Boston Steam Pipe Explosion

Two workers and two pedestrians have been hosed down by public safety officials in downtown Boston following a manhole explosion that's raised concerns about asbestos exposure.

The steam pipe blast erupted at the corner of Otis and Summer Streets near Downtown Crossing.

The area's been closed to pedestrian and auto traffic.

Boston Fire Chief Ken O'Donnell says crews are trying to prevent any more asbestos from getting into the air.

The incident comes less than two months after Mayor Thomas Menino called for stricter regulations of the city's underground steam pipe system, following a fatal pipe explosion in New York.