Billowing smoke and flames drew gaping looks from crowds of students outside Memorial Hall around noon yesterday, when a Boston College shuttle bus burst into flames on Cambridge Street.

Cambridge Deputy Fire Chief Gerald R. Reardon said the flames may have been caused by an electrical fire near the driver's seat of the bus, although the exact cause of the accident is still under investigation.

The driver was the only person on the bus when the incident occurred and was not injured, he said.

According to Reardon, the driver pulled over just before noon when he smelled a burning odor, exited the bus and contacted the fire department.

"He did exactly what he was supposed to do given the situation," Reardon said.

A small fire continued near the driver's seat until the flames consumed the rest of the bus, sending a thick cloud of black smoke and a foul odor into the air, witnesses said.

"I was in Loker [Commons] and smelled something burning," said Lisa R. Racki '03. "I ran outside and saw this huge cloud of black smoke."

The Cambridge Fire Department arrived on the scene after the bus had been burning for nearly 10 minutes and quickly put out the fire.