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Congressional District # 06


EPA ID# MND980904056
Last Updated: February, 2012

Site Description

The 104-acre Oak Grove Sanitary Landfill site was operated as an open dump until 1971, when the Minnesota Pollution Control Agency (MPCA) issued a permit to the owner for a sanitary landfill. In 1976, operations were taken over by Northwest Disposal Inc. until closure in 1984. Approximately one-half million cubic yards of wastes, including garbage, various sludges and acids, pesticide manufacturing waste, paint, cutting oils, cleaning solvents, and inks were disposed of at the landfill. The Minnesota Department of Health sampled nine nearby residential wells in 1984. The wells are screened in a sand aquifer, which is the primary water supply source in the area. Samples from three wells indicated the presence of several volatile organic compounds (VOCs) and metals. Subsequent resampling did not detect these compounds. In 1985, lime sludge was used as a cover for part of the landfill.

Approximately 330 people live within one mile of the site, and 9,800 people live within four miles. The majority of these residents depend on water from wells. However, the lower aquifer is used for residential drinking water and does not pose a risk to human health. A creek flows through the site and is adjacent to a wetland, discharging to the Rum River two miles from the site. 

Site Responsibility

This site is being addressed through state actions.  The property is owned by the State of Minnesota and is operated and maintained by the state as part of the state's Closed Landfill Program.

Threats and Contaminants

Methane and VOCs were detected beneath the lime sludge cover material. VOCs, phenols, phthalates, and heavy metals were detected in the upper aquifer. Leachate samples indicated the presence of VOCs, phenols, and heavy metals. Several VOCs, phenols, and heavy metals were found in sediment samples and surface water at the site. 

Cleanup Progress

In 1988, MPCA and the United States Environmental Protection Agency (U.S. EPA) selected the following cleanup actions for the source area operable unit: installation of a security fence; capping with a multilayer cover system; installation of a topsoil cover and vegetation; enforcement of deed restrictions; consideration of treatment options for air emissions from gas vents after construction of the final cover; and air and groundwater monitoring.  In 1991, U.S. EPA selected a remedy for the remainder of the site, know as Operable Unit 2.  This remedy included long-term monitoring of the shallow and deep aquifers, surface waters, and sediments; and institutional controls on the installation of drinking water wells around the landfill, including proper plugging of nonessential water wells. 

In 1992, U.S. EPA issued a unilateral administrative order (UAO) to potentially responsible parties (PRPs), requiring them to design and implement the cleanup. Work was completed in 1993.  The site was deleted from U.S. EPA's National Priorities List on October 17, 1997.  

During the late 1990's, monitoring found that the active gas extracton system was functioning poorly during freezing weather.  Construction of a new gas extraction system with an enclosed flare was completed in 2003.  The most recent five year review conducted for the site in 2007 confirms that the remedy remains protective of human health and the environment.


Remedial Project Manager, U.S. EPA
leah evison (evison.leah@epa.gov)
(312) 886-2064

Community Involvement Coordinator, U.S. EPA
Don De Blasio
(312) 886-4360




Site Profile Information

This profile provides you with information on EPA's cleanup progress at this Superfund site.


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