Commingled PFAS Contamination and the Limits of Disclaimer-Based Avoidance of Federal Officer Removal

Commentary on State of Maine v. 3M Company, No. 23‑1709 (1st Cir. Nov. 19, 2025)

I. Introduction

In State of Maine v. 3M Company, the United States Court of Appeals for the First Circuit confronted a sophisticated jurisdictional maneuver in nationwide PFAS litigation. The State of Maine sued 3M in state court for extensive environmental contamination from “forever chemicals” (PFAS), but deliberately split its claims into two cases:

an “AFFF Complaint” targeting PFAS contamination from 3M’s Aqueous Film Forming Foam (AFFF), much of which was manufactured under military specifications (MilSpec AFFF); and
a “non‑AFFF Complaint” purporting to seek recovery only for PFAS contamination not related to AFFF.

Maine added a disclaimer to the non‑AFFF complaint stating that it was “not seeking to recover through this Complaint any relief for contamination or injury related to Aqueous Film Forming Foam.” The clear strategic goal was to block 3M from removing the non‑AFFF case to federal court under the federal officer removal statute, 28 U.S.C. § 1442(a)(1), and thereby to keep at least one large PFAS case in state court.

The First Circuit held that this tactic failed. Once a defendant plausibly shows that PFAS contamination from MilSpec AFFF (for which it has a federal contractor defense) has commingled with other PFAS in the natural resources that the State seeks to remediate, the defendant has:

a “colorable” federal defense within the meaning of Mesa v. California, and
a sufficient “related to” nexus to federal acts under § 1442(a)(1).

A disclaimer that would force a state court to decide whether and to what extent PFAS contamination at a given site is attributable to federal‑directed conduct cannot defeat federal officer removal. The defendant is entitled to have those factual and legal issues decided in a federal forum.

This decision significantly strengthens federal officer removal in PFAS and other mass‑contamination cases, sharply limits plaintiffs’ use of disclaimers to avoid federal jurisdiction, and extends the First Circuit’s “disclaimer doctrine” first elaborated in Gov’t of Puerto Rico v. Express Scripts, Inc., 119 F.4th 174 (1st Cir. 2024).

II. Factual and Procedural Background

A. PFAS, AFFF, and MilSpec AFFF

PFAS (per‑ and polyfluoroalkyl substances) are highly persistent chemicals used in numerous industrial and consumer products. A key PFAS‑containing product is AFFF, a firefighting foam historically used to extinguish fuel fires, particularly at:

U.S. military installations, and
commercial airports complying with Federal Aviation Administration requirements for MilSpec‑compliant foam.

“MilSpec AFFF” refers to AFFF manufactured to military specifications imposed by the U.S. Department of Defense. 3M produced MilSpec AFFF under federal direction; this is the cornerstone of its assertion of the federal government contractor defense recognized in Boyle v. United Technologies Corp., 487 U.S. 500 (1988).

B. Maine’s Dual‑Complaint Strategy and Disclaimer

On March 29, 2023, Maine filed two nearly identical environmental suits in state court:

The AFFF Complaint – explicitly seeking recovery for PFAS contamination arising from 3M’s production and sale of AFFF, including MilSpec AFFF.
The non‑AFFF Complaint – purporting to seek recovery only for PFAS contamination not caused by AFFF, and containing the disclaimer:
“The State is not seeking to recover through this Complaint any relief for contamination or injury related to Aqueous Film Forming Foam [‘AFFF’ or ‘MilSpec AFFF’], a firefighting material that contains PFAS.”

The non‑AFFF Complaint nevertheless:

alleged that PFAS contamination was “ubiquitous” and “widespread” throughout Maine,
claimed injury to broad categories of “State natural resources and property,” including rivers, groundwater, fish, wildlife, soil, and sediment statewide, and
made clear that the complaint covered both existing and yet‑to‑be‑identified sites, far beyond the roughly 22 “example” locations listed.

Maine sought:

compensatory and punitive damages,
investigation, monitoring, and remediation costs, and
natural resource damage and restoration costs.

C. Removal and the District Court’s Remand

3M removed both cases to federal court under the federal officer removal statute, 28 U.S.C. § 1442(a)(1). Maine did not oppose removal of the AFFF case, which was then transferred into the AFFF multidistrict litigation in South Carolina (In re Aqueous Film‑Forming Foam Products Liability Litigation (MDL No. 2873)).

Maine did move to remand the non‑AFFF case, arguing that its disclaimer stripped 3M of any “colorable” federal defense, and therefore § 1442(a)(1) jurisdiction was lacking. The district court agreed, reasoning:

By disavowing any recovery “related to AFFF,” the State had made “no AFFF” part of its prima facie case for each site.
Thus, on remand, if the factfinder concluded that any contamination at a given site stemmed from AFFF, Maine would simply lose as to that site.
On this logic, the district court concluded that the federal contractor defense would “not be applicable” to the non‑AFFF lawsuit and remanded to state court.

D. Post‑Remand Developments and Additional Removal Notices

While the remand order was on appeal, discovery continued in state court. Maine’s interrogatory answers on August 12, 2025, expanded the case dramatically: the State identified 910 specific sites at issue, far beyond the 22 examples in the complaint.

3M then filed:

a second notice of removal (September 8, 2025) and
a supplemental removal petition (September 24, 2025),

to “preserve its right to a federal forum” based on the new facts. In these filings, 3M plausibly alleged that several of the newly listed sites were contaminated—at least in part—by PFAS from MilSpec AFFF used at nearby federal installations, including:

the Brunswick/Topsham Water District (BTWD), allegedly impacted by PFAS migrating from the former Naval Air Station Brunswick;
the Hawk Ridge Compost Facility and Juniper Ridge Landfill, which received sludge from a sewage district processing BTWD water;
the Androscoggin River, downstream from the naval station, where Maine claims damage to “fish fillet”; and
the Aroostook River, Little Madawaska River, and Penobscot River, downstream from Loring Air Force Base and the Maine Air National Guard Base in Bangor.

These developments reinforced 3M’s original contention: that PFAS from MilSpec AFFF had commingled with PFAS from other sources in many of the very resources Maine sought to recover for in its “non‑AFFF” case.

III. Summary of the First Circuit’s Decision

The First Circuit reversed the district court’s remand order and held that:

3M satisfied all three requirements for federal officer removal under 28 U.S.C. § 1442(a)(1).
- Acting under: Maine conceded that 3M acted under federal authority in producing MilSpec AFFF.
- Nexus: Maine’s sweeping non‑AFFF action is “related to” 3M’s federally directed AFFF conduct because 3M plausibly alleged that PFAS from MilSpec AFFF has commingled with the PFAS contamination of the resources at issue.
- Colorable federal defense: 3M has at least a colorable government contractor defense under Boyle with respect to contamination attributable to MilSpec AFFF.
Maine’s disclaimer does not defeat federal officer removal.
- The disclaimer is not an effective “express disclaimer” under the First Circuit’s “disclaimer doctrine” in Gov’t of Puerto Rico v. Express Scripts.
- It is ambiguous and does not clearly carve out factual bases (by specific time or location) such that no injury could have been caused under federal direction.
- It would require a state court to determine the very nexus between the alleged conduct and federal authority that § 1442(a)(1) entrusts to federal courts.
3M is entitled to a federal forum to litigate the scope and validity of its federal contractor defense.
- One of the “most important reasons” for federal officer removal is to ensure that the validity of federal immunity or contractor defenses is adjudicated in federal court.
- Maine’s attempt to have “two courts answer the same questions” about PFAS sources and apportionment—state court in the non‑AFFF case and federal court in the AFFF MDL—must fail.

The court remanded with instructions that the district court:

order the non‑AFFF case returned from state court,
resume jurisdiction, and
handle any motion to transfer the case (e.g., to MDL No. 2873 in the District of South Carolina) in the usual way.

IV. Detailed Analysis

A. The Doctrinal Framework

1. Federal Officer Removal under 28 U.S.C. § 1442(a)(1)

Section 1442(a)(1) allows removal of a state‑court action brought against:

“The United States or any agency thereof or any officer (or any person acting under that officer) … for or relating to any act under color of such office….”

Three requirements, drawn from Mesa v. California, 489 U.S. 121 (1989), and Jefferson County v. Acker, 527 U.S. 423 (1999), govern:

“Acting under” – the defendant must have been “acting under” a federal officer in performing the challenged conduct (e.g., as a government contractor executing federal directives).
Nexus (“for or relating to”) – the suit must be “for or relating to” acts under color of office; after a 2011 statutory amendment, this is a broad “related to” standard, not a strict causal requirement.
Colorable federal defense – the notice of removal must assert a federal defense that is at least “colorable,” i.e., not “wholly insubstantial and frivolous” or “immaterial and made solely for the purpose of obtaining jurisdiction.”

Mesa clarified that the colorable defense itself supplies the federal question necessary for Article III jurisdiction, overriding the normal “well‑pleaded complaint rule” that looks only to the plaintiff’s complaint.

Acker added two critical interpretive principles:

Courts must credit the removing party’s “theory of the case” when assessing nexus and colorable defense.
The defense need not be “clearly sustainable” on the merits; imposing such a high threshold “would defeat the purpose of the removal statute.”

2. The 2011 Amendment and the “Related To” Nexus Standard: Moore v. Electric Boat

Before 2011, § 1442(a)(1) covered suits “for any act under color of [federal] office,” which several courts had construed as demanding a fairly tight causal connection. The Removal Clarification Act of 2011 broadened the language to “for or relating to any act under color of such office.”

In Moore v. Electric Boat Corp., 25 F.4th 30 (1st Cir. 2022), the First Circuit held:

The First Circuit’s nexus standard “is not a causal requirement and is not to be understood as anything more than a ‘related to’ nexus.”
Applying a “causal link” standard is “far narrower than the proper standard under § 1442(a)(1), as amended.”

Thus, where claims “relate to” conduct performed under federal direction—even if that conduct is only part of the broader factual matrix—removal is permitted.

3. The “Disclaimer Doctrine”: Gov’t of Puerto Rico v. Express Scripts

In Gov’t of Puerto Rico v. Express Scripts, Inc., the First Circuit confronted a plaintiff (Puerto Rico) that tried to avoid federal officer removal of an insulin pricing lawsuit by inserting a disclaimer:

“[The Commonwealth does] not seek relief relating to any federal program … or any contract related to a federal program.”

The defendant Caremark, a pharmacy benefit manager, argued that it negotiated drug rebates for both federal (under FEHBA) and private clients in a single blended process. It raised a FEHBA preemption defense and sought § 1442 removal.

The First Circuit held:

Courts must first credit the defendant’s theory of the case and then ask whether the plaintiff’s disclaimer truly eliminates any basis for removal.
Some disclaimers are “express disclaimers” that can defeat removal—e.g., those that clearly carve out claims based on specific periods, locations, or factual scenarios such that no alleged injury could have resulted from federally directed conduct.
Other disclaimers are merely “artful pleading” and “are never credited” when they:
- require a state court to determine the nexus “between the charged conduct and federal authority,”
- force federal contractors to prove in state court that they were acting under federal direction, or
- nominally disavow claims based on federal conduct while still seeking recovery for that very conduct.

Because Puerto Rico’s disclaimer would have required a state court to decide, at the merits stage, whether the negotiations at issue were “federal” or “nonfederal,” it could not bar § 1442 removal. Caremark was entitled to have a federal court adjudicate its preemption defense.

4. The Government Contractor Defense: Boyle v. United Technologies

In Boyle, the Supreme Court recognized a federal common‑law “government contractor defense” that preempts certain state tort claims when:

the United States approved reasonably precise specifications;
the equipment or product conformed to those specifications; and
the contractor warned the United States about dangers in the use of the equipment that were known to the contractor but not to the United States.

In PFAS/AFFF litigation, contractors like 3M argue that:

the military dictated specifications for MilSpec AFFF,
the product conformeds to those specifications, and
to the extent there were undisclosed risks, these were adequately disclosed to the government.

This defense—if applicable—can bar liability for design and failure‑to‑warn claims based on MilSpec AFFF.

B. Application to State of Maine v. 3M

1. “Acting Under” a Federal Officer

Maine did not dispute that 3M “acted under” a federal officer when it produced MilSpec AFFF for the U.S. military and to meet federal requirements (e.g., FAA requirements for certain airports). That element of § 1442(a)(1) was therefore satisfied and was not at issue on appeal.

2. The Nexus Requirement and Commingled Contamination

The key question was whether Maine’s non‑AFFF lawsuit was “for or relating to” acts taken under color of federal office—i.e., 3M’s production and provision of MilSpec AFFF.

3M’s theory (which the court was required to credit under Acker and Gov’t of Puerto Rico) was that:

Maine’s non‑AFFF Complaint seeks to recover for PFAS contamination of statewide natural resources—rivers, groundwater, wildlife, fish, soil, and sediment—without geographical or temporal limits, and including as‑yet‑undiscovered sites.
PFAS is highly mobile and “ubiquitous”; contamination migrates through air, water, soil, and especially via land application of PFAS‑laden sludge and septage.
MilSpec AFFF was used at numerous federal facilities in Maine (naval air stations, Air Force bases, National Guard bases) and PFAS from this AFFF has migrated offsite and commingled with PFAS from other sources in the same environmental media.

The court accepted this as a plausible, not frivolous, account. 3M bolstered its position with:

allegations of AFFF use at five identified military facilities in Maine,
environmental reports and Maine DEP data suggesting that PFAS from those facilities migrated offsite into rivers, water systems, sludge, and landfills, and
evidence that some of the 910 sites Maine itself put at issue (e.g., BTWD, Hawk Ridge, Juniper Ridge, several rivers) plausibly bear contamination traceable to MilSpec AFFF.

Under Moore’s broad “related to” standard, it was enough that Maine’s statewide claims bear a substantial relation to the alleged MilSpec AFFF contamination. The nexus requirement was satisfied.

Notably, Maine did not argue on appeal that, assuming a colorable federal defense, the nexus requirement was still lacking. The First Circuit treated any such claim as waived and, in any event, meritless.

3. The Colorable Federal Defense

The critical dispute was whether 3M had a “colorable federal defense” in the non‑AFFF case given Maine’s disclaimer. The First Circuit held that it did.

3M claimed a government contractor defense (under Boyle) as to PFAS contamination attributable to MilSpec AFFF. Where contamination at a site is a mixture of:

PFAS from MilSpec AFFF (federally directed) and
PFAS from non‑AFFF sources (nonfederal products),

3M would argue that it cannot be held liable—at least to the extent contamination stems from MilSpec AFFF—because of Boyle.

Maine, however, structured its theory of liability to require the State to prove, as part of its case‑in‑chief for each site, that the PFAS contamination was not attributable to AFFF at all. It argued on appeal:

“If the State fails to prove that the PFAS contamination came from a non‑AFFF source at a particular location, then it cannot recover for that location.”

From this, the State and the district court reasoned: if the presence of AFFF contamination at a site simply causes the State to lose its claim for that site (because it failed to prove non‑AFFF causation), then there is no occasion to litigate any federal contractor defense. Thus, 3M supposedly lacks any colorable federal defense in the non‑AFFF case.

The First Circuit rejected that logic. It emphasized:

3M’s way of defeating the State’s claim at particular sites is precisely by showing that contamination is attributable, “in whole or in part,” to MilSpec AFFF.
Whenever 3M “attempts to show … that PFAS contamination of particular sites … was caused in whole or in part by MilSpec AFFF,” 3M will “necessarily raise” its government contractor defense.
Whether a site’s PFAS contamination is 0% AFFF, or some percentage > 0% AFFF, is an allocation or source‑apportionment question, and Maine’s attempted distinction between “attribution” and “allocation” does not change the analysis.

Under the First Circuit’s standard, a federal defense is colorable unless it is “immaterial and made solely for the purpose of obtaining jurisdiction” or “wholly insubstantial and frivolous.” 3M’s Boyle defense as to MilSpec AFFF plainly cleared that low threshold.

4. Why Maine’s Disclaimer Fails Under the Disclaimer Doctrine

The First Circuit evaluated Maine’s disclaimer through the lens of Gov’t of Puerto Rico’s “disclaimer doctrine.”

To be an effective express disclaimer that defeats removal, the disclaimer must:

“clearly carve[] out certain factual bases, whether by time span or location, such that any alleged injury could not have happened under the direction of a federal officer.”

Maine’s disclaimer does not meet that standard for several reasons:

It is not tied to specific times or locations.
The State did not:
- limit its non‑AFFF suit to specific facilities known to involve only non‑AFFF PFAS, or
- exclude from the case any sites plausibly influenced by AFFF migration.
Instead, it sought damages for PFAS injury to natural resources statewide, including rivers and fish that could migrate across AFFF and non‑AFFF zones.
It is substantively ambiguous.
The complaint attempts to disclaim recovery for “contamination and injury related to AFFF,” but it is unclear:
- What “related to” means in the context of commingled contamination, and
- Whether any presence of AFFF at a site disqualifies the site, or only AFFF‑dominant contamination, or something else.
The First Circuit explicitly held that the phrase “contamination and injury related to AFFF” is ambiguous and thus not the type of unambiguous, express disclaimer that Gov’t of Puerto Rico contemplates.
It would force a state court to resolve the federal nexus question.
Most importantly, Maine’s theory would require the state court, on the merits, to decide:
- whether contamination at each site is attributable to AFFF (and thus federally directed conduct), and
- if so, whether the State’s suit can or cannot proceed as to that site.
This is exactly the type of disclaimer that Gov’t of Puerto Rico held “is never credited” because it leaves the determination of the nexus “between the charged conduct and federal authority” to the state court, contrary to the purpose of § 1442(a)(1).

In other words, the disclaimer is a form of artful pleading, not a true narrowing of the factual bases of the claim. It does not preclude removal.

5. The Right to a Federal Forum

A central theme in the First Circuit’s reasoning is the insistence that § 1442(a)(1) exists to:

protect federal interests and operations, and
ensure that federal defenses—especially immunity and contractor defenses—are adjudicated in a federal forum.

Citing Acker and Willingham v. Morgan, 395 U.S. 402 (1969), the court emphasized:

“[O]ne of the most important reasons for removal is to have the validity of the defense of official immunity tried in a federal court.” (Acker, quoting Willingham).

Allowing Maine’s disclaimer to block removal would:

force 3M to litigate factual disputes about AFFF‑related contamination and the scope of its federal defense in state court, and
permit state and federal courts to issue potentially conflicting findings about the same sources of PFAS contamination in overlapping natural resources.

The First Circuit held that § 1442(a)(1) guarantees 3M “the protection of a federal forum in which to resolve these disputes” and “the opportunity to present [its] version of the facts” to a federal judge. Maine cannot use a disclaimer to undermine that statutory right.

C. Comparative Case Law and Circuit Dialogue

1. Alignment with the Fourth Circuit: Maryland v. 3M Co.

The First Circuit found strong support in the Fourth Circuit’s decision in Maryland v. 3M Co., 130 F.4th 380 (4th Cir. 2025), which involved nearly identical dual‑complaint strategies by Maryland and South Carolina (one AFFF case and one “non‑AFFF” case).

The Fourth Circuit:

also relied on Gov’t of Puerto Rico’s disclaimer analysis,
held that disclaimers that do not carve out commingled sites cannot defeat removal, and
emphasized that state courts cannot be tasked with making the AFFF/non‑AFFF apportionment decisions that go to the heart of the federal nexus question.

The First Circuit’s opinion in Maine v. 3M explicitly cites Maryland as reinforcing its reasoning, particularly as to commingled contamination and the impropriety of remitting apportionment issues to state courts as a way of denying removal.

2. Distinguishing the Seventh Circuit: People ex rel. Raoul v. 3M Co.

Maine relied heavily on the Seventh Circuit’s decision in People ex rel. Raoul v. 3M Co., 111 F.4th 846 (7th Cir. 2024), where Illinois succeeded in keeping a PFAS suit in state court.

The First Circuit distinguished Raoul on three grounds:

Factual narrowness of the Illinois case.
Illinois’s suit was narrowly focused on PFAS contamination allegedly arising from non‑AFFF PFAS production at a single facility, quite unlike Maine’s sweeping statewide natural resources case.
Recognition that commingling can support a colorable defense.
Even the Seventh Circuit acknowledged that 3M would have a colorable federal defense in cases involving commingled contamination requiring apportionment between AFFF and non‑AFFF PFAS.
Divergent approach to who decides the nexus question.
To the extent Raoul might be read to allow a state court to decide whether there is any AFFF contamination (and thus any nexus to federal authority) even when the defendant has plausibly alleged commingling, that reading conflicts with the First Circuit’s rule in Gov’t of Puerto Rico, which bars leaving that nexus determination to a state tribunal in the face of a colorable federal defense.

3. Distinguishing the Ninth Circuit: California ex rel. Harrison v. Express Scripts, Inc.

Maine also cited the Ninth Circuit’s decision in California ex rel. Harrison v. Express Scripts, Inc., No. 24‑1972, 2025 WL 2586648 (9th Cir. Sept. 8, 2025), an opioid‑related case where disclaimers about federal programs were held sufficient to defeat federal officer removal.

The First Circuit identified key distinctions:

Different factual context. Harrison involved alleged opioid‑related misconduct, not PFAS commingling and migration.
The Ninth Circuit itself highlighted PFAS cases as “unique.” Harrison observed that PFAS cases like Maryland involve “unique facts” in which the source of the contaminant is difficult to identify due to commingling and environmental migration.
Conflict regarding apportionment decisions. Harrison upheld remand even where the state court would need to calculate proportions of harm attributable to federal versus nonfederal sources. The First Circuit, following Gov’t of Puerto Rico, explicitly rejects that approach: artful pleadings that shift nexus and apportionment issues to state courts cannot defeat removal.

V. Complex Concepts Simplified

1. What Is Federal Officer Removal?

Federal officer removal allows certain defendants to move cases from state to federal court when they are sued for conduct undertaken in connection with federal duties. It covers:

federal officers themselves, and
private entities “acting under” federal direction (e.g., government contractors).

The core idea: if a contractor is being sued because of what it did to help the federal government carry out its responsibilities, it should be able to defend itself in a federal forum and assert federal defenses.

2. What Is a “Colorable” Federal Defense?

“Colorable” does not mean “certain to win.” It means:

The defense is not frivolous.
There are plausible facts and legal arguments supporting it.

A contractor invoking § 1442 does not need to prove its defense at the removal stage; it only needs to show that the defense is substantial enough to warrant being heard in federal court.

3. What Is the Government Contractor Defense?

Under Boyle, when a contractor makes a product to federal specifications, it can sometimes avoid liability for design defects or failure to warn if:

the government approved reasonably detailed specifications,
the contractor followed them, and
the contractor told the government about any special dangers it knew about that the government did not know.

The rationale is that design decisions in such settings are effectively government decisions; state tort law should not second‑guess those federal policy choices.

4. What Is “Commingled” Contamination?

“Commingled” contamination refers to situations where pollutants from multiple sources—here, PFAS from MilSpec AFFF and PFAS from other products—become mixed together in the environment (e.g., in the same groundwater plume, river, or fish population) such that:

the total contamination at a site is a blend of federal and nonfederal sources, and
it can be difficult or impossible to separate which portion comes from which source.

In the PFAS litigation context, commingling creates complex factual questions about:

who is responsible for what share of the harm, and
whether a contractor’s federal defenses apply to all or part of the claimed damages.

5. Disclaimers vs. Artful Pleading

Plaintiffs sometimes try to restrict their claims to avoid federal jurisdiction by “disclaiming” certain theories or categories of relief. The First Circuit distinguishes:

Express Disclaimers – clear, unambiguous statements that truly narrow the case (e.g., “We seek no damages for acts occurring before January 1, 2015,” or “We seek only damages arising from Facility X, not Facility Y.”). These can defeat removal if they eliminate any possible nexus to federal authority.
Artful Pleading Disclaimers – statements that, in form, disavow certain claims, but in substance:
- leave the factual overlap untouched, or
- require the state court to answer the key federal nexus questions.
These cannot defeat removal.

In Maine v. 3M, the disclaimer was artful rather than express: it purported to exclude AFFF‑related contamination but, in practice, demanded that a state court decide which contamination was AFFF‑related and which was not, even where AFFF and non‑AFFF sources were plausibly intertwined.

VI. Impact and Future Implications

1. Effects on PFAS and AFFF Litigation

This decision has immediate consequences for ongoing PFAS litigation, especially where:

states sue over widespread contamination of natural resources,
defendants have produced MilSpec AFFF or other federally directed PFAS products, and
contamination is plausibly commingled.

Key implications include:

More PFAS cases in federal court. States and other plaintiffs cannot reliably keep broad PFAS cases in state courts by carving out “AFFF” claims in a separate lawsuit while still seeking damages for resources plausibly impacted by MilSpec AFFF.
Increased funneling into MDL 2873. Non‑AFFF suits that are effectively “PFAS‑everywhere” actions may now be removed and then transferred to the existing AFFF multidistrict litigation in South Carolina, concentrating judicial management and settlement negotiations.
Strategic shift for plaintiffs. States may need to:
- either accept federal forums (and MDL coordination) for large‑scale PFAS claims, or
- carefully limit suits—by site, timeframe, and source—to contexts where commingling with AFFF is genuinely implausible.

2. Broader Lessons for Mass Torts and Environmental Cases

Beyond PFAS, the decision sends a message in other mass tort and environmental contexts:

Where contamination or harm results from a mix of federal and non‑federal sources, plaintiffs cannot use disclaimers to keep federal‑related issues out of federal court.
Defendants with plausible federal contractor or preemption defenses should aggressively develop factual records (e.g., about commingling, joint operations, or blended negotiations) to support § 1442 removal.
Courts will look behind the labels in complaints and disclaimers to assess the underlying factual overlap and federal nexus.

3. Federalism and Separation of Powers Considerations

The decision underscores a robust view of federal interests in:

protecting federal contractors facing liability for carrying out federal directives, and
ensuring that disputes about the scope of federal immunity and federal defenses are resolved in federal courts.

While states retain broad authority to protect their environments and natural resources, they cannot structure litigation to effectively nullify congressionally granted rights of removal and federal adjudication for federal contractors.

VII. Conclusion: Key Takeaways

State of Maine v. 3M Company establishes and reinforces several important principles:

Commingled contamination creates a “related to” nexus. When PFAS from MilSpec AFFF plausibly commingles with other PFAS in the resources a state sues over, the resulting claims are “related to” acts taken under color of federal office.
Government contractor defenses in such cases are colorable. A contractor like 3M, facing tort claims arising from allegedly commingled contamination, has at least a colorable Boyle defense as to the MilSpec AFFF component.
Disclaimers have limits. Plaintiffs cannot defeat federal officer removal with disclaimers that:
- lack clear, factual carve‑outs (by time or location),
- are ambiguous in scope, or
- would require state courts to adjudicate the very federal nexus and apportionment issues that § 1442 is designed to move into federal court.
Federal forums are guaranteed for federal defenses. One of the central purposes of § 1442(a)(1) is to ensure that the validity of federal immunity and contractor defenses is determined in a federal forum, not sidestepped through creative pleading.

In the broader legal landscape, Maine v. 3M solidifies the First Circuit’s expansive reading of federal officer removal in complex, fact‑intensive cases where federal and non‑federal conduct are intertwined. It will likely channel many large‑scale PFAS suits into federal court and MDL structures and will stand as a leading precedent on the limits of disclaimer‑based strategies to avoid federal jurisdiction.

Commingled PFAS Contamination and the Limits of Disclaimer-Based Avoidance of Federal Officer Removal: Commentary on State of Maine v. 3M Company