Water fountains in one part of Cleveland Hopkins International Airport have been shut down following a handful of passengers falling ill on a flight from Cleveland to Tampa on Tuesday, NBC reported.

According to CNN, six passengers on Frontier Airlines Flight 1397 suddenly became ill around the same time while the flight was still in the air. The six passengers were not traveling as a group, but exhibited the same symptoms. Michele Dynia, a spokeswoman for the airport, told CNN that no other passengers on the flight were sick.

Once the plane landed in Tampa, all sick passengers deplaned and were checked by medical staff before officially being released. Other passengers on the flight had to remain on the plane until clearance was given about an hour and a half after landing, according to CNN.

“Once our medical team determined the passengers weren’t contagious, everyone was released from the plane and the airport. No one was transported from the airport to local hospitals,” TPA vice president of communications Janet Scherberger told The Points Guy in an email.

Scherberger told CNN that the affected passengers experienced nausea and vomiting by the time the plane landed in Tampa. While an investigation is still underway, officials believe that the passengers’ illness could have been caused by airport water fountains in the Frontier airport concourse in Cleveland.

Water fountains have been taken offline in order to prevent any further illness, according to CNN.

Though the tap water in airports is not exactly the same, water in airplanes can certainly run passengers the risk of getting ill, which is why may passengers do not order coffee or tea on flights, and some airlines do not serve water from the tap.

It’s best to use plenty of caution when it comes to your health while flying.