A Seattle-Tacoma International Airport spokesman says passengers aboard a United Airlines flight from Chicago were held on the plane for more than an hour after landing Monday night while a doctor assessed a sick passenger's ailment.

Airport spokesman Perry Cooper says the passengers were released after an airport-based doctor with the Centers for Disease Control and Prevention decided the passenger had food poisoning. Cooper says the passenger had vomited twice during Flight 1454.

United spokesman Rahsaan Johnson said he had no information on what caused the food poisoning for the female passenger. He says there were 162 passengers aboard the flight.

Cooper says the CDC doctor was concerned about the symptoms and the decision was made to hold the passengers on board the plane in case the ailment turned out to be something more serious. He says the plane landed about 7 p.m. PDT and passengers were allowed to leave at about 8:25 p.m.