# Cottage Grove *City in Washington County, Minnesota; site of a 3M plant and of PFAS contamination pursued by state agencies* Cottage Grove is a city in Washington County, [[Minnesota]]. It sits on the northern bank of the [[Mississippi River]], roughly 10 miles south of Saint Paul, within the [[Minneapolis]]–Saint Paul metropolitan area.[^1] The 2020 census counted 38,839 residents. 3M has run a production facility in the city since 1947.[^1] The [[Minnesota Pollution Control Agency]] (MPCA) lists 3M Cottage Grove as one of four East Metro 3M PFAS contamination sites. The agency states that the contamination covers "more than 150 square miles" and affects the drinking water of "more than 140,000 Minnesotans."[^2] The State's complaint against 3M in [[Hennepin County District Court]], No. 27-CV-10-28862, names 3M Cottage Grove among four sites.[^3][^4] Press coverage reports that in May 2026 the MPCA filed a further suit in [[Washington County District Court]] over continuing contamination from Cottage Grove.[^5] The State's own documents frame the record. In 2004 the [[Minnesota Department of Health]] (MDH) classified the PFC releases at 3M Cottage Grove as "an indeterminate public health hazard." It gave the reason that there were not sufficient environmental data. The same document recorded wells exceeding then-current health values "sometimes by a factor of 100 or more."[^6] The MPCA / 3M Settlement [[Working Group]] notes for Fall 2025 record $515 million in capital commitments. The estimated need by the end of FY2026 is $575 million.[^7] ## What The 3M plant has operated since 1947. It makes adhesives, industrial polymers and reflective materials for road signs, and it also houses research and development work.[^1] Perfluorochemical (PFC) output there started as a pilot around 1947. Commercial-scale PFOA production ran from 1976 until it was phased out in 2002.[^1] Wikipedia places the Cottage Grove site in the MPCA's Superfund program for perfluorochemical contamination.[^1] The MPCA lists four East Metro sites: 3M Oakdale, 3M Woodbury, 3M Cottage Grove (Chemolite) and the [[Washington County Landfill]]. It states that the county landfill is handled under the state Closed Landfill Program, not under Superfund.[^2] The State's complaint pleads six counts:[^3][^4] - the Minnesota Environmental Response and Liability Act (MERLA); - the Minnesota Water Pollution Control Act; - trespass; - common-law nuisance; - statutory nuisance; - negligence. The State sues as trustee under Minn. Stat. § 115B.04. The complaint names four sites: 3M Cottage Grove, the 3M [[Oakdale Disposal Site]], the 3M Woodbury Disposal Site and the Washington County Landfill at [[Lake Elmo]]. It also names four chemicals: PFOA, PFOS, PFBA and PFBS.[^3] The May 2026 suit, as reported by the Pioneer Press, concerns continuing PFAS contamination of groundwater and the Mississippi River from Cottage Grove. The report says the suit cites 47 industrial and stormwater outfalls. It seeks civil penalties of up to $30,000 per violation per day, expanded groundwater extraction, injunctive relief and natural resource damages.[^5] According to the same report, a 2018 release does not bar the suit, because the contamination at issue was discovered in 2020.[^5] The pack carries no docket number or current status for this suit. ## When - 1871: Cottage Grove is platted.[^1] - 1947: 3M opens its Cottage Grove facility, and pilot PFC production begins.[^1] - 1950s–1970s: The MPCA states that disposal at the East Metro sites took place "from the 1950s through the early 1970s."[^2] 3M's exhibit PTX1872 gives other dates for Cottage Grove off-site disposal:[^8] - Oakdale, 1956–1960; - Woodbury, 1960–1965; - the Washington County Landfill, "Mid 1970s/Early 1990s." - 1976–2002: 3M produces PFOA at commercial scale until the phase-out.[^1] - Early 2000: According to the project's at-issue record, PFOA in effluent from Cottage Grove's wastewater treatment plant reaches an overall high of 1,991 micrograms per liter.[^9] - 2004: MDH classifies the 3M Cottage Grove PFC releases as "an indeterminate public health hazard."[^6] - 2006: Filtration is installed. MDH reports that long-term residents exposed before 2006 showed declining but still elevated PFC levels.[^10] - 2007: The [[2007 Consent Order]] is entered. The settlement's projects are to transition back to this order.[^7] - 2008: MDH begins East Metro biomonitoring. The pilot detects PFCs in 100% of participants.[^10] - 2014: An MDH round tests blood from more than 300 residents of Oakdale, Lake Elmo and Cottage Grove.[^10] - 2024: A federal drinking-water limit for PFOA of 4.0 nanograms per liter is set.[^9] - Fall 2025: The Working Group records a capital shortfall of about $26 million.[^7] - May 2026: The MPCA sues 3M in Washington County District Court, according to press coverage.[^5] - Second half of 2027: The transition back to the 2007 Consent Order is "estimated to be in the second half of calendar year 2027."[^7] ## Where - Location: About 10 miles south of Saint Paul, according to Wikipedia's lead. The geography section of the same article gives 11 miles southeast.[^1] - Roads: U.S. Highway 61 and Interstate 494 serve the city.[^1] - Area: The [[United States Census Bureau]] gives 37.48 square miles in total, with 33.62 square miles of land and 3.86 of water.[^1] - Riverfront: No other Minnesota city has more land along the Mississippi River.[^1] - Neighbors:[^1] - [[Woodbury]] to the north; - [[Hastings]] to the south; - St. Paul Park to the west; - Newport to the northwest; - Denmark Township to the east. - Wisconsin: The city's southeastern part lies five miles from the Wisconsin border.[^1] - Congressional district: Cottage Grove is in Minnesota's 2nd congressional district, represented by [[Angie Craig]].[^1] - Wastewater discharge: The project's at-issue record states that Cottage Grove's wastewater treatment plant discharged to the Mississippi River for decades.[^9] - Landfill: Exhibit PTX1872 identifies the Washington County Landfill as the "Lake Jane Landfill." It lists the owner as "Washington County" and the waste as "WWTP sludge and boiler ash."[^8] The complaint places the landfill in Lake Elmo.[^3] ## How much - MPCA funding totals: The MPCA's FY2025 legislative report gives community project funding of $110,224,231 for Cottage Grove. The other totals are:[^11] - Woodbury, $251,960,201; - Lake Elmo, $2,353,000; - Newport, $1,918,950; - Hastings, $1,440,500; - total key projects, $369,316,077. - Fall 2025 notes: The Working Group's notes record the following:[^7] - $515 million in cumulative capital commitments; - an estimated $575 million of need by the end of FY2026; - a capital shortfall of about $26 million; - about $137 million projected to be unobligated at the end of FY2026. - Project status: The same notes place Cottage Grove and Oakdale on temporary systems. They record Woodbury and Hastings as under construction and over budget.[^7] - Star Tribune reporting: The *[[Star Tribune]]* reported the following:[^12] - the fund "could run out by 2027"; - Hastings needs $68.9 million and has received $14 million, and is raising rates to cover roughly $54.9 million; - 3M is contesting whether projects meet the "reasonable and necessary" standard under the 2007 Consent Order. - Civil penalties: The May 2026 suit seeks penalties of up to $30,000 per violation per day, as reported.[^5] ## How many - Contamination extent: The MPCA gives "more than 150 square miles" of contamination, four sites, and "more than 140,000 Minnesotans" whose drinking water is affected.[^2] - The complaint: six counts, four sites and four chemicals.[^3] - Wells: The *Star Tribune* reported that all 12 Cottage Grove wells exceed PFAS limits, as do all six Hastings wells.[^12] - Biomonitoring: MDH has run three projects since 2008. The 2008 pilot detected PFCs in 100% of participants. The 2014 round tested more than 300 residents.[^10] - Outfalls: The May 2026 suit cites 47 industrial and stormwater outfalls, according to press coverage.[^5] ## In the at-issue record - **Settlement funding.** The Working Group's Fall 2025 notes give the trustees' own arithmetic: $515 million committed, against an estimated $575 million of need by the end of FY2026. The notes estimate the handoff back to the 2007 Consent Order for the second half of 2027.[^7] Beside those figures, the *Star Tribune* reported two facts. All twelve Cottage Grove wells exceed PFAS limits. Hastings needs $68.9 million and has received $14 million.[^12] - **Effluent and the federal limit.** The at-issue record gives an overall high of 1,991 micrograms per liter of PFOA in early 2000. The sample was taken from the effluent of Cottage Grove's wastewater treatment plant, which discharged to the Mississippi for decades. The federal drinking-water limit set in 2024 is 4.0 nanograms per liter.[^9] - **MDH's 2004 classification.** MDH called the releases "an indeterminate public health hazard." It stated that impacts "cannot be fully assessed by MDH at this time, because there are not sufficient environmental data available." The same document recorded wells exceeding then-current health values "sometimes by a factor of 100 or more."[^6] ## Notes [^1]: Wikipedia contributors, *Cottage Grove, Minnesota* (revision 1379795739, retrieved 2026-10-27) — population, location, area, borders, 3M facility history, Superfund listing, congressional district. https://en.wikipedia.org/wiki/Cottage_Grove,_Minnesota [^2]: Minnesota Pollution Control Agency, *East Metro 3M PFAS contamination* (web page; date not stated in pack) — extent of contamination, the four sites, disposal period, and Closed Landfill Program handling of the county landfill. https://www.pca.state.mn.us/local-sites-and-projects/east-metro-3m-pfas-contamination [^3]: Hennepin County District Court, *State of Minnesota v. 3M Company*, Complaint, No. 27-CV-10-28862 (filing date not stated in pack) — six counts, trustee standing under Minn. Stat. § 115B.04, four sites, four chemicals. https://www.ag.state.mn.us/Office/Cases/3M/docs/Complaint.pdf [^4]: Minnesota Attorney General's Office, *State of Minnesota v. 3M Company* case page (date not stated in pack) — case record for No. 27-CV-10-28862. https://www.ag.state.mn.us/Office/Cases/3M/ [^5]: Pioneer Press via *Spokesman-Review*, *Minnesota sues 3M again over PFAS pollution* (May 24, 2026) — news report of the MPCA suit in Washington County District Court: 47 outfalls, the relief sought, and the 2018 release and 2020 discovery. https://www.spokesman.com/stories/2026/may/24/minnesota-sues-3m-again-over-pfas-pollution/ [^6]: Minnesota Department of Health, *3M Cottage Grove* public health document (2004) — "indeterminate public health hazard" classification, the stated data limitation, and wells exceeding health values by a factor of 100 or more. https://www.health.state.mn.us/communities/environment/hazardous/docs/sites/washington/3mcg0205.pdf [^7]: Minnesota Pollution Control Agency / 3M Settlement Working Group, *Fall 2025 — Notes* (Fall 2025) — $515 million committed against $575 million of need, ~$26 million shortfall, ~$137 million unobligated, project status, and the 2027 transition to the 2007 Consent Order. https://3msettlement.state.mn.us/sites/3msettlement/files/2025-12/Fall%202025%20-%20Notes.pdf [^8]: 3M, *Off-Site Waste Disposal Locations — 3M Cottage Grove*, State's trial exhibit PTX1872 (date not stated in pack) — corporate document produced in litigation: disposal sites, years, landfill owner and waste types. https://www.ag.state.mn.us/Office/Cases/3M/docs/PTX/PTX1872.pdf [^9]: U.S. Environmental Protection Agency, *Per- and Polyfluoroalkyl Substances (PFAS)* drinking-water page (date not stated in pack) — the 2024 federal limit. This is the anchor of at-issue row AI-Washington-061, which also records the early-2000 effluent reading and the Mississippi discharge. https://www.epa.gov/sdwa/and-polyfluoroalkyl-substances-pfas [^10]: Minnesota Department of Health, *East Metro PFAS biomonitoring* (date not stated in pack) — three projects from 2008, the 2008 pilot's 100% detection, the 2014 round of more than 300 residents, and the 2006 filtration. https://www.health.state.mn.us/communities/environment/biomonitoring/projects/pfas.html [^11]: Minnesota Pollution Control Agency, *FY2025 legislative report on PFC projects* (FY2025) — community project funding totals by city. https://www.pca.state.mn.us/sites/default/files/lrc-pfc-2sy25.pdf [^12]: *Star Tribune*, *3M settlement, Minnesota PFAS water* (date not stated in pack) — news report: fund could run out by 2027, well exceedances in Cottage Grove and Hastings, Hastings funding gap, 3M's "reasonable and necessary" challenge. https://www.startribune.com/3m-settlement-minnesota-pfas-water/601287204