LOS ANGELES — On Wednesday morning, students were being transported on a freeway here for a field trip when their school bus broke down and caught fire. 

A teacher who was on the bus at the time of the incident told KFSN that smoke poured into the cabin from the front of the bus, so the emergency doors were opened and the students were moved to the back of the bus.

"It was progressing really rapidly, and we were on the freeway so we were afraid to get out," teacher Cathy Peters told the news station.

However, as the smoke grew thicker, everyone on board was forced to evacuate onto the freeway. Motorists helped get the students out of the bus, which by this point was engulfed in flames.

Two students complained of smoke inhalation, but no one was seriously injured. The California Highway Patrol is investigating the cause of the fire.