A Harvard shuttle bus borrowed by Phillips Brooks House (PBH) burst into flames near Medford last week, but with no loss of life or injury to the 30 young children and counselors in the vehicle, sources said yesterday.

The PBH driver, Michelle J. Sypert '88, heard noises coming from the engine Friday morning while on Route 93 and quickly evacuated the children before fire engulfed the vehicle.

Soon after the counselors evacuated the children, "the bus burst into flames and burned up," PBH President Shawn MacDonald '88 said yesterday. "Eventually the whole bus burned."

It has become common practice for PBH to borrow the shuttle buses under an informal agreement with the University, MacDonald said. A Harvard official said yesterday that he was unsure what liability, if any, the University would have assumed if any children were injured.

The cause of the fire was undetermined yesterday.

The accident was the second potentially disastrous one to involve PBH in as many weeks. On July 22 a PBH van flipped over a Mass. Turnpike guardrail while filled to nearly double legal capacity with 26 children participating in a different program.

However, MacDonald emphasized that the shuttle bus was not overcrowded with the children, who were en route to a New Hampshire summer day camp as part of PBH's Inner City Outreach program.

In addition, Sypert was licensed to drive shuttle buses, and does so during the academic year, according to Manager of Central Services at Facilities Maintenance Frank Rose, who overseesthe shuttle buses.

"We're just thankful Michelle had he presenceof mind to pull over when she heard funny noises,"said MacDonald. "It's just really lucky all hekids were out of [the van]."

The cause of the blaze is as yet undetermined,according to Rose.

"Anything we might say right now would be pureconjecture," said Rose, who is directing thepending investigation. "The bus is so badlycharred it's difficult to figure out whathappened."

Sypert could not be reached for commentyesterday.

PBH customarily uses the shuttle houses inaddition to its won vehicles. "We loan our shuttlebuses to PBH in the summertime as long as theyprovide drivers trained by use," Rose said.

The shuttle bus was one of a fleet of five.During the academic year the buses are used toshuttle students to numerous stops between theQuad and Mather House.

It will take 10 months to replace the bus, Rosesaid. However, shuttle bus services in the fallwill run as usual using a spare bus, Rose said