Colorado Workers' Compensation Law Bars Flight Attendant's Toxic-Fume Claims Against Frontier Airlines

DENVER (LN) — U.S. District Judge Philip A. Brimmer on Thursday dismissed plaintiff Linda Kilkenny's claims against Frontier Airlines, ruling that Colorado's Workers' Compensation Act bars her gross negligence and fraud claims against the carrier. Because the act barred every claim Kilkenny brought against Frontier, Judge Brimmer also held that Frontier had been fraudulently joined and denied the plaintiffs' motion to remand the case to state court.

Kilkenny and co-plaintiff Lita A. McKay, both Frontier flight attendants, alleged they were poisoned by aerosolized engine oil and hydraulic fluid during a November 9, 2023 flight. According to the complaint, the aircraft was scheduled to fly from San Diego to Denver and, after a brief ground stop, from Denver to San Antonio. While en route to San Antonio, the flight attendants noticed a smell described in the complaint as nail polish, citronella, or dirty socks before falling ill. The pilots declared an emergency, and the crew sat on the jetway for six hours awaiting medical attention before being taken to a hospital, where, according to the complaint, elevated carbon monoxide levels indicated carbon monoxide poisoning. The complaint also alleged that the same aircraft had experienced a fume event one week before the November 9 flight.

The suit, filed in Denver state court in November 2025 and removed to federal court by Airbus the following month, also names Airbus Americas, Airbus S.A.S., Honeywell International, and Honeywell Aerospace US LLC as defendants on product-liability theories. Only Kilkenny's claims against Frontier were at issue in Thursday's ruling.

Judge Brimmer rejected both exceptions Kilkenny invoked to escape the WCA's exclusivity bar. On the intentional-tort exception, he relied on Digliana v. City of Fort Collins, a Colorado Court of Appeals decision holding that employer awareness of a toxic-fume hazard and failure to remedy it — even combined with allegations of concealment and inadequate medical response — does not amount to a deliberate intent to injure. Kilkenny's gross negligence claim presented a similar factual picture, Judge Brimmer held, and likewise failed to allege that Frontier deliberately intended to cause her injuries.

The fraud claim fared no better. The complaint itself alleged Frontier concealed fume-event risks for profit, not to cause injury — a distinction that, under Colorado law, takes the conduct outside the intentional-tort carve-out.

Kilkenny also argued that Frontier retaliated against sickened flight attendants by denying pay, refusing workers' compensation, and terminating employment — conduct that Colorado courts have held falls outside WCA immunity. Judge Brimmer was unmoved: that allegation appeared only brief, not in the complaint, and he declined to consider it. The wrongful-discharge exception recognized in Lathrop v. Entenmann's Inc., he noted, is limited to employees discharged specifically for pursuing a workers' compensation claim — a theory Kilkenny never pleaded.

Because the WCA barred every claim against Frontier, Judge Brimmer also denied the plaintiffs' motion to remand, holding that Frontier had been fraudulently joined and its Colorado citizenship could be disregarded for diversity purposes.

The dismissal was with prejudice. A proposed amended complaint Kilkenny had already filed added no new allegations that Frontier intended to injure her or that it discharged her, leading Judge Brimmer to conclude that further amendment would be futile.

The case against Airbus and Honeywell — on theories that a history of fume events in Airbus aircraft using Honeywell auxiliary power units stretches back decades — remains pending.