An insurer's $726,000 subrogation claim collapsed on appeal after its own expert admitted he couldn't say why a bathroom fan caught fire.
On August 28, 2026, the US Court of Appeals for the First Circuit affirmed summary judgment for Broan-NuTone and Jakel Motors, ending Citation Insurance Company's effort to recover the roughly $726,000 it paid on a fire claim.
Citation sued as subrogee of a Massachusetts homeowner - stepping into his shoes to pursue whoever it blamed for the loss. The fire started at the home in Burlington on September 15, 2020. The Burlington Fire Department traced it to the ceiling above the master bathroom fan, and a trooper ruled the blaze "accidental" and found it "started with [the] bathroom vent fan." Citation paid the claim, then turned on the fan's makers.
Its theory was a defective bathroom exhaust fan built by Broan, running on a motor made by Jakel. Inside the motor sat a thermal cutoff device, or TCO - a fuse meant to melt open and cut power before the motor overheats. The TCO was made by Tamura, which was not a party to the case.
Citation brought claims for negligence and breach of implied warranty of merchantability - the promise that goods are fit for ordinary use. To win, it had to identify a defect. That is where its case fell apart.
Citation's electrical engineer flagged three possible TCO "deficiencies," but conceded at his deposition, "I don't know why the TCO failed. I just know it did." The district court found his report had not disclosed key opinions as required and excluded those parts of his testimony. Without them, it granted summary judgment.
On appeal, Citation leaned on the "malfunction theory," which lets a plaintiff show a defect through circumstantial evidence without naming the exact flaw. The First Circuit didn't decide whether Massachusetts even recognizes the theory, because it didn't need to.
On the design defect claim, Citation had relied only on its expert's excluded testimony and never raised the malfunction theory below - so it couldn't raise it for the first time on appeal. On the manufacturing defect claim, it had used the theory only to argue that a defect existed, not that the flaw was a manufacturing one rather than a design one. Nothing in the record, the court said, let a jury draw that narrower inference.
Having run the case that way, the court held, Citation was "stuck with the consequences of that approach."
