NOT FOR PUBLICATION

UNITED STATES COURT OF APPEALS

 FOR THE NINTH CIRCUIT

WESCO INSURANCE COMPANY, a

Delaware corporation,

Plaintiff-Appellee,

 v.

BRAD INGRAM CONSTRUCTION,

Defendant-Appellant.

No. 22-16584

D.C. No. 3:21-cv-05682-WHO

MEMORANDUM*

Appeal from the United States District Court

for the Northern District of California

William Horsley Orrick, District Judge, Presiding

Argued and Submitted November 13, 2023

San Francisco, California

Before: S.R. THOMAS, FORREST, and MENDOZA, Circuit Judges.

Dissent by Judge FORREST.

Brad Ingram Construction (“Ingram”) appeals the district court’s judgment 

that Ingram’s insurer, Wesco Insurance Company (“Wesco”), does not have a duty

to defend Ingram in connection with injuries caused by airborne wildfire debris. 

FILED

JAN 23 2024

MOLLY C. DWYER, CLERK

U.S. COURT OF APPEALS

* This disposition is not appropriate for publication and is not precedent

except as provided by Ninth Circuit Rule 36-3.
The sole question on appeal is whether, under California law, there was any

potential for coverage given the pollution exclusion provision in Ingram’s

insurance policy.

1

 Because we conclude that there was a potential for coverage, we

reverse. 

We have jurisdiction pursuant to 28 U.S.C. § 1291. We review the district

court’s grant of summary judgment de novo. Flores v. City of San Gabriel, 824

F.3d 890, 897 (9th Cir. 2016). Likewise, “the interpretation of [an] insurance

policy is a question of law for the court and is reviewed de novo” as well. McHugh

v. United Serv. Auto. Ass’n, 164 F.3d 451, 454 (9th Cir. 1999).

Because the parties are familiar with the facts and the procedural history, we

will not recount them here.

I 

Under California law, insurance policies are construed in accordance with

“general rules of contract interpretation” that aim to “give effect to the ‘mutual

intention’ of the parties.” MacKinnon v. Truck Ins. Exch., 73 P.3d 1205, 1212

(Cal. 2003) (quoting Cal. Civ. Code § 1636). “The determination whether [an]

1

 The provision in question excludes coverage for “‘Bodily injury’ or

‘property damage’ which would not have occurred in whole or part but for the

actual, alleged or threatened discharge, dispersal, seepage, migration, release or

escape of ‘pollutants’ at any time.”

2
insurer owes a duty to defend usually is made in the first instance by comparing the

allegations . . . with the terms of the policy.” Horace Mann Ins. Co. v. Barbara B.,

846 P.2d 792, 795 (Cal. 1993). Coverage provisions are “interpreted broadly so as

to afford the greatest possible protection to the insured,” whereas “exclusionary

clauses are interpreted narrowly against the insurer.” MacKinnon, 73 P.3d at 1213

(quoting White v. W. Title Ins. Co., 710 P.2d 309, 313 (Cal. 1985)). “[T]he burden

is on the insurer to prove the claim is specifically excluded.” Aydin Corp. v. First

State Ins. Co., 959 P.2d 1213, 1215 (Cal. 1998). 

Applying these principles in MacKinnon, the California Supreme Court held

that a pollution exclusion applies only to “injuries arising from events commonly

thought of as pollution, i.e. environmental pollution . . . .” MacKinnon, 73 P.3d at

1216. To determine whether a pollution event has occurred, the reviewing court

should consider both the character of the injurious substance and whether exposure

occurred due to a mechanism specified in the policy. Id. at 1213–16. Under

MacKinnon, neither the substance nor the mechanism of exposure is dispositive;

they are to be considered “in conjunction” with one another. Id. at 1215. See

Garamendi v. Golden Eagle Ins. Co., 25 Cal. Rptr. 3d 642, 646–48 (Cal. Ct. App.

2005); Ortega Rock Quarry v. Golden Eagle Ins. Corp., 46 Cal. Rptr. 3d 517,

525–26 (Cal. Ct. App. 2006); Cold Creek Compost, Inc. v. State Farm Fire & Cas.

3
Co., 68 Cal. Rptr. 3d 216, 224–25 (Cal. Ct. App. 2007); The Villa Los Alamos

Homeowners Assn. v. State Farm Gen. Ins. Co., 130 Cal. Rptr. 3d 374, 383–85

(2011); JRK Prop. Holdings, Inc. v. Colony Ins. Co, 313 Cal. Rptr. 3d 895,

905–09 (Cal. Ct. App. 2023).

In addition, under California law, an insurer’s duty to defend and its duty to

indemnify are not synonymous. Certain Underwriters at Lloyd’s of London v.

Superior Ct., 16 P.3d 94, 102–03 (Cal. 2001). The duty to defend is broader than

the duty to indemnify. Id. “An insurer has a duty to defend when the policy is

ambiguous and the insured would reasonably expect the insurer to defend him or

her against the suit based on the nature and kind of risk covered by the policy, or

when the underlying suit potentially seeks damages within the coverage of the

policy.” Foster-Gardner, Inc. v. Nat’l Union Fire Ins. Co., 959 P.2d 265, 273

(Cal. 1998).

“To prevail in an action seeking declaratory relief on the question of the duty

to defend, the insured must prove the existence of a potential for coverage, while

the insurer must establish the absence of any such potential. In other words, the

insured need only show that the underlying claim may fall within policy coverage;

the insurer must prove it cannot. The duty to defend exists if the insurer becomes

aware of, or if the third party lawsuit pleads, facts giving rise to the potential for

4
coverage under the insuring agreement.” Delgado v. Interinsurance Exch. of Auto.

Club of S. Cal., 211 P.3d 1083, 1086 (Cal. 2009) (internal citations and quotations

omitted). 

II

In this case, a truck driver was allegedly injured by “expos[ure] . . . to clouds

of toxic dust during the loading and unloading of his truck.” The allegations do

not specify the composition of the dust except to say that the wildfire waste

consisted of “ash, debris, metal, concrete, and contaminated soil.” As to the

mechanism of exposure, the driver alleges that onsite workers “stirred up” the dust

deposited in the environment by the fire while “load[ing] debris” and again when

the debris was uncovered and “dump[ed]” at the waste facility. We conclude that

while wildfire debris may be considered a “pollutant” in certain circumstances, the

mechanism of exposure described in the complaint does not clearly constitute an

“event commonly thought of as pollution.” MacKinnon, 73 P.3d at 1216 (emphasis

added). 

MacKinnon noted that “terms such as ‘commonly thought of as pollution,’

or ‘environmental pollution,’ are not paragons of precision.” Id. at 1217. There is

no California case directly on point as to dust created or disbursed by a naturally

occurring event. California courts have noted that, in considering a matter of first

5
impression, courts should be cautious of relieving an insurer of its duties under the

policy. Ortega Rock Quarry, 46 Cal. Rptr. 3d at 528 (quoting Pa. Nat'l Mut. Cas.

Ins. Co. v. Triangle Paving, Inc., 973 F. Supp. 560, 566–67 (E.D.N.C. 1996)). 

“Any doubt as to whether the facts establish the existence of the defense

duty must be resolved in the insured’s favor.” Montrose v. Superior Ct., 861 P.2d

1153, 1160 (Cal. 1994); accord Anthem Elecs., Inc. v. Pac. Emps. Ins. Co., 302

F.3d 1049, 1054 (9th Cir. 2002). Given the test in MacKinnon, which has not been

applied in sufficiently analogous cases, and the fact that the pollution exclusion

does not apply unambiguously to the driver’s injuries, there existed a potential for

coverage under the insurance policy, and Wesco had a duty to defend the litigation. 

We do not opine as to whether Wesco would have had a duty to indemnify, if

damages were awarded.

REVERSED.

6
Wesco Insurance Company v. Brad Ingram Construction, No. 22-16584

Forrest, J., dissenting: 

While I agree with the majority’s statement of the governing legal standard, I 

disagree with its application of that standard. As the majority explains, the California 

Supreme Court has held that a pollution exclusion like the one at issue here applies 

only to “injuries arising from events commonly thought of as pollution, i.e. 

environmental pollution.” MacKinnon v. Truck Ins. Exch., 73 P.3d 1205, 1216 (Cal. 

2003), as modified on denial of reh’g (Sept. 17, 2003). In determining whether an 

event would be understood as an act of pollution, courts consider two factors: the 

substance (alleged pollutant) and the mechanism of exposure of the substance; 

neither factor is itself dispositive. Id. at 1216–17; Villa Los Alamos Homeowners 

Ass’n v. State Farm Gen. Ins. Co., 130 Cal. Rptr. 3d 374, 380–81 (Ct. App. 2011).

California caselaw indicates that the circumstances at issue here would be commonly 

understood as an act of pollution, thus triggering the pollution exclusion, as the 

district court held. Therefore, I respectfully dissent.

I.

Turning first to the substance at issue, the underlying complaint alleges that 

the employee’s injury stemmed from exposure to “clouds of toxic dust.” The dust 

directly resulted from a massive wildfire, but the “clouds” of particles that allegedly 

FILED

JAN 23 2024

MOLLY C. DWYER, CLERK

U.S. COURT OF APPEALS
2 

caused injury were created when the dust was disturbed by the wildfire cleanup 

project.1

Even though the dust was originally created by a wildfire and may consist of 

natural material, that does not prevent it from being part of a pollution event. 

California courts have recognized that natural materials can be pollutants. See 

Ortega Rock Quarry v. Golden Eagle Ins. Corp., 46 Cal. Rptr. 3d 517, 525 (Ct. App. 

2006) (“[H]azardous substances are not rendered non-polluting by the fact that they 

are naturally occurring . . . .” (quoting Gold Fields Am. Corp. v. Aetna Cas. & Sur. 

Co., 744 N.Y.S. 2d 395, 396 (2002))). In Ortega Rock Quarry, a quarry operator 

placed fill dirt along a road after highwaters washed out portions of the road. 46 Cal. 

Rptr. 3d at 519–520. Even though the rocks and dirt were natural materials, the 

California Court of Appeal held that they were nonetheless a pollutant given the 

regulation of waterways and that these materials were placed by human activity. Id. 

at 525–26. Likewise, in Cold Creek Compost, Inc. v. State Farm Fire & Casualty

Co., the California Court of Appeal held that “[h]eavy clouds of dust from . . . 18 

wheeler double-wide trucks” triggered the pollution exclusion despite arguments 

1

In the opening brief, Appellant Brad Ingram Construction (Ingram) argues 

that the underlying injury may have been caused by bacteria. The underlying 

complaint, however, makes no mention of bacteria and instead alleges the injury was 

caused by toxic dust and debris. “Determination of the duty to defend depends, in 

the first instance, on a comparison between the allegations of the complaint and the 

terms of the policy.” Scottsdale Ins. Co. v. MV Transp., 115 P.3d 460, 466 (Cal. 

2005). 
3 

that “dust is not commonly thought of as a pollutant.” 68 Cal. Rptr. 3d 216, 220, 229 

(Ct. App. 2007). The court explained that “[d]ust has been held to be a pollutant 

within the meaning of the pollution exclusion in California and elsewhere, and dust 

is recognized and regulated as a form of air pollution under California environmental 

law.” Id. at 229 (citations omitted); see also id. at 226 n.5 (applying a pollution 

exclusion to compost odors from “100% natural, organic materials” and rejecting 

the suggestion that the odors could not qualify as a pollutant given their “natural” 

origin); Garamendi v. Golden Eagle Ins. Co., 25 Cal. Rptr. 3d 642, 648 (Ct. App. 

2005) (applying the pollution exclusion to silica dust, a “natural product”).

These cases establish that simply because the substance at issue is dust does 

not prohibit it from being a pollutant. And the dust alleged here is not simply dirt—

it is toxic dust located in a heavily regulated cleanup area.

The context at issue further informs this analysis. While a wildfire created the 

toxic dust, the government required that prime contractors performing the cleanup

“be certified for hazardous substance removal” because the debris “was known to be 

a health hazard.” Workers at the cleanup sites wore protective clothing and 

respirators. On-site crews were expected to don and doff protective equipment in

designated decontamination zones. Air monitoring stations were set up around the 

community to track airborne toxins. 
4 

The policy defines pollutants as “any solid, liquid, gaseous or thermal irritant 

or contaminant, including smoke, vapor, soot, fumes, acids, alkalis, chemicals and 

waste.” Given the level of precautions here, concluding that the dust is a pollutant is 

a far cry from the hypotheticals considered unreasonable in MacKinnon. See 73 P.3d 

at 1214 (noting the absurdity in applying the pollutant label to pool chlorine—an 

irritant—used for its ordinary purpose if it were to cause an allergic reaction). 

II.

Turning to the mechanism that caused the alleged injury, see Villa Los 

Alamos, 130 Cal. Rptr. 3d at 383, the pollution exclusion applies where a “discharge, 

dispersal, seepage, migration, release or escape” of a pollutant occurs. The parties 

focus on different acts of dispersal or release. Appellee Wesco Insurance Company

(Wesco) contends the cleanup project is the proper focus, while Ingram focuses on 

the wildfire. But the complaint makes clear that the cleanup project is the proper

focus because it alleges the injury stemmed from the cleanup effort “stirr[ing] up” 

toxic dust.

Focusing on the cleanup, Ingram argues that there was no “release”2 because 

the toxic material was not contained—it was “on the ground” and “open to the 

elements.” Ingram relies on MacKinnon, which stated that a release implies “some 

2Because the district court found a release, it did not consider whether a 

dispersal occurred. I do the same.
5 

sort of freedom from containment.” 73 P.3d at 1215. Ingram further argues, through 

dictionary definitions, that a release can only occur when there is a “protective 

barrier” or an escape from “a structure.” This overly restrictive interpretation of 

“release” is not persuasive.3 Rather, the asbestos context is instructive. A California 

court found a “release” when workers scraped acoustical popcorn off ceiling tiles, 

which released asbestos into the air. Villa Los Alamos, 130 Cal. Rptr. 3d at 384–86. 

“When asbestos is disturbed by construction and related activities, the result is 

commonly referred to as a ‘release’ of asbestos . . . .” Id. at 384 (emphasis added); 

see also Cal. Lab. Code § 6501.8(a) (“‘[A]sbestos-related work’ means any activity 

which by disturbing asbestos-containing construction materials may release

asbestos fibers into the air . . . .” (emphasis added)).

Here, the toxic dust was on the ground, and it was then “stirred up” by the 

massive cleanup operation, which released the dust into the air to create “clouds” of 

dust particles. Cf. Cold Creek Compost, 68 Cal. Rptr. 3d at 224–25 (finding odors 

emanating into the air from composting materials to be a release absent discussion 

or reference to a protective barrier). That the underlying complaint alleges only one 

worker was injured is of no moment. Cf. Am. Cas. Co. of Reading, Pa. v. Miller, 71 

3Similarly, the California Supreme Court found it absurd to describe the 

normal spraying of pesticides in a residential area as a “release.” MacKinnon, 73 

P.3d at 1215–16. This was so even though the pesticides were likely sprayed from 

some sort of containment. Accordingly, a “protective barrier” is not solely 

determinative when considering a release.
6 

Cal. Rptr. 3d 571, 581 (Ct. App. 2008) (“The test in MacKinnon is not based upon 

the extent of injury, but upon the type of pollutant and how it is released into the 

environment.”). Nor does it matter here that the injury involved an employee injured 

through his employment. Cf. Garamendi, 25 Cal. Rptr. 3d at 644 (applying the 

exclusion to claims brought by workers injured by silica dust throughout their 

employment).

III.

Considering the substance and the mechanism of exposure together, a 

reasonable insured would view the circumstances alleged to have caused injury to 

be “an act of pollution.” MacKinnon, 73 P.3d at 1217. The activity in Villa Los 

Alamos was “a commercial operation, namely the removal of asbestos-containing 

ceiling material by a licensed general contractor, work that is tightly regulated and 

entails notification, and highly technical protocols for asbestos removal, 

containment and waste disposal.” 130 Cal. Rptr. 3d at 386. Likewise, here the 

wildfire cleanup was a regulated operation in part because of contamination and 

human health concerns. Therefore, I would affirm the district court’s conclusion that 

the pollution exclusion applies, and Wesco does not have a duty to defend Ingram 

against the underlying action. I respectfully dissent.