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Citation Insurance Company v. Broan-NuTone LLC

2026-08-28

Summary

Holding. The First Circuit affirmed the district court's grant of summary judgment to the defendants on all breach of implied warranty claims. Citation Insurance did not present the malfunction theory argument in a manner that preserved it for appeal, and even assuming the theory applies, the record contained insufficient circumstantial evidence to permit a fact finder to distinguish between a manufacturing defect and a design defect.

Citation Insurance sued bathroom exhaust fan manufacturer Broan and motor manufacturer Jakel after a fire at an insured home, alleging defects in the fan and motor caused the loss. Citation relied on expert testimony stating the fire originated in the bathroom exhaust fan area and was caused by motor failures, particularly a defective thermal cutoff device, but the expert could not pinpoint which specific deficiency caused the fire. When the District Court excluded portions of the expert's deposition testimony for violating disclosure requirements and granted summary judgment to the defendants, Citation appealed, urging the court to apply the "malfunction theory," which would allow proving a defect existed through circumstantial evidence alone without identifying the specific manufacturing or design flaw.

The First Circuit rejected this argument on procedural and substantive grounds. Although the court did not definitively resolve whether Massachusetts law recognizes the malfunction theory, it found that Citation had forfeited the argument by not presenting it to the district court in a form that would have allowed the defendants a fair opportunity to respond. More fundamentally, even if the malfunction theory applied, Citation provided no circumstantial evidence permitting a reasonable fact finder to distinguish between a manufacturing defect—where the product deviated from its intended design—and a design defect affecting all units of that model.

Summary generated by law.co from the public-domain opinion. The opinion text itself is public domain.

Key issues

  • Whether the malfunction theory applies to allow proof of a product defect without identifying the specific defect
  • Whether a party forfeits arguments by failing to present them to the district court before raising them on appeal
  • Whether expert evidence is required to distinguish manufacturing defects from design defects under Massachusetts law

Procedural posture

Citation Insurance appealed the district court's grant of summary judgment in favor of the defendants on breach of implied warranty and negligence claims brought as subrogee of a homeowner whose residence was damaged in a fire allegedly caused by a defective bathroom exhaust fan.

Authorities cited

Opinion

majority opinion

United States Court of Appeals

For the First Circuit

No. 25-1426

CITATION INSURANCE COMPANY, as subrogee of Peter T. Damore,

Plaintiff, Appellant,

v.

BROAN-NUTONE LLC; JAKEL MOTORS INCORPORATED,

Defendants, Appellees.

APPEAL FROM THE UNITED STATES DISTRICT COURT

FOR THE DISTRICT OF MASSACHUSETTS

[Hon. Margaret R. Guzman, U.S. District Judge]

Before

Barron, Chief Judge,

Lipez and Rikelman, Circuit Judges.

Mark E. Utke, with whom Cozen O'Connor, Patrick J.

Loftus, III, Katherine C. Loftus, and Loftus and Loftus, P.C. were on brief, for appellant.

Christopher A. Duggan, with whom Andrew D. Black and Smith

Duggan Cornell & Gollub LLP were on brief, for appellees.

August 28, 2026

BARRON, Chief Judge. This appeal arises from a lawsuit

that Citation Insurance Company ("Citation") has brought against

Broan-NuTone LLC ("Broan") and Jakel Motors Incorporated ("Jakel")

(together, the "defendants"). Citation is suing as the subrogee

of its insured, a Massachusetts homeowner whose home was damaged

in a fire. The suit alleges that the defendants, the manufacturers

of a bathroom exhaust fan and fan motor in that home, are liable

for that fire under Massachusetts law. The District Court granted

summary judgment to the defendants. We affirm.

I.1

A.

On September 15, 2020, a fire broke out at Peter

Damore's home in Burlington, Massachusetts. Damore was at his

home that day, as was a Verizon technician who was working in the

basement to upgrade the home's Wi-Fi system. Sometime after the

Verizon technician arrived that morning and began working, he

informed Damore that a fuse on the circuit breaker panel in the

basement tripped when he tried to use it. Shortly thereafter,

smoke detectors began to go off on one of the upper floors of the

home, and Damore hurried upstairs to investigate. Upon opening

1 "We draw the facts from the summary judgment record that

was before the [D]istrict [C]ourt, and we array [those facts] in the light most favorable to the nonmoving party." O'Horo v. Bos. Med. Ctr. Corp., 131 F.4th 1, 8 (1st Cir. 2025) (citation

modified).

- 2 -the stairway to the attic, Damore discovered heavy smoke and heard

the crackling of a fire. He and the Verizon technician vacated

the home, and Damore called 911.

The Burlington Fire Department responded and determined

that the main fire was located in the ceiling of the master

bathroom, above the bathroom ceiling fan. A lieutenant observed

"a heavy glow of fire around the metal ceiling fan and darkened

drywall on [the] ceiling next to that glow." After extinguishing

the fire, the Fire Department prepared an incident report, which

documented findings of "obvious charring in [the] area of [the]

ceiling fan, roof joists and rafters immediately above the

[bathroom ceiling] fan," as well as "a lot of charring of [the]

plywood floor above [the] fan." The report recounted the

determination of a trooper that the "fire started with [the]

bathroom vent fan," was "accidental," and had "no connection to

Verizon working on [the] scene."

Damore thereafter submitted an insurance claim pursuant

to his policy with Citation. In response, Citation made

approximately $726,000 in payments to Damore in connection with

damage sustained as a result of the fire.

B.

Citation, as Damore's subrogee, filed suit against the

defendants in federal district court in the District of

Massachusetts based on diversity jurisdiction. Its complaint

- 3 -alleged that the fire in the Damore residence "originated at or

around a defective bathroom exhaust fan manufactured and placed

into the stream of commerce by Broan." It further alleged that

the fire was "caused by the catastrophic failure of [the fan's]

electric motor," which was "designed, manufactured[,] and sold by

Jakel."

As relevant here, the Jakel motor in the Broan fan

contained a thermal cutoff device ("TCO") manufactured by Tamura.2

As the District Court explained, a TCO "is a thermal fuse that is

supposed to melt open when [a] [m]otor reaches a certain

unacceptable temperature," thereby causing power to the motor to

be cut off so that it does not become too hot and ignite a fire.

Citation Ins. Co. v. Broan-NuTone LLC, 793 F. Supp. 3d 299, 303-04

(D. Mass. 2025).

As relevant to this appeal, Citation's complaint set

forth claims against both defendants for negligence and breach of

implied warranty of merchantability.3 As relief, Citation sought

"damages sustained as a direct and proximate cause of the" fire,

as well as "interests and costs."

2 Tamura is not a party in this case.

3 Citation also asserted a claim for breach of implied

warranty in tort. The parties and the District Court treated Citation's implied warranty claims as the same. Neither party argues on appeal that the two claims should be considered

differently, so we follow suit.

- 4 -1.

Citation designated two experts in support of its

claims: Stephen M. Harris, a fire analyst; and Michael Wald, an

electrical engineer.

Harris submitted an expert report stating that the fire

originated at "the mounting position for the master bathroom air

exhaust fan." The report included Harris's opinion "that the fire

originated within the exhaust fan[,] as there [were] no other

competent ignition source(s)" at the location of the fire's origin.

The report did not identify "the specific failure mode within the

exhaust fan."

Wald also submitted an expert report. Because that

report is central to the present dispute, we describe it in some

detail.

In his report, Wald began by detailing his observations

from an examination of the fan (completed jointly with Broan's

representatives), which included the following:

▪ "The fire damage patterns . . .

demonstrate[d] a fire originating at the

fan and then spreading up and out into

the attic."

▪ "Examination of the fan motor coil

revealed two distinct areas of localized

damage to the coil windings." (Citation

omitted.)

▪ "Examination of the [TCO] revealed that

the internal element had melted open and

one of the leads had separated from the

- 5 -body of the device. This supports the

conclusion that this device was exposed

to temperatures well beyond its rating at

some point during the event."

Wald then opined, in relevant part, as follows:

▪ "The damage on the fan motor coil is

quite clearly the result of abnormal

electrical activity (arcing)."

▪ "The presence of electrical activity on

the motor coil, but nowhere else in the

fan supply wiring, not only confirms that

the fan was energized at the time of the

fire but also precludes any damage inside

the fan from having been caused by

external fire attack. . . . Thus, the

possibility of a fire originating at any

other wiring [in the attic] can be

eliminated."

▪ "[T]he short amount of time between when

the breaker was being operated [by the

Verizon technician] and the detection of

the fire precludes the resetting of the

breaker from having been associated with

causing the fire."

▪ "The root cause of these failures is

deficiencies in the design and

manufacture of [Broan fans equipped with

Jakel motors and Tamura TCOs] such that

the motor coil can be subjected to

temperatures which damage the insulation

on the coil windings. Once this occurs

there is an unintended flow of

electricity from one winding to adjacent

windings . . . . and eventually arcing

failures develop."

▪ "There is no evidence that this fan was

improperly installed, improperly

maintained, or modified since it was

purchased. It was being used in its

originally intended manner. Thus, it is

concluded that this fan was in a

- 6 -deficient condition when it left the

hands of the manufacturer."

Finally, Wald's expert report additionally stated:

▪ "The propensity of Broan fans equipped

with Jakel motors and Tamura [TCOs] to

start fires is well known and discussed

in several papers on the subject . . . .

This investigator has examined dozens of

fans that have caused fires which have

th[e] same damage pattern [as the fan

here]."

▪ "While the installation of a [TCO] can

often detect an overheating event before

it develops into winding failures, the

Tamura [TCO] is known to be particularly

unreliable. Testing performed by others

has demonstrated the inability of this

device to remove power from overheating

windings. Moreover, as noted above, this

investigator has seen numerous

real-world examples of Tamura [TCOs]

failing to prevent coil winding

failures."

The defendants deposed Wald. At that deposition, Wald

described three specific deficiencies that have been documented to

occur in TCOs, including: (1) degradation of the TCO as a result

of exposure to the fan's normal operating temperature; (2) a

failure that allows TCOs to continue conducting electricity even

after they have melted open; and (3) improper bending of the TCO

lead wire during installation. As to the fan in question, Wald

testified that the TCO lead wire had "been bent in violation of

the [TCO] instructions," but that he "could not tell after the

fire" whether the bend had caused specific further damage likely

- 7 -to lead the TCO to fail. He further stated, "I don't know why the

TCO failed. I just know it did."

Wald also testified that numerous alternative designs

would, in his view, improve fan reliability and/or reduce the risk

of fire, including: encasing the fan motor in metal, using

noncombustible or fire-resistant plastics, or installing a

mechanical TCO or multiple TCOs. As to those alternatives,

however, he stated that he did not know how much they would cost

or what specific modifications to the subject fan's design would

be necessary to accommodate them.

2.

The defendants filed a motion for summary judgment. The

motion argued that Citation had not introduced sufficient expert

evidence to prevail on its implied warranty claims under either

(1) a manufacturing defect theory or (2) a design defect theory.

As to Citation's implied warranty claims insofar as they

were based on a manufacturing defect theory, the defendants pointed

to Wald's deposition testimony stating that he could not opine as

to the specific TCO defect that caused the fire. They argued that

the absence of expert evidence on that score was fatal to a

manufacturing-defect-based implied warranty claim. See Fernandes

v. Union Bookbinding Co., 507 N.E.2d 728, 735 (Mass. 1987) ("In

order to invoke the implied warranty of merchantability under

[Mass. Gen. Laws Ann. ch. 106,] § 2-314, a plaintiff must

- 8 -demonstrate that the damages complained of were proximately caused

by a defect or breach which existed at the time of the sale.").

As to Citation's implied warranty claims insofar as they

were based on a design defect theory, the defendants argued that

Citation also could not prevail. Here, they pointed to the fact

that Wald had testified that he was not aware of the costs or

ramifications of adopting the alternative designs he had

identified. See Evans v. Lorillard Tobacco Co., 990 N.E.2d 997,

1024 (Mass. 2013) ("In claims alleging . . . a design defect in

breach of the implied warranty of merchantability, the plaintiff

must show an available design modification which would reduce the

risk without undue cost or interference with the performance of

the product . . . ." (citation modified)).4

Citation opposed the defendants' summary judgment

motion. First, as to its evidentiary burden under a

manufacturing-defect-based theory of its claims, Citation argued

that Massachusetts courts do not require plaintiffs to identify

"the exact" cause of an accident so long as "they can rule out

other potential causes." (Quoting Collins v. Sears, Roebuck &

4 The defendants argued that the negligence claims similarly

failed because Citation failed to show (1) that a defect caused the fire or (2) that the defendants were negligent in failing to adopt an alternative design. On appeal, Citation does not dispute that it cannot prevail on its negligence claims unless it makes one of those showings, and so we proceed to treat its negligence and breach of implied warranty claims together.

- 9 -Co., 583 N.E.2d 873, 874 (Mass. App. Ct. 1992).) Citation

contended that, "[i]n Massachusetts, negating all other sources of

injury is not treated as a distinct legal theory but is instead

considered another factor in determining whether the plaintiff can

show a greater probability than not that the relevant accident or

injury resulted from the defendant's negligence." (Citing Walker

v. Gen. Elec. Co., 968 F.2d 116, 119-20 (1st Cir. 1992) (citation

modified).)

Citation argued that summary judgment was not warranted

under that standard on a manufacturing defect theory of its claims

because it had shown "'a greater probability than not' that the

fire was caused by the [f]an's faulty TCO." It first pointed to

the fact that Harris, the Burlington Fire Chief, and Wald had all

concluded that "the fire originated in the area of the bathroom

exhaust fan." It then noted, citing Wald's deposition, that Wald

had "consistently reiterated his expert finding that the fire was

caused by a manufacturing defect in the TCO." Citation

acknowledged that Wald "also identified three well-documented

deficiencies with the TCO at issue," but it argued that it was

"unnecessary" for him to specify which of those deficiencies caused

the fire, as "such specificity is not necessary" under

Massachusetts law "where, as here, the fire destroyed important

pieces of evidence . . . that would help to prove how the coil in

the TCO failed."

- 10 -Citation then argued as to a design-defect-based theory

of its claims that all it needed to do to survive summary judgment

was "offer evidence that th[e alternative] design is currently

being used in similar products in the market or, at least, that

such a design could have reasonably been produced." (Citing Evans,

990 N.E.2d at 1015.) It contended that it had satisfied that

standard because Wald identified several design alternatives in

his deposition testimony that "are already being used or are

available in the market."

The District Court granted summary judgment to the

defendants on all claims. Citation Ins. Co., 793 F. Supp. 3d at

303. In doing so, the District Court began by analyzing the

"[t]hreshold [q]uestion" of whether Citation had violated Federal

Rule of Civil Procedure 26(a)(2)(B). Id. at 309. That Rule

requires parties, in disclosing expert witnesses, to provide "a

written report" containing, among other things, "a complete

statement of all opinions the witness will express and the basis

and reasons for them." Fed. R. Civ. P. 26(a)(2)(B)(i). The

District Court determined that Citation had violated that Rule

with respect to Wald because Wald had opined on three matters that

had not been clearly identified in his expert report: (1) an

alleged specific manufacturing defect; (2) how any such defect

caused the fire at issue; and (3) potential design alternatives

and their feasibility. Citation Ins. Co., 793 F. Supp. 3d at

- 11 -309-10. The District Court concluded that the "most appropriate"

sanction for those violations was exclusion of those portions of

Wald's deposition testimony. Id. at 311.

The District Court reasoned that those exclusions

provided a sufficient basis for granting summary judgment to the

defendants. Id. That was so, the District Court explained,

because "the first two" pieces of excluded testimony "relate to

essential elements of [Citation]'s manufacturing defect

claim" -- namely, the identification of a specific defect that

caused the fire. Id.; see also id. at 309-10. The District Court

further explained that the third piece of excluded evidence

"relates to an essential element of [Citation]'s design defect

claim" -- namely, available design modifications and their

potential costs and ramifications. Id. at 311; see also id. at

310.

The District Court went on to consider, "in the interest

of completeness," the merits of Citation's claims had it not

excluded the testimony in question. Id. at 311. It began by

explaining that, "given the complexity of the product at issue,"

expert testimony was necessary to prevail on either a manufacturing

or design defect theory. Id. at 313. It then found that the

defendants were entitled to summary judgment under a manufacturing

defect theory for "two independently sufficient reasons": (1) the

record did not establish that the particular fan at issue "deviated

- 12 -from its intended design" and (2) expert testimony was necessary

on the issue of causation, yet Wald had "conceded at [his]

deposition that he did not know whether the alleged manufacturing

defect that he identified caused the fire." Id. at 313-14. The

District Court then concluded that the defendants were also

entitled to summary judgment on a design defect theory because of

the absence of expert testimony as to whether an alternative design

"would be unduly costly and/or would affect performance of the

machinery." Id. at 314.

Citation timely appealed.

II.

We review the District Court's grant of summary judgment

to the defendants de novo. See Miceli v. JetBlue Airways Corp.,

914 F.3d 73, 80 (1st Cir. 2019). "Summary judgment is appropriate

where the record, viewed in the light most favorable to the

nonmoving party" -- here, Citation -- "discloses no genuine

dispute as to any material fact and demonstrates that the

movant[s]" -- here, the defendants -- are "entitled to judgment as

a matter of law." McCoy v. Town of Pittsfield, 59 F.4th 497, 504

(1st Cir. 2023) (citation modified); accord Fed. R. Civ. P. 56(a).

In conducting our review, "[w]e are not bound by the [D]istrict

[C]ourt's reasoning" but "may affirm the entry of summary judgment

on any ground apparent from the record." McGunigle v. City of

Quincy, 835 F.3d 192, 202 (1st Cir. 2016) (citation modified).

- 13 -"A federal court sitting in diversity applies state

substantive law." Levin v. Dalva Bros., 459 F.3d 68, 73 (1st Cir.

2006). Under Massachusetts law, a warranty of merchantability is

implied in contracts for the sale of goods when sold by merchants

of such goods. See Mass. Gen. Laws Ann. ch. 106, § 2-314 (West

2026).

To prevail on a breach of warranty of merchantability

claim under Massachusetts law, a plaintiff must establish the

following elements:

(1) that the defendant manufactured or sold

the product; (2) that a defect or unreasonably

dangerous condition existed at the time the

product left the defendant's hands so that it

was not reasonably suitable for the ordinary

uses for which goods of that kind were sold;

(3) that at the time of his injury, the

plaintiff was using the product in a manner

that the defendant intended or that could

reasonably have been foreseen; and (4) that

the defect or unreasonably defective condition

was a legal cause of the plaintiff's injury.

Lally v. Volkswagen Aktiengesellschaft, 698 N.E.2d 28, 43 (Mass.

App. Ct. 1998) (citation modified).

As relevant here, a product may be considered defective

under the second element "because of [(1)] a manufacturing defect,

[(2)] a design defect, or [(3)] a warning defect." Evans, 990

N.E.2d at 1010. A manufacturing defect occurs when a product

deviates from its intended design due to an error in manufacturing.

See Back v. Wickes Corp., 378 N.E.2d 964, 970 (Mass. 1978) (stating

- 14 -that, in "a case involving a manufacturing defect, the jury might

simply compare the propensities of the product as sold with those

which the product's designer intended it to have"). A design

defect, in contrast, occurs when a product is manufactured as

intended, but the product's design poses "foreseeable risks of

harm" that "could have been reduced or avoided by the adoption of

a reasonable alternative design." Evans, 990 N.E.2d at 1011

(internal quotation marks omitted) (quoting Restatement (Third) of

Torts: Products Liability § 2(b) (A.L.I. 1998)).

III.

On appeal, Citation argues that the District Court erred

in granting summary judgment to the defendants on the breach of

implied warranty claims by premising its ruling on Citation's

failure to provide admissible expert evidence as to a specific

manufacturing or design defect that could support such a claim.

In so contending, Citation faults the District Court for failing

to apply the "malfunction theory." In support of this challenge,

Citation contends that Massachusetts courts have recognized the

malfunction theory and that the theory permits a plaintiff to show

circumstantial evidence of a defect without showing that defect to

have been caused by the product's design or how it was

manufactured.

The defendants dispute whether Massachusetts law

recognizes the malfunction theory at all. They further dispute

- 15 -whether Massachusetts law does so even when, as here, no expert

opined that destruction of the assertedly malfunctioning product

made it impossible to identify the defect in that product that

caused the malfunction. We need not resolve either dispute,

however, to reject Citation's challenge on appeal. As we will

explain, even if we were to resolve each of these disputes in

Citation's favor, we still would reject its challenge to the grant

of summary judgment.

A.

We can easily dispense with the portion of Citation's

malfunction-theory-based challenge to the grant of summary

judgment that takes aim at the District Court for faulting Citation

for failing to provide admissible expert evidence sufficient to

show a design defect. See Citation Ins. Co., 793 F. Supp. 3d at

314. The reason that we may do so has to do with the arguments

that Citation made to the District Court in opposing the

defendants' motion for summary judgment.

In doing so, Citation did not rely on the malfunction

theory that it now invokes on appeal. It instead argued that it

had introduced sufficient evidence of alternative designs to

create a genuine dispute of material fact as to a design defect

theory of its claims. And, in support of that contention, Citation

relied solely on Wald's deposition testimony.

- 16 -Citation does not challenge on appeal, however, the

District Court's exclusion of Wald's deposition testimony. It

instead contends that it introduced "sufficient circumstantial

evidence and evidence excluding secondary causes of the fire" to

survive summary judgment under the malfunction theory. Nor does

Citation develop an argument that other evidence in the record

suffices to show a genuine dispute of material fact as to

reasonable alternative designs.

Citation did not argue below that, under the malfunction

theory, it did not need to introduce evidence of alternative

designs to prevail on a design defect theory of its claims. As a

result, it cannot now challenge the District Court's ruling on

that ground. See Morales Feliciano v. Rullan, 378 F.3d 42, 49

(1st Cir. 2004) ("It is a bedrock rule that when a party has not

presented an argument to the district court, he may not unveil it

in the court of appeals." (citation modified)). We therefore see

no basis for concluding that the District Court erred in granting

the defendants' summary judgment motion as to Citation's

design-defect-based theory of its implied warranty claims.

B.

There remains to address Citation's challenge to the

District Court's grant of summary judgment to the defendants as to

the manufacturing-defect-based theory of those same claims. Here,

the District Court faulted Citation for failing to provide

- 17 -admissible expert evidence supportably showing a manufacturing

defect. See Citation Ins. Co., 793 F. Supp. 3d at 313-14.

Citation contends that the District Court erred in so ruling.

Citation argues that the malfunction theory applies to those claims

and that, under that theory, it did not need to provide such expert

evidence.

Citation is in a stronger position in advancing this

challenge than it was in advancing its design-defect-related

challenge. After all, it did advance the malfunction theory below

as to its manufacturing-defect-based theory. Nonetheless, we

still conclude that the challenge is without merit, given the

District Court's reasons for granting summary judgment and the way

that Citation deployed the malfunction theory in the proceedings

below.

Specifically, in granting summary judgment with respect

to Citation's manufacturing-defect-based argument, the District

Court reasoned in part as follows. It explained that Citation

failed to introduce evidence showing how the fan or its motor

"deviated from their intended design." Id. at 313. It then

determined that, accordingly, "no factfinder would be able to

perform their duty to 'compare the propensities of the product as

sold with those which the product's designer intended it to have.'"

Id. (quoting Back, 378 N.E.2d at 970).

- 18 -We fail to see how the malfunction theory undermines

that reasoning. In the proceedings before the District Court,

Citation chose to rely on the malfunction theory solely to show

that there was a manufacturing defect. That choice necessarily

invited the District Court to conclude that Citation had to show

how, via circumstantial evidence, an inference could be drawn that

a manufacturing defect caused the fire. Citation does not point

to anything in the record, however, that supports that more

particularized inference, even accounting for the malfunction

theory.

After all, on Citation's own account of the malfunction

theory, it does not, in and of itself, necessarily distinguish

between manufacturing and design defects. So, even if the District

Court had applied the malfunction theory to infer the existence of

a defect, we fail to see how the application of that theory could

have led the District Court to conclude that a factfinder could

"compare the propensities of the product as sold with those which

the product's designer intended it to have." Back, 378 N.E.2d at

970.

To be sure, we might conclude differently if Citation

could show that the record reveals circumstantial evidence from

which a fact finder could infer not only that a defect caused the

fire but also that it was a manufacturing rather than a design

defect. But Citation has not done so.

- 19 -In its filing in opposition to summary judgment with

respect to a manufacturing-defect-based theory of its claims,

Citation identified three potential "deficiencies with the TCO at

issue that could have ignited the fire":

(1) that the TCO was only rated for 90 degrees

centigrade for an extended period of time and

could degrade when exposed to higher

temperatures, (2) that its eutectic fusible

element can melt but remain in a pool such

that it continues to conduct electricity, and

(3) that bending the TCO in violation of the

instructions that come with it can cause a

fire.

It is far from clear, however, that a layperson would be equipped

to conclude, absent expert evidence, that all those deficiencies

would be due to a defect in manufacturing rather than design. For

example, it is not apparent that the temperature rating of the TCO

at issue here deviated from "identical products issued from the

same manufacturer," Wasylow v. Glock, Inc., 975 F. Supp. 370, 377

(D. Mass. 1996), such that such a defect would be attributable to

a manufacturing error.

We recognize that Citation argues on appeal that, under

the malfunction theory, it need not identify a specific

manufacturing or design defect so long as the circumstantial

evidence supports an inference that the product at issue was

generally defective. But, as we have already explained, Citation

did not present that argument below. Instead, it chose to rely on

expert evidence of reasonable alternative designs -- and not the

- 20 -malfunction theory -- to advance a design-defect-based theory of

its implied warranty claims. That choice invited the District

Court to reject Citation's attempt to show there was a genuine

issue of triable fact as to the existence of a design defect, for

the very reason that Citation had failed to provide sufficient

expert evidence to show that any defect was a design defect. See

Citation Ins. Co., 793 F. Supp. 3d at 314.

In turn, Citation's choice to rely on the malfunction

theory solely for its manufacturing-defect-based theory invited

the District Court to conclude that Citation must show sufficient

circumstantial evidence to allow a jury to infer the existence of

a manufacturing defect. But, as we have explained, Citation has

not explained how the District Court erred in concluding that no

such showing had been made.

We acknowledge that it might appear odd to reject the

application of the malfunction theory to Citation's

manufacturing-defect-based claim on the ground that Citation

failed to provide sufficient evidence specifically showing a

manufacturing defect, given that such specificity is arguably not

required under the malfunction theory. Nonetheless, having

conducted the litigation as it did in the District Court and having

chosen not to rely on the malfunction theory in support of a

design-defect-based claim, Citation is stuck with the consequences

of that approach. See Orenstein v. United States, 191 F.2d 184,

- 21 -193 (1st Cir. 1951) ("An appellant will not ordinarily be permitted

to complain of an error which he himself invited . . . ."); see

also Box Pond Ass'n v. Energy Facilities Siting Bd., 758 N.E.2d

604, 615 n.14 (Mass. 2001) (same). We therefore cannot agree that

the District Court erred in granting summary judgment to the

defendants on Citation's implied warranty claims.

IV.

For the foregoing reasons, we affirm.

- 22 -