Region 5 Superfund

U.S. EPA REGION 5
WASHINGTON COUNTY
LAKE ELMO

Congressional District # 06

WASHINGTON COUNTY LANDFILL

EPA ID# MND980704738
Last Updated: August, 2012

Site Description

The Washington County Landfill site is a municipal landfill that accepted municipal and industrial waste materials from 1969 to 1975.  The landfill was located in a former sand and gravel quarry and prior to its use for industrial waste disposal it was used as a sanitary landfill.  The landfill encompasses approximately 35 acres and contains an estimated 2.57 million cubic yards of waste.  The solid waste is comprised of 73% residential wastes, 26% commercial wastes, and 1% demolition wastes including waste from 3M Corporation.  The area adjacent to the landfill is predominantly residential, with some areas used for farming.  There is a city park located to the east and Lake Jane is 250 feet north of the property boundary.  There are aproximately 3,000 people living within a three-mile radius of the landfill.

The site was listed on the United States Environmental Protection Agency’s (EPA’s) National Priorities List in 1984

Site Responsibility

This site has been addressed through Federal, State, County and potentially responsible party actions.  Currently, the site is operated and maintained by the Minnesota Pollution Control Agency (MPCA) as part of its Closed Landfill Program.

Threats and Contaminants

Volatile organic compounds (VOCs) were present in soil and groundwater on-site and in groundwater of certain off-site private wells.  In 2004, perfluorochemicals (PFCs) were also found in on-site groundwater and in some offsite residential wells.

Cleanup Progress

In 1975, the landfill was closed and a 2-foot landfill cover was installed.  In 1981, VOCs were detected in groundwater beneath the landfill and additional monitoring wells were constructed.  In response to a Order by Consent from MPCA, beginning in 1984, Washington and Ramsey Counties installed a groundwater gradient control system to capture contaminated groundwater and a spray irrigation system to treat the water. 

Construction of a new water supply system was initiated in 1991.  An Administrative Order was issued by EPA to the counties in 1992, and  amended in 1993, to continue the remedial actions.  Connection of 10 residences to the water supply system was completed in 1992.  Connection of the remaining 71 residences was completed in 1993.  

In the early 1990s, a gas explosion occurred on the site due to faulty wiring and pressure build-up.  In response, fourteen extraction vents were installed in 1993 on the edge of the landfill (primarily at the western boundary) to capture methane migrating toward homes and municipal buildings and release it near the center of the landfill.  In 1996, MPCA installed an enclosed flare and active gas extraction system.  At this same time, MPCA conducted a major upgrade to the landfill cap.  In 1996, the MPCA and the EPA terminated the Administrative Order and put the site in long-term management under MPCA’s Closed Landfill Program.  EPA then deleted the site from the NPL.  

In 2004, the MPCA found PFCs in on-site monitoring wells and also in some downgradient residential wells.  At about this time, scientific studies had been performed documenting the risks from PFCs and improved laboratory detection limits now allowed better detection of PFCs.  Since 2005, the MPCA and the Minnesota Department of Health (MDH) have sampled 404 residential wells for PFCs.  One hundred residences were placed on bottled water because they were advised by MDH not to drink their water.  The MPCA placed granular carbon filters on an additional 22 residences in 2006. 

In 2007, the MPCA and 3M Corporation signed a Consent Order under the Minnesota Environmental Response and Liability Act (MERLA) on PFC contamination issues in Minnesota.  Further cleanup of the Washington County Landfill was included as part of the Consent Order.  The cleanup plan included excavation of the landfill and placement of the waste into triple-lined cells on-site.  The triple lined cells will prevent further escape of any contamination from the site.  Construction began in 2009 and is nearing completion.   

The latest Five-Year Review, signed in March 2009, documents that the current remedy as implemented is protective of human health and the environment in the short term because exposure pathways are being controlled.  The site will be protective in the long term following review of insitutional controls and lowering of contaminant concentrations in groundwater.

Contacts

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

Aliases

WASHINGTON COUNTY LDFL

 

Site Profile Information

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