Boston School Buses Stopped by Cement Factory Accident

Parents of students who ride Boston Public School buses are being advised to be prepared for significant delays in school bus transportation.

More than 60 people, many of them school bus drivers, were sent to Boston area hospitals after cement dust from a nearby factory was released, covering hundreds of buses at the bus yard in Charlestown. The yard serves about a third of the school department's bus fleet.

Officials are investigating what caused the cement plume to erupt from the factory.