A passenger jet flying from Heathrow to Philadelphia has diverted to Dublin "due to an odour caused by a spilled cleaning solution in the galley", American Airlines said.
American Airlines flight 729 landed safely in Dublin and was met by medical personnel.
The airline said two crew members and one customer were taken to hospital "for evaluation".
Two of the plane's cabin crew temporarily lost consciousness as a result of the spillage, according to a recording of a call to air traffic control.
In the recording, which was posted online by the Twitter account @AirportWebcams, one of the plane's crew could be heard asking for paramedics to brought on board once it landed in Dublin.
"Two of our flight crew staff... the cabin staff have actually lost consciousness, I think they're back to consciousness now," he said.
"There are general complaints about burning eyes and other problems with mucus in the nose and skin problems."
According to the crew member, it had been caused by a "cleaning product used at Heathrow Airport" which had been left behind in the toilets and since spilled and seeped into the carpeting.