ST. LOUIS (AP) — Part of St. Louis Lambert International Airport was evacuated for two hours after the roof caught fire.

No one was injured. Firefighters are working to determine what caused Sunday’s blaze.

Officials evacuated the area near where the fire happened. Terminal 1 was closed for about two hours, but Terminal 2 continued operating. Several flights were delayed.

Airport spokesman Jeff Lea says the fire was between the top copper layer of the roof and the structure underneath.

Photo by Bill Greenblatt/UPI