The bus was engulfed in flames on northbound Baltimore-Washington Parkway, causing major delays and cars to veer off the road behind the incident, fire officials said.
"Paramedics described everyone as being in good condition even though some of the children may have been exposed to smoke. No actual injuries have been reported. All the children and their teachers are accounted for," fire officials said.
The students are from an academy school in NW Washington DC that were on-board for a field trip, officials said.