Yes. PFOA released into the air can travel downwind, deposit onto soil, move downward with infiltrating water and eventually contaminate groundwater and drinking-water wells. That is not merely a theory invented for a new lawsuit against 3M. Federal researchers recognize the pathway, and peer-reviewed studies have documented PFOA in groundwater miles downwind of industrial air-emission sources.
What is not yet established is the more specific allegation now being made by Hastings, Minnesota: that historical PFOA emissions from 3M’s Cottage Grove facility traveled southeast through the atmosphere and ultimately caused the contamination in Hastings municipal Wells 3, 4, 6, 7 and 8.
That distinction matters.
The physical mechanism is scientifically credible. Some of the historical emissions are documented. The geography is consistent with the city’s theory. And Hastings points to several additional clues, including PFAS chemical fingerprints and patterns in groundwater.
But the lawsuit was filed on August 26, 2026. Its strongest case-specific conclusions have not yet been tested in court, and some of the underlying data and modeling cited in the complaint are not publicly available in the materials sherafy.com could review.
The best-supported conclusion right now is therefore narrower than either side of a sensational headline:
A smokestack-to-soil-to-groundwater pathway is real. Hastings has assembled evidence consistent with that pathway. How much of the PFOA in these five wells actually came from historical 3M air emissions remains an unresolved question of source and transport attribution.
How can pollution in the air end up in groundwater?
The process sounds counterintuitive because groundwater contamination is usually pictured as something being dumped directly onto the ground or spilled into water.
Air pollution can take a longer route:
Industrial emission → atmospheric transport → wet or dry deposition → contaminated surface soil → infiltration with rain or snowmelt → groundwater → drinking-water well
PFOA is a member of the larger PFAS family. It is extremely persistent, and its environmental behavior allows it to move through water and, under some conditions, through soil.
The Minnesota Department of Health and the federal Agency for Toxic Substances and Disease Registry were discussing this exact possibility at 3M’s Cottage Grove facility more than 20 years ago.
Their 2005 health consultation noted that PFOA could be released into the atmosphere in vapor and particulate forms, undergo wet or dry deposition, and show high mobility in some soils. The report specifically concluded that infiltration could carry deposited contamination toward groundwater. (Minnesota Department of Health)
Modern EPA research goes further. EPA says atmospheric PFAS emissions, transport and deposition can contribute to contamination of surface water, groundwater and private wells around industrial point sources. A 2021 EPA-led modeling study of a fluorochemical facility in North Carolina modeled PFAS movement through the atmosphere over roughly 150 kilometers and quantified deposition downwind. (US EPA)
So the first question is relatively easy to answer:
No, PFAS does not have to be dumped directly into groundwater to get there.
Scientists have seen the air-to-groundwater pathway elsewhere
Hastings is not asking a court to recognize an environmental mechanism with no real-world precedent.
A particularly useful comparison comes from Vermont and eastern New York.
Researchers examined widespread PFOA contamination around facilities that had historically emitted PFAS into the air. Some contaminated areas were uphill or otherwise difficult to explain through conventional groundwater flow from the factories.
The researchers sampled soils, springs and groundwater downwind. They found PFOA contamination extending into undeveloped forest. Springs and seeps 8 kilometers—about five miles—downwind contained PFOA even though they were more than 300 meters higher in elevation than the factories.
Their conclusion was straightforward: industrial PFAS released into air can deposit on land and subsequently contaminate groundwater. (PubMed)
New Hampshire provides another important example. State enforcement against Saint-Gobain explicitly addressed PFAS air emissions that could contribute to exceedances of groundwater standards. EPA later described New Hampshire’s investigation as involving PFAS emitted to the air and subsequent contamination of drinking-water wells in surrounding communities. (NHDES)
Those cases do not prove that 3M’s Cottage Grove emissions contaminated Hastings.
They establish something more basic but important: the pathway Hastings describes is physically real.
What exactly is Hastings accusing 3M of doing?
Hastings operates municipal wells several miles southeast of 3M’s Cottage Grove facility, across the Mississippi River.
Its new lawsuit concerns five of them:
- Well 3
- Well 4
- Well 6
- Well 7
- Well 8
The complaint says 3M manufactured PFOA and PFOA-based products at Cottage Grove from 1947 until its phaseout in the early 2000s.
According to production records described in the complaint, 3M reported making about 2.522 million pounds of finished PFOA goods at Cottage Grove between 1976 and 1998 alone.
Hastings alleges that some PFOA escaped during manufacturing through stacks and other air-emission points, traveled southeast, deposited over the Hastings area and slowly migrated into groundwater.
The city is now building treatment infrastructure because PFOA concentrations in five of its six existing wells exceed the federal drinking-water standard. Hastings estimates that its three-treatment-plant program will cost about $68.9 million to design and construct. (City of Hastings)
EPA’s enforceable maximum contaminant level for PFOA remains 4 parts per trillion. As of August 2026, EPA has proposed an optional process that could give qualifying water systems until 2031 rather than 2029 to comply, but that extension has not yet replaced the existing rule. (US EPA)
Did 3M really estimate that 1,950 pounds of PFOA went into the air in 1997?
Yes—with an important qualification.
This number is not merely an assertion invented by Hastings’ lawyers.
A 2005 government health consultation reported:
3M estimated that approximately 1,950 pounds of PFOA compounds were released into the air from vent stacks at Cottage Grove in 1997.
The document said releases occurred during approximately 100 to 200 days that year and added that fugitive PFOA emissions in vapor and particulate form were also considered likely from activities such as drum loading, reactor sampling and drying. (Minnesota Department of Health)
But the wording needs to remain precise.
It does not establish that government inspectors directly measured exactly 1,950 pounds leaving a smokestack.
It was 3M’s estimate, subsequently reported by government health officials, and it referred to PFOA compounds released during 1997.
Nor is 1,950 pounds a lifetime total.
The importance of the number is that it independently confirms that historical Cottage Grove air releases were not simply hypothesized after contamination appeared in Hastings. Substantial PFOA air emissions were being discussed in government records decades ago.
A 2005 investigation was already asking whether Cottage Grove’s air emissions could reach groundwater
The historical record is unusually relevant to the new case.
In its 2005 Cottage Grove health consultation, the Minnesota Department of Health examined whether PFOA released into the atmosphere could leave the property, settle onto land and eventually enter groundwater.
It concluded that off-site aerial deposition followed by infiltration could be a groundwater-contamination pathway.
But one important detail has disappeared from some retellings of this history.
The old dispersion model was not actually a PFOA model
A 1991 air-dispersion model examined emissions from the area of Building 15, where PFC production occurred.
But the substance directly modeled was hydrogen fluoride, not PFOA.
That model showed hydrogen fluoride traveling beyond the facility boundary. Government scientists then reasoned that PFOA released from the same production area could also have traveled off-site—but explicitly acknowledged that PFOA and hydrogen fluoride have different physical properties. (Minnesota Department of Health)
That distinction is critical.
The old modeling supports:
“Air emissions from this production area could move off-site, and PFOA deposition was plausible.”
It does not support:
“A 1991 PFOA model demonstrated that PFOA traveled from Cottage Grove into Hastings wells.”
Those are different claims.
The new lawsuit says 3M has since done more relevant air analysis
Hastings’ complaint describes a 2025 3M air-emissions report that appears much more directly relevant.
According to the complaint, 3M ranked Cottage Grove operations according to their potential for PFAS air emissions and concluded that greater production generally corresponded with greater emission potential. The complaint says the report identified ECF-cell production as having relatively large air-emission potential and described shallow soils as capable of retaining decades of deposited PFOA.
Most importantly, Hastings says that report found a prevailing northwest-to-southeast wind pattern, placing the city’s wells downwind of Cottage Grove.
That could become important evidence.
But there is presently a verification limitation: the complaint quotes and characterizes the 2025 report without attaching it, and sherafy.com did not locate a public copy during this review.
Until the underlying report is available, we cannot independently determine exactly what was modeled, what time periods were used, whether actual historical PFOA emission rates were reconstructed, or whether the analysis calculated deposition specifically over Hastings.
For now, therefore, the correct formulation is:
Hastings says 3M’s 2025 analysis supports its wind-and-deposition theory.
Not:
3M has already proved that its PFOA landed on Hastings.
The groundwater evidence makes the case more interesting
The city’s argument does not rest entirely on wind direction.
Its complaint points to several additional patterns.
Hastings says Dakota County well sampling shows PFAS concentrations declining with depth, which it argues is consistent with contamination originating at the land surface and migrating downward.
It says PFAS profiles across Hastings are unusually similar, which the city argues better fits widespread atmospheric deposition than a collection of isolated spills.
It also identifies a monitoring well near Cottage Grove, MW-07, selected to represent an area without a known localized PFAS source, that allegedly contains many of the same PFAS found in Hastings.
Each observation can strengthen an atmospheric-deposition theory.
None, however, is uniquely diagnostic by itself.
For example, concentrations declining with depth are consistent with a surface source. That does not automatically establish what the surface source was.
The strongest case would come from several independent lines of evidence converging on the same explanation.
That is what Hastings is attempting to build.
The PFOA itself may contain another clue
The complaint says PFOA detected in the Hastings wells includes both linear and branched isomers.
An isomer is the same basic chemical formula arranged structurally in a different way.
Why does that matter?
Historically, 3M manufactured PFOA using electrochemical fluorination, or ECF. That process produces a mixture containing both linear and branched PFOA. Fluorotelomerization, another major manufacturing process, produces predominantly linear material. CDC describes this manufacturing distinction, and environmental researchers have long used PFOA isomer patterns as clues about potential sources. (CDC)
Hastings alleges that this pattern ties its PFOA to material manufactured by 3M.
It is potentially meaningful evidence—but not a molecular serial number.
A 2026 Analytical Chemistry study examining PFOA source fingerprinting emphasized an important limitation: isomer patterns can help distinguish different manufacturing processes, but available evidence does not show that isomer ratios alone can reliably distinguish two different sources using the same manufacturing method. (ACS Publications)
That leads to one of the most important distinctions in this case.
Source attribution is not the same as pathway attribution
Suppose future evidence establishes with high confidence that the PFOA originated with 3M.
A second question would still remain:
How did it reach Hastings?
Possibilities could theoretically include:
- atmospheric deposition;
- groundwater migration;
- surface-water transport;
- wastewater;
- historical disposal;
- some combination of routes.
Chemical fingerprinting can help answer who made it.
Meteorology, soil chemistry and hydrogeology are needed to answer how it got there.
The lawsuit ultimately needs to connect both.
There is a strange way 3M’s historical groundwater argument may help Hastings’ air-pollution theory
For years, 3M argued that groundwater underneath Cottage Grove was unlikely to migrate freely away from the facility.
That is because high-capacity production wells pumped enormous quantities of groundwater from beneath the property, creating what hydrogeologists call a cone of depression—essentially drawing groundwater toward the pumping wells.
A 2003 3M submission to EPA said this pumping created a persistent cone of depression that effectively limited groundwater movement from the developed portion of the site toward the Mississippi River. (Minnesota Attorney General)
The 2005 health consultation largely agreed that most groundwater beneath the developed portion of the 865-acre site appeared to be captured by the plant’s production wells, though it identified uncertainties and exceptions. (Minnesota Department of Health)
That produces an interesting evidentiary problem.
If contamination in Hastings originated at Cottage Grove, but direct groundwater movement from underneath the plant toward Hastings is difficult to establish, another pathway has to explain how it crossed the distance.
Hastings says that pathway was the atmosphere.
This does not prove the city’s argument. But logically, evidence weakening one competing pathway can make another otherwise well-supported pathway more plausible.
PFBA and TFSI may act as additional tracers
Hastings also points to two other chemicals associated with Cottage Grove: PFBA and TFSI.
The city is not seeking damages for those chemicals in this lawsuit. It is suing over PFOA.
Instead, it uses them as potential tracers.
According to the complaint, 3M manufactured substantial quantities of PFBA products at Cottage Grove during the PFOA-production era, and PFBA is also detected in Hastings.
The complaint also discusses TFSI, a chemical associated with an electrolyte product manufactured at Cottage Grove beginning in the early 1990s. Hastings argues that finding TFSI at multiple Hastings locations makes certain older local waste sites less convincing as explanations because some stopped accepting waste decades before 3M began producing TFSI.
TFSI is especially important because Minnesota regulators have already used it in a separate investigation involving another Hastings well.
What about Hastings Well 5? Minnesota has already linked that well to 3M
This is an easy fact to misunderstand.
Well 5 is not one of the five wells in the new lawsuit.
Minnesota’s 3M PFAS Settlement co-trustees previously determined that treatment of Well 5 was eligible for settlement funding after regulators found a connection between its PFAS contamination and the Cottage Grove facility.
Their evidence included:
- TFSI detected both at Cottage Grove and in Well 5;
- a major fault extending from the Mississippi River close to Well 5;
- isotope testing indicating that pumping from Well 5 draws in some surface water. (Minnesota 3M PFAS Settlement)
That is materially different from the atmospheric theory Hastings is advancing for Wells 3, 4, 6, 7 and 8.
The distinction actually illustrates how complicated PFAS transport can be.
The same industrial facility can potentially contribute contamination through different environmental pathways.
The fact that Minnesota has linked Well 5 to Cottage Grove therefore does not automatically establish the city’s case concerning the other five wells.
What would make the smokestack theory substantially stronger?
The lawsuit already identifies a coherent chain of circumstantial evidence. But several types of evidence could transform a plausible case into a much stronger attribution.
The most useful would be a historical PFOA-specific atmospheric reconstruction combining:
- actual or defensibly estimated annual PFOA emissions;
- stack locations and release characteristics;
- historical hourly wind direction and speed;
- precipitation;
- modeled wet and dry deposition;
- soil sampling along predicted deposition gradients;
- vertical PFAS profiles through soil and groundwater;
- chemical and isomer fingerprints;
- groundwater recharge and municipal-well capture modeling.
The result should answer a quantitative question:
Could the amount of PFOA reasonably deposited over the Hastings recharge area explain the concentrations subsequently measured in its wells?
That would be much more powerful than merely drawing an arrow from northwest to southeast on a map.
Likewise, if predicted historical deposition were concentrated elsewhere, soil cores failed to show the expected pattern, or another transport route reproduced the observed groundwater chemistry substantially better, the atmospheric theory would weaken.
That is how the claim should ultimately be tested.
What has 3M said?
In a statement provided to FOX 9 after the lawsuit was filed, 3M called Hastings’ decision to litigate “unfortunate.”
The company pointed to its 2018 commitment of $850 million to address PFAS contamination in Minnesota, its multibillion-dollar national public-water settlement and its completion of a global PFAS-manufacturing exit by the end of 2025. It said it remains willing to discuss legitimate concerns with Hastings. (FOX 9 Minneapolis-St. Paul)
That statement did not address the complaint’s atmospheric-deposition evidence point by point.
The complaint also cites an August 2024 statement in which 3M said that a connection between PFOA detected in Hastings and the Cottage Grove facility had not been sufficiently established.
That is ultimately the central factual dispute.
So, did PFOA from 3M smokestacks contaminate Hastings’ drinking-water wells?
There are really three different questions, and they currently have three different answers.
| Question | Best current answer |
|---|---|
| Can airborne PFOA travel downwind and deposit onto land? | Yes. Established science. |
| Can deposited PFOA migrate through soil into groundwater and wells? | Yes. Established and documented elsewhere. |
| Did historical 3M Cottage Grove air emissions cause the PFOA in Hastings Wells 3, 4, 6, 7 and 8? | Plausible and supported by multiple allegations and clues, but not yet established. |
Several facts make Hastings’ theory worthy of serious consideration.
Historical Cottage Grove PFOA air emissions are documented. The federal government was examining off-site deposition from this plant two decades ago. The air-to-groundwater pathway has since been demonstrated elsewhere. Hastings lies in the direction the complaint says 3M identified as prevailing downwind. And the city points to depth patterns, PFAS profiles, isomer chemistry and other Cottage Grove-associated compounds as corroborating evidence.
But causation requires more than showing that something could have happened.
The unresolved issue is quantitative and forensic:
How much PFOA left Cottage Grove through the air, where did it actually land, how much migrated into the aquifer, and does that transport history best explain the contamination now found in these five wells?
That question has not yet been conclusively answered.
What can be answered is the question behind the surprising headline:
Yes—a chemical released from an industrial smokestack can ultimately end up in a drinking-water well miles away without ever being directly dumped into that well’s groundwater.
For PFOA, that pathway is no longer hypothetical.
References and Further Reading
Hastings lawsuit and drinking-water records
City of Hastings — City Files Lawsuit Against 3M — The city’s announcement of the August 26, 2026 lawsuit and gateway to the underlying filing.
City of Hastings v. 3M Company — Full Complaint — Primary source for the city’s allegations concerning historical emissions, wind direction, groundwater chemistry, isomers and other proposed tracers.
City of Hastings — Municipal Well Treatment and PFAS Testing — Current city information on well testing and treatment needs.
City of Hastings — PFAS Treatment Plans — Treatment-plant plans, technologies, timeline and estimated construction cost.
Cottage Grove historical evidence
Minnesota Department of Health / ATSDR — 3M Cottage Grove Health Consultation — Crucial 2005 government assessment documenting 3M’s 1997 air-emission estimate and discussing aerial deposition as a possible groundwater pathway.
Minnesota Attorney General Exhibit — 3M Cottage Grove Groundwater Submission to EPA — Includes 3M’s historical description of pumping-induced groundwater capture beneath the Cottage Grove facility.
Independent atmospheric PFAS science
EPA — Simulating PFAS Fate and Transport in Air with CMAQ — EPA overview of atmospheric PFAS transport, deposition and possible surface- and groundwater contamination.
D’Ambro et al. — Characterizing PFAS Air Emissions, Transport and Deposition From a Fluoropolymer Manufacturing Facility — EPA-led peer-reviewed modeling study examining atmospheric transport and deposition from an industrial source.
Perkins et al. — PFAS Soil and Groundwater Contamination via Industrial Airborne Emission and Land Deposition — Peer-reviewed field evidence from Vermont and New York finding PFOA in soil and groundwater several miles downwind of industrial sources.
Chemical fingerprinting
CDC — Calculation of PFOS and PFOA as Sum of Isomers — Explains the relationship between historical manufacturing processes and linear/branched PFAS isomers.
Analytical Chemistry — Source Fingerprinting of PFOA Using Isomers and Stable Isotope Ratios — Useful recent research explaining both the potential and limitations of PFOA isomer patterns for identifying sources.
Hastings Well 5
Minnesota 3M PFAS Settlement — Hastings and Settlement Eligibility — Explains the separate evidence connecting Hastings Well 5 to Cottage Grove, including TFSI, geology and isotope analysis.
Current federal drinking-water standard
EPA — Final PFAS National Primary Drinking Water Regulation — Current federal PFOA standard and regulatory status.
EPA — Proposed PFOA and PFOS Compliance Extension Rule — Current 2026 proposal concerning possible compliance extensions to 2031.
Editorial currency note: The Hastings litigation was filed August 26, 2026, and remains in its earliest stage. The allegations have not been adjudicated. EPA’s 4-ppt PFOA drinking-water MCL remains in force, while the agency’s proposed compliance-extension process was not final as of August 31, 2026. This article should be updated when 3M files its substantive response, when the 2025 Cottage Grove air-emissions report becomes publicly available, or when additional expert modeling and groundwater data enter the court record.
