PITTSBURGH — Police and fire marshals have been trying to determine what caused an empty Pittsburgh house to explode, blowing massive holes in both sides of the older two-story home.

The explosion occurred in the city’s Oakland section, which is near the campus of the University of Pittsburgh and several other schools.

Fire Battalion Chief Jim Dolan says the damage was so severe the house was in danger of collapsing by the time firefighters arrived.

No injuries have been reported, and the search for a cause is continuing.