U.S. investigators are looking into why a SkyWest Inc. airplane with 75 passengers was forced to make an emergency landing in Buffalo, New York, on Wednesday.

The Federal Aviation Administration said in a statement that the flight crew reported a pressurization problem and declared an emergency before landing safely. While a SkyWest spokeswoman said one passenger lost consciousness during the flight, the airline disputed news reports that a door had opened on the aircraft.

There was no indication that the plane lost cabin pressure, the SkyWest spokeswoman, Marissa Snow, said in an interview.

The flight was en route to Bradley International Airport in Connecticut from Chicago's O'Hare International. The plane, an Embraer SA regional jet, was diverted and landed safely in Buffalo at 11:40 a.m., the FAA said in its e-mailed statement.

The passenger who lost consciousness received medical attention at the airport and SkyWest is working to put the remaining 74 passengers on other flights, Snow said.