PFC investigation and clean up

Perfluorinated chemicals (PFCs) were first found to have contaminated drinking water supplies in parts of the eastern Twin Cities in 2004. The MPCA and Minnesota Department of Health (MDH) identified contaminated wells and the MPCA provided clean drinking water. Most of the contamination was traced to four dumps or landfills.

The known drinking-water problems are under control and cleanup plans for three of the four waste sites have been approved. The MPCA’s focus on PFCs is shifting to investigating use of PFC-containing foams at firefighting training sites and PFCs in the ambient environment.


PFCs are a family of synthetic chemicals, initially developed by the 3M Company, that have been used for decades to make products that resist heat, oil, stains, grease, and water. 3M has phased out manufacture of some PFCs, but there are currently other manufacturers of PFCs around the world.

From the 1950s through the early 1970s, 3M disposed of wastes from PFC manufacturing primarily in four places: dump sites in Oakdale and Woodbury, the 3M manufacturing facility in Cottage Grove, and the Washington County Landfill. In late 2003, the MPCA discovered PFCs in groundwater at and near some of these sites.

In 2004, MPCA began sampling monitoring wells at the disposal sites and nearby private wells, and the MDH sampled city wells in Washington County to identify drinking-water supplies with PFCs. Sampling soon expanded to a wider area of the east Metro.

More than 1,600 private wells were sampled, along with more than 50 community wells. Both private and community wells were affected, including a number of private wells in Lake Elmo, Cottage Grove, Grey Cloud Island Township, and several of the city of Oakdale’s wells. Based on PFC levels found in some wells, MDH advised 83 households not to drink their water due to PFCs.

Concurrent with these activities, staff in the MPCA’s Superfund Program and Closed Landfill Programs conducted and ordered investigations for PFCs related to the four waste sites. The sites had all been previously investigated for other contaminants, so a great deal was known about their subsurface geology, groundwater and past disposal practices.

MPCA actions

The MPCA is involved in a number of activities related to cleanup and research about perfluorinated chemicals, or PFCs. Some of the most notable of these include:

  • Working with the Minnesota Department of Health to sample private and municipal drinking water supplies;
  • Evaluating closed and active landfills that may have accepted waste containing perfluorooctane sulfate (PFOS) and perfluorooctanic acid (PFOA);
  • Sampling Mississippi River sediment and discharge from outfalls at the 3M Cottage Grove facility;
  • Sampling effluent from a number of wastewater treatment plants statewide, including the Twin Cities metro plants
  • Fish tissue sampling;
  • Review and oversight of 3M's investigation and cleanup plans for sites in the Superfund program;
  • Coordination of information with the U.S. Environmental Protection Agency (EPA) about PFOA; and
  • Developing water-quality criteria for surface water discharge of PFOS and PFOA.


Health information

The Minnesota Department of Health (MDH) is responsible for setting limits for contaminants in drinking water. Because PFCs are present in drinking water in some areas, the MDH developed criteria, known as Health Based Values (HBVs), for PFOA and PFOS. HBVs are criteria that MDH considers safe for human consumption over a lifetime.

In May 2017, MDH issued revised HBVs for PFOA (35 parts per trillion) and PFOS (27 parts per trillion). For more information, visit Minnesota Department of Health website.

For information on removing PFCs from drinking water, please see the following MDH fact sheet: PDF icon MDH evaluation of point-of-use water treatment devices for perfluorochemical removal - Summary (MDH)

What are PFCs?

Perfluorochemicals or PFCs are a family of proprietary 3M chemicals that have been used for decades to make products that resist heat, oil, stains, grease and water. In the past, PFCs including perfluorooctane sulfate (PFOS), perfluorooctanic acid (PFOA), and perfluorobutanoic acid (PFBA) were not regulated. 

Common uses include nonstick cookware, stain-resistant carpets and fabrics, components of fire-fighting foam, industrial applications, coatings for packaging such as milk cartons, cosmetic additives and other personal products. 

The chemical structures of PFOS and PFOA make them extremely resistant to breakdown in the environment. PFOS and PFOA are bioaccumulative in humans and animals. Less is known about PFBA.

What is the PFC connection to Minnesota?

The 3M chemicals that contain PFOS, PFOA and other PFCs were produced in Minnesota at the 3M Chemolite facility in Cottage Grove. Historically, production waste from 3M was disposed of in Minnesota at the Cottage Grove site as well as 3M Oakdale (Superfund site) and the Washington County Landfill (a Closed Landfill Program site). The MPCA has also been looking at other sites that may have accepted 3M production waste containing PFOS, PFOA, and other PFCs. 

It is important to note that a number of consumer products that used Scotchguard (produced by 3M) or Teflon (produced by Dupont) may contain various PFCs. In 2002, 3M stopped using PFOS and PFOA in Scotchguard products. The company announced this phase out in 2000.    

There are still other PFCs generated by 3M. The MPCA may require 3M to conduct additional investigation or testing to ensure that current PFC generation does not pose a risk.

Sampling and pilot test for ground-water treatment at Washington County Landfill

The Closed Landfill Program (CLP) began PDF icon ground-water sampling for PFOS and PFOA at the Washington County Landfill in the spring of 2004. PFOA was found in the groundwater at low levels. The MDH laboratory expanded the PFC analysis to seven compounds in early 2005; in response sampling was expanded to residential wells near the landfill in Lake Elmo and Oakdale.

The CLP completed a pilot test on anionic resins at the Washington County Landfill for treatment of groundwater contaminated with PFOS, PFOA and PFBA, and also completed laboratory tests on activated carbon as a potential treatment method during the summer of 2007. The CLP is looking at the design and associated costs of building and operating an onsite treatment system and is evaluating a range of other potential corrective actions, including a design to dig up the landfill, create a lined site, and place the wastes back on the liner.

Sampling in Lake Elmo and Oakdale

The MPCA and MDH have sampled over 500 private residential wells in Lake Elmo and seven wells in Oakdale as of September 2007. So far, 166 residential wells in Lake Elmo and one in Oakdale have PFCs in excess of the well advisory guidelines set by MDH. Residents exceeding the well advisory guidelines have received bottled water until granular-activated carbon (GAC) filter systems were installed or city water was connected to their homes. The MPCA has been coordinating bottled water efforts and GAC installations for those that have not been connected to municipal water in Lake Elmo.

An additional 177 private wells have been found to contain low concentrations of PFCs, below MDH guidelines. Fifty-nine private wells in Lake Elmo and six in Oakdale were found to contain no PFCs.  

MPCA and MDH staff are also tracking stormwater impacts on the PFC plume. Historical research is ongoing to determine the interactions between Lake Jane and Sunfish Lake, Raleigh Creek and Eagle Point Lake, and Eagle Point Lake and Lake Elmo. Targeted sampling of residential wells between these surface water features is assisting staff in defining the PFC plume.

Active landfill evaluation for PFCs

In 2006, the MPCA developed a strategy to screen open solid waste facilities in Minnesota for the presence of PFCs. As part of this strategy, the MPCA looked at various landfill types that did not receive production waste from the 3M Cottage Grove facility. The screening results are being used to assess the impacts associated with PFC contamination generated from residential, commercial, and industrial products in the waste stream. Results from continuation of this work in 2007 are available below:

Sediment and fish tissue sampling for PFCs from the Mississippi River and metro-area lakes

Sediment cores and river water were collected upstream and downstream of the 3M discharge to the Mississippi River from the Cottage Grove facility. PFC contaminant levels between 10 and 99 parts per billion were found in river core sediments. This may be significant, however the aquatic and ecological effects are unknown. The MPCA has developed water-quality criteria numbers for surface-water discharge of PFOS and PFOA (see below).

The MDH periodically revises the Fish Consumption Advisories to include guidelines for eating fish contaminated with PFCs. Advices have been issued for fish from Pool 2 of the Mississippi River (the section of the Mississippi between the Ford Dam and Hastings) that may contain PFOS and PFOA and, in 2007, for a number of lakes in the Twin Cities metropolitan area. More results from testing on metro lakes and other state waters will be available in late 2007. Check the MDH Web site for most current fish-consumption advice related to PFCs.

Water-quality criteria for PFOA and PFOS

In January 2006, the MPCA began developing ambient surface-water quality criteria for perfluorooctanic acid (PFOA) and perfluorooctane sulfonic acid (PFOS). Site-specific criteria were finalized in August 2007. The method that was to be used to develop this criterion is that published in Minnesota Rules, Chapter 7050.0218 Methods for Protection of Surface Waters from Toxic Pollutants for Which Numerical Standards Not Promulgated. This effort entails the development of the specific values for a chemical.

MPCA investigation and cleanup of 3M PFC waste sites

The MPCA provides oversight of work plans or actions related to PFC contamination at three sites — 3M Chemolite site, 3M Woodbury site, and 3M Oakdale site — under the state Superfund program. A fourth site, the Washington County Landfill, is being addressed under the state Closed Landfill Program.

In the spring of 2007 the MPCA and 3M negotiated a Consent Order bringing investigation and cleanup of the three sites under the formal Superfund process. The Order was approved by the MPCA Citizens’ Board in April 2007. Submittals required under the Consent Order and other selected documents related to the four sites are available on the PFC Cleanup Sites webpage.

PFC-containing firefighting foam — MPCA/MDH investigation

In the spring and summer of 2008 the MPCA surveyed Minnesota fire chiefs about their departments' use of PFC-containing firefighting foams. Based on the survey results, MPCA and MDH are jointly investigating the possibility that PFCs may be found in soil or groundwater at fire-training sites that used PFC-containing Class B firefighting foams. Starting in spring 2009 MPCA sampled selected firefighting training sites  and MDH sampled municipal wells near about two dozen of those locations.

As of July 2009, most of the samples had been collected, and results are in various stages of quality checking. At a couple of training sites there were a few detections of PFCs in groundwater that exceeded established Health Risk Limits (HRLs) for PFOA, but MDH found no exceedances of any drinking-water standard in municipal wells.

U.S. EPA activities for PFOA and other PFC compounds

The U.S. Environmental Protection Agency (EPA) received information in the late 1990s indicating that PFOS was widespread in the blood of the general population and presented concerns for persistence, bioaccumulation, and toxicity. After 3M terminated production of PFOS, EPA began review in 2000 of similar chemicals including PFOA.

In January 2005, the EPA’s Office of Pollution Prevention and Toxics submitted a Draft Risk Assessment of the Potential Human Health Effects Associated With Exposure to Perfluorooctanoic Acid and Its Salts (PFOA) to the EPA Science Advisory Board for public peer review. EPA sought this early stage scientific peer review from an outside panel of experts to ensure the most rigorous science in evaluation of PFOA. It is important to note that the draft assessment is preliminary and does not provide conclusions regarding potential levels of concern, but does highlight the scientific approaches to be used developing the EPA’s revised PFOA risk assessment.

In January 2006, EPA invited companies responsible for PFOA and related chemicals to enter a stewardship program.

Fact sheets and presentations