Hazardous Sites and Substances in Minnesota
3M Woodbury Site
February 2007


The 3M Woodbury Site is located approximately six miles south of Interstate 94 along the border of Cottage Grove and Woodbury (between Co. Rd 19/Woodbury Drive and Lamar Ave just north of 67th Street). Since 1992, the site has been in the Voluntary Investigation and Cleanup (VIC) Program at the Minnesota Pollution Control Agency (MPCA).

The site consists of three disposal locations used for disposal of solid waste, industrial solvents and acids from 3M's Cottage Grove and Saint Paul manufacturing facilities during the 1960s. Woodbury and Cottage Grove residents also used the site for dumping municipal waste (such as household, automotive, construction, and commercial debris). In 1966 isopropyl ether, an industrial solvent, was discovered in a shallow well on a nearby property. This prompted further investigation of the site and more extensive well testing for area residential wells. A variety of hazardous substances, particularly volatile organic compounds (VOCs), were found at the site in both the soil and groundwater. However, no drinking water wells were found to be contaminated.

3M has taken voluntary actions since the late 1960's to address soil and groundwater contamination. Some of the actions taken include: excavation of disposal trenches and burning waste on site, re-grading the property with a layer of compacted soil over disposal areas; fencing certain areas around the site; regular testing of on-site and off-site groundwater monitoring wells, barrier wells, and residential wells; and installation of four groundwater pump-out wells to contain the spread of contaminants in the groundwater. This pump-out system carries the extracted groundwater by pipeline to the 3M Cottage Grove plant where it is used for non-contact cooling water and then discharged to the Mississippi River.

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PFCs at the 3M Woodbury Site

The 3M Woodbury Site was used as a disposal site for perfluorochemical (PFC) waste. PFCs are a family of manmade chemicals that have been used for decades to make products that resist heat, oil, stains, grease and water. They were produced in the late 1940s until 2002 by 3M at its Cottage Grove facility.

In spring 2005, low levels of perfluorooctanoic acid (PFOA) and perfluorooctane sulfonate (PFOS) were detected in the pump-out system at the 3M Woodbury site, prompting an investigation of residential wells by MDH and MPCA. Fifteen private wells located near the 3M Woodbury site were sampled in June to determine if PFCs were migrating from the dump in groundwater. These wells were chosen based on their depth and location to provide information about concentrations in different aquifers underneath this area. PFOS and PFOA were not detected in any of the private wells.

In spring 2006, the MDH Public Health Laboratory expanded its PFC analytical method to include five additional PFCs. Of the five, perfluorobutanoic acid (PFBA) has recently been found to be widespread in groundwater south of two other 3M waste disposal sites, the former Washington Co. Landfill in Lake Elmo and the Oakdale Dump, and extending south into the city of Woodbury. 

PFBA appears to be very mobile in the environment, more so than PFOS or PFOA.  Once in the environment, it does not break down. The MPCA requested that 3M sample monitoring wells at the 3M-Woodbury disposal site for additional PFCs.  Those results indicate that PFBA is present at several on-site monitoring wells.

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PFCs in South Washington County

In December 2006, as part of a regional evaluation of PFBA in groundwater, the city wells in Cottage Grove, Newport, and St. Paul Park were sampled for PFCs.  PFBA was detected in all of the wells tests, (See map PFCs in the Southeast Metro Area (PDF: 669KB/ 1 page)), but neither PFOA nor PFOS was found. The source of PFBA in these wells has not yet been determined. However, groundwater in the area flows to the south and southwest; therefore the city wells are downgradient (or “downstream”) from the 3M-Woodbury Disposal Site.

Additional samples collected in January 2007 have detected PFBA at a low level in a community well in Denmark Township. PFBA is present at very low levels in one well in South St. Paul and two wells in Hastings. Taken together, the concentration and distribution of PFCs suggest that the contamination in the Cottage Grove-St. Paul Park-Woodbury- Newport area is not related to the contamination in Lake Elmo, Oakdale, and Woodbury.

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What Actions Are Being Taken?

MDH and MPCA are moving quickly to evaluate the extent of the contamination of the groundwater in south Washington County. Non-community public wells (e.g. businesses, churches, parks, etc.) are being sampled throughout the southern portion of Washington County. The original 15 private wells near the 3M-Woodbury Disposal site have been sampled for the expanded PFC list and additional private wells will be selected for testing based on the sampling results.

MDH and MPCA are working with the affected cities, Washington County, Dakota County, and elected officials from the area to determine what additional actions will be needed to protect public health. As the investigation progresses, MDH and MPCA will keep the public informed of what we are finding.

For more information, please visit our websites:

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Perfluorochemical Contamination in Southern Washington County, Northern Dakota County, and Southeastern Ramsey County, Minnesota - January 5, 2012 (PDF: 6170KB/162 pages)
Sampling Map for 3M Woodbury Site
PFCs in the Southeast Metro Area map (PDF: 669KB/1page)
The 3M Cottage Grove Facility and Perfluorochemicals
VOCs: Volatile Organic Chemicals in Private Drinking Water Wells
Minnesota Pollution Control Agency: Perfluorochemicals

Overview: Perfluorochemicals and Health
Washington County Landfill
Update: Perfluorochemicals and the City of Oakdale Public Water Supply
City of Oakdale
Lake Elmo Private Wells
City of Lake Elmo
3M Oakdale Site
Bottled Water: Questions and Answers
MDH Evaluation of Point-of-Use Water Treatment Devices for Perfluorochemical Removal Interim Report (PDF: 36KB/2 pages)
Water Treatment Using Carbon Filters: GAC Filter Information

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Updated Wednesday, May 28, 2014 at 08:35AM