FORT LAUDERDALE, Fla. (VINnews) — Four flight attendants became ill Thursday aboard a Frontier Airlines flight from Cleveland to Fort Lauderdale, prompting the pilots to request medical personnel at the Florida airport.

Frontier Flight 1046 departed Cleveland at about 7:53 a.m. with up to 230 passengers aboard. As the aircraft approached Fort Lauderdale, the crew contacted air traffic controllers and requested emergency medical assistance.

The pilot reported that the flight attendants were experiencing headaches and nausea, according to an aviation report detailing the radio communication.

The Airbus A321 landed safely at Fort Lauderdale-Hollywood International Airport and proceeded to its assigned gate, where medical responders were waiting.

The aircraft had been scheduled to operate a return flight to Cleveland later Thursday morning. That flight was canceled, along with another Frontier flight between Cleveland and Fort Lauderdale scheduled for later in the day.

The reason the flight attendants became ill was not immediately clear. Frontier did not immediately provide a statement explaining what happened.

The incident could raise questions about possible air-quality or fume issues aboard the aircraft, although there was no immediate evidence establishing that fumes or contaminated cabin air caused the illnesses.

Airline industry experts have long examined so-called fume or odor events, in which odors or chemical substances can enter an aircraft’s cabin through its ventilation system. Such events have generated disputes and lawsuits involving aircraft manufacturers and airlines.

The flight arrived safely, and there were no reports in the available information of a serious medical emergency involving passengers.