Breaking Coverage Case—Duty to Defend Owed for PFAS Claims
Jes Alexander
|September 26, 2025
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One of the emerging exposures for companies is the rise of per- and polyfluoroalkyl substances (PFAS) claims. Courts are being asked to decide whether general liability policies cover these massive nationwide claims. Their answers hinge, as they almost always do, on the precise policy language at issue.
To date, only a handful of court cases have addressed coverage for PFAS claims. Recently, a case from New York was decided that analyzed coverage for an airport where PFAS contamination was alleged. Read below for a full summary of this crucial case for liability insurers.
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An Airport Accused of PFAS Contamination Seeks Liability Coverage Despite a Pollution Exclusion
A town in New York operated the Adirondack Regional Airport (the "Airport"). In 2021, the New York State Department of Environmental Conservation (NYSDEC) sent the town a letter identifying it as a potentially responsible party for PFAS contamination at the airport. The contamination originated from the historic use of aqueous film-forming foam (AFFF) in firefighting training exercises, a common practice at airports nationwide.
The NYSDEC requested that the town conduct a site investigation and remediation under New York's environmental conservation laws. The "[l]etter did not refer to any alleged PFAS contamination at the site caused by or resulting in a crash fire explosion or collision or a recorded in-flight emergency causing abnormal aircraft operation."
Eventually, the NYSDEC issued a Superfund Site Classification Notice (the "Notice"), which stated as follows:
[The Airport] presents a significant threat to public health and/or the environment for the following reason(s): Per- and polyfluoralkyl substances (PFAS) have been detected at elevated levels in groundwater and surface water at the airport with perfluorooctanoic acid (PFOA) greater than 18,000 parts per trillion (ppt) and perfluorooctane sulfonic acid (PFOS) greater than 950 ppt.
Actions are needed to identify the source of this contamination, to define the nature and extent of contamination in groundwater and other environmental media, and to evaluate and address potential exposures.
The town notified its liability insurer, ACE, which issued an airport owners and operators general liability policy with a pollution liability endorsement. Initially, it agreed to defend under a full reservation of rights based on the policy's pollution exclusion and "Combined Claims" clause. Those provisions stated as follows:
A. Noise and pollution and other perils.
This policy does not cover claims directly or indirectly occasioned by, happening through or in consequence of:
(a) noise (whether audible to the human ear or not), vibration, sonic boom and any phenomena associated therewith,
(b) pollution and contamination of any kind whatsoever,
(c) electrical and electromagnetic interference,
(d) interference with the use of property; unless caused by or resulting in a crash fire explosion or collision or a recorded in-flight emergency causing abnormal aircraft operation.
unless caused by or resulting in a crash fire explosion or collision or a recorded in-flight emergency causing abnormal aircraft operation.
With respect to any provision in the policy concerning our duty to investigate or defend claims, such provision shall not apply and we shall not be required to defend:
(a) claims excluded by Paragraph 1; or
(b) a claim or claims covered by the policy when combined with any claims excluded by Paragraph 1 (referred to below as "Combined Claims").
In respect of any Combined Claims, we shall (subject to proof of loss and the LIMITS OF INSURANCE) reimburse you for that portion of the following items which may be allocated to the claims covered by the policy:
(i) damages awarded against any insured; and
(ii) defense fees and expenses incurred by any insured.…
Source: ACE USA, Airport Owners and Operators General Liability Policy (
AAP 202-NY (11-99)), at page 11 of 23.
"Combined Claims" was defined as "a claim or claims covered by the policy when combined with any claims excluded by Paragraph 1 [of the Pollution exclusion]."
Another insurer, Westchester, issued a virtually identical policy during a different policy period. Significantly, it contained the same pollution exclusion.
Eventually, the town entered into a "final Order on Consent and Administrative Settlement with NYSDEC relative to the Site." The order stated that "Contamination at the Site appears to be the result of [AFFF] spilled or used for training, responding to plane crashes, and/or for other purposes at the Site."
ACE and Westchester (the "insurers") subsequently advised the town that it would no longer defend them based on the policy's pollution exclusion. ACE stated that, "[b]ecause the NYSDEC Claim involves pollution or contamination, the Insurers have no duty to defend the claim, but only a potential duty to reimburse the Town for defense fees and expenses and damages, if any, properly allocable to pollution or contamination caused by a plane crash, fire, explosion, collision, or in-flight emergency." Prior to this letter, they "paid approximately $1.5 million in defense costs on behalf of the Town for the NYSDEC claim."
A coverage lawsuit was filed in a New York federal district court.
The New York Court Rules a Duty to Defend Exists
In Town of Harrietstown v. Westchester Fire Ins. Co., No. 8:24-CV-1184 (N.D.N.Y. Aug. 18, 2025), the New York federal district court held that the liability insurers owed a duty to defend the underlying suit alleging PFAS contamination. In reaching this result, the court analyzed whether the pollution exclusion barred coverage. The pollution exclusion stated that the policies did "not cover claims directly or indirectly occasioned by, happening through or in consequence of … pollution and contamination of any kind whatsoever." However, the exclusion contained a carve-out that restored coverage for five types of airport events that came within the exception: a crash, fire, explosion, collision, or in-flight emergency causing abnormal aircraft operation.
The insurers argued that this exclusion barred coverage, despite the existence of the carve-outs. The court rejected this argument and held as follows:
The exception does not state that is applies only if the pollution is caused "in part by" or "aggravated by" or "contributed to by" a crash or explosion. It states only that the Policies will still apply if the contamination or pollution was "caused by or resulting in" one of the five events. Insurers argue that "the Exclusion plainly provides that there is no coverage under the Policies for any contamination at the Site except that caused by or resulting in a crash, fire, explosion, collision, or in-flight emergency." The Policy does not state that only that portion of a claim which is caused by an enumerated exception will give rise to a duty to defend. It states only that a pollution claim will not give rise to … [a] duty to defend "unless caused by or resulting in a crash fire explosion or collision or a recorded in-flight emergency causing abnormal aircraft operation." There is no apportionment of the percentage of a claim which must be caused by one of the exceptions to give rise to a duty to defend or reimburse.
[Citations omitted.]
Thus, because the underlying claim was vague about the specific causes of contamination and did not foreclose the possibility that some contamination resulted from covered events (plane crashes), the insurers had a duty to defend the town.
Next, the court addressed the "Combined Claims" provision. Under the provision contained in the pollution exclusion, coverage was eliminated for claims that were both covered and uncovered. The insurer contended that this provision was triggered, as the underlying claim involved uncovered and potentially covered pollution claims. The court ruled that a "Combined Claims" requires multiple separate claims, not a single claim with numerous underlying causes. Since NYSDEC brought only one claim against the town, the court ruled that the provision was inapplicable, holding as follows:
However, the Pollution Exclusion does not state that a single claim will be excluded if any portion of the causation for that single claim stems from different forms of pollution. The plain language in the Policies requires more than one claim: not more than one cause underlying a claim. If Insurers wished to make their policy language exclude a duty to defend any single claim which contains allegations of an uncovered cause of harm, they could have expressly done so in the Policies. Therefore, the Court concludes that the "Combined Claims" language is unambiguous in favor of the Town's interpretation.
Hence, the court ruled that there was a duty to defend.
Commentary
The ruling that a duty to defend existed in this case turned on a nonstandard "noise and pollution" exclusion and its carve-out for pollution caused by plane crashes or explosions. Compare that to an earlier Georgia ruling that similarly involved a PFAS contamination claim but resulted in a ruling of no coverage: Grange Ins. Co. v. Cycle-Tex, Inc., No. 4:21-cv-147 (N.D. Ga Dec. 5, 2022). The difference? The Georgia case involved the Insurance Services Office, Inc., Total Pollution Exclusion Endorsement (CG 21 49 09 99), which did not have similar exceptions that restored coverage.
In Insurance Law Reporter, we provide you with this nonstandard "noise and pollution" exclusion so that you can compare the actual wording of the forms from these cases. That is what sets Insurance Law Reporter apart: We don't just summarize the holding; we give you the actual policy language that courts relied on, when available, so you can fully understand why a case was decided.
Opinions expressed in Expert Commentary articles are those of the author and are not necessarily held by the author's employer or IRMI. Expert Commentary articles and other IRMI Online content do not purport to provide legal, accounting, or other professional advice or opinion. If such advice is needed, consult with your attorney, accountant, or other qualified adviser.
One of the emerging exposures for companies is the rise of per- and polyfluoroalkyl substances (PFAS) claims. Courts are being asked to decide whether general liability policies cover these massive nationwide claims. Their answers hinge, as they almost always do, on the precise policy language at issue.
To date, only a handful of court cases have addressed coverage for PFAS claims. Recently, a case from New York was decided that analyzed coverage for an airport where PFAS contamination was alleged. Read below for a full summary of this crucial case for liability insurers.
Subscribers to IRMI's Insurance Law Essentials will receive the following as part of their package.
If you are not a subscriber, click here to subscribe today!
*Except for November and December, when the newsletter is sent monthly.
An Airport Accused of PFAS Contamination Seeks Liability Coverage Despite a Pollution Exclusion
A town in New York operated the Adirondack Regional Airport (the "Airport"). In 2021, the New York State Department of Environmental Conservation (NYSDEC) sent the town a letter identifying it as a potentially responsible party for PFAS contamination at the airport. The contamination originated from the historic use of aqueous film-forming foam (AFFF) in firefighting training exercises, a common practice at airports nationwide.
The NYSDEC requested that the town conduct a site investigation and remediation under New York's environmental conservation laws. The "[l]etter did not refer to any alleged PFAS contamination at the site caused by or resulting in a crash fire explosion or collision or a recorded in-flight emergency causing abnormal aircraft operation."
Eventually, the NYSDEC issued a Superfund Site Classification Notice (the "Notice"), which stated as follows:
The town notified its liability insurer, ACE, which issued an airport owners and operators general liability policy with a pollution liability endorsement. Initially, it agreed to defend under a full reservation of rights based on the policy's pollution exclusion and "Combined Claims" clause. Those provisions stated as follows:
"Combined Claims" was defined as "a claim or claims covered by the policy when combined with any claims excluded by Paragraph 1 [of the Pollution exclusion]."
Another insurer, Westchester, issued a virtually identical policy during a different policy period. Significantly, it contained the same pollution exclusion.
Eventually, the town entered into a "final Order on Consent and Administrative Settlement with NYSDEC relative to the Site." The order stated that "Contamination at the Site appears to be the result of [AFFF] spilled or used for training, responding to plane crashes, and/or for other purposes at the Site."
ACE and Westchester (the "insurers") subsequently advised the town that it would no longer defend them based on the policy's pollution exclusion. ACE stated that, "[b]ecause the NYSDEC Claim involves pollution or contamination, the Insurers have no duty to defend the claim, but only a potential duty to reimburse the Town for defense fees and expenses and damages, if any, properly allocable to pollution or contamination caused by a plane crash, fire, explosion, collision, or in-flight emergency." Prior to this letter, they "paid approximately $1.5 million in defense costs on behalf of the Town for the NYSDEC claim."
A coverage lawsuit was filed in a New York federal district court.
The New York Court Rules a Duty to Defend Exists
In Town of Harrietstown v. Westchester Fire Ins. Co., No. 8:24-CV-1184 (N.D.N.Y. Aug. 18, 2025), the New York federal district court held that the liability insurers owed a duty to defend the underlying suit alleging PFAS contamination. In reaching this result, the court analyzed whether the pollution exclusion barred coverage. The pollution exclusion stated that the policies did "not cover claims directly or indirectly occasioned by, happening through or in consequence of … pollution and contamination of any kind whatsoever." However, the exclusion contained a carve-out that restored coverage for five types of airport events that came within the exception: a crash, fire, explosion, collision, or in-flight emergency causing abnormal aircraft operation.
The insurers argued that this exclusion barred coverage, despite the existence of the carve-outs. The court rejected this argument and held as follows:
Thus, because the underlying claim was vague about the specific causes of contamination and did not foreclose the possibility that some contamination resulted from covered events (plane crashes), the insurers had a duty to defend the town.
Next, the court addressed the "Combined Claims" provision. Under the provision contained in the pollution exclusion, coverage was eliminated for claims that were both covered and uncovered. The insurer contended that this provision was triggered, as the underlying claim involved uncovered and potentially covered pollution claims. The court ruled that a "Combined Claims" requires multiple separate claims, not a single claim with numerous underlying causes. Since NYSDEC brought only one claim against the town, the court ruled that the provision was inapplicable, holding as follows:
Hence, the court ruled that there was a duty to defend.
Commentary
The ruling that a duty to defend existed in this case turned on a nonstandard "noise and pollution" exclusion and its carve-out for pollution caused by plane crashes or explosions. Compare that to an earlier Georgia ruling that similarly involved a PFAS contamination claim but resulted in a ruling of no coverage: Grange Ins. Co. v. Cycle-Tex, Inc., No. 4:21-cv-147 (N.D. Ga Dec. 5, 2022). The difference? The Georgia case involved the Insurance Services Office, Inc., Total Pollution Exclusion Endorsement (CG 21 49 09 99), which did not have similar exceptions that restored coverage.
In Insurance Law Reporter, we provide you with this nonstandard "noise and pollution" exclusion so that you can compare the actual wording of the forms from these cases. That is what sets Insurance Law Reporter apart: We don't just summarize the holding; we give you the actual policy language that courts relied on, when available, so you can fully understand why a case was decided.
Opinions expressed in Expert Commentary articles are those of the author and are not necessarily held by the author's employer or IRMI. Expert Commentary articles and other IRMI Online content do not purport to provide legal, accounting, or other professional advice or opinion. If such advice is needed, consult with your attorney, accountant, or other qualified adviser.