ground water is contaminated primarily with very low levels of VOCs (e.g., benzene and vinyl chloride) and that ground water is the primary concern at this site.

The landfill overlies the Columbia Formation, which is connected to and recharges the Manokin Aquifer. Together, the two aquifers provide drinking water to people within three miles of the site. Public and private wells within three miles of the site provide drinking water to an estimated 5,700 people and irrigate 5,100 acres of cropland.

After initial actions, EPA took the site off the Superfund program’s National Priorities List  in 2001. Operation and maintenance activities and groundwater monitoring are ongoing.