FULTON, N.Y. — The death of a school bus driver who fell from a co-worker’s bus was ruled accidental, police announced.

Investigators said that Brenda Phillips, 51, was conversing with other drivers in a bus that was being driven around the circular driveway of a junior high school on Jan. 16. She apparently fell while standing in the stairwell, descending through the door and onto the pavement.

Phillips sustained a head injury and was transported to local hospitals, where she died that evening.

The death was deemed accidental based on preliminary findings from the local medical examiner’s office.

Fulton Police Chief Mark Spawn told the Fulton Daily News that witnesses said the bus was moving slowly and that the door was closed. He said it was unclear what caused Phillips to fall, but the incident was still under investigation.

Phillips had been a school bus driver for several years. For the past six years, she worked for Golden Sun Bus Service.