A school bus fire on the side of Route 22 caused traffic problems and delayed a field trip Friday morning in Northampton County.

The incident happened around 9:20 a.m. in the westbound lanes between Routes 512 and 191 in Bethlehem Township.

Northampton County Communications supervisors tell Channel 69 News that students were safely evacuated off the bus.

No injuries were reported, but traffic was slowed on both sides.

The bus is from the Phillipsburg (NJ) School District and according to school officials, was one of three buses transporting students on a field trip to the Lehigh Valley Zoo.

Staff and the bus driver smelled something, and after pulling over, they saw smoke and small flames coming from the front wheel area of the bus.

A staff member used a fire extinguisher to put out the fire, and the students were loaded onto the other two buses.

They continued to their field trip, and officials said the students would be back at school at their normal time.