Investigators are still trying to figure out what made half a dozen passengers on a British Airways flight faint early Saturday morning.

Airline spokesman John Lampl told the "New Jersey Star-Ledger" the incident happened at the end of a flight from Newark, New Jersey to London.

Flight 184 left Newark at around 7:30 p.m., Eastern time Friday and was in the air for a little over seven hours.

An ambulance met the plane on the runway at London's Heathrow Airport around 6:40 a.m., local time, but no one had to be hospitalized.

Lampl said police and fire officials searched the plane, but were unable to find any suspicious chemicals or gases. Food has also been ruled out as the cause of the fainting incident.

The airline's investigation is ongoing.