Delta flight attendants are suing Boeing over an aircraft system they say exposed them to "toxic" air, the Chicago Tribune reported.

The plaintiffs claim that the bleed air system used by most Boeing aircraft that takes air from the engines to power air conditioning and pressurization systems in the cabin is at fault.

The incident in question occurred on a flight from Frankfurt, Germany, to Detroit, Michigan, operated by a Boeing 767-300ER aircraft.

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Delta flight attendants are suing Boeing following an incident where they claim "toxic" air flowed into the cabin during a routine flight, the Chicago Tribune reported.

The lawsuit alleges that the aircraft's bleed air system, which takes air from the engines to feed the aircraft's air conditioning system and pressurize the aircraft, was responsible for the event and Boeing as the manufacturer is at-fault.

The flight attendants filed the lawsuit Tuesday in Boeing's home turf of Chicago, taking the matter to Cook County Circuit Court where they will ask for $50,000 in damages related to the incident and a trial by jury, the Tribune reported.

The incident in question allegedly occurred during a routine flight from Frankfurt, Germany, to the airline's hub in Detroit, Michigan, where the crew noticed decreasing air quality while in the middle of its transatlantic crossing, the AvHerald reported.

The bleed air that is taken from engines is supposed to be clean air, but potentially leaks in the engine can cause contamination, Inc reported. An aircraft's engines are constantly sucking in air as it's required to produce thrust, making them an ideal source for cabin air when functioning properly.

But the system has been the focus of numerous lawsuits over the years, with cabin crews at the forefront. Alaska Airlines flight attendants sued Boeing over the issue, the Chicago Tribune also reported, just five years ago in 2015. The matter was settled out of court.

In the latest case, the aircraft operating the flight was a Boeing 767-300ER aircraft, one of Delta's long-haul workhorse.

Boeing aircraft aren't the only ones featuring the system, however, as its main rival uses the same type of bleed air system for its aircraft, even its newest ones. Two operators of the Airbus A330-900neo, TAP Air Portugal and Aircalin, both reported fumes on board the aircraft, matching the description of a bleed air issue, with New Caledonia-based Aircalin sending its aircraft back to France for tests shortly after taking delivery.

Boeing and Delta did not immediately respond to a request for comment.