A field trip turned into a frightening, fiery ordeal for some Mahopac preschoolers Monday in Lewisboro.

The children were on their way to an aquarium when the bus they were riding in suddenly caught fire along Route 35 around 11:30 a.m. The driver said motorists saw the smoke and flashed their headlights to alert him.

"Half of them were asleep, but we got them all to safety," a chaperone said of the children. "They did great."

Fire officials arrived at the scene just after the fuel tank exploded. It took crews from Katonah and South Salem about 30 minutes to get the flames under control. Authorities believe an electrical problem was to blame.

The incident closed traffic for almost an hour in both directions.For interviews and footage about the bus fire, go to channel 612 on your digital iO cable box and select iO Extra.